Carbon Monoxide and Indoor Air Quality

Over the last two weeks, there have been several news stories related to high concentrations of carbon monoxide in indoor air leading to death. On March 23, 2017, Global News published an article, "16 Mandarin restaurant employees in Scarborough hospitalized with carbon monoxide symptoms". On April 1, 2017, CTV featured an article, "Hotel carbon monoxide leak kills child, sickens others in Michigan", about a carbon monoxide leak at a hotel that killed one child and made approximately twelve other people ill. On April 3, 2017, CBC News published an article, "A life off the grid: Idyllic then deadly" about four people killed from carbon monoxide poisoning in British Columbia as a result of carbon monoxide leaking from a propane-powered hot water tank. On April 2, 2017, the Globe and Mail featured an article, "Most Canadians unprotected against carbon monoxide, fire chiefs say".

Carbon monoxide is an odourless, colourless, tasteless gas that is a byproduct of fuel combustion, irrespective of the type of fuel used. Appliances or motor vehicles that produce carbon monoxide become a risk when there is poor ventilation, and the carbon monoxide accumulates to dangerous levels. At low concentrations of carbon monoxide, adverse health effects may be experienced including tiredness, headaches, muscle weakness or shortness of breath. At high concentrations or when exposed to low concentrations of carbon monoxide over time, symptoms may include dizziness, chest pain or difficulty thinking.

Carbon monoxide combines with the oxygen-carrying sites on hemoglobin in the blood, with an affinity 210 to 240 times higher than that of oxygen. The resulting carboxyhemoglobin is unable to carry oxygen. Occupational health and safety codes recommended a maximum 8-hour exposure limit of 25 ppm.

In order to reduce the risk of exposure to high levels of carbon monoxide in indoor air, the following actions are recommended:

• Install CSA-certified carbon monoxide detectors in indoor spaces and test detectors regularly
• Ensure that appliances are well-maintain and regularly inspected by a professional
• Be vigilant for any signs of cracks, leaks or blocked vents in appliances that combust fuel
• Do not idle vehicles in the garage, even when the garage door is open
• Avoid smoking indoors
• Ensure that homes and buildings are well-ventilated.