UV (Ultraviolet) Air Purifiers

Ultraviolet light has been used for years to sterilize medical equipment, process food, and purify water. In recent years it has been introduced as another technology for enhancing indoor air quality (IAQ). It has been a very attractive method because it actually destroys harmful microbes such as bacteria and viruses, mold, and VOCs (volitile organic compounds ) which are often too small (< .3 microns) for removal for filters employed in the other air filtering systems.

The UV air purifier is often combined with a HEPA filter. A recent study has shown that hybrid HEPA-UV air filters can reduce bioaerosol contamination. A major study that was published in the well known medical journal The Lancet (11/28/2003) discovered that the UV purifiers on the air conditioning coil had resulted in a 99% reduction of microbial organisms on the irradiated surfaces inside the ventilation system and there was also a 40% reduction in respiratory symptoms.

A UV system can also be combined with HVAC systems where the UV unit will be placed inside the duct itself which will then allow for a repeated, multipass exposure to the UV light as the air circulates through the room..

How does the ultraviolet light work?

The ultraviolet light breaks down the organic molecular bonds as the micro-organisms pass by the UV rays. This is  known as ultraviolet germicidal irradiation (UVGI). The types of micro-organisms which the UV light can destroy are germs, viruses, bacteria, fungi (molds), as well as chemicals and odors, etc. The UV light is shielded inside the unit and is then simply sterilizes only the air which passes through the purifier.

There are two major components to the UV system:

1. The intensity of the source where a power source can deliver greater UV energy and increase its efficacy.
2. The greater length of time that the pollutant is exposed to the UV light along with the intensity will result in a higher kill rate.

UV light is now routinely used with with HEPA air filters which serves to remove then other types of pollutants.

Studies have shown the efficacy of UV light  in reducing germ levels. They have now been widely used in hospitals and along with reducing the amount of pathogens in the air, they also have been very effective in reducing and eliminating mold and mildew.

For households, the usual method of UV purification is with a UV air purifier. As the air passes through the purifier unit, the microbial organisms and other pollutants are irradiated. Since the time involved here amounts to a few milliseconds as the air is passing by, the UV ray must be powerful enough to delivery the necessary intensity to eradicate the contaminants.

The indoor air quality (IAQ) is considerably improved through multiple exposures to the UV radiation.