Ammonia Contents and Desorption from Dusts Collected in Livestock Buildings

The objective of this study was to determine rates of ammonia desorption from sediment dust and ammonia levels in airborne dust in animal houses in order to explore the nature of ammonia in the dust particles. This is assumed to be important for obtaining better understanding of the role of dust in the perception of odor and the development of respiratory diseases in farmers’ lungs. Sediment dust samples were collected in swine and poultry houses. About 3 g of dust was packed between two glass fiber filters in a 37 mm dust sampler cassette and exposed to clean air at an airflow rate of 0.001m 3 min -1 . The ammonia emitted to the air was determined by using the 0.5% boric acid trap and indo-phenol method. On the basis of the obtained data, desorption models for ammonia desorption from the swine and the poultry dusts were developed. The results indicate that the ammonia molecules are strongly bound inside dust particles. The ammonia contents of airborne dust samples were determined by using distillation in alkaline water solution, the 0.5% boric acid trap and indo-phenol method. The ammonia contents in inhalable dust collected in dairy, poultry and farrowing houses ranged from 1 to 6 µg per mg of dust, i.e. 1,000 and 6,000 ppm on a weight basis, while about 7 µg NH3 per mg of dust, i.e. 7,000 ppm, was found in respirable dust. These results indicate that the dust particles are capable of carrying ammonia molecules. This may cause much higher local ammonia concentration at the points where the particles deposit, e.g. in the olfactory organ and the respiratory system, than it can cause by aerial ammonia concentration.