The Respiratory Effects Research Core conducts research on the acute and chronic effects of environmental factors on the human and the extent to which host factors modify response. The Exposure Assessment Research Core carries out research on the best methods and approaches for establishing true exposure to environmental agents or their byproducts and core scientists collaborate with other investigators on exposure assessment. The Cancer Research Core evaluates environmental causes of cancer and improved methods of exposure assessment for environmental carcinogens. Active areas of research in this core include looking at environmental exposures that alter the effectiveness of “cancer susceptibility” genes. Finally, Study Design and Statistical Methodology Research Core investigates design and statistical analysis issues related to epidemiologic studies.