Volume 12, No. 5, October 2012, Pages 792-802 PDF(694 KB)
Characterization of Atmospheric Organic and Elemental Carbon of PM2.5 in a Typical Semi-Arid Area of Northeastern China
Renjian Zhang1,2, Jun Tao3, K.F. Ho2,4, Zhenxing Shen5, Gehui Wang2, Junji Cao2, Suixin Liu2, Leiming Zhang1,6, S.C. Lee7
1 RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
2 SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
3 South China Institute of Environmental Sciences, Guangzhou 510655, China
4 School of Public Health and Primary Care, The Chinese University of Hong Kong, Hongkong, China
5 Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
6 Air Quality Research Division, Environment Canada, Toronto, Canada
7 Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hongkong, China
In the spring of 2006, daily particulate matter (PM2.5) aerosol samples were collected in Tongyu, a semi-arid area in northeastern China. The concentrations of organic carbon (OC) and elemental carbon (EC) were determined with a thermal/optical carbon analyzer in the filter samples. The average concentrations of OC and EC in PM2.5 were 14.1 ± 8.7 and 2.0 ± 1.3 μg/m3, respectively. A good correlation between OC and EC was observed during the spring season, suggesting that they might be derived from similar sources. The correlation between OC and K+ was high (R = 0.74), and the K+/OC ratio, as determined from their linear regression slope, reached 2.57. The good correlation and high K+/OC ratio indicated that biomass-burning was probably one of the major sources of OC in this region. The concentrations of estimated secondary organic carbon (SOC) in PM2.5 in Tongyu ranged from below the detection limit to 26.1 μg/m3 (mean, 5.9 μg/m3). The percentages of SOC in OC and in PM2.5 mass were 42.0% and 2.1%, respectively. The SOC concentrations during dust storm (DS) periods were higher than those during non-dust storm (NDS) ones, suggesting that chemical reaction processes involving gas-particle conversion occurred during the long-distance transport of aerosol particles.
Semi-arid area; Organic carbon; Elemental carbon; Dust storm.