ABSTRACT Childhood obesity is a major public health threat with rates increasing at an alarming rate worldwide. Currently 22.4% of children and adolescents are obese, approximately 16.7 million, with rates of obesity increasing in all age groups in the pediatric population. Obese children are more likely to be diagnosed with several major morbidities (hypertension, hyperlipidemia, coronary artery disease, and diabetes). The estimated annual health care costs of obesity- related illness are a staggering $190.2 billion or nearly 21% of annual medical spending in the United States. Household air pollution (HAP) is a term that describes the health and environmental impacts of pollutants produced from incomplete combustion of solid fuels such as wood, coal, charcoal, animal dung, crop wastes burnt on open fires or wood-burning stoves in poorly ventilated homes and releases suspended particulate matter (PM). There are few studies examining the role of household air pollution including PM2.5 in cardiovascular risk in the setting of pediatric obesity. An important component of cardiovascular health is a diurnal variation of blood pressure, where nocturnal levels are approximately 20% lower than daytime values. The absence of nocturnal BP-dipping in childhood may be an important indicator of early disease risks and our team has recently published evidence that childhood obesity is associated with non-dipping. The specific project proposed here will test the hypothesis that exposure to household air pollution increases cardiovascular risk in obese children through an inflammation- related disruption in diurnal BP regulation. This project will recruit patients aged 10-18 to define relationships between at-home air quality and hypertension risk factors. A pilot study to determine the impact of high efficacy particulate matter (HEPA) filtration units on air quality exposure and health risks will be measured in these patients as well. This research addresses a significant public health issue by understanding and identifying environmental exposures in a vulnerable high-risk group of rural children in order to develop new treatments to improve their health.