Can UV-C Kill Mold?

Properties of UV

• Overexposure to UV-C light can irritate the skin and eyes. After exposure to high levels of UV-C lights, symptoms usually occur within six to 12 hours and last up to 48 hours. The severity of this irritation depends on the strength of the light and the length of exposure. The effectiveness of UV-C light in killing mold and other microbial organisms also depends on the strength and duration of exposure to this light. UV-C light kills these organisms by disrupting their ability to grow at the cellular level.

Germicidal Uses

• UV-C light is used to kill microbial organisms in a variety of settings. Two common applications are in HVAC systems and biological safety cabinets. Biological safety cabinets equipped with UV-C lights are designed to sterilize equipment through exposure to measured doses of ultraviolet light. In HVAC systems, these lights are used to sterilize sections of vents, evaporating coils, drain pans and other areas that can promote the growth of mold.

Advantages of UV-C

• UV-C lights are effective for controlling the growth of mold. These lights have several advantages over other methods for eliminating mold. Chemical cleaning agents and fungicides are often toxic and leave behind undesirable chemical residues. Although UV-C light is a skin and eye irritant it does not leave behind toxic residue. High efficiency particulate air filters are highly effective at removing mold from the air but these filters can become fertile ground for the growth of mold under damp conditions. HEPA filters are only effective at trapping particles measuring 0.3 microns or larger while UV-C lights are effective against microbial particles of all sizes.

Considerations

• UV-C lights are only effective at killing mold when it is exposed to UV-C light over a period of time. This makes UV-C effective at sterilizing stationary objects but less effective at neutralizing airborne particles. UV-C light does not penetrate through layered material, making it ineffective at sterilizing layers of mold growing under a layer of dirt. UV-C light is less effective in regions with a humidity above 70 percent. UV lights require regular cleaning to remove dirt and dust that can accumulate on the bulb, preventing it from working.