Abstract: Particulate matter (PM) stands out as a pollutant capable of affecting various physical- chemical cycles in the atmosphere and posing significant risks to human health. It is known that the production of energy through the burning of fossil fuels, such as coal and diesel oil, is responsible for producing increased emissions of PM over short periods of time. This burning process can contribute to the increase of heavy metals, such as mercury (Hg), in the atmosphere. The south of Brazil is the region with the largest stockpiles of mineral coal, consequently, the number of thermal power plants is higher than in the rest of the country. The aim of this study was to determine the mercury content in atmospheric PM (PM2.5 and PM10) collected near a coal-fired power station in Figueira, located in the south of Brazil. The sampling sites were determined based on wind direction, population density and mine location (site 01: at a hotel next to the thermal power plant; site 02: near the center of the municipality; and site 03: inside the coal mine). The sampling campaigns were carried out in summer (February/2023) and winter (September/2023). Low-volume dichotomous stacked filter unit (SFU) samplers were used. Collections were performed for 24-hour periods using PTFE membrane filters with pore sizes of 1 μm and 10 μm for PM2.5 and PM10, respectively. Particulate matter concentrations were measured by gravimetric analysis. For total mercury determination, 2/4 of each filter was analyzed directly by atomic absorption spectrometry using a Direct Mercury Analyzer (model DMA-80, Milestone, Italy). The results showed that particulate matter concentrations were higher in the winter period (PM2.5max = 13.77 μg/m3; PM10max = 110.38 μg/m3) compared to the summer (PM2.5max = 4.35 μg/m3; PM10max = 97.21 μg/m3), with peaks occurring mainly in downtown and at the mine. The presence of mercury was detected in PM2.5 samples at the three studied sites, in both periods (<39.33 pg/m3 Hg), and in PM10 samples at the mine during the summer and at the hotel, downtown and mine during the winter (<108.63 pg/m3 Hg).

Keywords: Air pollution, coal, mercury, PM.