Air pollution has emerged as one of the most critical environmental and public health challenges globally, driven by rapid industrialization, urbanization, and increased vehicular emissions. Conventional air quality monitoring systems are expensive, stationary, and provide limited spatial coverage. This paper presents a drone-based air quality monitoring system that integrates multiple environmental sensors with Internet of Things (IoT) technology on an Unmanned Aerial Vehicle (UAV). The system employs an MQ-135 gas sensor, FC-22 gas sensor, ozone (O3) sensor, particulate matter sensors (PM2.5 and PM10), nitrogen dioxide (NO2) sensor, and a DHT11 temperature-humidity sensor to measure key pollutants in real time. Data is processed by an Arduino Nano microcontroller and transmitted wirelessly to cloud platforms for analysis and Air Quality Index (AQI) computation. The UAV enables flexible monitoring at different altitudes and locations, including hazardous or inaccessible areas. Field experiments conducted over a 1 km × 1 km urban traffic corridor at altitudes of 10 m and 50 m demonstrate clear spatial and temporal variation in PM10, PM2.5, O3, NO2, and CO concentrations. The proposed system is lightweight, portable, low-cost, and capable of generating real-time AQI data, establishing a strong foundation for future smart-city pollution management integrated with artificial intelligence and advanced cloud analytics.

Keywords— UAV; Air Pollution Monitoring; IoT; Arduino Nano; AQI; MQ-135; PM2.5; PM10; O3; NO2; Environmental Monitoring; Drone Technology