There is information about smog, and smog is introduced.

1, smog, is a combination of fog and haze. Smog is very common in cities. In many areas of China, fog and haze are combined as disastrous weather phenomena for early warning and forecasting, which are collectively called "haze weather". Haze is the result of interaction between specific climatic conditions and human activities. The economic and social activities of high-density population will inevitably emit a large number of fine particles (PM2.5). Once the emission exceeds the atmospheric circulation capacity and carrying capacity, the concentration of fine particles will continue to accumulate. At this time, if it is affected by calm weather, it is easy to have a wide range of smog.

In 2.20 13, "smog" became the key word of the year. In June 5438+10, four smog processes enveloped 30 provinces (autonomous regions and municipalities). In Beijing, only five days are not foggy. It is reported that less than 65,438+0% of the 500 largest cities in China meet the air quality standards recommended by the World Health Organization. Meanwhile, among the 65,438+00 most polluted cities in the world, 7 are in China. 2014,6543814, the national disaster reduction office and the Ministry of civil affairs listed the haze weather that is harmful to health as a natural disaster for the first time in 20 13 years. 20/kloc-in February, 2004, Beijing pointed out that the primary task of controlling smog pollution and improving air quality is to control PM2.5, and major measures should be taken from reducing coal burning, strictly controlling vehicles, adjusting industries, strengthening management, joint prevention and control, and managing according to law, focusing on key areas, strictly assessing indicators, strengthening environmental law enforcement and supervision, and earnestly investigating responsibilities. 20 16 12, the most persistent smog weather came in winter, and many cities have been seriously polluted. It is expected to last for another four days, and it will weaken and dissipate from north to south after 2 1 until midnight. 19 will enter the worst period of this round of smog at night, and the affected areas include Beijing-Tianjin-Hebei, Shanxi, Shaanxi, Henan and other provinces and cities 1 1. On 20 17, Premier Li Keqiang personally wrote "Resolutely Fight the Blue Sky Defence War" into the report.