This is a preliminary summary. It has been placed on the bulletin board for comments and corrections from the Base Programs Analyses and Policies Work Group members. When their review is complete and this summary is in final form, this warning will be removed.

June 18, 1996

Summary June 12, 1996 Base Programs Analyses and Policies Work Group Conference Call

I.	OVERVIEW

The Base Programs work group held a conference call on June 12, 1996 to discuss the issue papers on "Population Weighting of Monitors to More Accurately Represent Personal Exposures" and "Introduction and Implementation of a 'Too Close to Call' Category to Reduce the Impact of Meteorological Fluctuations on Attainment Designations." Other issue papers on the agenda were not discussed because of time constraints.

II.	PARTICIPANTS

Work group:

Jerry Golden-Chair, Joe Paisie-Chair, Vincent Brisini, John Crouch, Richard Chastain, Gregory Dana, Richard Dworek, Steve Gerritson, Rich Halvey, Robert Kappelmann, Dennis Lawler, Arthur Lee, Brock Nicholson, Bob Palzer, Steve Pezda, Jim Salvaggio, Greg Schaefer, Jean Vernet, Chuck Mueller for Herb Williams, and Mel Zeldin

Others:

Beth Friedman, EC/R Incorporated (EPA contractor support)

Work group members not in attendance:

David Baron, Glen Cass, Jeff Gabriel, Richard Phelps, Don Pickrell, Jim Ralston, Conrad Schneider, and Eric Skelton

III.	ACTION ITEMS

1)	On the population weighting issue paper, Jim Salvaggio will provide comments on the description of the current monitoring network, and Steve Gerritson will provide information regarding transport. Jerry Golden encouraged individuals to submit written comments to the authors as soon as possible.

2)	Upcoming Calls and Meetings. The next Base Programs conference call is scheduled for June 26. The group tentatively agreed to a 2-day face-to-face meeting in RTP on July 1 and 2. In addition, the work group will meet On July 29,in advance of the July 30 FACA subcommittee meeting. The CAAAC will meet on July 31. Also, the work group chairs will meet with Coordination Group members on June 21 to discuss process issues. Finally, an Ad Hoc group of the FACA Subcommittee has been formed to try to reach consensus on the Interim Implementation Principles. The principles will not be returned to this work group.

IV.	MEETING SUMMARY

The Chairs introduced Richard Chastain to the work group. He is a representative of the Economics Group and has been asked to follow the activities of the Base Programs work group. He will be present at future calls of the work group.

Population Weighting of Monitors to More Accurately Represent Personal Exposures

Jerry Golden noted he had provided Steve Pezda with additional comments on the background piece to the issue paper.

Brock Nicholson raised a general concern about the use of population weighting from the States' perspective. Mr. Nicholson said that at a recent STAPPA/ALAPCO meeting the consensus (although no formal vote was taken) among the States was that this concept would be very difficult to explain to the public and State regulators, who would perceive the approach as being more protective of people in denser population areas. Steve Gerritson and Dennis Lawler agreed.

Arthur Lee said the issue paper recognizes that exposure is an issue that needs to be addressed. Both Brock Nicholson and Bob Palzer said the negative perception is, nonetheless, difficult to counter. Bob Palzer added that he felt that there is more than just a perception that the population weighting approach would be less protective of people in less dense population areas.

Vince Brisini explained his proposed new option, which is based on averaging monitor values when the monitors are based in the same temporal and spatial air mass. In cases where data from a single, local monitor identify a problem, this data might not be used to address overall ambient conditions, but would still require some action. Jim Salvaggio urged caution in proceeding with an averaging approach because ozone is not just a local phenomenon. Bob Palzer added that averaging might also fail to reflect PM-fine exposure. Brock Nicholson said that averaging would have to be very carefully considered to avoid these problems.

Mel Zeldin shared the concerns about adoption of an averaging option and gave an example of how ozone violations increase from the coast as the air mass moves inland. Averaging would give insufficient weight to inland violations. Mr. Brisini replied that in this example, the air masses are probably not the same, and agreed the data should not be averaged. He provided an example where one monitor shows a violation and another monitor in the same air mass shows no violation. He questioned whether the single violation should mean the entire area is nonattainment.

Mel Zeldin asked how the concepts of Areas of Influence (AOI's) and Areas of Violation (AOV's) would fit into an averaging scheme. Arthur Lee said either population weighting or averaging could merge with the AOI/AOV approach. He stressed, however, his aversion to the use of extreme statistics. Dick Dworek suggested that more monitors should be used to define smaller AOI. However, Jim Salvaggio said that the underlying problem in trying to subdivide areas is that ozone is a regional problem and very few local strategies work. Vince Brisini noted that in the southwest ozone can result from a large local component. Robert Kappelmann agreed there are local effects.

Jim Salvaggio said the issue paper does not accurately reflect the current monitoring network and its use.

Greg Schaefer asked whether high values in a metropolitan area subject to transport represent peak events or merely the aggregate of the air entering the area. Joe Paisie said monitors see a combination of regional background and locally generated ozone. In urban centers, ozone values decrease because of NOx titration. Further downwind, the ozone can rebuild. He explained this is why using data from one monitor without a modeling or geographic perspective is problematic. Mr. Schaefer then said that it seems the issue is about peak sources compared to averaging across a transport region. Steve Gerritson said that averages would not occur over a transport region. Arthur Lee added that population weighting differs from transport. Furthermore, the option does not preclude addressing "high monitors."

There was a discussion of the purpose of the paper and next steps. Dennis Lawler said the paper should lay out options, and felt the discussion was focussing on recommendations. Mel Zeldin suggested tabling the issue paper until the other issues have been concluded. At that time, this issue may no longer be relevant. In contrast, Arthur Lee said the issue needs to move forward. Steve Pezda added that the last section on "other issues" recognizes the concerns raised by other work group members. In response, Brock Nicholson said the strong reservations of the State and environmental sectors needs to be addressed in the paper.

Joe Paisie mentioned that his sense of the group is that two of the three sectors that make up the group do not want to go forward with population weighting and within the industrial sector there is mixed support. He wants the discussion to identify whether there are other options. Steve Pezda and Arthur Lee stressed there needs to be some kind of weighting scheme to address exposure.

Jerry Golden asked Jim Salvaggio to provide comments on the description of the current monitoring network and Steve Gerritson to provide information regarding transport. Joe Paisie suggested consideration of a total exposure option. Following up on a comment made by a member of the public, Joe Paisie also suggested consideration of the idea of using exposure weighting when developing attainment strategies. Vince Brisini said the discussion of averaging should be revised to be closer to his original proposal. He said option 4 should be limited to simple averaging. Other options could be added to address possible combinations of strategies. Joe Paisie noted that the ANPR for the National Ambient Air Quality Standards for Ozone and Particulate matter discusses population weighting and that it should be reviewed with respect to this issue. This ANPR is on the TTN and in the June 12 Federal Register.

Introduction and Implementation of a "Too Close to Call" Category to Reduce the Impact of Meteorological Fluctuations on Attainment Designations

Brock Nicholson provided general comments on the "too close to call" concept. He said if the strategy is based on monitoring results, implementation should not require too much energy. Instead, the form of the standard should drive the process. Alternatively, if the strategy is based on modeling results, Ned Meyers' recent work should be considered. Ellen Baldridge said Ned Meyers' information (Guidance on Use of Modeled Results to Demonstrated Attainment of the Ozone NAAQS, June 1996 and A New Modeled Attainement Test for Ozone) will be available by Friday, June 14 on the SCRAM bulletin board on the TTN.

Jim Salvaggio is concerned that the proposed statistical approach is to difficult to explain to legislators, and he would like to find a simpler approach. David Chock said the information could be presented in the form of a "look up" table and that legislators would be interested in this level of detail on an implementation issue. Mr. Salvaggio disagreed. Mr. Chock and Greg Dana stressed that the strategy should be brought forward based on the best science.

Joe Paisie asked, if the standard included the "within the range of attainment" idea, whether this form would effectively address "too close to call." One member noted that the final form of the standard could differ. In addition, the standard is based on health risk, whereas the issue paper deals with meteorology. Bob Palzer responded that meteorology is a fact of life, and opposed finding statistical ways to dilute a protective, health-based standard.

Dennis Lawler suggested adding options to (1) address "too close to call" through the form of the standard and (2) include Ned Meyers' modelling-based approach. Jerry Golden suggested including the 2/5 standard option and analyzing it to see if it results in a more stable situation than the current form of the standard. Mel Zeldin suggested adding a PM-10 option to address the inherent measurement uncertainty when data from more than one monitor is used. If the resulting measurements are within the range of uncertainty, the results are "too close to call." Bob Palzer said the rounding process already addresses measurement uncertainty.

Joe Paisie asked why the only uncertainty addressed in the current draft of the issue paper is that of meteorology. David Chock said meteorology is the key factor influencing uncertainty.

Jerry Golden suggested revising the paper to move the detailed discussion of the t-test to an appendix and making the body of the paper simpler and more generic.

Bob Kappelmann said he understood the concern of a single outlier driving nonattainment, especially if the outlier is driven by a unique meteorological condition. He suggested the possibility of establishing a transition time to allow for a more in-depth assessment of whether the event was truly an outlier, or whether it was something more typical that should result in a nonattainment decision. David Chock said the purpose of the t-test was to identify true statistical outliers.