2007和2008年夏季北京奥运馆大气PM10与PM2.5质量浓度变化特征

为了监测北京奥运主场馆附近大气颗粒物的污染状况以及评估奥运污染源减排措施对北京大气颗粒物质量浓度变化的影响,利用颗粒物在线监测仪器TEOM于2007年和2008年夏季,在奥运主场馆附近的中国科学院遥感应用研究所办公楼楼顶对大气颗粒物PM10和PM2.5进行了连续同步观测。结果表明,2007年夏季监测点附近大气PM10与PM2.5质量浓度的平均值分别为153.9和71.2μg.m-3,而2008年夏季PM10与PM2.5质量浓度的平均值分别为85.2和52.8μg.m-3。与奥运前一年同时段相比,奥运时段大气PM10和PM2.5的质量浓度分别下降44.5%和25.1%。对比分析奥运前后的2次典型污染过程发现,空气相对湿度的增加和偏南气流输送的共同影响易造成大气颗粒物的累积增长,而降雨的湿清除作用和偏北气流则会使大气颗粒物浓度迅速降低。在相近的气象条件下,奥运前后的污染过程中,大气细粒子的日均增长速率分别为25.1和13.9μg.m-3.d-1,而大气粗粒子的日均增长速率分别为20.8和2.2μg.m-3.d-1,奥运时段污染累积过程中大气粗、细粒子的增长速率分别显著低于和略低于奥运前同时段污染过程中颗粒物的增长速率。污染源减排措施的实施是奥运期间大气颗粒物质量浓度降低的主要原因,从控制效果来看,奥运期间实施的污染源减排措施对大气粗粒子的控制效果明显好于大气细粒子。

Characteristics of PM10 and PM2.5 during summer time of 2007 and 2008 at Beijing National Stadium

In order to investigate the variation characteristics of atmospheric particle pollution in the Olympic Village and evaluate the effect of pollution control measures on particle matter concentrations,the on-line measurements of particle mass concentration（PM10 and PM2.5） using TEOM were conducted on the rooftop of a six-floor building in the Institute of Remote Sensing Applications,Chinese Academy of Sciences,during both summer of 2007 and 2008.Results show that the average mass concentration of PM10 and PM2.5 during summer of 2007 are 153.9 and 71.2 μg·m-3,while the average mass concentration of PM10 and PM2.5 during summer of 2008 are 85.2 and 52.8 μg·m-3,respectively.Compared with the same period of one year before,the average mass concentration of PM10 and PM2.5 decrease by 44.5% and 25.1%,respectively,during the Olympic Games.Two typical particle pollution processes are selected to compare the variation difference of particle mass concentrations before and during the Olympic Games.The result shows that the relative humidity increasing and air masses transportation from south regions both together easily lead to the increasing of atmospheric particles,whereas the rainfall events and air mass transportation from north regions have a great effect on the scavenging of particle matter.In the similar weather conditions,the daily growth rate of fine particles in pollution accumulation process are 25.1 and 13.9 μg·m-3·d-1,while the daily growth rate of coarse particles are 20.8 and 2.2 μg·m-3·d-1,respectively,before and during Olympic Games.The daily growth rate of coarse and fine particles in pollution process during Olympic Games are significantly and slightly lower than those in pollution process before Olympic Games,which indicates that the implementation of pollution control measures during the Olympic Games has a great effect on the decreasing of particle matter,especially on the reduction of coarse particles.