Evaluation of Particulate Matter (PM_2.5) Reduction through Greenwalls in Classrooms

Abstract

Background:The indoor air quality of classrooms, in which the capacity per unit area is high and students spend time together, must be managed for safety and comfort. It is necessary to develop an eco-friendly indoor air quality reduction method rather than biased management that relies solely on air purifiers.Objectives: In this study, plants and air purifiers were installed in middle school classrooms to evaluate the indoor PM 2.5 reduction.Methods: Four middle school classrooms were selected as test beds. Air quality was monitored in real-time every one minute using IoT equipment installed in the classrooms, corridors, and rooftops. After measuring the background concentration, plants and air purifiers were installed in the classroom and the PM 2.5 reduction effect was analyzed through continuous monitoring. Results: After installing the plants and air purifiers, the average PM 2.5 concentration was 33.7 μg/m 3 in the classrooms without plants and air purifiers, 25.6 μg/m 3 in classrooms with plants only, and 21.7 μg/m 3 in classrooms with air purifiers only. In the classroom where plants and air purifiers were installed together, it was 20.0 μg/m 3 . The reduction rates before and after installation were 4.5% for classrooms with plants only, 16.5% for classrooms with air purifiers only, and 27.6% for classrooms with both plants and air purifiers.The I/O ratio, which compares the concentration of PM 2.5 in classrooms with corridors and outside air, also showed the lowest in the order of plants and air purifiers, air purifiers, and plant-only classrooms. Conclusions:The PM 2.5 reduction effect of using plants was confirmed, and it is expected to be used as basic data for the development of environmentally-friendly indoor air quality improvement methods.