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Statewide Advisories

Current Air Quality Conditions
Front Range Current Air Quality Advisories

Air Quality Health Advisories

Ozone Action Day Alert
Issued at: 6/18/2025 2:50:00 PM
Effective: 6/18/2025 4:00:00 PM - 6/19/2025 4:00:00 PM
Issued for: Front Range Urban Corridor from Douglas County north to Larimer and Weld counties, including the Denver-Boulder area, Fort Collins and Greeley

Affected Area: Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer, and Weld Counties

Public Health Recommendations: Increasing likelihood of respiratory symptoms and breathing discomfort in active children and adults and people with lung disease, such as asthma. Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy outdoor exertion.

Outlook: Ozone Action Day Alert is now in effect for the Front Range Urban Corridor. Ozone is expected to be in the Good to Moderate range on Wednesday. However, hot, sunny, and stagnant weather will allow ozone to reach the Unhealthy for Sensitive Groups category on Thursday. The highest ozone concentrations are expected in southern and western portions of the Denver Metro area, along the I-25 corridor towards Fort Collins, and Greeley. For Colorado air quality conditions, forecasts, and advisories, visit: https://www.colorado.gov/airquality/colorado_summary.aspx If possible, please help us reduce ozone pollution by limiting driving gas and diesel-powered vehicles until at least 4 p.m. Thursday, June 19, 2025. Colorado is also addressing ozone pollution through state policies. For more information about health impacts and how ozone pollution forms in Colorado, visit: https://cdphe.colorado.gov/ozone-pollution-and-your-health


Colorado Smoke Outlook
COLORADO SMOKE OUTLOOK:
Thursday, July 11, 2024, 8:40 AM MDT

Smoke from out-of-state fires will begin affect northern Colorado by late Thursday morning, and is expected to continue spreading eastward as the day goes on. The majority of smoke will remain in the upper atmosphere, although some will mix down to the surface. Hazy skies are likely across much of northern and western Colorado. Light to moderate smoke is possible Thursday in northwest Colorado, especially Steamboat Springs, Craig, and Meeker.
No major public health impacts are expected due to smoke (fine particulates), however unusually sensitive people, should consider reducing prolonged or heavy exertion on Thursday.

Light to moderate concentrations of smoke are also possible near small wildfires and prescribed burns around the state.

What if there is a wildfire or smoke in your area?
The focus of the Colorado Smoke Outlook is on large fires (e.g., greater than 100 acres in size). Nevertheless, smoke from smaller fires, prescribed fires, and/or smoke from new fires not yet known to CDPHE air quality meteorologists may cause locally heavy smoke. If there is smoke in your neighborhood, see the public health recommendations below.

Public health recommendations for areas affected by smoke:
If smoke is thick or becomes thick in your neighborhood you may want to remain indoors. This is especially true for those with heart disease, respiratory illnesses, the very young, and the elderly. Consider limiting outdoor activity when moderate to heavy smoke is present. Consider relocating temporarily if smoke is present indoors and is making you ill. To temporarily relocate to an area with better air quality, consider using this map (https://fire.airnow.gov/) to identify the best area closest to you. IF VISIBILITY IS LESS THAN 5 MILES IN SMOKE IN YOUR NEIGHBORHOOD, SMOKE HAS REACHED LEVELS THAT ARE UNHEALTHY.
Additional Information

ACTION DAYS: An Action Day for fine particulate matter (particulates), carbon monoxide, ozone or other pollutants indicates that either current air quality is unhealthy or conditions are expected to worsen later in the day or on the next day. Action Days for air pollutants generally indicate that air quality will be in either the Unhealthy or Unhealthy-for-Sensitive-Groups categories according to the Air Quality Index. Action Days trigger voluntary pollution prevention measures, which may vary by season, and public health recommendations.

The AIR QUALITY INDEX reports the daily level of air pollution on an hourly basis. The index reports the highest level of either carbon monoxide, fine particulates or ozone depending on which pollutant has the greatest hourly concentration. Values greater than 100 for carbon monoxide, fine particulates and ozone indicate exceedances of the pollutant's state and federal standards. Air Quality Index values between 0-50 are good, 51-100 moderate, 101-150 unhealthy for sensitive groups, 151-200 unhealthy, 201-300 very unhealthy, and over 300 hazardous.

COLORADO OPEN BURN FORECAST: For those with permits for Open Burning, that is burning of waste materials or vegetation outside, check the following webpage to find out if open burning is allowed today:
http://www.colorado.gov/airquality/burn_forecast.aspx

FOR CURRENT AIR QUALITY INFORMATION AND UPDATES:
http://www.colorado.gov/airquality/advisory.aspx
http://www.colorado.gov/airquality/air_quality.aspx

ABOUT THE AIR QUALITY INDEX:
http://www.epa.gov/airnow/aqi_brochure_08-09.pdf

SOCIAL MEDIA AND AIR QUALITY NOTIFICATIONS:
http://www.facebook.com/cdphe.apcd
http://twitter.com/#!/cdpheapcd
http://www.enviroflash.info/signup.cfm