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Ozone Antimicrobial Efficacy
RTI INTERNATIONAL. Ozone Antimicrobial Efficacy. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-08/137, 2009.
Ozone is a potent germicide that has been used extensively for water purification. In Europe, 90 percent of the municipal water systems are treated with ozone, and in France, ozone has been used to treat drinking water since 1903. However, there is limited information on the biocidal activity of ozonated air as a treatment for contaminated surfaces. Understanding of the biocidal capability of ozone against the microorganisms primarily responsible for indoor air quality biocontaminant problems is still relatively limited. In a previous research project, we evaluated the biocidal efficacy of 3 to 10 ppm ozone on selected microorganisms in laboratory chamber studies. The objective here was to expand the early work by testing at much higher ozone levels. The goal of these experiments was to ascertain the effect of ozone against a vegetative bacterium, a bacterial spore, a yeast, and a fungal spore dried on the surfaces of glass microscope slides and pieces of gypsum wallboard. The target ozone levels were 100, 500, and 1000 ppm. Three exposure times, 1.5 hr, 6 hr, and 24 hr, were used. In addition, tests were performed at two levels of relative humidity.