Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmosphericpressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, timeresolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains are presented to stimulate critical discussions and collaborations in the future. 4 3.5 Optical absorption spectroscopy 3.5.1 Ozone 3.5.2 UV broadband absorption of OH density 3.5.3 Cavity ring-down spectroscopy 3.5 Selected non-optical techniques 3.5.1 Mass spectrometry 3.5.2 Flow visualization 3.5.3 Electron paramagnetic resonance spectroscopy 4. Temporal and spatial behaviour of key reactive species 4.1 Electron density (n e) 4.2 O atoms 4.2.1 Effect of admixture of O 2 /air on O concentration 4.2.2 Diffusion effect of shielding gas on O production 4.3 OH radical 4.3.1 Effect of H 2 O admixture on OH concentration 4.3.2 Effect of gas flow on OH concentration 4.3.3 Effect of O 2 on OH production 4.3.4 Effect of the treated samples on OH concentration 4.3.4.1 Effect of humidity of treatment sample on OH distribution 4.3.4.2 Effect of sample conductivity on OH distribution 4.3.4.3. Effect of the amplitude of the applied voltage on OH distribution 4.3.4.4. The effect of gas flow on OH distribution 4.3.4.5. The effect of the surface characteristics on OH distribution 4.3.5 Effe...

Summary: Low temperature, high pressure, non‐equilibrium plasmas are now routinely used in several material processing applications, and in some cases are competing with low pressure plasmas in areas where these have historically been dominant. Etching and deposition are examples of such applications. Amongst the novel applications of non‐equilibrium plasmas, biomedical applications such as electrosurgery, surface modification of biocompatible materials, and the sterilization of heat‐sensitive medical tools are particularly interesting. In this paper, first a brief overview of recent research on reduced‐pressure plasma‐based sterilization/decontamination methods is given. Then a detailed review and discussion on the effects of atmospheric pressure non‐equilibrium plasmas on the cells of bacteria is presented. This includes the evaluation of the inactivation kinetics and the roles of the various plasma agents in the inactivation process. Measurements of the plasma temperature, the UV emission, and concentrations of various reactive species for the case of air plasma are presented. Plasma sub‐lethal effects are also briefly discussed, and the prospects of the use of “cold” plasmas in the biomedical field are outlined. magnified image

Atmospheric-pressure non-equilibrium plasma jets (APNP-Js), which generate plasma in open space rather than in a confined discharge gap, have recently been a topic of great interest. In this paper, the development of APNP-Js will be reviewed. Firstly, the APNP-Js are grouped based on the type of gas used to ignite them and their characteristics are discussed in detail. Secondly, one of the most interesting phenomena of APNP-Js, the 'plasma bullet', is discussed and its behavior described. Thirdly, the very recent developments on the behavior of plasma jets when launched in a controlled environment and pressure are also introduced. This is followed by a discussion on the interaction between plasma jets. Finally, perspectives on APNP-J research are presented.

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