Design and Development of an Intelligent IoT-Based Air Quality Monitoring and Alert System, Challenges, Ethics, and Future Perspectives

Abstract

Air pollution poses a serious threat to human health and the environment, making continuous monitoring and timely warning systems essential for protecting public health. This article presents the design and development of an integrated Air Quality Monitoring and Alert System (AQMAS) that monitors particulate matter (PM2.5 and PM10), Carbon Dioxide (CO₂), Nitrogen Dioxide (NO₂), and Ozone (O₃) in real time using low-cost, easy-to-deploy sensor nodes. The system architecture comprises sensor nodes, an Arduino Uno microcontroller unit (with ESP32/Raspberry Pi noted as potential platforms for future wireless-communication upgrades), a cloud platform for data storage and visualization, and a multi-channel alert mechanism. Sensor readings are filtered using a moving-average technique, converted into standardized Air Quality Index (AQI) values based on EPA/WHO guidelines, and transmitted to a cloud dashboard for real-time monitoring. When pollutant concentrations exceed predefined safety thresholds, the system automatically dispatches alerts through SMS, mobile app notifications, and on-site LED/buzzer indicators, enabling both individuals and health authorities to respond promptly. Field testing showed PM2.5 concentrations ranging from 12 to 154 µg/m³ (mean 55 µg/m³), PM10 from 20 to 210 µg/m³, and CO₂ from 420 to 1100 ppm, with pollution peaks consistently observed during morning and evening traffic hours. The alert system successfully delivered real-time notifications within an average of 10 min of threshold breach. The results confirm that low-cost, IoT-enabled sensor networks can provide reliable, community-scale air quality monitoring and demonstrate strong potential for deployment in homes, schools, hospitals, and smart-city initiatives.