OC and EC Observed at Gosan Climate Observatory (GCO) and Their Seasonal Characteristics During Haze Events

Organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured with SUNSET OCEC Field Analyzer at Gosan Climate Observatory (GCO) in Jeju, South Korea from October 2009 to December 2014. The mean and 99th percentile concentrations of OC and EC were 2.0±1.4μg/m3, 6.7μg/m3, 0.7±0.5μg/m3, and 2.6μg/m3, respectively. Most of higher concentrations were observed upon haze incident. For haze events, the mean and 90th percentile concentrations of OC and EC were 4.0±3.0μg/m3, 6.9μg/m3, 1.5±0.9μg/m3, and 2.7μg/m3, respectively. In particular, the OC to EC ratio and their correlation was different from season to season. While the correlation was the best in winter from Dec. to Feb. (r=0.9), the ratio of OC to EC was the highest (3.2) in fall from Oct. to Nov. These results suggest OC and EC are robust indicator for haze occurrence and deliver its source signature that is different in each season.