High cancer risk from inhalation exposure to PAHs in Fenhe Plain in winter: A particulate size distribution-based study

Abstract

Fenhe Plain is a typical region polluted combinedly by coal combustion and coking activities with serious air pollution problem, especially in winter. In order to clarify the size distribution and health risk of polycyclic aromatic hydrocarbons (PAHs) in winter of the Fenhe Plain, the respirable aerosol particles (PM10) were collected by cascade impactor, and 17 PAHs were analyzed. The results showed that the average mass concentration of PM10-bound PAHs was 689.19 ng/m3, which was higher than that in many other domestic and overseas cities. The particulate PAHs mainly distributed in the <0.95 μm size range, accounting for more than 60% of the total. Under the combined influence of local emissions, low temperature, low intensity of solar radiation, dry atmosphere and Kelvin effect, naphthalene (Nap) displayed a bimodal distribution, while the rest of the 17 PAHs all followed a nearly unimodal size distribution. Wind and humidity were important factors which could influence the size distribution of PAHs. Coefficient of divergence (CD) analysis showed that PAHs between all of the sizes had a high spatial heterogeneity in source factor contributions, although diagnostic ratio indicated similar sources among them. Health risk assessment found that the lifetime cancer risk of exposure to particulate PAHs was 1693.76 parts per million people. Ultrafine particles (<0.95 μm) predominated the total carcinogenicity of the particulate PAHs, while benzo(a)pyrene (BaP), dibenzo(a,h)anthracene (DahA), benzo(b)fluoranthene (BbF), benzo(a)anthracene (BaA), benzo(k)fluoranthene (BkF) and indeno(1,2,3-cd)pyrene (IcdP) were the major carcinogenic components. Traffic exhausts contributed most to the carcinogenic PAHs, followed by coal combustion and coking. Our study can provide reference for the pollution control and residential health protection in Fenhe Plain, and bring more reasonable parameterizations to the estimation of PAHs outflow from this key region to other international regions.