Spatiotemporal variation, ozone formation potential and health risk assessment of ambient air VOCs in an industrialized city in Iran

Özet

Volatile organic compounds (VOCs) are common air pollutants that are primarily emitted by motor vehicles andthrough industrial activity and can have a significant impact on air quality and adversely affect human health.The aim of this study was to characterize benzene, toluene, xylenes and styrene (BTXS) in the ambient air ofTabriz, a city in northwestern Iran, and describe their spatiotemporal variations, ozone formation potential(OFP) and provide a health risk assessment. The measured concentrations of BTXS ranged from 0.46 to 69.32 μg/$m^3$. Diurnal variation showed a significant difference between the morning and evening concentrations, in whichthe evening values were primarily higher. Spatial analysis showed that the maximum levels of BTXS occurred inthe industrial zone. The estimated OFP values ranged from 26 to 418 and 16 to 725 in winter and summer,respectively. In addition, the mean T/B ratio was 1.84, indicating the combustion of fuel in motor vehicles as themain source of VOCs. The hazard ratio of target pollutants was lower than the limits recommended by the USEPAand WHO; however, the estimated lifetime cancer risk for benzene was 7.82 × $10^−6$, which exceeds thethreshold of 1 × $10^−6$.