EPA Announces Cleaner Trucks Initiative

EPA recently announced it will promulgate regulations to further reduce nitrogen oxide (NOx) emissions from highway heavy-duty trucks and engines.  The announcement of EPA’s Cleaner Trucks Initiative comes on the heels of petitions for rulemaking from several state and local air agencies.  Petitioners requested that EPA take the following actions:

1. Begin rulemaking to develop an “ultra-low” NOx emissions standard for on-road heavy-duty engines;
2. Propose on-road heavy-duty diesel engines meet new standard by model year 2022 (i.e., by January 1, 2022);
3. Develop phase-in requirements to fully implement the new standard by January 1, 2024; and
4. Develop guidelines to allow owners of existing heavy-duty vehicles meeting the current standard to qualify for incentive funding to purchase ultra-low NOx engines.

Although no specific action was taken to begin the rulemaking process, EPA pledged to begin studying, meeting with stakeholders, and gathering data to develop a new and revised standard as requested.

The most recent NOx standards for highway heavy-duty trucks and engines were promulgated in 2001.  Since that time, NOx emission standards for these types of engines have contributed significantly to an overall reduction of the national NOx emissions inventory. According to EPA, current regulations have resulted in the reduction of more than 40% of NOx emissions in the U.S. over the last decade.

However, the Clean Air Act requires EPA “from time to time” to revise emission standards for motor vehicles to “reflect the greatest degree of emission reduction achievable” given available technology.  The recent announcement indicates EPA agreed with petitioners and believes more reductions are achievable and necessary.

NOx is a major precursor of ozone and PM_2.5.  In some areas of the U.S., particularly in high population density regions like California and the Northeast, heavy-duty trucks comprise the largest category of NOx emissions sources.  Petitioners and EPA agreed further reductions in NOx emissions will be integral to these regions achieving or maintaining attainment of National Ambient Air Quality Standards for ozone and PM_2.5.

As part of the Cleaner Trucks Initiative, EPA stated it will work with truck and engine manufacturers, suppliers, and state and local air agencies throughout the process to gather data and input, prior to preparing a notice of proposed rulemaking.  The stakeholder process will likely take approximately 24 months, giving EPA time to develop a data-driven proposal for rulemaking.  As updates become available, we will share them with you.