PAHs/NPAHs in Northeast Asia

Airborne particulates were collected in 13 cities in Northeast Asia in winter and summer from 1997 to 2010. Polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) in the extracts from the particulates were analyzed using HPLC with fluorescence and chemiluminescence detection, respectively. Both PAH and NPAH concentrations in Beijing, Shenyang, Fushun, and Tieling, which are North Chinese cities, were substantially higher compared to those in Japanese (Kanazawa, Tokyo, Sapporo, and Kitakyushu) and Korean (Seoul and Busan) cities. However, the concentrations of PAHs and NPAHs were not significantly different between South Chinese cities (Shanghai and Fuzhou) and Japanese and/or Korean cities. About 95% of 2–3-ring PAHs and more than 99% of 2-ring NPAHs existed chiefly in the gas phase, while 4-ring PAHs and 3-ring NPAHs were in both the gas and particle phases, and the other PAHs and NPAHs were almost completely in the particulate phase. In each city, more than 80% of the total PAHs and total NPAHs were found in the fine particulate fraction (<2.1 μm). Cluster analyses and diagnostic ratios showed that the major contributors of PAHs and NPAHs were different in these cities because of their different energy consumption habits.