The subthreshold self-non-self-sustained discharge in air was studied as the basis of the system for cleaning urban air from ecologically harmful admixtures. A cycle of experiments was carried out and the efficiency of the destruction of small amounts of hydrogen sulfide mixed with air (about 8 ppm) introduced into the processed air volume was determined. Experiments demonstrated a relatively high degree of H2S decomposition (its concentration decreased 41.5 times at unit energy deposition of 8 J/cm(3) in the SNSS discharge).

A subthreshold microwave discharge in atmospheric-pressure air is used to process mixtures of mercaptans (thiols) with air and with air and methane. It is found that, at microwave intensities of ~10 kW/cm2 and pulse durations of 1–3 ms, the mercaptan concentration decreases 100-fold in mixtures with air and 20-fold in mixtures with air and methane. It is shown that, at an average specific energy deposition in a single discharge of ~0.4 J/cm3, the specific microwave energy spent on mercaptan decomposition is ~10 J/cm3. It is concluded that the active zone of the discharge with high specific energy deposition occupies less than 5% of the microwave beam volume.