Emission inventory and distribution characteristics of atmospheric polycyclic aromatic hydrocarbons in a coking industry city in Northern China

The sources of 16 polycyclic aromatic hydrocarbons (PAHs) in Linfen, a coking industry city in Northern China, were studied. The overall emission amount for these 16 PAHs in 2013 in Linfen was 825.12 t, with 149.22 t identified as carcinogenic PAHs. The emission intensity of PAHs in 2013 was about 40.7 kg/km(2) in Linfen, which was much higher than the average intensity found in China in 2013. Most of the PAHs were generated from the combustion of domestic, industrial, and coke-production coal, accounting for 78.6% of the total emission amount. Among the emissions of these 16 PAHs, two-and three-ring PAHs made up the majority (68.15%). In the different areas (17 in total) of Linfen, the PAH emissions ranged from 143.35 t in Hongdong County to 2.64 t in Daning County. There was a positive correlation between the rural population and total PAH emissions (R-2 = 0.794). The estimated 16 PAH emissions in Linfen from 1995 to 2013 based on historical energy consumption data showed that the amount of PAH emissions has been gradually increasing.