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Carbon Monoxide (known commonly as its elemental composition CO) is a colourless, odorless, tasteless toxic gas and is a deadly asphyxiate at high levels. CO can be produced when imcomplete and improper buring of fossil fuels occurs.

Gas and oil heating systems, diesel and propane driven vehicles, floor polishers, forklifts, generators, fire pits and other related systems have the potential for harmful concentrations and are all around us at work and at play.

CO is measured in parts per million (PPM). Our air contains 79% nitrogen (N) and 20.9% oxygen (O2). If you happen to smell exhaust gases or fumes, CO is present.

Health effects of Carbon Monoxide

When carbon monoxide is inhaled into the lungs it bonds with hemoglobin in the blood, and forms carboxyhemoglobin (COHb). This condition displaces oxygen in the blood stream and effects all major organs and muscles. The condition can be fatal to some people sooner then others.

Chronic low levels of CO can compromise any health condition. At low concentrations CO can go undetected, and contribute to nagging illnesses and premature death. Healthy adults may show no ill effects to low-level concentrations and still complain of headache or a constant stuffiness that can worsen if undiagnosed.

Elderly people, small children and infants or anyone in poor health can experience affects much sooner than a healthy adult.

Respiratory problems, chronic heart disease, dizziness, vomiting, flu like symptoms, general weakness and confusion are all symptoms of CO poisoning. Pets can be more susceptible because of their faster metabolic rates.

Primary Source of Carbon Monoxide at Home and in the Workplace

  • Fuel-burning appliances such as furnaces, fireplaces, gas stoves and water heaters (especially those that are not properly vented or maintained) or when chimneys are blocked or dirty;
  • Idling vehicles in garages that are attached to homes or buildings;
  • Barbecues, grills, space heaters and other non-vented fuel-burning appliances that are designed for outdoor use; and
  • Tobacco smoke.

Source: Health Canada – Environmental Workplace and Health – Carbon Monoxide

Monitoring CO levels in buildings

Measurements of Carbon Monoxide are typically obtained from hand-held, stand-alone or comprehensive IAQ equipment. As CO is odourless and colourless its presence often goes undetected until symptoms arise, at which point it’s too late. It is critical to carefully monitor CO values at work and at home to ensure the values are within occupations exposure limits and residential indoor air quality guidelines respectively.

Carbon Monoxide Exposure Limits

The Carbon Monoxide short term exposure threshold is the same in both the home and the workplace. The TWA or Time Weighted Average is a one-hour average value which must not be exceeded to prevent the immediate health effects that may occur from exposure. This value is 25 ppm (parts per million). Prolonged exposure must also be considered, particularly in the home where longer periods of time are spent without departure. The Health Canada guidelines indicate a long-term exposure limited (24-hours) of 10 ppm.