In an effort to improve the air quality in Taoyuan County and offer the citizens a clean and fresh living environment. In this year Taoyuan County Government Environmental Protection Bureau also in accordance with the objectives and spirits of “Air Pollution Control Act”, in the diesel car pollution aspect via irregular emission inspection affair to effectively improve air quality conditions in Taoyuan County, to reach the effectiveness of pollution reduction and environmental protection. The motor vehicles with diesel engine within the Taoyuan County area were targeted in this project., Through the approaches of citizens’ violation reporting and judgment by visual determination of smoke, motor vehicles with diesel engine were notified to report to the station for testing, as for the sampling inspection of fuel product, the methods of in-station fuel sampling and block-to-test on the roadside were carried out for the purpose of controlling the illegal fuel in possession of excessive sulfur content. According to the contract, the execution period of this project was from July 8, 2009 to March 7, 2010. There are 4 major items in this project, including inspection notifying of the diesel vehicle, the diesel vehicles block-to-test on the roadside, the diesel vehicles inspection on the location, the oil ingredients spot check and management, to handle citizens’ violation reporting, the diesel vehicles to examine the system impetus, to hold a meeting of initiative guidance and self-management meeting, two numbers of consultations across bureaus and a number of expert consultation meeting, to establish internet query system about the pictures of visual judgment, and the statistical analysis of vehicle inspection results, etc.