Energetic solar protons are a natural source of ozone depletion due to nitric oxides they produce in the earth's atmosphere. In March 1989, following a period of intense solar activity, the TOMS instrument aboard the Nimbus 7 satellite recorded very similar ozone losses over both polar caps for areas extending from 90¿ to 70¿. Ozone depletions of 7.4¿109 kg for the south polar cap and 8.0¿109 kg for the north polar cap indicate the degree of symmetry over the polar caps. ¿ American Geophysical Union 1992