About Carbon Monoxide

Carbon monoxide is a gas that is present in the air, but it’s the presence of high levels—such as those emitted by burning fuel—that can make this gas deadly. Carbon monoxide is a pollutant formed by the combustion of hydrocarbon fuels, including natural gas, propane, wood, coal, and gasoline, among others. All combustion appliances and equipment around the home produce CO gas, no matter how energy-efficient they are.

This poisonous gas is odorless, colorless, and tasteless, which is what makes it so dangerous. The health concerns occur because when CO enters your lungs, it binds to the hemoglobin of red blood cells, taking the place of oxygen. This leads to oxygen starvation (hypoxia) of the blood cells.

CO is measured in parts per million, or ppm. Symptoms of CO exposure worsen with longer and higher exposure:

0.5–5 ppm: Normal level of CO for homes with combustion appliances.

• Below 70 ppm: Exposure for 6 to 8 hours can lead to symptoms including headaches and dizziness. People with heart conditions may feel additional symptoms, such as chest pain.
• 100 ppm: Exposure for two hours or more can cause a headache, fatigue, and nausea.
• 150–200 ppm: Long-term exposure can lead to death.

How Many CO Detectors Do I Need?

• Recommendations for CO detectors are similar to those for smoke alarms. As a minimum, each home should have one CO detector on each floor, one in or just outside each sleeping area, and one in the basement. In homes where multiple bedrooms adjoin a common hallway, a single detector in the hallway can provide protection for all of the rooms. However, if the home has forced-air heat (with a conventional gas or propane furnace), carbon monoxide leaking in the furnace system can reach each room individually
• Therefore, it’s safest to include a separate CO detector in each bedroom or other sleeping areas.
• If other areas of the home, such as an attic or closed-in porch or sunroom, have combustion appliances or are used as sleeping areas, each of those spaces should have a CO detector. The same is true for a garage or outbuilding (greenhouse, garden shed, etc.) with a non-electric heater.