Pan Yue-Peng, Wang Yue-Si, Hu Bo, Liu Quan, Wang Ying-Hong, Nan Wei-Dong
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
Huan Jing Ke Xue. 2010 Jan;31(1):1-9.
There is a concern that much of the atmospheric pollution experienced in Beijing is regional in nature and not attributable to local sources. The objective of this study is to examine the contribution of sources outside Beijing to atmospheric pollution levels during Beijing 2008 Olympic Games. The observations of SO2, NO(x), O3, PM2.5 and PM10 were conducted from June 1 to September 30, 2008 in Xianghe, a rural site about 70 km southeast of Beijing. Sources and transportation of atmospheric pollution during the experiment were discussed with surface meteorology data and backward trajectories calculated using HYSPLIT model. The results showed that the daily average maximum (mean +/- standard deviation) concentrations of SO2, NO(x), O3, PM2.5, and PM10 during observation reached 84.4(13.4 +/- 15.2), 43.3 (15.9 +/- 9.1), 230 (82 +/- 38), 184 (76 +/- 42) and 248 (113 +/- 52) microg x m(-3), respectively. In particular, during the pollution episodes from July 20 to August 12, the hourly average concentration of O3 exceeded the National Ambient Air Quality Standard II for 46 h (9%), and the daily average concentration of PM10 exceeded the Standard for 11 d (46%); PM2.5 exceeded the US EPA Standard for 18 d (75%). The daily average concentrations of SO2, NO(x), O3, PM2.5 and PM10 decreased from 27.7, 18.6, 96, 90, 127 microg x m(-3) in June-July to 5.8, 13.2, 80, 60, 106 microg x m(-3) during Olympic Games (August-September), respectively. The typical diurnal variations of NO(x), PM2.5 and PM10 were similar, peaking at 07:00 and 20:00, while the maximum of O3 occurred between 14:00 to 16:00 local time. The findings also suggested that the atmospheric pollution in Xianghe is related to local emission, regional transport as well as the meteorological conditions. Northerly wind and precipitation are favorable for diffusion and wet deposition of pollutants, while sustained south flows make the atmospheric pollution more serious. The lead-lag correlation analysis during the pollution episodes from July 20 to August 12 showed that there are about 6-10 h (0.57 < r < 0.65, p = 0.01) of hourly average PM2.5 in Beijing lagging Xianghe, reaching the maximum at 8 h, which indicates that the real-time atmospheric PM2.5 database of Xianghe might provides early warning for the Beijing PM2.5 pollution events.
有人担心，北京经历的大部分大气污染本质上是区域性的，并非源自本地。本研究的目的是调查北京以外的污染源对2008年北京奥运会期间大气污染水平的贡献。2008年6月1日至9月30日，在北京东南约70公里处的农村地区香河进行了二氧化硫、氮氧化物、臭氧、细颗粒物（PM2.5）和可吸入颗粒物（PM10）的观测。利用地面气象数据和使用HYSPLIT模型计算的后向轨迹，讨论了实验期间大气污染的来源和传输。结果表明，观测期间二氧化硫、氮氧化物、臭氧、细颗粒物和可吸入颗粒物的日平均最大（均值±标准差）浓度分别达到84.4（13.4±15.2）、43.3（15.9±9.1）、230（82±38）、184（76±42）和248（113±52）微克·立方米⁻³。特别是在7月20日至8月12日的污染时段，臭氧小时平均浓度超过国家环境空气质量标准二级46小时（9%），可吸入颗粒物日平均浓度超过标准11天（46%）；细颗粒物超过美国环保署标准18天（75%）。二氧化硫、氮氧化物、臭氧、细颗粒物和可吸入颗粒物的日平均浓度分别从6 - 7月的27.7、18.6、96、90、127微克·立方米⁻³降至奥运会期间（8 - 9月）的5.8、13.2、80、60、106微克·立方米⁻³。氮氧化物、细颗粒物和可吸入颗粒物典型的日变化相似，在07:00和20:00达到峰值，而臭氧最大值出现在当地时间14:00至16:00之间。研究结果还表明，香河的大气污染与本地排放、区域传输以及气象条件有关。北风和降水有利于污染物的扩散和湿沉降，而持续的南风使大气污染更加严重。7月20日至8月12日污染时段的超前 - 滞后相关性分析表明，北京细颗粒物小时平均浓度比香河滞后约6 - 10小时（0.57 < r < 0.65，p = 0.01），在8小时达到最大值，这表明香河的实时大气细颗粒物数据库可能为北京细颗粒物污染事件提供预警。
