Curious if anyone has noticed any discrepancy with PM 2.5 readings. We had a Temtop M10 for over a year and our PM 2.5 readings were always down to 1-2 with our air purifier running. Unfortunately the M10 was dropped and damaged, so we went ahead and bought the Temtop M1000 as a replacement. It arrived about two weeks after we stopped using the other one, and with this one we never see the PM 2.5 drop below 4.5. It seems to hover mostly around 5-6, even in the bedroom with the door closed and the HEPA running four hours.

Is there another monitor for PM 2.5 that provides decent accuracy? I am surprised the newer monitor reads higher, there is nothing really different about the environment.