IoT Based Air Pollution Monitoring System

Air Pollution Detector

Air is the most precious thing on Earth required for the existence of life on earth. But nowadays our air is getting polluted day by day due to industrialization and other human activities. Air pollution refers to the release of pollutants into the air known as pollutants that are detrimental to human health and the planet as a whole. According to the World Health Organization (WHO), each year air pollution is responsible for nearly seven million deaths around the globe. Introduction of new technologies reduces exposure to air contamination, in which new measures have been pursued, including the development of air quality measuring devices and air purifiers.

This project is based on an  IoT Based Air Pollution Monitoring System in which we will monitor Air Quality over a web server using the internet. And will trigger an alarm when the air quality goes down beyond a certain level, which indicates that there are sufficient amounts of harmful gases present in the air like CO2, smoke, alcohol, benzene, and NH3. It will show the air quality in PPM on the LCD and as well as on the webpage so that we can monitor it very easily. Moreover,  a  temperature and humidity sensor is included as these conditions can impact the performance of the gas sensors. It is quite important to create devices like this because excessive pollution such as CO2  emissions causes harm to the  Earth.  This device helps collect data about the air quality, so air quality issues can be resolved.

What is  Air Pollution Monitoring System?

The Air Pollution Monitoring System is a device used to measure the concentration of air pollutants (such as SO2, NOx, CO, O3, THC, etc), and particulate matters continuously all year round. The measured data is monitored and transmitted to various formats to the local central authorities. The data is further published via the Internet for easy public access to raise awareness on current air pollution levels. This way, the public can prevent outdoor activities and reduce health impacts during heavily polluted days.

Air quality of the system is calculated using the Air Quality Index, or AQI. The AQI operates as a thermometer that runs from 0 to 500 degrees. However, instead of showing changes in the temperature, the AQI is a way of showing changes in the amount of pollution in the air. Air quality defines how much clean or polluted the air is.

The air in our atmosphere is mostly made up of two gases that are essential for life on Earth: nitrogen and oxygen. However, the air also contains smaller amounts of many other gases and particles. AQI tracks five major air pollutants:

  • Ground level ozone
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen dioxide
  • Airborne particles, or aerosols

Ground level ozone and airborne particles are the two air pollutants that pose the greatest risk to human health in the United States. They are also the two of the main ingredients in smog, a type of air pollution that reduces visibility.

Need for Air Pollution Monitoring System:

  • Function as the Smart-Air for the precise monitoring of indoor air quality
  • We propose the utilization of an IoT for efficient monitoring of real-time data
  • Operates as the adoption of cloud computing for real-time analysis of indoor air quality
  • Can be developed into a mobile application to make the proposed IoT system with features of anytime, anywhere
  • The device has been tested for reliability of the data and the platform has been implemented in a building to test its feasibility


  • MQ135 Gas sensor
  • Arduino Uno
  • Wi-Fi module ESP8266
  • 16X2 LCD
  • Breadboard
  • 10K potentiometer
  • 1K ohm resistors
  • 220 ohm resistor
  • Buzzer

This  Proposed Air Pollution Monitoring System is based on the block diagram given above. The air in the atmosphere is recognized by the MQ135 gas sensor and MQ6 LPG gas sensor. The MQ135 sensor can sense NH3, NOx, alcohol, Benzene, smoke, CO2. So it is a dynamic gas sensored for our Air pollution Monitoring system. When it is connected to Arduino then it will sense all gases, and it will give the Pollution level in PPM(parts per million). 

The MQ135 gas sensor output the data in the form of voltage levels and we have to convert it into PPM.   The sensor provides a value of 90 when there is no gas near it and the air quality safe level is 350 PPM and it should not exceed 1000 ppm.

  • Arduino Uno:

 Arduino Uno is an open-source based on the Microchip ATmega328P developed by Arduino. cc. The current version of Arduino Uno comes with a USB interface, 14 digital I/O pins, 6 analog pins, an ICSP header, 16 MHz ceramic resonators, a power jack,  and a reset button. And an Atmega328 microcontroller is used to connect with external electronics circuits.

  • MQ135 sensor:-

 The MQ135 sensor can sense NH3, NOx, alcohol, Benzene, smoke, CO2, and some other gases.  It offers very good sensitivity and a fast response time makes it ideal such as used in air quality control types of equipment. 

  •  WIFI Module (ESP8266):-

  ESP8266 Wifi Module AP & Station Remote Serial Wireless IoT Board designed based on an integrated chip specifically to fulfill the needs of a new connected world. It can handle all the necessary overhead for communicating with your network, such as TCP/IP stack and  communicating with your 802.11 networks 

  • Buzzer:

  A Buzzer or beeper is an audio signaling device. Whenever the air pollution goes above the threshold level the Buzzer starts beeping indicating Danger.

  •  LCD (Liquid Crystal Display):

   This is a basic (16×2) 16 character by 2 line display. Black text on Green background. It is used to indicate Air and Humidity in PPM.

  • GSM Module:

   GSM Module is used to establish communication between a computer and a GSM system. Global System for Mobile communication (GSM) is an architecture used for mobile communication.

  • LPG Sensor:

    MQ-6 sensor is a simple-to-use liquefied petroleum gas (LPG) sensor, suitable for sensing LPG (composed of mostly propane and butane) concentrations in the air.  The MQ-6 can detect gas concentrations anywhere from 200 to 10000ppm. 

  • Temperature Sensor:

   The LM35 is a precision integrated-circuit temperature sensor, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.  It can be used with single power supplies, or with plus and minus supplies. 

  • Humidity Sensor:

  The humidity sensor is of a capacitive type, comprising an chip signal conditioner.  

. Applications:

  •  Industrial perimeter monitoring 
  • Indoor air quality monitoring. 
  •  Site selection for reference monitoring stations.
  •  Making data available to users. 


  •  Easy to Install
  • Updates On mobile phone directly  
  •  Accurate Pollution monitoring  
  •  Remote location monitoring  

Conclusion:     The proposed system is used to monitor the air of the environment using an Arduino microcontroller, sensors, buzzer, and LCD Display.  IoT Technology is adopted to improve the quality of air. The use of IoT technology enhances the process of monitoring various aspects of the environment such as air quality monitoring issues. Here, using the MQ135 and MQ6 gas sensors gives the sense of different types of dangerous gas and Arduino is the heart of this project. Which controls the entire process. The Wi-Fi module connects the whole process to the internet and LCD is used for the visual Output. Real-time monitoring and a rapid alert system produce an efficient platform for improving indoor air quality.

Leave a Reply

Your email address will not be published.