Haze is a mixture of fog and haze. When the humidity is high in the morning and evening, there are many components of fog. When the daytime humidity is low, haze is the main force, and the relative humidity is between 80% and 90%. Among them, fog is a natural weather phenomenon, and the water vapor in the air is relatively dense. Although dust is the condensation core, it is generally non-toxic and harmless; The core substances of smog are substances suspended in the air such as smoke and dust. The relative humidity of the air is below 80% and the color is yellow. Gas can directly enter and attach to human lower respiratory tract and lung lobes, which is harmful to human health. The formation of haze weather is mainly man-made environmental pollution, and natural conditions such as low temperature and little wind make it difficult for pollutants to spread.

On 20 14, 1314, the state reported the haze weather as a natural disaster for the first time.