Consultant report

Managing emissions from non-road vehicles

Non-road vehicles, mainly agricultural and construction equipment, are a key source of pollution in many countries and regions: In the United States, they account for almost three quarters of the fine particulate matter (PM2.5) and one quarter of the nitrogen oxides (NOX) emitted from mobile sources. In Europe, non-road vehicles contribute approximately one quarter of the PM2.5 and more than 15% of the NOx emitted from mobile sources. This is mostly because the emission-control strategy for non-road vehicles, including tailpipe emission standards and in-use compliance, lags years behind that of heavy-duty vehicles, although the vehicles share many similarities in the design of diesel engines and exhaust emission control technologies. As a result of the quickly expanding market and better control of emissions for on-road vehicles, non-road vehicles will soon become the dominant source of air pollution in the world.

A comprehensive strategy is required to control emissions from both new and in-use non-road vehicles. Many countries have gradually tightened emission standards for new non-road vehicles, forcing implementation of advanced emission-control technologies on non-road vehicles as those technologies are successfully adopted on heavy-duty vehicles. But this is far from enough—there are still few requirements or regulatory programs in place that impact the emissions of the in-use fleet of non-road vehicles. Regulation of the in-use fleet, including a registration system and emission compliance programs, is essential for tracking the ownership, usage, and status of non-road vehicles and emission-control systems. In addition, regulatory compliance programs can serve to monitor emissions from vehicles to ensure that they comply with the required standards throughout the regulated useful life of the vehicles.

The United States and certain countries in Europe have begun to manage in-use non-road diesel equipment, which can provide insight on the issue. This report provides an overview of those regulation programs in two parts. The first part offers examples of registration or labeling systems for non-road equipment adopted in the State of California, London, England, and Hong Kong. The second part focuses on advanced non-road diesel compliance programs designed by the U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB). The report further compares the compliance tools for non-road vehicles with those for heavy-duty vehicles.

Staff contact: Zhenying Shao

Fleets Zero-emission vehicles
Clean air Off-road
Emissions control