Ammonia Concentrations and Emissions at Two Commercial Manure-Belt Layer Houses with Mixed Tunnel and Cross Ventilation

Abstract

HighlightsAnnual average NH3 concentrations in two retrofitted manure-belt layer houses were 4.0 ±3.3 and 5.2 ±3.0 ppmv.Seasonal and diurnal variations were observed for NH3 concentrations (higher in colder seasons and early morning).Annual average NH3 emission rates from the two layer houses were 0.081 ±0.004 and 0.099 ±0.004 g d-1 hen-1.No consistent pattern was found for either seasonal or diurnal variations in NH3 emission rates.Abstract. Ammonia emission measurements at poultry houses are necessary to assess air quality and emission factors associated with poultry operations, but no data have been reported for manure-belt layer houses retrofitted from high-rise layer houses. Two commercial retrofitted manure-belt layer houses (both 121.9 m long, 19.5 m wide, and 7.7 m high; 170,000 bird nominal capacity each) in Ohio with mixed usage of tunnel and cross ventilation systems were continuously monitored for one year. The daily averages of the exhaust NH3 concentrations varied from 0.03 to 17.7 ppmv in house 1 and 0.37 to 14.4 ppmv in house 2 with annual means (±SD) of 4.0 ±3.3 and 5.2 ±3.0 ppmv, respectively. The NH3 emission factors based on the full year of data for houses 1 and 2 were 0.081 ±0.004 and 0.099 ±0.004 g d-1 hen-1 (12.5 ±10.1 and 15.2 ±10.6 kg d-1 house-1 or 24.9 ±20.0 and 31.1 ±23.4 g d-1 AU-1), respectively. Seasonal variations were observed for NH3 concentrations, with higher concentrations in winter and lower concentrations in summer. Within a day, NH3 concentrations were highest from 4:00 to 8:00 and lowest from 16:00 to 20:00. No consistent pattern was observed for seasonal or diurnal variations of NH3 emission rates. Higher NH3 concentrations and emissions were observed at the east and west exhaust air streams of the houses compared to the north and south exhaust air streams due to the unique configuration of the ventilation systems. NH3 emission was correlated with exhaust absolute humidity, hen caloric intake, feed consumption, and protein percentage of feed. Keywords: Ammonia emission factor, Diurnal variation, High-rise, Retrofitted poultry house, Seasonal variation, Spatial variation.