Perfil de metais nas partículas atmosféricas de Manaus/AM

Abstract

Atmospheric particulate matter (PMA) is one of the main airborne pollutants and is associated with several diseases of the respiratory system, cardiovascular system and neurodegenerative diseases. The MPA from biomass burning includes very small particles emitted directly or generated from the incomplete burning of the raw material. In this context, the city of Manaus has been affected continuously by the smoke from these fires during dry season, affecting its air quality. Among the harmful substances in the MPA, metals have been highlighted in recent decades due to their counterbalances, bioavailability and persistence in the environment. This work characterized the atmospheric particulate matter (PTS and PM2.5), in an urban area of the city of Manaus/AM, during the dry season of 2022 and 2023 in relation to the metal profile, using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique. Two large-volume samplers were used: one for collecting TSP and the other for PM2.5, both in quartz filters. The results evaluation and the information from dendrogram and from enrichment factors were essential to infer about the main sources of the 14 elements determined in the particulate matter samples. The chemical profile of TSP samples was similar in the two years of study. The major elements Fe>Al>Ca>Na>Cu>K came from natural sources, as shown by the low enrichment factor that indicates the main source as soil resuspension. The fine particles presented a different chemical composition in the two years of study, with the majors Ca>Na>K>Fe>Ni in 2022 and Na>K>Fe>Al>Cu>Mg in 2023. The diversity of chemical composition and the enrichment factor values indicate not only a contribution from different sources, both natural and anthropogenic of these elements, but also the influence of climatic conditions caused by the strong El Niño in 2023. Finally, this investigation of the MPA in Manaus during the dry season of 2022 and 2023 shows the necessity to monitor metal emissions into the atmosphere and to accompany seasonally the variation of their concentrations in particulate matter, enabling more effective control of potential sources and allowing the development of strategies for their mitigation.