SACRAMENTO — The California Air Resources Board and the state Attorney General’s office have filed comments challenging federal efforts to re-open evaluation of vehicle emissions standards for model years 2021-2025.

The comments state that any weakening of these rules presents a threat to the health of Americans, the environment and the U.S. economy.

The comments make it clear that compliance with the existing standards is critical for California to reach its federal as well as state air quality standards and climate targets. Agreement on the standards was reached in 2012 between CARB, the U.S. Environmental Protection Agency, and the National Highway Transportation Safety Administration.

“We see no value in revisiting standards that were based on extensive research and analysis by California and federal scientists and engineers, and independent analysts,” said CARB Executive Officer Richard Corey. “We do see a great deal of harm from any delay or weakening of the standards. In fact, we believe that any further discussions should look at much stronger rules after these end in 2025, leading to further health protection and saving consumers more at the pump.”

The 2022-2025 model year regulations for greenhouse gas emissions were developed from the most extensive research ever done on vehicle emissions reduction technology, consumer habits and automobile market conditions. (The federal re-assessment includes the NHTSA fuel efficiency standards that commence one year earlier, in 2021.)

The voluminous Technical Assessment Report, developed and released jointly in 2016, fully supports the required mid-term evaluation by both the federal agencies and CARB that the greenhouse gas standards for those model years are reasonable and achievable.

Additional studies since then show the standards are even easier to achieve than previously believed and can be tightened.

The final federal determination on the mid-term evaluation was made in January; CARB affirmed the standards, based on its own analysis, in March.

“It is critical that EPA and NHTSA keep these achievable standards in place,” said Attorney General Xavier Becerra. “These standards will help our children breathe cleaner air and will help us tackle climate change, the most important global environmental issue of our time. California knows there’s no turning back in the fight against pollution.”

California’s comments make clear that weakening the standards presents health and environmental risks to all Americans and put a damper on technological innovation. Weakening the standards will cost consumers money at the pump, and exposes them to more fully to the effects of volatile gas prices.

The standards also provide a foundation for further addressing the threat posed by climate change, illustrated most recently by the increased intensity of the current hurricane season.

More than 10 million Californians live in areas the federal government has found regularly fall far short of achieving healthy air quality, and the state is already seeing the impacts of climate change in the form of more intense wildfires, drought, storms and sea level rise.