中文摘要：

随着经济的发展,NO2污染日趋严重。利用OMI（Ozone Monitoring Instrument,臭氧监测仪）数据得到北京、上海、广州、武汉、西安5个城市2004年10月～2009年7月的NO2浓度月均值变化的时间序列,分析5个城市的NO2浓度变化特征。并根据2007年1月～2008年12月5个城市环境监测中心发布的NO2污染API指数,推算出近地面NO2浓度月均值,与OMI遥感数据反演的对流层柱浓度进行比较,两组数据有较一致的变化趋势。根据OMI数据得到的该5个城市2005～2008年的NO2浓度年均空间分布,发现中心城区NO2浓度值远高于郊区,形成了城市气候的＂混浊岛效应＂,这与发达的城市交通,高强度的人口活动以及城市局地流场特征有着密切的关系。通过GOME（Global Ozone Monitoring Experiment,全球臭氧监测实验）NO2浓度年均变化值和1999～2008年5城市机动车保有量的相关分析,认为机动车尾气排放量的增加是我国发达城市NO2污染的主要原因。

英文摘要：

Nitrogen dioxide（NO2）plays a key role in the chemistry of the atmosphere,and NO2 pollution is getting worse with the development of economy.Using OMI,the results of monthly averaged tropospheric NO2 change trends of Beijing,Shanghai,Guangzhou,Wuhan and Xi＇an from October 2004 to July 2009 were obtained,and their characteristics of these changes were analyzed.The monthly averaged OMI tropospheric NO2 column over these five cities were compared with the monthly averaged surface mass concentration of NO2,which were calculated according to the Air Pollution Index of NO2 for these five cities from January 2007 to December 2008.The result showed that these two sets of data had the same change trend.Furthermore,the OMI was also used to gain the distribution map of annual average NO2 concentration of the downtown in these five cities from 2005 to 2008.It was found that the downtown NO2 concentration was much higher than rural areas,and this formed the turbid island effect in the urban climate.These were closely related to developed city traffic,high population activity and the urban heat island circulation.In addition,annual averaged GOME tropospheric NO2 were compared with the number of vehicles of the five cities in the 10-year period from 1999 to 2008.These analysis results showed that high correlation coefficients were obtained between the vehicle exhaust emissions and NO2 pollution.