事件:雾霾笼罩下的中国都市

Since the beginning of the spring in 2012， a number of cities in China have experienced air quality deterioration. Fogs and hazes caused by PM2.5 particulates arouse widespread concern. The China Meteorological Administration recently released "2012 China Climate Bulletin”. It shows that in 2011， the average number of haze days in the east of 100 ° E in China is 16， 7.2 days more than in normal years， which is ranked No. 4 since 1961. Frequent fogs and hazes have become one of China’s major meteorological disasters and extreme weather and climate events in 2012. The intrusion of fogs affected residents’ travel and transportation in many areas.

Meteorological data shows haze enveloped a vast land area， including the Northeast Plain， the North China Plain， the Yangtze River Basin and Sichuan Basin. Visibility in Hebei， Tianjin， Henan， Shandong， Anhui， Zhejiang， Hubei， Sichuan and other parts is less than 1，000 meters because of fog and less than 200 meters in some areas.

The sulfur content is the iconic indicator of fuel and also the important part of the formation of haze. Sulfide generation is mostly from industrial pollution and from cement， steel， coking， thermal power plants， chemical manufacturing and non-ferrous metal smelting which are all high energy consumption and high pollution enterprises. These industries accounted for more than 85% of the total emissions of sulfur dioxide. This decides that the haze "heavily polluted" areas are almost all the large and medium-sized cities， and almost completely coincide with China's heavy industry and distribution map. In addition， as a large amount of emission from vehicle in the city is also an important source of pollution and it coupled with the "heat island" effect brought by the high population density， the outbreak of the haze occurred. The frequent fogs and hazes have a great impact on transportation and triggered the accidents which caused many casualties.

自2012年入春以来，全国多个城市发生空气质量恶化，PM2.5造成的雾霾天气引起广泛关注。中国气象局最新的《2012年中国气候公报》显示，2012年，我国100°E以东地区的平均雾霾日数为16天，较常年偏多7.2天，为1961年以来第4多。雾霾天气频发，已经成为我国2012年主要气象灾害和极端天气气候事件之一，受大雾侵扰，不少地区居民出行以及交通运输受到影响。

气象资料显示被雾霾笼罩的国土面积广阔，包括东北平原、华北平原、长江中下游平原以及四川盆地等，其中，河北、天津、河南、山东、安徽、浙江、湖北、四川等部分地区有能见度不足1，000米的雾，局地能见度不足200米。

硫含量是燃油的标志性指标，也是形成雾霾的重要组成部分。而硫化物的产生很大部分来自工业污染，源于水泥、钢铁、焦化、火电厂、化工制造和有色金属冶炼等高耗能高污染企业，这些行业占二氧化硫总排放的85%以上。这次使得雾霾“重度污染”地区几乎都集中在了大中型城市，与中国重工业分布地图几乎完全重合。而此外，城市中大量汽车尾气的排放也是重要污染源，再加上人口密度过高带来的“热岛效应”，种种因素都催促着雾霾的爆发。频繁的雾、霾天气对交通运输产生了较大影响，并引发多起交通事故，造成人员伤亡。