Evaluation of Atmospheric Pollutants in Asphalt Plants

Asphalt plants are industrial units for asphalt mixture production that involve the burning of fossil fuels. This work aims to evaluate the impact of an asphalt plant on air quality through models generated in the computer programme AERMOD. The asphalt plant is located in a metropolitan area of a city in Brazil. Three scenarios were evaluated considering different pollutants (total suspended particulate matter (TSP), NO2 and SO2), plants (batch and drum) and fuels (diesel oil (D) and natural gas (NG)). In each scenario, the dispersion plume was traced to verify the scope of the impact on air quality. Short-term (one hour for NO2 and 24 h for SO2 and TSP) and long-term (one year) average concentrations were analysed and compared to the air quality standard provided in the Brazilian legislation. The results showed that, in general, the concentrations of pollutants were lower than the legal limits, except for SO2 (34.34 µg/m3) in the batch plant with diesel oil as a fuel. The highest short-term pollutants concentrations in the batch plant were 122.75 µg/m3 (D) and 25.40 µg/m3 (NG) for NO2; 34.34 µg/m3 (D) and 1.8 µg/m3 (NG) for SO2; and 16.62 µg/m3 for TSP; while in the drum plant such concentrations were 56.43 (D) and 26.82 µg/m3 (NG) for NO2; 4.29 µg/m3 (D) and 1.33 µg/m3 (NG) for SO2; and 12.88 µg/m3 for TSP. The highest concentrations of NO2 occurred in winter, and those of SO2 and TSP, in spring. The highest concentrations (plumes) were found in unoccupied areas.