My A3 has developed a new trick. It seems, on some of the reboots, it turns off the PM sensor. See attached PM graph. I am pretty sure it is powering down the PM sensor because the “floor” of the noise graph drops by about 3 dB when the PM readings go to zero (see second graph). There are some minor effects on the other sensors too.
PM was shut off for quite a few hours yesterday and went off again today too.
If there is no technical reason for this, I think I am reaching the point where I want to send this one back for exchange or refund.
I checked it now and it seems the PM sensor is having some issues as it shows max values on all 3 channels. Unlikely there is something this bad in air, unless you put your A3 in a box filled with smoke.
I will get back to you on email for detaisl on how to get your unit replaced.