Ambient odour testing of concentrated animal feeding operations using field and laboratory olfactometers

Abstract

The Missouri Air Conservation Commission regulations include regulations that limit the amount of acceptable odor from confined animal feeding operations (CAFOs). The regulations concerning odor designate the use of a scentometer as a screening tool. The rules dictate that if an odor is detectable by an investigator at a dilution ratio of 5.4 using a scentometer then an air sample should be collected and sent to an olfactometry laboratory for an odor panel to determine the detection threshold and the intensity of the odor sample. The detection thresholds are determined following ASTM E679-91 and EN13725. The intensity is determined following ASTM E544-99. If the olfactometry laboratory determined the detection threshold of the sample to be above seven, then the CAFO would be in violation. If the olfactometry laboratory determined the intensity level to be above a level equivalent to 225 ppm of n-butanol, then the source of odor would be in violation. The CAFO odor rules came under scrutiny by representatives of the largest hog producer in the State of Missouri. Specifically, they argued that the detection threshold limit of seven in the CAFO portion of the rule was too low for the rule to realistically identify a violation. This paper presents the results of a study to find the appropriate regulatory level of odor as determined by laboratory olfactometry. The study took place from November 2001 to October 2002. Samples were collected from field locations that exhibited odor produced by confined animal feeding operations and from areas exhibiting no apparent odor. The odors were categorized based upon the scentometer level at which the odors were detectable, and then samples were sent to an odor evaluation laboratory for analysis by olfactometry.

Field Olfactometry Assessment of Dairy Manure Land Application Methods

“…Such a response is more appropriately identified as the RT, which is typically about half of the DT level in laboratory olfactometry. This would account for much of the discrepancy between lab and field olfactometry thresholds noted by Bokowa (2008), but alone cannot explain the magnitude of difference in our work, which is more similar to the findings of Newby and McGinley (2004)…”

“…Noteworthy is the discrepancy between laboratory log DT and fi eld log D/T odor panel values, which in most cases are more than an order of magnitude diff erent. Newby and McGinley (2004) likewise found laboratory TFC odor panel levels to be much higher than fi eld olfactometry readings and concluded that a laboratory DT of 110 was approximately equivalent to a fi eld olfactometry D/T level of 7:1. Th ough diff erences were not as pronounced, Bokowa (2008) reported that the NRO device gives signifi cantly (2× to 3×) lower odor detection threshold values than ambient air sampling with laboratory assessment.…”

Odor from anaerobic digestion of swine slurry: influence of pH, temperature and organic loading

“…Prior investigations show that Nasal Ranger equipment is efficient in the measurement of odors resulting from livestock production (Newby, 2004). Thus, it has less variability and correlation (R 2 = 0.49 to 0.51) with the information provided by dynamic olfactometry in the laboratory (Dynamic, Triangular Olfactometry Forced Choice), also that the variability of panelists' responses is low with both devices.…”

A Screening Tool for Selection of Field Odor Assessors

“…Odors may become an issue when a residential population is located near industrial facilities, such as food manufacturers, chemical factories, oil refineries, and rendering plants, 1 or agricultural activities, such as confined animal feeding operations, 2 composting facilities, 3 and land application of manure or biosolids. 4,5 Advanced sampling systems and chemical analyses increasingly are used to characterize odors at the source and downwind 6,7 but, nevertheless, sensory evaluations, either by laboratory olfactometers or by human field assessors, remain essential because of the difficulties in determining correlations between odor strength and offensiveness, and the concentrations of specific odorants in complex odorous mixtures.…”