全国31个重点城市空气质量特征分析

An analysis on the characteristics of air quality of 31 cities in China,2014

目的分析2014年全国31个重点城市空气质量特征,为预防大气污染提供依据。方法利用环境保护部数据中心每日发布的全国空气质量监测数据,对31个城市空气质量和首要污染物分布特征,及其空气质量等级与首要污染物关系进行分析。结果 31个城市年均空气质量指数(AQI)为83,空气污染最严重的区域是华北地区,最严重城市是石家庄市。全年空气质量以二级日数为主,而空气污染日数(AQI>100的日数)占全年的34.40%;首要污染物为PM2.5和PM10,分别占总日数的38.30%和29.50%,其中合肥市最高,达全年日数的78.00%。AQI水平在1—3月最高,其次为10—12月,4—9月相对较低且平稳;AQI等级与首要污染物分布有关,空气质量AQI水平在三到六级,以PM2.5为首要污染物所占的天数,分别占三到六级各级总天数的61.00%、83.90%、96.30%及72.30%。结论全国2014年31个城市空气质量分布呈明显区域特征,且随季节改变呈明显变化。空气污染的首要污染物以PM2.5为主,PM2.5日数比例随着空气污染等级的增加而增加。

Objective To analyze the characteristics of air quality of 31 cities in 2014 and to provide scientific evidence for air pollution prevention. Methods Data were from the national air quality monitoring data daily published by the data center of the Ministry of Environmental Protection of the People ' s Republic of China. We analyzed distribution characteristics of the air quality and primary pollutants of 31 cities,as well as the relationship between air quality levels and primary pollutants. Results The average AQI of 31 cities was 83. The air quality of the north China was the worst,and the air quality Shijiazhuang was the worst. The air quality was mainly at level II in 2014,and the air pollution days that AQI was higher than 100 were accounted for 34. 4%. Primary pollutants were mainly PM2. 5and PM10,which was accounted for38. 30% and 29. 50% respectively,but that was accounted 78. 00% in Hefei. The level of AQI was higher during January to March than that of October to December. The level of AQI was relatively low and stable during April to September. The level of AQI was associated with the primary pollutant distribution. When the level of AQI was in level 3,4,5 and 6,the days of PM2. 5was accounted for 61. 00%,83. 90%,96. 30% and 72. 30% respectively. Conclusions In 2014,the air quality of 31 cities presented regional characteristics,and changed with season. The main primary pollutant was PM2. 5,and PM2. 5increased with the air pollution levels.