Development of a novel low-cost automated flux chamber for real-time monitoring of VOCs emissions at contaminated sites

This study introduces an innovative, low-cost static flux chamber for real-time monitoring of volatile organic compound (VOC) emissions at contaminated sites. Compared to traditional static flux chambers, the developed system is fully automated, eliminating the need for continuous operator intervention in the field. The cylindrical stainless-steel chamber (6.28 L) is equipped with internal sensors for temperature, pressure, and humidity, and a low-cost PID sensor for VOC detection (0.001-40 ppm). VOC flux is determined over 10 min measurement cycles, with two micro diaphragm pumps purging the chamber to reset concentrations. An Arduino Uno microcontroller manages the system, enabling local data storage (SD card) and a LoRa module to send real-time data to the cloud using IoT systems. Powered by a 12 V battery, rechargeable via a photovoltaic panel, the system ensures continuous operation. The prototype costs less than 1.5 k, significantly cheaper than commercial devices. Accuracy and repeatability were assessed through lab-scale emission tests under dynamic conditions using various aliphatic and aromatic VOCs. Results closely matched those from a commercial gas analyzer and a Comsol Multiphysics numerical model, confirming the system reliability. These findings support its potential as a cost-effective alternative for continuous VOC monitoring at contaminated sites.