北京的空气质量尤其是夏天经常出现的霾天污染状况,是奥运期间全世界共同关注的问题。2008年8月奥运 期间,中国科学院开展了北京及周边地区奥运大气环境监测工作,具体包括地面连续点监测、地基监测和卫星遥感监测 等不同形式的监测。卫星监测可以获得霾天大区域分布的范围和光学厚度状况；遥感所超级站监测结果显示奥运期间北京 及周边地区霾天的平均水汽含量为68.84%,只比非霾天的64.61%高4.23%。地基监测结果还表明：霾天光学厚度大多 在1.0以上,能见度基本在5 km左右; 8月非霾天可吸入颗粒物浓度PM[EQUATION]和PM[EQUATION]浓度分别为 29.58 [EQUATION]g/m[EQUATION]和76.05 [EQUATION]g/m[EQUATION], 但霾天的PM[EQUATION]和PM[EQUATION]浓度则分别为68.08 [EQUATION]g/m[EQUATION]和178.81 [EQUATION]g/m[EQUATION]。NO[EQUATION]对流层柱浓 度监测结果表明,北京市城区仍然 是NO[EQUATION]主要排放源,和天津、唐山,以及河北、山东、山西、河南等地部分地区共同构成NO[EQUATION]对流层柱浓度高值区。根据监测结果分析 和模式风廓线后向轨迹数据等分析,北京霾天是在充足的水汽和稳定的大气环境条件下,可溶性细粒子经过吸湿增长 后促使能见度急剧下降而成。如超级站的监测结果表明PM[EQUATION]的质量消光截面在空气相对湿度达到95%时有一个迅速增大的过程。

A world-wide attention has been paid to the air quality during the Beijing Olympic Games, especially the air pollution during the haze days. In order to monitor the air quality during Olympic Games, a project of Knowledge Innovation Program of Chinese Academy of Sciences, named as ‘Union Action Plan for Air Quality Monitoring and Forecasting During Olympic Game in Beijing and its Surround Area’, was carried out in Beijing in 2008. Different techniques have been used, including the ground-based [EQUATION]-[EQUATION] measurements, ground-based remote sensing and satellite measurements. The results demonstrated that the haze distribution on a regional scale can be derived from satellite measurements, and the relative humidity of 68.84% during the haze days in Beijing is only 4.23% larger than that during the non-haze days. Measurements from the Super Station at the Institute of Remote Sensing Applications (IRSA) revealed that the visibilities were about 5 km during the haze days, and the haze aerosol optical depths were mostly more than 1.0 during last August. The ground-based measurements from Beijing and its surrounding stations show that the averaged PM[EQUATION] and PM[EQUATION] mass densities were 68.08 [EQUATION]g/m[EQUATION] and 178.81 [EQUATION]g/m[EQUATION] during the haze days respectively, while the corresponding values are 29.58 [EQUATION]g/m[EQUATION] and 76.05 [EQUATION]g/m[EQUATION] during the non-haze days. The measured total column densities of NO[EQUATION] are far below the national standard, however, the space-borne observation by OMI/Aura showed high values in several areas in North China, including Beijing, Tianjin, Tangshan and some regions located in Shandong, Hebei, Shanxi and Henan provinces. Further analysis to the monitoring data and the backward track trajectory of wind profile indicated that the formation of haze in Beijing is mostly resulted from the wet growth of fine solution particulates under the stable atmospheric conditions with a plenty of water vapor, consequently leading to the rapid decrease of the visibility. As an evidence, a rapid increase of the PM[EQUATION] mass extinction across section was noticed that when the relative humidity is up to 95% from the measurements at the Super Station.