An investigation of the merits of ozone as an aerial disinfectant

Abstract

The question formulated in the introduction to this report can now be answered. Ozone in tolerable concentration is able to inactivate certain bacteria when these are present as unprotected singleton aerosol particles in atmospheres of 60–90% R.h. When such bacteria are covered with a protective coating of organic matter, however, as in aerosols naturally emitted during a sneeze or cough, then ozone in permissible concentration is without significant effect. Inactivation of such protected organisms can only be achieved by the use of ozone in decidedly higher concentrations, which must be deemed dangerous for prolonged spells of breathing. Bacteria that have settled on surfaces are generally more resistant to ozone than when in newly formed aerosols. Hence experimental evidence leads to the conclusion that ozone, in concentrations that can be breathed over long periods without irritation, cannot be expected to provide any effective protection against air-borne bacterial infection, through direct inactivation of the infectious carrier particles.