The difference between fog and smoke

The difference between fog and smoke: visibility, relative humidity, thickness, boundary characteristics, color and diurnal variation.

1. Visibility: The horizontal visibility of fog is usually less than 1 km, while that of haze can be less than 10 km.

2. Relative humidity: The relative humidity of fog is usually greater than 90%, while that of haze is less than 80%.

3. Thickness: The thickness of fog is usually about tens of meters to 200 meters, while the thickness of haze can reach about 1-3 kilometers.

4. Boundary characteristics: The boundary characteristics of fog are clear, and it may be clear in Wan Li after passing through the fog area. However, there is no clear boundary between haze and clear sky.

5. Color: The color of fog is usually milky white and bluish white, while the color of haze can be yellow or orange gray.

6. Diurnal variation: Fog generally appears from midnight to early morning, and the diurnal variation characteristics of haze are not obvious. If the air mass does not change greatly and the air mass is stable, it will last for a long time.

Turbid component

Haze is composed of particles such as dust, sulfuric acid, nitric acid and organic hydrocarbons in the air. It will also make the atmosphere turbid, blur the vision and worsen the visibility. If the horizontal visibility is less than 65,438+00,000 meters, the sight distance obstacle caused by this non-aqueous aerosol system is called haze or dust haze, and the Hong Kong Observatory calls it haze.

Haze is mainly composed of sulfur dioxide, nitrogen oxides and inhalable particles. The first two are gaseous pollutants, and the last particulate matter is the main reason for aggravating smog weather pollution. Together with the fog, they make the sky gloomy in an instant. The abbreviation of particulate matter is PM, and Beijing monitors fine particulate matter (PM2.5), that is, pollutant particles with aerodynamic equivalent diameter less than or equal to 2.5 microns.