BTEX and formaldehyde levels at a suburban site of Agra: Temporal variation, ozone formation potential and health risk assessment

Benzene, Toluene, Ethyl-Benzene, Xylene (BTEX) and Formaldehyde (HCHO) are volatile organic compounds (VOCs) having adverse effects on air quality and on human health. Limited studies reporting BTEX and Formaldehyde concentrations and assessing their human health risk are available for India. The present study investigates the BTEX and HCHO concentrations and their carcinogenic and non-carcinogenic risk to humans at a suburban site of Agra during January 2017–December 2019. The average concentration of ΣBTEX was 80.2 ± 20.8 μg/m 3 ranging from 37.9 to 151.8 μg/m 3 with Benzene concentration exceeding National Ambient Air Quality Standards (NAAQS) annual limit. Diurnal pattern of BTEX showed morning and evening peaks while Formaldehyde showed higher concentrations during afternoon. Higher concentrations of BTEX were observed during the winter season however, Formaldehyde showed higher concentrations during summer season. B/T ratio suggested vehicular emission may be the primary source of VOCs at the study site. Among BTEX, Toluene showed maximum ozone forming potential (OFP). The cancer risks for Benzene and Formaldehyde were higher than 1 × 10 −6 (more than the acceptable value). Hazard index for BTEX were within acceptable limit while for Formaldehyde health quotient was 1. • Annual average concentration of Benzene exceeded NAAQS limit. • Toluene showed maximum ozone forming potential. • Carcinogenic risks of Benzene and Formaldehyde were higher than the acceptable value (1 × 10 −6 ). • Non-carcinogenic risk of BTEX was under the acceptable range (HI < 1).