EPA Tightens Heavy-duty Emissions Caps


EPA Tightens Heavy-duty Emissions Caps
A heavy truck leaves a trail of exhaust fumes in its wake. © Victor Yarmolyuk

United States President Joe Biden’s administration published a final rule last week tightening caps on heavy-duty truck emissions of nitrous oxides.

Adopted by the Environmental Protection Agency, the new regulations take effect in 2027 and focus on human health because NOx helps generate ozone, which causes and exacerbates respiratory maladies.

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The regulations could affect formulation of lubricants used in heavy-duty internal combustion engines by requiring increased compatibility with NOx control technologies.

The new rule is the U.S.’ first upgrade of heavy-duty truck emissions since 2001 and would lower the cap on NOx by nearly 50%. EPA said manufacturers will achieve this largely through use of technologies developed in the past 20 years, along with others now in the works.

The greater impacts on the auto industry are likely to result from rule changes expanding where those caps apply. Manufacturers will have to prove that their vehicles will remain in compliance with the caps for a much longer period of time. Manufacturers will also have to ensure that emissions control systems are tamper proof.

The new regulation will close loopholes that made the emissions limits non-applicable during certain driving conditions, including some that generate significant amounts of NOx, EPA said. The rule also expands the range of vehicles covered to include virtually all on-highway trucks, buses and vans.

Some environmental groups criticized the administration for not going further – for example for not requiring a quick shift to electric trucks, which would eliminate NOx emissions.

NOx emissions limits on vehicles with internal combustion engines affect engine oil performance demands by requiring oils to accommodate control technologies such as selective catalytic reduction and exhaust gas recirculation. Use of these technologies has previously required lubricants to tolerate higher acid levels and more soot and led to lower caps on levels of chemicals such as phosphorus.