The levels of emissions of gaseous pollutants from indoor fires within the conventional apartment types in Benin City have been studied. In Nigeria indoor smokes from domestic activities and mosquito coils occur in a significant number of houses. This study was conducted using carbon monoxide as a tracer gas within smoke in households over Benin City. Measurements were conducted using the most common residential building-type (flats) in the region. Sampling was done at 0.1m AGL, 1.0m AGL, 2.0m AGL and ceiling height to ascertain vertical distribution. The study indicated that huge levels of CO ranging between 25 and 40 ppm were observed in the self-contained or bachelor’s flat with windows closed during the night for guard against mosquitoes and crawling insects, while similar apartments with windows opened during the night equipped with protective mosquito nets showed CO concentrations with levels of between 28 and 42 ppm. The results of both house-types were significant when compared with values of the World Health Organization (WHO) and Federal ministry of environment (FMENV) acceptable limits for indoor CO concentrations.