39 years of research activities as a Commissioned Officer in the U. S. Public Health Service (assigned to USEPA) and an environmental engineer for the National Risk Management Laboratory, Office of Research and Development, U. S. Environmental Protection Agency. These activities have been concentrating on the development and application of measurement techniques to evaluate air pollution sources and controls. Particulate sampling methods include cascade impactors and cyclones for particle sizing, high volume mass samplers for exhaust stacks from high efficiency control devices and fugitive source plume measurements. Recent efforts have included the development of on-road sampling methods for heavy-duty diesel trucks and the application of open-path Fourier transform infrared spectrometry and other optical methods to agricultural, vehicular and other fugitive gas and particle plumes.