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Understanding Carbon Monoxide Levels: Essential Information for Homeowners

June 17, 2026 · The Clime Team
Understanding Carbon Monoxide Levels: Essential Information for Homeowners

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas produced by the incomplete combustion of carbon-containing fuels. Common sources include unvented kerosene and gas space heaters, leaking chimneys and furnaces, gas stoves, generators, and automobile exhaust from attached garages. (epa.gov)

Health Impacts of Carbon Monoxide Exposure

Exposure to elevated CO levels can lead to a range of health issues:

  • Low Concentrations: Fatigue in healthy individuals and chest pain in those with heart disease.

  • Higher Concentrations: Impaired vision and coordination, headaches, dizziness, confusion, and nausea.

  • Very High Concentrations: Can be fatal. (epa.gov)

Average CO Levels in Homes

In homes without gas stoves, average CO levels range from 0.5 to 5 parts per million (ppm). Near properly adjusted gas stoves, levels are often between 5 to 15 ppm, while those near poorly adjusted stoves may reach 30 ppm or higher. (epa.gov)

Protecting Your Home from Carbon Monoxide

To minimize the risk of CO exposure:

  • Maintain Appliances: Ensure all fuel-burning appliances are properly installed, maintained, and used according to the manufacturer's instructions.

  • Install CO Detectors: Place CO detectors near sleeping areas and on every level of your home. While these devices can alert you to dangerous CO levels, they should not replace proper appliance maintenance. (epa.gov)

  • Ventilate Properly: Use exhaust fans vented to the outdoors over gas stoves and open flues when fireplaces are in use. Avoid idling cars in attached garages, even with the door open. (epa.gov)

Understanding CO Air Quality Standards

The U.S. Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards (NAAQS) for CO to protect public health and the environment. The current standards are:

  • 1-Hour Average: 35 ppm

  • 8-Hour Average: 9 ppm (epa.gov)

These standards are periodically reviewed to ensure they provide adequate protection.

Conclusion

Carbon monoxide is a serious health hazard that can be mitigated through proper maintenance of fuel-burning appliances, installation of CO detectors, and adherence to safety practices. By staying informed and proactive, you can protect your home and loved ones from the dangers of CO exposure.

Highlights:

  • Carbon Monoxide Trends | US EPA, Published on Wednesday, February 18
  • Setting and Reviewing Standards to Control Carbon Monoxide (CO) Pollution in Outdoor Air | US EPA, Published on Thursday, December 18
  • Integrated Science Assessment (ISA) for Carbon Monoxide | US EPA, Published on Wednesday, October 01

Frequently Asked Questions