Seasonal and diurnal variations of BTEX compounds in the semi-urban environment of Orleans, France

Abstract

Atmospheric concentrations of BTEX (benzene, toluene, ethylbenzene and xylene) were measured at a semi-urban site in Orleans, France, from October 2010 to August 2011. Air samples were collected by multi-bed adsorbent tubes. The BTEX concentrations were determined by thermal desorption-gas chromatography-mass spectrometry detector (TD-GC-MSD) technique. The average concentrations of the total measured BTEX during spring, summer, autumn and winter were 724.2, 337.4, 682.3, 823.0ppt, respectively. Maximal values for their diurnal variations usually happened during rush hours in the morning and late afternoon, and the minimal values in the daytime usually happened in around noontime. The diurnal variation of BTEX in four seasons and the correlations between BTEX and NO indicated that vehicular exhaust might be the primary source of BTEX. Benzene was found in relatively high levels and the B/T ratio was significant high in spring, indicating an irregular emission source of benzene other than traffic-related emissions.

Characteristics and health effects of BTEX in a hot spot for urban pollution

“…These high ratio values of benzene to toluene are attributed to multiple sources of benzene such as gas and petrol stations, emissions related to traffic and irregular sources, and MSW emissions that produce leachate containing BTEX (Chiriac et al, 2011; Durmusoglu et al, 2010). B/T (2.02–3.07) ratios in this study were similar to those in Orleans, France (3.22), Monterrey, Mexico (2.48), Mumbai, India (1.55–1.78), and Yazd, Iran (2.89) (Bauri et al, 2016; Jiang et al, 2017; Mosaddegh Mehrjerdi et al, 2014; Srivastava et al, 2006). In contrast, lower ratios were observed in the region of La Plata (Argentina) (0.36) (Massolo et al, 2010), Carmen (Mexico) (0.39–0.36) (Cerón et al, 2013), Rome (Italy) (0.36), Izmir (Turkey) (0.53–0.5) (Muezzinoglu et al, 2001), and Delhi (India) (0.5–0.39) (Hoque et al, 2008).…”

“…The ratio of B to T is generally utilized as an identifier for emission sources of target compounds (Hazrati et al, 2016b; Jiang et al, 2017; Masih et al, 2016; Miri et al, 2016). Table 1 compares BTEX concentrations and it various ratios in the current study versus other regions.…”

“…Vehicular exhaust is one of the most important anthropogenic sources of air pollution in the ambient urban atmosphere (Bruno et al, 2008; Kalenge et al, 2013; Saxena and Ghosh, 2012; Yurdakul et al, 2013), a major constituent of which includes volatile organic compounds (VOCs) (Bruno et al, 2008; Esteve-Turrillas et al, 2007; Han et al, 2005; Jiang et al, 2017; Kim et al, 2012; Lau and Chan, 2003; Neghab et al, 2017; Özden et al, 2008; Parra et al, 2008a; Qiu et al, 2016). An important class of VOCs is the suite of BTEX (benzene, toluene, ethylbenzene, m/pxylene, and o-xylene) species, which have been the focus of many toxicological studies (Fazlzadeh Davil et al, 2011; Halliday, 2016; Hazrati et al, 2016a, 2015; Marć et al, 2016; Rad et al, 2014; Sairat et al, 2015).…”

“…Their sources, including in this work’s study region, include vehicular exhaust, gas stations, industrial activity, landfill sites, municipal solid waste (MSW) stations, and combustion for domestic heating (Bruno et al, 2008; Carrieri et al, 2006; Chiriac et al, 2007, 2011; Correa et al, 2012; Durmusoglu et al, 2010; Jiang et al, 2017; Kim et al, 2008; Kountouriotis et al, 2014; Marć et al, 2016; Sairat et al, 2015; Terrés et al, 2010; Wu et al, 2006; Xiong et al, 2016). Past work has shown that more than 45% of total VOC emissions, such as for benzene and toluene, in Mexico City, the United Kingdom, and Los Angeles stemmed from gas stations, evaporation of petrol, and motor vehicle emissions (Correa et al, 2012; Durmusoglu et al, 2010).…”

“…The benzene-to-toluene (B/T) ratio is often applied as an index for determining the emission sources of BTEX compounds (Buczynska et al, 2009; Cheng et al, 2016; Elbir et al, 2007; Legay et al, 2011; Parra et al, 2008b). A ratio exceeding 0.5 suggests that the source of benzene is not only related to traffic but also other sources (Jiang et al, 2017; Yurdakul et al, 2013). Moreover, B/T ratios lower than 0.5 suggest that transportation is the predominant source of BTEX (Elbir et al, 2007; Hartmann et al, 1997; Zhang et al, 2008).…”