北京市区春季燃烧源大气颗粒物的污染水平和影响因素

以大气中PM2.5和PM10为研究对象,于2005-03-13—25共7天的时间内,在中国地质大学(北京)测试楼顶、首钢焦化厂和首钢东门设立3个采样点进行采样监测。结果表明:PM2.5和PM10质量浓度的日变化呈现一定规律性,在不同时段PM2.5和PM10的质量浓度不尽相同,且变化较大,在特定时刻出现峰值,主要受污染源排放和气象因素的控制;PM2.5和PM10质量浓度随气温的升高而降低,这与高温有利于颗粒物扩散、低温容易形成逆温层有关;在一定的相对湿度范围内(以大气中水汽不发生重力沉降为界限),PM2.5和PM10质量浓度与相对湿度呈正相关关系;而当发生降水时,由于水滴的冲刷和附带作用,PM2.5和PM10质量浓度降低;PM2.5和PM10质量浓度与风级呈明显的负相关关系。通过北京市与国内8个省会城市的PM2.5和PM10质量浓度的对比,发现北京市PM2.5和PM10污染比较严重,PM2.5和PM10质量浓度分别超过了1996年中国制定的PM10排放标准和1997年美国EPA制定的PM2.5排放标准。

The Pollution Level and Affecting Factors of Atmospheric Particulates from Combustion during Spring in Beijing City

In order to have a grasp of the pollution situation of PM_(2.5) and PM_(10) from combustion in Beijing,the distribution regularities and influence factors of PM_(2.5) and PM_(10)were analyzed after sampling PM_(2.5) and PM_(10) at three sites representing combustion sources,i.e.the top of testing building at China University of Geosciences in Beijing(CUGB),the Shougang Coking Plant and the east gate of Shougang, from March 13 through March 25,2005.A series of results are concluded as follows.Being controlled by pollution sources and weather conditions,the concentrations of PM_(2.5) and PM_(10) vary hourly,and two peaks present at different time in a day;they vary with temperature as well,the maximum concentration has relationship with the low temperature,while the minimum can be detected at the high temperature.The concentrations of PM_(2.5) and PM_(10) from combustion vary with the content of moisture as well,the maximum value is related to the high humidity and the minimum value can be detected in the low moisture.Comparing the concentrations of PM_(2.5) and PM_(10) from combustion in Beijing with those in other 8 cities of China,it is found that the pollution level in Beijing is very serious and the concentrations all exceed the pollution standards of China for PM_(10) and U.S.EPA for PM_(2.5).It is found that the concentration of PM_(10) is still above the pollution level of China.New measures about combustion emission and environmental protection should be established as soon as possible to improve the air quality in Beijing city.