2025 State Area Designations Regulation

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This page last reviewed December 17, 2025

Proposed 2025 Amendments to Area Designations for State Ambient Air Quality Standards

Public Comments Received Second Batch of Public Comments Received
Final Approval / OAL Action

OAL has approved this rulemaking and filed it with the Secretary of State on August 12, 2026.  The effective date of the regulation is October 1, 2026.

Final Statement of Reasons
Final Regulation Order
Final Regulation Order - Alternative Format
Adopted Regulations and Materials Submitted to OAL

The Final Package was submitted to OAL on July 3, 2026.  OAL has until August 14, 2026, to make a decision.

Final Statement of Reasons  (See Revised Above)
Updated Informative Digest
Executive Order
Final Regulation Order  (See Revised Above)
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Public Hearing Notice and Related Material
Posted
Notice of Comment Period (Deadline to Request a Public Hearing, December 29, 2025)
Staff Report: Initial Statement of Reasons
Appendix A-1: Proposed Regulation Order
Appendix A-2: Alternative Regulation Order
Appendix B: Area Designations Criteria
Appendix C: Maps and Tables of Area Designations for State and National Ambient Air Quality Standards
Appendix D: Convention for Rounding Ambient Air Quality Data
Appendix E: Designation Values and Expected Peak Day Concentrations
Appendix F: Designation Value Tables