Multidimensional Gas Chromatography−Olfactometry for the Identification and Prioritization of Malodors from Confined Animal Feeding Operations

Abstract

Odor profiling efforts were directed at applying to high-density livestock operations some of the lessons learned in resolving past, highly diverse, odor-focused investigations in the consumer product industry. Solid-phase microextraction (SPME) was used for field air sampling of odorous air near and downwind of a beef cattle feedyard and a swine finisher barn in Texas. Multidimensional gas chromatography-olfactometry (MDGC-O) was utilized in an attempt to define and prioritize the basic building blocks of odor character associated with these livestock operations. Although scores of potential odorant volatiles have been previously identified in high-density livestock operations, the odor profile results developed herein suggest that only a very few of these may constitute the preponderance of the odor complaints associated with these environments. This appeared to be especially true for the case of increasing distance from both cattle feedyard and swine barn facilities, with p-cresol consistently taking on the dominant odor impact role with ever increasing distance. In contrast, at- or near-site odor profiles were shown to be much more complex, with many of the well-known lower tier odorant compounds rising in relative significance. For the cattle feedyard at- or near-site odor profiles, trimethylamine was shown to represent a significantly greater individual odor impact relative to the more often cited livestock odorants such as hydrogen sulfide, the organic sulfides, and volatile fatty acids. This study demonstrates that SPME combined with a MDGC-O-mass spectrometry system can be used for the sampling, identification, and prioritization of odors associated with livestock.

Testing odorants recovery from a novel metallized fluorinated ethylene propylene gas sampling bag

“…Significant recovery decrease over time was observed in previous studies (Koziel et al, 2004;Parker et al, 2010;Mochalski et al, 2009;Trabue et al, 2006;Keener et al, 2002b).…”

“…Keener and Zhang had observed more than 90% loss for p-cresol, indole, and skatole after 4-hr storage in a Tedlar bag at 22°C, and significant loss of volatile fatty acids (VFAs) after a 24-hr storage (Keener et al, 2002b). Koziel et al reported 32.4% and 77.3% average losses for key odorants of 7 VFAs and 4 semiVOCs after 0.5-hr and 24-hr storage (Koziel et al, 2004). Similar results were reported by Trabue and Anhalt (2006) and Parker et al (2010).…”

Gas chromatography-olfactometry

“…This may be a mechanical valve [99,100] or a pneumatic switching system such as a Deans Switch [101,102]. These methods increase the complexity and expense of multidimensional systems, requiring extra equipment, but offer greater resolving power and flexibility.…”

“…Finally, hyphenating MDGC to a mass spectral detector as well as an olfactory port provides a very powerful identification tool [25,102,105,106].…”

Secondary organic aerosol from atmospheric photooxidation of indole

“…In concentrated animal feeding operations (CAFOs), indole is primarily emitted from animal waste (Yuan et al, 2017) and can contribute significantly to the malodours in cattle feed yards and swine facilities (Feilberg et al, 2010;Wright et al, 2005). While Yuan et al (2017) indicated that indole is emitted from dairy operations, beef feed yards, sheep feed yards, and chicken feed yards, the emission rate of indole from these sources was not quantified.…”