What does smog mean?

The meaning of smog: the general term for fog and haze.

Haze is a combination of fog and haze. Smog is very 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. 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. In 20 13, "smog" became the key word of the year.

In June 5438+10, four smog processes enveloped 30 provinces (autonomous regions and municipalities). In Beijing, only five days are not foggy. It is reported that less than 65,438+0% of the 500 largest cities in China meet the air quality standards recommended by the World Health Organization. Meanwhile, among the 65,438+00 most polluted cities in the world, 7 are in China.

Identification method:

The similarity between fog and haze is sight distance obstacle. However, the reasons and conditions for the formation of fog and haze are quite different. Fog is a large number of tiny water droplets or ice crystals floating in the air, and the formation conditions should have a high water vapor saturation coefficient.

Generally speaking, when the relative humidity is less than 80%, the visibility deterioration caused by blurred vision is caused by haze, while when the relative humidity is greater than 90%, the visibility deterioration caused by blurred vision is caused by fog.

When the relative humidity is between 80% and 90%, the deterioration of visibility caused by blurred vision is caused by the mixture of fog and haze, but its main component is haze. The thickness of smog is relatively large, which can reach 1 ~ 3 km.