Spatial variability and source apportionment of particulate matter (PM2.5) in Rio de Janeiro: insights from Urban, preserved, and biomass burning areas

Abstract Air pollution is a critical environmental issue influenced by both natural and anthropogenic sources. We hypothesized that PM 2.5 chemical composition varies spatially due to local anthropogenic sources, soil resuspension, and biomass burning. This study analyzed particulate matter (PM 2.5 ) concentrations and chemical composition (black carbon (BC), elements, and ions) in three locations in Rio de Janeiro state: Gávea (urban area), PARNASO (environmental preservation area), and Campos dos Goytacazes (urban with burning biomass). The results show that PM 2.5 concentrations varied significantly among the sampled sites, with the average highest values recorded in PARNASO (20 ± 13 µg m − 3 ), followed by Gávea (12 ± 7 µg m − 3 ), and Campos (8 ± 4 µg m − 3 ). Although no daily samples exceeded Brazilian air quality standards, 23% surpassed WHO guidelines. Fe and Al were the most abundant elements in all sites, indicating strong soil resuspension influence, with higher concentrations in Campos. BC was higher in PARNASO (2.2 ± 0.9 µg m − 3 ) but contributed more to PM 2.5 in Campos (22–24%), highlighting the biomass-burning influence. Water-soluble ions, particularly Cl − , Na + , SO 4 2− , and NO 3 − , were predominant across all sites, with K + showing statistical differences between seasonality in Campos. A Principal Component Analysis (PCA) identified soil resuspension, vehicular emissions, and biomass burning as major contributors to PM 2.5 pollution. These findings underscore the necessity for region-specific air quality policies and continuous monitoring, emphasizing their global relevance for effective long-term pollution mitigation in urban, and preserved areas.