Ozone NAAQS Timelines
| Key Dates for Ozone NAAQS Nonattainment Areas | 1997 NAAQS | 2008 NAAQS | 2015 NAAQS |
|---|---|---|---|
| Emission statement rule, emission inventory, and Moderate area/OTR RACT SIPs | June 2006 | July 2014 | August 2020* |
| Marginal area attainment date | June 2007 | July 2015 | August 2021* |
| Attainment plans and demonstrations for initial Moderate areas | June 2007 | July 2015 | August 2021 |
| Attainment plans and demonstrations for initial Serious and above areas | June 2007 | July 2016 | August 2022 |
| Moderate area SIPs for 11 reclassified Marginal areas | -- | January 2017 | -- |
| Moderate area attainment date | June 2010 | July 2018 | August 2024 |
| Serious area SIPs for reclassified 2008 Moderate areas | -- | August 2020 | -- |
| Serious area attainment date | June 2013 | July 2021 | August 2027 |
| 1997 NAAQS revoked | April 2015 | -- | -- |
| Severe area attainment date | June 2019 | July 2027 | August 2033 |
| Extreme area attainment date | June 2024 | July 2032 | August 2038 |
* For the San Antonio Marginal nonattainment area for the 2015 ozone NAAQS, the month is September instead of August.
| Action | Planned Dates: After NAAQS Promulgation | Issue Date |
|---|---|---|
| Final 2015 Ozone NAAQS revision, monitoring rules, exceptional event demonstration schedule, and PSD permit grandfathering provision | Upon promulgation | October 1, 2015 |
| Propose Exceptional Events Rule revision and guidance on wildfire-related ozone demonstrations | 1 month | November 10, 2015 |
| Area designations guidance (including Rural Transport Areas) | 4 months | February 25, 2016 |
| Final update to PSD permit modeling guideline (Appendix W; proposed July 2015) | 8 months | December 20, 2016 |
| Draft PSD MERPs guidance | 8 months | December 2, 2016 |
| Final PSD SILs guidance | 8 months | April 17, 2018 |
| Final Exceptional Events Rule revision and guidance on wildfire-related ozone demonstrations | 10 months | September 16, 2016 |
| Propose nonattainment area rules/guidance (including area classifications, SIP due dates, nonattainment NSR provisions) | 12 months | November 2, 2016 |
| Interstate ozone transport contribution assessment provided to States | 12 months | January 6, 2017 |
| Final area designations (attainment/unclassifiable) | 24 months | November 6, 2017 |
| Final classifications rule | 24 months | March 1, 2018 |
| Final area designations (nonattainment) | 24 months | April 30, 2018 (most of U.S.) July 17, 2018 (San Antonio) |
| Final SIP requirements rule | 24 months | November 7, 2018 |
| Update to transportation conformity guidance | 25 months | June 14, 2018 |