霾,这个曾经生僻的汉字,近年来已变得尽人皆知。它蔓延南北,飘荡东西,有时候甚至覆盖上百万平方公里的国土,搞得昏天黑地,亿万民众苦不堪言。中国各级政府所属气象部门向民众报告PM2.5浓度,所用的是汉语“雾霾”一词。雾是常见气象,即接近地面的水蒸气遇冷凝结后飘浮在空气中的小水滴,一般遇到阳光便逐渐消失。但霾就不同了,它在北京等大城市竟可遮天蔽日,弥漫好几天,甚至逾一周。难怪市民 Haze, this once rare Chinese character, has become well-known in recent years. It spread north and south, floating things, and sometimes even cover millions of square kilometers of territory, fainted, hundreds of millions of people miserable. Meteorological departments at all levels of government in China report PM2.5 concentrations to the public using the Chinese word “smog”. Fog is a common weather, that is, close to the ground water vapor condensate floating in the air after the small drops of water, the general encounter the sun will gradually disappear. But the haze is different, it can actually cover the sun in the big cities such as Beijing, diffuse a few days, even more than a week. No wonder the public