Temporal trend of the major contributors for the particulate polycyclic aromatic hydrocarbons (PAHs) in Seoul

To evaluate the effectiveness of the air quality management policies in Northeast Asia, especially in China and South Korea, temporal variation in the major contributors of the observed particulate polycyclic aromatic hydrocarbons (PAHs) in Seoul between 2002 and 2013 was estimated via receptor modeling. In addition, analyses of the air parcel movement and the statistics related to energy usage and PAH emissions in the region were conducted to validate the modeling results. Five factors were identified: coal usage for coke ovens, residential coal use, vehicular emission, biomass burning, and other emission sources. It was found that the PAH concentration in the ambient air in Seoul has been affected not only by domestic emissions but also by transported PAHs originating outside Korea, such as emissions from coal use in China and biomass burning in Northeast Asia. In addition, the impact from North Korea was verified for the PAHs emitted from biomass burning. The contribution of coal combustion decreased while that of vehicular sources increased during the study period; the contribution from biomass burning, however, remained consistent. Despite uncertainties in the modeling results, which are discussed in this paper, this study demonstrates that the air quality management policies in China and South Korea have been successful in reducing particulate PAH emissions.