Particle removal effectiveness of portable air purifiers in aged-care centers and the impact on the health of older people

Abstract

Airborne particulate matter (PM) is associated with the risk of cardiovascular disease, and the elderly are more susceptible to the adverse effects of PM due to weakened immunity. In China, the use of portable air purifiers is a common method to reduce indoor PM pollution but few studies have evaluated the purification efficiency of portable air purifiers in the aged-care center under real living conditions. To evaluate the PM removal effectiveness of portable air purifiers in aged-care centers and the improvement of cardiovascular function of the elderly, a randomized double-blind crossover study was conducted in 16 rooms of an aged-care center in Yubei District, Chongqing, China in January 2020. The true purifiers and the sham purifiers (just remove filter gauzes) are used alternately in the elderly’s room, then the blood pressure and heart rate of elderly participants were tested. The study found that indoor PM concentration decreased rapidly within the first 2 h after turning on the air purifier, which can make indoor PM2.5 concentration lower than the WHO threshold. The air purifiers’ mean removal effectiveness of PM in the aged-care center is 73%, which is significantly affected by the window states. According to the multiple linear regression model, the factors predicting the PM concentration in aged-care centers are the usage of air purifiers, weather conditions and window states. Linear mixed-effect models were used to associate blood pressure and heart rate with air purification, which was found that indoor air purification was associated with a significant decrease in heart rate. This study indicates that portable air purifier is effective in improving aged-care center air quality, which is of great significance in improving the elderly cardiovascular health and providing guidance for the use of air purifiers in aged-care centers.