Mixtures of aniline/ethylene/NOxwere photoiyzed in a 22.7‐m3Teflon reaction chamber operated in a dynamic mode. Several minor products, including nitrobenzene, azobenzene, α‐nitroaniline, phenol, and benzoic acid, were identified. The production of aerosol was also observed. The product mixtures were exposed toSalmonella typhimuriumstrains TA98 and TA100 both with and without metabolic activation. Exposures of the gas mixture alone and the aerosol plus gas mixture were performed. In addition, filters of the aerosol were collected, extracted, and used in a plate incorporation procedure with these strains. The results show the gas phase products from the irradiated mixture to be relatively nonmutagenic in TA98 and TA100. This same result was found in the aerosol exposure, although the deposition into the media may have been low. However, extracts from the aerosol when directly incorporated into the medium show mutagenic activity for TA98.