84th AMS Annual Meeting

Monday, 12 January 2004
The utilization of ion mobility spectrometry and annular denuder techniques to explore the dry deposition of ammonia in coastal ecosystems
Hall 4AB
LaToya Myles, Florida A&M University, Tallahassee, FL; and L. Robinson and T. P. Meyers
Ammonia emissions contribute significantly to nitrogen inputs in aquatic and terrestrial ecosystems. Dry deposition of atmospheric ammonia may cause fundamental changes in the biological activity of an ecosystem (i.e. eutrophication). Exact concentrations of atmospheric ammonia have been difficult to quantify due to errors resulting from cross-contamination of samples and reproducibility problems. Annular denuder systems (ADS) coupled with relaxed eddy accumulation (REA) instrumentation were deployed during field experiments in Tampa, Florida, Tallahassee, Florida, and Princess Anne, Maryland to quantify atmospheric ammonia fluxes. An ion mobility spectrometer (IMS) was collocated with the ADS during several of these excursions to continuously monitor the atmospheric ammonia at two different heights to determine any concentration gradients. The utilization of the IMS system will provide increased accuracy and sensitivity of the measurements as well as the benefit of real-time data. Both methodologies will supply data concerning the magnitude of ammonia deposition in coastal areas to various atmospheric modeling efforts. The primary objectives of this study are to (1) develop an IMS protocol for atmospheric ammonia sampling; (2) utilize ADS and IMS methodologies in sampling excursions in coastal locations; (3) compare the resulting data sets from both techniques; and (4) employ the results in the development of atmospheric deposition models.

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