Ozone (2015 8-Hour Standard)

Current Status:

Nonattainment – Marginal Area*

Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Weld and portion of Larimer county

Attainment Deadline

August 3, 2021

*EPA proposed reclassification to Moderate April 13, 2022

Summary

In April 2018, the U.S. Environmental Protection Agency (EPA) finalized designations, with an effective date of August 3, 2018. The Denver Metro/North Front Range Area (DM/NFR) area was designated as a Marginal nonattainment area with an attainment date of August 3, 2021 (based on the three-year average of monitored ozone values from 2018 through 2020). Based on 2018 – 2020 ozone monitoring data the area failed to attain the 2015 Standard by the Marginal area attainment date and, as such, on April 13, 2022 the EPA proposed to reclassify the DM/NFR nonattainment area to Moderate under the 2015 Standard with an attainment date of August 3, 2024.

State Implementation Plan (SIP) Documents

Moderate Area SIP Development (2021-2022)

Draft SIP Chapters Presented to RAQC Board

Federal Rules and Actions

Infrastructure SIP Approval (85 FR 20165, Apr. 10, 2020)

Implementation Rules

Final Rule (81 FR 62998, Dec. 06, 2018)

Proposed Rule (81 FR 81276, Nov. 17, 2016)

RAQC Comments (Feb. 13, 2017)

Colorado Department of Public Health and Environment (CDPHE) Comments (Feb. 13, 2017)

Classification Rule (83 FR 10376, March 1, 2018)