Abstract
There is an urgent need for accurate measurement for emissions of ammonia (NH(3)) and hydrogen sulfide (H(2)S) in dairy barns in order to obtain reliable emission inventories and to develop and evaluate abatement strategies. This experiment was performed on three dairy farms in central China during 14 consecutive days in the winter 2020. Concentrations of NH(3) and H(2)S were measured every two hours. The samples were taken inside and outside of barns from 7 sites at two heights (at floor and 1.5 over the floor). The results show that the average NH(3) concentration was 2.47 mg/m(3) with a maximum of 4.62 mg/m(3), while the average H(2)S concentration was 0.179 mg/m(3) with a maximum of 0.246 mg/m(3). Lactating cows produced significantly more NH(3) (3.73 mg/m(3) versus 2.34 mg/m(3)) and H(2)S (0.24 mg/m(3) versus 0.14 mg/m(3)) than non-lactating cows. NH(3) and H(2)S concentrations were higher at 0 m than at 1.5 m, especially during the day. In addition, the average daily emission rates per animal unit (AU = 500 kg weight) were 23.5 g and 0.21 g for NH(3) and H(2)S, respectively. The emission rate for NH(3) was then used to extrapolate the NH(3) emission from the Chinese dairy production. Our estimation for 2016 was 0.45 Tg, and it could reach 1.35 Tg by 2050. These numbers reflected our first attempt to calculate emission inventories for the Chinese dairy industry. Our results also suggest that more concrete measures must be taken to reduce the uncertainties of NH(3) emissions from dairy cow production in China.