1. What is Carbon Monoxide (CO)?

  • Carbon monoxide is a colorless, odorless, tasteless gas

2. Where does carbon monoxide come from?

  • CO gas is produced by burning gasoline, wood, propane, charcoal or other fuel 

3. Who's at risk of carbon monoxide poisoning?

Everyone is at risk. Because you can’t see, taste or smell it can kill you without being aware of its presence. CO poisoning is particularly dangerous for people who are sleeping or intoxicated. 

Exposure to low levels of CO may be particularly dangerous for:

  • Unborn babies. Fetal blood cells take up carbon monoxide more readily than adult blood cells do. This makes unborn babies more susceptible to harm from carbon monoxide poisoning.
  • Young children take breaths more frequently than adults do, which may make them more susceptible to carbon monoxide poisoning.
  • Older adults. Older people who experience carbon monoxide poisoning may be more likely to develop brain damage.
  • People who have chronic heart disease. People with a history of anemia and breathing problems also are more likely to get sick from exposure to carbon monoxide.
  • Those in whom carbon monoxide poisoning leads to unconsciousness.  Loss of consciousness indicates more severe exposure.

    4. Why is Carbon Monoxide dangerous?

    • Carbon monoxide is harmful when breathed because it displaces oxygen in the blood and deprives the heart, brain and other vital organs of oxygen. 
    • As you inhale CO, it quickly bonds with hemoglobin and displaces oxygen molecules. This produces a toxic compound in your blood called carboxyhemoglobin (COHb).
    • Carboxyhemoglobin produces flu-like symptoms such as headaches, fatigue, nausea, dizzy spells, confusion, and irritability. Since symptoms are similar to the flu, CO poisoning is overwhelmingly misdiagnosed.
    • As the time and levels of exposure to COHb rise, victims can suffer more extreme symptoms such as vomiting, eventual loss of consciousness, and eventually even brain damage or death.

    5. How do standard CO monitors work?

    They are built to meet the standards:  Retail brand carbon monoxide monitors are designed to meet governing standards such as UL Standard UL2034, or related Canadian standard CSA 6.19). These standards are primarily designed to protect healthy adults from high levels of CO so don't require an alarm for concentrations below 70 PPM (Parts Per Million).

    They must adhere certain alarm test points and minimum exposure times:

    • 0 – 29 PPM – The detector must remain silent. If it has a digital display, it must show a zero reading.
    • 30 PPM – 69 PPM – If the carbon monoxide level remains in this range for a minimum of 30 days, the audible alarm may sound. If the unit has a digital display, it should display the CO level provided it is 30 ppm or higher.
    • 70 PPM – 149 PPM – The alarm must sound for between 60 – 240 minutes.
    • 150 PPM – 399 PPM – The alarm must sound if the CO level stays in this range for between 10 – 50 minutes.
    • 400 PPM + – The alarm must sound if the CO level remains at or above this level for between 4 – 15 minutes.


    All alarm and display levels listed above have a minimum and maximum time window in which it can alarm. For example the minimum audible alarm test point of 70PPM has a range of between 60 – 240 minutes, meaning that the unit can take upwards of 4 hours before alerting the occupants of this potentially serious health hazard. 

    How they measure CO concentration: All CO monitors use digital devices called analog to digital converters (a/d) to measure CO concentrations. A typical a/d converter will measure with a resolution equal to the maximum value divided by 256. For example, if an alarm has a maximum display value of 1000 PPM, then the resolution will be 1000/256 or approximately 4 PPM.

    With such a wide range of detection (70 - 1000 PPM) these monitors can be off by +/-10 PPM.  This means that for an actual gas concentration of 15 PPM, it might be displayed as 25 PPM, or it might not display anything at all!

    5. Why are CO EXPERT's low level CO monitors different?

      The key purpose of our low level CO monitors is to as accurately as possible alert you of a potential issue BEFORE a serious situation can develop.

      Our technology:  Our monitors use the same electrochemical sensor technology found in professional carbon monoxide analyzers used by First Responders and HVAC Technicians, often costing thousands of dollars.

      Accuracy of our monitors: We focus on accuracy in low level readings, so we limit our display range to between 5PPM and 50PPM. So using the same a/d converter as above, the resolution will be 50/256 or approximately 0.2 PPM.Our monitors are all calibrated at 3 different “Low Level” CO gas concentrations, and are tested and certified for display accuracy at 3 different “Low Levels”.

      Display levels: Monitor starts to display CO levels as low as 7 PPM

      Audible alarm signal:  Increases in urgency with rising CO levels:

      • 4 beep alarm pattern repeats 1 per min at lowest alarm threshold
      • Alarm pattern repeats 1 per 30 seconds at 35 PPM
      • Crisis alarm – pattern repeats 1 per 20 seconds at 50 PPM