Biomass burning (BB) emits pollutants affecting air quality, climate, and health, but its aerosol composition and transformation remain unclear. This work presents the set-up and rationale of a campaign conducted at the high-volume EUPHORE simulation chamber. An in-depth characterization of gas and particle-phase emissions and optical properties from domestic stoves burning oak, pine, and pellet-wood in flaming and smoldering phases and oxidized under day and nighttime conditions was done along with human cell exposure to asses toxicological risks. Focusing on aerosol composition characterization (API-ToF-CIMS+FIGAERO), this work aims to improve understanding of BB emissions, supporting air quality models and mitigation strategies.

Polycyclic aromatic hydrocarbons (PAHs) and oxygenated derivatives (OPAHs) were measured in the particle phase of pellet and wood stove burning emissions through a series of experiments. PAHs and OPAHs wood-burning emissions were characterized under fresh, daytime-aged (oxidation by OH radicals) and nighttime-aged (oxidation by NO₃ radicals) experimental conditions in the chamber. Besides the effects of aging, the PAC levels were studied under different relative humidity (RH) conditions. Furthermore, the toxicity indicator, Benzo(a)pyrene equivalent (BaPeq), was calculated for the different experiments. Finally, the chamber PAC profile was compared to the biomass burning source profile (from PMF analysis) for ambient particle PACs.

Black carbon (BC) is a key anthropogenic climate forcer, with its radiative impact depending on its absorption, cloud activation, and ice-nucleating properties. These evolve with atmospheric ageing, which is challenging to parameterize in models, leading to uncertainties in Arctic BC forcing estimates. The ARCTEx project investigated BC ageing timescales under Arctic transport conditions using the AIDA chamber. Results show altitude strongly modulates BC ageing, with rapid transformation at low altitudes but stable fractal-like BC at high altitudes. Seasonal effects influenced optical and cloud activation properties. Findings highlight the need to refine BC ageing in climate models.

In our study, we found that the oxidation of naphthalene by OH radicals, combined with the presence of ozone, significantly increases the formation of highly oxygenated organic molecules (HOM) contributing to secondary organic aerosol (SOA) formation. Experiments showed that ozone plays a crucial role in the rapid oxidation of polyaromatic hydrocarbons (PAHs) like naphthalene, 1 and 2-naphthols, biphenyl and anthracene affecting SOA formation. These insights help resolve discrepancies in previous molecular-level studies.

Recent advances in computational chemistry and physics have enabled fully ab initio cluster formation simulations, crucial for understanding aerosol nucleation. However, challenges remain in combining quantum-level theory with molecular dynamics (MD) simulations. A key issue is the classical treatment of atomic motion in MD, which can misrepresent energy distribution, artificially accelerating processes like evaporation. Additionally, thermostatting algorithms, while maintaining temperature, may introduce unphysical effects. These concerns are particularly relevant in atmospheric nucleation studies, where best practices are still evolving. Addressing these methodological challenges will improve simulation accuracy, ensuring better representation of real-world processes and advancing aerosol science.

The diffusivity of aerosol nanoparticles (NPs) under 5 nm is crucial for nanotechnology and aerosol science yet remains unclear. Experiments used micron-sized particles at low pressures to achieve high Knudsen numbers, overlooking the critical atomic-level interactions. Here, molecular dynamics simulations provide diffusivities of fullerene and silica NPs (0.4 to 7 nm) in air, accounting for detailed structure and force fields. Below 3 nm, NP-diffusivities align well with gas diffusivity correlations but deviate from classic equations like Epstein and Stokes-Cunningham-Millikan for particle diffusivity. Differences become more pronounced as NPs approach gas-molecule sizes, while above 5 nm, NP-diffusivities converge with classic equations.

Aerosol Spray Pyrolysis (ASP) is an efficient method for synthesizing iron-based nanoparticles, which are widely used in biomedicine and catalysis. The characteristics of resulting nanoparticles, including size and structure, depend on precursor composition and processing conditions. This study uses molecular dynamics (MD) simulations to investigate nanodroplet evaporation process that leads to nanoparticle formation. Results show iron ions precipitate on the droplet surface, forming a core-shell structure, with Fe³⁺ from iron nitrate favoring this formation more than iron chloride. The MD model results aligns well with experiments and provides insights into key parameters like diffusivity and evaporation, which are difficult to measure experimentally.

This presentation highlights the role of external charging in flame synthesis and its impact on the evolution of nanoparticles generated in the system. The study focused on MgO nanoparticles formed during magnesium combustion. Negative ion emission resulted in partial melting of nanoparticles, while positive ions had little effect. Numerical estimates showed that the observed effect was possible due to the influence of external charging on the thermionic emission of electrons from growing nanoparticles, which could play a significant role in the overall heat exchange. This emphasizes the need to consider the corresponding gas-nanoparticle heat transfer channel in accurate modeling.

Coral reefs are among the most diverse ecosystems in the world and widely considered a potential source of aerosol particles. In this study, we present for the first time direct observations of coral reefs contribution to aerosol number size distributions above the Great Barrier Reef in Queensland, Australia. Our results show that air masses that spend more time directly over the coral reef exhibit higher fraction of the total particle number concentration in the Aitken mode and smaller diameter sizes than air masses that pass over the open ocean instead.

Atmospheric pollution affects the reliability of electric power systems by contaminating insulators with aerosol deposits, increasing surface conductivity and the risk of flashover events. This study examines the chemical composition and phase transitions of these deposits using ISORROPIA II, a thermodynamic model. Unlike standard atmospheric aerosols, insulator deposits are ammonium-poor and rich in crustal species, leading to model discrepancies. Experimental validation in an Aerosol Exposure Chamber identified necessary coding refinements, improving ISORROPIA’s predictive accuracy. This research enhances predictive models for power grid maintenance, contributing to a more reliable Italian electric system by mitigating contamination-related risks.

During the ACROSS campaign in suburban Paris (Summer 2022), hygroscopic growth and chemical composition of aerosols were analyzed using HTDMA and HR-ToF-AMS. Distinct growth factor modes—hydrophobic and hygroscopic—were identified, with hygroscopicity increasing with particle size. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule revealed poor predictability for hygroscopic growth, particularly in externally mixed particles, influencing hygroscopicity predictions significantly. A cluster analysis of air mass backward trajectories provided insights into variations in chemical composition and hygroscopicity. Our study (Deshmukh et al., 2025) highlights the complex interplay between aerosol properties, chemical composition, and atmospheric processes, providing valuable insights for future research in this field.

Exposure to particulate matter (PM) in indoor environments has been associated with adverse health effects. To assess the relative importance of outdoor pollution and internal sources on the sub-micrometer PM indoor levels and properties, a series of indoor characterization experiments was conducted in different environments. The resulting data show that outdoor aerosols can undergo significant modifications once transported indoors because of losses of certain components and/or size fractions or addition of indoor-specific components. This can affect the particles toxicological properties in ways that are still not quantitatively understood.

A hierarchical clustering approach was employed to identify the macro-source of organic compounds detected in a year-long dataset of PM2.5 samples collected from two sites using a UHPLC-HESI-HRMS system. The comparison between the agricultural and urban sites revealed that organic aerosols could affect human health differently, even when the measured organic carbon concentrations are extremely similar.

The chemical composition of the atmosphere is changing rapidly due to increasing anthropogenic activities. Especially the upper troposphere and lower stratosphere (UTLS) are sensitive to changes in chemical composition. Here, we present two case studies from the TPEx aircraft campaign in Germany in June 2024, probing different regions of the UTLS. An analysis of the collected filter samples by high-resolution orbitrap mass spectrometry and a subsequent non-target analysis allows for the identification of yet unknown compounds. Our findings reveal unique stratospheric compounds such as organoposphates, suspecting anthropogenic influence in the upper atmospheric layers.

Ultrafine particles (UFP) are of great health concern due to their small size, high surface area and potential to deeply penetrate into the lung. Sampling and analysis of UFP are challenged due to their low mass. Herein, we present results from a field campaign in which UFP were collected for 24 h on quartz fiber filters and subsequently analyzed using sophisticated analytical techniques. We found high seasonal but also daily variations for the quantified PAHs as well as the classified compound classes including hopanes. Correlations to physico-chemical and weather data were approached and the potential impact of local sources evaluated.

This study investigates the formation of SOA from the oxidation of two monoterpenes, limonene and sabinene, in an atmospheric chamber. The research aims to expand knowledge of aerosol formation, particularly the chemical structure and prominence of molecular dimers in monoterpene oxidation. Non-targeted analysis revealed oxidation products varying with temperature caused by differences in physical properties. Dimer masses were detected for sabinene and structural identification was attempted, with a dimer of MW 338 showing similarities to an equivalent beta-pinene dimer. In future, dimer investigations will be performed on aerosol samples from Hyytiala, Finland, in particular, searching for cross-product dimers.

In tropical forests, organic aerosols dominate atmospheric particles, with both, secondary (SOA) and primary organic aerosols (POA) playing key roles. However, distinguishing molecular markers for SOA and POA remains challenging. The Amazon basin provides a unique environment to study these interactions under pristine and polluted conditions. This study presents a size-resolved molecular characterization of OA using high-resolution mass spectrometry. Aerosol samples were collected at the Amazon Tall Tower Observatory, analyzed for molecular markers, and evaluated for source contributions. The results reveal multimodal distributions, highlighting the need for further research to understand the roles of POA and SOA in aerosol formation.

Surfactants characterization is essential to understand their role on cloud formation and aerosol surface properties. A new analytical procedure was developed and applied to aerosol and cloud samples from different environments to quantify surfactants and measure their surface tension properties. The results highlight the ubiquity and high concentrations of surfactants in the atmosphere, especially anionic surfactants. The surface tension of aerosol and the partitioning of surfactants between the surface and bulk phases in particles were calculated using three models derived from the literature, and applied to the surface tension results. The potential implications for cloud formation will be discussed.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Prescribed burns reduce wildfire risks but expose firefighters to hazardous pollutants like PAHs and black carbon (BC). This study analyzed BC and PAH exposure in 35 samples from Catalonia (2022–2024), finding that torchers faced the highest exposure (mean BC: 69 µg/m³, PAHs: 394 ng/m³), while truck drivers had the lowest. BC correlated strongly with PAHs, suggesting its use as a monitoring proxy. Torch operators' cancer risk exceeded safety thresholds by 3.5–4.3 times. Findings highlight the need for improved respiratory protection and safety measures to reduce health risks for firefighters in fire-prone regions.

Polycyclic aromatic compounds (PACs: PAHs and their oxygenated and nitrated derivatives – OPAHs and NPAHs), organic molecules originating from incomplete combustion activities with severe impact on human health, were used in source apportionment study in a Greek urban center severely impacted by residential BB.The combination of PAC source assessment using receptor modeling with carcinogenic exposure assessment using an expanded dataset of toxicity-equivalent factors (TEFs) permits source-specific carcinogenic risk assessment (BaPeq).The major PAC source was Biomass burning (>80%), proving that mitigation strategies for residential BB activities could significantly improve the city’s air quality and help attain the EU BaP standard.

This study presents results of ambient air quality measurements in a residential area using a diffusion-charge based UFP-monitor (Palas) and a Black-Carbon measurement device (Aethlabs) during the winter months (December 2024 – February 2025). The measurement devices were installed at an individual home and have a high temporal resolution (1 minute) to reflect short-term (peak) exposures and the local concentration dynamics. Wood-stove exhaust as a consequence of domestic heating is a significant contributor to air pollution in residential areas. Maximum daily 1-hour-mean concentrations exceed 20 000 #/cm³ (WHO good-practice statement) on approx. 31 % of days of the measurement period.

Floor mopping experiments were performed in a stainless steel environmental chamber. The chamber had a volume of 7.6 m³ and was equipped with an active carbon and a HEPA filter. The particle number size distribution was measured with a Partector2 (Naneos) in the size range between 10 - 300 nm, and with an OPS (TSI) in the size range between 0.3 - 10 μm. The PM_2.5 mass concentration was measured with a Dust Trak II (TSI) whilst VOC measurements were performed with a Phocheck Tiger (Ion Science). Indoor temperature, relative humidity and CO₂ were recorder with an IAQ Calc (TSI).

This study examines the effects of aerosol deposition on Pusa Sadabahar tomato plants under controlled conditions. Plants without stress exhibited superior morphology, while relative water content (RWC) declined by 12.31% under PM exposure, alongside reductions in leaf pH, ascorbic acid, and chlorophyll content, impairing photosynthesis. SEM analysis revealed stomatal blockage, disrupting conductance and water use efficiency. PM deposition ranged from 70 µg/cm² in HEPA-filtered chambers to 570 µg/cm² in elevated PM chambers. Interestingly, the ambient aerosol chamber yielded 25% more fruit, suggesting a PM threshold where nutrient adsorption benefits growth, while excessive PM caused stress, impacting productivity.

This study investigates the air-purifying potential of Myrtus communis, Nerium oleander, and Taxus baccata using the ChAMBRe atmospheric simulation chamber. Plants were exposed to NO₂, SOOT, DUST, and a MIX condition, with pollutant capture analyzed via scanning electron microscopy. M. communis was most effective at SOOT removal, while T. baccata and N. oleander excelled at capturing DUST. These differences persisted in mixed conditions, highlighting species-specific pollutant affinities. The findings provide valuable insights into plant-pollutant interactions, supporting urban greening strategies to improve air quality, particularly in port cities affected by high pollution levels.

Under certain conditions in the atmosphere, pollen grains, that are otherwise too large to enter the lower respiratory tract, can fragment into smaller particles that are called subpollen particles (SPPs). SPPs are frequently in the respirable size range. Specifically, during thunderstorms, SPPs can be released at very high amounts, and trigger more severe allergic reactions, intensifying conditions like Thunderstorm Asthma (TA). This study investigates the role of electrical charges in pollen rupturing during stormy conditions by simulating pollen-charge interactions for wind-pollinated pollen grains from the Lolium (Perennial Ryegrass) family.

The study focuses on the characterization of the airborne bacterial and fungal communities sampled across 28 urban, rural, and coastal sites from five Central Mediterranean regions (South Italy, Albania, Malta, and Zakynthos) in February 2024. Applying DNA metabarcoding and compositional data analysis, several genera, mostly including potentially human and plant pathogenic species, were identified. Regarding bacterial communities, Sphingomonas was detected in every location, while Brevundimonas, Geodermatophilus, and Rubrobacter dominated rural and coastal areas. Within fungal communities, Cladosporium and Alternaria were also prevalent in rural and coastal sites. Overall, the findings reveal complex microbial-environment interactions, highlighting potential health and agricultural impacts.

Sea salt aerosols, a major aerosol type in the atmosphere, can take up water at Relative Humidities (RHs) well below deliquescence. This surface water can create chemically active environments that may catalyze reactions. However our understanding of these phenomena is still limited. In this study, we investigated phenomena on sea salt surfaces exposed to different RHs, at the nanometer scale, using Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS). At the lowest RH (7%), we observed spontaneous surface chemistry leading to the formation of oxidized chlorine species, likely chlorate (ClO3-). This study reveals a new pathway for chlorate formation in the atmosphere.

Oligomerization of organic compounds produces non-volatile dimers, but their formation mechanism remains unclear. Dimerization affects monomer vapor pressure and enhances FNP stability by suppressing evaporation. Once formed, dimers are unlikely to re-evaporate from FNPs.

Quantifying inhalable particles generated by explosions is a key factor in defining the target to be protected from such an event in the context of radioactive material. This study focuses on the particles generated by explosions in contact of concrete radioactive waste packages. The main objective is to quantify the mass of particles smaller than 10 μm in terms of aerodynamic diameter. For that purpose, we developed a protocol and measured a reasonable envelope of the mass of particles collected after concrete specimen explosions, at middle-scale.

This study focuses on detecting Saharan dust events (SDE) using in-situ aerosol optical properties and radiative forcing efficiency (RFE) at the high-altitude Helmos Hellenic Atmospheric Aerosol and Climate Change (HAC²) station in Greece. Intensive optical properties, including single scattering albedo (SSA), scattering Ångström exponent (SAE), absorption Ångström exponent (AAE), and single scattering albedo Ångström exponent (SSAAE), were assessed alongside the aerosol coarse-to-total volume concentration ratio (CV/TV). Metrics were validated using dust forecasts and air mass trajectories. During SDE, SAE and SSAAE decreased significantly, while CV/TV increased (>0.7), highlighting strong aerosol impacts on regional climate through more negative RFE.

The southeastern U.S. is home to high warm-season concentrations of sulfates and biogenic secondary organic aerosol (SOA). Changing aerosol loading and chemical speciation in the region has implications for regional air quality, radiative transfer, aqueous phase SOA production, and aerosol-cloud interactions. This presentation focuses on the relationships between aerosol optical properties, cloud condensation nuclei, aerosol size distributions and chemical speciation, measured at the NOAA and NASA federated aerosol network sites at Appalachian State University. These relationships can help elucidate how the changing aerosol composition is likely to impact regional CCN concentrations and CCN spectra, biogenic SOA production, and radiative transfer.

The BIO-MASTER project investigates the relationships between bioaerosol composition and the optical/physical properties of atmospheric aerosols in a Central Mediterranean area. Two intensive monitoring campaigns were conducted at the University of Salento, Lecce, between December 2023 and October 2024, using innovative sampling and analysis techniques. These included the WIBS-NEO sensor for fluorescence-based bioaerosol detection and the ACD-200 Bobcat sampler for particulate matter. The study employed metagenomic analysis to identify bacterial and fungal communities in the aerosol samples, revealing seasonal variation in bioaerosol composition and emphasizing the need for standardized sampling protocols.

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.

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.

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.

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.

Free and combined amino acids and nucleobases were measured in extracts from Antarctic marine aerosol and water samples. Transfer processes were studied, revealing a gap for atmospheric biotic and abiotic processing of the analytes. Samples were also investigated for mass, back trajectories, Ion concentrations and OC/EC or WSOC.

The SIDDARTA project aims to investigate present-day sources and transport processes supplying mineral dust to the Antarctic plateau. The project includes the study of the composition of mineral dust at Dome C (Concordia Station), both in the form of atmospheric particulate matter (PM₁₀), surface snow and snow-pit samples (to achieve a multi-annual record of dust deposition), as well as the resuspension and analysis of soil samples previously collected in Potential Source Areas (PSA) in Australia and Southern South America. The analysis included measurements of elemental composition, major and trace metals, and isotopic composition of Pb and Sr.

Antarctica, the coldest and driest continent, is crucial for global climate regulation. Recent warming trends, especially in West Antarctica and the Antarctic Peninsula, have increased surface melting and altered precipitation patterns. Atmospheric Rivers (ARs), though infrequent, contribute significantly to precipitation, ice shelf destabilization, and microbial transport. To study microbial communities in precipitation over the northern Antarctic Peninsula, we conducted a culture-dependent analysis on samples from expeditons during 2022 and 2024. Using DNA sequencing and back-trajectory analysis, we identified viable microbial taxa and their sources. These findings provide insights into the role of ARs in microbial dispersal and ecosystem impacts.

Clouds enhance Antarctic Ice Sheet melting through thermal-infrared emissions but remain poorly understood and misrepresented in models. Inaccurate treatment of ice-nucleating particles and cloud condensation nuclei impacts cloud persistence and radiative effects. Surface aerosol observations represent local features, while satellite sensing struggles with low concentrations. To address this, two campaigns in 2024-2025 deployed a tethered balloon for vertical profiles at Neumayer III Station and a Twin Otter aircraft for a 15000 km transect. These platforms measured aerosols concentrations, providing insights into regional variability, with the aim of improving the representation of aerosol-cloud interactions in the Antarctic lower troposphere.

The Southern Ocean and Antarctica are remote from anthropogenic influence, making the region one of the most pristine in the world and a unique testbed for probing natural atmospheric processes. Understanding these “baseline” conditions is critical for reducing the uncertainty in our climate models. A recent effort, PICCAASO, was initiated to coordinate the over 20 international projects funded since 2020 aimed at investigating the complex natural interactions between ocean biogeochemistry, trace gas emissions, aerosols and clouds. In this presentation, early results from several Australian-based PICCAASO-themed campaigns (MISO, CAPE-k, COAST-k and Denman Marine Voyage) in the region are presented.

Approximately 2% of the managed forest in Sweden is harvested annually. Our research captured a clearcutting event in 2022 at the Norunda station in Swedish boreal forest. During clearcutting, an increase in monoterpene concentration to over 60 ppb was observed. Sesquiterpene and diterpene showed diurnal patterns similar to that of monoterpene in pre-, during, and post-cutting periods. Isoprene did not show a significant increase. The cutting event altered the ratios of different BVOC, which further influenced the SOA formation. Higher signals of particulate organic compounds were observed during cutting. BVOC showed varying contributions to SOA compositions across different periods.

The Po Valley in Italy is a hotspot of pollution in Europe. In winter radiation fog occurs and affects the air composition, where gas-phase changes of organic aerosol are understudied. During in-situ observations in winter/spring 2021/2022 we analyzed the molecular-level chemical composition changes of organic aerosol in the gas and particle phase in the presence of fog, using mass spectrometry. Preliminary results show changes in the volatility distributions for both phases, suggesting scavenging by the droplets and phase partitioning. The study helps to establish a better assessment of aerosol-fog interactions on human health and climate in polluted regions.

This study investigates secondary organic aerosol (SOA) formation in São Paulo, a megacity influenced by both biogenic and anthropogenic emissions. Field measurements during the BIOMASP⁺ campaign (April-May 2023) were combined with chamber experiments to study VOC oxidation and SOA composition. Using CHARON-PTR-ToF-MS, the average SOA concentration was 4.5 µg m⁻³, with C_xH_yO₂, C_xH_yO₃, and C_xH_yO₄ compounds contributing most. High-NO_x isoprene markers, linked to polluted conditions, dominated, while low-NO_x epoxydiol products were scarce. This research enhances understanding of SOA formation mechanisms in biogenically influenced urban areas, supporting improved air quality management in complex urban environments like São Paulo.

The study investigates the seasonal transition of organic gases and particles in a polluted megcity, focusing on secondary organic aerosol (SOA) formation at molecular level. Using advanced mass spectrometry techniques, the research captures shifts from winter heating emissions to biogenic sources in spring. It highlights how volatile organic compounds (VOCs) and SOA compositions change with pollution levels and seasonal influences. Key findings include the transition from biomass burning SOA (BBOA) to biogenic SOA (BSOA) and the distinct role of fresh emissions. The study underscores the importance of co-located gas and particle-phase measurements in understanding complex atmospheric processes.

Biomass burning is a major source of PM₂.₅, significantly impacting air quality and SOA formation. This study investigates the molecular evolution of biomass burning OA (BBOA) through a field campaign in Punjab, integrating EESI-TOF and Orbitrap MS for high-resolution analysis. Fresh BBOA showed higher CHN compounds, while aged samples were enriched in unsaturated CHO species. Clustering analysis identified key molecular tracers increasing with aging. These findings support a molecular-tracer-based SOA estimation framework, enhancing assessments of smoke plume impacts on urban air pollution in South Asia.