Carbon Monoxide

Carbon Monoxide (CO) is an odorless, colorless gas that is a by-product of the incomplete burning of fuels. Carbon monoxide is produced when fossil fuels are burned, from cigarette smoke and from human and animal breathing.

Outside, the principal source of CO pollution in most large urban areas is the car. It adversely affects human health at only a few parts per million and causes death at 250 parts per million (250 ppm). Since CO is a relatively unreactive gas in the absence of indoor carbon monoxide sources, the indoor air concentration is the same as the concentration of ventilated or infiltrating outdoor air. However, when indoor sources exist, the CO inside the home can be significantly higher and thus it is a very important pollutant to measure.

Average levels in homes without gas stoves vary from 0.5 to 5 parts per million (ppm). Levels near properly adjusted gas stoves are often 5 to 15 ppm and those near poorly adjusted stoves may be 30 ppm or higher.

Identifying sources

There are numerous sources of CO around the home. These sources include poorly installed and maintained heating systems, leaking chimneys, fireplaces, gas cookers, tobacco smoke, and other powered equipment; for example, car exhaust from attached garages. However, CO can be easily reduced from all of these sources and poisoning is easily preventable. Here are some precautions that can be taken:

• Do not use the oven of a gas kitchen stove for heating
• Avoid use of charcoal grills and hibachi pots indoors for cooking or to eliminate the chill in a room or closed garage. They give off CO fumes, even when no glow is visible in the coals
• Make sure that fuel-burning equipment is installed by qualified, licensed or trained persons. Such installation should conform to all local codes and standards
• Provide a constant supply of fresh air for safe burning of fuels. This can be done by leaving a window slightly open
• Provide for the positive venting of combustion gases to the outside. This can be accomplished by vent or flue pipes, exhaust systems, etc
• Heating systems, water heaters, kitchen cookers and other fuel-burning devices should be thoroughly inspected and maintained at least once a year by a qualified person
• Do not idle the car inside garage
• Never run any internal combustion engine equipment, such as a powered lawnmower or generator, in an enclosed space such as a closed garage. Always start it outside or with the door open

Medical Effects

The percentage of haemoglobin inactivated by CO depends on the amount of air breathed, the concentration of CO in air, and length of exposure. The initial symptoms of CO poisoning are similar to the flu. They include fatigue, dizziness, irregular breathing, cherry red lips, nausea, headache, paleness, and coughing.