There are so many air pollutants out there and as a result there are many types of air filtrations as well. To be honest I don’t like filters because I believe that we have to reduce and avoid generating pollutants in the first place, but sometimes it’s hard.
High-Efficiency Particulate Arrestance (HEPA) Filters
HEPA filters are designed to catch particulate matter >1µm to >0.3µm with an efficiency of 85% to 99.999995%. We can translate that into:
- Pollen (5-100 µm)
- Mold (2-20 µm)
- Pet Dander (0.5-100 µm)
- Dust Mite Debris (0.5-50 µm)
- Bacteria (0.3 -10 µm)
Carbon Air Filters
Activated Carbon filters have small absorbent pores that chemically react to pollutants like VOCs as they pass through the filter. The activated carbon absorbs the odors and gasses and neutralises them by bond the pollutants with the carbon. They always combine HEPA filters with active carbon filters because they can’t remove dust and other allergens alone.
Silver Nanoparticles Coated Filter
Silver Nanoparticles Coated Filters have a range of negative effects on virus strains and bacteria and they can destroy the membrane of a cell and deactivate them. They use silver as a natural antibacterial as result there are HEPA filters with Silver Nanoparticles Coated that have been proved to be 98% effective against common flu virus.
Ionic Air Filters/Purifiers
Typically, they produce negatively charged ions aka anions, which then attract positive particles in the air. As the particles make contact with the anions , these particles become too heavy to remain airborne and fall to the floor. Some ionisers are armed with some static plates which trap all those particles, but you have to clean them regularly. A very negative aspect of Ionic air filters is that they produce ozone O3 as a by-product**, which has classified as a toxic gas that causes lung damage. Some companies claim that their ioniser doesn’t produce Ozone but it’s hard not to.
- Removes ultra-fine particles as small as 0.01µm
- Sterilizes bacteria, viruses, smoke, and other toxic fumes
UV Light Air Purifiers
High intensity UV-C light (240-280 nm) is strong enough to break down most carbon based organic compounds like bacteria and other pathogens by breaking the molecular bonds in their DNA. As a result they are designed to destroy micro-organisms such as germs, bacteria and mold and not to catch allergens and dust like a HEPA filter. This is why many companies combine a HEPA filter and UV Light. This is not a quick process, the pathogens must pass through the UV light multiple times in order to be destroyed.
NTP Non Termal Plasma Purifiers
This is fairly new technology also called Cold Plasma that works like an Ionizer but it splits Oxygen O2 molecules into positive and negative ones. These single oxygen atoms are highly reactive and stick to particles, bacteria, viruses or gases to destroy them or to turn them into harmless substances. They also produce Ozone as a by-product** but in less quantities around ∼0.0058PPM, the World Health Oraginization, EPA and many country standards have set the maximum level of ozone concentration at 0.05PPM.
**The shocking truth is that many devices in your home produce ozone by-product like TVs, computers, electric mixers, hair dryers and ceiling fans.