IoT based Air Pollution Monitoring System using Arduino

The IoT-based Air Pollution Monitoring System operates by combining sensing hardware with microcontrollers and wireless communication to track environmental conditions in real time. At the heart of the detection stage is the MQ135 gas sensor, which is sensitive to various harmful gases including carbon dioxide, smoke, and ammonia. As the concentration of these airborne pollutants changes, the analog resistance of the sensor changes, producing a corresponding analog voltage output. The Arduino Uno reads this analog signal using its built-in analog-to-digital converter. To make the data locally accessible, the Arduino processes the sensor values and drives a 16X2 LCD connected via digital pins, with a 10K potentiometer adjusting the display's contrast. Simultaneously, the system utilizes an ESP8266 Wi-Fi module (integrated via the SoftwareSerial library) to transmit the gathered air quality data to a remote web dashboard. The ESP8266 communicates with the Arduino Uno to bridge the local hardware circuit to a wireless network, using a 1K and 220 ohm resistor configuration for safe signal level management. Finally, if pollution levels cross a specific threshold defined in the software loaded via the Arduino IDE, a buzzer sounds locally to alert nearby individuals of poor air quality while the remote dashboard continues to log the live metrics.