Among all developed countries around the world, owing to rapid economic development, the number of motor vehicle in use also grows up rapidly, which crowds roads and pollutes air. As a result, in regard to gasoline ＆ diesel vehicle control among every developed country, United States is the most active one in promoting that. The States not just develop many techniques to control mobile pollution source, but also promote regular inspection and maintenance system actively. Concerning their control system, except the harsher and harsher assurance standard to new vehicle, in terms of controlling in-use vehicle (old vehicle control), they fully implement regular inspection and maintenance system for in-use vehicle to improve air quality in urban areas and to maintain public health, too. Taoyuang county is industrial and commercial center with a number of diesel vehicles and relatively serious air pollution; therefore, to cooperate with EPA’s emission control strategy for diesel vehicles, aiming at achieving objectives in “Air Pollution Control Act” from the main pollution source, diesel vehicle. Based on its current using situation, the act rules regular inspection control and maintenance to enhance air pollution in Taoyuang county effectively and to achieve environmental protection. Thus, the project plans to focus on diesel vehicle in Taoyuang county, informing diesel vehicles in jurisdiction to do inspection by judging their emissions visually or by accepting reports from the public.

Visual determination, Mobile source, Particulate matters, Gaseous pollutant