Improved, GC-Olfactometry Based, MalodorAssessment of Swine CAFOs Utilizing Novel AirSampling Technologies

摘要

GC-Olfactometry based odor profile work to date indicates that with increasing distancefrom high-density swine feeder operations the residual odor is increasingly defined by alimited number of high priority odorants. These ‘character defining’ odorants appear tobe dominated by compounds of relatively low volatility and high polarity. Recent worksuggests that, as previously shown for cattle CAFOs, p-cresol may carry much of theoverall odor impact, especially for the case of increasing distance from the source. Ifconfirmed, such prioritization questions the appropriateness of odor sampling protocolswhich are based on plastic sample bags. Several studies have shown that p-cresol andother high-impact, semi-volatile odorants are rapidly lost to the wall of the bag through‘scalping’ effects. This project was aimed at exploring alternative whole-air andanalytical sampling strategies which address these limitations of plastic sampling bags forCAFO odor assessment. This manuscript reports on preliminary design and feasibilitystudy results for two such alternative approaches. The first is an alternative whole-airsampling strategy based on at-source volatiles collection utilizing sorbent tubes, followedby at-instrument thermal desorption and air sample reconstitution. The second is theconcept of a time-indexed, moving film volatiles collecting cassette; enabling acontinuous ‘moving picture’ of the volatiles profile to be collected for any specificsample point over an extended period of time. The results to date suggest that the firsttechnique should enable improved precision for Dynamic Dilution Olfactometry basedodor assessment protocols. The second technique offers potential for off-setting thelimitations imposed by point-in-time sampling in relation to shifting meteorologicalconditions.