铜川新区采暖期PM_(2.5)浓度与气象条件关系探究

利用铜川市新区2013年11月至2014年3月PM2.5逐时浓度和距离最近的耀县气象观测站同步气象观测资料,分析了PM2.5与环境气象条件的关系,表明本区域采暖期环境气象条件对PM2.5浓度影响显著。能见度越好、日照时间越长、气温越高,PM2.5浓度越小;风速越大、混合层高度越高,大气水平和垂直扩散能力越强,PM2.5浓度亦越小;而空气相对湿度越高、云量越多,PM2.5浓度越大。风速较大时一般混合层高度也较高,大气水平和垂直扩散能力均较强,PM2.5浓度较低。5mm以上连续性降水过程对PM2.5的净化效果明显,持续多日平均风速2.3m/s以上的较大风速过程也有很好的净化效果。2.0mm以下的单日降水在风速较小时净化效果不明显,1.0mm以下的微量降水在风速较小时还会使PM2.5浓度不降反升。

Study on the Relationship between PM2.5 Concentrations and Meteorological Conditions in the Heating Period of Tongchuan New District

This paper selected hourly concentration of PM2.5 concentration from November l, 2013 to March 31, 2014 in Tongchuan new district and synchronous meteorological data in Yaoxian Station, and analyzed the relationship between PM2.5 and meteorological conditions. The results show that： （1） Concentration of PM2.5 is smaller with better visibility, longer sunshine time, higher temperature, greater wind speed, higher mixing layer height and stronger atmospheric diffusion ability. Otherwise PM2.5 is bigger with high- er relative humidity and more cloud cover. （2） When wind speed is higher, the mixing layer height also is higher. Then atmospheric horizontal and vertical diffusion ability are stronger and concentrations of PM2.s are significantly lower. （3） There are obvious purification effects with more than 5ram continuous precipi- tation process and large wind speed process which average wind speed is over 2. 3m/s. But when wind speed is small, the purification effect is not obvious with daily precipitation below 2.0 mm. The concentrations of PM2.5 increased rather than decreased in trace precipitation under 1.0 mm when wind speed is low.