Exposure to high levels of PM2.5 and PM10 in the metropolis of Tehran and the associated health risks during 2016-2017

This study provides the daily, seasonal and annual variations and the related human health risk assessment from exposure to PM2.5 and PM10 in the ambient air of Tehran from January 2016 to December 2017. The hourly PM2.5 and PM10 data of ten selected air quality monitoring stations was acquired from Tehran air quality control center. The results showed that, annual mean concentrations of PM2.5 and PM10 in the selected stations varied from 22.6 to 39.5 mu g/m(3) and from 62.5 to 104.3 mu g/m(3), respectively. However, Tehran citizens were exposed to concentrations of annual PM2.5 and PM10 exceeding the WHO air quality guideline (AQG), US Environmental Protection Agency (USEPA) and Iranian standard levels during the study period. The mean of hazard quotient (HQ) for PM2.5 (6.3) and PM10 (1.6) in all age groups were > 1, indicating an unacceptable risk for human health. Also, the mean of Excess Lifetime Cancer Risk (ELCRs) for PM2.5 in different age groups in 2016 and 2017 varied from 3.7x10(-6) to 276.9x10(-6) and from 4x10(-6) to 306.4x10(-6), respectively, which exceeds the limit value set by the USEPA and WHO. Based on this study, ambient air can be a potential source for exposure to PM10 and PM2.5 and increase the risk of respiratory diseases and cardiovascular problems among exposed people. Therefore, proper control policies are recommended to protect public health in this metropolitan area.