Bombardment of the earth's atmosphere by charged particles produces odd nitrogen and odd hydrogen. These species take part in catalytic reactions which destroy atmospheric ozone. We present model studies of the effects of the August 1972 solar proton event on stratospheric ozone. Calculated ozone depletions following the event are in very good agreement with observations using presently accepted chemistry, especially between 30 and 45 km. The influence of chlorine chemistry on model simulations of this event is examined. The calculated decreases in ozone are expected to yield temperature decreases, since solar heating in this region strongly depends on ozone. Consequently, the temperature dependent reaction rate constants are affected, and we show that the inclusion of temperature feedback influences the calculations of the effect from about 42 to 55 km.