Position Openings
NERL Post-Doctoral Program

This project will involve working with senior air quality modelers in NERL's Atmospheric Modeling Division on the development, testing, and refinement of thermodynamic, chemical, and physical processes for simulation of fine (including nanoparticles) and coarse particles in the atmosphere, including those directly emitted by sources as well as those formed by chemical processes in the atmosphere. These particulate matter simulation processes are tested within the context of three-dimensional air quality models, such as EPA's Community Multiscale Air Quality (CMAQ) model, with ambient measurements of fine particles and their precursors from monitoring networks and special field studies. The CMAQ model is a principal tool used by EPA and the states for air quality management and planning.

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

The Atmospheric Modeling Division (AMD) is responsible for developing and evaluating air quality models for simulating pollutant concentrations on all spatial and temporal scales. These models simulate the complex atmospheric processes affecting the transport, transformation, and deposition of criteria and toxic air pollutants. AMD also conducts research in the application of these models in air quality and exposure assessments including air quality forecasting. A researcher is needed to support model development, evaluation, and application of air quality models with emphasis on the Community Multi-Scale Air Quality (CMAQ) Model. This includes enhancement of atmospheric chemistry processes, meteorological processes, and air quality modeling simulation. Performance evaluations and diagnostic evaluations to assess different aspects of models=s suitability or acceptability would be needed along with characterization of model uncertainties.

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

This project is part of ongoing research in the NERL's Atmospheric Modeling Division to study interactions between future climate and regional air quality. Research of the climate downscaling approaches is needed, which involves Global Climate Model (GCM) predictions and mesoscale meteorological models, such as the Weather Research Forecasting (WRF) model. Evaluation of regional climate predictions under current climate will help in judging downscaling techniques and options, and future scenario simulations with different GCMs and different greenhouse gas scenarios will be studied. Working with AMD scientists, who have completed a first phase study of climate impacts on air quality, these regional climate scenarios will be used to study the interactions between climate and air quality. New developments of the Community Multiscale Air Quality (CMAQ) model that include radiative feedbacks between atmospheric pollutants and climate will be used in this study to additionally capture the impacts of air quality on radiation budgets and regional climate.

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

One of the greatest challenges today is being able to properly use biomarkers of exposure to quantitatively estimate human exposures to non-persistent chemicals. Exposure reconstruction is an approach that is currently being used to estimate human exposures to chemicals using biomarkers of exposure. This approach is commonly used when the exposure scenarios resulting in the measured biomarker concentrations are uncertain.

In support of research needs identified under the Human Health Research Program, this project focuses on using an exposure reconstruction approach to understand the relationship between urinary biomarkers of exposure and real-world human exposures to chemicals. The primary goals are to evaluate and refine an existing physiologically-based pharmacokinetic (PBPK) model and perform exposure reconstruction using available human exposure measurement data (i.e., Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study). The project will involve collaboration with the Ecosystems Research Division (ERD) in USEPA's National Exposure Research Laboratory. The ultimate goal of this research is to assess the feasibility of using the exposure reconstruction approach to estimate human exposures to chemicals using urinary biomarkers of exposure.

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

Exposure assessment is one of four major components in the risk assessment process. A great deal of time and money has recently been spent collecting biomonitoring data (e.g., biomarkers); however, this data cannot be used as a surrogate for determining exposure to environmental chemicals. Exposure reconstruction is one approach that provides a means for utilizing biomonitoring data to estimate external exposure. A key component of this process is physiologically based pharmacokinetic (PBPK) models, which provide a means for integrating exposure routes and defining the relationship of biomarker concentration to target tissue dose. One major obstacle in developing these models is a lack of the necessary xenobiotic metabolism parameters such as metabolite identification, kinetic constants and specific enzyme involvement. The latter of these is critical in accounting for population variability and susceptibility, as well as scenarios involving co-exposures where enzyme induction and/or inhibition can lead to drug-drug interactions. The primary goals of this project are to evaluate the appropriateness (i.e., specificity and sensitivity) of existing biomarker data for conducting exposure reconstruction; generate kinetic and mechanistic data needed to develop and/or enhance PBPK models for relating biomarker data to external exposure; and validate these PBPK models in vivo.

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

In support of research needs identified under the Ecosystem Research Program (ERP) and planned in Long Term Goal 2 (LTG2) of the Safe Products/Safe Pesticides (SP2) implementation plan, this project seeks to develop, evaluate, and assess numerical models for forecasting the response of ecosystems (e.g. wetlands) to multiple stressors (nitrogen, mercury, pesticides, land use change, climate change) in a spatially explicit manner. Science issues to be pursued include: (1) developing algorithms for resolving conflicting spatial/temporal scales in the context of modeling the transfer of contaminants between environmental media, and (2) developing multimedia modeling systems that incorporate feedback between media. Focus will also be applied to the development of software based technologies that facilitate the research and application of integrated multi-media modeling.

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

To support the Ecosystems Research Program (ERP), NERL is cultivating efforts to link its atmospheric modeling research with its terrestrial and waterbody modeling research programs. Mathematical models have been developed for each of the media. There is a critical need to integrate a consistent landcover data base into these modeling systems. This position will act as the intermediary model developer for linking the air models with terrestrial and aquatic models to strengthen the NERL and the Office of Research and Development (ORD) multi-media modeling program and to investigate the feedback mechanisms of the bi-directional cycling of nitrogen between these media.

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

In support of research needs identified under the Safe Products/Safe Pesticides (SP2) research program, this project seeks to develop, evaluate, and assess numerical models for simulating the atmospheric transport and fate of pesticide emissions to sensitive ecosystems. The scales of interest range from ~1-1000 km from the location of pesticide application. Algorithms derived from this research will be integrated and tested in models such as the Community Multiscale Air Quality (CMAQ) modeling system, and will be linked to other multimedia models. This research project is part of a long-term research goal to provide environmental managers with tools to predict multi-stressor effects on ecological resources to assess vulnerability and manage for sustainability.

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

The overall goal of this research project is to establish and to evaluate linkages between ambient air quality and human exposure models in the urban environment. Within NERL, the models of primary interest are the Community Multiscale Air Quality (CMAQ) and Stochastic Human Exposure and Dose Simulation (SHEDS) modeling systems. Other modeling systems, including the AERMOD Air Quality Model and the Hazardous Air Pollutant Exposure Model (HAPEM), are of interest. While linking human exposure and air quality models is the ultimate goal of this project, a specific research need in this area is the development of operational numerical models that can simulate ambient air quality at both urban and regional scales. These models are intended for use in establishing ambient air quality standards and performing regulatory assessments related to the Clean Air Act.

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

In order to understand the interactions of human activities and the production and consumption of ecosystems services, this project will explore approaches for characterizing and modeling the dynamics (e.g., temporal and spatial distribution) of humans in the landscape. Particular emphasis will be placed on quantitative research methods, quantitative analysis, and novel approaches for describing and predicting population dynamics, as it relates to ecosystem functions and services, per the NERL Exposure Framework and the Ecosystems Research Multiyear Plan. This work will support priority EPA environmental modeling and assessment efforts for the EPA Office of Research and Development, Ecological Research Program. Close coordination with a diverse group of environmental scientists and geospatial/statistical analysts is required.

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

The services that are derived from ecosystems are functions of the structure, function, and human uses of those systems. This project will address the need for approaches that integrate remote sensing, landscape characterization, other data sources and spatially distributed models in order to create and map the functions that support services and predict their responses to human activities and other drivers of change. This is a challenging project, integrating multi-media modeling with broad-scale "landscape" models, identifying and focusing on several components of the lithosphere, biosphere, and atmosphere to develop indicators, maps and models of ecosystems services. Particular emphasis will be placed on quantitative research methods, quantitative analysis, and mechanisms of ecosystem functions, per the National Exposure Research Laboratory's "Exposure Framework" and in support of the Ecosystems Research Program Multiyear Plan. This work will support priority EPA environmental modeling and assessment efforts for the EPA Office of Research and Development, Ecological Research Program. Close coordination with a diverse group of environmental scientists and geospatial/statistical analysts is required.

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