Researchers conduct observational human exposure studies to understand how and the extent to which people come into contact with chemicals and environmental stressors in their everyday lives, through the air they breathe, the food and liquids they consume, and the things they touch. This book looks at the U.S. Environmental Protection Agency's (EPA's) National Exposure Research Laboratory (NERL) which has conducted observational human exposure studies for several decades and uses the information and data from these studies to improve the Agency's understanding of human exposures to chemicals and other stressors and ultimately to support efforts to improve public health. This book consists of public documents which have been located, gathered, combined, reformatted, and enhanced with a subject index, selectively edited and bound to provide easy access.