Spatio-temporal variations, ozone and secondary organic aerosol formation potential, and health risk assessment of BTEX compounds in east of Azerbaijan Province, Iran

The present study aims to investigate the Spatio-temporal variation of benzene, toluene, ethyl -benzene, and xylenes (BTEX), and their health risk assessments in the urban ambient air of Maragheh, Iran. Air samples were collected in the morning and evening from 15 points with low, medium, and high traffic. BTEX concentration in high traffic areas was 5.16 times higher than in low traffic areas. The highest mean concentration of BTEX was observed during the winter due to emissions from house heating, atmospheric inversion, and declined dilution of pollutants. The annual mean concentrations (lowest and highest concentration) of benzene, toluene, ethyl -benzene, xylene and BTEX were 2.29 +/- 1.07 (0.42-13.99), 5.52 +/- 2.33 (1.37-29.45), 0.8 +/- 0.32 (0.37-3.84), 4.47 +/- 1.89 (1.48-29.79), and 12.75 +/- 5.25 (3.65-74.07) mu g.m- 3, respectively. Moreover, it was observed that heavy vehicular traffic and lack of hydroxyl radicals (%OH) resulted in higher BTEX concentrations during rush hours compared to non-rush hours. The inhalation lifetime cancer risk (ILCR) for benzene and ethylbenzene in three age groups of birth to <1 year, 2 to <18, and 19 to <70 years was estimated to be in the range of 2.63 x 10-7-5.14 x 10-6 and 1.29 x 10-8-2.53 x 10-7, respectively, indicating that the ILCR value of benzene children and adults exceeded the recommended values.