With ER: emission rate (g h−1), Q: ventilation rate (m3 h−1), Co: outgoing NH3 concentration (mg m−3), Ci: incoming NH3 concentration (mg m−3), a: number of animal places and N: number of emission rates.
Based on these calculations, the pig unit in dataset 1 had an EF of 2.16 kg NH3 year−1 (animal place)−1 and the pig unit in dataset 2 had an EF of 1.01 kg NH3 year−1 (animal place)−1.