PM2.5 and PM10 values almost always the same?

Hi all,

I have received my O-1PS outdoor monitor and have integrated it into Home Assistant. What I have noticed is that its values are sometimes comparatively high, especially to our AirRohr (which we want to replace with the AirGradient due to flakiness).

In addition, the AirGradient seems to rarely differentiate PM2.5 and PM10 in our case. Is this expected? The image below shows values from both devices and a longer span of the AirGradient where PM2.5 and PM10 is always just within 1 or 2 µg/m3.

Is this expected? And if not, what can I do to recalibrate or resolve the issue?

Is it normal that AirGradient values are always rounded to a full integer?


Can you please inform on which firmware version you are running?

3.1.3 – The serial number is 84fce6…

A few pointers here:

  • PM10 is in general not very accurately measured by all low cost PM sensors. So I would not use that figure extensively. Smaller particles are more dangerous and should be the focus (PM1, PM2.5).

  • The Plantower sensor we use tends to overstate concentrations. It has been extensively tested by the US EPA and they developed a compensation algorithm that we tested and found to be working very well. This algorithm can be seen here:

We currently implement this algorithm on our dashboard and map.