The Effects of Indoor Air Filtration on Peak Expiratory Flow (PEF) in Children with Stable Asthma: A Randomized Double-Blind Crossover Trial in Shanghai, China

Air pollution is a global environmental and public health issue. With an estimated 92% of the world’s population living in areas exceeding the World Health Organization’s air pollution standards many individuals and households turn to environmental control measures like indoor air filtration devices to reduce exposure to air pollutants and protect health. The health effects of air pollution are universal, but there are susceptible populations which are more sensitive, such as asthmatic children. This study examines the effect of an indoor air filtration intervention on the peak expiratory flow (PEF) of asthmatic children, by conducting a crossover trial in Shanghai, China. Compared to sham filtration, true filtration significantly decreased the levels of PM2.5 by 60%, and increased peak expiratory flow (PEF) by 4.2 l/min [95% CI: 2.4, 6.0], indicating improvements on lung obstruction. This indicates that the use of indoor air filtration may provide health benefits in asthmatic children living in areas with moderate levels of ambient air pollution.