Electrical discharges involving the formation of NO, NO₂, HNO₃, and O₃

Abstract

Laboratory discharge experiments were performed with a Wimshurst electrostatic generator with discharge energies between 0.005 and 0.1 J in air, in an atmosphere of various O 2 /Ar ratios, and an atmosphere of various O 2 /N 2 ratios in order to determine relative NO, NO 2 , HNO 3 , and O 3 production from a discharge. The results in air showed that the NO/NO x (NO x = NO + NO 2 ) ratio varied between 0.75 and 0.95, depending on the discharge energies, that little O 3 was produced except at very low discharge energies, and that no HNO 3 was produced when the air was humidified. The results in an O 2 /Ar atmosphere showed that O 3 production increased with decreasing O 2 content of the atmosphere, that its production was kinetically controlled, and that its production probably takes place in the cooler regions of the discharge. In an atmosphere of various O 2 /N 2 ratios the production of NO x was also seen to be kinetically controlled and was observed to reach a maximum when the O 2 was 30–40%, although its production, unlike O 3 , probably takes place in the hot regions of the discharge and results from an ohmic heated channel.