四川盆地城市群6种大气污染物的时空分布

Temporal and spatial distribution of six kinds air pollutants in cities in the Sichuan Basin

利用四川盆地18个城市2015-2016年6种大气污染物质量浓度资料,采用了集中期、集中度和变异系数等统计学方法,对该地区大气污染的时空分布特征进行了分析,将四川盆地划分为3个区进行对比研究.结果表明,四川盆地18个城市中,大气污染最严重的是自贡市,年均空气质量指数为100,污染天数占总天数的37.6%;污染最轻的是广元市,年均空气质量指数为57,污染天数占总天数的4.5%.四川盆地3个区域按照污染物质量浓度高低以及出现污染天数的长短排序均为:川南经济区>成都平原经济区>川东北经济区.研究时间段内,18个城市PM2.5年均质量浓度达标的只有广元市;PM10年均质量浓度达标的只有广元市和巴中市;SO2年均质量浓度18个城市均达标;NO2年均质量浓度除成都市和重庆市外,其他16个城市均达标;所有城市的CO和O3日质量浓度均达标.近36年来,颗粒物和SO2质量浓度呈现不同程度降低,表明国家对大气污染物排放的管控措施对颗粒物和SO2污染改善明显.污染物PM2.5、PM10、CO、NO2和SO2质量浓度的季节变化为冬季高,夏季低;O3质量浓度季节变化则为冬季低,夏季高.PM2.5、PM10和O3质量浓度高的时段相对于SO2、NO2和CO来说更为集中,PM2.5、PM10、SO2、NO2和CO高质量浓度时段主要集中在1月左右,O3高质量浓度时段主要集中在6月左右.不同城市间SO2和NO2质量浓度差异明显,其他污染物质量浓度分布则较为均匀.

The paper has analyzed the characteristics of temporal and spatial distribution of pollutants in there of by using statistical methods such as concentration period,concentration degree and coefficient of variation,to study the concentration data of six air pollutants in 18 cities from 2015 to 2016,and the Sichuan Basin has been divided into three economic areas for a comparative study.The results show that for the 18 cities in the Sichuan Basin,Zigong was the most polluted with an annual average air guality index was 100 and the polluted days amounting to about 37.6%of the total days;the lightest polluted city was Guangyuan,whose annual average air guality index was 57,and the polluted days were 4.5%of the total days.The three areas of the Sichuan Basin were ranked according to the concentration of pollutants and the number of days of pollution:South Economic Zone>Chengdu Plain Economic Zone>Northeast Economic Zone.In the view of pollutants’annual average concentration for the 18 cities between 2015 and2016,only Guangyuan reached the national ambient air quality standards for PM25,and Guangyuan and Bazhong reached the standard for PM10.For SO2,all of the cities reached the standard,but for the pollutant NO2 only Chengdu and Chongqing didn’t reach the standard.For the daily concentration of pollutants CO and O3,all of the 18 cities reached the standard.In the past 36 years,the concentrations of particulate matter and SO2,have been reduced to some extent,indicating that the control of air pollution stipulated in the national policy had obvious improvement.The four pollutants,PM2.5,PM10,CO and NO2,showed obvious seasonal variations,and the winter concentration was higher than summer,while the concentration of O3,on the contrary,showed a lower winter concentration and a higher summer concentration.In terms of the concentration degree,the pollutants PM2.5,PM10 and O3,were much more concentrated than SO2,NO2 and CO,and for the concentration period,the pollutants PM2.5,PM10,SO2,NO2 and CO were mainly concentrated in January,while O3,mainly concentrated in June.In different cities,the concentration distribution difference of SO2 and NO2 was obvious,but that of other pollutants was more uniform.