1. How to monitor
indoor CO2
Presented by
Hibouair.com

2. CO2 is a gas and cannot be monitored with
typical light-scattering laser sensors used to
measure PM.

3. Instead, CO2 is best measured with sensors that use
infrared (IR) light to estimate the number of CO2
molecules in ambient air

4. Here’s how this works

5. Ambient air passes through a CO2
sensor assembly made up of an IR light
source, reflective gas cell, and IR light
detectors.

6. IR light shines onto CO2 molecules that
pass through the assembly. The CO2
molecules absorb much of this light.

7. The remaining light that isn’t absorbed
by CO2 molecules passes through to
detectors.

8. IR light detectors calculate the change
in IR wavelengths from what was
produced by the IR light source to what
remains after CO2 absorbs the IR light.

9. The change in wavelength indicates the
concentration of CO2, which is
converted to a ppm reading

10. A standalone CO2 sensor may
indicate the presence of elevated
indoor CO2 and meet basic
CO2 monitoring requirements
for workplaces and schools.

11. A study published by the ACS
suggests that indoor CO2 levels
may be one tool to help

12. For More
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