2013年夏季北京市一次空气重污染过程分析

Analysis about the Characteristics and Formation Mechanism of a Serious Pollution Event during Summer in 2013 in Beijing

结合WRF数值模式与气象、污染物观测资料,综合分析了北京市2013年6月29日-7月2日夏季一次空气重污染过程的特征、气象条件及成因。结果表明:重污染过程期间6月30日-7月1日细颗粒物平均浓度为184μg/m^3,平均风速为2.07 m/s,平均相对湿度为87.25%;24 h变温基本在-0.83~3.81℃之间,24 h平均变压在-3.59^-0.18 h Pa之间;北京及周边地区不利的气象条件是重污染形成的主要原因,局地累积及本地化学反应、周边地区秸秆焚烧输送又加剧了此次空气重污染的程度,形成了此次夏季罕见的重污染过程。

Atmospheric environmental background,weather conditions and formation mechanism of a typical air pollution episode from June 29 th to July 2nd,2013 in Beijing were investigated by combining observed data and the numerical model.Results showed that the air pollution in June 30 th-July 1st episode was most serious with daily average PM2.5concentration of 184 μg/m^3 and the ground meteorological elements characterized mainly as small wind（2.07 m/s）,large humidity（87.25%）,small temperature（-0.83-3.81 ℃） and pressure（-3.59--0.18 h Pa） transformer. This serious pollution process was caused by two main reasons：unfavorable atmospheric circulation and weather conditions surrounding Beijing was the main reason for the formation of heavy pollution;local accumulation,chemical reaction and the transportation of pollutants by burning straw aggravated the degree of heavy air pollution that was rare in summer.