As a new approach to treat acute respiratory distress syndrome

NO has recently received more attention

which may be generated by arc discharge in air. The concentration of NO2 and the ratio of NO2 /（NOx）must be as little as possible for the medical application of NO. In this paper

NO is generated by negative pulsed discharge between needle and plate electrodes in dry air at the atmospheric pressure. Some important parameters affecting concentration of NO and NO2 have been investigated. These include the distance between electrodes

the pulsed discharge frequency and electrode polarity. The results show that the ratio of NO2 /（NOx） is the lowest within one of the distances between electrodes and the concentration of NO and NO2 increases with raising of frequency and increasing of the distance between electrodes. Electrode polarity unconspicuously affects the ratio of NO2 /NOx. The concentrations of NO2 and the ratio of NO2 /（NOx） could be decreased by the choosing and combination of discharge conditions.