On this page:

• Rule Summary
• Additional Resources

Rule Summary

Clean Air Act Section 211(v) requires EPA to complete an “anti-backsliding study” to determine whether the renewable fuel volumes required in the Act adversely impact air quality as a result of changes in vehicle and engine emissions. After considering the results of the study, EPA is required to either (1) promulgate fuel regulations to implement appropriate measures to mitigate, to the greatest extent achievable, any adverse impacts on air quality; or (2) determine that no such measures are necessary.

On January 6, 2021, EPA determined that no additional measures are necessary pursuant to Clean Air Act (CAA) section 211(v) to mitigate the adverse air quality impacts of the renewable fuel volumes required under CAA section 211(o). Since 2017, EPA has been implementing the Tier 3 Motor Vehicle Emissions and Fuel Standards which are more stringent and reduce concentrations of ozone, PM2.5, NO2, and air toxics now and in the future.  In making this determination, EPA considered the analyses performed for the Tier 3 rulemaking, as well as the anti-backsliding study.

EPA provided a 30-day comment period for the public to comment on the proposed determination. The comment period closed on July 8, 2020.

Additional Resources

• Final Determination for Renewable Fuels and Air Quality Pursuant to Clean Air Act Section 211(v) (PDF) (21 pp, 1 MB, January 2021, EPA-420-R-21-002, About PDF)
• Federal Register Notice of Final Determination (PDF) (1 pp, 221 K, published January 15, 2021, About PDF)
• Clean Air Act Section 211(v)(1) Anti-backsliding Study (PDF) (92 pp, 4.5 MB, May 2020, EPA-420-R-20-008, About PDF)
• Anti-backsliding Study (ABS) Supplemental MaterialsFree Viewers
  • ABS AQ Modeling Outputs (ZIP) (164 K, May 2020)
  • ABS Inventory Summaries (ZIP) (18 K, May 2020)
  • ABS MOVES Fuel Formulation Tables (ZIP) (6 K, May 2020)
  • ABS MOVES Inventory Development (ZIP) (2.3 GB, May 2020)
• Federal Register notice of availability and request for public comment (PDF) (2 pp, 272 K, published June 8, 2020, About PDF)
• Proposed Determination for Renewable Fuels and Air Quality (PDF) (14 pp, 892 K, May 2020, EPA-420-D-20-003, About PDF)