Air pollution means that the air contains one or more pollutants. The amount, nature and time of its existence can harm human, plant and animal lives, damage property, or interfere with a comfortable living environment, such as the presence of odours. In other words, as long as the quantity, nature and time of a particular substance are sufficient to affect humans or other organisms and property, we can call it air pollutants; and the phenomenon caused by its existence is air pollution. What method do I need to prevent air pollution?

1. Reduce the emission of pollutants

• Reform the energy structure and adopt pollution-free energy (such as solar, wind, and water power) and low-polluting energy (such as natural gas, biogas, alcohol).

• Pre-treatment of fuels (such as fuel desulfurization, coal liquefaction and gasification) reduces atmospheric pollution during combustion.

• Improve combustion equipment and combustion technology (such as reforming stoves, using boiling furnace combustion, etc.) to improve combustion efficiency and reduce harmful gas emissions.

• Using non-pollution or low-pollution industrial production processes (such as not using or using less pollution-prone raw materials, using closed-loop technology, etc.).

• Strengthen corporate management to reduce accidental emissions and escapes.

• Clean up and properly dispose of industrial, domestic and construction waste residues in time to reduce ground dust.

2. The principal contradiction in the governance of emissions

After the measures mentioned above are taken in the combustion process and industrial production process, some emissions are discharged into the atmosphere. The emission concentration and total emissions should be controlled so that they do not exceed the area's environmental capacity. The main methods are:

① Use various dust collectors to remove smoke and different industrial dust.

②Use gas scrubbers to treat harmful gases (such as sodium carbonate and other alkaline solutions to absorb sulfur dioxide in exhaust gas; use alkaline absorption to treat nitrogen oxides in exhaust fumes).

③Apply other physical (such as condensation), chemical (such as catalytic conversion), physicochemical (such as molecular sieve, activated carbon adsorption, membrane separation) methods to recycle valuable substances in the exhaust gas, or make harmful gases harmless.

3. Develop plant purification

Plants have the functions of beautifying the environment, adjusting the climate, intercepting dust, absorbing harmful gases in the atmosphere, and continuously and continuously purifying the atmosphere in a large area. Under the circumstances, plant purification is an effective method. The planned and selective expansion of green spaces in cities and industrial sites is a long-term and multi-functional measure for comprehensive air pollution prevention and control.

4. Utilize the self-purification ability of the environment

The atmospheric climate's self-purification has physical, chemical effects (diffusion, reduction, oxidation, reduction, substitution washing, etc.) and biological effects. Meteorological conditions are related, understanding and mastering the laws of meteorological changes, and making full use of the atmosphere's self-purification ability can reduce the concentration of impurities in the atmosphere and avoid or reduce the hazards of air pollution. For example, based on the changes in aerodynamics and thermodynamics of the atmosphere at different heights in different regions, the size of the chimneys in the different areas can be reasonably determined so that the atmospheric pollutants discharged through the vents can be rapidly diffused and replaced in the atmosphere.

Air pollution hazards

Harm to human health:

(1) People need to breathe air to maintain life. An adult lives about 20,000 times a day and inhales 15-20 cubic meters of air. Therefore, polluted air has a direct impact on human health.

(2) The harm of air pollutants to the human body is multifaceted. The main manifestations are respiratory diseases and physiological dysfunction, and the mucosal tissues such as the eyes and nose are irritated and get sick.

Harm to plants:

(1) Atmospheric pollutants, especially sulfur dioxide and fluoride, are very harmful to plants.

(2) When the concentration of pollutants is high, it will cause acute harm to plants, causing spots on the surface of plant leaves or directly causing leaves to wither and fall off.

(3) When the concentration of pollutants is not high, it will cause chronic damage to plants, causing plant leaves to chlorosis, or no harmful symptoms can be seen on the surface. Still, plants' physiological functions have been affected, resulting in decreased plant yields and quality changes. Bad.

Affect the climate:

(1) Reduce the amount of solar radiation reaching the ground: a large number of soot particles emitted into the atmosphere from factories, power stations, cars, and home heating equipment make the air very turbid, block the sunlight, and reduce the amount of solar radiation reaching the ground.

(2) Increase the amount of atmospheric precipitation: many of the particles discharged from large industrial cities have the effect of condensation nuclei.

(3) Acid rain: Sometimes, the rain falling from the sky contains sulfuric acid. This kind of acid rain is formed by the oxidation of the pollutant sulfur dioxide in the atmosphere to form sulfuric acid, created with the fall of natural precipitation.

(4) Increasing the atmospheric temperature: Over large industrial cities, due to a large amount of waste heat emitted into the air, the air temperature near the ground is higher than that of the surrounding suburbs. This phenomenon is called the "heat island effect" in meteorology.

(5) Impact on global climate: In recent years, people have gradually noticed the impact of air pollution on global climate change.