Development of a Reference Artificial Swine Odor

N-butanol is used as a reference odor to train odor panelists and field odor sniffers to measure odor concentrations and intensities, respectively. It has different characteristics from that of livestock odors. Odors from headspace samples of stored swine manure and wastewater sludge were analyzed with GC/MS. Seventeen identified compounds were selected as candidate constituents of an artificial swine odor (ASO). Twenty-four formulations of these constituents were developed. Three trials were conducted to evaluate these 24 formulations based on six criteria: the formulation would be safe to human panelists, the odor character was similar to swine odor, the persistence was similar to that of livestock odor, and the formulation was chemically stable, would not contaminate the olfactometer, and was easy to prepare and apply. Tedlar bags were filled with 16 L of carbon-filtered air and 1.82 (L) ASO (equivalent to 40 ppm). Odor concentrations of all ASO samples were measured by an olfactometer. The most representative formulation contained reduced sulfur, fatty acid, aromatic alcohol, aliphatic hydrocarbon, indole, and aliphatic alcohol. The ASO character is similar to that of swine manure, has a similar detection threshold to n-butanol, has a low persistence, is safe for use by panelists, and does not contaminate the olfactometer.