The northern Front Range had only 23 days violating EPA caps for toxic ground-level ozone in the 2025 summer season, a steep fall from the record 67 days in 2021, according to a preliminary review in conversations with the Regional Air Quality Council. Only seven of those 2025 high-ozone days were in the worst category above 75 parts per billion.

Though the season isn’t technically over yet, RAQC officials don’t expect late-September weather to result in more violations in 2025, and are pleased with a 120-day ozone season that saw far fewer exceedances than the 41 violation days in 2024.

With Colorado air pollution control officials under strict EPA orders to reduce violations and bring Front Range emissions consistently below 70 parts per billion through new policy controls on driving,

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