AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Source Apportionment of EC and OC in Beijing: Comparison between 14C Measurement and Chemical Transport Model
YU MORINO, Toshimasa Ohara, Shuichi Hasegawa, Akihiro Fushimi, Miyuki Kondo, Masao Uchida, Kiyoshi Tanabe, Kazuyo Yamaji, Bin Zhao, Jiayu Xu, Jiming Hao, National Institute for Environmental Studies
Abstract Number: 159 Working Group: Source Apportionment
Abstract For the source apportionment of carbonaceous aerosols, combined analysis using radiocarbon (14C) measurement and chemical transport model (CTM) is effective (Morino et al., EST, 2010). Concentrations of fine-mode aerosols, including elemental carbon (EC), organic carbon (OC) and 14C, were observed with a time resolution of 6 hours near the urban center of Beijing in June 2010. We evaluated the model performance of CTM (CMAQ v4.6, Byun and Schere, AMR, 2006) on simulation of EC and OC. The CTM well reproduced the diurnal variation of ozone and EC, while it largely underestimated OC concentration. From sector-based tag simulation, we directly compared observed and simulated TC (=EC+OC) from fossil and nonfossil sources. Fossil-TC was well reproduced by the CTM during nighttime and largely underestimated during daytime. By contrast, nonfossil-TC concentration was underestimated both during daytime and nighttime. This result suggests that the CTM largely underestimated fossil-secondary-OC (SOC) during daytime assuming EC to primary-OC (POC) ratio from fossil sources to be correct. Underestimation of nonfossil-TC suggests that the CTM underestimated POC from biomass burning or cooking and/or biogenic SOC. Further studies on their validation and model improvement are necessary. The CTM indicated that contributions from nonfossil sources were 20% and 60% to EC and POC, suggesting that biomass burning and domestic burning had important contributions to POC in Beijing. Emissions outside Beijing contributed by 25% and 50% to EC and POC.