Colourless, odourless and dangerous
Carbon dioxide is a colourless, odourless gas made up of one carbon atom joined to two oxygen atoms. This means it has the chemical formula CO₂. It can sometimes be confused with carbon monoxide where one atom of carbon is joined to one atom of oxygen, which has the chemical formula CO. Both gases are bi-products of the combustion process when hydrocarbons are burnt. Carbon dioxide always occurs when there is plenty of oxygen present and the combustion is described as complete. Indeed it is possible to burn carbon monoxide in air and convert it to carbon dioxide.
It is relatively common knowledge that people breathe it out, trees breathe it in and it’s the fizz in beer and soft drinks. This can lead to the belief that carbon dioxide is relatively benign, it is not! It was long thought that the greatest threat from carbon dioxide occurred if it displaced the oxygen present to create an atmosphere in which people would suffocate, however, carbon dioxide is toxic and can have a damaging effect on health long before it would have displaced enough oxygen to asphyxiate someone. It has a long-term workplace exposure limit of 5000 parts per million (0.5%).
Image by Mikael Häggström, used with permission
Carbon dioxide exists in the atmosphere currently at 412ppm; however, it has been consistently growing year by year and is considered an important greenhouse gas. This means that its molecules in the atmosphere absorb radiation, keeping the Earth warmer than it would otherwise be.
The carbon oxygen bonds in CO2 absorb infra red radiation and this is the principle used in the NDIR sensor in the NEW Senko iGas personal carbon dioxide detector, which provides simple and affordable protection against the dangers of carbon dioxide poisoning.
