https://www.boulderweather.com/tags/cdphe/Recent content in Cdphe on BoulderWeather.comHugo -- gohugo.ioenBoulderweather.comMon, 07 Sep 2026 00:00:00 +0000https://www.boulderweather.com/post/front-range-ozone-action-days-boulder/Mon, 07 Sep 2026 00:00:00 +0000https://www.boulderweather.com/post/front-range-ozone-action-days-boulder/ <h2 id="ground-level-ozone-a-different-kind-of-front-range-air-alert">Ground-Level Ozone: A Different Kind of Front Range Air Alert</h2> <p>Why does Boulder's air quality sometimes worsen on a clear, smoke-free summer afternoon with no fire in sight? The answer is a pollutant that behaves nothing like wildfire smoke: ground-level ozone. The alert built around it is called an Ozone Action Day, issued jointly by the <strong><a href="https://cdphe.colorado.gov/ozone-pollution-and-your-health">Colorado Department of Public Health and Environment</a></strong> and the Regional Air Quality Council for the Front Range Urban Corridor -- the stretch running from Douglas County north through the Denver-Boulder area, Fort Collins, and Greeley into Larimer and Weld counties.</p>