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

Abstract

h i g h l i g h t sWe measured aromatic hydrocarbons at four contrasting sites in the PRD region. Diagnostic ratios were used to imply sources of aromatic hydrocarbons. Sources of aromatic hydrocarbons were apportioned by PMF receptor model. Solvent use, vehicle exhaust and biomass burning contributed over 89% AHs. Biomass burning contributed to AHs, particularly for Benzene in the rural. t r a c tAromatic hydrocarbons (AHs) are both hazardous air pollutants and important precursors to ozone and secondary organic aerosols. Here we investigated 14 C 6 -C 9 AHs at one urban, one suburban and two rural sites in the Pearl River Delta region during November-December 2009. The ratios of individual aromatics to acetylene were compared among these contrasting sites to indicate their difference in source contributions from solvent use and vehicle emissions. Ratios of toluene to benzene (T/B) in urban (1.8) and suburban (1.6) were near that of vehicle emissions. Higher T/B of 2.5 at the rural site downwind the industry zones reflected substantial contribution of solvent use while T/B of 0.8 at the upwind rural site reflected the impact of biomass burning. Source apportionment by positive matrix factorization (PMF) revealed that solvent use, vehicle exhaust and biomass burning altogether accounted for 89-94% of observed AHs. Vehicle exhaust was the major source for benzene with a share of 43-70% and biomass burning in particular contributed 30% to benzene in the upwind rural site; toluene, C 8 -aromatics and C 9 -aromatics, however, were mainly from solvent use, with contribution percentages of 47-59%, 52-59% and 41-64%, respectively.

Ambient air benzene at background sites in China's most developed coastal regions: Exposure levels, source implications and health risks

“…This implies that a larger portion of China's benzene emissions are concentrated in the densely populated coastal regions and, therefore, a large proportion of the population is exposed to elevated benzene levels in the ambient air. Previous studies in urban areas of this region, such as Beijing Zhang et al, 2012a,b;Li et al, 2014) and Guangzhou (Wang et al, 2002;Barletta et al, 2008;Zhang et al, 2013), showed much higher benzene levels when compared to those reported in Europe, or in the United States. Even early in January-February 2001, benzene was found to pose potential health risks from a survey of volatile organic compounds (VOCs) in 43 Chinese cities (Barletta et al, 2005), mostly in the eastern areas.…”

“…The orders (i-iv) were ranked by their lifetime cancer risks. (Tang et al, 2007;Zhang et al, 2013) and Hong Kong (Guo et al, 2011). Benzene at the SY NECP site (1297 ± 491 pptv) showed significantly lower mixing ratios when compared to those observed at rural Changchun in the NECP (2949 ± 1890 pptv; Liu et al, 2000).…”

“…The highly significant correlations between benzene and CO at SY NECP , YC NCP and DH PRD sites (r = 0.96, 0.92 and 0.77, respectively; p b 0.001) suggested that benzene at these sites was largely combustion-related. The toluene to benzene ratio (T/B) can be further used to differentiate various combustion sources (Barletta et al, 2005;Zhang et al, 2013). As shown in Fig.…”

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

“…As addressed in GB 20950-2007, implementation of emission control in China's bulk gasoline terminals had been just required since May 1st 2008, January 1st 2010 and January 1st 2012, respectively, for the BeijingeTianjian region, the Pearl River Delta region and the Yangtze River Delta region, which are three major densely populated and economically developed city clusters or megacities in China. Receptor modeling based on observed data had revealed that VOCs from oil evaporation contributed 7e30% in Beijing (Yuan et al, 2009;Wang et al, 2010), 15% in Shanghai (Cai et al, 2010), 4.3e7.6% in Hong Kong (Lau et al, 2010) and 5e10% in the Pearl River Delta region (Liu et al, 2008b;Ling et al, 2011;Zhang et al, 2012bZhang et al, , 2013 to the total man-made VOC emission.…”

Evident elevation of atmospheric monoterpenes due to degradation-induced species changes in a semi-arid grassland

“…Detailed cryogenic concentration steps are described elsewhere (Wang and Wu, 2008;Yi et al, 2007;Zhang et al, 2013). Briefly, 250 mL air inside the canister was first concentrated through a liquid-nitrogen cryogenic trap at − 160°C.…”