The report describes setting priorities for controlling fugitive particulate emissions. Emission rate estimates of suspended particulates from open sources in the U.S. were obtained from emission factors and source extents in the literature. Major open sources, with their estimated total emission rates (in millions of tons per year), are: unpaved roads, 300; construction activities, 30; wind erosion of cropland, 40; paved roads, 8; and wildfires, agricultural tilling, and mineral extraction, each 3. (For comparison, point sources of particulates in the U.S. are estimated to emit about 20 million tons per year). Open source emissions are estimated for each state. Most open source rates are correlated with each other and state population is strongly correlated with the total rate and with most of the source types. The use of cost effectiveness is compared. Paving unpaved roads should reduce emissions at an average of less than $0.01/lb for such states as RI and DE (for rural roads) and AK, AZ, CA, DE, MI, NV, PA, CO, FL, IL, IN, KY, MD, MA, NJ, NM, OH, RI, TN, TX, UT, VA, WA, and WV (for remaining unpaved municipal roads). The control of unpaved road emissions (generally by paving), especially in cities, and the control of emissions from construction activities are concluded to deserve high priority in the effort to reduce total suspended particulate levels.