.3.4. The production of H2O2 To investigate whether variations in k0 (i.e., OH radical concentration) with A might account for some of the variation in kobs, the rate of H2O2 production was measured for gas discharge using different plate sizes. The rate of H2O2 production serves as a relative measure of the rate of OH radical production because H2O2 is formed by the recombination of OH radicals [21]: