First, this research introduced the characteristics of long-term variations in high PM10 concentrations from 2000 to 2010 at Guro in Seoul. 1-hour average data of PM10 was collected by the β-Ray Absorption Method. 25% data below detection limit during the 11 years. PM10 showed significant regional and spatial variation. We found that lack of influence was from the regions that with Seoul as the center to the west, instead it’s often impacted seriously by external input especially Chinese and Mongolian outflows. From yearly analysis, there was no evident change in PM10 concentration. But data presented clear monthly and seasonal variation. The highest PM10 events happened in March and April of 2002, 2003 and 2006, however, the loading of PM10 during December and February increased from 2007. This change of monthly contribution was further certified by seasonal analysis and the results showed that the concentrations of PM10 reduced in spring, early and late summer but sharply increased in winter. In addition, the high PM10 concentrations usually occurred at 187μg/m3, 123μg/m3 and 84μg/m3 by the frequency calculation. Relevant sources of these high PM10 episodes were estimated to be Nei Mongo, Gobi and northeast of China during spring according to the back trajectory of CO which is an Asian Dust indicator. Nevertheless, except for these sources, the clusters from Yangtze River regions contained abundant PM10 in winter. These air masses often brought haze weather and included a lot of NO2 and SO2 that suggested anthropogenic sources. Asian Dust originated from Gobi passed by Nei Mongol happened frequently with short duration and nowadays, Asian Dust often comes with haze from anthropogenic sources.
Second, Continuous measurement of organic carbon (OC) and elemental carbon (EC) in PM2.5 were quantified at 1 hour time resolution utilizing Sunset Laboratory Model-4 Semi-Continuous OC/EC Field Analyzer at Gosan ABC superstation during the October in 2009 to August in 2012(except July in 2010 to February in 2011). PM2.5 samples were analyzed for OC and EC using thermal-optical transmittance (TOT) with NIOSH 5040 protocol. The objective in this study was to determine the characteristics of concentration and source signature of OC and EC in PM2.5 and high occurrence of OC, EC haze phenomenon. Results showed that the average PM2.5 OC and EC were 2.0±1.6μg/m3and 0.7±0.6μg/m3, respectively, with the OC/EC ratios of 4.7±7.9. The carbonaceous aerosol was one of the key factors in the formation of haze. Local emissions were the dominant sources of OC and EC in winter and long-range transport had a significant contribution to OC and EC in PM2.5 in spring and fall in Gosan. Through the creation of haze in the fall and winter are different. Two haze episodes were found in fall during this study. One was from northeast megacities of China with the pathway from Beijing, Tianjin to Fushun. In this haze event, primary pollutants including NO2, O3 and CO were highly elevated. And impacted by vehicle emission. POC and SOC simultaneously increased. In the other haze which was included by the plume from Southeast of China, SO2 and POC increased evidently. This increase was resulted in the biomass burning. During winter haze episodes, SO2 was highly elevated, impacted by coal combustion. Also Low level temperature inversion makes the air pollution more serious. SOC (Secondary Organic Carbon) was an important component of OC mass in Gosan, representing a significant trend of secondary transformation, particularly in haze days. The ratios of SOC/OC were found to be 0.38(winter), 0.36(spring), 0.49(dry summer), 0.54(wet summer), 0.44(fall) in Gosan. High SOC/OC ratios in (dry, wet) summer haze were mainly attributed to subtropical climate (high temperature and strong sunlight) in summer, while high SOC/OC ratios in fall haze were mainly due to temperature inversion (high pollutant concentration) in fall. The mass concentrations and source distribution of PM2.5 OC,EC in Gosan from Oct.2009 to Aug,2012 was analyzed using backward trajectory cluster analysis with the Weighted Potential Source Contribution Function(WPSCF) model. Recently haze phenomenon frequently occurring in the northwestern part of China, Heavily industrial area in Northwest China such as Fushun-Anshan and East china including the Beijing-Tianjin region and Shandong peninsula were identified as high PM2.5 OC, EC.