Causes of haze weather

1. Poor diffusion conditions of pollutants.

There are many high-rise buildings in the city and the ventilation corridors are blocked, which makes the particulate matter in the air accumulate in the urban area and cannot spread.

Rivers in the city lead to low ground temperature and high altitude temperature, and the vertical air flow is limited, forming an inversion layer of "upper heat and lower cold", and the particles in the air are pressed at a low altitude, making it difficult to spread upward.

2. High emission intensity of pollutants.

Pollution emissions mainly include industry, coal burning, motor vehicles, dust and so on. For example, the demand for automobiles increases, the exhaust emissions inevitably increase, the emissions from industrial production, the dust from construction sites, the burning of garbage and so on.

3. Regional communication impact

In a transmission channel, such as Beijing-Tianjin-Hebei and the surrounding "2+26" cities, the average mutual influence is 20%-30%, which will increase to 35%-50% when there is heavy pollution weather, and some cities may reach 60%-70%, and the mutual influence is obvious.