Nitrogen Deposition onto Aqueous Media: Quantative Diagnostics, Laboratory Measurements, and Model DevelopmentEPA Grant Number: R823333
Title: Nitrogen Deposition onto Aqueous Media: Quantative Diagnostics, Laboratory Measurements, and Model Development
Investigators: Miller, John Houston
Institution: George Washington University
EPA Project Officer: Hiscock, Michael
Project Period: September 15, 1995 through September 14, 1998
Project Amount: $182,227
RFA: Exploratory Research - Chemistry and Physics of Water (1995) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Engineering and Environmental Chemistry
The deposition of nitrogen oxides from the atmosphere is expected to dramatically increase over the next 50 years and will have a profound effect on global tropospheric chemistry. In addition to acidification of terrestrial and marine ecosystems, this process is expected to lead to an increase in the quantity of tropospheric ozone and a decrease in the consumption rate of methane in forest soils. Unfortunately, there is little fundamental data available for the rate of the deposition of individual oxidized nitrogen species or adequate models to account for the chemical interconversion of these species at or near absorbate surfaces. This lack of information has prompted further investigation into the relative contributions of wet versus dry deposition. A clearer understanding of the fundamental processes involved in dry deposition will allow for more accurate determination of atmospheric deposition and prove vital to environmental policy decisions.
With USEPA funds we are conducting a detailed study of nitrogen deposition which involves the development of laser-based diagnostics for the individual NOx species and laboratory measurements of their rates of dry deposition. A model is being developed to account for the data observed in these experiments which will include the interaction of mixing, diffusion, and chemistry during the deposition process.
It is anticipated that the models developed to explain our laboratory results will provide useful estimation tools for nitrogen deposition in the natural environment and thus will provide valuable and necessary input for the development of global climate models.