Constraining ammonia emissions and PM2.5 control efficiencies with a new combination of satellite data, surface observations and adjoint modeling techniquesEPA Grant Number: RD834559
Title: Constraining ammonia emissions and PM2.5 control efficiencies with a new combination of satellite data, surface observations and adjoint modeling techniques
Investigators: Henze, Daven K
Institution: University of Colorado at Boulder
EPA Project Officer: Chung, Serena
Project Period: May 1, 2010 through April 30, 2013 (Extended to April 30, 2014)
Project Amount: $249,942
RFA: Novel Approaches to Improving Air Pollution Emissions Information (2009) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
The project goal is to reduce existing uncertainties in current estimates of NH3 emissions in order to better characterize and control distributions of fine particulate matter (PM2.5) and reactive nitrogen.
- Quantify the magnitude and variability, both geographical and seasonal, of U.S. NH3 emissions at a high spatial resolution.
- Provide detailed estimates of PM2.5 control efficiencies and how they will evolve owing to regulations that alter key balances among inorganic particulate species.
The overall approach is to constrain NH3 emissions using new remote sensing observations (TES NH3 retrievals), existing speciated surface observations (IMPROVE, NADP/NTN), and the GEOS-Chem adjoint modeling tools recently developed under a previous EPA-STAR award (R832158). Capabilities and limitations for constraining specific NH3 sources and variability with this data at a high resolution will first be assessed via inverse modeling tests using "pseudo" observations (generated by the model). The inverse model will then be applied over North America using real observations from several recent years. The resulting constraints on NH3 inventories will be evaluated through cross validation with independent data sets and qualified with calculation of uncertainty reductions. Lastly, the impacts of constraining NH3 emissions on control strategies will be determined through novel application of the adjoint model as a sensitivity tool, pinpointing nonattainment to influences from specific emissions locations, sectors, and sources.
Benefits of accomplishing these goals will be to further our overall knowledge of the environmental impacts of NH3 emissions by affording better estimates of incidents of excessively harmful PM2.5 levels using air quality models as well as reducing uncertainty in quantifying the sources and fate of ecologically disruptive levels of reactive nitrogen. NH3 inventory improvements will also enhance calculated emission control efficiencies by more precisely accounting for the response of PM2.5 concentrations to existing or proposed mitigation strategies, thereby targeting emissions controls that minimize risk and cost while maximizing societal benefits.