Peroxynitrite is an important chemical in the human immune system, which has high biocidal activity and can resist the invasion of pathogens. Currently, in vitro generation of peroxynitrite faces major technological challenges, especially for gas‐phase production, which requires low‐pressure conditions. Here, we report the method of how to generate gas‐phase peroxynitrite at atmospheric pressure using dielectric barrier discharge. Results show that the peroxynitrite concentration positively correlates with energy density. Moreover, Penicillium digitatum, a common fungus contaminant greatly affecting food and fruit preservation, was used as a microbial pathogen model to confirm the biocidal effects of ozone‐free nitrogen oxides under different discharge conditions. The germination inhibition efficiency of P. digitatum is highly likely attributed to the synergistic effect of gaseous peroxynitrite and NO.

Two modes of the atmospheric-pressure plasma discharge, distinguished by the dominant O3 and NO x species are studied numerically and experimentally. To investigate the mode transition mechanisms, here we develop a global chemical kinetics model for the atmospheric-pressure dielectric barrier discharge involving 63 species and 750 reactions. Validated by the experimental results, the model accurately describes the mode transition. The N, O, O2(a), and O2(b) are the essential transient intermediate species for the O3 and NO x production and loss reactions.The individual and synergistic effects of the specific discharge energy and the gas temperature on the species density and the relative contributions of the dominant reactions are quantified under the increasing discharge voltage conditions. The modeling results indicate that the gas temperature and specific discharge energy both contributed to the discharge mode transition, while the decisive factors affecting the change of the O3 and NO x density are different in the respective modes. These insights contribute to diverse plasma applications in biomedicine, agriculture, food, and other fields where selective and controlled production of O3 and NO x species is the key for the desired plasma performance.