IoT System for Indoor Air Quality Monitoring in Accordance with European and International Standards

Abstract

The Internet of Things (IoT) has facilitated the creation of affordable and dependable solutions for real-time environmental monitoring. This paper discusses the design and evaluation of a smart indoor air quality monitoring system that combines an M701 multifunctional air quality sensor with an ESP32 microcontroller. The system measures carbon dioxide, particulate matter (PM₂.₅ and PM₁₀), formaldehyde, total volatile organic compounds, temperature, and relative humidity. Data from the sensor module are securely transmitted to the server using the Message Queuing Telemetry Transport (MQTT) protocol over Transport Layer Security (TLS), ensuring data integrity and confidentiality. Measurements were taken in a 30 m² office space under stable operating conditions. The results showed that most values remained within the limits recommended by international and European guidelines, although occasional exceedances were noted for formaldehyde and total volatile organic compounds. The system exhibited high reliability, stability, and scalability, making it suitable for integration into heating, ventilation, and air conditioning systems, as well as for implementing predictive analytics for proactive air quality management.