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Carbon dioxide (CO2) is an odourless, colourless gas that can have serious health consequences. Carbon dioxide is produced when people and other animals exhale, and when fossil fuels are burnt, such as the engines in cars running or coal burning. As carbon dioxide exists naturally in the atmosphere, people don't usually think of it as a deadly gas, but it can be fatal.
Carbon dioxide is present in natural air at a quantity of approximately 0.035 per cent. When you are exposed to a low level of carbon dioxide, around 1.5 per cent, you will begin having physical and mental issues. But it can be difficult for you to figure out what is going on. The initial symptoms include dizziness and a change in breathing.
When you are in an area with a moderate level of carbon dioxide, ranging between 5 per cent and 9 per cent, you will feel the effects of the gas relatively rapidly. You will be very dizzy and start sweating. You will have a headache, and your heart rate and blood pressure will increase. Your mental capabilities will start to decrease, and you will feel confused and disoriented. Thinking rationally is nearly impossible, and you may not be able to figure out what to do about what you are experiencing.
If you are exposed to a high concentration of carbon dioxide, between 10 per cent and 15 per cent, it is potentially life-threatening. First you will get dizzy and then experience nausea and/or vomiting. It will become difficult to hear and hard to see, and your mental performance will be compromised. It won't be long before unconsciousness sets in. If you are not immediately removed from the exposure area, a slow and painful death is likely to occur.
If you are exposed to a level of carbon dioxide that is 20 per cent or higher, death is imminent. You will rapidly fall unconscious or into a coma. Convulsions are likely to occur. Death will follow, usually by asphyxiation, because the CO2 prevents blood from carrying oxygen into the bloodstream. This can happen in a matter of minutes.
Long-term exposure to low levels of carbon dioxide can affect the human body. Studies have shown that side effects include an imbalance in the blood, circulatory system issues during exertion, flushed skin, lower blood pressure, an increase in lung dead space, a lack of ability to be attentive and an inability of the body to effectively use oxygen. Over time, performance levels will decrease, and erratic, abnormal behaviour will set in.
- Aerias, Air Quality Sciences: Carbon Dioxide: A Common Indoor Air Pollutant
- Canadian Centre for Occupational Health and Safety: Health Effects of Carbon Dioxide Gas
- U.S. Department of the Interior, Bureau of Land Management: Health Risk Evaluation for Carbon Dioxide (CO2)
- U.S. Department of Energy, National Energy Technology Laboratory: Human Health Risk Assessment of CO2
- Thomas Northcut/Photodisc/Getty Images