The National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, Michigan, tests Class 8 truck emissions. The facility will run several tests to set new emissions rules for commercial vehicles.
Photo courtesy of U.S. Evnironmental Protection Agency

The U.S. Environmental Protection Agency (EPA) has begun setting rules that would limit nitrogen oxide (NOx) emissions from commercial trucks – primarily from diesel-burning vehicles.

EPA Administrator Andrew Wheeler says the rules being developed “will modernize heavy-duty truck engines, improving their efficiency and reducing their emissions, which will lead to a healthier environment. The U.S. has made major reductions in NOx emissions, but through this initiative we will continue to reduce emissions, while spurring innovative new technologies, ensuring heavy-duty trucks are clean, and remain a competitive method of transportation.”

NOx emissions cause respiratory problems, most notably asthma. And, nitrogen oxides can react with other environmental chemicals to create ground-level ozone, another pollutant that can cause respiratory problems. In the environment, NOx reacts with water and oxygen to form acid rain, nitrate particles in NOx cause smog, and excess nitrogen from NOx in the water can lead to algae blooms. From 2007 to 2017, regulations on power plant emissions caused NOx emissions to fall 40%, but vehicular emissions haven’t fallen as quickly.

Wheeler announced plans in late 2018 to launch the EPA’s Clean Trucks Initiative (CTI) to set new emissions rules, and the January announcement formalizes the start of that process. The notice lists general goals, studies the agency hopes to conduct, and promising technologies that could improve emissions. It doesn’t, however, spell out new standards, something agency officials say they hope to do in 2021 after hearing public comments from state regulators, industry groups, environmental advocates, healthcare professions, and citizens. One goal is to have a single national standard for trucks, avoiding the problems that light-duty vehicles have in meeting California standards that are more stringent than national ones. Another issue is the expected lifespan of commercial diesel engines. Regulators have found that truck fleets use engines far longer than projections assumed, so new technologies that could reduce emissions must be evaluated longer.

Other goals include:

  • Lowering NOx emission standards
  • Improving test procedures, test cycles to ensure real-world emission reductions
  • Updating certification, in-use testing protocols
  • Lengthening mandatory emissions-related component warranties
  • Possibly lengthening regulatory useful life, reflecting actual in-use activity
  • Potentially regulating engine rebuilding
  • Offering incentives to encourage transition to current-, next- generation cleaner technologies