Through the circulation of indoor air, the content of harmful substances in indoor air can be reduced, thus reducing the harm of such substances to human body. People often close doors and windows in winter, so the indoor and outdoor air can't circulate. Not only the formaldehyde content in indoor air will increase, but also radon will accumulate continuously, even reaching a very high concentration.
Advantages: good effect and no cost.
Disadvantages: It takes a long time, and formaldehyde removal generally takes more than three years.
Extended data:
Formaldehyde, chemical formula HCHO or CH? O, molecular weight 30.03, also known as formaldehyde. Colorless, irritating to people's eyes and nose. The relative density of gas is 1.067 (air = 1), and the density of liquid is 0.8 15g/cm? (-20℃)。
Melting point -92℃, boiling point-65438 09.5℃. Soluble in water and ethanol. The highest concentration of aqueous solution can reach 55%, usually 40%. It is called formaldehyde water, commonly known as formalin, which is a colorless liquid with an irritating smell.
It has strong reducibility, especially in alkaline solution. Can burn, steam and air form an explosive mixture, and the explosion limit is 7%-73% (volume). The ignition point is around 300℃.
It can be prepared by dehydrogenation or oxidation of methanol under the catalysis of metals such as silver and copper, and can also be separated from oxidation products of hydrocarbons. It can be used as raw materials for phenolic resin, urea-formaldehyde resin, vinylon, urotropine, pentaerythritol, dyes, pesticides and disinfectants.
Industrial formaldehyde solution generally contains 37% formaldehyde and 15% polymerization inhibitor methanol, and its boiling point is 10 1℃.
2017101On October 27th, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization included formaldehyde in the list of carcinogens.
References:
Baidu encyclopedia-formaldehyde