Source Apportionment of Particulate Matter

FY 2004 Science to Achieve Results (STAR) Program
National Center for Environmental Research

Opening Date: December 2, 2003
Closing Date: March 31, 2004

Technical Contact: Darrell Winner, 202-343-9748, email:
Eligibility Contact: Tom Barnwell, 202-343-9862,

Summary of Program Requirements
Specific Areas of Interest
Standard Instructions for Submitting an Application
Sorting Code

View research awarded under previous solicitations


Program Title: Source Apportionment of Particulate Matter

Synopsis of Program:
The U.S. Environmental Protection Agency (EPA), as part of its Science to Achieve Results (STAR) program, seeks applications for innovative methods to quantify source-receptor relationships that explore current and future relative source contributions of particulate matter for various regions of the US.

Contact Person:
Darrell Winner, 202-343-9748; email:

Applicable Catalog of Federal Domestic Assistance (CFDA) Number(s): 66.509

Eligibility Information:
Academic and not-for-profit institutions located in the U.S., and state, tribal, or local governments are eligible to apply for assistance under this program.

Award Information:
Anticipated Type of Award: Grant
Estimated Number of Awards: Approximately 6-7
Anticipated Funding Amount: Approximately $3 million
Potential Funding per Award per Year: Up to $150,000 per year for up to 3 years
Limitations: Requests over $450,000, including direct and indirect costs, will not be considered

Sorting Code(s):
The sorting code for applications submitted in response to this solicitation is 2004-STAR-F1
Deadline/Target Dates:
Letter of Intent Due Date(s): None
Application Proposal Due Date(s): March 31, 2004


The U.S. Environmental Protection Agency (EPA), Office of Research and Development (ORD), announces an extramural funding competition supporting research to improve source apportionment techniques that determine the origin of fine and coarse atmospheric particulate matter (PM). The goals are to determine the sources contributing to measured concentrations and compositions of PM in ambient air, understand the regional variations in the importance of sources, and use results from these apportionment studies to examine the effectiveness of potential control strategies.


Air pollution is a widespread problem in the United States, with over 130 million individuals exposed to levels of air pollution that exceed one or more health-based ambient standards. One of the major air pollutants of concern, particulate matter (PM), represents a broad class of chemically and physically diverse substances. PM can be described by size, formation mechanism, origin, and chemical composition. The concentration of PM in the air varies across space and time, and is dependent on the source of PM, atmospheric transformations, and meteorological conditions.

Fine and coarse particles are distinct in terms of their emission sources, formation processes, chemical composition, atmospheric residence times, transport distances, and other parameters. For purposes of this RFA, fine particles are defined as particles smaller than 2.5 micrometers in diameter and coarse particles are particles between 10 and 2.5 micrometers in diameter. Fine particles are directly emitted from combustion sources and are also formed secondarily from gaseous precursors such as sulfur dioxide, nitrogen oxides, or organic compounds. Fine particles are generally composed of sulfate, nitrate, organic and elemental carbon, chloride and ammonium compounds, and other compounds. Semi-volatile chemical components of fine particles can partition between the gas- and particle- phase making their measurement difficult by customary filter-based methods. Coarse particles are composed largely from crustal materials that contain calcium, aluminum, silicon, magnesium and iron, although some bioorganic materials, such as pollen and spores, are also found in coarse particle fractions. Sources of coarse particles include road dust, fly ash, and sea salt and are often associated with the mechanical processing and grinding of minerals. Fine particles can remain in the atmosphere for days to weeks and can be transported through the atmosphere over hundreds to thousands of kilometers, whereas the atmospheric deposition of most coarse particles typically occurs within minutes to hours and within tens of kilometers from the emission source.

Fine particles (PM2.5) have been linked to a range of serious respiratory and cardiovascular health problems. The key effects associated with exposure to ambient particulate matter include premature mortality, aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions and emergency room visits, school absences, work-loss days, and restricted activity days), aggravated asthma, acute respiratory symptoms, chronic bronchitis, decreased lung function, and increased risk of myocardial infarction. Recent estimates indicate that exposures to PM2.5 may result in tens of thousands of excess deaths per year, and many more cases of illness among the US population. Due to the complex nature of PM2.5, there are many scientific issues that require further inquiry to support the future efforts of air quality managers who are responsible for designing cost-effective implementation strategies to reduce exposure to harmful levels of PM2.5 across the country. EPA has several emission control plans, such as the NOx SIP Call, that will be implemented over the next several years. In addition, EPA is considering options (i.e., Clear Skies Legislation or the PM Transport Rule) to address regional transport of PM2.5. Because these regulatory approaches are designed to address regional PM2.5 concentrations, the situation in some localities may require additional reductions to meet the National Ambient Air Quality Standards (NAAQS) for PM. Understanding the sources and their contributions to local ambient PM concentrations will be critical to achieving the NAAQS in these cases. Thus, the focus of this RFA is to develop the approaches that will be needed to identify the emission sources of PM2.5 and precursors, for both current sources and for sources that are likely to be significant in the coming decade, at a level of specificity sufficient to develop and evaluate emission control programs.

The overall body of evidence associating coarse particles (PM10-2.5)) with adverse health effects is more limited and less consistent than the evidence for PM2.5 associations, especially with regard to mortality effects. However, scientific evidence is available that links primarily short-term PM10-2.5 concentrations with morbidity and mortality. An important factor surrounding the human health effects due to coarse particles is the lack of available measurement data linking ambient concentrations to sources and exposures. This scarcity has also lead to uncertainties in understanding the relationship between sources and ambient concentrations of coarse particles. The EPA is currently considering potential options for a coarse particle NAAQS. As a result, air quality managers will need tools to develop strategies for addressing non-attainment areas. Given the uncertainty about the sources and composition of the coarse PM fraction, this RFA also includes the need to enhance information about emission sources of coarse PM and precursors to elucidate source-receptor relationships.

The need for research on source apportionment techniques and associated inputs requested through this RFA has been identified in reports produced by the National Research Council (NRC) and NARSTO. Further information about the NRC recommendations on PM research priorities can be obtained at and NARSTO's Strategic Execution Plan, Part 4: Science Plan for Suspended Particulate Matter, February 2001 ( provides further information to potential applicants on research needs.


EPA seeks innovative methods to quantify source-receptor relationships that explore current and future relative source contributions for various regions of the US. EPA is looking for methods that are useable in multiple areas and for various seasons. EPA will not entertain techniques applying to only specific areas or events.

EPA encourages research investigators to address questions such as:

  • What is the relative importance of emission sources, both locally generated and regionally transported, in the formation and daily variation of PM2.5 in different regions of the US?
  • What will be the sources of PM and their relative impacts in areas that may not attain the PM2.5 NAAQS, with emphasis on sources expected in the future?
  • How can source apportionment tools be used to evaluate the effectiveness of emission control programs, particularly in cases where not only the source strength changes, but also the source profiles change?
  • What are the relative source contributions to ambient anthropogenic coarse particle concentrations in different regions of the US, with attention to differences in composition?

The combination of receptor models, chemical transport models (CTM), and emission characterization can be utilized to address one of the specific research questions listed above. In conducting analyses, EPA encourages the use of available data from existing monitoring programs such as the PM Supersites program, the Speciation Trends Network (STN), the IMPROVE network, and the criteria pollutant networks.

Receptor models start with observations of ambient PM at a given location (receptor) and use available information to quantify the sources that contribute to the observed ambient concentrations. Improvements in receptor modeling tools such as incorporating trajectories and chemical transformations into the models (hybrid receptor models) or evaluation and enhancement of current receptor models in conjunction with CTMs could be undertaken in order to answer the specific research questions listed above.

CTMs combine estimated source emission rates with meteorological transport, chemical changes, and deposition rates to estimate concentrations and their temporal variations at different receptors. The combined use of receptor models and CTMs provide a powerful approach to evaluate and refine models, emission inventories and emission reduction strategies. For example, the uncertainty in receptor models could be explored through utilizing synthetic data sets generated by a CTM.

The collection and quantification of source samples may yield significant insight into emission sources not fully captured by current emission inventories. Such profiles may be useful for receptor models, either directly in models such as Chemical Mass Balance or indirectly in the interpretation of inferred source profiles in multivariate receptor models, and for CTMs, by improvement to emission inventories. Improvements over current filter-based sample collection techniques for measuring source aerosol partitioning and equilibria that are comparable to ambient techniques, and the introduction of rapid, repeatable, and accurate analytical technologies for improved physical and chemical measurements of source emissions would be particularly useful. The improved source profiles, where needed, would be incorporated within a broader chemical-based source apportionment proposal.


Interagency Monitoring of Protected Visual Environments (IMPROVE) program

NARSTO's Strategic Execution Plan, Part 4: Science Plan for Suspended Particulate Matter, February 2001 (

NRC's Research Priorities for Airborne Particulate Matter Vol. II

NRC's Research Priorities for Airborne Particulate Matter Vol. III

US EPA Clear Skies Initiative


US EPA PM monitoring network

US EPA PM speciation network

US EPA Supersites


It is anticipated that a total of approximately $3 million will be awarded, depending on the availability of funds. EPA anticipates funding approximately 6-7 grants under this RFA. EPA seeks the most cost-effective proposals that utilize funding of up to $150,000 per year for up to 3 years. Requests with EPA funding amount in excess of $450,000, including direct and indirect costs, will not be considered.
Assume a starting date of no earlier than August 2004 for budgeting purposes.


Institutions of higher education and not-for-profit institutions located in the U.S., and tribal, state and local governments, are eligible to apply. Profit-making firms are not eligible to receive grants from EPA under this program.

National laboratories funded by federal agencies (Federally-funded Research and Development Centers, “FFRDCs”) may not apply. FFRDC employees may cooperate or collaborate with eligible applicants within the limits imposed by applicable legislation and regulations. They may participate in planning, conducting, and analyzing the research directed by the principal investigator, but may not direct projects on behalf of the applicant organization or principal investigator. The principal investigator's institution, organization, or governance may provide funds through its grant from EPA to a FFRDC for research personnel, supplies, equipment, and other expenses directly related to the research. However, salaries for permanent FFRDC employees may not be provided through this mechanism.

Federal agencies may not apply. Federal employees are not eligible to serve in a principal leadership role on a grant, and may not receive salaries or in other ways augment their agency's appropriations through grants made by this program. However, federal employees may interact with grantees so long as their involvement is not essential to achieving the basic goals of the grant. EPA encourages interaction between its own laboratory scientists and grant principal investigators for the sole purpose of exchanging information in research areas of common interest that may add value to their respective research activities. This interaction must be incidental to achieving the goals of the research under a grant. Interaction that is “incidental” does not involve resource commitments.

The principal investigator’s institution may enter into an agreement with a federal agency to purchase or utilize unique supplies or services unavailable in the private sector. Examples are purchase of satellite data, census data tapes, chemical reference standards, analyses, or use of instrumentation or other facilities not available elsewhere. A written justification for federal involvement must be included in the application, along with an assurance from the federal agency involved which commits it to supply the specified service. Potential applicants who are uncertain of their eligibility should contact Tom Barnwell in NCER, phone 202-343-9862,


The Standard Instructions for Submitting a STAR Application including the necessary forms will be found on the NCER web site.


The need for a sorting code to be used in the application and for mailing is described in the Standard Instructions for Submitting a STAR Application. The sorting code for applications submitted in response to this solicitation is 2004-STAR-F1.

The deadline for receipt of the application by NCER is March 31, 2004.


Further information, if needed, may be obtained from the EPA official indicated below.
Darrell Winner, 202-343-9748,