Source profiles of volatile organic compounds (VOCs) measured in China: Part I

Source attributions of hazardous aromatic hydrocarbons in urban, suburban and rural areas in the Pearl River Delta (PRD) region

“…Significant correlations (p < 0.01) were observed between toluene and benzene at all sites. The T/B slopes at WQS, GEMC and HEMC were 2.49 ± 0.12, 1.77 ± 0.08 and 1.56 ± 0.08, respectively, which were between that observed in industry city Dongguan (T/B = 4.82 and 4.87) [3,5] and that of vehicle exhausts (T/B = 1.43 for tunnel and 1.94 for roadside) [23,28], and were also consistent with those previously reported at various locations in the PRD region [5,25,26,28,72]. T/B slopes closer to that of vehicle exhausts at GEMC and HEMC in fact reflected the fact that vehicle exhausts were the sources much more important in the urban commercial/business/dwelling areas like GEMC and its downwind areas like HEMC.…”

“…The number of LPG-driven buses and taxies in Since toluene is widely used as solvent and benzene's use is forbidden in industry, very high toluene to benzene ratios (T/B) were observed in typical industry emissions [28,68]; and T/B ratios in industrial cities [3,5] were comparatively higher than that in vehicle exhausts and roadside air samples [23,28,69,70] in which traffic-related emissions had dominant contributions. Biomass burning or coal burning showed much lower T/B ratios [66,71,72]. Reaction with OH radical was the major pathway for the removal of aromatics in ambient air [73].…”

Species profiles and normalized reactivity of volatile organic compounds from gasoline evaporation in China

“…As indicated by the study of Harley et al (2000), headspace vapor from different grades of gasoline had quite similar hydrocarbon compositions or normalized activities; previously study about gasoline headspace vapors (Na et al, 2004;Liu et al, 2008a) or emission inventories did not make a discrimination of different grades of gasoline. Therefore, for the convenience of the use of our measured results, in the present study vapors or liquid gasoline compositions for grade 97# and 93# gasoline were pooled together and we report average weight percentages and their ranges (Table 1).…”

“…Although focus has been always put on estimating VOC emission rates, species profiles are also very important for studying the health/ecological effects and atmospheric activity of VOCs emitted. To obtain species profiles for VOC emission from gasoline distribution, we should mainly consider three categories of emissions: headspace vapor typical of storage tanks' loss as measured previously by Na et al (2004) and Liu et al (2008a); gasoline compositions typical of spillage/leakage loss as measured previously by Schauer et al (2002); and more importantly vapor evolved as a result of splashing and turbulence during filling vehicle tanks. Till present the speciation of VOCs from oil evaporation is quite limited in China (Liu et al, 2008a).…”

“…To obtain species profiles for VOC emission from gasoline distribution, we should mainly consider three categories of emissions: headspace vapor typical of storage tanks' loss as measured previously by Na et al (2004) and Liu et al (2008a); gasoline compositions typical of spillage/leakage loss as measured previously by Schauer et al (2002); and more importantly vapor evolved as a result of splashing and turbulence during filling vehicle tanks. Till present the speciation of VOCs from oil evaporation is quite limited in China (Liu et al, 2008a). The present study was designed to chemically characterize the above-mentioned three types of evaporative emissions related to current gasoline distribution in China, in order to check if these species profiles are consistent with those in other regions, to obtain measured gasoline evaporation source profiles necessary for source attribution and apportioning using receptor models such as chemical mass balance (CMB) (Watson et al, 2001;Borbon et al, 2003), and to assess related hazardous effects and potentials to form secondary pollutants like ozone (Harley et al, 2000).…”