银川市空气污染与气象要素的相关关系研究

Study on the Correlation between Air Pollution and Meteorological Elements in Yinchuan City

为了探讨银川市空气污染物与气象要素间的关系,采用相关分析、合成分析等统计方法,研究了2018—2020年银川市空气质量的变化特征及其与气象要素的相关性。结果表明:银川市空气质量指数月变化规律基本一致,1月、5月、6月和7月空气质量指数(AQI)较大,9月和10月AQI最小;银川市空气质量等级为优的天数呈增加趋势;银川市首要污染物主要以PM_(10),O_(3),PM_(2.5)为主,O_(3)质量浓度主要在5—8月较高,PM_(2.5)质量浓度在1月、2月、11月、12月较高,PM_(10)质量浓度在1月、3月、5月、11月较高。2020年,O_(3)质量浓度较高时,850 hPa形势场上,银川处于热倒槽底部,风力较弱,相对湿度较低;PM_(10)质量浓度较高时,850 hPa形势场上,银川地区受宽广横槽影响,低层存在逆温层。银川市空气质量与气象要素垂直分布存在一定的相关性。当对流层中低层相对湿度减少时,AQI增加;当对流层整层位势高度降低、中低层气温增加时,AQI增加;当低层位势高度增加、温度降低时,AQI增加。

In order to explore the relationship between air pollutants and meteorological elements in Yinchuan City,statistical methods such as correlation analysis and composite analysis were used to study the characteristics of air quality changes from 2018 to 2020 and their correlation with meteorological elements.The results show that the monthly variation of the Air Quality Index(AQI)in Yinchuan City is generally consistent,with higher AQI values in January,May,June,and July,and the lowest AQI values in September and October.The number of days with excellent air quality levels in Yinchuan City shows an increasing trend.The primary pollutants in Yinchuan City are mainly PM_(10),O_(3)and PM_(2.5).O_(3)concentration is higher from May to August,PM_(2.5)concentration is higher in January,February,November,and December,and PM_(10)concentration is higher in January,March,May,and November.In 2020,when the O_(3)concentration was high,the 850 hPa synoptic chart showed that Yinchuan was at the bottom of a thermal trough with weak winds and low relative humidity;when the PM_(10)concentration was high,the 850 hPa synoptic chart showed that the Yinchuan area was affected by a broad trough,with a temperature inversion layer in the lower atmosphere.There is a certain correlation between air quality in Yinchuan City and the vertical distribution of meteorological elements.AQI increases when the relative humidity in the mid-lower troposphere decreases;AQI increases when the entire tropospheric geopotential height decreases and the mid-lower layer temperature increases;AQI increases when the lower layer geopotential height rises and the temperature decreases.