Since 2009, the Taiwan Environment Protection Agency had provide help with Taoyuan Environment Protection Bureau analyzed the Continuous Emission Monitoring Systems (CEMS) data offered from the factories with cogeneration process, and found some artificial data, which are proved by inspection operations and the help of the judiciary. In the process of pursuing the air pollution fee is a challenge due to the identification of fraud duration. After analyzing and comparing more than 5 million data in detail, we succeed in getting 659.6 million fines for 5 years limitation of prosecution and break the record of payment in air pollution fee. The present work mentioned that the data of the CEMS analyzer during the audit process are lower in comparison with the data transported to the Taoyuan Environment Protection Bureau. The Taoyuan Environment Protection Bureau developed the parallel-comparison- data system with Cylinder Gas Audit (CGA) will be able to prevent the events of fraud data in the future, and make CEMS as a useful tool in monitoring and controlling the emission of air pollution.