Source-oriented risk assessment of inhalation exposure to ambient polycyclic aromatic hydrocarbons and contributions of non-priority isomers in urban Nanjing, a megacity located in Yangtze River Delta, China.
Sixteen U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) and eleven non-priority isomers including some dibenzopyrenes were analyzed to evaluate health risk attributable to inhalation exposure to ambient PAHs and contributions of the non-priority PAHs in a megacity Nanjing, east China. The annual average mass concentration of the total 16 EPA priority PAHs in air was 51.1 ± 29.8 ng/m3, comprising up to 93% of the mass concentration of all 27 PAHs, however, the estimated Incremental Lifetime Cancer Risk (ILCR) due to inhalation exposure would be underestimated by 63% on average if only accounting the 16 EPA priority PAHs. The risk would be underestimated by 13% if only particulate PAHs were considered, though gaseous PAHs made up to about 70% of the total mass concentration. During the last fifteen years, ambient Benzo[a]pyrene decreased significantly in the city which was consistent with the declining trend of PAHs emissions. Source contributions to the estimated ILCR were much different from the contributions for the total mass concentration, calling for the introduce of important source-oriented risk assessments. Emissions from gasoline vehicles contributed to 12% of the total mass concentration of 27 PAHs analyzed, but regarding relative contributions to the overall health risk, gasoline vehicle emissions contributed 45% of the calculated ILCR. Dibenzopyrenes were a group of non-priority isomers largely contributing to the calculated ILCR, and vehicle emissions were probably important sources of these high molecular weight isomers. Ambient dibenzo[a,l]pyrene positively correlated with the priority PAH Benzo[g,h,i]perylene. The study indicates that inclusion of non-priority PAHs could be valuable for both PAH source apportionment and health risk assessment.
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Shaojie
S
Zhuo
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; Jiangsu Key Laboratory of Environmental Engineering, Jiangsu Provincial Academy of Environmental Sciences, Nanjing 210036, China. Electronic address: gfshen12@gmail.com.
Guofeng
G
Shen
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
Ying
Y
Zhu
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Wei
W
Du
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Xuelian
X
Pan
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Tongchao
T
Li
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Yang
Y
Han
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Bengang
B
Li
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Junfeng
J
Liu
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Hefa
H
Cheng
Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, United States.
Baoshan
B
Xing
College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Shu
S
Tao
D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D002681:China; D002947:Cities; D006801:Humans; D019570:Inhalation Exposure; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D018570:Risk Assessment; D045483:Rivers; D001335:Vehicle Emissions / Q000032:analysis
D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions
Dibenzopyrene; Increment lifetime cancer risk; Non-priority isomers; Polycyclic aromatic hydrocarbons; Source-oriented risk assessment