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Highlights

April 2011

Past Highlights

SCIENCE LEADERSHIP

Participation in National and International Meetings
NATO 33rd International Technical Meeting on Air Quality Modeling and its Applications Organizational work has begun for the 33rd NATO ITM to be held in the Eastern United States in mid-September 2013. Site selection is underway with the assistance of the meeting contractor, MACTEC, Inc. A prospective venue for the consideration of the Steering Committee, chaired by Dr. S.T. Rao, should be known by July 2011.

International Conference on Nitrogen and Global Change
Drs. Jesse Bash, Ellen Cooter and over 350 other scientists, policymakers, industry and non-governmental organization representatives from 50 countries gathered in Edinburgh, Scotland at the ‘Nitrogen and Global Change’ international conference April 10 through 14, 2011. The meeting combined the public release of the European Nitrogen Assessment (ENA) with a three-day scientific meeting. With the completion of the ENA, the Nitro-Europe group will now focus its attention on the International Nitrogen Initiative (INI) and the effects of climate change on air-quality (ECLAIRE). The benefit and need for partners outside of Europe was discussed. Future research initiatives in INI and ECLAIRE will include more global assessments of the impact of the control of Nr pollution on regional pollutants and greenhouse gases, and coupled air-quality and biogeochemical models for more robust assessments of the impact that climate change on air-quality, e.g., how the increased surface temperature will affect the rate of NO, N2O and NH3 production and loss from soils.

Dr. Bash chaired a day-long session on the integration of measurements and models to reduce uncertainties in emissions and fate of atmospheric reactive nitrogen. Drs. Bash and Cooter presented three platform papers summarizing the development and evaluation of the CMAQ bidirectional ammonia pilot and the full integration of the bidirectional algorithms for ammonia into CMAQ, and one poster presentation summarizing EPA field experiments at Duke Forest. This new research option in CMAQ is scheduled for public release September, 2011. Similar research is underway by scientific teams in France, the Netherlands, Canada and Denmark. The EPA approach is unique in the way in which the flux is characterized (compensation point) and implemented in CMAQ, the explicit, dynamic computation of soil and canopy flux, and the explicit inclusion of modeled rather than survey-based farm management behaviors. The later feature more fully supports the model applications dealing with alternative policy analysis, land-use change and climate change.

European Geophysical Union (EGU) General Assembly
The 2011 General Assembly of the European Geosciences Union (EGU2011) was held April 3-8, 2011 in Vienna, Austria. The technical conference brings together scientists from all over the world into one meeting covering multiple disciplines of the Atmosphere, Earth, Planetary, and Space Sciences. EGU2011 was attended by more than 10000 participants from over 90 countries. EGU2011 included approximately 700 technical sessions distributed among 23 scientific programs. The atmospheric sciences program at the conference covered multiple technical sessions for each of the following broad areas: meteorology, boundary layer processes, atmospheric chemistry and aerosols, and interdisciplinary sessions in atmospheric sciences. U.S. EPA was represented by Drs. S.T. Rao, Rohit Mathur, and Jonathan Pleim. EPA’s research on the development of the new generation of online integrated Atmospheric Chemical Transport and Meteorology (Numerical Weather Predication and Climate) modeling was presented at a new session on “Integrated physical and chemical weather modelling with two-way interactions” at the conference and included the following presentations:

The EPA scientists also attended talks in numerous other technical sessions including those on: Air pollution modeling, Vertical and long-range transport of trace gases and aerosols, Megacities: Air quality and climate impacts from local to global scales, Atmospheric composition: variability and trends, Atmospheric monitoring using commercial aircrafts: Platforms of opportunity, Satellite observations of tropospheric composition and pollution, analysis with models and applications, Remote sensing of clouds and aerosols, Gas-phase composition and reactivity, Air-Land Interactions, and Clouds, Aerosols, and Radiation.

The EPA participants also attended an all-day kick-off meeting of the project team for the European Cooperation in the field of Scientific and Technical Research (COST) project titled “European framework for online integrated air quality and meteorology modelling (EuMetChem)”. The EPA scientists are collaborators on this multi-institutional collaborative research involving 40 scientists from 30 organizations from 18 COST member countries and several external experts from USA, Canada, and Russia. Presentations and discussions in this meeting focused on issues related to development and evaluation of new generation of online integrated Atmospheric Chemical Transport (ACT) and Meteorology (Numerical Weather Prediction and Climate) modeling systems and methods and challenges in representing the radiative effects of air pollutants. The Principal Investigators of the EuMetChem project agreed that it would be good to alternate between Europe and USA for the project review meetings, with EPA scientists taking the lead for the meeting in the US.

Also, Drs. Rao and Stefano Galmarini, co-chairs of AQMEII, discussed the scope of upcoming workshop on AQMEII. It was agreed that the Phase 2 activity of AQMEII will focus on the interactions of climate change and air quality using coupled meteorology and chemistry models (e.g., WRF-CMAQ, EuMetChem, WRF-CHEM, etc.). The Phase 2 will be launched at the upcoming EPA/CMAS conference in October 2011 in Chapel Hill, NC.

Participation in the EGU2011 conference provided an opportunity to communicate EPA’s research on the next generation integrated atmospheric modeling system and its applications for air quality and climate issues to the broad international community. Attendance at the EGU2011 also facilitated numerous discussions with European scientists and helped further extend and develop EPA collaboration with our European colleagues on finding sustainable solutions to evolving environmental problem associated with air quality-climate interactions.

International GEOS-Chem Meeting
Dr. Havala Pye delivered a presentation entitled "Secondary organic aerosol from low-volatility and traditional VOC precursors" and a presented a poster entitled "Evaluation of CMAQ NO2 predictions over the US using ground-based and satellite observations" at the International GEOS-Chem meeting May 2-4, 2011 at Harvard University.

RESEARCH HIGHLIGHTS

CSS Research Program: Nanoparticle Research and Collaboration
To improve efficiency and reduce particle emissions from diesel engines, cerium, and other nano-scale substances have been added to diesel fuel in recent years. The use of a cerium fuel-borne catalyst results in emissions of cerium that may be in nanoparticle form or agglomerated with larger particles. Researchers across EPA have been examining the health effects of nano-cerium containing material, and AMAD researchers, including Drs. Garnet Erdakos and Prakash Bhave have been working on determining the size of ambient cerium containing particles which will be important for determining health effects. To date, the cerium technology has been more widely implemented in Europe than in the United States. In order to assess the interaction of cerium with particulate matter, and the concentrations and transport of cerium bound to particulate matter, EPA has begun collaborative research. EPA's research on nano-cerium addresses one of the four problem areas (nanomaterials) and multiple framework areas of the Chemical Safety for Sustainability (CSS) Program of Integrated Transdisciplinary Research (ITR). At the beginning of April, Dr. Havala Pye collaborated with Dr. Bob Willis and others to propose further examination of nano-cerium in ambient air. Current and future research efforts and results were discussed. University of Kentucky researchers are working on emission characterization of nano-cerium by looking at one stage of a nano-MOUDI impactor (micro-orifice uniform deposit impactor). There they observed four types of cerium nano-particles: nano-cerium embedded in calcium-rich shells, discrete nanoparticles, clusters of nanoparticles, as well as cerium nanoparticles within soot. Some clusters appeared to be agglomerates of particles, others looked as though they melted and reformed as larger particles. There was discussion of some results of health impact animal studies. There is lung injury even at low, short-term (repeated) exposures, significantly more than would be expected with “plain diesel” fuel. Dr. Garnet Erdakos is preparing to run the near-road air quality model and expected the runs to be completed by the end of April.

Dr. Pye is considering the possibility of size-resolved particle sampling (and possible plant sampling). She participated in an exploratory conversation facilitated by Dr. Prakash Bhave with Drs. Roy Harrison (University of Birmingham, UK) and Markus Kalberer (University of Cambridge, UK) regarding collaboration on sampling and analysis in the UK for nano-cerium. The nano-cerium diesel additive has been in use at a Newcastle, UK bus station since 2005, where there is a nearby sampling site. As follow-up to the UK call, Dr. Pye prepared information regarding the expected seasonality of ambient nano-cerium levels and forwarded an example of a microscopy report. Dr. Harrison and Dr. Kalberer will follow up with their possible contributions at the end of May. Information gained from the ambient sampling campaign would help validate EPA’s model predictions of nano-cerium concentrations in ambient air. The Step One research description for this project was submitted and presented during the April 20th CSS Nanomaterials conference call. At the Scientist-to-scientist meeting at the end of April, the Step One CSS research descriptions, including the EPA proposal, were grouped into 8 integrated research areas. The Nano in Air proposal was placed into Life Cycle Considerations since it addresses the linkages in the continuum between the production of a chemical, its release, environmental fate, and the resulting exposures and adverse outcomes. In the next few months Dr. Pye and Dr. Kathleen Fahey will use the work of Dr. Bhave and Dr. Erdakos in preparing for the possible UK sampling project.

As part of the UK sampling effort, Dr. Pye is also pursuing a nano-cerium plant and soil sampling study partnership with the collaboration of the EPA plant researchers (Drs. Christian Andersen, Mark Johnson, and Paul Rygiewicz). There was a preliminary discussion of what EPA plant researchers might want to do for this project, and how it might be achieved. Information was provided about the UK monitoring site. The EPA plant researchers may try to couple plant and soil sampling with the ambient measurements and determine how much cerium lands on the surface of the leaves, how much would wash off easily with rain, how much can be found within the leaves itself. Other research may address how much cerium gets into the soil and how deep it goes – what is the mobility of the cerium and how much will/can be taken up by the plant? There have been discussions on how plant samples might be obtained and what kind of samples they would be. There is a range of possibilities: leaves could be mailed back to the plant researchers on ice; and there could be soil cores and leaves of different species of plants and grass. Which samples would be taken depends, in part, on the type of site. The plant researchers will summarize what they might be able to do for this project after they receive more information on the site location.

RESEARCH COLLABORATION ACTIVITIES

Air, Climate and Energy Program

Beta Version of the CMAQ Version 5.0 Model Release - A beta version of the CMAQ Version 5.0 (CMAQv5.0) code was recently made available to the external CMAQ development community, much in advance of the official release in September 2011. The motivation for the beta release is three-fold: (1) It provides an opportunity to the external community to incorporate their scientific and algorithmic contributions to the modeling system so that they are part of the final CMAQv5.0 public release and available to the broad user community in a unified and consistent manner, (2) It provides transparency in the EPA model development activities for the outside community and helps exploit synergy with external research, and (3) through early testing of the system by the external community, it complements in-house testing and evaluation activities, leading to a more robust modeling system.

New developments in the CMAQv5.0 model include a redesign of the aerosol module and other structural improvements to facilitate easier updates and modifications by our scientists, our partners within the agency, and external collaborators. Many improvements were made to the science in aerosols, gas-phase chemistry, photolysis, lightning NOx emissions, and chemical transport processes. The new version has already been acquired by outside collaborators, both domestic and international, who are adding new capabilities to the model for the official release in September. In addition, in-house evaluation of the beta model may identify areas for further improvement, some of which will be added for the September release.

The continuing improvement of CMAQ with its periodic new releases helps our partners with their evolving needs for modeling tools to characterize pollution in the ambient atmosphere (i.e. OAR) as well as atmospheric deposition of pollutants to water and terrestrial surfaces (i.e. OW). The CMAQ development and evaluation effort is a key component of the modeling and decision support tools topical area of the Air, Climate, and Energy (ACE) program.

Long-term Deposition Estimates for Critical Load -In previous work with CAMD, Donna Schwede and collaborators found that substituting the hour-of-year average deposition velocity for missing values within the data record provided good estimates of annual deposition flux (Bowker et al, in press). Based on these findings, CAMD is now interested in examining the pairing of CMAQ average deposition velocities with the long term record of concentrations from CASTNET to produce maps of deposition for the US. CMAQ deposition estimates are not currently available for this extended period, but historic deposition estimates are needed as input to biogeochemical models such as MAGIC for use in critical loads analyses. Ms Schwede is collaborating with George Bowker, Gary Lear, and Jason Lynch on creating average deposition velocity estimates from archived CMAQ model results.

Chemical Safety for Sustainability Program

Regional-Scale Modeling to address Chemical Safety for Sustainability - A Step One research description was developed for the Chemical Safety for Sustainability (CSS) research program entitled “Regional multi-media modeling to support the development of multiple-objective, sustainability-driven solutions for agricultural chemicals.” This research will provide sound science information from which to develop sustainable, multi-objective solutions for current and new classes of agricultural chemicals, including pesticides, herbicides, hormones and pharmaceuticals. The focus here is on current or new chemicals that are particularly mobile in one or more media, that are relatively long-lived in their original form, or which transform into daughter or even secondary daughter products that pose a threat to human or ecosystems health and service sustainability, thus making them of interest over larger (>10km) spatial scales. This focus will support the relation of chemical loadings to concentrations in environmental media in remote locations leading to improved characterization of bioavailability It would also facilitate source attribution of releases of such chemicals of interest. Successful progress in this research area will require integration across the CSS Program, as well as collaboration with the Sustainable and Healthy Communities (SHC) and Safe and Sustainable Waters (SSW) research programs.

Agricultural Chemical and Nanoparticle Programs - Dr. Jon Pleim participated in the scientist-to-scientist meetings for the CCS ITR programs on April 26-27 for the Chemical Safety for Sustainability (CSS) ITR program. He presented Ellen Cooter’s research description on multimedia modeling for agricultural chemicals for the Systems Models framework area. Dr. Havala Pye presented the nanoparticles in air description for the nanomaterial problem area

Safe and Sustainable Water Resources Program

Science questions and metrics for Safe and Sustainable Waters – Drs.Ellen Cooter and Robin Dennis provided information regarding outputs and metrics to the Safe and Sustainable Waters (SSW) research program Problem Statement for Agriculture. Input was provided to science objectives dealing with designing sustainable approaches to biofuel feedstock production, designing sustainable approaches to hydrology management in agriculturally-dominated watersheds and achieving agreement among modelers across various agencies about the best uses and interpretations of various hydrologic and water quality modeling tools being developed for or applied to agricultural systems and landscapes.

Sustainable and Healthy Communities Program

NEXUS Study - EPA scientists participated in the Near-road EXposures to Urban air pollutants Study (NEXUS) team meeting and visited the field experiment monitoring sites in Detroit. The team includes scientists from EPA, along with University of Michigan School of Public Health (UMSPH) collaborators (NCER STAR grantee). At the NEXUS meeting, the team discussed various exposure metrics that will be provided to the University of Michigan over the next year for analysis with their health measurement data on asthma symptoms, respiratory infections and biomarkers of inflammation. The NEXUS project involves a multi-step hybrid modeling process in order to reduce uncertainty and to provide adequate air quality characterization for the epidemiologic analysis. The methods for estimating exposure metrics vary from simple approaches, such as GIS-based indicators of exposures, to more complex approaches, such as dispersion modeling combined with exposure modeling that accounts for residential air exchange rates, infiltration, and activity patterns.

EPA's Atmosheric Modeling and Analysis scientists discussed the results of the first phase of air quality modeling with the NEXUS team. In this first phase of modeling assessment, the dispersion model AERMOD was used to capture spatial gradients of the primary traffic-generated air pollutants PM2.5, EC, NOx and CO. Quantifying the degree of success in capturing the gradients is be a part of the ongoing work. The modeling was based on the 2005 NEI/SMOKE emissions inventory processing, emission factor tables from MOVES, traffic network and activity data from SEMCOG, and 2005 meteorology from NWS. Model post-processing and analysis are still in progress.

The next step is to set up a refined modeling analysis. EPA scientists are currently working on verifying the locations of roadways for the link-based emissions modeling. UMSPH collaborators will provide the street address and GPS coordinates for the NEXUS study as well as the list of schools and their locations. The mobile sources portion of the modeling assessment will be based on the AERLINE dispersion model. Evaluation of AERLINE will use the data from the I-96 sites, because of the combination of data available from the intensives and the longer period of measurements. The refined analysis will utilize the results from the screening analysis to refine the source inventory for the 2010/2011 NEXUS simulation, and the results are expected in September 2011.

EPA's Atmospheric Modeling and Analysis scientists also met with EPA researchers from Ann Arbor, MI. EPA scientists discussed research projects, developing new modeling approaches to addressing the air quality impacts of roadways and shared their expertise related to the emission modeling system MOVES and how MOVES can be used to support exposure and health study such as NEXUS.

Extramural Collaborations

Potential International Collaboration on Agriculture and N2O - Challenges associated with the simulation of agricultural soil and crop influences on the flux of nitrous oxide (N2O), a potent and long-lived GHG, was an important topic at the Nitrogen 2011 meeting held in Edinburgh, Scotland during April. Dr. Benoit Gabrielle of the Agronomy, Forestry, Water and Environmental Science and Technology Department at AgroParisTech presented evaluations of field studies to quantify N2O emissions from agricultural fields in France and noted the agricultural models they were using were not sufficient. Under a collaborative research project led by EPA scientists, Dr. Ellen Cooter is tasked to perform similar work, i.e., estimate N2O emissions using an agricultural management model to generate input to CMAQ for biofuel crop production scenario evaluation. A 3-year study to estimate N2O emissions from switchgrass is underway this summer in North Carolina which will contribute to emissions model development and evaluation. Dr. Cooter is beginning to explore the possibility of a field data exchange and an agricultural N2O emissions model intercomparison study with Dr. Gabrielle. As a first step, a description of the U.S. field study will be shared with Dr. Gabrielle to gage level of interest and to determine if they have a similar field study whose results they would be willing to provide to the EPA.

Albemarle-Pamlico National Estuary Program (APNEP) – Dr. Robin Dennis attended the quarterly Science and Technical Advisory Committee (STAC) meeting April 27th in Greenville, NC. A North Carolina (NC) Division of Water Quality representative presented information about proposed new, more stringent water quality standards for NC and emphasized the strong opposition by industry and the current NC legislature to any increase in stringency of water quality standards, especially for drinking water. Coincidentally, the EPA is encouraging the states to adopt numeric standards, especially for nutrients. Dr. Dennis, as a member of STAC, was asked to write a section of the APNEP assessment on atmospheric deposition and ozone exposure. The purpose of the assessment is to provide a sense of the trends in selected metrics and to compare and contrast the current condition of the ecosystems in the APNEP region to conditions that existed in the late 1980’s and early 1990’s. The assessments will become part of the Comprehensive Conversation Management Plan. They are to be modeled after the high level assessment of environmental condition, The State of the Nation’s Ecosystems 2008, produced by the H. John Heinz III Center for Science, Economics and the Environment. Robin is analyzing trends in wet deposition of nitrate and ammonia based on National Atmospheric Deposition Program (NADP) National Trends Network (NTN) data. Dr. Dennis is also examining trends in cumulative ozone exposure across the region, using the W126 metric that is consistent with the EPA secondary standard analyses. Dr. Kristen Foley of EPA and Wayne Cornelius, a statistician at the NC Department of Environment and Natural Resources (NC DENR), are assisting in the analysis.

Public Outreach for Air Quality Modeling - During April, Dr. Tanya Otte worked with Drs. Sergey Napelenok and Rob Pinder to create a public outreach mechanism for air quality modeling issues. The team decided to pursue periodic entries into the EPA’s public blog, Greenversations, under the title “Modeling Matters”. The team’s blog pieces are geared toward educating the general public of the value of our in-house research and how it may affect their lives. Dr. Otte wrote two initial blog postings, which appeared 4 May (during Air Quality Awareness Week) and 11 May. Moving forward, the team aims to contribute to Greenversations approximately once per month.

PUBLICATION ACTIVITY

In Process

Allen, D.J., K. Pickering, R.W. Pinder, K.W. Appel, and B.H. Henderson. Impact of lightning-NO on eastern United States photochemistry during the summers of 2004 and 2006 as determined using the CMAQ model. Submitted to internal review

Appel, K.W., K.M. Foley, J.O. Bash, R.W. Pinder, R.L. Dennis, D.J. Allen and K. Pickering, A multi-resolution assessment of the Community Multiscale Air Quality (CMAQ) model v4.7 wet deposition estimates for 2002-2006, was accepted for publication in Geoscientific Model Development.

Cooter, E. , D. Schwede, R. Dennis, A. Rea, A. Neal, and R. Bruins, The Role of the Atmosphere in the Provision of Ecosystem Services, in preparation.

Crooks, J.L. and V. Isakov, A Wavelet-Based Approach to Blending Multiple Types of Spatio-Temporal Data: Combining Observations with Deterministic Computer Models to Resolve the Intra-Urban Air Pollution Field, prepared for publication in the Journal of Agricultural, Biological, and Environmental Statistics.

Crooks, J. L. and H. A. Ozkaynak. Simultaneous Statistical Bias Correction of Multiple PM2.5 Species from a Regional Photochemical Grid Model. Environmetrics, John Wiley & Sons, Ltd., Indianapolis, IN, in review.

Garcia, V., V. Isakov, and T. H. Watkins. Advances in Modeling Exposure to Support Environmental Health Studies. Environmental Scientist. Institution of Environmental Sciences, London, UK. In review.

Godowitch. J.M., R.C. Gilliam and S.T. Rao. Diagnostic Evaluation of Ozone Production and Horizontal Transport in a Regional Photochemical Air Quality Modeling System, Atmospheric Environment, accepted for publication.

Herwehe, J. A., T. L. Otte, R. Mathur, and S. T. Rao, Diagnostic analysis of ozone concentrations simulated by two regional-scale air quality models. Submitted to Atmospheric Environment.

Hutzell, W.T., D.J. Luecken, W. Appel, and W.P.L. Carter, Interpreting predictions from the SAPRC07 mechanism based on regional and continental simulations. Submitted to Atmospheric Environment.

Luecken, D.J., W.T. Hutzell, and M. Strum, M. Identification of direct and indirect regional sources of atmospheric formaldehyde and acetaldehyde. In internal review prior to submission to Atmospheric Environment.

Pasch, A. N., C. P. MacDonald, R. C. Gilliam, C. A. Knoderer, and P.T. Roberts. Meteorological characteristics associated with PM2.5 air pollution in Cleveland, Ohio, during the 2009-2010 Cleveland multiple air pollution Study. Atmospheric Environment, ;Elsevier Science Ltd, New York, N.Y. In review.

Valari, M., L. Martinelli, E. Chatignoux, J. L. Crooks, and V. Garcia. Time scale effects in acute association between air-pollution and mortality. Geophysical Research Letters, American Geophysical Union, Washington, D.C. In review.

Yu, S., R. Mathur, J. E. Pleim, G. Pouliot, D.C. Wong, B. K. Eder, K. L. Schere, R.C. Gilliam, and S. T. Rao. Comparative evaluation of the impact of WRF-NMM and WRF-ARW meteorology on CMAQ simulations during the 2006 TexAQS/GoMACCS Study - Part I: Ozone. atmospheric chemistry and physics. Copernicus Publications, Katlenburg-Lindau, Germany. In review.

Published

Appel, K.W., K. Foley, J. Bash, R. Pinder, R. Dennis, D. Allen, K. Pickering, A multi-resolution assessment of the Community Multiscale Air Quality (CMAQ) model v4.7 wet deposition estimates for 2002-2006. Geoscientific Model Development 3:2315-2360, 2010.

Appel, W., R. C. Gilliam, N. Davis, A. Zubrow, and S. Howard. Overview of the Atmospheric Model Evaluation Tool (AMET) v1.1 for evaluating meteorological and air quality models. Envronmental Modelling and Software, 26 (4):434-443, 2011.

Baker, K.R. and K. Foley. A nonlinear regression model estimating single source concentrations of primary and secondarily formed PM2.5. Atmospheric Environment: 3, 2011, doi:10.1016/j.atmosenv.2011.03.074, 2011.

Loughlin, D.H., W.G. Benjey, and C.G. Nolte, ESP v1.0: Methodology for exploring emission impacts of future scenarios in the United States. Geoscientific Model Development, 4: 287-297, 2011.

Mitchell, M., J., G. Lovett, S. Bailey, F. Beall, D. Burns, D. Buso, T. A. Clair, F. Courchesne, L. Duchesne, C. Eimers, I. Fernandez, D. Houle, D. S. Jeffries, G. E. Likens, M. D. Moran, R. Christopher, D. B. Schwede, J. Shanley, K. C. Weathers, and R. Vet. Comparisons of Watershed Sulfur Budgets in Southeast Canada and Northeast US: New Approaches and Implications. Biogeochemistry, 103(1-3):181-207, 2011.

Simon, H., P.V. Bhave, J.L. Swall, N. H. Frank, and W.C. Malm, Determining the spatial and seasonal variability in OM/OC ratios across the US using multiple regression, Atmospheric Chemistry and Physics, 11: 2933-2949, 2011.

 

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