Measurement of Ammonia Concentrations and Fluxes: Recent Examples Using Denuder and Chemiluminescence Technologies

This presentation will describe selected ongoing research projects that employ commercially available technologies for determination of atmospheric concentrations and fluxes of ammonia. Annular denuders are used in an ambient monitoring project to measure ammonia, ammonium aerosol, and acid gases at agricultural and non-agricultural sites in eastern North Carolina. Another project examines spatial gradients of ammonia concentrations in the vicinity of a swine production facility using passive diffusion samplers. A third project investigates air/surface exchange of ammonia above crop canopies using chemiluminescence analyzers as part of a modified Bowen-ratio flux measurement system. Methodology and selected results will be presented for each project and advantages/disadvantages of the respective ammonia measurement technologies will be discussed.

⁽¹⁾ E-mail: Walker.johnt@epa.gov