OA is a major component of particulate matter (PM) that affects air quality and health, especially in highly polluted, low-income, densly populated cities. This study examines organic aerosol (OA) in São Paulo, Brazil, using water-based offline setup with soft and hard ionization mass spectrometry. This study provides a detailed chemical characterization and quantitative analysis using AMS-LToF and EESI-ToF, along with source apportionment of the primary and secondary OA drivers in Sao Paulo, Brazil’s most populous city.

Identifying aerosol sources is key to air quality policies. Traditional methods rely on chemical analysis but are labor-intensive and limit data coverage. This study proposes a novel approach using physical properties (size distribution and light absorption) from high-time-resolution optical instruments: a particle counter (Palas Fidas 200) and an aethalometer (AE33). PMF of hourly data identifies six PM10 sources, validated against traditional methods and active/passive remote sensing. Applications of real-time implementation include wildfire smoke and pollution transport tracking, and emergency surveillance. This cost-effective technique enhances spatial and temporal resolution, supporting the new EU Air Quality directive by improving emission pattern analysis.

Multi-year observations at three Irish coastal sites—Mace Head, Valentia, and Carnsore Point—reveal dynamic interactions between marine and continental aerosols in the northeastern Atlantic. Using an HR-ToF-AMS, ACSMs, and gas analysers, we monitored organic aerosols (OAs), black carbon, and trace gases for a decade. Positive matrix factorization identified primary and secondary OA sources, including marine biogenic emissions, peat burning, and continental pollution. Long-range transport events were studied with backtrajectories, while decadal trends were analysed with advanced statistics to assess impacts of climate change, anthropogenic pollution, and air quality regulation. This study lays the groundwork for integrating observations with climate models effectively.

Ultrafine particles, defined as aerosols with diameter smaller than 100 nm, represent a growing concern due to their significant impact on human health and the environment. Despite their importance, our knowledge of UFP size distribution and the processes determining their atmospheric dynamics and air-surface fluxes remains limited.

To address these gaps, a comprehensive experimental campaign was conducted from October 2024 to March 2025 at the “Comando Generale dei Carabinieri” in downtown Rome adjacent to Villa Ada, a large urban park. This location offers a unique opportunity to explore the interactions between urban emissions and vegetation in a composed environment.

Aerosol particles in the atmosphere over the Qinghai-Tibet Plateau (QTP) are important but less understood due to paucity of measurements. We presented the key findings from an intensive field observation of atmospheric aerosols in the central QTP region in summer 2022 mainly using SP-AMS, SMPS, and AE33. During the measurement period, coincided with the monsoon season, the average mass concentration of submicron aerosol was 0.98 ± 0.60 μg/m³, dominated by organic aerosol (OA). Five sources or processes were identified for OA using Positive Matrix Factorization (PMF). Two special events were selected as the “high-sulfate” and the “high-nitrate” periods and discussed.