What is the ranking of real-time monitoring of air quality in China?

China's environmental air quality monitoring network covers the national, provincial, municipal and county levels. According to the different geographical location and climate, the national environmental air quality monitoring network includes regional environmental air quality monitoring, urban environmental air quality monitoring, background environmental air quality monitoring, greenhouse gas monitoring in pilot cities, acid rain monitoring, air quality monitoring affected by dust, atmospheric particle composition/photochemical monitoring, etc. The monitoring items mainly include SO2, nitrogen oxides, CO, CO2, CH4, O3, PM 10, PM2.5, PM 1VOCs (volatile organic compounds), five meteorological parameters, visibility and acid precipitation (including rainfall, pH, EC, sulfate ions, nitrate ions, fluoride ions, chloride ions, and so on).

First, air quality is judged according to the concentration of pollutants in the air, which reflects the degree of air pollution.

Air pollution is a complex phenomenon. At a specific time and place, the concentration of air pollutants is affected by many factors. Urban development density, topography and meteorology are also important factors affecting air quality. Negative oxygen ion concentration is one of the signs 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 per cubic centimeter 1000- 1500, it can be called "fresh air".

Second, the smaller the particle size, the deeper it enters the respiratory tract. Particles with a diameter of 10 micron are usually deposited in the upper respiratory tract, those with a diameter of 5 microns can enter the deep respiratory tract, and those with a diameter less than 2 microns can 100% penetrate into bronchioles and alveoli. Total suspended particulate matter refers to the general name of solid and liquid particulate matter floating in the air, and its particle size range is about 0. 1- 100 micron. Some particles, such as smoke and dust, are visible to the naked eye because of their large particle size or dark color. Others are small enough to be observed with an electron microscope. Generally, the particle size below 10 micron is called PM 10, also known as inhalable particles or floating dust. Inhalable particulate matter (PM 10) lasts for a long time in the ambient air, which 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, and their chemical and physical compositions vary greatly due to different places, climates and seasons. Inhalable particles usually come from motor vehicles running on unpaved asphalt and cement roads, the crushing and grinding process of materials and the dust raised by the wind.

Third, inhalable particles will accumulate in the respiratory system after being inhaled by people, causing many diseases. Contact with coarse particles will harm the respiratory system and induce asthma. Fine particles may lead to heart disease, lung disease, respiratory diseases and reduce lung function. Therefore, for sensitive people such as the elderly, children and people with heart and lung diseases, the risk is greater. In addition, the particulate matter in the ambient air is the main reason for reducing visibility and destroying the surface of buildings. Particles will also be deposited on the leaves of green plants, interfering with the process of plants absorbing sunlight and carbon dioxide and releasing oxygen and water, thus affecting the health and growth of plants.