# Natural air-CO2 deviations in the troposphere

I'm working on a room air quality management algorithm, and many sensors seem to respond with $$\small\mathsf{CO_2}$$ measurements of as little as 200 ppm. Obviously a sensor giving off this value will be broken or badly calibrated, but I'm wondering about what deviations from the "average" $$\small\mathsf{CO_2}$$ content of the atmosphere (400-410 ppm) could be normal, for example, because the building is located in an area with little industry, vehicles and with lots of lush vegetation. Any information would be appreciated, since I, so far, had very little luck in acquiring decent sources on this issue.

• Typical CO2 levels chart in this article. Nov 12 '19 at 2:36
• That's useful, thanks. However, in order to detect sensor malfunctions or bad calibration, I would be more curious about the other end of the spectrum ... areas of "low" co2 concentrations Nov 12 '19 at 8:24
• I found this paper which seems to show in Figure 5 a few ppm decrease in forests. Nov 12 '19 at 16:44
• Just what I was looking for. You can put this down as an answer. Nov 12 '19 at 17:10