One-year record of organic and elemental carbon in fine particles in downtown Beijing and Shanghai
1Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China
2Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
3College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
4GM R&D Center, Chemical and Environmental Sciences Laboratory, MC 480-106-269, Warren, MI 48090, USA
Abstract. Weekly PM2.5 samples were collected for one year in Beijing and Shanghai and the carbonaceous species analyzed to investigate and compare their time series patterns and possible sources in the two biggest cities of China. Weekly carbonaceous concentrations varied in wide ranges with 8.6–59 µg m-3 for OC and 1.5–25.4 µg m-3 for EC in Beijing, and with 5.1–38.4 µg m-3 for OC and 2.3–13.0 µg m-3 for EC in Shanghai. The annual average concentrations of OC and EC in PM2.5 were 23.9 and 8.8 µg m-3 in Beijing and 14.6 and 6.10 µg m-3 in Shanghai, respectively. Similar weekly variations of OC and EC concentrations were found for both cities with much higher concentrations in late fall through winter, probably due to enhanced emissions coupled with unfavorable meteorological conditions. The estimated SOC accounted for high portion of the total OC in both Beijing and Shanghai throughout the year, indicating SOC may be an important contributor to fine organic aerosol in these urban areas. In Beijing, the C14 analysis of limited samples suggested there was a significant contribution of modern carbon to the total fine carbonaceous particulate burden with higher fractions in the harvest seasons.