Internet of Things (IoT)-Based Air Quality Monitoring Using An MQ-135 Sensor

Abstract

Air quality is an important factor affecting human health and comfort. Indoor air pollution can originate from various sources, such as cooking activities, smoke, and hazardous gases that cannot be directly detected by human senses. These conditions may have negative impacts on health if they are not monitored regularly. Therefore, a system capable of monitoring air quality quickly, easily, and in real time is required. This study aims to design and develop an air quality detection system using the MQ-135 sensor based on the Internet of Things (IoT), enabling air quality conditions to be monitored remotely through the internet. The research employed a quantitative method with an experimental approach, while the system was developed using the prototype method. The research stages included literature review, system design, hardware and software development, system testing, data collection, data analysis, and conclusion drawing. The developed system utilizes the MQ-135 sensor as a gas detector and the NodeMCU ESP8266 as the microcontroller, which is connected to the ThingSpeak platform to transmit, store, and display measurement data in real time. Testing was conducted in two indoor environments, namely a bedroom without air conditioning (AC) and a kitchen immediately after cooking activities. The test results showed that all system components functioned properly, the sensor was able to detect changes in air quality, and the measured data were successfully transmitted and visualized on the ThingSpeak platform via the internet. Based on the measurement results, the air quality in the kitchen after cooking showed higher sensor readings than that in the bedroom without air conditioning (AC), indicating poorer air quality. Therefore, the developed system is capable of monitoring indoor air quality in real time, providing information on air quality conditions, and serving as an Internet of Things (IoT)-based air quality monitoring system.