Distribution Characteristics, Inhalation Exposure and Incremental Lifetime Cancer Risk of PM2. 5 Bounded Polycyclic Aromatic Hydrocarbons (PAHs) in a Meg-city in China

摘要: Polycyclic aromatic hydrocarbons (PAHs) are common toxic compounds in environment. Previous study showed inhalation is one of the major intake routes for human exposure to PAHs. In this study, PM_ (2.5) bounded PAHs were obtained from traffic (2 sites), industry (1 site), urban setting (10 sites) and suburban setting (2 sites) in winter and summer time in Xi'an during June and December 201~ 3. The average concentrations of Ba P were from 9.1 to 15.8 ng/m~ 3 and 1.~ 3 to 4.1 ng/m~ 3 in different settings in winter and summer. The median Ba Peq concentrations of inhalation exposure were from 255.8-1120 ng/day in suburban, and the data was from 176.6 to 986.8 ng/day in urban in wintertime, whereas it was from~ 3~ 3.9 to 160.5 ng/day and from 28.8 to 144.2 ng/day for suburban and urban residents in summertime, respectively. The average incremental lifetime cancer risk (ILCR) values for all groups in winter were from 2.~ 38× 10~(-6) to 2.6~ 3× 10~(-5) and 1.02× 10~(-6) to 2.21× 10~(-5) in suburban and urban, respectively. The average value was from 4.~ 39× 10~(-7) to 5.72× 10~(-6) and~ 3.15× 10~(-7) to 4.72× 10~(-6) for suburban and urban residents, respectively, in summer. Suburban has higher risks than in urban. And adult showed potential risks especially in winter than other age groups. The sensitivity analysis results showed that the cancer slope factor (SF) and EI were the two most important factors for all groups in winter and summer health risk assessment.