Carbon monoxide (CO) is a gas that cannot be seen, smelled, or tasted. Often called a “silent killer,” it can build up to harmful levels without sensory warning.
Comparing Carbon Monoxide to Air
Carbon monoxide (CO) is slightly lighter than air. Air, a mixture primarily of nitrogen and oxygen, has an average molecular weight of about 28.8 to 29 g/mol. CO, however, has a molecular weight of approximately 28.01 g/mol, making it marginally less dense.
Behavior of Carbon Monoxide in Air
Despite being slightly lighter than air, carbon monoxide does not accumulate in distinct layers. Instead, it mixes readily and evenly with the air due to natural processes like diffusion and convection. Diffusion is the spreading of gas molecules, while convection involves fluid currents. This allows CO to spread throughout a room or building, rather than remaining in specific high or low areas.
Understanding Carbon Monoxide Hazards
Carbon monoxide is produced by the incomplete burning of fuels such as natural gas, propane, wood, coal, and gasoline. Common household sources include malfunctioning furnaces, water heaters, gas stoves, and fireplaces. Portable generators, charcoal grills, and vehicles running in enclosed spaces like garages also release CO.
When inhaled, carbon monoxide enters the bloodstream and binds to hemoglobin, the protein in red blood cells responsible for carrying oxygen. CO has an affinity for hemoglobin that is 200 to 250 times greater than that of oxygen, forming carboxyhemoglobin (COHb). This binding prevents hemoglobin from transporting oxygen effectively, leading to oxygen deprivation in the body’s tissues and organs.
Symptoms of CO poisoning can resemble the flu and include headache, dizziness, weakness, nausea, and vomiting. More severe exposure can lead to chest pain, confusion, shortness of breath, and loss of consciousness. In extreme cases, prolonged exposure can be fatal.
Safeguarding Against Carbon Monoxide
Install carbon monoxide detectors as a safety measure. Place them on every level of a home, especially near sleeping areas and attached garages. Follow manufacturer instructions for installation and maintenance, including monthly testing and annual battery replacement. Most detectors have a lifespan of 5 to 10 years and should be replaced accordingly.
Preventing CO buildup involves proper ventilation and regular maintenance of fuel-burning appliances. Furnaces, water heaters, and other gas appliances should be inspected annually by a qualified professional. Never operate charcoal grills, portable generators, or vehicles indoors, even with open windows or garage doors, as CO can quickly accumulate to dangerous levels. Keep chimneys and appliance vents clear of obstructions to prevent CO from backing up into the home.