Post-Doctoral Research Program

Measurement and modeling of atmosphere-biosphere exchange of reactive nitrogen species

Project number:APPCD-06-15-2015-02
Brief description of research project:A clear understanding of the fluxes of nitrogen species is critical for a number of programs including regional and national programs to address air pollution. Air emissions of nitrogen contribute to formation of particulate matter and can directly deposit on land and water bodies causing myriad other environmental issues. Air quality models such as CMAQ require inputs on nitrogen fluxes to more accurately generate predictions of ozone and particulate matter (PM) concentrations as well as nitrogen deposition. The post-doctoral candidate will investigate air-vegetation-soil interactions that drive atmosphere-biosphere exchange of reactive nitrogen compounds (e.g., ammonia, nitric acid, nitrous acid, organic nitrates) in natural landscapes. Net canopy-scale fluxes and in-canopy processes will be investigated using a combination of micrometeorological flux measurements and advanced resistance-based and inverses source-sink modeling approaches. The candidate will also work on advanced instruments for nitrogen flux measurements and assist in the development of methods (low-cost time-integrated) to better estimate dry deposition of ammonia. Finally, the candidate would assist with the analysis of data collected during field studies to evaluate flux processes. In addition to improving air quality models, the results of the work performed by the post-doc would contribute to the next required OAQPS reviews of the National Ambient Air Quality Standards (NAAQS) for nitrogen oxides and sulfur oxides, particularly for the secondary standard related to ecological impacts.
Geographical location of position:Research Triangle Park, NC
High priority research areas:The selected candidate would directly support ACE task 105 which is focused on providing information on fluxes of ozone, and speciated nitrogen and sulfur compounds. The work directly supports EPA Goal 1 of the Agency’s Strategic Plan entitled Addressing Climate Change and Improving Air Quality. The work will specifically support the applied research under this goal to: Conduct integrated science assessments of criteria air pollutants and provide new data and approaches for improving these assessments and Develop approaches to assess multi-pollutant exposures and the resulting human and ecological effects of air pollutant mixtures” As stated earlier, the work supports the NAAQS secondary NOx/SOx standard and development of flux algorithms for regional chemical transport models.
Scientific project area:Atmosphere-biosphere exchange of reactive nitrogen species
Educational requirements:PhD in Atmospheric Science, Ecology, Physics, Engineering or related field.
Specialized training and/or experience preferred:Micrometeorological flux measurement methods Atmospheric measurements of reactive nitrogen compounds Modeling of air-surface exchange processes
Projected duration of appointment:3 years
Paid relocation to EPA work location:Yes
Application Period Open Date:Jun 16, 2015
Application Period Close Date:Jul 20, 2015
Scientific contact/Principal Investigator(s)*: John Walker,, 919-541-2288

*This person/persons may be contacted for additional scientific information about this project. This person is not authorized to accept applications, make job offers, set salaries, establish start dates or discuss benefits. See general announcement for details on how to apply.