Assessment of health risk and burden of disease induced by exposure to benzene, toluene, ethylbenzene, and xylene in the outdoor air in Tehran, Iran.

Abstract

The health risk and burden of disease induced by exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) in the outdoor air in Tehran, 2019 were assessed based on the data of five fixed stations with weekly BTEX measurements. The non-carcinogenic risk, carcinogenic risk, and disease burden from exposure to BTEX compounds were determined by hazard index (HI), incremental lifetime cancer risk (ILCR), and disability-adjusted life year (DALY), respectively. The average annual concentrations of benzene, toluene, ethylbenzene, and xylene in the outdoor air in Tehran were 6.59, 21.62, 4.68, and 20.88 μg/m3, respectively. The lowest seasonal BTEX concentrations were observed in spring and the highest ones occurred in summer. The HI values of BTEX in the outdoor air in Tehran by district ranged from 0.34 to 0.58 (less than one). The average ILCR values of benzene and ethylbenzene were 5.37 × 10-5 and 1.23 × 10-5, respectively (in the range of probable increased cancer risk). The DALYs, death, DALY rate (per 100,000 people) and death rate (per 100,000 people) induced by BTEX exposure in the outdoor air in Tehran were determined to be 180.21, 3.51, 2.07, and 0.04, respectively. The five highest attributable DALY rates in Tehran by district were observed in the districts 10 (2.60), 11 (2.43), 17 (2.41), 20 (2.32), and 9 (2.32), respectively. The corrective measures such as controlling road traffic and improving the quality of vehicles and gasoline in Tehran could reduce the burden of disease from BTEX along with the health effects of other outdoor air pollutants.