The sensors in the Atmocube have automatic self-calibration/cleaning and data normalization algorithms/protocols that ensure long-term stability without the need for any manual action from users. The manufacturer datasheets for all the sensors in Atmocube and detailed specifications can be found at: Sensor Accuracy and Technical Specifications

The CO2 sensor is a photoacoustic technology based sensor that includes an automatic self-calibration (ASC) algorithm, which assumes exposure to clean outdoor air (400 ppm) at least once per week to maintain optimal accuracy. The automatic calibration compensates for potential drift over time due to environmental factors.

Additionally, the sensor integrates an onboard temperature and humidity sensor, which continuously measures and compensates for temperature and humidity effects, ensuring stable and reliable CO2 readings.

To ensure maximum accuracy:

The PM sensor does not require factory calibration because the measurement principle is based on laser scattering. Verification is performed at the stage of manufacturing with a 3% atomized KCI solution (Potassium Chloride). Deviation to a reference instrument is verified in end-tests for every sensor after calibration. The PM sensor has an automatic fan-cleaning procedure that is triggered periodically following a defined cleaning interval. For more details on sensor calibration and long-term drift, please refer to: PM Sensor Specification Statement

The VOC sensor is a metal oxide (MOx) or chemiresistive sensor that works on the principle of measuring the resistance of VOC gasses present in indoor environments in proportion to the logarithm of the resistance of the MOx material. It has an automatic calibration procedure where it resets the baseline to the cleanest air measured over a period of time. For more details on how the sensor works, please refer to the following resources:

What is a metal oxide (MOX) sensor?

Compliance of the VOC Sensor with Green Building Standards

The CH20 sensor is an amperometric electrochemical sensor that works on the principle that formaldehyde molecules pass through a membrane to react with water molecules in the electrolyte to release carbon dioxide and generate an electric current. The concentration of formaldehyde is determined by measuring the magnitude of the electric current. As the sensor is based on a chemical cell, it doesn't require calibration. The electrolyte is very selective to HCHO molecules. A baseline isn’t required, as the drift can be neglected. The annual drift is specified in the sensor datasheet - long term drift is <5 ppb or <5% of measured value, whichever is larger - per year.

In addition to built-in sensor algorithms, external normalization and compensation algorithms are used to properly interpret/compensate for readings, depending on the changes in the environment (temperature, humidity, pressure, etc.).