Submitted to: Aerosol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2007
Publication Date: 5/1/2007
Citation: Purdy, C.W., Clark, R.N., Straus, D.C. 2007. Analysis of aerosolized particulates of feedyards located in the Southern High Plains of Texas. Aerosol Science and Technology. 41:497-509.
Interpretive Summary: Dust is a major problem of concentrated animal feeding operations (CAFO). It is especially severe in cattle feeding operations located in the semiarid High Plains of Texas where the majority of large feedyards (FY) are located within a 240 mile radius of Amarillo, Texas. It is a nuisance to downwind neighbors, and the Environmental Protection Agency (EPA) has been mandated by Congress to determine the extent of air pollution, and if excessive, help reduce the pollution through state and federal cooperation for the welfare of the public. Very little information is published in peer reviewed journals concerning the nature of feedyard aerosols. We determined the quantity of PM10 dust (mean µg/meter3 of air) upwind, 94 (±17), downwind, 269 (±32), winter, 98 (±13), summer, 262 (±34) and FY1, 218 (±38), FY2, 226 (±52), FY3, 210 (±39), and FY5, 66 (±9); PM2.5 (mean µg/m3) FY1, 24 (±2), FY2, 25 (±5), FY3, 27 (±5), and FY5, 10 (±1). Size of the dust particle (geometric mean size range 0.71 [±1.7] to 2.02 [±1.7] µm) emission was also analyzed from 4 large feedyards in the winter and summer. We also determined the number (colony forming units [CFU]/meter3 of air) of non-respirable microbes, mean 880 (±119) CFU/meter3 and respirable microbes, mean 676 (±119) CFU/meter3 in the feedyards. It was concluded that summer and downwind dust concentrations were higher than those collected in the winter and upwind. Three of four feedyards analyzed for particulates exceeded the EPA 24 hour PM10 standard of 150 µg/m3 and none exceeded the 24 hour PM2.5 standard of 65 µg/m3. These data are important to the general public, EPA, and to the feedyard owner.
Technical Abstract: The upwind and downwind ambient aerosols of four large feedyards located in the southern High Plains of Texas were analyzed for the concentration of particles (µg/m3 of air), size of particles (µm), and the number of microbes (colony forming units [CFU/m3] in the winter and summer. Aerosol samples were collected using high volume sequential reference ambient air samplers, PM10 and PM2.5, biological cascade impactors, and other air monitoring devices, all of which were supported by a portable weather station. Overall statistical (P > 0.001) model statement (GLM) PM10 (mean µg/m3) data for: upwind, 94 (±17), downwind, 269 (±32), winter, 98 (±13), summer, 262 (±34), Feedyard 1 (FY1), 218 (±38), FY2, 226 (±52), FY3, 210 (±39), and FY5, 66 (±9); PM2.5 (mean µg/m3) data for: upwind, 18 (±3), downwind, 25 (±3), winter, 15 (±1), summer, 28 (±3), FY1, 24 (±2), FY2, 25 (±5), FY3, 27 (±5), and FY5, 10 (±1). GLM (P > 0.0001) for cascade impactor (all aerobic bacteria, Enterococcus spp, and fungi) mean respirable and non-respirable particles=colony forming units/m3 of air: non-respirable, 880 (±119), respirable, 676 (±74). In conclusion, the following environmental impact was determined. The PM10 geometric mean sizes (±GSD) of particles were analyzed in aerosols of the feedyards (range 1.782 [±1.7] to 2.02 [±1.74] µm) and PM2.5 geometric mean size particles were determined (range 0.66 [±1.76] to 0.71 [±1.71] µm). Three of four feedyards were non-compliant for the Environmental Protection Agency (EPA) standard (150µg/m3/24 h) for PM10 particles and 4 feedyards were compliant for the EPA standard (65 µg/m3/24 h) for PM2.5 particles.