巴中市城区PM_(2.5)污染特征及时空变化规律分析

Pollution Characteristics and Spatial and Temporal Distribution Variations of PM_(2.5) in Bazhong City

利用巴中市城区一个自然年(2016年3月1日~2017年2月28日)的空气质量数据,分析了巴中市城区PM_(2.5)的污染特征和时空变化规律。结果表明,PM_(2.5)日均浓度对数值接近正态分布特征,PM_(2.5)与其他主要大气污染物都具有显著的相关关系。CO、NO_2是主要的相关因素,与PM_(2.5)的相关系数都高达0.7以上。PM_(2.5)浓度表现为冬季>秋季>春季>夏季,这与首要污染物是PM_(2.5)的天数占比以及PM_(2.5)与PM_(10)相关系数的季节变化一致,反映了PM_(2.5)呈现出以冬季污染最重,春、秋季污染中等,夏季污染最小的季节特征。PM_(2.5)与PM10的浓度比值表现为冬季>秋季>夏季>春季。各个站点的PM_(2.5)变化趋势一致,相互之间浓度差异小且比较均衡,巴中中学站点的PM_(2.5)浓度无论在任何季节都高于其他站点,苏山坪站点在冬季的PM_(2.5)浓度明显低于其他站点,表明PM_(2.5)污染具有明显的区域性特征,与人类活动强度相关的局地污染对PM_(2.5)污染具有一定影响。

Based on the air quality data from Mar. 1 th,2016 to Feb. 28 th,2017 of Bazhong city,this paper analyzed the pollution characteristics and spatial and temporal distribution variations of PM2.5 in Bazhong City. The results showed that PM2.5 concentration of Bazhong present an approximately log-normal distribution. The other main air pollutants showed significant correlations with PM2.5,as main related factors,the correlation coefficients for CO,NO2 and PM2.5 were over 0. 7. The seasonal average concentrations of PM2.5 in descending order were winter,autumn,spring,summer,while the seasonal percent of days and pollution days which PM2.5 is the primary pollutant of atmosphere pollution and the correlation coefficients for PM2.5 and PM（10） were in a similar order,indicating that the PM2.5 pollution is heavy in winter,moderate in spring and autumn,and mild in summer. The seasonal average PM2.5/PM（10） ratio in descending order were winter,autumn,summer,spring. The variation trend of PM2.5 concentration in each monitoring station is same,their differences are small and even. PM2.5 concentration in Bazhong middle school is higher than any other stations in any season,PM2.5 concentration in Sushanpin is lower than any other stations in winter,indicating that PM2.5 pollution has obvious regional characteristics,the emission of local pollution related to human activity intensity has certain influence on PM2.5 pollution.