The atmospheric chemistry of 2-methyl-1-nitronaphthalene and the photolysis of 3- nitrobiphenyl have been investigated. Under atmospheric conditions, photolysis was the dominant loss process for 2-methyl-1-nitronaphthalene, while no photolysis of 3- nitrobiphenyl was observed. These data have been used, together with our previous data concerning the atmospheric reactions of 1-and 2-nitronaphthalene and the formation of nitroarenes from the gas-phase atmospheric reactions of the 2- to 4-ring PAH, to predict ambient nitroarene concentrations. The predicted concentrations of the nitronaphthalenes, 3-nitrobiphenyl, 2-nitrofluoranthene and 2-nitropyrene are compared with ambient air data from Torrance and Glendora, CA, USA.