中国空气污染指数变化特征及影响因素分析

Variation Characteristics and Influencing Factors of Air Pollution Index in China

以2001～2010年我国42个城市逐日空气污染指数、主要污染因子、空气质量级别和空气质量状况资料为基础,分析了近10 a我国空气质量的变化特征.结果表明,我国城市大气受燃煤影响较为严重,可吸入颗粒物为主要污染因子,空气质量状况以优、良和轻微污染居多;空气质量季节变化明显,冬季空气污染最严重,夏季最轻;从年际变化看,空气质量表现出逐年好转趋势;城市大气环境质量在区域上存在显著差异,表现为由南到北、从沿海到内陆逐渐变差的趋势.对空气污染影响因素的分析表明,局地污染和西北地区沙尘传输造成的自然降尘是我国城市空气质量的主要污染源;气象要素对大气污染物有制约关系,空气污染指数与降水量、风速、逆温线性相关;地形的空间差异影响着气象条件的分布,进而对空气质量的空间变化产生影响;人类活动对城市空气质量也存在一定的影响,且具有双重作用.

Based on the daily air pollution index(API),primary pollutant,air quality level and status of 42 cities in China during 2001-2010,the characteristics of air quality were analyzed.The results showed that the atmosphere was significantly influenced by consumption of coal.The primary pollutant was PM10,and the air quality status was excellent(0<API<50),good(50<API<100) and slightly polluted(100<API<150) in the majority.The air pollution status varied seasonally,which was the most serious in winter,and slightest in summer.The air quality was better and better in the observed period generally;The spatial distribution of urban air environment displayed a worsening trend from the south to the north and from the coasts to the inland;The local emission and natural dust transmission from the Northwest China was the main sources of urban air pollution;The air pollutants were impacted by the meteorological elements,and the air pollution index correlated linearly with precipitation,wind speed and temperature inversion;The distribution of weather conditions,which was affected by the terrain,also could influence the air quality;In addition,the human activities had both positive and negative functions on the urban air quality.