|Straus, David - TEXAS TECH|
Submitted to: American Association for Aerosol Research
Publication Type: Abstract Only
Publication Acceptance Date: October 24, 2003
Publication Date: October 24, 2003
Citation: Purdy, C.W., Rice, W.C., Straus, D.C. 2003. Aerosol particulates of feedyards on the Southern Great Plains. In: Proceedings of American Association for Aerosol Research. October 20-24, 2003. Anaheim, California. p.106. Technical Abstract: Concentrated animal feeding operations (CAFO) feedyards located in the Southern High Plains are known for their dusty conditions. The objective of this study was to determine the size of dust particles and the concentration of dust per 24 hr of ambient air over an eight day period in four large feedyards. Andersen RASS 300 series of samplers PM2.5 (two) and PM10 (two) [16.67 L/min or 24 m3/24 hrs] were used to collected dust at a height of 2 m. All other instruments collected dust at a height of 1 m. Two cyclone instruments (18.3 L/min) were used to measure the concentration of dust in mg/24 hrs and size of particles from 0.32 micron through 5.4 micron. The instruments were placed upwind and downwind outside the perimeter fence of the feedyard. Mean dust concentrations of particles 10 micron or more were significantly greater when collected downwind compared to the the upwind positions in the feedyards. A pattern of greater dust concentration in the air usually occurred between 17:00 to 20:00 hrs due to increased activity of the cattle. The mean upwind RASS PM10 collection was 1.5 mg/24 hr period compared to 3.3 mg/24 hr downwind, and the mean PM2.5 collection was 0.4 mg/24 hr for both upwind and downwind. The cyclone mean downwind feedyard collection data were (5.6 mg/stage 1 [size particles, 5.4 micron in diameter]), 0.72 mg/stage 2 [2.1 micron]), 0.7 mg/stage 3 [1.4 micron], 0.40 mg/stage 4 [0.65 micron]), and 0.28 mg/stage 5 [0.32 micron]; mean upwind data were (2.5 mg/stage 1 [5.4 micron]), 0.37 mg/stage 2 [2.1 micron]), 0.52 mg/stage 3 [1.4 micron], 0.44 mg/stage 4 [0.65 micron]), and 0.36 mg/stage 5 [0.32 micron]. The meteorological data collected for the four feedyards were: wind speed, mean, 3.96 m/s (min, 0.1 m/s & max, 12.4 m/s); wind direction was 12 days out of the North and 28 days out of the Southeast; humidity (min, 5.9 % RH & max, 97.5 % RH); ambient air temperature, mean, 7 degrees C (min, -15.6 degrees C & max, 29.1 degrees C). In conclusion, it was determined that feedyards normally generate dust particles in the size range of 10 micron or greater at a 2 m height, and that downwind carries a greater concentration of dust than upwind.