衡水市空气污染特征与气象条件分析

Analysis of Air Pollution Characteristics and Weather Conditions in Hengshui City

利用2005-2006年衡水3个环境监测点的逐日逐时监测资料对衡水市的空气质量进行了分析。结果表明，衡水市可吸入颗粒物（PM10）为首要污染物的天数基本在300d以上；二氧化硫（SO2）为主要污染物的天数为40～88d。在观测时段内未出现二氧化氮（NO2）为首要污染物的情况。衡水空气质量多为良，二级以上天数在300d以上。污染物浓度白天段要高于夜间段。污染物浓度具有明显的季节变化，冬半年到夏半年污染物浓度逐渐降低，从夏半年到冬半年污染物浓度逐渐升高。大雾及冬季燃煤取暖对空气污染具有正贡献；降水对降低空气中PM10的浓度有积极的作用，大的降水后空气质量维持优的时间较长，反之，空气质量达到优的持续时间较短。空气温度以及低层的空气湿度对污染物浓度有很大的影响。

The air quality in Hengshui City was analyzed, using the monitoring data generated in real time in three environmental monitoring sites from 2005 to 2006. It was found that among three pollutants monitored, the pollution days with PM10 as major pollutant were 275, while the pollution days with the other two as major pollutants were above 300. The pollution days with SO2 as major pollutant were between 40 and 88 and no pollution days with NO2 as major pollutant were observed within the given period. The air quality in Hengshui City was good for the most part and Level- Ⅱ days were above 300. The pollution density was higher at night than in the daytime. It also changed with seasons and decreased gradually from the winter-half year to the summer-half year, and increased otherwise. Fog and coal heating in winter contribute to air pollution and the precipitation could bring down the density of PM10 in the air. The air quality could remain good for a longer time after a heavier precipitation. The air temperature and humidity in lower atmosphere both exerted a significant impact on pollutant density.