Control of ammonia air pollution through the management of thermal processes in cowsheds.

Experimental researches performed in manufacturing cowsheds have demonstrated a variation of ammonia concentration and the factors influencing this most during different periods of the year. The process of ammonia evaporation from manure is influenced by many varying and interrelated factors with temperature and the intensity of air ventilation being the most critical ones. The influence of these factors on the process of ammonia evaporation was established by laboratory researches. An increase in temperature results in an exponential increase in ammonia emission, whereas the dependence of the emission on the air velocity is best expressed by a second degree polynomial. The results obtained may be used as a forecast of the ammonia emissions from cowsheds during different periods of the year. Intensive ventilation is required for the removal of excess moisture from the housing, and this limits the possibilities to reduce ammonia emissions by controlling the intensity of ventilation. A reduction in the amount of ventilation is only recommended if the air quality indices meet the requirements applied to the housing. Better opportunities to reduce ammonia emissions are provided through management of the thermal processes in a cowshed. If the average annual air temperature (11.3°C) is reduced by one degree in a cubicle housing cowshed, the ammonia emissions will decrease by 10%.