Air Pollution Monitoring System using Arduino and MQ135 Air Quality Sensor

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Hello friends! Welcome back to ElectroDuino. This blog is based on Air Pollution Monitoring System using Arduino and MQ135 Air Quality Sensor. Here we will discuss Introduction to Air Pollution Monitoring System, Project Concept, Block Diagram, Components Required, Circuit Diagram, Working Principle, and Arduino code.

Introduction

Day to day, the level of Air pollution is increasing rapidly due to increase industries, factories, vehicle use which affect human health. So here we have designed a device/system which can measure air quality around it and monitoring air pollution levels and also indicates and warns us when the air quality goes down beyond a certain level. This system can sense NH3, NOx, alcohol, Benzene, smoke, CO2, and some other gases, these gases are harmful to human health. It has a small display that will show the air quality value in the PPM unit. So this system is perfect for Air Quality Monitoring. This is a small portable device, we can use it at our home, office, classroom, and factory. It can save us from harmful gases.

Project Concept

The key components of the Air Pollution Monitoring System are MQ135, Arduino board, OLED Display, LEDs, and buzzer. The MQ135 is one type of gas sensor that can sense NH3, NOx, alcohol, Benzene, smoke, CO2, and some other gases, these gases are harmful to human health. Arduino is the main microcontroller board of this system. The gas sensor continuously measures air quality and sends data to the Arduino board. Then Arduino prints air quality value on the OLED display in the PPM unit. The LEDs and Buzzer used as indicators, it indicates the air quality is in good, Poor, or danger zone.

Block Diagram of Air Pollution Monitoring System using Arduino and MQ135 

Air Pollution Monitoring System using Arduino and MQ135 Block Diagram
Air Pollution Monitoring System using Arduino and MQ135 Block Diagram

Components Required 

Components NameQuantity
Arduino Nano1
MQ135 Gas Sensor1
0.96 inch I2C OLED display1
Green LED1
Red LED1
Buzzer1
220 ohm  Resistor2
Slide Switch1
9V Battery with Battery connector1
PCB Zero board1
Connecting wiresAs required in the circuit diagram

 

Tools Required

Tools NameQuantity
Soldering Iron1
Soldering wire1
Soldering flux1
Soldering stand1
Multimeter1
Desoldering pump1
Wirecutter1

Required Library

We need to add 3 libraries in Arduino IDE software. These are:

  • Download the MQ135.h library here: CLICK
  • Download the Adafruit_GFX.h library here: CLICK
  • Download the Adafruit_SSD1306.h library here: CLICK

Circuit Diagram of Air Pollution Monitoring System using Arduino and MQ135

Air Pollution Monitoring System using Arduino and MQ135 Circuit Diagram
Air Pollution Monitoring System using Arduino and MQ135 Circuit Diagram

Working Principle of Air Pollution Monitoring System using Arduino and MQ135 

When we turn on the system’s power supply, the MQ135 gas sensor starts sensing NH3, NOx, alcohol, Benzene, smoke, CO2, and some other harmful gases and it gives the output in form of voltage levels. This output voltage goes to the Arduino. Then the Arduino converts this voltage into PPM (parts per million) value with the help of the “MQ135.h” library which is defined in Arduino Code.  Then the PPM value will print on the OLED display.

When no harmful gases are present around the sensor, it will give us value of 90 PPM.  Normally the safe level of air quality is 350 PPM and it should not exceed the quality level of 1000 PPM.  When the air quality level exceeds 1000 PPM, then it starts to cause Headaches, sleepiness, and stagnant, stale. When this level exceeds 2000 ppm, it can cause increased heart rate and many other diseases.

For this reason, this system/device has indicators. When the air quality level is less than 1000 ppm, it indicates by turn on the green LED and the “Fresh Air” message is print on the Display. When this value will exceed 1000 PPM, it means the air is polluted, then the system indicates it by turn on the Red LED, and the “Poor Air” message is print on the Display. If this value will exceed 2000 PPM, it means the air is highly polluted, then the system indicates it by turn on the Red LED and Buzzer, and the “Danger! Air” message is print on the Display.

Arduino Code

 

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