Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #201342
Title: Field sampling method for quantifying volatile sulfur compounds from animal feeding operations

Author
item Trabue, Steven - Steve
item Scoggin, Kenwood
item MITLOEHNER, FRANK - UNIVERSITY OF CALIFORNIA
item LI, HONG - IOWA STATE UNIVERSITY
item BURNS, ROBERT - IOWA STATE UNIVERSITY
item XIN, HONGWEI - IOWA STATE UNIVERSITY

Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2007
Publication Date: 5/1/2008
Citation: Trabue, S.L., Scoggin, K.D., Mitloehner, F., Li, H., Burns, R., Xin, H. 2008. Field sampling method for quantifying volatile sulfur compounds from animal feeding operations. Atmospheric Environment. 42:3332-3341.

Interpretive Summary: Volatile sulfur compounds (VSCs) are believed to be a major source of odor from animal feeding operations. However, little is known about volatile sulfur compounds in terms of compounds that are emitted and at what levels these compounds present at animal feeding operations. The reason for this lack of knowledge is due to challenges associated with both the sampling and analysis of these compounds in air. Challenges include both the reactivity and volatility of these compounds and the low concentration of these compounds in air. This paper presents information on a whole air sampling technique using fused silica lined canisters (FLS). The FSL canisters help to improve the stability of the most reactive sulfur compounds and collects whole air. The samples are analyzed on a gas chromatogram that has two detectors in parallel, one a pulsed flame photometric detector (PFPD) and the other mass spectrometer (MS). The PFPD is sensitive to sulfur compounds and when combined with a MS improved the sensitivity of the method for sulfur compounds. The method has detection limits in the sub-part per billion range for sulfur compounds which is well below the odor threshold for most sulfur compounds. Sampling in humid environments results in the rapid loss of both hydrogen sulfide and methanethiol. The stability of these compounds in canisters can be improved with the use of desiccants to remove moisture from the incoming air. Even with the use of desiccants, stability of hydrogen sulfide and methanethiol was still less than 24 h. Major odorous VSCs from swine manure included both methanethiol and dimethyl sulfide, while poultry litter was dominated by dimethyl trisulfide. Other VSCs above odor threshold values for swine manure included hydrogen sulfide, dimethyl disulfide, and dimethyl trisulfide, while poultry facilities had both methanethiol and dimethyl sulfide above odor threshold values. Volatile sulfur compounds were never detected above their odor threshold values for dairy cows or their fresh manure. Research results described in this report provides animal, environmental, and regulatory scientist and engineers’ valuable information on a technique that can measure volatile sulfur compounds in air.

Technical Abstract: Volatile sulfur compounds (VSCs) are a major class of chemicals associated with odor from animal feeding operations (AFO). Identifying and quantifying VSCs in air is challenging due to their volatility, reactivity, and low concentrations in ambient air. In the present study, a canister based method was used to allow for the analysis of VSCs in ambient air at the sub-part per billion volume range. This technique uses whole air sampling with fused silica lined (FSL) mini-canisters (1.4 L). Air samples from canisters are cryofocused onto the GC column and analyzed in parallel with a mass spectrometer (MS) and pulsed flame photometric detector (PFPD). The GC column effluent was split 20:1 between the MS and PFPD. The PFPD equimolar sulfur response enhanced quantitation and the location of sulfur peaks for mass spectral identity. Storage stability of hydrogen sulfide and methanethiol were problematic in humid air with losses of over 40% within 4 h. The use of calcium chloride as a desiccant improved stability, but recovery of hydrogen sulfide and methanethiol was still only 65% after 24 h of storage. Major odorous VSCs from swine manure included both methanethiol and dimethyl sulfide, while poultry litter was dominated by dimethyl trisulfide. Other VSCs above odor threshold values for swine manure included hydrogen sulfide, dimethyl disulfide, and dimethyl trisulfide, while poultry facilities had both methanethiol and dimethyl sulfide above odor threshold values. Volatile sulfur compounds were never detected above their odor threshold values for dairy cows or their fresh manure.