Sophisticated particle sampling techniques have shown tremendous concentrations of suspended particulate material in the indoor air that we breath everyday. Even in relatively "clean", smoke free indoor air, particle counts in the range of 1 million parts per cubic foot have been observed. Particles smaller than .1 micron generally account for 80% of the total number. Obviously, the vast majority of these particles are non-pathogenic and not likely to cause any adverse health effects. Just as obvious is the fact that many diseases are transmitted through the air, from an infected individual to others sharing the same breathing space. The problem is how to best interrupt and control the spread of airborne transmissible disease in enclosed indoor spaces, to improve the lives and health of occupants.
Air filtration via media type filters is the popular method of air "cleaning" in indoor environments. Conventional filters use increasingly finer mesh media to provide increasingly higher levels of effectiveness against small particles. A higher quality ASHRAE rated at 30% filter is approximately 94% effective at trapping particles of 5 microns or greater. For increased effectiveness against small particles, a polarized filter incorporates a charged media which can virtually attract particulate. The highest measure in particulate arrest is the HEPA filter. HEPA filters use an extremely fine mesh and are rated to be 99.97% effective at trapping particles of .3 microns or greater.
Now imagine a mechanism for indoor pathogen control that is not dependent upon a fine mesh trap with the resulting airflow restriction, but rather uses light energy to actively seek out and destroy pathogenic microorganisms wherever the light rays can penetrate. The particles are smaller than .1 micron, difficult to control with standard filters, are constantly monitored. When any particle containing RNA or DNA is exposed, (any living microbe), it is quickly destroyed. Perfect sealing of filter rack to prevent particle bypass is not required. The careful handling of filters which possibly contain active colonies of pathogenic microorganisms is also not required.