Obesity is a global epidemic and is increasing, with the World Health Organization reporting that the prevalence has almost doubled since 1980 in both children and adults.1 Environmental epidemiology has identified a number of environmental chemicals and mixtures, termed “environmental obesogens”, that may increase one’s risk for obesity.2, 3 In Southern California, near road-way air pollution (NRAP) remains one of the most relevant and pervasive environmental toxins, with minority and low-income communities disproportionately exposed to higher levels of NRAP.4, 5 Moreover, prenatal and early childhood exposure to NRAP have recently been linked to increases in body mass index trajectories and obesity outcomes at 18 years of age.6, 7 However, little is known about the brain-behavioral mechanisms by which prenatal and childhood NRAP exposure promote risk for obesity. The current research proposal aims to begin to elucidate if NRAP exposure may contribute to obesity through altering cognitive, emotional, and reward-based brain systems involved in food intake behaviors, such as over-eating and poor diet.8-11 Specifically, we will collect pilot data on brain structure and function, food-intake behaviors, and other lifestyle factors in 40 young adults from an ongoing CHS sub-study of air pollution and obesity (MetaAIR, PI: Gilliland). This preliminary dataset will be vital towards submitting a larger competitive NIEHS R01 grant to elucidate how the timing (prenatal, early postnatal, adolescence) and dose of NRAP exposure may impact brain-behavior circuitry and associated food-related behaviors to increase one’s risk of obesity. These questions are critical in order to better understand the environmental, neural, and behavioral mechanisms underlying the global obesity epidemic, as well as to better serve and treat diverse and underserved communities within the Southern California region that are most affected by NRAP-related health risks for obesity. By elucidating the brain-behavior mechanisms by which NRAP exposure contributes to obesity, we ultimately hope to help identify novel bio-behavioral targets for clinicians and reduce the public health burden associated with an otherwise lifelong battle with obesity.