北京奥运会及残奥会期间PM10质量浓度演变特征及成因

2008年8─9月北京及周边各省市ρ(PM₁₀₎明显低于2006─2007年同期值. 结合污染物监测数据及气象资料，采用影响因子资料统计以及典型个例诊断对比法，研究造成北京奥运会及残奥会期间低ρ(PM₁₀₎的原因. 对2006─2008年同期风速的统计表明，2008年7─10月北京各月平均风速均低于往年，2 m/s以上的风发生频率低于往年，不利于大气污染物扩散. 2008年8月北京月降水量与2005年接近，但ρ(PM₁₀₎明显优于2005年，可见降水并不是该次ρ(PM10)月均值低的原因. 对比2006─2008年8─9月典型相似累积型天气型背景影响下ρ(PM₁₀₎日均值及演变过程发现，2008年ρ(PM₁₀₎日均值及演变曲线均低于往年. 根据对影响因子统计和北京及其周边省(市、区)严格的减排措施等分析，指出天气形势及其伴生的气象因素演变可能影响ρ(PM10)日均值波动，但六省(市、区)协同减排是保障优质空气质量的主要原因. 

Evolution Characteristics and Causes of PM10 Mass Concentration in Beijing During the Olympic Games and Paralympic Games Period

Daily average PM_(10) mass concentrations in Beijing and adjacent areas in August and September 2008 were significantly lower than those in 2006 and 2007. In this paper, the reasons for the low PM_(10) mass concentrations in Beijing during the Olympic Games and Paralympic Games period are studied by employing influence factor data and statistics, and using typical case diagnostic analysis with air pollution and meteorological data. Comparative analysis of wind speeds from 2006 to 2008 indicates that in Beijing from July to October 2008, the monthly average wind speed was lower than that in previous years, and the frequency of wind speeds stronger than 2 m/s was lower than in previous years. The wind speed conditions were not conducive to air pollution diffusion. The rainfall in Beijing in August 2008 was close to that in August 2005. However, PM_(10) mass concentrations in August 2008 were significantly lower than that in August 2005, suggesting that precipitation was not the reason for lower monthly average PM_(10) mass concentration. PM_(10) daily average mass concentration evolution processes under typical similar accumulative synoptic type backgrounds in Beijing during August and September from 2006 to 2008 were compared. PM_(10) daily mass concentration values and evolution curves in Beijing in 2008 were lower than those in previous years. Considering the above influence factors and the strict emission abatement measures, it is concluded that synoptic types and accompanying meteorological factors are the main causes of the daily average PM_(10) mass concentration fluctuations, while synchronous emission abatement of six provinces and cities of North China is the main factor that ensured the excellent air quality during the Olympic Games and Paralympic Games.