Project Summary Abstract There is a fundamental gap in understanding how indoor exposures to environmental contaminants affect the health of older adults living or spending time in senior care facilities. Continued existence of this gap represents an important problem, because until it is filled, development of interventions and regulations to reduce health risks associated with indoor exposures in senior care facilities will remain unattainable. The long-term goal of our research program is to examine risks associated with exposure to persistent organic pollutants (POPs) in senior care facilities for future development and implementation of interventions to prevent or reduce these risks. Our objective in this application is to determine the connection between ambient conditions, personal exposures, and biomarkers of exposure to POPs among the residents of senior care facilities located in Indiana. We hypoth- esize that there is a significant association between ambient conditions, personal exposures, and biomarkers of exposure in senior care facilities. Our rationale for the proposed study is that the knowledge obtained through this research will advance our understanding of the impacts of indoor exposure to POPs on health of the resi- dents of senior care facilities. We will use innovative non-invasive data collection techniques to pursue the fol- lowing specific aims: 1) Determine ambient levels of five POP groups (polychlorinated biphenyls, organochlorine pesticides, polycyclic aromatic hydrocarbons, brominated flame retardants, and organophosphate esters) in sen- ior care facilities in Indiana via air and dust sampling; 2) Estimate personal exposures to target chemicals among residents of the facilities using silicone wristbands as personal passive samplers; 3) Determine biomarkers of exposure to POPs through analysis of nails, a non-invasive biomonitoring technique. The study will recruit 100 residents of senior care facilities located in Indiana (10 facilities with 10 participants per facility) for the exposure assessments. We will examine indoor exposures through air and dust sampling in participants' rooms. We will use silicone wristbands as innovative passive samplers of personal exposures and we will measure biomarkers of POPs in nail clippings collected from participants. This approach is innovative because it examines a previ- ously unrecognized exposure to POPs in an understudied settings with particularly vulnerable population, and because it employs silicone wristbands and nails as novel, simple, and non-invasive ways to measure personal exposures and biomarkers of exposure. The proposed research is significant because accomplishing these spe- cific aims will advance our understanding of how exposure to POPs may impact health of a vulnerable population of older adults. This information will provide an essential foundation for subsequent applications to investigate and reduce risks associated with this exposure through epidemiological studies and targeted interventions.