摘要
近年来我国空气质量持续改善,大气颗粒物浓度明显降低.为探究气象条件和减排措施对细颗粒物(PM_(2.5))浓度的相对贡献,选取两个典型代表城市——北京和成都,对比分析两城市所处的地理环境条件、污染排放以及气象扩散条件.结果表明,北京与成都2013~2018年重污染天数及污染过程显著减少,SO_(2)和PM_(2.5)浓度降幅明显,与2013年相比,两城市2018年SO_(2)浓度的降幅分别为77.8%和70.9%,PM_(2.5)浓度分别降低了42.7%和48.5%.冬季PM_(2.5)浓度下降速率最大,每年分别以13.5μg·m^(-3)和14.1μg·m^(-3)的速率降低.2013~2018年成都较北京风速偏小,温度偏高约3℃,静小风日数偏多,冬季静小风频率高,混合层高度、大气容量指数以及通风系数明显偏小,大气扩散条件较差.综合静稳天气指数(SWI)和环境气象指数(EMI)结果表明北京大气扩散条件优于成都,但近几年的变化程度有所不同.2014~2018年两城市的EMI呈减小趋势,2018年成都地区EMI降幅最显著,气象条件明显好转.与2014年相比,2018年北京与成都全年大气污染减排对PM_(2.5)浓度的贡献分别为33.5%和24.0%,气象条件的贡献分别为7.2%和11.1%;冬季减排贡献分别为31.7%和32.5%,气象条件的贡献比全年的大.
In recent years,China’s air quality has been improving,and the concentration of atmospheric particulate matter has decreased significantly.In this study,the pollution characteristics and trends of two typical representative cities(Beijing and Chengdu) were analyzed.The geographical locations,pollution emissions,and meteorological diffusion conditions of the two cities were compared,to evaluate the relative contribution of meteorological conditions and pollution reduction regulations in decreasing fine particulate matter(PM_(2.5)) concentrations.The results showed that the number of heavily polluted days and pollution episodes in Beijing and Chengdu decreased significantly from 2013 to 2018,and the concentration of SO_(2) and PM_(2.5) decreased substantially.Compared to 2013,SO_(2) concentration in Beijing and Chengdu has decreased by 77.8% and 70.9%,whereas PM_(2.5) concentration has decreased by 42.7% and 48.5%,respectively.The largest reduction appeared in winter,when PM_(2.5) decreased at an annual rate of13.5 μg·m^(-3) for Beijing and 14.1 μg·m^(-3) for Chengdu.During the study period,the wind speed in Chengdu was less than that in Beijing,temperature was approximately 3℃ higher,and static wind in winter was more frequent.A significantly lower mixed-layer height,atmospheric capacity index, and ventilation coefficient in Chengdu resulted in more unfavorable atmospheric diffusion conditions.The static and stable weather index and the environmental meteorological index(EMI) also showed that the atmospheric diffusion conditions were better in Beijing than in Chengdu.The EMI of the two cities showed a decreasing trend during the study period,and the decline in EMI in Chengdu was the most significant in 2018,indicating an evident improvement in meteorological conditions.In 2018,emission reductions are estimated to have contributed 33.5% and 24% to the decrease in PM_(2.5) in Beijing and Chengdu,respectively,and meteorological conditions contributed 7.2% and 11.1% to the reduction in these two cities.In wint
作者
党莹
张小玲
饶晓琴
康平
何建军
卢宁生
华明
向卫国
DANG Ying;ZHANG Xiao-ling;RAO Xiao-qin;KANG Ping;HE Jian-jun;LU Ning-sheng;HUA Ming;XIANG Wei-guo(Plateau Atmosphere and Environment Key Laboratory of Sichuan Province,School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,China;Environmental Meteorological Center of China Meteorological Administration,Beijing 100081,China;Chinese Academy of Meteorological Sciences,Beijing 100081,China;Chengdu Meteorological Bureau,Chengdu 610072,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2021年第8期3622-3632,共11页
Environmental Science
基金
国家重点研发计划项目(2016YFA0602004,2018YFC0214002)
四川省科技计划项目(2018JY0011,2018SZDZX0023)。
关键词
污染特征
变化趋势
减排贡献
静稳天气指数(SWI)
环境气象指数(EMI)
北京
成都
pollution characteristics
trend of change
contribution to PM2.5decrease
stable weather index(SWI)
environmental meteorological index(EMI)
Beijing
Chengdu
