The explanation of the formation and existence of nitrogen dioxide (NO2) at ambient temperature is important towards the basic understanding of the nature of chemical reactions of the pollutants in the atmosphere and to the visibility of the atmosphere. The objectives of the present studies are to highlight the detailed effect of ambient temperature on the conversion of nitric oxide (NO) to NO2 in the presence of ozone (O-3) gas with varying concentrations of other species viz., N-2, CO2, CO, H2O, O-2, etc. It is found that O-3 is the only chemical species active up to its last concentration involved in the conversion of NO into NO2 at ambient temperature.