What is air quality?

Air quality reflects the degree of air pollution, which is judged based on the concentration of pollutants in the air. Air pollution is a complex phenomenon, and the concentration of air pollutants at a specific time and place is affected by many factors. The size of man-made pollutant emissions from stationary and mobile pollution sources is one of the most important factors affecting air quality, including exhaust from vehicles, ships, and aircraft, industrial pollution, residential living and heating, and garbage incineration. Urban development density, topography and meteorology are also important factors affecting air quality.

In addition, the concentration of "negative oxygen ions" is one of the indicators of air quality. According to the standards of the World Health Organization, when the concentration of negative oxygen ions in the air is higher than 1,000-1,500 per cubic centimeter, it can be called "fresh air." [1]

Chinese name

Air Quality

Foreign name

Air Quality

Classification

Reduced oxidized petroleum type, etc.

Pollution sources

Industrial boiler transportation fires

Hazards

Harmful to human body and plants ; Impact on climate

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Pollutants

Air pollution pollutants

Smoke, total suspended particulate matter, respirable particulate matter (PM10), fine particulate matter (PM2.5),

Nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, volatile organic compounds and more.

Air pollution sources can also be divided into two categories: natural and man-made. Natural pollution sources are formed due to natural causes (such as volcanic eruptions, forest fires, etc.), while man-made pollution sources are formed due to people engaging in production and living activities.

Respirable particulate matter

Respirable particulate matter refers to particles suspended in the air with an aerodynamic equivalent diameter ≤ 10 microns.

PM2.5

Fine particles are also called fine particles, fine particles, and PM2.5. Fine particulate matter refers to particles in ambient air with an aerodynamic equivalent diameter of 2.5 microns or less. It can be suspended in the air for a long time. The higher its concentration in the air, the more serious the air pollution is. Although PM2.5 is only a small component of the earth's atmosphere, it has an important impact on air quality and visibility. Compared with coarser atmospheric particles, PM2.5 has a small particle size, a large area, and strong activity. It is easy to carry toxic and harmful substances (such as heavy metals, microorganisms, etc.), and has a long residence time in the atmosphere and a long transportation distance. Therefore, it has a greater impact on human health and atmospheric environment quality.

PM10

Total suspended particulate matter refers to the general term for solid and liquid particles floating in the air, [1] and its particle size range is approximately 0.1-100 microns. Some particulate matter can be seen by the naked eye because of its large particle size or black color, which is smaller than inhalable particulate matter such as smoke. Some are so small that they can only be seen with an electron microscope. Particles with a particle size of less than 10 microns are usually called respirable particulate matter.

The concentration of respirable particulate matter is expressed in milligrams of respirable particulate matter per cubic meter of air. In the revised "GB 3095-1996 Ambient Air Quality Standard" promulgated and revised by the State Environmental Protection Administration in 1996, flying dust was renamed respirable particulate matter as the official atmospheric environmental quality standard.

The smaller the diameter of the particles, the deeper they enter the respiratory tract. Particles with a diameter of 10 microns are usually deposited in the upper respiratory tract, particles with a diameter of 5 microns can enter the deep part of the respiratory tract, and particles below 2 microns can penetrate 100% into the bronchioles and alveoli. Total suspended particulate matter refers to the general term for solid and liquid particles floating in the air, with a particle size range of approximately 0.1-100 microns. Some particles are visible to the naked eye due to their large size or black color, such as smoke. Some are so small that they can only be seen with an electron microscope. Particulate matter with a particle size of less than 10 microns is usually called PM10, also known as inhalable particulate matter or flying dust. Inhalable particulate matter (PM10) lasts for a long time in the ambient air and has a great impact on human health and atmospheric visibility. Some particulate matter comes from direct emissions from pollution sources, such as chimneys and vehicles. Others are fine particles formed by the interaction of sulfur oxides, nitrogen oxides, volatile organic compounds and other compounds in the ambient air. Their chemical and physical composition changes depending on location, climate, and season of the year. Very big. Respirable particulate matter usually comes from motor vehicles driving on unpaved asphalt or cement roads, the crushing and grinding process of materials, and dust raised by the wind.