IoT for CO2 Surveillance in Volcanic Soil Using a Web-Based Monitoring and the LI-830 sensor. Study case in Cerro Pacho, El Salvador

El Salvador is a country with significant volcanic activity. Volcanoes emit a variety of gases from their slopes and their craters. In order to assess the risk of an eruption, it is therefore essential to monitor the presence and intensity of these gases, mainly $CO_{2}$, in the craters and slopes of a volcanic region. The Ministry of the Environment and Natural Resources monitors $CO_{2}$ gas in volcanic activity areas in El Salvador. This government agency has LI -830 sensors for this purpose. However, this equipment is over 15 years old and lacks wireless, storage, and mobile functionalities. This work proposes a methodology and design architecture for implementing a portable $\text{IoT}$ system for $CO_{2}$ measurement and monitoring using the LI -830 sensor. The proposed $\text{IoT}$ system, which includes an online web platform for verifying real-time $CO_{2}$ measurements, has been designed for volcanologists to profile $CO_{2}$ emissions in a volcano. The core components of the $\text{IoT}$ Node are an ESP32 microcontroller and a SIM $800\mathrm{L}$ transceiver. An $\text{IoT}$ platform for data storage, processing and visualization was also developed using Python and Google Cloud tools. A pilot field test was conducted at the Cerro Pacho in El Salvador.