The Environmental Protection Agency has scheduled 2022-24 release of rulemakings to extend the sharp reduction of heavy-duty truck emissions realized from the 2010 measure that standardized diesel particulate filter, selective catalytic reduction, and related exhaust treatment system components in on- and on/off-highway fleets.
Initial “Clean Trucks Plan” action, applicable to 2027 and later model year Class 8 vehicles, will set new nitrogen oxides (NOx) emissions thresholds, which are capped at 0.2-gram brake-horsepower-hour in EPA 2010-compliant exhaust treatment systems. “Although those standards achieved important NOx reductions, new technologies can help achieve the additional reductions,” according to the EPA Office of Transportation and Air Quality. “State and local agencies across the country have asked the EPA to issue regulations that further reduce NOx emissions from heavy-duty trucks in order to protect the health of their communities.”
“One area where technologies can improve emission outcomes relates to trucks operating at what are known as ‘low loads,’” the agency observes. “EPA’s analysis of trucking emissions has shown that current NOx controls are not effective under certain low-load operating conditions, such as when trucks idle, move slowly, or operate in stop-and-go traffic. Technologies that can help reduce NOx emissions under low-load conditions now exist, and they represent one area where EPA intends to focus.”
In addition to NOx reduction measures, the agency will target upgrades to current Phase 2 greenhouse gas (GHG) emission guidelines, which went into effect with 2021 model year trucks, and will continue with more stringent guidelines for 2024 and 2027 deliveries. Action on GHG standards will proceed with an eye to capturing shifts to zero-emission technologies in certain heavy-duty vehicle segments.
“Zero-emission heavy-duty trucks have begun entering the market in volumes that were not foreseen when EPA began the Phase 2 GHG program,” the agency observes, “The number of products available, as well as production volumes, are expected to accelerate in the next few years. EPA will assess the impact these zero-emission technologies will have on the overall effectiveness of the Phase 2 program and whether targeted adjustments to GHG standards in 2027 may be warranted.”
EPA announced the “Clean Trucks Plan” in conjunction with new fuel economy standards and greenhouse gas emissions reduction strategies for light duty trucks and passenger vehicles.