Unburned hydrocarbons are highly toxic and they contribute to the formation of ozone at the ground level which causes coughing, choking, irritation in the respiratory system and reduced lung capacity. The nitrogen in the fuel burns at high temperature and pressure in the presence of oxygen from air and turns into various oxides of nitrogen which are very strong irritants for lungs and also weaken the immune system against respiratory infections. Carbon monoxide blocks the transport of oxygen to the brain, heart and other vital organs of the body. It has a strong affinity for hemoglobin found in the blood and readily reacts with it, thus preventing the oxygen to bind with hemoglobin (Rao, 1989).