The fog in the morning may also be haze. How to distinguish fog from haze?

Many people confuse fog with haze. As long as the weather gets worse, they think it's smog. Actually, fog and haze are two different things. Haze is the most serious weather in the north, because with the increase of coal consumption after winter, there will be a lot of absorbable particles in the air, which is easy to produce smog. And fog is composed of water vapor, which is completely different.

Ten differences between fog and haze

Morphological difference

Fog: Fog is small water droplets suspended in the air.

Smog: Smog is a small solid particle suspended in the air, which is composed of dust, sulfuric acid, nitric acid and other compounds.

chromatism

Fog: Fog is made up of small water droplets. Because of its physical characteristics, the scattered light has little to do with the wavelength, so the fog is milky white, bluish white or pure white.

Haze: Haze consists of many compounds. Due to its physical characteristics, the longer the scattering wavelength, the more the light ratio, so the smog is yellow and orange-gray.

Thickness difference

Fog: The thickness is generally tens of meters to 200 meters. This is because the mass of water droplets is large, and clouds will be close to the ground under the action of gravity.

Haze: the thickness is generally 1 km -3 km. Because the smog particles are light in weight and evenly distributed.

Humidity difference

Fog: Air suspended matter with relative humidity (water content) above 90%. When fog appears, the air is moist.

Haze: air suspended matter with relative humidity (water content) lower than 80%, and the air is relatively dry when haze occurs.

The relative humidity between 80% and 90% is a mixture of haze and fog, but its main component is haze.

Distribution uniformity difference

Fog: Fog is unevenly distributed in the air, and the closer it is to the ground, the greater its density.

Haze: Haze particles are small, light and evenly distributed in the air.

Diurnal variation difference

Fog: Fog appears most easily from midnight to early morning, and basically dissipates in the middle of the morning.

Haze: The diurnal variation of smog is not obvious, and it may appear at any time of the day, or it may not dissipate all day.

Difference of boundary clarity

Fog: The boundary is very clear and obvious. After the "fog zone", it may be clear in Wan Li. Because of the small fog range, high density and obvious boundary.

Haze: The boundary between smog and the surrounding environment is not obvious, because smog has a wide range, low density and small particles, which has a certain transition effect with clear sky areas and has no obvious boundary.

Difference of visibility range

Fog: The horizontal visibility of fog is within 1 km, because the closer the fog is to the ground, the greater the density and the greater the influence on light, so the visibility is very low.

Haze: The horizontal visibility of haze is less than 10 km, because haze is evenly distributed in the air, with small particles and low density, which has certain influence on light, but the influence is not as big as fog and the visibility is low.

Difference in duration

Fog: short duration. Because the small water droplets in the fog will sink to the ground, the increase of atmospheric temperature will make the water droplets evaporate, so the fog will be less and less.

Haze: It lasts for a long time. Because the small solid particles in the smog are difficult to decompose, do not precipitate, and the digestion speed is slow.

Difference of influence on human body

Fog: Fog is a tiny water drop suspended in the air, which will land on the ground after a period of time and has little impact on people's life and health.

Smog: Smog is a small particle of various compounds such as dust particles, smoke particles and salt particles suspended in the air, which is very harmful to human health. Inhalation of respiratory tract for a long time will cause respiratory diseases and cardiovascular diseases.

Haze is a combination of fog and haze, which is common in cities. In many areas of China, fog and haze are combined as disastrous weather phenomena for early warning and forecasting, which are 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 number of fine particles (PM 2.5). Once the emission exceeds the atmospheric circulation capacity and carrying capacity, the concentration of fine particles will continue to accumulate. At this time, if it is affected by calm weather, it is easy to have a wide range of smog.