Understanding what “carbon monoxide levels” means may actually save your life one day. Carbon monoxide, or CO, is a poisonous gas that can kill you in large concentrations. Therefore, you should be aware of what high CO levels are and how to interpret the numbers associated with them. Carbon monoxide is present all over the world and is even in our atmosphere, but it is when the concentration becomes too high and the oxygen levels are imbalanced in proportion to it that this gas becomes a health risk.
Measuring CO Levels
CO levels are measured in ppm, or parts per million. For example, if the CO level was 1 ppm, it would imply that for every 1 million air molecules is 1 single carbon monoxide molecule. This would seem like it’s not a lot but for the fact that it only takes a relatively small amount of carbon monoxide to incapacitate a human being, or at least to cause him significant health problems.
CO, when absorbed through the lungs, mixes with hemoglobin to become carboxyhemoglobin. Thus, that is how CO poisoning is often determined – through measuring levels of carboxyhemoglobin in the bloodstream. Usually this is between 0% and 3% in normal conditions. For cigarette smokers who smoke two packs per day, it may be as high as 9%. Those who experience symptoms of CO poisoning usually have a carboxyhemoglobin ratio of 10-30%. When there has been a high concentration of CO, carboxyhemoglobin levels can be as high as 50%, causing seizures and death. Some victims after dying of CO poisoning will be found with levels as low as 30% or as high as 90%.
CO Levels in Different Settings
The atmosphere naturally has about 0.1 ppm of carbon monoxide in it. Homes may have a carbon monoxide level of 5 ppm due to the presence of fuel-burning appliances and devices. Other common CO-producing combustions include wood fires, which create 5,000 ppm CO, and car exhaust, which creates 7,000 ppm CO when undiluted.
Free Air vs Enclosed Spaces
Enclosed spaces with CO will definitely have higher levels of CO ppm, whereas open areas will dilute the concentration with oxygen. Of course, even outdoors there is plenty of combustion of fossil fuels contributing to the concentration of CO. High levels of CO in a major metropolis may be 15 ppm in the air, for example, which will not have a significant effect upon the health of the human body but is still not good for the lungs and cardiovascular system. In enclosed spaces, the concentration can quickly become deadly, so it is important to keep your home well ventilated – especially those rooms containing or near fuel-burning appliances.
CO Levels of Note
Generally, any level of carbon monoxide higher than 30 ppm warrants concern because chronic exposure can create long lasting health problems in the body. The Occupational Safety and Health Administration has set a limit on the workplace for CO levels, requiring that for long-term work exposure they must be less than 50 ppm. Over the period of 6 or more hours, a CO level of 35 ppm can cause headaches and dizziness. Increasing to 100 ppm or more will cause headaches and more symptoms in an hour or two. Any level over 100 ppm is dangerous to human health, and once you reach 800 ppm you’re approaching the level of coma and death. While a gas stove will burn at up to 15 ppm, a home wood fire will burn at 5,000 ppm of CO; this high CO level, which can kill you in 20 to 30 minutes, necessitates that you make sure your chimney is properly cleaned out to allow the CO a place to escape to.