What are the Different Roles of Activated Carbon and HEPA in an Air Purifier

At present, the mainstream technology of air purifier on the market is the physical filtration technology based on activated carbon and HEPA.So what are the roles of activated carbon and HEPA in an air purifier?

Activated carbon is a kind of carbon material made of black appearance, developed internal pore structure, large specific surface area, strong adsorption capacity of a class of microcrystalline carbon material, is a commonly used adsorbent, catalyst or catalyst carrier. HEPA(High efficiency particulate air Filter)

HEPA filters are 99.7% efficient for 0.1 micron and 0.3 micron. HEPA filters are designed to allow air to pass through, but not for small particles.

It can remove particles with a diameter of 0.3 micron (1/200 of the diameter of a hair) with an efficiency of 99.97% and is the most effective filter medium for pollutants such as smoke, dust and bacteria.

The HEPA filter layer in an air purifier is usually folded repeatedly.This is because HEPA is repeatedly folded from a flat surface into a solid shape.

The larger the number of folds, the wider the width of folds, and the larger the actual expanded area, the more effectively increasing the contact area between HEPA filter element and the polluted air, increasing the capacity of HEPA filter element to deal with the polluted air, and extending the purification life of HEPA filter element.

The combination of activated carbon filter element and medical HEPA filter element in air purifier plays different roles in removing cigarette pollution.

There are mainly two kinds of substances in cigarette smoke: 1) particles of cigarette smoke (about 1 micron in diameter) 2) toxic and harmful gases including nicotine, carbon monoxide, etc. (about 0.001 micron in diameter of gas molecules).

Depending on the filtering capacity of a medical-grade HEPA (which can filter particles larger than 0.3 micron in the air), cigarette smoke particles can be completely filtered with a medical-grade HEPA filter.However, the medical-grade HEPA filter does not filter the toxic and harmful gases in cigarettes smaller than 0.3 micron, so the air is purified and activated carbon is used to remove it.

Activated carbon can absorb all toxic and harmful gases including nicotine and carbon monoxide in cigarette pollution.Therefore, in the process of removing cigarette pollution, activated carbon and medical-grade HEPA filter elements are used for air purification to absorb toxic and harmful gases and filter pollution particles, respectively.

So if an air purifier has only a medical-grade HEPA filter or an activated carbon filter, it can only filter particles from cigarette smoke or absorb toxic or harmful gases from cigarette pollution.Only an air purifier equipped with both a medical-grade HEPA and an activated carbon filter can truly clean out the pollution particles and toxic and hazardous gases in cigarette smoke.