Key facts
- CO cannot be seen, smelled or tasted.
- Fuel-burning appliances, vehicles, generators and fires can produce CO.
- Headache, dizziness, nausea, weakness and confusion can be warning symptoms.
- Suspected CO poisoning is an emergency: move to fresh air and seek medical help.
Common carbon monoxide sources
Any fuel-fired appliance can produce CO, especially when it is incorrectly installed, poorly maintained or inadequately vented. Furnaces, heaters, stoves, fireplaces, generators and vehicles are common examples.
Never operate a vehicle in a garage or a portable fuel-fired generator inside or close to a building. Outdoor AQI readings do not replace a working indoor CO alarm.
Symptoms and immediate action
- Headache, dizziness or nausea
- Weakness, shortness of breath or confusion
- Flu-like symptoms without fever
- Loss of consciousness or death at high exposure
Preventing indoor CO exposure
- Install and maintain CO alarms according to manufacturer instructions and local codes.
- Have fuel-burning appliances, chimneys and vents inspected by qualified professionals.
- Use generators, grills and other fuel-burning equipment only in safe outdoor locations.
- Do not use an outdoor AQI value to judge whether indoor air is safe.
Frequently asked questions
Can I smell carbon monoxide?
No. CO is colorless and odorless, which is why working carbon monoxide alarms are important.
Will an air purifier remove CO?
Typical particle filters do not remove carbon monoxide. Remove the source, ventilate only when safe, and follow emergency guidance.
Does an N95 protect against CO?
No. An N95 filters particles; it does not supply oxygen or remove carbon monoxide gas.
Sources
This reference was prepared from the following primary public-health and regulatory sources:
- Carbon Monoxide's Impact on Indoor Air QualityUnited States Environmental Protection Agency
- WHO Global Air Quality GuidelinesWorld Health Organization