Determination of particulate emissions from confined animal housing.

摘要

Determining particulate emission from mechanically ventilated confined animal feeding buildings is a challenging undertaking. This is due to the relatively large particle sizes involved, wide size range and difficulties in measurement of the ventilation rate of the building. This study seeks to address these issues by looking at the three critical measurements used in determining particulate emissions: total suspended particulates (TSP), particle size and ventilation rate. A new TSP sampling system was developed and tested in a controlled environment. This system appeared to perform as expected based on existing literature. It was fairly easy to use and its low cost suggests that further study is warranted. Measurement of particle size for agricultural particles is difficult since most of the instrumentation is designed for laboratory work or for particles smaller than those encountered in these settings. Several instruments were used to measure particle sizes. As expected many of the samplers designed for ambient sampling failed due to clogged nozzles or overloaded impactors. The final results focused on three instruments: the TSI APS, TSI Aerosizer DSP and the Coulter Multisizer. While the relative performance of each instrument was generally as expected, none appeared to have a distinct edge. The effective particle size range of the Coulter and the APS can limit their usefulness in many animal environments. Based on the experience during this study, it seems future research is needed for collecting particle samples in the field and measuring their size in the laboratory. For ventilation rate measurement a small vane anemometer was tested on three common fan sizes. Results showed reasonable performance but the need for field calibration and the need to examine environmental impacts on the long-term usefulness of these anemometers. This study highlighted a number of problems with sampling particles above 10 microm. Agreement within the research community is needed for developing a functional definition of TSP so that an appropriate sampling method can be established for confined animal buildings.