title: Investigation of outdoor BTEX: Concentration, variations, sources, spatial distribution, and risk assessment.
abstract: The aim of this study was to measure BTEX (benzene, toluene, ethylbenzene, and xylenes) concentrations in the ambient air of Tehran, the capital of Iran, and investigate their seasonal variations, probable sources, spatial mapping, and risk assessment. The concentrations of BTEX were measured using a continuous monitoring device installed in seven stations around the city. Spatial mapping procedure was conducted using the inverse distance weighting (IDW) method. Monte Carlo simulation was used to assess the carcinogenic and noncarcinogenic risks imposed by BTEX. The highest and lowest annual mean concentrations of toluene and ethylbenzene were recorded as 16.25 and 3.63 μg m(-3), respectively. The maximum (6.434) and minimum (3.209) toluene/benzene (T/B) ratio was observed in summer and winter, respectively. The spatial distribution of BTEX pollution indicated that the highest concentrations were found along the major roads because of heavy traffic. Spearman's rank correlation coefficients and concentration ratios showed that BTEX were produced by the multiemission sources. The mean of inhalation lifetime cancer risk (LTCR) for benzene was 3.93 × 10(-7), which is lower than the limits recommended by the United States Environmental Protection Agency (US EPA) and the World Health Organization (WHO). The hazard quotient (HQ), noncarcinogenic risk index, for all BTEX compounds was <1. The obtained results showed no threat of BTEX concentrations to human health. However, as the concentrations of BTEX will increase due to the rapid growth of vehicles and industrial activities, much effort is required to control and manage the levels of these compounds in the future.
authors: Department of Environmental Health, School of Public Health, Sabzevar University of Medical Sciences, Sabzevar, Iran; Department of Environmental Health, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Electronic address: m_miri87@ssu.ac.ir.
authors: Mohammad
authors: M
authors: Miri
authors: Department of Occupational Health Engineering, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran.
authors: Maryam
authors: M
authors: Rostami Aghdam Shendi
authors: Social Determinants in Health Promotion Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran; Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors: Hamid Reza
authors: HR
authors: Ghaffari
authors: Department of Environmental Health, School of Public Health, Semnan University of Medical Sciences, Semnan, Iran.
authors: Hamideh
authors: H
authors: Ebrahimi Aval
authors: Department of Environmental Health, School of Health, Kashan University of Medical Sciences, Kashan, Iran; Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors: Ehsan
authors: E
authors: Ahmadi
authors: Department of Occupational Health Engineering, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran.
authors: Ebrahim
authors: E
authors: Taban
authors: Department of Environmental Health, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors: Abdolmajid
authors: A
authors: Gholizadeh
authors: Department of Occupational Health Engineering, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran. Electronic address: mohsen.yazdani@modares.ac.ir.
authors: Mohsen
authors: M
authors: Yazdani Aval
authors: Department of Environmental Health, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors: Amir
authors: A
authors: Mohammadi
authors: Research Center for Environmental Determinants of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors: Ali
authors: A
authors: Azari
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis; D001554:Benzene / Q000009:adverse effects / Q000032:analysis*; D001555:Benzene Derivatives / Q000009:adverse effects / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D007492:Iran / Q000453:epidemiology; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D018570:Risk Assessment; D012621:Seasons; D014050:Toluene / Q000009:adverse effects / Q000032:analysis*; D014992:Xylenes / Q000009:adverse effects / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D014992:Xylenes; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene
keywords: Air quality; BTEX; Risk assessment; Seasonal variation; Spatial mapping