UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

 WASHINGTON D.C. 20460 

April 20, 2005 

EPA-SAB-CASAC-05-006 

OFFICE OF THE ADMINISTRATOR 

SCIENCE ADVISORY BOARD 

Honorable Stephen L. Johnson 

Acting Administrator 

U.S. Environmental Protection Agency 

1200 Pennsylvania Avenue, NW 

Washington, DC 20460 

Subject: Clean Air Scientific Advisory Committee (CASAC) Advisory on 

Implementation Aspects of the Agency’s Final Draft National Ambient Air 

Monitoring Strategy (NAAMS) (December 2004) 

Dear Acting Administrator Johnson: 

The Clean Air Scientific Advisory Committee’s (CASAC) Ambient Air Monitoring and 

Methods (AAMM) Subcommittee (“Subcommittee”) met on December 15, 2004 to conduct an 

advisory meeting on implementation aspects of the Agency’s Final Draft National Ambient Air 

Monitoring Strategy (NAAMS or “Strategy”). The public meeting was held at the staff offices 

of the EPA Science Advisory Board (SAB) in Washington, DC. Members of the Subcommittee 

are recognized, national-level experts in one or more of the following disciplines or areas: (1) 

atmospheric sciences and air quality simulation modeling; (2) human health effects and exposure 

assessment; (3) air quality measurement science; (4) ecological risk assessment; and (5) State, 

local agency or Tribal experience. The Subcommittee roster is found in Appendix A of this 

report. 

In general, the CASAC finds that the Agency’s ambient air quality monitoring program is 

beginning to implement the changes necessary to bring it in line with the NAAMS strategy 

document. There are and will be a number of scientific issues that will arise as the progress is 

made in reconfiguring the network and as new knowledge with respect to monitoring, modeling, 

and effects becomes available. CASAC AAMM Subcommittee members’ individual review 

comments are provided in Appendix B. 

1. Background 

The CASAC, which comprises seven members appointed by the EPA Administrator, was 

established under section 109(d)(2) of the Clean Air Act (42 U.S.C. 7409) as an independent 

scientific advisory committee, in part to provide advice, information and recommendations on 

the scientific and technical aspects of issues related to air quality criteria and national ambient air 
quality standards (NAAQS) under sections 108 and 109 of the Act. The CASAC, which is 

administratively located under the SAB Staff Office, is a Federal advisory committee chartered 

under the Federal Advisory Committee Act (FACA), as amended, 5 U.S.C., App. The SAB Staff 

Office established the CASAC AAMM Subcommittee in July 2004 as a standing subcommittee 

to provide the EPA Administrator, through the CASAC, with advice and recommendations, as 

necessary, on topical areas related to ambient air monitoring, methods and networks. The 

Subcommittee complies with the provisions of FACA and all appropriate SAB Staff Office 

procedural policies. 

In late 2002, EPA’s Office of Air Quality Planning and Standards (OAQPS), located 

within the Office of Air and Radiation (OAR), issued a draft National Ambient Air Monitoring 

Strategy. OAQPS subsequently requested that the CASAC review the draft NAAMS document 

and provide advice and recommendations to the Agency on the technical bases and design 

aspects of the Strategy. The SAB Staff Office announced the formation of the NAAMS 

Subcommittee of the CASAC on November 5, 2002 (67 FR 67403). The CASAC NAAMS 

Subcommittee held a public meeting in Research Triangle Park, North Carolina, on July 8-9, 

2003 (68 FR 34945, June 11, 2003) to conduct this review of the draft Strategy document. The 

primary recommendations of the CASAC NAAMS Subcommittee, through the chartered 

CASAC, included a request for an implementation plan, and added emphasis on rural- and 

ecosystem-oriented monitoring, support for the National Core Monitoring Network (NCore) 

Level 1 program, and training and quality assurance to enhance data consistency across the 

Nation. The CASAC NAAMS Subcommittee’s complete report from this review is found on the 

SAB Web page at URL: http://www.epa.gov/sab/pdf/casacl04001.pdf. OAQPS updated the 

NAAMS document after the CASAC’s review of the Strategy. The revision incorporated EPA’s 

responses to the CASAC NAAMS Subcommittee’s recommendations. 

Last spring, the SAB Staff Office announced (69 FR 19180, April 12, 2004) the 

formation of the CASAC AAMM Subcommittee. This subcommittee replaced the former 

CASAC NAAMS Subcommittee. Subsequently, OAQPS asked the CASAC AAMM 

Subcommittee to conduct an advisory meeting for the purpose of providing advice and 

recommendations on the implementation plan for its updated final draft NAAMS, which is 

posted on EPA’s Ambient Monitoring Technology Information Center (AMTIC) Web site at the 

following URL: http://www.epa.gov/ttn/amtic/files/ambient/monitorstrat/allstrat.pdf. 

2. CASAC AAMM Subcommittee Advisory on Implementation Aspects of the Agency’s 

Final Draft NAAMS 

The purpose of this meeting was to review the progress toward implementation of the 

Final Draft NAAMS. The OAQPS requested that the Subcommittee provide expert advice and 

recommendations on the following charge questions, which focus on key implementation issues: 

1. The CASAC has expressed its support for the Agency’s proposal to redesign the routine 

PM monitoring network to support PM precursor gas measurements (CO, SO2, NO/NOx, 

NH3, HNO3) at NCore Level II multiple-pollutant sites, and for air quality management 

decisions and to obtain relevant exposure data for research programs. Given limited 

budgetary resources, does this represent both an appropriate and adequate balance, as 

reflected by the relative resource allocations provided in Section 11, “Draft 

2
Implementation Plan,” of the Final Draft NAAMS Document? In addition, are the 

relative adjustments in the training and guidance approaches proposed in the draft 

implementation plan consistent with the overall objectives of the Strategy? 

2. The implementation plan proposes a series of communication actions to advance the 

NCore Level 2 network, in order to more directly support long-term health effects 

research and provide better support to ecosystem assessments through an increased level 

of coordination. Does the CASAC AAMM Subcommittee have additional suggestions 

for addressing this need for integration and communication to the broader community of 

“users,” including scientific researchers (i.e., human health, atmospheric, ecological) and 

State, local and Tribal (SLT) Agency representatives? More specifically, what is the 

most effective manner for EPA both to reach-out to this broad user community and, 

where appropriate, to incorporate their feedback and design input on such issues as 

monitoring site locations and parameters? 

3. One of the remaining technical issues relates to harmonizing rural- and urban-based 

PM2.5 chemical speciation networks such that both categories of networks utilize 

consistent sampling and analysis protocols. For example, EPA is considering converting 

all of the Speciation Trends Network (STN) speciation sites to Interagency Monitoring of 

Protected Visual Environments (IMPROVE) samplers and IMPROVE laboratory and 

sample handling protocols. What are strengths and weaknesses of this approach? 

4. As EPA implements the National Ambient Air Monitoring Strategy to address multiple 

monitoring objectives, it will be looking to spatially optimize the ambient monitoring 

networks. This may mean that some redundant monitors in adjacent, but separate, 

geopolitical areas (e.g., neighboring counties) are “divested” from a given network. 

Although technically sound, these divestments could result in data gaps which might, in 

turn, adversely impact regulatory decision-making. The Agency is willing to adopt 

alternative approaches for assessing regulatory issues such as non-attainment 

designations, so long as such approaches are scientifically justifiable; hence, the rationale 

for initiating discussion of these issues with the CASAC. Is it scientifically acceptable to 

generate isopleths of airborne species concentrations through modeled observations 

and/or integrated predictive/observational fields that would be of appropriate uncertainty 

for use in the regulatory decision-making process? 

Before the discussion of the implementation plan and related issues, the Subcommittee 

would like to commend the OAQPS staff for the responsive manner in which they have revised 

the original draft monitoring strategy in response to the comments provided by the CASAC 

NAAMS Subcommittee (EPA-SAB-CASAC-LTR-04-001) [the URL for this report is found in 

the Background section above]. Several members of the present Subcommittee were also 

members of this earlier group, and there was strong approval by these individuals to the changes 

that have been made in the Final Draft NAAMS Document. 

The Subcommittee discussed these issues sequentially and this report will provide the 

subcommittee recommendations. Individual comments from the subcommittee members on each 

of these issues are provided in Appendix B to this report. 

3
Question 1 

The first issue is that of resource allocation as the redeployment of monitoring resources 

starts to be implemented. The Subcommittee continues to support the need for Level 1 (L1) sites 

as a means for testing of new monitoring technology and moving it to routine use. Substantial 

advances in monitoring technology have been obtained through the EPA Particulate Matter (PM) 

Supersites. That exercise provided the opportunity to test and refine new instrument concepts. It 

is recognized that such an effort cannot be sustained at the level of the Supersites, but some level 

of continuing support is critical to continue the improvements in data that are needed to provide 

the underpinning of future regulatory decisions. Since one of the main purposes of L1 sites 

would be to help transition new methods into routine use, it may be useful to develop the L1 sites 

as cooperative efforts between a research team and state or local regulatory agency personnel. 

There was some discussion as to potential sources of funding that could be diverted to the 

establishment of L1 sites. There were suggestions from several members that Photochemical 

Assessment Monitoring Stations (PAMS) monitoring could potentially be reduced beyond the 

recommendations of the implementation plan. It may be that there is not a need for as many 

standard monitors and that more advanced instrumentation integrated with a few L1 sites or 

limited duration special studies might be more effective in providing the information needed for 

making the needed air quality management decisions. However, in those locations where it is 

felt useful to maintain existing data collection, consideration should be given to extending this 

operation through the entire year. Although it is unlikely that there will be ozone violations in 

the winter, the data on organic constituents can be useful for understanding exposures to and 

sources of toxic hydrocarbons and PM2.5 precursors, for tracking effects of changes in gasoline 

or diesel fuel content, and for evaluating emissions inventories and air quality models. 

An important consideration is the allocation of resources for data analysis as an integral 

part of the network. End uses of the data are too often afterthoughts, and planning for an initial 

set of data analyses is an essential part of the design process. There are too many examples of 

inadequate planning and resources to use the data collected by routine network operations and it 

would be useful to better match the data uses with the effort to acquire the data as an integral part 

of the overall plan. Although all of the possible uses for data cannot be anticipated, many of the 

typical analyses can be anticipated and included in the implementation plans together with the 

requisite budget. CASAC strongly recommends that the Agency give greater consideration to 

identification of the amounts of financial and human resources that will be allocated for data 

analyses and interpretation activities. In this connection we call special attention to the written 

comments on “outreach and extension of findings” and “analysis and interpretation of 

monitoring results” by CASAC members in Appendix 2. 

There were suggestions that there needed to be more effort placed on time-resolved 

measurements. Long-term integrated measurements lose critical information. It is generally 

better to get more detailed time-resolved information for shorter time intervals than to have long 

time interval integrated measurements. With careful design and appropriate statistical methods, 

these episodic measurements can still lead to adequate descriptions of annual averages and 

trends. There is so much additional benefit to the time-resolved measurements that the effort 

needs to be made to move strongly in that direction. As indicated in the report from the earlier 

4
Subcommittee on Fine Particle Monitoring, it is important to retain an appropriate number of 

integrated filter samplers to provide a basis for comparisons with the past monitoring record and 

appropriate quality assurance checks on the monitoring program. 

Although the commercially-available instruments commonly used for measuring NOx 

concentrations are appropriate for ensuring compliance with the health-based national ambient 

air quality standard for nitrogen oxides, they are not sensitive enough to be useful for making 

decisions about NOx vs. VOC sensitivity of ozone non-attainment areas. Such information is also 

important for understanding particulate matter formation. Most commercial instruments have a 

minimum detection limit for NO of about 1 ppb, but decisions about NOx vs. VOC sensitivity 

require instruments that have minimum detection limits of about 0.1 ppb. Similarly there is a 

need for improvements in other gas phase species methods to provide the sensitivity required for 

all of the other objectives other than compliance testing. There is also a need for more 

measurements of key gas-phase species like NH3 and HNO3. At this time it appears there needs 

to be additional development efforts to provide semi-continuous measurements of these species 

and their particle-phase counterparts. 

Finally, there needs to be greater consideration of general HC characterizations in NCore. 

The treatment of carbonaceous compounds is currently a weak part of the monitoring strategy. 

As a first step, continuous total NMOC measurements should be included in the NCore L2 sites 

or at least a subset thereof. 

With the promulgation of the Clean Air Mercury Rule on March 15, 2005 that will 

require controls on mercury emissions from coal-fired power plants, it is important that 

monitoring be put in place to measure the atmospheric concentrations of mercury species. Such 

an effort should be put in place as quickly as possible so as to gather baseline data before 

controls can actually be put in place and maintained for a sufficiently long period as to ascertain 

the changes in atmospheric concentrations that occur as a result of these controls. Given that 

there is likely to be regional caps, as part of a cap and trade program, appropriate regional 

strategies will be needed to provide the necessary accountability data. 

Question 2 

There is consensus within the committee that the single most effective way for EPA to 

reach out to potential users of its data is to make these data easily accessible via the internet. The 

committee was encouraged by the staff presentation on current plans for Web access, and 

expressed a desire to move rapidly toward getting this portal into operation with the flexibility to 

adjust it as experience with its use is obtained. There is concern that there may be bottlenecks 

between network operation and data availability. We support pushing the access to raw data 

behind EPA’s “AIRNow” Web site as quickly as possible and would like to encourage their 

Steering Committee to move things ahead. 

Another issue that needs to be addressed is computer-to-computer access. For users who 

continuously update graphical displays or model calculations, access for an automatic download 

of data is an important aspect of the accessibility of the data. Providing protocols for such access 

should be part of the plans for the data access Web site. 

5
It would be helpful to combine ancillary data from other agencies such as the visibility 

data from airports into the data base. It may be useful for EPA to discuss the development of 

combined data sets with the variety of other Federal agencies that have air-quality data sets such 

as NASA, NOAA, and DOE. 

In terms of communications, it may be useful to consider organizing regional workshops 

to get broader input into network modifications and data use. In particular, this may be the 

appropriate way to bring the ecological community into the discussions. The move to site more 

monitoring in rural areas needs the active participation of the ecological community to balance 

the needs of the air quality modelers with those interested in understanding the ecological effects 

of air pollution. Since ecosystems vary widely from region to region across the country, regional 

workshops or similar forums can provide a means for meaningful participation by those 

interested in ecological systems. 

It is not clear that additional efforts are needed to get the health community involved 

other than making the data readily-accessible. It is likely that a number of health researchers 

would make use of data if they are easily accessible. However, changes to the network affect the 

ability of epidemiologists to use the data and there needs to be effective communication with this 

community to permit EPA to understand the potential impacts of any changes that are planned 

for the network. The network is being redeployed to serve multiple objectives and regulatory 

needs will take priority, but good communications can permit maximal exchange of points of 

view and an opportunity to make better decisions on the redeployment of monitors. 

Question 3 

There is strong general support for making substantial changes to the 54 STN Trends 

sites to ensure compatibility with IMPROVE data. Currently, it is not possible to fully combine 

STN and IMPROVE data in spatial studies or in model evaluations since there are significant 

differences in sampling and analysis. However, it needs to be fully understood what is meant by 

IMPROVE-protocol sites. At present, the IMPROVE program controls all aspects of the system 

from sampling to analysis. STN utilizes state and local agencies to operate the samplers. 

The IMPROVE sampler uses a critical orifice rather than active flow control, and thus, 

provides a less stable particle-size cutpoint. IMPROVE uses 25 mm filters and higher flow rates 

that have the advantage of having higher areal density of material on the filters as compared with 

the STN samplers. However, there has been concern regarding the possibility of clogging of the 

Teflo filters that could lead to invalid samples during extreme events and/or to changes in the 

cut-point for the cyclone inlets. IMPROVE-protocol sampling has been conducted in 

Washington, DC; Seattle, WA; and Phoenix, AZ for a number of years without clogging being a 

substantial problem. The IMPROVE experience has been that clogging has only been observed 

in major fire episodes so it may not be a problem or could be accommodated by changing the 

sampling protocol to a half-hour within each hourly time interval or by terminating the sample at 

less than 24 hours if flow rates drop significantly. These data would be flagged appropriately to 

indicate that they do not represent the full time interval. 

6
There are existing problems of harmonization of data from IMPROVE and STN that need 

to be addressed. It has recently been recognized that there are significant differences in the XRF 

results from the two networks and quite different approaches to the reporting of errors for the 

XRF results. There are now on-going discussions between RTI, ChesterNet Lab and the 

University of California at Davis regarding the XRF analyses and reporting of the XRF errors, 

and it is anticipated that these differences may be resolved. There may need to be some 

additional samples run by all of the laboratories in round robin studies to resolve discrepancies in 

the values and reported errors, and OAQPS should support these efforts. 

There are substantial differences in the organic and elemental carbon fraction (OC/EC) 

methods. These differences have been reported in the literature. However, there is no “right” 

answer since the measured species are defined by the analytical method. IMPROVE uses a 

dynamic blank to correct the OC data while STN uses only field and laboratory blanks. Blank 

sampling and reporting is thus an area requiring harmonization. Another key issue is the type of 

filter. Because of potential differences in the type of quartz filters used by the STN and 

IMPROVE programs, it is recommended that the STN use the same filter type as used by 

IMPROVE (i.e., Pall Tissuequartz) to ensure consistency. There are a number of other issues 

such as differences in the storage, the analysis of cations, shipping conditions, etc. that need to be 

harmonized. It should be noted that IMPROVE will soon be changing their method because of 

the need to replace the existing analytical instruments. A commercial instrument is now 

available to implement the IMPROVE time-temperature protocol. Studies to date suggest that 

the OC and EC values by both the old and new instruments are comparable, but the values of the 

thermal fractions can have significant variations. There will then be changes in the data being 

reported in the IMPROVE network. Therefore, it is an appropriate time to change the STN 

network to what will shortly be the new IMPROVE protocol so that there will be comparability 

between the measurements. 

Thus, the key question is whether or not to change the Trends sites to the IMPROVE 

protocol at this time. If these 54 STN sites are fully converted to IMPROVE, it will guarantee 

the comparability of the data and thus, permit the comprehensive use of the compositional data 

obtained in the future. For other sites in the network, it would be useful to provide this 

alternative to the SLT organizations that are control these sites. At this time, it is unclear if there 

is sufficient capacity at the University of California at Davis to handle these additional sites. If 

the filter preparation and analyses are done by the existing STN contractor, there will still be a 

problem of data harmonization that needs to be addressed to ensure comparability of results from 

the different laboratories. The Subcommittee recommends that to achieve fully comparable data, 

it will require that all of the samples be collected in an identical manner with identical samplers. 

The samples would then be analyzed by a single laboratory for any given chemical constituent 

with a single approach to error estimation, data validation, etc. 

The decision to change the monitoring approach for the STN and/or the IMPROVE 

network must also take into account emissions sampling protocols and methods. If the two 

databases are incompatible, this will inhibit accurately identifying source impacts. Similar 

studies that compare ambient measurements (i.e., between the IMPROVE and STN methods) 

need to be done for emissions measurements. If one technique (e.g., the NIOSH vis B vis 

IMPROVE for EC/OC) proves better for conducting emissions measurements (i.e., provides a 

7
more stable measurement), this should affect the choice for use in ambient monitoring (and vice 

versa). Whichever techniques are ultimately used, all parties should recognize and account for 

these tangential impacts and issues. Thus, there also needs to be the development of source 

sampling methods that utilize the same sampling and analytical methods as the ambient network 

so that the resulting source characterizations can be used in the interpretation of the ambient 

aerosol composition data. 

Question 4 

The generation of surfaces of air quality parameters needs to be generated by a 

combination of measurements and model simulations. Both measurements and model results 

have uncertainties associated with them. Measurements are made at specific locations and 

represent a limited geographical area. Alternatively, models average results over the minimum 

size of the grid cell and cannot fully reproduce the local environment. 

Thus, the use of integrated predictive/observational fields is the preferred approach. 

While there is much work to be done here, this approach will help tackle multiple issues. First, it 

is probably the best way to extend an observation (or sets of observations) both spatially and 

temporally, if necessary. Second, it can be used in the process of source apportionment (or viceversa: source apportionment can be used in extending the use of observations). Third, it will 

help identify uncertainties in the representativeness of the observations at a monitoring location. 

Fourth and finally, it will produce the type of information that can be used by groups identified 

in Question 2. 

 Therefore, conceptually the combination approach is the appropriate way to proceed. 

However, we still do not have the best approach laid out, and the enabling technologies 

developed (e.g., software/hardware environments to provide this information). These issues can 

probably be tackled within three or four years. Such a process should utilize the observations 

available, both in situ and remote (for example, satellite) as well as PM modeling (with data 

assimilation). There should be a feedback loop where the information provided by the integrated 

system utilizes additional approaches to assess the quality of the fields developed (e.g., data 

withholding, etc.). While this may seem ambitious, EPA should set as a goal, to have a field of 

source apportioned daily/monthly/yearly PM for the U.S. by 2010 (e.g., target PM2.5 and coarse 

PM for 2008, with the apportioned fields developed by 2010). The work should also include 

fields of the uncertainties in the integrated daily PM levels and, at least, in the annual source 

apportionments. These results should be updated on an ongoing, annual basis. If the resources 

were currently available, it is likely that this integrated approach could be achieved by 2008 

(using 2006 data). 

Thus, we find that the Agency’s ambient air quality monitoring program is beginning to 

implement the changes necessary to bring it in line with the NAAMS strategy document. There 

are and will continue to be a number of scientific issues that arise both as progress is made in 

reconfiguring the network and as new knowledge with respect to monitoring, modeling, and 

effects becomes available. Thus, there is the need for a continuing process for the ongoing 

review and assessment of the monitoring program. The CASAC has found it to be very valuable 

to review and offer its advice and recommendations to the Agency in the development of the 

current monitoring strategy, and further advises that periodic reevaluation be built into the 

8
monitoring network plans to ensure that the network continues to meet the multitude of needs 

that are expected to change over time. Therefore, we recommend that the CASAC Ambient Air 

Monitoring and Methods Subcommittee continue to serve in this role. As always, the CASAC 

wishes the Agency well in this very important endeavor. 

 Sincerely, 

/Signed/ 

Dr. Rogene Henderson, Chair 

 Clean Air Scientific Advisory Committee 

Appendix A – Roster of the CASAC AAMM Subcommittee 

Appendix B – Review Comments from Individual CASAC AAMM Subcommittee Members 

cc: Steve Page (MD-10) Jake Summers (MD-12) 

 Rich Scheffe (MD-14) Anthony Maciorowski (1400F) 

 Phil Lorang (MD-14) Fred Butterfield (1400F) 

 Tim Hanley (MD-14) 

9 
Appendix A – Roster of the CASAC AAMM Subcommittee 

U.S. Environmental Protection Agency 

Science Advisory Board (SAB) Staff Office 

Clean Air Scientific Advisory Committee 

CASAC Ambient Air Monitoring and Methods (AAMM) Subcommittee* 

CHAIR 

Dr. Philip Hopke, Bayard D. Clarkson Distinguished Professor, Department of Chemical 

Engineering, Clarkson University, Potsdam, NY 

Also Member: SAB Board 

CASAC MEMBERS 

Dr. Ellis Cowling, University Distinguished Professor At-Large, North Carolina State 

University, Colleges of Natural Resources and Agriculture and Life Sciences, North Carolina 

State University, Raleigh, NC 

Mr. Richard L. Poirot, Environmental Analyst, Air Pollution Control Division, Department of 

Environmental Conservation, Vermont Agency of Natural Resources, Waterbury, VT 

SUBCOMMITTEE MEMBERS 

Mr. George Allen, Senior Scientist, Northeast States for Coordinated Air Use Management 

(NESCAUM), Boston, MA 

Dr. Judith Chow, Research Professor, Desert Research Institute, Air Resources Laboratory, 

University of Nevada, Reno, NV 

Mr. Bart Croes, Chief, Research Division, California Air Resources Board, Sacramento, CA 

Dr. Kenneth Demerjian, Professor and Director, Atmospheric Sciences Research Center, State 

University of New York, Albany, NY 

Dr. Delbert Eatough, Professor of Chemistry, Chemistry and Biochemistry Department, 

Brigham Young University, Provo, UT 

Mr. Eric Edgerton, President, Atmospheric Research & Analysis, Inc., Cary, NC 

Mr. Henry (Dirk) Felton, Research Scientist, Division of Air Resources, Bureau of Air Quality 

Surveillance, New York State Department of Environmental Conservation, Albany, NY 

A-1 
Dr. Rudolf Husar, Professor, Mechanical Engineering, Engineering and Applied Science, 

Washington University, St. Louis, MO 

Dr. Kazuhiko Ito, Assistant Professor, Environmental Medicine, School of Medicine, New 

York University, Tuxedo, NY 

Dr. Donna Kenski, Data Analyst, Lake Michigan Air Directors Consortium, Des Plaines, IL 

Dr. Thomas Lumley, Associate Professor, Biostatistics, School of Public Health and 

Community Medicine, University of Washington, Seattle, WA 

Dr. Peter McMurry, Professor and Head, Department of Mechanical Engineering, Institute of 

Technology, University of Minnesota, Minneapolis, MN 

Dr. Kimberly Prather, Professor, Department of Chemistry and Biochemistry, University of 

California, San Diego, La Jolla, CA 

Dr. Armistead (Ted) Russell, Georgia Power Distinguished Professor of Environmental 

Engineering, Environmental Engineering Group, School of Civil and Environmental 

Engineering, Georgia Institute of Technology, Atlanta, GA 

Dr. Jay Turner, Associate Professor, Chemical Engineering Department, School of 

Engineering, Washington University, St. Louis, MO 

Dr. Warren H. White, Visiting Professor, Crocker Nuclear Laboratory, University of California 

- Davis, Davis, CA 

Dr. Yousheng Zeng, Air Quality Services Director, Providence Engineering & Environmental 

Group LLC, Baton Rouge, LA 

SCIENCE ADVISORY BOARD STAFF 

Mr. Fred Butterfield, CASAC Designated Federal Officer, 1200 Pennsylvania Avenue, N.W., 

Washington, DC, 20460, Phone: 202-343-9994, Fax: 202-233-0643 (butterfield.fred@epa.gov) 

(Physical/Courier/FedEx Address: Fred A. Butterfield, III, EPA Science Advisory Board Staff 

Office (Mail Code 1400F), Woodies Building, 1025 F Street, N.W., Room 3604, Washington, 

DC 20004, Telephone: 202-343-9994) 

* Members of this CASAC Subcommittee consist of: 

a. CASAC Members: Experts appointed to the statutory Clean Air Scientific Advisory Committee 

by the EPA Administrator; and 

b. CASAC Subcommittee Members: Experts appointed by the SAB Staff Director to serve on one 

of the CASAC’s standing subcommittees. 

A-2 
Appendix B – Review Comments from 

Individual CASAC AAMM Subcommittee Members 

This appendix contains the preliminary and/or final written review comments of 

the individual members of the Clean Air Scientific Advisory Committee (CASAC) 

Ambient Air Monitoring and Methods (AAMM) Subcommittee who submitted such 

comments electronically. These comments are included here to provide both a full 

perspective and a range of individual views expressed by the Subcommittee members 

before, during and after the Subcommittee’s December 15, 2004 advisory meeting on 

implementation aspects of the Agency’s Final Draft National Ambient Air Monitoring 

Strategy (NAAMS). These comments do not represent the consensus views of the 

CASAC AAMM Subcommittee, the CASAC, the EPA Science Advisory Board, or the 

Environmental Protection Agency (EPA) itself. The list of Subcommittee members 

providing individual comments is provided on the next page, and their review comments 

follow. 

B-1 
Panelist Page # 

Dr. Ellis Cowling ........................................................................................ B-3

Mr. Richard L. Poirot ................................................................................... B-11

Mr. George Allen ....................................................................................... B-17 

Dr. Judith Chow ......................................................................................... B-20 

Mr. Bart Croes ........................................................................................... B-29 

Dr. Kenneth L. Demerjian .............................................................................. B-33 

Dr. Delbert Eatough .....................................................................................B-36 

Mr. Eric Edgerton ........................................................................................B-41 

Mr. Henry (Dirk) Felton ................................................................................ B-44 

Dr. Rudolf Husar ........................................................................................ B-48 

Dr. Kazuhiko Ito .........................................................................................B-53 

Dr. Donna Kenski .......................................................................................B-56 

Dr. Thomas Lumley .....................................................................................B-58 

Dr. Peter McMurry ...................................................................................... B-61 

Dr. Armistead (Ted) Russell............................................................................B-65 

Dr. Jay Turner ............................................................................................B-70 

Dr. Warren H. White .................................................................................... B-73 

Dr. Yousheng Zeng ......................................................................................B-75

B-2 
Dr. Ellis Cowling 

Comments by Ellis Cowling on 

Implementation Aspects of EPA’s National Air Monitoring Strategy (NAAMS) 

After careful reading of all 12 sections of the Final Draft NAAMS and many of the 164 public 

comments and EPA responses in the Addendum to the Final Draft, I offer the following 

comments especially with regard to the first question in the Charge to the CASAC Ambient Air 

Monitoring Subcommittee. 

General Comment 1) 

With regard to the Agency’s proposal to redesign the routine precursor gas measurements (CO, 

SO2, NO/NOy NH3, HNO3) at NCore Level II multiple pollutant sites and for air quality 

management decisions and to obtain relevant exposure data for research programs, permit me to 

mention that scientists in the Southern Oxidants Study drew the following general conclusion 

from our major field measurement campaigns in Atlanta and Nashville in 1990, 1992, 1994, and 

1999: 

“In comparison with research-grade instruments, the commercially-available instruments 

commonly used for measuring NOx concentrations in air: are not sensitive enough to 

measure NO reliably, and are not specific enough to measure NO2 reliably.” 

Although the commercially-available instruments commonly used for measuring NOx 

concentrations are appropriate for ensuring compliance with the health-based national ambient 

air quality standard for nitrogen oxides, they are not sensitive enough to be useful for making 

decisions about NOx vs. VOC sensitivity of ozone non-attainment areas. Most commercial 

instruments have a minimum detection limit for NO of about 1 ppb, but decisions about NOx vs. 

VOC sensitivity require instruments that have minimum detection limits of about 0.1 ppb. 

Perhaps I missed it, but I was unable to find in the Final Draft Strategy document an adequate 

discussion of the minimum detection limits for nitrogen oxides and the other precursor gases 

listed above. 

General Comment 2) 

The preamble to Charge Question 1 asks: 

“Given limited budgetary resources ... is the information on resource allocations provided in 

Section 11 with regard to support for PM precursor gas measurements at NCore Level II multiple 

pollutant sites appropriate and well balanced and consistent with the overall objectives of the 

Strategy.” 

My response to this question is: “Yes, in part, with respect to the proposed gas measurements at 

NCore Level II multiple pollutant sites.” 

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The specific wording of Charge Question 1 goes on to ask: “Are the relative adjustments in the 

training and guidance approaches in the plan consistent with the overall objectives of the 

Strategy?” 

My response to this specific question is “Yes, by in large.” But if the question is rephrased -- as 

I believe it should be -- to read: “Are the relative adjustments in the training, guidance, analysis, 

interpretation, and communication approaches consistent with the overall objectives of the 

Strategy?” my response would be a resounding “No!” 

Sections 1, 2, 9, 11, and 12 of the Strategy all give strong emphasis to analysis, interpretation, 

and communication of results from the various monitoring networks described in the NAAM 

Strategy. 

This is especially true of the statements in Section 1.2 on ‘Goals and Objectives,’ Section 

1.3 on ‘Scope of Participants and Key Operating Principles’ (most notably) its subsection on 

‘Data Analysis and Interpretation,’ and Section 1.4 on ‘Recommendations” (especially the 

statement “A strong public communications program is advocated, both at national and local 

levels.” 

This is also true of the statements in Section 2.2 on ‘Network Assessment,’ and Section 

2.6 on ‘Communication and Outreach.’ 

It is especially true of many statements in the early parts of Section 9 on 

‘Communications and Outreach,’ (most notably) in Section 9.1.1 on ‘Benefits to State and Local 

Agencies, Public Interest Groups and the General Public,’ Section 9.1.2 on ‘Benefits to the 

research and Academic Community,’ and Section 9.1.3 ‘Benefits to Tribal Communities.’ 

But the description in Section 9.2 about ‘How This Information Will be Communicated’ 

seems to be both ‘inconsistent and not appropriately balanced’ with the statements in Sections 

9.1.1, 9.1.2, and 9.1.3. The ‘Fact Sheet,’ ‘Quarterly Newsletter,’ ‘Specialized Briefing 

Presentations’ using ‘packaged slide presentations,’ and the ‘Monitoring Strategy Brochure’ all 

appear to be focused on descriptions of the ‘monitoring program’ rather than to ‘policy-relevant 

scientific findings’ from the monitoring measurements.’ 

Various parts of Section 11, especially Section 11.3 on ‘Resource and Funding Strategy,’ 

and Section 11.3.1 on ‘Implementation Using Current Funding Basis,’ Tables 11-1 and 11-2 and 

especially Table 11-3 on ‘Proposed summary of redistributed Federal resources,’ and even more 

notably Table 11-6 on ‘Implementation Schedule’ give little or no information on ‘Data 

Analysis,’ and even less information on ‘interpretation,’ ‘communication,’ and ‘outreach.’ 

In Section 12 on ‘Issues’ the distinction between ‘Classical’ and ‘Value’ perspectives is 

discussed. Please note especially the last part of the section on ‘Value:’ 

“The real success of the Strategy ultimately will require ... cultural modification upgrades 

[within both EPA and state, local and tribal communities] that allow for a [more] meaningful 

dialogue across data generators and data user communities.” In this respect the statements in 

Section 12.4 on ‘Addressing Data Availability and Data Analysis Needs,’ and in Section 12.4.2 

on ‘Data Archiving, Distribution and Analysis Efforts’ are relevant. 

So far as I can find in the Strategy document, there is only one monitoring program in 

which a specific discussion about needs for data analysis and interpretation is discussed directly 

with specific dollars allocated for data analysis and interpretation. This is the PAMS program. 

Please note the first paragraph on page 11-5. It reads in part as follows (see also Table 11-3 on 

page 11-9): 

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c. PAMS. PAMS requirements have been scaled down to allow for more specific special 

studies of interest by local area/regions. The current $14 M Federal 105 STAG 

contribution to PAMS should be reduced to $12M, an amount sufficient to cover the 

revised, minimum PAMS monitoring requirements. There has been a wealth of data 

collected from the PAMS program, but very limited and often sporadic analysis and 

interpretation of the data. To address this gap and yield value from the PAMS data bases, 

$0.5M will be set aside for analysis of the PAMS data. 

[This amounts to an allocation of only about 4% of the current annual cost of the PAMS 

program and does not consider cumulative funding for PAMS during years in which 

analysis and interpretation was ‘very limited and often sporadic.’] 

My recommendation is that our CASAC AAMM Sub-Committee offers the following 

recommendations regarding Implementation Aspects of the NAAM Strategy: 

1) Financial and human-resource allocations for analysis, interpretation, and communication 

of monitoring results should be increased substantially for each of the several monitoring 

programs described in the National Ambient Air Monitoring Strategy including the 

programs for SLAMS, NAMS, PAMS, PM2.5, Toxics, CASNET, IMPROVE, and the 

NCore network. 

2) A summary table should be developed for inclusion in a revised Section 11 that shows 

the approximate relative allocations within each monitoring program -- for the 

monitoring measurements themselves, and separately for analysis, interpretation, and 

communication of scientific findings from each of the monitoring networks described in 

the NAAM Strategy. 

3) CASAC should initiate an endeavor together with OAQPS, selected universities, and 

various state, local, regional and tribal organizations of air quality managers. The 

objective would be to: a) Identify individuals and organizations that have been unusually 

successful in analysis, interpretation, and communication of scientific findings from 

monitoring networks; and b) Use these lists to foster and encourage more frequent 

analysis, interpretation, and communication of results from the several monitoring 

networks described in the Final Draft National Ambient Air Monitoring Strategy. In this 

connection, please see the attached documents on the Environmental Statistics Program at 

NC State University 

Further Background Information for General Comment 2: 

On July 22, 2004, CASAC held a "Consultation on Methods for Measuring CoarseFraction Particulate Matter (PMc) in Ambient Air, Based upon Performance Evaluation Studies 

Conducted by EPA." At that time I made two points that may be worth repeating in connection 

with the current CASAC discussions on “Implementation Aspects of the Final Draft of the 

National Ambient Air Quality Monitoring Strategy.” 

Point 1) EPA and many other federal research and monitoring organizations need to guard 

against the tendency to allocate so much of the funds used in monitoring programs and field 

measurement campaigns to "making careful measurements" so that inadequate funds are 

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available for "scientific analysis and interpretation" to determine and communicate to users what 

the measurements really mean. 

These cautionary remarks about problems in field monitoring programs were suggested 

originally by the late Glenn Cass, formerly of Cal Tech and later of Georgia Tech, on the basis of 

his career-long experience in various environmental monitoring programs -- programs in which 

too much funding was allocated to "measurements" and too little to "analysis and interpretation" 

of the data and “communication of results” from the field measurements. In this connection, 

please note the attached excerpts from a paper published in Water, Air and Soil Pollution in 

1995. 

Please also note especially the suggestion in the second item 9 about a "50:50 

distribution" of funding allocations between "measurements" and "analysis and interpretation" of 

monitoring data rather than the (90:10 or 80:20 distribution) that is typical of many monitoring 

programs in EPA and other agencies. But please also note that an even better suggestion was 

made by Mary Barber, former executive leader with the Ecological Society of America who 

spoke in opposition to the "50:50 distribution" idea at a recent Whitehouse Conference on 

monitoring. Mary Barber insisted, and I agree with her, that it would be even more appropriate 

to distribute the funding into three rather than two categories of investments -- with equal shares 

going to "measurements," "analysis and interpretation," and "outreach and extension of findings" 

to interested clientele and "customers" for the results of routine field monitoring programs. 

This problem is so commonplace -- not only in EPA but in many other agencies in this 

country and around the world -- that I commend these "lessons that are available to be learned" 

(and perhaps even the "15 reasons why this happens" and the "13 things to do about it") for 

inclusion among the comments from individual participants in the CASAC meeting on 

“Implementation Aspects of the Final Draft National Ambient Air Monitoring Strategy.” 

Point 2) EPA should also guard against the tendency to give undue emphasis to "Data Quality 

Objectives" in the selection and evaluation of instruments and subsequent implementation of 

field monitoring programs to the exclusion of concern about "Science Quality Objectives" and 

"Policy Relevancy Objectives." 

Experience within the Southern Oxidants Study and other large-scale field measurement 

and monitoring campaigns have demonstrated repeatedly that undue emphasis on "Data Quality 

Objectives" often leads to: 

1) Serious lack of attention to the scientific hypotheses and assumptions that are inherent in 

any choice of scientific instruments, the appropriateness of the ground-based sites at 

which the instruments are located, the skills of the instrument operators, the data 

processing and data-display programs used, and especially the scientific quality of the 

conclusions and statements of findings that are drawn from analysis and interpretation of 

the measurements that are made; and 

2) Equally serious lack of attention to the policy relevancy of the measurements being made 

-- relevancy to the general or specific enhancements of environmental protection that are 

the real reason behind the public health or public welfare concerns that led to the decision 

to establish a monitoring program in the first place. 

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In this latter connection, permit me also to call attention to the attached "Guidelines for 

the Formulation of Scientific Findings to be Used for Policy Purposes." These guidelines 

were developed originally by the NAPAP Oversight Review Board led by Milton Russell, 

former Assistant Administrator for EPA. Please find attached below, an electronic version of 

these Guidelines which we have adopted and very slightly adapted for use in formulating 

policy relevant scientific findings in the Southern Oxidants Study. 

The original version of these Guidelines was published as Appendix III of the April 1999 

Report titled "The Experience and Legacy of NAPAP." This was a Report to the Joint Chairs 

Council of the Interagency Task Force on Acidic Deposition of the Oversight Review Board 

(ORB) of the National Acid Precipitation Assessment Program. As indicated in Appendix 

III: 

“The following guidelines in the form of checklist questions were developed by the 

ORB to assist scientists in formulating presentations of research results to be used in 

policy decision processes. These guidelines may have broader utility in other programs at 

the interface of science and public policy and are presented here with that potential use in 

mind." 

Excerpts from: 

Cowling, E., and J. Nilsson. Acidification Research: Lessons from History and Visions of 

Environmental Futures. Water, Air and Soil Pollution 85:279-292. 1995. 

LESSONS LEARNED ABOUT THE SOCIAL DYNAMICS OF MONITORING PROGRAMS 

AND FIELD RESEARCH CAMPAIGNS 

We also observed that there is a social tendency among research scientists, to spend more time and 

energy developing new monitoring networks than in analysis and interpretation of already existing data, 

especially long time-series measurements. Glen Cass of the California Institute of Technology was one of 

the first to call this tendency to our attention. But we also have discussed this matter with other scientists 

and research leaders in Sweden, Norway, Germany, The Netherlands, Canada, and the United States. As 

a result we have come to believe that there are three general reasons and at least 15 specific reasons why 

this happens and four general things and at least 13 specific things that can be done about it. 

Three General and Specific Reasons Why this happens 

Personal/psychological reasons: 

1) Some scientists think it is not appropriate to analyze data collected by other people. 

2) Some scientists underestimate the time and creative energy it takes to do thorough analysis and 

interpretations of field data. 

3) Some scientists prefer to concentrate on field measurements rather than the sometimes more demanding 

intellectual work of data analysis and interpretation. 

4) Some instrumentalists and data analysts exaggerate small deficiencies in measurement methods so that 

they too readily agree to "get out and do it right" rather than "milk the data for all it is worth" before going 

to the field once again. 

5) The tendency to believe that "there is nothing more tragic than a beautiful hypothesis slain by an ugly 

fact in your own data”. 

6) The tendency to "move on to other things" rather than recognize that “it is a sign of maturity if you 

finish things and a sign of immaturity if you just start new ones”. 

7) Some scientists think analysis and interpretation of long term trends is boring. 

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Social/psychological reasons: 

8) The contagious enthusiasm that field campaigns seem to engender in groups of scientists, and which 

occurs less frequently in the usually more private intellectual work of data analysis and interpretation. 

9) The tendency of some scientists to believe that those who collect the data “own” the data and thus can 

choose (regardless of what organization paid the bills for the program!) when, where, and under what 

circumstances of authorship, priority, etc., the data should be validated, archived, analyzed, interpreted, 

and made available to others. 

10) The tendency of research leaders to avoid conflicts about the policy implications of research findings. 

For example, atmospheric monitoring data usually are not threatening, but data analyses sometimes lead 

to situations that have policy consequences that make for uncomfortable disputes. Since noncontroversial portions of research programs proceed to completion more readily than parts of research 

programs facing opposition, it is not surprising that the atmosphere is over-measured and underinterpreted. 

Budgetary/logistical reasons: 

11) The tendency for unreasonable budget optimism. Exaggerated promises often are made to make a 

project appealing to sponsors -- promises that often cannot be fulfilled with the limited funds that usually 

are available. Since atmospheric or other field measurements occur at the beginning of a research 

program, they often are completed at the expense of resources needed later for thorough analysis and 

interpretation of data. 

12) The tendency to buy what is cheap (or what is easy to do) rather than what is really needed (or may be 

difficult to do). Atmospheric measurements are individually rather cheap. (For example, the elemental 

composition of a single sample of fine particulate matter can be determined for about $120.) But the same 

measurement made within the stack of a particular pollution source may cost many thousands of dollars 

because of logistical difficulties and challenging environmental conditions (e.g., high temperatures). 

13) Field measurement campaigns often are planned too soon after each other. 

14) Granting agencies often assume that if they fund scientists to make field measurements that these 

same scientists will find the time and energy for analysis and interpretation whether they are funded to do 

so or not. 

15) The too dominating role of tradition (what did we do last year?) as the "best guide" to wisdom in 

budget and personnel decisions. 

Four General and Thirteen Specific Things That Can Be Done About It 

Social/political things: 

1) Recognize that monitoring programs cannot be sustained unless there are “customers” who care about 

the data, use the data often, and are willing to speak-out publicly about the constructive values they derive 

from analysis and interpretation of the data. 

Personal/psychological things: 

2) Recognize that people want to enjoy the work they do. Making atmospheric measurements in the field 

is both rewarding and fun. By contrast, collecting and tabulating real-world data regarding amounts of 

emissions can be tedious or even boring. Not surprisingly, few people want to do the necessary but 

boring part, and those who are pushed against their will usually do a sloppy job. Solution: Find ways to 

make data analysis more fun and rewarding! For example, give high praise and other rewards to those 

who willing to do what is necessary whether it is boring or not! 

Scientific/intellectual things: 

3) Formulate specific science and policy questions that are to be addressed and design measurement 

systems to answer those specific questions. 

4) Use available guidelines for formulation of statements of scientific findings to be used for policy 

purposes -- See Appendix III in the Oversight Board Report (NAPAP 1991). 

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5) Place heavy emphasis on publication of results not only in peer-reviewed scientific journals, but also in 

readily accessible professional, environmental, commercial, and public-interest publications and 

electronically accessible information outlets. 

Budgetary/logistical things: 

6) Recognize how many significant scientific discoveries about the phenomena and effects of air pollution 

have been made by analyzing “old” data. 

7) Find and fund those scientists who really enjoy data analysis and interpretation. 

8) Buy the research that is really needed, not what is cheap or convenient. 

9) Recognize that data archiving, analysis, and interpretation are tedious, time consuming, intellectually 

demanding, and expensive. An appropriate ratio for investment in measurements and investments in 

analysis and interpretation generally is closer to 50:50 than the customary ratio of only 10:1 or even 20:1. 

Also, it is valuable to use 2- to 5-year “roll-forward” mechanisms to ensure continuity of funding. 

10) Recognize large measurement campaigns rarely can be sustained in successive years. 

11) Plan research project and programs from the end backward to the start. First, specify the best data 

analysis procedures necessary to answer important science and policy questions within the available funds 

and time. Then, make or complete only those measurements that have a pre-specified place in the dataanalysis plan. 

12) Try to balance uncertainties in the time, cost, and performance of research projects so as to keep all 

three factors approximately on-target. 

13) Initiate and maintain measurement programs to determine the effectiveness of environmental 

management decisions. 

GUIDELINES FOR THE FORMULATION OF SCIENTIFIC FINDINGS 

TO BE USED FOR POLICY PURPOSES 

The following guidelines in the form of checklist questions were developed by the NAPAP Oversight 

Review Board to assist scientists in formulating presentations of research results to be used in policy 

decision processes. 

1) IS THE STATEMENT SOUND? Have the central issues been clearly identified? Does each 

statement contain the distilled essence of present scientific and technical understanding of the 

phenomenon or process to which it applies? Is the statement consistent with all relevant evidenceevidence developed either through NAPAP [or SOS] research or through analysis of research 

conducted outside of NAPAP [or SOS]? Is the statement contradicted by any important evidence 

developed through research inside or outside of NAPAP [or SOS]? Have apparent contradictions or 

interpretations of available evidence been considered in formulating the statement of principal 

findings? 

2) IS THE STATEMENT DIRECTIONAL AND, WHERE APPROPRIATE, QUANTITATIVE? 

Does the statement correctly quantify both the direction and magnitude of trends and relationships in 

the phenomenon or process to which the statement is relevant? When possible, is a range of 

uncertainty given for each quantitative result? Have various sources of uncertainty been identified and 

quantified, for example, does the statement include or acknowledge errors in actual measurements, 

standard errors of estimate, possible biases in the availability of data, extrapolation of results beyond 

the mathematical, geographical, or temporal relevancy of available information, etc. In short, are there 

numbers in the statement? Are the numbers correct? Are the numbers relevant to the general meaning 

of the statement? 

3) IS THE DEGREE OF CERTAINTY OR UNCERTAINTY OF THE STATEMENT 

INDICATED CLEARLY? Have appropriate statistical tests been applied to the data used in drawing 

the conclusion set forth in the statement? If the statement is based on a mathematical or novel 

conceptual model, has the model or concept been validated? Does the statement describe the model or 

concept on which it is based and the degree of validity of that model or concept? 

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4) IS THE STATEMENT CORRECT WITHOUT QUALIFICATION? Are there limitations of 

time, space, or other special circumstances in which the statement is true? If the statement is true only 

in some circumstances, are these limitations described adequately and briefly? 

5) IS THE STATEMENT CLEAR AND UNAMBIGUOUS? Are the words and phrases used in the 

statement understandable by the decision makers of our society? Is the statement free of specialized 

jargon? Will too many people misunderstand its meaning? 

6) IS THE STATEMENT AS CONCISE AS IT CAN BE MADE WITHOUT RISK OF 

MISUNDERSTANDING? Are there any excess words, phrases, or ideas in the statement which are 

not necessary to communicate the meaning of the statement? Are there so many caveats in the 

statement that the statement itself is trivial, confusing, or ambiguous? 

7) IS THE STATEMENT FREE OF SCIENTIFIC OR OTHER BIASES OR IMPLICATIONS OF 

SOCIETAL VALUE JUDGMENTS? Is the statement free of influence by specific schools of 

scientific thought? Is the statement also free of words, phrases, or concepts that have political, 

economic, ideological, religious, moral, or other personal-, agency-, or organization-specific values, 

overtones, or implications? Does the choice of how the statement is expressed rather than its specific 

words suggest underlying biases or value judgments? Is the tone impartial and free of special 

pleading? If societal value judgments have been discussed, have these judgments been identified as 

such and described both clearly and objectively? 

8) HAVE SOCIETAL IMPLICATIONS BEEN DESCRIBED OBJECTIVELY? Consideration of 

alternative courses of action and their consequences inherently involves judgments of their feasibility 

and the importance of effects. For this reason, it is important to ask if a reasonable range of alternative 

policies or courses of action have been evaluated? Have societal implications of alternative courses of 

action been stated in the following general form?:

 "If this [particular option] were adopted then that [particular outcome] would be expected." 

9) HAVE THE PROFESSIONAL BIASES OF AUTHORS AND REVIEWERS BEEN 

DESCRIBED OPENLY? Acknowledgment of potential sources of bias is important so that readers 

can judge for themselves the credibility of reports and assessments. 

B-10
Mr. Rich Poirot 

EPA NAAMS Implementation Proposal, Review Comments, R. Poirot, 12/12/04 

Generally, this is a very strong, carefully considered, well justified and timely proposal. Many 

revisions are directly responsive to previous CASAC Subcommittee review comments. 

Emphasis on use of continuous methods – for multiple, collocated PM & gaseous precursor 

species, and de-emphasis on filter-based PM 2.5 and speciation is a resource-efficient means of 

supporting multiple monitoring objectives, including compliance determination, improved 

atmospheric model development & evaluation, and human health, ecological and welfare effects 

research. 

1. The CASAC has expressed its support for the Agency’s proposal to redesign the 

routine PM monitoring network to support PM precursor gas measurements (CO, 

SO2, NO/NOy, NH3, HNO3) at NCore Level II multiple-pollutant sites, and for air 

quality management decisions and to obtain relevant exposure data for research 

programs. Given limited budgetary resources, does this represent both an 

appropriate and adequate balance, as reflected by the relative resource allocations 

provided in Section 11, “Draft Implementation Plan” of the Final Draft NAAMS 

Document? In addition, are the relative adjustments in the training and guidance 

approaches proposed in the draft implementation plan consistent with the overall 

objectives of the Strategy? 

The question illustrates what seems to me to be a rather proscriptive emphasis on a specific suite 

of “precursor gasses” which is difficult to evaluate without additional detail on the specific siting 

criteria and on the other “required” or optional measurements at these sites. Regarding siting 

details, the general Level II formula (1/state, 2/state in moderately large states, 3/state in the 

largest population states, and 12 rural) sounds to me like it will be a very predominantly “urban” 

network, and that in addition there would likely be just 1 site per urban area in almost all cases. 

These many “1 per city” sites have limited value for supporting ecological effects research, for 

enhancing understanding of atmospheric chemical processes, for model development and 

evaluation, and for some of the proscribed gasses (like NO, CO & NH3) questionable value for 

characterizing regional spatial patterns. Urban site locations for highest human exposures of 

ozone, PM2.5 and some of the proscribed gasses differ by pollutants. So exactly what kind of 

“representative” sites are we looking for? On a related point, the inclusion of detailed met 

instruments is obviously desirable with all this continuous data, but what scale(s) of 

representation are we looking for in the met measurements, and will or should this further effect 

the siting criteria? 

Regarding the other species measurements, I assume at minimum these include continuous ozone 

and PM2.5. Will there also be filter-based speciation measurements, and if so will the new 

measurements be added at existing STN sites, or will those “trends” sites be moved to the new 

optimized multi-pollutant sites? How exactly will continuous PM2.5 mass be measured? Ideally 

a single common method would be employed, rather than the current mix (all things being equal, 

I’d suggest the FDMS TEOM, as it provides higher resolution information (separate volatile and 

non-volatile), and may often capture volatile species partially lost from FRM filters). 

B-11
Continuous (high sensitivity) SO2 is highly desirable, but the value of such data would be hugely 

enhanced if collocated continuous SO4 were also measured. NOy is useful (especially at rural 

sites), but could be substantially more useful if accompanied by continuous hydrocarbon 

analyzers. Aethalometers (especially the dual wavelength – with its potential value as a wood 

smoke monitor) could provide useful information with currently available, field-proven 

technology, and/or continuous OC/EC (Sunset Labs for example) look promising. Will any of 

these continues PM species measurements be included, or do we measure only the precursors? 

The proposed monthly integrated NH3 and HNO3 measurements would substantially enhance 

the status quo (almost no data), but would obviously provide minimal temporal resolution 

(assuming the technologies work). A possible alternative or supplemental approach might be 

through routine extraction of denuders at STN and IMPROVE sites. See additional detail on this 

under question 3 below. 

2. Does the Subcommittee have additional suggestions for addressing this need for 

integration and communication to the broader community of “users,” including 

scientific researchers (i.e., human health, atmospheric, ecological) and State, local 

and Tribal (SLT) Agency representatives? More specifically, what is the most 

effective manner for EPA both to reach-out to this broad user community and, 

where appropriate, to incorporate their feedback and design input on such issues as 

monitoring site locations and parameters? 

Generally, the above “user communities” (human health, atmospheric, ecological, & SLTs) are 

very disparate groups who don’t very often interact. Also, the most relevant health and 

ecological effects issues tend to vary on a regional basis, making “centralized” communication 

awkward. One organizational concept that might be worth considering is to organize periodic 

workshops on a regional basis, as there tend to be clustered integrated user communities who 

focus on specific urban health effects or rural ecological effects monitoring/research sites. 

Examples of the latter from my region include the Vermont Monitoring Cooperative at Mt. 

Mansfield/ Underhill, VT, Hubbard Brook, NH, Harvard Forest, MA & Whiteface Mtn, NY 

(unfortunately none of these is likely to become a Level II site, and I’m concerned my Underhill, 

VT “SIP” IMPROVE site may also be on the NCore chopping block). About 15 years ago, the 

International Air Quality Advisory Board of the IJC held a series of workshops on “Integrated 

Transboundary Monitoring” at 5 locations along the US/Canada border, which were very wellattended and productive. Possibly something like this might be considered on an EPA regional 

basis or through the Regional Planning Organizations (RPOs). 

3. One of the remaining technical issues relates to harmonizing rural- and urbanbased PM2.5 chemical speciation networks such that both categories of networks 

utilize consistent sampling and analysis protocols. For example, EPA is considering 

converting all of the Speciation Trends Network (STN) speciation sites to 

Interagency Monitoring of Protected Visual Environments (IMPROVE) samplers 

and IMPROVE laboratory and sample handling protocols. What are strengths and 

weaknesses of this approach? 

B-12
Spatial & urban/rural consistency alone are good reasons to consider this, with the added 

advantages that (I think) IMPROVE analytical, shipping & site operator costs are lower (though 

the new equipment costs would be significant and STN “trends” - for some species – would be 

disrupted). 

What exactly is meant by IMPROVE methods? Samplers, filter media, “identical” copper anode 

XRF systems, TOR carbon methods – which are currently being revised in IMPROVE, etc? If 

IMPROVE PESA measurements for H are duplicated by STN, only a very few labs have that 

capability. 

IMPROVE is cited in the EPA Strategy as serving as a “core rural speciation trends network: 

needed network adjustments are handled effectively through IMPROVE Steering Committee”. 

While I generally agree here, it should be cautioned that being a core rural speciation trends 

network is serendipitous, but not an objective of IMPROVE, which is intentionally focused on 

regional haze-related aspects of aerosols in specific class I areas, and in recent years specifically 

focused on supporting the EPA Regional Haze Rule – which emphasizes long-term trends. 

Consequently there is added inertia to change, or for adding supplemental measurements to 

address non-haze-relevant issues. 

Also, given the general tendency for class 1 areas to be located in mountainous terrain, the 

IMPROVE monitoring objectives to measure regional rather than local aerosols, and to cover 

each class I area (with funding constraints limiting sites to 1 per area), the IMPROVE network 

tends to provide a “mountaintop” definition of rural speciation patterns. Caution is needed in 

comparing urban sites to nearby rural counterparts (for example Washington DC to Shenandoah 

NP) since we don’t know how much of the DC “urban excess” (at 16 meters ASL) results from 

Shenandoah (1100 m ASL) being often above the mixed layer – especially during winter. I 

emphasize this to point out a need for some rural low elevation sites – which would also be of 

benefit to IMPROVE, and might be best managed by adding lower elevation IMPROVE sites in 

a few class 1 areas. 

As the number of filter-based speciation sites is reduced, and as methods changes are 

contemplated, I think it’s possible that we might “think smarter” and squeeze additional 

information out of the remaining sites. For example, the Canadian NAPS speciation program 

(see brief summary from Tom Dann pasted at the end of my comments) measures more or less 

everything we do at IMPROVE and STN sites, and by fairly similar methods to ours. But in 

addition they denude for HNO3, SO2 and NH3 (STN does not do NH3 but should) and get (I 

think) better quality NH4 data than STN does. Then they extract and analyze their denuders to 

get HNO3, SO2 and NH3, averaged every 3rd sample day concurrent with the aerosol species. 

This is less desirable than the ultimate goal of continuous, but way better than monthly means. 

The Canadians also conduct additional analyses (on Teflon filters) for several organic ions 

(oxalate, formate, acetate), which in turn have proven extremely valuable for source attribution. 

Another difference in the Canadian protocol is that samplers are run 8AM to 8AM, rather than 

midnight to midnight. If loss of volatiles is a concern, this seems like a much more intelligent 

& efficient way of minimizing filter losses (during sampling) compared to the costly STN 

requirements to ship exposed filters in iced coolers. 

B-13
Another example of outstanding “value added analysis” from existing (& expensively collected) 

filter samples is in the recent molecular carbon analysis Ted Russell’s group at GA Tech has 

conducted on archived, composited quartz (carbon) filters from selected Eastern US STN and 

IMPROVE sites – followed by CMB analysis using source profiles developed with similar 

analytical methods. I’d like to see something like this conducted routinely (yearly with seasonal 

compositing), for at least a subset of remaining STN & IMPROVE sites. 

On a related topic, the stated emphasis on data analysis in the NAMS proposal is much 

appreciated – although as usual, the funding level is minimal. A novel approach would be to 

develop a reasonably detailed data analysis plan in advance of conducting new measurements – 

and use it as a guide to what should be measured where, rather than just assuming “here are some 

key species and sites from which we’re bound to learn something”. 

An aside on this, is recent (5 minutes ago) note from our colleague Husar on his latest revisions 

to the “Combined Aerosol Trajectory tool”, which links aerosol data from the entire IMPROVE 

and STN networks (through the end of 2003) to associated back trajectories (ATAD model run 

by Kristi Gebhart at NPS) and allows all kinds of extremely powerful single and multi-site 

analyses – and is also really fun! (once you get the hang of it). Check it out at: 

http://webapps.datafed.net/dvoy_services/datafed.aspx?page=KittyC 

This RPO-supported (with assistance from EPA) analysis tool is I think an excellent example of 

the kind of data analysis that should be routinely funded as a key component of NAMS. 

4. As EPA implements the National Ambient Air Monitoring Strategy to address 

multiple monitoring objectives, it will be looking to spatially optimize the ambient 

monitoring networks. This may mean that some redundant monitors in adjacent, 

but separate, geopolitical areas (e.g., neighboring counties) are “divested” from a 

given network. Although technically sound, these divestments could result in data 

gaps which might, in turn, adversely impact regulatory decision-making. The 

Agency is willing to adopt alternative approaches for assessing regulatory issues 

such as non-attainment designations, so long as such approaches are scientifically 

justifiable; hence, the rationale for initiating discussion of these issues with the 

CASAC. Question: Is it scientifically acceptable to generate air quality surfaces 

through modeled observations and/or integrated predictive/observational fields that 

would be of appropriate uncertainty for use in the regulatory decision-making 

process? 

It has a stronger scientific basis than the current alternative of assuming each political 

jurisdiction is represented by the single monitor within it. I think much could be learned by 

efforts to develop and refine this king of “observation-based model”, and at some point it may be 

appropriate to use such methods to determine compliance status. A goal would be to push toward 

applying such techniques in near-real-time. 

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Attachment 1: Summary of Canadian PM-2.5 Speciation Sampling 

(for more details contact Tom.Dann@ec.gc.ca) 

Fine Particle Speciation Program 

Sampling Equipment and Field Operation 

Sampling sites will be equipped with R&P Partisol-Plus 2025-D sequential dichot particulate 

samplers along with R&P Partisol Model 2300 Speciation samplers. These units share common 

software and data storage systems. The speciation sampler uses Harvard designed Chemcomb® 

cartridges which employ honeycomb glass denuders and filter packs with Teflon and Nylon 

media. 

Both samplers have sequential sampling features and up to 32 fine and coarse filters (16 

sampling days) can be preloaded in the dichot Partisol while up to 12 Chemcomb cartridges (3 

sampling days) can be preloaded in the speciation sampler. At this time, the protocol will be to 

operate the samplers once every three days and to visit the sampling sites at least once every six 

days. Samples will be collected over 24 hours. One fine and one coarse filter sample will be 

collected on the dichot Partisol sampler and three Chemcomb cartridge samples will be collected 

with the speciation sampler as described below. The Chemcomb cartridges are shipped to the 

field completely assembled and sealed and require only mounting and leak-checking. 

Field data sheets will be required but all instrument operating data will be downloaded to Palm 

data systems (provided) and the RAM cartridges will be returned to Ottawa with exposed 

samples. 

Sample Types and Target Analytes 

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Mr. George Allen 

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Dr. Judith Chow 

December 13, 2004 

To: Fred Butterfield, Designated Federal Officer, 

Clean Air Scientific Advisory Committee (CASAC) 

From: Judith C. Chow, Research Professor, Desert Research Institute 

CC: Phil Hopke, CASAC Ambient Air Monitoring and Methods (AAMM) Subcommittee 

Chair 

Subject: CACAS AAMM Subcommittee Charge on the Evaluation of the Final Draft of the 

National Ambient Air Monitoring Strategy (NAAMS) document dated April 2004 

The staff of the Office of Air Quality Planning and Standards did a remarkable job of assembling 

the final draft National Ambient Air Monitoring Strategy (NAAMS) document and responses to 

the 164 comments in the Addendum of the Strategy document. Conceptually, the NCore strategy 

represents a major change from what has been done over the past 30 years. Its success or failure 

will depend on building flexibility into, while establishing consistency within, the current 

monitoring network. EPA is facing major challenges in coming years to assure that data from the 

restructured NCore network will achieve the objectives for compliance and implementation of air 

quality standards, air quality forecasting, atmospheric processes research, and the determination 

of health, visibility, ecological, and radiative effects. The following review focuses on the four 

assigned questions, with additional comments on NCore siting, Level 1 sites, and measurement 

methods. 

Question 1. Given limited budgetary resources, does this represent both an appropriate and 

adequate balance, as reflected by the relative resource allocations provided in Section 11, 

“Draft Implementation Plan,” of the Final Draft NAAMS Document? In addition, are the 

relative adjustments in the training and guidance approaches proposed in the draft 

implementation plan consistent with the overall objectives of the Strategy? 

Table 11-3 listed the proposed redistribution of Federal resources for ambient monitoring. It is 

difficult to evaluate resource allocation without adequate background on how these estimates 

were formulated. It would be helpful to document the cost-estimation basis in categories of: 1) 

initial hardware procurement; 2) initial installation and shakedown; 3) initial training; 4) spare 

parts; 5) repairs; 6) normal operations labor; 7) rent/power/security; 8) quality control and 

auditing; and 9) data processing and management. Based on my calculation, the allocation is 

estimated on an average of ~$60,000 per Level 2 NCore site, including capital investments for 

equipment purchases and associated operating expenses, and $50,000 to $100,000 per Level 3 

NCore site, depending on whether ~1,000 or 500 sites are planned. (Richard Scheffe’s 

presentation and Figure 4-1 show >500 Level 3 sites. But Section 4.3.5 [p. 4-10] shows ~1,000 

sites.) Even if one factors in the infrastructure of the Level 2 site as being mostly established, 

resource allocation to the Level 3 sites seems high. This defeats the objectives of the Level 3 

sites, which focus on a subset of criteria pollutants (e.g., PM and O3). 

While the training and guidance approach proposed in the draft implementation plan is consistent 

with the overall objectives of the Strategy, the resource allocation seems low. Given a total of 

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$198.85 million (note that there is an error in the proposed budget sum), the allocations of 1.6% 

($3.2 million) to quality assurance (QA) and 0.1% ($200,000) to training are low, even though 

they are additions to the current budget. 

The performance evaluation program (PEP) in Table 7-3 estimates $3.6 million in QA— $0.4 

million higher than the Table 11-3 estimate, of which ~60% is allocated to PM2.5 PEP and 

speciation. Listings of the current State and Tribal Air Grant (STAG) fund ($2.3 million in Table 

7-3 and $1.9 million in Table 11-3) are also different. What about QA for existing PM10, future 

PMcoarse, newly added HNO3 and NH3, and NOy measurements, and audits for meteorological 

measurements? Even though some of the training and QA needs arising from the network 

modification may be embedded into each pollutant category, the level of effort needed for QA 

and training (probably at multiple locations) seems to be underestimated, especially for the first 

2–5 years, during the transitional period. 

The certification program is a good approach for ensuring consistent data quality. More detail is 

needed on traceability from common primary standards, to transfer standards, and to in-station 

QA standards. This is especially important for the non-standard measurements (e.g., PM, NH3, 

NOy). There is a need for guidance to clearly state the corrective action for sites that fail to pass 

the certification tests. More centralized QA, as recommended by the CASAC NAMS 

subcommittee, with consistent, clearly stated data validation criteria and data formats, is a good 

target. 

It is encouraging to see “data analysis and interpretation” listed as a separate line item, even 

though it accounts for only 1.1% ($2.2 million) of the total budget. If funding is available for 

data analysis, a detailed data analysis plan is needed to specify data analysis objectives that 

analyze pollution characteristics and trends, identify episodes, explore seasonal/annual trends 

and spatial variations, develop control strategies, track progress of control measures, estimate 

source attribution, as well as evaluate emissions inventory and air quality models (Chow et al., 

2002a). These analyses should be the tools that identify the needs to further refine the network to 

meet multiple objectives (U.S. EPA, 1997a). 

What Table 11-3 lacks (which may be embedded in network operations) are resources for 

different levels of data validation. In the long run, it is more cost-effective to replace filter-based 

measurements with in-situ continuous monitoring. The initial cost of the switch-over is high, and 

continuous instruments are more labor-intensive in the field for routine calibration and 

maintenance, and in the office for processing and evaluating short-term average (1- to 5-minute) 

measurements. Substantial effort is needed for timely data validation to resolve data outliers and 

to take necessary corrective actions to minimize the generation of additional invalid or suspect 

data. Four levels or categories generally apply to validation of monitoring data (Chow et al., 

2002b): 

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Level 0 Raw data right off the instrument (used for real-time alerts and 

forecasting). 

Level I Routine checks made during the initial data processing and generation of 

data, including proper data file identification, review of unusual events, 

review of field data sheets and result reports, instrument performance 

checks, and deterministic relationships. 

Level II Tests for internal consistency to identify values in the data which appear 

atypical when compared to values of the entire data set. 

Level III Comparison of the current data set with historical data to verify consistency 

over time. Tests for parallel consistency with data sets from the same 

population (region, air mass, period of time, etc.) to identify systematic 

bias. This level can be considered as part of the data interpretation or 

analysis process. 

Note that Level III, and possibly Level II, data validation are part of the data analysis and 

interpretation process and may be grouped to the data analysis categories and allocated as 

Research and Development rather than as monitoring funds. While it is desirable to have data 

available soon after its collection—and real-time monitors permit this on a local basis—current 

regulations requiring “submission to EPA 90 days after the calendar quarter in which the sample 

was collected” are reasonable. This allows state and local agencies to conduct Levels 0 and I data 

validation and to perform cross-comparisons to remove invalid data and flag suspect data. 

The zero sum approach is challenging during the transition period since substantial costs may be 

incurred for equipment procurement, operator training, and comparability testing (to retain 

continuity with previous data). I disagree that a data validation protocol should be developed by 

the modeling community (p. 26, response to Comment 127 of the Addendum). For advancement, 

data validation protocols should benefit from lessons learned from those who conduct the field 

measurements; modelers are not necessarily familiar with these measurements. 

Question 2. Does the Subcommittee have additional suggestions for addressing this need for 

integration and communication to the broader community of “users,” including scientific 

researchers (i.e., human health, atmospheric, ecological) and State, local and Tribal (SLT) 

Agency representatives? More specifically, what is the most effective manner for EPA to both 

reach out to this broad user community and, where appropriate, to incorporate their feedback 

and design input on such issues as monitoring site locations and parameters? 

The Strategy formulates several good means (i.e., fact sheets, quarterly newsletters, 

presentations, and brochures) for public outreach. However, from the public comment process (p. 

9-4), it is clear that less than ~10% of the local and state and 30% of the regional offices 

responded during the comment period, with only two comments each from the public interest 

groups and industry, and one from the tribes. It appears that it did not call enough attention to 

those agencies that would be directly impacted by the proposed Strategy, and the 164 questions 

raised may not be representative of the general population. More aggressive solicitation of 

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comments is needed from the research community or data users in the field of atmospheric, 

health, and ecological sciences. One good approach might be to put a notice on popular real-time 

web sites (e.g., AIRNow) where people go to make decisions based on air quality data. 

The majority of epidemiological studies rely on data from long-term compliance networks for 

exposure assessment (Vedal, 1997). A need still exists to broaden the involvement of air quality 

and health researchers to optimize the restructured national network while meeting the current 

resource constraints. 

If additional support can be obtained, the research community can assist in developing data 

validation protocols, conducting data analysis, and evaluating the representativeness of the 

NCore sites. As pointed out by Demerjian (2000), there is a need to develop appropriate 

feedback between the measurement community and data analysts to assure data quality and data 

applicability. This feedback should also cover additional data management issues, such as data 

and metadata items and report formats to facilitate data analysis and interpretation. 

Question 3. What are the strengths and weaknesses of converting all of the Speciation Trends 

Network (STN) speciation sites to Interagency Monitoring of Protected Visual Environments 

(IMPROVE) samplers and IMPROVE laboratory and sample handling protocols? 

The lack of consistency between the IMPROVE and STN networks is a major shortfall, since the 

two networks use different requirements for sample archiving, field blank collection, shipment, 

blank subtraction, carbon analysis (Chow et al., 2001, 2004), and uncertainty estimation (NRC, 

2004). Converting all STN sites to IMPROVE sites has the following advantages: 

Data consistency: A national approach is needed for field sampling, laboratory 

analysis, and sample validation to ensure the consistency of data 

quality. Switching STN over to the IMPROVE protocol would 

minimize the discrepancies between the two current networks. This 

will allow model comparison and evaluation between urban and 

non-urban areas. Archived samples in the IMPROVE network have 

been shared with the research community in the United States and 

foreign countries or to be stored for special studies. 

Cost savings: IMPROVE samplers have been proven to be robust and easy to 

operate since 1987-88. Recent modifications have further advanced 

their utility. With the exception of capital investment for 

IMPROVE samplers, the operating cost for STN following the 

IMPROVE protocol can be substantially reduced. Approximately 

80–90% of the current STN network uses Met One speciation 

samplers (Met One Instruments, Inc., Grants Pass, OR), which are 

labor intensive for filter loading and unloading. Shipping costs 

could also be substantially reduced due to the stainless steel 

housing of the Met One sampling cartridge. The pros and cons of 

cold shipping requirements in the STN but not the IMPROVE 

network also warrant further evaluation. 

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Long-term value: More than 100 publications have used IMPROVE data to evaluate 

measurement systems, map spatial distributions, develop and apply 

source apportionment models, and make important control strategy 

decisions (e.g., Malm et al., 1989; Pitchford et al., 1999). The 

IMPROVE network is just completing the baseline period required 

by the regional haze rule (U.S. EPA, 1999; Watson, 2002) and 

cannot experience major changes without substantial comparability 

testing. The STN has no such requirements. 

Question 4. Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

Currently, network assessment starts at the national level. It uses interpolating methods between 

measurements sites and uses error analysis to remove redundant sites. This type of spatial 

analysis is adequate for flat terrain with a sufficient number of sites. It also works to evaluate 

whether one site is redundant with other sites. It cannot extrapolate concentrations into areas 

with insufficient monitoring. A good illustration is the IMPROVE network, where the addition 

of Midwestern sites in 2001 revealed a large nitrate cloud that was not evident from the earlier 

network. Integrated predictive/observational fields with adequate uncertainty estimates outweigh 

any single modeling approach. Relying on modeled results alone may bias the decision-making 

process. 

As pointed out in a recent National Research Council (NRC) report (NRC, 2004), the enhanced 

network should have the following three characteristics: 1) use continuous measurements of 

appropriate indicators with real-time access; 2) represent less uniform micro- and middle-scale 

exposures; and 3) encourage the development and use of continuous monitors for indicators 

other than mass concentration. For areas that may have concentration gradients between the 

Level 2 or 3 sites (i.e., not representative of micro- or middle-scale exposure), additional 

monitors may be needed. In these cases, dense spatial monitoring (e.g., Chow et al., 1999, 

2002c) over a short period of time (e.g., 2–4 weeks) is needed to add or remove sites, to assure 

adequate spatial coverage, or to confirm observational or diagnostic modeling results. The “zone 

of representation” experiments could be economically executed with portable instruments (e.g., 

Fujita et al., 2003). Their lower precision is still adequate to determine large spatial gradients. 

Instrumentation used at Level 3 sites should be required (not “strongly encouraged”, as stated on 

p. 4-10) to be collocated with filter-based measurements for a set period of time to ensure 

equivalence or comparability. Current requirements for the PM2.5 Federal Equivalent Method 

(FEM) are: 1) collocated precision of 2 μg/m3

 or 5% (whichever is larger); 2) linear regression 

slope of 1 ± 0.05; and 3) linear regression intercept of 0 ± 1 μg/m3

 and correlation coefficient (r) 

of 0.97 (U.S. EPA, 1997b). For Regional Equivalent Monitors (REM), the proposed performance 

criteria are bias (relative to a filter-based Federal Reference Method [FRM]) ± 10%, collocated 

precision (continuous monitors) <10% of coefficient of variance (CV), with r of 0.93. These 

criteria are too stringent to be met for currently available PM speciation monitors. I disagree with 

relying on vendors to demonstrate equivalence (p. 20, response to Comment 92 of Addendum) 

since comparability between instruments varies by location due to changes in emissions, 

meteorology, and aerosol composition. There are only limited comparisons that can be supported 

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by vendors. Depending on the complexity of the surrounding environment at Level 3 sites, 

equivalence, comparability, or predictability (Watson and Chow, 2002) between the testing 

instrument and the FRM should be established at each location for realistic comparison. Methods 

with acceptable comparability should be allowed to facilitate the network transition. Level 3 sites 

should also be used to understand the impact from source-oriented location (e.g., Zhu et al., 

2002a, 2002b) and concentration gradients between the Level 2 sites. 

The Strategy document calls for multi-level network assessment every 5 years (Section 5). It 

appears that a top-down approach is taken in that the national assessment is conducted prior to 

regional or state/local assessment. In addition, the zero-sum approach is at the national level. 

What will the incentive be for state/local agencies to voluntarily reduce their sites, consequently 

cutting off their 103 grants and possibly having to reduce staffing? Is the Regional Assessment 

Guideline Document that is expected to be completed by September 2004 (p. 5-6) available? 

Were consistent statistical methods used at different levels of assessment? Step 3 in the 

Statistical Analysis (under Section 5.4, Guidance for Future Regional Network Assessment) and 

examples found at http://www.epa.gov/ttn/amtic/netamap.html are helpful, but specific criteria 

are needed for national consistency. 

Additional Comments 

NCore Siting 

U.S. EPA Guidance for Network Design and Optimum Site Exposure for PM2.5 and PM10 (U.S. 

EPA, 1997a) defines the following steps for community-oriented core sites and optional 

community monitoring zones (CMZ): 1) locate emission sources and populations; 2) identify 

meteorological patterns; 3) compare PM concentrations; 4) adjust CMZs to jurisdictional 

boundaries; and 5) locate sites. These criteria should be considered for NCore siting rather than 

relying on an “NCore design committee” (p. 4-12). 

It is not clear how “Nearly 80 ‘representative’ air quality regions that group populations based on 

statistical geographical factors ...” (p. 4-11) were formulated for epidemiological studies, and 

how “24 rural locations” were selected to support Community Modeling Air Quality System 

(CMAQS) model evaluation. A total of 75 NCore Level 2 sites ranging from rural to urban areas 

across all 50 states appears to be inadequate for human exposure assessment. In addition to 

population density, source emissions, terrain features, and meteorological characteristics should 

be factored in. A drastic reduction of speciation sites without adequate analysis of the chemical 

composition data at the existing sites seems premature. Sites with long-term historical databases 

and stable infrastructures are valuable for trend analyses and network design. 

Level 1 NCore Sites 

Much emphasis was given to the importance of Level 1 sites, but resources are insufficient. I do 

not believe that Level 1 sites should be operated by EPA contractors or academia, or only for 

short-term durations as suggested in the Strategy document (p. 4-7). One of their goals should be 

to demonstrate how new instrumentation might be used at Level 2 sites. Investment to be made 

in Level 1 sites, such as instrument procurement, trained operators, and the establishment of 

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information technology for data transfers, requires a long-term commitment. For example, the 

Fresno Supersite began operating around mid-1999 and has continued to be operated by the 

California Air Resources Board (ARB) for more than 5 years. Several vendors, government 

agencies (e.g., Battelle’s Pacific Northwest National Laboratory), and academia (e.g., University 

of California, Davis; University of California, Berkeley; and Brigham Young University) have 

benefited from using the Fresno Supersite sampling platform for method testing and for research. 

Concurrent epidemiological studies (i.e., FACES, Fresno Asthmatic Children’s Environment 

Study) have been conducted by taking advantage of 5-minute average continuous measurements 

and 24-hour integrated chemical composition data acquired at the Supersite. As stated on p. 4-15, 

Level 1 sites should be an integral long-term network component and operate with greater intersite consistency. Therefore, Level 1 sites should follow the same data validation and data 

submittal criteria, and should be inclusive of Level 2 site’s measurements. 

Measurements at NCore Sites 

Inconsistent NO or NO2 measurements have been listed throughout the Strategy document that 

need to be clarified. I question the utility of month-long averaged NH3 and HNO3 measurements. 

What kind of denuders can accommodate such a wide range of concentration levels for NH3 and 

HNO3 without breakthrough? HNO3 is a very unstable gas and might shift its equilibrium state 

with particles under high temperatures. What will a month-long measurement or 12 samples per 

year at 75 locations represent? Ideally, these measurements should be an integral part of the 

speciation sampler. Or, at a minimum, they should be collected on a 24-hour basis corresponding 

to one or several of the 24-hour speciation samples to understand the gas-to-particle relationship. 

In fact, shorter averaging intervals (~1 to 3 hours) are desired for precursor gases to better 

understand the gas-to-particle equilibrium under different temperatures and relative humidities. 

These measurements may be considered as part of short-term special studies. 

To facilitate the transition from filter-based speciation measurements to in-situ continuous mass = and chemical measurements (e.g., SO4

=

, NO3 , carbon) requires a collocated comparison to 

ensure the equivalence or comparability between the measurements (Fehsenfeld et al., 2003). 

Recent comparisons (e.g., Drewnick et al., 2003; Fine et al., 2003; Weber et al., 2003; Harrison 

et al., 2004) show that commercially available instruments still need to be modified to 

demonstrate equivalence or comparability. 

References 

Chow, J.C.; Watson, J.G. Guideline on speciated particulate monitoring; prepared for U.S. EPA, 

Research Triangle Park, NC, by Desert Research Institute: Reno, NV, 1998. 

www.dri.edu. 

Chow, J.C.; Watson, J.G.; Green, M.C.; Lowenthal, D.H.; DuBois, D.W.; Kohl, S.D.; Egami, 

R.T.; Gillies, J.A.; Rogers, C.F.; Frazier, C.A.; Cates, W. Middle- and neighborhoodscale variations of PM10 source contributions in Las Vegas, Nevada; JAWMA 1999, 

49(6), 641-654. 

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Chow, J.C.; Engelbrecht, J.P.; Watson, J.G.; Wilson, W.E.; Frank, N.H.; Zhu, T. Designing 

monitoring networks to represent outdoor human exposure; Chemosphere 2002a, 49(9), 

961-978. 

Chow, J.C.; Engelbrecht, J.P.; Freeman, N.C.G.; Hashim, J.H.; Jantunen, M.; Michaud, J.P.; de 

Tejada, S.S.; Watson, J.G.; Wei, F.S.; Wilson, W.E.; Yasuno, M.; Zhu, T. Chapter one: 

exposure measurements; Chemosphere 2002b, 49(9), 873-901. 

Chow, J.C.; Watson, J.G.; Edgerton, S.A.; Vega, E.; Ortiz, E. Spatial differences in outdoor 

PM10 mass and aerosol composition in Mexico City; JAWMA 2002c, 52(4), 423-434. 

Chow, J.C.; Watson, J.G.; Chen, L.-W.A.; Arnott, W.P.; Moosmüller, H.; Fung, K.K. 

Equivalence of elemental carbon by thermal/optical reflectance and transmittance with 

different temperature protocols; Environ. Sci. Technol. 2004, 38(16), 4414-4422. 

Demerjian, K.L. A review of national monitoring networks in North America; Atmos. Environ. 

2000, 34(12-14), 1861-1884. 

Drewnick, F.; Schwab, J.J.; Hogrefe, O.; Peters, S.; Husain, L.; Diamond, D.; Weber, R.; 

Demerjian, K.L. Intercomparison and evaluation of four semi-continuous PM2.5 sulfate 

instruments; Atmos. Environ. 2003, 37, 3335-3350. 

Fehsenfeld, F.C.; Hastie, D.R.; Solomon, P.A.; Chow, J.C. Chapter 5: Gas and particle 

measurements, in Particulate Matter Science for Policy Makers, A NARSTO Assessment, 

Part 2; NARSTO: Pasco, WA, 2003, pp. 5-1-5-37. 

Fine, P.M.; Jaques, P.A.; Hering, S.V.; Sioutas, C. Performance evaluation and use of a 

continuous monitor for measuring size-fractionated PM2.5 nitrate; Aerosol Sci. Technol. 

2003, 37(4), 342-354. 

Fujita, E.M.; Watson, J.G.; Chow, J.C.; Zielinska, B.; Islam, M. Demonstration PM Study Plan 

for Pune, Maharastra, India; prepared for U.S. Environmental Protection Agency Office 

of International Affairs; Desert Research Institute: Reno, NV, 2003. 

Harrison, D.; Park, S.S.; Ondov, J.; Buckley, T.; Kim, S.R.; Jayanty, R.K.M. Highly time 

resolved fine particle nitrate measurements at the Baltimore Supersite; Atmos. Environ. 

2004, 38(31), 5321-5332. 

Malm, W.C.; Pitchford, M.L.; Iyer, H.K. Design and implementation of the Winter Haze 

Intensive Tracer Experiment – WHITEX, in Transactions, Receptor Models in Air 

Resources Management, Watson, J.G., Ed.; Air & Waste Management Association: 

Pittsburgh, PA, 1989, pp. 432-458. 

National Research Council of the National Academies. Research priorities for airborne 

particulate matter: IV. Continuing research progress; The National Academy Press: 

Washington, DC, 2004. www.nap.edu. 

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Pitchford, M.L.; Green, M.C.; Kuhns, H.D.; Tombach, I.H.; Malm, W.C.; Scruggs, M.; Farber, 

R.J.; Mirabella, V.A.; White, W.H.; McDade, C.; Watson, J.G.; Koracin, D.; Hoffer, 

T.E.; Lowenthal, D.H.; Vimont, J.C.; Gebhart, D.H.; Molenar, J.V.; Henry, R.C.; 

Eatough, D.A.; Karamchandani, P.K.; Yang, Z.; Seigneur, C.; Eldred, R.A.; Cahill, T.A.; 

Saxena, P.; Allan, M.A.; Yamada, T.; Lu, D. Project MOHAVE, Final Report; U.S. 

Environmental Protection Agency, Region IX: San Francisco, CA, 1999. 

U.S. EPA. Guidance for network design and optimum site exposure for PM2.5 and PM10; EPA454/R-99-022; US EPA, 1997a. 

U.S. EPA. Revised requirements for designation of reference and equivalent methods for PM2.5 

and ambient air surveillance for particulate matter – final rule; Federal Register 1997b, 

62(138), 38763-38854. 

U.S. EPA. 40 CFR Part 51 – Regional haze regulations: Final rule; Federal Register 1999, 

64(126), 35714-35774. 

Vedal, S. Critical review – Ambient particles and health: Lines that divide; JAWMA 1997, 

47(5), 551-581. 

Watson, J.G. Visibility: Science and regulation; JAWMA 2002, 52(6), 628-713. 

Watson, J.G.; Chow, J.C. Comparison and evaluation of in-situ and filter carbon measurements 

at the Fresno Supersite; J. Geophys. Res. 2002, 107(D21), ICC 3-1-ICC 3-15. 

Weber, R.; Orsini, D.; Duan, Y.; Baumann, K.; Kiang, C.S.; Chameides, W.; Lee, Y.N.; 

Brechtel, F.; Klotz, P.; Jongejan, P.; ten Brink, H.; Slanina, J.; Boring, C.B.; Genfa, Z.; 

Dasgupta, P.; Hering, S.; Stolzenburg, M.; Dutcher, D.D.; Edgerton, E.; Hartsell, B.; 

Solomon, P.A.; Tanner, R. Intercomparison of near real time monitors of PM2.5 nitrate 

and sulfate at the U.S. Environmental Protection Agency Atlanta Supersite; J. Geophys. 

Res. 2003, 108(D7), SOS 9-1-SOS 9-13. 

Zhu, Y.F.; Hinds, W.C.; Kim, S.; Shen, S.; Sioutas, C. Study of ultrafine particles near a major 

highway with heavy-duty diesel traffic; Atmos. Environ. 2002a, 36(27), 4323-4335. 

Zhu, Y.F.; Hinds, W.C.; Kim, S.; Sioutas, C. Concentration and size distribution of ultrafine 

particles near a major highway; JAWMA 2002b, 52(9), 1032-1042. 

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Mr. Bart Croes 

U.S. EPA’s National Ambient Air Monitoring Strategy Implementation 

December 15, 2004 Consultation Meeting 

CASAC AAMM Subcommittee Review Comments, Bart Croes 

Overall, the Strategy document represents a welcome initiative by U.S. EPA to rethink the 

nation’s approach to ambient air quality monitoring in partnership with state, local and tribal 

(SLT) agencies. The document provides a thorough description of the ad hoc process that led to 

the current national air monitoring networks, explains why the networks need to be more 

integrated and adaptable to changing needs, and provides a reasonable rationale for the many 

proposed changes. I appreciate the degree to which U.S. EPA has responded to comments from 

the CASAC NAAMS Subcommittee and others. My comments address the four charge 

questions posed by Rich Scheffe in his November 19, 2004 memo to Fred Butterfield. 

Question 1: Given limited budgetary resources, does the network redesign

represent both an appropriate and adequate balance, as reflected by the relative 

resource allocations provided in Section 11, “Draft Implementation Plan,” of the 

Final Draft NAAMS Document? In addition, are the relative adjustments in the 

training and guidance approaches proposed in the draft implementation plan 

consistent with the overall objectives of the Strategy? 

My comments are based on the premise that public health (and welfare) considerations should 

inform the priority and funding allocation for what is measured, and that all measurements must 

have clients that will use the data for their intended purpose. 

The proposed future resource allocation (Table 11-3) has the right order in terms of the relative 

priority of PM, ozone, and TACs. In California, we estimate 400 annual Statewide cancer cases 

attributable to all TACs (primarily diesel PM, benzene, and 1,3-butadiene) versus 6,500 deaths 

per year related to PM2.5 and 640 deaths per year for ozone. PM2.5 and PM10 are responsible 

for the majority of the morbidity effects. The TAC mortality estimate is an overestimate since it 

uses the 95% upper confidence limit while the PM2.5 mortality estimate could be up to three 

times higher because there may not be a threshold. Thus, PM represents 80-90% of the known 

health risk attributable to ambient air pollution and rightly deserves the majority of resources. 

I recommend that U.S. EPA drop the PAMS VOC monitoring requirements entirely, as the vast 

amounts of data collected each summer do not appear to have a client. Data collected in California 

has had very little utility for trend analyses, emission inventory reconciliation, or air quality model 

input and evaluation. A strategy of continuous NMVOC mass measurements (for trends to check on 

the success of control programs and ozone data analysis), and VOC speciation during special studies 

of ozone episodes likely to be used in SIP modeling, is sufficient. This would save at least $10 M 

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that can be devoted to data analysis and interpretation (proposed for only $2.2 M), baseline funding 

of the Level 1 sites, enhancement of the Level 2 sites, and environmental justice-oriented 

monitoring. 

Perhaps the resources ($10 M) devoted to PMc monitoring can be minimized. U.S. EPA and 

SLT agencies have already invested huge resources into the current PM10 and PM2.5 monitoring 

networks. Several states (i.e., California) have State ambient air quality standards for PM10 and 

do not plan to follow U.S. EPA in adopting a coarse particle standard. Surely if a site meets the 

PMc standard with PM10 monitoring data (uncorrected), then there is no need to deploy a PMcspecific monitor at the site. While U.S. EPA has not yet promulgated a coarse particle NAAQS, 

it has released a Staff Paper with a proposed range of possible standards for PM2.5 and PMc. As 

a first-order estimate, data from the existing PM10 monitoring network should be compared to 

the proposed lower and upper ranges of the coarse particle recommendations to determine if the 

potential scope of a PMc monitoring network would be national in scale or restricted to a few 

states. In these likely non-attainment areas, PM10 would primarily consist of the coarse fraction. 

Sites that have collocated PM2.5 and PM10 monitors or SLT agencies that have operated dichot 

samplers (e.g., California) provide more relevant data for this screening analysis. 

The revised Strategy places importance on the Level 1 sites, but needs to devote resources to the 

effort (with perhaps matching funds from SLT agencies and industry). Level 1 sites can serve as 

a test bed for Level 2 instrumentation, and can appropriately by operated by highly trained SLT 

agency personnel. This approach has worked extremely well at the Fresno PM Supersite, with 

operations by the California Air Resources Board and funding from U.S. EPA. Major yearlong 

air quality field studies (CRPAQS, CCOS), atmospheric researchers (BYU, DRI, UCB, UCD, 

UCSD), government agencies (PNNL, U.S. EPA), and a major $7 M health study (i.e., Fresno 

Asthmatic Children’s Environment Study) have benefited from the Supersite. 

The Level 2 sites should include continuous NMVOC (for trends to check on the success of 

control programs and ozone data analysis) and CO2 (for fuel-based emission inventories that are 

a good check on MOBILE and EMFAC). Sites coordinated with health studies should include 

particle counts or surface area to check health hypotheses and because they do not necessarily 

correlate with PM mass like so many PM components. Some of the Level 2 sites should be 

located for special purposes. These include roadway or tunnel sites (to measure the success of 

the motor vehicle control program), sites to document Asian and Saharan dust events, global O3 

trends, and conditions aloft (instrumented buildings). 

Environmental justice concerns need some funding. Screening methods (i.e., low-cost, easy-to-use 

monitoring technologies) should be developed and deployed to assess near-source exposures in lowincome communities and communities of color. Relatively low-cost passive monitoring 

technologies exist for O3, NO2, BTEX, and HCHO, and portable samplers are available for CO and 

PM. These are not FRM-equivalent devices, but should be suitable for screening purposes. 

Question 2: Does the Subcommittee have additional suggestions for addressing 

the need for integration and communication of the NCore Level 2 network to the 

broader community of “users,” including scientific researchers (i.e., human 

health, atmospheric, ecological) and State, local and Tribal Agency 

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representatives? More specifically, what is the most effective manner for EPA to 

both reach-out to this broad user community and, where appropriate, to 

incorporate their feedback and design input on such issues as monitoring site 

locations and parameters? 

It is disappointing to read that only 29 comment letters were submitted on the September 2002 

draft Strategy document, although that does not necessarily reflect poorly on U.S. EPA public 

outreach process. However, as an active member of NARSTO and an attendee at the annual 

conferences of the Health Effects Institute, I am not aware that NAAMS was presented to these 

broad stakeholder communities. Perhaps a more active effort is needed to identify organizations, 

conferences, journals, and other publications where U.S. EPA staff can present the Strategy. 

If it has not already been done, an email list-serve should be developed and advertised on U.S. 

EPA’s monitoring-related websites. I know that Region 9 has a distribution list of SLT 

representatives, and other regions likely do as well, that can serve as a starting point. The listserve can be used to release the final Strategy and periodic guidance documents, and to solicit 

reviews. 

A useful product to circulate widely is the maps and summaries of existing networks contained 

in Chapter 3. A recent effort by epidemiologists at New York University to do national source 

apportionment maps only found one California STN site in AIRS. There are many more sites as 

part of STN, IMPROVE, and other networks, and easy-to-access network summaries with points 

of contact will increase the use of network data. 

Question 3: EPA is considering converting all of the Speciation Trends Network 

(STN) sites to Interagency Monitoring of Protected Visual Environments 

(IMPROVE) samplers and IMPROVE laboratory and sample handling protocols. 

What are strengths and weaknesses of this approach? 

There would be clear benefits from consistent sampling, analysis, data handling, and quality 

assurance protocols for the STN and IMPROVE networks. My group is a major user of 

speciation data for PM SIPs, Asian transport evaluations, determinations of the impacts of 

shipping emissions, atmospheric deposition estimates for Lake Tahoe, etc., and the difficulty of 

combining the two datasets constrains our analyses. I will leave it to my colleagues to advise 

U.S. EPA whether the STN protocols, IMPROVE, or a hybrid should be employed by both 

networks. Whatever the choice, an effort should also be made to develop source speciation 

profiles consistent with the ambient data. 

Question 4: Is it scientifically acceptable to generate air quality surfaces through 

modeled observations and/or integrated predictive/observational fields that 

would be of appropriate uncertainty for use in the regulatory decision-making 

process? 

Model results are not a substitute for measurements as they rely on highly uncertain emission 

inventories. In general, model acceptability criteria allow much greater errors (on the order of 

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30% for ozone) than is acceptable for ambient air monitoring (less than 15%). I doubt the public 

would accept any substitute for observational data to determine non-attainment status because of 

the risk for “gaming” the model. Ambient air quality standards link back to monitoring data, not 

model results used in epidemiological studies. Could satellite data possibly be an alternative 

approach? 

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Dr. Kenneth L. Demerjian 

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Dr. Delbert Eatough 

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Mr. Eric Edgerton 

Response to CASAC AAMM Subcommittee Charge Questions on Implementation of 

National Ambient Air Monitoring Strategy 

Question 1: Given limited budgetary resources, does this represent both an appropriate 

and adequate balance, as reflected by the relative resource allocations provided in Section 

11, “Draft Implementation Plan,” of the Final Draft NAAMS Document? In addition, are 

the relative adjustments in the training and guidance approaches proposed in the draft 

implementation plan consistent with the overall objectives of the Strategy? 

It is difficult to answer the first question without: 1) knowing the fungibility of 103 and 105 

grant dollars; 2) having the criteria pollutant network assessments from the Regions; and 3) 

having an analysis of the PAMS network. The working assumption in Chapter 11 appears to be 

that PM2.5 funds (2nd largest pool) are fair game for redistribution, criteria pollutant funds (by 

far the largest pool) are not and PAMS funds (3rd largest pool) are somewhere in between. 

Given this scenario, except for the inability to fund Level 1 sites, resource allocations seem 

reasonable and adequate. 

The PAMS network is a continuing enigma. On the one hand, it represents a tremendous 

investment and a game attempt to collect high time resolution data for ozone assessments. By 

my tally, the average operating cost for a PAMS site is nearly 375K. Many of the PAMS 

measurements are analogous to what is needed for PM assessment. For example, the experience 

of measuring 50-60 organic species by GC might come in handy when we want to measure 4-5 

ions via IC. On the other hand, there is little evidence the data have ever been used or even 

scrutinized. My recommendation would be to conduct a forward-looking analysis of PAMS with 

the following questions in mind: 1) Can the network be redesigned to serve needs for ozone, PM 

and toxics assessments? and 2) Can a subset of PAMS sites serve as Level 1 NCORE sites? 

Infrastructure at PAMS sites should provide considerable leveraging. Although PAMS is not 

geographically positioned to provide all Level 1 sites, might it not underwrite 3 or 4, if the total 

number of PAMS sites were reduced to 50 or 60? If the answers to these questions is "no", then 

much deeper cuts in the current PAMS funding are warranted. 

Regarding the second question, the QA component will need substantial funding for 

development of standard reference materials in addition to lab and field audits. The training 

component will need substantial funding to ensure the entire chain of data 

collection/management understands the measurement objectives. For the Level 2 sites, a key 

objective will be detection of secular trends, and this will require very careful attention to 

analyzer response in the bottom 10% of the measurement range (5-20 ppb for SO2 and NOy; 

100-300 ppb for CO). 

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Question 2: Does the Subcommittee have additional suggestions for addressing this need 

for integration and communication to the broader community of “users,” including 

scientific researchers (i.e., human health, atmospheric, ecological) and State, local and 

Tribal (SLT) Agency representatives? More specifically, what is the most effective manner 

for EPA both to reach-out to this broad user community and, where appropriate, to 

incorporate their feedback and design input on such issues as monitoring site locations and 

parameters? 

As a long-term solution, analysis of data for Level 1, Level 2 and PAMS sites and publication of 

results in peer-reviewed journals is hard to beat. It might also be worthwhile to convene 

symposia or panel discussions at ISEEpi (International Society of Environmental 

Epidemiologists, not to be confused with International Society of Explosive Engineers). There 

could be a panel discussion at annual SLT monitoring workshops. The panel would include 

recognized experts in the relevant fields and would discuss future monitoring needs and 

opportunities. In the near-term, all data users should be alerted to the NCORE Strategy and 

impending changes, and encouraged to provide feedback. 

Question 3: What are strengths and weaknesses of converting all of the Speciation Trends 

Network (STN) speciation sites to Interagency Monitoring of Protected Visual 

Environments (IMPROVE) samplers and IMPROVE laboratory and sample handling 

protocols? 

Harmonization is seductive; however, I would recommend a thorough analysis of network 

protocols before making a wholesale move to IMPROVE. Clearly, something needs to be done 

about carbon and a switch to the IMPROVE protocol (TOR) makes sense in terms of current 

operational definitions of OC/EC. Not so clear is whether STN measurement technologies and 

sample handling protocols should be replaced. Does either network offer advantages in flow 

control or Dp50 or sample preservation? For various reasons, IMPROVE does not measure 

ammonium ion, an important component of PM2.5 mass, a nutrient species and an important 

counter-ion to nitrate and sulfate. Instead, IMPROVE incorrectly assumes that nitrate is always 

associated with ammonium and that sulfate is always fully neutralized by ammonium (molar 

ratio = 2). We have to do better than this if we are ever going to understand dynamics of particle 

formation, etc. STN, on the other hand, does measure ammonium and does have protocols in 

place to ensure a certain level of data quality. If a change is in the cards, it will be important to 

ensure it doesn't impair current data quality. 

Question 4: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

From a scientific standpoint, you want to bring all information to bear. The key will be in 

understanding uncertainties and properly factoring them into the decision-making process. If 

this can be done, then there are significant advantages to the concept, including better definition 

of attainment/non-attainment areas and potentially accelerated designation/re-designation. While 

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the scientific advantages are obvious, using combined surfaces for regulatory decision-making 

may be a very tough sell to stakeholders. 

Eric S. Edgerton 

12/19/04 

Cary, NC 27513 

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Mr. Henry (Dirk) Felton 

Responses: Dirk Felton, NYSDEC (Submitted 12/14/04) 

Charge to the CASAC AAMM Subcommittee 

Dec 15th 2004 Meeting 

General Comments follow the four questions to the committee: 

1. The CASAC has expressed its support for the Agency’s proposal to redesign the routine PM 

monitoring network to support PM precursor gas measurements (CO, SO2, NO/NOy, NH3, 

HNO3) at NCore Level II multiple-pollutant sites, and for air quality management decisions and 

to obtain relevant exposure data for research programs. 

Questions: Given limited budgetary resources, does this represent both an appropriate and 

adequate balance, as reflected by the relative resource allocations provided in 

Section 11, “Draft Implementation Plan,” of the Final Draft NAAMS Document? In addition, are 

the relative adjustments in the training and guidance approaches proposed in the draft 

implementation plan consistent with the overall objectives of the Strategy? 

No, the proposed extensive PM-2.5 non-attainment areas demonstrate that PM 

monitoring and particularly PM-2.5 speciation cannot be reduced in many areas. 

Additionally, it may be that the PM-2.5 annual and daily NAAQS will be lowered which 

could require additional monitoring resources. This was evidenced after the 

implementation of the 8-Hr Ozone NAAQS. More borderline attainment areas required 

additional monitors and non-attainment areas required additional up and downwind 

monitors. Establishing sites is difficult and expensive and it does not make sense to close 

a site that may be needed a short time later for ozone, enhanced PM-2.5 or PM-coarse 

monitoring. Many of the NCore principles are important and should be gradually 

incorporated into the existing NAMS and SLAMS requirements. 

The training and guidance approaches may be consistent with the strategy, however, it is 

not generally helpful for the monitoring agency staff who need it most. Many of the staff 

who will be operating the newer technologies are located in remote offices without the 

ability to travel or to access many of these information resources. 

2. The implementation plan proposes a series of communication actions to advance the 

NCore Level 2 network, in order to more directly support long-term health effects research and 

provide better support to ecosystem assessments through an increased level of coordination. 

Questions: Does the Subcommittee have additional suggestions for addressing this need for 

integration and communication to the broader community of “users,” including scientific 

researchers (i.e., human health, atmospheric, ecological) and State, local and Tribal (SLT) 

Agency representatives? More specifically, what is the most effective manner for EPA both to 

reach-out to this broad user community and, where appropriate, to incorporate their feedback and 

design input on such issues as monitoring site locations and parameters? 

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State agencies that have non-attainment concerns must be able to select site locations 

based on how they believe they will be able to demonstrate the effectiveness of their SIP. 

This monitoring, which is already aimed at protecting human health must take priority 

over other research monitoring priorities. Health oriented researchers may be interested 

in urban hotspot monitoring while a modeler may be interested in a boundary site or even 

a monitoring location chosen at random. The monitoring objectives and operational 

procedures may be too different for some of these groups to reconcile in one monitoring 

location or in a comparable dataset. 

State and Local Agencies face the very difficult task of operating quality-assured 

monitoring networks consistently for long periods of time. Many research oriented 

monitoring programs are designed to examine a particular issue and then publish results. 

Some of these Science oriented monitoring programs such as CASTNET have 

demonstrated problems in the long term operation of criteria instrumentation. One 

CASTNET site in the lower Hudson Valley expanded to Ozone monitoring. Over time, 

the operation of the instrument was not properly quality assured and the Regional EPA 

office attempted to make the surrounding area non-attainment for ozone because of this 

data. 

It is advantageous for the various monitoring agency, health agency and research groups 

to meet regularly to discuss instrument selection and limitations, data comparability, 

multi-media pollutants public awareness and other issues. 

3. One of the remaining technical issues relates to harmonizing rural- and urban-based 

PM2.5 chemical speciation networks such that both categories of networks utilize consistent 

sampling and analysis protocols. For example, EPA is considering converting all of the 

Speciation Trends Network (STN) speciation sites to Interagency Monitoring of Protected Visual 

Environments (IMPROVE) samplers and IMPROVE laboratory and sample handling protocols. 

Question: What are strengths and weaknesses of this approach? 

The urban IMPROVE study has not been completed and it is not apparent that the 

IMPROVE protocols would be entirely successful in urban environments. For example, 

inlets on IMPROVE sampler are cleaned annually while the STN inlets are cleaned either 

Monthly or after each sample depending on the type of sampler. A better approach 

would be to select the strengths of each network and design a new Nation-wide program. 

Carbon sampling techniques can be drastically improved by minor changes in flow rates, 

filter shipping containers and field procedures. Since the cost of analysis is so high for 

this program, it makes sense to optimize the sampling equipment in an effort to raise the 

quality of the data. 

4. As EPA implements the National Ambient Air Monitoring Strategy to address multiple 

monitoring objectives, it will be looking to spatially optimize the ambient monitoring networks. 

This may mean that some redundant monitors in adjacent, but separate, geopolitical areas (e.g., 

neighboring counties) are “divested” from a given network. Although technically sound, these 

divestments could result in data gaps which might, in turn, adversely impact regulatory decision 

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making. The Agency is willing to adopt alternative approaches for assessing regulatory issues 

such as non-attainment designations, so long as such approaches are scientifically justifiable; 

hence, the rationale for initiating discussion of these issues with the CASAC. 

Question: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

No, ambient data must be used in the regulatory decision making process. This is clear 

from all of the recent cases where ambient data has been used to refute poor model 

performance. Models are developed to work in a majority of usually simplified 

applications. It is difficult enough to verify a model’s overall predictive accuracy but 

impossible to prove that it accurately covers all areas of a domain. Many areas of a State 

or Territory may not fit into the acceptable range of a model and this could not be known 

without actual data. Recent experiences have shown that the EPA is willing to use 

models that are not accurate or verifiable. 

For example, the EPA’s accepted model for use in PM-10 SIP development calculates 

road dust concentration based on the mass emitted from vehicle tailpipes. This model 

was developed for older cars on roads with fewer vehicles than those of today. The 

model substantially over-predicts the amount of vehicle generated PM-10 in dense urban 

areas such as NYC. What is disappointing is the EPA’s lack of concern or attention to 

poor model performance even when it prevents State Agencies from meeting their 

requirements. 

Another example is the EPA’s use of the Urban Excess model which has been 

inappropriately applied in the urban Northeast. The EPA is currently using this model to 

determine the extent of the PM-2.5 non-attainment areas. This model has been applied 

without taking into account actual ambient data, transport, secondary particle formation, 

meteorology or differences among monitoring programs. 

General Comments on the National Air Monitoring Strategy: 

The majority of people on the AAMM board work in the research field and most likely will be in 

favor of the overall NCore strategy. Many of the NCore objectives are worthwhile such as trace 

gas monitoring, a greater emphasis on data and program analysis and a better integration with 

health and multimedia communities. There is more disagreement towards the overall objectives 

of NCore from State and Local monitoring Agencies and perhaps even from the Regional EPA 

offices. I see a greater loss from what is left out of NCore than what may be gained from its 

adoption in its present form. I think the lack of enthusiastic support from some of the EPA 

regional offices stems from their concern that when the spatial coverage of monitoring is 

reduced, they will have a more difficult time responding to public issues and complaints. 

My concerns with NCore include the melding of networks with different design principles such 

as PM-2.5, Ozone and Toxics, the lack of emphasis on sources, characterization, controls and 

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permits and the reduction in State Agency flexibility due to the tightening of SPM (Special 

Purpose Monitor) regulation. The NCore funding strategy was determined by examining Nationwide statistics from AQS Criteria Data. The value of individual State networks or even 

individual sites cannot be examined in this way. What is the value of a PM-10 instrument if it is 

the only one downwind of a permitted facility? What will happen when the PM-10 standard is 

rescinded before suitable PMc stack testing methods are developed. Data from many State and 

Local Agency’s monitoring sites are put into the AQS system even though these sites are not 

Federally-supported SLAMs or NAMs monitors. In NY, for instance, almost one third of the 

Ozone monitoring network operates at State funded Acid Rain sites. Closing these sites would 

not create the funding opportunity that the NCore strategy indicates. 

Many of the positive attributes of NCore can be implemented with less disruption to State and 

Local agencies’ existing monitoring and permit programs. Currently, State and Local monitoring 

programs are evaluated by their respective EPA Regional offices annually. This network review 

should be expanded to include representatives from the National OAQPS office, health officials 

and if the case warrants; scientific specialties, such as atmospheric modelers, deposition 

researchers, the Forest Service, the Park Service, NOAA, etc. The NCore monitoring objectives, 

sampling technologies and operational experience should be available as a resource to the 

stakeholders at these network design meetings. 

Other goals of NCore may be achieved or at least improved upon through simple procedural 

changes. Some State Agencies still upload 1⁄2 of their MDL (Minimum Detection Limit) to AQS 

in place of their concentrations for parameters such as NO2 and toxics. This convention prohibits 

modelers, risk assessors and data analysts from using low concentration data in their analysis. 

Other low cost opportunities to improve low concentration data include lowering span 

concentrations where appropriate, setting up dual range analog outputs, and through the use of 

digital data logging. 

The benefit to the State and Local monitoring agencies from the implementation of NCore is 

supposed to be the flexibility that results from the reduction in criteria monitoring. The NCore 

strategy suggests that 1000 may be an appropriate number of NCore Level III sites operating 

Nationally. When this number is examined as representing the majority of the spatial component 

of monitoring including PM-2.5, PM-10, PMc, Lead, Ozone, NO2 and Toxics, it is apparent that 

there will not be any “surplus” Level III sites available for State and Local Agency specific 

needs. The resources needed to establish monitoring for SIP development, control strategy 

verification, toxics hot spot investigations or investigations of environmental justice are not 

clearly defined in the Air Monitoring Strategy Document. 

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Dr. Rudolf Husar 

Response to the NAAMS Implementation Plan 

Rudolf Husar, CASAC AAMM Meeting, Updated December 17, 2004 

Overall, the NAAMS implementation plan is as good as its parent conceptual plan. It 

has been developed through the same responsive participatory process and it shows. 

The freshness of the implementation plan sounds almost too good. What’s the ketch? 

Actual Implementation? 

Question 0: Is the plan consistent with the NAAMS strategy? 

To a large degree yes. A key implementation issue concerns the realization of the multi-tier, 

monitoring strategy represented by the 3-level pyramid. Implicit in the strategy is that the levels 

will be mutually supportive entities for the characterization of air quality. How will the tiers be 

linked to form a coherent monitoring unit that provides useful, integrated data from the new 

integrated network? 

Question 4: Is it scientifically acceptable to extrapolate observations by physical or 

statistical models? 

Not only acceptable, but a necessity for integrating the multi-tier data. Thus, spatial data 

extrapolation (say from L2 to L3 and below) should be an integral part of NAAMS strategy 

implementation. It should be part of the monitoring process. ‘Smart’ extrapolation schemes can 

now be used to constrain the estimates by the data as well as by physical laws. The derived 

pollution ‘surfaces’ resulting from the monitoring process could then be used for regulatory as 

well as for many other purposes. 

Question 1: Is this implementation plan an appropriate reallocation of monitoring 

resources? 

The bulk of the reallocation makes sense. However, routine network assessment and level 2-3 

data integration need specific implementation plan and line item in the budget. The $$ for these 

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network operation activities could be from reduced PAMS and from the dubious $10M PMc 

monitoring allocation. 

Question 2: How to improve communication with user communities (health, atmospheric, 

ecological) 

By a more open NAAMS process (glasnost) and by closing communication feedback loops. 

Question 3: Should the STN sites be converted to the IMPROVE protocol? IF (Since) the 

STN approach does not show distinct advantages, it would make sense to adopt the IMPROVE 

protocol for all routine speciated monitoring, so urban-rural differences can be reliably 

quantified. 

The implementation plan takes a very defensive posture toward linking with non-NCore 

networks. There are several readily available real-time datasets that could significantly augment 

the NCore aerosol characterization, e.g. ASOS and Satellites. As shown below, the spatial 

coverage of real-time AIRNOW PM25 (~300 stations) and ASOS light scattering networks (1200 

stations) operated by NWS, FAA and DoD would enrich the spatial texture AND the in situ 

characterization 

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Satellites add spatial texture (MODIS, 250m), source identification (smoke, dust) and some 

vertical information. The example shows a superposition of ASOS Bext and 1 km resolution 

SeaWiFS reflectance and Aerosol Optical Thickness during the July 2002 Quebec Smoke event. 

The augmenting the NCore 3-tier pyramid with such data should be encouraged and made 

explicit in the implementation plan. 

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Dr. Kazuhiko Ito 

Revised comments on the NAAMS final draft. 

Kaz Ito, 12/20/04 

General comments: 

I came into this review process rather late (this Final Draft was the first draft I read regarding 

NAAMS). Since most of the decisions regarding the network design have been already made, 

some of my comments may be too late. I will nevertheless provide these comments hoping that 

they may still be useful in the remaining period of implementation as well as in the future 

revision of the Strategy. 

The difficulty of balancing the budget with the most reasonable scientific decisions to redesign the ambient monitoring network is overwhelming, but I was impressed with the level of 

effort and progress made so far. The proposed NCore network is appealing. Its plan to collect 

multi-pollutant data at each monitor accommodates the need of health effects research 

community (such data were often lacking in the past network monitors). I understand that the 

priorities of the state and local agencies are the most important factors in designing the new 

network, but I also hope that the Strategy will take a closer look at the issues and the needs of the 

health effects research community. In the past ten years, many observational epidemiological 

studies utilized the data from these routine monitors, producing valuable inputs into the process 

of setting the NAAQS. It is interesting to note that, while the main motivation to reduce the 

number of monitors for CO, SO2, and NO2 comes from the observation that most of these 

monitors measure levels well below the NAAQS, many of the PM studies in the past ten years 

reported associations with mortality and morbidity at levels well below the NAAQS. I am not 

implying that I am against reducing redundant monitors (I am all for it). I am just suggesting 

that we should do this carefully. I assume that determining the “redundancy” for CO, SO2, and 

NO2 monitors would be much more complicated than for more regional pollutants such as O3. 

Also, it seems that the decisions about the speciation monitors are being made without detailed 

analyses of the new speciation network data (collected so far, 2001-2004). Some specific 

comments related to these issues are given below. 

Question 1: Given limited budgetary resources, does this represent both an appropriate and 

adequate balance, as reflected by the relative resource allocations provided in Section 11, “Draft 

Implementation Plan,” of the Final Draft NAAMS Document? In addition, are the relative 

adjustments in the training and guidance approaches proposed in the draft implementation plan 

consistent with the overall objectives of the Strategy? 

It is not easy for me to assess the adequacy of the balance without knowing the details of 

the process to eliminate a certain fraction of monitors (for example, what reasoning was used to 

reduce non-trend PM2.5 speciation sites from 160 to 80?). Given my limited knowledge on this 

process, the general distribution of budget seems ok to me. 

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Question 2: Does the Subcommittee have additional suggestions for addressing this need for 

integration and communication to the broader community of “users,” including scientific 

researchers (i.e., human health, atmospheric, ecological) and State, local and Tribal (SLT) 

Agency representatives? More specifically, what is the most effective manner for EPA both to 

reach-out to this broad user community and, where appropriate, to incorporate their feedback and 

design input on such issues as monitoring site locations and parameters? 

The Strategy should obtain feedback from the epidemiology/public health researchers 

who have been using the data from these routine monitors as well as those who have been 

involved in setting up their own monitors for epidemiological studies. I do understand that the 

existing and future air monitoring network is not necessarily for epidemiological studies but 

mostly for regulatory and compliance purposes, and the budget and capacity of the SLT agencies 

would determine the type and extent of the change in the network design. However, input from 

the health effects research community should still be useful, especially because so many of the 

observational epidemiological studies relied on the use of data from these routine air monitors 

that were not developed for epidemiological study designs. Monitor site location needs for both 

short- and long-term health effects study designs should be considered. I speculate that many of 

the epidemiologists and public health scientists who have used the routine air quality network 

data are unaware of the changes that are taking place through the Strategy. I would suggest a 

workshop to identify and discuss the issues among the health effects/exposure community. 

Federal Register is certainly not the medium that these researchers regularly seek information 

from. At the NAAMS subcommittee meeting, Dr. Scheffe suggested that Health Effects Institute 

may be a good place to have such a forum, but I think we need to reach a broader list of 

researchers who should be informed on this issue. I know that some of us are even writing grant 

applications (without knowing the changes in the network design) that rely on these air quality 

data. Aside from getting feedback, at minimum, all the current and recent EPA grantees, as well 

as those who have been involved in this type of research should be notified of the proposed 

changes. 

Question 3: What are strengths and weaknesses of converting all of the Speciation Trends 

Network (STN) speciation sites to Interagency Monitoring of Protected Visual Environments 

(IMPROVE) samplers and IMPROVE laboratory and sample handling protocols? 

I think it would be easier to answer this question if we had a good summary of the STN 

data that have been collected so far (2000-2004) so that we could compare various aspects of the 

data with those for the IMPROVE database. The IMPROVE web site has a very good 

descriptive analysis of their data. I haven’t seen a similar analysis for the STN (I am sure many 

of us, including myself, are trying to do this now). So, it is somewhat frustrating to make a 

judgment without sufficient knowledge. With this limitation in mind, the strength of switching 

to IMPROVE protocol would be that we would have one larger database that is measured in a 

consistent way. At the 12/14/04 NAAMM meeting, I learned that they are collecting data using 

co-located monitors with the STN and IMPROVE protocols. We should probably wait for these 

data to be analyzed before we make decisions. 

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Question 4: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

This question is rather general. However, for a specific situation, I think there is always a 

“scientifically acceptable” (the best available, anyway) way to use the modeled data. I assume 

that EPA is referring to the surface depiction of some smoothed data such as Figure 5-1 on page 

5-1 of the NAAMS final draft. In this case, the objective appears to be to identify areas where 

removing existing monitors does not affect the predictive power of some statistics, in this case, 

the 4th highest 8-hr daily maximum average O3 value. The approach taken for the objective here 

seems reasonable. The remaining question would be the model uncertainty associated with the 

interpolation methods. For example, if we used another available method (e.g., kriging) to 

estimate the surface, how much difference does it make? Also, how do you decide on the 

acceptable (tolerance?) level of error? 

At the 12/14/04 NAAMM meeting, I learned that these modeled surfaces were not being 

used for determining monitoring “redundancy” to remove monitors, so I take back my initial 

concern about the application of these models for SO2 and NO2 monitors. I maintain my concern 

regarding the applicability of these models for non-regional pollutants. For regional pollutants 

(e.g., O3 and sulfate), we can generally assume smoothness in spatial variability (except high 

density traffic areas where NO may quench O3). Determining concentration surfaces for PM2.5 

monitors may also be relatively less problematic in areas where spatially homogeneous 

secondary sulfate dominates PM2.5. Estimating concentration surfaces for CO, SO2, and NO2 as 

well as some of the PM2.5 species would be more difficult because they are more strongly 

influenced by primary emissions from local sources, and the monitor-to-monitor correlations are 

much poorer both in terms of temporal correlation and mean levels. The problem with the 

locally impacted pollutants that, if separation distance of two monitors is relatively far (> 20 

miles), then the two monitors having similar average concentrations (or any annual statistics) 

does not necessarily imply that a point between the two monitors would have a similar 

concentration because they may simply reflect separate local sources that do not reach or 

influence concentrations at the mid-point. Thus, the prediction error would be greater for these 

pollutants than O3 or PM2.5 in many of urban areas. I looked at monitor-to-monitor temporal 

correlation for PM10 and the gaseous pollutants in the nationwide data, and found that the overall 

rankings in monitor-to-monitor correlation within the same Air Quality Control Region to be: O3, 

NO2, and PM10, (r ~ 0.6 to 0.8) > CO (r < 0.6) > SO2 (r < 0.5), confirming the larger prediction 

errors for locally impacted pollutants. We will have to deal with this issue for the PM2.5 

speciation data. Some of the PM2.5 species are more locally impacted than others. The 

implication is that differential errors across the PM2.5 species from different source types (e.g., 

regional vs. local pollution sources) will affect source apportionment results and associated 

prediction errors. This issue needs to be investigated using the current trend and non-trend PM2.5 

speciation monitors’ data. Ideally, such information should influence the decision as to which 

non-trend monitors should (can) be removed (for the planned reduction of non-trend monitors). 

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Dr. Donna Kenski 

Response to CASAC AAMM Subcommittee Charge Questions on Implementation of 

National Ambient Air Monitoring Strategy 

Donna Kenski 

Lake Michigan Air Directors Consortium 

December 14, 2004 

Question 1: Are the relative resource allocations appropriate and balanced? 

The allocations presented in Table 11-3 seem mostly reasonable. However, the continuing 

inability to confirm a funding mechanism for Level 1 sites is disturbing. These are an integral 

part of the strategy and must be allotted adequate long-term funding. It is greatly encouraging to 

see a line item for data analysis (two line items, in fact). The data analysis funding for the toxics 

program has been a terrific investment that has and will continue to yield benefits for years to 

come. That said, the strategy’s funds for data analysis and interpretation seem a bit puny for the 

size of the program – even the least generous estimates suggest that a minimum of 10% of 

project funds should be spent on data analysis. Although some analysis will be undertaken by 

SLTs or others, the costs are considerable to plan, perform, and integrate various analyses and 

then make the results web-accessible. Inadequate funding will only leave us with unanswered 

questions and broken or unsatisfactory public access to important data. 

While the decrease in gravimetric PM measurements is justified, and moving to continuous PM 

is advisable, the document doesn’t discuss allocations to continuous speciation measurements, 

except the modest bump-up in CASTNET funds for their 3 pilot sites. These continuous 

speciation measurements are ultimately the most revealing about the nature of PM2.5, and more 

investment on EPA’s part is absolutely critical. These measurements are perhaps best left to the 

Level 1 sites for now, but EPA needs a stronger commitment (financial and political) to 

advancing the state of science of these measurements so that they can eventually be rolled out to 

more sites. Since ORD isn’t supporting this development, perhaps the strategy could take a 

stronger stand. 

Training and guidance adjustments were consistent with objectives; the emphasis on webcasts 

and DVDs should be well received by states. It’s nice of EPA to acknowledge the travel 

restrictions that so many SLTs are subject to. I’m a little skeptical that these types of training 

can really be adequate for some of the more complicated measurements – e.g., NOy. In general, 

while the strategy’s objectives were clear, I have some doubts that the existing technology (and 

the states’ willingness to operate it) are really ready for this broad dissemination. Here again, as 

the strategy notes, EPA/ORD has failed to keep up with the needs of the monitoring community, 

leaving a very large gap between our measurement needs and the technology available 

(commercial or research) to meet those needs. 

Question 2: How can EPA best reach the user community and incorporate their feedback? 

Well...why not just ask them? EPA knows the user community. It’s not that complicated or 

expensive to put together a list of people likely to have something to say on these issues. Put 

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together a short, focused set of questions, or even a draft proposal that gives EPA’s rationale for 

site selection, then get on the phone or email. You are much more likely to get meaningful 

responses if you ask people directly. And don’t forget to ask the stakeholders, too. 

Question 3: What are the strengths and weaknesses of converting STN to IMPROVE? 

From a data analysis standpoint, harmonizing these networks would be a huge improvement. 

The urban/rural signals we’re so anxious to tease apart are hopelessly obscured by these network 

protocol differences. But so many issues are yet to be resolved! Blank correction – to do or not 

to do? What’s the right way? What role do inorganics and the various organic species play? 

What’s the effect of higher mass loadings on samplers designed for clean rural environments? Is 

there a ‘machine’ effect at DRI or RTI – do different instruments yield different results for the 

same protocol? This is not my area of expertise, but since both IMPROVE and STN protocols 

are just that, and the EC/OC measurements are operationally defined, it seems silly to have the 

two major networks be incompatible. We should choose one and be consistent. Even though 

there are many outstanding questions (some of which should be answered by Supersite data and 

other current studies), IMPROVE’s very long and very reliable record make it the obvious 

choice. EPA should make this switch part of the strategy, and get a plan for the transition in 

place ASAP. 

Question 4: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

Of course it is scientifically acceptable to generate surfaces from modeled or observed data. 

Defining ‘appropriate uncertainty’ is more difficult. Our interpolations should be based on a 

fundamental knowledge of spatial variability of a given pollutant. In some cases we have a very 

good understanding of pollutant emissions, dispersion, transport, and the resulting spatial 

variability. But there are serious gaps in our knowledge of other pollutants. We don’t have any 

good idea of NH3 or HNO3 spatial variability across an urban area, so how can we have a 

realistic estimate of modeled uncertainty for such pollutants? And if our modeled PM2.5 

estimates depend on these precursor concentrations, then this uncertainty will propagate through 

a model and perhaps lead to unacceptable uncertainty for decision making. This lack of data on 

spatial variability (particularly on a microscale or in complex terrain) is a data gap that the 

strategy doesn’t really address. There really ought to be some provision for determining spatial 

variability via short term saturation monitoring. 

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Dr. Thomas Lumley 

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Dr. Peter McMurry 

Peter H. McMurry 

University of Minnesota 

December 18, 2004 

Comments on EPA’s plan for Implementing the National Ambient Air Monitoring Strategy 

General Comments: 

a. I compliment the EPA Staff who developed this strategy. They have been responsive to 

previous recommendations by this committee, and have taken the initiative to create a coherent 

vision that extends well beyond specific recommendations of the committee. NAAMS represents 

a clear vision for a measurement strategy that is suitable for the 21st Century. NAAMS will lead 

to more efficient use of the Agency’s resources for carrying out measurements and providing 

access to data. This strategy will play an important role in protecting the public’s health and 

welfare. It has been a pleasure to serve on this committee. 

b. My primary concern with the NAAMS proposal is the lack of a plan for funding Level I sites. 

My arguments in support of Level I sites are listed below: 

• I have been involved in studies of atmospheric aerosols for more than 30 years. During this 

period, the need for instrumentation that would measure, in real time, the composition of 

aerosol particles was clearly understood. With funding from the EPA Supersites program 

(and other programs that focused on airborne particles) in the 1990s, several different 

instruments were developed to enable such measurements. This is terrific progress. 

However, while several such systems are now commercially available, the technologies 

have not yet grown to maturity. Level I sites would enable continued testing of such 

instrumentation. I have no doubt that within the next decade, instruments that can routinely 

and automatic measure the composition of atmospheric aerosols will be available. Level I 

sites will play an enormous role in ensuring that this occurs. 

• State and local agencies prefer to use instruments that operate continuously rather than filter 

samplers, which are more expensive to operate and provide less useful data. Level I sites 

will provide platforms for evaluating the performance of such instruments. 

• Real-time measurements of composition offer the potential to provide much more useful 

information on aerosol composition and at a much lower cost than can be achieved with 

filter samplers. Real-time data is required to evaluate chemical transport models, to assess 

human exposures, and to understand processes that affect size-resolved aerosol composition. 

I am convinced that such data are needed to significantly advance our understanding of the 

effects of atmospheric aerosols (especially their health effects). Level I sites would play a 

substantial role in advancing measurement technology “to the next level.” 

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• Virtually all of the basic research and development on real-time instrumentation for 

measuring the composition of atmospheric aerosols has been carried out in the U.S. Level I 

sites will help to enable this industry sector to grow to world leadership. 

• The measurements that are proposed for Level II and III sites do not include any 

measurements of ultrafine particles (<100 nm) despite the fact that (1) concern has been 

expressed about possible health effects of sub-100 nm particles, (2) planned changes in 

emissions control (especially for diesel-powered vehicles) are likely to lead to significant 

changes in concentrations of ultrafine particles, and (3) recent work has shown that such 

particles can be measured well on a routine basis. Such measurements have been conducted 

for extended periods (more than a decade, in several cases) in other countries, and these longterm measurements are providing extremely valuable information on trends and 

“climatology.” Again, this is a case where the basic R&D was carried out in the U.S., but the 

benefits of that work are largely being realized abroad. 

• One of the greatest scientific challenges is understanding semi-volatile species (i.e., species 

that are present in both gas and particle phases). Important among these are ammonium 

nitrate, and many organic compounds. We cannot currently measure all semi-volatile 

compounds on a routine basis (although techniques for measuring the gas and particle phases 

or inorganics in real time are available.) Organics are an especially challenging problem. 

Level I sites would enable continued work on this problem, which is likely to play a 

significant role in potential health impacts of air pollutants, and which will require more 

work before gas/particle distributions can be accurately represented in chemical transport 

models. 

c. Based on the discussion at our meeting I concluded that realizing the full benefits of NAAMS 

will be hampered by EPA’s organizational structure. As was pointed out by Professors Husar 

and Hopke, it is important that NAAMS data (1) be available in real time, and (2) be easily 

accessed by the public. The presentation by representatives in the Information Transfer and 

Program Implementation Division made it clear that they do not currently plan to establish a data 

access strategy that meets these needs. It appears that the Monitoring and Quality Assurance 

Group is hampered because the Information Transfer and Program Implementation Division is 

not responsive to their needs. This needs to be changed. 

d. Recent studies provide growing evidence that those who live immediately downwind of 

highways are especially likely to experience adverse health effects from air pollutants. The 

NAAMS strategy does not explicitly deal with this issue. Some consideration should be given to 

citing some of the NAAMS sampling stations in locations that would enable long-term studies of 

such effects. 

e. I served as one of three co-chairs on the NARSTO PM Assessment, and I wrote Chapter 11 of 

that Assessment, which addressed needs for further research. I am delighted to note that many of 

NARSTO’s recommendations are included in the NAAMS program. NARSTO 

recommendations that are not explicitly discussed include: 

• The NAAMS proposal makes no mention of any consultations or discussions with 

monitoring agencies in Mexico or Canada. One of the NARSTO recommendations is that 

networks across North America should be “harmonized” to enable the integration of 

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knowledge from ambient measurements, receptor models, chemical transport models as bases 

for air quality management. I recognize that the U.S. cannot dictate to Canada and Mexico 

how they should carry out air quality measurements. However, if they were informed about 

U.S. plans, they would have an opportunity to work in parallel to develop measurement 

programs that are reasonably compatible. 

• NARSTO recommends that we aim to develop methods to assess benefits of emission 

controls to air quality and the linkage to human health and welfare. NAAMS focuses 

primarily on measurement, without explicit consideration given to the use that will be given 

to such data. 

• NARSTO recommends that ASOS and AWOS data be integrated into national air quality 

monitoring programs. Such data are acquired routinely, but not by EPA. The public would 

benefit substantially if such data were included in NAAMS. 

My responses to questions given by Richard Scheffe in his November 19 memorandum are given 

below: 

Q1. Given limited budgetary resources, does this represent both an appropriate and adequate 

balance, as reflected by the relative resource allocations provided in Section 11? 

My primary concern is the lack of a specific plan to fund Level I sites, as explained above. 

Other committee members have expressed other concerns that should be reviewed by EPA. 

Q2. Does the Subcommittee have additional suggestions for addressing the need for integration 

and communication to the broader community of “users.” 

Meet with Mexicans and Canadians to inform them of our plans, in hopes that they would 

establish compatible measurement strategies and data distribution policies. 

Q3. What are the strengths and weaknesses of converting STN to IMPROVE. 

I will defer to others on the committee who are more knowledgeable than I about sampling and 

analysis strategies for these networks. 

Q4. Is it appropriate for EPA to use “models” for identifying non-attainment areas. 

First, it is important to clarify what is meant by a “model.” Is this a full-blown chemical 

transport model (CTM) that includes everything that is known about meteorology, sources, 

transport and transformations of air pollutants? If so, than it would be appropriate that such 

models be used for regulatory purposes. CTMs would also provide useful information on diurnal 

variations, etc., which is typically not obtained from sampling networks used for attainment 

studies. Of course, different models will produce different results, so the choice of models that 

are used for this purpose would be highly controversial. 

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More empirical models that interpolate among data from sparse measurements would need to be 

used with greater care. Such an approach would probably work reasonably well for species that 

are distributed relatively uniformly. However, when species are emitted locally, then such 

interpolations would likely lead to significant errors. 

So, in summary, the use of “models” is needed, but implementing them for regulatory purposes 

will not be straightforward. 

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Dr. Armistead (Ted) Russell 

Review of EPA’s Final Draft National Ambient Air Monitoring Strategy and responses to 

Charge Questions 

Armistead (Ted) Russell 

Georgia Institute of Technology 

Atlanta, GA 30332-0512 

Having read through the new Draft Implementation Plan section of the Final Draft National 

Ambient Air Monitoring Strategy in detail, followed by the whole report, as well as attending the 

AAMM meeting and presentations by EPA, my first comment is that I was pleased to note the 

extent to which the strategy has evolved since our last review, and how they have addressed 

many of the comments provided in the last round. In particular, they have increased their focus 

on monitoring to address issues dealing with environmental endpoints, e.g., health and ecosystem 

impacts. As noted below, there are lingering issues in this regard. Also, I note that they are 

planning on adding more sensitive CO monitors: another plus. There is also increased emphasis 

on analysis. 

In this review, first, the four questions we have been charged are addressed. This is followed by 

a more global discussion and summary. 

Question 1. Given the limited budgetary resources, does this (the redesign) represent both an 

appropriate and adequate balance? Are the adjustments in the training and guidance approaches 

consistent? 

As noted above, I am pleased to see that more sensitive CO measurements will be 

pursued as part of the NCore Level II monitoring as this is important both for understanding of 

PM sources, but also as a marker for the potential presence of elevated concentrations of other 

automotive emission related species. In our recent source apportionment work, we found that 

having SO2, NO/NOy and CO measurements available led to more stable and reliable results 

when conducting PM source apportionment. The gas phase species act to constrain the solution 

space. Further, these measurements can be made at a temporally finer scale than is currently 

being used for the PM speciation. 

In the preamble to this charge, the emphasis was on gas phase measurements. In regards 

to PM measurements, the reduced emphasis (and resource allocation) on FRM PM mass 

measurements is applauded as they help relatively little with understanding the sources and 

solutions of the PM in a region. Continuous measurements help somewhat. However, it was not 

apparent if the continuous measurements are primarily mass or speciated mass measurements. 

Continuous mass measurements still fall short of providing the type of information needed to 

really understand the sources impacting a region and for evaluating source apportionment study 

results. Greater emphasis on semi-continuous speciated measurements by the emerging 

techniques is suggested. Even if this does not cover the full range of species needed to conduct 

CMB-type source apportionment, they will support other approaches, plus provide more 

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information on the atmospheric dynamics. Further, along with the continuous gas-phase 

measurements, one can utilize additional methods for assessing source impacts. Thus, if the 

increased emphasis on continuous methods does not include continuous (or semi-continuous) 

speciated measurements, I would rethink the resource allocation to include this important set of 

measurements, at least in a limited, critical area, approach. This will also lead to identifying the 

appropriate technologies to use elsewhere. 

I would, in fact, go a bit further, and suggest that resources for non-continuous, speciated 

measurements be reduced and those put in to continuous speciated measurements. One could 

still, at a very reduced frequency, still conduct a full suite of speciated, integrated (filter-based) 

measurements for use with CMB-type analyses, and also seasonal detailed OC analysis. I would 

suggest that this source apportionment, along with the continuous gas and PM speciated 

measurements will provide ample information to understand, even better, the sources impacting a 

receptor, and provide much more information to those who might use the data later (e.g., the 

health community). 

The adjustment in training and guidance seems reasonable, though I do not have a good 

feel for the level of resources it takes to effectively address this task. 

Question 2: Does the Subcommittee have additional suggestions for addressing this need 

(communication and coordination with health effects and ecosystem assessment communities), 

including scientific and SLT representatives? What is the most effective manner for EPA to 

reach-out, obtain and incorporate feedback? 

Again, EPA is to be applauded for recognizing this need. However, the document was 

rather vague in how this would be accomplished. I would be more proactive, identifying which 

cities have been the basis for many of the recent health studies, as well as the researchers. Ask 

them, specifically, what they would recommend. (A possible workgroup?) Likewise for 

ecosystem researchers. Also, EPA should address the issue of site representativeness again. The 

Supersite data, and that for other special studies and routine monitoring provides a wealth of data 

to address the questions: How representative is a single site being used for health/ecosystem 

assessments? What determines the representativeness of a site? How should one identify a site 

that is a balance between having an historical record and is most representative of the exposures 

(human/ecosystem) of concern? The issue of site representativeness for use in different purposes 

has not been well addressed, particularly with attention to uncertainties. This is explored further 

in the response to Charge 4. 

Question 3: What are the strengths and weaknesses of this (harmonizing rural and urban-based 

PM2.5 chemical speciation networks, e.g., using the IMPROVE EC/OC method) approach? 

There is no easy answer here. In general, there are a variety of benefits to using consistent 

methods, which usually outweigh some minor reasons for maintaining different approaches for 

different applications. Data analysis is typically much more straightforward with less 

uncertainties (note the word uncertainties, not uncertainty... one deals with the number of 

uncertainties, the other with the total amount of uncertainty introduced) when the measurements 

are conducted in a consistent fashion. On the other hand, there is some value in having two (or 

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more) competing approaches in terms of more readily identifying weaknesses in the other 

approaches, and if there is a known weakness in the approach that is to be adopted. In the case 

of the IMPROVE vs. NIOSH method debate, both have weaknesses. My read is that the case is 

very much open as to which one has greater weaknesses, in particular the consistency of results 

for conducting source tests and the ensuing source apportionments. It would be a mistake to 

adopt one method now if it makes if introduces a greater uncertainty in the analysis of the 

measurements, e.g., if the diesel pm profile is more consistent using one method over the other. 

Thus, it may be premature to switch right now. I have heard that the argument for choosing 

IMPROVE over NIOSH is that IMPROVE has been around longer, and is not willing to change. 

This is the wrong reason to switch the STN approach. EPA should show, and the community 

agree, that IMPROVE has fundamental advantages over NIOSH. Without this, we should not 

switch as that will close, possibly very adversely for future analyses, an important debate. If one 

can develop better source profiles using NIOSH, then NIOSH should be used and vice versa. 

Again, this is an area where the measurement community at large should discuss which method, 

ultimately, is preferred and for what reasons. Absent from this debate should be that one method 

or the other has been around for longer. That should come second. 

In summary, I support harmonization of the methods used, but as an evolution to using 

the best techniques, not as a convenience. 

Question 4: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision making process? 

 Great set of issues arising from this one question! First, however, I would not use 

“modeled” observations in this process. Use simulated concentrations. That will upset fewer 

people. 

Next, should one use purely simulated concentrations? Surely not with today’s level of 

modeling accuracy/reliability. That was an easy answer. However, one could also answer is that 

any worse than relying on a single observation in determining attainment/non-attainment and to 

identify sources viewed as contributing to PM in a region. The measurements are representative 

of a very limited region. This gets back to Question/Charge 2. While an observation showing 

non-attainment very, very strongly suggests that the PM levels in a region are out of attainment 

with the standards, it is less strong for determining attainment! The degree to which the 

observation is below the standard is suggestive as to how confident one is that the region is fully 

in attainment, but it has a limited spatial application to demonstrating that the region is in 

attainment. A number of observations in a single region does provide further evidence to 

determining attainment, but the observations all have limited spatial application and further 

analysis is necessary to support their regional representativeness. 

Thus, this leads to the use of integrated predictive/observational fields as being the 

preferred approach. While there is much work to be done here, this approach will help tackle 

multiple issues. First, it is probably the best way to extend an observation (or set of 

observations) both spatially and temporally, if necessary. Second, it can be used in the process 

of source apportionment (or vice-versa-: source apportionment can be used in extending the use 

of observations). Third, it will help identify uncertainties in the representativeness of the 

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observations at a monitoring location. Fourth, it will produce the type of information that can be 

used by groups identified in Question 2. Thus, this is, in some ways, the silver bullet. However, 

we still do not have the best approach laid out, and the enabling technologies developed (e.g., 

software/hardware environments to provide this information). However, this can probably be 

tackled within three or for years. Such a process should utilize the observations available, both 

in situ and remote (e.g., satellite) and PM modeling (with data assimilation). There should be a 

feed-back loop where the information provided by the integrated system utilizes additional 

approaches to assess the quality of the fields developed (e.g., data withholding, etc.). While this 

may seem lofty, but EPA should set, as a goal, to have a field of source apportioned 

daily/monthly/yearly PM for the U.S. by 2010 (e.g., target PM2.5 and coarse for 2008, with the 

apportioned fields developed by 2010). The work should also include fields of the uncertainties 

in the integrated daily PM levels and, at least, in the annual source apportionments. This should 

be updated on an on-going basis. (Once it is done once, the second time is relatively easy.) If 

the resources were currently available, I suspect this could actually be achieved by 2008 (using 

2006 data). 

I like what was presented at the meeting in this regard. EPA is going the right direction, 

i.e., by developing surfaces using an integration of observations and modeling. They must take it 

one step further, and that is to also calculate uncertainties. Folks who are against using modeled 

concentrations for attainment/non-attainment decisions must realize that at present, we are not 

even being so sophisticated. A number of counties are designated non-attainment without even 

such information, and some are being designated non-attainment even with observations 

suggesting attainment. Let’s put some more rigor in the process, then struggle with the issue of 

whether one should be 95% confident that a county is in/out of attainment to make 

determinations. 

General Discussion. As noted in previous discussion, I am generally pleased with the Draft 

Implementation Plan and their responsiveness to prior recommendations. I am concerned about 

the motivation to move to the IMPROVE approach without further discussion about the 

disadvantages and advantages of the variety of methods. Given that I strongly recommend going 

to more semi-continuous speciated measurements, this may be somewhat moot... instead of 

discussing IMPROVE vs. NIOSH, lets discuss how to do the measurements semi-continuously 

(if that is at all feasible), and the NIOSH vs. IMPROVE attributes as part of that discussion. 

Given that the reason for conducting speciated measurements is to do source apportionment, the 

question to address is which one is best suited to that task. This requires asking (and answering) 

the question which method will provide the most consistent source profiles within a source 

category and is least sensitive to interferences from atmospheric processing. (Difficult 

question... ask the real experts.) 

We were not directly charged with addressing the reduction in the funding for PAMS and the 

allocation of resources directly for analysis of PAMS observations. PAMS data has been 

plagued by both issues of quality and timeliness, and has been badly underutilized. To this end, I 

would devote greater resources to the analysis of PAMS data, at the expense of other aspect of 

PAMS, possibly reducing the coverage (spatially and temporally) of the PAMS network until we 

milk the current PAMS data and understand what the network can really tell us. This will help 

identify the future role of PAMS, and how resources should be allocated down the road. Until 

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we really start using the PAMS data for what it was intended, let’s spend some additional 

resources to do more analysis of what we have with the concurrent reduction in resources 

allocated for producing more unused data from monitoring. 

Question 4 is a very important question in regards to policy and the need to develop the 

appropriate techniques to achieve EPA’s objectives in a scientifically defensible fashion. With 

satellite observations, a much more powerful information technology infrastructure and new, but 

not “reference method” measurement technologies coming on line, there is the possibility of 

being able to estimate air pollutant fields, exposures, and source impacts, much better than can 

be achieved from individual monitoring sites. This includes better identification of 

“exceedences” defined more broadly as not specifically measured, but sufficiently likely given 

the full range of information available. (Determining sufficiently likely will be fun.) Use of the 

full range of sources can reduce the needed resources for pure monitoring, but this requires 

developing the foundation that can undergo scientific and legal scrutiny. This activity will also 

provide a foundation for better forecasting and control decisions. Don’t be shy about tackling 

the set of problems associated with blending observations (of whatever type), model results, and 

other inputs. 

Finally, the NCore Level 1 sites should get funds from sources other than Science and 

Technology as part of the mission of these sites is regulatory, and their operation should not be 

viewed as something that has little relevance to today’s issues. Planning requires knowledge of 

sources, which can come from NCore level 1 sites, as will attainment/non-attainment decisions. 

Using the process EPA has developed to decide high-priority Level 2 sites, one could also locate 

high-priority Level 1 sites, which then would be used, along with more detailed modeling, to 

identify the regional sources. 

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Dr. Jay Turner 

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Dr. Warren H. White 

Initial responses to the AAMM charge Warren H. White, 12/8/04 

Question 1: Given limited budgetary resources, does this represent both an appropriate 

and adequate balance, as reflected by the relative resource allocations ...? 

I think it serves as a model for how to extract maximum utility from given resources. It is a 

thoughtful initiative that has been carefully deliberated, and is well crafted to align the Agency’s 

air monitoring activities with the needs of the coming years. 

Question 2: Does the Subcommittee have additional suggestions for ... communication to 

the broader community of “users,” including scientific researchers (i.e., human health, 

atmospheric, ecological) ... to incorporate their feedback and design input on such issues as 

monitoring site locations and parameters? 

The Agency is already doing very well in this regard, but I might suggest adding measurement 

quality to the list of issues on which inputs are explicitly solicited. I have in mind here such uses 

as epidemiology, where critical information is carried by variations in concentration rather than 

by concentration itself, or source apportionment, where it may be carried by small shifts in 

concentration ratios, or by inter-species correlations. The real data needs of such uses can be 

tricky to express in terms of the accuracy and precision of individual measurements. Of course, 

every researcher you ask will just say “more is better!” And you will have to disappoint them. 

What you learn by asking, though, is what kind of “more” they want; which aspects of 

measurement quality are critical in their contemplated applications. 

Question 3: EPA is considering converting all of the STN speciation sites to IMPROVE 

samplers and IMPROVE laboratory and sample handling protocols. What are strengths 

and weaknesses of this approach? 

“If you want an exact answer, make just one measurement.” That’s the strength and weakness of 

this approach. The core problem is that particulate matter has so many degrees of freedom. EPA 

can simply define one particular measurement as truth, as it did in the PM2.5 FRM, but this 

doesn’t mean that important information won’t later be found in the rejected alternatives, as the 

existence of the speciation samplers acknowledges. 

Any benefit of preserving dual networks would come from understanding their differences, and 

that would require extensive overlap (collocated sampling), laboratory experimentation, and data 

analysis. You have to sort out how often-subtle differences in sampling and analysis interact in 

practice with the varieties of aerosols actually found in different environments. And this has to 

be a sustained effort, if you are interested in trends over time; materials and practices inevitably 

evolve through the years, and the differences can be expected to compound. I think there are 

better uses for the Agency’s limited resources. And absent the considerable resources to do it 

right, running dual networks will yield nothing but problems; you will always be wondering 

whether your differences arise in the atmosphere or the measurements. 

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So I think the strengths of moving soon to the IMPROVE model substantially outweigh the 

weaknesses. With that bottom line, here are some thoughts on specific strengths and 

weaknesses. 

Strengths of IMPROVE sampler: converting would clearly bring more consistency to 

sampling, not just between the networks but also within STN. Moreover, the IMPROVE sampler 

is field-proven and operator-friendly. 

Weakness of IMPROVE sampler: it employs a critical orifice rather than active flow 

control. While flows are measured accurately, they are allowed to depart from the nominal rate 

that yields a 2.5 μm cut-point in aerodynamic particle diameter. Average cut-points lie outside 

the 2-3 μm range in about 1 of 10 samples. 

 Strengths of IMPROVE protocols: there is no good reason for maintaining two noncomparable systems for analyzing and reporting carbon measurements when both use the same 

basic principle, thermal analysis. DRI (the carbon laboratory used by IMPROVE) has invested a 

lot of research into the underlying method, and I trust their fundamental understanding of it. 

Point of clarification: Would “all of the STN speciation sites” include those oriented to SIPs 

rather than trends? If it includes SIP sites, what sort of data quality objectives does the Agency 

have for such trace XRF elements as Lanthanum, Yttrium, Cerium, Samarium, Niobium, 

Europium, Terbium, Hafnium, Tantalum, Gallium, Indium, Tungsten, Iridium, Scandium, 

Antimony, Gold, Cesium, Mercury, and Barium, all of which are currently reported by STN* but 

not by IMPROVE? That is, how will it specify data quality for elements that are rarely/barely 

detectable? 

* Standard Operating Procedures for PM2.5 XRF Analysis, Revision 2, 1/20/2004. 

Question 4: Is it scientifically acceptable to generate air quality surfaces through modeled 

observations and/or integrated predictive/observational fields that would be of appropriate 

uncertainty for use in the regulatory decision-making process? 

Given that both satisfy the relevant data quality objectives, I don’t see any scientifically 

meaningful difference between modeled and measured data. I can’t believe I said that! 

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Dr. Yousheng Zeng 

December 15, 2004 AAMM Subcommittee Advisory Meeting 

Comments on the EPA NAAMS Implementation Plan 

By Yousheng Zeng (AAMM Subcommittee Member) 

Initial comments: December 14, 2004 

Revised: December 20, 2004 

Response to Charge Question 1: 

Based on the NCore Level 2 parameter list in Table 4-1, if these PM precursor gas 

measurements are not required for NCore Level 2 sites, it will leave only PM2.5, PM2.5 

speciation, PMc, and ozone. This will almost downgrade Level 2 to Level 3. 

Considering the usefulness of these measurements co-located with other Level 2 

instruments and only 75 Level 2 sites nationally, I certainly consider it appropriate to 

include these gaseous PM precursors at Level 2 sites. This seems barely adequate, if at 

all. 

By comparing Table 4-1 and Table 4-3, there seem to be some mismatch. Table 4-1 does 

not include air toxic measurements as core parameters for Level 2 sites. However, 

according to Table 4-3, air toxic trends are one of the objectives for Level 2 sites. How 

can air toxic trends be assessed through Level 2 monitor network if air toxics are not 

measured at Level 2 sites? How the measurements for air toxic trends be implemented? 

Response to Charge Question 2: 

My comment for this question is about presentation for communication purposes. I feel 

that the representation of the big picture of the nation’s ambient air quality monitoring 

systems (before and after NCore) is still somewhat confusing. I think it will be helpful to 

describe the landscape of the nation’s monitoring systems before and after NCore, similar 

to the approach used in the EPA presentation dated July 2003 

(http://www.epa.gov/ttn/amtic/files/ambient/pm25/casac/jul03pre.pdf), page 27 (slide 27) 

with further clarifications. Specifically, after NCore, what networks will still be in 

existence? It may be helpful to readers if the nomenclature in the presentation 

corresponds to the names of networks rather than “Core+PM Spec”, “Core Spec”, etc. 

Does everything on the “Future Directions” side of the slide belongs to NCore and there 

are other networks that will be coexist but not shown? 

Response to Charge Question 3: 

It sounds like a good idea. 

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Response to Charge Question 4: 

The context of this question is about divesting “redundant monitors in adjacent, but 

separate, geopolitical areas”. I think this approach is valid in principle; but there may be 

some practical issues to be worked out. Modeled pollutant concentrations are used in 

various regulatory processes from SIP demonstrations to permitting. Particularly in 

permitting, modeled concentrations are used heavily as the basis for regulatory decisions 

regardless of the geopolitical boundary. Some of these permitting decisions bear 

important economical, political, and legal implications. In my opinion, air quality 

surfaces generated based on a network of well placed monitors are not only scientifically 

acceptable, they are better than using observed data from individual monitor(s) to 

represent the air quality of the geopolitical area in which the monitor(s) are located. 

There may be some practical issues to consider: 

• How close should the monitors be to each other to be considered “adjacent” and 

therefore a candidate for divestment? EPA may establish some general guidelines to 

address this issue. This is also a function of uncertainty and reliability/confidence 

level of the model to be used in place of the actual monitors. 

• If a monitor is to be divested, which side of the boundary should maintain the other 

monitor? How will that affect funding? Should the divesting side still contribute 

some financially if they rely on the other side to provide the data for their regulatory 

needs? 

Additional General Comments: 

Data Integration 

There are significant ambient monitoring activities outside of the networks discussed in 

the Strategy. They include special studies funded by State or local agencies and ambient 

air monitoring programs funded by private industries as part of Beneficial Environmental 

Projects (BEP). For example, the Louisiana DEQ recently ordered sixteen facilities in 

the Baton Rouge ozone non-attainment area to monitor Total Non-Methane Organic 

Compounds (TNMOC) and speciated ozone precursors. The initial order requires each of 

the sixteen facilities to install four monitors, i.e., 64 monitors. Although the final number 

of monitors may be less as a result of on-going negotiations, it will still represent a 

significant increase in spatial resolution in the area and the monitoring will go on for at 

least multiple years. 

The data collected by these monitoring activities can be a very good complement to the 

NCore and other monitoring networks covered by the Strategy. The data from many of 

these monitoring programs are not captured in the EPA monitoring data system. The 

EPA should consider developing some mechanism to bring the monitoring data into the 

system. This will be a very cost effective way to improve the spatial and temporal 

coverage. The quality control of these monitoring systems may or may not be as rigorous 

as NCore network. This concern can be addressed by having code flags to indicate data 

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quality confidence level (e.g., a code for NCore, codes for certain types of privately 

funded monitors). In a data analysis, having a mixture of high and low quality data with 

high density spatial coverage is often better than having accurate but sparsely populated 

data. 

Funding for Level 1 Sites 

I agree with many AAMM Subcommittee members concerning the importance and 

funding of Level 1 sites. Reducing PAMS sites in some east and west coastal areas (but 

not in the Gulf Mexico coastal region where ozone problems require high spatial 

resolution PAMS data) to fund Level 1 sites seems to be a good idea. There may be 

another funding source (although I don’t know how to make it work at this time). Based 

on my observations and experience, some monitoring programs required as BEP are not 

well thought-out. Sometimes the pollutants selected for monitoring are not critical. 

Companies implement the monitoring program almost just for the sake of spending 

money required by BEP elements of the settlement without too much concern as what 

will be monitored. As a result, the monitoring data have very low value. It will be 

interesting to investigate if there is an administrative mechanism to channel and 

aggregate this type of BEP funds to support Level sites. 

Atmospheric Processes That Were Previously Masked by High Pollutant Concentrations 

Another comment I have is also related to spatial resolution. As the ozone situation 

improves in some industrialized regions of the country, some previously less known 

factors that have impact in a small area become more salient (i.e., as the overall ozone 

level drops, some previously “buried” peaks will become visible. The ozone formation 

due to highly reactive VOC (HRVOC) in Houston and Baton Rouge in recent years is an 

example of such a condition. My concern is that the network spatial resolution may not 

be high enough if we don’t take these factors into the consideration. 

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NOTICE 

This report has been written as part of the activities of the Environmental 

Protection Agency’s (EPA) Clean Air Scientific Advisory Committee (CASAC), a 

Federal advisory committee administratively located under the EPA Science Advisory 

Board Staff that is chartered to provide extramural scientific information and advice to 

the Administrator and other officials of the EPA. The CASAC is structured to provide 

balanced, expert assessment of scientific matters related to issue and problems facing 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 EPA, nor 

of other agencies in the Executive Branch of the Federal government, nor does mention 

of trade names or commercial products constitute a recommendation for use. CASAC 

reports are posted on the SAB Web site at: http://www.epa.gov/sab. 

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