California regulators have issued a proposal focused at lowering particulate matter emissions for new trucks built beginning in 2024, but federal regulators are still working to craft a separate nationwide low-NOx and PM proposal scheduled to take effect in 2027. Additionally, California Air Resources Board (CARB) and the U.S. Environmental Protection Agency staff hope to synchronize their regulations.
What are the consequences if the two rules are different? This is a question that Glen Kedzie, environmental affairs counsel for American Trucking Associations, has been posed.
“As CARB and EPA both race to the finish line in finalizing their separate regulatory approaches to address NOx emission reductions from new trucks, it remains unsettling that at this late stage in the game there still remains a lack of clarity in California’s overall approach and how it may impact national sales of low-NOx equipment in advance of a federal standard,” Kedzie said.
In May of 2020, CARB released a number of proposed emissions-reduction amendments designed to keep the state’s air clean while it transitions to an all-electric truck future by 2045.
“CARB staff has been encouraging EPA to align as much as possible with our proposal, in terms of both stringency and timing,” said a CARB spokeswoman. “However, we recognize that due to federal lead time constraints, the [federal] Clean Trucks Initiative is likely to take effect approximately three years after CARB’s omnibus proposal.”
Federal documents indicate that the EPA is also aiming to issue their federal proposal as early as September of this year, with a final rule issued in July 2021. This schedule takes into account the time needed to publish in the Federal Register, for the agency to propose, conduct public hearings, receive and review public comments, perform data analysis and research that are pertinent to issuing sound final actions.
Meanwhile, CARB plans to begin discussions on its proposed rules at its next board meeting on Aug. 27, 2020.
The amendments include:
- Proposal to reduce the current heavy-truck NOx standard from 0.20 grams per brake horsepower hour to 0.050 g/bhp-hr from 2024 to 2026, and even lower to 0.020 g/bhp-hr in 2027.
- Proposal to reduce heavy-truck particulate matter emissions from its current emission standard of 0.01 g/bhp-hr to a standard of 0.005 for 2024 and subsequent model-year engines.
- Proposal to require truck manufacturers to extend the criteria pollutant emission warranty and useful life period requirements for heavy-duty vehicles and engines.
- Proposal to include requirements beginning in 2024 for heavy-duty on-board diagnostic systems to represent vehicle operations in real-world conditions, establishing clear criteria for engine family pass/fail determination and on-board diagnostic data during testing to verify the condition of the test vehicle and sensors.
According to California’s emission inventory model, almost a million heavy-duty vehicles operate on its roads each year.
“These vehicles are significant sources of oxides of nitrogen, particulate matter and greenhouse gas emissions,” CARB said in a summary of the amendments. “In fact, heavy-duty vehicles comprise the largest NOx emission source category in the state, contributing to 31% of all statewide NOx emissions as well as 26% of total statewide diesel particulate matter emissions.”