AirGradient Forum

Different PM2.5 readings in HA and on device [AG1 Indoor Kit]

Support
#1

Hi folks,

I set my indoor kit up, integrated it with Home Assistant and noticed that HA and the device display different values. I tried to do my homework and oh boy it turned out to be a deep rabbit hole.

It looks like the device displays raw, uncalibrated PM2.5 values (which are about 18 ug/m³ at my place). Home Assistant displays calibrated/compensated values (~12 ug/m³).

  • Is there a way to display compensated values on the device itself? I found that there is supposed to be the monitorDisplayCompensatedValues setting, I tried to change it to true via a PUT curl request, but it nothing happened, the device continue displaying raw/higher values.
    • I thought maybe connecting the monitor to the dashboard will resolve the issue but not only it also didn’t change anything, it appears that the dashboard too displays the raw PM2.5 value.
  • How can I make sure that the correct calibration settings are applied? Do I simply choose PM2.5 Calibration Formula corresponding to my batch (20250530) in the dashboard? Do I need to check Apply EPA Formula?
/config 
{
  "country": "AM",
  "pmStandard": "ugm3",
  "ledBarMode": "co2",
  "abcDays": 8,
  "tvocLearningOffset": 12,
  "noxLearningOffset": 12,
  "mqttBrokerUrl": "",
  "httpDomain": "",
  "temperatureUnit": "c",
  "disableCloudConnection": false,
  "configurationControl": "cloud",
  "postDataToAirGradient": true,
  "ledBarBrightness": 10,
  "displayBrightness": 20,
  "offlineMode": false,
  "monitorDisplayCompensatedValues": true,
  "model": "I-9PSL-DE"
}
/measures/current 
{
  "pm01": 6.33,
  "pm02": 16.5,
  "pm10": 18.83,
  "pm01Standard": 6.33,
  "pm02Standard": 16.5,
  "pm10Standard": 18.83,
  "pm003Count": 727.17,
  "pm005Count": 607.67,
  "pm01Count": 97.5,
  "pm02Count": 12.33,
  "pm50Count": 1.67,
  "pm10Count": 1.17,
  "pm02Compensated": 10.86,
  "atmp": 20.42,
  "atmpCompensated": 20.42,
  "rhum": 41.01,
  "rhumCompensated": 41.01,
  "rco2": 905,
  "tvocIndex": 100,
  "tvocRaw": 30886.17,
  "noxIndex": 1,
  "noxRaw": 18544.83,
  "boot": 35,
  "bootCount": 35,
  "wifi": -58,
  "ledMode": "co2",
  "serialno": "xxxxxxxxxxxx",
  "firmware": "3.4.1",
  "model": "I-9PSL"
}
1 Like
#2

Hi @withkittens! Welcome to the community!

If you switch the configuration source in HA to “cloud” or “both”, the settings (including calibration formulas) will be carried over to HA as well.

For guidance on applying batch correction formula and EPA formula, please refer to this thread: PM2.5 Calibration Formula - #9 by Altair_AirGradient

You should choose the corresponding correction formula for your batch and then apply the EPA formula on top.

1 Like
#3

Hey @Altair_AirGradient, thank you :purple_heart:

I will try to switch the configuration source to “both”.

I realized it was a mistake on my part as the documentation says this setting is on a single specific version (3.1.9) of the firmware only.