一次沙尘过程对天津气溶胶浓度分布的影响

利用气溶胶质量浓度和数浓度监测资料以及不同高度的常规气象资料，结合后向轨迹模式，分析2011年4月30日至5月1日一次沙尘天气过程对天津城区气溶胶浓度的影响。结果表明：沙尘过程前的轻雾天气下PM1贡献了气溶胶质量浓度的96%和数浓度的99.9%以上；本次沙尘天气存在两个不同的浮尘过程，主要区别体现在细粒子浓度差异上，第一次浮尘过程PM1~2.5、PM2.5~10和PM10~100分别占气溶胶数浓度的6.5%、2.5%和0.1%，第二次浮尘过程占比则依次为11.3%、2.6%和0.01%；两次浮尘过程气溶胶粒子性质有明显差异，第一次浮尘过程中粗粒子浓度占PM10的80%以上，第二次浮尘过程风向转变为偏北风，细粒子浓度增高至40%，气溶胶由单纯的沙尘气溶胶转变为沙尘-污染气溶胶。

Influence of A Sand-dust Weather Process on Aerosol Mass Concentration and Number Concentration in Tianjin, China

Based on aerosol mass concentration and number concentration data and meteorological data at different heights and backward trajectory analysis, the influence of a sand-dust weather process from April 30 to May 1 in 2011 on aerosol concentration in Tianjin were analyzed. The results indicated as follows. In the mist process before sand-dust weather, PM1 accounted for about 96% of aerosol mass concentration and 99.9% of aerosol number concentration; PM1-2.5, PM2.5-10 and PM10-100 accounted for about 6.5%, 2.5% and 0.1% respectively of total aerosol number concentration in the first floating dust process,11.3%,2.6% and 0.01% respectively in the second floating dust process; the mass concentration and number concentration of fine aerosol under two floating dust processes were obviously different because of the increase of the ratio of fine aerosol, which resulted in change of aerosol property.