This is an application for the Academic Research Enhancement Award (AREA) for Undergraduate-Focused Institutions to carry out a toxicological study to gain insights about the biological basis by which particle pollution can alter brain function during adolescence and its potential impact in mental health disorders. Ambient particulate matter (PM) is the leading environmental health risk factor and largest driver of air pollution’s burden of disease worldwide. Epidemiological studies have found associations between exposure to particle pollution and adverse neurocognitive outcomes. However, there is a gap in knowledge about the windows of vulnerability and mechanisms by which PM negatively impact the central nervous system (CNS) and its clinical implications. To this extent, the overall goal of this application is to evaluate the neurocognitive effects of particle pollution throughout adolescence. During this life stage, key processes in postnatal brain development of regions such as the prefrontal cortex might render adolescents susceptible to environmental insults. About 50% of mental health disorders have an onset during adolescence, many of which persist throughout the lifespan with long-lasting impact in the well- being of individuals and their families. Our preliminary studies suggest that the prefrontal cortex is a target for particle pollution. Structural and functional alterations in the prefrontal cortex underlie many mental health disorders. Since neuroinflammation is the most prominent effect observed in animal models exposed to particle pollution, we hypothesize that PM exposure will impair prefrontal cortex function by inducing inflammatory responses in the central nervous system. To address this hypothesis, we will 1) Assess prefrontal cortex function throughout adolescence in mice exposed to diesel exhaust particles and 2) Characterize the spatiotemporal dynamics of cellular and molecular pro-inflammatory mediators in the prefrontal cortex of juvenile mice exposed to different concentrations of diesel exhaust particles. The approach is innovative as it represents a departure from current research by shifting focus on adolescence as a window of susceptibility for the adverse health effects of particle pollution; and the prefrontal cortex as a target for PM-induced neurotoxicity. In addition, as part of the AREA grant, we will engage low-income Hispanic students in all aspect of the proposed research. To this extent, the proposed study will contribute knowledge about the environmental risk factors and biological mechanisms impacting mental health disorders with onset during adolescence; and will expose underrepresented undergraduate students to biomedical and environmental health research.