Ammonia concentrations in a free-stall dairy barn

The paper presents the results of research on indoor ammonia (NH3) concentrations in the air in a free-stall barn. The differences in measurement results mainly depended on the season and weather conditions. The study also showed a significant correlation (P<0.01) between the NH3 concentration and temperature, relative humidity and air movement velocity inside the barn. The lowest NH3 concentration was recorded in the summer (0.0 ppm) in the presence of high air temperatures, low humidity and increased exchange of ventilated air. In winter during severe frosts, highest ammonia concentration (8.0 ppm) was noted, caused by limited ventilation. The highest daily ammonia concentration was usually recorded during the night. This was due to increased relative air humidity and low air velocities. It was concluded that the average level of ammonia of 2.73 ppm during the entire year was significantly below values defined as harmful for animals and people.