What is the smog in Beijing? When did it start?

According to statistics, it existed 50 years ago. The visibility in the air was 30 kilometers at that time. Ten years ago, it seemed to be 10 km. Now it's serious. It is estimated that the road environment in China is too bloated, which is related to driving too much. It was not very serious before, but it was only in recent years that the concept of fog was defined.

When did the smog start?

The starting time varies from place to place, and the most impressive ones should be the 2008 Beijing Olympic Games and the 2009 Shanghai World Expo, so the smog was already very serious before that.

What is smog?

Haze is also called atmospheric brown cloud. In the ground meteorological observation standard of China Meteorological Bureau, haze weather is defined as: "A large number of extremely fine dry dust particles float in the air evenly, which makes the air with horizontal visibility less than 10 km generally turbid, making bright objects in the distance slightly yellow and red, and making darker objects slightly blue." According to the research, there are four areas in China where there are severe haze weather: Huanghuaihai area, Yangtze River basin, Sichuan basin and Pearl River Delta.

What's the difference between haze and fog?

Generally speaking, the difference between fog and haze mainly lies in the size of water content: fog with water content above 90% and haze with water content below 80%. Between 80% and 90%, it is a mixture of fog and haze. There are some "differences" between haze and fog: the color of fog is milky white and bluish white, while haze is yellow and orange gray; The boundary of fog is very clear, and it may be clear in Wan Li after passing through the "fog area", but the boundary between fog and surrounding environment is not obvious, and urbanization and industrialization are the main factors causing fog.

Meteorologists analyzed the distribution of smog in Beijing, and obtained the basic climatic characteristics of smog weather, such as days, interannual changes and rose changes. The distribution of smog in Beijing is blocked by terrain. In the piedmont area surrounded by mountains on three sides, the probability of smog is relatively high. Last year, there were 34 days of haze in Beijing Observatory. When there is foggy weather, the sky is gray and the visibility is not high. Haze is related to urban air pollution. In severe cases, it will have a certain impact on people's production, life and health. The Beijing Meteorological Observatory released the smog weather forecast service to the public from February 1, adding a new service to the daily weather forecast service in the capital. The smog weather forecast in Beijing is divided into three levels: (mild) smog, moderate smog and severe smog.

1. Mild haze: air relative humidity is less than or equal to 80%, visibility is more than 5km and less than10km; Second, moderate haze: the relative humidity of the air is less than or equal to 80%, and the visibility is more than 2 kilometers and less than or equal to 5 kilometers; Three: severe smog: the relative humidity of the air is less than or equal to 80%, and the visibility is less than or equal to 2 kilometers. Go out and take protection. Puweixin Tiantong imported from the United States