Automobile exhaust systems are extremely hot. These high temperatures create the perfect environment to burn off excess hydrocarbons before they exit the tailpipe. However, exhaust gasses alone do not contain enough air to effectively burn excess hydrocarbons. Here’s where the air system comes in—when a pump introduces fresh air into the exhaust, it creates better conditions for hydrocarbons to burn. This process reduces the quantity of hydrocarbon emissions released into the air by cars and trucks.