Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in urban air particulates and their relationship to emission sources in the Pan–Japan Sea countries

Airborne particulates were collected in seven cities in the Pan–Japan Sea countries, Shenyang (China), Vladivostok (Russia), Seoul (South Korea), Kitakyushu, Kanazawa, Tokyo and Sapporo (Japan), in winter and summer from 1997 to 2002. In addition, particulates from domestic coal-burning heaters and diesel engine automobiles were collected in Shenyang and Kanazawa, respectively. Nine polycyclic aromatic hydrocarbons (PAHs) and four nitropolycyclic aromatic hydrocarbons (NPAHs) in the extracts from the particulates were analysed by HPLC with fluorescence and chemiluminescence detections, respectively. The PAHs were fluoranthene, pyrene (Pyr), benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene, and NPAHs were 1,3-, 1,6-, 1,8-dinitropyrenes, and 1-nitropyrene (1-NP). Mean atmospheric concentrations of PAHs in Shenyang and Vladivostok were substantially higher than those in Seoul, Tokyo, Sapporo, Kitakyushu and Kanazawa. However, the mean atmospheric concentrations of NPAHs were at the same levels in all cities except Kitakyushu. The expected seasonal variations (greater PAH and NPAH concentrations in winter than in summer) were observed in all cities. In order to study the major contributors of atmospheric PAHs and NPAHs, both cluster analysis and factor analysis were used and three large clusters were identified. Furthermore, the concentration ratios of 1-NP to Pyr were significantly smaller in Shenyang, Vladivostok and Kitakyushu and the values were close to those observed in particulates from coal stove exhaust. By contrast, in Seoul, Kanazawa, Tokyo and Sapporo the [1-NP]/[Pyr] ratio reached values similar to those of particulates released from diesel-engine automobiles. The [1-NP]/[Pyr] concentration ratio seemed to be a suitable indicator of the contribution made by diesel-engine vehicles and coal combustion to urban air particulates.