Exposure to air pollutants and agricultural pesticides have been linked to adverse respiratory outcomes in children such as asthma. The public health impacts of these exposures are higher in rural areas with high air pollution burdens and heavy agricultural pesticide use. This dissertation is composed of three research studies and examines respiratory health impacts of air pollutant and pesticide exposure in the rural San Joaquin Valley and Salinas Valley, California communities. The first research study examined the association between regulatory and citizen science monitoring of particulate matter less than 2.5 microns in diameter (PM2.5) with asthma and other respiratory emergency department (ED) visits by children residing in Fresno County, California. PM2.5 monitoring data was obtained through the UC Merced San Joaquin Valley Center for Air Injustice Reduction (SJV-CAIR) and hospital ED visit information was obtained from the Fresno County Department of Public Health and Valley Children’s Hospital. Bayesian Poisson spatiotemporal conditional autoregressive models, which accounted for spatial PM variability, were used to analyze the relationship between PM2.5 and pediatric ED visits. The second study examined measurements of biomarkers of response to air pollution in urine samples collected from 64 parent-child dyads participating in the San Joaquin Valley Pollution and Health Environmental Research (SPHERE) study. The biomarkers included indicators of oxidative stress, inflammation, and lung cell injury (8-isoprostane, 8-hydroxy-2'-deoxyguanosine, prostaglandin E2, club cell protein 16). This study also examined the association of these biomarkers with measurements of indoor air pollutants (PM2.5, nitrogen dioxide, and ozone) and for a subset of adults and children, temporal variability over 4 consecutive days. The third study examined the association between potential exposure to nearby agricultural pesticide use with reported respiratory symptoms and lung function measurements in children residing in the Salinas Valley, California. This study used information on respiratory health in seven-year-old children participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study and agricultural pesticide use information from the California Department of Pesticide Regulation Pesticide Use Reporting System. Bayesian hierarchical models were used to examine the associations between nearby pesticide use and respiratory outcomes. This dissertation helps build a broader understanding of how environmental exposures potentially impact respiratory health outcomes. Thus, this dissertation generates new knowledge that can provide insights for public health interventions and policy development, both which are needed to improve the well-being of children across California and beyond.