The air purifiers are not all the same, they differ mainly in the main component of the filtration system. The most common component is a HEPA type filter, electrostatic filter, or filtering through water How do the methods differ?
HEPA filter purifiers are the most efficient of all. Depending on its class, the filtering ability is close to 100%, thus removing almost all impurities from the air. The filter binds these particles deep into its structure and does not let them further. Therefore, its capacity is limited and it needs to be replaced once in a while.
Electrostatic filter binds impurities from the air using static electricity. The filtration effect is slightly worse than in most HEPA type filters - around 95%. If cleaned regularly, it does not need to be replaced, unlike HEPA. But it is necessary to take into account that maintenance can cost you enough time and nerves, the filter can be soiled by impurities.
Also filtration through water is less effective than HEPA in smaller particles but it works great for larger pollen and dust type impurities. In addition, this principle effectively humidifies the air.