It is quite usual and normal for cars to produce emissions when the engine is running. The usual products to be emitted from a car include water vapor, nitrogen gas and carbon dioxide. Several problems can however cause abnormal levels of emissions, which will seek one to seek for local car emissions repair. Fuel or gas is burned off inside the car engine along with oxygen to enable the car generate power. There are several car emission repair steps that can be taken to resolve emission related problems. The car contains a number of emission control systems to help keep the level of pollutants discharged into the atmosphere in check. One of such cleaning systems is known as the air filter. It is recommended that the air filter is checked periodically to ensure that filter is not clogged with dust, dirt and other particles. It is also important to replace air filters after every year of use.