Enviro+ Oxide Level slow climb

Back to the oxide sensor topic I now have full day of results without any interruptions.

The huge peak that is well over 100K is from cooking four rhubarb and ginger cakes in a gas oven.

One curious pattern I have noticed is all three gas sensors drift up over night and then fall in the morning when the central heating comes on for about 1/2 an hour. While I know temperature affects them it should affect the oxide sensor in the opposite direction. I.e. when it is cold its resistance gets lower. This is apparent when the program is stopped for a short time, oxide drops and the other two rise.

The other things that are changing is relative humidity and light. The gas sensors seem very sensitive to relative humidity but the two step response in the morning seems to indicate a strange combination of temperature and humidity.

The other odd thing is I can see why the temperature rise causes a fall in relative humidity but why does it rise again shortly afterwards? And why does it fall over night when temperature is actually falling. Is it in fact my presence in the room that is raising the humidity when I arrive with my morning coffee?

It is had to separate real physical changes from senor instability!