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U.S. ENVIRONMENTAL PROTECTION AGENCY

SCIENCE ADVISORY BOARD STAFF OFFICE

CLEAN AIR SCIENTIFIC ADVISORY COMMITTEE (CASAC)

PARTICULATE MATTER REVIEW PANEL PUBLIC MEETING

Marriott at Research Triangle Park

4700 Guardian Drive, Durham, North Carolina

Tuesday, July 27, 2010

(Volume II)

ATTENDEES:

CASAC Members:

Dr. Jonathan M. Samet, Chair

Dr. Joseph D. Brain

Dr. H. Christopher Frey

Dr. Armistead (Ted) Russell

Dr. Helen Suh

Dr. Kathleen Weathers

Consultants:

Dr. Lowell Ashbaugh

Prof. Ed Avol

Dr. Wayne Cascio

Dr. Joseph Helble

Dr. Rogene Henderson

Dr. Philip Hopke

Dr. Morton Lippmann

Dr. William Malm

Mr. Charles Thomas (Tom) Moore, Jr.

Mr. Richard L. Poirot

Dr. Frank Speizer (Telephonically present)

Dr. Sverre Vedal

Science Advisory Board Staff:

Dr. Holly Stallworth

Dr. Vanessa Vu

Office of Air Quality and Planning Standards

Ms. Lydia Wegman Ms. Vicki Sandiford

Dr. Karen Martin Dr. Marc Pitchford

Ms. Beth Hassett-Sipple Mr. Tim Hanley

Dr. Scott Jenkins Ms. Joann Rice

Dr. Pradeep Rajan Mr. Phil Lorang
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I N D E X

Page

Proceedings 254

Discussion re:

Charge Question No. 11 254

Charge Question No. 12 265

Charge Question No. 13 321

Charge Question No. 14 328

Closing Remarks by:

Dr. Samet 347

Dr. Vu 350

Ms. Lydia Wegman 351

Dr. Karen Martin 352
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P R O C E E D I N G S

(8:30 a.m.)

DR. SAMET: Good morning. It's 8:30 a.m., and

the schedule says Reconvene Meeting so we're going to

move on now to the discussion of the Secondary --

Secondary Standard. We'll see where we are and how

much we may be able to get done, just looking at the

text that was sent on to Holly overnight.

So let's see, Karen, does your team have

comments?

DR. MARTIN: No. We covered the overview

yesterday, so we don't have anything to add right

now.

DR. SAMET: Okay. So with that, then, let's

go right on to discussion of Charge Question 11.

And, Rich, I guess you're in the lead here.

COMMENTS ON CHARGE QUESTION NO. 11:

MR. POIROT: I don't have very much to say

about the approach. I think it's been a consistent

approach that the staff has followed from the

beginning.

From the first time we saw this Urban-Focused

Visibility Assessment, it seemed like a logical

analysis of the relatively few available urban

visibility preference studies that led to a
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reasonable-appearing selection of a range of levels

considered unacceptable across a number of different

study areas that didn't focus in on any one range,

but suggested something, you know, between 20 to 30

deciviews would be a reasonable level to consider to

be adverse. And then, using a variety of different

methods to estimate particulate matter related to

light extinction -- actually, a fairly highly complex

method that could be applied in 11 or 14 case study

cities -- and similar approaches are applied in this

version of the Policy Assessment document with a lot

of additions that were responsive to questions that

we had raised the last time.

You know, there are an awful lot of

combinations of different indicators, levels -- I

guess we haven't argued much at all about the

averaging time -- but indicator, levels and forms.

So the information, just to present it and get

it out there, is just inherently very complex; and I

think they've done a really excellent job in

illustrating what these various different

combinations would translate to in terms of standards

that would have different apparent levels of

stringency across the different study areas. So,

overall, I just thought the approach was quite
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rational and well conceived, logically conceived and

clearly illustrated.

I thought in terms of question B: Has staff

appropriately applied this approach in reviewing the

accuracy of the current standard and potential

alternative standards, that's kind of a two-part

question. I thought the first part is really easy to

answer. I think it seems clear, no matter which way

you look at it, that the current standard is not

adequate. The averaging time is too long, the level

is too high, and it's less than directly responsive

to the effects of particulate matter on visibility.

So to me, that part's easy to insert.

In terms of the proposed alternative

standards, several are discussed, including the

preferable -- preferable approach of using a direct

measure of light extinction, which would be ideal,

but perhaps is currently impractical given the

availability of current instrumentation, so on and so

forth, on the one hand. And on the other hand, let's

say the -- simply using a fine mass indicator

averaged over shorter averaging times, and so forth,

would be kind of the other extreme.

And then they proposed an intermediate kind of

a combination, really, of those two things in which
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extinction would be estimated from available

continuous fine mass and speciation and relative

humidity data. So I guess that's the approach. I

think it's clearly illustrated and the options are

reasonably laid out in front of us. I may have some

concerns or some suggestions about alternative ways

of estimating extinction from the available data, but

I think that will come up later.

So that's all I have on the approach, John.

DR. SAMET: Thank you, Rich. Bill?

DR. MALM: I guess I could comment. The

comments I might have -- I guess the essential

comments that I might have are similar for both 11

and the Discussion Charge Question Number 13, which

I'm lead on, so let me say something -- let me make

the general comments now because they're sort of

appropriate for 11 and 13.

I guess the biggest concern that I have is

that there's so many combinations of percentile

levels and different metrics and maximum -- you know,

the one-hour maximum every day versus the one-hour

maximum across all days. And you know, comparing and

contrasting all these different approaches, I mean, I

think you made a -- first of all, it's just amazing

how much work it takes to get all this done and to
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look at all these possibilities and so forth, so

you're to be commended on doing that. It's a lot of

work to get where you are. But I think the next step

is to somehow quantify these different comparisons.

The different approaches, come up with some way to

quantify that so it's easily summarized and one can

understand the advantages and disadvantages of making

one set of choices over another set of choices.

You've talked about how the 90th percentile

all-hour approach is similar, I believe, to the 98th

percentile max one hour every day. I think that's

the combination that you emphasized, yeah. So, and

you say that they compare reasonably well. Well, two

points. What's reasonably well? You know, everybody

has different value judgments when it comes to

statements like reasonably well. So somehow you

should quantify what reasonably well means, and I

think that -- I think that somehow, maybe -- somehow

graphically showing that. I guess the bottom line is

somehow to quantify those comparisons. There are

probably other combinations that are reasonably well,

too -- compare reasonably well, too; but you know, so

what? What's the consequence of those comparisons?

And then secondly, what are the implications

of these different choices? The choice of picking
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the one-hour maximum every day versus the one-hour

maximum for all days. You suggest in there some

place that in one case they're similar, but in one

case you've got two or three hours out of a day

picked for the one approach and, obviously, if you

only allow one hour per day you don't get that for

the other. So that has implications, I would think,

in the kinds of sources that might be emphasized for

control.

And I brought this comment up before. I think

that would be -- and you can't go back and do all the

model runs all over again to explicitly tie this

down; but at least there should be some discussion

about the potential implications of these different

approaches. I mean, if you have one big episode in a

year, I suspect that one big episode is going to be

targeted more than it would be if you picked a

one-hour maximum every day. So the sources that

might be addressed for -- or the states might choose

to address for meeting the standard could very well

be different depending upon what standard you pick.

I think having some discussion and, maybe, pointing

out, if you can't point exactly what those sources

might be, you could at least point out the

implications of one approach over the other.
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So within the context of all that, I think

that some way of quantifying all these different

combinations. And then ultimately, it seems to me,

it would be helpful to have some recommendation as to

what approach you guys think might be more

appropriate because of such-and-such and

such-and-such, and I didn't see anything approaching

a recommendation of why one approach might be better

over another approach. There's so much information,

so much data, it would be hard for anybody to really

read through all that stuff and form that conclusion

on their own. I think you have to help the reader

along and at least point out why you might want to

pick one approach over another and, again, the

implications of that.

So I guess to sort of -- I mean, this

discussion is -- I made similar comments under both

this Charge Question 11 and 13. So that's one, the

one issue.

The second issue, I think maybe it needs to be

in the research section as opposed to being able to

do something in the next go-around, but all these

scenes have something -- people are responding to

similar cues, and it would be helpful to come up with

a visibility -- extinction, deciview, visual range,
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all that stuff isn't -- really aren't visibility

indexes. They're another way of characterizing the

stuff that's in the atmosphere. So if you came up

with a -- you did a great job on developing a logit

model, and it now allows for an easy and more direct

intercomparison of all these different visual air

quality -- the preference studies. You probably also

could come up with a visibility index, and there's

some numbers in the literature -- a visibility index

that would normalize all these scenes such that they

would all fall in the same curve, that these

acceptability curves that are modelled with this

logit model would basically lie on top of each other

if they were plotted against a true visibility index

which characterized the scenic quality or the quality

of the landscape features that these folks are

looking at.

That index obviously would be a -- have some

sort of a nonlinear relationship with extinction and

concentration and all this other stuff, but it would

help if you could do that. Then you basically would

have a metric that could be applied to any scene any

place in the country, or probably the world, for that

matter. And then you could relate that back to

extinction and the kinds of other discussions that
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you need to have in terms of preserving or getting to

some point where that scene is acceptable.

So you probably can't get that done in the

next go-around, but you probably ought to include

something like that in the -- in things that need to

be done because I think it's very do-able and

somebody should give some thought, and maybe I might

even give some thought to it. I think that would be

a big step forward and then a lot of these kinds of

discussions that we're having would go away.

So I guess that's enough for now. Thank you.

DR. SAMET: Okay. So your general comment, I

mean, in terms of, sort of, the number 11, the

current approach, which I think Rich took on in a

more constrained sense when he gave his answer, is

okay; but I think what you're saying is it laid out

this huge array that then becomes difficult to find

your way through. And I think we're going to come

back to it as we discuss 12 and 13.

Lowell?

DR. ASHBAUGH: Yeah. I actually liked the

rewrite very much. I thought you did a very good job

of it.

My primary interest in this was the ten-step

process of calculating visibility reduction. It
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seems to me there's going to be an awful lot of

uncertainty in that that hasn't been addressed, and

in particular, taking the 24-hour daily scaling

fractions, scaling those down to -- averaging them

for the months, scaling them down to the day, and

then applying them to an hourly measurement based on

a continuous monitor. So it's going to wash out so

much detail that I'm not sure you're going to

actually get what's providing viability reduction;

and this isn't even to mention the problems with

using the hourly measured relative humidity, which we

found in the IMPROVE program varies so much that it's

also a difficult process. So I think I like the

concept of this calculation; but the uncertainties

involved in it, I think you need to analyze very

carefully before -- before applying that process.

And I think, too, the direct measurement of

light extinction is -- one advantage that wasn't

stated in the document is that you get immediate

feedback on it. The process of collecting the

filters and analyzing them for speciation and doing

this other analysis takes a considerable amount of

time. The advantage of a direct light extinction

measurement is you've got feedback right now. I

think that needs to be brought out as well.
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That's the main thing I wanted to bring up on

this.

DR. BRAIN: Can I ask a naive question? When

you're directly measuring light extinction, how do

you deal with fog, snow, rain? Just educate me.

DR. RUSSELL: Actually, the instrument would

be designed such that when the relative humidity is

over 90 percent, you're not -- it wouldn't be

measuring. So that immediately gets rid of the -- I

mean, that's actually one of the considerations we've

had before in this group just because of the issues

associated with that.

DR. BRAIN: Thank you.

DR. SAMET: Okay. Other comments on Charge

Question 11, general approach? Tom?

MR. MOORE: I apologize because I wasn't able

to participate in the discussions very well in March.

It seems like we really leapt forward here;

and there's roughly a page on direct measurement,

indicator for optical, and many pages on this

speciated mass and composition approach; and I just

wonder whether that's in balance considering the

comments that Lowell just made about further

developing the optical option.

And I want to second Bill's approach that
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essentially there needs to be, kind of, what are you

recommending, what are you choosing among the

percentiles and the forms and the indicators and why.

I mean, it seems like this standard, consideration of

the standard, requires some staff direction as

opposed to the more low-key terms like, consideration

should be given. I mean, this is really a very

complicated set of choices to make and particularly

when we get to the discussion of the level of the

standard. So I'd second Bill's and like to see a

little bit more on the merits of the optical.

DR. SAMET: I wonder if we shouldn't go on.

We're having a somewhat wandering discussion across

these different charge questions, go on and take on

the nature of the secondary indicator.

Ted?

COMMENTS ON CHARGE QUESTION NO. 12:

DR. RUSSELL: Actually, as I said to Rich, I

think we're already getting there.

So on question 12, it's the nature of the

indicator, and staff has laid out three potential

indicators. One, just using PM2.5 mass directly.

Another one -- and this really came up from

discussions of this group probably almost a year ago,

I think it was, that we would just -- that we'd
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recommend measuring PM2.5 light extinction directly.

It's now quite possible to do that, and there's new

instruments coming available. And the third was, as

mentioned, that we would have a calculated light

extinction using the method that has no shortened

acronym or whatever. And so the question is what are

the attributes of each one, or in terms of staff's

considerations, do we think that they've

appropriately supported them.

And I would first state that my thoughts on

the PM2.5 mass indicator for visibility, the only

thing that it has going for it is it's simple, and

given the -- you know, probably the way to logically

think of this is, first, PM2.5 mass indicator. Then

go to the mass calculated light extinction. And the

thing is, is that there's enough information out

there already that using their mass calculated light

extinction formula, that they can do a better job.

So I think you can almost remove the thought of using

the PM2.5 mass indicator without doing something to

adjust for speciation.

So then you come to the mass calculated light

extinction, and as Lowell has already indicated,

there's, I think, a number of problems with this, is

that it doesn't -- there's so many biases and
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uncertainties in the measurements to begin with.

Then when you start taking these monthly averages and

trying to figure out or apply monthly averages to

what would become one-hour averages, it has some real

problems associated with it; in part, is that the

time of the greatest visibility degradation is when

the relative humidities are high. And it's also when

the relative humidities are high is when you're going

to have the more soluble components, the nitrate and

some of the organic carbon, that would also correlate

with the water content of the aerosol; but those are

also the components that you lose in some of the

filter-based measurements. So you're going to have

this real problem there, is that some of the most

important -- more important species are the ones you

wouldn't be measuring to try to apply in your mass

calculated light extinction. So I think there's just

a lot of issues with the mass calculated light

extinction.

And then when we get to the using directly

measured PM2.5 light extinction, I think the real

pushback there is that people are afraid to use --

you know, that they don't want a new instrument, or

at least I think that's the only -- only reason I've

heard so far that makes any sense. And I would say
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that the instrument technology is there. I think

it's going to be one of the better instruments, more

stable instruments, to have out there, one of the

easiest to use and it's going to give us some

wonderful new information. It's -- and it's going to

be continuous. I think there's just a tremendous

number of reasons to use, to deploy these new

instruments, plus it is measuring exactly what you

want to predict.

So I look at those three and just say of the

three different indicators that have been proposed, I

think there's just so much -- so many reasons to go

for direct measurement, and I think there's enough

reasons to go against the other two that I would rule

those out. Of course, Rich has another idea on that

one.

DR. BRAIN: And the document is not now

explicit enough in making your recommendation; right?

You really want to modify it so it's clear?

DR. RUSSELL: I would be more explicit, yes.

DR. BRAIN: Thank you.

DR. MARTIN: If I could ask a point of

clarification here. In your comments that the

instrumentation is there now, I think we all remember

the AAMM Subcommittee meeting where this was very
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explicitly discussed. And the conclusions that came

from that, from my understanding, were that, while

there is developing instrumentation, we're talking

about some years before it could be sufficiently

tested and developed to provide a basis for a

standard.

DR. RUSSELL: You're talking about the cavity

ringdown approaches, which would be better.

DR. HOPKE: Well, which would get you PM10.

The difference is PM10 versus PM2.5. If we want

light --

DR. SAMET: Phil, use your mic.

DR. HOPKE: -- PM10 then --

DR. SAMET: Microphone, Phil, microphone.

DR. RUSSELL: Speak to your mic.

DR. HOPKE: Okay. If we want light extinction

from PM10 then the instrumentation is not here now.

If we want light extinction from PM2.5, yes, there are

certainly capable instruments that are available on

the shelf now.

DR. RUSSELL: And it would be two different

instruments right now that we would use in tandem,

one doing scattering and one doing absorption.

DR. MARTIN: Okay.

DR. HOPKE: Right.
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DR. RUSSELL: I think that may be what

you're --

DR. MARTIN: To put a finer point on the point

I was trying to make, while you've identified

instruments that are available right now, the Agency

doesn't have established reference methods for --

that have been evaluated and tested for their use as

a reference method for a standard. It was my

understanding that we were projecting that was a

multi-years' effort in order to do the evaluation

work necessary to establish it as an FRM and that

that was a primary issue in this draft in terms of

coming up with an alternative approach because of

that limitation in having an FRM for the purpose of

directly measuring light extinction.

DR. SAMET: So I think we should hear from the

remaining discussants on this point and then circle

back as we need to, to this question.

Joe?

DR. HELBLE: I actually don't have much to add

to what Ted said based on my reading of the document.

I thought it was clear. I thought the three

potential indicators that were discussed were the

appropriate ones. I thought -- and maybe Ted didn't

make this point quite as directly, but I thought
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staff did a nice job of talking about PM2.5 mass as an

indicator and then essentially dismissing it, saying

here is why it's not the ideal choice. So I thought

given that the discussion then became one of direct

measurement versus measurement based on speciated

concentrations, I would -- without commenting on

availability of instrumentation and the time it takes

to develop an FRM -- second the point that any time

you can make a direct measurement, it's preferable.

The time issue that Lowell pointed out, meaning you

get direct feedback here, is certainly a strong

positive; so I would encourage the Agency to move in

that direction.

Having said that, I think there are other

reasons to get better speciated PM2.5 data that

will -- came out yesterday in discussing some of the

research needs, will come out again later today when

we talk about the research needs. So if this could

help develop a more extensive network of speciation

monitoring, I think that would be a positive and have

ancillary benefits. Still, having said that, I think

when the opportunity to make direct measurement is

available, I would strongly urge movement in that

direction. Otherwise, I simply would echo what Ted

said.
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DR. SAMET: Okay. Tom? Tom, yeah.

MR. MOORE: I think it's Bill.

DR. SAMET: No.

MR. MOORE: Okay.

DR. SAMET: You're welcome to comment or not.

MR. MOORE: Oh, I was going to comment, but I

didn't keep track of this one on my list here.

Well, I would like to come at this from kind

of an operational point of view. People have already

made the point about timeliness, and I'm sympathetic

to the issues that Karen has raised. I think in

practice people are running these instruments already

for the direct measurement, and I think that favors

that indicator because I think one thing that happens

in the speciated mass calculation approach is that

you have all these uncertainties and possible

different approaches that folks will use and I'm just

wondering whether that, kind of, anticipates the air

quality planning needs a little bit; and perhaps that

could be dealt with in that step where we have a

simple black-and-white measurement of are you over a

standard or not and then there's a speciated mass

approach to derive what you do about it.

So the objective standard would be simple,

direct measurement, timely. You wouldn't be telling
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people three months later what happened, which is

kind of a less-than-optimum situation. And you know,

you could save all the speciated analyses for the

implementation and do that when you -- for the areas

that required that.

I do want to give credit to the idea of this,

kind of, integrated assessment that was done because

it was nicely written up. It definitely should be

laid out in such a way as an option so that the

Administrator can consider it; and I think that also

could inform this research agenda issue that Joe

started to raise here, too, what do we need to know

if this indicator were selected. So just knowing

that we're over an optical level is nice to know and

so that's a protective effort there; but we're going

to need a methodology that contributes to the

over-all body of knowledge, say, in five years when

the next review is underway.

DR. SAMET: Okay. Bill?

DR. MALM: Question, Karen, is the -- the

method of reconstructed extinction is based on

continuous mass measurements. Is there a federal

reference method for continuous mass?

DR. MARTIN: I'm going to ask our monitoring

folks, or if one of you want to speak to it. Phil?
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MR. LORANG: Since I'm here, let me try. Phil

Lorang from the EPA.

There is a procedure for qualifying continuous

instruments as equivalent and there are a number of

models that have been approved as continuous, but the

criteria for approval is on their 24-hour average

performance. There's no system to ensure that

one-hour values are online -- or in line with what

they might actually be.

DR. MALM: So I guess, I mean, I sort of agree

with Phil in the sense that if it's possible, I mean,

any direct measurement -- there's a number of

instruments out there and any direct measurement is

going to be more accurate than a reconstructed

extinction, period. I mean, that's a slam dunk. I

mean, I think the reconstructed extinction is

adequate for what you want to achieve, but the

instrumentation is there right now to make a direct

measurement more accurately than you could ever

reconstruct it even if you had continuous mass

measurements every hour, so.

DR. SAMET: Okay. Phil, do you want to weigh

in?

DR. HOPKE: Yeah. Again, I'll just chime in

again.
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I mean, we have a lot of experience with

measuring -- with these measurement techniques. I

mean, they've been running nephelometers for a long

time. In IMPROVE network, there's a lot of

experience with nephelometers.

I mean, you know, I don't understand what it

is you're going to try and quantify because how are

you going to generate a known standard atmosphere

with a known standard extinction or absorbance. I

mean, if we could do that, we could actually test the

accuracy of an FRM and discover that it's crap, you

know.

So I don't see what the problem is with years

to get to an FRM. You define it by design like you

have in the past and then develop some equivalence, I

mean, you know. I think you have to get something

going and the simplest straightforward approach is to

have a reasonable nephelometer and absorbance

measurements out there. And again, we can come and

revisit this in the not too distant future if you

want to start moving to, again, more single

instruments, PM10 instead of 2.5. These things may

well be available in five years; but if we think it's

important to start with visibility, it seems to me

that there are opportunities to do that fairly
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effectively and efficiently in the near term.

DR. MARTIN: The reason I'm raising these

points of clarification is, as you all know, in the

first draft of this Policy Assessment this hybrid

type of approach was not discussed. We're talking

about either aggregated mass or light extinction.

The thing that happened between the first draft and

the second draft that caused us to develop this

alternative approach was the meeting with the AAMM

Subcommittee and the discussion that took place there

and the recognition of -- I was not at that meeting,

but my understanding -- and these folks were, so I'll

let others speak more directly to it -- was the

recognition that, while there was instrumentation

that was available and had been used in the past,

there were new methods coming along, that there was

time needed to do some pilot work that would feed

into, and the type of evaluation that the Agency

needs to do to establish an FRM and that we weren't

talking about a year or so. We were talking about

many years. And it was that outcome of that AAMMS

meeting that caused us to come back and say, okay,

right now we have two alternatives, neither of which

for different reasons look like something we can move

forward with in this review. How can we sort of
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split the difference and develop something that we

could move forward with in this review. And your

comments now seem to be somewhat at odds and

surprising relative to what we heard when we met with

the monitoring subcommittee. And I'm sort of -- sort

of wondering what to do with this discussion in light

of that difference.

DR. SAMET: Well, I think Vanessa's going to

comment. Then we might get the other Ted Russell to

comment.

DR. VU: I think Karen did portray correctly.

And Ted -- I know, Phil, you did not participate at

that meeting of the AAMMS.

You did. Oh, that's right, Phil, you did.

DR. HOPKE: I was there, pitching for the same

thing I'm pitching for now.

DR. VU: So maybe what we could do is pull

that report and make it available to everyone to

refresh everybody's memory.

DR. SAMET: Let's see, Ted and then Kathleen.

DR. RUSSELL: I think what we came out of the

AAMMS meeting was saying in the meanwhile you could

use as a bridging approach the essentially

reconstructed visibility, and the recommendation was

you would go to direct measurement and in the
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meanwhile use a reconstructed approach. But the

endpoint was to direct measure it, and that would

give you time to do it.

Now, I can try to pull up the report, but I

think that was our recommendation.

DR. BRAIN: As a bystander, it certainly

sounds like there's less and less confidence in the

reconstruction approach. That's sort of what I hear,

is that it's not a bridge you'd want to walk across.

DR. RUSSELL: Oh, I would actually in the near

future have -- say that it's a reasonable bridge.

It's better than using PM2.5 mass and it's something

that can be done relatively quickly. So I don't have

a problem with that bridge in the meantime. I just

don't want that bridge to be the one that goes on

forever.

DR. SAMET: Okay. Kathleen.

DR. WEATHERS: So this is a very useful

discussion to explain why it is that I was confused

in reading through these indicators. And from 35,000

feet, one of the things that really heightened my

interest in trying to sort these out was the comment

that the choice of the indicator versus the form is

probably more important. So the indicator, what gets

chosen here seems to have a huge influence on the
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outcome looking at the forms and levels and potential

standard.

So it was not clear to me for the second two

choices how many of these variables can be measured

now; so we're discussing that right now. It sounds

as if light extinction, it can't be measured

currently; is that -- that correct, in the field is

not being measured currently.

It was not clear to me from one of the -- the

modeling approach which pieces of information exist

now or whether there has to be some additional

monitoring data, so if you can answer that before I

go on.

DR. PITCHFORD: Okay. I'm not sure I

understood exactly what you were saying, but let me

answer what I think you said and then you can tell me

if I'm right.

DR. WEATHERS: Yeah.

DR. PITCHFORD: Okay. People do direct

optical measurements now, but they don't do them in

the context of any regulatory framework. It's more

to gather different kinds of information or for

scientific things, and they've been doing that for

several decades. So it isn't novel, new things that

are currently available that could be used. But EPA
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does not have -- has not gone through any process.

We've never had this as an indicator, so we had no

reason to do that. So there would be -- even if

everything else was perfect, there would have to be

some effort and whatnot put forward to make it so,

but there's also technical issues that in a

regulatory framework would have to be looked at.

So what AAMMS -- what we thought we heard from

AAMMS was, don't think that you can just take what's

on the shelf now and put it out in the field and use

it. There's a fair amount of work that needs to be

done. And I agree with what Ted said. They did talk

about using some sort of a calculated extinction as a

bridging technique, and that's our leaping off point

for what we did in the Policy Assessment with our

third indicator, so; and everything we need for that

indicator is available.

DR. WEATHERS: Okay. So that's helpful, and

it would be helpful to have that be clearer in this

document as well.

DR. PITCHFORD: Sure.

DR. WEATHERS: What's also not clear is what

the sensitivity of this modeling approach is from a

parsimony standpoint. This is a pretty complicated

model that seems to me rules in a lot of
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uncertainties that aren't identified here, so it

would be really useful to know something about those

uncertainties.

DR. SAMET: Okay. Rich?

MR. POIROT: So I'd like to disagree with all

of my colleagues to a point and start with the

reflecting back on the Urban-Focused Visibility

Assessment where there's a series of the scatter

plots in one of the appendices that compare just

plain old stupid fine mass with the most elaborately

reconstructed extinction. If you look across those

and throw out the St. Louis site -- which had, I

think everyone acknowledges, bad data -- the average

R

2

is point 7. And as a starting point, I'd like to

suggest that there's never been a NAAQS indicator

that related to any effect, primary or secondary

anywhere, that's anywhere in the ballpark of point 7.

That's an incredible relationship right there to

start with.

So I think all of this concern about the

uncertainties, well, they're really not huge, even if

we start in the simple terms of thinking of the fine

mass indicator. If you can bring in the humidity

associated with the aerosols in a reasonable way, you

can improve that point 7 to point 85 or something
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like that. The uncertainties in this reconstructed

extinction calculation, frankly, are not large and

it's not possible for them to be large. So I'm not

anywhere near as concerned that -- as some others

are, that this is going to be fraught with errors and

so on and so forth.

What I'd really like to get us to as an

endpoint of a recommendation, if we could, would be

the idea of pushing as hard as we can for the need

for optical instrumentation as the preferred way to

go, but without pushing so hard that it breaks the

thing and everybody says, oh, then we can't have any

secondary standard this time around. So that's why I

thought that the, sort of, interim use, the mass data

enhanced by speciation, or whatever, kind of a

recommendation that came out of the AAMMS

subcommittee as an interim approach was a good idea.

And I think also, this committee itself said the same

thing in its letter the last time around, that we

recommended as an interim approach using the mass

enhanced with the speciation and humidity data in

whatever ways were feasible, and that's what they

did. So I don't understand why we should be all

upset about them doing what we asked them to do.

So I just would like to try, though, to reduce
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some of the concerns that this reconstructed approach

is going to be way, way out in left field. No, it

isn't. No, it isn't.

And beyond that, I would also like to suggest

that I think you could utilize your speciation data

on an historical basis to come up with either a site

specific or preferably regional composition that you

could do on a seasonal basis and use that in advance

so that you can then combine that historical seasonal

average speciation information with your realtime

fine mass and humidity data to come up with your

estimated extinction. It's a simpler version of

what's been proposed. It would have higher

uncertainties, but they're not going to be that

great; and the advantage would be that you wouldn't

have to wait three or four months after this

instantaneous visibility effect to know what you

thought it was. You'd have it right there. You

could use it in realtime. You could be pointing it

out in your mass calculations and so on and so forth.

Again, what I would really like us to be able

to do is to come out pushing as hard as we can for

the need to move to the optical indicators because I

think if we don't push pretty hard it's not going to

happen. It's too easy to say, oh, we've got other
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issues to work on; but at the same time being

supportive of this reconstructive extinction as an

alternative approach. And as I say, I think it could

be done in a simpler way that would be more timely

and that the uncertainties would not be that large,

and I think that some calculations could probably be

done that would demonstrate that.

DR. SAMET: So just a comment, Karen, you're

going to finalize this Policy Assessment document in

the next three months, four months?

DR. MARTIN: Yes.

DR. SAMET: So we're pretty far down in

reviewing the second draft with a still, sort of,

undetermined -- a broad set of options with I think

still unclear preferences on the part of the

committee. I think I've heard three possibilities.

One is the view that the instruments that measure

light extinction, regardless of whether there's an

FRM or not, are at least ready enough.

Second, that they may not be ready enough; and

if not ready enough, there are two bridges. One is,

I think, the Rich option, which is, you use PM2.5 in

as informative a way as possible, possibly modified

by knowledge of the region in some way. And the

other is your proposal for this speciated index.
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So it seems to me that in having this

discussion and trying to reach an outcome that

indicates some preference, the first point of the

discussion is, in fact, whether the instruments are

ready for prime time, the light extinction

instruments ready for prime time, and can

be recommended. I don't understand the vagaries in

the development of -- the issues of developing the

FRM for this; but it seems like the first point is,

in fact, whether those instruments are ready and

should be given preference. And if not, then there

are some alternatives that would follow, so if we can

try to be a little bit orderly about this. I know

that's a challenge.

Let's start with that point. So maybe we'll

circle back to Ted, Phil, Joe, and anybody else who

wants to weigh in on -- yes, even, Sverre.

DR. SPEIZER: John, could I throw another

two --

DR. SAMET: So who wants to lead off -- or

Lowell.

DR. SPEIZER: This is Frank.

DR. SAMET: So let's just stick to this one

question and try and resolve it. Lowell?

DR. SPEIZER: Yeah. But I wanted to ask --
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DR. ASHBAUGH: Well --

DR. SPEIZER: -- which is, is there a

difference in data captured that's related to

humidity or rain that would relate to each of these

differently or are they all affected the same way?

DR. SAMET: Okay. I'll take that as a

modification of the question on the table.

So Lowell, go ahead.

DR. ASHBAUGH: I didn't get the sense that

this approach being proposed, to do light

extinction -- and I think that's what's missing in

this document. I'm happy with it being used as a

bridge, but not as the final approach, so.

DR. SAMET: Okay. So that fits with the way

I've constructed -- so let's just first stick with

this point.

MR. MOORE: You're doing a good job on trying

to get us to focus.

DR. SAMET: It's hard.

DR. MOORE: Can you restate?

DR. SAMET: The first choice is whether light

extinction is ready to be given preference or not.

And if not, I think we referred to there are two

bridges, and I gather they are bridges on the part of

the Agency while awaiting the determination as to
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whether the light -- or the light extinction is

ready. And I think it was Rich who was saying maybe

PM2.5 by itself is not so bad and that it could be

refined, I think we were suggesting on a regional

basis using -- bring in knowledge of speciation and

then perhaps humidity, whatever else, and then the

proposal for the speciated approach that's included

in the PA. So I still would like us -- and I think

that's a --

DR. MOORE: There remain three choices, just

as the document outlines, measure it directly, use

PM2.5 mass, and do Rich's approach, or do a more

complicated --

DR. SAMET: Right. But we're putting them in

this sort of decision-making algorithm of what this

committee would like to do. So let's just stick to

the first point I started with, and that I think is

this question on where the light extinction

instrumentation stands. And I think I've heard

divergent -- somewhat divergent views. So I want to

circle the table of everybody who might have an

opinion, so anybody who has an opinion on this. I'll

sort of go around.

Helen, do you have thoughts about this, or

knowledge?
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DR. SUH: No.

DR. SAMET: Okay. Kathleen?

DR. WEATHERS: Yeah. It seems to me that if

light extinction can be measured, that's the primary

choice; and if not, doing the bridging approach, it's

the simplest, is the next. And I think that's what

Rich outlined.

DR. SAMET: And Ted, your view on where the

instrumentation stands? I think you've been clear.

DR. RUSSELL: Yes. So it's available.

There's better stuff coming.

It would have to -- as we lined out in the

AAMMS report, I'm pretty sure -- and I hope someone

is bringing it up faster than I've been able to bring

it up. For some reason my computer is just not doing

it quite so quickly -- that that instrumentation for

PM2.5 does exist now. There are some better

technologies coming along.

What we suggested was that it be tested and,

essentially, the modification made such that it could

be used in network form, for one, taking into account

relative humidity less than 90 percent. If all of

that stuff could be readily done, you would perform

some type of field experiment to assess that it is

appropriately used in the network and get it out,
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recognizing that that would take a little amount of

time until we would have a bridging technique.

Actually, you know, what Rich suggested is probably

fine. I'm somewhat compelled by his argument that if

we're looking just for a bridging approach, something

simple is probably good.

DR. SAMET: So, but actually, back to this

point, I thought you had answered the question.

DR. RUSSELL: Then I didn't.

DR. SAMET: Do we need a bridging approach or

not if the instrument is ready; yes or no?

DR. RUSSELL: I think we do. It would be

useful. So I'm going to equivocate. Sorry about

that, John.

I do believe that this is the sort of thing

that there should be some sort of field

experimentation first before we say this is the

technology, give it FRM status and send it out. So

you know, this will take a couple of -- a few years,

a couple years, but I think we do want a bridging

approach in the meanwhile.

DR. SAMET: Okay. Rich?

MR. POIROT: Oh, I forgot the question.

DR. SAMET: So the question is: Are the

instruments ready? Are the light extinction
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instruments ready or do we need a bridging approach;

yes or no? Well, not yes or no, but bridge or not

bridge?

MR. POIROT: Bridge.

DR. SAMET: Bridge. Okay. Kent passes. Tom?

MR. MOORE: So I think I have some evidence,

but I rely upon the folks at the EPA to straighten me

out on this; but I think a number of state and local

agencies use nephelometry to report hourly PM2.5 for

the AIRNow program. So that what they're doing is

they're pulling air through a PM2.5 cutpoint and

measuring light scattering and then back-calculating

on an hourly basis what PM2.5 is. I believe that's

correct; but I mean, that's an operational question.

But the point is the instruments have been in use for

a number of years in exactly this mode. The

absorption is probably a different, more complicated

issue.

I'm torn because of -- in terms of being ready

to go, I'm, you know, reminded of Voltaire, that the

better is the enemy of the good. And so Rich has

proposed a nice, you know, good approach. So I would

just for the purposes of this discussion say let's go

all the way to optical and not try and do the bridge.

DR. SAMET: So you're a non-bridger.
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MR. MOORE: I'm a non -- well, I'm for

optical. I'm not a non-bridger. I mean, that's a

different....

DR. SAMET: Bill?

DR. MALM: There isn't a federal reference

method for nephelometry right now even though there

is instrumentation that could do the job. So I guess

what I would like to see is that it be clearly --

extinction should be used as the indicator. That's a

slam dunk. I think we all agree on that, but maybe

EPA could propose a timeline. I think if you can't

go out with something that doesn't have some sort of

blessing by EPA, then what's the timeline to get that

blessing? What is the timeline to get to a point

where you have a federal reference method that

applies for nephelometry? And in the interim, the

techniques that you guys have proposed, I think,

would work just fine. As Rich pointed out, they're

far better than any other relationship between health

endpoints that we haven't asked for right now. So

maybe just a timeline is all that's needed, is to say

that we're going to use this interim approach up

until now and then we anticipate that we'll have a

federal reference method for --

DR. SAMET: And don't answer timeline yet.
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We're going to complete our round of the table.

Let's see, Mort?

DR. LIPPMAN: No, I pass.

DR. SAMET: Phil?

DR. HOPKE: Okay. The question is, what mass?

Are we going to use the FRM mass? Are we going to

use the continuous monitors so they're adjusted to

get the wrong mass and wind up with the FRM? Are we

going to get a full FDMS where we get something

probably closer to a real mass?

DR. SAMET: You're talking about on the

bridging?

DR. HOPKE: What?

DR. SAMET: You're talking about on the

bridging?

DR. HOPKE: Right. So the problem is that,

you know, at this point we don't have all of the

sites we would want with continuous mass monitors.

Now, I think that would be a great idea. I mean,

that's obviously something I've been pushing for for

a long time. So I think we should be getting rid of

all of our filter units and putting continuous mass

monitors out there. But if we're going to have it

relate then effectively to the visibility, it has to

be a more effective measure of mass and not a measure
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of mass that's trying to meet the FRM; and I think

there's a problem there that needs to be looked at

and addressed.

DR. SAMET: Okay. Phil, in your view on the

light extinction measurement; is it now?

DR. HOPKE: I would, yeah. Light extinction

measurements, you know, that would be my preferred --

if I had my druthers, I'd have a continuous mass

measurement, I'd have a nephelometer, and I'd have an

absorption measurement system at every site. Then

we'd have good mass measurements. We'd have good

extinction measurements, and we can go forward.

DR. SAMET: Okay. Joe?

DR. HELBLE: I'm in Tom's camp. I'm a non --

I guess I wouldn't characterize myself as a

non-bridger, but I would be in favor of moving

directly towards an optical measurement. I guess,

maybe, I'm missing something. Because this is a

secondary standard, I don't see the need for a bridge

to get us there. Why not simply establish the

standard, establish optical measurements as the

method used to meet the standard, figure out what the

timeline is to get there, and then implement the

standard on that timeline? So rather than doing

something intermediate, say, this is where we want to
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be and just move towards it as quickly as we can.

DR. SAMET: Okay. Chris, any views here?

DR. FREY: (Shakes head from side to side.)

DR. SAMET: Wayne?

DR. CASCIO: No.

DR. SAMET: Joe?

DR. BRAIN: I agree with what Joe said. You

know, let's just endorse the direct light extinction

but recognize that it will take a little time to make

it an operational system. But so I think I'm a

no-bridger. I agree with what Joe said.

DR. SAMET: Okay. Ed?

PROF. AVOL: (Shakes head from side to side.)

DR. SAMET: Lowell, do you want to weigh back

in?

DR. ASHBAUGH: Yeah, I'd like to come back in

again after Joe spoke.

I was thinking of the bridge as something that

might be necessary; but as a secondary standard, it's

probably not necessary. We could go directly to a

light extinction measurement and have the EPA just go

ahead and develop that approach. I would also like

to see some development of an approach for continuous

speciation measurement as much as possible because

that's going to tell you where the visibility
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reduction's coming from.

DR. SAMET: Okay. Karen?

DR. MARTIN: Stepping back from what you all

said, I guess the one point I would really like to

offer is, thinking about the statute and what we're

legally required to do, while secondary standards

don't have a specific timeline to be met, neither are

they promissory notes.

In setting a standard, one part of the

definition of the standard is what you are going to

measure and how you are going to measure it in order

to compare to the level of the standard you set.

It's not a fully defined standard to say this is our

standard in terms of X level of light extinction and

in the coming years under this timetable we plan to

develop an FRM that would be used to determine

attainment with that standard. That's a plan for a

future standard, but it's not a fully developed

standard in and of itself. So while I think

everybody here would agree conceptually with that

approach, that doesn't get us to a fully defined

standard in this review; and so we still need to

grapple with, and so what do we do now.

DR. SAMET: So let me just --

DR. MARTIN: In essence, you can't commit the
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Agency to do a research effort in terms of developing

an FRM today and say that's embedded as our standard

as though it will necessarily happen under that time

frame.

DR. SAMET: Right. And I guess that hinges on

whether the current instrumentation is viewed as

adequate and your reference method could be developed

around that or whether this phase of research is

needed that would preclude such development, as I

understand what you have said.

DR. MARTIN: And to speak to that specific

point, I would like to ask Tim Hanley, who was here

yesterday talking about monitoring, to speak a little

bit to our further understanding of the AAMMS

discussion on this point.

MR. HANLEY: Thanks, Karen.

So one of the things that has been mentioned

in the last ten minutes that was pretty much

unanimous when we met in February with the AAMMS was

with regard to whether the Agency should consider a

design-based approach or performance-based approach.

The reason why I bring that up is because it's

been mentioned that the technology's available today.

We agree with that, but there's multiple technologies

available today. And the Agency coming out of that
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February meeting read the AAMMS report, which, again,

was approved by the full CASAC, as, whatever you do,

do not pick one method more or less as the winner.

And I think the subcommittee was pretty clear, in the

long run we're going to be much better off if we have

a performance-based approach that allows cavity

ringdown and other options that might be developed

down the road to enter into the market and be used

for a light extinction standard.

So I mention that because I think the

subcommittee were telling us -- and there are

subcommittee members here if I get it wrong -- that

you know what, we recognize that we want to get to

the right place; but let's make sure we get to the

truly right place, which is, again, using a

performance-based approach.

If the Agency were to go with a design-based

approach, meaning, pick one method, work with that

instrument company and select it and publish that

method, we'd have that; but then we would sort of

stifle innovation for anything further down the road.

So yes, we could short-circuit this process; but

again, the subcommittee and CASAC members signed off

on that letter saying, no, do it the right way. That

right way requires that field testing, that even
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though the technology is available, ORD would need to

go through over a few years and work in; and then

that also buys some time for the innovators out there

to bring their products in.

DR. SAMET: So Kathleen and then Ted.

DR. WEATHERS: So is it possible from a policy

perspective to say that while direct measurements of

light is the goal, we're proposing to do a bridging

approach and as those methods become available, will

be compared against this bridging approach? Is that

acceptable to point to the need for a direct

measurement, but make the recommendation that a

bridge modelling approach be used?

DR. MARTIN: We could certainly as part of

setting a standard defined in terms of calculated

light extinction indicate that is the Agency's goal,

to work to develop something; but we can't commit the

Agency in the future to actually accomplish that, and

the standard would be what the standard was. And if

there was not funding to do the work we all agree is

appropriate to do, the standard would remain what the

standard was until and unless we changed it. So we

can all say it's a goal to do a bridging approach,

but whatever standard we put in place will be the

standard until we change it.
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DR. WEATHERS: I guess what I was asking was,

if you do that, if you say the bridging approach --

this is the approach, this is the indicator, but also

saying that in the future -- this may be just a

message. It's not a -- you know, it's not a policy

agreement. In the future direct measurements would

be ideal.

DR. SAMET: Yeah. What Karen is actually

saying is that a bridging approach becomes the

approach until it's replaced by something else when

the science supports it. And in fact, if for

whatever reason the money needed to develop the

methods for measuring light extinction to the

standard required were not developed, then things

might remain --

DR. WEATHERS: Right.

DR. SAMET: I think she's saying we can make a

recommendation that, yes, light extinction should be

the target, that in the -- apparently, in the view of

this committee that there's still design issues to be

dealt with and in preparing a method that might be

suitable for development of a federal reference

method, not there, but that work should be done,

money should be invested and so on, and if that

doesn't happen, then it doesn't happen. But I don't
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think -- Karen's not signing a note here.

Ted?

DR. RUSSELL: And I think what Karen just said

and what the committee has discussed, I'd probably

become a non-bridger. And then when I look back at

the AAMM, I mean, we didn't -- we looked at it and

said in the meanwhile this would be an appropriate

approach with very much the view that that wouldn't

become the rule, that that would be something that's

viable to be used meanwhile, while you do this other

work with the thought that the other work was pretty

much going to get done and you would have an FRM set

of instrument or set of instruments.

So looking at that, if you're sort of giving

us the choice that it becomes, do the instrument, you

know, come up with an FRM versus saying that, okay,

we can use this bridging approach, but it may not --

but that bridging approach becomes law, I think I

quickly become one who just says, let's just go

directly to the instrumentation and you do what you

need to do to get the instruments out there in

whatever time that takes because I don't want to see

us -- see the bridging approach, which we had

recommended with the idea that the instruments would

be there. It would go through the appropriate steps
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to essentially develop the performance-based

standards to have an FRM set of instruments.

So, but what you're telling us now is that you

really can't have a bridging approach and a

promissory note down the way, which is the AAMM.

It's saying, okay, this is our endpoint, but we

recognize maybe you want to do something in three

years -- for the first three years.

DR. MARTIN: We can set a standard using an

intermediate approach on the premise that we

anticipate the work will be done to provide for the

next review moving to a direct-measurement approach,

but we can't promise that's going to happen. How

could we? And until you change it, the standard is

the standard. It's -- you can't be half pregnant

with the standard. You either have one or you don't

because the standard, of course, triggers a massive

amount of effort on the part of the states to

implement that standard; and we either mean it or we

don't.

DR. SAMET: Congratulations on the pregnancy

analogy.

Phil?

DR. MARTIN: You pushed me into it.

DR. HOPKE: We could do -- at least for
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extinction, it's fairly easy to do a standard sodium

sulfate spherical aerosol. Okay. We can generate

that. They're good-size chambers. We could line up

the nephelometers and set a standard for what their

response needs to be.

DR. MALM: It's already been done.

DR. HOPKE: What?

DR. MALM: That's already been done.

DR. HOPKE: I understand. But it hasn't been

done by EPA, so it's not approved; okay?

But the point is that that's technologically

feasible and that would get us off the ground pretty

quick with respect to extinction, with regards to

defining the FRM as anybody who could make that

measurement within some reasonably defined error

bounds.

Extinction becomes a little bit trickier

because the question is extinction on the fly or

extinction on a filter, and those are not quite the

same things. But again, we could still define one or

the other as the standard for the time being.

There are instruments that do absorption on

the fly. There are instruments that do absorption on

a filter. We can certainly measure the absorption

on -- we can make filters with known absorption,
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which we can measure independently integrating

spheres or things like that. So there's some

absolute ways we could calibrate what that filter

absorption is and, again, compare the instruments.

Bill looks quizzical, so have I said something

untoward here?

DR. MALM: That's fine.

DR. HOPKE: Okay. So I think that within a

fairly reasonable amount of time one could

fundamentally calibrate or check nephelometers,

fundamentally check light absorbing systems on

filters, and that's a lot easier than doing it on the

fly. So let's define our absorption as absorption

collected on a filter and move on.

DR. SAMET: But isn't Karen's problem that in

three or four months this PA needs to be done and it

has to have a clear -- lead to a clear

recommendation? I mean, there's no time -- this is

all work that comes -- that supports the next

go-around. So I mean, I agree there's work to be

done, but that doesn't solve our dilemma for the next

hour or 45 minutes.

Tom?

MR. MOORE: I'll try and be quick, John.

I think what Phil just said, if I could boil
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it down, is that this is not a scientific issue with

respect to the instrumentation. It's just a

technical process issue and so -- but that may stop

it from moving forward. I mean, EPA struggled for

the last 20 years about design specification versus

performance and we pendulum back and forth. So maybe

this goes to Vanessa's idea about what should be the

research approach going forward. You know, what are

the specific recommendations about tying together

implementation of these standards with the research

agenda, which I feel is kind of separate right now.

So as I was trying to say, I'm an optical

advocate; but I'm not a non-bridger. So there are

tremendous advantages to doing the bridging approach.

You know, the health folks will get a lot more data

than they have now. So I mean, I'd be willing to

facilitate some kind of a solution that includes

starting with the bridging, but there has to be a

clearly defined objective to get to the real variable

we're trying to measure.

DR. SAMET: So one issue -- and I don't know,

maybe, Karen, you can respond to this -- as I heard

the bridging options, if one were to use PM2.5 alone,

that is the simplest bridging option I would -- you

know, for obvious reasons. The question of
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developing this speciation approach, while it might

have benefits in expanding our, sort of, knowledge of

variation of PM species across the country, would

involve -- I mean, I don't know what's involved there

in terms of creating new, quote, reference method and

how much effort putting that bridge in place is. If

the work to get to a direct light extinction measure

could be done relatively quickly, you know, how fancy

a bridge is needed. And I think we heard Rich saying

that maybe PM2.5 is not so bad.

DR. MALM: Well, I agree basically with what

Phil has said, but there's no way -- I don't think,

Phil, you're going to get all that. I mean, it takes

time to generate aerosols and set these studies up

and all that kind of thing. So I don't think all

that can get done in the time frame that they need to

get it done in here if they're going to get it -- you

know, come up with a proposal for a standard within

the time frame of this go-around.

So I don't think that there's -- I don't think

there's any alternative other than -- if we're going

to get it done now -- any other alternative than to

accept a bridge with the idea that they've made some

commitment to move toward an optical measurement down

the road. But if you're going to get it done this
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go-around, I think the bridge is it; and all we need

from them is a timeline and some sort of -- you know,

if Congress cuts their budget and they can't afford

it, they can't afford it; but it's better to get

something out there now with a bridge than to do

nothing at all.

DR. SAMET: Joe, did you have a comment? Oh,

that Joe. The other Joe, okay.

DR. HELBLE: I was just going to ask for

clarification because what I'm understanding what

Karen is saying is that, while we may all be in

agreement that a bridge should be a bridge and here's

the goal that we're moving towards, in the end a

bridge is not a bridge. It's simply a promise that

we'll think about it and we'll try, that when we set

a standard, the standard's set and moving to

something new depends upon budget, it depends upon

research, it depends upon the next review, it depends

upon changing the standard.

So what I'm hearing you say is that we can

call it a bridge; but we should recognize that if we

make the choice to go down this path, we're really

setting a standard. And we all have to, I think in

varying degrees, individually assess what the

probability is if we move towards an optical
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measurement and in terms of a time frame; and my

sense is that probability is not very high.

DR. SAMET: Okay. Chris?

DR. FREY: Yeah. I guess I'll sort of clarify

the flip side of that is my understanding from the

discussion, is that with regard to using optical

instrumentation, given the, I guess, the bureaucratic

hurdles, for lack of a better term, to establish that

as an FRM, that there's not a way in this five-year

cycle to see a standard develop. That's sort of

delayed until such time that the FRM is successful

and that process is completed. So that, really, I

just want to clarify, that our option or the Agency's

option, really, is either, A, create a standard based

on the so-called bridging approach or, B, do nothing.

And then the other aspect of that is that five

years hence, it seems pretty clear that CASAC would

like to see that the optical methods have been

established as an FRM such that then it's ready for

prime time; but there isn't going to be an interim

possibility that, say, two or three years from now

the Agency could establish an optical-based standard.

That's my understanding from the discussion. I just

want to clarify that.

DR. SAMET: Karen --
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DR. SPEIZER: I just want to throw a question

out. What would be wrong with a bridge for five

years?

DR. SAMET: Well, that, Frank, that might

happen; but it might not. I mean, I think that

really depends on, sort of, what happens in the next

review. Karen, is that correct?

DR. MARTIN: Yes.

DR. SAMET: And I think Chris did say it

right, didn't he?

DR. MARTIN: Yes.

DR. SAMET: Mort?

DR. MALM: Whether you monitor visibility

directly, extinction directly, you're doing it by

reconstructing the extinction. I would bet you that

the same endpoint -- that the endpoint is going to be

the same no matter how you do it. If our goal is to

improve visibility, this interim technique, this

reconstructed extinction will accomplish that just as

well as a direct measurement. I agree that direct

measurement is better and all that sort of stuff and

certainly would be my first choice. But if our

endpoint is to improve visibility, reconstructed

extinction will get the job done.

DR. SAMET: Okay. Mort?
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DR. LIPPMAN: Well, the question then is do we

need to reconstruct it or would a humidity corrected

PM2.5 serve that purpose as well. The simpler one

that Rich has proposed may be adequate also.

DR. SAMET: Okay.

DR. HOPKE: Again, we have the problem of

speciation data is only going to be collected every

third day for 24 hours, and what we're clearly

interested in is short-term high levels of visibility

degradation. So I think, you know, we really need to

be looking at the mass -- continuous mass

measurements rather than something with respect to

speciation at this point.

DR. MALM: Well, the proposals use continuous

mass and weight it some way such that you end up

being closer to reconstructed extinction and you

don't need an instantaneous readout. The states are

going to make decisions. They're going to create

plans to meet the standard over long periods of time.

It's nice to have instantaneous data and to be able

to understand it, you know, as it's being measured;

but you don't need it. You don't need that kind of a

measurement if your goal is to create some sort -- is

to create a plan that allows you to reduce certain --

you know, to improve visibility. You don't need that
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instantaneous feedback, although I agree it's awful

nice to have.

DR. SAMET: So let me just read a sentence

from a CASAC letter April 29th, 2010, signed by Ted

and myself. So just to remind us that here it's

talking about the different -- sort of, the preamble

is talking about these different light extinction

methods promising alternatives. As these devices are

not currently commercially available, costs are less

certain and they would have to be thoroughly tested

for use in a network. This is promising future

things. Data from existing continuous PM2.5 federal

equipment method monitors could be used as a

surrogate for fine-mode visibility assessment until

data from extinction monitoring methods are more

widely available. Subcommittee members use such

mass-based methods as a practical interim approach or

bridge to extinction monitoring.

So this seems quite clear and consistent with

the discussion here, and I think I've heard, possibly

with the exception of Ted, who I think was responding

in part to, sort of, the possibility that light

extinction methods would not necessarily be

implemented, that we should not have a bridging

option, but otherwise that the, quote, "bridging
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approach" was reasonable, understanding that what

we're calling a bridge might turn into a dead-end, is

that --

DR. RUSSELL: Correct.

DR. SAMET: Okay.

DR. RUSSELL: I mean, I would point out the

sentence right before the one you said is that we

only do have -- the filter-based approaches are

there, and they just have to go through -- well, the

performance-based standard would have to be developed

and that we recognize that would take time. And it

was the committee's view that, in the meantime while

you do that, the bridging approaches would be viable.

I don't think it was ever the committee's thought to

short-circuit it and the bridging approach would

become the standard. If we had recognized that, I

think we would have been pushing much more saying --

DR. SAMET: So we can certainly state that

very strongly in our letter.

Yeah, Lowell.

DR. ASHBAUGH: My understanding right now is

that we could recommend that you go directly to a

light extinction standard, but you're not going to be

able to implement it right away. So if that's the

case, we're left with two choices. One is a PM2.5
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mass standard and the other is this hybrid approach

of calculation. Either one of those, if we recommend

one of them, may end up being there forever if you

can't get to a light extinction standard or it may be

there for a much longer than we anticipate. If

that's the case, I would just as soon go with the

calculation method that was proposed and trust that

the EPA will progress toward a light extinction

standard for the next round. But in the meantime,

understanding that whatever method we choose now may

end up being there for a longer time than we expect

if things don't go the right way.

DR. SAMET: Tom?

MR. MOORE: So I read, as you all can tell, I

read this section pretty carefully that's in the

current draft, and it really doesn't tease out any of

the detail that we spent the last hour talking about.

So I would hope that the final version, pending

everybody's comments, would go through this and kind

of tease out the detail because I in fact think that

EPA ought to recommend to its Administrator that, you

know, we ought to measure optically; but we can't do

it right now. Because I think that's what CASAC is

saying, here's the preferred approach; but we all

understand we can't do it right now. And you know,
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the conclusions in the AAMMS report are not really

carried forward into this section, at least the part

that I'm looking at here on 4-32.

DR. ASHBAUGH: Tom, you're talking about

putting explicitly in this PA the idea that we want

to move toward the light extinction?

MR. MOORE: Correct, right.

DR. ASHBAUGH: Yeah, I agree with that. Yeah.

MR. MOORE: And so if that were possible to

do, I think it's a little bit different take on what

EPA is recommending in its Policy Assessment for the

Administrator to consider as opposed to what we're

trying to do, which is craft an interim approach.

But if we don't get that kind of recommendation from

EPA to its management, then it's a self-fulfilling

prophecy. We're not going to get this technology far

enough advanced to be looked at.

DR. SAMET: So this I think has to do with the

strength with which we make our recommendations.

Ted, you're going to be the author of this

piece of Voltairean prose. Don't let the perfect be

whatever. So I think we've circled this issue. I

mean, I think we've had enough discussion of it. I

think now, just maybe take a crack in the remaining

minute or two before break with what you're going to
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say.

DR. RUSSELL: Thank you. So how I would

phrase what we have said is that, first, CASAC

discussed the various alternatives presented and

recognized that there are strengths and weaknesses of

each one and members were divided on their choice --

on the potential bridging approaches and using a

bridging approach at all.

The committee as a whole very strongly prefers

direct measurement of visibility extinction, but

recognizes that it would take some amount of time to

develop FRM instruments that could be deployed in a

network. Given that --

DR. LIPPMAN: Were they developed or selected?

DR. RUSSELL: The AAMM was very specific that

we want to have performance-based standards, so I

think it's develop standards, performance-based

standards for the instruments. So it wouldn't be

select. It would be to develop -- develop the

standard for the FRM.

DR. LIPPMAN: Not develop the instrument,

develop the FRM.

DR. RUSSELL: Right. Develop the standards of

the FRM.

DR. STALLWORTH: You're saying given that --
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DR. RUSSELL: Given that. Thank you, Holly.

The committee was divided on directly

recommending that we set -- that we go directly to

direct measurement or to adopt the bridging technique

recognizing it could become a bridging technique for

this review.

So how would you augment that remark?

DR. SAMET: So I think after -- the issues

that we are going to have to come back and face up to

after break is in terms of what is anticipated to be,

let's say, the interim before there's a direct light

extinction measure, whether that is PM2.5, humidity

corrected, maybe regionally finagled, as Rich has

proposed, or it's this speciated approach that is in

the document. So I think we ought to come back and

have that discussion. Take the 15-minute break,

check out unless we think we need another day and

then get back at 10:15. Okay. Thank you.

(Recess taken 9:59 a.m. - 10:16 a.m.)

DR. SAMET: So let's see, I think we're back

with, in a sense, maybe Ted and Bill because I'm not

sure we settled on the, quote, "interim" or

"bridging" indicator. So I think we should just go

back and have a little bit more of that discussion

and see if we have a preference, I think, among --
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between the two options.

So, Ted?

DR. RUSSELL: So between the two options,

again, one is just using PM2.5 mass directly and then

there's the reconstructed visibility. And EPA states

pretty clearly that their preference is the

reconstructed visibility using speciation data. And

that's -- I agree, is that of the two, that data

exists and we might as well do that -- do that

calculation even given the uncertainties. And I

think my issue would be is that there's just more

uncertainties involved than are actually recognized

there. I think either way, actually, I will say that

I don't think we want a standard that's based on

micrograms per meter cubed. I think we do want it in

terms of light extinction. So, and maybe that comes

to the next comment or next question. So those are

the two.

And from what I take from the discussion by

the committee, I think there's more support for the

calculated light extinction using the speciation data

as a bridging approach, though there is some comment

that just using city-specific correction and using

purely the PM2.5 mass measurement has some support

because it's easier and, again, there's -- it's not a
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huge uncertainty or a huge likely bias.

So the way I currently interpret the committee

is that there's more support for the -- rather that

they have specified, though my comment would be that

they probably should add PM coarse if they can just

because the reason why we went with PM2.5 was because

we looked at it as bridging towards an instrument

that would only do PM2.5. So that's my take on it.

So I think there's more support for the more involved

calculation.

DR. SAMET: Okay. Rich, do you want to

comment?

MR. POIROT: Well, just to be clear, the

so-called more involved calculation, the so-called

simple approach, ten-step simple approach outlined in

the document, as I understand it, would use the

continuous fine mass measurement data along with

continuous RH measurements. And then for the month

in which those data were collected, it would go

consult the speciation data to come up with an

average monthly speciation, which it would then

disaggregate to an hourly basis and combine with the

mass and the RH.

So what I was proposing as an alternative was

to use historical monthly or seasonal. I think
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monthly may be even gilding the lilly more than is

necessary. I don't know. It can certainly be tested

such that you could have your site specific -- or if

it were possible to do on a regional basis --

speciation information in advance rather than three

or six months, or whatever it takes to get the

speciation data back after the fact. This is an

instantaneous effect. And to have to wait three

months to know what it was seems both silly, number

one, I think in terms of all the uncertainties; not

adding very much uncertainty to use the historical

rather than the concurrent month's data, number two.

And then three, it's missing an opportunity to

utilize this information in near realtime as a

supplement to other things that are measured and

reported out to the public in that way.

So that's what I was talking about as a

simpler approach. It's really the same approach.

It's just a question of can you do just as well or

very close to just as well using historical data

rather than the concurrent month. So just to be

clear about that, that's what I was proposing and I

still think that that would be just as good and worth

evaluating. It's something that can be evaluated;

and if the Agency would have the time to look at it,
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I think it would be useful.

DR. SAMET: Mort?

DR. LIPPMAN: I disagree with everything that

Rich just said.

DR. SAMET: So there might be several views

captured on this point but perhaps a sentiment that

the speciated is possibly more accurate. Although, I

mean, as you point out, Rich, the R

2

with the PM mass

alone was high and improving on it a bit might not

make that much difference in practice, I suppose.

Tom?

MR. MOORE: So I agree with Rich and, of

course, in practice that's exactly what PM2.5

nephelometry does, to back-calculate PM2.5 right now

is it uses historic, monthly. So this is something

that I think is a standard practice already.

The problem with the correlation just staying

with PM2.5 mass is that the composition is variable

between every site, so it's an artifact of that. So

I think that's why we want to do the speciation, not

just limit it to PM2.5 mass.

MR. POIROT: You know, could I just mention

also there are a couple different efforts that do

this in reverse. EPA used to fund Sonoma Technology

to take the airport ASOS visibility data and tap into
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it at its raw level before it gets binned and

truncated and most of the useful information content

gets thrown away and to report that out in near

realtime for the AIRNow system. And then they also

had a generic inverse F of RH drying function that

they applied to that data, and it was used and it was

very useful to states to compare to their fine mass

data.

In fact, I personally use the airport ASOS

data applying an inverse F of RH to just dry it out,

understanding that, you know, most of the time you've

got some sulfate and nitrate mixed in with your

organic. Most of these are always mixed together,

and a generic function actually works really well.

But I use it to evaluate whether I think my fine mass

monitor is working right. I trust the visibility

data better than I do my FDMS TEOM that is all over

the place.

So again, I think that there's a lot of

practice with doing this kind of thing and I really,

you know, I think we're talking -- we keep talking

about all these uncertainties, I think probably

because we know so much about this subject area, not

because we know so little about it.

DR. SAMET: I think, why don't we go on to
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Charge Question 13. Well, so this is on the levels

and forms, so the secondary standard.

So, Lowell, do you want to weigh on this one?

I don't know if we've lost -- I guess we lost Bill?

DR. STALLWORTH: Yeah.

COMMENTS ON CHARGE QUESTION NO. 13:

DR. ASHBAUGH: I didn't have a lot to say

about it. I thought the logic behind it was done

well. The document was clearly written on it. I

didn't really have a lot to comment on for it. I

know Bill had something he wanted to say about it,

though.

DR. WEATHERS: I also didn't have much to add

to this. Bill did mention that it was a little

difficult to follow all the different forms and

levels and permutations, and it would be helpful to

make that clear, that pathway a little bit clearer.

And it seems to me this is intimately connected again

to the indices. So much of this reflection is

connected to whatever is chosen for the indicator.

On question B, it seems to me the hour daily

maximum form can better capture events, short-term

events; but I don't have strong feelings about that

either, and so I thought it was fairly clearly laid

out.
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DR. SAMET: In light of our discussion, which

might at least lead to the preference for the

speciated indicator, specifically in terms of the

form and level, is what is there -- do you consider

it to be on target, sufficient?

DR. WEATHER: Yes.

DR. ASHBAUGH: Yeah. Yeah, I do.

DR. SAMET: Okay. Others want to weigh in on

this? Tom?

MR. MOORE: So I didn't really feel like the

document made a strong argument for a particular

level in a range that was a factor of three. My

sense of things is that the level might should be at

the upper end of that range as a good rather than

best starting point. I don't have a particular

number in mind, but you know, closer to 191 than 112.

And on the form, I think because the

visibility impacts are likely to be organized

somewhat differently in different parts of the

country, that looking at the entire distribution

across three years for all hours would be the way to

do it rather than trying to bracket it into

individual years or months or seasons or whatever.

So I think that allows places -- again, being a

parochial westerner, that where you have wintertime
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inversions that are quite strong, and those may cross

over the end of the year, I think that's a good way

to do that. So I guess those are my comments on form

and level.

MR. POIROT: I guess I would agree with Tom

that I think for various reasons maybe starting

towards the upper end of the levels being considered

would be prudent given the uncertainties in the

approach, especially with the interim process, and

there'll still be plenty of action, even at the upper

end of the range. And so I guess I would just

recommend that absent any other clear basis for

making a better decision, start somewhat cautiously

and hope to refine things in the future.

Regarding the details of the form, I guess I'd

been one who had been arguing that it seemed to me

that using all the hours at a higher percentile would

be preferable, but it wasn't a big preference and the

information presented this time around that compares

these and some of the appendices has convinced me

that it actually doesn't matter much. It's yet

another one of those things that it actually doesn't

matter that much. So I'm perfectly happy with either

of the worst hour of the day or the lower percentile

or the considering all hours. I just don't think it
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matters.

In fact, the speciation -- that's what we were

concerned about. Are we really going to be going

after different sources by picking those two

different metrics? At least, the illustrations

provided in the appendices convinced me that, no,

we're not. We're going to be going after the same

mix of species and the same mix of sources, so I have

no opinion on that.

MR. MOORE: John, can I just make a real quick

follow-up to Rich?

So the two operational visibility indexes used

the worst hour of the daylight hours to characterize

it right now. So by staying with that model, you

guys would be linking this proposal to existing

programs?

DR. PITCHFORD: We had two alternatives. Each

used only daylight hours. One was all hours and

looked at the distribution of those and pick the top

whatever percent, and the other was just the maximum

daily. So each day only could contribute one hour.

It couldn't contribute multiple hours.

MR. MOORE: The latter approach is what those

two use, I think. The one, the highest hour of the

daylight?
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DR. PITCHFORD: Right. What about it?

MR. MOORE: That's what they use now.

DR. MARTIN: He's saying it relates to the

current.

DR. PITCHFORD. Oh, oh, I see what you're

saying. I see, okay. I'm with you. I didn't

realize.

DR. SAMET: Okay. Other -- Joe?

DR. HELBLE: I just wanted to comment briefly,

offer my support for the comments that Tom and Rich

just made about starting cautiously with the level at

the 191 level for a different reason. Figure 4-2

which reproduces data that were in the Science

Assessment has a fairly large spread in values and

it's based on only four studies, each of which -- or

three out of the four of which had fair amount of

scatter in the data.

With only four studies, I think one can argue

we really don't know what the broad overall spread of

the preference distributions is nationally. The 191

could be an outlier on the high side. It could also

be preference studies that tolerate at the 50 percent

level a much higher level of particulate

concentrations. So as a first secondary standard,

starting at 191 seems appropriate and prudent.
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DR. SAMET: Phil?

DR. HOPKE: I would argue that that's not the

way to go because then we're at 30 micrograms per

cubic meter. And if they set the primary standard at

30 micrograms per cubic meter, there's no need for a

secondary standard and we've lost the opportunity to

get our foot in the door.

DR. MARTIN: But of course, we're talking 24

hours versus one hour between primary and secondary

standards.

MR. POIROT: And extinction versus mass.

MR. MOORE: And just closer to 191, not 191,

so.

DR. HOPKE: I still think it's risky, and the

point is I think it's important to set some stretch

goals. So I would be much happier looking at

something more of the 20 or 25 rather than....

MR. POIROT: This brings up kind of a related

topic, but I don't know how it fits the charge

questions. But with an extinction indicator, no

matter how you combine the other things, you're going

to have a general pattern where there's a -- some

level is more frequently exceeded and by larger

amounts in humid eastern urban areas and, depending

on the level, less frequently or not exceeded at all
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in drier western urban areas. That's inevitable.

That's the nature of the beast and how it's going to

go, and that's why I think we've been arguing in past

meetings of the importance of the implementation

phase or the concept of a progress-based rather than

threshold-based approach. It's going to be

critically important given that that's the nature of

the beast. And Karen has informed us very clearly in

the past that the Agency can't do that; and we

understand that if you can't do it, you can't do it.

Nevertheless, from a science perspective that kind of

an approach would be very desirable for this kind of

a secondary standard.

DR. MARTIN: Just a point of clarification, my

comment before was that you couldn't build a

progress -- a progressive definition of a standard.

You can't build the progress-based approach into

defining the standard. But how one lays out

implementation strategies to meet a secondary

standard where the app doesn't specify specific time

frames, that's a much more open question.

MR. MOORE: So is there room for us to

recommend that you consider that in the context of

the Policy Assessment as a way for the next panel to

address the issue that Rich is bringing up?
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DR. MARTIN: It's broader than the scope of

the Policy Assessment for a standard. But if it's a

view on implementation that the committee wishes to

provide advice on, it's perfectly reasonable to do

so.

DR. SAMET: Okay. Other comments on Charge

Question 13?

(No response.)

DR. SAMET: So that brings us to 14, Joe,

where certainly we need to make some strong

recommendations for future, I guess, applied

research, in a sense.

COMMENTS ON CHARGE QUESTION NO. 14:

DR. HELBLE: Sure. The comments I'll make

here I think came out largely and equally strongly in

the context of our discussion yesterday regarding

research needs for fine PM and PM10, 2.5. There's a

fair overlap.

So just briefly, as reflected in my written

comments, I thought the major areas of research and

data collection needed to address the uncertainties

related to a visibility-based secondary standard were

captured very nicely in section 4.5 of the PA. As we

said in the past, it's a laundry list; but the list

appropriately identifies the major areas of need,
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both in the area of visibility preference and related

to methods of measurement.

In the area of visibility preference, I think

all of the discussion noted by EPA, both here and in

the earlier science assessment, indicate there is a

strong need for additional urban visibility

preference studies conducted using consistent

methodology. So I'd simply like to support that

recommendation and emphasize its importance given the

broad range of 50 percent acceptability values that

were discussed as possible standards based on just

the four different studies that exist.

In the second category related to methods of

measurement, I think there's been a fair amount of

discussion this morning alone on the importance of

moving forward with developing both methods and

standards to directly measure light extinction.

I support the proposal to conduct studies in

several cities where there's a pairing of direct

monitoring of extinction with enhanced monitoring of

size and composition distributions, continuous PM

speciation monitoring where that can be developed,

and additional work to understand the contribution of

PM10-2.5 in southwestern areas other than Phoenix,

which came out in this suggestion -- in this section,
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I would strongly recommend.

But as an overall comment, I would say that

underlying this overall discussion is a clear need

for better particle size composition distribution

information, meaning particle composition

distributions as a function of particle size. It's

addressed in the discussions of future research needs

in sections 2.5 and 3.5. It's addressed here in the

discussion of the importance of developing continuous

monitoring methods for specific PM components, and

it's also touched on briefly in Chapter 5. It talks

about climate and the uncertainties associated with

the role of aerosols in climate forcing and the

importance of understanding the distribution between

scattering and absorbing aerosols, which means,

again, understanding composition is a function of

size. So in terms of offering suggestions for

prioritization, I would suggest that given the

frequency with which that appears throughout the

document, that's certainly something that should be

near the top of the list.

DR. SAMET: Okay. Let's see, we have Ted on

this.

DR. RUSSELL: The one thing I might add to

what Joe said was, I think actually, as part of the
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urban visibility standard, they should look at the

implications of the entire urban visibility standards

on regional climate forcing. I think we do have to

consider how decreased light scattering in that case

might actually increase regional warming.

DR. SAMET: Okay. Phil, you're one of the

names here.

DR. HOPKE: Okay. Yeah. I mean, again, the

key here will be to develop moving forward. It's

time we develop then the basis for extinction FRM's.

So you know, a key research need is obviously we've

just been discussing how we're not ready to

promulgate an FRM on visibility. We haven't seen any

activity in the last six years on that. It would be

nice to see some real activity on that in the next

five years; so the next time we sit down to do this,

we could roll out an extinction-based FRM with things

already on the shelf that we could pull off in terms

of how we would define the performance of acceptable

FRM's and methods for equivalency.

DR. SAMET: Tom?

MR. MOORE: So I agree with everyone else's

comments. I have an operational one. I'd like to,

again, see a kind of a linked-up operational and

research agenda for the next round of the PM NAAQS
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review, and several colleagues have brought up

specific topics that need to be addressed under that.

I think one thing we've also talked about is

we really need to advance our understanding of what

the objective criteria are for monitoring site

selection, existing sites and networks and what

they're trying to accomplish. I mean, this is an

ongoing activity by EPA and the states, so let's

advance that.

And I think we need to prioritize because the

PM world is pretty broad and pretty important,

impacts both health and welfare and it's very

resource intensive. So I think a logical outcome of

that, that I'd like to identify as a research need,

broadly defined, is what kind of support does it

actually take to characterize PM most fully? What

are the financial or the technical constraints? What

are the administrative support that's needed? You

have to process and analyze those data, you have to

have sufficient metadata; and those data need to be

accessible to everyone for these kind of reviews.

And then one really specific point just to

amplify what Joe said is that with a tighter fine

particle standard possibly and, you know, a start at

a welfare visibility standard, we have an
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intersection for short-lived climate forcers and what

they contribute to both of those. So that's a real

possibility to do two or three things at the same

time. We strategize about that in applying the

standards.

Those are my comments.

DR. SAMET: Okay. Do others want to weigh in

here? Yeah, Kathleen.

DR. WEATHERS: I just want to underscore the

two comments about climate and making sure that in

future research needs that there is this interface

with the effect of aerosols on climate. I also think

that that's a very important topic and needs to be

considered.

DR. SAMET: Okay. Rich?

MR. POIROT: I agree with everyone this time

and wanted to also remember a really good suggestion

that Bill had earlier about an idea to try to develop

an index that would sort of cut across these

different preference studies that I think is actually

a really good idea and might work well. That even as

we're conducting more of them and in different areas,

aiming to find some commonality amongst them, I think

is a really good idea, physically sound and makes

sense. So I just wanted to, since Bill's not here,
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reiterate his very good idea.

And then, as long as I'm stealing ideas, I

think Ted maybe had -- or Phil had the idea to, even

as we're implementing this urban visibility pilot

program, to make sure we include a component of

instrument development, not just the testing of

what's currently available.

So those were two additional things I thought

could be emphasized.

DR. SAMET: Lowell?

DR. ASHBAUGH: Yeah. I just want to reiterate

something that Joe Helble said also and I mentioned

earlier that I think it's also important to do some

more development on continuous speciation measurement

so we can get that fine time increment for what's

causing visibility reduction. That will help us so

much in the future.

DR. SAMET: Ed?

PROF. AVOL: So in this area, maybe more so

even than in the fine and coarse, there's obviously a

lot of work as this develops and becomes a standard

and moves forward. So again, I would just reiterate

the need to prioritize, sort of, where we want to go

most quickly because, obviously, there's a lot to do

here.
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DR. SAMET: Okay. Others? Comments?

And so we've done 14. So I mean, maybe just

to recap and then we can decide what we might or

might not do -- might or might not do next.

So I think from the outset we heard that the

document, I think Rich said, took a reasonable

approach. Bill thought that the array of options of

indicators, levels and forms was a bit confusing.

Perhaps with this discussion, you can be more

focussed now in the document and indicating, perhaps,

guiding the readers through what was a little bit of

a maze of choices and, perhaps, beginning with a

not-so-even preference up front for the visibility

versus -- direct measurement of visibility versus

options and, perhaps, put in some of the branching

structure in thinking about the problem that we went

through today.

The indicator question, I think, is hopefully

still fresh enough in everyone's mind that I don't

need to go through the details of that discussion

again. But I think there, the discussion hinged on

the readiness of the still-in-evolution light

extinction methods and the lack of a federal

reference method and the need then to move to what we

called a bridging indicator that in reality is what
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would come into place in the standard until it's

replaced by something, something else, a direct light

extinction measure. And we went through the two

alternatives, I think in part prompted by Rich's

comments, and ended up with the idea that the

speciated approach might lead to the most accurate

characterization of light extinction.

And then I think there was a sense that the

document was okay in its review of the alternative

levels and forms. I think there's a clear agenda for

additional research that was stated and I think

roughly agreed to by everyone and I think clarified

by our discussion.

So let me ask if anybody wants to add

anything, if EPA has anything else for discussion.

Chris?

DR. FREY: Maybe this is a naive question or

one that has been discussed before, but in talking

about the indicator, is there a -- should there be

consideration given to differences in coverage of

existing monitoring network, is that an issue that

from a practical purpose tends to favor one over the

other, or is there adequate coverage to support the

speciated adjustment?

MR. POIROT: Well, I think -- I don't know.
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We have Tim here. I think there's, what, 550

continuous fine mass sites?

MR. HANLEY: So there's actually closer to 700

continuous fine mass, and then there's -- when we

think of the chemical speciation network, which does

not include IMPROVE, there are 200 stations in the

United States. And then, obviously, IMPROVE has

another 160; but just a handful of those are in urban

areas. I think folks are aware the IMPROVE network

and the chemical speciation network, we consider them

essentially equivalent in terms of the data now. So

I think we're in pretty good shape there.

So things are in good shape, clearly. There

are going to be a few cities that if we had a

strategy for targeting cities over a certain

population, we might have to add speciation, maybe,

like, in Austin, Texas, just as an example. I don't

even know that for certain. But all the big cities

and most cities do have chemical speciation now as we

speak.

MR. POIROT: It was one reason that I

suggested considering trying to do it possibly on a

regional basis. It may not work out. Again, it's

something that could be evaluated, but if you did it

on a regional basis you wouldn't be constrained to
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the subset of the speciation sites that have the

continuous sites.

MR. MOORE: So real quickly, you know, Rich is

right; and that might be the most practical thing to

do. I think that the speciation at every site is a

little different and that's what's going to be

reflected in the value that's used to judge

attainment or non-attainment, so it might be

important to do it on a site-specific basis. And

just to clarify, most of the speciation monitors are

running for 24 hours, one in six days. So we'd be

fitting those back to every hour, every day?

MR. HANLEY: That's right. There's about 60

to 70 that run every third day and the balance run

every sixth day.

MR. MOORE: So Chris, I think that's why

Phil's arguing for a -- and Lowell as well -- a

continuous speciation.

DR. SAMET: Okay. I think we are roughly done

here.

Karen, do you have --

DR. MARTIN: Yes.

DR. SAMET: Karen, don't undo us, whatever you

do.

DR. MARTIN: I would like to pose or just
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share with you the thinking that we have evolved

among ourselves as we've been listening to the

discussion today and it leads us to a process

schedule kind of question.

So we are appreciative of the reflection

you've made and the input you've given. We are

certainly taking away from this support for the

hybrid, quote, unquote, "simplified approach" that we

put forward in this; but we've also heard suggestions

about ways in which it could be further simplified.

And especially, if a longer range goal is to move to

a direct light extinction measurement approach, the

more simplified an interim approach is, the more

sensible it is as an interim approach. And while

it -- the more simplified versions are generally

consistent with the concept we developed in the

second draft, they are clearly different and in our

view would warrant further evaluation.

So one of the things we're considering is to

go back and work more broadly within the Agency,

talking to our counsel as well and consider whether

or not it would be appropriate in light of the advice

receiving -- we've received today to take somewhat

more time to develop another draft of a visibility

policy chapter that would extend the time for that
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analysis without holding up the progression of all

the other work on the primary standards and allow for

the schedule we had in place to be met from a Primary

Standard perspective and potentially consider

splitting off the decision-making process and

standard-setting process by some months to allow for

adequate consideration of the ideas that have been

put forward here. I'm not saying that's what we will

intend to do, but I'm saying that we think it's

appropriate to give very serious consideration to

that and we need to give it consideration more

broadly than just those of us here at the meeting.

I'm going to ask that you would be supportive of

that. And I would ask then, would you be prepared if

that was the course we felt appropriate to take to

review another version of a policy chapter that

addresses visibility?

DR. SAMET: I think that's a reasonable

request, presumably a telephone review would suffice.

And I can understand that you might be bringing forth

data that in terms of these interim options might

look at, perhaps, a simpler proposal made by Rich

versus something more complicated, and I can

understand that you would want to do that. I don't

think I see any issues. It sounds like you would be
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able to meet your requirement on the Primary

Standard.

DR. MARTIN: Right. There would be no change

to that process at all that we're envisioning at this

point.

MS. WEGMAN: (Microphone not used) And John,

we also -- for other requirements on the secondary as

far as making some kind of decision -- but that might

be a --

MS. VU: I don't see any issues that we could

provide given the Panel's willingness to review the

next version of the -- on the Secondary Standards.

The only question I would have is to Ted and some of

you on whether you want to invite the AAMM

Subcommittee members as part of this group or just,

you know, the experts on this particular panel to

weigh in.

DR. RUSSELL: If we're talking about

essentially the simplified approach versus the

somewhat more involved approach, one, I don't think

that that's an AAMM-type issue. It's not really --

DR. VU: I know, because the AAMM Subcommittee

looks at more instrumentation, performance standards.

DR. RUSSELL: Right.

DR. VU: This is more a conceptual,
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particularly based on discussion we just had today,

so it makes sense that this group would do it.

MR. MOORE: So that's a very nice offer. I

think that moves things along without delaying it as

long as the SOx, NOx secondary standards. I think

that's what you're saying.

So with respect to that, how would that tie

in, John, to the idea of some kind of a workshop to

put together priorities and that kind of thing? I'm

wondering if we want to do that as quickly as

possible while all this research stuff is kind of

fresh in our minds.

DR. SAMET: Yeah. I actually see the workshop

as having a, probably, much broader agenda. Are you

referring to the workshop we discussed yesterday

which was sort of the more step back and reflect

workshop? So I think a little bit different agendas

in my mind.

Vanessa?

DR. VU: And I think what I would like to do

is confer with Dan Costa and everybody else in OAQPS

to talk about -- and I do know I spoke yesterday with

Karen and Lydia that the Agency plans to have a

workshop in March to talk about multi-pollutant

approach in terms of research. So the question is
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how do we best -- CASAC, what to advise the Agency on

the research portfolio and set priorities, et cetera.

So we could conceivably have something in the fall to

have a discussion and then the Agency's output of

that workshop proceedings and they will have to bring

back some proposal, and then we'll have CASAC would

provide some feedback.

So but, I'd like to talk it over to Dan and

OAQPS folks and then propose a time, you know, a

schedule and get feedback from the CASAC. And then

also talk about how we're going to bring other

consultants to the group because we're not talking

about PM alone. We're maybe going to talk about

ozone and NOx, SOx and everything else as well

because, you know, resources is not that open-ended.

We have tight resources within the Agency and how do

we best serve in getting CASAC's advice on how the

Agency should proceed. I think it's very important.

We'll try to as soon as possible, but I need to

confer with ORD folks and OAQPS.

DR. SAMET: Okay. I think probably Holly and

I had conferred about whether we should continue on

and look at the responses, but -- yeah, that was my

question.

So we have two options. One is to spend a
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half hour looking at our responses. I don't think we

ought to do that. I think we should talk a little

bit about the schedule, though, to bring this to

completion and we're probably, I think, close to --

coming close to the end. So I think what we should

do is talk over the schedule we have.

I appreciate everybody's hard work. We have

responses from all the different writing teams

compiled. This will need, I'm sure, some editorial

work and clarifications. But that will lead to --

and preparation of the, you know, draft letter to the

Administrator, the briefer letter, to accompany this

that we've been writing and circulation of that. And

then we will need a phone call.

DR. STALLWORTH: Yes.

DR. SAMET: So let's just think a little bit

about timing. Holly?

DR. STALLWORTH: Well, we have the combined

responses to charge questions. It's 16 pages long.

John, I think you and I would put together a

letter based on these responses and I would clean

this up and send it out to the Panel within a week to

be discussed at a subsequent teleconference, which

will be about three weeks later. Does that sound

okay?
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DR. VU: So Holly, you're talking about having

a public teleconference call. We're already the end

of July, so you're talking about probably -- the

earliest is probably the first week of September or

late August because we need to have 15 days in

advance for notification and all that and giving

everybody -- you know. So I would say probably first

week of September. But of course, you have Labor Day

weekend, but we'll figure out a way to make sure that

you all will have a public conference call to further

discuss the draft report and concur.

DR. SAMET: So I suspect at the end of August,

early July (sic) by the time we have to deal with the

realities of scheduling a meeting. So the conference

call -- we probably won't need a long conference

call, hopefully; but who knows. The visibility group

might get going again.

DR. MARTIN: If I might just offer a comment.

Obviously, given what we've just talked about, our

desire would be to get something as soon as possible.

And if there was any way to schedule a discussion by

the end of August rather than extending into

September, that would be highly desirable from our

perspective.

MS. WEGMAN: The schedule which I showed
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yesterday showed the final Policy Assessment --

DR. VU: Yeah. Lydia and Karen, please don't

worry about it. We know what you need.

The point is when we're going to have the

public draft report from the CASAC panel, it will be

two weeks in advance so you have in hand what the

write-up of this esteemed group have provided you,

capture the advice. So you will have it in two

weeks.

MS. WEGMAN: Thank you.

DR. SAMET: Okay. So we will aim for the end

of August. I think probably most people are sort of

back in action the last week of August if they had

disappeared on vacation.

DR. HOPKE: Except the last week of August is

the International Aerosol Conference, where I assume

some of us --

DR. SPEIZER: Yeah.

DR. HOPKE: -- will be going to Helsinki.

DR. SPEIZER: -- is in South Korea.

DR. SAMET: Yeah. The telephones have arrived

in Helsinki. Think Nokia.

DR. HOPKE: Will we have a free call-in

number?

DR. STALLWORTH: Yeah, we can get you a free
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call-in number.

DR. VU: No problem. We have international

phone calls all the time.

DR. SAMET: Okay. Any other issues to raise?

Tom?

MR. MOORE: So I'm a rookie at this stuff. So

then next February, I believe, there will be a

standard that's proposed. So what's our involvement

at the time the standard is proposed?

DR. SAMET: So we have the option when the

proposal comes out to comment and have done so in the

past on such.

DR. VU: So the Agency doesn't request the

CASAC to comment on the proposed rule. However,

CASAC can provide unsolicited advice with regard to

the proposed rulemaking. Yeah, so we would -- Holly

would send the proposed rule out to everyone for

review and then the Chair would have input from you.

If you all -- should you wish to have a public

conference call to discuss the proposed rule and

provide a written comment to the Administrator, we'll

do that.

CLOSING REMARKS BY DR. SAMET:

DR. SAMET: Okay. Well, I think we've reached

the end of this, sort of, document journey. I think
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I was reminded when Vanessa was talking about the

start of this, it was 2007.

DR. VU: November 2007 you all reviewed the

IRP, the Integrated Review Plan.

DR. SAMET: So it has been a long time. There

have been five face-to-face meetings, innumerable

drafts circulated and telephone conference calls. So

I want to thank you all for your hard work and

diligence. I think actually we've covered some

remarkably interesting and complicated issues as

we've looked at what the Agency has done.

I think it's also worth a comment that this is

the, sort of, first -- as I mentioned yesterday, pass

through this revised process. And again, if you had

the longer range view from the old days when the

criteria documents arrived, I think the last PM

criteria document might have been roughly that thick

(indicating approximately a foot), and this was

before documents arrived on CD's. So they were --

they were weighty, truly weighty documents. And you

know, to go back to readable versus unreadable prose,

they just were remarkably soporific, the criteria

documents. I mean, if you can just imagine hundreds

of pages with each paragraph beginning, you know,

Russel, et al. showed; Suh, et al. showed; Vedal, et
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al. even showed; and they were -- and then this would

go on and on and on for, like, 30 pages. And then it

would be, in summary, this evidence is, or something

like that. And I think you've moved to a much better

and clearer process, I think. And then there's the,

here are the data bases as an addition.

So I think some real advances have been made

in the process and, hopefully, that will continue to

be of benefit, I think, really, to, not only to the

Agency, but really to the public to make clear how

these decisions are being made and what the basis of

evidence is. So I think that's been, I think, a good

mutual working ground and I think one where we should

all take some pride in what looks to me to be an

improvement in a process that had been longstanding.

So I want to thank you for your hard work and

thank the committee for your hard work. Some of us

will continue to see each other as we move on.

There's always another pollutant, apparently. And as

we move on to ozone, others, I think Joe and his team

have finished up with carbon -- with carbon monoxide.

Some of you may be sitting around the table

five years from now when there's yet another review.

Mort, no doubt, will be there offering reminders of

what has transpired since -- yeah, 1971, since the
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start of history.

DR. LIPPMANN: Not quite that bad. I didn't

get started on PM reviews until 1980. It wasn't in

the seventies.

DR. SAMET: Well, roughly, it would be the

same. So again, I'm not sure I plan to be there.

Rogene might be.

DR. VU: Nor Vanessa.

DR. SAMET: Nor Vanessa. So there may be a

sweeping out of the old guard.

Again, so thanks.

Vanessa, any last words here?

CLOSING REMARKS BY DR. VU:

DR. VU: Well, I just want to add and thank

you so much, committee members, panel members for

your extremely hard work; and I do know that the

Agency has expressed their appreciation of giving

valuable advice to strengthen the science and for

policy decisions for the Administrator to make.

Also, I want to express my thanks to Dr. John

Samet for chairing this panel -- chairing the CASAC

and then this panel as well.

I don't know whether Lydia and Karen may

want to say something on behalf of the Agency as

well.
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CLOSING REMARKS BY MS. WEGMAN:

MS. WEGMAN: Yes. I would like to say thank

you again to all of you. This has been an extremely

helpful day-and-a-half discussion, very stimulating

for us, gave us a lot to think about; and that has

been true throughout this review.

You've all really devoted yourselves. You all

have full-time jobs and beyond, and we very much

appreciate the fact that you've taken the time to

engage with us on this review. As you well know,

it's an extremely important review, both for public

health and the environment; and your involvement will

make a big difference.

I cannot tell you how many meetings I'm in

where the question is, what does CASAC say, what was

CASAC's advice, what was CASAC's view on this

question or that question. Your advice is absolutely

essential to the work we do at the Agency, and I very

much want to thank you for all your time.

And John, thank you very much for your chair

of the CASAC and this committee. And Rogene, thank

you for all your work. We're going to miss you on

CASAC. So thank you.

DR. HENDERSON: And I'll miss you.

MS. WEGMAN: So thank you all very, very much.
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Safe travels home.

DR. SAMET: Does Karen want the last word?

CLOSING REMARKS BY DR. MARTIN:

DR. MARTIN: I'll obviously echo the thanks;

but more mundanely, we will be back in touch with you

with regard to a schedule on the follow-up for this

chapter then.

DR. SAMET: Great. Thanks. Let's go home.

(The meeting was adjourned at 11:09 a.m.)

---o0o---
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REPORTER: RWK

DATE: 7/26/2010

T R A N S C R I P T I O N C O R R E C T I O N S

U.S. ENVIRONMENTAL PROTECTION AGENCY

SCIENCE ADVISORY BOARD STAFF OFFICE

CLEAN AIR SCIENTIFIC ADVISORY COMMITTEE (CASAC)

PARTICULATE MATTER REVIEW PANEL PUBLIC MEETING

PAGE LINE READS SHOULD READ

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STATE OF NORTH CAROLINA

COUNTY OF WAKE

CERTIFICATE OF REPORTER

I, ROBIN W. KING, the reporter by whom the

foregoing proceedings were taken, do hereby certify

that the proceedings were taken by me in stenotype

and thereafter reduced to typewriting under my

direction; that I am neither counsel for, related to,

nor employed by any of the parties to the

proceedings; and further, that I am not a relative or

employee of any participants thereto, nor financially

or otherwise interested in the outcome of the action.

This, the 11th day of August, 2010.

____________________________

ROBIN W. KING

Notary Public in and for

County of Wake

State of North Carolina

Notary No. 200518700077

My Commission Expires July 4, 2015

Robin W. King

Bryant Court Reporting Services

(919) 387-5853