Ozone is well known as a disinfectant in the liquid phase as it is widely used for water treatment applications. Ozone has
also been shown to be an effective disinfection agent for surfaces in the gas phase. Work done by the USEPA
(Menetrez, M. Y., Foarde, K. K., Schwartz, T. D., Dean, T. R. and Betancourt, D. A.(2009)'An Evaluation of the
Antimicrobial Effects of Gas-Phase Ozone',Ozone: Science & Engineering,31:4,316 — 325) provides information
on the log reduction for various micro organisms as a function of CT and relative humidity (RH). CT is a measurement of
the ozone concentration in ppm (mg/l) multiplied by the exposure time in minutes, i.e. mg-minute/liter. The results of the
study on glass slides is presented below.