Abstract
Recently, air pollution has become a critical environmental concern globally as a result of rapid population growth, increasing vehicle emissions, industrialization, and urbanization. They are all factors that can negatively impact human health and the respiratory system. Consequently, this study presents a low-cost, Internet of Things (IoT)-based air quality monitoring system designed to provide real-time local and remote assessments of air pollution levels. The proposed system integrates an Arduino Uno microcontroller, an MQ135 gas sensor, and a NodeMCU ESP8266 Wi-Fi module for data collection, processing, and wireless transmission. The MQ135 sensor is used to monitor changes associated with different kinds of gaseous pollutants such as carbon dioxide, smoke, alcohol vapors, benzene, and ammonia. The MQ135 sensor data are processed by the Arduino Uno and displayed on an LCD screen as indicative air quality values. In addition, the air quality level is assessed according to predefined pollution thresholds. When the measured pollutant concentration exceeds a predefined safe limit, the system triggers an alert to indicate unsafe air pollution conditions. Besides that, the collected data is sent to the ThingSpeak cloud platform, where it is stored, analyzed, and displayed graphically as time-sequence graphs via a web interface. This allows users to remotely monitor air quality in real time using a computer or mobile device with an internet connection. Overall, the proposed system offers a simple, cost-effective, and accessible IoT-based solution for continuous air quality monitoring and early detection of potentially hazardous pollution.
