Cleaning indoor air-what works for respiratory health: An updated literature review and recommendations.

Indoor air pollution is a growing public health concern globally and is associated with increased respiratory symptoms and morbidity. Individuals spend most of their time indoors, and pollutant-related health effects are often driven by the indoor environment. Understanding effective interventions to improve indoor air quality and their impact on respiratory outcomes is key to decreasing the burden of air pollution for high-risk populations across the life-span. This review applies a hierarchy of interventions framework specific to respiratory health effects and focuses on recent studies of interventions to improve indoor air quality among high-risk populations with chronic respiratory disease published in the past 3 years. While policy and source control interventions are likely the most effective and equitable approaches to improve indoor air quality and benefit population health, these were less extensively investigated. Engineering interventions, such as air cleaner interventions, were the most widely studied. Several studies, including those focused on asthma and chronic obstructive pulmonary disease, demonstrated improvement in symptoms and medication receipt with interventions in both home- and school-based settings. Combined multilevel interventions with engineering and behavioral interventions led to improved respiratory outcomes in some, but not all, studies. Placing the recent work in the context of the broader literature, we identify gaps in research. Further research is needed to understand intervention effectiveness over time and an increased focus on policy and source control interventions that can mitigate risk in vulnerable populations.