| 北京奥运时段河北香河大气污染观测研究 |
| 摘要点击 3341 全文点击 3404 投稿时间：2009-03-05 修订日期：2009-04-29 |
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| 中文关键词 北京奥运会 大气污染 SO2 NOx O3 PM2.5 PM10 香河 |
| 英文关键词 Beijing 2008 Olympic Games atmospheric pollution SO2 NOx O3 PM2.5 PM10 Xianghe |
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| 中文摘要 |
| 为监测评估周边地区大气污染对北京的可能影响,2008年6～9月北京奥运时段,在北京东南方向河北香河开展了大气污染物SO2、NOx、O3、PM2.5和PM10的连续在线观测,结合地面气象资料和HYSPLIT轨迹模式探讨了污染物的来源与传输过程.结果表明,香河地区大气污染较为严重,上述污染物观测期间日均最高值（日均值±标准差）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）μg·m-3,特别在奥运会开幕前后的7月20日～8月12日之间出现了2次持续污染过程,导致O3和PM10分别超过国家二级标准46 h（超标率9%）和11 d（46%）,PM2.5则超过美国 EPA标准18 d（75%）.奥运时段8～9月的大气污染物日均值较6～7月日均值有明显降低：SO2从27.7 μg·m-3下降到5.8 μg·m-3;NOx从18.6 μg·m-3下降到13.2 μg·m-3;O3从96 μg·m-3下降到80 μg·m-3;PM2.5从90 μg·m-3下降到60 μg·m-3;PM10从127 μg·m-3下降到106 μg·m-3.NOx、PM2.5和PM10统计（月为单位）日变化为双峰型,峰值分别出现在07:00和20:00左右;臭氧呈单峰型,峰值出现在14:00～16:00之间.香河地区大气污染受局地排放和外源输送共同影响,持续的偏南气流易造成污染物积累,而偏北气流有利于污染物扩散,降水可明显清除大气中的污染物质.通过计算7月20日～8月12日香河和北京奥运村PM2.5小时平均浓度之间的超前相关系数,发现香河超前北京6～10 h时相关性较大（0.57<r<0.65,p=0.01）,最大相关系数出现在超前8 h,表明上述时间段内香河实时观测数据对北京大气PM2.5污染超标事件可能具有预警作用. |
| 英文摘要 |
| 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,NOx,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,NOx,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) μg·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,NOx,O3,PM2.5 and PM10 decreased from 27.7,18.6,96,90,127 μg·m-3 in June-July to 5.8,13.2,80,60,106 μg·m-3 during Olympic Games (August-September),respectively. The typical diurnal variations of NOx,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. |
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