摘要
对2013年1月10—14日发生的持续性PM2.5重污染过程从污染过程演变、气象条件影响、与气态污染物关系、区域污染背景、PM2.5浓度空间分布演变及其与地面风场的关系、PM2.5组分特征等多个方面进行全面的分析,较为完整地还原了该次重污染案例的形成原因以及主要影响因素。主要结论包括:该次重污染过程是稳定气象条件下导致的局地污染物积累,再叠加华北区域性污染的影响共同造成,其中10、12日北京地区PM2.5浓度的快速增长反映了周边污染传输的显著影响;逆温不但造成污染物难以扩散,且不同的逆温类型对PM2.5浓度水平有显著影响,同时还发现逆温的破坏导致近地面高浓度污染物向上扩散,造成百花山出现峰值高污染浓度现象;NO2与PM2.5浓度水平的高相关性反映交通污染二次转化对PM2.5浓度水平的影响,在较高湿度条件下,SO2浓度水平对湿度敏感且表现为负相关性;该次污染过程中OM、SO2-4、NO-3、NH+4等组分在PM2.5质量浓度中的占比超过70%,说明燃煤、机动车等仍是北京地区最主要的污染来源,同时SO2-4占比最高也说明区域污染传输对该次重污染的显著贡献。
This essay delivered a comprehensive analyses on the continuance heavy pollution episode of PM2.5 from January 10-14, 2013, in terms of evolution of Pollution process, influence of metrological conditions, relations with gaseous pollutants, regional background pollution, changes of spatial distribution of PM2.5 concentration and the relations with wind field on the ground, chemical component characteristics of PM2.5 , which completely restores the causes of formation of the heavy pollution episode and key affecting elements. The major results were as follows： This heavy pollution episode was formed by the accumulation of pollutants caused by stable metrological conditions, combined with regional pollution of North China Area. Particularly, the rapid growth of PM2.5 concentration in Beijing in January 10 and 12 reflect the significant contribution of transboundary transport of pollutants. Temperature inversion leaded to unfavorable dispersion of pollutants, and different inversion patterns have significant influence on PM2.5 concentration. It was also verified that when the temperature inversion disappeared, the pollutants with high concentration level of ground layer diffused upward, which caused peak concentration level on Bai Hua mountain. High correlation between concentrations of NO2 and PM2.s showed that the secondary traffic pollution has influence on PM2s concentration. With higher humidity, SO2 concentration was sensitive to humidity and they had a negative correlation. Components of OM,SO24- ,NO3- and NH4＋ of PM2.5 account for 70% of total mass concentration, which means that coal and vehicles were still major pollution sources in Beijing. Further, the highest proportion of SOl- demonstrated that regional pollution transport was the vital contribution to this heavy pollution episode.
出处
《中国环境监测》
CAS
CSCD
北大核心
2014年第6期1-12,共12页
Environmental Monitoring in China
关键词
PM2.5
重污染
气象影响
污染传输
组分分析
PM2. 5
heavy pollution
meteorological influence
pollution transmission
component analysis
