Changhua County has been a city of industrial and agricultural development for a long time. The primary source of air pollution in this county is the waste gases emitted from diverse types of factory and variety of motor vehicles; and in the wake of the change from the pattern of urban land utilization along with the promotion of populace’s awareness of environmental protection, the total number of factory has been decreasing year by year; contrarily, the total number of motor vehicle in use has been increasing year after year that makes the emission of exhaust gas from motor vehicles the most critical source of urban air pollution. Therefore, how to reduce the emission of exhaust gas from motor vehicles has become the extremely important issue of environmental protection for Changhua County. In the aspect of controlling the diesel vehicles, 6,538 vehicles inspected ＆ tested thereof smoke emission while 135 vehicles therein failed to pass the inspection at a nonconformity rate of 2.1%. With regard to the oil sampling, 12 diesel oil samples therein were screened and submitted for inspection. Vehicles failed to pass the visual determination and followed an inquiry of registration data, screening and report for scrapping, handing in for cancellation, suspension of driving, etc. factors; totally 1,349 letters of notice for inspection & test works were dispatched. 10 new companies were promoted to participate in the self-management of diesel vehicles, 4,802 diesel vehicles participated in the self-management, and 2,384 diesel vehicles were replaced.This project, by executing variety of vehicular control measures together with cooperation cross the bureaus and divisions plus a propagation to the populace; Changhua County has achieved a practical effect and a complete performance to improve the air quality.

Particulate matters, Mobile source, Visual determination