Odorous chemical emissions from livestock operations in United States

This study was an add-on study to the National Air Emission Monitoring Study (NAEMS) funded by USEPA. The objective of this study was to measure odor emissions and corresponding concentrations and emissions of target odorous gases. Odor and odorous gas measurements at four NAEMS sites (dairy barns in Wisconsin-WI5B and Indiana-IN5B, swine finisher barn in Indiana-IN3B and swine gestation/farrowing barns in Iowa-IA4B) were conducted during 17 months periods over ~1 year. Odorous gas samples were collected every two weeks using sorbent tubes and analyzed by the thermal desorption-GC-MS-Olfactometry. In this paper, we summarize measured gas concentrations and emissions of twenty odorous gases from four sites. Based on the one-year measurement for four selected sites, the average volatile fatty acids (VFAs) concentrations ranged between 1.1 and 98 μg dsm^-3. The average phenolics and indolics concentrations varied from 0.8 to 31.3 μg dsm^-3. The average sulfur containing compounds concentrations were from 0.02 to 1.5 μg dsm^-3. The total VOC emission rates for 20 compounds for four sites ranged between 33.9 and 743 mg/hr-AU. Only acetic acid (<;0.05) and propanoic acid (<;0.1) had a seasonal significant difference for IA4B. For IN3B, 4-ethyl phenol and indole and most of VFAs (except hexanoic and heptanoic acid) have the seasonal significant differences. At the WI5B dairy site, there were five VFAs (acetic, propanoic, 2-methyl propanoic, butyric and 3-methylbuanoic acid) and one phenolics (4-methyl phenol) showing a seasonal significant difference. Only three compounds (2-methoxyphenol, 1-(2-aminophenyl)-ethanone and indole) had a seasonal significant difference for IN5B. Between dairy sites (WI5B vs. IN5B), acetic, propanoic, 2-methyl propanoic, butyric, and 3-methyl butanoic acids were significantly different. Most of odorants were significantly different except heptanoic acid, 1-(2-aminophenyl)-ethanone an- - d 3-methyl indole, between the two swine sites (IA4B vs. IN3B). Between the two different species (Dairy vs. Swine), five odorants including acetic and heptanoic acid, phenol, 4-ethylphenol, 1-(2-aminophenyl) ethanone were not significantly different, whereas the other 10 compounds measured were significantly different between swine and dairy.