The answer to smog reading is the final review of the sixth grade Huanggang Small Champion Volume II (Reading). At first, smog was a general term for fog and haze.

Haze is a general term for fog and haze, and it is a general term for two similar and indistinguishable weather phenomena mentioned together.

(2) Fog is a weather phenomenon that the horizontal visibility drops below 1000 meters due to a large number of tiny water droplets or ice crystals suspended in the air near the ground; When the visibility of horizontal energy is 1000- 10000 meters, it is called light fog. Because the light scattered by fog composed of water droplets or ice crystals has little to do with the wavelength of light, the fog looks milky white or bluish white.

Haze is the phenomenon that dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles in the air make the atmosphere turbid, resulting in horizontal visibility less than 10000 meters. The smog composed of dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles has a larger light ratio and a longer scattering wavelength, so the smog looks yellow or orange-gray.

④ Fog and haze often appear together. The relative humidity of air is an important basis for distinguishing fog from haze. Generally speaking, when the relative humidity is less than 80%, the deterioration of air visibility is caused by smog, and people are used to calling the weather at this time a foggy day; When the relative humidity is greater than 90%, the deterioration of air visibility is mainly caused by fog, which is usually called foggy day. When the relative humidity is between 80-90%, the deterioration of air visibility is caused by the mixture of fog and haze, which is generally called haze.

⑤ In smoggy weather, PM2.5 is the "culprit". There are many main sources: first, road dust and construction dust; The second is automobile exhaust; Third, the waste gas pollution produced by factories; The fourth is the pollutants emitted by low-altitude coal burning during heating in winter; Fifth, the smoke and dust produced by the burning of biomass (straw and firewood) and garbage incineration.

⑥ These polluted particles, together with bacteria and viruses, are on water droplets, which have an impact on human respiratory tract and may cause acute upper respiratory tract infection, acute tracheobronchitis, pneumonia, epidemic cerebrospinal meningitis and other diseases. 1952 65438+In February, the fog in London, England lasted for a week, and smoke and dust accumulated at low altitude. During this period, 4,700 people died of respiratory diseases. After the fog dispersed, more than 8,000 people died in the fog, which shocked the world. People listed the fog disaster in London as one of the top ten natural disasters in the world in the 20th century. This is an obvious example of harm. More often, smog unconsciously harms people's health.

⑦ In foggy days, reduce window opening, reduce going out, avoid cycling when going out, wear formal and qualified masks, and eat more foods that clear and moisten the lungs. But the most fundamental thing is to take measures to "reduce emissions and eliminate dust" from the source. This method can not only reduce the water vapor in the air caused by greenhouse gases, but also reduce the condensation nuclei in the air, thus controlling the frequent occurrence of smog. In this regard, London has set an example: 1956, Britain promulgated the Clean Air Act, which made a big fuss about "emission reduction and dust removal" and now it has achieved results. There used to be dozens of foggy days every year, but now it has dropped to five days, and the world-famous "foggy city" is no longer worthy of the name. Puweixin, American importer, have a nice day, Kitty.