Mobile pollution sources are one of the leading factors in metropolitan air quality. In order to further perfect mobile pollution source control operations, the Environmental Protection Department of New Taipei City has established the New Taipei City Motorcycle/Motorscooter Pollution Source Audit and Control Program (2019), which was contracted to Envimac Technology and Consultants Corporation. All tasks of the program, as calculated from January 1, 2019 to November 30, 2019, have reached 100.0% implementation status. The work results from the plan are thus summarized and explained below: In the course of the audit and control operations, a total of 3,016 vehicles underwent inspection. Of these, 244 two-stroke motorcycles, including 195 were registered in New Taipei City and 49 were registered in other counties. The unqualified rate was 44.7%. A total of 2,772 four-stroke motorcycles, including 2,360 were registered in New Taipei City and 412 were registered in other counties. The unqualified rate was 16.9%. Subsequent ruling operations have been carried out in accordance with relevant regulations. A total of 654,219 license plates were identified, among which there were 491,966 vehicles registered in New Taipei City, for 75.2% of the total. Of 95,063 vehicles subjected to unscheduled testing, 76,748 were registered in New Taipei City. The priority of punishment were two-stroke motorcycles and four-stroke motorcycles of 25 years without periodic inspection which were identified by vehicle plate recognition system. Subsequent ruling operations have been carried out according to the month of the vehicle license. The service of mobile motorcycle exhaust inspection station in remote areas has been completed 66 times, a total of 1,229 motorcycles. According to the analysis of traffic volume, the traffic volume of small personal passenger vehicles in several sections of New Taipei City in 2018 was higher than in 2017. On the contrary, the traffic volume of other vehicles was not significantly increased or decreased. The 2018-year traffic volume was used to estimate the transportation-mode TRTS-4S；it allocated the TEDS10.0 air pollution emission factor to calculate traffic pollutant. The top three traffic emissions are CO, NOX, and THC. Four-stroke motorcycles/motor scooters and small personal gasoline-powered passenger vehicles are the significant contributions of CO and THC, while large diesel-powered cargo vehicles and small personal gasoline-powered passenger vehicles are the major contributions of NOX. The comparison of high-pollution motorcycle/motor scooter data shows that between January and October of 2019 more than 50% highly polluted motorcycle/motor scooter showed only once per month. Meanwhile, it shows only 4.3% of vehicles that appeared each month in ten months. Due to the monthly pass, 365,532,152 passenger kilometers were transferred from small passenger vehicles and motorcycles/motor scooters to public transportation from April to December in 2018. Assume that the odd-even license plate system implements in New Banqiao Station Special Zone and that it will reduce 50% of the small passenger vehicles traffic volume and 9%~26% air pollution in this area, especially lead (Pb) pollution.