Introduction

Air pollution is a major environmental concern in urban areas, leading to health issues and environmental damage. A Smart Pollution Control System uses IoT and sensors to monitor air quality in real time and takes automatic actions to reduce pollution, such as controlling industrial emissions or alerting authorities.

This system enables continuous monitoring, early detection, and smart intervention for pollution control.

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Objective of the Project

• To monitor air pollution levels in real time
• To identify harmful gases and particulate matter
• To alert authorities and public in case of high pollution
• To automate pollution control mechanisms

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Working Principle

1. Air quality sensors detect harmful gases like CO, CO₂, NO₂, and smoke
2. Particulate matter (PM2.5 / PM10) sensors measure dust and pollutants
3. Microcontroller processes sensor data
4. Data is uploaded to cloud via Wi-Fi for monitoring
5. Alerts are generated when pollution exceeds thresholds

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Components Required

• ESP32 / NodeMCU (ESP8266)
• MQ-135 Gas Sensor (Air Quality)
• MQ-7 Gas Sensor (CO detection)
• PM2.5 / Dust Sensor (e.g., SDS011)
• Buzzer / Alarm
• LED Indicators
• Wi-Fi module (ESP32 has built-in Wi-Fi)
• IoT Platform (ThingSpeak / Blynk / Firebase)
• Power Supply

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Block Diagram

Gas Sensors + PM Sensor
          ↓
      ESP32 / NodeMCU
          ↓
  Buzzer + LED Indicators
          ↓
         Wi-Fi
          ↓
    Cloud Platform

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Circuit Connections (ESP32 Example)

MQ-135 Gas Sensor

AO → GPIO34
VCC → 5V
GND → GND

MQ-7 Gas Sensor

AO → GPIO35
VCC → 5V
GND → GND

Dust Sensor (SDS011 or PMS5003)

TX → GPIO16
RX → GPIO17
VCC → 5V
GND → GND

Buzzer

+ → GPIO26
- → GND

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IoT Arduino Code (Smart Pollution Control System)

#include <WiFi.h>
#include "ThingSpeak.h"

#define mq135Pin 34
#define mq7Pin 35
#define buzzer 26

WiFiClient client;

const char* ssid = "Your_WiFi";
const char* password = "Your_Password";

unsigned long channelID = 123456;
const char* writeAPIKey = "YOUR_API_KEY";

void setup() {
  Serial.begin(9600);
  pinMode(buzzer, OUTPUT);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }

  ThingSpeak.begin(client);
}

void loop() {
  int airQuality = analogRead(mq135Pin);
  int coLevel = analogRead(mq7Pin);

  Serial.print("Air Quality: ");
  Serial.println(airQuality);
  Serial.print("CO Level: ");
  Serial.println(coLevel);

  if (airQuality > 400 || coLevel > 300) {
    digitalWrite(buzzer, HIGH);
  } else {
    digitalWrite(buzzer, LOW);
  }

  ThingSpeak.setField(1, airQuality);
  ThingSpeak.setField(2, coLevel);
  ThingSpeak.writeFields(channelID, writeAPIKey);

  delay(15000);
}

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Code Explanation

• Sensors detect gas concentration and particulate matter
• ESP32 monitors pollution levels
• Buzzer/LED alerts during high pollution
• Data is sent to IoT cloud for real-time monitoring

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Advantages

• Real-time air pollution monitoring
• Early detection of harmful gases
• Reduces health risks
• Supports smart city initiatives

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Applications

• Smart city pollution monitoring
• Industrial emission control
• Public health monitoring
• Environmental research

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Future Enhancements

• Mobile app notifications for residents
• Automated air purifiers activation
• AI-based pollution prediction
• Integration with city traffic and environmental systems

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Conclusion

The Smart Pollution Control System is a critical project for sustainable urban development. By combining IoT and sensors, it ensures continuous air quality monitoring and provides early warnings to reduce pollution and protect public health.