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Abstract
Ammonia is the primary basic gas in the atmosphere and has the most important role
in the neutralization of atmospheric acids generated by fossil fuel combustion. The
reaction product forms a NH(4)(+) aerosol, which is a major component of atmospheric
particulates. These NH(4)(+) particulates are part of atmospheric haze and may be
transported long distances from the production site before returning to the surface
by dry deposition or scavenged by precipitation. Animal production produces a significant
component of anthropogenic NH(3) emissions and the National Academy of Sciences concluded
that NH(3) emissions estimates from animal feeding operations have not been characterized
sufficiently, leading the US Environmental Protection Agency to institute studies
in the United States to obtain NH(3) emissions from animal feeding operations under
the US Environmental Protection Agency Air Consent Agreement. The objective of this
study is to obtain additional broiler NH(3) emissions estimates using a backward Lagrangian
stochastic technique. This technique uses NH(3) concentrations measured upwind and
downwind of the farm, wind observations, and atmospheric dispersion model calculations
to obtain whole-farm emissions. Ammonia emissions were low at bird placement and increased
steadily after about the third week of growth. At the end of the flock (47 d, ~297,000
birds), cumulative emissions for the flock cycle period were 0.016 kg of NH(3).bird(-1).flock(-1).
Between-flock emissions, including bird harvest, cleanout, temporary storage of litter
outside of the buildings, and downtime (buildings closed), added another 0.003 kg
of NH(3).bird(-1).flock(-1). Emissions from this broiler farm were less than from
some eastern US broiler farms but were comparable to broiler farms in Europe. Based
on the results of this study and a similar winter study at this same farm, total flock
wintertime and summertime (flock cycle plus between-flock) NH(3) emissions from this
farm represented 7.8 and 8.3% of feed N as NH(3)-N, respectively, or an annual average
of 8.1%.