Document Archives Reports

4th Maximum Ozone Values Table (ppb) through September 10, 2017

Posted Under: News Room - News, Ozone (8-Hour Standard)

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The Denver Metro/North Front Range area is designated as nonattainment by the U.S. Environmental Protection Agency (EPA) for the pollutant ozone. The 2008 8-Hour Ozone Standard is 75 parts per billion (ppb) and is calculated using a rolling three-year average of the fourth (4th) highest daily 8-hour ozone concentration.

The table linked above shows current monitoring data for the nonattainment area, including the top four (4) values for each monitoring site for the current ozone season as well as the 4th highest values for the previous two years. The 4th highest values over a three-year period are averaged to determine the Design Value (DV) at each monitor. The highest DV is the test of attainment, with all monitors having to be at or below the standard.

The RAQC’s ozone education campaign, Simple Steps. Better Air., issues Ozone Action Alerts as well as notices about upcoming community events. The public is encouraged to participate in efforts to reduce air pollution by joining the Clean Air Community and using the OzoMeter to track air quality impacts.

For additional information on ground-level ozone, please visit or call (303) 629-5450, ext. 220.

Click here to view previous tables

Attainment Demonstration Modeling for the Denver Metro/North Front Range 2017 8-Hour Ozone State Implementation Plan (SIP) – Draft Modeling Protocol

Posted Under: Modeling, News Room - News


The RAQC is in the process of conducting modeling needed to demonstrate attainment of the current March 2008 ozone National Ambient Air Quality Standard (NAAQS) in Denver Metro/North Front Range region by 2017.  This Modeling Protocol guides the technical details of a modeling study and provides a formal framework within which the scientific assumptions, operational details, commitments and expectations of the various participants can be set forth explicitly and means for resolution of potential differences of technical and policy opinion can be worked out openly and within prescribed time and budget constraints.  Current modeling is being carried out by a contracting team consisting of Ramboll Environ US Corporation and Alpine Geophysics, LLC under contract to the Regional Air Quality Council (RAQC).

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