|Todd, Richard - Rick|
Submitted to: Manure Management Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/30/2009
Publication Date: 9/28/2009
Citation: Paris, C.S., Parker, D.B., Cole, N.A., Todd, R.W., Caraway, E.A., Rhoades, M.B., Baniya, B., Brown, T.B. 2009. Comparison of ammonia emissions determined using different sampling methods. In: Proceedings of the Texas Animal Manure Management Issues Conference, September 28-30, 2009, Round Rock, Texas. p. 83-90. Interpretive Summary: Ammonia emissions from livestock feeding operations can represent a significant loss of valuable fertilizer nitrogen and can also contribute to air quality concerns. Emissions of ammonia are affected by factors such as diet, pen surface conditions, air temperature, wind speed, and atmospheric turbulence. Measuring ammonia emissions from open lots is very difficult. Because they are relatively inexpensive and easy to use, dynamic-flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations. However, placing a chamber on a pen surface alters factors such as surface temperature, air temperature, air humidity, wind speed and atmospheric turbulence: all factors that can significantly affect ammonia emissions. Therefore, we conducted a series of experiments to determine the effects of flux chambers or wind tunnels on ammonia emissions or water evaporation measured from standard solutions. In general, ammonia losses and water evaporation measured from pans covered with a flux chambers were significantly less than from pans with no flux chamber. Flux chambers should not be used to directly measure emission of ammonia from pen surfaces. It may be possible to develop correction factors based on water evaporation to correct emissions to values that are closer to field conditions.
Technical Abstract: Dynamic, flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations; however, ammonia emissions from the surfaces are affected by many factors which can be affected by the chamber. Ammonia emissions estimated using environmental flow-through chambers may be affected by air exchange rate; however, chamber fluxes have not been directly compared to the flux from the same source when unaffected by a chamber. We compared measured ammonia fluxes and water evaporation from an Environmental Protection Agency (EPA) flux chamber and West Texas A&M University wind tunnel using buffered ammonium sulfate solutions and distilled water. Emission rates were also measured in open pans in the laboratory and outside.