The U.S. Environmental Protection Agency (EPA) issued a response to petitions seeking additional regulations relating to the emissions of oxides of nitrogen (NOx), a component of ozone, from heavy-duty on-highway (HDOH) engines and vehicles. The petitioners, with support from the California Air Resources Board (CARB), had asked EPA to adopt a 0.02 g/bhp-hr NOx emission standard based on existing engine-emission certification test procedures.


In its response, EPA does not agree with the petitioners’ specific regulatory request, stating, “[I]n order to achieve cost-effective real-world reductions, [EPA] must look beyond simply reducing the NOx standard over the test procedures and test cycles we currently require. Therefore, it should not be presumed that EPA would eventually propose a NOx standard of 0.02 g/bhp-hr.”


“The assessment of whether, to what extent and how to implement additional HDOH NOx controls must be data-driven, and must take all current regulations into account,” said Jed Mandel, EMA’s President. “It is especially important to ensure that any potential future low-NOx requirements do not compromise compliance with the just-finalized Phase 2 greenhouse gas (GHG) standards, which will improve HDOH fuel economy by more than 25% over the next 10 years.” Mr. Mandel added.


“Even though the HDOH industry already is in the midst of complying with very stringent emission regulations, we are prepared to collaborate on EPA’s envisioned data-driven assessment of potential additional NOx-control strategies.” Mr. Mandel further noted that EPA explicitly stated that, “It is premature to commit to a particular level or form of a future low-NOx standard for heavy-duty vehicles, especially in advance of developing the robust technical record necessary to propose and promulgate such standards.”


EMA already has initiated efforts to collaborate with EPA and CARB on developing the robust technical data that will inform the assessment of a potential lower-NOx program. As EPA acknowledges, it will take significant time to complete the necessary technical work and collaborative research.


EMA looks forward to its engagement and collaboration with all stakeholders on the assessment of a new, harmonized and comprehensive national NOx-reduction strategy for HDOH engines and vehicles. EPA’s response to the previously-filed rulemaking petitions is an important first step in the development of such a harmonized and data-driven approach.


The Truck and Engine Manufacturers Association (EMA) is the trade association representing worldwide manufacturers of internal combustion engines used in applications such as trucks and buses, farm and construction equipment, locomotives, marine vessels, and lawn, garden, and utility equipment as well as the manufacturers of medium and heavy-duty trucks greater than 10,000 pounds gross vehicle weight. EMA works with government and other stakeholders to help the nation achieve its goals of cleaner fuels, more efficient engines, cleaner air and safer trucks and roadways.