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TitleA triple-ratios characterization of nitrogen-containing compounds in atmospheric N samples from Alberta using chemical conversion and thermal decomposition of N2O
AuthorSmirnoff, A; Savard, M M; Vet, R; Simard, M C
SourceAdvances in Stable Isotope Techniques and Applications, ASITA 2014, presentations; 2014 p. 1-17
Year2014
Alt SeriesEarth Sciences Sector, Contribution Series 20150123
MeetingASITA (Advances in Stable Isotope Techniques and Applications) 2014 Conference; Davis, CA; US; June 15 - 18, 2014
Documentbook
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceAlberta
NTS82I/01; 83H/11; 83H/12
AreaFort Saskatchewan; Edmonton; Vauxhall
Lat/Long WENS-112.5000 -112.0000 50.2500 50.0000
Lat/Long WENS-114.0000 -113.0000 53.7500 52.5000
Subjectsgeochemistry; nitrogen; isotopic studies; oxygen isotopes
ProgramCoal & Oil Resources Environmental Sustainability, Environmental Geoscience
LinksOnline - En ligne (PDF, 2.24 MB)
AbstractTo better understand the sources and fate of atmospheric N species, it is helpful to characterize the isotopic ratios (d15N, d17O, d18O) in several atmospheric forms and species (precipitation, gases, particles). To achieve this goal, we first chemically converted NO3- and NH4+ collected on filters and absorbents into NO2- and then into N2O. Subsequently, the resulting gas was decomposed into N2 and O2 and analyzed with an isotope ratio mass spectrometer using a pre-concentration system equipped with a gold reduction furnace ¿ the method we previously described (Smirnoff et al., 2012). However, to be able to analyze low-concentration atmospheric samples, we had to modify the existing protocols for sample preparation and isotope analyses. Using the modified procedures, we were able to decrease of the amount originally required for the analysis of NH4+ and of NO3- by 50 and 70% respectively. Consequently, samples containing as low as 48 nmole of NH4+ or 37 nmole of NO3- were analyzed for their d15N values in ammonium and ammonia, and their d17O, d18O and d15N values in nitrite/nitrate. All the analyses were performed with a single pre-con/gold furnace-IRMS system. This approach allows the spectrum of d15N, d17O and d18O ratios from different atmospheric species including nitrate, nitrite, nitric acid, nitrogen dioxide, nitrous oxide, ammonia and ammonium to be determined. The results for the various samples collected are being integrated and interpreted in the contexts of their respective emission sources, which covered agriculture, gas compressors, urban transportation, and coal-fired power plants. These results will substantially contribute into our understanding of sources and pathways for nitrate, nitrite and ammonium, and their impacts on the terrestrial N cycle.
Summary(Plain Language Summary, not published)
To better understand sources and fate of atmospheric nitrogen contaminants, it is crucial to use a wide suite of environmental indicators. To achieve this goal, we first chemically converted the N species into nitrous oxide. Subsequently, the resulting gas was decomposed into nitrogen and oxygen and analyzed with a new procedure that the GSC team has developed over the years. In this specific research study, in order to be able to analyze low-concentration atmospheric samples, we have modified the existing protocols for sample preparation and analyses. Using the modified procedures, samples with significantly lower concentrations (decrease down to 50%-70% of the originally required) have been analyzed. The results for the various samples collected will be interpreted in the context of their respective sampling sites. These results will substantially help distinguishing the sources and understanding the fate of nitrate, nitrite and ammonium and their impacts on the terrestrial N cycle.
GEOSCAN ID296723