Source apportionment of BTEX compounds in Tehran, Iran using UNMIX receptor model

Abstract

Understanding the distribution levels and sources of volatile organic compounds (VOC), mainly benzene, toluene, ethylbenzene and xylenes (BTEX), in the ambient atmosphere is important for efficiently managing and implementing the associated control strategies. We measured BTEX compounds at an industrial location in the west Tehran city (Iran), which is highly influenced by industrial activities and traffic during the winter and spring seasons during 2014-2015. A multivariate receptor model, UNMIX, was applied on the measured data for the identification of the sources and their contributions to BTEX compounds in a highly industrialised and trafficked atmospheric environment of Tehran city. Three main groups of sources were identified. These included solvent and painting sources (e.g. vehicle manufacturing), motorised road vehicles and mixed origin sources. While the solvent and painting sources and vehicle exhaust emissions contributed to about 5 and 29% of total BTEX mass, respectively, the mixed origin source contributed to about two-third (~66%) of the remaining mass. These mixed origin sources included rubber and plastic manufacturing (39%), leather industries (28%) and the unknown sources (33%). The mean concentrations of benzene, toluene, ethylbenzene and average xylene(o, p,m) compounds were measured as 28.96±9.12 µg m-3 , 29.55±9.73 µg m-3 , 28.61±12.2 µg/m-3 and 25.68±10.58 µg m-3 , respectively. A high correlation coefficient (R 2 >0.94) was also found between predicted (modelled) and measured concentrations for each sample. Further analyses from UNMIX receptor model showed that the average weekday contributions of BTEX compounds were significantly higher during winter compared with those during spring. This higher concentration during winter may be attributed to calm wind conditions and high stability of

Formation potential and source contribution of secondary organic aerosol from volatile organic compounds

“…Factor 7 was characterized by high percentages of butanal and 1‐butanol. Butanal and BTEX were the most abundant species emitted by vehicles (Ameur‐Bouddabbous et al., 2012; Dehghani et al., 2017). Factors 2, 3, and 7 were identified as vehicle exhaust.…”

The Concentration of BTEX in the Air of Tehran: A Systematic Review-Meta Analysis and Risk Assessment

“…The concentration of BTEX in ambient air of Tehran was higher than many urban regions in the world ( Table 3 ). The inversion phenomenon was mentioned as one of the leading causes of the high concentration of BTEX in Tehran [ 37 , 38 , 40 , 42 ]. It occurs in the cold seasons that cause ambient air pollutants such as VOCs to become trapped in the surface layer of the Earth, which can result in intensifying air pollution levels [ 37 ].…”

“…In addition to the inversion phenomenon, fossil fuel consumption of old vehicles, low-quality fuel, population congestion, non-standard streets, and highways, besides several factories in the south of Tehran such as iron and steel industries, are other reasons for the high level of BTEX in Tehran city [ 37 , 38 , 40 , 42 ].…”

“…Besides, several factories are located in southern Tehran, with the emission of various pollutants into the ambient air [ 36 ]. Despite a high number of conducted studies regarding the concentration and numerous emission sources for BTEX in Tehran ambient air [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ], no systematic review and meta-analysis study has been conducted to assess the related health risks. Therefore, for the first time, in the current study, the carcinogenesis and non-carcinogenesis risks of BTEX pollutants in Tehran will be assessed by using a systematic review and meta-analysis approach.…”

Data on evaluation of AQI for different season in Kerman, Iran, 2015

“…After calculating the final daily indicators and according to Table 1 , the number of days and then the 2015 season in the five classes of standard pollution index were also determined [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] . I P = The Air Quality Index C P = The pollutant concentration C Lo = The concentration breakpoint that is ≤ C P C Hi = The concentration breakpoint that is ≥ C P I Lo = The index breakpoint corresponding to C Lo I Hi = The index breakpoint corresponding to C Hi …”