The use of Ultra Violet light for reduction and removal of bacteria ( germs) on surfaces has been used for years in the food industry. In the early years “black lights” were placed above the produce in the grocery stores to help maintain a bacterial free environment. While UV lights are no longer used in these food operations, they are used in the residential and light commercial HVAC markets.

We are all familiar with the term UV as we hear this term used when they describe the rays from the sun as being UV A or B or C. UV A is the most dangerous because the UV A wavelength can be harmful to human skin as well as various material. Long term exposure can damage the skin and increase the possibility for skin cancer.

The use of UV Lights for reduction and removal of bacteria in heating/cooling systems, ductwork and air handler cooling coils has been around for over 25 years. The UV Lights produce a specific wavelength; approximately 285 nanometers, designed to kill or destroy the nuclei of most molds and bacteria. UV has minimal effect on viruses.

For many years UV lights were placed in the return air side of the ductwork close to the air handler and were supposed to kill or destroy the mold and bacteria as it passed by the UV Lamps. There were a number of challenges with this installation configuration. First, the UV lights were often not shielded and the dirt, dust and particulate in the return air stream would coat the lamps and significantly reduce the effectiveness of the lamps. And, second, the speed at which the air passed  by the lamps did not allow enough residence time or light exposure time on the mold or bacteria to really kill or destroy the particle. Even adding shielding to minimize dust build up on the lamps didn’t solve this problem.

Since most mold and some bacteria require a source of moisture or water a more obvious place to locate the UV Lights was over or close to the cooling coils located in the air handler.  This made more sense as it allowed the UV Lights to irradiate the entire coil area constantly and minimize the ability for mold and bacteria to grow on the coils surface. It also didn’t rely on air flow speed and the lights could be shielded in such a way as to direct the UV light source onto the coils and reduce the build up of dust on the lamps.

While this approach is much more effective it still doesn’t answer the question about removing the airborne mold, bacteria and other allergens. Using a UV light alone is only a small part of the solution.

Pure Air Systems, offers a complete line of  both media air filters and HEPA based air filtration systems used in conjunction with HVAC systems. The line of BioPanel furnace filters includes a dual-layer, polyester ring panel filter that offers a  MERV 8 filter with a high dust holding capacity, tight fitting and low pressure drop. The HEPA filter systems offered by Pure Air Systems have been in use since 1985 and are the most well known HEPA systems in the world.

For complete removal of harmful airborne pathogens and allergens in your home, office, laboratory or medical facility, Pure Air Systems has the solution. For more information go to our website at: www.pureairsystems.com.




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About the Author: Don Musilli

My name is Don Musilli. I started Pure Air Systems in 1985 and then sold it in 2006. I continue to consult for PAS and write their blog and control their Twitter account. I also, on occasion, make changes to the website. The company is now almost 26 years old and has been a major player in offering commercial grade, high performance HEPA and Carbon based filtration systems for the commercial, institutional, industrial and residential markets.

I currently reside in Englewood, Florida where I write blogs and do social media marketing for a number of clients.


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