The ammonia concentration and odor threshold levels were measured in the ambient air of four stages of the production unit and those measures were compared. Air samples were taken in different rooms of the building over a period of 11 months for odor threshold evaluation and the ammonia concentration were measured concurrently. The results of the comparison showed that the ammonia concentration is not a good indicator of the odor threshold when considering all production stages. However, correlation were obtained between ammonia concentration and odor threshold for the gestation and grower rooms within a given age group. Correlation could not be obtained for the farrowing and nursery rooms.
As mentioned in many publications, ammonia concentration cannot be used as an indicator of odor concentration. Even if the authors mentioned that ammonia could be correlated for gestation and grower groups, the pigs’ age has to be considered and other testing would have to be done for different production management types (feed, manure handling inside, feed and water equipment).