Classroom Indoor Air Quality Dataset Collected Using ESP32 and SCD41 Sensors

Environmental data were collected using a Freenove ESP32-WROOM microcontroller integrated with a Sensirion SCD41 sensor. The system measured CO₂ concentration (ppm), temperature (°C), and relative humidity (%) at regular intervals. Data were transmitted wirelessly via Wi-Fi using an HTTP interface and stored in an InfluxDB time-series database. Contextual information, including the number of students present, maximum classroom capacity, window and door status, and class type (lecture or discussion), was recorded during each session.