Aquality32: A low-cost, open-source air quality monitoring device leveraging the ESP32 and google platform

We present AQuality32, an open-source air quality monitoring device designed to address the challenges faced by small research teams in accessing affordable and versatile air quality monitoring solutions. The device utilizes an ESP32 System on Module (SoM) and integrates sensors for CO₂ (SDC30 from Sensirion) and particulate matter (HM3301 from Seeed) measurement, along with temperature, relative humidity, and extensive sensing possibilities. It can be powered by a battery and is suitable for both stationary and on-the-go measurements. The paper details the hardware description, building instructions, programming, calibration procedures, and data collection setup for AQuality32. Validation experiments assess communication stability, geolocation accuracy, and environmental monitoring capabilities. The results demonstrate the device's reliability, affordability, and suitability for various applications in environmental sciences, public health, and indoor/outdoor air quality monitoring. The paper emphasizes the importance of robust solutions, openness, and easy documentation for widespread adoption and impact in air quality research and monitoring.