Ammonia in the air exhausted from animal containment facilities may be
removed by scrubbing the air with a solution of a suitable salt of an
acidic proton donor such as alum. Ammonia may be removed from the air
within any enclosed animal building which includes at least one air inlet
and at least one outlet, a ventilation system having an air mover
effective to draw fresh air into the building through the inlet and
exhaust contaminated air through the outlet, and an air scrubber in
communication with the outlet. Prior to exhausting the air into the
environment, the air is passed through the scrubber where it is contacted
with a solution of the salt of an acidic proton donor effective for
flocculating ammonia therein. The flocculated ammonia may then be removed
from the solution, which may then be recycled to the scrubber.