One of the most common questions we receive at CO2Meter is, “What is PPM?” The abbreviation PPM stands for parts-per-million and is a crucial measurement when monitoring carbon dioxide (CO2) levels for indoor air quality and workplace safety.
What does ppm mean?
Parts-per-million (PPM) is a measurement that indicates the concentration of a substance within a solution or gas, expressing the number of parts of a specific substance per one million parts of the total mixture.
For example:
1. A cleaning solution with 100 PPM of hypochlorous acid means there are 100 milligrams per liter of that chemical in the solution.
2. A methane gas concentration of 2% equals 20,000 PPM, while 2 PPM of methane means 2 molecules per million air molecules.
Why is CO2 measured in ppm?
We tend to measure CO2 in "ppm" because it is the easiest way to measure something that is both colorless, odorless, and invisible to the human eye. CO2 can further be measured by the number of CO2 molecules per million molecules of air.
This is important because too high of CO2 levels or ppm indicates when a room or confined space should be ventilated and prevent overexposure of CO2 levels from occurring. When you think about the Health and Safety Executive's (HSE) approved code of practice, it states 1000ppm is equivalent to about 10 liters per second, per person. For any level consistently higher than 1500ppm in a occupied room indicates poor ventilation.
When it comes to safe CO2 levels and workspaces, there are different exposure limits that must be adhered to in order to prevent negative health effects from occurring.
How do you measure CO2 ppm?
In order to measure carbon dioxide, a CO2 sensor or monitor is typically used. One of the most common types is the NDIR non-dispersive infrared sensor. It is popular due to its long life-span, speed, and low cross-sensitivity to other gases.
An NDIR CO2 sensor works by measuring infrared light in air sample. This amount of infrared light is absorbed by the molecules of carbon dioxide that are proportional to the number of CO2 molecules in the air sample. This allows the sensor to measure the amount of CO2.
For more information on CO2 measurement range and accuracy, read more here.
What PPM of CO2 is toxic?
For those producing, using, or working around hazardous CO2 levels when exposed to levels above 5,000 ppm for many hours serious injury can occur. For instance, higher levels of CO2 can cause asphyxiation as it replaces oxygen in the bloodstream to concentrations around 40,000 ppm which is immediately dangerous to life and health.
Safe CO2 PPM Levels in Indoor Spaces
Here are the general guidelines for CO2 PPM Levels:
Carbon Dioxide (CO2)
| 250-400 ppm |
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| 400-1,000 ppm |
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| 1000-2,000 ppm |
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| 2000-5,000 ppm |
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| 5,000 ppm |
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| >40,000 ppm |
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What PPM of CO2 is Dangerous?
High CO2 PPM levels can be hazardous:
- 5,000 PPM: Prolonged exposure may lead to health risks, including headaches and reduced oxygen intake.
- 40,000 PPM and above: Immediately dangerous to life and health, leading to severe oxygen deprivation, brain damage, or death.
Why Monitoring CO2 PPM is Essential?
Regular monitoring of CO2 PPM levels helps:
- Ensure proper ventilation
- Reduce airborne illness transmission risks
- Improve productivity and well-being
- Maintain regulatory compliance for workplace safety
Ready to Monitor Your CO2 PPM Levels?
Using a CO2 monitor allows you to take proactive steps to improve indoor air quality while creating a healthier environment for your employees, customers, and family.
CO2Meter offers a full range of CO2 sensors, monitors, and indoor air quality solutions designed for your specific needs whether for commercial, industrial, or residential environments.
Contact us today to learn more about CO2 measurement solutions or browse our CO2 monitors to start improving your indoor air quality and safety.
