Trends in total atmospheric ozone from 1979-1989 were analyzed to derive the corresponding changes in the tropospheric photodissociation rate coefficient J1 for the reaction O3+h&ngr; (&lgr;<330 nm)→O2+O(1D). Zonally and annually integrated trends in J1 are +3.8¿2.9% per decade in the Northern hemisphere and +4.1¿2.7% per decade in the Southern hemisphere. Changes in [OH> due to the J1 trends may have contributed to the slowing of atmospheric methane increases observed in recent years. ¿ American Geophysical Union 1992