北京气态污染物变化与空中水汽变化的比较研究

Comparison between the Change of Gaseous Pollutants and Precipitable Water Vapor in Beijing

气态污染物(SO2、NO2、CO)是形成PM2.5的主要来源。水汽是影响天气变化的关键要素,也是导致霾灾害天气发生的关键因子。水汽的变化是否影响空气中气态污染物的质量浓度变化?该文通过北京2013年地面气态污染物和无线电探空水汽的比较,发现:秋冬春季节PWV变化与SO2、NO2、CO变化呈显著正相关(相关性>0.5),与O3变化呈负相关;这一相关性在降水较多的夏季并不明显。秋冬春季节无线电探空分层水汽与气态污染物变化的比较中,第3、4、5层水汽变化与气态污染物变化的相关性最佳,由此推断:空中水汽层在较为湿润的时候是地表气态污染物(SO2、NO2、CO)无法向上扩散;而O3与大气层水汽相互融合,因而呈现负相关特性。根据这一推断可知:在少雨的秋冬春季节,当空中水汽层较为湿润,地表气态污染物(SO2、NO2、CO)无法向上扩散,因而形成地表霾天气。

Gaseous pollutants such as SO2, NO2 and CO are the main sources to form PM2.5. Precipitable water vapor is the key elements that result in the change of the weather which is also one of the key factors of the haze weather. Whether the change of precipitable water vapor affects the change of gaseous pollutants concentration？ By analyzing the observations of gaseous pollutants and Radiosonde Precipitable Water Vapor （PWV） of Beijing in 2013, it was found that obvious positive correlation existed between radiosonde PWV and gaseous pollutants （SO2, NO2, CO） changes, and negative positive correlation existed between radiosonde PWV and O3 during autumn, winter and spring, except summer. For the multilayered radiosonde PWV and PM2.5/PM10 observations, the positive or negative correlation is especially obvious in the 3th, 4th and 5th layer of PWV changes. The correlation indicates that SO2, NO2, CO can＇t pass the tropospheric layer while plenty of PWV exist in the tropospheric layer. Therefore, it can infer that since the tropospheric layer is relatively moist during the rainless seasons, e.g. autumn, winter and spring, SO2, NO2, CO cannot spread upward, thereby form the surface haze weather.