PROJECT SUMMARY Air pollution can impact cognitive disorders such as attention deficit hyperactivity and behavioral problems. Children are particularly vulnerable to environmental exposures because of the sensitive nature of child development, a life stage marked by rapid cell differentiation. A growing body of literature on air pollution shows increasingly diverse effects on childhood health, development and disease. This research study will further add to the literature by both addressing the main effect of air pollution on sleep and the modifying effect of co- exposure to social stressors. Specifically, we will examine potential relationships between ambient air quality and its effects on sleep patterns among children, 6-7 years old. Specific Aim are to: 1) Determine the association of prenatal PM2.5 exposure and child sleep quantity and awakening at night assessed at 6-7 years using a satellite remote sensing PM2.5 model and wrist-worn continuous actigraphy over 7 days; 2) Determine if early life stress indexed by negative life events, maternal trauma, and exposure to violence predicts sleep quantity and awakening at night and modifies the impact of prenatal PM2.5 on sleep assessed at age 6-7 years. By identifying risk factors for poorer sleep phenotypes, we can begin to address interventions targeting toxic impacts on child health. Furthermore, I posit that ambient air quality and sleep may work independently or synergistically through a shared inflammatory pathway, and thus a better understanding of this relationship could mitigate modifiable risk factors that improve childhood health outcomes. It is further postulated that this proposed research will contribute to the sparse literature on air quality and sleep health among children by examining pediatric environmental health, ambient air quality and potential stress induced modifying effects on sleep patterns in children. Using the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) longitudinal birth cohort study to conduct the proposed research, this study will expand the literature on sleep and sleep disparities, a research void that if addressed has the potential to mitigate the adverse impact of child sleep disparities on long term health.