Ammonia emissions from US poultry houses: Part II - Layer houses

An ongoing project of monitoring ammonia (NH3) emissions from U.S. layer houses with two different housing and management schemes is reported in this paper. Ammonia and carbon dioxide concentration levels were collected bi-weekly from each house with portable monitoring units (PMUs). There existed substantial seasonal variations in NH3 emission from the layer houses. Specifically, daily mean NH3 concentrations ranged from 1 to 7 ppm in the manure belt house and from 9 to 108 ppm in the high-rise house. The NH3 emission rates averaged 6 mg/hr-hen or 44 g/d-500kg over a 12-month monitoring period (February 2002 - March 2003) for the manure belt house and 44 mg/h-hen or 331 g/d-500kg over a 10-month monitoring period (February - November 2002) for the high-rise house. Ammonia emission rates are higher in summer than in winter, although NH3 concentration may be much lower in summer.