摘要：AbstractHaving a better understanding of air pollutants in railway systems is crucial to ensure a clean public transport. This study measured, for the first time in Brazil, nanoparticles (NPs) and black carbon (BC) on two ground-level platforms and inside trains of the Metropolitan Area of Porto Alegre (MAPA). An intense sampling campaign during thirteen consecutive months was carried out and the chemical composition of NPs was examined by advanced microscopy techniques. The results showed that highest concentrations of the pollutants occur in colder seasons and influenced by variables such as frequency of the trains and passenger densities. Also, internal and external sources of pollution at the stations were identified. The predominance of NPs enriched with metals that increase oxidative stress like Cd, Fe, Pb, Cr, Zn, Ni, V, Hg, Sn, and Ba both on the platforms and inside trains, including Fe-minerals as hematite and magnetite, represents a critical risk to the health of passengers and employees of the system. This interdisciplinary and multi-analytical study aims to provide an improved understanding of reported adverse health effects induced by railway system aerosols.Graphical abstractDisplay OmittedHighlights•Reducing NPs and BC levels at railway stations is crucial to ensure clean transport•Metal-enriched composition indicates a high toxicity of NPs.•NPs on railway stations are influenced by emissions from external sources.•The use of air-conditioning with no maintenance is a factor of indoor air pollution.•Hematite, magnetite and jarosite were found both on the platforms and inside trains.
关键词：KeywordsNanoparticlesPotential hazardous elementsEnvironmental chemistryHuman healthRailway environmentIndoor air quality
