To study the efficiency of the removal of vapors of volatile organic compounds from air flows when processed by a plasma of pulsed discharges, a method of competing reactions is proposed. Using a compound with known parameters in the model mixture, it is possible to estimate similar parameters of other compounds using a chromatographic method of analysis that does not have a high temporal resolution. By the example of styrene and methyl methacrylate vapors, it was shown that for unsaturated compounds their relative reactivity in the discharge plasma correlates well with the ratio of the rate constants of their reactions with ozone.