UVC light was discovered to have germicidal and disinfection capability in the late 1800's, and the application of UV air disinfection started in the 1920's to combat the spread of Tuberculosis and Measels. In parts of the world that still have high instances of TB still use UVC for air disinfection, and is growing in use again here in the United States as the effectiveness of this application to things like the common cold and influenza. Studies have been done showing Upper Air UV disinfection to remove over 98% of influenza from a space treated with UVC.
Pathogens spread by airborne transmission has been difficult to control. Even with the introduction of the Clean Air Act there have been little improvements to stopping airborne pathogens. What makes them so difficult to control is how small they are, even HEPA filters will only catch about half of Influenza virons due to their small size, bacteria is larger but still typically less than one micron and if your facility is following LEED standards and using MERV-13 air filters again half or less of the airborne bacteria that encounter the filter are stopped.
The other difficulty in using your HVAC system and filtration for virus and bacteria pathogen control is the particle has to travel all the way to the filter before it is caught, while Upper Air UVC kills the pathogen in the space it was generated, creating a much faster and effective means of disinfecting and sterilizing the air. It works be creating an active field of UV-C light in the upper portion of the space.
The natrual convection and mixing of the air in a room ro larger space (OR and Cleanrooms are differnt as they operate on laminar flow) will cause the pathogen to eventually enter this zone of UV-C irradiation, then it takes just seconds of exposure for the pathogen to be deactivated. Because this zone is above the occupied space there is no risk or danger to occupants, allowing for the space to be disinfected while occupied.
There have been a lot of mis-uses and equipment sold in the past few years that use the germicidal and disinfection properties of UV-C light that are either very expensive or use the technology poorly. Upper Air however is a long standing application that has neynd proven it's effectiveness, so much so that countries with a high amount of deadly airborne pathogens liek South Africa require UV air disinfection units in their hospitals.
In the United States, we are fortunate to have low instances of TB and these other serious diseases, but that doesn't mean we need to continue to turn a blind eye to such an inexpensive and effective way to control other diseases and sickness like Influenza and the Common Cold.
For more information, or to get a quote on protecting your students, co-workers, tennants, paitents, and othe rbuilding occupants against Influenza, the Common Cold, and all other airborne pathogens simply visit our UVC page here.