成都平原经济区城市空气质量时空变化特征

Study on Spatial-temporal Variation Characteristics of Urban Air Quality in Chengdu Plain Economic Zone

基于2016—2020年成都平原经济区城市空气质量监测数据,应用空气质量综合指数评价法、Pearson相关分析法,对成都平原经济区空气质量时空变化特征、成都市主要污染物变化特征进行了研究.结果表明:1)2016—2020年,成都平原经济区城市群中空气质量指数出现了2个高值和2个低值中心,高值中心分别位于成都市、德阳市,2个低值中心分别位于雅安市、遂宁市,即成都市和德阳市空气质量最差,雅安市和遂宁市的空气质量最优;对于不同季节,1—12月,成都平原经济区的空气质量综合指数呈U字型变化,即空气质量6—10月较好,11月—次年2月较差.2)2016—2020年,成都市PM_(2.5)质量浓度值皆超过了国家二级标准限值,并且以PM_(2.5)为首要污染物出现频率最高,而O_(3)、CO、SO_(2)年均质量浓度在研究时段内均低于国家二级标准质量浓度限值.3)2016—2020年,成都市PM_(2.5)质量浓度与能见度呈显著负相关;年尺度上,成都市PM_(2.5)质量浓度与平均气温呈低度负相关,与风速、降水量呈弱负相关;季尺度上,除气温在春、夏、冬季节与PM_(2.5)质量浓度呈弱正相关外,4个季节中PM_(2.5)质量浓度与风速、降水量皆呈弱负相关.4)影响成都市PM_(2.5)质量浓度的社会经济因子主要是汽车尾气、工业烟(粉)尘排放.PM_(2.5)与地区生产总值、工业增加值、机动车保有量呈高度负相关,与工业烟(粉)尘排放量呈高度正相关.

Based on the urban air quality monitoring data of Chengdu Plain Economic Zone from 2016 to 2020,this paper applied the air quality comprehensive index evaluation method and Pearson correlation analysis method to study the characteristics of spatial and temporal changes of air quality in Chengdu Plain Economic Zone and the characteristics of changes of major pollutants in Chengdu city.The results show that:1)From 2016 to 2020,there were two high-value and two low-value centers in the air quality index in the urban agglomeration of the Chengdu Plain Economic Zone.The high-value centers were located in Chengdu and Deyang,and the two low-value centers were located in Ya’an and Suining.The air quality is the worst in Chengdu and Deyang,and the air quality in Ya’an and Suining is the best;for different seasons,from January to December,the comprehensive air quality index of the Chengdu Plain Economic Zone changes in a U-shape,that is,the air quality is better in June-October,and poor in November-February of the next year.2)From 2016 to 2020,the concentration of PM_(2.5)in Chengdu exceeded the national secondary standard limit,and during the period studied,the frequency of PM_(2.5)as the primary pollutant in Chengdu was the highest,while the annual average concentrations of O_(3),CO,and SO_(2)were at the period studied below the standard(below the national secondary standard concentration limit).3)From 2016 to 2020,the PM_(2.5)concentration in Chengdu was significantly negatively correlated with visibility.On the year scale,the PM_(2.5)concentration in Chengdu was negatively correlated with temperature in a low degree,and weakly negatively correlated with wind speed,and precipitation.On the seasonal scale,the PM_(2.5)was weakly positively correlated with temperature.In spring,summer,autumn and winter,the PM_(2.5)was weakly negatively correlated with speed and precipitation.4)From 2016 to 2020,the socio-economic factors affecting the concentration of PM_(2.5)in Chengdu are mainly automobile exhaust and exhaust gases from factories.PM_(2.5)concentration was highly negatively correlated with vehicle ownership,industrial added value and regional GDP,and highly positively correlated with industrial smoke(dust)emissions.