Evaluating the effectiveness of air purification in the real-world living and learning environment for pupils: A randomized, double-blind, crossover intervention trial

Abstract

Air purification has been proven to be an effective method for reducing personal fine particulate matte (PM2.5) exposure. A randomized, double-blind, crossover intervention trial involving 105 elementary school pupils in Mengzhou, China was conducted to investigate the effects of air purification interventions in living rooms and classrooms and evaluate the personal PM2.5 exposure determinants. Real-time PM2.5 samplers were used to monitor PM2.5 concentrations and questionnaires were used to collect basic information about pupils and their parents. The time-weighted method was applied to calculate personal PM2.5 concentrations and the mixed-effects model was used to examine the personal PM2.5 exposure determinants. The purification efficiencies of air devices were 32.5%–54.8% and 81.6%–92.4% in the living rooms and classrooms, respectively. Personal PM2.5 concentrations in the intervention group were lower than that in the control group. Air purification interventions, ambient PM2.5, indoor humidity, indoor temperature, temperature difference, and environmental tobacco smoke exposure were significant determinants of personal PM2.5 exposure. The living room and classroom interventions contributed to 42.31% [95% confidence interval (CI): 45.28%, 39.17%] and 21.34% (95% CI: 24.89%, 17.61%) reductions in personal PM2.5 exposure, respectively. These findings suggest that air purification interventions were effective in reducing personal PM2.5 exposure of pupils and living rooms intervention was the effective intervention method.