To strengthen National Expressway No.5 in the 96 years since Nov. 15 opening bus access, mobile sources of pollution are likely to cause pollution emissions from diesel vehicles, Department of Environmental Protection, Yilan County Government control the diesel for moving in the Syueshan tunnel , National Expressway No.5, and an elevated section along the plains, as well as importand country road. Furthermore, Department of Environmental Protection, Yilan County Government also continued to monitor the Syueshan tunnel air pollutants, and to support the expansion of promoting anti-idling engine to stop operations of diesel vehicles to reach the overall effectiveness of control, to maintain good Yilan County, mountain, water and air of good living environment.

diesel , Syueshan tunnel , roadside-inspection