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Studies of steroid growth promoters from beef cattle feedyards have previously focused on effluent or surface runoff as the primary route of transport from animal feeding operations. There is potential for steroid transport via fugitive airborne particulate matter (PM) from cattle feedyards; therefore, the objective of this study was to characterize the occurrence and concentration of steroid growth promoters in PM from feedyards. Air sampling was conducted at commercial feedyards (n = 5) across the Southern Great Plains from 2010 to 2012. Total suspended particulates (TSP), PM₁₀, and PM_2.5 were collected for particle size analysis and steroid growth promoter analysis. Particle size distributions were generated from TSP samples only, while steroid analysis was conducted on extracts of PM samples using liquid chromatography mass spectrometry. Of seven targeted steroids, 17α-estradiol and estrone were the most …