Measurement Techniques and Models for Ammonia Emissions At the Farm Level

The unique chemical and physical properties of ammonia make it difficult to obtain accurate atmospheric measurements of concentrations and to determine representative emission rates. Ammonia is a diffusive gas and emissions are driven by the chemical and physical factors of solution concentration, solution hydrogen ion concentration (pH), solution temperature, and ambient air turbulence (represented by windspeed). Influencing these factors during measurement results in non-representative estimates of concentrations and emissions. Mathematical relationships and field measurements of the effects of these factors have shown the problems associated with measurement influence. Noninterference techniques should be used in determination of emissions and for the verification of models; however, use of inappropriate, non-interference techniques will also give erroneous results. We made comparisons of emissions using appropriate and inappropriate measurement technologies. Large differences were obtained in emissions rates. Available statistical emissions models showed good fit to data although the geographical extent of usefulness was limited. A process model had slightly poorer fit to data but was not geographically limited.

⁽¹⁾ Telephone: (706) 769-5631 // Ext: 225