This study uses advanced computer simulations to explore how falling water drops remove airborne particles. It shows that, when drops deform and oscillate, their motion strongly affects how efficiently aerosols are captured. The model accurately predicts drop speed and shape, but capture rates can differ from experiments by up to an order of magnitude. These gaps likely stem from missing physical effects (evaporation), uncertainties in aerosol measurements, and numerical inaccuracies.

The Marseille–Fos basin faces high anthropogenic pressure from industry and maritime and road transport combined with specific weather conditions that further degrade air quality. Our study focuses on fine metallic pollution, which can penetrate deep into the lungs and cause harmful effects. Using 1 year of measurements at two sites, we identified 10 main pollution sources, half directly linked to human activities, highlighting clear risks for the environment and public health.

This study examines NH₃ emissions from UK agriculture and the role it plays in PM_2.5 formation, focusing on the dairy, pig, and poultry sectors. Using regional and local air quality models, we find that a 13 % NH₃ reduction cuts PM_2.5 by only ~1 % due to NH₃-rich air. The regional model may underestimate PM_2.5, while the local modelling shows that emissions disperse within 700 m. The study highlights the value of combining models to better understand the spread of pollutants and to improve PM_2.5 control strategies.

Coastal aerosols in Scandinavian urban areas remain understudied. We examined aerosol optical properties and size distributions along Denmark's coastline. Combining in situ data with dispersion modelling, we identified two main aerosol types: carbonaceous aerosols from fossil fuel and biomass burning and large, highly scattering aerosols (potentially sea salt). Black carbon from in situ data and dispersion modelling correlated well, while FLEXPART underestimated the concentration.

Seven years of hourly particle number size distributions of 10–500 nanometres were measured at an urban background in Germany. A downward trend of total particle number concentrations of −2 % per year was observed. Wind from the Frankfurt Airport showed the highest nucleation mode particle concentrations. Lockdown lowered the concentration of ultrafine particles in the direction of the airport. On 30 % of all days, the World Health Organization's ultrafine particles value for high concentrations was exceeded.

Small airborne particles influence how clouds form and how they affect the climate. Our study compared eight different instruments that measure the size distributions of these particles to understand the instruments' strengths and weaknesses. We found that some systems are more accurate, whereas others are more sensitive at tiny sizes. These results will help to improve future monitoring of air quality and climate processes.