Park, SS, Lee, KH, Kim, YJ, Kim, TY, Cho, SY, Kim, SJ (2008). High time-resolution measurements of carbonaceous species in PM2.5 at an urban site of Korea. ATMOSPHERIC RESEARCH, 89(2-Jan), 48-61.
A Sunset Laboratory carbon analyzer with 1-hour time resolution was used to measure organic carbon (OC) and elemental carbon (EC) in fine particles (PM2.5) at an urban site of Incheon, Korea between August and October 2004. Hourly EC measurements yielded an average diurnal pattern that peaked during the morning rush hour traffic on weekdays but not on weekends. However, OC concentrations showed no significant diumal patterns during the weekday/weekend. Conditional probability functions were used to identify likely local emission source locations of the EC and OC observed at the site, indicating that the EC and OC contributions to the site were mostly coming from the northerly and southerly directions, where two heavy traffic highways and residential area are located. Throughout the study period, numerous short-term excursions of the EC and OC data were identified, but only two distinct carbon elevated events are discussed in this study. The potential source contribution function (PSCF) analysis, which combines hourly EC and OC data with air mass backward trajectories, is performed to help identify the likely source locations and the preferred pathways that cause the two carbon pollution events. One is associated with high ozone episode occurred in the afternoon, resulting in accumulation of secondary organic aerosol. During the high ozone pollution period, the high PSCF values for EC and OC are related to local source and upwind pollution areas. The other was strongly associated with long-range transport of smoke plumes from fires in northern China and southeastern Russia, leading to high enrichment of OC concentrations at the site. This event is clearly observed in the PSCF maps for EC and OC. There was a good correspondence between the hotspot locations identified based on MODIS satellite image data and the high PSCF valued grid cells. (C) 2008 Elsevier B.V. All tights reserved.