ABSTRACT
Bundy[7] surveyed 200 swine-farrowing houses and deter-
mined that the average NH3 concentration was 11.4 ppm
from December to February and 6.9 ppm from March to
May. Clark and McQuitty[3] studied the air quality in six
Alberta commercial free-stall dairy barns and found that
the NH3 was present in all six barns and the overall mean
values ranged from 7 to 20 ppm. Also, McQuitty et al.[8]
found an average ammonia concentration of 33 ppm in the
exhaust air of three commercial poultry laying barns during
winter conditions.
