Obtaining high yields in agricultural production is essential due to the world's population growth and increased food demand. At the same time, adverse effects of agriculture on the environment need to be kept to a minimum. Low temperature plasmas (LTPs) show promise as efficient green technologies for enhancing productivity while maintaining good food quality and safety in the many steps of the food cycle. As a result, applications of LTPs in agriculture have led to creation of a new, rapidly developing field called “plasma agriculture.” Here, we briefly overview the state‐of‐the‐art of LTP applications in the complete food cycle, that is, in treatments of seeds, plants, and food.

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Plasma medicine means the application of non-equilibrium plasmas at temperatures around body temperature, for therapeutic purposes. Non-equilibrium plasmas are weakly ionized gases, which contain charged and neutral species and electric fields and emit radiation particularly in the visible and ultraviolet range. Medically relevant cold atmospheric pressure plasma (CAP) sources and devices are usually dielectric barrier discharges (DBDs) and non-equilibrium atmospheric pressure plasma jets (N-APPJs). Plasma diagnostic methods and modelling approaches are used to characterize the densities and fluxes of active plasma species and its interaction with surrounding matter. Distinguished from direct application of plasma on living tissue, treatment of liquids like water or physiological saline by a CAP source is realized to acquire specific biological activities. Basic understanding of plasma interaction with liquids and bio-interfaces is essential to follow biological plasma effects. Charged species, metastable species, and other atomic and molecular reactive species first produced in the main plasma ignition are transported to the discharge afterglow to finally be exposed to the biological targets. By contact with these liquid-dominated bio-interfaces, other secondary reactive oxygen and nitrogen species (ROS, RNS) are generated. Both ROS and RNS possess strong oxidative properties and can trigger redox-related signalling pathways in cells and tissue leading to various impacts of therapeutic relevance. Dependent on the intensity of plasma exposure, redox balance in cells can be influenced in a way that oxidative eustress leads to stimulation of cellular processes or oxidative distress leads to cell death. Currently, clinical CAP application is realized mainly in wound healing. Plasma in cancer treatment (i.e. plasma oncology) is the currently emerging field of research. Future perspectives and challenges in plasma medicine are mainly directed to control and optimize CAP devices, to broaden and establish its medical applications, and to open new plasma-based therapies in medicine.

One of the major concerns in the COVID-19 pandemic is related to the possible transmission in poorly ventilated spaces of SARS-CoV-2 through aerosol microdroplets, which can remain in the air for long periods of time and be transmitted to others over distances >1 m. Cold atmospheric pressure plasmas can represent a promising solution, thanks to their ability in producing a blend of many reactive species, which can inactivate the airborne aerosolized microorganisms. In this study, a dielectric barrier discharge plasma source is used to directly inactivate suitably produced bioaerosols containing Staphylococcus epidermidis or purified SARS-CoV-2 RNA flowing through it. Results show that for low residence times (<0.2 s) in the plasma region a 3.7 log R on bacterial bioaerosol and degradation of viral RNA can be achieved. K E Y W O R D S bioaerosol, cold plasma, inactivation, indoor airborne transmission, SARS-CoV-2 Alina Bisag and Pasquale Isabelli contributed equally to this study.

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This work is focused on the use of non-thermal plasma to improve the electrospinnability of poly(L-lactic acid) (PLLA). The use of toxic high boiling point solvents is minimized to produce high quality solvent free nanofibrous scaffolds for biomedical applications. PLLA polymeric solutions dissolved in pure dichloromethane are exposed to the plasma plume of a jet developed by some of the authors and driven by high voltage pulses with rise rate of several kV ns À1 . The effects of peak voltage, pulse repetition frequency, volume of the solution and treatment time on the morphology of electrospun fibers are investigated by means of scanning electron microscope. Electrospinning is performed at different time lapses after the plasma treatment to study the durability of the induced effects. Figure 10. Spatially resolved optical emission spectrum of the plasma jet, operating conditions: PV ¼ 20 kV, PRF ¼ 330 Hz, Ar flow rate ¼ 1 slpm. V. Colombo et al.