Seasonal and diurnal variations of organic carbon in PM2.5 in Beijing and the estimation of secondary organic carbon
Seasonal and diurnal variations of organic carbon in PM2.5 in Beijing and the estimation of secondary organic carbon
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DOI：
10.1029/2008jd010902
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发表时间：
2009-01
影响因子：
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通讯作者：
Peng Lin;Min Hu;Z. Deng;J. Slanina;S. Han;Y. Kondo;N. Takegawa;Y. Miyazaki;Yongjing Zhao
中科院分区：
文献类型：
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作者：
Peng Lin;Min Hu;Z. Deng;J. Slanina;S. Han;Y. Kondo;N. Takegawa;Y. Miyazaki;Yongjing Zhao
[1]2005年11月至2006年10月，利用连续热光分析仪对北京市PM2.5中的有机碳和元素碳进行了逐时测量。北京大学监测点冬季、春季、夏季和秋季的平均OC浓度分别为20 ± 19、12 ± 7、10 ± 5和18 ± 11 μgC/m3。不同的季节和昼夜模式的OC观察，其浓度显着影响的季节和昼夜变化的来源，排放率，和中尺度气象。讨论了风和降水等气象参数对OC和EC浓度的影响。冬季、春季和秋季有机碳和EC浓度相关性较好，说明它们有共同的来源;夏季有机碳和EC浓度相关性较差，尤其是下午，说明这一时期次生有机碳（SOC）的影响较为显著。利用EC示踪法估算的土壤有机碳浓度分别为2.6 ± 3.1、2.8 ± 2.4、4.5 ± 2.9和4.1 ± 4.0 μgC/m3，分别占冬、春、夏、秋季土壤有机碳总量的19%、27%、45%和23%。这一结果表明，在这个城市的位置在PM2. 5中的有机碳的相对贡献，只有在夏季的初级有机碳（POC），而在其他三个季节，OC占主导地位的POC。
[1] Organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured hourly with a semicontinuous thermal-optical analyzer in Beijing, China, during four seasons from November 2005 to October 2006. The average OC concentrations measured at Peking University (PKU) site in urban Beijing were 20 ± 19, 12 ± 7, 10 ± 5, and 18 ± 11 μgC/m3 in winter, spring, summer, and autumn, respectively. Distinct seasonal and diurnal patterns of OC were observed, and their concentrations were significantly influenced by the seasonal and diurnal changes in sources, emission rates, and mesoscale meteorology. The impacts of meteorological parameters such as wind and precipitation on OC and EC concentrations are also discussed. OC and EC concentrations were found to be well correlated in winter, spring, and autumn, indicating their common origins, while their correlation was poorer in summer, especially in the afternoon, indicating that the influence of secondary organic carbon (SOC) was significant for this period. SOC concentrations were estimated by using the EC-tracer method as about 2.6 ± 3.1, 2.8 ± 2.4, 4.5 ± 2.9, and 4.1 ± 4.0 μgC/m3, accounting for 19%, 27%, 45%, and 23% of total organic carbon in winter, spring, summer, and autumn, respectively. This result showed that the relative contribution of SOC to OC in PM2.5 at this urban location was only comparable to that of primary organic carbon (POC) to OC in summer, while in the other three seasons, OC was dominated by POC.