银川市主要污染物变化特征及其关系研究

Variation and relationship of criteria air pollutants in Yinchuan

利用2013—2019年银川市主要污染物浓度数据,分析了近年来银川市主要污染物浓度变化特征,并运用主成分分析法对主要污染物之间的关系进行研究。结果表明:近年来银川市主要污染物浓度除O_(3)逐年呈上升趋势外,其他均呈下降趋势;市区站O_(3)浓度较郊区背景站低,其他污染物市区较郊区背景站高;市区站PM_(10)和PM_(2.5)浓度超国家二级标准;除O_(3)浓度夏季高,冬季低外,其他污染物冬季高,夏季低;CO、NO_(2)、PM_(10)、PM_(2.5)浓度呈“双峰型”日变化特征,O_(3)和SO_(2)呈“单峰型”日变化特征。银川市主要污染物NO_(2)浓度与CO和O_(3)相关性显著,PM_(10)和PM_(2.5)之间相关性显著;污染物第一主成分是NO_(2)、CO和O_(3),方差贡献率达到50%以上,加之银川市O_(3)浓度逐年呈升高趋势,表明近年来银川市大气光化学污染增加。

Based on the monitoring data of concentrations of criteria air pollutants in Yinchuan from 2013 to 2019,we analyzed the variation of concentrations of criteria air pollutants in recent years and investigated the relationship among these air pollutants using the method of principal component analysis.The results showed that concentrations of all criteria air pollutants in Yinchuan decrease except for O_(3)that exhibit an increasing trend.The O_(3)concentrations observed at urban sites are lower than those observed at suburban background sites,whereas concentrations of other pollutants are relatively higher at urban sites.Both PM_(10)and PM_(2.5)concentrations at urban sites exceed the national secondary standard for air quality.Concentrations of all criteria air pollutants are highest in winter and lowest in summer,which is opposite to the seasonal variation of O_(3)concentration.The diurnal variation of CO,NO_(2),PM_(10),and PM_(2.5)shows a bimodal pattern,while the diurnal variation of O_(3)and SO_(2)exhibits a single peak.NO_(2)concentration has a significant correlation with CO and O_(3),and the PM_(10)concentration has a significant correlation with PM_(2.5)in Yinchuan.The first principal components of air pollutants include NO_(2),CO,and O_(3),with the variance contribution rate exceeding 50%.Moreover,the annual mean O_(3)concentration gradually increases,which indicates that atmospheric photochemical pollution is worsening in recent years.