Wood smoke and your health

Log fire burning in dark fireplace

This page has information about health concerns related to indoor burning, prescribed fires, and open burns.

For wildfire information, visit Wildfire Smoke and Health.

Whether you will experience health impacts from wood smoke depends on many factors, including what’s in the smoke, how long you’re exposed, how much you’re exposed to, and your health history and lifestyle factors. Breathing in wood smoke can:

  • Irritate the eyes, nose, and throat.
  • Cause wheezing, coughing, and difficulty breathing.
  • Worsen asthma, other lung diseases, and heart diseases.

Wood smoke can affect anyone, populations at greater risk include children, older adults, pregnant people, people with lung disease or heart disease, outdoor workers, and people with limited access to medical care.

For medical emergencies, call 911. See a health care provider if your symptoms get worse, don’t go away, or disrupt your daily activities.  


Stay informed


Reduce your exposure

Coloradans need to have information to make decisions for themselves and their families. Some of these recommendations may not always be practical or affordable.


Tips to take if you're near a prescribed burn.

  • Check the air quality before going outdoors.
  • Stay indoors if the air quality is bad. Close windows and doors. This is especially important for children and other higher risk groups.
  • Limit activity outdoors in heavy smoke.
  • During periods of heavy smoke, use an N95 respirator outdoors.
    • Other kinds of masks, such as cloth, surgical, or paint masks, do not prevent breathing in smoke.
    • People with heart or lung conditions should check with a doctor before wearing a respirator. 
  • Reduce smoke in your vehicle. Close the windows and vents. Run your car’s air conditioner in recirculate mode to reduce air intake from outside.
  • Smoke can be worse at night. Take extra precautions if you need to go out, and close the windows when you are indoors. 
  • Monitor prescribed burns in Colorado.  
  • Consider temporarily locating to another area if it is safe to do so. Seek out locations where air is filtered such as malls, movie theaters or recreation centers.

Protect indoor air quality when burning wood indoors.

  • Air out your home when outdoor air quality is good. 
  • Reduce fine particle levels using the heating, ventilation and air conditioning (HVAC) system in your home.
    • Run the fan continuously. 
    • Use the highest Minimum Efficiency Reporting Value (MERV) for your system. A filter rated MERV 13 or higher is best to effectively reduce fine particle pollution in indoor air.
  • Consider using a portable air cleaner with a High Efficiency Particulate Air (HEPA) filter or make a filter fan.
  • Limit other activities that increase indoor air pollution. These include:
    • Burning candles.
    • Using gas, propane, and wood stoves.
    • Using aerosol sprays.
    • Frying and broiling food.
    • Smoking and vaping.
    • Vacuuming and sweeping.
  • Keep surfaces clean to reduce particles in the air. Use soap and water to clean ash from hard surfaces. Harsh chemicals can have unexpected chemical reactions with ash.

What is the air quality like where I am?

You can refer to the chart below and estimate the visibility in smoky air to come up with a corresponding air quality category based on the federal Air Quality Index.


Air quality index (AQI) Visibility
Good 10 or more miles
Moderate 5 - 10 miles
Unhealthy for sensitive groups 3 - 5 miles
Unhealthy 1.5 - 3 miles
Very unhealthy 1 - 1.5 miles
Hazardous Less than 1 mile