Types of Purifiers
There are two categories of purifiers. Active purifiers work to eliminate contaminants in their natural environment, whereas passive cleaners wait for air to pass through their system. By purifying the air before individuals inhale harmful particles, active purifiers are more effective than most passive purifiers.
HEPA Filters (Passive Method)
To effectively remove allergens, HEPA filters require a continuously running fan. However, they are not effective in eliminating microscopic pathogens. Even if a filter traps viruses, they may still be viable, but the likelihood of them causing another infection is minimal. Although the HEPA system is highly effective in its designated function, it is inappropriate for tasks that exceed its capabilities.
Intentional Ozone Generation
Ozone can change the chemical structure of molecules and kill off bacteria and viruses, including COVID-19. However, it can also be harmful to plants and cause lung irritation. Only trained professionals should use it with proper safety protocols. It effectively cleans buildings damaged by fire, smoke, or floods.
Active ionizers charge air molecules using a carbon filter brush or electrode, which generates ions that are released naturally or through a fan. Unlike passive systems, active ionizers attract and cling to particulates in the air, charging them and causing them to come together to form larger particles. These larger particles eventually become too heavy to stay airborne and fall to surfaces in the room. Alternatively, the charged particulates may cling to walls or surfaces like a balloon interacts with a sweater.
Photocatalytic Oxidation (PCO)
When sunlight interacts with the earth's atmosphere, it generates unstable molecules known as reactive oxygen species. The most significant molecule is the hydroxyl radical, which arises when sunlight extracts a hydrogen atom from water.
Hydroxyl radicals are constantly searching to stabilize themselves by bonding with other atoms, such as other hydroxyl radicals, to create hydrogen peroxide, carbon, or hydrogen from pollutants in the air. This capability of bonding with atoms in viruses, bacteria, and fungi makes hydroxyls effective in deactivating them.
One of the main benefits of PCO air purification method is that it actively treats the air instead of waiting for contaminants to reach the purifier. This method is effective against allergens, particulates, and some pathogens. Additionally, fanless ionizers are known for their quiet operation.
The indoor PCO technology mimics the natural process of purifying air by using a shielded UV bulb to shine on a catalyst, typically titanium dioxide. This creates hydroxyls and other reactive oxygen species, which circulate in the room to eliminate viruses, bacteria, mold, odors, and VOCs.
The outdated PCO technology can create harmful byproducts like ozone and formaldehyde. It is also ineffective in dealing with dust, allergens, and particulate matter. Nowadays, advanced photocatalysis is the preferred method.