This study addresses the need for real-time source apportionment (RT-SA) to improve responses to acute pollution events. Traditional SA methods have limitations, including low time resolution and delayed post-analysis. This research implements two RT-SA models in four Chinese cities (Xi’an, Chongqing, Beijing, and Wuhan), using a combination of ACSM, Xact 625, and Aethalometer instruments to quantify PM sources. A newly developed RT-SA software, alongside SoFi RT. RT SA enables near-instantaneous identification of organic and inorganic PM fractions. Comparison with state-of-the-art techniques confirms their reliability, demonstrating RT-SA’s potential for real-time air quality monitoring and improved urban pollution mitigation strategies.

The aim of this work was to study the diurnal variation of elemental components, black carbon and sources of PM_2.5 as well as their size-distribution in Debrecen, Hungary. PM were collected with two-stage PIXE International sequential “streaker”. During some campaigns, an Aethalometer and an OPS were also used. The elemental composition of the samples was determined by PIXE at INFN LABEC. SA was performed on obtained data using PMF model. The main advantage of combining the applied methods is that it can enhance our understanding of the sources of PM and their effects on different size fractions of PM_2.5.

A source apportionment of the urban-background site of Lecce, Italy, was realised using aerosol physical properties such as size distributions and aerosol absorption data from 2016–2017. Results were compared with chemical PMF analysis performed in the same period. The study highlights the strengths of physical PMF in capturing ultrafine particle dynamics and traffic-related emissions with a fine time resolution but notes its limitations in distinguishing biomass burning from fossil fuels. Overall, physical PMF complements chemical PMF, offering advantages such as real-time monitoring and simpler data collection, making it a valuable tool for air quality assessment.

Romania's Bucharest faces air pollution issues. RADO-Bucharest, a three-component ACTRIS national facility, provides the opportunity to assess the levels and properties of contaminants within a region using high-time resolution data. The 10-year analysis of carbonaceous aerosols mass concentration daily variability at site points to biomass burning as a source of increased concentrations during the cold season. Mobile monitoring campaigns were performed during the warm and cold periods to capture air pollution variability in Bucharest. The retrieved air pollution maps show the contribution of diverse areas to air pollution, gradients in particle concentrations between areas, and individual exposure along roads.

African nations have part of the economy informal with street dealers selling goods while being exposed to pollution from vehicles. A survey was conducted to assess their level of awareness and exposure to particulate matter in the city of Thiès, Senegal. A Particle Plus 8301-AQM2 Series measured particles concentrations. More than 40% of participants declared to be often affected by cough, headaches, cold and sore throat. Measured PM_2.5 and PM₁₀ concentrations were in the range of 25-75 and, 250-700 µg/m³, respectively. Therefore, it is recommended that measures being taken to inform and help street dealers monitor their health and safety.

In this paper, the use of the model organism D. melanogaster is proposed to study PM-induced adverse effects. Individuals of D. melanogaster were exposed under laboratory conditions to increasing concnetrations of brake dust and in situ in an art ceramic factory at 4 selected sites each representative of a different work process. For both exposures analyses included element bioaccumulation, antioxidant enzymes, NMR metabolomics, and oxidative stress were performed. Results showed metabolic alterations and oxidative stress, varying by exposure. D. melanogaster bioaccumulation correlated with PM₁₀ composition. This highlights D. melanogaster's potential as a PM toxicity assessment tool.

A case study in Mordelles (France) examined the relationship between airborne pesticides and agricultural activities using a monitoring station. Data on pesticides use came from a national sales database, while farming practices were gathered from a local survey and meteorological data from official records. Herbicides, especially prosulfocarb and pendimethalin, showed seasonal peaks, linking application periods to air concentrations. The detection of banned lindane highlights its persistence. Triallate, though not sold or applied locally, was also present, demonstrating pesticide mobility. Additionally, the survey identified 54 unmonitored substances, revealing the need for adaptations in national surveillance lists to better reflect regional practices.

In this study, we ran the FLEXPART-SOSAA model during and after a severe haze episode in Beijing. We found that as much as half of the particles originated outside of Beijing, and 5% of the primary mass and 8% of SOA mass originated in Xinjiang region in far western China. We also tested several scenarios related to potential emission control strategies that could mitigate the severity of haze episodes.

The study applies the COSMO-MUSCAT model to analyse PM sources at sites in Germany and the Czech Republic. The model underestimates PM2.5 concentrations, possibly due to unaccounted emissions from Saharan dust intrusions and stagnant, cold weather conditions. A tagging method identifies emission sources by sector and country, highlighting domestic heating as a major winter contributor. Further sensitivity tests reveal underestimated SOA formation from aromatic VOCs during wood and coal combustion. Seasonal comparisons provide insight into model performance, with future improvements planned through the integration of a Heating Degree Day approach to better capture heating-related emission variations.

Is there a link between industrial-era air quality and contemporary socio-economic outcomes in German cities? Answering this question requires spatial data on urban air pollution at the end of the 19^th century. The regional chemistry-transport-model ICON-MUSCAT is used to model historical air quality in Germany using an improved emission dataset based on the emissions of the Community Emissions Data System (CEDS). Improvements of the spatial distribution of the sector-wise emissions are performed with the help of population data and historical maps that provide the location of factories etc. within the city, as well as the extent of populated areas.

The study assesses aerosol formation sources through chemical analysis and emission inventories, focusing on nanoparticle precursors using inverse modeling techniques. It examines five aerosol precursors in Estonia. SO2 is monitored at multiple stations, while H2SO4, HIO3, and two highly oxidized organic molecules (HOMs: C10H15NO8, C10H14O9) were measured at the SMEAR Estonia station from 2019 to 2023. Data from April to November 2019 are used in this research. The SILAM v5.7 model was used to detect aerosol precursor footprints, processed using a Time-Of-Flight mass spectrometer and TofTools software.

New particle formation is a key source of CCN, influencing cloud properties and climate. In this study we provide insights into NPF driven CCN production in Cyprus. Our findings indicate that CCN enhancement occured on 80% of the NPF days observed during the SPICY campaign in Cyprus in spring 2024, exhibiting a factor 2 concentration increase on average. On non-event days, no CCN concentration enhancement was observed. These results highlight the role of NPF in enhancing CCN concentrations in the eastern Mediterranean during spring, with potential implications for regional cloud microphysics and climate.

The CAINA project investigates multiple aspects of aerosol-cloud interactions under high reactive nitrogen concentrations, combining ambient, chamber, and modeling studies. First highlights include:

2-year measurements show strong new particle formation and growth to CCN sizes at two contrasting sites in the Netherlands.

Studies at the AIDA chamber show that SOA mass yields are strongly enhanced at 90% RH compared to dry conditions, with strong evidence for aqueous SOA formation. At 90% RH the SOA composition clearly depends on inorganic components in the solution droplets with NH₄NO₃ enhancing production of oxalic and malonic acid, as well as nitrogen-containing organics.

We present and interpret the findings from our size-resolved cloud condensation nuclei measurements from Budapest. The system has been running since August, 2024, so far, six months of data have been collected. We observed different atmospheric events deviating from the average, normal environments, like fireworks, regional and localized nucleation originating from flooding, running races and the washing-out effect from raining.

This study presents a quality-assured, long-term database of CCN concentration, activation properties, particle number size distribution, chemical composition and optical properties from 10 DOE ARM sites. The data reveal significant spatial and temporal variability in aerosol properties influenced by local environments and specific sources. To address CCN data gaps, we evaluate CCN predictive models using chemical and optical properties. A new model capable of estimating CCN concentrations from common optical measurements is presented, aiding climate modelling and reducing ACI uncertainty.

Traffic remains an important source of particulate matter with non-exhaust currently estimated to make up a greater proportion of vehicle emission by mass than exhaust. The new Euro 7 standard will include non-exhaust emissions; to assess its impact it is crucial to have a good understanding of current emissions.

Here we utilise the high time resolution aerosol measurements to carry out source apportionment, which is combined with machine learning and NO₂/CO₂ dilution approaches to estimate non-exhaust emission factors.

Preliminary results show that 7.9%, 2.0% and 2.3% of PM₁₀ at the roadside is brake, tyre & road and train wear, respectively.

This study applies advanced receptor modeling using the multilinear engine (ME-2) within Positive Matrix Factorization (PMF) to apportion PM_2.5 sources in the Los Angeles Basin. Unlike Aethalometer optical method, this approach extracts source-specific Absorption Ångström Exponents (AAE) without a priori assumptions. A comprehensive PM_2.5 chemical dataset and multi-wavelength absorption coefficients were analyzed at urban (CELA) and suburban (RIVR) sites. Five-source factors were identified, with secondary sulfate and nitrate dominating PM_2.5 mass. Source-dependent AAE values varied by location, ranging from 1.24 to 3.0, highlighting differences in emission sources and atmospheric processes between traffic-dominated urban areas and suburban environments.

To better characterize Organic aerosol (OA) sources, online measurements from the Aerosol Chemical Speciation Monitor and organic tracer analyses were carried out in 2019 at two urban background sites in France (Lyon and Bordeaux) and combined using the novel “multi-time” Positive Matrix Factorization (PMF) approach. This analysis separated secondary sources from biogenic and anthropogenic emissions. It also highlighted local sources, identifying cooking in Lyon and a marine source of OA in Talence, and provided a more accurate contribution from primary sources, which are underestimated in individual online PMF.

We developed a completely novel multi-time and multi-size resolution PMF (MTMS-PMF) implemented in a script for the Multilinear Engine ME-2 program. This cutting-edge model is an expansion of the PMF and allows the analysis of data measured at different time resolutions in multiple size classes. Moreover, both size-segregated data and PM_X data can be inserted at the same time in the model. As output, the MTMS-PMF provides size-segregated chemical profiles and factor temporal contributions retrieved at the highest temporal resolution available in the dataset. The MTMS-PMF was successfully tested on a large dataset collected in the Po Valley (Ferrara, Italy).

Ultrafine particles (PM0.1) can penetrate sensitive organs and pose health risks, but measuring their chemical composition is challenging due to low mass concentration and interference from larger particles. Traditional methods using cascade impactors have limitations in temporal resolution and labor demands. This study used an Aerodynamic Aerosol Classifier (AAC) to isolate PM0.1, followed by instruments for continuous composition measurements. Field campaigns in Greece revealed different PM0.1 chemical composition profiles: Poros (background site; secondary formation, sulfate-dominated) and Athens (urban site; traffic, biomass burning, and cooking sources). The temporal variations in concentration, composition, and sources at both locations have been analyzed.

Measuring the compositon of aerosol particles at the start of their formation, when they are only several nanometers large, is interesting as it reveals what vapours specifically contribute to nucleation. However, attaining molecular information is difficult due to low masses and the requirement of soft ionization. In this study, we employ a novel DMA-VIA-MION-Orbitrap setup to characterize the composition of size-selected aerosol particles in the laboratory and ambient measurements. We present first results from a deployment of the novel approach to Mace Head, Ireland, where marine VOC emissions and the composition of 10-20 nm particles were targeted.

Ultrafine particles affect climate, by growing to cloud-forming sizes, and pose health risks due to their deep body penetration. However, because of their low mass, chemical characterization of such small particles has been a challenge to date. A lot of knowledge of chemical composition has been obtained from offline measurements, where the time resolution is lowered to the filter collection time. In low-concentration environments, this can be as long as weeks. Here, we show that nanoelectromecahnical systems coupled to fourier-transform infrared spectroscopy can enable both chemical characterization of ultrafine particles and shortening collection times to minutes-hours in pristine environments.

The Xact625i instrument is increasingly used for measuring trace elements in atmospheric aerosols due to its capability to produce Near-Real-Time measurements. Despite its advantages, discrepancies with respect to reference methods (ICP-MS) highlight the need for a robust calibration approach. Results from a Round-Robin exercise involving 10 Xact625i within ACTRIS-ERIC and MI-TRAP will be presented. Partial results show strong correlations and over/underestimation for some elements. Xact625i measurements were compared with reference-free PIXE and XRF. These results will provide comprehensive information about the inter-comparability of different instruments and represent a first step towards the definition of robust QA/QC procedures for Xact625i.

Recent advances in sensing technologies and community engagement have resulted in mobile air quality monitoring tools, enabling data collection at unprecedented scales. This study presents outcomes from mobile monitoring campaigns with citizens carrying portable instrumentation for black carbon (BC), ultrafine particles (UFP) and particulate matter (PM) in Rotterdam (NL), Barcelona (ES) and Warsaw (PL). Results show spatiotemporal and seasonal variability of the pollutants and allowed identification of specific cold- and hotspot locations. A data processing workflow for mobile air quality measurements is proposed including (i) instrument validation, (ii) spatial aggregation and (iii) temporal correction to obtain representative air quality maps.

This study compares the performance of machine learning and land use regression models to estimate the concentration of Black Carbon (BC), Ultrafine Particle Number Concentration (PNC), PM_¹⁰, and PM_2.5 in Zurich City, Switzerland. High spatial resolution (50 m x 50 m grid) models were succesfully developed and externally validated. Among four algorithms (LM-LUR, GAM, RF, XGBoost), RF stands out as the most optimum with fair R² range of 0.74 - 0.87 for four pollutants. All models were derived from small-scale monitoring campaign utilizing low-cost sensors. This approach could be implemented in country/ city with lack of large scale monitoring network.

Children are particularly vulnerable to indoor air pollution and school environments significantly contribute to their overall exposure. This study, part of the InChildHealth project, examined PAH and BC levels in schools and homes in Barcelona, located in different areas. Results showed higher concentrations in urban intensive-traffic sites in colder months and rural areas that were affected by wood combustion. Poor ventilation and indoor activities like smoking also contributed to PAH accumulation. Moreover, a strong correlation between BC and high-molecular PAHs (R²=0.74) suggests common sources. These findings highlight the need for better air quality policies to effectively safeguard children’s health.

The Berlin-Brandenburg Air Study (BEAR) is the first study in Germany to comprehensively assess short- and long-term AV-UFP exposures and their potential health effects. The study specifically examines pulmonary, cardiovascular, and cognitive health outcomes in primary school children. As part of BEAR, extensive particle number concentration (PNC) measurements were conducted at multiple schools in Berlin and Brandenburg from 2020 to 2024, providing an opportunity to analyse UFP exposure near two international airports. The exposure assessment results will play an important role in forthcoming epidemiological investigations, offering a holistic understanding of airports’ impact on health implications.

This study deals with aerosol synthesis of carbon nano onions (CNOs) containing TiO₂ with oxygen vacancies and investigation of their morphological and optical and photocatalytic features. The CNO composites were synthesized employing closed flame spray process and as obtained material was investigated using TEM, Raman spectroscopy, FTIR, Thermal optical carbon analyser, TGA and UV Vis absorption analysis. Results show that that CNOs exhibit concentric graphitic layered structures containing mixed phases TiO₂ with oxygen vacancies. Incorporation of TiO₂ leads to defects induced structure in CNOs and results in extended absorption in visible region, rendering promising material for photocatalytic and photochemical applications.

Flame spray pyrolysis (FSP) systems are getting an increasing level of attention because of their capacity to produce nanoparticles with well-defined characteristics for the production of innovative materials. To achieve good control of nanoparticles characteristics, a deep understanding of the processes governing their production in the flame is required. To this end, we have developed an experimental setup enabling us to study of TiO₂ synthesis in a laminar H₂/TTIP/air diffusion co-flow pre-vaporized flame. In this contribution, we will illustrate how to combine in-situ optical diagnostic, ex-situ measurements and detailed computational fluid dynamics to obtain new fundamental insights on flame synthesis.

Molecular dynamics (MD) simulations of air molecules accounting for their shape and force fields revealed recently that inelastic collisions are abundant. Here, fully atomistic MD simulations are conducted to assess the diffusivity of silica nanoparticles (NPs) in air. As NP size approaches that of air, NP diffusivity is increasingly affected by inelastic collisions, resulting in various collision patterns like grazing, head-on, and orbiting. The MD-derived diffusivities for sub-5 nm NPs were 50-60% smaller than those predicted by the Stokes-Cunningham-Millikan (SCM) equation. Additional simulations treating NPs and air as hard spheres yielded diffusivities that matched with the SCM equation.

We design a novel monolithic wall-flow reactor with optimized structure that can accommodate an unprecedented O(10) higher amount of catalytic particles (loaded via an aerosol process) vs washcoated technology and exhibit much lower overall flow resistance than a similar packed bed reactor. Prototype reactors loaded with catalytic powders are evaluated with respect to their flow resistance confirming their high potential. Employing rational approximations we obtain an analytical solution for the flow through the monolithic reactor and the dependance of the pressure drop on the parameters of the problem, which is shown to be in excellent agreement with the data.

Detailed observations of aerosol-fog microphysics were carried out at the rural station of San Pietro Capofiume (SPC) in 2021-2022 in the Po Valley, one of the major pollution hotspots in Europe, in the frame of the Fog and Aerosol Interaction Research Italy (FAIRARI) field experiment. The results support the key role of aerosol size distribution in determining activation into fog in this environment. Moreover, continuous measurements of fog liquid water content (LWC) were performed since 1991 every winter allowing the analysis of long-term trends in fog properties.

A field campaign in a mountaintop station of southeastern China used a GCVI and ToF-ACSM to study cloud particle composition. Organic dominated (~60%) across cloud residuals (Res), interstitials (Int), and ambient particles (Amb). Sulfate and ammonium had highest scavenging efficiencies (>60%), while nitrate was enriched in cloud droplets (9.2% higher in Res than Amb). Aromatic hydrocarbons increased during cloud formation, with C₈ aromatics surging 5.95 times on average. Anthropogenic emissions led to larger cloud droplet size. Organic oxidation decreased with increasing organic fraction, highlighting the role of in-cloud aqueous-phase reactions in altering orxidation degree of organic compounds.

The aim of this study is to improve the understanding of in-cloud aqueous secondary organics aerosol (SOA) formation from isoprene under different environmental conditions (e.g., temperature, OH exposure, NOx levels) including representing convective systems, using a Teflon chamber for photo-oxidation and a wetted-wall flow reactor (WFR) where the presence of a cloud was mimicked by a thin water microlayer.We will present first results of the chemical composition of the liquid microlayer, compare that to the gas-phase composition, and put the results in perspective of recent ambient direct observations in high-altitude Amazon air masses.

Cloud water samples and snow samples collected at the Sonnblick observatory at "Hoher Sonnblick" in the Austrian alps were analysed via HPLC-MS/MS, for 20 PFAS mentioned in the EU drinking water guidelines, and related to available literature.

In the study, chemical compositions and OP of PM₁₀ and PM_2.5 were observed at an urban background, urban traffic and train station sites in Reims (France), that are located 5km apart. The 24-hour sampling was taken in winter and summer. A wide range of chemicals was analyzed (carbonaceous, major ions, elements, alcohol sugars, organic acids), OP assays: AA, DTT, OH. These species were used to perform a PM SA, followed by OP SA for both PM fractions.The inter-comparison of PM and OP SA results provide the PM and OP sources according to PM characteristics, receptor site and sampling period

The Working Group of the Italian Aerosol Society worked for having collected PM10 mass and chemical composition data throughout Italy. The dataset was aggregated with seasonal temporal resolution from 2005-2016 and had a heterogeneous origin related to urban sites of large and medium-sized cities in the Po Valley, inland or coastal areas. The collected dataset allowed to assess differences in chemical composition among cities and by different geographical features: for example the Po Valley with respect to the rest of our Peninsula, relating to secondary inorganic compounds.The collection of more PM chemical composition data was extended to recent years.

This study aims to compare the chemical composition of PM2.5 samples from two sites in northern France: an urban-industrial site (Fort-Mardyck) and a rural site (Steene). The origins and the variations in concentrations of chemical components were examined using different tools including concentration roses, conditional bivariate probability function (CBPF), diagnostic ratios, and clustering of HYSPLIT backward trajectories. This study highlights the distinct chemical signature of PM2.5 at the urban-industrial site, characterized by higher concentrations of carbonaceous species and trace metals associated with industrial activities, compared to the rural site.

This study investigated the potential impacts of ship emissions on ambient PM_2.5 in a metro-harbour complex under various meteorological conditions. The research used a WRF-Chem model to simulate multiple days with elevated PM_2.5 levels, revealing a strong correlation between PM_2.5 concentrations and meteorological patterns, during the Asian Northeastern Mon-soons (ANMs) during winter and spring and sea-land breezes (SLBs) in summer. Wind field simulations showed the influences of ANMs and SLBs, exacerbated by coastal topography and wind patterns. Diurnal air temperature variations intensified sea breezes in warm seasons.

The effect of particle size on ice nucleation efficiency at different temperatures is investigated. Ice nucleation experiments were conducted using the SPIN chamber and size-selected dust particles. The measured size dependence is compared with predictions from classical and recent theories. Agreement in size dependence is used as an indicator of which theory best describes the observed ice nucleation mechanism. The results indicate that different ice nucleation mechanisms become active at different temperatures and on different dust types. The general observation of a disproportionately higher ice nucleation efficiency on larger particles should be considered when parameterizing ice nucleation in simulations.

This study presents concentrations of Arctic marine and atmospheric ice-nucleating particles (INPs) at Disko Island, Greenland, from May to September 2023. We investigate the role of indigenous processes and the contribution of terrestrial runoff to biogenic INPs in coastal waters. The results revealed seasonal variations in INP concentrations, with biogenic marine INPs increasing during the summer and melt seasons. Further, we find terrestrial runoff as an important source of biogenic INPs in coastal waters. Atmospheric biogenic INP levels were predominately influenced by the extent of snow cover, underscoring the importance of local terrestrial sources in atmospheric INP concentrations.

This study investigates the role of terrestrial runoff in supplying biogenic ice-nucleating particles (INPs) to the coastal marine environment of Young Sound fjord, Northeast Greenland, and their potential impact on Arctic cloud formation. Using flow cytometry, qPCR, and sequencing, we quantified microbial communities and INP concentrations in water and aerosols. Results show higher INP concentrations in the sea surface microlayer (SML) and river outlets compared to bulk seawater, with significant riverine input of warm-temperature INPs. We also found the SML plays a key role in aerosolizing biogenic INPs, highlighting the need for further investigation into marine contributions for climate models.

The Arctic is warming rapidly, impacting cloud formation and precipitation. Bioaerosols, acting as high-temperature ice nucleating particles (INPs), play a crucial role, yet their representation in climate models remains uncertain. This study presents the first long-term dataset on bioaerosol composition and INP concentrations in the High Arctic (2021–2023). Preliminary results show seasonal shifts in microbial diversity and a strong correlation between airborne bacterial concentrations and warm-temperature INP levels. These findings highlight the need for integrating microbial ecology, aerosol chemistry, and meteorology to refine climate models and improve understanding of bioaerosol-driven cloud processes in the Arctic

The study investigates New Particle Formation (NPF) at the high-altitude Izaña Atmospheric Observatory (2367 m a.s.l.) in Tenerife, Spain, through a three-month campaign (March–June 2022). Results indicate that particle concentrations are influenced by the upward transport of ~20 nm particles from the boundary layer (BL) and local clustering of sub-3 nm particles, which is enhanced by this transport. Sulfuric acid and highly oxygenated organic molecules contribute to NPF and originate from the BL, highlighting its critical role. Additionally, the study analyzes growth and formation rates of sub-3 nm particles, volatile organic compounds, and SO₂ to identify chemical pathways of NPF.

Mineral dust particles have been found to promote clustering and subsequent new particle formation (NPF) in the atmosphere.

Here we investigate the chemical composition and volatility of NPF precursors contributing to the mineral dust-influenced clustering events at a pristine high-altitude location, Canary Islands.

Lower concentrations of NPF precursors were observed for dust-influenced clustering events than clear clustering events. They were most likely to be biogenic origin.

We will compare the chemical composition and volatility of NPF precursors, as well as their potential formation pathways and discuss the resulting effects on particle formation and growth in the presence of dust.

This study explores two decades of ultrafine particle observations at Monte Cimone (2165 m a.s.l.), a key site for monitoring atmospheric processes in the Mediterranean. We analyze particle size distributions and new particle formation (NPF) events, revealing interannual, seasonal, and diurnal trends. Additionally, we examine how meteorological conditions, chemical precursors like sulfur dioxide, and proxies such as VOCs and BC for different emission sources influence particle dynamics and NPF. To assess the role of transport, we integrate FLEXPART backward simulations to trace air mass origins (marine/continental/regional) and evaluate the impact of long-range transport on aerosol properties at CMN.

New Particle Formation (NPF) is a major source of Arctic ultrafine particles (UFP), yet its vertical distribution and drivers remain unclear. This study presents balloon-borne observations of UFP during the 2024 melting season at Ny-Ålesund, Svalbard. Using condensation particle counters and a mobility particle sizer, 45 measurement flights revealed altitude-dependent UFP variability, influenced by temperature, radiation, and wind. Case studies highlight diurnal variations and elevated concentrations between clouds, suggesting in situ NPF. These findings enhance understanding of Arctic aerosol dynamics, improving atmospheric models and climate predictions.

This study presents an inlet system for extending the detection range of the SP-AMS with the added benefit of improved metal detection. The inlet uses Cab-O-Jet 300 particles produced by an atomizer and an agglomeration chamber for agglomerating sampled particles on the Cab-O-Jet 300 particles that can be transmitted into the SP-AMS. Due to higher vaporization temperatures associated with the SP-AMS laser, metals agglomerated on the particles can be measured and their relative ionization efficiencies can be calibrated.

We present a new method to measure the total scattering and extinction cross sections, and optical and mass spectrometry from a single micron sized particle in a touchless environment.

We present a drone-based aerosol sampling platform with fast, high resolution meteorological sensors and a pump-driven filter sampler. The system features streamlined data and power management, including real-time telemetry and remote pump control, ensuring operational integrity and efficiency. A field campaign in Gothenburg, Sweden demonstrated the systems capability in performing targeted aerosol sampling in relation to the development of the nocturnal boundary layer. Aerosl particles were analyzed semi-online using chemical ionization mass spectrometry (CIMS) with a filter inlet for gases and aerosols (FIGAERO). Mass spectrometry analysis revealed compositional differences in ground and aloft samples.

Aerosol droplets are unique microcompartments containing microscopic amounts of material and exhibiting remarkable chemical reactivity. In this presentation, we describe a novel approach for mass spectrometric analysis of individual aqueous picolitre droplets (∼1–180 pL, or ~5-100 µm radius) containing down to ∼1 pg analyte mass per droplet. Individual droplets are generated using a microdroplet dispenser, imparted a small amount of net charge, and guided to the inlet of a high-resolution mass spectrometer using a linear quadrupole-electrodynamic balance. We will characterise the sensitivity of the approach and will discuss experiments investigating accelerated chemical reactions in aerosol droplets.

The aim of the project ElekSim is to include electrostatic deposition and discharging effects for electret filter media in the simulation software GeoDict. Therefore, the relevant separation mechanisms were integrated and numerically validated for single fibres and simple geometries with computational fluid dynamics (CFD) simulations. For more complex structures, simulations on microtomography scans were compared with experiments, yielding good agreement for suitable parameters for the surface charge density and charge distribution on the fibres. Finally, the ageing behaviour of electret filter media under loading with various aerosols was experimentally characterized and implemented in the software.

Understanding the agglomeration of nanoparticles through evaporation-induced assembly is a key process, highly desirable for manufacturers in powder technology. In this study, we evaporate aerosol droplets of monodisperse size containing monodisperse or bi-disperse copolymer nanoparticles of different sizes and shapes. We observe that as the evaporation rate (K) increases, the degree of buckling increases (i.e. the shape transitions from spherical to deformed to dimpled to donut shapes). Moreover, the degree of buckling of dried microparticle increases with increases in the diffusional motion of the nanoparticles while keeping K constant. A similar observation is found for a binary mixture of nanoparticles.

High-voltage electric transmission lines are subject to mechanical stress, weather conditions, atmospheric processes, and pollution, which affect the insulators. Particulate deposits cause inadequate insulation, flashover and failures. A model is being developed at RSE that predicts insulator contamination events through different thermodynamic, meteorological and atmospheric chemistry conditions. Chemical and microphysical characterization, along a vertical profile, of total suspended particulate and of insulator deposits, and source apportionment, were carried at a site of the Italian National Electricity System, aimed at providing experimental datasets for model predictions validation. Results and linkages with sources and weather conditions are discussed in this contribution.

Indoor air quality is a growing concern for both industrial workers and the general population, especially due to pollution and the Covid pandemic. CFD simulations are widely used to assess aerosol dispersion and its impact on air quality. This study investigates aerosol deposition, focusing on the impact of modelling and numerical choices, and more specifically on the Lagrangian tracking schemes. A detailed study highlights how these parameters influence deposition fractions. Recommendations are provided for improving CFD simulations of applied dispersion studies that are numerous especially since the Covid pandemic.

Reactive losses of atmospheric VOCs play important roles in the formation of ozone and secondary organic aerosol (SOA) However, identification of the sources of those VOCs most responsible for the formation of these secondary pollutants is difficult., but essential to produce effective control strategies. VOC apportionment based on measured concentrations has been done for many years and PMF is now the most commonly used tool. Recent work has shown that the "initial concentration", that which would have been present in the abssence of reactions can be calculated and apportioned. The difference is the consumed VOCs than can then apportion SOA.

Particulate matter (PM) exposure is linked to premature mortality and morbidity, making source identification crucial for PM emissions control. Organic aerosols (OA) form a major PM fraction, with secondary OA (SOA) potentially more harmful. Barcelona and Athens, impacted by high population density, intense sunlight, and low rainfall, face severe air pollution. While previous studies identified SOA seasonality, sources remain unclear. To investigate this, we analyzed 180 PM2.5 and 180 PM10 filters (2022–2023) using advanced mass spectrometry (EESI-LToF, AMS-LToF) and positive matrix factorization analysis. Our study identifies OA sources driving fine and coarse particulate variations in these Mediterranean cities.

Munich, a major German city, faces air quality challenges with only limited aerosol studies available. Previous research identified traffic, biomass burning, and cooking as key aerosol sources, yet gaps remain in understanding volatile organic compound (VOC) and organic aerosol (OA) origins and seasonal variations. This study aims to elucidate these sources, enhancing air quality management and public health in Munich. In this study, we examine the seasonal variability of OA and VOC chemical composition at a molecular level, aiming to elucidate the contribution of different sources to major VOC, semi volatile organic aerosol (SVOA) and total OA.

South America is the largest contributor to global biogenic emissions, with vast pristine areas undergoing rapid urbanization, deforestation, and biomass burning. This study used online chemical ionization mass spectrometry at a Bolivian Andes station and Positive Matrix Factorization to analyze organic aerosols from diverse biomes. Five PMF factors were identified, revealing that Amazon air masses are dominated by isoprene SOA, while tropical and mountain grasslands contain longer-chain BVOC-SOA. Organic nitrates increase with population density. Urban emissions and volcanic SO₂ influence aerosol composition, highlighting the strong impact of human activities and volcanic processes on atmospheric chemistry.

PM2.5 samples were collected simultaneously during winter and summer 2021 at three Central European sites—Melpitz (Germany), Kosetice, and Frydlant (Czech Republic)—to assess regional aerosol sources and transport pathways. Winter data showed higher contributions from biomass burning and coal combustion, with Frydlant exhibiting the highest coal combustion signals. Summer samples predominantly contained biogenic tracers, such as arabitol and sucrose, indicating stronger biological sources. Backward trajectory analysis confirmed significant aerosol transport from Eastern Europe. The findings highlight the seasonal shift in dominant aerosol sources and underscore the importance of long-range transport in shaping regional air quality.

This study assessed PM_2.5 and its components at two sites in Lucknow using a mobile laboratory. PM_2.5 levels were significantly higher at the industrial site (198.40 µg/m³) compared to the background site (39.63 µg/m³), with organic aerosols (OA) comprising over 50% at both sites. Positive matrix factorization identified primary and secondary OA sources. A unique industrial-related OA (IOA) factor resolved exclusively at industrial site, contributing 18%, and showed a strong correlation with polycyclic aromatic hydrocarbons and heavy metals. Concentrated weighted trajectory analysis revealed that while secondary aerosols were long-range transported, the IOA was predominantly local, emphasizing industrial emissions impact.

Particle number periodic technical inspection (PN-PTI) has been implemented in several european countries to detect defective diesel particulate filters (DPF) and remove high emitting vehicles from the roads. Gasoline direct injection (GDI) engines are equipped with similar gasoline particulate filters (GPF) which would also benefit from PN-PTI however, it is not yet clear that existing PN-PTI devices can also accurarely measure GDI exhuast due to differences in humidity and particle size. In this study, we examine the effectiveness of existing PN-PTI devices approved for use in Switzerland to detect particles in GDI exhaust in the laboratory and real exhaust.

This study aims to characterize the performances of each among three alcohols to be used in the saturator inlet of a WCPC prototype (model ADI-2021-1, Aerosol Dynamics Inc.) for the detection of sub-5nm naturally charged flame-formed carbonaceous materials. The usage of either nBA, IPA, or EtOH in the saturator inlet results in three different CPC devices relying on two-component condensation, namely the nBA-WCPC, the IPA-WCPC, and the EtOH-WCPC, respectively. The detection efficiency of those two fluid devices is assessed under various flow rates and temperature operating conditions.

This study presents a condensation diffusion charger (CDC) that combines a condensational droplet magnifier with a diffusion charger for particle number counting. Using diethylene glycol, it detects particles down to 2.5 nm with a size-independent response from 10 to 150 nm. Simulations and experiments confirmed droplet growth to ~2 µm, enabling a 20 times signal amplification. The CDC achieves a detection limit of <50 #/cm³ and an upper range of >10⁶ #/cm³. Tested on a chassis dynamo with a motorcycle, it showed strong correlation with a reference CPC (R² = 0.94), demonstrating its accuracy and reliability in particle number detection.

In the standardized calibration method for Differential Mobility Analyzer (DMA), monodisperse aerosols with electrical mobility diameters selected by a DMA are compared to the diameter of size-certified particles. National Metrology Institutes often calibrate DMAs using PSL particles larger 80 nm to avoid interference from surfactant peak. However, to comply with EU’s vehicle emissions and air quality regulations, it is critical to determine the sizing accuracy of DMAs using certified standard aerosols down to 10 nm. In this study, we use size-traceable silver aerosols to demonstrate the concept of DMA calibration down to 10 nm.

We will present new results from our recently introduced Sublimation Particle Counter (SPC). The advantage of the SPC technique is that it does not require the use of any working fluid to measure the total number concentration.

Initial measurements with this new method showed that the total number concentration of the SPC has a good correlation with a CPC for up to 10⁵ cm^-3 nebulised NaCl particles. We also observed a very similar lower cut-off size for NaCl aerosol, but with a much steeper slope from the 90% counting efficiency diameter D90 to the 50% counting efficiency diameter.

This study presents performance evaluation of a CEN-SMPS (CEN/TS 17434 (2020)) that will be used to identify high emitters vehicles in MITRAP project using a combined metric like total particle number (TPN) vs. solid particle number (SPN) . As the introduction of new European emission standards like Euro 6 have led to decrease in the GMDs of transport emissions (50-60 nm), the SMPS was evaluated under the novel fast-scanning mode (1-minute) for the scan range 10-237 nm. The SPN measured by the CEN-SMPS were comparatively closer (9-12% underestimation) to the reference CPC as compared to the TPN measured (17-18% underestimation).

The Environmentally Coupled, Lidar-Integrated Pollution Prognostics System (ECLIPPS), which couples in situ and lidar measurements with global forecasts and regional transport models, has been developed to aid air quality forecasting. ECLIPPS extracts the Integral Length Scale from measurements with the Mini Micro Pulse LiDAR (MiniMPL,), converts backscatter to fine particle concentrations (PM2.5), accesses meteorological data and inputs all these parameters into a transport model to provide air quality forecasts. The ECLIPPS has been used to evaluate aerosol vertical profiles in Mexico City during a period of extremely high PM2.5 due to regional transport of wildfire emissions

The Multi-Angle Imager for Aerosols (MAIA) mission, part of NASA’s Earth Venture Instrument program, investigates the health impacts of exposure to ambient particulate matter (PM). MAIA focuses on 12 Primary Target Areas (PTAs) worldwide, integrating satellite observations with ground-based PM measurements to map PM2.5, PM10, and chemically speciated PM2.5 at 1-km resolution. NASA and the Italian Space Agency (ASI) jointly implement MAIA, with satellite launch planned for 2026. This presentation provides a status update on MAIA’s ground-based monitoring network and preliminary findings, highlighting PM variability across PTAs.

Accurate aerosol quantification is vital for climate modeling, air quality assessment, and aviation safety. This study investigates the volume-to-extinction ratio (ζ) for mineral dust using a unique combination of UAV-mounted optical particle counters, ground-based lidar, and sun photometers. Data from the 2021 Cyprus Fall and 2022 ASKOS campaigns capture diverse dust events from the Middle East and Sahara. Results highlight discrepancies in size distribution retrievals, impacting ζ estimates. Comparisons with MOPSMAP and WRF-Chem-GOCART reveal model limitations. This synergistic approach, combining airborne in-situ observations with remote sensing, provides valuable insights into this important ratio, essential for remote sensing and atmospheric modeling.

Mineral dust chemical and mineralogical composition are key parameters for modeling its earth system impacts. Here, we link the chemical characteristics (full mass closure) of over 25 long-range transported Saharan dust plumes observed at the Jungfraujoch (JFJ) high-altitude research station in Switzerland (3580 m a.s.l.) to their source regions and transport trajectories. Systematic analysis of different satellite-based remote sensing products stands in the centre of identifying these relationships. Clear geographical as well as transport time related trends are observed for different chemical parameters, highlighting the need for differentiation related to source regions and transport when estimating dust earth system impacts.

This study evaluates vertical aerosol profiles (backscatter βₐₑᵣ and extinction αₐₑᵣ coefficients) using ceilometer, GRASP_pac (ceilometer-sun photometer synergy), and COBALD balloon soundings across three European stations (2019 - 2020). Analyzing 4,530 profiles and 35 COBALD soundings. Forward inversion with ceilomneters exhibited the lowest deviations and variability compared with backward. This study underscores the enhanced performance of ceilometer retrievals utilizing the forward inversion in comparison to GRASP_pac. Furthemore, the findings validate the reliability of GRASP_pac for aerosol profiling emphasizing the advantages of synergistic retrieval approaches.

This paper presents a new technique for estimating the dry deposition of aerosols based on the synergy between observational data from ground-based remote sensing and in situ instruments (operated at the RADO-Bucharest ACTRIS station), Copernicus Atmosphere Monitoring Service (CAMS) products and atmospheric models. To estimate the dry deposition, black carbon was used as a proxy for aerosols. The result shown that the modeling of aerosol deposition requires also precise vertical aerosol profiles at the in situ station; the effect of medium- and long-range transport of aerosol can not be neglected when investigating the air quality using in situ measurements.

Processes on the earth-atmosphere interface influence the source-sink dynamics of airborne microplastics (MPs), yet we lack understanding and quantification. Monthly atmospheric deposition over one year (08/2024-07/2025) at four study sites located less than 700 meters apart at the Ecological-Botanical Garden at the University of Bayreuth, Germany were collected and analyzed for number, size, shape, and polymer type using micro-Fourier transform infrared spectroscopy. We evaluated the relative importance of wet and dry depositions in the scavenging of airborne MPs and explored its spatial and temporal variability.

This study examines airborne nano- and microplastics (NMPs) in an urban environment, focusing on their concentration, size distribution, and chemical composition. Using aerosol samples collected over two weeks, the current study analysed synthetic polymers in different particulate matter (PM) fractions: PM₁₀, PM_2.5 (fine microplastics), and PM_10-2.5 (coarse microplastics). Tire wear particles accounted for ~65% of total NMPs, with car tire tread as the dominant. Strong correlations were observed among fine microplastics, indicating common sources. Associations with carbonaceous species suggest shared emissions and secondary formation processes. Findings emphasize the need for extended monitoring and regulatory measures to address airborne NMP pollution.

Micro- and nano-plastics (MNPs) are emerging pollutants due to their widespread presence, however, identifying airborne MNPs is challenging due to their small size. Mechanical recycling, essential for a circular economy, can generate MNPs during energy-intensive processes like shredding and washing. Understanding MNP formation in recycling facilities is crucial for emission reduction strategies. This study tracked polypropylene (PP) emissions during recycling, using real-time and offline particulate matter sampling methods. Results showed increased airborne particles during shredding and significant PP emissions during washing. These findings can help develop protocols for monitoring and reducing airborne MNPs in recycling processes.

Inhalation is the primary route of exposure to micro- and nanoplastics (MNP) for workers, especially in workplaces involving plastic materials. Indoor MNP concentrations can be much higher than outdoors, but limited data and lack of standard methods hinder exposure assessment. The INAIL BRiC CELLOPHAN project aims to develop multi-technique sampling and analytical methods to characterize airborne MNP in the particulate matter (PM) of indoor workplaces. Three plants were investigated (a water bottling plant, a tyre fixing/car repair shop and a textile factory) by different co-located samplers (PM, VOC) and direct-reading instruments. First-year results are presented and discussed in this contribution

This study explores whether microplastics, including polypropylene, polyethylene, polyethylene terephthalate, and tire wear particles can influence cloud formation by promoting ice formation. Laboratory experiments show that some microplastics can act as ice-nucleating particles and initiate freezing in mimicked cloud droplets at higher temperatures than the water background. Simulated atmospheric aging had either no effect or decreased the freezing temperatures. These findings suggest that microplastics may impact cloud freezing processes if present in high concentrations. In addition, their atmospheric lifetime may be impacted by ice nucleation followed by precipitation, with implications for their transport pathways.

Microplastics (MPs) have been detected in various environmental, as well as biological, contexts and their presence has attracted the attention of the scientific community, which has classified them as new emerging contaminants. Airborne MPs are a relatively new topic and research has to largely focus on indoor environments, as most people, on average, spend around 90% of their time in homes and workplaces.

Consequently, the aim of this innovative study, performed within the BRIC ID-14 CELLOPHAN project, is to investigate the exposure levels of MPs in workplaces, specifically by characterizing them using a combination of spectroscopic and microscopic techniques.

The current study aims to integrate a methodology to quantify the translocation of UFPs from the nose to the olfactory (OLF) region and estimate the OLF deposition combined with an analysis of using different metrics for particles with an aerodynamic diameter smaller than 0.1 μm: mass (PM_0.1), number (PN_0.1), and surface concentration (PS_0.1). Simulations examined the source-specific impact from exposure to four distinct common urban sources: nucleation event, heating emissions, traffic emissions, and background levels. The estimation of the regional dose, clearance, and retention of UFPs in the HRT was also evaluated whilst the number of deposited particles per surface area/cell was estimated.

This study presents a novel methodology for measuring aerosol inhalation dose in enclosed environments using human participants while ensuring safety. Magnesium aerosols serve as tracers, collected via inhaler filters and analyzed with ICP-MS to quantify inhaled dose. Experiments were conducted under three airflow conditions: no ventilation, forced ventilation, and forced ventilation with air filtration. Results showed that inhalation dose decreased with distance and was significantly reduced under forced ventilation. Protection factors indicated that air filtration was most effective at short distances. This approach provides a practical and accurate means to assess aerosol exposure,.

The inhalation of virus-laden microdroplets, emitted through breathing or talking, is a mode of transmission of airborne diseases that is difficult to control, especially since the mechanisms of virus persistence in aerosols are not yet fully understood. The aim of this research is to study the evaporation dynamics of virus-laden respiratory microdroplets, with a particular focus on the impact of their composition on this process. We present initial results on the study of real saliva aerosols, highlighting the need to investigate pathogen survival in biological matrices rather than in synthetic media, which have traditionally been used in the literature.

The present study aims to assess how the OP of traffic-originated UPFs is linked to adverse effects in vitro and in vivo. In vitro, assessment includes cell exposures utilising a thermophoresis-based air-liquid interface (ALI) system and submerged exposures with traffic exhaust emissions. For in vivo assessment C57BL/6 mice were exposed to fresh and atmospheric aged traffic emissions from gasoline and diesel vehicles. The present study provides new, important insights into the cellular mechanisms induced by different air pollutants and how the OP of the UFPs is connected to those.

We measured the OP of aerosols derived from laboratory-generated air masses using various acellular methods after sampling on filters. These experiments were conducted on the PolluRisk platform, which enables preclinical models to be exposed for several days to simulated urban atmospheres. This platform includes an atmospheric chamber capable of generating realistic air masses, which are then transferred to exposure systems housing preclinical models. Additionally, a suite of analytical instruments is connected to these systems to characterize the physicochemical properties of the simulated air masses (gases and particles).

This study found that 6PPD was not cytotoxic at concentrations up to 10 μg/mL but was able to cause oxidative stress by glutathione (GSH) depletion (P<0.05) and cause DNA damage (P<0.05) after 24 hours exposure. The presence of N-acetyl-L-cysteine (NAC), a GSH precursor, mitigated both GSH depletion and DNA damage.

Wildfire events present a rising frequency in recent years, especially in warm climate regions. During such events, the generated fire plume contains a mixture chemical species, driving the chemical processing during the initial and aging stage. Organic aerosols comprise a large portion of the available species and their fate is primarily determined by two competing regimes. In this work we evaluate the conditions of prevalence of each regime. The balance of these two regimes is associated with the black and brown carbon levels; thus, the differentiation of the chemical reactions in the center and at the edges of the plume.

Organic photosensitizers from biomass burning can generate oxidants, facilitating the conversion of precursors into secondary aerosols. Chloride ions mix with photosensitizers in biomass burning particles, influencing aerosol oxidative potential. Using SO₂ oxidation to sulfate as an indicator, we found NH₄Cl + glyoxal particles produced sulfate 4–5 times faster than NaCl + glyoxal, especially at low humidity. Adding imidazole-2-carboxaldehyde (IC) increased sulfate production 73-fold compared to NH₄Cl alone. Kinetic analysis revealed chloride ions react with ³IC* at rates ~1000 times higher than in bulk solutions, highlighting the synergistic role of chlorine chemistry and photosensitization in atmospheric oxidation.

Reactive nitrogen has previously been found relevant in new particle formation and growth events, but specific mechanisms are not yet fully understood. The research consortium of CAINA (Cloud-Aerosol Interactions in a Nitrogen dominated Atmosphere) aims to gain new insights into these important interactions. We will present first results of aerosol and gas composition measurements that have started in a nitrogen rich environment in central Netherlands. A MARGA, ACSM and chemiluminescence NO_y detector are used to investigate nitrogen speciation across the gas and aerosol phase. The studied mechanisms are informed by thermodynamic equilibrium models (e.g. ISORROPIA2 and E-AIM).

A regional air quality model system (RAQMS) was developed by incorporating an aqueous reaction mechanism for secondary organic aerosol (SOA) formation and primary semi-volatile (SVOC) and intermediate volatile organic compounds (IVOC) precursors to investigate various chemical pathways for SOA formation in the Beijing-Tianjin-Hebei (BTH) region in wintertime. The average contributions from various precursors or chemical pathways to SOA formation during the study period were estimated, in which AVOCs (anthropogenic VOCs), SVOCs, IVOCs, BVOCs (biogenic VOCs), GLY and MGLY contributed 38.4%, 24.9%, 28.4%, 0.2% and 8.1% of SOA mass concentration, respectively, in the BTH region.

This work quantifies the contribution of local versus regional PM sources in Cypriot cities by applying two source apportionment methods namely the “Lenschow approach” and Positive Matrix Factorization (PMF) to a comprehensive filter-based PM_2.5 chemical composition dataset collected at multisite network consisting of one urban traffic site (NICTRA) and two urban background (NICRES and LIMRES) located within the two largest cities of Cyprus (Nicosia and Limassol), along with one regional background (AMX).The robustness of our conclusions on local versus regional source contributions is demonstrated by strong agreement between the two techniques.

Black Carbon (BC) is a key air pollutant affecting air quality, climate, and public health. This study analyzes over five years of BC measurements in Berlin using Aethalometer AE33 data, alongside PM₂.₅, PM₁₀, NOx, and CO concentrations to assess source contributions. Traffic-related BC will be estimated using NOx and CO correlations, while biomass burning influences will be evaluated through seasonal trends and, where possible, levoglucosan or Elemental Carbon/Organic Carbon validation. Seasonal, annual, and diurnal variations will be examined, contributing to the Net4Cities initiative. Findings will inform air quality policies, particularly in quantifying fossil fuel vs. non-traffic BC contributions.

Biomass burning is a major source of atmospheric aerosols, impacting air quality and climate. This study examines the isotopic composition (δ¹³C) of aerosols from various wood species and coal under controlled and uncontrolled combustion conditions. Two experimental setups were used: one simulating domestic heating in Lithuania and the other in a controlled laboratory environment. Biomass materials (18 types) and coal were combusted, and aerosol samples were collected using a high-flow sampler. δ¹³C values varied between −24‰ to −30‰ for uncontrolled and −22‰ to −29‰ for controlled conditions. The findings highlight the influence of combustion conditions on aerosol formation and composition.

Quintero and Puchuncaví are two coastal cities in Chile currently recognized as part of the country's "sacrifice zones" due to frequent air pollution episodes caused by industrial emissions. A key challenge is identifying the spatiotemporal distribution of PM_2.5 and SO₂ near these sources. We developed a new methodology for source apportionment of industrial emissions using a fuzzy clustering technique to determine the contributions of PM_2.5 and SO₂ concentrations from industrial complexes in these cities. This approach allows us to isolate industrial impacts from other sources in the study areas, such as traffic and residential emissions.

Phosphorus (P) is crucial for ecosystems, cycling through land, ocean, and atmosphere. In the eastern Mediterranean, P limits marine productivity, with atmospheric deposition as a key source. This study analyzed PM2.5 (Athens) and PM10 (Heraklion) samples for total and inorganic P, bioaerosol proxies, and chemical components. Results showed peak total P in spring, correlating with bioaerosols. Positive Matrix Factorization identified bioaerosols (31%) as major P sources, followed by anthropogenic emissions (28%) and Saharan dust (19%). These findings highlight the significant role of bioaerosols in atmospheric P cycling, emphasizing their importance in marine nutrient supply.

An aerosol is a suspension of a liquid or solid particles suspended in a gas. Aerosols are a key contributor to environmental issues such as global warming, poor air quality and health. Depending on their nature, aerosols are divided into natural and artificial. Natural aerosols are formed under the influence of natural forces

The aim of this study was to determine the sources of aerosol particles using positive matrix factorization in an urban background environment. Measurements were performed from January 2 to December 21, 2019 at the urban background site located at the Vilnius.

Air pollution in Sarajevo, Bosnia and Herzegovina, is exacerbated by wintertime temperature inversions and solid fuel combustion, leading to PM2.5 levels comparable to those in Asian megacities. To identify pollution sources, high-resolution mobile and stationary measurements were conducted in January 2023 as part of the SAAERO project. Using Positive Matrix Factorization (PMF), five organic aerosol factors were identified, with oxygenated organic aerosol (OOA) dominating overall. Residential wood burning and cooking were key contributors in different urban areas. These findings provide crucial insights for targeted air quality mitigation strategies in South-Eastern Europe.

Submicron particulate matter (PM₁) impact health, climate, and ecosystems, with Organic Aerosol (OA) being a key component. OA is either directly emitted (POA) or formed through atmospheric processes (SOA), undergoing ageing during transport. Time-of-Flight- (ToF) and Quadrupole- (Q) Aerosol Chemical Speciation Monitors (ACSM) have been measured non-refractory PM₁ (NR-PM₁) since August 2024, in Bologna (urban) and at Mt. Cimone (remote). Results show OA dominates NR-PM1, with SO₄ more abundant at Mt. Cimone and NO₃ at Bologna. POA is observed in the lower Po Valley but absent at Mt. Cimone, indicating significant OA ageing, influenced by Planetary Boundary Layer dynamics.

Crop residue burning severely impacts air quality and health in India, despite regulations. This study measures black carbon (BC) at a rural stubble-burning site in Punjab and applies source apportionment techniques. The Aethalometer Model (AM), though widely used, identifies only two sources, limiting accuracy. To improve analysis, the Positive Matrix Factorization (PMF) model was also used. BC concentrations ranged from 1.45 to 85.0 µg/m³, averaging 12.6 µg/m³. AM estimated 48.5% BC from biomass burning and 51.5% from fossil fuels, while PMF identified five sources. The study found an average Absorption Ångström Exponent (AAE) of 1.7 ± 0.3.

Air pollution in Lahti is influenced by transboundary transport from Eastern Europe and Russia. This study applied the FLEXPART-SOSAA model to assess pollutant transport and the role of large-scale weather patterns. Results show significant contributions of sulphates, black carbon, and organic aerosols, with seasonal variations driven by coal combustion, biomass burning, and meteorological conditions. Cyclones enhance transport, while anticyclones cause stagnation. Model results align with ground-based observations, highlighting the need for international cooperation and adaptive strategies for air quality management.

This study examines black carbon (BC) sources and aerosol optical properties in Vilnius and Warsaw during the warm (2022) and cold (2022/23) seasons. Aethalometers and Nephelometers were used to investigate BC source contirbution and optical properties, while the FLEXPART model was used to distinguish local and transported BC. Results showed similar BC source distribution in summer but increased coal burning in Warsaw during winter. Optical classification indicated higher contribution of BC-BrC mixtures in winter, though small BC-dominated particles prevailed year-round. Long-range transport significantly influenced BC levels, especially in winter, highlighting its role in urban BC dynamics in Poland and Lithuania.

Light-absorbing carbon (LAC) consisting of black carbon (BC) and brown carbon (BrC) are key compoents of PM2.5 and poses risks to climate, visibility, and human health. LAC was mesured at 6 sites in Lagos Nigeria from 2020 to 2021 using filter and continuous methods. Filters were analysed for LAC with a Multiwavelength Absorption Black Carbon Instrument (MABI) at seven wavelengths (405 nm, 465 nm, 525 nm, 639 nm, 870 nm, 940 nm and 1050 nm) and for EC with a Sunset thermal-optical analyzer. Aethlab MA350s were operated at each site. Differences among sites and measurements will be presented.

The optical properties of aerosol emitted during cooking in rural households in Rwanda were investigated. Participants used traditional cooking methods and improved cookstoves. Aerosol mass concentrations were monitored using portable light absorption photometers. Filter PM10 samples were collected and analysed to determine elemental, organic (OC), and total carbon concentrations. During the use of the stoves, the total absorption decreased by ~50-70% compared with traditional cooking. The largest reductions occurred in the UV due to a significant difference in OC between both methods. The change resulted in different Absorption Ångström Exponent (AAE, traditional cooking = 2,4, new stove = 1,4).

This study investigates the optical and aerodynamic properties of solid aerosol aggregates in the context of stratospheric aerosol injection (SAI) for solar radiation management. Through numerical simulations and laboratory experiments, it quantifies the impact of particle coagulation on light scattering and atmospheric residence time, both of which collectively determine the radiative forcing potential of injected aerosols.

BC is emitted primarily from the incomplete combustion of fossil fuels, biofuels, and biomass burning, therefore, can be classified into two subfractions: fossil fuel (BCff) and biomass burning (BCbb). BC is formally defined as a refractory light-absorbing substance composed of aggregated carbon spherules.

San Luis Potosi City is located in central Mexico and is characterized by a huge automotive industry, funding industry, and mining sector.

This study presents an evaluation of BC measured by an AE33 Aethalometer, from three different zones and years in San Luis Potosi City, with different characteristics and emission sources.

This study examines the contribution of PAHs to Brown Carbon (BrC) light absorption at a semi-urban site in Jorhat, India. Using laser reflectance data and the Minimum R² approach, BrC absorption was determined and apportioned into primary and secondary BrC. PAHs contributed 0.8% to BrC absorption, with high molecular weight PAHs dominating (98.6%). Benzo(g,h,i)perylene was the largest contributor (41.2%). PAH absorption correlated strongly (0.84) with primary BrC but weakly with secondary BrC, highlighting its origin from direct emissions and its significant role in BrC radiative forcing and atmospheric impact.

Atmospheric aerosol chemistry is crucial to assess and understand the role of aerosols in controlling the surface water biogeochemical processes. In this context, a cruise-based study is undertaken during northeast monsoon (NE), and aerosol samples were collected for the analyses of their chemical composition in the Arabian Sea. This comprehensive analysis of aerosol composition in the Arabian Sea provides valuable insights into the sources and transformation processes of marine aerosols, emphasizing the influence of continental outflows and secondary aerosol formation. These findings contribute towards the better quantification of aerosols, which plays an important role in understanding the surface water biogeochemistry.

This study, part of APEAL, uniquely examines seasonal and spatial variations in PM2.5 chemical composition across four Indian cities. PM2.5 levels were highest in Delhi, especially in winter, exceeding other cities by up to 87%. Overall, major contributors to PM2.5 levels were WSII, OC, and EC. WSII, dominated by sulfate and nitrate, peaked in winter, while summer fractions featured sodium and phosphate. SOC was highest in Delhi (86%), indicating strong photochemical activity, while WSM, mainly zinc, peaked in Mumbai. This spatial and seasonal variability in chemical composition can explain varying impacts rather than PM mass concentration.

The oxidation of biogenic volatile organic compounds (BVOCs), such as α-pinene, plays a key role in secondary organic aerosol (SOA) formation, particularly in nitrogen-rich atmospheres like the Netherlands. This study integrates AIDA cloud chamber experiments with the F0AM box model to investigate the multiphase chemistry of α-pinene oxidation products. By varying relative humidity and seed composition, we assess their impact on SOA growth and organic nitrogen species formation. Our results improve the mechanistic understanding of gas-aqueous-particle partitioning, enhancing SOA representation in cloud-resolving models and contributing to better predictions of aerosol evolution in regional and global atmospheric models.

This study presents chemical speciation of the gas and the particle phases during the uptake of gaseous glyoxal on deliquesced AS seed particles (RH ≥ 80 %) in the CESAM chamber.
Fast reactive uptake of gaseous glyoxal on AS particles was observed, source apportionment analysis through positive matrix factorization led to the identification and quantification of three dominant processes: glyoxal hydration, fast aging and photochemistry. Individual products, e.g. imidazole-2-carboxaldehyde, were formed within minutes in the chamber. A detailed mechanism of glyoxal reactive uptake will be proposed.

A water droplet in air acts as a complex chemical reactor, where various chemical species interact with each other, and many reactions can occur, such as acid-base reactions, photolysis, metal hydrolysis, and complexation. Modelling the chemical species in these droplets helps better understand environmental processes. These processes are influenced by the type and concentration of specific chemical species. Speciation models for water-soluble components of PM10 have been developed. The results highlight the importance of the interaction between Fe and oxalate. More detailed investigation of this interaction was conducted by modeling different conditions to assess the photochemical activity of these systems.

Condensable vapors are precursors of Secondary organic aerosols (SOA). Their improved detection has led to massive progress in the understanding of atmospheric processes, but the large variety of instruments and techniques limits the comparability of the results. In this study, ten NO₃-CI-ToFMS instruments took part in an intercomparison workshop at a simulation chamber setup. A unified inlet system was designed to improve the comparability. A series of experiments were performed parallel in both chambers, including gas mixtures of analytical standards, α-pinene oxidation under various conditions and sulfuric acid formation from OH oxidation. Observed differences emphasize the need for further investigation.

Fine particulate matter is a key air quality indicator influenced by interactions with other pollutants and meteorological conditions. In this regard current study focuses on PM2.5 and associated BC and PAH concentrations at an urban background site in Sofia, where three samplings were carried out during February-March 2022, October-November 2022 and February-March 2023. BC concentrations were analyzed using Multi-wavelength Absorption Black Carbon Instrument, while 19 PAH compounds in PM2.5 were quantified via GC-MS/MS. Present study analyzes correlations between PM2.5, BC, PAHs and other pollutants (PM10, NO2, CO, Benzene) using data from Sofia-Mladost (EEA) and assesses the impact of meteorological factors.

Hydroperoxy radical (HO2) is key in NO to NO2 oxidation, contributing to tropospheric O3 formation. While HO2 uptake on wet aerosols is efficient, its impact on O3 remains unclear. Model simulations of a severe O3 pollution episode in the North China Plain (NCP) in 2018 showed that HO2 heterogeneous loss reduced daytime HO2 and MDA8 O3 concentrations by 5% and 1%, respectively. However, decreased HO2 uptake due to reduced emissions from 2013 to 2018 only contributed to a 5% increase in MDA8 O3, indicating it is not a major driver of O3 trends in the NCP.

This study aims to characterize the key radicals and oxidants during PM_2.5 and O₃ episodic and non-episodic days in a Taiwan urban area using a photochemical box model with field constraints. The OH was the dominant radical, peaking at noon and followed by HO₂ and RO₂, whereas the NO₃ peaked in the evening. The production of OH was mainly driven by the HOx cycling between HO₂ and NO, whereas the major loss of OH was due to its reaction with VOCs. Nighttime chemistry of NO₃ and N₂O₅ hydrolysis were implicated in elevated PM_2.5 in the following morning hours.

Biomass-burning organic aerosol(s) (BBOA) are rich in brown carbon (BrC), which significantly absorbs solar irradiation and potentially accelerates global warming. Despite its importance, the multiphase photochemistry of BBOA remains poorly understood. In this study, we explored the photochemical reactivity of BBOA particles in multiphase S(IV) oxidation to sulfate. We found that sulfate formation in BBOA particles is predominantly driven by photosensitization involving the triplet excited states (³BBOA^*). Our results highlight that the chemistry of ³BBOA^* in particles can greatly contribute to the formation of sulfate. Photosensitization of BBOA will likely become increasingly crucial due to the intensified global wildfires.

Peroxide species are key oxidants in shaping the atmospheric oxidative capacity, yet their formation pathways remain elusive under high-NO_x conditions, where classical gas-phase mechanisms are suppressed. Herein, we report an underappreciated ‘in-particle’ peroxide formation pathway driven by photosensitization reactions in biomass burning organic aerosol (BBOA). This mechanism remains highly efficient even in polluted, high-NO_x environments, leading to orders-of-magnitude increase in particulate H₂O₂ concentrations under sunlight—far exceeding levels expected from gas-phase partitioning. These new findings suggest that intensifying wildfires in our warming world, beyond their primary emissions, may significantly reshape atmospheric oxidation chemistry and exacerbate air quality degradation.

Recent research challenges the assumption that ammonium sulfate (AS) aerosols are photochemically inert. While prior studies used dilute solutions, aerosol liquid water (ALW) contains high ionic strength AS, allowing for the formation of reactive sulfate radicals (SO₄•⁻) under troposhpehric light. Wildfire-emitted chromophores, increasingly common due to climate change, significantly enhanced SO₄•⁻ radical production when added to these AS solutions. To determine the production yield, the radicals were trapped with an organic compound to form organosulfates, and tracked via liquid chromatography coupled with high-resolution mass spectrometry. The findings reveal important implications for atmospheric chemistry, climate models, aerosol-cloud interactions, and health impacts.

This study employs a numerical modeling approach to analyze pollutant emissions from a combustion chamber and their transformation into aerosols in urban environments. The first phase focuses on optimizing fuel injection control to reduce emissions and improve efficiency, revealing that an increasing oscillatory injection pattern enhances power output while enabling waste heat recovery. The second phase models pollutant dispersion and chemical transformation in street canyons and open areas using CFD and atmospheric chemistry simulations. The findings offer insights into the impact of fuel injection strategies, urban geometry, and meteorological conditions on air quality, supporting better emission control and mitigation policies.

This work presents the results produced within the framework of The Puglia Regional Air Quality Plan. The reconstruction of PM10 concentrations across the entire regional territory, for a specific emission scenario, was carried out using the modelling system implemented at ARPA Puglia. The emission database was reconstructed for the year 2019 using the INEMAR system. The model performance evaluation was conducted using the DELTA TOOL software, by comparing the modelled PM10 data with the measured data from the 61 monitoring stations of the regional air quality network, taking into account the contribution of Saharan dust.

Urban air quality significantly affects public health, with traffic emissions influenced by urban structures. This study investigates how a noise barrier affects traffic aerosol movement using the parallelized large eddy simulation model PALM. Simulations use real-world topographic and also meteorological data to assess conditions with wind flowing perpendicular to the highway. By comparing scenarios with and without the barrier, and validating results with field measurements, the study evaluates its impact on total particle concentrations.

Here, state-of-the-art real time and time integrated instrumentation is used to characterize the physicochemical properties and radiative effects of wildfire particulate matter (WFPM) reaching the highly populated metropolitan areas of New Jersey/ New York during the extreme wildfire incident of summer 2023. The WFPM direct radiative forcing of -352.4 W/m² derived here based on the light absorption and scattering measured at the peak of this incident explains the observed temperature reduction of about 3 K. Such negative radiative forcings may limit natural ventilation of megacities, increase the residence time of WFPM and other background air pollutants, exacerbating public health risks.

Mexico is number 13 on the list of countries with the largest volumes of CO₂ emissions in year 2013. Nevertheless, there are not enough official measurements of BC, especially in most medium-sized cities. Peralta et al. (2019) recompiled all the BC studies measured in Mexico, and pretended to establish a BC Network, but just a few state governments were interested. This study added information from 5 different monitoring sites with different characteristics measured by an AE33 Aethalometer, to have a better understanding of this pollutant to develop mitigation and adaptation strategies, reduce emission precursor sources, and risks in the population.

Aerosol particles cause aircraft engine deterioration, adversely affecting flight safety and maintenance costs. The present paper aims to contribute to refining estimates of the amount of aerosols ingested by engines. Therefore discrepancies in model outputs and atmospheric measurements are identified. This is done by comparing atmospheric composition models with in-situ measurements of aerosol particles, which were performed with the research drone ALADINA downwind of the airport Berlin-Brandenburg. The research shows that the aviation community needs observations in airport proximity to obtain more precise estimates of the quantities of ingested contamination.

The present work will focus on outdoor air pollution and examines the various factors that contribute to the concentration of PM_2.5 in ambient air in Cotonou, Benin. Ambient air quality was monitored over the period from January to May 2024. Statistical analysis tools were used to identify and quantify the contribution of sources to the concentration of PM_2.5 in ambient air in Cotonou.

Results show that exceedances of ambient PM_2.5 concentration occur mainly during the dry season, when the harmattan wind is active. A maximal average daily concentration of 166 µg/m³ was recorded, whereas the WHO recommendation is 15 µg/m³.

Air pollution is a major health risk, with PM_2.5 exposure causing 253,000 premature deaths in the EU in 2021. Urbanization alters air pollution distribution by increasing built-up areas and reducing green spaces. This study examines how 2D/3D urban form affects PM_2.5 in Vilnius, Lithuania, using Spatial Random Forest machine learning. Key factors influencing PM_2.5 include built-up volume (BU-Vol), percentage of landscape (PLAND), and largest patch index (LPI), while edge density (ED) is least important. Findings enhance understanding of urban form’s impact on air quality, aiding pollution control efforts.

Ultrafine aerosol particles (UFP) impose significant health risks, especially in the vicinity of airports due to high exposure of emissions. To obtain a profound understanding of the vertical distribution of UFP in the atmospheric boundary layer, the research drone ALADINA was used to measure aerosol particles in the size of 4-19 nm (N_4-19) around Frankfurt Airport in October 2024. The results indicate a pronounced appearance of N_4-19 close to ground, when air masses originate from the airport plume. In addition, peaks of N_4-19 occur in a vertically concentrated altitude of 200-400 m, suggesting horizontal transport during aircraft approach.

In the Mediterranean, Saharan dust transport increases PM10 levels, often exceeding EU limits and impacting human health. Recent years have seen more frequent and intense intrusions, likely due to climate change. The LaMMA Consortium applied a weather classification method to identify circulation patterns linked to these events. Data from the AirQino network helped track PM10 and PM2.5 plumes in space and time. Analyses from 2018-2023 reveal both direct and complex dust transport paths. Chemical analyses of PM10 samples in Tuscany confirmed the desert origin using techniques like ion chromatography, PIXE, and ICP-AES.

We use the regional atmospheric model WRF and the Hybrid Single-Particle Lagrangian Integrated Trajectories model to diagnose the contribution of Saharan dust to the northwest region of Spain. We find that synoptic conditions correspond to an anomalous cut-off low whose center initially sits in front of the Iberian Peninsula and rapidly migrates southwards over northwest Africa and Morocco, exposing air to the central dust source in the region. These dynamic conditions are apt for a strong meridional advection of aerosol, which limits the action of scavenging processes and renders a substantial mass of aerosol deposition in NW Spain.

An innovative instrument to quantify multple properties of aerosol particles has been developed that integrates technology that images at high resolution, extracts the complex refractive index from spherical particles, identifies organic and bioaerosols from the fluorescence signatures and measures the absorption cross section with thermal analysis. The Spectroscopic Multiparameter Particle Analyzer (SMPA) is the results of years of development at DMT of a suite of ground based and airborne instrument, i.e. the CAPS, WIBS, SP2 and AFN that have been well characterized by users worldwide. Selected featurs from the instruments have now been integrated into a single system, the SMPA.

The LIFE SIRIUS project enhances air quality governance in urban areas through integrated assessment methods. In Rome, it evaluated Air Quality Plans, emission scenarios, and mitigation measures. Using a high-resolution dispersion model, it projected air quality for 2030 under "do nothing" (CLE2030) and "with measures" (CLE2030+AQP) scenarios. Findings indicate NO₂ reductions up to 13 µg/m³, PM_2.5 drops up to 13 µg/m³, and consistent PM₁₀ improvements. Measures like sustainable transport and renewable energy incentives proved effective. The study highlights the need for coordinated policies, robust emission inventories, and advanced modelling to meet air quality targets and mitigate health risks.

This study compares two chemical transport models – EMEP4PL (4 km x 4 km resolution) and downscaling uEMEP (1 km ×1 km, 500 m × 500 m, and 100 m × 100 m resolutions) – using daily averages of PM2.5, NO₂, and O₃ in 2022. We examined seasonal variability, station/area type effects. The uEMEP model demonstrated significant performance improvements compared to EMEP4PL. The highest accuracy was achieved at 500 m × 500 m resolution. The uEMEP model outperformed EMEP4PL, with improvements at rural stations and weaker performance at urban traffic sites. Seasonal analysis revealed challenges.

The North China Plain (NCP) has rapid urbanization, with urban areas increasing from 1.78% in 2000 to 6.70% in 2015. Urban expansion impacts air quality through changes in meteorology and physicochemical processes. WRF-Chem simulations show urbanization raises near-surface temperature by 0.2℃, boundary layer height by 1.6%, and humidity by 0.4%. O3 increases by 2.2%, while PM2.5 decreases by 2.4% overall and 8.9% in urban areas. NO2, SO2, and CO also decline. Despite higher emissions, urban expansion reduces particulate pollution in cities.

The study assesses the microscale impact of particulate matter emissions from a large steel plant in Taranto, Italy, using Lagrangian particle modeling. The aim is to reconstruct exposure at a microscale level, considering the influence of urban structures and recently built park roofs on pollutant dispersion. Simulations were conducted with the PMSS modeling suite over an 8 km × 8 km domain with a 5 m resolution, divided into 25 communicating tiles to speed up a parallel computation which was performed on a the RECAS HPC Data Center. The abstract presents the modeling setup and preliminary results of the study.

This study presents a preliminary assessment of aerosol concentrations at the Col Margherita Observatory (2543 m a.s.l.). Data from June 12, 2023, to August 20, 2024, showed a seasonal pattern, with maximum concentrations in summer and late summer, and minimum values in winter. Diurnal trends were generally weak, but particles tended to peak at night and drop during the day, opposite to planetary boundary layer height. These findings suggest distinct sources and processes for different particle sizes and offer insight into aerosol transport in the Dolomites. Further analysis will include LIDAR data from Passo Valles.

Larger than expected decreases in PM_2.5 have been observed recently across the UK. This work utilises the AURN and complementary networks to investigate the potential drivers of these recent reductions. The largest reductions of aerosol components were ammonium and nitrate during spring, with larger decreases observed at more southerly sites. Overall, the European source of PM_2.5 appears to be weakening during spring, driving reductions in PM_2.5 concentrations in the UK. This analysis highlights a complex air quality policy issue. The UK can only control a certain fraction of the PM_2.5 concentrations, with the controllable fraction varying across the UK.

Secondary Organic Aerosols (SOAs) are formed from the oxidation of Volatile Organic Compounds (VOCs). They present complex chemical compositions. To assess the molecular characterization of them, the Electrospray Ionization – Liquid Chromatography – Quadrupole Time of Flight – Tandem Mass Spectrometry was implemented with simulation chambers/flow tubes for different VOCs precursors emitted by various sources: biomass combustion (furans, methoxyphenols), vegetation (terpenes) and transport (aromatics). These studies demonstrate the usefulness and effectiveness of the technique to characterize oxidation products, oligomers, Highly Oxygenated Organic Molecules... This work is useful for SOA formation understanding, identification of markers to trace sources and toxicological studies.

This study investigates the PM10 (particulate matter of diameter smaller than 10 μm) organic aerosol fingerprints in an urban and a suburban site in Heraklion, Crete, during winter 2024. Liquid chromatography coupled with electrospray ionization Orbitrap mass spectrometry was used to analyze 48 PM10 aerosol filter samples in both positive and negative full MS modes. Principal component analysis revealed a clear separation between urban and suburban samples for positive ion mode features. The majority of significant urban features in positive mode correlated with black carbon and predominantly consisted of relatively high volatility molecules with low O:C ratios indicating fresh emissions.

Four indoor chemical characterisation campaigns were conducted in five Italian hospitals. Measurements were performed before the peak of SARS-CoV2 (autumn 2019), during (spring 2021) and after the lifting of the pandemic restrictions (winter 2022 and 2023). Deposition dust (DD) and its comparison with atmospheric particulate matter (PM) were analysed. In this study, PM samples were collected using an air conditioning filter, which can represent indoor particulate matter. The air conditioning filter has a good effect on particle retention and is contaminated by ultrafine particles, which can be resuspended and follow the air conditioning back into the indoor air.

While vehicular emissions are highly regulated, significant uncertainty remains during cold starts as well as their potential to form secondary organic aerosol. To address this gap, a measurement campaign was conducted in an underground parking garage in Patras, Greece, providing a controlled environment to study light-duty vehicular emissions. An oxidative flow reactor was placed in front of a PTR-CHARON-ToF-MS and an AMS to simulate aging of vehicular emissions over timescales ranging from hours to days, allowing characterization of both fresh and aged volatile organic compounds (VOCs) and the fresh and aged organic aerosol.

The chemical composition of first-step oxidation products is measured and identified by elemental composition, but molecular structures are only estimated by modeling. Here we add additional measured information about the atmospheric nucleating clusters by measuring the stability of clusters of highly oxygenated organic molecules from alpha-pinene ozonolysis and sulphuric acid oxidation. We use a differential mobility analyzer together with an electrospray and mass spectrometer to generate ions with known composition (ammoniumhalides), fragment them in mass spectrometer and apply the obtained fragmentation energy to unknown sample from CLOUD chamber.

Biomass burning impacts climate, air quality, and health through aerosol emissions that undergo oxidation under day and night conditions. This study, based on experiments at the EUPHORE simulation chambers, explores daytime photooxidation of emissions, driven by OH radicals, and nighttime aging, dominated by nitrate radicals. Using advanced instrumentation (API-ToF-CIMS+FIGAERO), key compounds found in the particle phase as well as chemical families are identified for each oxidation condition tested. The findings highlight how oxidation processes influence aerosol composition and optical properties, emphasizing their role in climate and air quality.

Aerosol particles influence cloud formation, precipitation, radiative transfer, and air quality, impacting meteorological predictions. From June 15 to July 26, 2023, aerosol measurements were conducted at Mt. Feldberg (1500 masl) in the Black Forest, Germany, using advanced sensors and mass spectrometers. Lidar scanning provided atmospheric structure insights. Data from the Swabian MOSES 2023 campaign showed aerosol variations linked to Saharan dust, Canadian wildfire plumes, and precipitation washout effects. High-resolution mass spectra will help identify aerosol sources for comparison with transport models. This study examines aerosol composition, sources, and their relation to meteorological conditions.

In this contribution, we introduce a new interpretable molecular descriptor, ATMOMACCS, specifically tailored to atmospheric molecules. We demonstrate its competitive performance in predicting various thermodynamic properties, such as saturation vapor pressure, vaporization enthalpy, partition coefficients, and glass-transition temperature, equaling or surpassing published results for four distinct atmospheric molecular datasets. Our molecular descriptor addresses the need for customized and accurate modeling in data-driven atmospheric science. Additionally, the descriptor’s inherent interpretability and strong performance in thermodynamic property prediction, using machine learning, show promise for further research in molecular-level atmospheric science.

In this work, we exposed ambient PM_2.5 samples to ammonia (NH₃) saturated air in order to identify compounds affected by atmospheric NH3 concentrations. We investigated the molecular composition of the samples after 72 hours of exposure to NH₃, water and synthetic air using HPLC-HRMS. The results show an increase in N-containing compounds and in light-absorbance.

Concentrations of carbonaceous components (OC and EC) and increased proportions of levoglucosan and terephthalic acid (TPA), particularly at night. These components are by-products of coal and waste combustion processes, indicating that ultrafine particles formed from combustion activities possess higher toxic chemical characteristics and exhibit prolonged atmospheric persistence. Additionally, the toxicity equivalency factor (TEF) evaluation of PAHs revealed that PM1.0 posed greater carcinogenic and mutagenic risks compared to PM2.5. DTT-OP analysis also indicated that PM1.0 exhibited higher oxidative potential per mass unit. These findings suggest that current policies regulating only ambient PM concentrations are insufficient and highlight the necessity for separat

Understanding the chemical composition of organic aerosol (OA) and its gaseous precursors is crucial for assessing secondary organic aerosol formation and potential health effects to exposed population. A study in an urban background site in Athens investigated the chemical composition of OA and organic gaseous species, with the use of a Proton Transfer Reaction Mass Spectrometer (PTR-TOF-MS), with simultaneous collection of sorbent tube samples analyzed through gas chromatography (GC-MS). Results were compared to corresponding measurements of the previous year at an urban location in Athens and different compounds were related to sources apportioned through positive matrix factorization (PMF).

The oxidative potential normalized to QDTT-OP for PM2.5 showed a significant correlation with key emission sources, particularly EC and Pb, likely due to incomplete combustion processes. Effectively managing these emissions is essential for mitigating health risks associated with air pollution. This study provides valuable insights for developing strategies to improve air quality and public health in areas surrounding industrial complexes.

The study concludes that the oxidative potential of PM2.5 originating from agricultural activities is elevated due to biomass burning, which could potentially increase human health risks. Moreover, the findings provide insight into the emission characteristics of air pollutants according to differences in agricultural practices between rice and dry field farming. By understanding the emission patterns based on the timing of agricultural activities and the characteristics of cultivated crops, this study offers valuable data for predicting emission quantities.

Chlorinated VOCs, such as 1,2-dichloroethane and 1,2,4-trichlorobenzene, display transport behaviors. Their relatively consistent concentrations during long-range transport emphasize the influence of industrial activities, including coal combustion and petrochemical processes, as major sources. The prevalence of chlorinated VOCs in the Chungnam industrial area and during transportation stages further highlights their strong link with industrial emissions rather than urban traffic sources. These observations necessitate the development of integrated air quality management strategies that accommodate both local and transboundary sources of VOCs.

Nitrated polycyclic aromatic hydrocarbons (NPAH) are a group of highly toxic organic pollutants with significant carcinogenic potential. NPAH are persistent in the environment and contribute to mutagenic and genotoxic effects of pollution. This has a negative impact on human health and mortality worldwide. Their long-term continuous monitoring in the Czech Republic is practically non-existent which makes this research unique. This study maps concentration of NPAH in the air and evaluates their relation to concentration of PAH and nitrogen oxides (NOx). Year-round sampling was done in four cities. High-volume sampler equipped with PM10 sampling head inlet was used for collection.

Saccharides are vital organic compounds in atmospheric chemistry, acting as tracers for aerosol sources like biomass burning and soil resuspension. This study analyzed saccharides in aerosols from highly polluted regions: Allahabad (India) and Sosnowiec (Poland). Seasonal variations were observed, with higher anhydrosaccharide concentrations in Allahabad due to hardwood and crop residue combustion, while Sosnowiec emissions mainly came from softwood burning. Correlations among saccharides indicated biomass combustion as a major source. Additionally, contributions from soil resuspension and fungal spores were noted. Overall, aerosol saccharide composition varied by location and source, impacting atmospheric processes.

Two sampling campaigns were carried out in October 2023 and 2024 near the city of Valencia, coinciding with the period when rice straw burning is allowed. During the first campaign PM₁₀ samples were collected, while during the second campaign the sampler was equipped with a PM_2.5 inlet. A comprehensive chemical characterisation, including the analysis of levoglucosan and its isomers, was performed. Marked increases in the concentrations of anhydrosugars and other components usually emitted from biomass combustion, such as WSOC and K⁺, was observed on days impacted by biomass burning, along with increases in OC/EC, Levoglucosan/Mannosan and Levoglucosan/Galactosan ratios.

Carbonaceous aerosols (CA) present significant implications for air quality, climate as well as human health. Understanding long-term trends and variability of CA is of utmost importance for evaluating the effectiveness of air quality policies and assessing their environmental impacts. This work highlights the efforts of the National Physical laboratory (NPL), UK which manages the UK’s Particle Concentrations and Numbers (PCN) and Black Carbon (BC) air quality Network. The results from this Network highlights the significance of sustained monitoring efforts in supporting evidence-based policy development and improving our understanding of aerosol dynamics in a changing environment.

In this study, a 250 m-tall tower was used to investigate the vertical distribution of black (BC) and brown (BrC) during the traditional Burning of the Witches (BoW), the largest open-air biomass burning (OBB) experiment in Central Europe. Carbonaceous aerosol concentrations were significantly higher during the BoW, and the vertical distribution was exacerbated by the low and stable atmospheric boundary layer during the night. The enrichment of the BB smoke in BrC led to a significantly enhanced absorption Ångström exponent, more pronounced at the near-surface level which was mostly influence by local OBB smoke plumes confined within the mixing layer.

Residential wood combustion is a significant source of PM_2.5 in winter, emitting volatile and semi-volatile organic compounds that form secondary organic aerosols (SOA). Despite their environmental impact, the SOA formation mechanisms, particularly involving nitrate radicals at night, remain underexplored. This study investigates the chemical transformations of the emissions from a modern logwood stove using advanced online mass spectrometry techniques (CHARON-PTR-ToF-MS and EESI-ToF-MS). Experiments, simulating real-life heating conditions, focused on the day- (OH radicals) and nighttime (NO₃ radicals) aging of softwood and hardwood combustion. The study provides real-time molecular characterization of primary and aged emissions, offering insights into their chemical composition.

Air quality is of large concern in the city of Krakow. A comprehensive study was launched in which two PM fractions (PM1 and PM10) were sampled during 1‑year campaign, lasting from April 21, 2018 to March 19, 2019. A suite of modern analytical methods was used to characterize the chemical composition of the collected samples. The carbon isotope composition in both analysed PM fractions, combined with an isotope‑mass balance method, allowed to distinguish three main components of carbonaceous emissions in the city: (1) emissions related to combustion of hard coal, (2) emissions related to road transport, and (3) biogenic emissions.

The rural-regional background monitoring station in Ravni Kotari, Croatia, continuously monitored PM10 and PM2.5 fractions throughout 2024. Elemental carbon (EC) and organic carbon (OC) were measured using the thermal-optical method, following the EUSAAR_2 protocol and EN 16909 standard. Results showed seasonal variations in carbon fractions, with no significant differences between weekdays and weekends, except for OC and total carbon (TC). While the proportion of secondary organic carbon (SOC) was consistent across PM fractions, primary organic carbon (POC) was 2.5 times higher in PM2.5. Water-soluble organic carbon (WSOC) had a higher contribution in PM10 than PM_2.5.

The chemical composition of exhaust particles from both gasoline and diesel vehicles is complex, comprising a mixture of organic compounds and elemental carbon. In current experimental setup, three different vehicles were used. The fractional contributions of aerosols released at different thermal decomposition temperatures for emissions from one diesel and two gasoline powered vehicles during different operating conditions revealed the differences that will be presented. The isotopic composition (δ¹³C_TC​) revealed the difrences of diesel exhaust particles. Detailed chemical and isotopic analysis presented herein may contribute to the broader discourse on air quality management and the development of sustainable transportation solutions.

The INTERFERENCE project investigates the concentration levels of endocrine-disrupting compounds (phthalates, alkylphenols, and musks), PAHs, and n-alkanes in indoor and outdoor air, considering both gaseous and particulate phases. Sampling was conducted across four sites in Dunkirk, covering industrial, urban, suburban, and rural environments. Seasonal campaigns collected indoor and outdoor air samples, analyzed for target compounds, alongside resident interviews. Results highlight significant differences between sites, influenced by environmental and residential factors. The next phase involves developing an action plan with residents, elected officials, and economic stakeholders through working groups to reduce exposure to endocrine disruptors.

This research examined seasonal variations in atmospheric particulate matter (PM), organic carbon (OC), and elemental carbon (EC) at two monitoring sites in Zagreb. Samples of PM2.5 were collected throughout 2024. The industrial site showed higher mass concentrations of PM2.5, OC, and EC compared to the urban background site. Seasonal variations were noted, with significant differences in EC and OC concentrations. The highest OC concentration was observed in winter at the industrial site (42.4 µg/m³). The OC/EC ratio indicated higher secondary organic carbon (SOC) in summer at both sites.

The Arctic remains critically underrepresented in organic aerosol (OA) records, limiting our understanding of its impacts on the regional and global climate system.
This study provides a multi-seasonal characterization of OA samples collected at Gruvebadet (Ny-Ålesund, Svalbard) from 2021 to 2023. High-resolution mass spectrometry was performed on 29 offline aerosol filters, allowing us to derive key molecular parameters to assess their chemical composition and atmospheric processing. Results reveal strong seasonal variability, with oxidation patterns influenced by marine emissions, long-range transport, and Arctic Haze. These findings expand Arctic OA datasets, improving our understanding of aerosol sources and their representation in climate models.

Here, soot is produced by enclosed spray combustion of jet fuel blending with pentanol. The physicochemical characterization of the generated soot is obtained using real-time and time-integrated sampling instrumentation. Increasing the pentanol content decreases the mass concentration up to 70 %, as well as the soot graphitization. Most importantly, the concentration of carcinogenic high molar-weight polyaromatic hydrocarbons (PAHs) is reduced due to the pentanol presence in the jet fuel. Increasing pentanol reduces the genotoxic potential of soot considerably. Thus, optimization of the pentanol content in jet fuel could eliminate the genotoxicity of soot and bound PAHs from aircraft engines.

Since the implementation of the Clean Air Act in 2013, China's annual average of fine particulate matter (PM_2.5) has decreased by over 50%. However, haze episodes continue to affect the North China Plain (NCP) during winter. The formation of secondary organic aerosols (SOA) in light of these emission reductions remains poorly understood. In this study, we conducted a model-assisted analysis of field sampling data in Shijiazhuang, revealing that SOA has surpassed primary organic aerosol (POA) in prominence during the winter haze of 2024 compared to 2014.

Due to low regulatory requirements, VOC monitoring is only sparsely done in german and EU air quality monitoring networks. A laboratory intercomparison under different sample air humidities of four commercially available online-GC for VOC monitoring was done. Additionally, three of them were tested in a two-month winter field campaign and two of the instruments were deployed for 1 1/2 years in a field test. Due to significant maintenance efforts, caused by a variety of hardware and software issues, only 73-76% of data availability were achieved. Most data quality issues arose from significant peak shifts and thus peak misclassifications.

Many automatic monitors of airborne bioaerosols are based on machine learning algorithms for classification and allow real-time detection and quantification of allergenic pollen grains. These methods are still under rapid development and require regular evaluation. The objective of this study is to evaluate the performance of the SwisensPoleno Jupiter in Wrocław (Poland) for a two-year period. During this period, two classification models were used: one trained on Switzerland's pollen data and the other adapted to Polish data. Validation has been conducted using pollen concentration data obtained from manual measurements with a Hirst-type pollen trap.

Ambient monitoring of aerosols typically measures mass concentrations resulting in ultrafine particles (< 100 nm) being overlooked despite their potential for increased toxicity relative to larger particles. Here, we characterize a novel, mid-cost device for the ambient monitoring of ultrafine particle number concentration and mean diameter for both total and solid particle fractions. The device performed extremely well when tested with soot areosol with median diameters from 15 - 120 nm. At 200 nm and 10nm, particles were still measured reliably but with reduced counting efficiency. Good agreement was also seen for the particle size at all conditions tested.

The study compares the penetration efficiency of ultrafine particles in two aerosol spectrometers, Nanocol and SDI2001. Nanocol, designed for high flow rates, significantly outperforms SDI2001, achieving over 70% penetration efficiency for 5 nm particles compared to SDI2001’s 10%. This improvement is attributed to Nanocol’s refined inertial impaction stage, enhancing accuracy in ultrafine particle classification. The findings suggest the need to revise SDI2001 values for better ultrafine particle deposition assessments. Future work will focus on validating diffusion battery channels and refining theoretical models to improve characterization accuracy.

Cyclone efficiency data has traditionally been measured using an aerodynamic particle sizer (APS) (Maynard and Kenny, 1995), where aerosol size distribution measurements are taken upstream and downstream of the cyclone. However, “phantom” particle counts in the APS can result in measurement errors. Here the use of an aerodynamic aerosol classifier (AAC) and condensation particle counter (CPC) is explored for this application. The AAC classifies particles by their aerodynamic diameter and has the potential to make cyclone efficiency measurements with a broader range of aerosol sources, without measurement artifacts.

We study a passive-flow Universal Cloud and Aerosol Sounding System (UCASS) for measuring aerosol and droplet size distributions during balloon soundings. We introduce an improvement by implementing a thermal flow sensor (TFS) to continuously measure UCASS flow velocities. Our balloon sounding experiments show that significant non-zero angles of attack occur during ascent, emphasizing the need for independent measurements. In-flight comparisons reveal discrepancies between GPS/pressure-derived and TFS-based velocities, leading to potential misestimation of concentrations. We found that TFS velocities are reliable up to 7.5 km altitude in mid-latitude conditions, but may be biased at higher altitudes due to low air density.

The counting efficiency (CE) of condensation particle counters (CPCs) depends on factors such as working fluid (WF) properties and particle composition. This study evaluates alternative WFs to minimize material dependence while ensuring safety. Using simulations, experiments, and safety assessments, three WFs - n-decane, propylene-glycol, and HFE-7500 - were compared to n-butanol. Results indicate that n-decane exhibits the lowest material dependency, while propylene-glycol and HFE-7500 show varying influences. Findings suggest n-decane as a promising alternative. These insights contribute to optimizing CPC performance with reduced material influence, particularly at 10 nm and 23 nm cut points.

In this study, we present an online methodology to determine cluster structures in their native states. The collisional cross-sectional area, which is highly correlated with cluster structure, can be easily obtained via DMA-MS system and theoretical approach, both of which exhibit considerable consistency. The developed tool for deriving cluster structures is highly precise and sensitive to a single atom. The results demonstrate the ability of the plasma method to create alloy clusters of arbitrary atom combinations and the versatility of the developed tool to directly obtain cluster structures with single-atom precision.

The Airmodus PSM2.0 is an advanced Particle Size Magnifier designed to measure aerosols in the 1–12 nm range. This study enhances its time resolution, reducing scanning time from 2 minutes to 30 seconds to improve measurements in dynamic environments. By optimizing flow geometry and increasing data logging frequency, scanning limits and calibration needs were assessed. Findings enable faster, more accurate size distribution measurements, particularly in nucleation studies and engine exhaust analysis. The results refine ultrafine particle detection methods, supporting atmospheric research and air quality monitoring in real-world applications.

Among various techniques for measuring size and size distribution of nanoparticles, in the study, electrospray scanning mobility particle sizer (ES-SMPS) technique was used. I have focus on sample preparation to determine size and number concentration of nanoparticles.

This research enhances the Dimer Coagulation, Isolation, and Coalescence (DCIC) technique for measuring aerosol particle viscosity, a critical factor influencing climate, atmospheric composition, and human health. Due to the bipolar charging efficiency of particles dropping dramatically with size, having a high PNC at smaller sizes is very challenging. The enhanced technique achieves a higher number concentration of smaller particles, by charging large particles and then evaporating them to smaller sizes. Under heating conditions, a significant shift in particle size distribution was observed. This method enables precise DCIC merge mode measurement down to 30 nm using sucrose as a test case.

If a dilution system is installed upstream a particle counter or aerosol spectrometer, the dilution ratio contributes linearly to the measured number concentration. Therefore, the uncertainty of the dilution rate is required to quantify the measurement uncertainty of the aerosol concentration for example when measuring the penetration of filters.

The contribution discusses the applied method to quantify the uncertainty of the dilution rate and aims on developing a common method to evaluate the uncertainty of dilution systems to enable the comparison of results.

Exposure to airborne particles in indoor environments is a significant concern for human health, as the presence of indoor particle sources leads to considerably higher concentrations of particles. In recent years, interest in 3D printers has grown exponentially, especially with their increasing use in homes, rising concern among users regarding emissions from these devices.

In this work an experimental campaign was carried out to measure particle number concentrations and size distributions while the 3D printer was in operation using TPE and TPU filaments.

All the tests performed showed that printing TPE and TPU filaments emit sub-micron particles.

In this work, we present the Fluidizer as a dustiness method currently undergoing standardization at OECD, and its performance in testing several nanomaterials including different fibrous nanomaterials.

Dustiness of eleven nanomaterials, from which 5 were fibrous nanomaterials, were assessed in two laboratories.

The coefficient of variation per laboratory was generally <35%. CPC and electron microscopy analysis for fibrous materials were in agreement. These results show the robustness of the Fluidizer method and applicability for dustiness determination of nanomaterials with different morphologies.

We present the development and use of a particle-on-slide methodology for the generation of light-scattering data on aerosols. This method is validated using simple, well understood model aerosols, however its chief interest is in the study of dynamic systems where it is desirable to gather data on the same particle over a period of time. Where this model is appropriate, it is simpler and more accessible than existing particle levitation methods, and allows for light scattering and microscopy data to be gathered in tandem.

The study at AppalAIR focuses on a new ePTFE tube humidifier designed to improve aerosol humidification. This system addresses challenges from previous designs, like water droplet formation, by using a highly porous membrane to transfer water vapor into a dry sample stream. The humidifier features a water jacket, stainless steel connectors, and a solenoid pump for slow, continuous water transfer. A controlled external heater adjusts the water temperature to regulate relative humidity. Extensive testing showed successful humidification, with the system operating for over two months in the field, demonstrating the design’s effectiveness for aerosol sample humidification.

AeroSolfd, a HORIZON Europe project launched in 2022, aims to advance clean urban mobility by developing affordable and sustainable retrofit solutions. This three-year initiative addresses not only tailpipe emissions, but also brake and pollution in semi-closed environments.

VERT has developed and tested a TRL 8 GPF-retrofit system. Results demonstrate >99% filtration efficiency on standard and real-world driving cycles. Fifty gasoline vehicles (GDI and PFI) were retrofitted across Europe exhibiting no issues with filter regeneration, increased fuel consumption, or secondary emissions during 6-8 months of operation. Furthermore, a PN-PTI testing campaign of 1000 gasoline vehicle was conducted. Final results are presented.

To date, there are few online measurement methods to quantify sub-micron sea spray concentrations. Aerosol chemical speciation monitors (ACSM) are not ideal for sea salt aerosol measurements because the refractory NaCl cannot be fully evaporated. In this study, we show the potential for the ToF-ACSM equipped with a capture vaporizer for detecting and quantifying NaCl aerosol for the first time. Laboratory experiments and controlled chamber experiments showed the potential of the CV-ToF-ACSM to quantitavely measure NaCl. Application of the method to measurements at a coastal site highlighted the ptential of the CV-ToF-ACSM for real-time sea salt aerosol measurements.

Within the European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS), measurements of chemical composition and concentration levels of non-refractory submicron particulate matter (NR-PM₁) were performed for the first time at the CNR-IMAA Atmospheric Observatory (CIAO, Tito Scalo – Italy, Laurita et al., 2025) from May to October 2024 using a Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM). This instrument uses time-of-flight mass spectrometry to continuously analyze air samples, even over extended periods, enabling precise measurements of chemical compositions of NR-PM₁, including ammonium (NH₄⁺), nitrate (NO₃^-), sulfate (SO₄^2-), chloride (Cl⁻), and organics aerosol (OA).

Carbonaceous aerosols impact climate and health, comprising 20–50% of PM2.5 mass. Thermal-optical carbon analysis (TOCA) is an established technique for organic and elemental carbon analysis, but enables molecular analysis when coupled with photoionization mass spectrometry (PIMS). We demonstrate TOCA-PIMS for wood type identification in stove emissions, distinguishing birch, spruce, and beech via unique thermal decomposition markers, as well as rapid PAH proxy- analysis from the same filter sample analysis. Moreover, hyper-fast gas chromatography as add-on may resolves isomers. This method expands chemical analysis capabilities, aiding atmospheric chemistry research and integration into routine air quality monitoring.

The subject of collecting and analyzing (physically and biologically) respiratory droplets became important since the last COVID-19 outbreak. Indeed, being able to physically characterize droplets (size distribution, emission rates and state) emitted by living beings will help advance our understanding of the transmission of airborne diseases in indoor environments. The main objective of this work is to propose a new experimental bench that allows to isolate and collect respiratory droplets in a controlled hygrothermal environment.

Bioaerosols such as pollen and fungal spores are ubiquitous in the atmosphere. Recent advancements in monitoring airborne biological particles using automatic bioaerosol monitors are based on image analysis, fluorescence, and machine learning. These systems provide real-time information on particle number concentration and classification at the taxonomic or species level. However, most studies have only focused on fresh bioaerosols for setting up datasets for machine learning. In ambient air, bioaerosols may change shape and property during aging and transportation, representing a key research gap. For this, we developed a new coupled experimental setup for the continuous generation of aged bioaerosols.

The SwisensPoleno Jupiter bioaerosol monitor automates pollen monitoring in Switzerland using holographic images and UV laser-induced fluorescence (UV-LIF) spectra, fed to a deep learning classification neural network. This study tested the robustness of the retrained model from Sauvageat et al. (2020) by sampling various pollen taxa and eliminating data leakages, which occur when training and testing datasets per taxon come from the same experiment. The model performed well for Pinus sylvestris (93% accuracy) but poorly for Betula pendula and Betula utilis (3% to 6%). Ongoing tests and conditioning of pollen grains aim to investigate parameters affecting the model's classification accuracy.

Bioaerosols are airborne particles with biological origin. At the ASC-ChAMBRe, bioaerosol research focuses on the interaction between bacteria and air pollutants. We used different methods for ASC experiments, including monitoring bacteria total concentration with WIBS-NEO and investigating culturable/viable bacteria concentration through different approaches. These include a multi-step protocol using an Andersen impactor, an automatic custom-made tray for collecting bacteria by gravitation on petri dishes and a liquid impinger for bacterial collection on various media depending on the analytical methodology chosen for the subsequent characterization. Here we’ll present the experimental protocols, their characterization and further results.

This study compares the performance of two bioaerosol generators: the Sparging Liquid Aerosol Generator (SLAG) by CH Technologies (SLAG CH Tech.) and the 1520 Flow Focusing Monodisperse Aerosol Generator (FMAG) by TSI (1520 FMAG TSI) , focusing on the viability, culturability, and cells fragmentation of E. coli.

This paper presents a new surface-sensitive measurement method for the characterization of aerosol aggregates based on the combination of aerosol photoemission and aerosol UV-vis-extinction. The adsorption of water vapor on TiO2 nanoparticles is considered as a test case.

The first method for selective detection of respiratory droplets is based on measurement of time-dependent capacitance . When droplets enter the electric field of the sensor, the capacitance is changed due to replacement of air as a part of dielectric field with water. This change is then converted into an electrical signal. The selectivity is explained by much higher dielectric constant of water compared to air, which is not the case for carbon-based particles. The device can detect individual respiratory droplets larger than 100 nm. Measurement of respiratory droplets in lecture hall and in kindergarten will be presented.

The ROS-Online device, developed at the IGE laboratory in Grenoble, enables real-time, continuous measurement of the oxidative potential (OP) of atmospheric particulate matter (PM). It uses two complementary assays, OP Ascorbic Acid (OPAA) and OP Dithiothreitol (OPDTT), to assess PM's ability to induce oxidative stress in the lung environment, a key factor in cardiovascular and pulmonary diseases. The device offers higher sensitivity and particle collection efficiency than offline methods, providing reliable data across varying pollution levels. ROS-Online’s performance correlates well with traditional offline methods, demonstrating its potential as an effective tool for air quality monitoring and research.

The present study aimed at developing an RH-based correction for a PM_2.5 low-cost sensor network by using a novel method called "the dual-sensor approach". Two identical sensor boxes with the Plantower PMS7003 were placed before and after the heated inlet. The setup was collocated with the regulatory-grade instrument for one week. The PM_2.5 concentration obtained by the sensor with the heater reduced the overestimation of the PM_2.5 concentration from 63% to 15%. However, the correction factor varied throughout measurement, meaning that the composition of the PM_2.5 changes depending on the wind direction, varying the hygroscopicity of the particles.

PTB uses calibrated instrumentation for aerosol elemental analysis and contributed to many aerosol metrology projects: EMPIR AEROMET initiated multiple measurement campaigns and developed reference methods and calibration procedures, the follow-up project AEROMET II focused on traceable measurements and characterisation of aerosols by means of portable instruments, and the current MI-TRAP project aims to establish a network of monitoring stations addressing discrepancies between transport emission standards and ambient air quality limit values. Examples of PM characterization using reference-free quantification of the mass of the deposited material will be given, summarizing methodological findings paving the way to round robin and related activities.

WALL-E is a newly designed Wall-Free Particle Evaporator enabling real-time aerosol analysis with minimal wall interactions and fragmentation. Integrating a thermal desorber, cooling unit, and CIMS, it optimizes fluid dynamics to reduce thermal decomposition, improving quantification of semi-volatile and low-volatility species. Controlled experiments with authentic standards and oxidized VOCs demonstrate its performance. WALL-E provides high-resolution molecular insights into aerosol composition and volatility, making it a valuable tool for studying atmospheric processes, emissions, and environmental health impacts in both laboratory and ambient environments.

Accurately measuring the microphysical properties of clouds and aerosols remains a major challenge due to their complexity and variability. The newly developed Ground-Based Fog and Aerosol Spectrometer (GFAS) advances these measurements by combining forward and backscattered polarized light detection. In addition to measuring particle size (0.4–40 µm EOD), the GFAS provides information on backscattering intensity and polarization changes, helping to distinguish liquid droplets from solid particles such as ice crystals and dust while reducing sizing biases. Its automated wind-alignment minimizes sampling losses. We present first results from laboratory experiments and field deployments, demonstrating the instrument’s capabilities.

This study explores the use of Platanus × acerifolia (plane trees) as passive biomonitors for urban air pollution in Paris. Tree bark samples, collected since 2016 through the Ecorc’Air project, provide insights into fine particulate matter (PM) accumulation. Magnetic susceptibility measurements quantify iron-rich particles, while SEM imaging confirms PM trapping. Statistical analysis identifies key urban pollution hotspots. XRF and ICP-MS determine metal compositions linked to vehicular emissions. Ongoing research evaluates potential health risks using oxidative potential and cytotoxicity assays. Funded by CARINGS, the project involves Mines Paris-PSL, IMT Nord Europe, and Mines Saint-Étienne.

Air quality is a major health concern in Europe, with particulate matter (PM) being one of the main pollutants. The recent EU Directive 2881/2024 imposes stricter limits on PM10 and PM2.5 and highlights the need for supersites to enhance monitoring.
In response, the Le Grazie supersite in Terni, one of central Italy’s most polluted cities, was established to characterize PM chemistry using instrumentation for online measurements. The high temporal resolution data provided by this instrumentation enables source apportionment analysis. The presentation will outline the instrumentation, its strengths and weaknesses, and initial findings on pollution sources.

This study investigates the use of a Dimethyl Sulfoxide (DMSO)-water mixtures as a working fluid in Condensation Particle Counters (CPC), as it offers several advantages for CPCs operated in sensitive working environments. It has been shown that the D50-cutoff diameter is dependent on the temperature difference within the CPC operated with pure DMSO, where greater temperature differences result in smaller cutoff-diameters.

We will present the behaviour of a CPC operated with mixtures of DMSO and water including a detailed report on the counting efficiency, during various measuring conditions, focusing on the temperature difference between the condenser and the saturator.

This study presents an optimized methodology using Unmanned Aerial Vehicles (UAVs) equipped with an integrated system of low-cost sensors (LCSs) to obtain real-time vertical and horizontal pollutant dispersion profiles in three different environmental settings: urban, rural, and industrial. This approach aims to overcome the limitations of traditional methods by enabling high-resolution, near-surface vertical profiling of air pollutants.

The methodology involves adapting a monitoring unit, incorporating AQ LCSs previously validated by the authors, to a customized commercial UAV platform (DJI Matrice 210). The UAV is equipped with GPS, a black carbon (BC) instrument (MicroAeth® AE51), and a multi-pollutant monitoring unit (MU).

Polarized side-scattering measurements enhance aerosol characterization in the SwisensPoleno Jupiter. The system records p- and s-polarized light intensities from particles illuminated by a 405 nm laser. The polarization ratio (PR) is determined by integrating mid-section scattering signals, effectively distinguishing biological particles (e.g., pollen) from water droplets. PR values are consistent across multiple instruments. This method complements holography and fluorescence spectroscopy, improving real-time aerosol identification and atmospheric monitoring accuracy.

The aim of the exposomic is to understand how exposures from environment, diet and lifestyle interact with our genetic background.The MAMELI Project aims to investigate a wide range of environmental factors in an urban population. A network of 16 low-cost real-time air quality monitors was located in the city hosting the living lab (Legnano, Italy). Moreover, three reference grade instruments for the target pollutants have been installed and co-located. The data collected by this network opens several research opportunities in the exposure sciences field because of their high level of detail on the spatial and temporal variability.

Carbonaceous aerosols (CA) are usually the most significant contributor to fine particulate matter (PM2.5). They are frequently separated into Organic Carbon (OC) and Elemental Carbon (EC) based on their volatility using thermal-optical methods.

The Aerosol Magee Scientific Total Carbon Analyzer TCA08 is a scientific instrument that measures the Total Carbon ("TC") of suspended aerosol particles in near real-time using a simplified thermal method (Rigler et al., 2020). Combining Total Carbon Analyzer TCA08 and Aerosol Magee Scientific Aethalometer® provides a novel approach for measuring TC, eBC, OC, and EC content of suspended aerosol particles in near-real-time with high-time resolution.

The Future Homes Standard, set for 2025 in the UK, outlines guidelines for "zero-carbon ready" homes by improving energy efficiency, low-carbon heating, and fabric performance. However, these improvements may impact indoor air quality. Ventilation strategies like MVHR and DMEV help mitigate this while maintaining efficiency.

To assess their effectiveness, low-cost sensors from Quant AQ and AirGradient were strategically deployed across Bellway’s Future Home at the University of Salford’s Energy House 2.0 and Controlled experiments were performed. PM₁ concentrations were measured using these sensors, indicating that DMEV and MVHR reduce aerosol concentrations by up to 99% in future home's various locations.

Residential solid fuel burning is Ireland’s main winter air pollution source. The TownAir project assesses the impact of 2022 solid fuel regulations by identifying PM₂.₅ sources. A field campaign in Enniscorthy (Winter 2024/2025) used regulatory EPA monitors, a low-cost sensor (LCS) network, and advanced instruments. A concentration similarity index (CSI) compared PM₂.₅ across the LCS network, with preliminary results showing higher levels in older residential areas. Source apportionment via PMF will be conducted using a low-cost sensor and will complement chemical characterization. A future campaign in Letterkenny (Winter 2025/2026) will offer comparative insights into regional pollution trends.

Urban areas are particularly vulnerable to elevated pollution levels. To measure concentrations of pollutants, the spatial and temporal resolution of the measurement are a key factor. Low-cost sensors can be an effective tool in the assessment of exposure to air pollutants. Following a year of experimentation using two LCS stations, a calibration methodology was developed.Ten low-cost micro-sensor stations called MoNiCa were fixed to monitor PM and NO₂ in Turin. Throughout the campaign, trends in the concentrations of the pollutants were consistent with the meteo-climatic, traffic and positioning characteristics. Based on this research, LCS proved to be complementary to canonical instrumentation.

This study develops a machine learning calibration model for a network of low-cost air quality sensors using emission inventory data for source specific corrections. The approach leverages cross-validation among nearby and co-located sensors, enhancing model robustness. A Data Reliability Indicator assesses performance across income group countries, improving reliability and spatial transferability compared to conventional approaches, which lack fine-scale and source specific insights.

Filter-based absorption photometers, particularly aethalometers, are used to measure equivalent black carbon (eBC) concentrations. Portable models like the microAeth® AE51 and MA200 enable high-resolution monitoring for personal exposure and BC mapping. As part of the RI-URBANS project, 13 devices were mounted on courier bicycles in Milan to assess BC spatial variability. The AE51 proved more robust than the MA200, which experienced software crashes due to vibrations. Both devices correlated well with the reference AE33, though MA200 required longer stabilization periods. Noise issues at 1-second resolution required post-processing. Findings help refine mobile BC monitoring methods and assess urban pollution mapping.

Black carbon (BC) is emitted in the atmosphere by incomplete combustion processes and impacts both human health and climate. Traditional BC monitoring methods are expensive, limiting spatial and temporal coverage. The bcMeter is a recently developed low-cost (<300€) BC monitoring device that can facilitate the spatial coverage of BC measurements.The performance of two bcMeter was evaluated at an urban background site in Mülheim-Styrum (Germany) against reference data from an AE33 aethalometer. The bcMeter provided results comparable with a reference aethalometer in daily averages, proving a promising option for future application in monitoring networks, where daily data resolution is sufficient.

This study develops a novel hybrid approach integrating satellite data and a large-scale low-cost sensor network using machine learning to generate high-resolution PM2.5 maps at a 200m scale over Bihar, India. A dataset from 511 sensors (May 2023–April 2024) was preprocessed, calibrated, and supplemented with ERA5 data. A GNN-based model outperformed previous models, achieving RMSE of 12.35 μg/m³ and Pearson’s r of 0.9. The analysis identified northern Bihar as more polluted due to population clusters and land use. Findings highlight intra-state pollution sources and seasonal variations, aiding policymakers in developing targeted air quality management strategies.

This study presents an approach towards the development of customized electrochemical sensors using conductive PLA composite via fused filament fabrication (FFF) for electrochemical application. A PLA-based composite reinforced with graphene nanoplatelets (GNP), multi-walled carbon nanotubes (MWCNT), and lithium titanate oxide (LTO) was fabricated and characterized. Electrical conductivity increased by 12,065%, tensile strength by 64.3%, and compressive strength by 103.7% compared to pure PLA. Thermogravimetric analysis showed improved thermal stability (361.54°C). These findings validate the potential of 3D-printed electrochemical sensors as a low-cost, efficient, and scalable alternative for detecting heavy metals and air pollutants in environmental applications.

The TRAMONE (Trajectory-based Monitoring Network) research project is being presented. Its aim is to develop a low-cost, intelligent, autonomous system for atmospheric aerosol sampling on filters, utilizing mobile data network control. The system enables sample collection based on near-real-time air mass trajectory calculations. The software controls the samplers based on whether the trajectory corresponds to a predefined path, serving as an alternative to expensive continuous sampling and subsequent filter analysis. The hardware and software will be freely available for public use.

In the framework of the DivAirCity Project, aimed at improving Air Quality in Cities through Social Inclusion and Nature Based Solutions, an integrated approach to monitoring, in which conventional instruments and both home-built and commercially available sensors, was undertaken.Both Airly sensors and PM conventional measurements by gravimetry were employed. The optical sensors measure PM by light scattering, and physical properties of the particles, which vary with location and season, may influence the accuracy of the results. Anyway the agreement between data obtained by gravimetry and sensor values was quite good (R²=0.89), and the trends recorded are in general comparable.

Real-time and in situ monitoring of bioaerosols using laser-induced fluorescence is promising, but the specialised instruments designed for this purpose are often large, heavy (typically 20–40 kg), and costly. We introduce a newly designed, low-cost miniaturized Bio-OPC and evaluate its feasibility for detecting various bio-fluorophores in the laboratory. We demonstrate its ability to detect bacteria and pollen in different environments. Compounds such as β-NADH (Nicotinamide adenine dinucleotide) at varying concentrations were used as fluorescent materials, and monodispersed aerosols were generated in the lab to test the sensitivity of the instrument.

Occupational diesel exhaust exposure levels are not well quantified in many working sectors and new information is also needed on the use of new miniaturized measurement instruments such as micro-aethalometers and ultrafine particle counters for the assessment of occupational exposure. In this study, occupational exposure of bus drivers, mechanics, construction workers and inspection station workers were measured with these instruments. High momentary diesel exhaust concentrations were detected. The correlation between lung deposited surface area and equivalent black carbon indicates that black carbon plays an important role in exposure to fine particles in the studied workplaces.

Air quality deterioration is a growing concern due to urbanization, industrial emissions, and transportation. NO2, a harmful pollutant, poses health risks, prompting strict exposure limits. Effective NO2 sensors must be highly sensitive, selective to confounders analytes, and energy-efficient. While chemoresistive metal oxides offer sensitivity and fast response, they lack selectivity and require high temperatures. Metal nitrides, like Cu₃N, show promise due to excellent catalytic properties. A novel method using aerosol deposition and dry nitridation yields highly porous Cu₃N sensors, achieving excellent NO2 detection at low temperatures (few ppb) enabling cost-effective, miniaturized air quality monitoring networks.

The current study investigates the applicability of low-cost PM sensors for their future use as a reliable instrument for outdoor particulate matter (PM_2.5, PM₁₀) measurements. The evaluation of the accuracy and reliability of the sensors was carried out through linear regressions applied between the particulate matter concentrations (PM₁₀, PM_2.5) measured by a reference instrument and the concentrations measured by the low-cost sensors. Subsequently, the deposited dose was estimated for each region of the human respiratory tract (HRT) using the corrected PM_x concentrations (sensors)_.

Trace elements in particulate matter (PM) are crucial for source apportionment due to their health impacts. Their measurement can be done using online (e.g., Xact 625i XRF) or offline (ICP-MS, ICP-OES, XRD) methods. This study compares online XRF and offline ICP-MS/ICP-OES data from four European sites: Deskle (SLO), Sarajevo (BiH), Barcelona (ES), and Nova Gorica (SLO), with differing PM sizes, digestion methods, and sampling periods. Results show strong correlations for S (r² > 0.90) and Cu (r² > 0.80). Correlations for Pb, Zn, and K vary by site and season, influenced by sources, matrix effects, and special events.

This study explores the effectiveness of various measurement platforms—bicycles, trams, tethered balloons, drones, and low-cost sensors—in monitoring aerosol concentrations and meteorological parameters. Mobile platforms, such as bicycles and trams, collect high-resolution data along urban transit routes, identifying pollution hotspots. Aerial platforms, including tethered balloons and drones, extend monitoring to vertical profiles, assessing pollutant dispersion. The use of low-cost, real-time sensors has further enhanced air quality studies by enabling widespread and continuous data collection. The talk will compare these platforms, discussing their advantages, limitations, and contributions to air quality investigations.

In this work we present results from a laboratory characterization exercise of three PAS instruments and an aethalometer, for the measurement on black carbon and brown carbon with known EC/OC content. We evaluated the time response and the linearity for different particle size distributions and mass concentrations.

In the first step of an integrated study of aerosol liquid water content and cloud condensation nuclei spectra, a field campaign collected size distributions and hemispheric backscattering fraction data, among others. This presented us with the unique oppertunity to see how well correlated particle size is to light scattering with practical data instead of simulated. We found these values to be correlated at all 3 wavelengths studied.

Saharan dust storms can travel thousands of kilometers, impacting air quality, human health, and economies. The CIAO observatory in Potenza, Italy, frequently experiences these intrusions, especially in spring and summer. Between 30 March and 1 April 2024, an extreme Saharan dust event affected the Mediterranean and Europe. At the conference, we will present lidar and in-situ aerosol observations from this episode, highlighting their complementarity. Lidar data reveal dust layer dynamics, while particle size distribution measurements confirm increased fine and coarse particle concentrations, peaking on 31 March when dust was confined to lower altitudes.

Organosulfates (OSs) are important compounds in atmospheric aerosols, but their formation and impact on climate and air pollution remain uncertain. This study analyzes offline particle samples from the CLOUD chamber, comparing results with semi-online particle analysis to improve understanding of OS formation pathways and properties.Using high-resolution mass spectrometry, compounds could be accurately assigned. By comparing different methods and chemical compositions, the study aims to enhance the identification of OSs and understand discrepancies caused by factors like aging and sample handling, offering insights into the formation and distribution of OSs in atmospheric aerosols.

Peroxides play a crucial role in atmospheric chemistry contributing to the mass of secondary organic aerosols (SOA), with important health implications. The fluorescent DCF-HRP method, while useful, lacks selectivity for H₂O₂.

This study presents a selective electrochemical sensor for determining H₂O₂ in atmospheric samples. Screen-printed carbon electrodes were modified with an conducting polymer and platinum nanoparticles, enabling direct H₂O₂ measurement via flow injection analysis with chronoamperometric detection. After optimizing instrumental and chemical parameters, the sensor demonstrated selectivity for H₂O₂ over other commercial peroxides. Finally, it was successfully applied to the analysis of laboratory-generated SOA, comparing favorably with the DCF-HRP method.

Fine particulate matter (PM2.5) and carbonaceous aerosols significantly affect atmospheric radiative balance and air quality due to their optical characteristics. In this study, we present a detailed look at how aerosols affect light and how they absorb light across different regions. Our research specifically investigates combustion aerosols from various urban and industrial sources, studying their absorption characteristics and impact by both in-situ and filter-based measurement methods. Such efforts allow us to study the impact of geographic and climatic factors on aerosol absorption and scattering characteristics, improving climate models and air quality assessment.

The bacterial and fungal aerosols were sampled at workplace in poultry house using six bioaerosol instruments: six-stage Andersen and single-stage MAS impactors, Coriolis µ and BioSampler impingers, open-face filter cassette, and COUNTERFOG^® BIAFTS sampler. The collected microbiota were quantitatively and qualitatively assessed using NGS. Alpha diversity metrics revealed that the highest richness and evenness of bacterial biota was observed in samples collected with Coriolis µ impinger, whereas fungal biota in samples collected with both MAS impactor and Coriolis µ impinger. Beta diversity showed that bioaerosol samples from Coriolis µ impinger were significantly different from those isolated with other tested samplers.

A crucial activity to support the Mutual Recognition Arrangement of the International Committee for Weights and Measures is the delivery of formal comparison exercises between National Metrology Institutes and, where appropriate, Designated Institutes and other reference laboratories.

Ten laboratories have participated in an experimental campaign for the CCQM-K185/P237 comparison, which measures the particle number and charge concentration of 30 nm and 50 nm monodisperse soot, and 80 nm and polydisperse soot nanoparticles.

We present the results from earlier aerosol metrology comparisons, set out the scope and experimental campaign for the CCQM-K185/P237 comparison and highlight some provisional findings from this exercise.

Cities are major CO₂ and particulate sources. The eddy covariance (EC) method, which relies on tower-based measurements, quantifies emissions on a larger scale but misses fine-scale processes like identifying single emission hotspots. To address this, EC is combined with mobile measurements using the aerodynamical resistance approach to calculate high-resolution fluxes. This approach, applied to CO₂ fluxes, is being expanded to study local particle fluxes in Berlin. Long-term EC measurements and mobile campaigns, using bicycles and cars, identified emission hotspots. These measurements show strong correlations between emissions, traffic, and turbulence, providing valuable data for dispersion models, though methodological deviations are expected.