The effect of particulate matter reduction by indoor air filter use on respiratory symptoms and lung function: A systemic review and meta-analysis

Abstract BackgroundExposure to particulate matter (PM) is a key public health issue, but effective intervention has not yet been established. A systematic literature review and meta-analysis has been conducted to assess the relationship between the use of air filters, one of the most-studied interventions, and respiratory outcomes in patients with chronic respiratory disease.MethodsWe systemically reviewed intervention studies on PM using Pubmed, EMBASE, and Cochrane databases up to September 2019. Studies that included data on PM level changes and respiratory symptoms or lung function in patients with respiratory diseases were eligible for inclusion. Effect estimates were quantified separately using the random-effects model.ResultsSeven studies were included in our study. Air filter use reduced indoor PM2.5 by 11.45 µg/m3 (95% confidence interval [CI]: 6.88–16.01 µg/m3). Air filter use improved predicted forced expiratory volume in one second (FEV1) by 3.60% (95% CI: 0.29–6.90%). Air filter use was not associated with a significant change in respiratory symptoms (odds ratio: 0.82; 95% CI: 0.62–1.08).ConclusionThe findings from this systematic review suggest that a role for air filter with respect to reduced indoor PM and increased lung function. Further studies in high density PM regions may provide additional information on this role.Systematic review registration: PROSPERO: on review ID 156258