Ozone been applied on a large scale to heating, ventilating, and air conditioning (HVAC) systems. Major reasons for this surge of interest in ozone treatment of indoor air include:
The large majority of projects so far are for gaming facilities (casinos, bingo halls, card rooms) and larger hospitality businesses including restaurants, showrooms, and bowling centers. These users have found that there is a high return on investment in systems which create and maintain high air quality. Many projects, often much smaller in scale, have been completed for cocktail lounges, taverns, airport smoking areas, and even for advanced technology facilities for animal raising on a large commercial scale.
The major objection to ozone is safety. Its concentration in public areas must be kept below harmful levels. This is accomplished by new technology ozone generation and monitoring equipment combined as a self-controlling system. There is disagreement among cognizant agencies about what are safe levels and suitable guidelines for ozone concentrations. The US FDA states a limit of .05 ppm for areas where people of all kinds congregate. Most ozonated HVAC systems with automatic controls are programmed not to exceed concentrations ranging from 0.03 to 0.05 ppm. These concentrations are below naturally occurring outdoor levels in many regions, but are just high enough to reduce VOCs significantly. Furthermore, the ozone concentrations are much higher in the supply ducts where bacteria, mold, mildew, and VOCs accumulate. For ozone injected into HVAC systems it is absolutely necessary to include ozone sensors to automatically control the ozone concentration in areas where the public congregate.
Two applications of ozone in the “hospitality industry” air quality control are:
After operation of the system for about one year, the preliminary findings were: