Design of a Multi-Parameter Portable Air Quality Detection System for Subways

With the rapid expansion of urban rail transit networks and the exponential growth of passenger traffic, subway stations, as enclosed high-density passenger hubs, present severe challenges to indoor air quality. This paper designs an Internet of Things (IoT) environmental monitoring system. The system employs an STM32 microcontroller as its core, enabling real-time collection of critical parameters including CO2, formaldehyde (HCHO), PM2.5, and PM10 concentrations. Data is transmitted via a Wi-Fi module using the TCP protocol to PC-side software developed with Qt5. This software is capable of simultaneously receiving and visually displaying data streams from multiple monitoring nodes. Furthermore, it incorporates an early warning mechanism, facilitating the centralized monitoring and management of environmental conditions across diverse locations.