Characterization and concentration of particulate matters emitted from confinement animal buildings.

摘要

Many studies have been conducted to quantify total dust emissions from confinement animal buildings, but the dust emission was not sufficiently addressed due to absence of standard measurement methods and a lack of representative data. This study investigated chemical, physical and biological properties of dusts collected from various types of concentrated animal feeding operations with three seasons for better understanding of dust emissions. The primary objective of this study is to characterize typical dust particles emitted from confinement animal buildings.;Firstly, ammonia and odor release rates were determined on dusts from various types of animal production buildings. A cylindrical convective chamber was developed and then ammonia and odorous gases adsorbed in animal building dust were extracted by a low-temperature thermal desorption technique in the chamber. The highest ammonia emissions were found from swine building dust (44.9-382.5 mug/gram dust) followed by poultry building dust (26.0-133.2 mug/gram dust) and beef cattle building dusts (6.6-121.1 mug/gram dust).;Secondly, monitoring of particle size distributions (PSDs) of dust emitted from animal buildings were conducted using a Coulter Multisizer, a Malvern Mastersizer, a Horiba, and an Aerosizer DSP. The instrumental performance of the PSD analyzers was examined with known-sizes of mono-dispersed particles before field data collection. The highest accuracy was found in the Coulter Multisizer. Measured particle size distributions from animal buildings varied with type of animal housing (swine finishing, farrowing, gestation, poultry layer hens, and turkey broilers) and applied particle sizing instruments. The average value of mass median diameter ranged from 8.6mum to 19.9 mum. The mass concentrations of total suspended particles showed significant seasonal variation from all types of animal facilities ranging from 0.38 +/- 0.04 mg/m3 (swine gestation/hot weather) to 10.90 +/- 3.91 mg/m3 (turkey broiler/cold weather).;Third, seasonal bioaerosol measurements focusing on airborne bacterial particles were performed using a six-stage cascade impactor from nine different animal farms (swine finishing, farrowing, and layer hen housing). The measured bioaerosol concentrations varied from 12,000 to 28,000 CFU/m3 showing seasonal variation from each animal facility. The seasonal variation of bioaerosol concentrations was likely caused from the different levels of animal building ventilation.