2013年1月北京市一次空气重污染成因分析

Formation Mechanism of a Serious Pollution Event in January 2013 in Beijing

采用数值模式与观测资料相结合的方式，对北京市2013年1月9日至15日一次空气重污染过程的大气环境背景、气象条件和形成原因进行了初步分析．结果表明，重污染过程期间10日至14日PM2.5平均值为323μg·m^-3；重污染过程与当地气象条件密切相关，稳定的大气环流形势为污染的持续提供了大气环流背景，风速较小、湿度较大、边界层较低、持续逆温是造成重污染的主要原因；重污染过程中区域输送对北京PM2.5贡献率在53％～69％之间且存在明显的二次转化，区域输送起着更为重要的作用；气象条件对持续性重污染的形成和破坏起到了关键性的作用，因此需要加强对重污染预警预报研究，以有效预防和控制空气重污染．

The weather conditions, atmospheric environmental background and formation mechanism of a heavy air pollution episode in Beijing City from January 9th to 15th, 2013 was preliminarily investigated by combining observed data and the WRF meteorology model. The results showed that the average concentration of PM2.5 was 323 μg·m^-3 from January lOth to 14th; the heavy pollution episode was closely related to the local meteorological conditions; the stable atmospheric circulation pattern provided favorable environmental field for the lasting of this heavy air pollution; small wind speed, high humidity, low PBL, and lasting temperature inversion were the main reasons for this heavy air pollution incident ; further analysis showed that contributions of regional transmission to the receptor sites in Beijing were between 53% -69% and there were obvious secondary conversions and transformations; overall regional transportation played a more important role during this serious air pollution incident; the meteorological conditions played a key role in the formation and destruction of the heavy air pollution, therefore we need to strengthen the study on early warning of heavy air pollution, in order to prevent and control the air heavy pollution effectively.