Comparison between He/O2 and He/H2O atmospheric pressure cold plasmas

Atmospheric-pressure He/O₂ and He/H₂O plasmas have received growing attention in recent years, for they are easy to be kept cold and diffusive as well as capable of efficiently generating reactive radicals like O and OH. In this contribution we present the results of a comparative study of the chemistry of these two kinds of plasmas and their suitability for biomedical applications. An extensive literature review has been performed to create detailed up-to-date chemistry models of these He/O₂ and He/ H₂O discharges. In this study the concentration of O₂ and H₂O are kept below 1% as this is the regime preferred in most practical scenarios. Higher concentration of O₂ (or H₂O) leads to unstable and hotter discharges with lower concentration of relevant reactive species.