Gaseous emissions from outdoor concrete yards used by livestock

Measurements of ammonia (NH 3 ), nitrous oxide (N 2 O) and methane (CH 4 ) were made from 11 outdoor concrete yards used by livestock. Measurements of NH 3 emission were made using the equilibrium concentration technique while closed chambers were used to measure N 2 O and CH 4 emissions. Outdoor yards used by livestock proved to be an important source of NH 3 emission. Greatest emission rates were measured from dairy cow feeding yards, with a mean of 690 mg NH 3 -N m −2 h −1 . Smaller emission rates were measured from sheep handling areas, dairy cow collecting yards, beef feeding yards and a pig loading area, with respective mean emission rates of 440, 280, 220 and 140 mg NH 3 -N m −2 h −1 . Emission rates of N 2 O and CH 4 were much smaller and for CH 4 , in particular, emission rates were influenced greatly by the presence or absence of dung on the measurement area.