Indicators On Air Quality

When it comes to air quality indicators, the first reaction of most people should be PM2.5. This is also the main source of pollution in haze weather. PM2.5, also known as fine particles, is only particles with an equivalent diameter less than or equal to 2.5 microns in the air. It can be suspended in the air for a long time, and it is easy to carry toxic and harmful substances, which has a great impact on human health and environmental quality. However, as far as indoor air is concerned, only one PM2.5 indicator is too thin. According to the "White Paper on China’s Indoor Air Pollution Status in 2019", the top two sources of indoor air pollution are formaldehyde and VOC, accounting for 97.3% of the total unqualified points, which deserve our attention. Everyone knows about formaldehyde, especially after the renovation or the use of glue or paint, the indoor formaldehyde content is high. We will also pay attention to emission and removal of formaldehyde. But VOC is not clear to many people. VOC refers to volatile organic compounds. Another indicator name that you occasionally see is total volatile organic compounds. The U.S. Environmental Agency (EPA) defines VOC as: except for carbon monoxide, carbon dioxide, carbonic acid, metal carbides, carbonates and ammonium carbonate, any carbon-containing compound that participates in photochemical reactions in the atmosphere. Mainly from combustion products such as coal and natural gas, smoking, heating and cooking smoke. In interior decoration, it mainly comes from latex paint, wallpaper, floor, thermal insulation materials, adhesives, etc.