Solid-Phase Microextraction as a Novel Air Sampling Technology for Improved, GC--Olfactometry-Based Assessment of Livestock Odors

Abstract

Air sampling and characterization of odorous livestock gases is one of the most challenging analytical tasks. This is because of low concentrations, physicochemical properties, and problems with sample recoveries for typical odorants. Livestock operations emit a very complex mixture of volatile organic compounds (VOCs) and other gases. Many of these gases are odorous. Relatively little is known about the link between characteristic VOCs/gases and, specifically, about the impact of characteristic odorants downwind from sources. In this research, solid-phase microextraction (SPME) is used for field air sampling of odors downwind from swine and beef cattle operations. Sampling time ranges from 20 min to 1 h. Samples are analyzed using a commercial gas chromatography-mass spectrometry-olfactometry system. Odor profiling efforts are directed at odorant prioritization, with respect to distance from the source. The results indicate the odor downwind is increasingly defined by a smaller number of high-priority odorants. These "character defining" odorants appear to be dominated by compounds of relatively low volatility, high molecular weight, and high polarity. In particular, p-cresol alone appears to carry much of the overall odor impact for swine and beef cattle operations. Of particular interest is the character-defining odor impact of p-cresol as far as 16 km downwind of the nearest beef cattle feedlot. The findings are highly relevant to scientists and engineers working on improved air sampling and analysis protocols and on improved technologies for odor abatement. More research evaluating the use of p-cresol and a few other key odorants as a surrogate for overall odor dispersion modeling is warranted.

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

“…Recently, nearly 300 VOCs have been identified in headspace of swine manure (Lo et al, 2008). An increasing number of studies show that only a relatively small subset of VOCs, such as p-cresol and selected phenolics/indolics, volatile fatty acids, and sulfur VOCs, is responsible for the characteristic livestock odor Bulliner et al, 2006;Koziel et al, 2006;Laor et al, 2008). However, most of these odor-causing VOCs are polar, reactive, and highly sorptive onto surfaces of sampling media, which increases the challenge for their measurement.…”

Air Sampling and Analysis Method for Volatile Organic Compounds (VOCs) Related to Field-Scale Mortality Composting Operations

“…Solid phase microextraction (SPME) offers many advantages for air sampling, such as high precision and sensitivity, applicability to high-moisture samples, reusability, and compatibility with conventional analytical equipment (10)(11)(12)(13)(14)(15). SPME has been used successfully in field air sampling of various types of agricultural operations (16,17). A method is available using two different SPME fiber coatings for the analysis of propanoic acid, butyric acid, and sulfur compounds from waste treatment systems (18).…”

Surface Application of Soybean Peroxidase and Calcium Peroxide for Reducing Odorous VOC Emissions from Swine Manure Slurry

“…At the 4-ethylphenol concentrations observed in this research, 4-ethylphenol accounted for less than 1% of the overall OAV. Nevertheless, the statistically significant reductions of both 4-methylphenol and 4-ethylphenol is a promising observation related to the overall odor reduction efficacy of SBP+CaO 2 and the preeminence of 4-methylphenol as the characteristic downwind odorant of livestock facilities (Wright et al, 2005;Bulliner et al, 2006;Koziel et al, 2006).…”

“…Many VOCs are generated from the degradation of amino acids, which occurs both in the intestines of animals and during the anaerobic decomposition of manure (MataAlvarez et al, 2000;Kai and Schafer, 2004;Koziel et al, 2006;Cai et al, 2006;Chen et al, 2008). Commonly reported odorants from manure sources include ammonia, volatile fatty acids (VFA), sulfides, 4-methylphenol (aka pcresol), phenol, indole, and skatole.…”

“…Commonly reported odorants from manure sources include ammonia, volatile fatty acids (VFA), sulfides, 4-methylphenol (aka pcresol), phenol, indole, and skatole. While many odorous compounds are emitted from manure, the phenolic and indolic compounds have been shown most responsible for manure odors at distance from the source (Wright et al, 2005;Bulliner et al, 2006;Koziel et al, 2006;Parker, 2008).…”