Characteristics of Atmospheric Particulate Organic Carbon and PAHs in Chuncheon during Cold Season

This study was conducted to identify the concentration characteristics of organic carbon (OC) and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 in Chuncheon, Korea. Average PM2.5 concentration was 25.1 +/- 15.1 mu g m-3, and high PM2.5 episodes exceeding 35 mu g m-3 were observed in December and January. OC/EC ratio at the study site was relatively higher than in other region, and the contribution of secondary OC (SOC) to total OC increased as OC/PM2.5 fraction increased. In addition, SOC concentration increased as wind speed decreased. These results suggest that low wind speed in this city causes atmospheric stagnation and possibly promotes SOC formation. Average sigma PAHs concentration was 16.7 ng m-3, showing clear seasonal variation with much higher values in December and January than in October. Pyrene generally showed the highest contribution; however, PAHs with high molecular weight including Indeno[1,2,3-c,d]pyrene, which are predominantly emitted from mobile combustion, were enhanced during high sigma PAHs concentration episodes. Diagnostic ratios of PAHs determined that combustion of solid-fuel such as coal and biomass was important throughout the study period; however, some samples showed the significant effect of mobile source.