Can air purifiers effectively lower indoor air pollution? | Updated: 2022-03-16
Currently, particulate matter filtration and purification technologies are relatively mature. Air purification products can reduce PM2.5 mass concentrations in offices and homes.
The purification time varies according to the area treated and the efficiency of the air purifiers. 
How air purifiers work
There are many working principles involved in air purifiers, such as filtration, electrostatic adherence, chemical reaction and combined purification. Filtration refers to using a fan to draw air into the machine and filtering it with a built-in strainer.
Chemical reaction refers to using various chemical reaction technologies such as those of silver ion and negative ion technology to effectively purify indoor air. Combined purification refers to combining filtration technologies with chemical reactions, which is adopted by most air purifiers today.
New national standard for air purifiers
A newly revised national standard for air cleaners (GB/T 18801-2015) has been put in place. 
The new national standard defines some core indicators affecting the purification effect of air purifiers, namely CADR (clean air delivery rate), CCM (accumulated purification amount) and so on. Higher CADR values indicate a faster purification efficiency, while higher CCM values means that the air purifier can remove more pollutants. 
How to choose air purifiers
First, the pollutants that need to be purified determine the air purifiers that consumers should buy. To remove PM2.5, an air purifier with that specific capability is the best choice.
Second, consumers should choose a qualified manufacturer that produces air purifiers in accordance with the national standard. 
The actual purification effect is also related to room area, energy efficiency and the working time of the individual air purifier. 
Pay attention to secondary pollution
The purification materials have service lives. After a period of time, these materials will have absorbed particulate matters or other microorganisms. Therefore, they should be changed according to pollution levels and length of service. 
The air purifiers that work on the electrostatic adsorption principle run the risk of generating ozone, which is harmful to the respiratory system, especially among the elderly and children. The increase in ozone concentration may cause untoward effects on the human body.
Besides, turning on air purifiers in a closed room for a long time may result in a lack of oxygen, reduced indoor humidity and excessive noise. It is necessary to adjust the usage time of air purifiers and to open windows to let fresh air in in accordance with the indoor air pollution levels and the responses of your body.