[Emission Reduction Benefits When Eliminating Yellow-label Vehicles in the Jing-jin-ji Region].

In order to evaluate policy implementation for yellow-label vehicles (namely, those that fail to meet the Chinese No.1 standard for exhaust emissions), and to compare the policy of an early elimination subsidy with traffic restrictions of these vehicles, the emission factor method was adopted to calculate the emission reduction resulting from the two policies in the Jing-jin-ji Region. The results showed that: ① The policies led to good emission reductions for the Jing-jin-ji Region. Since the implementation of the policies, the cumulative reductions of CO, HC, NO, PM, and PM have been 5003.2 kt, 397.9 kt, 318.2 kt, 9.6 kt, and 10.6 kt, respectively. ② The pollutants reduced most prominently were CO, HC, and NO, which contributed greatly to the emission reductions and air pollution control. ③ The main motorcycle types for the CO and HC emission reductions were small gasoline-powered passenger vehicles and light duty gasoline-powered vehicles. Heavy duty diesel cars contributed the most to the emission reduction of NO and particulate matters. ④ The emission reductions for CO, HC, and NO were greater in densely populated urban areas in the Jing-jin-ji Region. The emission reductions of CO and HC in Beijing, Tianjin, and Shijiazhuang were more obvious than in other cities, and the emission reductions of NO and particulate matters were more obvious in Tianjin, Shijiazhuang, Tangshan, and Handan. ⑤ Comparing the two policies of an early elimination subsidy and traffic restriction, the emission reduction of the former policy is continuous for a few years, and the effectiveness of reduction is significant in several years. However, the effectiveness of the latter policy decreases with time.