IOT Based: Air Quality Monitoring System

Abstract

Airpollutionhasemergedasacriticalglobalconcern,posing seriousthreatsto humanhealth, climate stability and ecological balance. Conventional air quality monitoring stations are often expensive, stationary, andlimitedincoverage, restricting theirabilitytoprovidereal-timelocalizeddata.Toaddressthis challenge, this study presents the design and development of an Internet of Things (IoT)-based Air Quality Monitoring System utilizing low-cost sensors and wireless communication. The proposed system employs the MQ135 sensor to detect harmful gases, such as carbon dioxide, ammonia, and nitrogen oxides, whereas the DHT11 sensor is used to monitor ambient temperature and humidity levels. The collected data were processed usingan ESP8266microcontroller,whichenabledreal-timewirelesstransmissionandvisualizationonanLCD display through an I2C interface. The modular design ensures portability, scalability, and energy efficiency, making it suitable for smart-city applications. The experimental results demonstrate the feasibility of the proposedsystemindeliveringaccurate andtimely airquality dataatasignificantly reducedcostcomparedwith traditional monitoring infrastructure. This study contributes to the advancement of low-cost environmentalmonitoringsolutions,enablingimprovedpublicawarenessanddata-drivendecision-makingforpollution control.

Introduction

???? 1. Background & Motivation

• Air pollution is a growing global concern due to urbanization, industrialization, and vehicle emissions.

• Over 90% of the global population is exposed to unsafe air quality (WHO).

• Traditional air monitoring systems are accurate but costly, large, and offer limited coverage.

• There is a need for low-cost, real-time, and localized monitoring solutions.

???? 2. Role of IoT in Air Quality Monitoring

• IoT technology enables real-time, distributed, and affordable monitoring using:

  • Sensors (MQ135 for gases, DHT11 for temp/humidity)

  • Microcontrollers (ESP8266)

  • Cloud and Wi-Fi connectivity

• Data can be visualized locally (via LCD display) or remotely (via web/mobile dashboards).

• Such systems support smart cities, public health, and environmental awareness.

?? 3. Proposed System Overview

The proposed system is a cost-effective, portable, and scalable air quality monitoring solution with:

???? Components:

• MQ135 sensor: Detects pollutants (CO?, NH?, NOx, benzene, VOCs).

• DHT11 sensor: Measures temperature and humidity.

• ESP8266 microcontroller: Processes data and enables Wi-Fi communication.

• 16x2 LCD with I2C: Displays readings on-site.

???? Connectivity:

• Wireless data transmission via Wi-Fi for remote access and cloud integration.

???? 4. Key Features

???? 5. Methodology

The system development follows four main stages:

1. Data Acquisition

• MQ135 captures air pollutants.

• DHT11 measures environmental conditions.

• Sensors send data to ESP8266.

2. Data Processing

• ESP8266 processes and calibrates raw data.

• Air Quality Index (AQI) levels are computed (e.g., Good, Moderate, Poor).

3. Data Transmission

• Wi-Fi-enabled ESP8266 sends data to cloud platforms for remote access and storage.

4. Data Visualization

• Local: Displayed on 16x2 LCD (I2C for simplified wiring).

• Remote: Visualized on dashboards or mobile apps (optional).

???? 6. Literature Insights

• Previous studies implemented similar systems but had limitations:

  • Lacked wireless communication or environmental data (temp/humidity).

  • GSM-based systems had high operational costs.

  • More complex systems had high hardware requirements.

• This study improves upon them by balancing cost, functionality, and expandability.

???? 7. Contribution

• Provides a practical, IoT-driven air monitoring system that is:

  • Affordable

  • Energy-efficient

  • Easy to deploy

• Supports smart city initiatives and public environmental awareness.

Conclusion

This paper presented an IoT-basedAir Quality Monitoring System using the ESP8266, MQ135, and DHT11 sensors with an LCD interface. The system effectively monitors airpollutants,temperature,andhumidityinrealtimewhileproviding bothlocalandwireless dataaccess. Its lowcost,portability, and scalability make it a practical alternative to traditional monitoring stations. TheprojecthighlightsthepotentialofIoTinenvironmentalmonitoringandsmartcityapplications. Futureenhancements mayincludeaddingparticulatematter sensors, mobiledashboards, and renewable energy integration to improve reliability and coverage.

References

[1] I. G.A. I.F.Ramadhani,T. Z.Putri,Y. D.Asmarita,S.Amania, N.Mufti,M.A.Mizar,H.Ismail, andH.Arrosyid, “IoTImplementationforAir QualityMonitoringSystemusingLowCostSensor,”in Proc. IEEE Int. Conf. on Industry 4.0, Artificial Intelligence, and Communications Technology (IAICT), 2025, pp. [2] R. Garg,A. Kumar, R. Dayana, and S. Singh, “AdvancedAir Quality Monitoring System using IoTandSensorTechnology,”inProc.3rdInt.Conf.onIntelligentDataCommunicationTechnologies and Internet of Things (IDCIoT), 2025, pp. [3] A. Fatima, F. Faiz, M. F. Khan, S. Shabir, and S. Anjum, \"Air Sense: Internet of Things-enabled Novel Power Efficient Indoor Air Quality Monitoring System,\"IEEE Access, vol. 12, pp. [4] K. Narayanasamy, S. B. Saon, M. B. Othman, and A. K. Mahamad, \"IoT-Based Air Quality Monitoring System with Air Filter,\"2024 International Conference on Future Technologies for Smart Society (ICFTSS), pp. [5] M. Imam, S. Adam, S. Dev, and N. Nesa, \"Air quality monitoring using statistical learning models for sustainable environment,\"Intelligent Systems with Applications, vol. 22, p. 200333, 2024.

Copyright

Copyright © 2025 Ms. Ritika Desavale, Mr. Om Rakibe, Ms. Sejal Kad Deshmukh, Mr. Prathamesh Palkar, Prof. N. S. Thombare. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.