Evaluation of the roles of reactive species, heat, and UV radiation in the inactivation of bacterial cells by air plasmas at atmospheric pressure

Recently. non-equilibrium. atmospheric pressure air plasmas have been shown to possess excellent germicidal properties. A number of studies have shown that air plasmas are capable of inactivating a wide range of microorganisms in the matter of few seconds to few minutes. However. until now little information regarding quantitative measurements of the various plasma agents that can potentially participate in the inactivation process has been published. In this paper, emission spectroscopy and gas detection are used to evaluate important plasma inactivation factors such as UV radiation and reactive species. Our measurements show that for non-equilibrium, atmospheric pressure air plasmas. it is the oxygen-based and nitrogen-based reactive species that play the most important role in the inactivation process. (C) 2004 Elsevier B.V. All rights reserved.