This study targets to determine the oxidative potential (OP) of fine aerosols in an urban-industrial area near Lisbon and to identify the pollution sources with impact on the OP levels. For this purpose, thirty samples were selected from a set of 128 samples collected over one year, based on the highest load for each source, previously assessed by PMF source apportionment. Sig­nificant correlations between OP^DTT_V values and the mass contributions of the different sources to PM_2.5, were found for the sources vehicle exhaust, fuel-oil combustion and industry, which were found to explain 82% of the OP^DTT_V variability by MLR analysis.

This study examines persistent organic pollutants (POPs), including PAHs, OPEs, and PBDEs, in southern Taiwan during the northeast monsoon (Feb–Mar 2024). Urban sites had higher pollutant levels due to industrial and traffic emissions, with Xiaogang showing the highest BaPeq levels. OPEs (4.57±2.81 ng/m³) exceeded PBDEs by two orders of magnitude, highlighting a shift toward phosphorus-based flame retardants. PAHs were dominated by low-molecular-weight compounds, mainly naphthalene. Correlations suggest combustion as the primary source in rural areas. Seasonal fluctuations were driven by local emissions rather than long-range transport, emphasizing the need for targeted air quality management strategies.

In this study, we have designed and constructed a multifunctional bipolar electrospray aerosol generation platform, through which we systematically investigated both the charge distribution of resultant particles and the factors influencing the particle coalescence. A preliminary demonstration of the total charge measurements of sucrose particles generated by the developed bipolar ES platform as a function of feeding flow rate is presented in the article.

To print nanostructures over a large area remains a challenge, because the resolution and scalability often conflict to each other. Here we programmed a pulsed electric field for printing periodic nanostructures over an entire wafer. These nanostructures are bridge-like in geometry, connecting two isolated pads. As such, they act as the interconnects. The minimum wire-thickness was experimentally realized to 17 nm while maintaining the multimaterial ability to print the next-generation metals. The extensively large area exceeds the previous work by 4 orders of magnitudes. Their conductivities are also measured and predicted, comparable to those using film-technologies.

Wildfires significantly impact air quality and climate, with increasing frequency and intensity expected in the coming years. Currently, wildfire-related emissions contribute 7–10% of near-surface PM2.5 in French background regions during summertime. This study investigates biomass burning (BB) aerosols at the ATOLL, northern France, site using in-situ and remote sensing techniques. The INTERPLAY method, previously applied to winter heating emissions, is adapted to assess BrC aging from wildfires. Case studies from 2017, 2019, and 2022 highlight transboundary transport. Findings enhance source attribution methods and improve BrC quantification, informing air quality assessments and climate models through integrated ground-based and satellite observations.

Transport emissions contribute to airborne particulate matter (PM) and impact health through primary and secondary aerosol (SecA) formation. The PAREMPI project assesses the toxicological effects of emissions using an air-liquid interface (ALI) in-vitro model. In the Light-Duty (LD) campaign, five vehicles were tested under real driving emissions (RDE) conditions at +23°C and -9°C. Toxicity assessments revealed higher cytotoxicity (V1, V3, V4), oxidative stress (V3, V5, V4), and DNA damage (V3, V4, V6), with cold-start conditions upregulating antiviral defense genes. These findings highlight the need for emission regulations reflecting real-world toxicity risks.

Aircraft particle emissions at the engine exit are largely composed of Ultra Fine Particles (UFPs, D <100 nm) which can cause adverse health effects. In November 2022, we deployed a state-of-the-art set of gas- and aerosol-phase instrumentation 1 km near Zürich airport to characterize aircraft UFPs. Measurements showed that airport activities bring high UFPs number concentrations to the site with a small mean diameter (around 17.5 nm), that can significantly grow by condensation/coagulation. An increase of the UFPs concentration with lubrication oil markers signal has been found, highlighting that their online detection can predict high UFPs concentrations from the airport.

Here, soot is produced by enclosed spray combustion of jet fuel blending with pentanol. The concentration, morphology and chemical composition of the generated soot are characterized using real-time and time-integrated sampling instrumentation. Most importantly, increasing the pentanol content in the jet fuel decreases the genotoxic potential of soot and carcinogenic polyaromatic hydrocarbons (PAHs) up to 87 % and the surface area of the deposited soot, an important metric that determines its cytoxocity, by 36 %. Thus, optimization of the pentanol content in jet fuel could eliminate the public health impact of soot and PAH emissions from aircraft engines.

Aerosol absorption and scattering coefficients were measured continuously in Milan for 1-year. Scattering data are the first ones obtained in Milan (Italy) and are still scarce in urban environments. From the Absorption and Scattering Angstrom Exponents provided information on the fossil fuel vs. wood burning presence as well as on particle-size dependence, respectively. An optical source apportionment was performed through the revised MWAA Model combined with the Aethalometer Model. In addition, absorption and scattering measurements were combined to retrieve aerosol typing (e.g. Saharan dust, local soil dust resuspension, wood burning, fossil fuel emissions).

The abstract reports experimental measurements of atrmospheric heating rate induced by light absorbing aerosol. These measurements were collected in the Po Valley at a urban (Milano) and rural site (Schivenoglia) during 2023. Measurements were collected at 1 min time resulution in any sky condition. Source and species apportionment of light absorbing aerosol allowed to determine the contribution of fossil fuel, biomass burning, black carbon and brown carbon on the heating rate. Moreover, brown carbon was apportioned between primary and secondary origin highlighting the climatic effect of both contribution in the atmosphere.

This study uses BLAnCA, an innovative, high-resolution laboratory instrument, to measure spectral absorption across the UV-NIR range of mineral dust samples from several arid areas around the world. The measurements reveal distinct optical properties tied to mineral composition.

This study was conducted at three distinct locations in Spain, representing different atmospheric environments: an urban site in Barcelona (77 m a.s.l.), a regional background site in Montseny (720 m a.s.l.), and a continental site in Montsec (1600 m a.s.l.). The primary objective of this research is to characterize the absorption properties and heating rates of black carbon (BC) and mineral dust (MD), with respect to their size distribution.

This study presents a novel approach using bipolar electrospray for synthesizing TiO₂/Ag heteroaggregates, ensuring stable and efficient nanostructure formation. The method leverages electrohydrodynamic atomization to generate charged droplets, allowing precise control over particle formation. A detailed investigation into process stability includes current-voltage (I/V) analyses, optimizing parameters such as voltage, flow rate, and solution properties. Additionally, an advanced microscopy system is introduced to capture high-resolution images of droplet interactions, providing insights into coagulation mechanisms. This research highlights the potential of bipolar electrospray and advanced imaging for optimizing nanomaterial synthesis, particularly for photocatalytic applications.

The fragmentation of liquid jets by a gas stream plays a critical role in advanced materials production due to its high efficiency. Pneumatic techniques, such as Flow Blurring (FB), promote droplet formation by inducing microscale mixing. This approach has been successfully adapted for viscous liquids, enabling the generation of droplets, micro- and nanoparticles, and fibrous materials. Recent advancements combine FB atomization with electric charging, facilitating the synthesis of polymer fibers embedded with nanomaterials like carbon nanotubes and graphene oxide. Current research efforts focus on developing an FB device with integrated high-voltage electrodes to enhance atomization efficiency and optimize material collection.

We introduce a model of the field emission of small ions from a cloud of evaporating electrospray nanodroplets of a salty solution.

Effective inhalation therapy requires precise aerosol size and distribution for targeted lung delivery. Electrospray (EHDA) generates uniform micro- and nanodroplets, improving drug delivery. Gilbert b.v. is developing an EHDA-based inhaler for complex lung conditions. This study investigates droplet neutralization and electrospray control in a soft mist inhaler using a multi-nozzle system and corona discharge. A stable cone-jet region was mapped, and optimal neutralization voltage was identified for ethanol-based solutions. Future research will focus on spray stability with reduced ethanol content and its impact on droplet size and drug delivery efficiency.

Urban road dust may contain potentially hazardous pollutants which may cause adverse health effects. Road dust samples were collected on construction sites and analysed to determine specific tracers and potential health-related effects. Pseudowollastonite was successfully identified as a unique tracer for construction and demolition works. Significant concentrations of toxic heavy metals were found in the fine fraction of construction-related road dust, which implied enhanced health risks. The primary cytotoxicity assays showed a definite concentration-dependent decrease in metabolic activity and loss of viability, as well as increased intracellular ROS levels and decreased mitochondrial activity compared to the control.

We have equipped welders with 2 Partector 2 Pro, one inside the PAPR mask, and one in the breathing zone outside the mask. The protection of the PAPR mask was 124 while welding but due to non-welding tasks with the mask off, the total protection factor over a full work day was much lower, only around a protective factor of two.

This shows the importance of wearing the PAPR mask during the full work day.

Rising global metal demand increases worker exposure to toxic airborne metal aerosols in mining and processing. Traditional monitoring lacks real-time tracking and elemental analysis. In September 2024, we assessed copper mining stages using advanced instruments, including the XACT 625i XRF analyzer, optical particle counters, and impactors. Personal exposure measurements combined with near real-time and time-integrated sampling to assess inhalable and respirable dust fractions. Findings revealed significant variations in PM10 metal concentrations. Positive Matrix Factorization will help identify aerosol sources. Insights will guide targeted health interventions and regulatory compliance, improving workplace air quality and advancing real-time exposure assessment methods.

Occupational exposure as firefighter has been classified as carcinogenic to humans. Fires in buildings release large amounts of air pollutants to nearby areas, with unknown health impacts. Fire smoke consists of a range of toxic compounds in the particle and gas-phase including Polycyclic aromatic hydrocarbons (PAH).

The study involves a unique combination of upscaled room size compartment fires in eight different environments, aerosol characterisation using a mobile lab and extensive toxicological studies of PM emissions. The results show how aerosol emissions and toxicity depend on burning conditions and different fire scenarios.

The ARTofMELT expedition (May–June 2023) aboard the research icebreaker Oden offered a unique opportunity to investigate Arctic aerosol properties during the spring-to-summer transition. Using a combination of Nano-IR, Total Carbon, and HR-ToF-AMS analyses, we characterized accumulation- and Aitken-mode particles, examining variability in their loading and composition, as well as their mixing state and microphysical properties. These findings will help improve our understanding of aerosol-cloud interactions in a poorly observed region during this critical seasonal transition, shedding light on processes involved in the onset of sea-ice melt.

The Arctic oceans are a quantitatively important reservoir for biological ice nucleating particles (bioINPs). These are emitted to the atmosphere through sea spray, and are linked to Arctic cloud formation. Due to accelerated sea ice melt, sea ice microorganisms are progresively discharged into the surface waters, potentially contributing to marine bioINPs. We used field experiments and laboratory simulations to investigate bioINPs in fast and pack ice, looked into physical and microbial factors driving bioINP concentrations, as well as emissions of bioINPs from melted sea ice. Our results will be essential for constraining future climate change predicions for the Arctic region.

Arctic aerosols were collected during the ARTofMELT expedition and during two ground-based field campaigns in Disko Bay (West Greenland) and Young Sound (East Greenland), followed by analysis using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-MS). Aerosol samples from ARTofMELT showed the presence of compounds derived from oceanic fatty acids and monoterpenes, among others. Primary marine aerosols influence the composition at Young Sound. Aerosol samples from Disko Bay show a correlation between monoterpene-derived oxidation products indicating long-range transport from marine or terrestrial monoterpene sources. A comparison between the field measurements will provide a large-scale analysis of the Arctic environment.

Low-level mixed-phase clouds in the Arctic strongly influence the surface energy balance, but their representation in models remains poorly constrained due to large uncertainties on aerosol-cloud interaction processes. Combining detailed in situ aerosol and cloud measurements, collected from a tethered-balloon system in the central Arctic in June 2023, with modeling approaches, this case study quantifies the contribution of entrained free tropospheric aerosols to the cloud’s number of droplets and radiative properties. These findings highlight the need for more systematic vertical aerosol-cloud profiling to improve our knowledge of free tropospheric aerosol characteristics and their influence on clouds’ radiative properties.

This study investigates the role of highly oxygenated organic molecules (HOMs) in new particle formation (NPF) within the context of both biogenic and anthropogenic volatile organic compounds (VOCs). Using the CERN CLOUD chamber, we explore the chemical and physical processes that drive gas-to-particle processes under varying atmospheric conditions. The chamber experiments involve the introduction of α-pinene, isoprene, and trimethylbenzene to simulate biogenic and anthropogenic emissions. Real-time monitoring with mass spectrometers and particle analyzers allows for tracking the transition from gas to particle phase, shedding light on how human emissions impact NPF and contribute to atmospheric aerosol formation and climate change.

NPF is often suppressed in polluted cities due to high CS, yet it occurs in Delhi. We analyzed a year of size distribution and PM₂.₅ composition data to investigate influencing factors. While some studies suggest particle composition affects CS via hygroscopicity, our findings indicate it was not a key factor. Instead, RH variations influenced ALWC, which played a crucial role in promoting or inhibiting NPF. This underscores the variability in polluted environments, where meteorological conditions, especially RH, significantly impact NPF occurrence.

The study investigates New Particle Formation (NPF) in Milan, a polluted city in the Po Valley, Italy, over one year (2023 – 2024) by analyzing particle number size distributions. The results reveal a clear seasonal cycle, with winter showing higher concentrations of larger particles due to higher atmospheric stability and heating emissions, while summer exhibits stronger NPF, favored by increased mixing. The analysis shows that strong ventilation, low pollution and low airmass residence time in the Po Valley and exposure to anthropogenic sources promote NPF. These findings enhance our understanding of urban air quality and enable comparisons with other cities.

Identifying the specific causes of NPF in urban areas remains challenging.

In this study, we employ artificial intelligence approaches to predict the formation rate (J) and examine the role of highly oxygenated organic molecules (HOMs) in NPF events.

The models were trained on data collected in August 2022 in two nearby sites in Leipzig, Germany: an urban background and a roadside. The data comprised meteorological variables, NOx, BC, and CIMS (with PMF of HOMs).

Our models accurately predicted the J at the background site. Additional analysis identifies sulfuric acid, amines and various HOMs as key factors in predicting J!

We present a roadmap for providing standardised BC measurements, which follows a top-down approach, beginning with SI-traceable measurements of the aerosol absorption coefficient (babs) using in-situ reference methods with a target measurement uncertainty of ≤ 10 % (coverage factor k=2). Two measurement workshops have been successfully conducted, providing essential data to achieve the research goals: 1) two primary reference methods for aerosol light absorption have been tested and validated; these include photo-thermal interferometry and extinction-minus-scattering for at least two different wavelengths. 2) MACBC has been determined for different aerosol mixtures including bare BC, coated BC and externally mixed BC.

This study presents the first experimental analysis of the thermal response time (𝜏) of single aerosol particles using multi-frequency photothermal interferometry (nω-PTI). Optically trapped tetraethylene glycol droplets were excited by a modulated infrared laser, and their frequency-dependent photothermal response was analyzed. A theoretical model was developed to separate the frequency-dependent particle temperature from the effects due to thermal wave propagation and the interferometric detection. Results showed good agreement with simulations for particles between 2 and 5 µm. The study highlights nω-PTI as a promising method to retrieve optical and thermophysical properties and analyze heat transport in the Knudsen transition regime.

Fine particulate matter (PM) poses significant health risks, necessitating accurate monitoring. Low-cost sensors (LCS) are increasingly used for PM measurement in citizen science and pollution mapping, but their reliability is affected by environmental factors and particle properties. Traditional calibration methods often fail to address non-linearities, prompting the use of Machine Learning (ML) for in-situ calibration. This study leverages the SensEURcity dataset from Antwerp, comparing ML models like linear regression, random forests, and Long Short-Term Memory (LSTM) networks. LSTM outperformed others models, achieving the lowest RMSE (8.79 µg/m³) . Model transferability revealed improved data reliability for deployed sensors across urban areas.

Measuring large aerosol particles in a wide size range is challenging due to sampling inefficiencies above 20 µm. The SwisensPoleno Jupiter addresses this with a three-stage virtual impactor, enabling efficient sampling and single-particle characterization using light scattering, holography, fluorescence, and polarization. A combined sizing approach integrates light scattering (0.5–15 µm) and holography (>10 µm) based on confidence metrics. Validation with PSL beads (0.6–100 µm) shows <6% error for 2–20 µm but larger deviations at detection limits.

Quantifying exhaled aerosol and factors that govern the airborne survival of pathogens are crucial steps in improving our understanding of airborne disease transmission. We will present data from a longitudinal study of the amount of aerosol exhaled by individuals and the correlation with exhaled carbon dioxide. We will show that carbon dioxide in an indoor environment does not necessarily reflect the amount of airborne aerosol and pathogen. In addition, we will show the level of carbon dioxide can impact on the survival of airborne pathogens. Both factors must be considered when implementing effective mitigations to reduce airborne viral transmission.

This research investigated the collection efficiency of small bioaerosols which is Bacillus globigii (B.G.) and environmental DNA (eDNA) of B.G using a novel, wearable membrane-based aerosol sampling device called the Compact Personal Aerosol Sampler (CPAS). Aerosolised bacterial spores and eDNA were collected inside a miniature chamber for the capture, recovery, and quantification of DNA.

Pseudomonas syringae is a common plant pathogen, posing a significant threat to the global crop production. Some strains of P. syrinage can cause frost injuries on plants and influence cloud properties and precipitation through ice nucleating proteins (INpro). The study investigated the mechanisms driving aerosolization and INpro production in the model organism P. syringae R10.79. Aerosolization by bubble-bursting resulted in a higher fraction of INpro-bearing cells after aerosolization (33.2%) compared to before (10.7%). A significant positive correlation between the fraction of viable cells and the increase in INpro-bearing cells after aerosolization indicates that INpro are synthesized de novo.

Bioaerosols, including fungal spores, bacteria, and pollen, impact air quality, health, and climate but are difficult to characterize. To address this, we developed a mass spectrometry-based method combining AMS for bulk composition and EESI-Orbitrap-MS for molecular identification. Laboratory experiments confirmed its ability to distinguish bioaerosols, leading to the development of a mass-spectral library to support field measurements in Switzerland for tracing emission sources and seasonal trends.

Asphalt consists of bitumen and is used as a road pavement layer. Bitumen fumes during road paving is classified as possibly carcinogenic to humans. Paving and milling are processes generating occupational exposure to asphalt fumes, particulate matter, and diesel exhausts. The aim was to characterize occupational exposure of milling and road paving with a multi-metric approach. A field study was performed on millers and pavers, and their exposures were monitored during work with real-time monitors and off-line sampling methods. The pavers had the highest geometric mean exposure to most of the exposure metrics.

Here we present a macrophage assay to assess frustrated phagocytosis upon exposure to high aspect-ratio materials containing critical fibres, specifically designed for testing very thin, low-rigidity nanofibres that may not align with the fibre paradigm. We developed novel aerosolization and continuous sampling methods to load cell culture inserts with a well-defined fraction of single-fibres, allowing a precise control of the administered dose. Fibre-macrophage interactions could be recorded by video microscopy allowing to detect frustrated phagocytosis and estimate fibre rigidity. After the observation period, exposed macrophages and media were harvested for toxicological analysis, including cell viability, pro-inflammatory effects and proteomic profiling.

This study introduces an innovative approach to assess workplace PM10 exposure, analyzing over 100 chemical parameters, including oxidative potential (OP), in a Central Italian foundry. Parallel samplings enabled comprehensive chemical characterization and risk assessment. Source apportionment using PMF identified eight major emissions, with riser removal, sand plant, and core finishing showing the highest PM10 mass and toxicant concentrations, significantly contributing to OP and total risk. Spatial mapping of source contributions allowed for estimating employee exposure risks across different work areas. This study provides methodological support for enhanced chemical risk assessment protocols, linking PM exposure to metabolic and inflammatory processes.

This study investigates the personal exposure of traffic policemen to particulate matter (PM) in a traffic-dense industrial area. Over 15 days, personal exposure to PM2.5 and PM5 was monitored using wearable devices, revealing levels six times higher than WHO’s air quality standard. Ambient air quality data indicated PM2.5 concentrations lower than personal exposure levels, highlighting the influence of occupational factors like proximity to vehicle exhausts. The study also found the highest PM deposition in the respiratory tract's head region, emphasizing the need for better occupational safety measures and stricter emissions controls to protect vulnerable workers.

In this work, we combine our previous quantum chemical work on the contribution of iodine and chlorine to new particle formation into an aerosol model together with new sources of chlorine and iodine. We aim to achieve a better understanding of which chemical species that are important for describing the formation of new particles in the Arctic.

Observations of nucleation mode particles over the Arctic Ocean in summer have been associated with prolonged residence time over the pack ice, suggesting that their source is within the pack ice. In this study, the formation of nucleation mode particles over the pack ice is simulated using an aerosol dynamics model and representative particle size distributions from five Arctic Ocean expeditions. Both nucleation of iodic acid and release of marine biopolymer particles contributed to new particles after evaporation of fog. A sensitivity analysis investigates how iodine emissions, nucleation rates, iodne reactions and number flux of biopolymers affect nucleation mode particles.

Time series of ⁷Be in atmospheric aerosols collected from the Antarctic plateau are employed in the STEAR project to investigate potential Stratosphere-Troposphere Exchange (STE) events. These events are critical due to their rapid and sporadic nature, yet their global mechanisms remain scarcely understood and concern the transport of stratospheric O₃ to the troposphere. This study makes a substantial contribution by analyzing data collected over a prolonged period (February 2022 to December 2024) in a remote region, including Antarctic winter, with high temporal resolution through PM10 sampling every 2-4 days, enabling the extraction of novel insights into STE dynamics.

The Arctic is a sensitive environment with missing information on volatile organic compounds (VOC) and their potential to form aerosols, which can further impact cloud formation. Brown algae are important species in Arctic ecosystems and have been shown to be a source of VOC, with I₂, being an important contributor to particle formation. Very few studies investigate the role of co-emitted VOC to I₂-catalyzed particle formation, and knowledge on these contributions is lacking. Here, we conducted a chamber study to investigate particle formation and their potential to contribute to cloud formation from the VOC emissions of a brown Arctic macroalgae.

Atmospheric aerosols impact air quality (AQ) and human health, with PM concentration being a key metric for regulatory limits. Their vertical distribution influences climate by affecting atmospheric stability. Lidar systems, both ground- and space-based, are increasingly used to complement in situ measurements, such as optical particle counters. This study examines aerosol concentration and atmospheric thermodynamics in Turin, a major pollution hotspot, by integrating data from various remote sensing and surface instruments. The analysis explores aerosol vertical distribution, temperature profiles, and precipitation patterns, offering a unique contribution to understanding AQ dynamics in this region, where similar studies are lacking.

The European project MI-TRAP (MItigating TRansport-related Air Pollution in Europe) aims to establish a network of monitoring stations located near transport emission hotspots by employing innovative monitoring devices.

An innovative approach to sampling and measuring PM is based on a new cascade impactor optimized for total reflection X-ray fluorescence (TXRF) providing detection limits in the range of a few picograms absolute mass.

Recently, a first campaign of the MI-TRAP project was scheduled. On-site TXRF measurements enabled the detection of toxic elements at low concentrations in the pg/m³ range. Results will be proven by reference-free synchrotron XRF.

This study evaluated a low-cost sensor (LCS) network across Toronto to enhance understanding of within-city variability of traffic-related air pollution. The network, established in 2023, spanned ~20 locations measuring PM_2.5 and other gaseous pollutants. Field performance was assessed against reference monitors, with relative humidity significantly impacting PM_2.5 accuracy. A time series method effectively isolated traffic signals for CO and NO_x, but less so for PM_2.5. A method placing two nodes on opposite sides of a road was shown to be able to capture and quantify traffic emissions. This work underscores the value of LCS networks in urban air quality monitoring.

We have optimized a method for measuring the singly charged fractions of sub-20 nm particles, building on the setup described in Bello et al. (2024). In this approach, the aerosol charge fraction is determined with an electrostatic precipitator, while a CPC and an electrometer are operated downstream in parallel. Although the method is restricted to particles smaller than 20 nm, it enables charge fraction measurements with relatively low particle losses, offering higher precision than the tandem-DMA setups typically used for the measurement of aerosol charge fractions.

Multiangle Implementation of Atmospheric Correction (MAIAC) AOD from both the MODIS TERRA and AQUA satellites was investigated focussing over Rome (Italy) urban area and its surroundings over the 21-years period (2001–2022). The satellite AOD was firstly validated exploiting long-term dataset of the AERONET Rome-Tor Vergata station. Interesting results were obtained concerning the influence of geometrical configuration of the satellite acquisition and the aerosol predominant mode (fine and coarse) on the accuracy of the MAIAC AOD product. Finally, the investigation on the study area confirms the general decrease of AOD over Rome over the two decades.

The Planetary Boundary Layer (PBL) is the lowest part of the atmosphere, directly interacting with the Earth's surface. Its height (PBLH) is crucial for studying pollution and meteorology but is often difficult to measure. This research utilizes aerosol and Doppler wind lidar data to analyze PBLH evolution across South Italian ACTRIS stations. Various gradient-based and wavelet transform algorithms are applied to lidar data, revealing consistent trends with some deviations during transition periods. Additionally, wind speed and turbulence analyses using Doppler lidar enhance PBLH retrieval accuracy. The study provides valuable insights into PBLH variability across different seasons and atmospheric conditions.

Atmospheric aerosol scattering and absorption wavelength tendencies of AERONET level 2.0, version 3 data (cloud-screened, quality-assured, and AOD at 440 nm > 0.4 a.u.) of 10 long-term stations across Italy have been evaluated (Holben et al, 1998, Dubovik et al, 2002). By using an optical typing approach, the means of Scattering Angstrom Exponent (SAE) versus Absorption Angstrom Exponent (AAE) between 440 - 675 nm of all stations have been categorized in the following aerosol dominant types: dust, dust/OC mixture, dust/EC mixture, coated particles, mixture, OC, EC, and OC/EC mixture (Cazorla et al, 2013).

In this work, aerosol attenuation coefficients from Aethalometers (AE33, AE36S) and aerosol light absorption coefficient measured off-line by polar photometry at five wavelengths (using PP_UNIMI, University of Milan) were compared at different wavelengths. The samples refer to two Arctic cruises carried out in summer 2024 on different research vessels (Oceania - IOPAN and Polarstern - AWI).

This allowed to determine experimentally multiple-scattering enhancement parameters for the Aethalomethers, evidencing instrument- and wavelength- dependence.

Finally, a comparison with the results obtained at high temporal resolution using the approach described in Ferrero et al. (Sci. Total Environ., 917, 170221) was carried out.

This study assessed children's exposure to particulate matter (PM1, PM2.5, PM10), ultrafine particles (UFP), and black carbon (BC) in indoor and outdoor environments (schools, homes, and gymnasium) in Lisbon. PM2.5 exposure was higher during the cold season, likely due to increased outdoor pollution and poor ventilation. In schools, PM2.5 levels increased during class hours and cleaning activities, while in homes, peaks occurred during cooking and cleaning. Indoor concentrations often exceeded outdoor levels, highlighting the significant impact of indoor activities on daily exposure to air pollution.

Air pollution impacts children's health, with ultrafine particles (UFPs) posing significant risks. As part of the InChildHealth project, monitoring campaigns in elementary schools across seven European cities assessed indoor air quality and children's exposure. This study presents data from Athens, Lisbon, and Essex, where real-time UFP number concentration and size distribution were measured inside five classrooms per city using Partector 2 Pro. Concurrent outdoor monitoring was performed. Initial results showed strong indoor-outdoor correlations, with ventilation and indoor activities influencing UFP levels. Indoor and outdoor UFP size distributions were analyzed to investigate mechanisms and indoor activities associated with increased UFP levels.

Raising awareness among businesses and institutions on the topic of indoor air quality requires scientific data and analysis models of a dual nature: 1) epidemiological and 2) economic.

The work quantifies the reduction in time spent in good health due to indoor pollution an turns it into the economic impact in terms of external costs.

Considering all the costs over the whole Italy, the indoor air PM pollution in schools and hospitals ranged between 54-106 billion of € accounting up to 5% of the Italian Gross Domestic Product (GDP). Therefore, treating indoor air means drastically reducing these costs.

Climate change affects indoor air quality through changes in ambient temperatures and pollutant concentrations, indoor chemical reactions and occupant behavior. This work applied the IAQCC model to examine the long- and short-term indoor particle concentrations in a German residence under the SSP5-8.5 scenario by 2100. Results show that temperature rise leads to increased formation of secondary organic aerosols via the limonene ozone reaction. However, this increase is compensated by future decreases in outdoor PM_2.5 levels. Ozone events and Sahara dust storms can significantly increase indoor particle concentrations. Preventive measures are needed to reduce indoor air pollution risks.

This study investigates the atmospheric chemistry of Myrtenal, a first-generation terpene oxidation product from α-pinene. Using an acoustic levitation system coupled with Raman microspectroscopy, we tracked the chemical composition and morphology changes of Myrtenal droplets exposed to ambient humidity. At high relative humidity (80%), rapid chemical transformation occurred, suggesting water's role in the reaction, with slower transformations at lower humidity. Bulk experiments confirmed similar transformations, with faster reactions at the particle scale. These findings reveal oligomerization of Myrtenal rather than microsolvation and emphasize the importance of particle surfaces in facilitating these reactions.

The partitioning of organic aerosol components between gas and aqueous phases depends on Henry’s law constants, yet experimental constraints remain limited. We present a novel method that combines volatility-based fractionation with aqueous solubility measurements to determine their distribution. Applied to SOA from the a-pinene ozonolysis, this approach estimates Henry’s law constants within the Volatility Basis Set framework. Most SOA components with C* in the 10–100 µg m⁻³ range exhibit moderate to slow deposition, while only lower limits are determined for the most volatile SOA (C* = 1000 µg m⁻³). These results enhance SOA removal processes in chemical transport models.

Aerosols originate from natural and anthropogenic sources, with sizes ranging from a few nanometers to a few micrometers. Aerosols significantly impact human health, climate and the ecosystem. The acidity of aerosols modulates nearly all of their properties and processes, yet it has remained virtually unconstrained for decades. The objective of this study is to design and test a non-invasive strategy for monitoring the pH of aerosols. The methodology is based on the deposition of aerosols on functionalized pH-sensitive filter surfaces that get protonated in acidic conditions resulting in structural variations that exhibit distinct Raman fingerprints which is monitored via Raman/SERS.

Aging processes of organic aerosol particles can significantly alter their physicochemical properties, such as viscosity and hygroscopicity, thereby affecting the Earth’s energy budget and climate. Currently, it is not known whether any synergistic effects exist between photolysis and ozonolysis. In this work, the water diffusivity and hygroscopicity of aqueous trans-aconitic acid particles are measured after aging using Electrodynamic Balance set-up. Preliminary results indicate two orders of magnitude increase in viscosity after aging with UV and ozone simultaneously and with UV alone up to 60% mass loss, followed by viscosity reduction upon further UV-aging. Hygroscopicity did not change significantly after aging.

With accelerated warming in the Arctic, dust emissions from expanding glacial outwash plains could impact cloud formation and radiative transfer, but high latitude dust sources remain poorly characterized. We present ice nucleating particle (INP) experiments from samples collected in glacial outwash plains in southern and western Greenland, including surface sediment sample transects and atmospheric filter samples. Surface sediment samples show comparable ice-active mass site densities to other high-latitude sites, exceeding typical desert dust, and variability in ice-activity is likely linked to total organic carbon content. These findings provide new insights into INPs in glacial outwash plains, with possible climate implications.

Aerosols from the natural sources of air pollution reduce air quality at high latitudes. Many extreme events causing severe air pollution were observed/measured in Iceland, Svalbard and Antarctica. In Iceland, we measured i. tens of severe dust storms when the instruments reached 150 mgm-3, as well as long-range transport from Iceland to Scandinavia, Faroe and British Isle, and Svalbard; ii. at least two Saharan dust with PM10>200 ugm-3, and iii. Black/Organic Carbon haze from burning mosses around the hot lava from the eruption in Reykjanes Peninsula with reduced visibility and smoke smell, particles>1 µm. PM1 mass concentrations exceeded 25 µgm-3.

This study investigates the impact of Light Absorbing Aerosols (LAAs) on atmospheric heating rates (HR) in the Arctic. A novel approach was used to estimate LAA-induced atmospheric HR for the first time at a fixed sampling point, using high temporal resolution measurements performed at Ny-Ålesund through 2022. Our results show a significant decrease in reflected radiation-HR, a decrease in diffuse radiation-HR, and the total HR almost equal to previous estimates.. Additionally, were analyzed both BC and HR sources and species apportionment. This study provides a crucial contribution to understanding LAAs' effects on atmospheric HR and their role in Arctic Amplification.

Measurements were made of refractory black carbon with an extended range, single particle soot photometer, Droplet Measurement Technologies, LLC), at the Pituffik Space Base in northern Greenland, during the summer and autumn of 2024. The SP2XR measures light scattered from particles in the equivalent optical diameter (EOD) range from 100-500 nm, and mass concentration of rBC in the mass equivalent diameter (MED) range from 50 – 800 nm. In addition, an equivalent coating thickness is extracted, calculated from the EOD and MED. Measurements are being compared to a global reanalysis model and atmospheric backtrajectories to determine primary transport pathways.

Comprehensive BC source studies in the Arctic atmosphere require large spatial and temporal scales. High temporal-resolution, one-year-long BC measurements during the MOSAiC expedition in the Central Arctic are expended on simultaneous BC observations at Western and European Arctic sections; the Arctic spatiotemporal BC distribution and episodes of the highest pollution are highlighted. BC origin and main contributing sources are assessed for each location using FLEXPART driven with ECLIPSE-GFAS emission inventories. Combined geospatial view provides the contributions of dominated gas flaring, domestic and transport sectors from populated regions in the cold period and biomass burning from wildfires in the warm period.

Aerosols in cold regions impact climate by altering snow properties and accelerating melting. This study presents direct measurements of particle number fluxes and dry deposition velocities at two Arctic sites: Ny-Ålesund (March–August 2021) and Fairbanks (winter 2022, ALPACA experiment). An eddy covariance system measured ultrafine to quasi-coarse particles. Results highlight turbulence-driven deposition, with friction velocity influencing deposition velocity. Comparison with predictive models shows agreement with Slinn (1982), but current parameterizations underestimate fluxes for 0.5–3 µm particles. Findings enhance understanding of aerosol-snow interactions and improve dry deposition modeling in polar environments.

This study analyzed daily-integrated PM_2.5 speciation data in 2017–2023 beside a major highway in Toronto to determine tailpipe and non-tailpipe emission contributions. Brake wear, road dust, and tailpipe emission sources were resolved using positive matrix factorization. The brake wear mainly came from the highway, while road dust was more widespread. We found that trucks emitted more brake wear particles per vehicle than cars, but overall contributions were similar due to higher car traffic. Road salt, especially in coarse mode, was identified as a significant PM contributor during snow season. This study aids understanding of the real-world impacts of non-tailpipe emissions.

Non-Exhaust emissions have been measured within a large measurement campaign in The Netherlands in 2022. At three locations both the Tyre wear particle (TWP) concentration has been determined using TED-GCMS, and the Brake wear particle (BWP) concentrations using ICP-MS. Both methods were supported by SEM-EDX results. The locations have different vehicle behaviours and road types. Earlier studies in 2012 also measured both TWP and BWP concentrations at these locations, allowing for the comparison of non-exhaust emissions over time. The measurements were size selective, allowing for the comparison of both TWP and BWP particle size distributions in the environment.

This study, part of the MI-TRAP EU Horizon project, employs real-time source apportionment (RT-SA) to analyze particulate matter (PM) pollution in Athens. Using the ACSM-Xact-Aethalometer (AXA) system and SoFi RT software, traffic emissions were identified as the dominant PM source, while secondary aerosols contributed over 50% of the total PM mass. Biomass burning, cooking, sea salt, and dust were also detected. A key advancement was the system’s ability to differentiate non-exhaust emissions, such as brake and tyre wear, based on their distinct temporal emission profiles. These results enhance urban air quality monitoring and support targeted pollution mitigation strategies.

Non-exhaust emissions, particularly from tire wear, are a growing concern in urban air contamination. This study identifies benzothiazoles as key molecular markers, revealing their presence in diverse environments, from urban air to remote sites. While strongly linked to traffic, benzothiazoles also originate from textiles, shoe abrasion, and building materials. Their association with fine aerosol fractions suggests long-range transport and multiple emission pathways. Notably, some benzothiazoles appear to have a biogenic source, further complicating their sources identification. By integrating benzothiazoles into air models, this research contributes to more effective investigation of non-exhaust emissions.

The share of non-exhaust emissions is increasing and could become majoritarian. Brake emission is one of major contributor to non-exhaust emission. Brake emissions is source of ultrafine particles and have an impact on human health. Brake emissions are poorly characterized for heavy-duty vehicles in real-world conditions. This study focuses on brake-wear ultrafine particles emitted by a school bus in real-world driving conditions, through on-board measurements. A custom-made stainless-steel emission collection system was designed to measure brake emission. Emissions of gases and certain VOCs during intense braking events was also investigated.

This abstract investigates the impact of a double layered porous asphalt concrete (DLPAC) pavement on PM10 emissions and noise emissions from the road/tyre interaction. Measurements were conducted using a measurement vehicle in traffic at different speeds (50, 60 and 70 km/h), with studded, winter and summer tyres. The results indicated that the studded tyre gave constant emissions, while the non-studded tyres often showed a tendency to decrease where noise emission increased. The results showed that mitigation of PM10 and noise at its source require a holistic approach and consideration of the pavement properties.

We propose the use of tunable-laser PTI (TL-PTI) as a self-calibrating reference technique for quantifying β_abn. In TL-PTI, a wavelength-tunable laser is used to quantify the narrow absorption lines of a gas via direct absorption spectroscopy, providing a reference β_abn,ref in units of Mm^-1. The A-band absorption lines of ambient oxygen at about 760 nm provide a convenient reference. The PTI signal is then calibrated to this β_abn,ref. This gas-PTI signal can then be “switched off” by tuning the laser wavelength away from the absorption lines, so that only particulate PTI signals remain in the background-subtracted signal.

A novel aerosol collection method using suspended liquid films and electrostatic precipitation has been developed to enhance airborne particle detection, including pathogens. The technique employs strong electrostatic fields to capture particles into a liquid film, increasing particle concentration and reducing system losses. An optimised liquid formulation was tested in a chamber with aerosolised microspheres, showing enhanced collection performance with increasing electrostatic field strength. Results suggest that dielectrophoretic forces primarily drive the improvement, with potential applications for sampling low concentrations and recovering viable bioaerosols. The technique shows promise for advancing aerosol sampling methods in various fields.

Illicit substances pose a significant threat to EU public health and security. Conventional surface sampling methods have limitations, prompting a new approach: collecting airborne fractions using an aerosol device. Integrating this with a novel detection device enables analysis via spectroscopy and mass spectrometry, providing a complete characterization. This innovative method enhances detection of illicit substances, streamlines border security processes, and reduces risks associated with handling hazardous materials. It offers a more effective and efficient solution for pre-screening at critical checkpoints, such as customs, airports, and postal services, improving overall security and public safety.

Nanoparticles exhibit complex shapes, influencing properties like bioavailability, toxicity, and reaction kinetics, necessitating detailed size and shape characterization. Conventional methods measure equivalent sizes (e.g., aerodynamic or mobility equivalent diameters) using devices like DMA or APS. Comprehensive analysis requires multidimensional distributions of particle properties. The Centrifugal Differential Mobility Analyzer (CDMA) addresses this by simultaneously classifying particles based on electric and centrifugal fields. It enables two-dimensional property distribution measurements of aerodynamic and mobility equivalent diameters. Results show robust measurements of silver aerosols, highlighting shape factors and multidimensional particle characterization.

The Aerosol InfraRed Monitor (AIRMon) is a novel instrument for near real-time chemical characterization of particulate matter using IR spectroscopy. The AIRMon integrates patented aerosol collection with automated IR measurements, providing quantitative data on organic functional groups and inorganic components. It utilizes an IR-transparent substrate to overcome previous limitations, granting access to previously unavailable spectral regions. This contribution presents detailed calibration analyses and compares AIRMon measurements with other established techniques. Field data from two ACTRIS sites and laboratory measurements of biomass burning emissions are discussed, demonstrating the AIRMon potential for improved air quality monitoring in real-world settings.

Atmospheric trace gases exhibit diverse chemical properties that challenge comprehensive analysis. We introduce Multi-Pressure Chemical Ionization Mass Spectrometry (MPCIMS), integrating high‐ and low‐pressure ionization in a single instrument to quantify volatile precursors and their oxidation products from one gas stream. By incorporating uronium as a reagent, MPCIMS achieves ultra‐sensitive, humidity‐resilient ionization—making uronium a promising positive mode CIMS reagent of choice. Demonstrated in laboratory experiments with a‑pinene, our approach captures the full spectrum from volatile precursors to highly functionalized products, offering comprehensive sensitivity and simplified operation for gas phase measurements to study secondary organic aerosol formation.

Current understanding suggests that the intrinsic properties of freshly nucleated particles critically determine their early growth behavior and potential to reach sizes where they can serve as cloud droplet formation seeds. In this contribution, we present our recent work of theoretically exploring the growth and hydration mechanisms of atmospheric clusters. Sulfuric acid and ammonia clusters will be focused, as they are established as the most prevalent drivers of NPF in many regions due to their strong binding properties and high atmospheric concentrations.

Better understanding of atmospheric sulphur chemistry is key to better modelling and predictions of new particle formation. This presentation will discuss the use of ab initio (DFT) calculations paired with metadynamics simulations to understand reactions in systems of SO₃, H₂O and atmospheric acids, in particular the branching fraction between production of sulphuric acid versus other organosulphates which have been recently measured experimentally. We also hypothesize the formation of new, hitherto unexamined complex organosulphates in the atmosphere.

In our study, we employ semi-empirical molecular dynamics (SEMD) at the GFN1-xTB level to investigate monomers sticking onto freshly nucleated particles, including combinations of sulfuric acid and various amines. Our results reveal that neglecting long-range interactions underestimates the number of collisions leading to sticking. By comparing SEMD and all-atom force field simulations, we find similar enhancement factors, although discrepancies appear at lower collision velocities. For systems with larger effective masses, where such velocities are more prevalent, we would expect the two methods to diverge.

Atmospheric aerosols contain diverse organic compounds, the majority of which remain uninvestigated. Quantifying their effect on aerosol processes depends on properties like the glass transition temperature (T_g). Molecular Dynamics (MD) simulations were carried out to predict T_g for various compounds, considering carbon and oxygen content, functional groups (-COOH > -OH > -CO), and molecular architecture (cyclic vs. linear). T_g increased with carbon number and was consistently higher in cyclic structures. A parameterization was developed based on the MD predictions and was evaluated against experimental measurements. A leave-one-out evaluation approach was utilized, providing insights into the contributions of various molecular features.

Aromatic hydrocarbons are prolific contributors to secondary organic aerosol (SOA). It is known that this contribution is multi-generational, where every oxidation step produces more reactive aromatics, each with successively larger contribution to SOA. However, our understanding of the underlying autoxidation mechanisms that produce low-volatility products is limited, preventing us from quantifying this SOA contribution. This work resolves this using quantum chemical calculations and targetted experiments. We show that a previously unknown geminal diol intermediate plays a key role in the autoxidation of multi-generation aromatic products. This mechanism will significantly reduce the current uncertainties in the contribution of aromatics to SOA.

I present an overview of new computational/theoretical results concerning branching points in the gas-phase oxidation chemistry leading from precursors (hydrocarbons and other VOCs emited to the air) to polytunctional low-volatility products relevant to aerosol formation.

Pirmary and Secondary emissions from Euro6 vehicles are here presented. Diesel cars were characterized by the emission of high quantities of NOx and low quantities of black carbon (BC). The diesel passenger car exhibited very low VOCs emission factors (EFs) compared to the diesel commercial vehicle, especially during the cold urban cycle. On the contrary, gasoline Euro6 vehicles emitted low quantities of NOx, but high BC and VOCs, particularly during the cold start of the engine. Both gasoline vehicles were characterized by high monoaromatics EFs. Results will be discussed in term of technology and fuel type.

This study examines direct particle emissions and secondary aerosol formation from three Euro 6 light-duty vehicles: a gasoline vehicle with a particulate filter, a diesel vehicle with a particulate filter, and a CNG vehicle without a filter. Measurements were taken during repeated 1-hour driving cycles. Results showed the highest direct emissions from the CNG vehicle and the highest secondary organic aerosol formation from the diesel vehicle. The study highlights the need for further research on unregulated emissions, particularly for Euro 6 CNG vehicles, to better understand their impact on air quality and human health.

This study explores the influence of fuel, engine technology and aftertreatment systems on the secondary aerosol formation potential from exhaust emissions by light-duty (LD) traffic.

Since 2022, several European countries have added a particle number (PN) test in the PTI of diesel vehicles equipped with DPF, the so-called PN-PTI test. This study examines five different testing procedures for PN-PTI testing of gasoline vehicles and compares PN-PTI emissions with type-approval PN emissions tested with the worldwide harmonized light vehicles test cycle (WLTC).

Ultrafine particles (UFP) and gaseous pollutants emitted from vehicle exhausts are major contributors to air pollution in urban areas. In the EU, the number of solid exhaust particles is regulated for on-road type approval of vehicles by testing real driving emissions (RDE) using portable emissions measurement systems (PEMS). However, compared to reference instruments used in laboratory testing, PEMS have larger measurement uncertainty due to simpler design, while metrological validation of PEMS is currently lacking. This work studied the performance and uncertainty of PEMS in laboratory and RDE test to underpin the current and future conformity factors.

This study presents an updated emissions inventory for Thessaloniki, Greece, focusing on particulate matter emissions from road transport. Using high-resolution vehicle speed data, spatiotemporal emission profiles were developed and compared with static ones. Results show reduced emissions during summer months and distinct diurnal peaks, especially in the city center and eastern residential areas, contrasting with static profiles. Both inventories are integrated into an air quality modeling system to assess their impact on aerosol concentration simulations, highlighting the importance of dynamic traffic data in urban air quality management.

Recent advancements in low-cost sensor (LCS) and Internet of Things (IoT)-based solutions have enabled real-time monitoring of PM and other pollutants, addressing the limitations of traditional monitoring methods. However, calibration with reference equipment is essential.

This study conducted a monitoring campaign in nine classrooms (171 monitored classes) at a high school in inland Portugal. LCS-equipped monitoring boxes measured PM_2.5, PM₁₀, CO₂, VOCs, temperature, and relative humidity. The results demonstrate that LCS technology can provide extensive and successful air quality monitoring without disrupting teaching, and highlight that PM thresholds are often exceeded in this microenvironment.

The TownAir project investigates air pollution in two Irish towns, where fine particulate matter (PM_2.5) from domestic heating, traffic, and industry poses health risks. In Enniscorthy, winter monitoring revealed frequent exceedances of WHO guidelines, with concentrations up to 200 μg/m³. Using an ACSM and aethalometer, we identified organic aerosols (OAs, 52%) and equivalent black carbon (17%) as major PM_2.5 components. PMF analysis attributed most OA to residential combustion, while traffic emissions and secondary formation contributed smaller fractions. A follow-up campaign near Northern Ireland and comparisons with Dublin aim to inform strategies to reduce emissions and improve air quality in Ireland.

Water-soluble inorganic ions (WSIIs) were determined in HS atmospheric aerosols across nine size fractions. Both PM and WSIIs reached peak concentrations in winter, with autumn and winter concentrations higher than those in spring and summer. Individual WSIIs exhibit distinct size distribution characteristics The size distribution patterns of WSIIs highlight their crucial role in PM formation and suggest that both natural and anthropogenic sources contribute to their presence in the atmosphere. The seasonal variations in size distribution underscore the importance of meteorological conditions and emission sources in shaping aerosol characteristics.

A novel methodology is employed to investigate the impact of particle-specific features on resuspension, partnering a quadrupole electrodynamic trap for controlled particle fabrication and deposition with a small-scale 3D printed wind tunnel. The resuspension behaviour of two distinct particle morphologies featuring cubic structures were investigated and the resulting resuspension efficiencies demonstrate the challenges of resuspending non-spherical particles. Additional high optical and temporal resolution measurements of particle detachment were recorded with high frame rate imaging to analyse particle orientation, particle-surface contact and particle rotation during resuspension. Together these two methodologies advance our understanding of non-ideal resuspension phenomena.

We have performed flow reactor investigations of three cyclic hydrocarbon autoxidation reactions under several short reaction times. A rich variety of oxidation products were recorded with several chemical ionization mass spectrometric methods.

E-cigarettes are marketed as safer than tobacco, but their cardiovascular effects remain unclear. Our study examined the impact of e-liquids and aerosol condensates with different PG/VG ratios, nicotine levels, and flavors (cinnamon, menthol, tobacco) on human aortic smooth muscle cells. Cytotoxicity (LDH release) and pro-inflammatory response (IL-8 production) were measured. Aerosol condensates, especially with cinnamon and high power settings, induced significant cytotoxic and pro-inflammatory effects. E-liquids had milder effects, suggesting that thermal degradation amplifies toxicity. These findings highlight the role of flavors and their degradation products in the cardiovascular risks of e-cigarettes.

We compile more than 200 MAC_BC values from 63 studies and explore the effects of sampling location, study duration, instrumentation (photometers, photoacoustic; mass concentration (CBC) from thermal-optical analysis, or SP2), measurement wavelength, thermal–optical protocol. The data show that photoacoustic measurements of MAC_BC were consistently higher in remote relative to urban environments, indicating Eabs>1 in remote environments, as expected. This trend was not evident for filter-based measurements, and few other clear trends could be identified in general. Notably, wavelength-dependent trends were not evident. Our results do not support the use of simplistic generalizations or assumptions about MACBC in the atmosphere.

This study investigates the role of tricarboxylic acids in new particle formation (NPF) within secondary organic aerosols (SOA). Using quantum chemical methods, we examined three tricarboxylic acids - carboxyheptanoic acid (CHA), 3-methyl-1,2,3-butanecarboxylic acid (MBTCA), and pinyl diaterpenylic ester (PDPE). The results suggest that these acids can act as organic nucleators in combination with sulfuric acid (SA) and bases like ammonia or amines. Our results show strong clustering interactions, indicating that acid-base interactions remain crucial even with organics present. Further research using the Atmospheric Cluster Dynamics Code will explore the importance of these tricarboxylic acids for NPF in more depth.

Biofuels can emit ultrafine particles with distinct features compared to conventional fossil fuels. In this work, coagulation of soot nanoparticles was experimentally and numerically investigated using an atmospheric simulation chamber. Nanoparticles were produced in a laboratory flame of ethylene and ethylene/ethanol mixtures. Simulations based on Smoluchowski equation show that ethylene-flame particles coagulate with an enhancement factor β=2.2, while a larger β=2.6 is found for ethanol-doped flame. Fractal dimension optimization with a fixed β=2.2 also shows good agreement with experiments. These differences point to distinct surface functionalities potentially impacting particle-particle interaction or differences in particles' fractal properties to be further investigated.

The process of drying suspension droplets includes two stages. The first stage starts when a slurry droplet is injected into a drying chamber, while the second stage begins when solid particles form an agglomerate. In this study, we developed models of convective heat and mass transfer of an acoustically levitated slurry droplet that evaporates in an atmosphere of air, water vapor, and soluble gas. It has been shown that the drying rate increases in the presence of active gas. We also found that drying time increases with increasing frequency and decreases with increasing sound pressure of the applied acoustic field.

People usually practice outdoors, thus exercising in the ambient environment becomes another proxy for human health hazard. It is generally accepted that there is a trade-off between air pollution and exercise, which relates to a threshold beyond which the benefit of exercising becomes negative.Τhe present work investigated the personal dose received by trainees during exercise in the outdoor environment. Dosimetry simulations were performed for different levels of physical exertion and particle mass concentrations for males and female trainees.

Biomass burning (BB) contributes significantly to atmospheric aerosol through primary emissions and secondary organic aerosol (SOA) formation during aging in the atmosphere. One crucial parameter for SOA formation and properties is the availability of NOx. Thus, the OH oxidation of BB emissions was studied under varying NOx levels. Burning experiments of different fuels were performed in a residential heating stove and the resulting emissions were diluted and introduced into an atmospheric simulation chamber. Aerosol mass spectrometry was used for a detailed analysis of the organic aerosol phase, showing changes in aerosol oxidation state and composition at different NOx levels.

Exposure to indoor-generated aerosols is a public health concern, yet they remain underexplored compared to ambient pollution. We performed smog chamber experiments at the Manchester Aerosol Chamber to investigate how photochemical ageing influences the oxidative potential (OP) of aerosols from cooking, cleaning, and candle burning. Using high time-resolution instruments for measuring OP, we found that photochemical ageing elevates aerosol mass and OP on both a per-volume and per-mass basis. Once photochemistry ceased, OP decreased by about 40% within an hour, revealing the rapid decay of short-lived OP-active species and underlining the dynamic toxicity of indoor-generated aerosols.

Brown carbon (BrC) aerosols were explored in the northernmost megacity in China during two agricultural-fire-impacted seasons. Agricultural fires resulted in distinct peak in BrC's light absorption spectra at 365 nm, and enhanced the mass absorption efficiency of brown carbon (MAE). The enhancement was more efficient by fires with higher combustion efficiencies. After taking CE into consideration, Fire impacts on MAE showed converged patterns for different seasons. The presence of the ∼365 nm peak also complicated the determination of absorption Ångström exponents (AAE). The ~365 nm peak became much less significant during the day, likely due to photobleaching of the relevant chromophores.

The lockdown held due to the COVID-19
pandemic in Wuhan, Central China, potentially improved
the air quality, from 23rd January to 24th March of 2020.
Daily observations of total suspended particulates (TSP)
in an urban area of Wuhan were performed to compare
9 water-soluble inorganic ions (WSIIs, Na+, K+, Mg2+, Ca2+,
NH4+, F-, Cl-, NO3-, SO42−) and secondary inorganic aerosol
(SNA, SO42−, NH4+and NO3−) reaction mechanisms during
the pre-lock and the lockdown episode.

A model for aerosol typing based on optical AERONET measurements is presented. It uses two main optical properties retrieved at several wavelengths by CIMELs of the network: the Single Scattering Albedo and the Angstrom Exponent. It is obtained by a Machine Learning methodology. It is then applied to the data of CIMEL in Limassol (Cyprus). we found the relative presence of various aerosol types in there. To cross-validate the ML method we use the optical data of a collocated depolarization Raman Lidar. the two have also been used to obtain a climatology of other optical properties from AERONET and Lidar.

In Italy, domestic heating uses often wood (17%) and pellets (7.3%) and in most cases (about 70%), conventional fireplaces or stoves are still used.

This study investigates the impact of different types of stoves on local air quality in two different areas of Lazio Region in central Italy (Rome and Sacco Valley) analyzing existing datasets of PM chemical characterization.

The results highlight the importance of the role of different types of biomass heating systems and suggest that further investigations can provide important information for adopting best practices to reduce harmful effects on health and environment.

We present an analysis of the suspension of small, electrified solid particles in a gas.

This study evaluates the impact of thermal conditions on emissions from heated tobacco products (HTPs) using a custom experimental heating device. HTPs operate below combustion temperatures (~300 °C), but combustion onset and soot formation were observed at 400 °C under ambient conditions. A catalytic stripping (CS) system was used to isolate solid particles from volatile emissions. Advanced measurement techniques analyzed particle number, soot mass, and gas concentrations. Results confirm that thermal degradation dominates below 400 °C, while combustion occurs above this threshold. These findings enhance understanding of HTP emissions and inform strategies to minimize harmful byproducts in tobacco heating systems.

We investigated the role of microbial components in the inflammatory potency of Saharan dust (SD). On the basis of the microbial composition of SD microbial cocktail, composed of Gram-positive and Gram-negative bacteria and fungi were prepared. The SD was then tested in a co-culture model of A549 lung epithelial cells and THP-1 macrophages in quasi air liquid interface exposure conditions. Heat-inactivation of SD abrogated the increased secretion of IL‑1β and IL-8, and this could be restored upon addition of microbial mixtures to the heat-inactivated SD. Our results support importance of microbial constituents in the inflammatory effect of SD.

This study inverstigates the resuspension of microparticles submitted to accelerated flows. Existing study on particle resuspension usually omit the transient phase needed to reach the velocity of interest, yet it was shown that resuspension starts before reaching the steady phase. Moreover, turbulence usually appears during the acceleration phase and the onset of turbulence depends on the acceleration parameter. We investigate experimentally how the acceleration affects the flow and thus how it affects resuspension using smooth glass microparticles.

In present work the key role of particle collisions effect during particle resuspension by turbulent airflow for monolayer deposit is investigated using high speed camera and image processing. The experiments are realised in a dedicated wind tunel for velocities between 1 and 3.5 m/s and particle median diameter of 36 µm. Set of particle trajectories are determined to calculate collision frequencies according to surface concentration and particle size distribution.

Ultrafine particles (UFPs, ≤0.1µm) pose significant health risks due to their deep penetration into the lungs, yet they are often overlooked in studies of air pollution. 7-year data from Athens, Greece is analyzed to calculate the lung deposition surface area (LDSA), using measured PNSD and ICRP/MPPD models. The majority of UFPs are deposited in the alveolar region, highlighting the potential impact on health. PMF source apportionment identified vehicular traffic as the main contributor (60%) to LDSA. Long-term trends provide insight into urban aerosol exposure, emphasizing the need for targeted mitigation strategies to reduce the health risks associated with UFPs.

The respiratory aerosol pH (above 9) has been proposed as a major driver for the infectivity loss of SARS-CoV-2 viruses and influenza A virus in exhaled aerosols, thus affecting the airborne transmission of respiratory diseases. Despite several studies utilising Raman spectroscopy to quantify atmospherically relevant aerosol pH, there is limited understanding of the kinetics of CO2 partitioning and pH variability within respiratory fluid-relevant droplets. In this work, a method to investigate the HCO3-/CO32- equilibrium in a surrogate respiratory fluid system within sessile droplets is proposed to elucidate the pH evolution of exhaled respiratory aerosol.

Road traffic significantly contributes to ultrafine particles and PM2.5. The impact of volatile organic compounds (VOCs), especially intermediate (IVOC) and semi-volatile (SVOC) organic compounds, on particle mass and number is uncertain due to incomplete emission inventories and simplified chemistry-transport model parameterizations (CTMs). The EASVOLEE project updated the LOTOS-EUROS CTM to better represent organic aerosol (OA) formation and particle size/number from road traffic. This includes the CB7 chemistry scheme, VBS scheme, and SALSA2 module. Future steps involve coupling organic vapors with SALSA2 and using new road emission data to assess road transport's contribution to particle concentrations and PM2.5 over Europe.

The point at which a given assembly of molecules represents a molecular cluster, or a particle
remains ambiguous. In this contribution, we give an overview of our recent endeavours in exploring the cluster-to-particle transition concept using quantum chemical methods.

Ship-based measurements of sea spray aerosol (SSA) fluxes (0.5–47 µm) from 2009–2017 in the Baltic Sea and North Atlantic Ocean revealed lower SSA emissions in the Baltic. Elevated chlorophyll-a levels, indicating higher biological activity, reduced SSA fluxes, especially under strong winds. Wind speed, wave dynamics, and wave age were key factors, with younger Baltic Sea waves generating more SSA. Temperature and atmospheric stability showed weaker correlations. This study provides the first detailed comparison of SSA emissions between these regions, highlighting the need for region-specific models to predict aerosol fluxes and their climatic implications.

Markuszewski P. et al. ACP, 2024. https://doi.org/10.5194/acp-24-11227-2024

Unequal-size nanoparticle coagulation plays a crucial role in atmospheric aerosol processes, influencing cloud condensation nuclei formation, aerosol growth and scavenging through coagulation. This study examines the impact of van der Waals (VDW) forces on coagulation enhancement factors using NaCl as a model aerosol. Theoretical modeling and chamber experiments show that enhancement factors vary with particle size and the size ratio of the coagulating pair, deviating from continuum and free molecular models. Assuming a size ratio-independent enhancement factor introduces minimal error (<15%) when nanoparticles coagulate with larger ones rather than smaller ones. These findings enhance the accuracy of coagulation rate predictions in aerosol modeling.

PM2.5 and PM10 remain key air pollutants in Europe, often exceeding WHO air quality guidelines despite emission reductions. This study investigates size-resolved PM concentrations, chemical composition and PM sources at three sites in Saxony, Germany, comparing 2023/24 data to 2013/15. PM10 levels were lower across all sites, particularly with eastern air masses, suggesting reduced anthropogenic contributions. Carbonaceous aerosols at the traffic site decreased significantly, reflecting changes in the local contribution of this PM source from direct exhaust emissions. These findings provide insights into long-term air quality trends. Detailed source apportionment will help determine changes in the contribution of each sector.

The Positive Matrix Factorisation (PMF) algorithm (Paatero and Tapper, 1994) has been the most widely used receptor model for a long time and has only recently been challenged with new methodologies. The novel Bayesian auto-correlated matrix factorisation method (BAMF, Rusanen et al. 2024) integrates an auto-correlation term emulating real-world pollutant sources time evolution has produced higher accuracy compared to PMF. However, both PMF and BAMF struggle to provide well-separated profiles manifested as mixed time series contributions. This work aims to introduce an sparsity prior called horseshoe regularisation (Piironen and Vehtari, 2017) on BAMF in order to improve profile unmixing.

This study examines the vertical variability of aerosol optical properties from 2018 to 2023 near Ny-Ålesund, Svalbard, using observations at two sites: Gruvebadet (61 m) and the Zeppelin Observatory (475 m). Scattering coefficients were measured using an integrating nephelometer, while absorption coefficients were obtained using MAAP, PSAP, and AE33. Seasonal trends reveal that both coefficients are enhanced during the cold season due to Arctic haze from mid-latitude pollution. Radiosonde data indicate that in winter thermal inversions, Zeppelin experiences higher scattering coefficients. In the warm season, Gruvebadet consistently shows higher scattering and absorption when Zeppelin is cloud-surrounded due to scavenging effect.

PMF is widely used to apportion aerosol sources, while current PMF techniques still struggle to adapt to changing source profiles over time. This study proposes a new method that combines PMF with machine learning to dynamically determine the number of sources, leading to more accurate source identification and quantification. Tested on European datasets, the method showed potential to improve PMF results via better-separating sources like cooking activities, and biomass burning. Wider adoption of this approach promises to enhance air quality models, health assessments, and policymaking by providing a clearer picture of PM2.5 sources in diverse environments.

Fifteen years of long-term measurements at an agricultural site in Switzerland revealed trends in nitrogen deposition and aerosol chemistry, complemented by high time-resolution observations. Aerosol pH was lower in summer due to meteorological factors, while NH₃ buffering prevented an expected pH increase despite declining SO₂ emissions. HNO₃ partitioned into particles at night, whereas NH₃ remained in the gas phase, regulated by high aerosol pH. Seasonal variations in dry deposition showed faster nitrate removal in summer, while ammonium consistently deposited rapidly. These findings highlight the complex interactions governing nitrogen deposition and aerosol acidity, informing strategies for air quality management.

Our results show that conducting experiments in a 19 m³ atmospheric volume comparable to real-world indoor environments, combined with the use of a mucin mixture to simulate human respiratory emissions, significantly increases the required UV dose for effective genome copy reduction compared to studies using small-scale reactors. These findings are crucial for designing effective UV-based air disinfection systems, as they provide more realistic dose requirements necessary for mitigating airborne virus transmission in indoor spaces.

The study investigates air pollution mitigation using a green barrier along Viale Fulvio Testi, a high-traffic area in Milan, within the “TESTI” project framework. Preliminary data collection measured PM10, PM2.5, PM1, black carbon, and gaseous pollutants using various instruments. Results showed peak pollution levels during rush hours, with a PM2.5/PM10 ratio of 0.65 due to traffic-induced resuspension. Vertical and horizontal particle profiles indicated a 20% reduction in ultrafine particles (≤50 nm) behind the vegetation. These findings highlight the potential of urban greenery in reducing airborne pollutants and provide insights for designing effective green barriers in urban environments.

In this work we performed sensitivity tests on a free parameter needed to obtain aerosol light absorption measurements by on polar photometry. We tested aerosol emitted by a moto-generator in an atmospheric simulation chamber and collected in parallel on different types of filters (both fibre and membrane filters). Light-absorption characteristics of emissions by different fuels were investigated (i.e. diesel and HVO available in petrol stations).

After measurement optimisation, the role of particle size distribution on Ångström Absorption Exponents (AAE) was experimentally investigated and the results were corroborated using discrete dipole approximation simulations considering different geometric assumptions.

Mineral dust is one of the key players in the Earth’s atmosphere. Dust spans a large size range of particle diameters from 100 nm to more than 100 µm. Owing to the negligence and difficulty in measurement, few information is available on the super-coarse and giant dust size range. We collected deposition samples from field campaigns inside Saharan, Arabian and Arctic dust sources and analyzed them by electron microscopy for size and composition. We present size distributions along with particle composition, e.g. minor compositional differences between Arabian and Saharan dust, or coarser particles particular in the Arctic.

In light of climate goals, biomass pellets are promoted as renewable energy sources, yet their combustion may emit harmful pollutants. This study assessed 30 wood and non-wood pellets sold in Poland, revealing major quality inconsistencies—even among certified products. Many failed key standards due to high ash content, poor durability, or contamination. Emission tests showed that especially agro-pellets release excessive levels of PM, CO, NO₂, H₂S, NH₃, Cl₂, SO₂, and HCHO. Statistical models linked emission levels to pellet properties. The findings underscore the need for stricter certification, better labeling, and advanced quality control to ensure cleaner biomass energy and protect public health.

Detailed air quality monitoring in a small settlement Rožďalovice was conducted in February 2024. Measurements were carried out simultaneously at four locations throughout February. The aim of the study was to assess the spatial variability of benzo(a)yrene (BaP) and PM10 concentrations in small municipalities during the heating season. A preliminary evaluation of the data reveals significant differences in PM10 and BaP concentrations between the monitoring sites. The findings provide valuable insights into the limited representativeness of measurements in areas influenced by local heating sources, also known as 'village hot spots.

An ambient measurement campaign was conducted in an urban background site in Ljubljana (Slovenia) during winter 2024/2025. The aim was to determine the influence of coating on absorption enhancement of black carbon and to investigate the factors influencing the generation of coating. The coating thickness was measured by selecting particle mass using CPMA and measuring rBC with SP2-XR. Photothermal interferometer PTAAM-2λ was used to measure aerosol absorption. First results show a varying mixture of moderately and highly coated particles.

In central Amazonia, aerosol sources, weather, and chemical processes create a highly variable aerosol population. This study connects aerosol optical measurements from the Amazon Tall Tower Observatory (ATTO), at 60 and 325 m heights, to particle composition and sources, characterizing different aerosol populations, assessing their vertical gradients, and associating them with the influence of various emission sources and atmospheric processes. TSI SMPS, AE33 Aethalometers, Ecotech nephelometers, and Aerodyne ACSM monitors were continuously operated at 60 and 325 meters in height. The results show a complex mixture of biogenic sources with organic aerosols from VOC oxidation.

Through the CELLOPHAN project indoor airborne particulate matter (PM) with special focus on micro-nano particles (MNP) emitted by different workplaces has been investigated and analysed by different techniques. Optical particle counters (OPC) were employed to detect particle concentrations, whereas filter PM samples were analysed by Electron microscopy and microanalysis (SEM-EDS). Three different site types were considered for each workplace in order to represent different exposure conditions (direct emission, average exposure, office). Results of particle size and number concentration obtained with different techniques were cross-compared and some preliminary results are reported in this contribution.

This study proposes high-resolution daily maps of PM_2.5 and PM₁₀ concentrations covering the Italian territory from 2021 to 2023 at ~1 km spatial resolution. The work uses machine learning models trained on data from over 300 monitoring stations combined with spatial and spatiotemporal predictors such as land cover, human presence, elevation, atmospheric state, and aerosol optical depth. Among the evaluated models, Ensemble Bagged Trees explained up to 67% of PM variance. The SHAP analysis identifies key predictors impacting the PM variations. These findings improve air quality assessments and policymaking by increasing understanding of PM variability and its underlying causes.

The Helmos Hellenic Atmospheric Aerosol and Climate Change ((HAC)²) station in Greece (2314 m a.s.l.) is the only high-altitude station in the eastern Mediterranean, suitable for climate change-related studies. Two intensive campaigns with the scope of unravelling aerosol-cloud interactions took place at (HAC)2 station; the CALISHTO campaign during autumn-winter 2021-2022 and the CHOPIN campaign during autumn-winter 2024–2025. This study establishes a set of metrics for identifying the influence of Planetary Boundary Layer at (HAC)2 by a synergy of in-situ and remote sensing measurements and applying a statistical model to test their effectiveness.

PM10 has being sampled in Ny-Ålesund (Svalbard, Norwegian Arctic) since 2010 to assess sources, transport pathways and seasonal variations of pollutants. The latest findings (2022-2024) are here presented. Samples were analyzed for lead content and isotopic composition, evaluating the potential source areas of aerosol. The main contribution of Pb was anthropogenic, with a relevant seasonal trend both for concentration (higher in winter-spring) and geographical origin (Russia in winter-spring, with North American contributions in summer). Preliminary results from the analysis of wet depositions and surface snow samples highlighted the influence of Rain-On-Snow events on the local environment.

The Log C*_eff of a molecule represents an important atmospheric variable. The oxidation of volatile organic compounds creates a complex mixture, making C* determination challenging. Furthermore, SOA can be mixed with inorganic salts, impacting the non-ideality of the aerosols. We have generated SOAs in an atmospheric simulation chamber and determined the C*_eff’s of the underlying SOA with either ammonium sulfate or iron/ammonium sulfate seed aerosols. The presence of iron in the seed exhibits non-ideal interactions resulting in ~x10 decrease in C*, which indicates that knowing the underlying seed composition is important for understanding C*_eff.

Black Carbon is a major contributor to air pollution and climate change. Current techniques using an Aethalometer can differentiate biomass burning and fossil fuel combustion aerosols, but their accuracy is limited by assumptions and BC properties. This study explores using Raman spectroscopy, statistical analysis and machine learning to improve BC source apportionment, considering more BC emission sources: diesel, gasoline, and biomass burning. Preliminary results indicate over 95% accuracy in classifying BC sources, providing a promising innovative method for effective air quality management.

It is challenging to distinguishing woodsmoke from other sources. Levoglucosan (specific marker of woodsmoke) is determined on 24-hour filters, lacking high temporal resolution. In this study, we developed an algorithm to automatically identify woodsmoke events from measured black carbon and particulate matter concentrations. The ACSM (estimating levoglucosan from m/Q channel 60) was used to verify the algorithm showing that it performed very well. In an ongoing campaign, we assess whether woodsmoke events can be distinguished by combining BC and PM sensors. By integrating spatially resolved measurements, we aim to provide actionable insights into localized pollution patterns, enabling targeted interventions.

People spend most of their time indoors where they are exposed to a very complex mixture of aerosol. Especially household appliances which produce heat, like toasters, hair driers, and also printers, are prone to generate a large number of particles. Here we present various studies on household and office devices, like a printer, where we used a Catalytic Stripper in combination with other particle measurement techniques to determine the concentration and size of solid and semi-volatile particles. This information could help to develop new mitigation strategies and foster future particle emission regulations for household and office devices.

In this study, we investigated how increased NO_x level within urban plumes affect the evolution of OA volatility at a downwind site. Source analysis was performed on the thermogram data of organic compounds measured by a FIGAERO-CIMS. Increasing NO_x levels mainly affected the SOA formation through gas-particle partitioning, suppressing the formation of low-volatile organic vapors, and thus promoting the formation of relatively high volatile OA. The rise in FIGAERO OA volatility in the afternoon was predominantly driven by high-NOx-like pathway, especially during the urban air masses period.

Polarimetric light scattering measurements enhance understanding of aerosol optical properties, improving aerosol classification and remote sensing validation. However, in situ observations remain scarce. This study presents in situ aerosol polarimetric measurements at Payerne using the IMAP-100 polarimeter to analyze scattering phase functions and polarization-resolved data at different cut-off sizes. Laboratory calibration ensured accurate data processing, and retrievals were performed using the GRASP algorithm. Preliminary results reveal temporal variations in light scattering coefficients and aerosol size distributions. Future work focuses on refining retrievals, integrating multi-instrument datasets, and advancing aerosol characterization techniques to better connect in situ and remote sensing observations.

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.

COVID-19 highlighted the impact of infectious particles on daily life. We explored UV-light-based methods for indoor air disinfection. Therefore, we have tested their efficiency on phages and feline coronaviruses-loaded aerosols, exposing them to UVA and UVC radiation. Thereafter, the aerosols are sampled and quantified genome equivalents (qPCR) and recovered viruses (microscopy). The survivability of all viruses is reduced even with UVA light (53.15 J/cm²) and a clear reduction in genome equivalents is observed under UVC irradiation. Based on that, we outlined currently ongoing experiments focusing on microscopic visualization and the application of UV disinfection in real-world environments.

This study investigates air pollution from waste burning and wood combustion, focusing on rural Hungary. Waste burning, particularly in uninformed communities with poor waste management, emits high levels of particulate matter and toxic pollutants, exacerbating respiratory diseases. Two winter measurement campaigns used advanced aerosol spectrometers and filter analysis to monitor PM and black carbon emissions. Results show extreme pollution levels, however based on the measurement results, it was possible to distinguish between dry wood combustion and illegal waste burning. This research enhances emission source apportionment, supporting targeted air quality mitigation strategies and sustainable pollution management.

Viable particles refer to biological particles, such as bacteria, viruses, fungi, or spores, that are capable of growing, reproducing, or causing infections under the right conditions. In the context of bioaerosols, these particles can remain airborne and potentially spread diseases or impact indoor air quality. Characterizing the viability of airborne particles is therefore very important to accurately analyze infection risk in indoor environments.In this study, we propose a new approach in the real time physical characterization of viable particles in indoor environments with a focus on respiratory particles

Carbonaceous aerosols, comprising 20% to 50% of total aerosol mass, significantly impact climate and human health. This study examines the optical properties of aerosols from different fuel combustion processes, analyzing emissions for particle size distribution and carbon content. Experiments in the ChAMBRe chamber at Genoa University/INFN used a propane-fueled soot generator and a diesel engine running on conventional diesel and HVO. Diesel combustion produced the most light-absorbing particles, with MAC values up to 9.4 m² g⁻¹. Findings highlight the need for accurate correction factors in optical measurements and support real-time monitoring for environmental and workplace safety.

The absorbing properties of aerosols is typically measured using instruments like filter photometers, with the aethalometer AE33 being the most widely deployed. However, FPs are sensitive to scattering, which can lead to measurement errors, especially at high scattering levels. A correction scheme to address this was proposed but requires scattering data, often unavailable in networks. To overcome this, we are testing Machine Learning algorithms using a gradient boosting regressor on a 2023 summer campaign in Granada, yielding accurate compensation results. The model is being expanded to 23 European sites to validate and refine the algorithm and cross-validate with other instruments.

Here we present the results of several experiments, performed at ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research) with the aim to measure the optical properties and size distribution of aerosol generated by combustion of HVO (Hydrotreated Vegetable Oils) and diesel B7 (conformed to EN590).Results in terms of size distribution (NanoMoudi), optical properties (MWAA and BLAnCA) and EC/OC ratio (thermal-optical analyses) at each stage of fresh and aged aerosol will be presented at the conference.

This study analyses PM10 and CO levels from June 2018 to June 2024, as well as the chemical composition of PM10 from 2021 to 2023, to determine source apportionment using the US-EPA PMF5 model. After discounting North African dust apportionment, a 25% reduction in combustion emissions is required to meet the 2030 directive’s target. Therefore, it is crucial to maintain, until at least 2030, the measures outlined in the Air Quality Plan of Villanueva del Arzobispo by the Junta de Andalucía, specifically targeting biomass combustion emissions.

This study apportioned the sources of PNSDs by analysing the data collected between January 20^th and March 9^th 2000., during the winter season period of 40 days before COVID19 lockdown. Source profiles, obtained by application of EPA PMF5 software, were interpreted considering the potential regional sources, local sources and the fact that level of air pollutant including PM fractions are variable over the time and depend from a combination of source emission rates and meteorological conditions. It is investigating the influence of on ultrafine particle (UFP) sources to determine the success of the mitigation strategies and to plan future actions.

Air pollution has become a major problem in large urban conglomerates, particularly in megacities. The objective of this study was to investigate the chemical composition of the submicrometric aerosol particles during the intensive campaign of the “BIOgenic emissions, chemistry and impacts in the MASP: BIOMASP+” project. The BIOMASP+ took place at two sites the Matão-IAG (urban forest site) and Reserva Morro Grande (RMG, Atlantic Forest site) from April 22 to May 22, 2023. The PM1 (18 and 5.2 µg.m-3) measurements were performed a using the Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM). Positive matrix factorization was performed on the organic fraction.

Lidar measurements have become essential for near-real-time atmospheric monitoring. At Mount Etna, within the VULCAMED project, lidar observations of volcanic aerosols have been conducted since 2010, initially with a single-wavelength prototype and later with an advanced multi-wavelength system developed. Originally designed to operate in the UV and IR spectral regions, the system was upgraded with VIS channels, improving aerosol characterization. It now acquires elastic and Raman signals at multiple wavelengths, enabling measurements of aerosol optical and microphysical properties. Calibration and validation procedures are required to optimize performance; the implementation and preliminary measurement results will be presented.

We study how estimates of the relationship between air pollution and mortality may be improved with more information on air pollution concentrations or death records, and compare the impacts of improved air pollution data alone versus improved death data alone. We also study the effect of social inequalities by comparing what happens when there is missing data in the majority demographic. Because different groups face different pollution levels, minority data is statistically more informative, offering insights unavailable from majority data alone. This highlights the importance of inclusive data for accurate environmental health assessments.

The combustion of household waste in fireplaces negatively affects air quality, among other factors, due to the increased emission of soot. In this work, various plastic waste types were co-burned with firewood, and legal fuels were also burned separately in a fireplace under controlled conditions. The emission factor of soot was calculated and discussed for the burning of specific waste types.

Major peculiarity of BC pollution and sources are highlighted in Moscow, largest northernmost European megacity, with gas-fueled heating system and absence of residential biomass burning. Upgrade to European phenomenology supports the harmonization of BC measurements allowed for comparisons between cities; two and a half-year mean BC in Moscow urban background is found significantly less than in France, Spain and Greece, and no difference with UB sites in Northern, North-Western, Eastern Europe, and in Netherlands, Germany. Annually average Moscow monthly eBC concentrations characterized by increased values in August and September, different from European UB with prominent winter SF residential heating impact.

In response to elevated PFAS concentrations in soil, water and air in the wider Antwerp region, the Government of Flanders decided in June 2021 to map out the problem and to initiate a coordinated approach and perform extensive monitoring campaigns on a regular basis throughout Flanders. This contribution reports about the results from air monitoring campaigns that were conducted at a range of monitoring sites including industrial, urban residential and rural sites in Flanders, with the purpose to survey and assess the PFAS concentrations and fingerprints in ambient air and deposition.

This study analyzes black carbon (BC) concentrations in Qatar from 2022 to 2024 across urban and background sites. BC levels were highest near traffic-heavy areas and declined over time due to improved urban management post-2022 FIFA World Cup. Seasonal peaks occurred during the hot-humid months, while diurnal patterns followed traffic trends, with morning and nighttime peaks. The ΔBC/ΔCO ratio confirmed diesel vehicles as a dominant source. Comparisons with SO₂ and NOₓ indicated BC's traffic-related origin, while SO₂ peaks suggested industrial contributions. These findings provide insights into BC pollution trends and influencing factors in Qatar's environment.

Two measurement campaigns were performed, in cold and warm periods, simultaneously at two sites, urban and suburban background, about 4.3 km apart, in the area of Lecce (Southern Italy). Daily PM2.5 samples were collected simultaneously on quartz and Teflon substrates by a dual-channel low-volume (2.3 m3/h) automatic sampler. Additional measurements were particle number concentration in the range 0.3-10 μm, using two optical particle counters (OPC), and size distributions in the range 0.01-0.8 μm using two scanning mobility particle sizers (SMPS). Meteorological data were also collected at both stations. Chemical characterization included elemental composition analysis by energy dispersive X-ray fluorescence (ED-XRF).

Indoor air quality (IAQ) is crucial globally and in Europe, where people spend 90% of their time indoors. It is influenced by internal emissions (activities, materials) and outdoor air quality (OAQ), depending on ventilation rates. The ECOSISTER project studies IAQ in a Bologna’s district using low-cost sensors to monitor indoor and outdoor CO₂, PM, VOCs, NOₓ, O₃, and meteo parameters. Preliminary results show a strong impact of outdoor pollution on indoor PM levels and the predominance of indoor VOC sources. The study aims to develop smart solutions to reduce human exposure to pollutants while optimizing indoor comfort and energy efficiency.

This study examines the seasonality of BC and its components related to fossil fuel combustion and biomass burning (BC_ff, BC_bb), as well as the spectral absorptions related to BC and Brown Carbon (BrC) at two regional-background sites in Greece. The first site is at Finokalia, Crete, a well-known measuring station for atmospheric composition in the eastern Mediterranean and the second is located at a continental background site in NW mountainous Greece (ZEP, Kozani). Both stations are mostly affected by regional-background aerosol plumes of different optical and physico-chemical characteristics (continental vs. marine), and are sensitive in detecting long-range transported aerosol plumes.

Absorbing atmospheric aerosol constitutes an essential contributor to Earth’s climate system, since it possesses the ability to absorb solar radiation, affecting radiative forcing. The area of Europe constitutes a scarce context for the investigation of absorbing aerosol, since it is characterized by a vast diversity of emission sources and atmospheric conditions. The current research utilizes a multi-faceted approach, employing ground-based observations combined with chemical analyses, to quantify aerosol properties. The results indicate that absorbing aerosol demonstrates pronounced seasonal and temporal variability, while high absorption coefficients of BC and BrC, appear to be associated with intense biomass burning and residential heating.

As part of the larger Clouds and Precipitation Experiment at kennaook (CAPE-k) campaign, CAPE-k CHEM performed online measurements of aerosol precursor vapors using state-of-the-art aerosol instrumentation deployed for the first time at kennaook/Cape Grim. This abstract describes the motivation, purpose, methodology, and show first results. CAPE-k CHEM ultimately aims to elucidate the sources, transformations, and fate of natural aerosols in the Southern Ocean as well as their effects on cloud properties by incorporating air mass back trajectory analysis, meteorological reanalysis data, and satellite products as well as utilizing statistical tools such as Positive Matrix Factorization (PMF) and machine learning.

The newly developed Laminar-Flow Oxidation Reactor (ILOx), with a total internal volume of 8 liters, enables the simulation of multi-day atmospheric oxidation processes within minutes. Depending on the total flow, typical residence times range from 2 to 16 minutes. A surrounding 480 W UVA LED lamp (365 nm) provides direct irradiation over 72% of the reactor's surface. The outlet is optimized for simultaneous sampling of VOCs and particles. We will present a comprehensive characterization of the ILOx Reactor, highlighting its oxidation potential. The results will be validated through comparison with the F0AM-4.3 model.

Biomass burning (BB) significantly impacts air quality, health, and climate by emitting gases and particulate matter. In the Valencian Community (Spain), around 60 kt of rice straw is burned annually, raising environmental concerns. A recent campaign at EUPHORE chambers (Jan–Feb 2025) investigated gas- and particle-phase chemistry and aerosol aging from rice straw combustion under light and dark conditions. Using advanced instruments like HR-ToF-CIMS, the study identified degradation pathways, including the formation of phenolic, furanic, nitrogen-containing compounds, and other BB tracers such as levoglucosan. This ongoing research provides new insights into BB pollutant chemistry.

Results of experiments conducted at the CERN CLOUD chamber to study the interactions of unipolar small ions and multiply-charged small particles (<10 nm diameter) with large aerosol particles in the CCN size range (50-100 nm). We will report new insights into the impact of electric charge on particle-particle and particle-ion collision rates in unipolar environments.

This study presents long-term measurements of light absorption by atmospheric black carbon (BC) in Northern and Southern Finland, using the PAAS-4λ four-wavelength photoacoustic aerosol absorption spectrometer. The data were compared with MAAP and Aethalometer AE33 measurements to evaluate their accuracy in determining BC mass concentrations (eBC). The study identifies periods influenced by long-range transported combustion aerosols and investigates the variability of the Aethalometer multi-scattering correction factor, C, and its relation to source regions. Further analysis explores BC’s mixing state using light scattering and single scattering albedo (SSA). These findings enhance understanding of BC’s impact on the Arctic climate.

Human exposure to the ultrafine fraction of particulate matter, (UFP), has serious health effects due to their ability to penetrate deep into the lungs. Traffic exhaust emissions are a major source of particulate matter in urban environments.

Volatility is one of the most important physical properties of aerosol particles, as it can provide real-time information on the particle mixing state for UFPs.

This work aims to study the volatility of aerosol particle number. The measurement campaign took place at a traffic site in Athens and compared with those recorded at a suburban research station located at the N.C.S.R. ‘Demokritos’.

The bioaccumulation of metals can increase human health risks through several pathways, including particle inhalation, etc.This study aimed to distinguish lithogenic metal sources from anthropogenic soil contamination caused by dust fallout from smelting operations. Topsoils (28), soil profiles (5), dust fallout (17), total suspended particles (TSPs) (10) were collected around the mining site. Mass concentration of metals (Co, Cu, etc.) associated with smelting activities in the topsoil exceeded their background value found in the deeper layer, indicating anthropogenic contamination. In addition, enrichment factors showed that TSPs reflect recent contamination, while dust fallout and top soils show contamination integrated over time.

Particles emitted by the mechanical braking of commuter trains are part of the non-exhaust particles. The concentrations of these metallic particles with potential adverse health effects are high in confined underground train stations. It is therefore important to understand which component of the braking system, pads or disc, contributes mostly to the emission of particles, in order to design low-emission materials. To this purpose, a mass balance approach has been applied to metals, tracers of the friction materials. The results are discussed and compared to independent measurements of the volume loss of the materials.

The study investigates the toxicity of fine particulate matter (PM2.5) sampled at two sites (urban and urban background) in South Italy, focusing on oxidative stress and cytotoxicity. Both acellular assays (ascorbic acid and DTT) and cellular assays based on A549 cells were used. Most samples showed cell viability inhibition below 20%, some between 20%-50%, none exceeded the 50% value. A correlation between oxidative stress and reduced cell viability was observed. Urban PM2.5 induced higher oxidative stress than suburban samples. The results suggest that the chemical composition of PM2.5, rather than its mass concentration, plays a crucial role in its toxicity.

Different methods to detect Saharan dust events (SDE) based on in-situ aerosol optical parameters or size distribution and on FLEXPART back trajectories are evaluated and compared to CAMS dust products at the high-altitude site Jungfraujoch. The method based on negative single scattering albedo exponent is more efficient in winter but depends on the type of nephelometer and absorption photometer. The method based on the size distribution is more efficient in summer. A 24 years climatology of the SDE hours and mass allows to see a trend toward more dust influence since 2020.

This study focuses on determining emission rates of source-specific black carbon (BC) and organic aerosol (OA) using a combination of source apportionment and atmospheric modeling. Measurements were conducted in Nova Gorica, Slovenia, using an Aerosol Chemical Speciation Monitor (ACSM) and an aethalometer over three months in 2024. A box model approach estimated emission rates by incorporating atmospheric dynamics through planetary boundary layer height inferred from radon measurements. Results showed distinct diurnal patterns for traffic and biomass burning emissions, while secondary OA can be linked to photochemical production and long-range transport.

This study examines the health impact of ultrafine particle (UFP) emissions from a Compressed Natural Gas (CNG) passenger vehicle, despite CNG being considered a cleaner alternative to gasoline and diesel. A Euro 6 CNG taxi was tested under two real-world driving cycles using a chassis dynamometer, with emissions analyzed through Air-Liquid Interface (ALI) in-vitro cell exposure. A549 human epithelial cells were exposed to diluted exhaust, revealing cell mortality, increased cytokine production, and inflammatory responses. The mRDE driving cycle had a significantly stronger impact, indicating that different driving conditions influence emission toxicity and potential health risks.

Experiments were conducted following the beReal test protocol to simulate real-world combustion conditions. A comprehensive physicochemical characterization of gaseous (VOCs, CO, NO_x) and PM phases (mass, size, number, morphology, BC, EC-OC, ions, metals, molecular composition) was conducted, alongside an extended analysis of toxic species (PAHs, nitro- and oxy-PAHs, nitrophenols, carbonyls).

For toxicological assessment, cells were simultaneously exposed to primary and aged emissions. Particular attention was given to determining the PM mass deposited on the cells.Inflammatory markers (Nrf2, NFkB, TNF-a, IL-1b, IL-6, IL-8) and oxidative stress (carbonylated proteins), cell membrane damage (4-HNE), and DNA oxidation (8-OHdG) were assessed.

Available observations suggest that some mountain regions (including Alps) are experiencing seasonal warming rates that are greater than the global land average. The reasons behind the magnitude of climate change in mountains are not entirely clear. However, there are some known mechanisms that can produce enhanced warming rates.In particular light absorbing aerosol absorbs solar radiation and warms the mid-troposphere. Therefore, we carried out a measurement campaign from 1/05 to 31/10 2023 at the Jungfraujoch facility in order to experimentally determine the atmospheric LAA HR in the free troposphere. Preliminary results showed an average value of 0.035 ± 4*10-4 K/day.

The POSEIDON campaign, conducted in September 2024 on Poros, a Greek island downwind of Athens, the capital of Greece, aimed to study the chemical aging of urban emissions. Advanced instruments measured aerosol and gas phase pollutants, while additional measurements were conducted in Athens for comparison. Organic aerosol (OA) accounted for 52% of PM₁, with more-oxidized OA comprising 64%. Aged biomass burning OA (15%) was associated with the more-oxidized OA factor. The study analyzed air mass trajectories, VOC ratios, and OH concentrations to assess oxidation processes. These findings provide valuable insights into the atmospheric transformation of urban emissions.

Firefighters face health risks from air pollutants in fire smoke, classified as carcinogenic. A study in Catalonia (2022–2024) measured exposure using PM2.5, black carbon (BC), and PAHs. Biological samples (urine, nasal mucosa, dried blood) assessed short-term health effects. Torch operators had higher BC and PAH exposure, while line operators faced lower doses but sometimes stronger immune responses. IL-8 levels indicated inflammation, varying by task. Findings suggest task-dependent immune effects and individual susceptibility. Further research on blood and urine samples aims to clarify the link between wildfire smoke exposure and health impacts.

A new paradigm for transport channel-resolved failure mode biosecurity assessment is under research in HE-FARM project. Among the potential channels for transportation of pathogens, aerosols play a key role. In this context the new Counterfog® BIAFTS method (del Álamo, 2022) has been used to sample bioaerosols in a chicken farm at two different heights. Culture of active bacteria and fungi from these samples shows a variation of predominance and ratios of the different species evidencing a fractional soaring of the species. This demonstrates the strong interaction of air dynamics with the aerosolization processes and an example of spatial heterogeneity.

Glycolic acid sulfate, the sulfate ester of glycolic acid, has been detected across many locations in the atmosphere, though its formation mechanism remains unclear. This study develops a method for quantification using ultra-high performance liquid chromatography with a HILIC column coupled to Orbitrap mass spectrometry. Atomizer experiments with glycolic acid and sulfuric acid show that glycolic acid sulfate only forms in the aerosol phase, and not in the bulk phase. Further atomizer experiments and chamber studies aim to shed light on its formation mechanisms and potential relevance to the formation of other organosulfates.

This study examines air pollution caused by the September-October 2024 war in Lebanon. PM2.5 samples collected in Beirut showed a threefold increase in particulate matter near the conflict zone compared to pre-war levels (2018–2021). Gravimetric and PIXE analyses revealed high concentrations of toxic metals (Pb, Zn, Cu, Ni) from weapon fumes and debris, as well as increased sulfur and chlorine from combustion. These findings highlight severe air quality deterioration due to warfare.

Electronic cigarettes (EC) have gained popularity, with the introduction of fourth-generation devices based on e-liquids containing nicotine salts that promise a smoother vaping experience than freebase nicotine. However, the toxicological effects of nicotine salts are still largely unknown. Human lung epithelial cells were exposed to undiluted aerosols of e-liquids containing various ratios of solvents, freebase nicotine, organic acids, nicotine salts, and flavoured commercial e-liquids. Cytotoxicity, inflammation, and oxidative stress, were assessed 24 h after exposure. Results showed that aerosols from fourth-generation devices can cause different toxicological effects, the nature of which depends on the chemical composition of the e-liquid.

In this work we studied the effects of NO_x concentration on isoprene SOA density, oxygen-to-carbon ratio (O:C) ratio, volatility, volatility distribution and vaporization enthalpy. Dark ozonolysis or photo-oxidation experiments of isoprene were conducted in an environmental chamber at varying NO_x concentrations. The particulate phase was analyzed using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Scanning Mobility Particle Sizer (SMPS). A thermodenuder system was used for the SOA volatility characterization.Our results indicate that RO₂ chemistry has a non-linear effect on SOA density, O:C ratio and volatility.

This study presents the first investigation of UFP in Zagreb, Croatia. We studied the influencing factors on physical and chemical properties of UFPs, using the scanning mobility particle sizer during two contrasting seasons (winter and summer 2024). On-line black carbon (eBC) concentrations were measured by aethalometer, while particle size fractions (13 stages; from 10 nm to 32 μm) were collected with an MOUDI impactor and analysed for mass and organic carbon content. Data were correlated with meteorological parameters, biomass burning (BC_bb) versus fossil fuel (BC_ff) contributions to eBC, and NO₂, SO₂, and O₃ concentrations

This study investigates indoor PM_2.5 in new London flats. High indoor emissions, particularly cooking, cause sharp peaks (up to 600 μg/m³), while non-emission periods stay below 50 μg/m³. Outdoor PM_2.5 averages15 μg/m³ with moderate infiltration (0.4–0.5), rendering outdoor contributions negligible. Seasonal variations in ventilation, cooking patterns, and weekend occupancy further influence pollutant levels. Open-plan layouts yield strong coupling between kitchens and lounges, with bedrooms showing relatively lower levels (max 60 μg/m³ even when kitchens peak at 300 μg/m³). Building airtightness also modulates infiltration. Future work will expand to TVOCs and CO₂ for a comprehensive assessment of indoor air quality.

This study explores ice nucleation on copper oxide (CuO) surfaces using Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. Findings reveal that water adsorption is initially dominated by chemisorption at Cu-O sites, followed by multilayer physisorption. Adsorption isotherms and energy calculations (~8.23 eV) confirm strong surface-water interactions, influencing ice formation. Reactive MD simulations highlight dissociative and molecular chemisorption, with water clustering around active sites. These insights improve atmospheric modeling and material design. Future research will refine adsorption models and integrate experimental validation to enhance understanding of heterogeneous ice nucleation and surface wettability engineering.

Particularly during winter, urban areas of the Southeast Europe (SEE) are experiencing some of the poorest air quality globally. It imperative to understand SEE urban air pollution, 1^st locally (emission sources, processing, and the adverse health effects) and 2^nd regionally (transboundary outflow). This presentation will give the results of two major projects centered at supersite in Sarajevo, Bosnia and Herzegovina (BiH). Sarajevo, BiH is an excellent case study for the SEE urban air pollution: it is situated in a basin surrounded by mountains, and during cold winter months, topography and meteorology cause trapping of the pollutants in its basin.

The study analysed atmospheric particulate matter in North-East India during the post-monsoon season of 2023, using SEM-EDX and FTIR to assess morphology, elemental composition, and different functional groups. Particles ranged from 1 to 70 μm, with major elements like C, O, Si, and hazardous elements such as Cr and Fe. Sources were identified using Enrichment Factor, Pearson Correlation, and PCA, revealing dust aerosols are the dominant species. Optical properties were simulated using DDSCAT-7.0, showing higher extinction and scattering efficiencies at shorter wavelengths for non-spherical particles. Shape significantly influenced optical properties, with rectangular particles exhibiting higher light attenuation than spherical ones

Emissions profiles of commercial ships are changing and new studies are needed to quantify and trace these ship emissions from new alternate marine fuels. A research project, PortAIR, took place in the Dublin port area. The analysis of aerosol chemical speciation monitor data using combined organic and sulfate ion positive matrix factorization. idenitified three types of ship fuel emissions: sulfate-rich (S-Ship), organic-rich (O-Ship), and Marine Gas Oil (MGO). Overall, S-Ship and O-Ship plumes were observed frequently and contributed to at least 28%-47% of PM₁, but MGO were somewhat 'invisible' to the scientific and regulatory mass measurements, posing a problem.

Over the past three decades, pollen allergies have increased, possibly due to air pollutants like ozone and nitrogen dioxide modifying allergens such as Phl p 5. These modifications, including dityrosine and nitrotyrosine, influence the allergen's interaction with the TLR4 receptor, a receptor central in inflammation. Ozone exposure only leads to dityrosine formation, increasing TLR4 activity. Nitrogen dioxide exposure results in both nitrotyrosine and dityrosine, also increasing TLR4 activity but less than Phl p 5 after ozone exposure alone. The reaction with peroxynitrite, also causing both modifications, significantly increases TLR4 activity, highlighting the impact of site-specific tyrosine modifications on TLR4 activity.

Istanbul is one of the major metropoles in the world with more than 16 million inhabitants, providing access through motorway, maritime and air transportation between Asia and Europe. These activities represent different pollution sources causing a complex air pollution profile across the province. This is the first study on measuring a wide range of particle number size distribution (10 nm to 10 um) conducted in Istanbul and measured at the urban background, urban and traffic sites in Istanbul using a NanoScan SMPS and Palas for 20 days in summer. Source apportionment analysis showed the main source of particles is traffic.

Given its importance in assessing the health impacts of PM, OP, aligned with information from the sources and composition of PM, can be of extreme importance in creating new directives on air quality. However, the lack of a standard method makes it difficult to compare results and effectively create new legislation. This study aims to test a reference standard for the OP analysis, providing a useful tool for quality assurance and results comparison.

From the perspective of engineering control hierarchy, source control is always the most cost-effective option compared to pathway and receptor control. A novel breath-taking hood has been developed to completely capture respiratory aerosols exhaled by infected people to protect the environment. It could replace negative pressure wards, remove the need for isolation and quarantine, and make city or national lockouts redundant. The source control device demonstrated in the study could revolutionize infection prevention and control.

Understanding aerosol optical properties is essential for assessing their climate and air quality impacts. This study characterizes aerosol absorption and scattering in León, Spain, based on a three-year sampling campaign (2021–2024). Measurements were conducted at urban and suburban sites using an AE33 Aethalometer and an Aurora 3000 nephelometer. Extreme absorption and scattering values were recorded during Saharan dust intrusions and fossil fuel emissions. Findings highlight the relevance of combining optical coefficients to identify aerosol sources, contributing to improved climate models and air pollution management strategies, particularly in urban environments.

This work focuses on the HypnosAIR project approach to assess and reduce air pollutant exposure during sleep, integrating daily AQ exposure characterization (indoor and outdoor microenvironments), and exposure-response analysis. The methodology chosen involves 80 volunteers. A key component of this study was the deployment of portable low-cost sensor monitoring units (MUs) to monitor real-time AQ parameters to characterize the daily human exposure to air contamination. The results obtained so far confirm previous findings from studies conducted by the authors (Ramos et al., 2022), which demonstrate that some IAQ parameters may influence the sleep quality of the individuals.

Measurements of viable, cultivable, airborne bacteria and fungi using passive sampling and culture-based analysis were performed in different indoor environments where children spend their time to assess their airborne microbial exposure. The presented results allow to assess that the airborne microbial contamination indoors depends mostly on different environmental conditions (such as temperature, relative humidity), as well as on activities, such as occupancy and cleaning rates, and ventilation conditions. The bacterial contamination indoors is related to the occupancy rates and the ambient temperature. As the ambient temperature decreases, a reduction in bacterial contamination was observed inside schools.

PAH emissions from cooking significantly affect indoor air quality. In our study a one-month biomonitoring was carried out in Hungarian kitchens using basil (Ocimum basilicum), rocket (Eruca sativa), parsley (Petroselinum crispum) and chives (Allium schoenoprasum). The two main objectives were to follow PAHs accumulation pattern in the kitchen vegetables, and to find out if this pattern can be associated with the different cooking habits (methods: deep fry, pan fry, oven baking, boiling; used materials: lard, butter, oil).

This study examines fine particles (PM2.5) from grilling pork and mackerel, focusing on composition and toxicity. Mackerel grilling emitted more PM2.5, while pork grilling had higher organic carbon (OC). Both generated toxic aerosols, with mackerel showing higher oxidative potential and pork inducing stronger inflammatory responses. Findings provide insights for air quality and health policies.

This study analyzes the levels and chemical composition of PM10 at two monitoring stations of the Air Quality Network of Andalusia in the city of Seville (684k population): Torneo and Príncipes, both significantly influenced by traffic emissions. Sampling was performed between 2021 and 2023. Based on the chemical composition, source apportionment study to PM10 were determined using PMF5. Simultaneously, a study on vehicle flux near both stations under varying weather conditions (primarily wind and rain) was correlated to daily traffic apportionment in order to calculate que equivalence of concentration of PM10 and number of vehicles every day.

The CIAO atmospheric observatory at CNR-IMAA in Southern Italy has been upgraded with an aerosol in-situ observational component, complementing over two decades of remote sensing studies. Located in a Mediterranean-influenced mountainous region, CIAO is ideal for studying natural aerosols like desert dust and volcanic particles. In February 2024, it was accepted as an ACTRIS National Facility, enabling advanced aerosol measurements. Continuous monitoring, starting November 2024, will enhance aerosol characterization, support improved typing methods, and contribute to understanding particle transport. The first-year data will be presented at the conference.

Fine and ultrafine particles affect human health through oxidative stress. This study examines how PM2.5 and PM0.1 composition influences oxidative potential (OP) using aerosol samples from two field campaigns (summertime and wintertime) in Greece. The water-soluble OP of PM2.5 and PM0.1 were compared and linked to their composition and sources. Initial results showed that wintertime PM0.1 composition is strongly influenced by calcium and sulfur, with refractory black carbon contributing 10% of PM0.1. PM0.1 concentration exhibited strong temporal correlation with potassium, indicating significant contribution from combustion-related emissions. Further statistical analysis is needed to clarify these associations and their contribution to OP.

The aim of the research was to determine the air quality in terms of aerosol pollution in selected ports of northern Europe and on transects between them. During the research cruise from Gdynia (Poland) to Bodø (Norway) in the period from June 5 to July 2, 2024, size segregated aerosols samples were collected using the Tisch Environmental TE-6000 high-flow impactor. Aerosol samples were collected in 3 seaports (Bergen and Bodø in Norway and Malmö in Sweden) and at 12 stations located on transects between ports. The aerosol research was supplemented with the analysis of meteorological parameters and air mass trajectories.

Air pollution poses serious health risks, necessitating improved toxicity assessment methods. This study evaluates a novel "Cells-on-Particles" in vitro model for cytotoxicity testing of ambient air aerosols. The nanofibrous polycaprolactone (PCL) platform efficiently captures fine particles while providing a cell-friendly surface. Samples were collected near a high-traffic street, and exposure doses were normalized to platform surface area. BEAS-2B cell viability decreased in a dose-dependent manner, with significant cytotoxicity at 50 µg/cm². The LDH assay confirmed cell damage only at the highest concentration (50 µg/cm²). This platform enables direct cell exposure, providing a rapid and representative assessment of aerosol toxicity.

In this study, a long-term online field measurement (from 2016 to 2019) of shipping emission tracers, i.e., vanadium (V) and nickel (Ni), was carried out at a downwind sampling site (i.e., the Dian Shan Lake (DSL) supersite) which is ap-proximately 50 km from the Shanghai waters. Despite the long distance, the decreasing trend in V concentrations from the phase of DECA 1.0 (5.1 ng m-3) to DECA 2.0 (2.4 ng m-3) reflected a positive response due to the strengthened emission control.

Volatile Organic Compounds are airborne pollutants of concern extensively investigated by the International scientific community for the potential adverse effects on human health and environment. The present study based on the development and validation of a sensor network for high temporal resolution monitoring of total VOCs and BTEX concentration at selected sites nearby the industrial and port area of Taranto allowed to discriminate the contributions of the multiple emission sources, to identify short-emission events not otherwise detectable through the application of conventional methodological approaches and to raise the issue of the inhalation exposure of the population living in the surroundings.

It remains elusive about the effect of residential biomass burning (RBB) emissions on the particulate matters (PM) pollution and regional climate. The results oof WRF-Chem model simulations of persistent air pollution episodes show that the total contribution of RBB emissions to the near-surface PM_2.5 mass concentration during the simulation period is around 29.2% (18.4 μg m^-3) averaged over the GZB, with an average contribution of 52.6% to the SOA, suggesting that the RBB emissions should be considered in the air pollution control strategies for further alleviation of the wintertime PM pollution in the GZB under current conditions.

Atmospheric aerosols influence climate and air quality, but their molecular formation is not well understood. Computational methods can provide insights into molecular-level dynamics but are limited by system size. An alternative is machine learning interatomic potentials (MLIPs). We trained an MLIP using active learning on atmospheric organic molecules from the GECKO-A dataset. The model achieves good predictive performance for small to medium molecules but shows higher errors for larger accretion products. These errors can be addressed with further training and transfer learning. This MLIP offers an alternative to quantum chemistry, enabling studies of larger systems and advancing aerosol research.

We studied the spatiotemporal variation of particle number (PN) and black carbon (BC) concentrations in Helsinki, Finland, using annual datasets from 20 sites (2009-2024). In addition, the trends of PN, PN size distribution, BC and other pollutants were analyzed at a traffic supersite. The highest PN levels were at the airport terminal, highway and street canyon sites. At traffic sites, BC and NOx levels have decreased rapidly and PN more slowly. Annual mean BC concentrations are currently similar in busy traffic sites and detached housing areas with wood burning. Wood burning significantly impacts BC but has less impact on PN.

Urban air quality is a major challenge in rapidly developing cities such as Luanda, Angola, where traffic and industrial emissions contribute to high PM₁₀ levels, increasing cardiorespiratory risks. This study analysed PM₁₀ composition from June to November 2023, using thermo-optical analysis for carbon fractions, ICP-OES/MS for elements, and ion chromatography for water-soluble ions.PM₁₀ concentrations peaked on weekdays at 62.2 ± 15.5 µg/m³, with major oxides comprising 38%, elemental carbon 18%, and organic matter 27%, reflecting urban activities and climatic influences. The highest PM₁₀ levels occurred during the dry season, highlighting the impact of seasonal pollution dynamics.

This study assesses PM2.5 and CO₂ levels in classrooms across Spain, Portugal, Finland, and Romania, analyzing ventilation efficiency in primary, secondary, and university settings. Measurements from sensors in 20 classrooms show higher PM2.5 levels in Portugal (10.74 µg/m³) and Romania (10.11 µg/m³), while Finland had the lowest (2.23 µg/m³). CO₂ levels followed a similar trend, indicating poor ventilation contributes to particulate accumulation. Schools with mechanical ventilation had lower pollutant levels, underscoring its importance. Findings emphasize the need for improved ventilation strategies, particularly in naturally ventilated schools, to reduce exposure risks. This study is part of the ECF4CLIM project.

In Seoul, combustion-related components have been continuously observed. however, specific sources have not been clearly identified. In contrast, long-range transported PM2.5 exhibits a sharp increase during winter, accounts for a significant portion of PM2.5 mass, and primarily consists of secondary ionic components
In this study, the chemical composition of PM2.5 was analyzed, and emission sources were identified using the EPA PMF model. Organic marker compounds were utilized to distinguish PET & wood burning sources and tire wear. Additionally, long-range transported pollutants, including firework combustion, were comprehensively verified as non-regional sources.

Black carbon (BC) is an important primary species of particulate matter and a major contributor to air pollution. While BC proxy models have been successfully developed for urban environments, their application in rural areas remains poorly explored. In this study, machine learning models were developed to estimate BC concentrations in rural Slovenia. Using multiple linear regression, decision tree, random forest, and artificial neural networks, we predicted BC concentrations one hour in advance. The results show that the ANN model outperforms the other models, demonstrating its potential for estimating BC concentrations in areas with limited air quality measurements.

The main goal of the research was the determination of heavy metals concentration in aerosols in six size classes (7.2-10 𝜇m; 3.0-7.2 𝜇m; 1.5-3.0 𝜇m; 0.95-1.5 𝜇m; 0.49-0.95 𝜇m; <0.49 𝜇m) at 3 seaports (Bergen and Bodø, Norway and Malmo, Sweden) and at 12 stations between them. During the cruise from Gdynia (Poland) to Bodø (Norway) in the period from June 5 to July 2, 2024, in addition to aerosols, the microlayer and underwater samples were collected. It aimed to compare the degree of SML contamination in heavy metals in every single location under the influence of atmospheric dry deposition.

The Mont Blanc Tunnel (Italy–France) is undergoing an 18-year renovation plan with scheduled full closures for consecutive months each year. This presents a unique opportunity to investigate the impact of traffic emissions in surrounding Alpine areas. Nearly 180 PM10 samples were collected at both entrances (Courmayeur, Italy; Chamonix, France) between 2023 and 2024. Comprehensive chemical analyses (140 species/sample, including EC/OC, ions, metals, sugars, polyols, and organic acids) and oxidative potential assays were performed. Single-site PMFs identified key sources, but only a combined multi-site PMF approach ensured factor stability. Random forest meteorological normalisation enhanced traffic impact assessment.

It is well known that nanoparticles form during laser treatment of solid materials. However, as long as the treated material does not represent a health hazard on its own, the formed aerosol is usually not of worker’s concern and studies of produced particles are relatively scarce. We had a unique opportunity to support a high technology company during the development of laser ablation (LA) systems, investigating aerosols formed during the laser ablation of GaAs wafers and proposing appropiate safety measures accordingly. Particle concentration, size distribution, morphology and chemical composition were studied at the source and behind the filtration unit.

Meteorological conditions favoring PM10 accumulation occur mainly in winter, with high pressure, vertical stability, and weak circulation. Thermal inversions in valleys and lack of precipitation worsen pollution episodes. Strong day-night temperature variations also influence pollutant accumulation. The LaMMA Consortium applied a weather classification method to analyze the correlation between PM10 pollution and recurring meteorological patterns. Critical areas in Tuscany were identified using AirQino network data and WRF model outputs. Particulate matter compositional analyses revealed biomass burning from domestic heating as a major emission source, using techniques like ion chromatography, PIXE, and ICP-AES.

Aerosol light absorption can reduce near-surface PM2.5 during wintertime haze events. Absorbing aerosols create a “warm bubble” above the planetary boundary layer, generating secondary circulations that lower PM2.5. Additionally, aerosol absorption of UV light reduces photolysis, hindering ozone formation and suppressing secondary aerosols. Combined, these interactions decrease PM2.5 by 7.4%. This negative feedback should be considered in weather, climate, and health models.

This study aims to assess the performance of official methods in the challenging determination of Cr(VI) in Cr(III)-rich particulate matter and to develop a novel, robust analytical protocol to address this issue. This study involves the application of the developed method in the analysis of Cr(VI) in welding fumes, in occupational environments characterised by the processing of chromium-rich steels. The aim is to verify the reliability of the protocol in complex matrices, ensuring accuracy in chromium speciation and minimising false positives. A previous study was conducted in tannery environments.

Since 2007, ARPA Lombardia has monitored ammonia concentrations, a key precursor of ammonium nitrate, at urban and rural sites. Agriculture and slurry storage account for 96% of ammonia emissions in Lombardy, mainly from livestock farming and fertilizer use. Since 2017, intensive campaigns have analyzed ammonia emissions and particulate composition, studying different slurry spreading techniques. Data on PM₁₀, NH₃, NO_x, SO₂, and meteorological parameters were collected, along with particle size distribution. Measurements at farms and Milan’s urban site (Milano-Pascal) were compared to assess aerosol formation conditions. Findings from 2019-2025 will focus on aerosol size distribution and fertilization phases.

This study examines particulate matter (PM10) exposure at a school near an industrial estate in Portugal. Samples from classrooms and the schoolyard were analysed during winter and spring. Indoor PM10 concentrations averaged 24.0 µg/m³ in winter and 29.4 µg/m³ in spring, while outdoor levels were higher in winter (28.2 µg/m³). Major PM10 sources included fuel burning, sea salt, resuspended dust, and industrial activity. The study highlights the importance of identifying these sources to mitigate PM10 exposure, which can negatively impact children's health and academic performance.

The BIOINFO database is a unique information platform about biological threats in the work environment.

The database contains: information on applicable European laws, information necessary to assess occupational risk related to exposure to biological agents, checklists supporting occupational risk , description of qualitative and quantitative methods used in identification of air microbiological pollutants, characteristics of available measurement methods and the ways of interpreting their results, a list of major biological agents related to the professional activities in different work environments, and methods of protection and prevention against adverse effects of biological agents.

This study examines the deposition levels and chemical composition of the insoluble fraction and heavy metals in deposition particles (DP) from the Riotinto Mining District. To achieve this, three monitoring stations were selected, located in La Dehesa and the municipalities of Nerva and Minas de Riotinto, during the period 2022–2023.

Our objective is to conduct a sensitivity analysis between spatio-temporal models, based on different methods: Random Forest (RF) models, which have been widely used for exposure estimates in Italy, and statistical models based on the INLA-SPDE approach, in order to evaluate the potential for creating an integrated model (ensemble model).

We also aim to demonstrate the capability of both RF and INLA-SPDE methods to improve the surface concentration estimates produced by chemical diffusion and transport models as well as the spatial resolutions of these estimates, while maintaining sufficient temporal resolution for the main application purposes.

Dust storms affect air quality, climate, and health, making early warnings crucial. The Copernicus Atmosphere Monitoring Service (CAMS) provides PM10 estimates for forecasting, but existing discrepancies with ground measurements impact accuracy. AI-based models struggle due to scarce dust event data. This study proposes a machine-learning approach to correct CAMS PM10 fields using in-situ data. A gradient-boosting model predicts CAMS errors across the Eastern Mediterranean, improving accuracy by 12 μg m⁻³ on average. A deep neural network trained on bias-corrected PM10 fields enhances city-scale dust event forecasting (0–72 h) over the Balkans, improving AI-based predictions across all metrics.

This study aims to evaluate the impact of tire wear on airborne PM emissions through real-world on-road driving experiments using actual vehicles. When sampling particles under real driving conditions, particles from various sources are mixed. To selectively analyze tire-road wear particles (TRWPs), pyrolysis gas chromatography-mass spectrometry (GC–MS) was employed, as described in ISO/TS 20593. A tracer gas experiment was conducted to correlate TRWP concentrations obtained using the pyrolysis GC-MS method with an emission factor. The results revealed that 3.1% of tire wear particles fall within the PM10 fraction, of which 14% belong to the PM2.5 fraction.

This study evaluates electrostatic precipitator (ESP) aerosol collection efficiency under different jet flow velocity profiles using a 2D axisymmetric model in COMSOL Multiphysics 6.3. Simulating laminar flow at 0.3 L/min with a 25 kV potential, it compares uniform and fully-developed inlet flows. Results indicate uniform flow enhances collection efficiency. Since real-world inlet pathways are often too short for fully developed flow, the study emphasizes the need to consider velocity variations when assessing ESP performance. These findings align with prior research and commercial applications of ESPs for aerosol sampling.

This study aims to investigate the time profiles of pollutants concentrations in a church and basilica during the liturgical celebrations in order to estimate the emissions dynamic induced by incense burning and its potential health impacts, so were carried out two high-time and spatial resolved monitoring campaigns. The preliminary results showed that during the hours of greatest crowd of faithful and in correspondence of incense use significant concentrations increment of all investigated pollutants were registered. Therefore, this study allowed to highlight the significant impact of the incense burning on IAQ and, thus, health of priests and altar boys.

Indoor air pollution poses a serious risk to public health. People can encounter different pollutants in places like homes, workplaces, vehicles, and recreational areas. There is a uneed to understand how different sources and activities contribute to air pollution over time in these spaces. The InAPI tool is built on a database of indoor air pollutants in the UK. It organizes information about pollutants, environments, and occupants' activities, and provides data on indoor pollutant concentrations and their emission rates. This is vital for researchers and policymakers to inform interventions as well as guide future research in managing indoor air quality.

While knowledge about the physico-chemical and biological properties of bioaerosols from various man-made and natural environments is increasing, significant gaps still exist that hinder our understanding of the role and impact of bioaerosols on public health, climate, and ecosystems. This project seeks to harness the advancements in sensing and molecular analysis technologies and data analytics for the real-time detection and characterization of bioaerosols in varied environments, enhancing our understanding of their nature, magnitude, fate, behaviour, and the resultant impact pathways.