郑州市大气污染特征及其与气象条件的关系

Air pollution characteristics in Zhengzhou City and their relationship with meteorological factors

利用2001-2012年郑州市空气质量日报资料及2013-2015年郑州市大气污染逐时监测资料,分析了郑州市大气污染特征.结合同期气象观测资料,分析了郑州市大气污染与地面气象要素、最大混合层厚度和稳定能量等气象参数之间的关系,重点分析了2014-2015年冬季采暖期郑州市发生重污染天气(AQI≥200)的气象条件,结果表明,2013年后,郑州市大气优良天数减少,大气污染加重,PM_(2.5)成为主要污染物.郑州市大气污染程度与风速整体呈负相关,与相对湿度冬季呈正相关,夏季呈负相关,最大混合层厚度和稳定能量是表征郑州市大气污染气象条件(特别是冬季)的重要参数.郑州市重污染天气多发生在冬季采暖期,处于地面均压场控制下,高空以平直纬向气流为主,连续多日出现最大混合层厚度低、低空稳定能量大、高湿小风的气象条件时,容易发生重污染天气.

Daily air quality from 2001 to 2012 and hourly monitoring data from 2013 to 2015 were used to analyze the characteristics of air pollution in Zhengzhou City. Also the relationship between air pollu- tion and surface meteorological factors, maximum mixing depths （MMD）, and stable energy was dis- cussed by using the meteorological data from the same period. Analysis of the meteorological factors was made when heavy pollution episodes （AQI≥200） occurred in Zhengzhou City during heating period. The results showed that after 2013 air pollution became worse with decreasing days of excellent and good air quality in Zhengzhou City and PM2.5 became the main pollutant. The air quality had negative correlation with wind speed, a positive correlation with humidity in winter and a negative correlation with humidity in summer. MMD and stable energy were also important parameters reflecting the influence of meteorologi- cal conditions on air pollution, especially in winter. Heavy pollution episodes in Zhengzhou City mostlyoccurred during the heating period. When homogeneous surface pressure field and upper zonal circula- tion with fiat and straight flow became dominated, heavy pollution episodes were likely to take place, with a low MMD, high stable energy, light wind and high humidity persisting for several days.