Source apportionment and ecotoxicity of PM 2.5 pollution events in a major Southern Hemisphere megacity: influence of a biofuel-impacted fleet and biomass burning

作者：Guilherme Martins Pereira, Leonardo Yoshiaki Kamigauti, Rubens Fabio Pereira, Djacinto Monteiro dos Santos, Thayná da Silva Santos, José Vinícius Martins, Célia Alves, Cátia Gonçalves, Ismael Casotti Rienda, Nóra Kováts, Thiago Nogueira, Luciana V. Rizzo, Paulo Artaxo, Regina Maura de Miranda, Márcia Akemi Yamasoe, Edmílson Dias de Freitas, Pérola de Castro Vasconcellos, María de Fátima Andrade · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-4587-2025 · 被引用次数：12 · 研究领域：Atmospheric chemistry and aerosols、Air Quality and Health Impacts、Vehicle emissions and performance

Abstract. The Metropolitan Area of São Paulo (MASP) in Brazil has reduced its vehicular emissions in the last decades. However, it is still affected by air pollution events, mainly in the winter, characterized as a dry season. The chemical composition of fine particulate matter (PM2.5) was studied in the MASP during a 100 d dry period in 2019. PM2.5 samples underwent an extensive chemical characterization (including inorganic and organic species), ecotoxicity was assessed using a bioluminescence-based assay, and submicrometer particle number size distributions were simultaneously monitored. PM2.5 concentrations exceeded the new World Health Organization's daily guidelines on 75 % of sampling days, emphasizing the need for strengthening local regulations. Source apportionment (positive matrix factorization, PMF5.0) was performed, and the sources related to vehicular emissions remain relevant (over 40 % of PM2.5). A high contribution of biomass burning was observed, reaching 25 % of PM2.5 mass and correlated with sample ecotoxicity. This input was associated with north and northwest winds, suggesting other emerging sources besides sugarcane burning (forest fires and sugarcane bagasse power plants). A mixed factor of vehicular emissions and road dust resuspension increased throughout the campaign was related to stronger winds, suggesting a significant resuspension. The sulfate secondary formation was related to humid conditions. Additionally, monitoring size particle distributio...