Atmospheric Concentrations, Seasonal Variations and Health Risk Assessment of PM 2.5 , PM 10 , and SO 2 in Tehran Metropolis, Iran

Abstract

Abstract This study assessed seasonal and annual variations as well as the health risks associated with exposure to PM2.5, PM10, and SO2 in the ambient air of Tehran from 2019 to 2021. The findings revealed that the average annual concentration of PM2.5, PM10, and SO2 varied from 28.24 to 32.34 µg/m3, 69.57 to 82.22 µg/m3, and 14.94 to 17.98 µg/m3, respectively. The amounts of PM2.5 and SO2 were the greatest in the west and southwest, while PM10 was the most abundant in the east and northeast which were above WHO guidelines. In exposure duration scenarios of 8 and 12 hours, the mean hazard quotient (HQ) for PM2.5 and PM10 was >1, suggesting an unacceptable risk to human health. There was no risk to human health according to the mean HQ for SO2 at all exposure periods of 3, 8, and 12 hours. Further evidence that exposure time plays a significant part in health hazards was provided by the fact that the mean HQ values of exposure to PM2.5 and PM10 in exposure times of 3 hours were both <1. The Sobol sensitivity analysis revealed that the PM2.5 concentration in HQ was the most sensitive indicator of the populace.