Different PM readings

#1

Hi, I have 3x ONE V9. The first one was from January 24 and was fully assembled; the other two were purchased as kits and arrived today. All run 3.1.3.

The old one (assembled) shows slightly higher PM1/2.5/10 readings and a much higher PM0.1 count (see the attached screenshot). First, they were in the same room, then I put them outside next to each other to calibrate CO2 and took the attached screenshot.

When they were indoors, and I blasted our air purifier to the max, all µg/m3 PMs went to zero after a few minutes, but PM0.1 counts were around 150 on the new ones and 400+ on the old one.

Is this normal? Do I have different sensors, or is the assembled one somehow calibrated? All the other sensors show identical readings.

Thanks!

Screenshot 2024-06-28 at 22.17.02
Screenshot 2024-06-28 at 22.17.022920×638 53.9 KB

#2

Our understanding from the manufacturer is that the pm0.3 count are uncalibrated numbers whereas the ug/m3 figures are factory calibrated.

So the count numbers should not be compared between different sensor modules.

1 Like
#3

Got it, thank you for the quick response.