Bias of Tedlar Bags in the Measurement of Agricultural Odorants

• Published in: Journal of environmental quality Vol. 35; no. 5; pp. 1668 - 1677
• Main Authors: Trabue, S.L, Anhalt, J.C, Zahn, J.A
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.09.2006; Crop Science Society of America; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; Air Pollutants - analysis; Air Pollutants - chemistry; analytical methods; Animal Husbandry; Animals; Applied sciences; Bias; Biological and medical sciences; Compressed air; Earth sciences; Earth, ocean, space; Emissions; Engineering and environment geology. Geothermics; Environmental Monitoring - instrumentation; Environmental Monitoring - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gases; Housing, Animal; Methods; odor compounds; odor emissions; Odorants - analysis; Odorants - prevention & control; Odors; Pollution; Pollution, environment geology; Reproducibility of Results; sampling; sorption; storage temperature; storage time; Swine; Olfactometry; Tube; Bias; Pollutant emission; Time dependence; Container; Detection limit; Volatile fatty acid; Agriculture; Sampling; Organic compounds; Dynamic characteristic; Nuisance; Hydrocarbon; Residence time; Thermodesorption; Bag; Volatile organic compound; Desorption; Acetamide; Pig barn; Gas chromatography; Dilution; Storage; Animal; Phenols; Headspace; Air pollution; Regulation; Acetic acid; Odor; Mass spectrometry; Contaminant
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2005.0370

Odor regulations typically specify the use of dynamic dilution olfactometery (DDO) as a method to quantify odor emissions, and Tedlar bags are the preferred holding container for grab samples. This study was conducted to determine if Tedlar bags affect the integrity of sampled air from animal operations. Air samples were collected simultaneously in both Tedlar bags and Tenax thermal desorption tubes. Sample sources originated from either a hydrocarbon-free air tank, dynamic headspace chamber (DHC), or swine-production facility, and were analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Several background contaminants were identified from Tedlar bags, which included the odorous compounds N, N-dimethyl acetamide (DMAC), acetic acid, and phenol. Samples from the DHC demonstrated that recovery of malodor compounds was dependent on residence time in the Tedlar bag with longer residence time leading to lower recovery. After 24 h of storage, recovery of C3-C6 volatile fatty acids (VFA) averaged 64%, 4-methylphenol and 4-ethylphenol averaged 10%, and indole and 3-methylindole were below the detection limits of GC-MS-O. The odor activity value (OAV) of grab samples collected in Tedlar bags were 33 to 65% lower following 24 h of storage. These results indicate that significant odorant bias occurs when using Tedlar bags for the sampling of odors from animal production facilities.