The Atmospheric Turbulence and Diffusion Division (ATDD) is one of several field divisions of NOAA's Air Resources Laboratory, headquartered in Silver Spring, MD (see Division Hierarchy). ATDD began as a Weather Bureau Special Projects research office established in 1948 under Atomic Energy Commission sponsorship in Oak Ridge, TN, and still serves as a source of meteorological information and expertise for the U. S. Department of Energy and its contractors in Oak Ridge. However, ATDD's main function is to perform air quality and climate-related research directed toward issues of national and global importance. Emphasis is on the lower atmosphere. Air quality objectives are to develop better methods for predicting transport, dispersion, and air-surface exchange of air pollutants; to extend the applicability of these methods to increasingly realistic situations including nighttime cases, complex terrain, and non-uniform surfaces; and to test the methods against data to determine the confidence limits and uncertainties which apply. Climate objectives include reference-grade measurement of climate change and related physical and chemical processes. ATDD has a permanent staff of 30 (primarily Federal and contract), including thirteen scientists, eight engineers, six scientific and technical support staff, and three administrative support staff. We frequently host graduate students, post-doctoral fellows, and international visitors for varying intervals. Research is performed with the aid of personnel of the Independent Environmental Assessment and Verification (IEAV) division of Oak Ridge Associated Universities (ORAU), and in close collaboration with scientists and engineers from Oak Ridge National Laboratory (ORNL) and numerous other organizations, government agencies, universities, and private research institutions.

ATDD is located at 456 South Illinois Avenue in Oak Ridge, Tennessee, with a permanent research station about five miles away, within Oak Ridge National Laboratory's Walker Branch Watershed forested experimental area. Important on-site facilities include a wind tunnel laboratory, machine shop, electronics lab, and chemical instruments lab (all with design and fabrication capabilities), and a specialized library.