Spatiotemporal Analysis and Physicochemical Profiling of PM10 and PM2.5 in Slovenia

Particulate matter (PM10 and PM2.5) is a key contributor to urban air pollution and poses significant health risks, particularly in densely populated areas. While conventional air quality monitoring focuses on particle size and concentration, this study emphasizes the importance of understanding chemical composition and emission sources for effective air pollution management. PM samples were collected between 2019 and 2022 at two locations in the Republic of Slovenia: a traffic-dominated urban site and an industrial area. Annual average PM10 concentrations ranged from 14 to 34 µg/m3, and those of PM2.5 ranged from 9 to 22 µg/m3. In addition to decreasing annual concentrations, a notable reduction in exceedance days was observed between 2019 and 2022, indicating the effectiveness of recent air quality improvement measures. Meteorological data and statistical models were used to assess environmental influences on PM variability. Advanced SEM-EDS analysis revealed substantial seasonal and spatial differences in particle composition, with key elements such as silicon (4.3–28.4%), carbon (13.1–61.7%), and trace amounts of lead and zinc varying across sites and particle types. Mineral dust (Si, Al, Ca, Fe, Mg), originating from soil resuspension, construction, and Saharan dust, was dominant. Combustion-related particles containing C, Pb, Zn, and Fe oxides were associated with vehicle emissions, industrial processes, and biomass burning. Secondary aerosols, such as sulphates and nitrates, showed seasonal trends, with higher concentrations in summer and winter, respectively. The results confirm that PM levels are driven by complex interactions between local emissions, weather conditions, and seasonal dynamics. The study supports targeted policy measures, particularly regarding residential heating and traffic emissions, to improve air quality.