Characterization of Non-Methane Volatile Organic Compounds at Swine Facilities in Eastern North Carolina

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Title: Characterization of Non-Methane Volatile Organic Compounds at Swine Facilities in Eastern North Carolina
Author: Blunden, Jessica
Advisors: Viney P. Aneja, Committee Chair
Abstract: A total of 110 samples of volatile organic compounds (VOCs) were collected and analyzed in a field study to characterize such compounds emitted at six swine facilities in Eastern North Carolina between April 2002 and March 2003 as part of the Project OPEN (Odors, Pathogens, and Emissions of Nitrogen). Two baseline sites employed conventional lagoon and field spray technologies while four sites utilized various alternative 'Environmentally Superior Technologies' (ESTs) in an effort to substantially reduce gaseous compound emissions, odor, and pathogens from these swine facilities. More than 200 compounds, including various paraffins, alkynes, aromatics, esters, ethers, monoterpenes, alcohols, aldehydes, ketones, monoterpenes, halogenated hydrocarbons, phenols, and sulfides were identified and quantified by Gas Chromatographic/Flame Ionization Detection (GC/FID) analysis as well as confirmed and/or verified by Gas Chromatographic/Mass Spectrometry (GC/MS). GC/MS analysis of three particularly complex samples collected at one site assisted in providing identification and retention times for more than 20 sulfur type volatile organic compounds (VOCs) including methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide as well as many other VOCs. Carbonyl sulfide and carbon disulfide were positively identified by GC/MS analysis but were not identified by GC/FID due to their particular compound characteristics. The results of these samples were subsequently used as a source fingerprint to identify and/or verify these compounds in all other samples collected. Overall, the highest VOC concentration levels measured at each of the sites were in close proximity to the hog barns. The total measured VOCs at the hog barns were typically dominated by ethanol, methanol, acetaldehyde, and acetone. The combined overall contribution of these compounds in relation to total measured VOCs generally ranged from 46-94%. The highest concentration levels of both dimethyl sulfide and dimethyl disulfide, the most commonly detected sulfur type compounds, as well as 4-methylphenol, were also observed near the hog barns. Hazardous air pollutants measured were acetaldehyde, benzene, n-hexane, methanol, methyl ethyl ketone (MEK), styrene, toluene, 4-methylphenol and xylene (m-, p-, & o), which were identified in many of the samples. In many instances, acetaldehyde, styrene (which was determined to co-elute with heptanal), and MEK were all measured at levels higher than their respective U.S. ambient background concentrations. Acetaldehyde was also measured at levels above its reference concentration (10 ppbC) in many of the samples. Statistical analysis performed on 35 samples to test for possible relationships between various VOCs, meteorological parameters, and Scentometer and odor intensity ratings revealed that only hydrogen sulfide had a strong effect on both odor intensity levels and Scentometer ratings. Alcohols and measured organic sulfur compounds had slight to moderate positive relationships with Scentometer ratings.
Date: 2003-07-31
Degree: MS
Discipline: Marine, Earth and Atmospheric Sciences
URI: http://www.lib.ncsu.edu/resolver/1840.16/853


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