In the first quarter of 215, the haze weather was 4 days, and the air quality was generally 1 days.

smog is a combination of fog and haze. Haze is common in cities. Many areas in China combine fog with haze as a disastrous weather phenomenon for early warning and forecasting, which is 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 amount of fine particulate matter (PM 2.5). Once the emission exceeds the atmospheric circulation capacity and carrying capacity, the concentration of fine particulate matter will continue to accumulate. At this time, if it is affected by calm weather, it is easy to appear a wide range of smog.

in p>213, "smog" became the key word of the year. In January of this year, four smog processes enveloped 3 provinces (autonomous regions and municipalities). In Beijing, only five days were not haze days. It is reported that less than 1% of the 5 largest cities in China meet the air quality standards recommended by the World Health Organization. At the same time, seven of the 1 most polluted cities in the world are in China.