上海地区大气相对湿度与PM10浓度和大气能见度的相关性分析

以大气RH(相对湿度)为基准对上海2005─2009年大气质量和气象资料的日均观测资料进行了分类统计,分析了RH与ρ(PM10)、大气能见度的相关关系.结果表明:在将RH以5%的间隔进行分段后,各区段ρ(PM10)平均值与RH平均值呈显著线性负相关,R(相关系数)达0.97;随着RH增大,大气能见度随ρ(PM10)变化率的绝对值增大;RH在75%以上时,增加相同的ρ(PM10)所导致的大气能见度下降量是RH在40%～45%时的5倍以上;RH小于75%时,大气能见度可较好地反映ρ(PM10)的变化,而RH大于75%时,大气能见度的降低主要反映PM10含水量的快速增加而并不指示ρ(PM10)的增加.

Relationships among Relative Humidity, PM10 Concentration and Atmospheric Visibility in Shanghai

The relationships among relative humidity,PM10 mass concentration and atmospheric visibility were investigated using reorganized daily air quality and meteorological data for Shanghai during 2005-2009.When the data were sorted and averaged over 5% intervals of relative humidity,a strong negative correlation(R=0.97) was found between PM10 concentration and relative humidity.It was found that the rate of change of visibility versus PM10 increased with increasing relative humidity.With relative humidity above 75%,the visibility degradation caused by the increase of a certain amount of PM10 was five times higher than that at 40%-45% relative humidity.When the relative humidity was below 75%,the expected negative correlation was found between visibility and PM10 concentration.However,when the relative humidity was higher than 75%,visibility degradation mainly indicated the rapid increase of water uptake by the particles,which may not be a real indication of the increase in PM10 concentration.