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What Is The Difference Between Activated Carbon And HEPA In An Air Purifier?
Oct 24, 2018

At present, the mainstream technology of air purifiers on the market is physical filtration technology based on activated carbon and HEPA. So what role does activated carbon and HEPA play in the air purifier?


Activated carbon is a kind of microcrystalline carbon material made of carbon-containing material with black appearance, developed internal pore structure, large specific surface area and strong adsorption  capacity. It is a commonly used adsorbent, catalyst or catalyst carrier. HEPA (High efficiency particulate air filter), Chinese means high efficiency particle filter.

The HEPA-compliant filter has an efficiency of 99.7% for 0.1 micron and 0.3 micron. The HEPA filter is characterized by air passing through, but fine particles cannot pass.

It has a particle removal efficiency of more than 99.97% for a diameter of 0.3 micron (1/200 of the hair diameter) and is the most effective filter medium for smoke, dust and bacteria.

The HEPA filter layer in an air purifier is generally formed into a shape that is repeatedly wrinkled. This is because HEPA is repeatedly folded and changed from a plane to the shape of the body.

The more the number of pleats, the wider the width of the pleats, and the larger the actual unfolded area, so as to effectively increase the contact area between the HEPA filter and the polluted air, increase the ability of the HEPA filter to treat polluted air, and prolong the purification of the HEPA filter. life.

The combination of activated carbon filter and medical grade HEPA filter in an air purifier plays a different role in removing cigarette contamination.


There are two main types of cigarette smoke: 1) particles of cigarette smoke (about 1 micrometer in diameter) 2) toxic and harmful gases including nicotine, carbon monoxide, etc. (the diameter of gas molecules is about 0.001 μm).

According to the medical grade HEPA filtration capacity (which can filter particles larger than 0.3 microns in air), the particles of cigarette  smoke can be completely filtered by medical grade HEPA filter. However,  medical grade HEPA filter cartridges do not filter the toxic and harmful gases of less than 0.3 micron in cigarettes. For this reason, the activated carbon is used for purification and removal by purifying the air.

Activated carbon can absorb all toxic and harmful gases including cigarettes, such as nicotine and carbon monoxide. Therefore, the activated carbon for air purification and the medical-grade HEPA filter have the functions of adsorbing toxic and harmful gases and filtering contaminated particles in the process of removing cigarette pollution.

Therefore, if only one medical grade HEPA filter or only activated carbon filter is installed in an air purifier, only the polluted particles of cigarette smoke can be filtered or only the toxic and harmful gases in the cigarette pollution can be adsorbed. Only the air purifier with medical grade HEPA and activated carbon filter can completely remove the pollution particles and toxic and harmful substances in cigarette smoke.