The potential of mobile air cleaners for particle removal in school classrooms: A field study

In this field study, we assess the potential of using mobile air cleaners (MACs) to reduce the concentration of respiratory particles, responsible for the cross-infection of respiratory diseases, in school classrooms. We used three types of MAC which were found to yield comparably good performances in lab-controlled particle decay tests aimed at measuring their clean air delivery rates (CADR). The purpose of this field study is to evaluate the efficiency of these carefully pre-selected MACs in actual classrooms during typical teaching activities, hence determining whether such high-CADR devices are actually suitable in such real-life situations. The particle and CO 2 concentrations were measured continuously over 6 weeks in 15 classrooms of five primary schools in the Netherlands, three classrooms per school, each equipped with one of the three types of MACs which were turned ON either during the first or the last 3 weeks of the study and turned OFF otherwise. We found that the use of these MACs, with optimum number of devices, location and fan level settings, leads to a systematic reduction in the overall particle concentrations, typically by a factor 2.