Submitted to: Proceedings Workshop on Agricultural Air Quality: State of the Science
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2006
Publication Date: June 5, 2006
Citation: Mcconnell, L.L., Trabue, S.L. 2006. Analytical challenges in measuring odorant emissions from animal operations. Proceedings Workshop on Agricultural Air Quality: State of the Science. p. 153-157.
Accurate measurement of odorant emissions associated with animal agriculture is a challenging undertaking as accurate air concentration data is required. Quantitation of the large number of odorants associated with animal manures is difficult due to the physical/chemical properties of the analytes (highly polar, reactive and volatile), the variability of the ambient air matrix (temperature, relative humidity and dust levels), and the difficulty in creating analytical standards for quantification. Odorants fall into a number of organic compound classes, i.e., sulfides, mercaptans, amines, phenols, indoles and fatty acids, and include inorganic chemicals like hydrogen sulfide and ammonia. The large range of compound classes, polarity, reactivity and volatility require that several analytical methods be used. In order to accurately determine emission factors for even selected odorants, some basic QA/QC principles are required to validate the effectiveness of an analytical method. One of the most important factors in assessing the effectiveness of an odorant’s analysis is to determine the effect of humidity on analyte collection efficiency and instrument performance. For highly polar analytes collection efficiency on a sorbent material may be drastically decreased under high humidity conditions. In addition, recovery and analysis of polar compounds in canisters systems are also affected by ambient humidity levels. Another critical issue is the development of accurate calibration curves for analyte quantitation. For example, use of permeation device to create a methyl mercaptan standard gas is complicated by the reaction in the presence of oxygen and light to form dimethyldisulfide, another important odorant.