Ozone planning information for industry


Colorado’s ozone nonattainment area planning

While air quality has improved greatly over the past several decades and ozone concentrations generally trend downward in the Denver Metro/North Front Range area, the area has failed to comply with increasingly stringent federal standards. In June 2018, EPA classified the Denver Metro/North Front Range (DM/NFR) as a “marginal” nonattainment area for the 2015 8-hour ozone standard, effective August 3, 2018. The attainment deadline for the 2015 standard is August 3, 2021, based on 2018-2020 ozone season data. In January 2020, EPA classified the DM/NFR as a “serious” nonattainment area under the 2008 ozone standard. The attainment deadline for the 2008 standard is July 20, 2021, based on 2018-2020 ozone season data. See history of ozone in Colorado for additional information. 

The Air Pollution Control Division (Division), the Air Quality Control Commission (Commission), and the Regional Air Quality Council, along with other local partners, continue to evaluate and implement control strategies aimed at reducing emissions, particularly precursors to the formation of ozone - nitrogen oxides (NOx) and volatile organic compounds (VOCs). 


Severe Ozone Planning 

Colorado is actively planning next steps in addressing ozone in the North Front Range. APCD will host two listening sessions that will share basic ozone information, identify planning processes and potential reduction strategies, and provide opportunities to share concerns and suggestions.


Past planning efforts include:

  • In 2017 the Division launched a voluntary emission reduction program with industry in the DM/NFR area. Program participants receive emails two to three days before a forecasted high ozone day. Participants are encouraged to implement voluntary emissions reduction actions on the forecasted high ozone days.

  • In July 2018, the Commission adopted Reasonably Available Control Technology (RACT) requirements for major sources of NOx in the DM/NFR

  • In November 2018, the Commission adopted categorical RACT requirements for breweries and wood furniture coating operations that are a major source of VOCs in the DM/NFR.

  • In July 2019, the Commission adopted VOC content limits to reduce emissions from consumer products and architectural, industrial and maintenance coatings.

  • At the Commission's directive, the Division initiated and led the Statewide Hydrocarbon Emissions Reduction (SHER) stakeholder process and the Pneumatic Controller Task Force (PCTF) over the 2018-2019 timeframe. The SHER Team evaluated topics including the frequency of leak detection and repair inspections, transmission segment compressor emissions, and natural gas-driven and zero emission pneumatic controllers state-wide. The SHER Team’s efforts informed a 2019 rulemaking proposal. The PCTF completed a study of rates of improper operation for pneumatic controllers in the DM/NFR nonattainment area in June 2020. The PCTF used the results of this study to understand the costs and effectiveness of the current pneumatic controller inspection program. PCTF findings and recommendations were presented to the Commission in August 2020.

  • In September 2020, the Commission approved new rules that require emissions monitoring at oil and gas sites during the early stages of operations at new oil and gas wells. The rules require operators to report carbon dioxide and N2O emissions. The rules also set emission standards for natural gas-fired reciprocating internal combustion engines equal or greater to 1,000 horsepower.

For additional information, see the Division’s ongoing stakeholder processes and the Regional Air Quality Council air quality planning


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