CO and CO2 – What’s the difference?

It’s easy to understand why people confuse CO-carbon monoxide and CO2-carbon dioxide. The names sound the same, they both are colorless and odorless gases, and at high concentration, both can kill you.

The media doesn’t help. Back in the old days, movies taught us that you could commit suicide by sticking a garden hose in your car’s tailpipe and window, then gunning the motor till the CO put you to sleep. Today they tell us the car’s tailpipe is a major source of the greenhouse gas CO2.

It’s important that you understand the difference:

About Carbon Monoxide

  • CO does not occur naturally in the atmosphere
  • CO is the result of oxygen-starved combustion in improperly ventilated fuel-burning appliances such as oil and gas furnaces, gas water heaters, gas ovens, gas or kerosene space heaters, fire places and wood stoves
  • CO is generated by any gasoline engine that DOES NOT use a catalytic converter
  • It is the most common type of fatal poisoning in many countries

CO Recommended Levels

  • OSHA limits long-term workplace exposure levels to 50ppm (parts per million)
  • Symptoms of mild CO poisoning include headaches and dizziness at concentrations less than 100ppm
  • Concentrations as low as 700ppm can be life-threatening

About Carbon Dioxide

  • CO2 occurs naturally in the atmosphere, and is required for plant life
  • CO2 is a natural byproduct of human and animal respiration, fermentation, chemical reactions, and combustion of fossil fuels and wood
  • CO2 is generated by any gasoline engine that DOES use a catalytic converter
  • CO2 poisoning is rare; however scuba divers have to watch out for it (the bends)

CO2 Recommended Levels

  • 385ppm is the current average on the planet
  • ASHRAE recommends a 1,000ppm limit for office buildings and classrooms
  • OSHA limits long-term workplace exposure levels to 5,000ppm
  • Drowsiness can occur at 10,000ppm – common in closed cars or auditoriums
  • Symptoms of mild CO2 poisoning include headaches and dizziness at concentrations less than 30,000ppm (3%)
  • At 80,000ppm (8%) CO2 can be life-threatening
Posted by CO2 Meter on August 27, 2009.
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