Aim 1: To assess the effect of a 6-month residential HEPA intervention on changes of type 2 diabetes-related metabolic outcomes in 52 adults. We hypothesize that compared to sham filtration, HEPA filtration will lead to an improved cardio-metabolic profile including reduced fasting glucose, HbA1C, HOMA-IR, LDL and blood pressure as well as increased HDL. The findings will provide the first evidence on intervention benefits with respect to diabetes-related quantitative traits.

Aim 2: To examine the association between reduction in indoor PM_2.5 exposure brought by the intervention and changes in metabolic outcomes adjusting for ambient PM_2.5 exposure. We hypothesize that a greater reduction in indoor PM_2.5 exposure will result in a greater improvement in the cardio-metabolic profile. If the hypothesis is proven true, the finding will support practices to maximize indoor PM_2.5 reduction through expanding the proper use of filtration devices in other indoor environments.

Aim 3: To explore major pathophysiologic changes pertinent to the cardio-metabolic profile of type 2 diabetes relevance in response to the intervention and changes in PM_2.5 exposure. The findings from this aim will help identify novel biomarkers to predict the disease risk and improve the understanding of biological mechanisms. The insights can help develop other personal-level preventive strategies such as therapeutic interventions.

Impact: We plan to use a low-cost HEPA filtration device in this double-blind cross-over trial. If the intervention is proven to be beneficial, residential use of air purifiers will be recommended as a practical means to reduce air pollution-induced risk for diabetes, which has no foreseeable side effects.