Abstract
Air pollution poses a significant threat to human health, making continuous indoor air quality monitoring crucial in modern smart residences. This work proposes an IoT-enabled AQI Surveillance System using an ESP32 microcontroller as the central controller. The system integrates an MQ135 gas sensor for detecting harmful gases (CO, CO₂, NH₃), a DHT11 sensor for temperature and humidity monitoring, and a NEO-6M GPS module for geo-tagged alerts. The collected data is processed and displayed in real-time on an LCD screen. A relay-driven exhaust fan mechanism is incorporated to automatically improve air circulation and reduce pollutant concentration whenever poor air quality is detected. Additionally, buzzer and LED indicators provide instant audio-visual warnings during hazardous conditions, while a battery backup maintains operation during power outages.
To ensure reliability and accessibility, the system leverages ThinkSpeak for cloud data storage and analytics, Blynk for remote visualization and smartphone notifications, and a dedicated web dashboard for real-time online monitoring and user interaction. This integrated smart monitoring approach ensures healthier living environments by combining sensing, automation through relay-controlled exhaust fans, IoT connectivity, and web-based accessibility.
Introduction
Air pollution has emerged as one of the most critical global health challenges of the 21st century, with the World Health Organization (WHO) identifying it as a major contributor to respiratory illnesses, cardiovascular diseases, and reduced life expectancy. While outdoor air pollution receives significant attention, indoor air quality (IAQ) is often overlooked despite the fact that people spend nearly 80–90% of their time indoors. Pollutants such as carbon monoxide (CO), carbon dioxide (CO₂), ammonia (NH₃), and volatile organic compounds (VOCs), combined with inadequate ventilation, pose a severe threat to the health and comfort of residents in modern homes. Therefore, continuous indoor air quality monitoring and automated mitigation strategies are essential to ensure healthier living environments.
With the advent of the Internet of Things (IoT), real-time monitoring and control systems have become feasible, enabling smart homes to evolve beyond basic automation into intelligent, health-centric living spaces. IoT-based AQI surveillance systems not only sense environmental parameters but also communicate the data to cloud platforms for analysis, storage, and visualization. This facilitates predictive insights, remote monitoring, and proactive decision-making for air quality management.
This work proposes an IoT-enabled AQI Surveillance System using the ESP32 microcontroller as the central processing unit. The system integrates multiple sensors, including an MQ135 for harmful gas detection and a DHT11 for temperature and humidity monitoring. A NEO-6M GPS module provides geo-tagging capabilities for location-based air quality alerts. The collected data is displayed locally on an LCD screen for instant visualization. To ensure active response, the system employs a relay-driven exhaust fan that automatically activates when pollutant levels exceed safe thresholds, thereby improving ventilation. Additionally, buzzer and LED indicators provide immediate alerts during hazardous conditions.
Beyond local monitoring, the system ensures broader accessibility and reliability by leveraging IoT platforms. ThinkSpeak is utilized for cloud-based data storage and analytics, while the Blynk application provides smartphone-based remote visualization and notifications. A dedicated web dashboard further enhances real-time online monitoring and user interaction. To maintain uninterrupted operation, the system incorporates a battery backup mechanism that allows continuous functioning during power outages.
By integrating sensing, automation, IoT connectivity, and user-friendly interfaces, the proposed AQI Surveillance System addresses the pressing need for maintaining healthy indoor air in smart residences. This approach not only ensures immediate mitigation of pollution but also empowers residents with actionable insights for long-term well-being.