AirGradient One vs Open Air reading differences

[Cubus]

Hello there,

I just received the Open Air (O-1PST) to compliment my One (I-9PSL).
Both shipped pre assembled and calibrated.

Both are running latest 3.1.3, I believe as it’s not clear to me how to check it. I did perform flashing procedure that concluded with success message.

They’re physically right next to each other with Open Air hanging and airflow to the bottom unobscured.
I let the Open sensor “settle” for about 12 hours.

What surprised me are large differences in readout of PM sensors and humidity.
Right next to both sensors is my T9 thermostats and was reading 59% humidity at the time of taking the screenshots.

Is this normal or expected. It’s quite disappointing to see such high differences.

Thanks for feedback!

[Achim_AirGradient]

Due to the weatherproofness of the outdoor enclosure we need to deploy correction algorithms for outdoors.

You can read more here:
https://www.airgradient.com/documentation/correction-algorithms/

These should work quite well once the monitor is mounted outdoors and runs for a few hours.

Then you shouldn’t see this much of a deviation anymore.

[Achim_AirGradient]

Additionally we want to look into the PM thing. Can you please send us a support message through the website with your Place ID and serial number?

[Achim_AirGradient]

Just an update that we currently switched off the RH compensation formula on our dashboard because we see differing data from some of the PMS5003T relative humidity sensors. We are investigating this.

[Cubus]

Thank you for looking into this!

[JanPieter]

(Since my question seems related to this, I’ll add to this topic instead of opening a new one.)

I received my new sensors yesterday. First: they look great and the discovery by and the integration with Homey went absolutely flawlessly!

I put both on a chair for some hours to compare sensor values between the inside and outside sensor. And I did a manual 400ppm CO2 calibration near an open window (now closed).

I’m mostly interested in comparing humidity and temperature values. It seems the indoor sensor shows almost the same values as my Honeywell room thermostat and a cheap humidity sensor. But the outside sensor differs quite a lot. Also the PM values are not the same.

Does the outside sensor maybe need to be mounted upright to measure correctly? I thought there was a small fan inside to blow the air through?

Any advice to increase the accuracy? Am I doing something wrong? Before I mount the sensors in their intended and separate places, I’d like to be sure they are (kinda) accurately showing the same values.