A colorless, odorless gas that is formed from incomplete fossil fuel combustion or when something is burned incompletely. CO is toxic to all humans and animals, and is the most commonly inhaled poisonous substance.
Carbon Monoxide is predominately generated from automobiles idling in closed areas. Other sources include: gas appliances (furnaces, stoves and dryers), fireplaces that are blocked, charcoal grills used as inside heaters and smoking.
CO affects the central nervous system (CNS) in both humans and animals by inhibiting the uptake of oxygen by the body. Oxygen is normally absorbed into the bloodstream by binding to an oxygen carrier (hemoglobin). When CO enters the body, the oxygen carrier wants to carry CO rather than oxygen (in fact CO is absorbed 240 times more readily than oxygen by hemoglobin).
Provincial Guidelines:
Due to the nature of human generated CO, there are a number of things we can all do to minimize CO in the atmosphere:
Occupational Health and Safety Act (Alberta – AR 393/88 Chemical Hazards Regulation)
| Concentration (ppm) | Exposure Time | Human Symptoms and other Effects |
| 0 - 1 ppm | - | Normal background levels |
| 5 ppm | 8 hour | Alberta ambient air quality guideline for 8 hours |
| 9 ppm | - | Maximum allowable concentration short term in living area (ASHRAE) |
| 13 ppm | 1 hour | Alberta ambient air quality guideline |
| 25 ppm | 8 hour limit | Maximum exposure in the workplace (Time Weighted Average) |
| 50 ppm | - | Maximum exposure allowed (OSHA) in the workplace. |
| 200 ppm | 15 minutes | Mild headache, fatigue, nausea and dizziness |
| 400 ppm | 3 hours | Serious headache - other symptoms intensify and life threatening after 3 hours |
| 800 ppm | - | Dizziness, nausea and convulsions - unconscious within 2 hours and dead within 2 to 3 hours |
| 3200 ppm | - | Headache, dizziness and nausea - death within 1 hour |