VOC readings

We have a temtop sensor that we’ve been using for 3-4 months. lately my partner and I have been coughing etc and so we’ve been monitoring the air more (we have air purifiers and able to keep PMs pretty low).

I woke up this morning and saw VOC levels at 1.4 mg/m3 (all over house), which seemed insanely high. After opening windows we got it down to like .15 mg/m3.

I’ve heard this VOC sensor can be inaccurate / wear out, so I’m not sure how to take these data. Does anyone know if it just stops working over time, or become less sensitive or more sensitive over time?

It seems to be recording SOMETHING, but we don’t have any recent painting, staining, etc. or even new furniture other than a green guard certified crib, which I can’t imagine is filling the whole house. We don’t smell anything!

Only recent change I can think of is it getting cold outside and using the furnace…