How effective are activated carbon filters and HEPA filters in removing formaldehyde?

HEPA filters and activated carbon filters each have their own features and benefits in removing formaldehyde:

1. HEPA filter::
   • It is mainly used to remove airborne particles such as dust, pollen, viruses and bacteria.
   • For gaseous pollutants such as formaldehyde, HEPA filters do not have the ability to remove them by themselves, but some HEPA filters incorporate an activated carbon layer to remove formaldehyde and other harmful gases through the adsorption of activated carbon.
2. Activated Carbon Filter::
   • Remove harmful gases in the air such as formaldehyde, benzene, TVOC (Total Volatile Organic Compounds) through the adsorption of activated carbon.
   • Activated carbon filters can effectively adsorb these harmful gases and reduce indoor pollution.

In practice, a combination of HEPA filters and activated carbon filters are often used for more effective formaldehyde removal. This allows the HEPA filter to be utilized to remove particulate matter while the activated carbon filter is utilized to remove gaseous pollutants. Some air purifiers will integrate both filters into one unit to provide total air quality control.

It is worth noting that the activated carbon filter needs to be replaced regularly, because the adsorption capacity of activated carbon is limited, when the adsorption reaches saturation, it will not be able to continue to adsorb formaldehyde, and may even release the adsorbed formaldehyde, resulting in secondary pollution. Therefore, the use of activated carbon filter, should pay attention to regular replacement to maintain its purification effect.

When choosing an air purifier, you should consider its CADR value (Clean Air Delivery Ratio) and CCM value (Cumulative Cleaning Capacity), which are important indicators of an air purifier's performance.The higher the CADR value, the higher the purification efficiency of the purifier; the higher the CCM value, the higher the purification efficiency of the purifier.