Rate constants have been measured as a function of kinetic energy for three exothermic reactions: reaction (1), H2O2++NO→NO++H2O2; reaction (2), H2O2++H2O→H3O++HO2; and reaction (3), O2++H2O2→H2O2++O2. The rate constants are all large at 300¿K and are insensitive to relative kinetic energy up to approximately 1 eV. Reaction (3) is believed to be the dominant source of H2O2+ in the D region, and reaction (2) is believed to be the dominant loss. The near equality of &kgr;2 and &kgr;3 implies that the steady state ratio of [H2O2+>/[O2+> is approximately equal to [H2O2>/[H2O>. However, the ratio [H2O2>/[H2O> in current model atmospheres is very much less than the reported 34+/32+ ion concentration ratios in the D region.