In this study, Ar– \(\:{\text{N}}_{2}\text{O}\) discharges sustained by a surfatron device operated at atmospheric pressure were investigated to elucidate their physicochemical behavior and potential for reactive oxygen and nitrogen species (RONS) generation through \(\:{\text{N}}_{2}\text{O}\) decomposition. The addition of \(\:{\text{N}}_{2}\text{O}\) to an argon plasma led to a shortening of the plasma column and the appearance of a diffuse afterglow region that extends to long distances (> 50 cm). Increasing \(\:{\text{N}}_{2}\text{O}\) concentration results in suppression of the discharge filamentation, as well as to an increase in gas temperature, that exceeds 3000 K above 1.5% \(\:{\text{N}}_{2}\text{O}\) . Spectroscopic and thermometric analyses confirmed effective \(\:{\text{N}}_{2}\text{O}\) dissociation and the formation of RONS in the discharge. The afterglow, characterized by long-lived metastables and excited argon, nitrogen, and oxygen species, exhibited progressively decreasing temperatures, reaching below 100 °C. Optical emission analysis in this zone revealed rich \(\:\text{A}\text{r}\) , \(\:\text{N}\) , \(\:\text{O}\) , \(\:\text{N}\text{O}\) , \(\:\text{O}\text{H}\) , and \(\:\text{N}\text{H}\) spectra, from which dissociation pathways and kinetic mechanisms have been proposed. A simplified kinetics scheme to elucidate the behavior of these plasmas is proposed, and the results are compared to those obtained with Ar– \(\:{\text{N}}_{2}\) plasmas and postdischarges. In addition, mass spectrometry suggests \(\:{\text{N}}_{2}\text{O}\) decomposition preferentially takes place through nitrogen-oxygen bond breaking, yielding \(\:{\text{N}}_{2}\) , \(\:{\text{O}}_{2}\) , and \(\:{\text{N}\text{O}}_{\text{x}}\) products at the gas exhaust.
