“Successful Aging in a Time of Wildfires” is a research study designed to examine the effects of chronic and acute wildfire smoke exposure on the successful aging of community-dwelling older adults living in California. Over 1.4 million wildfires have occurred in the U.S. since 2000, burning an average of 7 million acres annually. Emissions from wildfires pose significant threats to human health, including cardiovascular, respiratory, and neuro-cognitive effects, and are estimated to cause more than 15,000 fatalities per year. Older adults are particularly vulnerable to the impact of wildfire emissions, which exacerbate respiratory and cardiac diseases. However, beyond direct physical health effects it remains unclear how sociodemographic factors shape older adult exposure to wildfire smoke and how this exposure subsequently impacts the functional, cognitive, and socio-behavioral aspects of successful aging. As California is at particularly heightened risk of wildfires, this study will recruit a racially and ethnically diverse longitudinal cohort of 1,000 community-dwelling older adults from California and apply a hierarchical socio-ecological model to the question of whether exposure to wildfire emissions affects the successful aging of older adults. The strategy reflects a multidisciplinary approach in which the researchers measure and model ambient toxins in both outdoor and indoor air; collect and assess epigenetic changes in older adults’ exosomes; and evaluate the social, psychological, and behavioral factors that moderate the environmental and biological exposure factors and their impact on successful aging. The broad long-term objectives of the study are to identify those factors amenable to prevention, mitigation, or adaptation, so that older adults living in wildfire-susceptible regions of the country can safeguard their health by attending to the air around them, the buildings in which they live, and to the social supports and protective behaviors in which they can engage. The research study has four specific research aims: (1) to develop a California-based observational cohort of older adults with various levels of wildfire exposure from 2002-present; (2) to estimate outdoor and indoor exposure to chemically- explicit wildfire emissions among cohort participants; (3) to analyze saliva samples to identify epigenetic markers of wildfire-exposure, and analyze their association with inflammatory processes and functional impacts on neurological, cardiovascular, and respiratory systems; and (4) to develop and test an ecological model for successful aging in older adults exposed to wildfire emissions that integrates exposure and behavioral data to determine the relationship between wildfire smoke exposure and successful aging outcomes.