AirGradient Forum

Calibration Confusion

Components
#1

I am looking at purchasing and am confused by the calibration instructions.

This page states “For most applications, a single calibration before deployment is enough.” and “Without calibration, the sensors in the AirGradient monitor provide enough accuracy to give you an idea of the general pollution levels”. I only need general levels, this would be for home use, but these statements are implying that the sensors are NOT calibrated by default.

In contrast, on the product page it states that “Every sensor goes through a multi-step testing and calibration process to ensure the highest accuracy.” and that specifically the PMS5003 sensors are already factory calibrated.

Are the sensors calibrated or not? If they are already calibrated, wouldn’t my amateur calibration attempts “ruin” the factory calibration? I feel like I’m missing something.

#2

Hi @Mike,

The reason the UNDP toolkit mentions “calibration before deployment” is because the toolkit is aimed at large scale research network deployment. When you deploy tens or hundreds of devices in the field and need all of them to align very closely with each other, researchers typically co-locate them near a reference station for a few days. That’s about tightening reproducibility across the whole fleet. For normal home use, this is not necessary.

Every PMS5003 already has its own factory calibration, and on top of that we run all monitors through an additional calibration process before they leave our workshop. With the introduction of Test Report Version 2, these calibration factors are now tied to the device’s serial number, so each unit gets its own correction layer to ensure reproducibility. For home use, you don’t need to calibrate anything. The device is ready out of the box.