Just received my Airgradient One and noticed it was reporting an outdoor ambient CO2 level of 320 ppm when my area is at about 440 ppm. I used the “Request CO2 calibration” feature in the dashboard to bring the reading up to 400 ppm.
Is there a way to set the baseline CO2 level to 440 instead of 400? If I have to learn how to do it by modifying source code, that’s fine, I just want to know if it is possible.
Thank you.
The calibration feature is built into the sensor itself.
Best you could do is to add an offset to always add 40 to whatever the sensor report.
But CO2 varies pretty significantly through the day and seasons, so you would have to know exactly when outdoors is 440 according to reference devices to calibrate yours.
I personally would just leave it as factory
Hello @Darknyte , just out of curiosity - what is your current altitude in respect to sea level?
Asking as I’ve observed something similar on both my indoor and outdoor monitors (initial values quite below 400ppm), and in my case the explanation was rather my altitude.
If that’s your case too, I’d just like to mention that the calibration offset would not be enough for correcting the sensors readings - even if you set the target value to be 440 ppm.
We’ve had a specific discussion on this topic here: Altitude compensation for CO2
(But if you’re at or close to sea level, then my comment above doesn’t apply)
Thanks for your thoughtful response, I will leave as-is. I have enough information to know when to open a window.
Altitude is about 110m above sea level. Appreciate the response, your comment is helping me explore new areas that I knew nothing about.
Ah ok, I think at 110m the impact should be minimal and wouldn’t explain the initial difference you observed.
In general I think it’s difficult to set any specific CO2 baseline level because CO2 could also drop below the current average levels eg when nearby plants produce a lot of oxygen.