A Cloud-Based System for Visualizing Indoor Air Quality using AQI Guidelines

Imagine a family relaxing at home, unaware that invisible carbon monoxide is silently accumulating from a faulty heater. Indoor air pollution, often two to five times worse than outdoor air, claims 3.8 million lives annually due to respiratory and cardiovascular diseases. Yet, many lack the tools to detect these hidden threats. This study introduces the Indoor Air Quality System (IAQS), an Internet of Things (IoT)-based solution that empowers users to monitor and visualize air quality in real time. Combining Arduino microcontrollers, environmental sensors, and a user-friendly Progressive Web Application (PWA) built with JavaScript, HTML, and CSS, the IAQS adopts the U.S. Air Quality Index (AQI) and proposes a novel indoor scoring system to address the lack of global indoor standards. Rigorous testing, including 37-unit tests, 57 integration tests, and usability evaluations with five participants, achieved 100% accuracy in AQI, air quality score, and Humidex calculations, and 95% in truncated mean computations. Deployed in a polluted industrial area and a clean residential suburb, the IAQS maintained a data transfer error rate below 10%, demonstrating reliability. By translating complex data into actionable insights, the IAQS offers a scalable, affordable tool to safeguard indoor environments.