title: Ambient air benzene at background sites in China's most developed coastal regions: exposure levels, source implications and health risks.
abstract: Benzene is a known human carcinogen causing leukemia, yet ambient air quality objectives for benzene are not available in China. The ambient benzene levels at four background sites in China's most developed coastal regions were measured from March 2012 to February 2013. The sites are: SYNECP, in the Northeast China Plain (NECP); YCNCP, in the North China Plain (NCP); THYRD, in the Yangtze River Delta (YRD) and DHPRD, in the Pearl River Delta (PRD). It was found that the mean annual benzene levels (578-1297 ppt) at the background sites were alarmingly higher, especially when compared to those of 60-480 pptv monitored in 28 cities in the United States. Wintertime benzene levels were significantly elevated at both sites (SYNECP and YCNCP) in northern China due to heating with coal/biofuels. Even at these background sites, the lifetime cancer risks of benzene (1.7-3.7E-05) all exceeded 1E-06 set by USEPA as acceptable for adults. At both sites in northern China, good correlations between benzene and CO or chloromethane, together with much lower toluene/benzene (T/B) ratios, suggested that benzene was largely related to coal combustion and biomass/biofuel burning. At the DHPRD site in the PRD, benzene revealed a highly significant correlation with methyl tert-butyl ether (MTBE), indicating that its source was predominantly from vehicle emissions. At the THYRD site in the YRD, higher T/B ratios and correlations between benzene and tetrachloroethylene, or MTBE, implied that benzene levels were probably affected by both traffic-related and industrial emissions.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: wangxm@gig.ac.cn.
authors.forename: Xinming
authors.initials: X
authors.lastname: Wang
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: zhang_yl86@gig.ac.cn.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Sujun
authors.initials: S
authors.lastname: Lü
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Huang
authors.affiliation: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Yuesi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D001554:Benzene / Q000032:analysis*; D002681:China; D002947:Cities / Q000706:statistics & numerical data; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D012306:Risk
chemical_list: D000393:Air Pollutants; D001554:Benzene
keywords: Background; Benzene; China; Exposure; Health risk; Sources