Using passive flux samplers to determine the ammonia emission from mechanically ventilated animal houses

Ammonia emissions from animal houses are an important environmental issue in the Netherlands. The current technique in the Netherlands to measure ammonia emissions in mechanically ventilated animal houses is the chemiluminescence method (using a NOx monitor after conversion of NH3 to NO). During campaigns to measure emissions from animal houses, it became clear that management is an important factor in determining the emission level. Differences between animal houses of the same type and kind of animal may differ more than the variation in time and season within one animal house. These management related differences in emission factors point at the need to measure more animal houses during a shorter period. This stresses the need for development of flexible methods to be used in short term measurements, which allows monitoring the ammonia emission from a larger number of animal buildings per year. In this paper, a practical farm with different housing systems and two types of ventilation shafts (with and without a lid in the ventilation shaft to regulate the temperature inside the animal house) was selected to test theperformance of passive flux samplers to measure the ammonia emission from mechanically ventilated animal houses. A statistical t-test shows that the differences between passive flux samplers and the reference method are not significant at the 95% significance level when combining all measurements. The use of a lid in the ventilation shaft improves the correlation between passive flux samplers and the reference method. As a result of these measurements, passive flux samplers are presented as an alternative to measure the ammonia emission from mechanically ventilated animal houses.