Spatial trends, health risk assessment and ozone formation potential linked to BTEX

The current study set out to examine BTEX species comprehensively in order to assess their spatiotemporal distribution, carcinogenic and non-carcinogenic health risk assessment, and ozone formation potential (OFP), source identification, and sensitivity and uncertainty analysis in the capital city of Qom, Iran. Data were gathered from 16 sampling stations in the winter and spring seasons. The average BTEX levels (Formula presented.) of both sampling periods were 22.49 (Formula presented.) for toluene, 15.2 (Formula presented.) for benzene, 12.38 (Formula presented.) for xylene, and 5.69 (Formula presented.) for ethylbenzene. Higher concentrations were observed in the city center and in the proximity of a power plant. Pollution source identification was carried out using principal component analysis (PCA). PCA and the T/B ratio both indicated that industrial sources are the primary pollution source in the spring, while, in the winter, BTEX levels were driven by traffic sources. The highest OFP was determined to be from xylene, followed by toluene, ethylbenzene, and benzene. Among the BTEX species, benzene had the highest cancer (Formula presented.) and non-cancer risk (Formula presented.) above and under the United States Environmental Protection Agency’s standard, respectively. Pollutant concentration was the most sensitive parameter followed by body weight, inhalation rate, and exposure frequency.