Analysis of Factors Influencing Indoor PM2.5 and CO2 Concentrations in Households using IoT Technology after Indoor Garden Installation

Background and objective: Plants are a natural and environmentally friendly way to improve indoor air quality. To evaluate indoor air quality, it is important to continuously measure and identify the influencing factors. This study aimed to identify the factors affecting PM2.5 concentration in indoor spaces with indoor garden installations. Methods: Factors influencing the concentration of indoor, airborne PM2.5 were monitored based on Internet of Things (IoT) technology. Ten households in South Korea were surveyed and categorized into Groups A (households without an indoor garden) and B (households with an indoor garden). An IoT-based device was used to monitor the indoor PM2.5 concentration and several environmental factors, including the outdoor PM2.5 (μg·m-3) and carbon dioxide (mL·m-3) concentrations, temperature (°C), and relative humidity (%). Further, the seasonal (spring, summer, fall, and winter) and temporal (dawn, morning, afternoon, and evening) variations in indoor PM2.5 concentration were monitored. Results: The indoor PM2.5 concentration decreased from 17.7 μg·m-3 to 16.7 μg·m-3, and from 15.5 μg·m-3 to 12.5 μg·m-3 in Groups A and B, respectively. A regression analysis showed that the indoor PM2.5 concentration was not significantly affected by the installation of the indoor garden (living rooms: p = .1577; kitchen: p = .4974); however, was influenced by the outdoor air conditions, as well as seasonal and temporal factors. Additionally, a subgrouping model demonstrated a statistical relationship between indoor garden installation and the environmental factors. Conclusion: These findings can assist in establishing guidelines for indoor air quality management.