Development of an IoT-Based Environmental Monitoring System for Indoor Air Quality in Schools in Kaduna State

Indoor air quality in Nigerian public school classrooms is rarely monitored, despite evidence linking poor ventilation and elevated pollutant levels to reduced cognitive performance and respiratory health risks among students. This project presents the development of an IoT-based environmental monitoring system for measuring and reporting indoor air quality parameters in school buildings in Kaduna State, North West Nigeria. The system monitors carbon dioxide concentration, particulate matter levels, temperature, and relative humidity using an MH-Z19B CO2 sensor, a GP2Y1010AU0F dust sensor, and a DHT22 temperature and humidity sensor. Sensor data is processed by an ESP8266 Wi-Fi microcontroller module and transmitted to the ThingSpeak IoT cloud platform for real-time visualization and historical data storage. Threshold-based alerts are generated on a web dashboard accessible to school administrators. The system was deployed in three classrooms of Government Secondary School Rigasa in Kaduna over a four-week monitoring period. Data revealed that CO2 levels exceeded the 1,000 ppm guideline threshold in all three classrooms during peak occupancy hours, while particulate matter levels were elevated on days of high outdoor wind activity. The findings provide empirical evidence for improved ventilation standards in Nigerian school infrastructure. The system hardware was assembled for approximately 12,500 Naira per unit, making widespread deployment economically feasible. Keywords: IoT monitoring, indoor air quality, school environment, Kaduna State, environmental sensors