Ammonia emission from a large mechanically-ventilated swine building during warm weather

Ammonia (NH3) emission from a grow-finish swine (Sus scrofa) building with an underfloor manure storage pit was evaluated during warm weather from 26 June to 25 September. Average daily mean (ADM, covering all measurement day s) outdoor temperature was 21.8 degrees C. Ammonia concentrations, ventilat ion rates, and temperatures were continuously measured or recorded and 88 d of reliable data were obtained. Air samples were taken at wall and pit exh aust fans and in the pit headspace. The NH3 concentrations were monitored o n-site with a chemiluminescence NH3 analyzer. Ventilation rates were calcul ated based on operation of five wall fans, four pit fans, and the fan stati c pressure. The NH3 emission rates were calculated by multiplying simultane ously measured NH3 concentrations and ventilation rates of wall and pit exh aust fans. The ADM of building NH3 concentration (mean concentration of all sampling locations) was 3.9 mg m(-3). The ADM building NH3 emission (sum o f the emissions from all ventilation fans) was 11.2 kg d(-1), equivalent to 145 g d(-1) per AU (animal unit = 500 kg animal weight). The ADM emission per AU was higher than other reported values, probably due to warmer temper atures and higher ventilation rates. The building NH3 concentrations were i nversely proportional to the indoor temperatures (r = -0.66) and ventilatio n rates (r = -0.59) and correlated well to total pig weight (r = 0.49). The building NH3 emission rates were correlated to total pig weights (r = 0.52 ) and ventilation rates (r = 0.41) and were not well correlated to indoor t emperatures (r = 0.12).