PROJECT SUMMARY/ABSTRACT Alaska Native and American Indian (ANAI) children experience a high burden of acute and chronic respiratory disease. Wood stove use, poor ventilation, and indoor tobacco smoke exposure have all been shown to cause poor indoor air quality (IAQ), which is associated with increased severity and frequency of respiratory infections in children. Portable HEPA purifiers have been shown to be effective in reducing particulate matter from tobacco and nontobacco smoke; however, despite demonstrated links between early-life severe respiratory infections, pediatric asthma, and adult pulmonary outcomes, no randomized trials to improve IAQ and associated health outcomes in children with bronchiolitis have been conducted. The IDeA States Pediatric Clinical Trials Network (ISPCTN) is developing a protocol for a clinical trial to address this gap. The proposal, “Reduction of indoor air pollution with high efficiency particulate air (HEPA) filtration to decrease respiratory symptom burden after hospitalization for bronchiolitis (IAQ bronchiolitis) is a placebo-controlled, multicenter clinical trial that aims to evaluate the efficacy of active HEPA filtration units, as compared with inactive HEPA filtration units, for reducing respiratory symptoms and increasing symptom-free days in children <12 months of age hospitalized with bronchiolitis. In 2019 the YK Health Corporation (YKHC) conducted a pilot project to provide education, HEPA filtration units and Healthy Homes Toolkits to households of children with chronic lung conditions such as bronchiectasis in the rural Yukon Kuskokwim Delta region of Alaska. In this diversity supplement, we will leverage and expand on a longstanding partnership between the Alaska ISPCTN investigators and YKHC to conduct an analysis of data from this 2019 pilot. We will assess the associations between household characteristics and HEPA filtration use, including duration of use. We will also compare household characteristics of homes with and without tobacco smokers. The proposed diversity supplement project will use existing data to support and expand the IAQ bronchiolitis trial and the ECHO focus area of upper and lower airway disease. Alaska Native/American Indian (AN/AI) people are under-represented in the medical profession and only 0.5% of We plan to mentor Madilyn Short, an Alaska Native (Yup’ik/Inupiat), first-year medical student from the rural Yukon Kuskokwim (YK) Delta region of Alaska, in a collaborative study between the Alaska ISPCTN and the Yukon Kuskokwim Health Corporation (YKHC). Madilyn is currently working as a research intern/assistant with Dr. Singleton and the Alaska Native Tribal Health Consortium’s Research Services and plans to complete her medical training and eventually practice medicine in Alaska with Alaska Native people.