Last week, the U.S. Environmental Protection Agency (EPA) took two actions related to mobile source emissions under the Clean Air Act that represent the agency’s continued focus on transportation, climate change, and environmental justice.
On March 7, 2022, EPA announced newly proposed emission standards for heavy-duty vehicles and engines, which would apply starting in model year 2027. The proposed standards would reduce allowed emissions of nitrogen oxides from heavy-duty gasoline and diesel engines and set more stringent greenhouse gas standards for certain commercial vehicle categories. Beyond numerical reductions in emissions, the rule also indicates EPA’s broader shift in focus to environmental justice. The proposed rule’s supporting materials outline EPA’s position that emissions from heavy-duty engines have disproportionately affected communities of color and low-income families, noting that “The largest air quality improvements are predicted to occur in areas with the worst baseline air quality, where larger numbers of people of color are projected to reside.”
On March 8, 2022, EPA restored the waiver previously provided to California under the Clean Air Act to implement emissions standards for cars and light trucks more stringent than federal standards. These standards were issued under California’s Advanced Clean Car Program starting in 2013 and include greenhouse gas emission standards and a zero-emission vehicle sales mandate. EPA rescinded the waiver in 2019 based on an interpretation by the National Highway Traffic Safety Administration that California standards effectively regulated fuel economy and were therefore preempted by the Energy Policy and Conservation Act. Based on the new reconsideration, California’s waiver has been reinstated. Prior to the recission in 2019, various other states adopted California’s standard to follow the same requirements. In 2019, by revoking California’s waiver, EPA essentially cancelled the adoption of those standards by other states. With its action last week, EPA restored the ability of other states to adopt and enforce the California standards in lieu of the federal standards.
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