成都市PM2.5、PM10变化特征及其与气象因素的关系

为研究气象因素对成都市大气细颗粒物 (PM2.5)、可吸入颗粒物 (PM10) 的影响， 收集了2015―2018 年成都市 PM2.5、PM10的月平均浓度， 采用Pearson 相关分析法， 分析了成都市PM2.5、PM10与气象条件的关系。结果表明： (1) 2015 ―2018 年， 成都市PM2.5、PM10年平均浓度虽然年际间差别较小， 但整体呈现逐年缓慢下降趋势， 2015 年以来成都市的 一系列大气污染控制措施是PM2.5、PM10逐年缓慢下降的原因； 2015―2018 年成都市PM2.5、PM10浓度季节变化特征整体 表现为冬季 > 春季 > 秋季> 夏季。(2) 不同气象因素对成都市PM2.5、PM10月平均浓度的影响程度不同， 降水量与气温 是影响成都市PM2.5、PM10月平均浓度的主要因素， 两者与PM2.5、PM10呈较高的负线性相关， 其中PM2.5、PM10与降水量 的相关系数均为 ?0.612， 与月平均气温的相关系数分别为 ?0.822、?0.776， 降水会通过捕获大气中的颗粒物来去除 PM2.5、PM10， 而温度的升高会加强PM2.5、PM10等污染物在垂直方向上的对流运动， 从而对成都市污染物浓度的降低起 到重要作用； 日照时数、月平均风速、相对湿度等与PM2.5、PM10月平均浓度整体也呈现负相关， 但与降水量和气温相 比， 日照时数、月平均风速与PM2.5、PM10月平均浓度的相关性较低， 而相对湿度与PM2.5、PM10月平均浓度的相关性则 更加微弱， 表明相对湿度的变化对成都市PM2.5、PM10的积累和扩散影响很小。

Variation characteristics of PM2.5 and PM10 in Chengdu and their correlation with meteorological factors

To explore the characteristics of PM2.5 and PM10 in Chengdu, China, and their relationship with meteorological factors, monthly average concentrations of PM2.5 and PM10 in Chengdu from 2015 to 2018 were collected, and their relationships with meteorological factors were analyzed by using Pearson correlation analysis method. The results show that: (1) Pue to the implementation of a series of air pollution control measures since 2015, the average annual concentration of PM2.5, PM10 in Chengdu shows a slowly decreasing trend year by year. And the seasonal PM2.5, PM10 concentration in Chengdu from 2015 to 2018 decreased in the order of winter, spring, autumn and summer. (2) Different meteorological factors have different effects on the monthly average concentration of PM2.5 and PM10 in Chengdu. The concentrations of PM2.5 and PM10 show a high negative linear correlation with temperature and precipitation, which indicates that temperature and precipitation are two key factors affecting the monthly average concentrations of PM2.5 and PM10 in Chengdu. Sunshine duration, monthly average wind speed and relative humidity are also negatively correlated with PM2.5 and PM10 monthly average concentrations. However, compared with precipitation and temperature, the linear correlation between sunshine duration, monthly average wind speed and PM2.5, PM10 is lower, while the linear correlation between relative humidity and PM2.5, PM10 is even weaker, and less significant, indicating that the change of relative humidity has little effect on the accumulation and diffusion of PM2.5 and PM10 in Chengdu.