Following the manual of the sensor “the autocalibration should be on for “indoor” units and off for others, with calibrations from time to time…”
The way it works looking at the data is that if the ppm is to low the sensitivity is increased, if its high the sensitivity is decreased, this happens every 24 hours.
With a outdoor sensor (like here in a city street) the variations are (very) big and causing a almost daily jump of the readings (70-120ppm in both directions).
Switching the autocalibration off and automatic calibration every month at a quit moment ?
Calibration always a tricky business….