Emission, Fate and Exposure Risk of Polycyclic Aromatic Hydrocarbons in China

An Euler atmospheric transport model was applied to model the near ground atmospheric concentration of polycyclic aromatic hydrocarbons (PAHs) in China based on a high-resolution emission inventory. The results were used to assess inhalation exposure and lung cancer risk of Chinese population. Monte Carlo simulation was conducted to address the uncertainty and variability in exposure concentration, intake rate and cancer risk. Frequency distributions of inhalation rate and lung cancer susceptibility were used for the simulation. For the latter, the frequencies of various genotypes for genes associated with the metabolism of PAHs and DNA repair were collected and a dose-response relationship between the number of at-risk alleles and DNA adduct level was derived from the literature. The distribution of the risk-related genotypes was transformed to the distribution of DNA adduct level as an indicator for individual susceptibility. It was found that the means of the total PAH concentration and banzo[a]pyrene equivalent concentration were 200 (106∼370 as interquartile range, IR) ng · m

−3

and 2.43 (IR 1.29∼4.50) ng · m

−3

, respectively. 5.8% (IR 2.0%∼11%) of territory where 30% (IR 17%∼43%) of population live, exceeded the national standard for PAHs. The calculated extra life-long lung cancer morbidity of Chinese population due to inhalation exposure to PAHs was 51.5×10

➄

(IR 27.3×10

−5

∼95.3×10

−5

). Due to interindividual viabilities in inhalation rate and susceptibility, size of the populations with very low or very high lungcancer risk increased and the size of population with PAH induced extra lung-cancer morbidity greater than 100×10

−5

were 11% (IR 3.3%∼24%) and 22% (IR 15%∼32%) with or without taking the inter-individual viabilities into consideration.