A relatively small, but intensively used fleet of Non-Road Mobile Machines (NRMM) produces particulate mass exhaust emissions comparable to those of the much larger Dutch road‑vehicle fleet. For NOₓ, road traffic still emits more overall, but the difference is narrowing.

In this light, on behalf of the Dutch Ministry of Infrastructure and Water Management, TNO carried out a study to identify the required improvements for future NRMM emission standards. An important part of the research was the assessment of real-world emissions of NRMM.

The results of this study show that current Stage V emission requirements leave substantial room for improvement. Improvements necessary to upgrade NRMM emission standards from Stage V towards a potential Stage VI include:

  1. Removing differences in NOₓ- and PM/PN limits between engine power classes, and introducing a limit for NH₃;
  2. Ensuring that low‑load operating conditions are adequately covered in the test procedure;
  3. Introducing in‑use emission performance monitoring and checking, including anti-manipulation provisions.