The world is interesting with air pollution currently. The sources of air pollution are more than one; the most main source considers the means of transportation, especially automobiles. Vehicles emit pollutants emission into air, such as carbon monoxide and carbon dioxide, hydrocarbons and nitrogen oxides. This research studies the influence of the air conditioning system on the engine performance, especially the emission of pollutants from the engine. Air conditioning system is a significant one of the loads that affect the engine performance characteristics, which increases the fuel consumption and thus increase the emission of pollutants into the surrounding environment. The study examines the influence of the different operating conditions on the air conditioning system and consequently on the performance characteristics of the engine and its emission of pollutants. The results of the research show the significant impact of the thermodynamic conditions of the vehicle carbine to enhance the performance characteristics of the vehicle engine and thereby reducing the emission of pollutants into the surrounding environment.