可吸入颗粒物引发的沈阳冬季污染过程研究

Research on Pollution Process Caused by Inhalable Particulates in Winter in Shenyang

多年来,可吸入颗粒物始终是造成沈阳地区大气环境污染的主要根源。为此,本文利用NCEP全球再分析资料,对其造成的一次污染过程进行了研究。结果表明:PM10上升阶段,沈阳地区气流呈气旋性切变或辐合状态,低空多为小风或静风,逆温现象明显,湿度呈上干下湿分布,有利于PM10和水汽的累积。而PM10下降阶段,地面流场平直均匀,风速较大,有助于PM10的扩散与输送。由此可知,天气系统的演变直接影响到污染物的浓度变化,温压湿风等气象要素对PM10浓度有着非常重要的影响。

Inhalable particulates has become the main source to atmosphere pollution in Shenyang area in recent years. The NCEP data was used to analyse a pollution process caused by PM10. The analysis showed that Shenyang was controlled by the uniform pressure field in front of Mongolia high for a longtime which caused the low pressure gradient, convergent or cyclonic wind and low level calm in the rising stage. Moreover the temperature inversion was strong and distribution of humidity was vertical that the higher level was drunk meanwhile the lower level was wet. Thus PM10 and vapor accumulated gradually. In the dropping stage, cold front went through Shenyang and made it locate at the joint area between high and low pressure where the isobars were very dense. So the surface flow field was steady and homogeneous and the wind speed was big which led to favourable condition for PM10 to divergent and transport, thus the PM10 concentration dropped rapidly. The coupling of large and medium weather system was the main reason of concentration change, and the meteorological elements in the weather system were also very important to it.