Investigating indoor and outdoor carbon dioxide concentrations with Vernier CO2 Gas Sensor



Carbon dioxide is a colourless and odourless gas. It has many important uses.

It is the fizz in soft drinks, beer, and sparkling wines.

Carbon dioxide is released by baking powder of yeast to make cake batter rise. It is used in some fire extinguishers.

Dry ice is solid carbon dioxide.

Carbon dioxide is a product in cellular respiration and a reactant in photosynthesis.
But too much of a good thing, like carbon dioxide, can be bad.

Carbon dioxide concentration is a surrogate for indoor pollutants that can cause drowsiness, headaches, and lower activity levels.

CO2 levels less than 600 ppm are desirable, and levels greater than 1000 ppm are generally considered indicative of inadequate ventilation. Levels of 2,500 ppm or greater can cause headaches. (from Vernier website)


FRESH AIR COMPOSITION (image from Science in school, winter 2008)

EXHALED AIR COMPOSITION (image from Science in school, winter 2008)

How does CO2 concentration in an occupied classroom vary with time?

How much is CO2 concentration inside the classroom different  from outside?

How does CO2 in an occupied classroom vary if we open the windows for 10 minutes?




Measure in a Coletti school classroom on 14th of February


CO2 Concentration

Classroom   occupied   for 30  minutes

1950 ppm

Classroom after opening the windows for 5 min

800 ppm

Outside (on the windowsill)

600 ppm