January 28, 1999

EPA-SAB-CASAC-ADV-99-002

Honorable Carol M. Browner

Administrator

U.S. Environmental Protection Agency

401 M Street SW

Washington, DC 20460

Subject: Clean Air Scientific Advisory Committee (CASAC) Advisory on the PM2.5

Monitoring Program

Dear Ms. Browner:

The Clean Air Scientific Advisory Committee (CASAC) of EPA’s Science Advisory

Board reconstituted its Technical Subcommittee on Fine Particle Monitoring (the

“Subcommittee”), at the Agency’s request, to provide advice and commentary on the Agency’s

fine particulate matter (PM2.5) monitoring program. The Subcommittee, chaired by Dr. Phil

Hopke of CASAC, met with Agency staff on November 30, 1998 for the first of what is

envisioned as a continuing series of discussions as the monitoring program is designed and

implemented. The attached Subcommittee report has been reviewed and approved by the full

CASAC.

The Subcommittee report conveys CASAC’s view that the most appropriate role for the

Subcommittee is to respond to questions posed by the Agency and provide additional advice and

commentary in a continuing, participatory, and pro-active manner. It also describes the working

relationship between CASAC and the NAS/NRC Committee on Research Priorities for Airborne

Particulate Matter. The optimal nature of this relationship has been discussed thoroughly among

and between the two groups, and relationship portrayed in the Subcommittee report represents a

consensus view.

The attached report summarizes the Subcommittee’s technical advice regarding two

specific issues posed by the Agency, and provides additional comments on related issues.

The CASAC is pleased to establish an interactive advisory relationship with the Agency

through this Subcommittee, and looks forward to assisting the Agency in optimizing the design

and implementation of its fine particle monitoring system and the utility of the information that

system will provide.

Sincerely,

/signed/

Dr. Joe L. Mauderly, Chair

Clean Air Scientific Advisory Committee
i

U.S. Environmental Protection Agency

Science Advisory Board

Clean Air Scientific Advisory Committee (CASAC)

Chair

Dr. Joe Mauderly, Director of External Affairs, Lovelace Respiratory Research Institute,

Albuquerque, NM

Members

Mr. John Elston, Administrator, Office of Air Quality Management, State of New Jersey,

Department of Environmental Protection and Energy, Trenton, NJ

Dr. Philip K. Hopke, Dean of the graduate School, and R.A. Plane Professor of Chemistry,

Clarkson University, Potsdam, NY

Dr. Eva J. Pell,, Steimer Professor of Agricultural Sciences, Pennsylvania State University,

University Park, PA

Dr. Arthur C. Upton, M.D., Director, Independent Peer Review, CRESP, Environmental and

Occupational Health Sciences Institute, Piscataway, NJ

Dr. Sverre Vedal, M.D., Professor of Medicine, University of British Columbia, Vancouver, BC,

Canada

Dr. Warren White, Senior Research Associate, Washington University, Chemistry Department, 

St. Louis, MO

Science Advisory Board Staff

Mr. Robert Flaak, Designated Federal Officer (DFO) and Team Leader, Committee Operations

Staff, US Environmental Protection Agency, Science Advisory Board, Washington, DC

Ms. Diana Pozun, Management Assistant, US Environmental Protection Agency, Science

Advisory Board, Washington, DC 
ii

NOTICE

This report has been written as a part of the activities of the Science Advisory Board, a

public advisory group providing extramural scientific information and advice to the Administrator

and other officials of the Environmental Protection Agency. The Board is structured to provide

balanced expert assessment of scientific matters related to problems faced by the Agency. This

report has not been reviewed for approval by the Agency; and hence, the contents of this report

do not necessarily represent the views and policies of the Environmental Protection Agency or

other agencies in the Federal government. Mention of trade names or commercial products does

not constitute a recommendation for use.
Report of the 

Clean Air Scientific Advisory Committee (CASAC )

Technical Subcommittee on Fine Particle Monitoring
January 27, 1999

Dr. Joe Mauderly, Chair

Clean Air Scientific Advisory Committee

U.S. Environmental Protection Agency

Washington, DC 20460

Subject: Advisory on the Agency’s PM2.5 Monitoring Program

Dear Dr. Mauderly:

The Technical Subcommittee on Fine Particle Monitoring (hereafter, the “Subcommittee”)

of the Clean Air Scientific Advisory Committee (CASAC) met in Research Triangle Park, NC on

November 30, 1998 at the request of the Agency’s Office of Air Quality Planning and Standards

(OAQPS). OAQPS requested that the Subcommittee provide advice and commentary on two

major components of the Agency’s PM2.5 Monitoring Program, namely, the chemical speciation

program, and the “supersites” program. The materials provided to the Subcommittee for review

are listed in Appendix A.

1. Background and Development of the Charge

In April 1996, this Subcommittee (with different membership) reviewed and commented

on the Agency’s Federal Reference Method (FRM) and guidance to the States on the location and

number of monitors (CASAC, 1996). Among the recommendations presented by the

Subcommittee were that national networks include measurements that go beyond the FRM, to

include chemical composition and continuous instruments. These measurements are embodied in

the two major components of the PM2.5 measurement program mentioned above.

In January 1998, the National Research Council (NRC) established its Committee on

Research Priorities for Airborne Particulate Matter. This Committee was established in response

to a request from Congress in the Fiscal 1998 appropriation to EPA, and is charged to identify the

most important research priorities relevant to setting particulate matter standards, to develop a

conceptual plan for particulate matter research, and, over five years, to monitor research progress

toward improved understanding of the relationship between particulate matter and public health. 

The Committee has issued one report to date (NRC, 1998) with a second due shortly. Three

members of the NRC Committee serve on the CASAC Subcommittee.

In May 1998, OAQPS obtained the advice of a Speciation Network Expert Panel on

EPA’s PM2.5 Chemical Speciation Network (item A-7 listed in Appendix A). The Chair of that

expert panel also serves on the CASAC Subcommittee to provide continuity and to convey

recommendations of the expert panel.
2

In the FY1999 VA-HUD and independent agencies appropriation bill that addresses the

roles of the National Academy of Sciences (NAS) and the CASAC in reviewing the PM

monitoring program (Cong. Record - House, H9428, October 5, 1998), Congress stated the

following:

...with respect to the speciation component of the Agency’s PM monitoring plan, the

conferees request that the NAS assist the EPA’s Clean Air Scientific Advisory Committee

(CASAC) by providing recommendations regarding the number and location of monitors

and specific objectives and operating conditions for the various types of speciation

monitors in EPA’s plan. Also, NAS should evaluate the adequacy of the speciation

component of the monitoring plan to characterize those constituents of PM that are

biologically active. The NAS is expected to facilitate a thorough peer review of the

speciation component of EPA’s monitoring plan by CASAC.

During its November 1998 public meeting (held under the provisions of the Federal

Advisory Committee Act), the Subcommittee was briefed by OAQPS staff on various aspects of

the monitoring program including regulatory time lines, components and objectives of the

program, implementation of the chemical speciation program, supersite concept plan, and PM2.5

data analysis plans. The Subcommittee also was briefed by the Office of Research and

Development (ORD) on the Agency’s PM research program and linkages with monitoring. The

Subcommittee also received public comments from the American Petroleum Institute (API) and

the National Stone Association (NSA).

The first area of discussion at the meeting was the development and refinement of the

charge to the Subcommittee. The highlights of that discussion are captured below. A formal

charge will be prepared based on these discussions and be available by the time of the next

Subcommittee meeting in the Spring of 1999.

2. General Discussion

a) Role of the Subcommittee - In order to facilitate communications between

CASAC and the NRC Committee on Research Priorities for Airborne Particulate

Matter, three of the NRC committee members are members of the Subcommittee. 

Discussions within the NRC committee have made it clear that they do not want

responsibility for providing advice or oversight of the PM monitoring program. 

Given the Congressional mandate to CASAC with respect to the speciation

network, it seems that CASAC will be the body with the major responsibility for

reviewing the science going into the PM monitoring networks. Thus, the

discussion focused on how the Subcommittee could facilitate this review. 

Among the materials presented to the Subcommittee, the Draft Supersites

Conceptual Plan outlined a management scheme proposed by the Agency for the

supersites program (see Figure 1). This scheme stimulated discussion in two areas. 
3

Data

Analysis

Field

Measurements Planning DataManagement

Quality

Assurance

Participating Research Groups and Contractors

Principal EPA Coordinators

OAR Designate

ORD designate(s)

Supersites Coordination Committee

(Sponsors (Supersites and relevant 

studies)) EPA (OAQPS, ORD); DOE; 

State/Locals; Industry

External research 

Coordination

CENR; NARSTO/HEI; 

NAS/CASAC EPA Steering Committee

EPA Staff (OAR, NERL, NHEERL)

Science Oversight

 Freq. 

NAS

FP Subcommittee

(CASAC)

Executive Leads

EPA OAR and ORD AA designates

Project Organization

Figure 1 - Project Management Overview (Taken from Figure 3 of the Draft Supersites Conceptual Plan

Nov. 9, 1998, pg. 7, November 9, 1998)

First, there was concern that although there was a clearly defined management

scheme for the supersites program, there are no comparable schemes for the

speciation and mass monitoring programs and no overall scheme that coordinates

the entire monitoring program. Although much of the speciation and mass

monitoring network will be implemented and operated by State and Local air

quality management organizations, there is still a need for coordination and

management at the national level. There are important interrelationships among 

the three parts of the monitoring program. A management scheme that provides

for communications and coordination throughout the program is essential if the

maximum information is to be derived. The Subcommittee thus suggests that the

Project Organization outlined in Figure 1 be expanded to become the Fine PM

Monitoring Program Organization.
4

The second concern was the need for continuing scientific input into the design

and implementation of the monitoring program. There are provisions in Figure 1

for Science Oversight and Research Coordination. However, the nature of the

group that will provide those functions is not yet defined. The NRC committee

has indicated that they do not envision their committee taking on this

responsibility. After discussion, it was unanimously agreed that the Subcommittee

would be willing to serve as the scientific advisory body to the PM monitoring

program. This role would require the Subcommittee to both react to materials

prepared by EPA as CASAC has traditionally done and to provide input to the

EPA management team as scientific information relevant to the monitoring

program becomes available. Thus, a more proactive role is envisioned for the

Subcommittee as the monitoring program evolves.

b) Responses to Specific Questions - There were two specific questions on which

EPA desired more immediate comments:

(1) Speciation network - One question concerned the proposed plan for the initial

establishment of 53 sites in the speciation network that would serve as the trends

network sites. The same type of sampler would be deployed at each of these sites

and all of the samples would be analyzed by a single laboratory. The specific

choice of sampler will be made at the end of the intercomparison study that will be

initiated over December 1998 and January 1999 in 4 cities across the United

States. The Subcommittee expressed concern about problems with the

intercomparison study being conducted only during the winter when the full effect

of temperature on semivolatile components of PM may not be observable. It is

highly recommended that additional studies be conducted during the summer,

particularly in the Eastern United States, although there is also concern about loss

of nitrate in California. In addition, it is not clear what criteria will be used to

judge the results of the intercomparison study and how they will result in the

selection of the sampler to be deployed at the Trends Network sites. It is likely

that differences will be observed in performance among the proposed speciation

samplers and substantial differences in some cases with the FRM. Because there is

no absolute “gold” standard for the true value of the concentration of condensed

material in the atmosphere, the Subcommittee recommends development of a set

of evaluation criteria before any of the results of the intercomparison study are

obtained. An objective evaluation with well defined criteria performed on the

results can lead to a choice of sampler that can be accepted by all involved in the

process. The Subcommittee agrees that the plans for the initial deployment of the

trends network samplers are as scientifically sound as possible given the time

constraint that precludes summer tests of proposed samplers, and that it is

reasonable for the Agency to move ahead to implement the plans as outlined

although there remain concerns that the samplers will not have been fully tested.
5

(2) Supersite Network - The second question involved the revised plans for

deployment of the supersite network. The plans now call for an initial deployment

at two sites, Fresno and Atlanta, with a subsequent phase-in of other sites at

locations to be determined as the plans for the PM research program develop. One

of the major uncertainties in locating additional sites is their possible relationship to

the new PM research centers that will be awarded during the first half of 1999. 

Thus, the limited deployment of two sites permits testing of systems, assessing of

the operational problems and costs of these systems, and developing better plans

for the remaining sites to produce the maximal information from these limited

number of supersites. The Subcommittee again expressed the view that the plans

were very reasonable and presented good opportunities to learn the operational

difficulties of these systems and to be in the best position to utilize the resources

that are being provided to obtain detailed data characterizing urban fine PM.

c) Monitoring - Additional minor concerns were raised regarding the monitoring

activities:

(1) Availability of Data - First, while considerable work has been done in the

Agency to characterize the FRM monitor, the results have not yet been presented

in the peer-reviewed journal literature. The data that will come from the mass

monitoring network will be more useful to health and other studies if the

conditions by which particles are sampled and measured are well characterized and

reported to the broader research community. It will be easier to have an

appropriate scientific discussion of the strengths and weaknesses of the current

method compared to alternatives if the calibration and intercomparison data on the

methods have been published in the peer-reviewed literature. Although some

detailed information on the sampler performance is appropriate for EPA reports,

the Subcommittee strongly urges the Agency to make publication of results a high

priority activity of its research staff.

(2) Utilization of Data - The second concern is the provision for sufficient time and

resources to fully utilize the extensive quantity of data that will be collected as a

result of the Fine PM Monitoring Program. The Agency has often put far more

resources into obtaining high quality data to characterize environmental systems

than it has put into the extraction from the data of the information that would

really provide the depth of understanding needed to solve the complex healthrelated issues associated with PM. Thus, although the initial plans for developing a

significant program of data analysis were encouraging, the Subcommittee will

certainly will be watching carefully to see that appropriate opportunities are being

provided to analyze and interpret the results of the monitoring data.
6

3. Next Steps for the Subcommittee

The Subcommittee plans to hold several meetings over the next few years to respond to its

developing charge and to ensure that appropriate coordination is maintained with the NRC

Committee. The next Subcommittee meeting is planned for May 1999. One of the tasks will be

the development of a plan with respect to how often the Subcommittee should be providing

advice and what kind of reports would be most useful to the Agency and to the Congress.

The Subcommittee would like to complement Agency personnel for their positive

response to advice with respect to the speciation network and supersite plans from external

scientific advisory groups such as the NRC Committee, the Speciation Network Expert Panel, and

the North American Research Strategy for Tropospheric Ozone (NARSTO) Supersite Workshop. 

They have listened to the concerns, proposed changes, and made appropriate revisions to their

plans. These changes will result in the networks providing better data for research purposes while

still meeting the implementation-related objectives for which the networks were originally

designed. We hope that the input of the CASAC Technical Subcommittee on Fine PM

Monitoring will provide a continuing interaction that will permit the most effective use of the

monitoring network and the resulting data to help to resolve some of the uncertainties that remain

regarding airborne particulate matter and adverse health effects. 

Sincerely,

Dr. Philip Hopke, Chair

Technical Subcommittee on Fine Particle Monitoring

Clean Air Scientific Advisory Committee
R - 1

REFERENCES CITED

CASAC. 1996. Report of CASAC Technical Subcommittee for Fine Particle Monitoring. EPASAB-CASAC-LTR-96-009, Clean Air Scientific Advisory Committee, Science Advisory

Board, USEPA, Washington, DC

NRC. 1998. Research Priorities for Airborne Particulate Matter. I - Immediate Priorities and a

Long-Range Research Portfolio. National Research Council. National Academy Press,

Washington, DC. 195p.
A- 1

APPENDIX A

Review Documents provided to the Subcommittee

Attachment 1 - Overview of National PM2.5 Monitoring Networks

Attachment 2 - Chemical Speciation Guidance (July 1998 draft)

Attachment 3 - Supersites Workshop Report: Report of the PM Measurements research

Workshop

Attachment 4 - EPA Supersites concept paper reflecting inputs from workshop Report and

September 24 NAS meeting: Draft Supersites Conceptual Paper

Attachment 5 - EPA Letter to 1996 CASAC Technical Subcommittee for Fine Particle

Monitoring

Attachment 6 - CASAC Summary letter report of 1996 CASAC Technical Subcommittee for Fine

Particle Monitoring

Attachment 7 - Recommendations of the Expert Panel on the EPA Speciation Network

Attachment 8 - Field program Plan for the PM2.5 Chemical Speciation Sampler Evaluation Study

Attachment 9 - Grant Guidance for Fine Particulate Ambient Air Monitoring Program

Attachment 10 - PM2.5 Monitoring Implementation Plan Executive Summary

Attachment 11 - July 1997 Federal Register Notice containing the Monitoring Regulation

Attachment 12 - EPA’s PM Research Overview

Information on many of these documents can be found at:

http://www.epa.gov/ttn/amtic/amticpm.html

or

http://www.epa.gov/ttn/amtic/pmspec.html
i

U.S. Environmental Protection Agency

Science Advisory Board

Clean Air Scientific Advisory Committee

CASAC Technical Subcommittee on

Fine Particle Monitoring

Chair

Dr. Phil Hopke, Clarkson University, Potsdam, NY (Member of CASAC) 

Members of CASAC

Dr. John Elston, State of New Jersey, Dept. Of Environmental Protection & Energy, Trenton, NJ

(Member of CASAC)

Dr. Warren White, Washington University, St. Louis, MO (Member of CASAC)

Members of Other SAB Committees

Dr. JoAnn Lighty, University of Utah, College of Engineering, Salt Lake City, UT (Member and Liaison

from SAB Environmental Engineering Committee)

Dr. Morton Lippmann, Nelson Institute of Environmental Medicine, New York University, Tuxedo, NY

(Member of the SAB Executive Committee)

Consultants to CASAC

Dr. Petros Koutrakis, Harvard University, Boston, MA 

Dr. Debra Laskin, Environmental & Occupational Health Sciences Institute, Rutgers University,

Piscataway, NJ

Dr. Peter H. McMurry, University of Minnesota, Department of Mechanical Engineering, Minneapolis,

MN

Dr. Kimberly A. Prather, Department of Chemistry, University of California-Riverside, Riverside, CA

Dr. Carl M. Shy, Department of Epidemiology, University of North Carolina at Chapel Hill, School of

Public Health, Chapel Hill, NC

Dr. George T. Wolff, General Motors, Public Policy Center, Detroit, MI 48202 

Mr. Mel Zeldin, Monitoring and Analysis Division, South Coast Air Quality Management District

(SCAQMD), Diamond Bar, CA

Science Advisory Board Staff

Mr. A. Robert Flaak, Designated Federal Officer, US EPA, Science Advisory Board, Washington, DC

Ms. Diana Pozun, Management Assistant, US EPA, Science Advisory Board, Washington, DC
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