Clean Air Research Multi-Year Plan 

2008-2012 

June 2008

 U.S. Environmental Protection Agency 

Office of Research and Development 

Research Triangle Park, NC 27711 
Administrative Note 

The Office of Research and Development’s (ORD) Multi-Year Plans (MYPs) describe what 

research ORD proposes to accomplish over the next 5-10 years in a variety of areas. The 

MYPs serve three principal purposes: to describe where the research programs are going, to 

present the significant outputs of the research, and to communicate the research plans within 

ORD and with stakeholders and clients. Multi-year planning permits ORD to consider the 

strategic directions of the Agency and how research can evolve to best contribute to the 

Agency’s mission of protecting health and the environment. 

MYPs are intended to be “living documents.” ORD will update MYPs on a regular basis to 

reflect the current state of the science, resource availability, and Agency priorities. This MYP 

was reviewed by ORD’s Science Council in October 2007. 

ii 
Contributors 

Writing Team 

Dan Costa, National Program Director 

Stacey Katz, National Center for Environmental Research (NCER) 

David Kryak, National Exposure Research Laboratory (NERL) 

Douglas McKinney, National Risk Management Research Laboratory (NRMRL) 

Andy Miller, NRMRL 

Gail Robarge, NCER 

Bill Russo, National Health and Environmental Effects Laboratory (NHEERL) 

Laurel Schultz, Office of Research and Development 

Contributors

Barbara Glenn, NCER 

Joe Jarvis, Office of Resources Administration and Management 

Carlos Nunez, NRMRL 

Russell Owen, NHEERL 

Jim Vickery, NERL 

Darrell Winner, NCER 

Reviewers

Allen Basala, Office of Air Quality Planning and Standards (OAQPS) 

Rich Cook, Office of Transportation and Air Quality (OTAQ) 

John Girman, Office of Radiation and Indoor Air (ORIA) 

Beth Hassett-Sipple, OAQPS 

Marion Hoyer, OTAQ 

Scott Jenkins, OAQPS 

Laura Kolb, ORIA 

Phil Lorang, OAQPS 

Bill Lovely, Region 1 

Joann Rice, OAQPS 

David Risley, Office of Atmospheric Programs (OAP) 

Linda Sheldon, NERL 

John Vandenberg, National Center for Environmental Assessment (NCEA) 

Other Research Coordination Team members

Monica Alvarez, Office of Science Policy (OSP) 

Andrea Cherepy, Office of Program Management Operations (OPMO) 

Robert Fegley, OSP 

Doug Grano, OAQPS 

Richard Haeuber, OAP 

Becky Higgins, OPMO 

Bryan Hubbell, OAQPS 

William Johnson, OAQPS 

Carl Mazza, Office of Air and Radiation 

Ken Mitchell, Region 4 

iii 
Michael Morton, Region 6 

Solomon Pollard, Region 4 

Rich Scheffe, OAQPS 

Mohamed Serageldin, OAQPS 

Chon Shoaf, NCEA 

Marybeth Smuts, Region 1 

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Table of Contents 

List of Acronyms and Abbreviations ............................................................................................. vi 

I. INTRODUCTION .................................................................................................................. 1 

A. Program Purpose ................................................................................................................. 1 

B. Program Design .................................................................................................................. 3 

1. Major Policy Challenges and Science Needs.................................................................. 5 

2. External Program Reviews ........................................................................................... 11 

3. ORD Laboratories and Centers ..................................................................................... 13 

4. Client-Partners for Air Research ................................................................................... 14 

5. ORD Partners in Research ............................................................................................ 14 

6. Resources ...................................................................................................................... 16 

II. THE CLEAN AIR RESEARCH MULTI-YEAR PLAN ..................................................... 16 

A. Changes from the Previous MYP ..................................................................................... 16 

B. Long-Term Goals .............................................................................................................. 17 

C. LTGs in Relation to Air Program Needs, Priority Science Questions and APGs ............ 17 

D. Linking Clean Air Research with other ORD Programs .................................................. 33 

E. Performance Assessment Rating Tool Long-Term Goals and Measures ......................... 35 

III. CONCLUSIONS............................................................................................................... 37 

Appendix A: Recent Program Accomplishments ......................................................................... 39 

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List of Acronyms and Abbreviations 

APG – Annual Performance Goal 

APM – Annual Performance Measure 

BOSC – Board of Scientific Counselors 

CAA – Clean Air Act 

CAIR – Clean Air Interstate Rule 

CAMR– Clean Air Mercury Rule 

CAVR– Clean Air Visibility Rule 

CENR – Committee on Environment and Natural Resources 

CMAQ – Community Multiscale Air Quality 

CRC – Coordinating Research Council 

DOE – Department of Energy 

EPRI – Electric Power Research Institute 

FACA – Federal Advisory Committee Act 

HAP – hazardous air pollutant 

HEI – Health Effects Institute 

HHRA – Human Health Risk Assessment 

HHRP – Human Health Research Program 

IRIS – Integrated Risk Information System 

L/C – Laboratory/Center 

LTG – Long-term Goal 

MACT – Maximum Achievable Control Technology 

MYP – Multi-year Plan 

NAAQS – National Ambient Air Quality Standard 

NAS – National Academy of Sciences 

NATA – National Air Toxics Assessment 

NCEA – National Center for Environmental Assessment 

NCER – National Center for Environmental Research 

NHLBI – National Heart, Lung, and Blood Institute 

NIEHS – National Institute of Environmental Health Sciences 

NOx – nitrogen oxides 

NRC – National Research Council 

OPA – Office of Atmospheric Programs 

OAQPS – Office of Air Quality Planning and Standards 

OAR – Office of Air and Radiation 

OMB – Office of Management and Budget 

ORD – Office of Research and Development 

OTAQ – Office of Transportation and Air Quality 

PART – Performance Assessment Rating Tool 

PM – particulate matter 

RCT – Research Coordination Team 

RFA – Request for Application 

RPOs – Regional Planning Organizations 

SERDP – Strategic Environmental Research and Development 

SIP – State Implementation Plan 

SOx – sulfur oxides 

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I. INTRODUCTION 

A. Program Purpose 

Air pollution continues to have adverse impacts on the human and environmental health of the 

United States, despite clear evidence that overall air quality has improved.1

 The EPA Strategic 

Plan 2006-2011 (Strategic Plan) identifies Clean Air and Global Climate Change (Goal 1) as a 

primary goal for environmental protection with its first objective being Healthier Outdoor Air, 

and its second objective, Healthier Indoor Air.2 EPA’s Strategic Plan Goal 1 also establishes an 

objective to provide and apply sound science to support the goal of clean air by conducting 

leading-edge research to support regulatory decisionmaking. This research provides the scientific 

foundation to develop regulations and advanced tools and models to implement air quality 

standards and controls by the States, EPA Regions, and tribes. At the same time, the research 

program strives to develop better ways to track progress in achieving health and environmental 

improvements under this goal. The Clean Air Research program targets this first objective by 

providing the science needed to review, attain, and maintain ambient air quality standards 

required to protect public health. This research, together with the rest of the Clean Air Research 

program, has the added benefit of addressing risk reduction from a number of toxic air 

pollutants, and increases in the number of Americans experiencing healthier indoor air in homes, 

schools, and office buildings. Although the Clean Air Research program considers within its 

overall goal the reduction of air pollution impacts on ecosystems and visibility, research specific 

to the protection of public health remains the top priority of the Office of Research and 

Development’s (ORD’s) clients. 

In 2007, the White House Office of Management and Budget (OMB) found that reductions in 

hospitalizations and emergency room visits, lost work and school days, and premature deaths 

account for the greatest expected benefits of air pollution regulation. Between 1996 and 2006, 

OMB attributed an annual savings of $63 to $430 billion to the development and implementation 

of air pollution regulations–most notably from control of particulate matter (PM).3

 The benefits 

of air pollution regulation accounted for ~94% of estimated benefits from all EPA regulations 

and ~63 to 88% of estimated benefits across all federal agencies, while costing an estimated $25 

to $28 billion to implement over this same period. 

ORD has developed multi-year plans (MYPs) in a number of program areas to describe the 

research ORD proposes to accomplish over the next several years. The MYP is intended to 

provide a vision of the research program and the programmatic rationale for its intended 

directions. In addition, the MYP provides an up-to-date, structured listing and description of the 

significant expected outputs from its research, which serves to communicate across ORD and 

 

1

 These data are summarized in the Air Quality Criteria Documents for PM (10/29/04 - 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87903) and Ozone and Related Photochemical Air Pollutants (01/31/05 - 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=114523). Risks from Hazardous Air Pollutants possess even greater 

uncertainty (http://www.epa.gov/ttn/atw/nata/natsa4.html). Additional information on trends in air quality and emissions can be 

found at the Office of Air and Radiation site: http://www.epa.gov/air/airtrends. 2

 EPA Strategic Plan 2006-2011 (Goal 1: Clean Air and Global Change; Objectives 1.1, 1.2, 1.6; p. 11) –

http://www.epa.gov/ocfo/plan/2006/goal_1.pdf. 3

 Draft 2007 Report to Congress on the Costs and Benefits of Federal Regulations – Tables 1.1 and 1.2; pp. 7-8; - 

http://www.whitehouse.gov/omb/inforeg/2007_cb/2007_draft_cb_report.pdf. 

1 
with stakeholders, clients, and reviewers. Multi-year planning permits ORD to consider the 

strategic directions of the EPA and how research can evolve to best meet the EPA’s mission of 

protecting public health and the environment. 

This MYP supports the goal of Clean Air by defining the research needed to answer key 

questions regarding the development and implementation of National Ambient Air Quality 

Standards (NAAQS)–primarily targeting PM and ozone as high-risk pollutants. In addition, it 

also supports, although secondarily, the goals of managing hazardous air pollutants (HAPs)This 

MYP includes a major shift in the Clean Air Research program by combining several program 

areas that previously had targeted air pollutants individually (e.g., PM, ozone, HAPs)Although it 

is essential to provide support for the various NAAQS pollutants that continue to be regulated 

individually, a multipollutant research program better reflects the complexity of real-world air 

pollution problems and parallels the evolving scientific and regulatory context. The Clean Air 

Research program uses the science-based framework, shown in Figure 1, developed by the 

National Academy of Sciences’ (NAS’s) National Research Council (NRC) in 1998 and 

modified by the Air Quality Research Subcommittee (AQRS) of the Committee on Environment 

and Natural Resources (CENR) in 2007 to identify those pollutants and sources responsible for 

the greatest health risk. Critical components of this research are used to develop an 

understanding of how pollutants from sources impact ambient concentrations, how these 

concentrations relate to exposures, and, in turn, how exposures relate to health outcomes. This 

information provides the fundamental linkages for evaluating health impacts, ascertaining which 

sources are most egregious in terms of health risk, and in developing effective mitigation 

strategies. 

Figure 1. Paradigm for Federal Research on Particulate Matter4

 

4 From http://www.esrl.noaa.gov/csd/AQRS/reports/pmplan.pdf 

2 
The transition to an air research program emphasizing both “source to health outcomes” and 

multipollutant approaches reflects the recommendations of EPA advisory boards and the 

reorganization of the Office of Air Quality Planning and Standards (OAQPS). The NRC, over 

the period of 1998 to 2004, developed for EPA, under a Congressional directive, a series of 

documents to guide PM and copollutant research. The last report (April 2004) recommends that 

EPA adopt a broader multipollutant research perspective, and increase its efforts to link observed 

heath outcomes with specific components and sources of PM.5

 This approach was endorsed by 

EPA’s Board of Scientific Counselors (BOSC) in 2005.6 Likewise, following the lead of a 

related NRC report entitled “Air Quality Management in the United States,” the Clean Air Act 

Advisory Committee (CAAAC)7, consisting of representatives from EPA, State and local 

agencies, tribes, industry, and environmental and research organizations, also strongly endorsed 

a broad air quality, rather than a pollutant-by-pollutant, approach for more effective air quality 

management. Finally, in keeping with the CAAAC recommendation, OAQPS, which is a main 

client of the ORD Clean Air Research program, has reorganized away from pollutant-specific 

groupings to a more sector-based structure to improve HAPs control and air quality assessment. 

Based on the combination of guidance from external advisory boards and the evolving needs of 

our clients, the focus of the Clean Air Research program was adjusted to support this more 

realistic, yet complex air pollution approach. 

B. Program Design 

In support of the broader EPA and ORD Strategic Plans, this MYP provides a focused strategy 

for Clean Air Research for ORD laboratories and centers and identifies linkages to other relevant 

MYPs such as the Human Health Research program (HHRP) and the Human Health Risk 

Assessment (HHRA) program. It provides a “roadmap” built on the progress that ORD has made 

since 1998 when PM rose to prominence via Presidential and Congressional mandate.8

 The 

roadmap, however, is intended to be sufficiently flexible to facilitate responsiveness to 

unforeseen changes and developments in the complex scientific landscape ahead. 

The development of this roadmap is reflected in the diagram illustrated in Figure 2, which 

outlines the progression of scientific research from the recognition of need to use the new 

information with its impact on human and environmental outcomes. 

The fundamental problem-driven question that drives the Clean Air Research program is “How 

can we reduce health risks associated with exposure to air pollution?” The ability to adequately 

address this overarching question requires that ORD maintain and continue to develop its core 

research capabilities across a diverse range of scientific disciplines, including: cell, animal, and 

human toxicology; epidemiology and biostatistics; human exposure; source emissions 

characterization and analysis; source apportionment; ambient measurements; atmospheric 

chemistry; air quality modeling and forecasting; and technology evaluation and assessment. 

 

5 National Academy of Sciences (NAS) National Research Council (NRC): Research Priorities for Airborne Particulate Matter: 

http://books.nap.edu/catalog.php?record_id=10957. 6

 BOSC Report on the PM-Ozone Program Review: April 2005 - http://www.epa.gov/osp/bosc/pdf/pm0508rpt.pdf. 7 http://www.nap.edu/catalog/10728.html. 8

 “Particulate Matter Research Program: Five Years of Progress” released in February, 2004, which summarized the 

achievements of EPA’s research program in advancing our understanding of both health/exposure and air quality issues through 

early 2003 (http://www.epa.gov/pmresearch/pm_research_accomplishments/). 

3 
Figure 2. Logic Diagram.

EPA Strategic Goal 1: Protect and 

improve the air so it is healthy to 

breathe, and risks to human health 

and the environment are reduced. 

Reduce greenhouse gas intensity by 

enhancing partnerships with 

businesses and other sectors. 

Identify Knowledge Gaps 

and Research Questions

Identify Performance 

Goals for Each Topic

Identify Research 

Develop Themes 

Lab/Center 

Operating 

Plans 

 EPA’s Annual 

Decisions about 

Budgets and 

Resources 

Progress in 

Research 

Activities 

Funded for 

Each Topic 

Research 

Outputs: 

New Research 

Knowledge and 

Applications 

EPA/Client 

Actions 

Research Contributes 

to Changes in 

Knowledge, Skills, and 

Decisions 

RESEARCH IMPACT METRICS: 

BIBLIOMETRIC ANALYSIS, APGS, CLIENT USE

EPA Actions 

Lead to 

Improved Air 

Quality 

Planning and Budgeting 

RESEARCH OUTPUT METRICS: 

PUBLICATIONS, BIBLIOMETRIC ANALYSIS, APMs, APGs 

Research, Application, Action, and Results 

METRICS FOR 

ENVIRONMENTAL 

RESULTS 

INDICATORS OF CONDITION & 

CHANGE IN CONDITION

These fundamental capabilities are leveraged within the Clean Air Research program and ORD 

to maximize project output, science relevance, and resource efficiencies. The goal is to not only 

address research questions of immediate importance to reducing air pollution health risks, but 

provide the foundation to anticipate and solve future environmental problems. 

ORD structures its research agenda to address its clients’ needs and the research priorities 

identified by the science community. As detailed below in the research plan, key long-term 

science goals (LTGs) are established from which critical questions are fashioned to frame the 

research over the next several (~5) years. Researchers work with their Laboratory/Center (L/C) 

representatives to develop annual performance goals (APGs) that collectively achieve the LTGs 

over a period of years. More specific annual performance measures (APMs) collectively provide 

the comprehensive body of research to support a given APG. As such, the APMs are the science 

building blocks that describe the products expected from the relevant scientific research. Thus, to 

reflect the overall program investment and to be effective, this MYP places considerable 

emphasis on the planning and the integration of research. Importantly, however, some latitude 

for novel and creative initiative is built within the program in an effort to link fundamental 

science and breakthroughs with known, pressing air pollution problems. 

The plan and its science are reviewed at several stages along its development. A Research 

Coordination Team (RCT) comprised of senior scientists and managers from each ORD 

Laboratory and Center and multiple representatives from interested client Offices and Regions 

reviews the priority structure and overall framework of the various LTGs and APGs. The RCT 

also reviews the APMs and the descriptors that accompany them to gain insight into the plan and 

its anticipated products. Indeed, the APMs in many cases arise from discussions with members 

4 
of the RCT in the early stages of MYP development. 

To ensure the utility and recognition of delivered products, each APG has a designated ORD lead 

and a client (partner)-advocate who communicate throughout the life of the. This regular 

discourse is designed to ensure progress, the communication of findings, and appropriate 

distribution of the anticipated product to the client/partner office and broader community. 

Finally, the MYP has been reviewed by ORD’s Science Council and an external review panel 

(i.e., BOSC) for scientific soundness. However, it is important to appreciate that the MYP is 

regarded as a “living document” meant to serve as a roadmap with important science milestones, 

while maintaining sufficient fluidity to absorb the newest findings and the ability to evolve from 

there. Naturally, as workforce and fiscal resources are increasingly constrained, the final MYP 

reflects primarily the highest research priorities, with the intent of achieving the most effective 

program possible within ORD’s direct and leveraged resources. As described below, the program 

design and implementation considers major policy challenges, external program reviews, the 

capabilities of the ORD laboratories and centers, partner needs, ORD partner capabilities, and all 

available resources. 

1. Major Policy Challenges and Science Needs 

The Office of Air and Radiation (OAR) is responsible for multiple policy areas regarding the 

“air” environment and, as such, comprises several offices with specific, yet wide-ranging 

functions: OAQPS–ambient air regulation and rule implementation; the Office of Transportation 

and Air Quality (OTAQ)–fuels and mobile sources; the Office of Radiation and Indoor Air 

(ORIA)–indoor environments; the Office of Atmospheric Programs (OAP)–air quality through 

market systems, ecosystem protection, and climate; and the Office of Policy Analysis and 

Review (OPAR)–policy and rule analysis. Facing an array of complex policy decisions that rely 

on the latest and most robust science, OAR is a major user of clean air research. As a result, 

representatives of OAR are members of the RCT and provide invaluable advice to ORD as it 

develops its research agenda. Because the EPA Regions, States, and tribes are critical to rule 

implementation, they themselves frequently have specific and immediate needs (some research, 

some advisory) that ORD is challenged to address. 

With finite resources, priorities or scaled emphases across needs are requisite if adequate and 

timely progress (products) is to be achieved. As already noted, program priorities are established 

within the RCT where partner needs and the appropriate science support can be negotiated 

collectively toward consensus products. Although resources are critical in the final program 

development, prioritization uses broad criteria, such as the likely magnitude of public health 

impact, the narrowing of the greatest uncertainties affecting decision-making, and the 

anticipation of information needed to support future OAR decisions or directions. The goal is to 

achieve a research program structure that best meets these criteria. Because PM and ozone score 

highly among these criteria and are NAAQS pollutants, they remain central to ORD’s Clean Air 

Research program (for both standard setting and implementation) and garner considerable 

attention among other NAAQS and air toxic pollutants. 

5 
The challenges and needs of ORD’s clients/partners in the program offices and as users in the 

field are many and multifaceted, and, therefore, this MYP cannot possibly address every research 

issue identified as a need. Instead, OAR’s highest priority regulatory and policy challenges 

related to air quality that require the most significant research investment are highlighted below. 

Within the challenges and needs expressed below, an attempt was made to reflect the perspective 

of the user including those at the Office, Regional, State, or local levels. 

a. NAAQS Setting and Implementation. The protection of public health (including susceptible 

populations) through the development and attainment of appropriate, protective air quality 

regulations is fundamental to the tasked mission of OAQPS. Clearly, meeting these regulations 

in the most cost-effective and efficient manner is in the best interests of public health, the 

environment, and the economy. There are six NAAQS that undergo repeated, periodic review to 

meet the statutory requirement of the Clean Air Act (CAA), yet the estimated impacts of 

reductions in ambient PM and ozone continue to drive the bulk of the public health benefit. The 

other NAAQS also factor into the overall air pollution burden, but their risks appear less 

substantial because of less exposure risk and/or ambient reductions, with lead recently gaining 

renewed emphasis because of public interest and health impacts at levels not previously 

appreciated. The uncertainties across the NAAQS are similar in magnitude and potential public 

impact, and, as a result, the uncertainties underlying the standard setting process for PM and 

ozone (with their potential impacts) sustains these two pollutants at the highest priority. Between 

these two NAAQS themselves, the risks and benefits associated with PM and its reduction in 

ambient air has retained the highest ORD interest and, hence, emphasis on PM. 

More specific challenges related to the review of the PM and ozone NAAQS that require 

research support include: 

• uncertainties surrounding the PM2.5 standards, 

• uncertainties surrounding the PM10 standard (vis a vis coarse PM), 

• level and form of the ozone and PM standards, 

• uncertainties regarding co-pollutants in PM-associated health effects, 

• the potential for interactions between PM and ozone in health outcomes, 

• definition / characterization of populations that may be susceptible to pollutant effects, 

and 

• potential for an alternative to the mass-based PM standard through identification of 

hazardous components. 

More specific challenges related to NAAQS implementation that require research support 

include: 

• continuing nonattainment problems (post-sulfur/nitrogen controls), 

• uncertainties around predicting impacts of control strategies on air quality, 

• development of improved methods to effectively and rapidly measure pollutants, 

• uncertainties around the input variables for refinement of air quality models, 

• uncertainties around which sources contribute to ambient levels of PM, and 

• development of improved emission inventories. 

Much of the current Clean Air Research program focuses on these challenges. As will be detailed 

below under LTG 1, providing the research that underlies the development and implementation 

6 
of the NAAQS is at the core of the research program. As the program evolves, as described in 

this document, these research activities are being leveraged to expand both the level of 

understanding of these NAAQS and the broader array of air pollutants and their effects alone and 

as mixtures. 

b. Mobile and Stationary Source Air Toxics. The 1990 CAA requires EPA to reduce emissions 

and exposures to 188 specified HAPs (also known as air toxics). Air toxics emissions arise from 

major stationary sources, smaller (area or point sources), on-road (cars and trucks), and non-road 

sources (trains, construction equipment, barges, airplanes, etc.)Through implementation of the 

Maximum Achievable Control Technology (MACT) program, many stationary sources have 

installed available technologies to address risks of the 188 air toxics. The key challenge now 

facing the EPA is to determine if there are unacceptable remaining (“residual”) risks after these 

technologies have been installed. There is need for refined emission inventories of HAP 

emissions to support these residual risk determinations and to better estimate potential 

community exposures. Because air quality monitoring of the HAPS is more limited than with the 

NAAQS, the quality of the National Air Toxics Assessment (NATA) for the various HAPs is 

highly dependent on these inventories to model potential exposures. 

One of the more significant challenges to upgrading the current emission inventory is the 

assessment of those sources emitting pollutants over a wide geographic area rather than from a 

single point source (e.g., a smoke stack). These sources can range from landfills to refinery leaks. 

It will be critical to get a better handle on these emissions and understand the associated public 

exposures to address such risks through residual risk standards or other regulatory designations 

(area source standards). The NATA focus at present is on 177 HAPs thought to be of greatest 

risk (by virtue of estimated exposure or compound toxicity) and on diesel exhaust emissions. The 

hazard and dose-response analyses to support assessment of noncancer and cancer risks from 

exposure to HAP compounds are being developed by the Integrated Risk Information System 

(IRIS) program (in the HHRA program) using published data. Nevertheless, there is significant 

need for information (e.g., mode of action, models) that can be used more broadly to reduce 

uncertainty in risk assessments related to HAPs in the ambient environment. 

Research among the HAPs is targeted in certain areas and otherwise leveraged from the NAAQS 

program. The Health Effects Institute (HEI) provides a significant research base among selected 

HAPs as to their risk as point sources or local “hot-spots.” 9

 Other research utilizes source-based 

approaches to conduct health research (e.g., diesel) or emission assessments (including methods 

development) as described above. As these provide insight into the PM issue, their investigation 

has importance across client information needs. The use of specific HAPs as models that relate to 

PM or its effects is also supported; however, specific study of HAP toxicity or its dose-response 

for IRIS is generally not part of the sponsored program. 

c. Near-Road/Traffic. Emerging information linking human proximity (living, working, or school 

environments) to roadways with a range of adverse health effects has led to growing public 

concern. These concerns have been communicated through OTAQ, ORIA, and OAQPS, as well 

as from the EPA Regions as an area of great uncertainty, despite its priority. In fact, concerns 

over potential health impacts from exposure to emissions near roadways have affected several 

 

9

 HEI publications on air toxics: http://pubs.healtheffects.org/topics.php?topic=1&sort_by=pubdate&order=desc. 

7 
transportation projects across the country, as well as a variety of policy decisions. Among these 

are findings with respect to “conformity” of transportation plans and projects with State 

Implementation Plans (SIPs) for attainment of the NAAQS and local decisions regarding the 

location of schools and other projects (e.g., freight terminals) as required under the National 

Environmental Policy Act (NEPA). These policy decisions are being made even though the 

scientific uncertainties for the linkages to exposure, hazardous agents, and adverse health effects 

vary greatly. 

 

Near-road concerns cross a number of priorities among program clients. Mobile source 

emissions comprise several HAPs (e.g., benzene, aldehydes, butadiene) as well as several 

NAAQS (carbon monoxide, nitrogen dioxide, PM, lead). Most importantly, the emergence of 

traffic as a source signal in the PM arena presents this source category as ideal for study. As 

discussed further below, this source category has been selected as a prototype for multipollutant 

study. 

d. Moving Toward a Multi-pollutant Program to Support Air Quality Management Decisions.

Fundamental to a multi-pollutant approach to air quality management is the recognition of the 

demands on the science to unravel the complex nature of the contributing sources, the 

atmospheric chemistry, the human exposure/environmental deposition, and, of course, the 

associated health and ecosystem impacts. A venture into such a broader based perspective has 

begun with the recent review of the nitrogen oxides (NOx)/sulfur oxides (SOx) NAAQS (2007), 

where the ecological impacts of these pollutants were considered together. With NOx/SOx, the 

common theme of acidity and enhanced nutrients in the environment were used for the combined 

assessment. However, if a multi-pollutant framework is to be more widely embraced for the 

purpose of air quality management (human as well as environmental health), there is a real need 

for research to develop analytic approaches to assess multi-pollutant human and environmental 

health impacts, especially through multimedia pathways, with emphasis on indicators, 

benchmarks, and interaction-based algorithms. To achieve such a goal, the air pollution sciences 

will need unprecedented integration and will demand novel tools for assessment to aid 

interpretation, develop implementation plans, and assess their effectiveness (outcome). Adding 

to these needs as we move ahead in the 21st century, the challenge is heightened by the NAS 

recommendation that future policies for air pollution control be integrated with climate change 

criteria.10 

OAQPS envisions the goal of a multi-pollutant approach to air quality as leading to a more 

effective means of achieving environmental benefits and recently has undergone a reorganization 

to reflect this multi-pollutant and sector-based (source) perspective. The office also has begun to 

evaluate the technical issues associated with multi-pollutant approaches11 In this regard, a 

National Air Pollution Assessment (NAPA)–the next phase of NATA (for the year 2008)–is 

being developed to include both air toxics and NAAQS pollutants in the context of exposure and 

health risk and will further expand to include ecosystem and multi-media impacts. In addition, as 

OAQPS moves toward more comprehensive, “sector-based” approaches for addressing sources, 

there is a need to understand the amount and species of pollutants emitted from entire sectors and 

the technological options that are most cost effective in reducing highest source risks. This will 

 

10 NAS “Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties,” Oct., 2005. 11 The Multi-Pollutant Report: Technical Concepts & Examples: http://www.epa.gov/air/airtrends/studies.html. 

8 
require new tools and models that can be used by decision makers to evaluate sectors in an 

integrated manner. 

Presently, the Clean Air Research program has a number of largely disconnected efforts 

regarding multi-pollutant research. These include varied efforts in atmospheric modeling, 

exposure measurements, and source characterization (methods and health). As described below 

in LTG 2, ORD multi-pollutant efforts are adopting a source-to-health outcome paradigm, with 

near-road impacts as the prototype for development of its research framework. 

e. Assessing Health and Environmental Improvements Attributable to EPA Actions. There have 

been marked reductions in several of the NAAQS pollutants over the last two to three decades. 

Sulfur dioxide reductions and controls in combustion emissions have led to major environmental 

improvements with reduced acid rain and deposition, but the benefits of reductions in other 

pollutants have been more difficult to demonstrate in terms of health or ecology. Because of the 

tremendous complexities involved in attributing changes in health or ecological status to changes 

in air pollution alone, OAR has been challenged to find acceptable methods to show the benefits 

of its decision making. As such, OAR has communicated the need for tools to measure the 

impacts (in terms of benefits or reduced risk) of its decisions–an issue also known by the term, 

“accountability.” CAAAC has called for an “overarching accountability framework” that 

includes a systematic effort to track air quality achievements and evaluate air program results. 

According to CAAAC, the EPA needs to move beyond the current approach of relying 

predominately on air quality measurements and develop and apply the capability and capacity to 

monitor, assess, and report on how changes in emissions impact air quality, atmospheric 

deposition, exposure, and effects on human health and ecosystems. There is also interest in 

ensuring that use of a specific technology or combinations of technologies to reduce air 

emissions in response to a particular regulatory requirement does not result in other unintended 

environmental emissions or releases of concern. 

Currently, there exists no formally sponsored ORD effort to address these needs largely because 

of the complexity of the task and the many factors that exist as potential confounding. The 

HHRP has initiated a cross-program discussion in an attempt to meet this need across program 

areas, but, to date, this generic program has lacked the resources to be implemented. The Clean 

Air Research program has been working with OAQPS to develop a framework tailored to its 

needs, which builds on pilot activities such that a broader model can be built and substantiated. 

This concept is being incorporated into the design of all planned Clean Air Research program 

undertakings. 

f. Indoor Air. People spend upwards of 90% of their time indoors. Understanding the infiltration 

of outdoor air with its diverse pollutants into the indoor environment is further complicated by 

contaminants from indoor sources. The public looks to ORIA for advice on indoor air problems, 

as well as overall guidance on the issue. ORIA, in consultation with ORD, generated a document 

entitled Program Needs for Indoor Environments Research, which included some key research 

needs related to chemical and biological indoor contaminants to support future OAR guidance 

and policy related to indoor exposure risks and guidance. Ideally, characterization of indoor 

pollutant exposures, arising from either indoor sources or infiltration from sources outdoors, 

provides the foundation for development of methods and strategies for controls and minimization 

9 
of risk. Among the issues in the public eye are those related to asthma induction or exacerbation 

(from contaminants or biological allergens), especially in children. On a different note, there is 

also a growing movement related to green building design that increasingly will require 

information that can be used to perform unbiased analyses of building materials selection and 

installation procedures. For those buildings already in existence, the development of mitigation 

strategies with assessments for their effectiveness are of great interest, especially those that 

examine the effectiveness of EPA’s Indoor Air Quality Tools for Schools guidance already in 

place (notably for schools located near major roadways). As such, in the implementation of the 

near-road research program, the Clean Air Research program is attempting to address selected 

information needs (e.g., school infiltration, effectiveness of solid and vegetative barriers). 

g. Ecological Research. The impact of air pollution on the ecosystem has long been appreciated, 

especially with regard to acid deposition. To that end, the work of ORD has contributed 

significantly to the steady reduction and ongoing assessments of that environmental stressor. 

Given the need to review the secondary NAAQS that address welfare (notably ecological) 

impacts of air pollutants, OAR continues to request support for data collection in the field and 

associated assessments. With the passage of the Clean Air Interstate Rule (CAIR) and Clean Air 

Visibility Rule (CAVR) in 2006, OAR’s requests are underscored by the desire to develop 

measures for eco-accountability. As such, identification of indicators and profiles of wet and dry 

sulfur deposition are voiced as priority needs by OAR. New technologies also have been 

requested to facilitate these assessments and to address related contaminants such as nitrogen 

deposition from atmospheric ammonia. With the recent Supreme Court decision on carbon 

dioxide (CO2) and growing climate and global change concerns, there likely will be an amplified 

cry for tool development and broad based assessments related to the interface of land and water. 

However, ORD’s investments in these activities are limited and have been diminishing because 

of increasing annual fiscal constraints. 

h. Global Climate Research. The recent Supreme Court decision on CO2 and climate has 

expanded greatly OAR’s interest in quantifying climate impact on health, air quality, and other 

socioeconomic and environmental systems. The linkages between air quality and climate are of 

growing importance, but little is understood. OAR has increased interest and need for enhanced 

models to incorporate better chemical, transport, and meteorological parameters both regionally 

and globally. The interactions between climate change and air pollution loom as a major issue of 

the 21st century, crossing all offices and program areas. OAQPS, in particular, has the challenge 

of trying to forecast the impact of longer ozone seasons (compounded by enhanced PM by 

transformation) and perhaps higher ozone levels on exposed human populations and ecosystems. 

The Clean Air Research program is partnering with the Global Change Research program to 

frame the nature of the issues and define specific research issues that can be integrated into both 

programs to maximize effectiveness. At present, these activities are limited to assessments and 

the development of a research framework. 

i. Research to Support the Regions, States, and Tribes. The implementers of rules and policy 

decisions are faced with many technical issues. They rely on tools and models developed by 

ORD, as well as the latest technologies for monitoring and analyses. Cost efficiencies and quality 

assurance are major concerns when applying technological changes especially for rule changes. 

ORD must communicate these technology advances and assist in their field applications. The 

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Regions, States, and tribes also have unique and often immediate needs because of their specific 

geographies, socioeconomics, etc., that deserve attention from ORD. Assistance in the way of 

advice and consultation frequently is provided and opportunities for real-world field testing 

opportunities for ORD research activities is constantly sought. Nevertheless, the balance between 

long-range policy targeted research and crisis or problem-solving research can, at times, be 

strained and, thus, requires continual communication and nurturing. 

2. External Program Reviews 

A number of external organizations have performed reviews of the Clean Air Research program 

and have provided critical feedback and recommendations that have been used to improve 

program design. 

Under Congressional directive, the NAS NRC identified 10 priority research topics in a series of 

EPA sponsored reports published from 1998 to 2004. These documents provided key guidance to 

the development of the Clean Air Research program and continue to be a major influence on its 

evolution. The last report, released in April 2004, identified major science drivers and challenges 

associated with managing the science to address key remaining research questions. These are 

briefly articulated below along with the program’s response. 

Overarching Science Drivers 

• Completing the PM emissions inventory and PM air quality models necessary for NAAQS 

implementation and for informing health research. New data on emissions are being added 

regularly to databases used by OAR and the States to upgrade their inventories, and new 

technologies are being developed and applied to sources previously poorly characterized. 

New volatile organic compound (VOC) transformation algorithms are being incorporated 

into the Community Multiscale Air Quality (CMAQ) modeling system that have improved 

accuracy and served specific program office needs. 

• Developing a systematic program to assess the toxicity of different components of the PM 

mixture. Bioassays are being applied uniformly to sources and emission/PM attributes to 

assess their relative importance to toxic outcomes. Complementary study designs are being 

used in human and animal studies to enhance extrapolation. 

• Enhancing air quality monitoring for research. Improved coordination with OAQPS, States, 

and Regions shift current air monitoring from primarily assessing compliance toward serving 

multiple purposes, such as air quality forecasting, episode alerts, exposure characterization, 

health studies, and impacts of regulations. Workshops have proved to be important venues 

for enhancing communication of research needs for input into monitoring strategies, as well 

as tool development for data clarity and access. 

• Planning and implementing new studies of the effects of long-term exposure. EPA has funded 

new long-term studies including a 10-year prospective multicity study of atherosclerosis 

(MESA-Air; see below). 

• Improving the relevance of toxicological approaches. Improved study designs, focus on the 

source-to-health outcome paradigm, and attention to species dosimetry will better link the 

toxicology and epidemiology. Interdisciplinary and cross-Laboratory/Center project planning 

allows leveraging of the science and complementary studies. 

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• Integrating disciplines. Discipline integration in study design and cross-project leveraging is 

enhancing program efficiency and data interpretation. 

• Moving beyond PM to a multi-pollutant approach. A multi-pollutant program has been 

initiated in LTG 2 (see below) using a source-to-health concept design. 

• Accountability: The concept of accountability (demonstrating an impact) is being 

incorporated in all program areas. While a framework is being developed for broader Clean 

Air Research application and OAR use, specific pilot projects have been initiated central to 

this goal and, wherever possible, programs such as near-road have incorporated 

accountability (e.g., impact of mitigation strategies) into project designs. 

Challenges to Science Management 

• A higher level of sustained program-science integration and interaction. Under the direction 

of a National Program Director, EPA’s multiple air-related programs (NAAQS and HAPs) 

have been integrated into a single Clean Air Research program to improve integration, 

efficiency and science utility. As the climate issue grows, the linkages between air quality 

and climate must be strengthened to meet the evolving demands of a sustained high level of 

air quality management. 

• An integrated multidisciplinary research program that strives to elucidate the science and 

linkages across the source-to-health outcome framework. Using the MYP as a guide, 

research planning and execution will move ahead to maximally leverage resources and 

provide the most complete understanding possible of the science questions vetted through the 

RCT in the development of the Clean Air Research program agenda. 

• Stronger tools are needed to synthesize the large amounts of new information being 

developed in the Clean Air Research program to support air quality decisions. Program 

integration and improved access to and development of databases and web based information 

have been undertaken. Regularly scheduled cross-organizational (Laboratory and Center) 

meetings and coordination with other programs (e.g., HHRA, Global, HHRP) and client 

offices (e.g., OAQPS) help assure effective targeting of research and communication of 

findings. 

• A continuing mechanism for independent review and oversight of the program. The program 

has been reviewed by an external panel of experts (BOSC). A program review occurred in 

March 2005 and a mid-cycle review was conducted in September 2007. These periodic 

programmatic reviews supplement independent science peer review of the program, along 

with Laboratory, divisional, and peer review mechanisms in the extramural grants program. 

A mechanism for gaining access to program science-oriented advisors to meet annually to 

provide insight and critique is being explored. 

• Multi-pollutant assessments require strong interdisciplinary research framed by its utility to 

the client/user: The program has partnered with its OAR and its Regional clients to develop a 

research agenda that feeds their need to better understand the science linkages from source 

emissions to health outcomes that will lead to the development of better tools and models for 

decision-making. 

The select-subcommittee of EPA’s BOSC that reviewed the PM and ozone programs in March 

2005 made a number of general and specific recommendations. These recommendations (see 

below) have been incorporated into the current MYP. 

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• The LTGs be reworded to succinctly focus on the essential responsibilities and desired 

direction of the program. The revised LTGs contained in this MYP are consistent with the 

BOSC recommendations. 

• The MYP include a discussion indicating how the goals set out by the NRC flow into the 

cross-cutting research issues and how these are embodied under the two LTGs. If this 

discussion is in the Research Strategy for the Program, the MYP needs to be organized to 

make the connection between the research and the NRC goals obvious. The MYP as 

described under its LTGs provides this research strategy that now encompasses more than the 

NAAQS and orients to the source-to-health outcome paradigm. The PM program historically 

has been aligned closely with the NRC topic areas and continues to be so. PM publications 

are categorized as such, but across the Clean Air Research program, the research that flows 

from the two LTGs is envisioned to support the new paradigm. 

• The PM-Ozone Program should commit to maintain the strong balance between intramural 

and extramural research. This MYP maintains that balance and fully integrates the 

extramural (NCER: Science to Achieve Results–STAR) program activities (approximately 

35%) with the intramural program comprising approximately 65% (inclusive of staff and 

program infrastructure). The research activities complement or elaborate upon one another to 

provide the integrated research that addresses OAR priorities. 

The full BOSC report can be found at http://www.epa.gov/osp/bosc/pdf/pm0508rpt.pdf, and 

EPA’s response can be found at http://www.epa.gov/osp/bosc/pdf/pm0602resp.pdf. The midcycle (2007) BOSC report can be found at http://www.epa.gov/osp/bosc/reports.htm. 

3. ORD Laboratories and Centers 

The research described in the Clean Air Research program MYP is conducted by investigators of 

ORD’s National Exposure Research Laboratory (NERL), National Health and Environmental 

Effects Research Laboratory (NHEERL), and National Risk Management Research Laboratory 

(NRMRL) and by awardees of its extramural grants program, funded through the NCER STAR 

program. In addition, the National Center for Environmental Assessment (NCEA), while not 

funded through this MYP, plays a major role summarizing the latest scientific findings related to 

the effects of PM, ozone and other criteria pollutants to support development of future NAAQS 

standards. NCEA also conducts risk assessments (IRIS values) for high priority air toxic 

pollutants including associated assessments of residual risk after implementation of controls. 

There are also collaborative projects between ORD Laboratories and Regional scientists referred 

to as RARE (Regional Applied Research Effort) to enhance real-world research applications or 

to pursue unique opportunities. 

ORD Clean Air Research program investigators are in a unique position within the research 

community because they conduct research to address pressing science data gaps that underlie 

regulations, as well as develop models, tools, and strategies to implement regulations or 

otherwise mitigate air pollution. The diverse nature of problem-solving research requires both 

breadth and depth across diverse scientific disciplines. ORD acquires the needed skill mix 

through the coordinated use of its intramural scientists housed within ORD’s Laboratory 

structure, as complemented by the many talents of the academic community accessed through the 

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STAR program in NCER. ORD supports leading-edge research across the air pollution sciences. 

These include integrated epidemiological, clinical, and toxicological investigations of the health 

effects of PM and co-pollutants, with a systematic focus on components and sources, the 

identification and quantification of factors influencing actual human exposures, the development 

of ambient monitoring methods and air quality models used for compliance purposes, the study 

of basic atmospheric sciences to support these air quality models, and the development of 

specialized technologies for the measurement and control of diverse emissions. ORD is also 

unique as a research institution because of the close proximity of its intramural exposure, health, 

atmospheric science, and engineering researchers. The Clean Air Research program continually 

strives to coordinate its research agenda to the extent possible to provide coherent and relevant 

data and to maximize its ever-strained resources. 

4. Client-Partners for Air Research 

ORD has a unique relationship with the prime users of its research products. The users are 

involved in the prioritization of its research and, depending on the nature of the research, the 

users function as collaborators. Such collaborations help shape the product and ensure its 

relevance and utility. The client-partner for the work described in this MYP is EPA’s Air 

program office, OAR. ORD’s research to address uncertainties in the standard-setting process 

also deals with the rule implementation needs. Implementation research assists EPA Regions, 

States, tribes, and regional planning organizations (RPOs) in their activities to reduce ambient 

concentrations of air pollution, exposures, and, ultimately, adverse health effects. ORD research 

is key to its own office (NCEA) responsible for NAAQS pollutant science assessments (and, 

secondarily, the air toxics) used by the Agency in risk management decisions as described in the 

HHRA MYP. 

In addition to supporting EPA’s regulatory process, ORD’s Clean Air Research program also 

supports environmental protection standard setting beyond the borders of the United States. 

Several countries in the European Union rely on ORD’s research in environmental decisionmaking, and international organizations such as the World Health Organization rely upon ORD 

outputs and expertise to inform their activities and conclusions. Similarly, ORD works with 

scientists and policy-makers from numerous countries (e.g., Canada, Mexico, Netherlands, 

Germany) through informal collaborations or more formal Memoranda of Understanding to 

promote the exchange of the latest scientific knowledge in support of policy development. 

5. ORD Partners in Research 

Air pollution research is also conducted outside the EPA, and ORD keeps abreast of this research 

and coordinates its own activities with these to the extent possible. In some cases, a close 

collaborative relationship exists, such as with the National Oceanic and Atmospheric 

Administration (NOAA). ORD has worked closely with NOAA for more than 35 years with a 

focus on the development of air quality models appropriate for atmospheric research, standard 

implementation, and pollution forecasting. This relationship remains strong with the growing 

need for integration with changing meteorological and climate sciences. 

14 
HEI, funded jointly by EPA and the motor vehicle industry, is another important partner in the 

support of ORD’s mission. HEI-sponsored research is coordinated with ORD/EPA and 

conducted through requests for proposals, drawing from the diverse academic community to 

focus on issues or questions not readily pursued within the government laboratory structure. 

Notably, HEI-sponsored activities in the independent reassessment of epidemiological findings 

have been invaluable to EPA in the regulatory decision-making process. Research support also is 

provided by the National Institutes of Health, including the National Institute of Environmental 

Health Sciences (NIEHS) and the National Heart, Lung, and Blood Institute (NHLBI), and select 

industrial organizations, including the Electric Power Research Institute (EPRI) and the 

Coordinating Research Council (CRC)—the latter through its support of HEI. In recent years, 

ORD has co-funded requests for applications (RFAs) and workshops with NIEHS and NHLBI 

and continues to explore opportunities for similar co-funded initiatives. Most recently, the Clean 

Air Research program has initiated efforts to coordinate its extramural research with the funding 

agencies already noted along with the California Air Resources Board, which has a significant 

air pollution research agenda. 

In an effort to better coordinate with the broader air pollution research arena, EPA takes the lead 

role in communicating its research goals and program structure with other public and private 

organizations through two coordinating bodies: 1) NARSTO12 and 2) the White House CENR, 

AQRS.13 These groups meet regularly (about monthly) to communicate program findings and 

directions to coordinate and leverage activities wherever possible. In addition, there are several 

groups conducting air quality studies, including ambient PM measurements by the U.S. 

Department of Energy (DOE) in the upper Ohio River Valley and multi-agency state efforts in 

California and Texas. Multi-state organizations such as Northeast States Coordinated Air Use 

Management and RPOs in the Midwest also are sponsoring studies of ambient air quality. In 

emission characterization and inventory development, the U.S. Department of Agriculture is 

providing support for research to improve emission inventories for ammonia from agricultural 

operations. There are also several projects related to emission inventory improvement and air 

quality model application being conducted by States and the RPOs. Further emission inventory 

and characterization work is being conducted or supported by EPRI, the American Petroleum 

Institute and Gas Technology Institute, and the CRC. 

As noted earlier, EPA stays abreast of this work (both health and implementation research) via 

its formal participation in the CENR and NARSTO, continuous interactions with Federal 

colleagues, and through scientific and technical conferences and organizations. Information on 

these complementary research activities is taken into account by both principal investigators and 

ORD scientific and technical management when research needs are evaluated, and efforts are 

undertaken to meet the priorities of OAR and the goals of the MYP. Presently, ORD is coleading an effort with HEI to promote coordination of ongoing research across these many 

sponsors and to provide a central resource of information for research on air pollution issues. 

 

12 Formerly an acronym for “North American Research Strategy for Tropospheric Ozone,” the term NARSTO has 

become simply a wordmark signifying the tri-national, public-private partnership for dealing with multiple features 

of tropospheric pollution, including ozone and suspended particulate matter. 

13 http://esrl.noaa.gov/csd/AQRS/ . 

15 
EPA also works cooperatively with the Department of Defense through the Strategic 

Environmental Research and Development Program (SERDP) to conduct research of interest to 

both agencies. SERDP annually issues statements of need, many of which have air emissions 

implications. Similarly, partnerships have been formed with DOE to evaluate promising 

technologies to reduce air emissions from coal-fired power plants and other energy sources. 

6. Resources 

The research described in this MYP covers the next 5 years and is based on an assumption that 

the total available resources will remain nominally constant. EPA allocated approximately $78 

million dollars and 245 full-time equivalent personnel to air research in fiscal year 2007. Of the 

total funding, $42 million was for personnel compensation and benefits, travel, information 

technology, operating expenses, capital equipment, and repairs and improvements. The 

remaining $36M was for research and support expenses spent via contracts and grants. The 

president’s fiscal year 2008 budget requests $81M and 236 full-time equivalent personnel for air 

research. 

II. THE CLEAN AIR RESEARCH MULTI-YEAR PLAN 

A. Changes from the Previous MYP 

This MYP combines and integrates three previous MYPs and research strategies (PM, ozone, 

and HAPs) into a single plan to better coordinate and leverage research across all themes. Earlier 

MYPs approached each program area separately with little cross-theme coordination and 

integration. Budgeting (both proposals and tracking) was also separate. As already noted, the 

science and regulatory programs are evolving toward a multi-pollutant perspective that better 

reflects the realities of human exposures and offers the potential for more effective control and 

public health protection. 

At the core of this MYP is a major shift in ORD’s approach to research in the air pollution 

sciences. Previously, each MYP relied on several loosely connected L/C-focused LTGs 

addressing a wide range of specific science supporting regulatory functions. The present MYP is 

shaped around two overarching LTGs that continue to support the regulatory requirements of the 

program office while developing the science to link health effects to air pollution sources and 

components. The latter approaches air pollution from its origin as source emissions, through 

atmospheric transport and transformation, to exposure, dose, and human health outcomes. It 

emphasizes science planning coordination to leverage across programs and achieve efficiencies 

in both science and budget. To this end, this MYP has adopted a two-pronged approach: 

1. Continue to support the needs of EPA, and state and local governments, developing 

the underlying science for developing health-based standards to regulate air pollution 

regulations and developing tools to implement strategies to meet those standards to 

protect public health and the environment; and 

16 
2. Pursue scientific advances that will lay the foundation for the next generation of air 

pollution standards and management strategies. 

B. Long-Term Goals 

This dual approach is reflected in the adoption of two LTGs for this research plan: 

LTG 1. In accordance with EPA’s legislated mandate for periodic NAAQS assessments 

and assessment of HAP risks, advances in the air pollution sciences will reduce 

uncertainty in standard setting and air quality management decisions. 

(Short title: Reduce uncertainty in standard setting and air quality management 

decisions due to advances in air pollution science.) 

LTG 2. Air pollution research will reduce uncertainties in linking health and 

environmental outcomes to air pollution sources to support effective air quality 

management strategies. 

(Short title: Reduce uncertainties in linking health and environmental effects to air 

pollution sources.) 

The first LTG (LTG 1) supports the following two research themes: 

1) Developing the NAAQS and other air quality regulations; and 

2) Implementing air quality regulations. 

The second LTG (LTG 2) is oriented toward three research themes 

3) Launching a multi-pollutant research program, 

4) Identifying specific source-to-health outcome linkages, with initial emphasis on “near 

roadway” impacts, and 

5) Assessing the health and environmental improvements due to past regulatory actions. 

C. LTGs in Relation to Air Program Needs, Priority Science Questions and APGs 

EPA is mandated to periodically (at 5-year intervals) reassess the adequacy of the six NAAQS 

(PM, ozone, SO2, NO2, CO, and lead) and reaffirm or revise each specific standard. ORD 

provides and supports the science to conduct these assessments, as well as the science and 

engineering needed to implement the standards at the appropriate regulatory jurisdictions. In the 

case of HAPs, the CAA requires EPA to develop emission standards for sources, known as 

MACT standards, based on the best controlled similar sources. Following implementation of 

MACT, EPA must assess risks remaining to human health and the environment, and must 

promulgate additional emission standards if appropriate. Although secondary to the NAAQS in 

program priority, ORD can, under this revised MYP, similarly provide science related to these 

HAPs issues, particularly through project integration. 

17 
As can be seen in Figures 3 and 4, the critical science questions for the Clean Air Research 

program (as derived from the major policy challenges identified by our clients and external 

program reviews) flow into these two LTGs. The vision is that, over time, increasing emphasis 

will be given to multipollutant approaches. As critical steps in fulfilling the LTGs, the APGs will 

strategically reduce uncertainty in assessments, the impacts of which should be more readily and 

realistically measured. However, the progression of science is always incremental, and it is likely 

that in reducing some uncertainties others will be unveiled. Nevertheless, science has always 

built from such a process, and there is sufficient flexibility in the various products and the MYP 

to allow for midcourse adjustments. The specified APGs and related science products (APMs) to 

meet these goals evolved from deliberations within the EPA Air RCT and they have been vetted 

through senior management. 

18 
What is the role of physicalchemical characteristics of air 

pollutants in eliciting adverse 

short- and long-term health 

effects, especially in susceptible 

populations?

Which sources of air pollution 

most severely impact exposure 

and health, and how does this 

vary across the country?

What are the characteristics of air 

pollutant emissions from different 

types of sources, and how do 

transformations in the atmosphere 

affect air pollutant concentrations 

and human exposures?

What are the expected future 

concentrations of air pollutants, 

and how can we evaluate and 

manage their potential adverse 

consequences?

Science Questions Outcomes

PM standard revisions will more effectively address:

• Size fractions, components, and sources responsible for adverse health 

effects,

• Improved understanding of exposure-dose-response relationships,

• Health endpoints outside the cardiopulmonary system,

• Understanding mode-of-action of air pollutant-induced health effects, and

• Health effects in susceptible populations.

Use of air quality and receptor models to develop SIPs and control strategies 

and forecast air quality.

Use of advanced techniques to better characterize emissions and ambient 

concentrations of air pollutants, leading to improved risk management 

decisions. 

Use of advanced tools, models and technologies to formulate policies to 

reduce PM level in residual non-attainment areas.

Development of improved risk management strategies via better inventories 

and enhanced capacity to determine which sources contribute to measured 

ambient levels of PM.

Reduce uncertainty in standard setting and air 

quality management decisions due to advances in air 

pollution science 

Long-Term Goal 1

Figure 3. LTG I Critical Science Questions 

How can we assess and manage 

risks from real-world exposures 

involving complex mixtures of air 

pollutants that fall into multiple 

physical-chemical classes?

Which sources of air pollution 

most severely impact exposure 

and health, and how does this 

vary across the country?

How can we determine how past 

regulatory decisions have reduced 

exposures to air pollution and 

improved health outcomes?

Science Questions Outcomes

ORD research will be used to inform consideration of alternatives to a massbased standard and target air quality management strategies. 

EPA will develop and begin to implement approaches to assess the

effectiveness of regulations and control strategies in reducing impacts to 

the environment and human health.

ORD will identify technology performance information for air quality officials 

who will use that information to improve performance and minimize 

releases. 

Reduce uncertainties in linking health and 

environmental effects to air pollution sources

Long-Term Goal 2

Researchers and policy-makers will use ORD tools to understand 

relationships between sources and ambient air concentrations.

Federal, State and local agencies will use ORD tools to measure gradients of 

emissions from roads and to understand what these mean for exposure 

and risk.

Improve understanding of the contribution of specific sources to risks, thereby 

reducing the uncertainty associated with evaluating the public health 

impacts of those sources.

Establish relationships that provide the capability to directly link field 

measurements to health indicators.

Figure 4. LTG II Critical Science Questions. 

19 
LTG 1

In accordance with EPA’s legislative mandate for periodic NAAQS assessments and 

assessment of HAP risks, advances in the air pollution sciences will reduce uncertainty in 

standard setting and air quality management decisions. 

Under this goal, ORD highlights two themes that provide direct support to OAR’s mission: 1) 

development of the NAAQS and other air quality regulations and 2) implementation of the air 

quality regulations (see Figure 4). These themes focus on the standards that are used to regulate 

air pollutants in keeping with the traditional roles of ORD relative to the OAR regulatory 

program. Theme narratives are provided to demonstrate the continuities within the program with 

underlining of phrases to note their linkage to APGs in Tables 1 and 2. Satisfaction of individual 

APGs generally does not necessarily conclude research under that topic but, rather, registers a 

time point for assessment of the knowledge at that time as it relates to the regulatory need. This 

may impact a level of emphasis of this research thereafter or shifting of focus based on that 

knowledge. Some fundamental questions (e.g., regarding size, composition, susceptibility, model 

delivery) may require continued investigation to address ongoing program office needs. 

Theme 1: Support for the development of the NAAQS and other air quality regulations

ORD plays a key role in the development process of air quality standards. ORD peer-reviewed 

research results are the strong foundation on which ORD builds the assessment of both human 

health and environmental impacts for each air pollutant. ORD staff also is involved heavily in the 

design and review of the NAAQS policy options developed for the Administrator. Similarly, 

ORD staff is involved in the development of the toxicological data base and mode-of-action 

models, and their use in the HAPs risk assessment process, and in the various rule-making 

actions by OAR offices (e.g., OTAQ). At the highest level, ORD provides direct scientific 

consultation to the Administrator in proposed and final air regulatory decisions. 

Uncertainties exist in all scientific investigations, and the Clean Air Research program directs its 

attention to those of highest priority to its clients and the scientific community. Uncertainties 

surrounding coarse particles (PM10-2.5) were noted specifically in the promulgation of the most 

recent PM regulations. Also, there continues to be considerable interest in the significance of 

ultrafine particles, relative to fine particles (PM2.5), as to their potential role in causing adverse 

health effects. To address these questions, one research goal is to investigate exposures and the 

role of different PM size fractions in health outcomes (APG 1). Another priority of interest to 

OAR is exploring the potential for alternatives to the current PM mass-based standards. As the 

science has been more complex in this area than originally anticipated, research on exposure and 

health effects of PM components (APG 2) [some of which are among the 188 HAPs] is ongoing 

under LTG 1. Additional research on components is being conducted under LTG 2 (see below). 

Different views about the annual PM standard emphasize the need for additional studies on the 

health effects of long-term exposure to PM2.5 (APG 5). 

Much work continues on the potential exposure and health outcomes associated with air 

pollution. As per RCT-determined priorities, PM research occupies much of the program effort; 

however, some health research addressing specific pollutant-relevant questions is conducted as 

well. Ozone, for example, is the most ubiquitous oxidant in the ambient air and has known 

20 
21 

toxicity at regularly encountered levels. The essential database for ozone assessments largely has 

emanated from ORD research efforts over the past 30 years. In the past 10 to 15 years, PM has 

come to dominate the health program, but ozone questions are addressed as specific needs arise 

or when it can function as a model (e.g., genetic susceptibility). Recently, functional outcomes at 

concentrations well-below the NAAQS have been reported, and OAQPS has specifically 

requested that the research program conduct replicate studies at similar concentrations. However, 

these efforts remain modest. In another context, ozone has gained some prominence because of 

evidence of potential mortality impacts and morbidity at levels below the 1997 NAAQS. The 

Clean Air Research program monitors these studies but is not directly pursuing this issue. 

On the other hand, questions about PM and co-pollutant (including ozone) risks (APG 5) is 

gaining prominence on the health science agenda. Air toxics research will be undertaken for 

specific HAPs that are most prominent in PM-polluted air sheds, especially if linked to mobile 

sources. To that end, the relative and interactive roles of specific pollutants in causing effects 

continue to be investigated to define causation and refine our understanding of biologic modes of 

action (APG 6). Most health research supporting air toxics IRIS assessments is found in other 

MYPs (e.g., HHRP, HHRA, and Homeland Security.) 

Intrinsic to this research is the evolving importance of “who is susceptible to which effects,” 

defining factors affecting susceptibility (APG 3) to adverse health outcomes, and examining 

gene-environment interactions. Recent work on susceptibility has uncovered the potential for 

health effects of air pollutants beyond the cardiopulmonary system (APG 4), which may have 

implications for additional susceptible subgroups. With risk assessments providing the basis for 

development of risk management options, providing up-to-date information on exposure-doseresponse relationships (APG 7) is a key area of program support. Targeted studies to address the 

level and duration uncertainties with ozone have been considered and, if implemented, may 

displace lower priority PM research. 

To the extent possible, the health research is interdisciplinary, not only across health disciplines 

but across the physical sciences, including exposure science and air quality assessments. As 

such, maximum power is gained to address potential interactions among pollutants, as well as to 

assessments of specific roles of other pollutants, including selected air toxics, in causing health 

effects. 
2008 2009 2010 2011 2012

Improved information for hazardous air pollutants

Roles of different PM size fractionsIntegrated multiple pollutant research program strategy

Exposure to PM components and throle in health effect

Factors affecting susceptibility to adverse health outcomesEvidence for effects of air pollutants beyond the cardiopulmonary systemEffects of long-term exposure to PM2.5

Importance of key biologic pathwaysAmbient concentraand exposure-doseresponse relationsh

Advanced air quality models

Advanced techniques for source and ambient PM, precursors, and toxics

Data and tools to assess the importance of particles in residual nonattainmentAir quality modeling system that couples meteorology and provides early warning regarding ozone and PM 2.5

Emissions factors and chemical composition data for dispersed sources of air pollutants

Improved sourcereceptor based me

Framework to assess and modelsthe effectiveness of air pollution regulations and control strategies 

Tools to link health and ecosystem impacts to air pollution sources 

Significance of neaemissions/exposureand related health rfrom mobile source

1 - Support development of NAAQS and other air quality regulations2 - Support for implementation of air quality regulations3 - Pursuing a multi-pollutant approach4 - Identifying source-to-health linkages5 - Assessing health and environmental improvements due to past Agency activities

Multi-city/multi-pollustudies to assess threlative health impasources Approaches to relasources/ambient aihealth effects

Evaluate whether ctechnologies are achieving the reducanticipated 

Refine accountabiliframework

Research Themes

Figure 5. APGs by Theme. [Note that some APGs relate to more than one theme, but have been assigned t
Table 1. APGs and APMs for LTG 1, Theme 1 

APG/APM Title Year 

Due 

Lead 

Lab 

APG 1 Evaluate exposures to different PM size fractions and determine 

the role of those fractions in particle-associated health effects 

2009 NHEERL

APM 1 Characterize physiologic and biochemical responses of individuals, 

animal models, or cultured cells to different size PM fractions and define 

the mechanisms by which each size fraction causes effects 

2009 NHEERL

NCER 

APM 2 Provide exposure and health effects data on urban and rural coarse PM 

in support of the NAAQS 

2009 NHEERL 

NCER 

APG 2 Evaluate exposure to PM components and the role of those 

components in particle-associated health effects 

2012 NHEERL

APM 3 Report on how the presence and levels of PM components impacts 

particle related health effects 

2009 NHEERL

APM 4 Identify health effects associated with components of ambient particulate 

and gaseous co-pollutants 

2012 NHEERL 

NCER 

APM 5 Identify new biomarkers of exposure and/or effects to specific PM 

components and associated gases 

2011 NHEERL 

NCER 

APM 6 Provide a comparative toxicity testing framework and rank the relative 

potency of PM components, testing particles from a broad range of 

different sources including mobile and industrial sources 

2012 NHEERL

NCER 

NRMRL 

APM 7 Develop data on the size distribution and detailed chemical composition 

of combustion-generated particles produced from full- and pilot-scale 

systems for use in real time inhalation toxicology studies 

2008 NRMRL 

APM 8 Complete field data collection for field studies to assess ambient, indoor, 

outdoor, and personal exposure to PM constituents and co-pollutants 

with potential for short-term health effects and compile a database of 

toxic agent concentrations, exposures, participant activities, and 

exposure factors 

2008 NERL 

APM 9 Develop data and models to evaluate relationships among PM size, 

components, sources, ambient concentrations, and personal exposures 

2010 NERL 

 APG 3 Elucidate the susceptibility and vulnerability factors that increase 

risk with adverse health outcomes associated with air pollutants 

2011 NHEERL

APM 10 Report on the results of studies illustrating how factors of susceptibility 

impact air pollution responses 

2009 NHEERL

APM 11 Determine the extent to which genetic polymorphisms present in a 

significant portion of the population or differences in gene expression 

patterns in animal models explain why some people are more 

responsive to air pollutants than others 

2011 NHEERL

NCER 

APM 12 Determine whether there are host susceptibility factors, such as disease 

phenotype, lifestyle, or life stage, that make people with cardiovascular 

and/or pulmonary disease more susceptible to the effects of air 

pollutants 

2011 NHEERL 

NCER 

APM 13 Evaluate whether there are pharmaceutical or dietary interventions that 

can protect susceptible populations from the effects of air pollutants, 

and, if so, what are the mechanisms by which these interventions 

protect people? 

2011 NHEERL

NCER 

APM 14 Develop data and models to identify subpopulations with 

disproportionately high exposures to air pollutants 

2011 NERL 

APG 4 Provide exposure-based evidence for systemic effects of air 

pollutants other than those on the cardiopulmonary system 

2011 NHEERL

APM 15 Characterize the long-term health effects of short- and long-term low- 2010 NHEERL
APG/APM Title Year Lead 

Due Lab 

level exposure to air pollutants NCER 

APM 16 Evaluate the importance of early life exposures to air pollutants, and 

whether they are predictive of future effects later in life [also under 

Susceptibility] 

2011 NHEERL

NCER 

APM 17 Characterize the mechanisms by which air pollutants affect extracardiopulmonary organ systems and associated effects 2010 NCER 

NHEERL

APG 5 Provide an assessment of long-term exposures to fine particulate 

matter (PM2.5) and gaseous co-pollutants, specifically nitrogen 

oxides, as determinants of regional and intra-urban differences in 

the prevalence of subclinical indicators of cardiovascular disease 

2011 NCER 

APM 18 Develop a model for assessing regional and intra-urban differences in 

ambient long-term PM concentrations in nine U.S. communities 

2009 NCER 

APM 19 Evaluate the association of the prevalence of subclinical indicators of 

cardiovascular disease with regional and intra-urban differences in 

estimated long-term exposures to PM2.5

2010 NCER 

APM 20 Evaluate the modification by co-existing health conditions (e.g., 

diabetes, hypertension, obesity) and individual-level factors (e.g., 

race/ethnicity, gender) of the association of the prevalence of subclinical 

indicators of cardiovascular disease with estimated long-term PM 

exposures 

2011 NCER 

APG 6 Evaluate the importance of key biologic pathways in explaining 

how air pollutants cause adverse health outcomes 

2012 NHEERL

APM 21 Determine if there is a common molecular mechanism (e.g., production 

of oxidative stress, phosphatase inhibition, disruption of iron 

homeostasis) through which air pollutants induce toxicity. 

2012 NHEERL

NCER 

APM 22 Identify the mechanisms by which air pollutants cause adverse health 

effects 

2012 NCER 

NHEERL

APG 7 Characterize the ambient concentration and exposure-doseresponse relationships for PM and other priority air pollutants 

2012 NHEERL

APM 23 Characterize the effects of ozone exposure in selected populations at 

exposure levels near the standard 

2010 NHEERL

APM 24 Can predictive exposure-dose-response models be developed to 

improve the accuracy and precision of predictions of human health risk 

from experimental data from animal and in vitro experiments? 

2012 NHEERL

APM 25 Report estimates from epidemiological studies of changes in health 

outcomes associated with changes in ambient PM2.5

2010 NCER 

Theme 2: Support for implementation of air pollution regulations 

 Development of strategies to meet national air pollution regulations for PM and ozone requires 

extensive knowledge about current ambient concentrations, sources that contribute to the 

measured levels, and the impact of emissions and associated atmospheric processes on future air 

quality. ORD provides fundamental science to develop and improve tools that are essential to air 

quality management at all levels, including OAR, Regions, States, and tribes. The State 

Implementation Plans (SIPs) that provide details on actions that will be taken to reduce 

emissions are heavily dependent on the models and other products produced under this research 

theme. CMAQ (APG 9, 11) is widely used by States to inform their SIP development. CMAQ is 

updated annually and improved based on the latest research on emissions (APG 8) and 

24 
atmospheric science (APG 12) from ORD and the broader air quality research community. In 

addition to these inputs, CMAQ must be coupled with meteorology models (APG 9) to generate 

future estimates and forecasts (APG 12) of ambient ozone and PM. Similarly, efforts are 

underway to link CMAQ to climate models as the science moves toward a more realistic 

approach to studying climate and air pollution interactions (found in the Global Change Research 

Program). As these multi-pollutant (one-atmosphere) models are refined, new emission factors

(APG 13) and refinements are needed at local and community scales to better estimate 

population exposures to HAPs for risk assessment. Indeed, assessing exposures with empirical 

field data and model development are important links between source emissions, atmospheric 

transformation products, and human exposure. Source apportionment (APG 10) science is also a 

key component of this theme. It depends both on measurement techniques (APG 10) to 

characterize sources and ambient concentrations and receptor-based models (APG 14). The 

identification of source categories contributing to ambient concentrations provides the basis for 

targeted, cost-effective control strategies. Hence, the broad use of these implementation tools 

requires not only that ORD conduct high-quality relevant research, but also provide its key 

clients with the results in understandable and useful formats. 

The issue of HAPs (air toxics) ranks highly among OAR and regional priorities, but second 

to PM and ozone. As such, compared with ORD’s research investment on the PM issue, 

including co-pollutants, dedicated research on air toxics is relatively small. The MYP includes 

one goal to improve emissions, concentrations, and exposure estimates for HAPs (APG 8). 

Table 2. APGs and APMs for LTG 1, Theme 2 

APG/APM Title Year 

Due 

Lead 

Lab 

APG 8 Provide improved measurement systems, data to better quantify 

and estimate emissions, concentrations, and exposures, and 

health effects information for indoor and ambient hazardous air 

pollutants 

2008 NRMRL 

NERL 

NHEERL

APM 26 Demonstrate improved methods for measuring ambient and personal 

concentrations of acrolein and 1,3 butadiene 

2008 NERL 

APM 27 Enhance air quality and exposure modeling tools to address finer 

scale air toxics concentrations and exposures 

2008 NERL 

APM 28 Collect and analyze existing data to understand critical factors which 

influence relationships between human exposure and ambient air toxic 

concentrations (existing APM 32) 

2008 NERL 

APM 29 Develop and validate the Jet REMPI technology for real-time 

measurement of trace organic air toxics from multiple sources. 

(APMs 30 and 278 are consolidated) 

2008 NRMRL 

APM 30 Update AP-42 emission factors for landfills 2008 NRMRL 

APM 31 Provide a summary report of past results and future directions for the 

air toxics research program under the Multipollutant Air Research 

Program and how IRIS risk assessment health effects support needs 

will be addressed 

2008 NHEERL

APG 9 Provide advanced air quality models that incorporate the latest 

atmospheric and emissions data to OAR and States

2008 NERL 

APM 32 Deliver to OAR the simplified and evaluated regulatory version of the 

PM chemistry model (existing APM 386) 

2007 NERL 

25 
APG/APM Title Year Lead 

Due Lab 

APM 33 CMAQ model system release and evaluation, including improved 

capability for aerosol processes, especially secondary organic aerosol 

production 

2008 NERL 

APM 34 Release peer reviewed EPA receptor modeling tools to be used by 

States to enhance their ability to develop SIPs 

2008 NERL 

APM 35 Transfer information to OAR and States regarding characteristics of 

open burning of biomass in wild and prescribed fires (existing APM 

224) 

2008 NRMRL 

APM 36 Produce a prototype tool to improve the geographic allocation of 

emissions for use in air quality models 

2008 NRMRL 

APG 10 Deliver new and improved techniques to measure and 

characterize source and ambient concentrations of PM and PMrelated precursors and toxics 

2009 NRMRL 

NCER 

APM 37 Verification of Portable Optical and Thermal Imaging Devices for 

LDAR 

2009 NRMRL 

NERL 

APM 38 Evaluate and improve methods to characterize ammonia (including 

ammonia nitrate and ammonia sulfate) concentrations in the ambient 

environment 

2009 NRMRL 

APM 39 Provide to OAR, States, and the scientific community improved 

methods for organic speciation of fine particles (existing APM 319) 

2007 NERL 

APM 40 Provide to OAR, States, and the scientific community improved 

methods for measuring the organic carbon and elemental carbon 

fractions of PM (existing APM 320) 

2007 NERL 

APM 41 Improve measurement methods for molecular tracer species and 

identify new molecular tracers. 

2009 NCER 

APG 11 Provide models, data, and tools to better manage PM in the 

atmosphere, including carbonaceous particles that contribute to 

high levels of PM in areas of the country where NAAQS 

attainment will linger even after national rules are implemented. 

2011 NRMRL 

NCER 

APM 42 Study secondary organic aerosol formation mechanisms, including 

cloud processing, aromatic precursors, and biogenic precursors 

2008 NCER 

APM 43 Improve linkages between emission sources and atmospheric 

transformation processes for primary carbonaceous PM and 

secondary organic aerosol precursors 

2008 NCER 

APM 44 Complete development of novel analytical methods that can be used 

to determine the chemical and physical properties of combustion 

emissions and atmospheric aerosols and provide guidance on their 

use to OAR and State agencies 

2008 NRMRL 

APM 45 Integrate receptor, source-based, and inverse modeling for PM source 

apportionment. 

2009 NCER 

APM 46 Improve the SOA chemistry model for CMAQ to include additional 

anthropogenic SOA sources. 

2011 NERL 

APM 47 Produce an operational emissions allocation tool, compatible with the 

OAQPS Emissions Modeling Framework 

2011 NRMRL 

APM 48 Measurement of ammonia air-surface exchange in forest and 

agricultural landscapes 

2011 NRMRL 

APM 49 Evaluate computational atmospheric chemistry approaches to 

determine whether they can be used to develop chemistry sub-models 

2011 NERL 

APM 50 Improved CMAQ modeling system for use in urban-scale residual 

nonattainment areas 

2011 NERL 

26 
APG/APM Title Year Lead 

Due Lab 

APM 51 Develop CMAQ linkages to global chemical transport model 2011 NERL 

APG 12 Develop modeling systems that couples air quality and 

meteorology models for better estimates and forecasts of 

ambient ozone and PM2.5

2011 NERL 

APM 52 Develop and test a prototype 2-way coupled WRF-CMAQ modeling 

system 

2008 NERL 

APM 53 Analysis and evaluation of PM forecast simulations over the 

Continental United States using a developmental version of CMAQ 

2009 NERL 

APM 54 CMAQ modeling system used for fully operational daily forecasting of 

both ozone and PM2.5

2011 NERL 

APM 55 Develop improved chemistry model for CMAQ to predict ambient 

concentrations of organic and inorganic nitrates in PM2.5 

2010 NERL 

APM 56 An operational 2-way coupled WRF-CMAQ modeling system will be 

released publicly 

2011 NERL 

APM 57 Apply the prototype 2-way coupled WRF-CMAQ model to evaluate the 

regional air quality and climate impacts of future-year anthropogenic 

emissions scenarios 

2011 NERL 

NRMRL 

APM 58 Evaluate impact of two-way coupled WRF-CMAQ on regulatory 

applications 

2011 NERL 

APG 13 Provide new emissions factors and chemical composition data 

for dispersed sources of air pollutants, including off-road 

vehicles (airplanes, ships, construction equipment) to directly 

support State efforts to improve emissions inventories 

2011 NRMRL 

APM 59 Transfer data to OAR and the States on the chemical characterization 

of carbonaceous PM as a function of particle size. 

2008 NRMRL 

APM 60 Enhance and update the SPECIATE database of emission profiles by 

source category for air quality modeling and source-receptor modeling 

applications 

2008 NRMRL 

APM 61 Transfer to OAR and the States improved PM and HAP emission 

factors and chemical source profiles for commercial aircraft engines 

2010 NRMRL 

APM 62 Determine emission factors and characteristics of open burning of 

agricultural fires and wild and prescribed forest fires for ozone, PM, 

and HAPs 

2011 NRMRL 

APM 63 Characterize HAPs and other NAAQS-related pollutants from priority 

off-road sources. 

2011 NRMRL 

APM 64 Identify emissions of regulated and unregulated pollutants during the 

use of alternative fuels and fuel additives in on-road motor vehicles 

2011 NRMRL 

APG 14 Provide new and improved source-receptor based methods and 

models, and associated input data (e.g., source markers) to better 

quantify ambient concentrations and human exposure for coarse 

and other PM size fractions, as well as related PM components 

identified by health researchers as important. 

2012 NERL 

APM 65 Improve source apportionment through the development of enhanced 

sampling and analytical methods and receptor-based models. 

2012 NERL 

APM 66 Evaluate and improve receptor modeling for PM source apportionment 2009 NCER 

APM 67 Provide new and improved source-receptor-based models to quantify 

the sources of coarse and other PM size fractions. 

2011 NERL 

APM 68 Evaluate exposures to sources of coarse and other PM size fractions 

identified by health researchers as important. 

2012 NERL 

27 
LTG 2 

Air pollution research will reduce uncertainties in linking health and environmental outcomes 

to air pollution sources to support effective air quality strategies. 

This goal represents a major strategic change in the ORD’s Clean Air Research program. It 

envisions an approach to air pollution research that attacks the problem from a multi-pollutant 

perspective, encompassing all aspects of air pollution from source to health outcomes. It brings 

together three themes that are complementary and support one another and yet relate and expand 

the two themes comprising LTG 1 (Figure 5). Following the two themes of LTG 1, the themes of 

LTG 2 include: 3) launch a multi-pollutant research program to better reflect the nature of real 

world air pollution; 4) develop a source to health outcome approach to more effectively address 

air contamination, starting with the near-road issue; and 5) develop a framework for assessing 

the health and environmental impacts of EPA regulatory activities (i.e., accountability). For each 

theme, Table 3 aligns the APGs abbreviated as underlined phases within the narrative below. 

Implementing LTG-2 within the program promotes leveraging of ORD research activities to 

include under-funded goals within a broader framework, and more a logical orientation of the 

Clean Air Research program with the recent reorganization of our major client office, OAQPS. 

Theme 3: Develop a multi-pollutant approach to research 

Air pollution is a complex mixture comprising hundreds of primary emission products and 

secondarily transformed pollutants dispersed in ambient air. As such, in developing a multipollutant research activity to address associated risks, there must be consideration of the inherent 

toxicity of each constituent of the mixture, the likelihood of exposure to these constituents, and, 

even more challenging, the potential interactions among these constituents (which, in the end, 

may result from unique characteristics of toxicity or exposure because of these interactions). 

From a health perspective, noncancer effects are seemingly dominated by just a few pollutants 

(e.g., PM, ozone, CO, aldehydes) and, likewise, cancer effects involve specific classes of 

polycyclic organic compounds, and select metals and organic vapors. Indeed, PM is itself a 

complex mix with health impacts (both noncancer and cancer) that, to date, are best described as 

associated with PM mass. However, it remains difficult to attribute health effect observations 

completely to any single pollutant or class of compounds. Further, the evidence available to 

evaluate hazard and dose-response is highly variable among pollutants, with human evidence 

rarely available for the hazardous air pollutants whereas substantial human evidence is typically 

available for the criteria air pollutants, resulting in greater uncertainty in characterizing potential 

health risks from exposure to the HAPs. Additivity, antagonism, and potentiation have all been 

observed with air pollutant mixtures, but because the phenomena are poorly understood, 

regulation is, at present, best achieved by single pollutant regulations. 

Like PM itself, the chemistry of the general air pollution mix is more complex than the mere 

listing of the panoply of pollutants in ambient air. Many reactive gaseous and particulate 

components emanate from varied sources, which, through complex atmospheric chemistries, 

alter the atmospheric profile by consuming existent pollutants or creating new ones. Questions 

exist as to how PM as a complex mix in and of itself should be treated. Total mass is the default, 

28 
but as a measure composite mass is not necessarily robust across all health outcomes and end 

points. Hence, questions are raised relative to what is known about the toxicity of mixtures. Copollutants may interact chemically or may act through the exposed host altering his/her 

sensitivity; much remains unclear. If PM (as a collage of primary source emissions and 

secondary transformation products) and ozone (a gaseous product of atmospheric 

transformations) have the most impact on health outcomes, what might be the most effective 

strategy to minimize public health risk? Currently, measurement of PM only by mass regulates 

all contributors equally. In contrast, ozone is measured as a singular end product even though 

there are uncertainties remaining as to which source emissions are most significant in its 

formation. These enigmas beg the question, Can air pollution controls be better focused on 

sources from which the emissions are ultimately the most toxic? 

The challenge is to design a research paradigm to foster a logical and relevant transition from a 

single-pollutant research focus to a multi-pollutant approach, with the goal of controlling at the 

source to optimize health risk reductions. Initially, ORD must develop an integrated multiple 

pollutant research strategy (APG 16) that complements the goals and needs of ORD clients. 

Traditionally, systematic approaches to the assessment of pollutant mixtures have either started 

with a mixture and attempted to assess the driving components and/or interactions, or started 

with the component parts and built toward the mixture. Both approaches have merit and 

weaknesses and work best when used in a complementary, strategic manner. New “systems” 

approaches offer some guidance but, as yet, have had limited influence on the air pollution 

sciences. Part of any strategy, however, must involve deductive and inductive components. To 

the former, the Clean Air Research program will include multi-city/multi-pollutant studies (APG 

19) to establish a matrix of diverse source exposures from which component-driven health 

impacts might be discerned. Epidemiological and toxicological studies will determine whether 

adverse health outcomes are associated with the various exposure scenarios and PM sourcederived components. These data and findings can be compared with toxicology studies of 

defined laboratory source emissions, as well as controlled exposures to concentrated air 

particulates or other pollutants. Research will also be conducted to determine which sources and 

components humans are actually exposed to across cities. Integrating information from studies of 

specific sources and a hierarchy of associated toxicological potential, along with studies from 

cities with differing source profiles, will refine the assessment of risk and the criticality of 

pollutant type, character and source (integrated with findings from Theme 4). 

Theme 4: Identify specific source-to-health linkages, using “near-roadway” as the prototype 

Research clearly is needed to understand relationships among air pollutants (PM hazardous 

components, co-pollutants, and HAPs) emitted from emission sources and the resulting ambient 

concentrations and transformation products that may be involved in human exposures and 

adverse effects. ORD will develop analytic methods and enhance models/tools to link health (and 

where possible ecosystem) impacts to air pollution sources (APG 17). For example, methods to 

identify which pollutant sources contribute to exposures need further refinement for routine 

application to studies of health outcomes. Likewise, efforts need to be made to avail new 

information resources, such as satellite data, and to develop statistical techniques that can 

combine and integrate diverse data to improve ambient air quality and exposure estimates. This 

issue will grow in importance as more is learned on air quality-climate interactions. 

29 
As an initial focus for research on source-to-health linkages, ORD will address near-road 

emissions, exposures, and related health risks from mobiles sources and evaluate risk 

management options (APG 18). Near-road air pollution was selected as a central theme because 

it is a problem that is of pressing ORD partner interest/need; requires integrated, multidisciplined 

field and laboratory sciences; and allows the assessment the impacts of mitigation 

(accountability; see Theme 5 below). 

A growing number of health studies have identified adverse health effects, including respiratory 

disease, cancer, and even mortality, for populations living near major roads. These initial reports 

are raising concerns about the building of schools near roadways, the quality of indoor air in 

existing schools near roadways, and the general health impacts on people living near roads. A 

number of ongoing but somewhat disparate efforts regarding near-road environments already 

exist within the ORD portfolio. A more directed near-road pilot research effort has been initiated, 

with preliminary studies of near-road emissions, distance from road measurements, development 

of local environment dispersion models, and assessments of low-cost mitigation strategies for the 

indoor school environment. This research theme expands these efforts to determine the broader 

significance of near-road emissions from varied traffic, vehicles, and conditions; potentials for 

exposure and related health risks; and the development of tools for addressing the problem. 

Other research approaches will also be undertaken to systematically evaluate linking air pollution 

sources and components to health effects for specific sources (other than roadway) and single 

geographic locations (APG 20). Research projects will include toxicological studies of sourcespecific emissions, epidemiological studies in communities impacted by specific sources or 

industrial sectors, and health and exposure studies in specific geographic locations impacted by 

multiple sources. This approach dovetails with the multi-pollutant/multi-city studies underway or 

planned within Theme 3. Research also will address methods for evaluating risk management 

options in a multi-pollutant context. It is clear from existing research and the new sector-based 

approaches being adopted by OAQPS that controls at the source targeting certain specified 

pollutants typically reduce other emission components, many of which are also of concern. 

Theme 5: Assess health and environmental improvements due to past regulatory actions

Assessing the effectiveness or impact of regulatory decisions (often referred to as 

“accountability”) on exposure and health is a complex and challenging undertaking. When a new 

environmental regulation is issued, the changes necessary to achieve the regulatory objective of 

improved public or environmental health are generally not instantaneous, so there is rarely a step 

change in the outcome. Development of implementation plans, promotion and adoption of new 

technologies or management strategies, and other activities all take place over an extended time 

period. Even with the phase-out of lead from auto fuels in the 1970’s, the reductions in exposures 

and blood lead levels were not immediate, and even today vestigial lead (some from still 

uncontrolled sources such as piston aircraft fuels) and re-entrainment from deposition sites 

remain. During an implementation period, especially if extended over time, exposure and health 

also may be affected by other factors such as changes health care practices, changes in lifestyle 

(e.g., diet, smoking, obesity trends), or other changes resulting from regulatory or market forces. 

Research is underway to develop methodologies that can address the complexities of assessing 

30 
regulatory impacts. Several recent studies (intramural and from HEI) have suggested the 

feasibility of such assessments. 

As part of this research program, ORD intends initially to develop a framework for 

accountability studies (APG 15). This in-house effort will be coordinated with related work 

underway through HEI. A broader based accountability framework is being conceptualized 

across ORD (centered in the HHRP), in which the Clean Air Research program effort is being 

highlighted as a prototype because considerable thought and effort has been applied in concert 

with OAQPS. As currently conceptualized, the Air accountability framework will provide 

methods and examples for assessing the benefits and impacts of regulatory or other mitigation 

activities. Initial efforts are underway to evaluate existing and emerging databases for potential 

use, and prototypic models will be proposed for refinement and testing. ORD will be conducting 

field studies to evaluate whether control technologies are achieving anticipated pollutant 

reductions or resulting in unintended health and environmental consequences (APG21). Also, 

ORD will coordinate with efforts initiated by other organizations with similar interests (e.g., 

NARSTO, which currently is developing an assessment document focusing on accountability in 

air quality). By 2012, ORD plans to refine the Air framework and report on studies (intramural 

and extramural partners) assessing the impact of actions taken to reduce air pollution (APG 22). 

Table 3. APGs and APMs for LTG 2 

APG/APM Title Year 

Due 

Lead Lab 

APG 15 Develop a framework to assess the effectiveness of air pollution 

regulations and control strategies in reducing human exposure, 

ecosystem deposition, environmental and health impacts 

2009 NERL 

APM 69 Produce a conceptual Air Accountability Framework, including best 

available indicators and linkage techniques 

2009 NERL 

APM 70 Develop a mesoscale pilot of approaches for identifying and tracking 

regulatory impacts 

2009 NERL 

APM 71 As a principal sponsor and contributing author, report on NARSTO 

Accountability Science Assessment 

2009 NERL 

APM 72 Report on studies assessing changes in air quality and health status 

from actions taken to reduce air pollution 

2009 NCER 

APG 16 Develop an integrated multiple pollutant research program (MPP) 

strategy 

2009 NPD 

APM 73 Multi-disciplinary workshop on developing a multi-pollutant research 

program 

2008 NPD 

NHEERL 

APM 74 Develop air multi-pollutant strategy 2009 NPD 

APG 17 Develop methods and enhance tools to link health and 

ecosystem impacts to air pollution sources, including remote 

sensing and data combination techniques. 

2010 NERL 

APM 75 Develop and evaluate data combination techniques to improve human 

and ecological exposure assessments. 

2010 NERL 

APM 76 Identify new biomarkers of exposure or effect related to air pollution 

components or sources 

2010 NHEERL 

APM 77 Develop methods that provide more temporally and compositionally 

refined measurements of air pollutants that can be used to improve 

source apportionment analyses. 

2010 NERL 

NCER 

APM 78 Develop, improve, and evaluate advanced measurement techniques 

for SA of organic PM 

2009 NCER 

NRMRL 

31 
APG/APM Title Year Lead Lab 

Due 

APG 18 Determine the significance of near-road emissions/exposures 

and related health risks from mobile sources and evaluate risk 

management options 

2012 ORD 

APM 79 Characterize “combustion-related emissions and components 

(including volatile compounds)” and relate them to exposures and 

health effects in near-roadway environments 

2012 NRMRL 

NERL 

NHEERL 

NCER 

APM 80 Characterize how “mechanically-generated emissions” (including 

urban coarse mode particles) relate exposures and health effects and 

determine their relative toxicity in near-roadway environments. 

 NHEERL 

NERL 

APM 81 Determine how specific school mitigation approaches influence 

concentrations and exposures to near-roadway pollutants. 

2012 NRMRL 

NERL 

APM 82 Evaluate and identify assessment tools to aid urban planners in 

considering near-roadway health effects. 

2012 NERL 

APM 83 Provide information on the health effects and potential underlying 

mechanisms associated with exposure to diesel exhaust particles 

2010 NCER 

APG 19 Conduct multi-pollutant, multi-city studies to evaluate the relative 

associations of PM, components/sources of the mixture, and 

gaseous co-pollutants, with key human health events in multiple 

U.S. cities 

2012 NCER 

APM 84 Compile and analyze data on PM components from the speciation 

trends monitoring network 

2010 NCER 

APM 85 Strengthen national air monitoring databases for use in health studies 2011 NCER 

APM 86 Compare health risks associated with PM components, sources and 

co-pollutants from locations across the U.S. 

2012 NCER 

APG 20 Investigate relationships between sources, exposures, and health 

effects using a variety of approaches that focus on single 

geographic locations or specific sources (other than roadway) 

and identify options to reduce exposures for sources of concern 

2012 ORD 

APM 87 Apply source apportionment and exposure tools to support health 

studies investigating effects associated with specific geographic 

locations 

2012 NERL 

NCER 

APM 88 Characterize susceptibility and health effects resulting from selected 

sources of air pollution (other than roadway) and assess their relative 

toxicity 

2012 NHEERL 

NCER 

APM 89 Develop prototype model for evaluating integrated multi-pollutant 

emissions reduction approaches for U.S. industrial sectors and provide 

information on emissions and risk management options for key 

sectors. 

2009 NRMRL 

APM 90 Provide test methods and protocols for the indoor environment to 

assess proposed standards for aldehyde emissions and other air 

toxics from composite wood products 

2010 NRMRL 

APG 21 Evaluate whether control technologies deployed for major 

stationary and mobile sources are achieving the pollutant 

reductions anticipated and whether these technologies are 

having any unintended health and environmental consequences 

2012 NRMRL 

APM 91 Evaluation of existing data to determine the national-level performance 

of control measures implemented under major EPA rules 

2012 NRMRL 

APM 92 Evaluate control measures for possible adverse unintended 

consequences that impact human health and the environment 

2012 NRMRL 

32 
APG/APM Title Year Lead Lab 

Due 

APM 93 Describe health effects or toxic properties of manufactured 

nanoparticles intended for commercial use, pollution control, efficient 

energy use, or applications to modify air pollutants regulated by the 

Clean Air Act 

2012 NHEERL 

APG 22 Refine the Air Accountability Framework through the use of pilot 

or test-bed activities or related environmental opportunities for 

proof of concept. 

2012 NERL 

APM 94 Evaluate the progress assessment capability of the Air Accountability 

Framework and incorporate improved indicators and linkage 

techniques in an updated version 

2012 NERL 

APM 95 Develop and apply prototype methods identifying and tracking the 

regulatory impacts of CAIR 

2012 NERL 

APM 96 Report on studies assessing the impact of actions taken to reduce air 

pollution 

2012 NCER 

D. Linking Clean Air Research with other ORD Programs 

The Clean Air Research program coordinates with other ORD programs to achieve the best 

science and maximal leveraging of resources. The programs with which the Clean Air Research 

program coordinates most closely include HHRP, HHRA, the Global Change Research program 

(GCRP), the Mercury Research program, and the Ecological Research Program (ERP). The level 

of program coordination varies considerably. Involvement ranges from that in strategic planning 

and MYP development to coordination of specific program or research elements at the L/C level 

where leveraged research activities might lead to more broadly applicable results and data. 

Asthma exacerbation is an important issue to both the Clean Air Research program and HHRP. 

The Clean Air Research program supports asthma research within its susceptibility theme 

because the primary target organ system for air pollution is the lung and because of the clear 

predisposition of asthmatics to exaggerated responsiveness to inhaled toxicants. Asthma research 

is coordinated across both the Clean Air Research program and HHRP through coordinated 

APGs and APMs, project funding activities, and a local invited speaker series. Research being 

conducted to address asthma issues frequently involves humans and animal models exposed to 

various air contaminants (e.g., PM, ozone, HAPs, molds – all of interest to OAR clients). These 

studies provide data to assess susceptibility and basic modes of action that aid in extrapolation 

and risk avoidance recommendations for at-risk groups. Co-sponsored exposure research has also 

been applied to ambient pollutant environments to develop various receptor models used by risk 

assessors. In that spirit, the Clean Air Research program and HHRP recently cosponsored an 

intramural RFA to integrate the science and promote research coordination among asthma and 

other related indoor air research activities. In addition, the programs have leveraged support to 

studies assessing the health and environmental improvements resulting from past regulatory 

actions. 

The Clean Air Research program is linked to the HHRA program as both collaborator and as a 

provider of information and support. As the HHRA program, located within NCEA, is charged 

33 
with the responsibility of developing the NAAQS Integrated Science Assessments and IRIS for 

the HAPs, they are dependent on the science information produced by the Clean Air Research 

program for inclusion into their documents and assessments. The Clean Air Research program 

has historically been the primary source of the NAAQS database and continues in that role. The 

HAPs contributions to the HHRA program has been less substantive and limited to doseresponse model development for selected chemicals and toxicology information derived from 

mixture studies that include related HAPs. The Clean Air Research program also serves as an 

essential collaborator in document and workshop development and in the pursuit of core research 

underlying risk assessment methods (e.g., pulmonary dosimetry models, mode of action models, 

etc.). In their position as client, NCEA participates in the Clean Air RCT in setting priorities; 

likewise NCEA functions within the Assistant Laboratory/Center Director advisory group to the 

NPD in decision making and to ensure communication. The collaborative relationship between 

these programs is long-standing and is a strength of ORD’s overall air pollution research efforts. 

Atmospheric mercury is clearly an issue of concern to the Clean Air Research program. At 

present, this program is distinct from the Clean Air Research program because of unique EPA 

interests. Nevertheless, although the size of the program is relatively small when compared to 

Clean Air Research, actual mercury project planning and implementation are coordinated 

through Clean Air Research-funded program areas because many of the analytical and modeling 

tools overlap or are utilized similarly. Examples include specific coordinated projects to address 

targeted questions regarding control technologies (e.g., the use of selective catalytic reduction), 

and projects to monitor and assess mercury deposition and speciation in selected sensitive 

environmental areas. 

The Clean Air Research program historically has coordinated with the GCRP to better quantify 

and understand factors that may have impacts on global climate and air quality. The recent U.S. 

Supreme Court decision (No. 05–1120; Massachusetts et al. v. EPA)14 judged that EPA has the 

authority to assess the “greenhouse gas” CO2 as an air pollutant. As such, EPA has initiated a 

series of steps to evaluate CO2 from automobiles regarding potential “endangerment” to public 

health and the environment. The Court’s decision and subsequent activities on the part of EPA 

forecasts changes in the assessment and potential regulation of CO2, which likely will have 

implications regarding research in both the Global Change and Clean Air Research programs. 

Expanded research and program integration is possible. However, interactions have been 

ongoing. One example is research on emissions of elemental carbon, which recent evidence 

shows may have important implications for climate change because of its ability to absorb solar 

radiation. Other interactions involve the development of atmospheric models (such as CMAQ) 

and climate models, which are now advancing to sufficient sophistication to begin to address 

questions of air quality impacts on climate and vice versa. Tools are also under development to 

evaluate future technology change and how this could impact future levels of CO2 and other air 

pollutants of concern. The goal of this research is not only to assess these cross-impacts of air 

quality and climate but to provide predictive tools for guidance to the policy directors and for 

public communication (e.g., AIRNow). This portion of the program may well see substantial 

change in the future. 

Current coordination with the ERP is limited. Shifting program priorities and fiscal constraints 

 

14 Decision: http://www.supremecourtus.gov/opinions/06pdf/05-1120.pdf. 

34 
have taken the programs in somewhat separate directions over the past several years. However, 

with recent changes in the ERP toward an “ecosystem services” focus, which relates more to 

issues associated with the air-ecosystem interface, it is anticipated that common research areas 

and activities will be identified for collaboration. Already in 2006-2007, the Clean Air Research 

program funded a pilot in ecosystems assessment to examine sulfur deposition profiles and the 

distribution of local acidification, in part as an accountability effort. Currently, the ERP is 

undergoing major revision, and these coordination issues will be addressed more fully in future 

MYP revisions. 

E. Performance Assessment Rating Tool Long-Term Goals and Measures 

Protection of public health and the environment from the adverse impacts of air pollution is the 

ultimate goal of ORD’s Clean Air Research program. Achieving this goal is neither easy nor 

straightforward, given the complexity of anthropogenic and natural emissions and the potential 

for human health impacts. Lying between emissions and health impacts is a complicated array of 

atmospheric physicochemical processes and myriad human biological and behavioral factors that 

affect exposure and response to and recovery from environmental stressors. OMB utilizes the 

Performance Assessment Rating Tool (PART) as a means to periodically evaluate the progress 

and efficiency of the Clean Air Research program in its efforts to achieve the goals of improved 

air quality and reduced risk. The mission of PART is to establish clear measures and milestones 

against which the program can be monitored and assessed regarding overall stewardship of the 

public trust and progress toward outcomes that demonstrate or reflect benefit to the American 

public. 

The MYP is constructed around two LTGs toward which progress can be evaluated. Structured 

under these goals are the APGs and APMs that provide products or building blocks, which, if 

accomplished or achieved in a timely and efficient manner, can be used as one tool to evaluate 

program progress and effectiveness. PART is clear on its distinction between program 

“products” and “outcomes.” In effect, although products (research findings, models, and tools) 

are important to the science and the program, it is progress towards the outcome (public benefit) 

that is most important. Table 4 lists the long-term and annual measures being used to assess the 

Clean Air Research program. 

35 
Table 4. PART Measures 

Measure Type of Measure Measure Language 

Long-Term Outcome Progress in assessing the linkage between health impacts and air 

pollutant sources and reducing the uncertainties that impede the 

understanding and usefulness of these linkages 

Long-Term Outcome Progress toward reducing uncertainty in the science that supports the 

standard-setting and air quality management decisions 

Long-Term Output Percentage of program outputs appearing in the Office of Air and 

Radiation's National Ambient Air Quality Risk and Exposure 

Assessment 

Annual Outcome Percent improvement in customer satisfaction and product 

usefulness survey score 

Annual Output Percent progress toward completion of a hierarchy of air pollutant 

sources based on the risk they pose to human health 

Annual Output Percentage of program publications rated as highly cited papers 

Annual Output Percent of planned actions accomplished toward the long-term goal 

of reducing uncertainty in the science that supports the standardsetting and air quality management decisions 

The Clean Air Research program must report to OMB PART its accomplishments as measured 

against the annual and long-term goals, and every 4-5 years the Clean Air Research program 

must undergo a full PART review to assess its long-term effectiveness. ORD has also developed 

Program Improvement Plans that identify specific actions to be taken to improve performance. 

For the Clean Air Research program, these include: 

• Convene annual program reviews in which extramural expert discipline scientists and 

clients will assess the state of ORD science, ensure progress toward outcome goals, and 

determine the need for strategic mid-course adjustments to maximize program efficiency 

and assist with out-year planning. 

• The program must develop at least one efficiency measure that adequately reflects the 

efficiency of the program. 

• Improve multi-year plan (MYP) and financial data tracking systems and procedures to 

better and more transparently integrate grantee and program performance with financial 

information. 

• Develop an annual measure that more directly demonstrates progress on toward the longterm goal of reducing uncertainty in identified research areas of high priority. 

• Develop and implement adequate methods for determining progress on the program's two 

new long-term measures (uncertainty and source-to-health linkage measures) as well as 

for the new annual measure (customer survey measure). 

For each of these elements, some action has been taken, but the overall goal has not been 

completed. 

36 
III. CONCLUSIONS 

A. The Clean Air Research program supports OAR and other client-partners. 

The Clean Air Research program provides critical science to science-users (i.e., NCEA, OAR) to 

establish or refine the underpinnings of important regulatory decisions and public guidance. The 

program also provides the tools and models along with the technical support needed to 

implement these decisions in the field. These contributions derive from a science and 

engineering platform that is regarded, both within EPA and internationally, as integrated and 

high performing. Although the science has shown individual air pollutants have effects on health 

and welfare, mixtures of air pollutants truer to the realities of ambient air have the potential to 

interact in complex ways potentially altering its outcomes. As protection of public health is a 

primary EPA goal, minimizing health impacts may be more effectively achieved by strategic 

control of sources that contribute directly or indirectly to health outcomes. The potential value of 

multi-pollutant approaches has been recognized by OAQPS in its organizational structure and 

planning and as such, the timing is appropriate for the Clean Air Research program to make a 

science investment in this area. ORD will formulate its multi-pollutant research program from a 

source-to-health outcome paradigm. This paradigm is implicitly cross-discipline and integrated 

and, as such, provides opportunities for more effective control strategies and positive impacts on 

health. 

B. Air research will evolve as a multi-disciplined, integrated endeavor founded upon the NRC 

Priorities for PM as it builds upon the source-to-health outcome paradigm. 

The current MYP lays out a strategy that serves the current regulatory mandate of EPA and 

begins to move air pollution sciences that support regulatory decision-making to a more realistic, 

yet more complex, multi-pollutant paradigm. The three historic Air research themes are now 

organized into one Air program (Clean Air Research), although the impact return for PM 

research supports it as a primary program focus. The NRC priorities have been invaluable in 

organizing the PM research over the last decade and, as an approach, have been central in the 

prioritization of the multiple needs of Clean Air Research program clients. It is clear that these 

commitments to the NRC issues have been structured into the APGs and APMs as they relate to 

PM, including assessments of hazardous components, particle size, effects of long-term 

exposures, susceptibility, mechanisms, exposure assessments, atmospheric sciences, 

implementation model and tool development, emissions and controls, etc. What has evolved is 

the program vision to also undertake the challenge to link pollutant sources to their ultimate 

health outcomes within a multi-pollutant construct. This construct will continue to evolve as the 

MYP is implemented, and it will have multiple inputs from OAQPS as it develops its multipollutant policy test beds, NARSTO as it finalizes its assessment of multipollutant/accountability assessment document, and other client feedback. The near-road sourceenvironment has been established as the MYP prototype for implementing this paradigm. The 

goal is better targeted and more efficient control and mitigation and improved public and 

environmental health. 

C. Future research issues are already emerging as current regulations, land use, 

transportation, and climate change impact both local and regional air quality. 

The Clean Air Research program is well positioned to address emerging air quality issues. 

Adopting a multi-pollutant future, changes in regulation (CO2 impacts and controls) and climate37 
air quality interactions at the local and regional scales are already under study by ORD. 

Intramural workgroups and STAR-supported projects (current awardees and planned RFAs) 

provide the foundation for expanded research as this issue evolves over the next few years. 

38 
Appendix A: Recent Program Accomplishments 

ORD’s Clean Air Research has a long history of responsiveness to client priorities, and 

delivering relevant and useful products that support decision-making and policy implementation. 

The report, “Particulate Matter Research Program: Five Years of Progress” (February 2004; 

referenced in footnote 8) summarizes notable PM-related achievements of the research program 

from 1998, when PM became prominent issue, through 2002. That report was organized around 

the 10 priorities noted earlier by the NRC (see footnote 5); a revised and updated ORD progress 

report is scheduled for release in 2009. In this appendix, selected achievements since 2005 are 

highlighted. This summary is not intended to be a complete overview but rather to provide 

insight into program value. Since 2005, the Clean Air Research program has built on its previous 

successes, with the goals of refining our understanding of the science necessary to reduce 

uncertainties in decision-making and improving the tools needed to assess and implement policy. 

The key to these advances lies in interdisciplinary science and integrated program execution. 

This section will cite selected achievements from across the entire program, not just PM. 

Because the Clean Air Research program is moving forward to a multi-pollutant framework, this 

accomplishments overview is presented using the core paradigm shown below. 

Source →Atmospheric Transformation →Exposure →Dose →Health Outcome

Source 

Emission characterization of prime sources contributing directly or indirectly to air pollution is 

fundamental to the value of the source-to-health outcome paradigm. Not only does it serve to 

reduce uncertainty in the development and implementation of effective mitigation or control 

strategies, emission characterization serves to link health risks to gaseous or particulate 

components, as well as to sources, with greater specificity. This goal was noted as high priority 

by both NRC panels (Priorities and Air Quality; see page 3, footnote 5) and as fundamental to 

integrated air quality assessments and to the development of appropriately targeted health-based 

standards. In this regard, significant advances in updating and improving emission inventories 

have been achieved on multiple fronts. Those sources pursued by ORD are generally not those 

assessed by State regulatory units but are more generic and poorly characterized. For example, 

diffuse sources are particularly problematic. Advancements in optical remote technologies have 

yielded new data from varying types of biomass burning to livestock waste ponds. Optical 

remote methods for precursor gases such as ammonia are not only important for general air 

hygiene but allow refinements in atmospheric models where ammonia is a major assumption in 

aerosol chemistry (e.g., acidity). Similarly, laser-based, time-of-flight instruments provide realtime analyses of trace organics, including aromatics and PAHs, in dilute vehicle exhaust and 

fugitive emissions. Engine emission characterizations from various vehicle types, such as idling 

versus moving diesel school buses, have likewise undergone detailed study not only of mass 

emissions but chemical speciation. Other sources heretofore not well characterized in the context 

of their relative impact on ambient air, ranging from dispersed seasonal wildfires to point sources 

such as airports, have begun to be characterized using analogous advanced optical and prototype 

satellite-based technologies. 

39 
Collectively, these data improve and update emission inventory databases maintained by EPA 

(e.g., SPECIATE) on which comprehensive atmospheric models used in OAR and 

State/Region/tribe implementation strategies (e.g., SIPs) depend. Advances in mobile source 

emission characterization also serve on the science investigatory front mainly in the area of 

sensitivity and response-time (e.g., deep UV differential optical absorption spectrometry – DUV 

DOAS) and, as such, will be important in the developing near road research program. 

Advances in control technologies have demonstrated effective reductions and removal of NOx 

(most importantly NO2) and mercury (Hg0

) from pilot plant coal-fired boilers. Refinements in 

these technologies are critical as coal combustion grows nationally. These same pilot plant 

operations have also been used for comparative emission toxicology studies and assessments of 

physical and compositional attributes of PM emissions. Analogous diesel studies have revealed 

significant compositional and toxicity variance. Real-world animal exposures to traffic emissions 

(diesel and gasoline) have shown varying effects (from pulmonary to neurological) likely 

because of varying concentration profiles and aging related changes in gases and particles. In 

general, proximity to the roadway has yielded the most consistent responses. Across ORD 

(intramural and extramural) there is increasing focus on source-based responses to ascertain 

hierarchical toxicity patterns and compositional relationships. 

Atmospheric Transformation 

Once pollutants are emitted, it is important to understand how they interact with other 

compounds present in the ambient environment. These transformations and interactions are 

critical inputs for our air quality models and directly impact the types and concentrations of 

pollutants the population is exposed to over time. Laboratory and field studies have made 

substantial gains in our defining atmospheric chemistries that play significant roles not only to 

achieve a better understanding of theses processes in ambient air but in refining the predictive 

accuracy of complex multipollutant atmospheric models like CMAQ. Each year, one or more 

upgrades of CMAQ is released for client as well as research use with the next major revision for 

SIP development due in 2008. ORD investigators have refined or overhauled chemistry modules 

that drive components of the model (e.g., photochemistry of mobile-source-derived aromatics). 

Similarly, other studies have been able to discriminate dominant biogenic hydrocarbons from 

other organics as critical drivers in ambient photochemistry. These refinements have advanced 

our understanding of carbon, nitrogen, sulfur, and even mercury chemistries in CMAQ and 

related but more specialized atmospheric models. The upgraded models are tested and validated 

against real-world temporal and spatial measurements before release. Also, the CMAQ model 

now has, for the first time, incorporated a new weather research and forecasting (WRF) 

meteorological model that will be the foundation of future air pollution and climate predictive 

models. As these models are multipollutant and are widely run for SIP development, ongoing 

refinements, especially in the highly complex organic arena, have been critical to accuracy and 

dissecting the relative prominence of the anthropogenic and biogenic (e.g., natural terpenes, 

isoprene, etc.) contributions. With the growing use of ethanol and biofuels as alternative fuels 

and the introduction of new additives with various functions, predictive models suggest changes 

in atmospheric chemistry that may alter transformation product profiles. 

Atmospheric models, such as CMAQ, are being asked to refine to smaller area grid sizes for 

community application, to continually broaden the pollutant mix (e.g., HAPs have now been 

40 
incorporated), and to attempt to tie to dispersion models in an effort to find innovative 

approaches to couple with personal exposure models and, ultimately, health effect studies. 

Intramural work is ongoing in collaboration with OAR and the STAR program scientists and 

NCER-STAR has released an RFA to further develop these innovations. Linking across models 

and data to achieve better risk estimates and provide predictive information that may be 

amenable to AIRNow-like public broadcasting is an important goal of EPA.

Exposure 

There have been marked gains in refining links between regional and local exposure metrics with 

those that relate to personal exposures for PM and some of its attributes (most notably size). 

Admittedly, less has been gained regarding co-pollutant exposures, although there are improved 

exposure measures for some HAP compounds. In the case of PM, comprehensive field studies 

have been conducted to evaluate the performance of sampling methods for measuring the coarse 

fraction of PM10 in ambient air. These have been conducted in several venues across the United 

States as part of the Federal Reference Method (FRM) development project. This FRM is 

complete and is being deployed by states. At the other end of the size spectrum, recent concerns 

regarding traffic exposures have prompted exposure profiles for ultrafine PM emissions relative 

to distance from roadways. There now exist some measures that tie to freeways, traffic volume 

and vehicle type. ORD has particular interest in the effect of various mitigation methods, 

especially as they relate to indoor penetration values. Building type and ventilation appear to be 

major factors in penetration of ultrafine and coarse mode PM, as well as oxidant gases, but 

appear to be less significant (on a relative basis) for fine PM and less reactive gases. Individuals 

considered “susceptible” because of age or pre-existing disease appear to have exposure profiles 

similar to those without susceptibility risk factors, with central monitors appearing to provide 

reasonable estimates of fine PM exposure for the associated population. Not inconsistent with 

this evidence for refined exposure metrics, a recent study in Los Angeles has demonstrated that 

increasing the areal density of monitoring can reveal neighborhood-by-neighborhood differences 

in health outcomes. These findings suggest greater PM risks than previously appreciated with 

regional monitors. On the other hand, this was not clear in New York City, leaving this 

provocative question to be further explored. 

A large, multiyear, multi-season exposure study conducted in Detroit has completed its data 

collection (winter 2007) which is being compiled into databases for estimation of sourceattributable exposures, regionally, locally, and indoors across the Detroit urban landscape. New 

speciation methodologies for organics have been developed and are yielding data refining PM2.5

composition and its source links. These advancements should help refine existing receptor (e.g., 

SHEDS) and source apportionment models (e.g., UnMix) now in wide use but that have large 

uncertainties. Related intramural and leveraged health studies in asthmatic children and adults 

with cardiovascular disease in the Detroit area will yield refined risk estimates and better source 

attribution. As noted above, when coupled with the concept of developing linkages with 

atmospheric and receptor models that can track to the human effect level, clients will be able to 

better assess the impact of source-oriented mitigation strategies. 

41 
Dose 

Exposure estimates are inherently inaccurate biometrics for human dose. Variation in dose from 

individual to individual is often responsible for perceived biologic variability. Comparative 

dosimetry is also important in linking the toxicological databases from animal toxicology to the 

human condition. Dosimetry, when coupled with biological differences (e.g., species, preexisting disease, age) and variable exposure scenarios (e.g., exercise, lifestyle, co-exposures), 

contributes to the uncertainties in final risk assessments. New findings with PM size modes in 

subjects with lung disease augment what has long been known in healthy individuals – that PM 

size is the major determinant to deposition profiles in the respiratory tract. Fine PM penetrates 

more deeply into the lung than coarse PM but recent human data shows that although ultrafine 

PM deposits penetrate the lung in large numbers per given mass, the deposition pattern in a 

within the lung was not unlike that of coarse PM. In other words, large numbers (and more 

relative mass) of ultrafine PM deposit in the airways and, therefore, ultrafine PM should not be 

considered a risk only for the deep lung. With regard to fine and coarse PM, but less so with 

ultrafines, individuals with airway disease show increasing heterogeneity in deposition with 

evidence of “hot spots” at airway bifurcations. Locally high doses of PM to lung tissues may 

result and may determine the degree of damage to that region and may well account for the 

exacerbation of responses (because of the higher dose) noted in people and animal models with 

pre-existing lung diseases (e.g., asthma, COPD). 

There is also related evidence that solubilized components of fine PM (e.g., metals and polar 

organic compounds) permeate through the lung and distribute systemically, perhaps impacting 

the cardiovascular and other organ systems. Ultrafine particles, associated with combustion 

processes, may themselves also penetrate through lung tissues and move systemically by evading 

normal defense systems that remove larger particles from the lung surface. Given the concerns of 

traffic exposure and the predominant ultrafine PM profile near roadways, associations of health 

outcomes with traffic have been linked hypothetically to ultrafines, although research on copollutants and other road products continues. Studies also show that various organic compounds 

(through adsorption) associate with PM and can be transported deep into the lung. Once 

disassociated from the particles, these materials can act locally or distribute systemically within 

the exposed organism. Thus, health outcomes may reflect the inherent toxicities of particles and 

their co-associated materials. 

Health Outcome

ORD-supported research has established the backbone of our understanding of air pollution 

health outcomes. In the PM arena, specifically, more than 40% of the research citations in the 

Criteria Document (called the Integrated Science Assessment for the NAAQS currently under 

review) and the Staff Paper (now called the Policy Assessment in rule decision-making) were 

ORD-supported products. Currently, PM maintains its distinction as that air pollutant most 

widely considered to pose a significant and widespread public health threat. A spectrum of 

epidemiological studies, including various observational and panel studies, show relatively 

consistent risk estimates for mortality in around the country, especially with regard to pulmonary 

and cardiac health impacts. Morbidity, as reflected in a wide range of end points or responses 

(e.g., hospitalization, school absenteeism) also relates to PM. An ever increasing group of 

outcomes now associate with PM, and in some better still when combined in analyses with its 

co-pollutants – infection, lung growth retardation, infant birth weigh and cardiac structure. 

42 
Cardiovascular-related mortality in adults, however, appears to be strongly related to PM 

exposure, both in terms of acute mortality risk as shown in a large study of older women as well 

in the general population. Additionally, a study of Medicare data for 11.5 million people living in 

204 urban counties in the United States found region-specific differences between the eastern 

and western halves of the country when assessing hospital admission rates for cardiovascular and 

respiratory diseases. In the Northeast, cardiovascular dysfunction can be related temporally to 

PM exposures even within a few of the day. Interestingly, however, the Northwest, which is 

dominated by wood smoke emissions in the winter, did not show straightforward links between 

PM mass and cardiovascular events. As such, it appears that not all sources have similar impacts 

on cardiovascular functions. As already noted, refinement of spatial exposure metrics through 

more densely distributed monitors led to the discrimination of neighborhood-to-neighborhood 

differences in PM mortality in Los Angeles. It also appears that reductions in major industrial 

sources that contribute substantially to local and regional PM levels result in reductions in 

mortality and morbidity. Hence, sources do appear to vary in their potencies, and it may well be 

the mixtures (PM components and with co-pollutants) that drive the differences in response. 

Collectively, the epidemiological findings are ever more strongly suggesting that there exist 

significant susceptibility factors in responses, including age (perhaps linked to greater 

exposures), syndrome complicated with cardiopulmonary impairments (e.g., diabetes), asthma 

(notably in children), and COPD or heart disease (especially in the elderly with congestive heart 

failure), as well as in selected genotypes. In the last case, the ability to withstand oxidant 

challenge may well be a survival factor, and those lacking certain genes (e.g., GST-M1) may 

have impaired antioxidant or related defenses. On the other hand, real-world exposures to 

healthy highway patrol officers suggest that components of complex roadway emissions (gases 

and particles, including metals) also show evidence of cardiac dysfunction. 

Animal studies show analogous patterns of response and susceptibility, and strongly suggest that 

oxidative stress plays a role in the toxicity of PM. A role for oxidant pathways is largely borne 

out in in vitro studies. Markers of oxidant stress appear to tie to progression of diseases (e.g., 

atherosclerosis) in rodent models exposed to various PM (concentrated ambient particles [CAPs] 

and combustion emissions). Cardiac dysfunction in diseased animals has been seen with roadway 

emissions (mainly ultrafine) and combustion particles enriched with metals. Studies of CAPs in 

humans and animals show a more variable pattern of cardiac responses that do not always 

parallel the panel studies suggesting that the complexities of exposure (e.g., a role for copollutants) and biologic scenarios are important modifiers of response. Hence, although there 

appears to be credible evidence of health effects associated with PM, these are difficult to fully 

reproduce under controlled conditions, perhaps because of the lack of co-pollutant interactions. 

Similarly, compositional correlates are not always discernable. The likely involvement of 

multiple components in varied adverse health outcomes argues that the most effective means of 

study and control will emerge from source-oriented analyses. What does seem consistent from 

collective assessment is a likely critical role for oxidant stress, perhaps at various levels of organ 

and cellular bio-pathways, and that individual variability arises, at least in part, from 

susceptibility (inclusive of dose, frailty, and genetic determinants that may impart adequate 

defense). 

43 
44