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Characterization of organic nitrogen in aerosols at a forest site in the southern Appalachian Mountains
Citation:
Chen, X., M. Xie, M. Hays, E. Edgerton, D. Schwede, AND Johnt Walker. Characterization of organic nitrogen in aerosols at a forest site in the southern Appalachian Mountains. IAC2018, St. Louis, Missouri, September 02 - 07, 2018.
Impact/Purpose:
Nitrogen deposition budgets used in ecosystem exposure and critical loads assessments are developed using chemical transport models and national monitoring data, which do not fully incorporate the organic fraction of nitrogen deposition. Because this fraction may be significant, total deposition budgets remain incomplete. This work quantifies the organic fraction of nitrogen in particulate matter in a montane forest ecosystem in the southeastern U.S., and specifically investigates the contributions of organic nitrogen associated with biomass burning (nitro-aromatics) and secondary organic aerosol (nitrooxy-organosulfates). Results from this study improve current understanding the importance of “missing” forms of nitrogen and potential limitations of deposition budgets used to support the secondary NAAQS for NOx/SOx/PM.
Description:
There is extensive evidence showing that boreal and temperate forests are affected by anthropogenic activities, both industrial and agricultural. Such activity results in unprecedented quantities of reactive nitrogen (N) being released into the atmosphere, subsequently altering global nitrogen and carbon (C) biogeochemical cycles. On a global basis, organic N may contribute approximately 25 percent of the total N deposition. Although ubiquitous, widespread routine monitoring of organic N in the atmosphere is inhibited due to difficulties in sampling and inability to fully speciate the wide range of constituents that make up this large pool of atmospheric N. This study investigates the composition of organic particulate matter in a remote montane forest in the southeastern U.S., focusing on the role of organic N in sulfur-containing SOA and aerosols associated with biomass burning.