太原市近5年环境空气污染物浓度变化与趋势分析

Variations of air pollutants'concentrations during nearly 5 years in Taiyuan City

采用综合污染指数法、污染负荷系数法、Daniel趋势检验、Spearman秩相关系数法并结合空气质量指数(AQI)数据,探讨了近5 a来太原市环境空气污染物浓度变化,结果表明,2015—2019年,太原市SO_(2)的超标天数和污染物浓度均逐年下降(超标天数由50 d下降至0 d,污染物浓度由77.55μg·m^(-3)下降至29.52μg·m^(-3));而NO_(2)的超标天数和污染物浓度均逐年上升(超标天数由2 d上升至40 d,污染物浓度由43.11μg·m^(-3)升至59.81μg·m^(-3)),变化趋势显著;PM_(10)和PM_(2.5)的变化表现出一定的波动,变化趋势不显著;空气综合污染指数呈现先升高后降低的趋势,环境空气污染在冬季较为严重.可吸入颗粒物(PM_(10)和PM_(2.5))历年的负荷系数均显著高于SO_(2)和NO_(2),空气污染物以可吸入颗粒物为主.从各年AQI累积的数值之和来看,空气污染有逐渐加重的趋势.

Based on the methods of comprehensive pollution index,pollution load coefficient,Daniel trend test,Spearman rank correlation coefficient combining with air quality index(AQI)data,the variations and trends of air pollutants'concentrations during nearly 5 years in Taiyuan City were discussed.Results showed that the number of days that exceeding the standard(decreased from 50 d to 0 d)and concentration of SO_(2)(decreased from 77.55μg·m^(-3)to 29.52μg·m^(-3))both decreased from 2015 to 2019,whereas the number of days that exceeding the standard(increased from 2 d to 40 d)and concentration of NO_(2)(increased from 43.11μg·m^(-3)to 59.81μg·m^(-3))both increased year by year,the variation trends of SO_(2) and NO_(2) are remarkable.The variations of PM_(10) and PM_(2.5) showed fluctuations,and the variation trends are not remarkable.The comprehensive air pollution index(API)increased first and then decreased within the year,and the pollution in winter was more severe than other seasons.The load coefficients of PM_(10) and PM_(2.5) were significantly higher than those of SO_(2) and NO_(2) over the years,and the main air pollutants were inhalable particles.According to the sum of the values of AQI,air pollution turned out to be an increasing trend gradually.