Jovian photochemistry above 1000 Å appears to consist of four zones: 1) photolysis of methane at 1216 Å and a total pressure of less than 10−5 atm; 2) photolysis of ammonia at 1700–2200 Å and a total pressure of less than 5×10−4 atm; 3) photolysis of both methane and ammonia at 1350–1450 Å at a total pressure of about 10−4 atm; and 4) photolysis of ammonia at 1450–1700 Å at a total pressure <10−2 atm. No photolysis occurs below this level. The large excess of hydrogen suggests that all radicals ultimately react with hydrogen, the net result being the production of H atoms. It is concluded that complex C-H-N molecules are not formed in Jovian photochemistry at wavelengths >1000 Å because of the reducing atmosphere. Methane and ammonia persist in the atmosphere because photochemical mechanisms for their destruction ultimately results in their reformation by reaction of such species as CH2, NH and NH2 with H2.