It takes 3 to 15 years for indoor formaldehyde and pollution sources to disappear, so it is necessary to use air purifiers, but the key is which brand has the best effect, which depends on the standard certification of products. You must be certified by British Allergy Association, Energy Star, Tsinghua University Building Environment Testing Center, European Allergy Research Foundation, CQC Safety and Electromagnetic, and American Household Appliance Manufacturers Association to be more at ease. The cumulative purification amount of formaldehyde should reach F4 level, the decibel should reach about 2 1 decibel, and the clean air amount of CADR should reach 565438+ 100 m3/h, which is the perfect polite purifier.