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.