In the first dataset, for each hour, the NH3 emission rate (ER, g h−1) was calculated according to Eq. (1). The average NH3 EF (kg year−1 (animal place)−1) was then calculated (Eq. (2)) by taking the mean over all the (N) NH3 emission rates and converting this mean from g h−1 to kg year−1 (animal place)−1. In the second dataset, the hourly NH3 emission rates and the average NH3 EF were calculated in the same way, except that no correction for incoming NH3 concentrations was made.