Characterization and quantification of airborne ammonia and volatile organic compounds from industrial animal agriculture.

摘要

Due to population pressures and the intensification of agricultural production, nuisance complaints with regard to odors from cattle facilities are on the rise, particularly in the Southern San Joaquin Valley of California. However, few data exist on the emissions of ammonia and volatile organic compounds from industrial cattle farming at the scale practiced in California and in the arid climate that typifies it, especially in relation to how these emissions participate in odor. To remedy this, various methods were developed and deployed at large commercial dairies and feedlots in California. To quantify airborne ammonia, a passive sampler was adapted, characterized and applied to various cattle facilities in different seasons. Inexpensive to produce and analyze, the samplers made it possible to collect samples in a comprehensive array, and revealed wide ranges of ammonia concentrations from 0 to 950 μg m −3, depending on time of day, season and position relative to the area source. Ammonia concentrations were not high enough, however, to account for odor. To characterize and quantify volatile compounds that may participate in odor, a method was developed to collect air samples from dairies through sorbent tubes that were analyzed via thermal desorption-gas chromatography-olfactometry-mass spectrometry. Applied to a large commercial dairy, the method identified 35 compounds at concentrations from 0.08 to 747.76 μg m−3, including acids, esters, alcohols, aldehydes, ketones, halogenates, amines and hydrocarbons.