The chemical behavior of hydrogen sulfide, carbonyl sulfide, carbon sulfide, methanethiol, ethanethiol, methyl sulfide, ethylsulfide, methyl-disulfide, ethyldisulfide, methylethylsulfide, thiophene, 2-methylthiophene, 3-methylthiophene, 2,5-dimethyl-thiophene and propene (used as a control) was investigated under atmospheric conditions in outdoor smog chambers. Target initial concentrations of 2.0 ppm carbon of a test compound and 0.1, 0.2, 0.5 and 1.0 ppm NOx were investigated simultaneously in four identical smog chambers. A total of twenty 2-day four-chamber runs, or eighty 2-day experiments involving irradiated sulfur species-NOx or propene-NOx systems was conducted. The results of experiments conducted with each compound were analyzed by examining the influence of initial conditions on the following selected reaction parameters: the time to NO-NO2 crossover; maximum concentration of O3, NO2, PAN, SO2, particulate, and condensation nuclei; nitrogen mass balance; time to one-half consumption of the test species; and second-day net ozone concentration. Subsequently, selected reaction parameters were compared across test compounds.