Date of Award:

5-2010

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Advisor/Chair:

Dr. Randal S. Martin

Abstract

This study was conducted in order to compare and evaluate a variety of ammonia (NH3) measurement techniques for determination of ambient gas phase concentration and evaluation of system fluxes. This was accomplished by measuring NH3 emitted from area sources within two dairies, one located in south-central Idaho and another in central California. The measurement techniques utilized included: an array of passive diffusion samplers, a single annular denuder system, a single or paired Fourier transform infrared spectrometer(s) (FTIR), a paired (upwind and downwind) set of differential optical absorption spectrometers (DOAS), and a portable wind tunnel in conjunction with a chemiluminescence monitor. The concentrations measured were manipulated by methods of inverse modeling using the ISCST3, AERMOD, and WindTrax models to yield estimated emission rates for individual sources, as well as an overall dairy emission rate. Furthermore, a comparison of the different techniques took place, and it was concluded that in the context of measuring agricultural area sources, the spectroscopy techniques, FTIR and DOAS, were likely the most desirable systems. This conclusion was based on the systems' ability to yield high precision, path integrated concentration measurements that do not require actual collection of sample. However, as long as a proper deployment scheme is utilized, the passive diffusion samplers also offered a viable option, especially when funding is limited.

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