Indoor Air Quality

The Larimer County Department of Health and Environment does not inspect, test, or enforce indoor air quality (including mold) or living condition issues for rental or privately owned properties. If you are renting within the city of Fort Collins and have concerns regarding your indoor environment or living conditions, visit this City of Fort Collins website to learn more. 



Ozone Action Alerts

The Larimer County Department of Health & Environment focuses on improving outdoor air quality in Larimer County by: 

  • Performing ambient air monitoring for carbon monoxide, ozone, particulates-PM10 and PM 2.5
  • Inspecting minor stationary sources permitted through the Colorado Department of Public Health and Environment, Air Pollution Control Division
  • Performing CFC compliance inspections
  • Issuing open burn permits
  • Investigating air quality complaints

We are not directly involved with the Mobile Emissions Program which regulates automobile emissions and other transportation issues. Indoor Air Quality is not regulated in private residences.

For businesses that might need air quality permits for their businesses, visit the State Department of Public Health Small Business Assistance Program.

    On June 9, 2022, the Larimer County Department of Health & Environment provided an overview of air quality in Larimer County, including the sources and contributors to ground-level ozone, potential health impacts of poor outdoor air quality, public health’s role in addressing air quality issues, and information about how residents can help improve air quality in Larimer County. View the recording here.

    A EPA downgrade from serious to severe violator will require implementation of several new measures aimed at reducing air pollution;

    1. Gas stations in the Northern Front Range will be required to sell cleaner-burning gasoline. Many expect this change to be enacted in summer 2024.
    2. The threshold for when a business must obtain a permit and control their emissions will be lowered, resulting in just under 500 new sources that will face stricter controls.
    3. Requirements for those with existing permits become more stringent. 
    4. Additional resources for staff, monitoring equipment, and pollution reduction programs will become available as a result of the downgrade. 


    Ground level ozone or "bad" ozone is not emitted directly into the air but is created by chemical reactions between NOx and VOCs in the presence of health and sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of oxides of nitrogen (NOx) and volatile organic compounds (VOCs). 


    ground level ozone

    Gas powered lawn equipment contributes roughly half of the ozone producing pollutants as all of the light duty vehicles, and newer electric versions are convenient and quiet.

    The Sources of Air Pollution

    A number of sources – activities that cause pollution to be emitted into the air – contribute to poor air quality and ground-level ozone formation. 

    • Mobile sources – such as cars, buses, planes, trucks, and trains
    • Stationary sources – such as power plants, oil refineries, industrial facilities, and factories
    • Area sources – such as agricultural areas, cities, and wood burning fireplaces
    • Natural sources – such as wind-blown dust, wildfires

    Regionally, transportation-related emissions make up a little more than half of our regions NOx, and around 30% of the VOC contributions. Regionally, 28% of NOx and 44% of VOC contributions are from oil and gas production. 



    The largest contributor of NOx and VOCs in Larimer County is transportation, at 70% and 55%. 





    In areas of poor air quality, children and the elderly are most vulnerable to health effects.

    • Eyes, nose, and throat irritation
    • Shortness of breath, decrease in lung function
    • Can make asthma and other respiratory symptoms worse
    • Increase in ER and Urgent Care visits with increase in ozone
    • Avoid exercise during the hottest part of the day
    • Some people should limit or avoid prolonged exertion outdoors on high ozone days:
      • Children and older adults
      • Those with lung disease
      • People who are active outdoors

    In partnership with the State’s Air Pollution Control Division, we have six additional sites monitoring for ozone this summer in Bellvue, Fort Collins, Livermore, and Loveland. The data from these temporary sites will be evaluated to determine if more permanent regulatory monitoring sites would be beneficial to the modeling of air pollution in our area.

    A major contributor to air pollution that can easily be overlooked are our gas powered small engines. Lawn mowers, trimmers, leaf blowers, chainsaws. This equipment typically is not equipped with emission controls like most vehicles do and we are working on expanding the regional program for replacement of this equipment to more Larimer County residents. 

    Finally, our staff are trained to identify violations at these facilities, respond quickly to reports of odors, and work closely with the state on enforcement. In several cases we have worked with the state to add additional monitoring equipment in the area where a complaint has been received to help investigate the issue.


    • Carpool or use public transportation, bike, or walk whenever possible
    • Avoid idling in your car
    • Maintain proper air pressure in tires
    • Refuel your car in the evening when it's cooler
    • Follow gasoline refueling instructions for efficient vapor recovery, being careful not to spill fuel and always tightening your gas cap securely
    • Delay lawn and gardening work that uses gasoline-powered equipment until after 7pm
    • Use paint and cleaning products with fewer or no volatile organic compounds

    1. Allocate funding to Regional Air Quality Council (RAQC) for Larimer County residents to participate in the Mow Down initiative.

    Decrease emissions from nonpoint sources that are known to contribute to ground-level ozone.   The pilot in the fall of 2022 was successful and LCDHE is planning with the RAQC for 2023. Additional outreach and grants for commercial landscapers are planned for this summer.

    2. Ensure oil and gas operators submit Financial Assurance Plans and engage operators on plugging and abandoning low-producing wells. 

    Reduction in hydrocarbon emissions including VOCs and methane from low producing wells. Being led by Larimer County Planning through their consultant. These meetings are occurring and the county has identified ~100 low producing wells that are subject to these rules.

    3. Locate a new regulatory monitoring site, based on results of temporary ozone monitors placed in west Loveland, Livermore, and Bellvue.

    Additional data that contributes to air quality planning and regulatory activities in our region. Two sites have been identified and LCDHE is in the process of getting approvals from the City of Loveland and Poudre School District to locate the monitors.

    4. Purchase and use of an infrared optical gas imaging (IR) camera to Air Quality inspection program. 

    Reduction in hydrocarbon emissions including VOCs and methane from stationary sources of pollution. The camera has been purchased and LCDHE is awaiting delivery, expected from the manufacturer 5/15.

    Other Air Quality Resources

    Air Quality

    Department of Health and Environment - Environmental Health