Carbon monoxide (CO) is a colorless, odorless and lethal gas. Because it is impossible for a person to detect carbon monoxide, CO is capable of killing you before you are even aware that you have a leak in your home. At lower levels of exposure, CO causes mild effects that are frequently mistaken for the flu. The symptoms associated with low level exposure include: nausea, fatigue, headaches, dizziness, and disorientation. However, the effects of CO exposure can differ greatly between people depending on overall health, age, and the concentration and length of exposure.
Sources of Carbon Monoxide
Kerosene and gas space heaters that are not vented to the outside; leaking furnaces and chimneys; back-drafting from fireplaces, gas water heaters, furnaces, and wood stoves; generators and other gasoline powered equipment; gas stoves; automobile exhaust from attached garages; and tobacco smoke. Incomplete oxidation during combustion in gas ranges, or gas and kerosene heaters that are not vented to the outside can cause very high concentrations of CO in indoor air. Old or poorly maintained and adjusted combustion instruments (such as furnaces and boilers) can be a serious sources, or if the flue is not sized correctly, disconnected, leaking, or is blocked. Bus, auto, or truck exhaust from attached garages, parking areas, or nearby roads can also be a source.
Health Effects Related to Carbon Monoxide
At low concentration, lethargy in people who are healthy and chest pain is persons with heart disease. At elevated concentrations, impairment of vision and coordination; confusion; nausea; dizziness; headaches. It can also cause flu-like symptoms that clear up after leaving the home. At very high concentrations, carbon monoxide is lethal. Acute effects are caused by the formation of carboxyhemoglobin in the bloodstream, which inhibits the intake of oxygen. At less excessive concentrations, reduced brain function, angina, and impaired vision may result.
Carbon Monoxide Concentrations in Homes
The average concentrations in homes that don’t have gas stoves vary from between 0.5 and 5 parts per million (ppm). Concentrations in homes that have appropriately adjusted gas stoves are typically between 5 and 15 ppm, and those with improperly adjusted gas stoves may have concentrations of 30 ppm or more.
Steps to Reduce Carbon Monoxide Exposure
It is important to make sure that all combustion devices are properly adjusted and maintained. Use of vehicles should be carefully managed in vocational programs and next to buildings. Added ventilation can be used as an added precautionary measure when high concentrations of CO are expected for a short time period.
- Consider purchasing a space heater with a vent when replacing an unvented one.
- Install and use an exhaust fan vented outside over gas stoves.
- Make sure that gas appliances are kept properly adjusted.
- Open the flue when a wood burning fireplace is in use.
- Use the correct fuel in kerosene heaters.
- Have a trained professional clean, inspect, and perform maintenance on central heating units on a yearly basis.
- Choose only wood stoves that are certified to meet EPA emission standards. Be sure that the doors on all wood stoves fit snugly.
- Installation of a carbon monoxide detector will also warn if the CO levels begin to reach elevated levels, so you can get out of the house and get fresh air.
