典型城市室外PM_(2.5)污染时空分布及演变特征

Spatial-temporal distribution and evolution characteristics of outdoor PM_(2.5) pollution in typical cities

基于国家监测的室外PM_(2.5)质量浓度大数据,对全国室外PM_(2.5)污染时空分布及典型城市室外PM_(2.5)污染演变趋势进行研究。结果显示,2019年我国室外PM_(2.5)污染分布具有显著的区域性和季节性特征,全国地级及以上城市室外PM_(2.5)污染具有较强的全局空间自相关性,华北地区、西南地区、新疆西部等地域大部分城市具有明显的局部空间自相关性。其中,京津冀及周边城市、长江中下游平原、汾渭平原、新疆的和田地区和喀什地区等污染较为严重。哈尔滨、北京、上海、广州和重庆5个典型城市室外PM_(2.5)年平均质量浓度呈下降趋势,室外PM_(2.5)3年滑动平均浓度不断降低,Spearman秩相关系数为负值且绝对值均大于0.829。

The spatial-temporal distribution and the evolution trend of outdoor PM_(2.5) pollution in typical cities in China are investigated based on the PM_(2.5) mass concentrations from the National monitoring data.The results show that in 2019,the outdoor PM_(2.5) pollution distribution has distinctive regional and seasonal characteristics.For the prefecture level and above cities,the outdoor PM_(2.5) pollution distribution has a strong global spatial autocorrelation,while most of the cities in northern China,southwestern China and western Xinjiang indicate a strong local spatial autocorrelation.The serious pollution appeares in the places like Beijing,Tianjin,Hebei and their surrounding cities,middle-lower Yangtze Plain,Fenwei Plain,Hotan and Kashi prefecture in Xinjiang Province,etc..The annual mean mass concentration of outdoor PM_(2.5) in 5 typical cities of Harbin,Beijing,Shanghai,Guangzhou and Chongqing shows a downward trend.The three-year moving mean concentration of outdoor PM_(2.5) continues to decrease.The Spearman's rank correlation coefficient is negative and the absolute value is greater than 0.829.