United States
Environmental Protection
Agency
Office of the Inspector General
Office of Audit (A-109)
Washington, DC 20460
March 1989
Report of Audit
E1 K2*8-11 -0026-9100227
REVIEW OF PM10
MONITORING PROGRAM
VOLUME 2
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TABLE OF CONTENTS
APPENDIX
PAGE
APPENDICES IN VOLUME II
APPENDIX 3 - ACTING ASSISTANT ADMINISTRATOR'S
COMMENTS TO DRAFT REPORT (WITH
ATTACHMENTS) 1
GENERAL COMMENTS 1
ATTACHMENT A - DETAILED COMMENTS 9
ATTACHMENT B - NOVEMBER 21, 1988 OAQPS
POLICY MEMORANDUM 45
ATTACHMENT C - ISSUE PAPER PREPARED BY
PM10 MEASUREMENT TASK FORCE 53
ATTACHMENT D - DRAFT OAQPS COMMENTS ON
OIG POSITION PAPERS 74
ATTACHMENT E - DECEMBER 23, 1987 OAQPS
MEMORANDUM REGARDING STATUS REPORT FOR
PM10 SAMPLERS 85
APPENDIX 4 - ADDITIONAL OIG COMMENTS TO FEBRUARY 24,
1989 RESPONSE TO DRAFT AUDIT REPORT 1
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY (p* ,
WASHINGTON. D.C. 20460 dilL* ~2-r
6A-L3Z
___ n A ICQO OFFICE OF
ftB fc •» I-"' *»" AND RADIATION
MEMORANDUM
SUBJECTS Response to the Office of Inspector General's Draft
Audit Report E1K2*8-11-0026, Review of PM10 Monitoring
Program ^^^\ j* , /] __
FROMt Don R. Clay, Acting Assiteftfptr Administrator
for Air and Radiation T*NR-443)
TOs Ernest E. Bradley III
Assistant Inspector General for Audit (A-109)
As required under EPA Directive Number 2750, this
memorandum responds to the draft of the Office of Inspector
General (OIG) report, "Review of PM10 Monitoring Program*
(E1K2*8-11-0026).
GENERAL COMMENTS
The audit resulted in three major findings!
(1) EPA needs to ensure that different attainment
decisions are not made solely because of the use of different
types of PM10 monitors;
(2) EPA needs to provide guidance and clarify
authority for using data from nonapproved monitors; and
(3) Additional PM10 monitors are needed and EPA needs
to take a more active role to ensure that monitor requirements
•re met.
With respect to findings number (1) and (2), the Office of
Air Quality Planning and Standards (OAQPS), within the Office of
Air and Radiation (OAR), has already issued • revised policy on
the use of PNio measurement data. A copy of the revised policy
was provided to your staff in November 1988. With respect to
finding number (3), as discussed briefly in the IG Draft Report,
we maintain that all but four PM,0 monitors were needed in
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October 1988 to meet regulatory requirements and our analysis of
the PM10 monitoring needs was, in fact, comprehensive. We agree
that an analysis of the final PM10 monitoring needs should be
conducted on a periodic basis.. Thus, we have satisfied the
concerns expressed in the stated objectives of the audit.
In reviewing these three major findings (Attachment A), we
feel that we have fully addressed each of the issues. We
provided the IG auditors with the November 21 policy memorandum,
•Revision to Policy on the Use of PM10 Measurement Data"
(Attachment B), and the joint Office of Air Quality Planning and
Standards (OAQPS)/Environmental Monitoring and Support Laboratory
(EMSL) issue paper, "The Treatment of Uncertainty in Ambient PM10
Measurements* (Attachment C). The issue paper and a draft
October 12 memorandum (Attachment D) provided the IG auditors
with the basis for the revised November 21 policy memorandum.
Me have several concerns with the factual accuracy of this
report. There are major discrepancies throughout the report
and, in this document, we have responded to what we perceive as
the major discrepancies (see Attachment A). We are particularly
concerned about the draft report's failure to integrate the
information provided by staff from the Offices of Air Quality
Planning and Standards (OAQPS) and Research and Development
(ORD). We believe this failure resulted in a distorted analysis
which we believe led to an unfair characterization of OAR effort a
to address this important issue. This in turn led to erroneous
conclusions (especially in the third major finding) which
resulted in what we believe to be inappropriate recommendations.
In particular, we have concerns with the draft report's
discussion of the third issue. The vast majority of the
discussion of the third issue focuses on a presumed shortfall in
PM*o monitoring of 81 monitors. The IG investigators were
provided with detailed tabular information on October 12, 1988,
which clearly showed that the shortfall as of October was only
four monitors needed to satisfy the 1988 monitoring requirements.
While the IG investigators reference the draft memo of October
12, 1988, from the Chief of the Monitoring and Reports Branch to
the Supervisory Auditor of the OIG, no further contact was made
by the IG investigators after October 12 to clarify any questioni
the IG staff may have had. Over three months passed from the
tisM of that mweting to your msmo of January 25. As a result,
the emphasis of the entire section was on an outdated estimated
shortfall of 81 monitors. We believe that more than ample time
was available to avoid the factual inaccuracies contained in thii
report.
As a final comment, I would lika to point out that we have
spent a considerable amount of time responding to this audit.
This includes not only OAR staff but staff from ORD and the OGC
as well. The time was spent in many meetings with the IG
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auditors, and preparing written responses to their requests. We
are concerned, however, that much of the information provided the
16 was not integrated into the draft report. Consequently, we
have had to spend an excessive amount of time in responding to
this 16 Report. I would hope that we could work together in the
future to find a more efficient forum for information exchange to
accomplish your goals and, a* a result, improve the overall
operation of the air progri
RECOMMENDATIONS
I will now specifically address each of the recommendations
put forth in this report, as discussed in each Finding. A
•ore detailed response to the recommendations is found in
Attachment A, which also includes a review of the factual
inaccuracies contained in the draft report.
FINDIM6 MUXBKR 1.
XG Recommendation •aabsjr 1-1»
"Establish procedures which allow for flexibility in
interpreting measurements near the PM10 standard.*
Such as
(a) "establishing a panel of experts who would deal
with measurements within a specified range on a
case-by-case basis;*
(b) "not requiring any action for monitor measurements
within a certain "gray zone" around the standard;"
and
(c) "adjusting measurements by predetermined
percentages, depending on the type of monitor."
Response)
He feel that the OAQPS policy on the face-value use of
reference measurement data, coupled with the PM10 State
Implementation Plan (SIP) process, provide sufficient
flexibility for interpretation of measurements near the
PM10 standard. We feel that the appropriate role for a
group of experts is to review PM10 SIPs, and not to
review all measurements within a specified range.
Although options (b) and (c) above were discussed in
the OAQPS/EMSL issue paper, they could not be
recommended after weighing and evaluating their various
advantages and disadvantages.
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We have determined that the use of all PM10 data
produced by reference samplers at face value is clearly
the best course of action.
16 Recommendation Hunter 1-2*
"Establish procedures which provide for documenting the
basis for deciding an area's attainment status."
•
Response
There is some subtlety involved with the terminology
"attainment status." The new implementation
regulations for PM10 do not require that an area's
status be formally classified as attainment or
nonattainment. This is because PM10 was not the
indicator pollutant for the particulate matter national
ambient air quality standard (NAAQS) on August 7, 1977,
when the Clean Air Act (CAA) was amended. Therefore,
it is not bound by the provisions of Section 107 and
Part D of the CAA regarding requirements for
nonattainment areas. Instead, PM10 is only covered by
the implementation plan requirements of Section 110,
which specify that an area's SIP is judged to be
adequate or inadequate to demonstrate attainment with
the NAAQS. The process by which the SIP is developed
and approved, therefore, is the appropriate regulator*
documentation for defining an area's status with
respect to attaining the standard. More details on
this issue are contained in our responses to pages 8,
9 and 17 of the Draft IG Report, contained in
Attachment A.
ZG RecoBBendation Boater 1-3 *
"Work with appropriate EPA officials to obtain any
regulatpry changes that are necessary to provide a
clear, authoritative basis for the selected policy."
The November 21 policy memorandum issued by OAQPS to
the Regional Air Directors described and communicated
the proper use of PM10 measurement data. We have
determined, in cooperation with other relevant offices,
that regulatory changes are not essential.
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FINDING NUMBER 2.
IG Recommendation Number 2-1 i
"Not allow data from a nonapproved monitor to be used
to determine exceedances if that data was obtained from
a monitor that was placed in service after August 1,
1988 (the date by which monitors were to be in place
for those areas expected to have the -worst PM10
pollution) "
Response
This is consistent with the November 21 policy
memorandum .
ZG RecoomendAtion number 2-2 t
"Allow data that was acquired in the past or is
acquired in the future, from a nonapproved monitor that
was part of the SLAMS or NAMS Network that was being
used prior to August 1, 1988, to be considered by a
panel of experts as a basis for determining whether
exceedances have occurred . "
Response
SLAMS and NAMS networks were only approved
conditionally if nonreference monitors were currently
being used. These monitors are supposed to be replaced
or upgraded with reference samplers after August 1,
1988. If we were to allow data from nonapproved
monitors to continue to be used, then we remove the
incentive for the monitoring agencies to upgrade or
replace these samplers. According to the November 21
policy, data from nonapproved monitors that were
collected prior to August 1, 1988 can be used, subject
to the rules specified in the memorandum. Data
collected after August 1, 1988 cannot be used, unless
the aonitor is subsequently approved by EPA.
^K"^P •
"Allow measurements from such nonapproved monitors
(monitors that were part of the SLAMS and NAMS network
prior to August 1, 1988) to be treated like data from
approved Monitors, for purposes of making attainment
decisions, when the PM10 measurements are greatly above
or below the PM10 standard (as illustrated by the data
from Medford, Oregon); the cutoff points around the
standard may be decided by the panel of experts.'
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Response
In our November 21 memorandum, .an analogous approach
was, in fact, established. Our approach is to set a
general gray zone within which nonreference PM10 data
would be viewed with uncertainty and outside of which
the data would be used with more authority.
The gray zone limits specified in the November 21
memorandum were recommended by the OAQPS/EMSL committee
of PM10 experts, who prepared the issue paper on PM10
measurement uncertainty.
16 Recommendation Number 2-41
"Allow a panel of experts to be flexible in deciding
whether monitor measurements•near the standard should
be treated as exceedances, depending on the type of
monitor, the amount of differences between the
measurement and the standard, etc.*
Response
The OAR, and ORD believe that a uniform interpretation
of PM,0 data for all monitoring areas is preferable to
one which varies from area to area. With a uniform
approach, the rules are defined in advance. This
permits a consistent, more unbiased interpretation of
available PM10 data. We agree that flexibility is
needed in order to make comparisons with the standards,
but prefer to do so by permitting exceptions to a
general rule, as stated in the November 21, 1988,
policy.
16 Recommendation Vumber 2-5 s
"Work with appropriate EPA officials to obtain the
regulatory changes that are•necessary to implement the
•elected plan of action including, if appropriate, the
modification of 40 CFR Part 50.6(c), which does not
clearly allow the use of any data from a monitor not
approved by MSB in the determination of whether
•xceedances have occurred.*
Response
While 40 CFR 50.6(c) and Appendix K do not clearly
allow the use of nonreference data for corroborative
purposes, they also do not disallow the use of the data
in this manner. If time were not a factor, we would
agree that revising section 50.6(c) to clearly and
expressly permit the Agency to consider nonreference
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data in making attainment decisions might prove the
best course. Amending the regulations would remove any
ambiguity that now exists regarding our reliance on
Appendix K. It would also require EPA to undertake
full notice and comment rulemaking, however. That
process could take years. As the IG report points out,
reference method monitors were required to be in place
by August 1988. There exists the distinct possibility
that the Agency would have 3 years of data from
approved monitors across the country by the time it
finally promulgated a revision to the regulations that
would allow the use of nonreference data when less than
3 years of data from an approved monitor was available.
Thus* the rulemaking could prove pointless.
Given the practical impediments to revising section
50.6(c), we believe that the best course is the one
embodied in the November 21, 1988 Revision to Policy on
the Use of PM10 Measurement Data. It is fair, sensible
and legally defensible. While it provides a general
framework for using nonreference data, it also provides
sufficient flexibility in that OAQPS approved
exceptions are permitted. Moreover, it may be
implemented immediately.
mdation Huaber 2-6»
"Communicate EPA policy to State and local officials
through the Regional Offices.*
Response
This has already been accomplished with the November 21
policy memorandum to the Regional Air Directors.
FXHDXHG NUMBER 3.
16 RecosMBendatxoii
"We recommend that the Acting Administrator for Air and
Radiation ensure that a comprehensive analysis is
completed of PM10 monitor needs, which includes an
assessment of the questions we have raised."
Responset We believe that OAQPS has satisfied this
recommendation with its ongoing reports on the status
of the PMto network, by tracking the Regions' progress
through the Administrator's strategic planning and
management system
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8
As early as 1983, OAQPS conducted a critical review of
the existing TSP and PM10 data in an effort to identify
those areas of the country having high probabilities of
exceeding certain PM10 concentrations. These areas
were then used as the basis for planning PM10
monitoring needs and calculating the resources
necessary to meet these needs. These analyses were
included in the Part 58 monitoring docket. As new data
entered the National Aerometric Data .Bank, the critical
areas were revised, along with the PM10 monitoring
resources. Tracking of these critical areas continued
and, in February 1985, OAQPS issued the first of 13
PM10 monitoring status reports. The 14th PM10 status
report is in the process of being completed. In
addition to the status reports, OAQPS also tracked the
Regions' progress in establishing PM10 samplers in the
critical need areas through the Administrator's SPMS.
Independent of the 16's efforts, OAQPS initiated a PM10
monitoring task force to investigate the PM10
monitoring efforts. The results of these findings will
be used to better identify PM10 monitoring
deficiencies. The OAQPS believes that this effort,
along with its ongoing status report, satisfies the
IG's recommendation.
IG RBcasflMndation Humber 3-2»
•We recommend that the Acting Administrator for Air and
Radiation require that the analysis be updated on a
regular basis in accordance with a specific timetable."
Responsei The OAQPS plans to continue issuing the PM10
status reports at least over the short term, as well as
making a more comprehensive analysis, as needed.
Attachments
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Attachment A
Comments on Draft Audit Report E1K2 * 8-11-0026
Review of PM10 Monitoring Program
RESPONSES RELATED TO
AUDIT ITEM NUMBER 1: "EPA NEEDS TO ENSURE THAT DIFFERENT
ATTAINMENT DECISIONS APE NOT MADE SOLELY
BECAUSE OF THE USE OF DIFFERENT TYPES OF
PM10 MONITORS"
Page 1. Objective is - "to determine whether the Office of Air
Quality Planning and Standards (OAQPS) has implemented
a policy to deal with the fact that one of the two
primary types of EPA-approved monitors gives
consistently higher measurements of PM10 concentrations
than the other."
Response
OAQPS has issued a policy memorandum on November 21,
1988, entitled "Revision to Policy on the Use of PM10
Measurement Data". This is provided as attachment B to
this review. In this November 21 memorandum, Gerald
Emison presents the revised EPA policy regarding.the
treatment of PM10 data produced by reference and
nonreference PM10 samplers. Treatment of data produced
by collocated PM10 samplers is also discussed. This
policy memorandum follows the recommendations of a
joint Office of Air Quality Planning and Standards
(OAQPS)/Environmental Monitoring Systems Laboratory
(EMSL) committee which has evaluated the issue of
potential uncertainty in measurement data produced by
PM10 samplers. This committee's issue paper is
provided as attachment C. For this discussion, the
terms approved or reference sampler shall be used to
represent samplers using a reference method based on
Appendix J to 40 CFR 50 and designated by EPA in
accordance with 40 CFR 53, as well as samplers using an
equivalent method designated by EPA in accordance with
40 CFR 53. Nonreference or nonapproved samplers are
all other PM10 samplers which have not been formally
designated as such.
Page 3. "In regard to the first issue, PM10 experts do not
agree on which of the two approved types of PM10
monitors provides the most accurate measurement of PM10
concentrations. The two primary types of monitors that
have been tested and approved by EPA do not provide the
same measurements under the same conditions. One type
of monitor provides relatively consistent, higher
measurements than the other."
Note: Office of Air and Radiation page references apply to our
draft report. 1
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Response
This paragraph's analysis of the problem is incomplete.
It fails to review the inherent possibility of
differences between sampler types due to the complexity
of particulate matter in the atmosphere and the trade-
off made by EPA between flexibility in design and
measurement uniformity when the performance based
approach was selected for the Federal Reference Method
(FRM). This issue is discussed in the introduction to
EPA's Issue paper and we believe that summarizing it
here would improve the reader's understanding of the
issue. The discussion should recognize that some
discrepancies between samplers should be expected and
was recognized in EPA's response to public comments on
the promulgated FRM approach. The issue is the
magnitude of the discrepancies, not the fact that they
exist.
Thus, the first sentence of the IG's statement over
simplifies the issue. Although current manufacturers
may not agree on which monitor is most, accurate - most
"PM10 experts" recognize that there is no reference for
judging accuracy in such measurements. The see
disagreements center around the rationale for why one Appen
sampler or another may be biased high or low relative Note
to another sampler due to that sampler's vulnerability
to some known or suspected loss or gain mechanism.
Page 3. The IG audit report states that the Office of Air and
Radiation needs to address: "the use of data from the
two primary types of monitors that have been tested and
approved by EPA, in light of the fact that one of these
types gives consistently higher PM10 measurements than
the others."
Page 4. Then, the report continues with: "To deal with this
problems we recommend that a panel of PM10 experts be
established and given the authority to examine all
pertinent factors, particularly the type of monitor in
use, and decide whether particulate PM10 measurements
should cause an area to be treated as being in or out-
of-attainment.... we continue to believe that allowing
experts to evaluate all circumstances when measurements
are near the standard is likely to result in more
defensible action than arbitrarily accepting all
measurements at face value."
Response
The OAQPS approach differs from the latter statement
with regard to two points: (1) the role of a rule
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applicable to all data, and (2) the role of experts in
the data review process. Our approach was to assemble
a group of experts (the PM10 Measurement Working Group)
to consider a broad range of options for the treatment
of PM10 data produced by EPA approved (and unapproved
PM10 samplers), and to recommend a general procedure to
follow for all data usage. Site specific information
regarding measurement differences among reference
method samplers is simply not available to permit a
panel of experts to judge PM10 measurement
acceptability.
The approach which is stated in the November 21 OAQPS
policy memorandum is as follows: "For purposes of
evaluating PM10 air quality status, all data produced
by reference samplers shall be interpreted at face
value and can be used to make comparisons with the
National Ambient Air Quality Standards (NAAQS) for the
purposes of determining attainment or nonattainment, in
accordance with Appendix K to 40 CFR 50". This
approach, however, is described in the context of a
"general policy" in which the following.statement is
also provided: "Deviations to this general policy must
receive concurrence of OAQPS."
We feel that our approach which specifies a general
formula for interpretation of PM10 date is the proper
approach which promotes and encourages national
consistency. We also desire to allow flexibility and
would do so by permitting deviations to the general
approach provided that these deviations receive
concurrence of OAQPS. In practice, these deviations
would be reviewed by a panel of EPA experts. In fact a
panel of EPA experts are involved in the review of
State Implementation Plans (SIPs) and in the review of
air quality data to ensure that existing SIPs do not
require revision. SIPs are also subjected to the See
public review process. Appendix 4,
Page 6. "The standard for particulate matter (PM) was known °ae
total suspended particulates (TSP). As the name
implies, the TSP standard concerned all particulates,
regardless of size."
Response
This statement is not correct. TSP refers to total see
suspended particulate as measured by the original Appendix
particulate matter reference sampler (the hi-volume Note 3
sampler, as described in Appendix B to CFR Part 50). As
such, TSP refers to suspended particles ranging up to
45 microns in diameter.
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Page 8. The last paragraph of the Summary of Findings indicates
an area that requires clarification: "Measurements of
PM10 concentrations from monitors are used to determine
whether an area is out-of-attainment with the national
PM10 standards. A non-attainment area is required to
prepare a State Implementation Plan with controls
stringent enough to bring the area into attainment.
The preparation of SIPs and the implementation of
controls is expensive. It is estimated that industry
will spend $1.9 billion over the next 7 years to
control PM10. "
Response
The role of PM10 data as described above is overstated.
Under the new implementation regulations for PM10, see
areas are not classified attainment or nonattainment Append!
under section 107 of the CAA and sanctions are not ^ote 4
automatically imposed because a SIP cannot provide for
attainment of the PM10 standards. The critical issue
is whether or not the State Implementation Plans are
adequate to attain and maintain the standards. The
review of air quality data with respect to the
standards is just one step in the SIP process and does
not cause any regulatory action to occur by itself. In
particular, the process of developing a State
Implementation Plan starts with a periodic evaluation
of air quality data to determine if violations of the
national ambient air quality standards have occurred.
Once violations occur, all data are considered when
determining which sources to control. Analysis
conducted by air quality dispersion modeling plays an
integral role in this process. Thus, monitoring only
begins a process wherein dispersion modeling and other
analysis provide an independent assessment of the
controls, if any, which might be needed. Most of the
areas now exceeding the PM10 standards are impacted by
area sources such as fugitive dust and residential wood
combustion and not as much by industrial sources. The
1.9 billion is an old estimate which is not longer
applicable. We now believe that this estimate is
likely to be lower.
Page 9. "EPA also needs to anticipate that groups which want an
area to be classified as being in attainment may
challenge the validity of data from the monitor type
that gives consistently higher measurements of PM10
concentration. They are likely to insist that the EPA-
approved monitor type that gives a lower reading is
accurate."
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Response
If a violation of the PM10 standard is observed with
monitoring data, it starts a chain of events. This
does not necessarily lead to increased controls, it
merely starts the SIP Development Process. This
process includes identification of the sources,
evaluation of monitoring and modeling data, evaluation
of control options, etc. In evaluating monitoring and
modeling data we seldom find that monitors are located
at the points of maximum impacts. Thus, modeling data
'is usually used as the major tool for determining this
level of control required. In other words, monitoring
can initiate the process but is seldom, if ever, used
only by itself to develop the SIP, particularly when See
industrial sources are involved. Appendix 4,
Note 5
Page 9. "The 24-hour standard is exceeded if 150 or more
micrograms of particulate matter per cubic meter are
collected on the PM10 filter during any 2 4 -hour
period . "
Response
Appendix K to 40 CFR Part 50 states that a daily value
for PM10 defines a specific 24-hour period to be used
for regulatory purposes and refers to "the 24-hour See
average concentration of PM10 calculated or measured Appendix 4,
from midnight to midnight (local time)." Note 6
Page 9. "Generally, an area is considered to be out-of-
attainment when there are four or more exceedances
within a 3-year period."
Response
The new PM standards are expressed in terms of expected
annual values, thus a monitoring site (and in turn the
area) is considered to fail the 24-hour test for
attainment when the expected number of exceedances per
year is greater than one, or generally, when there are
•ore than three estimated exceedances within a 3-year
period. Thus for a site to be in nonattainment with
the 2 4 -hour standard, it is sufficient but not
necessary for the site to have four or more exceedances
within a 3-year period.
Page 9. "EPA-Approved Monitors Produce Different Measurement s*!0*6 7
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Response
This title is misleading and should be changed. EPA's
performance based approach for specifying PM10 samplers
allows for some level of discrepancy between different
type samplers. The title should be changed to read:
"EPA Needs to Minimize the Potential that |5e ..
Different " With the existing approach for Not "a
approving samplers, there will always be some potential
for uncertainty in PM10 measurements. EPA's goal is
"agreement within 10%." This is a practical and
achievable limit. Relative to the other possible
uncertainties in the air quality SIP evaluation
process, this degree of potential error is not
significant.
Page 9. "Groups may question the validity of data on the
grounds that measurements for PM10 are sometimes
inconsistent with TSP measurement."
RESPONSE
PM10 measurements higher than TSP measurements should
always be questioned. Such results may be indicative
of feperational problems in one or both of the samplers
However, PM10 measurements could be expected to
approach TSP measurements when the samplers are
collecting mostly fine particles (e.g. smoke). Data
should be invalidated if the discrepancy between the
two samplers is large. If the problem occurs
frequently, the network operations should be subjected
to a thorough review.
Page 11. "Moreover, since data from a 3-year period may be used
to make an attainment decision, data being currently
analyzed may include data from 3 years earlier when the
Wedding and the Anderson monitor models were likely to
have recorded wider measurement differences than the
more recent modes."
Response
This section of the IG report does not properly
differentiate between the use of reference and
nonreference PM10 data. The samplers ir. use during the
most recent three years were both the currently
designated Sierra Anderson and Wedding reference method
samplers (eg. SA-321B) as well as their nonapproved
processor samplers (eg. SA-321A). These approved
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models were not available for use prior to 1987. Thus
1985 and 1986 PM10 data were produced by nonreference
samplers. Wider measurement differences are recognized
in these nonreference measurements and are treated
differently than reference data in OAQPS's revised
policy for interpretation of PM10 data. As discussed in
the November 21 policy memorandum, these data are
interpreted using gray zones and not interpreted at
face value like the reference sampler data. The
samplers in use during 1987 which were subsequently
approved by EPA as reference samplers have the same
measurement capabilities as the 1988 models and
therefore do not have been wider measurement
differences than the more current models. Therefore,
the same face value interpretation is appropriate for
both years of reference method data.
This section (pages 9-12) also leaves the reader with
the impression that progress in solving the problems See
with those samplers has not been made. There is
language addressing this in the EPA issue paper (see
pages 2 and 11) that could have been inserted here to
clarify EPA's position relative to the impact and
magnitude of the differences between these two
samplers .
Page 11. "For purposes of this report, it is sufficient to note
that the regulations for approving samplers allow some
uncertainty between approved samplers and that while
differences in measurements between the two monitors
are decreasing, a significant difference still
remains . "
Response
Although the I.G. draft report makes this statement,
the report never defines "significant." EPA's issue
paper has indicated that differences less than 10 See
percent are acceptable. Appendix 4,
Pages 12- Note 10
13. Section subtitled "Potential Development That is Likely
Increase Monitor Measurement Differences."
Response
This section is essentially correct and reflects the
trade-off EPA made when the regulations were proposed
and finally promulgated. The discussion, however, does
not address the primary advantage of allowing
equivalent methods, (e.g., approval of continuous PM10
monitors to address everyday sampling and provide
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diurnal concentration information). EPA believed at
the time of the promulgation that the advantages of
allowing continuous monitors for attainment monitoring
far outweighted the potential for uncertainty in the se(
measurements. Appendix
Note 11
Page 15. "In our opinion, this fact [PM,0 > TSP] may cast doubt
on the validity of data from PM10 monitors, and this
uncertainty may be cited, by those who do not want to
act, as an excuse for not acting on the basis of PM10
data."
Response
See our responses to Page 9 of the Draft Report
regarding this issue. A discussion of this issue is
also contained in the quotation attributed to the
Chief, MSB, on pages 14 and 15 of the IG Drat Report.
We disagree that this is a .significant problem.
Page 15. "We believe some nonattainment and attainment decisions
are likely to be challenged in court because of the
limitations of PM10 technology and inconsistent
readings among the two types of PM10 and TSP monitors.
Response
While many EPA regulatory determinations are challenged
in court, few are reversed. However, challenges wou^^
probably be on the whole State Implementation Plan a^r
not just on the status of air quality measurements.
Both the Wedding and Anderson monitors are approved
reference method samplers, and OAR and OGC believe that
attainment decisions made using either sampler are
defensible. Moreover, EPA's regulations provide for
using reference method data at face value. At the
present tine there is no way to ascertain whether \
either monitor provides more accurate readings. Using
the data from all samplers at face value thus
represents) a reasonable approach to the problems posed
by the divergence in readings from the two samplers and
thereby provide a logical starting point for the SIP
process.
Concentrations recorded by available TSP monitors woul
also be considered in the air quality evaluation
process. Any apparent discrepancies between PM10 and
TSP measurements would have to be addressed in the SIP
8
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APPENDIX 3
Page 17 of 36
Page 16. "We identified two locations, Longmont, Colorado and
Fresno, California, where (1985-1987) data from
Anderson monitors indicated that the areas were barely
out-of-attainment of the 24-hour standard..."
Response
This section of the IG report also confuses the use and
availability of reference and nonreference PM10 data. see
As indicated above, PM10 data was not produced with EPA Appendix 4
approved samplers prior to 1987. For improved clarity Note 12
of the IG report, we suggest that "approved" or
"nonapproved" be used to qualify the appropriate
monitors discussed in the audit report.
Page 17. "Generally when an area is classified (or reclassified)
as being out-of-attainment, the SIP (or SIP revision)
should specify the emission reductions that are
necessary to bring the area into attainment."
Response
"As previously stated, areas are not classified as
being out-of-attainment with the new particulate matter
standards. The use of the incorrect terminology • see
suggests that air quality determinations have an Appendix 4,
immediate regulatory consequence." Note 4
Page 18. "We are concerned whether a company might collocate a
Wedding monitor next to a government's Anderson monitor
and insist that the lower reading be used as the only
legitimate basis for action."
Response \ - ••-" <
Although companies might be expected to use this
tactic, OAQPS's November 21, 1988 Revision to Policy on
the Use of PM10 Measurement Data would provide a
reasonable defense to such a claim. The policy.states
that "when more than on sampler- (or group) is operated
independently by one or more Monitoring agencies
concurrently for attainment assessment purposes, each
Sampler (or group) shall represent a different
monitoring station. The data from each monitoring
station shall be used separately to assess attainment
or nonattainment with the NAAQS.* Thus, any approved
sampler measuring NAAQS exceedances at the site should
be deemed a separate station, and data that
demonstrated a violation of the standard would justify
the Agency's decision to call for a SIP revision. It
is important to note that all data used to judge
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APPENDIX 3
Page 13 of 36
attairunent/nonattainment, including data provided by
industry or environmental groups is supposed to meet
all the requirements for SLAMS specified in 40 CFR 58,
includes quality assurance and siting, and a quality
assurance program that has been approved by the
appropriate Regional Office. This is also stated in
the November 21 policy.
Page 19. "The Office of Air and Radiation needs to issue policy
to reduce the potential confusion and inconsistencies
in implementing the PM10 regulations.- We believe all
concerned parties need to be formally advised of
OAQPS'8 policy."
Response
As previously stated, OAQPS issued a policy memorandum
on November 21 to clarify the use of PM10 measurement See
data. Append!
Note II
Page 20. "In our opinion, both of the other two (Issue Paper)
options have merit, although criticism would be
expected from those who believe all measurements must
be treated as if they came from the same type of
monitor which always provided consistent measurement."
Response
The joint OAQPS/EMSL committee which consisted of E
national experts in PM10 instrumentation, PM10
monitoring, PM10 standards interpretation and PM10
standard's implementation determined that their See
recommended option was the best course of action. Appendix
~"' ' - Note 14
Page 20: "We believe that the Office of Air and Radiation should
establish a group or panel of experts who would deal
with specific situations on a case-by-case basis. For
example, in regard to the 24-hour standard, the panel
would be given the authority to decide whether .
measurements within a specified, rang* are to be
considered exceedances. The panel could consider all
information made available to it, such as the type of
monitor, the monitor's location, the amount of
difference between the measurement and the standard,
etc. This panel would document the reasons for its
decisions."
Response
OAQPS has determined that the best course of action is
to get a general policy for the interpretation of PM10
data and to consider exceptions as warranted on a case-
10
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APPENDIX 3
Page 19 of 86
by-case basis. We beleive that this approach See
emphasizes national uniformity. Appendix 4,
Note 15
Page 20. "Where appropriate, changes which are ultimately made
in current policies and procedures may need to be
submitted through the formal rulemaking process."
Response
The new OAQPS policy is stated as a general policy and
exceptions are permitted. We and OGC believe this
approach is lawful and provides a balance between
certainty and flexibility. If at some later time we
conclude it would be appropriate to adopt rules
incorporating these policies, EPA could then undertake
rulemaking.
Page 20. "The committee has recommended that PM10 measurements
be accepted at face value."
Response
This statement should be qualified to say that the
committee recommended that PM10 measurements from EPA Appendix i
approved reference method samplers be accepted at faceNote 16
value. '
Page 22. "In other words, in our opinion, no environmental
official, or combination of SIP officials, has clear
authority to decide that continuous, routine
measurements just above the standard should not
automatically be treated as exceedances, depending on
the type of monitor that generated the data."
— * >?- ~* - S*L . "-.» -iei i 4 —a
Response
The new OAQPS policy requires that when routine
measurements are consistently produced with a reference
sampTar above the standard, then these measurements
would oe judged as exceedances of the standard. Once a
sufficient number of such exceedances are observed,
then a nonattainment problem will be evident. This is
clearly indicated in Section 2.2 of the £H10 SIP
nsarelons^nt Guideline and is not superceded by the See
revised guidance. Appendix 4
Note 17
Page 22. "Similarly, in our opinion, no environmental officials
or combination of SIP officials has clear authority to
decide that continuous routine measurements just below
the standard should sometimes be treated as
exceedances. In any case, clear policy is needed, and
the authoritative basis for this policy needs to be
11
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APPENDIX 3
Page 20 of 36
Response
The revised OAQPS policy clearly states that "all data
produced by reference samplers shall be interpreted at
face value and can be used to make comparisons with the
NAAQS for the purposes of determining attainment or
nonattainment, in accordance with Appendix K to 40 CFR
50." Thus measurements just below the standard cannot
be treated as exceedances. See
Appendit
Page 22. "We believe that EPA can better define a policy which Note 11
allows knowledgeable professionals to interpret monitor
data, rather than a policy which categorically states
that all monitor measurements must be accepted at face
value."
Response
For the reasons discussed in our responses, we and OGC
believe that accepting data from reference monitors at
face value complies with applicable law and See
regulations. . In fact, this approach will present lessAPPe
serious legal problems than the IG's suggested approach Nc
of adjusting data from reference method monitors. As
the IG report notes, regulatory changes probably
have to be enacted to allow for the adjustment of
Page 23. IG Recommendation Number Is
"Establish procedures which allow for flexibility in
interpreting measurements near the PM10 standard."
Such as
(a) "establishing a panel of experts who would deal
with measurements within a specified range on a
case-by-case basis;"
(b) "not requiring any action for monitor measurements
within a certain "gray zone* around the standard;
and*
(c) "adjusting measurements by predetermined
percentages, depending on the type of monitor."
12
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APPENDIX 3
Page 2 lof 36
Response
We feel that the OAQPS policy on the face-value use of
reference measurement data, coupled with the PM10 SIP
process provide sufficient flexibility for
interpretation of measurements near the PM10 standard.
We feel that the appropriate role for a group of
experts is to review PM10 SIPS, and not to review all
measurements within a specified range. Although
options (b) and (c) above, were considered by the
OAQPS/EMSL committee, they could not -be recommended
after weighing and evaluating their various advantages
and disadvantages.
The use of all PM10 data produced by reference samplers
at face value is clearly the best course of action.see
Appendix 4,
Page 23. IG Recommendation Number 2s Note 19
"Establish procedures which provide for documenting the
basis for deciding an area's attainment status."
Response
The new implementation regulations for PM10 do not
require that an area's attainment status be
categorized. Instead, the implementation regulations
specify that an area's SIP is judged to be adequate or
inadequate to attain the standards. The SIP,
therefore, provides for the appropriate regulatory see
documentation. Appendix 4,
Note 20
Page 23. IG Recommendation Number 3s
"Work with appropriate EPA officials to obtain any
regulatory changes that are necessary to provide a
clear, authoritative basis for the selected policy."
Response
The November 21 policy memorandum issued by OAQPS to
the Regional Air Directors described and communicated
the proper use of PM10 measurement data. No regulatory
changes are needed. See
Appendix 4,
Note 21
13
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APPENDIX 3
Page 2 2. of 36
RESPONSES RELATED TO
AUDIT ITEM NUMBER 2 - "EPA NEEDS TO PROVIDE GUIDANCE AND
CLARIFY AUTHORITY FOR USING DATA FROM,
NONAPPROVED MONITORS"
Page 1. Objective - "to determine whether OAQPS has implemented
a policy to deal with the fact that most of the PM10
data which has been accumulated through 1988 is likely
to have been generated by types of monitors that have
not gone through the evaluation and approval process
required by regulations."
Response
OAQPS has implemented a policy to deal with the use of
PM10 measurement data produced by nonreference (i.e.
non-approved) samplers. This is contained in the
November 21 OAQPS policy memorandum. We differ with
the IG's statement, however, that most of the PM10 data
which has been accumulated through 1988 is likely to
have been generated by nonapproved monitors. The
response to this point will be discussed together with
our response to the third topic of the IG audit which
deals with the number of required PM10 monitors.
See our response to page 37 of the IG
Draft Report for this discussion.
Page 4. "We believe that current regulations do not clearly
allow this data to be used and recommend that the
regulations be clarified. Doing so will strengthen the
Agency's position should legal challenges arise.
Moreover, if adopted, the committee's recommendations
would change the present policy for interpreting
measurements from- nonapproved -monitors near the PM10
standard. Accordingly, we recommend that the Office of
Air and Radiation clarify its policy on this issue."
Response
We feel that the November 21 policy memorandum provides
the required clarification to the regulations. Jj*dix
Note 22
Page 24. "Most of the PM10 data accumulated through August 1,
1988.has been obtained from types of monitors that have
not been approved by EMSL's Methods Standardization
Branch (MSB).'
Response
As stated above, this will be answered in the response
to the third audit topic.
14
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APPENDIX 3
Page 2 3 of 86
Page 24. "Clarification of EPA policy and regulatory authority
for using data from nonapproved monitors will conserve
significant EPA resources that would otherwise be spent
dealing with the issue should legal challenges occur."
Response
The November 21 policy memorandum clarifies the use of
data from nonapproved monitors. See
Appendix 4,
Page 24. "Part 53 describes a very detailed and complicated Note 22
process by which MSB approves PM10 measurement methods.
For purposes of this report, it is sufficient to note
that the regulations require PM10 monitor types to be
approved by MSB..."
Response
Change MSB to EPA. Under 40 CFR Part 53, reference and
equivalent methods are formally approved by the EPA
Administrator or his designee. In this case this
authority has been delegated to the AA of ORD. This
error is made throughout the document and should be
corrected. See
Appendix 4,
Page 25. "Subsection titled "EPA has not approved some Note 23
monitors."
Response
This section has numerous errors in detail that will
not be corrected here. The Chief of MSB, however, will
be available to meet with the IG staff to provide them
with these corrections to ensure that the IG Final
Report-1« c^rrefcft. ^ • -, ^, See
Appendix 4,
Page 27. "We asked the Chief, MSB, whether any of the Noce 24
nonapproved monitors were likely to be submitted for
approval.1* """ ' • ^
Response
This paragraph contains several factual errors;
however, as indicated above, the Chief of MSB will be
available to meet with the IG staff to make these See
corrections to ensure that the IG Final Report is Appendix 4,
correct. Note 2S
Page 28. "In our opinion, 40 CFR 50.6(c), which we quoted on
page 24, does not clearly allow EPA to use PM10 data
from nonapproved monitors as the basis for deciding
that an area is out-of-attainment."
15
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APPEOTIX 3
Page 24 of 36
Response
OAR and OGC agree that the regulations as currently
written do not clearly allow EPA to use PM10 data from
nonapproved monitors. However, we do not agree that it
means that nonreference monitors may not be used for
purposes other than to supplement and corroborate data
collected by reference samplers where such data are
insufficient in quantity to make a determination of
whether or not the areas is attaining or not attaining
the standards. We feel that the current regulations
justify this usage. This is based in part, on the
exception clause in Appendix K which refers to existing
guidance and approval by the appropriate Regional
Administrator. The guidance (Guideline on Exceptions
to Data Requirements for Determining Attainment of
Particulate Matter Standard! discusses TSP as an
example for a surrogate particulate matter indicator.
The guideline states that other approaches are also
possible. This is discussed more fully in our See
responses to points raised on pages 31. Since the Appendix
regulations were not explicit on the usage of Note 26
nonreference PM10 data, however, some clarification was
needed. The November 21 policy memorandum provided
this clarification.
Page 29. "In our opinion, the present regulations do not
contemplate or allow data from nonapproved monitors fes*.
be used."
Response
As the audit report states on page 29, "we (OAQPS) feel
that the present regulations are1 broad enough to allow
data, outside a small range (+ or -20%) on either side
of the PM10 standard, to be used to corroborate both
positive and negative attainment decisions." see Appendix
Note 26
Page 29. ...the Issue Paper recommends that... "(2) measurements
within the gray zone should be disregarded; and (3)
measurements outside of the gray zone should be taken
at face value."
Response
For item (2), both the September draft and final
version of the Issue Paper stated that measurements
within the gray zone should not be disregarded but used
with less authority. For item (3) measurements outside
the gray zone should be considered more authorita-
tively. Specific formulas are provided in the November
16
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APPENDIX 3
Page 2 5 of 86
21 memorandum. In particular, when nonreference Sierra
Anderson or Wedding PM10 data are greater than their
respective gray zones, these measurements would be
treated as exceedances of the standard. Similarly,
when these data are less than their respective gray
zones, these data would not be counted as an See Appendix 4,
exceedance. Note 27
Page 31. "Our interpretation of Appendix K and the Guideline is
that they are referring to using data from certain
specific sources (or time), other than the primary
source (or time), but not data from nonapproved
monitors, to corroborate a positive attainment decision
(but not a negative attainment decision) that is
already firmly indicated by existing data from an
approve monitor.
Response
Section 2.3 of Appendix K states that 3 years of
monitoring data from approved reference method PM10
samplers normally are necessary to make a determination
that an area is not attaining the standard. But the
provision also provides an exception to this data
requirement: "Data not meeting these criteria may also
suffice to show attainment; however, such exceptions
will have to be approved by the appropriate Regional
Administrator in accordance with EPA guidance." As the
IG report notes, Appendix K does not expressly allow
the use of nonreference sampler data to corroborate
approved sampler data in determining that an area if in
attainment. It also does not preclude the use of
nonreference data for this purpose, however. Nor does
the Guideline's failure to address the subject mean
that it is not permitted. The Guideline on-Exceptions
to Data Requirements for Determining Attainment of
Particulate Matter Standards states that "the present
document is intended to provide guidance for such
exceptions to data requirements, bat it is not intended
to list all possible situation* in which data may be
acceptable); other procedures besides those described in
this guideline may be used to determine attainment of
the particulate matter standards, if approved by the
Regional Administrator.* The above statement is
emphasized to show that the guideline did not intend to
limit the type of data that could be considered. The
November 21 memorandum clearly clarifies that PM10 data
from nonapproved samplers may be used in a manner See
similar to that described for TSP in the guideline-Appendix
Page 31. "We do not believe the regulations or the Guideline No..e 26
allow data from nonapproved monitors to be used to help
corroborate data from approved monitors in making a
17
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APPENDIX 3
?a§e 2 6 of 36
negative attainment decision."
Response
It is true that under Appendix K, 3 years of data are
not needed for the Agency to determine that a
monitoring site is not in attainment with the PM10
standards. There are strong policy and common sense
reasons why nonreference data also should be used to
corroborate reference data in making nonattainment
determinations, however. Concern for human health and
welfare suggests that such data showing exceedances of-
the standards may reasonably be utilized to fill in
data gaps caused by the failure to use reference
instruments prior to August 1988. The language of
Appendix K, section 2.3 supports this view. It states
that "there are less stringent data requirements for
showing that a monitor has failed an attainment test
and thus has recorded a violation of the particulate
matter standards" than for showing that a monitoring
site has attained the standards. Moreover,
the source of measurement data needed to determine
nonattainment with the standards is not explicitly
specified in the regulations. While 40 CFR 50.61(c)
only refers to PM10 measurement methods for the purpose
of determining attainment of the standards, the
regulations often imply nonattainment in addition to
attainment as an intended use of measurement data.
Thus, we and OGC believe that we can use nonreference
data both for attainment and nonattainment purposes,
provided that they corroborate data produced by an
approved PM10 sampler. The November 21 policy memo
provides the necessary clarification regarding PM,0
data produced by nonapproved samplers to define the
manner in which these data can be used to corroborate
data from approved samplers for making both a positive
and a negative attainment (i.e. nonattainment) see
decision. Appendix 4
Note 28
Page 33. "The (OAQPS/BMSL) committee recommends that data from
nonapproved monitors in a gray zone near the standard
be ignored; however, we believe that the gray zone be
used .like a net to collect marginal data which would be
analyzed by a panel of experts who would be empowered
to decide whether an exceedance had occurred.*
18
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APPENDIX 3
Page 27 of 86
Response
The committee recommends and the November 21 memorandum
states that data from nonapproved monitors in a gray
zone near the standard not be ignored but be used with
less authority. Specifically, such 24-hour
measurements would be included in the calculation of
the annual mean. Furthermore, the policy governing the
use of data produced by nonapproved monitors can create
a situation in which sufficient reference and
nonreference data are not available to make an
unambiguous attainment or nonattainment determination.
Instead of asking a panel of experts to decide on the
air quality status, our approach recognizes that this
situation is too close to call and would require that
additional monitoring data be collected until an
unambiguous decision could be made. See Appendix A,
Note 29
Page 33. "The committee recommends that all measurements from
unapproved monitors after August 1, 1988 be ignored for
purposes of making attainment decisions while we
believe such measurements should be used if the monitor
was in service prior to that date."
Response . '
The committee recommendation and the November 21 policy
memorandum are consistent with 40 CFR 58 which
require that State and Local Air Monitoring Stations
(SLAMS) Networks be established by August 1, 1988; the
policy memorandum, therefore, stated that "data
collected after this date by nonreference samplers
shall not be used. If a nonreference sampler without
further modification is .designated as a reference
sampler in the future, then all of its historical data
is retroactively defined as data produced by a See
reference sampler." Appendix A,
Note 29
We felt compelled to write this- requirement to ensure
that existing nonreference samplers be upgraded or
replaced with samplers which comply with the PM10
monitoring regulations. As is discussed in our
response to the third audit issue, only a small number
of nonreference samplers are affected by this decision.
Page 33. 16 Recommendation Number Is
"Not allow data from a nonapproved monitor to be used
to determine exceedances if that data was obtained from
a monitor that was placed in service after August 1,
19
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APPENDIX 3
Page 23 of 36
Response
This is consistent with the November 21 policy see AD^RUX
memorandum. \jote 30
Page 34. IG Recommendation Number 2:
"Allow data that was acquired in the past, or is
acquired in the future, from a nonapproved monitor that
was part of the SLAMS or NAMS Network- that was being
used prior to August 1, 1988 to be considered by a
panel of experts as a basis for determining whether
exceedances have occurred."
Response
SLAMS and NAMS networks were only approved
conditionally if nonreference monitors were currently
being used. These monitors are supposed to be replaced
or upgraded with reference samplers after August 1,
1988. If we were to allow data from nonapproved
monitors to continue to be used, then we remove the
incentive for the monitoring agencies to upgrade or
replace these samplers. According to the November 21
policy, data from nonapproved monitors that were
collected prior to August 1, 1988 can ba used, subject
to tha approach specified in the memorandum. Data
collected after August 1, 1988 cannot ba usad, unl<
tha monitor is subsequently approved by EPA.
Page 34. IG Recommendation Number 3:
"Allow measurements from such nonapproved monitors
(monitors that wara part of tha SLAMS and NAMS network
prior to August 1, 1988) to ba traatad lika data from
approved monitors, for purposes of making attainment
decisions, whan tha PM10 measurements ara graatly above
or balow tha PM10 standard (as illustrated by tha data
from Madford, Oregon); tha cutoff points around tha
standard may ba decided by tha panal of experts."
In our November 21 memorandum, an analogous approach
was, in fact, astablishad. Our approach is to sat a
ganaral gray sona within which nonrafaranca PM10 data
would ba viawad with uncart ainty and outsida of which
tha data would ba usad with more authority.
Tha gray sona limits speciflad in tha November 21
>randum wara recommended by tha OAQPS/BMSL committd
20
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.APPENDIX 3
Page 29 of 86
of PM10 experts
Page 34. "Allow a panel of experts to be flexible in deciding
whether monitor measurements near the standard should
be treated as exceedances, depending on the type of
monitor, the amount of differences between the
measurement and the standard, etc."
Response
A uniform interpretation of PM10 data-for all
monitoring areas is preferable to one which varies from
area to area. With a uniform approach, the procedures
are defined in advance. This permits a consistent,
more unbiased interpretation of available PM10 data.
We agree that flexibility is needed in order to make
comparisons with the standards, but prefer to do so by
permitting exceptions to a general approach.
Page 34. IG Recommendation Number 5s
*
"Work with appropriate EPA officials to obtain the
regulatory changes that are necessary to implement the
selected plan of action including, if appropriate, the
modification of 40 CFR Part 50.6(c), which does not
clearly allow the use of any data from a monitor not
approved by MSB in the determination of whether
exceedances have occurred."
Response
As previously discussed, while 40 CFR 50.6(c) and
Appendix K do not clearly allow the use of nonreference
data for corroborative purposes, they also do not
disallow, the us* ot-tfee- data, in this jiannar* -It time
were not a factor, we would agree that revising section
50.6(c) to clearly and expressly permit the Agency to
consider nonreference data in staking attaiiuMnt
decisions Bight, prove the test course. Amending the
regulations would resove any ambiguity that now exists
regarding our reliance on Appendix K. It would also
require BPA to undertake full notice and cossssnt
jcmleaaking, however. That process could take years.
-9m. the 10 report points out, reference method Monitors
sjsjgs required to b« in place by August 1988. There
exists ths> distinct possibility that the Agency would
have 3 ysars of data frosi approved monitors across the
country by the time it finally prosnilgatad a revision
to the regulations that would allow the use of
nonreference data whan lass than 3 years) of data from
an approved monitor was available. Thus, the
rulasiaking could prove pointless.
21
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'APPENDIX 3
Page 30 of 36
Given the practical impediments to revising section
50.6(c), we believe that the best course is the one
embodied in the November 21, 1988 Revision to Pol icy
the Use of PM10 Measurement Data. It is fair, sensib
and legally defensible. While it provides a general
framework for using nonreference data, it also provides
sufficient flexibility in that OAQPS approved
exceptions are permitted. Moreover, it may be
implemented immediately.
•
Page 34. IG Recommendation Number 6
"Communicate EPA policy to State and local officials
through the regional offices."
Response
This has already been accomplished with the November 21
policy memorandum to the Regional Air Directors. See
Note 30
22
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APPENDIX 3
Page 3 1 of 86
RESPONSES RELATED TO
AUDIT ITEM NUMBER 3 - "ADDITIONAL PM10 MONITORS ARE NEEDED
AND EPA NEEDS TO TAKE A MORE ACTIVE
ROLE TO ENSURE THAT MONITOR REQUIREMENTS
ARE MET"
Page 5. "In our opinion, the precise number of monitors that
were needed at a point in time is less important than
the effort that is being made to ensure that the need
for future PM10 monitors is accurately assessed and
met." Subsequently, the 16 estimated that 81 PM10
samplers would be needed to provide full coverage for
the PM10 network. This premise is discussed from
different perspectives such ass (a) replacement or
modification on non-approved samplers, (b) shifting
resources from TSP to PM10 monitoring, (c) moving PM10
samplers from Group III to Group I and II areas, and
funding for new PM10 samplers.
Response
The statement above strongly implies ineffective action
by OAQPS in assessing future PM10 sampling needs and
ensuring that these needs are met. The report then
proceeds on an exhaustive detailed 23 page description
of a March 1988 short fall of 81 PM10 samplers which
OAQPS had identified and included in their preliminary
draft PM10 status report of January 25, 1988, which was
given to the IG auditors. Since additional PM10
samplers were purchased after March 1988, the IG
auditors were provided with updated information by
OAQPS on October 12, 1988 by memo and meeting. This
information showed that only four PM10 samplers were
needed to- fully cover all Group I and II areas as well
as meeting all of the NAMS requirements'. The IG draft
audit report did not fully utilize the material
provided on October 12 but instead focussed on an
outdated estimate of an 81 monitor shortfall. See Appendix 4,
Note 31
Page 35. "The PMio Monitoring network needs more monitors, but
the exact number of needed monitor* could not be
determined from the information available at the time
we concluded our review.*
mespenae
This statement disregards the tabular information OAQPS
provided the 16 auditors on October 12, 1988, which
showed that as of October 1988, only four PM10 samplers
were needed to fully implement the PM10 network. This
was based on the assumption that all of the first year
nitoring requirements for the Group I and II areas as
23
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APPENDIX 3
Page
well as the minimum number of NAMS were met or were
very close to being met without additional PM10 samplers
being located in the monitoring area. Additional
assumptions were based on the urbanized population,
magnitude of the concentrations, PM10 area monitor
groupings, and expectation that reference status would
be granted in the near future for the Oregon sampler
and the SA dichot.
It should be noted that OAQPS has tracked and published
periodic status reports on the PM^ networks. A total
of 13 reports have been issued, the first of which was
issued in February 1985 and showed that 117 PMto
samplers were operational as of December 1984. The 16
report was using information which was presented in the
Status Report Number 12 dated November 1987 and
reflected the status as of September 1987. This report
showed that there were 884 PM^ samplers operating at
550 sites.
During discussions between OAQPS and the IG during
1988, the IG auditors were given prepublication
information on the next PMW network report which would
show the status as of March 1988. The IG auditors
calculated from this information that as of that date,
81 PMM samplers would be needed for the network to be
fully implemented based on the Part 58 monitoring
regulation requirements. OAQPS concurred that 81
additional PNU samplers were needed as of March 1988.'
The focus of this discussion is to point out that OAQPS
has been tracking the requirements and locations of the
PM10 samplers for over 4 years. During this time,
samplers were purchased in three ways: (a) by EPA
directly and given to the States, (b) through the 105
Grant process, and (c) by the State/local agencies
direct purchase of samplers with their own funds.
As a result, the PMi( networks have grown in size from
117 samplers in 1984 to over 1,000 in 1989. Therefore,
in the spirit of cooperation between OAQPS and the IG
auditors, OAQPS as noted earlier, provided the IG
auditors with the OAQPS latest information on October
12, 1988 at a meeting and by draft memo. This
information and analysis showed that 11 samplers were
needed to fully implement the PMU network, and 7 of
these> 11 samplers were in the process of being ordered.
Therefore, OAQPS concluded that the shortfall in
October 1988 was 4, and not the 81 samplers the IG used
in the report. This was clearly stated in the draft
memo. However, this information was largely
disregarded by the IG auditors, who proceeded to write
another 23 pages on the subject. See Appendix
Note 31
24
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APPENDIX 3
Page 33 of 86
While the four PM10 samplers would complete the
-_ monitor ing network for existing Group I and II areas as
well as the NAMS requirements, it must be understood
that new areas may be identified in the future, so that
additional samplers may be needed. The PM10 Monitoring
Task Force is currently looking into this problem.
Page 35. "As described in Exhibit B, we estimated that a minimum
of 81 additional monitors were needed on August 1,
1988. This shortfall consisted of 66 monitors which
were needed in locations that did not-have enough
monitors, and 15 monitors which were needed to replace,
or be collocated with, types of monitors that had not
been reviewed and approved by EPA."
Response
As discussed above, we are concerned with the 16's
draft report focus on the outdated August 1, 1988,
estimate of an 81 monitor shortfall. OAQPS informed
the 16 auditors on October 12, 1988, that only four
additional PMM samplers were needed. He are concerned
that this information was largely disregarded.
Also, the 16 auditors ignored information provided to
them on October 12, 1988 that 573 PM,. sites out of the
603 PMu sites identified by the 16 auditors were using
reference samplers. The remaining 30 samplers were in
the process of being evaluated for reference status.
The approval for the Oregon medium volume PMj, sampler
and the SA dichot should be granted by mid 1989.
Furthermore, in meetings with the IG auditors, the
OAQPS staff, it was explained that most of the non-
reference samplers identified by the 16 auditors were
reference samplers. The situation was simply a coding
problem (the data from reference PNU samplers were
incorrectly coded as non-reference samplers) and steps
were being taken to correct this situation. Some of
the procedures have already been implemented. However,
the 16 auditors again did not acknowledge the See
information provided by OAQPS. Appendix 4,
Note 31
Page 36. "However, we do not agree that only 11 sites still
needsd PM^ monitors because the Branch Chief: (1)
asttnmed that EPA will approve some monitors and (2) did
not mention that OAQPS itself believes that 50 to 100
additional monitors are needed for spares, training,
and special studies."
25
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APPENDIX 3
3 - of 36
Response
In our October 12, 1988 draft memo, the OAQPS position
was that there were only 30 non-approved samplers in
operation (later revised to 28) and that these would be
approved by EPA in 1988. We maintain that position
except that the approval has been slightly delayed.
The SA 254 medium volume samplers are scheduled to be
approved in March 1989 and the SA dichot in April 1989.
Concerning the estimate of an additional 50-100
samplers for spares, training, or special studies, the
OAQPS status reports on the PM*, networks have tracked
the number and locations of PM^ samplers needed to
complete the network, but have never intended to keep
track of all the PM10 samplers being used for spares,
training, special studies, etc. The spares are not a
trackable item, because most of the time only the
broken part is replaced and not the complete sampler.
OAQPS is keeping track of the samplers being used for
special purpose monitoring. The question asked was how
many PMt, samplers were needed in October 1988 to fully
implement the PMU networks. This question was see
accurately answered. Appendix 4,
Note 31
Page 36. "He are less concerned with the precise number of
monitors that were needed at a particular point in the
past than in the efforts that will be made to
anticipate and meet future monitoring needs in the
constantly changing PMW environment." Then for the
next nine pages, they discuss (a) the role of OAQPS in
assigning resources to areas with greater PM*, problems,
(b) replacement of non-approved monitors, (c) shifting
resources from TSP monitoring to-PM10 monitoring, (d)
shifting PM^ samplers from Group III to Group I and II
areas, and (e) funding of PMU samplers.
Response
The IG report, as stated previously, fails to
acknowledge the fact that as of October 1988, only 11
PMj. samplers were needed to fully implement the PM,.
networks, and 7 of the 11 samplers were in the process
of being purchased. Also as noted previously, PM^
samplers have continually been added to the network
since 1984. The latest OAQPS PMU status report showed
914 samplers operating in March 1988. Since then,
preliminary information for the next PMlt status report
show that approximately 150-200 new PMt, samplers have
been, or are in the process of being, purchased.
26
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APPENDIX 3
Page 35 of 86
Two of these new PM10 samplers are targeted for the two
Ohio counties which were identified as having
inadequate sampling frequency. These PM10 samplers will
be operational by September 1989. Also, Connecticut
has purchased samplers for multiple sites in Fairfield
County to provide coverage and are operating these
sites on a l-in-6 day schedule as of October 1988 (but
not at the required every day schedule). It may
therefore be concluded that based on available
information, the PM^ networks will satisfy current
requirements by September 1989 except for Fairfield
County, Connecticut. See Appendix 4,
Note 31
Page 37. "We concluded that OAQPS has not fully assessed the
need, or confirmed that an assessment has been made of
the need, to modify or replace non-approved monitors
that are part of the current SLAMS and NANS network."
Response
OAQPS strongly disagrees with the IG draft report
conclusion. As pointed out in page 4 of the draft memo
given to the 16 auditors on October 12, 1988, of the
603 PMu sites identified by the IG auditors, 573 PM\.
sites are using reference samplers. Twenty-eight of
the remaining 30 sites were using samplers for which
reference designation was applied for. As noted above
and in discussions with the 1C auditors, it was
explained that this perceived problem was simply a
coding problem and steps would be taken to correct this
situation. On page 6 of the memo to the 16 auditors on
October 12, 1988, it clearly states that "the problem
of unapproved monitors has been resolved." It is not
clear why the 16 auditors have chosen to ignore the EPA
information.
A summary of the OAQPS actions taken to address the
coding problems are discussed below:
(a) Old PM» samplers with method codes 055, 056, 057,
OS9* and 05t were in fact reference methods and should
no* have been counted as non-approved samplers. The 16
Ltors were informed of this in the October 12, 1988
On January 3, 1989, data from samplers with
codas must be submitted under reference method
062, 063, 064, and 065.
(b) The data stored in AIRS under method codes 055,
058, and 059 prior to January 3, 1989 will be converted
by the National Air Data Branch (NADB) in the next
several weeks to the reference method codes 062, 063,
and 064.
27
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APPENDIX 3
Page 36 of 36
(c) The agencies collecting the PM10 data are being
requested to convert method codes 056 and 057 to the
reference methods 064 and 065. This is because two
PMia modifications were installed and only the
collecting agency knows when the modifications were
completed.
(d) PM10 samplers with method codes 051, 052, 053, and
054 have all been modified to be reference methods, see Append
Note 32
Page 38. "We asked the Section Chief how many States still had
laws that required TSP monitoring. The Section Chief
could not tell us."
Response
The 16 auditors were informed that OAQPS was in the
process of obtaining this information but that all of
the responses were not back at that tine. The
following information was obtained from the Regional
Offices on the 36 States which have retained at least
some part of the TSP standard:
Region I- CT, MB, MA, NH, RI, VT
Region II- NJ, NY, PR
Region III- DE, MD, VA, WV
Region IV- AL, PL, GA, KY, MS, MC, SC, TN
Region V- WI
Region VI- MM
Region VII- NE
Region VIII- CO, MT, SO, UT, WY
Region IX- AZ, HI, NV
Region X- AK, ID, OR, HA
It should be noted that a cutback in TSP sampling will
result in SOB* savings on manpower but not on capital
expenditures for PMM equipment. See Appendix 4,
Note 33
Page 38. "Based on our conversations, we concluded that although
OAQPS had set goals for disinvestment, it had not
gathered information about State TSP monitoring laws
which would have been helpful in formulating reasonable
goals for States and local agencies' reductions in TSP
monitoring. We further concluded that OAQPS had not
mad* a significant effort to encourage, or find out
about, State or local offices' efforts to make any
changes in TSP monitoring that may appear to be
warranted." The IG report also questions in a round
about way how EPA estimated that 600 to 700 TSP
samplers would be needed for future purposes.
28
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APPENDIX 3
Page 37 of 86
Response
There were 2028 TSP SLAMS and NAMS samplers operating
in December 1987 as shown in the OAQPS annual SLAMS
status report. Preliminary estimates in January 1988
were that 1676 TSP samplers would continue to run in
1988. However, the Director of the OAQPS Technical
Support Division asked each Region to reevaluate the
projections for the 1988 SLAMS networks since OAQPS
estimated that only 600 to 700 TSP samplers would be
needed for various reasons. These TSP sanplers would
be needed for (a) surrogates for PM^, (b) National
Particulate Network (NPN) analyses, (c). collocation for
1 year with PMlt NAMS, (d) sampling in States with a TSP
standard, and (e) maintaining an ability to conduct a
national trend analysis of TSP based on a greatly
reduced number of samplers.
«
The IG draft report chose to focus on how many States
had a TSP standard and whether OAQPS had considered
this number in estimating that 600 to 700 SLAMS
samplers would be needed. The OAQPS did have some
information from various Regions on which States had a
TSP standard. This information was factored, along
with OAQPS estimates, on what the SLAMS TSP network
would shrink to.
The revised TSP number for 1988 based on the
reevaluation of needs resulted in 1542 planned to be
operated in 1988. Because of the cooperation of the
Regions, States, and local agencies, this number had
been reduced to approximately 1050 by the end of 1988.
Furthermore, the preliminary projections for 1989 are
for 800 to 850 TSP samplers to be operating.
Projections for 1990 show that the original projections
of 600 to 700 TSP samplers will probably be achieved.
The above discussion shows that resources at the State
and local levels are being shifted from TSP sampling to
PM,, samplingk Also, there is a reasonably good chance
that the OAQPS target was realistic and will probably
b»achieved in 1990. However, what is implied in the
ia report is that as resources are decreased from TSP
sampling, more resources would be available for
procurement of PM*. samplers to meet the IG deficit of
81 samplers. While some manpower would be shifted to
the PNu monitoring program, it will not provide the
resources needed to purchase PM^ samplers, balances,
upgrading weighing rooms, etc. S*« Appendix 4.
Not* 34
Page 40. "We have not seen any written communication, or been
advised of detailed verbal communications, which
29
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APPENDIX 3
Page 3-5 of 36
indicated to us that the strategy of shifting monitors
to meet regulatory requirements has been pursued to the
degree that we believe it should have been pursued."
Response
We disagree with this statement. OAQPS recommendations
to provide coverage in the Group I and II areas as
needed were included in the last several PM10 Status
Reports. Also, a memo was sent from the Director, TSD,
OAQPS to the Regional Office BSD Directors to re-
emphasize this recommendation. (See Attachment E.)
Most State/local agencies chose not to relocate PM10
samplers, since plans were underway to cover the
remaining areas with new PMlt samplers. See Appendix 4,
Note 35
Page 41. "...OAQPS does not know whether State, local, or
Federal funds will be used to purchase needed PMi(
monitors....".
Response
This section of the IG draft report is based on the
implication that 81 PM1( samplers are needed to fully
implement the PMt, networks. As stated repeatedly,
however, we informed the IG auditors that only four PMM
samplers were needed as of October 1988.
In discussing needed PNM samplers with the Regional
Offices, it was evident that PNt, samplers were being
purchased from a combination of Federal, State, and
local funds, and that the States and local agencies
were making the effort and resources available to fully
implement the PM10 networks. The previous discussion
indicated that in addition to the 914 PM*. samplers
operating in March 1988, preliminary estimates show
that-150-200 new PMW samplers have been, or are in the
process of being, purchased. See Appendix 4,
Mote 36
41. "During the audit, we discussed with OAQPS officials
those issues which we believe should be addressed in
their analysis. They are as follows:"
(1) "Locations where PM», monitors are required by
regulations (this information can be determined from
MRB's Status Reports)."
Response
The OAQPS'plans to continue issuing periodic PM», status
reports which will contain this information.
30
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APPENDIX 3
Page 39 of 86
(2) "Locations where PM10 monitors are currently
operating (this information is routinely presented in
MRB's Status Reports)."
Response
The periodic PM10 status reports will continue to
contain this information.
(3) "Locations where non-approved monitors are
operating."
Response
OAQPS does not believe that this is a significant
issue. As explained in an earlier discussion, all
operating PMlt samplers have been modified as needed
except as noted below. Reference status has been
applied for the SA medium volume and SA dichot sampler,
which represents 28 of the 60S PM^ samplers identified
in Exhibit A of the 16 report. There was also one GMtf
and one W-10 dichot also identified in Exhibit A, which
are not reference samplers. Therefore, 603 of 60S PMj.
samplers identified by the IG auditors as of May 1988
were expected to be reference samplers. See Appendix 4,
Note 37
(4) "Location where a type of non-approved monitor is
operating which can be modified to become a type of
sampler that can be approved."
Response
The two PMt. samplers discussed in item 3 above can not
be modified at the present time to become reference
samplers and will not be used in the NANS networks.
(5) -"Locations where FMU monitors are currently
operating, but are not, required to be operating by
Federal Regulations."
the PMt. samplers are not explicitly required
Part 58 Regulations in all Group III areas, the
regulations do not preclude the establishment of PH*,
samplers in these areas. The Part 58 Regulations allow
for PM,. samplers to be operated for SLAMS, NANS, or SPM
purposes. Appendix D of the Part 58 Regulations
specifies that the SLAMS network should be designed to
meet one of the four basic monitoring objectives.
These basic monitoring objectives are: (a) to
determine highest concentrations expected to occur in
31
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APPENDIX 3
Page -C of 35
the area covered by the network, (b) to determine
representative concentrations in areas covered by the
network, (c) to determine the impact on ambient
pollution levels of significant sources or source
categories, and (d) to determine general background
concentration levels. All of the PM10 sampling sites
OAQPS is tracking fall into one of these categories.
It appears that the IG investigators did not critically
review the valid monitoring objectives allowed by the
Part 58 Regulations.
OAQPS does not attempt to keep track of private or
industrial PM^ sites. The 16 auditors, by implication,
still believe that 81 PM10 samplers are needed contrary
to the information we provided to them, and that PMit
samplers should be relocated from areas where PM^
sampling is not required (according to the IG) to other
areas where it is-required. OAQPS strongly disagrees
with the IG draft report implication. See Appendix 4,
Note 38
(6) "Explanation of why monitors cannot be shifted from
locations where they are not required by Federal
regulations to locations where they are required (a
specific explanation should be identifiable to each
monitor that continues to operate where Federal
regulations do not require a monitor)."
Response
In light of the preceding discussion, we don't believe
further explanation is needed. Furthermore, the
critical areas are covered with PM10 samplers. See Appendix 4,
Note 38
(7) "Projections on when existing monitors will need to
be replaced because of aging."
Response
Whole PNU samplers are not replaced because of aging.
Component parts, such as brushes, motors, timers,
extension cords, etc., may have to be replaced over
time. The housing itself may never have to be
replaced. State and local agencies usually maintain a
supply of the critical parts for quick replacement for
these PMu high volume samplers. This is not the case
with continuous gaseous monitors. Sce Appendix
Note 39
(8) "Prioritization of where monitors are not needed."
32
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APPENDIX 3
Page 41 of 86
Response
Before the PM10 networks were fully implemented, OAQPS
repeatedly gave guidance to provide coverage in the
Group I areas and the Group II areas with the higher
likelihood of not attaining the NAAQS. However, the IG
auditors should refer to item (5) above which explains
that PM10 samplers are needed to meet different
monitoring objectives. The IG auditors apparently
believe that PM10 samplers should only'be located to
measure in maximum concentration areas. This is,
however, contrary to the Part 58 Regulations. See Appendix 4,
Note 38
(9) " Evaluation of whether TSP monitoring would be of
some use at locations without a sampler.n
Response
The Part 58 Regulations allow for the use of surrogate
TSP samplers as a part of the SLAMS network. There are
valid uses for these surrogates although only a few
have been designated as such.
(10) " Summary of expectations that new funds will be
obtained to purchase additional PM^ monitors
(expectations of local and State officials)."
Response
In addition to the EPA procurement of 662 PM10 samplers
in 1984, EPA recommended in their FY-86, FY-87, and FY-
88 grant allocations to the Regions the use of $400,000
to purchase other PM10 monitoring equipment. As
discussed earlier, the Agency finds that except for two
PM10 samplers in Region I, the PM^ monitoring needs in
all Group I and Group II areas as well as the NAMS
requirements have been satisfied. The Agency
recognizes that there ,is a need for short term
saturation PMU sampling in potential problem areas not
covered with PN10 samplers, for example in areas where
extensive wood burning occurs. A FY-90 initiative is
being developed which would enable each Regional office
to conduct 3-7 PM10 saturation studies per year.
Findings from these studies may demonstrate the need to
establish permanent PM^ reference method samplers in
these problem areas. The initiative would include
resource needs to correct these network deficiencies.
(11) "Summary of expectations for reallocation of funds
from TSP monitoring to PM10 monitoring."
33
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APPENDIX 3
Page 42 of 36
Response
In the earlier discussion concerning shifting resources
for TSP to PM10 sampling, OAQPS projects that 800-850
TSP NAMS and SLAMS samplers will be operating in 1989
and probably close to 700 in 1990. (See the second
response to page 38 of the IG Draft Report.) This
reduction will not result in any capital funds for PM18
sampler procurement, but will free up resources to
operate the PMto network. It should be noted that in
1984 when EPA purchased the 662 PM10 samplers, there
were approximately 2500 TSP monitoring sites as
compared to 800-850 TSP sites in 1989.
(12) "Identity of States with laws that require TSP
monitoring; expectations of officials for revisions in
such laws; etc."
< t
Response
As noted in the responses to pages 37 and 38, this has
been completed.
(13) "Summary of pending developments that may impact
on monitor needs (for example, prospect of improvements
in technology so that only one monitor is needed to
accomplish daily sampling."
Response
40 CFR Part 53 includes provisions for approving
alternative monitoring techniques such as continuous or
sequential samplers. The Ambient Methods
Standardization Branch of ORD administers and
implements these provisions. In this capacity they
have actively encouraged vendors of PMu equipment to
pursue development and formal testing of improvements
to current inlets, easier to operate samplers, and
continuous and sequential PM10 samplers. The continuous
and sequential samplers would provide a solution to the
PNu daily sampling requirement. Several manufactures
are currently testing their continuous sequential
samplers and if they meet the performance requirements
of Part 53, they will be designated equivalent methods.
To further encourage vendors to test and seeX approval
of their continuous or sequential samplers, the AMSB,
ORD has established a field test site in Birmingham, AL
to provide vendors the opportunity to compare their
samplers to EPA reference methods under field
conditions.
34
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APPENDIX 3
Page A3 of 86
(14) "Comparative analysis of PM10 monitor needs by
region (i.e., do certain regions appear to need
comparatively more monitors only because they have done
a more thorough job of identifying areas with potential
PM10 problems?"
Response
As noted many times throughout the OAQPS response, and
specifically the response to the last -paragraph on page
36 of the IG report, the deficit in October 1988 was
four samplers. PM^ samplers will be deployed by
September 1989 for the two areas in Ohio which did not
meet the minimum sampling frequency. This leaves only
Fairfield County, Connecticut which is not sampling at
the every day frequency. The Connecticut strategy is
to sample at several locations for 1 year and then a
review will be made of the data. They plan to increase
the sampling frequency at the worst site if needed, or
to apply for a reclassification of the area to Group II
or III.
35
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APPENDIX 3
Page 44 of 86
Page 45. (1) "We recommend that the Acting Administrator for Air
and Radiation ensure that a comprehensive analysis is
completed of PM10 monitor needs which includes an
assessment of the questions we have raised."
Response
OAR believes that it has conducted a thorough analysis
of the PM10 monitoring needs. We strongly disagree with
the draft report's contrary implication for the
following reasons. As early as 1983 OAQPS conducted a
critical review of the existing TSP and PM18 data in an
effort to identify those areas of the country having
high probabilities of exceeding certain PM19
concentrations. These areas were then used as the
basis for planning PM10 monitoring needs and calculating
the resources necessary to meet these needs. These
analyses were included in the Part 58 monitoring
docket. As new data entered the national air data bank
the critical areas were revised along with the PM^
monitoring resources. Tracking of these critical areas
continued and in February 1985 OAQPS issued the first
of 13 PM18 monitoring status reports. The 14th PM^
status report is in the process of being completed. In
addition to the status reports OAQPS also tracked, the
Regions' progress in establishing PH^ samplers in the
critical need areas through the Administrator's
strategic planning and management system (SPMS).
Independent of the 16's efforts, OAQPS initiated a PMla
monitoring task force to investigate the PM^ monitoring
efforts. The results of these findings will be used to
better identify PMto monitoring deficiencies. OAQPS
believes that this effort along with its ongoing status
report satisfies the IG's recommendation, see Appendix 4,
Note 40
(2) "We recommend that the Acting Administrator for
Air -and Radiation require that the analysis be updated
on a regular basis in accordance with a specific
timetable."
Response
OAQPS plans to continue issuing the PMia status reports
at least over the short term, as well as making a more
comprehensive analysis as needed. see Appendix 4,
Note 40
36
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Attachment B APPENDIX 3
,tosr, ' Page 4^ °f 86
?*£±\ UNITED J1TATES ENVIRONMENTAL PROTECTION AGENCY
•V
^
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 2771 1
r2l NOV 1988
MEMORANDUM
SUBJECT: Revision to Policy on the Use of PM10 Measurement Data
FROM: Gerald A. Emison, Director
Office of Air Quality Planning and Standards (MD-10)
TO: See Attached List ^
A joint Office of Air Quality Planning and Standards
(OAQPS)/Environmental Monitoring Systems Laboratory (EMSL)
committee has evaluated the issue of potential uncertainty in
measurement data produced by PM^ samplers. They considered
modifications and/or clarifications to existing Environmental
Protection Agency (EPA) policy contained in the EM10_SIE
Development Guideline (Section 2.3), the supplementary Response
to Questions Regarding PM,. State Implementation Plan (SIP)
Development (published June 1988), and the data requirements of
Appendix K to 40 CFR 50 and Part 58. This committee's issue
paper which incorporated comments from Regional staff is
attached. This memo follows their recommendations and presents
the revised EPA policy regarding the treatment of PM18 data
produced by reference and nonreference PM*, samplers. Treatment
of data produced by collocated PMto samplers is also discussed.
Deviations to this general policy must receive concurrence of
OAQPS.
For this discussion, the term reference sampler shall be
used to represent samplers using a reference method based on
Appendix J to 40 CFR 50 and designated by EPA in accordance
with 40 CFR 53, as well as samplers using an equivalent method
designated by EPA in accordance with 40 CFR 53. Nonreference .
samplers are all. other PM^ samplers which have not been
formally designated as such.
USE OF REFERENCE AND MONREFERENCB SAMPLER DATA
For purposes of evaluating PMta air quality status, all
data produced by reference samplers shall be interpreted at
face value and can be used to make comparisons with the
National Ambient Air Quality Standards (NAAQS) for the purposes
of determining attainment or nonattainment, in accordance with
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APPENDIX 3
Page 46 of 86
Appendix K to 40 CFR 50. Data collected by nonreference
samplers may only be used to supplement and to corroborate data
collected by reference samplers where such data are
insufficient in quantity to make a determination of whether or
not the area is attaining or not attaining the standard.
Moreover, data collected by some nonreference PM10 samplers
shall be interpreted using gray zones to indicate the potential
uncertainty in these older data, which was the policy used for
determination of Group I, II and III areas. These details for
using data produced by nonreference samplers in order to
interpret status with respect to the 24-hour and annual NAAQS
are contained in Attachment A. Three situations are discussed:
attainment, nonattainment and indeterminate. The latter
situation is one in which sufficient reference and nonreference
data are not available to make an unambiguous attainment or
nonattainment determination.
Regulations in 40 CFR 58 require that State and Local
Air Monitoring Stations (SLAMS) Networks be established by
August 1, 1988; therefore, data collected after this date by
nonreference samplers shall not be used. If a nonreference -
sampler without further modification is designated as a
reference sampler in the future, then all of its historical
data is retroactively defined as data produced by a reference
sampler.
A table providing a general overview of this new policy
for interpretation of PM^ measurement data is included as
Attachment B. The treatment of reference and nonreference data
is described according to the dates associated with its
collection.
COLLOCATED PM^ SAMPLERS
In the event that more than one PM10 sampler is operating
concurrently at a location, data from reference method samplers
always takes precedence over data from nonreference samplers.
If multiple samplers are collocated for data quality assessment
purposes (i.e., precision and accuracy), similar sampler types
must be used and one sampler must be designated a priori for
data reporting purposes (Appendix A to 40 CFR 58). Further-
more, if more than one type of sampler is used by a reporting
organization, collocated precision sites should be established
for each sampler type.
In order to sample more frequently than every 6* day, more
than one sampler may be operated at a monitoring site. This
group of samplers, plus any samplers sited for data quality
assessment purposes, shall represent a single monitoring
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APPENDIX 3
Page 47 of 86
station. When more than one sampler (or group) is operated
independently by one or more monitoring agencies concurrently
for attainment assessment purposes, each sampler (or group)
shall represent a different monitoring station. The data from
each monitoring station shall be used separately to assess
attainment or nonattainment with the NAAQS, provided that
the data meet all the requirements for SLAMS specified in
40 CFR 58, includes quality assurance and siting, and a quality
assurance program that has been approved by the appropriate
Regional Office.
Attachments
Addressees:
Director, Air Management Division, Regions I, III, IX
Director, Air and Waste Management Division, Region II
Director, Air, Pesticides and Toxics Management Division,
Region IV
Director, Air and Radiation Division, Region V
Director, Air, Pesticides and Toxics Division, Region VI
Director, Air and Toxics Division, Regions VII, VIII, X
Director, Environmental Services Division, Regions I-VIII, X
Director, Office of Policy and Management, Region IX
cc. G. Foley, AREAL
A. Eckert, OGC
bcc. D. Novello, OGC
J. Bachmann (MD-11)
PM10 Measurement Data Working Group
PM10 Monitoring Contacts
PM10 SIP Contacts
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ATTACHMENT A:
USE OF NONREFERENCE PMltt DATA TO SUPPORT AND CORROBORATE
REFERENCE PM.. DATA
COMPARISONS WITH THE 24-HR NAAQS
Data produced by nonreference samplers nay be interpreted
subject to the following conditions: (1) Exceedances measured
with certain PM^ dichotomous samplers1 shall be treated the
same as exceedances measured with reference or equivalent
method samplers, but only when there also are one or more
exceedances subsequently measured with reference samplers at
the same location. (2) Data produced with other nonreference
samplers shall be interpreted using gray zones (as previously
defined in the PM^ SIP Development Guideline and which were
used for SIP area grouping)' as follows - (a) an exceedance
measured with a nonreference sampler outside its gray zone can
be treated as an exceedance of the NAAQS, only when there also
are one or more exceedances subsequently measured with
reference samplers at the same location, and (b) a PM10 value
produced by a nonreference sampler which is in its gray zone is
not treated as an exceedance of the NAAQS nor is it treated as
a nonexceedance of the NAAQS (i.e. it is treated as an
uncertain data value for purposes of making comparisons with
the NAAQS), but it does count as a measurement used to satisfy
data completeness and compute annual averages.
Accordingly, data produced by nonreference method samplers
in combination with data produced with reference method
samplers may be used to identify the following situations:
24-hr NAAOS - Attainment Situation
If (1) the total number of observed
' exceedances measured by reference and
nonreference samplers results in an estimated
number of exceeedances to be less than or
equal to one (subject to the rounding
conventions and adjustments specified in
Appendix K), (2) uncertain data values
produced by nonreference samplers as defined
above do not exist, and (3) the combined data
produced by these samplers satisfy the data
completeness requirements in Appendix K and
are in accordance with the established EPA
guidelines, i.e. Guideline on Exceptions to
Data Requirements for Determining Attainment
of Particulate Matter'Standards (EPA-450/4-
87-005, April 1987), then the State can
'Samplers with inlet models SA246B, GMW9200 and WA10.
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solicit approval by the appropriate Regional
Administrator to demonstrate attainment with
the 24-hr NAAQS.
24-hr NAAOS - Nonattainment Situation
If (1) the total number of observed
exceedances measured by a reference sampler
results in an estimated number of exceedances
to be greater than one, or (2) .one or more
exceedances are observed by a reference
sampler and the total number of observed
exceedances measured by reference and
nonreference samplers results in an estimated
number of exceedances to be greater than one
(subject to the rounding conventions and
adjustments specified in Appendix K), then
the State • should acknowledge that a
nonattainment problem exists and take
appropriate action.
24-hr NAAQS - Indeterminate Situation
If the total number of observed exceedances
results in an estimated number less than or
equal to one, but the available data is
insufficient to demonstrate attainment as
judged under Appendix K, the State or local
monitoring agency must continue PM10 sampling
until attainment or nonattainment of the
NAAQS can be established.
COMPARISONS WITH THE ANNUAL NAAQS
When insufficient reference data are available to
estimate the PM*, expected annual mean according to Appendix
K, then nonref erence data can be used to supplement and
corroborate data produced by the reference samplers. In
order to facilitate this discussion, the following
definitions are introduced:
(1) x. and XM represent the annual means computed from data
produced by reference and nonreference samplers,
respectively.
(2) x'M represents the nonreference mean adjusted for the
effect of the gray zone, as follows:
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x'« = 1.2 x,™, if nonreference data is Wedding3,
= 0.8 x,,, if nonreference data is Sierra
Anderson1,
= x«, if nonreference data is produced by certain
dichotomous samplers specified in footnote 1.
(3) x and x' represent the range of estimated annual means
resulting from a combination of data produced by
reference and nonreference samplers and the effects of
the gray zones:
x •» p * XM + (1-p) * x., and
x'- p * x'« + (1-p) * x.,
where p is the relative weight placed on the
nonreference data (e.g. p • 1/3 when 1 year of
nonreference and 2 years of reference data are
available).
Annual NAAOS - Attainment Situation
If x, is less than or equal to 50 ug/m1 and both
x and x' are also less than or equal to 50 ug/m5
(subject to the rounding conventions and
adjustments specified in Appendix K), then the
nonreference data have corroborated that the
expected annual mean is less than the level of
the NAAQS and the State can solicit approval by
the appropriate Regional Administrator to
demonstrate attainment with the NAAQS.
Annual NAAQS — Nonattainment Situation
If x. is greater than 50 ug/m1 and both x and x'
are also greater than that concentration level
(subject to the rounding conventions and
adjustments specified in Appendix K), then the
State should acknowledge that a nonattainment
problem exists and take appropriate action.
Annual NAAQS - Indeterminate Situation
If (1) x* is less than or equal to 50 ug/m1,
and x or xf is greater than 50 ug/m1, or (2)
x, is greater than 50 ug/m1, and x or x' is
less than or equal to 50 ug/m1, then the
'GMW9000 or any comparable Wedding designed high volume PM10
sampler without a cleaning port.
'SA321A
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status with respect to the annual standard is
indeterminate and the State or local
monitoring agency must continue PM10 sampling
until attainment or nonattainment of the
NAAQS can be established.
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ATTACHMENT B
REVISED POLICY FOR INTERPRETATION OF PM10 MEASUREMENT DATA
DATA COLLECTION TIME PERIOD
Prior to
Aug. 1, 1987
(effective
date of
promulgation)
Aug 1, 1987
to
July 31, 1988
From
Aug. 1, 1988
PM,. Sampler:
Reference
Samplers
Face Value
Face Value
Face Value
Unapproved
Samplers1
SA & Wedding
(older)
Dichots
Gray Zone*
Face Value
Gray Zone
Face Value
Not to be
Used*
Not to be
Used1
1 Data produced by unapproved samplers may only be used to
support and corroborate data produced by reference
samplers.
* A zone of uncertainty within which PNIO data are used with
less authority, as discussed in Attachment A; Gray zone
limits were defined in the PM,. SIP Development Guideline.
1 For attainment/nonattainment and design values only;
Regional Administrator approval for other SIP purposes
(40 CFR 58.l4(b)).
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Attachment C
ISSUE PAPER:
TREATMENT OF UNCERTAINTY IN AMBIENT PM10 MEASUREMENTS
Prepared by
PM10 MEASUREMENT WORKING GROUP:
N. H. Frank (Co-Chair)
T. G. Pace
N. J. Berg, Jr.
Office of A1r Quality Planning and Standards
L. J. Purdue (Co-Cha1r)
F. F. McElroy
K. A. Rehroe
A. J. Hoffman
0. M. Holland
R. C. Rhodes
Environmental Monitoring Systems Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
September 1988
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ISSUE PAPER:
TREATMENT OF UNCERTAINTY IN AMBIENT PM10 MEASUREMENTS
September 1988
ISSUE: Field comparisons of various different types of
samplers generally indicate consistent measurement
differences or "relative biases" between or among the
different samplers, suggesting uncertainty in the PMio
measurements. The-magnitude of this uncertainty, which
appears to be somewhat greater than corresponding un-
certainties associated with gaseous pollutants, raises
questions and concerns about the utilization of PH^Q
data in the determination of attainment of the NAAQS
and in the development of SIPs.
INTRODUCTION
Background on
Measurement Method
The nature of part1culate matter In the atmosphere 1s very complex.
Airborne particles exist in a wide variety of sizes, shapes, density, surface
characteristics, chemical composition and other features. Various equilibria
may exist between the volatile, semi-volatile, and non-volatile components of
the atmospheric particle mixture. Consequently, measurement of particulate
matter in the ambient air, especially in the 0 to 10 micrometer size range
(pMlu)» 1s difficult. Various mechanical techniques for discrimination and
collection of-particles In the PMio size range are likely to perform somewhat
differently, depending on the particular characteristics of the particles in
the atmosphere being sampled. Further, PM^Q measurements will tend to. be
somewhat characteristic of the type of sampler used, and measurements from
different types of samplers are likely to be characteristically discrepant, to
some extent. Finally, since no absolute concentration standard for particular
matter exists, particulate matter samplers cannot be calibrated against known
reference Materials, as 1s done 1n the measurement of single-compound gaseous
pollutants such as SO?, NUg, CO and 03. Accordingly, PMiQ measurement methods
can provide only estimates of the "true" PM^g concentrations.
The recently promulgated Federal Reference Method (FRM) for PNju (40 CFR
Part SO, Appendix J) specifies an integrated 24-hour PMm measurement based
on discrimination of particles in the PM^j size range by inertia! separation,
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followed by conventional filtration of a measured volume of sampled air and
determination of the net weight gain of the filter. Under these new FRM
requirements and associated requirements in 4U CFK Part 53, PM^o samplers are
specified by performance (i.e., wind tunnel tests for sampling effectiveness
and bu percent cutpoint and field tests for precision and flow rate stability)
rather than by sampler design specifications. This approach was taken to
provide greater engineering flexibility to allow for the use of various
existing sampler designs and to encourage continuing improvements and inno-
vative new sampler designs. But in providing this design flexibility, the
performance specification approach Inherently allows for some measurement
differences between approved PMiQ samplers due to the necessary tolerances in
the performance specifications (e.g., 05 U cut-point: 10+0.5 micrometers,
expected mass: +10%). It was anticipated that samplers which meet the
performance requirements would provide PMio measurements within a 10 percent
range at the majority of the required sampler locations.
Observed Measurement Differences Among PMio Samplers
Ambient PMio concentration data have been collected with a variety of
samplers over the last several years. These Include high-volume samplers
currently designated as PMio reference methods, earlier commercially avail-
able versions or prototypes of reference method samplers, and low volume
dlchotomous samplers. The PMio sampler type most commonly used has been the
Sierra-Andersen (SA) high volume sampler, which was procured and distributed
to many state and local monitoring agencies by EPA. There also have been a
substantial number of Wedding & Associates (Wedding) high-volume PMio samplers
In use, as well as a limited number of low -volume dlchotomous (dlchot) samplers
with PMio Inlets manufactured by both SA and Wedding.
Significant characteristic differences between PMio measurements from
earlier versions of the SA and Wedding samplers were Identified during several
field studies designed to evaluate sampler performance. Generally, SA sam-
plers produced higher concentration measurements than Wedding samplers. These
observed differences Indicated uncertainty In the PMio measurements. But the
characteristic differences between these dissimilar sampler types were signifi-
cant and separate from the random uncertainty that Is associated with the
overall measurement process. These differences are referred to as "relative
biases" or "biases", because they can be quantified only on a relative basis,
since no absolute PM reference standard exists.
Sampler manufacturers have Incorporated various Improvements Into their
respective samplers, resulting In the versions that are currently 1n use and
have been recently designated as reference methods for PMio under the provi-
sions of 40-CFR Part S3. Although the Improvements substantially reduced -the
relative biases observed between the SA and Wedding samplers, subsequent
field studies have Indicated that residual biases still exist between these
reference method samplers. The biases are variable and site-dependent to some
extent. Variations may also be related to seasonal changes, weather, or
other local variables. Average differences between CPA-deslgnated, collocated
SA and Wedding samplers varied between 5 and IS percent at four locations.
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Differences between earlier SA and Wedding sampler versions were somewhat
greater. Since PM^g reference method samplers have been part of State and
local air monitoring stations since early 1988, the PM^g data currently
being collected should be less uncertain than data collected with earlier
versions. EPA is continuing to work with sampler manufacturers to try to
identify the causes of the biases and to further reduce them.
Current Interpretation and Use of PMio Measurement Data
data is essential in the determination of attainment/non-attainment
status and In the development of SIPs. At the time of the promulgation of the
PMio standards, available PMio data was analyzed together with historical TSP
data to estimate current PMio ?ir quality status and to group areas for SIP
development purposes, uncertainty was recognized in existing PMig measurements,
and "gray" uncertainty zones were utilized to Interpret these data to predict
the probability of attainment with the standards. A gray uncertainty zone
of 0 to +20 percent was placed around the level of the standard for data
produced by the SA sampler, and a zone of 0 to -20 percent was employed for
data from Wedding samplers. Using existing PM}Q monitoring data that was
outside of these gray zones, areas could be categorized as either likely to
be in non-attainment (Group I), or likely to be 1n attainment (Group III).
When PH jo data fell Into the applicable gray zone, the area was categorized
as too close to call (Group II) and additional time was given to collect more
PW ID data and ascertain unequlvocable attainment status.
The gray zones were derived from the results of a field study conducted
1n Phoenix, Arizona, which Indicated that differences between SA and Wedding
samplers of plus or minus 20 percent were possible. At that time, EPA belief
that the Phoenix test site was atypical and that measurements from existing ^
samplers would be in better agreement in more typical sampling sites. Therefore,
EPA's guidance for subsequent SIP development stated that "data collected
with all Instruments will be taken at face value when demonstrating attainment
or non -attainment with the standards." However, to allow for the possibility
that potential sampler bias could exist In specific locations, the guidance
also stated that an appropriate adjustment would be permitted for attainment
demonstrations. 1f Influence by coarse particles could be demonstrated.
Since a determination of attainment with the PMio standards generally.
requires at least 3 years of monitoring data, existing guidance allows that
both newer reference method data as well as older unapproved method data
may be utilized for these assessments. In light of the results from
recent field studies of PMio samplers, questions and concerns continue to
be raised as to the treatment of the uncertainties in PMio data from botn
reference Method samplers and earlier versions In the application of the
data to the attainment and SIP determination processes. Accordingly,
this paper addresses this issue, and recommends a policy for interpretation
of PMio data to facilitate these processes.
Options
A joint OAQPS/EMSL committee has evaluated this issue and identified
three cases where the treatment of uncertainties of PMio monitoring data
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APPENDIX 3
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should be considered. The first and most important case is the treatment of
PMiu data obtained currently or previously with EPA-designated reference
method samplers. This case primarily addresses many of the data collected
during the past year and all future data collected for determining attainment
status with the PMio standards. The second case is the treatment of data
collected over the last two or three years with earlier, unapproved samplers
(non-EPA-designated). This case addresses data collected with earlier
unapproved versions of the SA and Wedding PMio samplers and applies only to
data collected prior to August 1, 1988. (under the provisions of 40 CFR Part
58, approved PMiQ samplers must be operational for attainment purposes after
this date.) Finally, the third case addresses the special situation where
two or more samplers are collocated and produce concurrent PMio monitoring
data.
The committee Identified three possible optional approaches for contending
with the uncertainty In the PMio data with respect to the attainment and SIP
determinations for cases I and. II Identified above. Two of the options are
further divided Into two subopt'lons. The options are:
1. Use all PM measurement data at face value.
2. Adjust PMio measurement data with adjustment factors developed for
each type of sampler:
A. Universal factors used nationwide.
B. Site-specific factors.
3. Use PMio measurement data selectively:
A. By defining a particular specific sampler as "correct" or
as the "reference sampler".
B. By using a "gray zone" 1n Interpreting and using PMio data
from the various PMm samplers.
These optons are addressed Individual ly» highlighting the positive and
negative aspects of each with respect to cases I and II. Since all of the
optional approaches have significant drawbacks or disadvantages, selection of
the best option for each category of data Involves careful evaluation and
weighing of the tradeoffs between the various advantages and disadvantages.
The nature Jff'case III 1s somewhat different from cases I and II and four
special alflHHVtlves are discussed for this case.
I. TREATMGft OF MIQ DATA OBTAINED WITH E PA-DESIGNATED REFERENCE METHOD
SAMPLERS
OPTION 1: Use all PM measurement data at face value.
In this approach, all validated PMio concentration data from any approved
reference (or equivalent) sampler are reported and used at face value with full
authority, just as data for other criteria pollutants are reported and used.
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No special adjustments are made or special treatments are utilized. All
pollutant measurements contain uncertainty, and this uncertainty is accommodated
in the policies governing the appplication of the measurement data. Difference^
between PM^y data from dissimilar samplers would be viewed as a component of tW
overall uncertainty associated with PM^Q monitoring data and accommodated in the
same way as for the other pollutants.
Advantages
1. This approach Is entirely consistent with the established data reporting
and utilization mechanism established for the other criteria pollutants.
No changes or deviations are required for PMnj. There will be no delay
before the data are available for use, and no additional effort or
resources are needed to process or Interpret the data.
2. The approach Implies adequacy of the data and avoids undermining Its
credibility by not drawing attention to problems or questions of data
quality and applicability.'
3. This approach supports the FRM concept of functional specifications for
PM}u samplers and reaffirms EPA's confidence In and commitment to that
concept. Further, it represents the ultimate Ideal goal as the sampler
manufacturers continue to Improve the samplers and reduce or eliminate
significant bias between different sampler models.
4. The approach Is reasonable 1n the sense that all criteria pollutant
measurements contain uncertainty to some extent, and accepting a higher
level of uncertainty for partlculate matter measurements than for gaseou
pollutant measurements 1s not Inappropriate. If a substantial bias e
between two samplers. It Is reasonable to assume that the "true" concen-
tration lies between the two estimates. Therefore a bias of as high as
15 to 20% may represent an actual error of only 5 to 10% or less. That
level of uncertainty 1s not unacceptable 1n the context of other uncer-
tainties 1n the air quality assessment process, such as locating a sampler
at a point of maximum pollutant Impact, losses of semi-volatile particles
from the filter, other operational errors Inherent In any particle collec-
tion method, and the recognized uncertainty associated with the use of
dispersion models.
5. The approach 1s defensible because the advantages listed above are reason-
ably clear, readily supportable, and can be weighted heavily In comparison
to the disadvantages and to the relative advantages of other approaches.
\
Disadvantages
1. The uncertainty In PM^j measurements appears to Include a relative bias
reflected by a consistent difference between measurements produced by
different sampler types. The magnitude of this uncertainty Is apparently
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APPENDIX 3
5 Page 59 of 86
larger than uncertainties associated with other criteria pollutants.
Perhaps more significant, the PMiu uncertainties may exceed a level of
10%, which is widely perceived as an upper limit of acceptability for data
uncertainty. If the higher levels of uncertainty in the PMjy data can be
justified as acceptable (see advantage 14), this may not represent a
profound problem.
2. To the extent that relative biases exist among various types of samplers,
monitoring agencies and certainly industry may strive to use the lowest-
reading sampler available. Correspondingly* sampler manufacturers may try
to modify or redesign their samplers to provide relatively lower PHju meas-
urements while still meeting the EPA sampler performance test specifications.
3. This approach does not deal directly with whatever bias problem May exist
and may be perceived as failure to take action to address the problem. It
also places a burden on the EPA to continue to perform field studies to
ensure that approved samplers are operating according to expectations and
that biases between approved samplers are Identified and addressed.
4. Where bias exists between two types of PMio samplers, replacing one
sampler with another at a particular site may present a problem In trends
analysis at the site. Similarly, the further Improvements and reduction
of biases between samplers that 1s expected to occur .though 1t may result
in only small changes, could Interfere with trends analysis. Finally,
although current guidance for collocation sampling for precision assess-
ment strongly recommends use of similar-type samplers, monitoring agencies
that collocate dissimilar PM^Q sampler types (for whatever reason) could
be faced with dealing with characteristically discrepant measurements
from the two samplers. See Case III (Treatment of PMio data obtained
concurrently with collocated samplers) for further discussion of this
situation.
OPTION 2: Adjust PN^ measurements with adjustment factors developed for
each type of sampler on either (A) a universal, nationwide basis
or (B) a site-specific basis.
Under this approach all validated PMio data collected with approved
samplers would be adjusted in an attempt to reduce or eliminate the observed
biases between the different sampler types. Relative bias would have to be
quantified and apportioned to the various samplers In some logical and equit-
able fashion to establish the various adjustment factors. This process could
be based on a>l available comparative PMio sampler data to establish universal
factors for nation-wide application. However, since sampler biases are likely
to be site-dependent, factors developed on a site-specific basis would likely
be more accurate and more credible.
An adjustment factor can be viewed as simply a means of fine-tuning the
accuracy of a PHiu sampler, which lacks any physical means for doing so. As
such, the adjustment .serves the same purpose as the span control on a gaseous
pollutant analyzer. The only difference 1s that since no absolute concentration
standards exist for MIU» the factor cannot be determined In an absolute sense
and therefore must necessarily be established on a relative basis.
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Advantages
1. This approach addresses the bias problem actively and directly,
presumably reducing the biases (and hence the uncertainty in the
data) to levels comparable to those of other criteria pollutants.
2. Once the data corrections are accomplished, the data may be stored,
retrieved and used via the same mechanisms used for other pollutants,
with the same authority and with no further special considerations.
Data credibility would be restored and with the use.of a universal
factor (developed by EPA), no additional burdens on state or local
reporting agencies would be Imposed.
3. Reductions of bias among various samplers will greatly reduce the tendency
for Industry and monitoring agencies to select or switch samplers to obtain
the lowest PM^ measurements. Accordingly, manufacturers will be under
much less pressure to arbitrarily modify or redesign samplers for lower
PMjn measurements to compete successfully In the sampler marketplace.
Equitable allocation of the relative adjustment factors will not favor any
one manufacturer.
4. Use of site-specific adjustment factors could more effectively reduce
observed biases at Individual sites and therefore mitigate site-to-
site variations in biases that would not be addressed with universal
sampler adjustment factors applied nationwide.
5. If sampler biases are effectively reduced with appropriate adjustment
factors, there could be less Incentive for manufacturers to redesign already
approved samplers. This would Introduce stability Into the collection a^P
reporting of PM^j measurements.
Disadvantages
1. Even though the adjustment factors need not be established on an absolute
basis, quantitative determination of the relative factors 1s difficult
because of .the variations observed at different sites and under different
conditions. Existing test data are not sufficient. Additional field testing
of samplers to obtain more complete relative bias data 1s very expensive,
and the site-dependence of the relative biases Is not well enough understood
to accurately categorize various sites to Insure adequate representation of
the test sites. Other variables such as sampler Maintenance, seasonal
variations* weather, and other local variables further complicate the
testing^ Also, weather and other seasonal variations raise the question of
whether the site-specific adjustment should be season specific.
2. Newly-approved samplers would definitely have to be tested for relative
bias with respect to previously approved samplers, since there would be no
existing test Information. Since bias adjustments would be made on a
relative basis among approved samplers, rather than against a known
standard, data from the new sampler (or any new test data that become
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8
available) might necessitate new adjustment factors. The resulting
changes would interfere to some extent with trends analyses and
previous attainment determinations.
3. Establishment of relative adjustment factors would almost certainly be
viewed negatively by the sampler manufacturers, particularly manufacturers
of samplers characteristically producing the lowest PM^o measurements. Any
manufacturer could claim its own sampler as most nearly "correct" and thus
object to adjustments of Its sampler's data to accommodate claimed "error"
in the PMjo data from its competitors' samplers.
4. The approach Mould be subject to criticism and somewhat difficult to defend.
Since the adjustment factors would be based on relative bias among the
samplers and not on an absolute basis, the adjustment factors would have to
be supported with arguments based on logic and expediency rather than on
absolute scientific accuracy.
5. Adjustments to PM^g data c'ould raise difficulties or undermine the confidence
in the performance or comparative tests for reference and equivalent methods,
because such factors would be relative rather than absolute. Any subsequent
change in the correction factor associated with the reference method used
in an equivalent method comparative test could bring the validity of the
equivalent method designation into question.
6. If sampler biases are effectively reduced with appropriate adjustment
factors,, there could be much less incentive for further modification or
redesign of already approved samplers to further reduce relative biases,
which should be the ultimate goal.
7. Because of site-to-site variations in the biases, application of a
universal adjustment factor could actually be counter productive In
some specific cases.
8. Implementation of site-specific adjustment factors appears to be
impractical. Who would be responsible to develop the Individual factors?
Who would keep track of so many factors? Would Individual factors be
developed for each monitoring site or could factors be developed for all
sites in a larger monitoring area? What basis could be used to define such
a larger area? It would seen to be prohibitively costly to try to obtain
test data at each Individual site. How would data from a particular site
be treated before the appropriate adjustment factor was established?
OPTION 3A: Use PMiQ measurement data selectively by defining a particular
specific sampler as "correct" or as the "reference sampler."
This option would select one type of PMiu sampler as the "best" or the
one that produces measurements "closest to the true PMio" concentration. The
selected sampler would be designated as the "reference* sampler, and all PMio
data collected with any other type of sampler presumably would be adjusted,
to the best extent possible, to eliminate bias with respect to the reference
sampler.
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Advantages
1. The advantages for this option are essentially the same as those listed
for Option 2 (adjustment of PMiy measurements with sampler-specific
factors). In addition, the option would be simple in concept and
straightforward to implement.
Disadvantages
1. This approach has the serious disadvantage that it is in conflict with the
performance specification concept promulgated in 40 CFR Parts 50 (Appendix
J) and 53. Thus, adoption of this approach would appear to require extensive
revision and repromulgation of those regulations. Changing the regulations
would result in extensive disruption of current monitoring, substantial
delay before revised regulations are in place, and the need for an Interim
policy for treatment of PM^j data collected prior to implementation of the
revised regulation.
2. There is little basis for selection of the "best" sampler for reference
method status, given the present state of the art of PM^o monitoring and
the lack of absolute PMio standards. Thus, the selection would be largely
arbitrary. Manufacturers of nonselected samplers would surely object very
strongly, and the approach will be difficult to support on a scientific basis.
3. This option would be equivalent to the design approach concept for specifying i
PMiu samplers that was rejected during the development of the current PMjo
reference method because of the need for technical flexibility in sampler
types and design approaches.
OPTIUN 3B: Use PM^o measurement data selectively by using a "gray zone" In
interpreting and using PM^j data from the various PM}o samplers.
Under this approach, data would be reported and stored at face value.
However, during use of the data, a "zone of uncertainty" (gray zone) would be
associated with the PM}0 measurements, and the true measurement would essentially
be viewed as an interval of possible values. For the critical comparisons with
the level of the PMiu standards, the zone would be defined around the level of
the standard, as was previously done*for SIP area groupings. The magnitude of
the zone would reflect the estimated uncertainty for the sampler used, and the
zone would be nonsymetrlcal or offset (+01 to -16%, for example), depending on
the magnitude of the relative bias among PMm.samplers. PM^o concentrations
within the girvy zone would be considered less authoritatively than concentration
outside the gray zone.
Advantages
1. No changes are needed to PM^jdata collected either previously or currently
with reference method samplers.
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10
2. Less attention would be drawn to problems of data quality or credibility
than the correction factors of Option 2.
3. The approach acknowledges the bias problem and provides a mechanism to
consider the effects of relative biases between samplers during data
interpretation. The approach was used successfully in the previous area
grouping process to establish initial PM^j sampling requirements.
4. This approach is consistent with the FRM concept of functional
specifications for PMio samplers.
5. Consideration of the effects of relative bias among various samplers will
reduce the tendency for Industry and monitoring agencies to select or
switch samplers to obtain the lowest PM}o measurements. Accordingly,
manufacturers will be under less pressure to arbitrarily modify or
redesign samplers for lower PM}o measurements to compete successfully In
the sampler marketplace.
Disadvantages
1. A separate and substantially different interpretation process than the
process currently used with reference or equivalent data for the other
criteria pollutants would be required. This will result 1n possible
confusion among data users 1n knowing exactly what the special treatment
process 1s and considerable additional effort In learning and carrying
out the different process for PMio data.
2. Less stringent enforcement of PHjo concentrations that fall within the
gray zone may be regarded as relaxation of the PMio standards and prove
to be embarasslng to EPA.
3. This approach may delay the attainment determination process. It could
require additional time and or data to determine attainment and shorten
the available time for control strategy Implementation.
4. The width and offset parameters for the gray zones must be established
for each sampler. Quantitative determination of these parameters must be
made on a relative basis and will be difficult because of the variations
In biases observed at different sites and under different conditions.
Existing test data 1s not sufficient. Additional field testing of samplers
to obtain more complete relative bias data Is very expensive, and the
site-dependence of the relative biases Is not well enough understood to
accurately categorize various sites to Insure adequate representation of
the test sites. Other variables such as sampler maintenance, seasonal
variations, weather, and other local variables further complicate the
testing.
b. Newly -approved samplers would have to be tested for relative bias with
respect to previously approved samplers, since there would be no existing
test information to use as a basis to establish the gray zones. Moreover,
the bias data from the new sampler (or any new bias test data that becomes
available) might necessitate changes to other gray zone parameters.
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11
6. Establishment of the gray zones will tend to reduce the credibility of the
PMu data, and therefore enforcement may be more difficult. The approach
would be subject to criticism because the gray zones would be based on
relative bias among the samplers and not on an absolute, scientific basis.
Recommendation
Upon weighing and evaluating the various advantages and disadvantages
of the three optional approaches, we believe that option 1, use of all PM^Q
data at face value, is clearly the best course of action. The approach fully
supports the FRM functional specification concept that provides the technical
flexibility needed for competitive sampler innovation, and it is fully. consis-
tent with the interpretation of data for the other criteria pollutants. It
is a reasonable approach that implies data credibility. Further, it encourages
and anticipates further improvements In the currently designated reference
method samplers and any new candidate reference or equivalent methods. Signifi-
cant improvements have been made to the two designated samplers, and additional
improvements are anticipated, Which should result in further reductions in the
relative bias between these samplers. Manufacturers of new samplers should
benefit from the experience with these Initial samplers and should be better
able to address or avoid the problems encountered 1n their use.
When the performance -based approach for specifying PN^y samplers was
selected, the potential for bias between approved samplers due to effects not
directly addressed by the wind tunnel performance tests (e.g., effects from
soiling during field use) was recognized. It was anticipated that the magnitude
of these effects would be relatively small, and when problems were Identified^
that the manufacturers would take proper corrective actions. Although the
relative bias between the first two designated reference method samplers is
larger than anticipated, the manufacturers are working on correcting the
problems. We believe that It would be premature at this point in tine to pre-
sume that these problems are not solvable and that one of the other options for
data treatment should be pursued. .-• -.-
These are compelling arguments in support of this approach. The dis-
advantages, while significant, appear to be substantially less serious than
those listed for the other approaches and can be realistically accommodated.
Accordingly, this option 1s recommended and, we believe, represents a valid,
workable, and defensible approach to treatment of the observed relative biases
among various PM].u samplers.
Given this recommendation, we recognize, nonetheless, that some variability
in PMiu measurements may be due to Instrument differences. Therefore, we
encourage «on1tor1ng agencies to try to assure historical continuity 1n PMm
measurements by using comparable reference monitoring methods (e.g., same manu-
facturer) at the same location over time. Furthermore, when multiple Instrument
are used at the same location to perform every-other-day or everyday sampling,
comparable methods should also be used.
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II. TREATMENT OF PM DATA OBTAINED WITH UNAPPROVEU SAMPLERS
There have been several types of unapproved PM^j samplers which have pro-
duced PMjQ data over the last few years. The. most prevalent data producers,
by far, were older versions of currently approved high-volume samplers.
Although used to a much lesser extent, dichotomous samplers have, nevertheless,
produced a significant amount of PMjQ data. Dichotomous sampler inlets have
been changed or modified very little since their introduction, and comparative
tests show generally consistent results that agree well with currently designated
high-volume PM^Q samplers. Designation of the first dtchotomous sampler as
reference method 1s anticipated soon. For these reasons, dichotomous data
requires no special treatment and should be used at face value. Accordingly,
the following discussion will focus only on alternative treatments of data
produced by the earlier versions of the currently designated high volume
samplers manufactured by Sierra-Andersen and Wedding & Associates, Inc.
OPTION 1: Use PM^g measurement data from unapproved methods at face value.
In this approach, all validated PM^g concentration data from any unapproved
PMjQ sampler are reported and used at face value with same authority as reference
or equivalent method data. No special adjustments are made or special treatments
are utilized.
Advantages
1. This approach is identical to the current EPA policy regarding the use of
measurements from unapproved PMjo methods, even If these measurements were
affected by a gray zone in the area grouping process. This policy is based
on the judgement that the field study situation In Phoenix was atypical and
that sampler agreement would be better in most areas without the pervasive
large particles characteristic of the Phoenix test site.
2. This approach permits an area to make full use of PMjo data collected prior
to the NAAQS promulgation in order to compile the 3 years of data generally
needed to assess attainment with the standards.
3. This approach Is simple to Implement and requires no change in current
policy.
Disadvantages
1. This approach Ignores the reported bias between the earlier PMjn sampler
version*. Recent field studies have shown that large biases exist in more
locations than previously suspected.
2. This approach could cause an erroneous attainment or non -attainment
determination.
3. This approach is. inconsistent with data usage for other NAAQS pollutants
in which data from non-reference or non-equivalent data is not used.
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4. With the existing EPA guidance regarding the face-value use of data pro-
duced by unapproved samplers, monitoring agencies may want to demonstrate
that adjustment factors are appropriate. This policy places a burden on
the reporting agencies to demonstrate that the affected data were biased.
OPTION 2: Adjust PMiQ measurements from unapproved methods with factors
developed for each type of sampler on either (A) a universal,
nationwide basis or (B) a site-specific basis.
Under this approach, all validated PMnj data collected with unapproved
samplers would be adjusted in an attempt to reduce or eliminate the apparent
biases between the different PMiQ samplers.
Advantages
1. As indicated for the use of data produced by approved reference method
samplers, this approach addresses the bias problem directly, and the
adjusted data may be used via the same mechanisms used for other
pollutants. In this case, adjustment factors may have to be established
based on comparative test data from approved sampler versions if test
data for the unapproved version is unavailable.
2. Use of site-specific adjustment factors Mould more effectively mitigate
site-to-site variations in biases that would not be addressed with
universal sampler adjustment factors applied nationwide.
3. The current EPA policy tentatively allows adjustment of older data on a
local basis if bias can be demonstrated. This could involve developmen^
of factors derived from data obtained from collocated reference method
and unapproved samplers.
Disadvantages
1. The development and application of factors for data obtained with
unapproved methods have the same disadvantages as those for data obtained
with approved samplers.
2. If factors were derived from collocated sampling with approved and un-
approved samplers, the factors may be developed with data collected
during one time period and applied to data collected during a different
time period. This would Involve making potentially questionable
assumptions regarding similarities In sampling conditions (e.g., PM}Q
emissions, meteorology, and particle size distribution).
OPTION 3A: Use PMiy measurement data selectively by defining a particular
specific sampler as "correct" or as the "reference sampler".
For completeness of the discussion. Option 3A is also included for the
treatment of un approved sampler data. With this approach, however, the
selected sampler must be one of the reference samplers; therefore, data
produced by any unapproved PM}y sampler would not be used for air quality
assessment.
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Advantages
1. If data from unapproved samplers were considered invalid, this approach
would be entirely consistent with data usage for other criteria pollutants
2. This approach is simple to implement.
Disadvantages
1. Although many measurements produced by unapproved PM}Q samplers In some
sampling situations are uncertain or may be potentially biased, these
measurements are not totally useless. When measured PM}o concentrations
produced by a sampler that is apparently biased lower than other samplers
are greater than the level of the standard, there 1s a high probability
that an exceedance has occurred. Similarly, when measurements by a
sampler that is apparently biased higher than other samplers are less
than the level of the standard, then there 1s a high probability that an
exceedance has not occurred. These data, therefore, can play a useful
role in demonstrating that a location 1s clearly In attainment or
n on -attainment.
2. Selection of measurements from only one PHjo sampler Is not practical
to consider for the same reasons discussed for the reference samplers.
3. Although application for approval of certain PMio samplers has not yet
been formally submitted to EPA, these samplers are unofficially recognized
as producing relatively unbiased PH^g measurements. Such Instruments
Include dichotomous samplers .
OPTION 38: Use PMjQ measurements selectively by using a "gray zone" in
interpreting and using PM^j data from unapproved PM^Q samplers.
With this approach, data would be reported and stored at face value.
However, during use of the data, a "zone of uncertainty" (gray zone) would be
associated with the PM^Q measurements, as discussed under option 3B for
measurements from approved samplers. The same zones used for the area grouping
process (0 to +20 percent for the SA and 0 to -20 percent for the Wedding
samplers) would be utilized for attainment determination and SIP development.
Advantages
1. The advantages discussed In Section I, Option 3B for the reference method
sampler* are also applicable to the unapproved samplers.
2. The use of the gray zone option does not require any direct adjustments to
the monitoring data, but permits their selective use for attainment/
non -attainment determinations. The data may be helpful to support and
corroborate a determination of attainment or non-attainment, or to establish
that the status is indeterminate, in which case additional data would
be required.
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3. The use of the gray zone permits the use of nonreference data to support
the determination of attainment or nonattainment for many areas (i.e.,
whose critical data is not close to the levels of the PM^ standards)
while recognizing relative biases that may exist in those data.
Disadvantages
1. Gray zone treatment for older data is more likely to cause an area to
have an indeterminate attainment status. This could potentially delay the
SIP process for some areas with affected data. The. delay would be due to
extending the time period necessary to collect additional data for
unequivocal attainment/nonattainment determination. However, this would
primarily involve those areas which are borderline attainment/nonattainment.
2. Application of the gray zone approach to data collected with unapproved
samplers after the time reference samplers were generally available could
permit an additional delay in attainment/nonattainment determination for
Group II areas and subsequent SIP development.
Recommendation
Vie believe that option 38, use of data selectively by using a gray
zone Interpretation to support and corroborate data produced by reference
samplers, 1s clearly the best course of action for measurements from
unapproved SA and Wedding samplers. This approach recognizes the potential
uncertainty in older PM^g measurements and reinstates a precedential policy
that has been used successfully and with which people are already familiar.
The same zones of plus or minus 20 percent would be utilized. Specifically,
this translates to unapproved SA concentration ranges of 50 to 60 ug/m3
for the annual standard and 150 to 180 ug/m3 for the 24-hour standard.
Unapproved Wedding sampler ranges are 40 to 50 ug/m3 and 120 to 150
ug/m3, respectively. Data within these ranges would be used with less
authority than data outside these ranges. Alterations to this general
rule could be considered on a case-by-case basis and must be discussed with
OAQPS.
We recommend that the gray-zone* policy only be applied to data produced by
unapproved SA or Wedding samplers before August 1, 1988. This date 1s one
year from the effective date of the PMio regulations. After this date, the
use of data produced by unapproved samplers Is not permitted for determinations
of attainnent/nonattainment and calculation of design values (40 CFR Part
58.14(a)). With Regional Administrator approval, however, these data may be
used for other SIP purposes (40 CFR Part 58.14(b)). We also note that older
PMjQ data from unapproved SA or Wedding samplers may no longer be needed for
current air quality assessment when 3 years of data from approved samplers
are available.
An effect of reinstating the gray zone approach may be a temporary delay
in the immediate determination of attainment or nonattainment for some
areas with older data from unapproved samplers in the gray zone (i.e., close
to the standard). Control agencies with data affected by gray zones must
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recognize that these measurements represent potential exceedances and,
therefore, they must anticipate the possibility of future control strategy
development. Additional SIP development guidance may be needed for this
situation (e.g., requirement of accelerated sampling, dispersion modeling,
etc.).
Finally, we note that data produced by dichotomous samplers should be
interpreted the same as data produced by EPA-designated samplers (i.e. at
face value) but only to support measurements produced with reference samplers.
However, as long as the dichot is not approved as a reference sampler,
only data collected before August 1, 1988, may be used to support attainment
assessment and calculation of design values. Nonetheless, these data may
continue to be used for control strategy development and other SIP purposes
with RA approval.
HI. TREATMENT OF PM10 DATA OBTAINED CONCURRENTLY WITH COLLOCATED SAMPLERS
samplers may be collocated to produce concurrent measurement data
at the same site for quality assurance, attainment assessment or other SIP
purposes. The samplers may be operated by a single monitoring agency or by
separate monitoring agencies (governmental, environmental or Industry).
The PMiu regulations specify different sampling and data requirements
according to the Intended application of the data. For attainment
assessment and calculation of design values, monitors must meet all Part 58
requirements for SLAMS as well as minimum data requirements specified 1n
Appendix K to 40 CFR Part 50. For quality assurance (QA) and other SIP
purposes, monitors and data must only meet less stringent requirements.
Accordingly, where two or more PM^Q samplers are collocated and
operated simultaneously, treatment of the PN^Q data from these samplers
depends on the Intended purpose of the measurement data and compliance
with the appropriate regulatory requirement. In all cases, measurements
from an approved sampler take precedence over measurements from unapproved
samplers. If two (or more) approved samplers are collocated and operated
concurrently by a single monitoring agency for any purpose, one sampler
must be designated, at random, a priori as the primary sampler whose
samples will be used to report air quality for the site. All other
samplers are designated as duplicate or special purpose monitors (SPMs).
This 1s established data reporting procedure and 1s described 1n Section
3.3 of Appendix A to CFR Part 58. In general, data from duplicate samplers
are not used for attainment assessment; only the primary sampler's data
are used. However, according to Appendix K to CFR Part 50, data from
such duplicate Monitors mist also be used for assessing attainment 1f the
appropriate SLAMS requirements (Including sampling frequency) are met.
Furthermore, separate monitoring agencies (governmental, environmental or
industry) may be operating one or more approved collocated samplers which
also meet all of the SLAMS requirements and whose data also meet the
appropriate completeness requirements specified In Appendix K. When two
agencies operate samplers at the same location, only one agency's sampler(s)
are part of the SLAMS. The other agency's sampler's represent a special
purpose monitoring site. However, the monitoring regulations specify
that this data must be used as well. The data treatment issue is: how
must this data be used?
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The following discussion applies to the treatment of data for the
purpose of attainment assessment where two or more approved samplers are
collocated and operated concurrently by one or more separate monitoring
agencies and each sampler meets all Part 58 requirements for SLAMS. The
first three options discussed assume that each monitoring agency individually
reports all its data to EPA. The user would perform the selected data
treatment. The fourth option furnishes control of the data to the
responsible monitoring agency, by permiting the agency to select and
report a single set of data to represent the monitoring site. This data
may be produced by a designated sampler or the daily average of
measurements produced by several available reference samplers.
OPTION 1: Measurement data are submitted separately by each monitoring agency.
The data user would average the corresponding measurements from
approved samplers.
When multiple measurements are concurrently produced by two approved
samplers and are reported to EPA, the ambient PMio concentration estimated
for the location would be the average of these measurements. When only one
dally measurement Is available 1n this situation, because other measurements
are missing (e.g., due to sampler malfunction), the reported measurement
would be used without correction. Similarly, the estimate of annual average
PHio for the location would be based on the average of the reference samplers'
average PM}Q concentrations. Dally values and annual reference samplers'
averages would only be considered 1f the data were produced 1n accordance with
the requirements of 40 CFR Part 58 and 40 CFR Part 50, Appendix 1C.
Advantages
1. When multiple measurements are available from approved reference or
equivalent method samplers, each measurement Is an estimate of the true
PMiu concentration. If the errors associated with the measurements are
random, a better estimate of the true value 1s usually produced by
averaging the measurements. PM^Q measurements produced by dissimilar
samplers may be consistently higher or lower than one another, Indicating
that the errors are not totally random. Nevertheless, In the absence
of absolute calibration standards, there Is no Information to Indicate
which measurement 1s the better estimate. Accordingly, averaging
the measurements Is appropriate.
*
Disadvantages
1. Averaging collocated measurements would cause Inconsistency 1n estimation
of dally and annual average PMig concentrations. Some estimates would
be produced by a single measurement from one Instrument type while
others would be the result of different samplers.
2. Averaging of collocated measurements would be a change to the air
quality data usage conventions. Currently, when a single agency operates
multiple samplers at a site, only the primary designated reference
sampler's data is used for making comparisons with the NAAQS. Also,
when multiple agencies operate monitors at the same location, the
highest reported daily or average concentration is used for making
comparisons with the NAAQS.
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APPENDIX 3
18 Page 7 1 of. 86
3. The public "could complain that a NAAQS violation was "averaged away".
OPTIUN 2: Measurement data are submitted separately by each monitoring
agency. The data user would select the highest concentration
measurement produced by collocated samplers.
Advantages
1. When multiple measurements are available, a higher measurement would
provide better protection of public health.
2. Using the higher measurement would help to discourage multiple monitoring
agencies from collocating dissimilar samplers to obtain lower measurements.
3. In general, monitored concentrations underestimate the worst concentration
In an area. This 1s due to the limited size of monitoring networks
and the problem of finding the site of maximum pollutant Impact. Air
quality simulation models usually find higher concentrations due to the
larger grid of receptors. For PMiQ, monitored concentrations may also be
low due to losses of semi-volatile or secondary particles (e.g.,
nitrates). Using the higher of duplicate measurements would tend to
compensate for these effects.
Disadvantages
1. PMio measurements produced by one reference sampler are not necessarily
better than another.
2. If the two samplers were unbiased, relative to each other, then this
approach would Introduce bias In selected peak values. This Is due to
the effect of the Imprecision of Individual samplers.
3. With this approach, areas would be more likely to be determined as not
1n attainment with the standards. There would also be an Impact,
albeit small, on the design value and the development of control
strategies.
OPTIUN 3: Measurement data are submitted separately by each monitoring
agency. The data produced by each agency are treated as data produced by
different sampling stations.
Advantages
* \-
X?
1. This Intirprttatlon Is consistent with historical data usage for
collocated sampling by different monitoring agencies. It 1s also
stra1gtforward, simple to Implement and doesn't require any changes
to existing data processing software.
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APPENDIX 3
Page 72 of 86
2. The data produced by any monitoring agency using an approved reference
method sampler that satisfies all of the pertinent Part 58 requirements
can demonstrate that the site is in violation of the NAAQS and thereby
be used to protect public health.
3. When two or more agencies operate the same type of W^j sampler,
treating the agencies' data separately avoids the bias that could be
introduced by selecting the maximum dally collocated measurement.
(See disadvantage 2 under option 2 above.)
4. The advantages 2 and 3 discussed under option 2 above are also
applicable to this option.
Disadvantages
1. All measurements produced by approved collocated reference method
samplers estimate PMio air quality at a specific location. However,
with this option for treatment of data, measurements from only one
agency's samplers are sufficient to establish nonattalnment, while
measurements from each agency's approved samplers are necessary to
demonstate attainment. Therefore, this approach favors a sampler
which produces systematically higher measurements.
2. The disadvantages 1 and 3 discussed under option 2 above are also
applicable to this option.
OPTION 4: Allow the responsible control agency to submit a single set of
data for the location. This data set could be obtained by a)
designating a primary approved sampler or b) averaging data
from multiple approved samplers.
Advantages
1. The State would clearly be responsible for the one data set that would
be used for attalnment/non-attalnment decisions.
2. Designation of one sampler as the primary sampler 1s consistent with
existing duplicate sampler data usage, when a single monitoring agency Is
Involved.
3. This approach provides flexibility to the responsible control agency
1n decldlfio, how much weight should be placed on the supplemental
Information.
Disadvantages
1. Lack of specific guidance on how the additional measurement Information
would be used may produce Inconsistent use of data nationally and present
the potential for .Inconsistent data Interpretation among States and
Regional Offices.
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2U
2. Selectire use of reference method data which meets all of the Part 58
and Appendix K requirements may be in conflict with Appendix K to CFK
Part 50, which states that all data must be used. However, this approach
does not specify a uniform procedure in which the supplemental data must be
considered for attainment assessment.
3. In the case of averaging data, State Agencies might feel that the impact
of their data is being diluted by being combined with data from other
sources. Also, unless submission of all data for each monitor Is required
there would be no record of the Individual State monitor measurements.
4. This approach may be viewed as a departure from existing data usage
conventions wherein the highest reported values are currently used in a
multiple agency situation for all pollutants.
Recommendation
For the case when samplers are collocated for data quality assessment
purposes (I.e., precision and accuracy), It seems reasonable to recommend
that similar sampler types must be used, and one sampler must be designated
a priori for data reporting purposes. Furthermore, f f more than one type of
sampler Is used by a reporting organization, collocated precision sites
should be established for each sampler type.
When more than one sampler Is operated by one or more monitoring '
agencies for attainment assessment purposes, we recommend Option 3,
treating each agency's data as data produced by a different sampling
station. Me feel that this option Is more legally defensible, 1s consistent
with existing Interpretation of NAAQS pollutant measurement data, and
supports the Federal Reference Method approval process. We do expect the
multiple agency sampling situation to be common and certainly do not
encourage the collocation of different sampler types for routine air
quality monitoring and data reporting;
With a multiple agency sampling situation, one monitoring station
shall be designated as the SLAMS station and the others shall be
designated as SPM stations. Any special purpose ambient air quality
monitoring station, from which the State Intends to use the data as part
of a demonstration of attainment or nonattalnment or In computing a
design value for control purposes of the NAAQS, must meet all the
requirements for SLAMS (40 CFR Part 58.14), Including quality assurance,
monitoring mlftmods* and probe siting. This requires that a quality
assurance pffjram be described In detail, suitably documented and approved
by the apoHplate Regional Office (40 CFR Part 58 Appendix A).
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ATTACHMENT D Page 74of 86
10/12/88
DRAFT
MEMORANDUM
SUBJECT: Comments on Draft Position Papers on
FROM: William F. Hunt, Jr.
Chief, Monitoring and Reports Branch, TSD (MD-14)
TO: Chris Dunlap, Supervisory Auditor
Office of Inspector General (MD-53)
'\
The following are our comments on your three position papers on PM\Q.
As you know, your first two position papers correspond very closely in
content and Ideas to an Issue paper on PMiQ measurement uncertainty
developed by a joint EMSL/OAQPS committee which was established in March.
OAQPS 1s currently proceeding to Issue a revised policy regarding the
treatment of PM^Q data which follows the recommendations of this committee.
We feel that the recommendations of your position papers and the
EMSL/OAQPS Issue Paper are very close. Here are some specific points on
the three position papers.
1. Position Paper No. 1
Position Paper No. 1, entitled "EPA Need To Ensure That Different
Attainment Decisions Are Not Made Solely Because Of The Use Of Different
Types Of PM}Q Monitors," 1s well written and Is conceptionally very similar
in content and recommendations to the EMSL/OAQPS Issue Paper on PM}Q
Uncertainty.. In fact, many of your comments and recommendations are
addressed in this issue paper. In both reports, the Issue of potential
differences In PM^Q measurements near the PMio standard level is considered.
,The major difference, we feel, is in the approach recommended to implement
the basic Ideas. .In your report, you recommend that OAQPS consider
establishing a group of experts who would deal with specific situations
on a casttfby-case basis. Our approach was to assemble a group of experts
(the PMi$*9leasurement Working Group) to consider a broad range of options
for the treatment of PM}Q data produced by EPA approved and unapproved ""
samplers, and to recommend a general procedure to follow for all data
usage. We feel that our approach which specifies a general rule for
interpretation of PMjQ data is the proper approach which promotes and
encourages national consistency. We also desire to allow flexibility and
would do so by permitting deviations to the general rule provided that
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Page 75 of 86
these deviations receive concurrence of OAQPS. In practice, these
deviations would be reviewed by a panel of EPA experts. In fact,
a panel of EPA experts are involved in the review of SIPs and in the review
of air quality data to ensure that existing .SIPs do not require revision.
Under the Implementation regulations for PM^Q, areas are not classified
attainment or nonattainment and sanctions are not automatically imposed
because of a nonattainment designation. The critical issue is whether or
not the State Implementation Plans are adequate to attain and maintain
the standards. The review of air quality data with respect to the standards
Is just one step In the SIP process and does not cause any regulatory
action to occur by itself.
2. Position Paper No. 2
Position Paper No. 2, entitled "EPA Needs to Develop a Policy For
Dealing With The Fact That Regulations Do Not Allow Attainment Decisions To
Be Based On Most Of The PM10 Data Collected Through August 1. 1988," 1s
also well written and essentially discusses, the second data treatment of
the EMSL/OAQPS Issue Paper. Again, the Intended results are conceptlonally
similar and only differ slightly In Implementation. Unlike your Position
Paper No. 1, this paper does not reference the Issue Paper. We feel that
1t would be appropriate to do so. Before I compare recommendations, I
11st some specific comments:
Page 5: The SA 321-A Is not an approved monitor.
Page 7: "EPA cannot comply with Federal Regulations If It uses
PMio data from nonapproved monitors to make attainment decisions."
This statement Is not true. Appendix K permits exceptions to the
general rule that three years of [reference! PM^Q data are needed to
determine attainment, provided that approval 1s granted by the appropriate
Regional Administrator and Is 1n accordance with established guidance.
In the Guideline for Exceptions to Data Requirements for Determining
Attainment of Particulate Matter Standards, examples are Included to
serve as guides. One such example permits the use of TSP as a surrogate
PMio Indicator. The EMSL/OAQPS Issue Paper recommends that PM}o data from
.unapproved samplers can also be used as a surrogate PMig Indicator, subject
'to the conditions of the gray zone and provided that the unapproved data
1s only used to support and corroborate reference PMjg data. Regarding
your recommendations on Position Paper No. 2, I submit comments on each
of the six 1t<
(a) Under existing procedures, OAQPS already utilizes a panel of
experts to review air quality data as part of the SIP review process.
These individuals are representatives of the Regional Office and OAQPS
who review SIPs to ensure that the standards will be attained and properly
maintained and rev.iew data to ensure that existing SIPs do not require
additional revision.
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APPENDIX 3
Page 76 of 36
(b) and (c) The Issue Paper recommends that data from unapproved
samplers produced after August 1, 1988, not be used for making comparisons
with the standards. It does not differentiate between samplers which
were put in service before this date. EPA wants to ensure that all
nonreference samplers are replaced with reference samplers. If EPA
specified a general policy that permitted the continued use of nonreference
samplers, we feel that there would be no incentive to retire the older
instruments.
•
(d) We agree that flexibility is needed in order to make comparisons
with the standards, but prefer to do so by permitting exceptions to a
general rule as described by our comments to your Position Paper No. I.
(e) Our approach would be to set a general gray zone within which
nonreference PMjg data would be viewed with uncertainty and outside of
which the data would be used with more authority.
(f) Based on the comments, of our Office of General Counsel, we do
not appear to need any regulatory changes 1n order to implement
the recommendations of the EMSL/OAQPS Issue Paper.
3. Position Paper No. 3
Position Paper No. 3, entitled "Additional PMjg Monitors are needed
and OAQPS needs to Take A More Active Role To Ensure That Monitor
Requirements Are Met/ Implies that EPA Headquarters should be much more
Intimately Involved 1n the day to day management of activities which are
the formal responsibility of the Regional Offices. We disagree with this
approach and would like to emphasize that the Part 58 monitoring regulation
reinforces our position.
Page 1: The 16 identifies a deficit of 81 PM^ samplers which were
needed to fulfill the regulatory requirements. Pages 1-6 include a
detailed discussion of the Part 58 monitoring regulation as it applies to
the number of required monitors. This deficit of 81 samplers is mentioned
numerous other times throughout the rest of the position paper and is
used to make other assumptions and- conclusions.
\
HRB Response:
o As of March 31, 1988, a deficit of 81 PM^g samplers was
Identified to fully cover all NAMS, Group I, and Group II
areas.
o As of October 1988, the deficit is 11 samplers and 7 of the 11
are in the process of being purchased. (See Attachment A)
o Therefore, only 4 PMjg samplers are still needed.
o OAQPS is respondi n
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APPENDIX 3
Page 7y of 86
Page 6: The IG report discusses the designation of PMiQ samplers
by EMSL as reference instruments. They further state that nonapproved
monitors do not satisfy the regulatory requirements for a PM^Q monitoring
network."' Exhibit A of the report lists 9 types of unapproved samplers
which were operating at 386 sites in 1987.
MRB Response:
o The IG's Issue of approved versus nonapproved samplers has
essentially disappeared as noted below.
o As of October 1988, all of the SA321A samplers have been
converted to the SA321AG. The SA321AG is identical to the
SA321B which is a reference sampler.
o Reference designation has been applied for the SA254 medium
volume sampler and the SA246B dlchot. Discussions with MSB
indicate both should be approved in 1988.
o The SA244-E refers to a base and should be converted to the
SA246-B, and reference designation has been applied for.
o No application has been received for the Wedding dlchots
(GMW9200 and W-10)
o Information from ROs indicate no SA321 are in operation at this
time.
o Conclusion: Of the 603 PMin sites Identified by the 16 in
Exhibit A, 573 PMjg sites (95 percent) are using reference or
equivalent samplers.
Page 7: The IG raises questions that the shortage of 81 samplers may
be much higher because of (a) the number of NANS PM10 sites is unknown, and
(b) unapproved PMjn, samplers that cannot be modified must be replaced.
HRB Response:
The PMjg NANS networks have been approved for 44 of 49 States.
Based on the approved networks and the number of PMjg sites in the re-
maining 5 State networks under review, it is projected that the NAMS PM^Q
network will consist of 286 sites. The unapproved PM^g sampler issue has
been addressed.
Page 8, sixth sentence: Report notes that more PM^g monitors may be
required by the regulatory section of Part 58 because of the provision in
the regulation which allows TSP monitoring as a surrogate for PM^g SLAMS
monitoring. This provision requires that the surrogates be replaced with a
PM}g monitor if the surrogate measurements are above a certain level. In
the following two paragraphs, pages 8 and 9 of the report, the IG expands
their discussion of the surroyate concept in their attempt to show that a
significant number of new I'Mjg monitors would be required in Group 111
areas.
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APPENDIX 3
Page 78 of. 86
MRB Response:
The IG does not have a clear understanding of the Part 58 PM10
surrogate monitor provision. Their discussion and subsequent conclusion
implies that any existing TSP monitor is a SLAMS PM^Q surrogate and if
the TSP levels exceed the levels of the PMj0 standard the TSP monitor
would automatically be required to be converted to a PM^Q monitor. This
simply is not true. The PM^g surrogate provisions only apply to officially
designated SLAMS PM^Q surrogate samplers. If the State chooses to continue
running other TSP monitors, its their decision and there is nothing in
the regulations which prevent them from taking this action. The PMiQ
surrogate provision was included in the regulation as a PM10 network
design cost saving measure and allows the States to expand their approved
SLAMS network through the use of TSP samplers. The IG should be aware
that an area that has TSP levels that slightly exceed the PM^g standards
have a probability of exceeding the PMjg standards of less than 5 percent.
Encouraging the widespread placement of PM^g monitors in such areas would
be largely unnecessary.
Page 9, 1st and 2nd sentence, second paragraph: Preliminary Summary-
81 additional PM^g monitors needed on August 1, 1988.
MRB Response:
As noted earlier, more recent figures show the deficit to be only
four PM monitors.
Page 9: Did OAQPS either assess monitoring needs or confirm that
needs were reasonably assessed? Did OAQPS either take all practical
actions to meet present and future monitoring needs or confirm that such
actions were taken? Questions on Page 9, subsequent discussion on page 11.
Two IG conclusions were Identified on page 11:
(a) OAQPS does not know whether State, local or Federal funds
will be used to purchase needed PM^g monitors or to what
extent the need will be met.
(b) OAQPS has not fully assessed the need, or confirmed that
an assessment has been made of the need, to modify or
replace nonapproved monitors that are part of the current
SLAMS and NAMS network.
MRB Response:
IG's discussion on page 10 notes that the Monitoring Section Chief's
August 9, 1988, memorandum provides estimates of the projected future NAMS
and SLAMS networks but no worksheets or documents to support these estimates
were available. The report proceeded to note that the IG's earlier estimate
of the neod for 81 T*Mjg monitors was supported by IG workpapers which
identified the HI locations where monitors were needed. Implication here
is that if worksheets arc not available, any projections are unreliable
and t lie re fore inadequate. It must be noted that the IG's estimate of Ul
monitors was based on a highly detailed report prepared by the Monitor
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APPENDIX 3
Page 79 of 86
Section. (This report was the 13th of the series on the status of
monitors.) We believe that the Monitoring Section's August 9 projections
of NAMS/SLAMS PM^g monitors which were based on a combined MRB experience
with other NAMS/SLAMS network reviews, analyses and reports of at least
60 years were at the time precise enough for Headquarters needs. Since
then, MRB has formed a PM^g task force to review PM^Q monitoring networks,
identify any deficiences and develop recommendations for improvements.
This action should result in responses to many of the concerns raised by
the IG.
Page 11: The IG concluded that OAQPS does not know whether State,
local or Federal funds will be used to purchase needed PM^n, monitors or
to what extent the need will be met.
MRB Response:
The IG's conclusion reiterates our opening objection that the IG is
advocating an expanded management role for OAQPS which would involve
doing the work of the Regional Offices. MRB maintains the position that
the overall national PM^rj monitoring needs (Group 1 and II areas and NAMS)
are essentially being met (some fine tuning undoubtedly will be required).
Shortfalls that appear should be corrected by the $400K identified as a
line item in EPA's documentation supporting the President's Budget for
Fiscal Years 1989 and 1990.
Page 11; Report concludes that OAQPS has not fully assessed the
need, or confirmed that an assessment has been made of the need, to
modify or replace nonapproved monitors that are part of the current SLAMS
and NAMS network.
MRB Response:
As noted earlier, the problem of unapprtived monitors has been
resolved.
Page 12: The IG addressed the concern about how many States had a
standard for TSP and whether this .information was factored in the estimates
of disinvestment of TSP samplers. The IG concluded that OAQPS had not
made any significant attempt to gather this information from State/local
agencies. The report implies that the February 5, 1988, memorandum from
the Director, TSO, concerning TSP disinvestment only went to Region X.
MRB Response:
o In early 1988 preliminary information was gathered by MRB which
indicated that some States would retain a TSP standard for at
least 1 or 2 years. This information was factored into MRB's
estimate of the future TSP network. In August, MRB conducted a
survey of all the ROs on the current status of State TSP standards
and the number of TSP samplers that would be retained. All
Regional responses arc not in.
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APPENDIX 3
Page 30 of 36
o Concerning the February 5 memorandum, it should be noted that
similar memorandums were sent to all 10 Regions.
Page 12-13: The IG remarks that OAQPS officials should have placed
more emphasis on shifting PM^o samplers is based on the IG premise of a
deficit of 81 samplers.
MRB Response:
o The deficit of 81 samplers has already been discussed.
o Recommendations, as noted in the IG report, were included in the
last several PM^g Status Reports to provide coverage in the Group
I and Group II areas as needed.
o Memorandum from Director, ISO, on December 23, 1987, to Regional
Office ESD Directors' re-emphasized this recommendation.
o Region VIII moved approximately 20 PMjo samplers from one State
to a different State.
o Several Regions have moved SSI and dlchots for special studies.
Page 14; The report states that "Aside from providing policy and
publishing statistics, we believe OAQPS should be very active In: (1)
Identifying problems, such as failures to comply with Federal regulations
and EPA policies; (2) compiling Information related to solving the pro
(3) ensuring that all reasonable approaches to solving the problem are
known by the officials who can affect a change, and (4) ensuring that
Inaction, or Inadequate action, is brought to the attention of the highest
responsible official. Including the Assistant Administrator for Air and
Radiation. We believe the Director, OAQPS, should consider making a
policy statement regarding OAQPS1 role in Identifying the need for PMjQ
monitors and ensuring; that the need is met. We also believe that the
Director should ensure that a comprehensive analysis is completed of the
present and future need for PM^Q monitors." The report continues (pages 14
and 15) with detailed suggestions.on the contents of the comprehensive
.analyses.
MRB Response:
We agree in principle with the suggestions noted by the IG concerning
the actions OAQPS should be involved in. However, we are concerned that
the IG statements strongly imply that OAQPS did not take a strong proactive
role of ensuring implementation of the Part 58 PM\Q monitoring and data
reporting regulations. On the contrary we believe OAQPS took early,
effective steps at the highest management levels to implement the monitorim
examples. Four specific examples can be cited (a) 105 grants, (b) operating
guidance, (c) budget, and (d) the Agency's Strategies Planning and Managemei
System.
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APPENDIX 3
Page 81 of 36
In FY 86 OAQPS was successful in gettiny S400K. of IDS grant funds
allocated to the Regions for purchase of PM^Q monitors and related support
equipment. Approximately 40 PM^Q monitors were procured, in FY-87
Office of Air and Radiation guidance to the Regions recommended that
completion of the PM^o network was to be a hiyh national priority for use
of FY-87 grant funds and pointed out that amounts similar to those targeted
in FY-86 should be considered in FY-87. Records show a total of 49
monitors were procured by 105 funds in FY-87. In FY-88 a total of 74
monitors were purchased with 105 funds.
' The Agency uses the Annual Operating Guidance as a mechanism for
identifying the Administrator's major program goals and objectives and
allows the Assistant Administrators to identify the program areas that
should be given the highest priority. Since FY-86 establishment of
monitoring network has been included in the Agency's Operating Guidance.
FY-86/87 guidance directed the Regions to use FY-86 grant funds, when
required to purchase PM^o monitoring equipment. FY-87 guidance recommended
completion of the PM10 networks as a high national priority. In FY-88 the
Agency's guidance directed the Regions to provide technical and financial
support to assist States in establishing PM^o networks. FY-89, guidance
although less focused on purchases than in prior years, still directs
the Regions to closely monitor State and local Agency progress in
implementing the PMio monitoring regulations.
Measuring EPA and the States progress towards agreed-upon goals and
objectives 1s accomplished through the Agency's Strategic Planning and
Management System (SPMS). Since FY-86 some PM}o monitoring measures were
Included as SPMS activities. In FY-86, we tracked Regional Office purchase
of PMio monitors with grant dollars as well as other PM^n network develop-
ment actions. FY-87 SPMS covered the tracking of the establishment of
PMio network and the submittal of PM^Q network descriptions. In FY-88,
five PMiQ measures were tracked and most targets were met indicating that
a very high percentage of the Group V and II areas are being adequately
monitored.
Page 15: The IG recommends these actions be taken by the Director,
OAQPS.
MRB Response;
We totally disagree with this recommendation. We believe that MRB
has had a. thorough and clear understanding of the various PM^Q issues
raised by the IG report and likewise understands the Branch's responsibility
in ensuring that identified needs are met. We refer to the various
management and staff actions taken since FY-86 towards implementing the
monitoring and data reporting regulations.
We agree with the second recommendation that a comprehensive analysis
of PM^o monitoring needs to be conducted, and refer to the formation of the
PMjQ task force as an example of a significant positive action towards tins
yoal .
cc: vi. l.axton
U. Tyler
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APPENDIX 3
Page 3 2 of 36
October 12, 1988
NOTE TO BILL HUNT
SUBJECT: Comment on SIP Development for Response to
IG's Draft Position .Paper 12
The process of developing a State implementation plan (SIP) starts-
with a periodic evaluation of air quality data to determine if violations
of the national ambient air quality standards have occurred. Once violations
occur, all data are considered when determining which sources to control.
Analysis conducted by air quality dispersion modeling plays an integral
role in this process. Thus, monitoring only begins a process wherein
dispersion modeling and other analyses provide an independent assessment
of the controls, if any, which might be needed. Erroneous data could be
identified by this independent assessment. Also, in the case of PHiQ,
the areas with the worst PMio problems were classified as Group I based
on total suspended particulate data (see FR 29383, August 7, 1987). We are
requiring States to submit SIP's for these areas regardless of the type
of PMo monitor used.
-------
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-------
APPENDIX 3
ATTACHMENT E . Pa§e 8 5 of 86
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
1 Office of Air Quality Planning and Standards
/ Research Triangle Park. North Carolina 27711
DEC 2 3
MEMORANDUM
SUBJECT: Status Report for PMjQ Samplers
FROM: William G. Laxton, Acting Director
Technical Support Division (MD-14)
TO: Director, Environmental Services Division, Regions I-VIII, X
Deputy Director, Office of Policy'and Management, Region IX
Attached 1s a copy of the twelfth quarterly "Status Report of PM}g
Samplers," which reflects the status as of September 30, 1987. Tables
are presented which show the location of the operating and future samplers
by urbanized areas. As of this date, there were 884 samplers operating
at 550 sites with another 14 samplers scheduled to begin operating by
December 31, 1987. Of the 662 samplers EPA supplied to the Regions In
1984, 641 (97 percent) are being utilized.
The status report provides Information on the number of operating
PMiQ sites submitting data to the NADB. Also, the data completeness was
calculated and shown for those sites which reported data. An overview
describes the national coverage of PM^rj samplers,and sampling frequency
according to the PMiQ monitor groupings. The groupings were.deterralned
by the Regions based on the 1984 to 1986 TSP/PM10 data base.
Several problem areas exist and your assistance 1s needed to resolve
the following:
(1) No start date has been specified for the remaining 21 samplers
distributed In August 1984, although I understand that approximately 9 of
the 22 samplers are 1n the process of being relocated. These samplers
need to bttput Into the network. Also, 40 of the SI samplers targeted
for prociMfttnt with EPA FY-86 funds have been purchased and only 13 have
been Identified as being operational. The remainder of these samplers
need to be purchased and put Into operation.
(2) Twenty-three States have been Identified as operating 66 PM10
samplers which submitted no data to the NADB for 1983 through the second
quarter of 1987. The report shows that data submlttals to NADB are very
-------
APPENDIX 3
2 Page 86of 86
slow. For 1985 there are still 29 operating sites which have no data on
AIRS. For the 4 quarters of 1986 the percentages of sites reporting data
are 89, 89, 88, and 87 percent, respectively. Only 51 percent of the
operating sites reported data for the first quarter of 1987 and 5 percent
for the second quarter. For PM^g data submitted to NADB, the data
completeness for 1983 to 1986 ranged between 85 and 87 percent. You are
requested to look into the problems associated with data submittals so
that the data will be submitted in a timely fashion.
(3) As noted in Table 17, there are still some problems with the
PM}g sampler coverage in the high and medium nonattainment probability
areas/counties. Seven of the high probability areas (distributed among
Regions V, VIII, IX and X) and 24 of the medium probability areas/counties
(distributed among Regions III, V, VI, VIII, and IX) do not have any
PMjo samplers. Also, for the high and medium probability areas, there are
33 and 38 areas/counties, respectively, which do not have a site operating
at the required minimum sampling frequency. Immediate action should be
taken to place samplers in the high probability areas/counties not
presently covered. In addition, samplers should be placed 1n medium
probability areas/counties (excluding the fugitive dust counties) with
priority given to those areas/counties having a probability >. 50 percent.
I understand from the 1988 SPHS commitments that most of these areas will
be covered during FY-88.
(4) There are 145 sites 1n 33 States which still have errors In the
Interim parameter codes, duplicate data, or AIRS site file. Your assistance
in getting these problems corrected 1s also requested.
Also attached 1s a 11st of specific problem areas for your Region, n
realize that some of these may have been resolved by now, but urge you to
resolve any remaining problem areas.
Attachments
cc: 6. Emison
W. Hunt
J. Puzak
Director, Air Management Division, Regions I, III, V and IX
Director, Air and Waste Management Division, Region II
Director, Air, Pesticides, and Toxic Division, Regions IV, VI
Director, Air and Toxics Division, Regions VII, VIII, X
SAMWG Members
ALAPCO Monitoring Committee
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APPENDIX 4
Page 1 of 14
ADDITIONAL PIG COMMENTS TO FEBRUARY 24. 1989
RESPONSE TO DRAFT AUDIT REPORT
The following notes present our responses to Office of Air and
Radiation (OAR) comments which are not addressed in body of the
report.
Note 1
The Acting Assistant Administrator suggests that we discuss
"... the inherent possibility of differences between sampler
types due to the complexity of particulate matter in the
atmosphere and the trade-off made by EPA between flexibility in
design and measurement uniformity ..." The Acting Assistant
Administrator believes that our draft report discussion is
"incomplete" and "oversimplifies the issue" because we have not
included a summary of the information in the introduction to
EPA's Issue Paper (pages 54 through 56 of Appendix 3), which
discusses the subject in technical terms.
We believe that including this information would obscure our
overriding point that regardless of "inherent differences" and
"trade-offs", the fact remains there is a relatively consistent
pattern for one monitor type to read higher than the other
monitor type.
Note 2
The Acting Assistant Administrator describes key elements of the
policy established on November 21, 1988. We discuss all of
these elements in the body of our report except the following:
Site specific information regarding measurement
differences among reference method samplers is
simply not available to permit a panel of experts
to Judge PM10 measurement acceptability.
We recognize there are "site" measurement differences that may
never be known. However, it is known that there are measurement
differences between the primary types of approved monitors and
these differences have been quantified in different parts of the
country. We do not believe the inability to eliminate all
measurement bias should prevent EPA from eliminating that part
of the bias that EPA knows about and can estimate. If the
presently available information about differences between
monitors is not sufficient ". . .to permit a panel of experts
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APPENDIX 4
Page 2 of 14
to judge PM10 measurement acceptability," then SIP experts must
be expected to ignore all of the information that is known about
differences between monitor types.
Note 3
We have clarified our report on page 7.
Note 4
The Acting Assistant Administrator states that, "... areas
are not classified as being out-of-attainment with the new
particulate matter standards." In a memorandum to us, dated
February 24, 1989, the Acting Assistant Administrator explains
this statement:
There is some subtlety involved with the terminology
"attainment status." The new implementation regula-
tions for PM10 do not require that an area's status
be formally classified as attainment or nonattain-
ment. Instead ... an area's SIP is judged to be
adequate or inadequate to demonstrate attainment with
the NAAQS.
In our opinion, it is meaningful, if not technically accurate,
to refer to areas as being "in attainment" or "out-of-attain-
ment ". We know from our fieldwork that: this terminology is
used by EPA personnel, State and local government personnel, and
private industry, and that it is used in Office of Air and
Radiation correspondence. In our opinion, it is not essential,
and would not be constructive, to amend our report by replacing
the common expression that an "area is out-of-attainment" with
the statement that an "area's SIP is judged to be inadequate to
demonstrate attainment with the NAAQS." We also believe that it
would not be constructive to provide a footnote about the
"subtlety involved with the terminology" every time we use the
expression "attainment" or "nonattainment" in our report. We
believe the Acting Assistant Administrator's comments, and our
consideration of them in these appendices to the final report,
will provide ample record of the subtleties in terminology.
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Note 5
The Acting Assistant Administrator's comments have not caused us
to change our opinion. We do not believe these groups will cease
to oppose control measures, that may cost them money and jobs,
simply because of the information about modeling, etc., which is
contained in the Acting Assistant Administrator's response.
Note 6
We changed the clause "any 24-hour period" to read "any 24-hour
period measured from midnight to midnight". (See page 10 of the
report.)
Note 7
The statement in our draft report was qualified by the word
"generally" and we have retained this wording in our final
report.
Note 8
Our report contains a lengthy quote from the Chief, Methods
Standardization Branch (see page 11) which addresses the reasons
that EPA-approved monitors produce different measurements. We
have included the Acting Assistant Administrator's additional
comments on this subject on page 11 of the report.
Note 9
We understand that nonapproved monitor data from 1985 and 1986
that is outside of the gray zone may be used with data from 3
years later. The Acting Assistant Administrator's response does
not consider this possibility.
The Acting Assistant Administrator also states that this section
of the report ". . . leaves the reader with the impression that
progress In solving the problem with these samplers has not been
made." We believe any such impression should be attributed to
the statement we quoted, not any opinion which we expressed. For
example, we quoted the Chief, Methods Standardization Branch:
"Although improvements in PM10 technology should result in
samplers with better agreement, differences are allowed and
likely will continue to occur." Our opinion is contained in our
statement "... the technology for measuring particulate matter
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concentration appears to have improved in recent years and
narrowed the measurement differences between the two types of
PM10 monitors ..."
Note 10
We have changed our wording on page 12 of the report. We used
the term "significant" in our draft report because we understood
that while measurement differences are decreasing the amount of
difference is of concern to OAR. For example, the PM10 Task
Force stated that "The magnitude of this uncertainty, which
appears to be somewhat greater than corresponding uncertainties
associated with gaseous pollutants, raises questions and concerns
about the utilization of PM10 data in the determination of the
attainment of the NAAQS and in the development of SIPs."
Note 11
We have not raised any issue concerning the merits of the
equivalent method concept. We continue to believe that detailed
discussion of the equivalent method concept is beyond the scope
of our report.
Note 12
The point of our discussion is simply to illustrate that a
monitor may only show a few exceedances over an extended period
of time that are very close to the standard. This point does not
depend on whether the monitor was approved or not approved, we
have not suggested that the OAR take action, or not take action,
based on the actual measurements of the specific monitors at the\
two areas we discuss. If all areas that did not have 3 years of I
data from approved monitors were excluded from our consideration
there would be little, if any, opportunity for us to evaluate
whether situations like Longmont, Colorado and Fresno, Californii
are likely to occur.
Aside from this consideration, we note that at the time we
identified the Longmont and Fresno areas, EPA's policy was to
accept the data from nonapproved (nonreference) monitors at fde-
value (i.e., there was no distinction between data from approve-
and nonapproved monitors for purposes of evaluating compliance
with the PM10 standard). As of November 21, 1988, the measure-
ments we cited in our draft report from Longmont and Fresno wou
be treated as an "uncertain data value" for purposes of evaluat
ing compliance with the PM10 standards
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APPENDIX 4
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. . . a PM10 value produced by a nonreference
sampler which is in its gray zone is not treated as
an exceedance of the NAAQS nor is it treated as a
nonexceedance of the NAAQS (i.e, it is treated as an
uncertain data value for purposes of making comparisons
with the NAAQS). . . .
By following this policy, we believe that attainment decisions
for areas with nonapproved monitors will be delayed because the
measurements fall within the gray zone.
We do not believe we could improve the clarity of our report by
discussing these issues in the body of our report. Therefore, we
have not changed the wording in our final report.
Note 13
We have revised our report to indicate that a new policy is no
longer pending.
Note 14
The Acting Assistant Administrator states that the new policy
which was adopted on November 21, 1988 was determined to be a
better course of action than the two options which the committee
examined and we reported. We did not develop either of these
options or recommend that they be adopted. We merely learned of
their existence from a committee member and reported their
consideration for the dual purpose of disclosing ongoing develop-
ments and illustrating flexible options to accepting monitor
measurements at face value.
Note 15
The Acting Assistant Administrator states that setting a general
policy which allows "exceptions" is the preferable course of
action, W* discuss our understanding of this policy in the body
of our report. In this note, we will only comment briefly on
the reference to "exceptions". We do not understand what this
term means in the context of evaluating PM10 data. For example,
does someone or some group decide, on a periodic basis, that
continuous monitor measurements above the standard should not
ultimately call for action to reduce PM10 levels? If so, are
there any criteria for making these decisions? If there are such
criteria, are the decisions documented? To our knowledge, such
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APPENDIX 4
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actions are not currently taken and are not contemplated for the
future. We do not know what type of actions would represent
"exceptions" under OAR's new policies. We presume the concept
does not refer simply to situations where data is known to have
been distorted, such as high PM10 measurements that are caused by
a forest fire.
Note 16
The Acting Assistant Administrator suggests that we amend a
statement in our draft report to specify ". . . that the
committee recommended that PM10 measurements from EPA approved
reference method samplers be accepted at face value." According
to our understanding of the new policy, this statement would be
incomplete. It does not say that measurements from a dichot
monitor, which is not an EPA-approved monitor, may also be
accepted at face value if these measurements were recorded prior
to July 31, 1988. (See page 52 of Appendix 3). We do not want
to add this degree of complexity to the body of our final report.
In addition, we believe it is very clear from the report context
(one sentence before the questioned sentence) that we are on
talking about the two primary types of EPA-approved monitors
are not making any statement at all concerning the committee's
recommendation about accepting data from nonapproved monitors.
For these reasons, we have not changed the wording in our final
report.
Note 17
Based on the Acting Assistant Administrator's comments, we remain
concerned that when measurements are near the standard, EPA will
make different attainment decisions solely based on the type of
monitor used.
Note 18
We have never suggested that data be "adjusted" in the sense that
it would be changed. Allowing a panel of experts the flexibility
to interpret monitor measurements does not mean that data needs
to be adjusted.
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Note 19
The Acting Assistant Administrator indicates "... that the
appropriate role for a group of experts is to review PM10 SIPs,
and not to review all measurements within a specific range." We
agree that PM10 experts should review PM10 SIPs and we have not
written anything that implied otherwise. We do not believe there
is necessarily any redundancy between reviewing SIPs and evaluat-
ing how the face value of a measurement should be interpreted.
Note 20
In response to the second recommendation in our draft report,
the Acting Assistant Administrator states: "The SIP, therefore,
provides for the appropriate regulatory documentation." We
agree. The Acting Assistant Administrator apparently interprets
our second recommendation as being a critical comment, perhaps
implying that attainment decisions should be documented in a
different way. Our second recommendation presumes that the
first recommendation is accepted and a change is made. If a
change is made, such as periodically convening a panel of experts
to evaluate all measurements near the standards, the panel's
discussions and decisions should be carefully documented.
Note 21
Our third recommendation presumes that the first recommendation
is accepted and a different course of action is followed. We
agree that if no change is made, no regulatory changes are
needed.
Note 22
We agree with the Acting Assistant Administrator's response that
"The November 21 policy memorandum clarifies the use of data from
nonapproved monitors." We discuss this clarification in several
sections of our final report, including the summary section.
Note 23
We have amended our final report to indicate that EPA, not MSB,
approves equivalent methods for sampling PM10.
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APPENDIX 4 ,
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Note 24
On September 27, 1988 we provided copies of our position paper on
this subject to the Chief, Monitoring Section, Monitoring and
Reports Branch, Technical Support Division, OAQPS and to the
Chief, Methods Standardization Branch, EMSL. We did not
receive any comments regarding questions of fact.
On March 16, 1989, we met with the Chief, Methods Standardiza-
tion Branch. As a result of this meeting, we made minor changes
to four sentences in our final report to incorporate the Chief's
comments. Each of the four sentences which we changed were
present, verbatim, in our September 27, 1988 position paper.
Note 25
The subject paragraph in the draft report is virtually identical
to the paragraph in our position paper which we provided on
September 27, 1988 to the Chief, Monitoring Section, Monitoring
and Reports Branch, Technical Support Division, OAQPS and to the
Chief, Methods Standardization Branch, EMSL. The paragraph
states what we were told at the time the interview was condu
This paragraph is qualified in two separate instances to in
that the presented information applies to the situation "as of
August 1, 1988."
On March 16, 1989, we met with the Chief, Methods Standardization
Branch, and learned that the paragraph was no longer accurate
because new developments had taken place either since we issued
our draft report or since we held the interview. Specifically,
the manufacturer referenced in the paragraph has reportedly sub-
mitted the referenced monitors for evaluation by EPA personnel.
We do not believe this new information materially impacts our
final report and have not made any other changes.
Note 26
According to the Acting Assistant Administrator, OAR and the
Office of General Counsel believe that the authority to use data
from nonapproved monitors can be inferred from Section 2.3 of
Appendix K. We have not changed our draft report discussion of
this issue primarily because we want to document our concern
with the regulations.
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APPENDIX 4
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We also continue to believe that data from nonapproved monitors,
such as those from Medford, Oregon, which are far above or below
the standard, should be used without data from approved monitors
in making attainment decisions. The November 21, 1988 policy
does not allow data to be used in this manner.
Note 27
In our draft report, we indicated the Issue Paper recommended
that measurements from nonapproved monitors within the gray zone
should be disregarded. In our final report we added wording to
make it clear we were discussing disregarding the measurements
"for purposes of making attainment decisions." To ensure that
we addressed the Acting Assistant Administrator's concern, we
have included his following response in our final report:
"... measurements within the gray zone should not be
disregarded but used with less authority. "
In our draft report, we also indicated that measurements out-
side of the gray zone should be taken at face value. In our
final report, we also added the wording, "for purposes of making
attainment decisions" and, to ensure the Acting Assistant
Administrator's concerns were addressed, we included his follow-
ing responses "measurements outside the gray zone should be
considered more authoritatively . . . [and measurements] greater
than their respective gray zone . . . would be treated as
exceedances of the standard."
Note 28
The Acting Assistant Administrator presents various reasons,
including "concern for human health and welfare", for why data
from nonapproved monitors should be used to corroborate data
from approved monitors. We agree. Our concern is that the
regulations do not clearly allow this to be done.
Note '
In our final report, we have qualified the wording to indicate
that the committee's recommendation was to use data with "less
authority." We. understand this to mean that OAR will essentially
ignore data from nonapproved monitors in the gray zone when
determining whether an area is out-of -attainment. (See note 27
above . )
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APPENDIX 4
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Note 30
Since the action we recommended in our draft report has been
taken, we have deleted this recommendation.
Note 31
Our draft report presented an estimate of monitor needs as of
August 1, 1988. The draft report also referred to subsequent
OAQPS information which we analyzed. In our draft report, we
concluded that the number of monitors needed was less (as of a
different point in time) than the estimate we made. However, we
do not agree with OAR's conclusion that only four monitors were
needed as of October 1988 for the reasons discussed on page 42
of the report. (We have included additional reasons in our final
report.)
Regardless of our disagreement over the exact number of monitors
which were needed at a particular point in time, our primary
focus was, and is, the effectiveness of OAQPS actions to ensure a
complete system is in place. We believe that the results of our
inquiries on various issues (see pages 43 through 47 of the
report) indicate that OAQPS needs to take a more active role.
In regard to this issue, the Acting Assistant Administrator
raises a question repeatedly throughout his response to our draft
report. This question is whether we "fully utilized" certain
information. The Acting Assistant Administrator states:
"... the 16 auditors were provided with
updated information by OAQPS on October 12,
1988 by memo and meeting. This information
showed that only four PM10 samplers were
needed to fully cover all Group I and II
areas as well as meeting all of the NAMS
requirements. The 16 draft audit report did
not fully utilize the material provided on
October 12 but instead focused on an outdated
estimate of an 81 monitor shortfall."
Our draft report and final report clearly quoted the October 12
memorandum in detail, and we clearly identified how we used the
informations
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APPENDIX 4
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"During our fieldwork, we communicated our preliminary
conclusions to the Chief, Monitoring and Reports Branch
(Branch Chief). On October 12, 1988, the Branch Chief
provided preliminary comments on our estimate. Using
data recently obtained from the regional offices, the
Branch Chief wrote us:
o As of March 31, 1988, a deficit of 81
PM10 samplers was identified to fully
cover all NAMS, Group I, and Group II
areas.
o As of October 1988, the deficit is 11
samplers and 7 of the 11 are in the
process of being purchased.
o Therefore, only 4 PM10 samplers are
still needed.
o OAQPS is responding to the present and
future deficit through $400 K [$400,000]
in the FY-89 budget. TSD [Technical
Support Division] is preparing a memo-
randum to ROs [regional offices] to
actively pursue the use of these funds
to procure needed PM10 samplers.
Based on the additional information provided by the Branch
Chief, we updated our information and modified our
conclusions. We agree that some of the 81 sites which we
identified no longer needed PM10 monitors as of October 12,
1988. However, we do not agree that only 11 sites still
needed PM10 monitors because . . ."
Note 32
The Acting Assistant Administrator expresses "strong disagree-
ment" wita our conclusion that OAQPS has "not fully assessed" the
need for more monitors. We understand that the desire to fully
assess monitor needs was the reason that OAQPS formed a special
task force on August 9, 1988 ". . .to review PM10 monitoring
networks, identify any deficiencies and develop recommendations
for improvements." (See page 79 of appendix 3.)
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APPENDIX 4
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After expressing disagreement with our conclusion, the Acting
Assistant Administrator discusses expected future developments
("reference designators" are pending) and coding problems. Our
conclusion that OAQPS had "not fully assessed" the need for more
monitors was not based, at all, on the coding problems that are
discussed in the response to the draft report, or the status of
the PM10 network at a time after we completed our evaluation.
Our conclusion was based solely on the answers to the questions
we asked, including those identified in our draft report. (See
pages 43 through 47 of the report.)
We did not ignore the coding problem or choose "to ignore the
EPA information". As indicated by the Acting Assistant Adminis-
trator in his response to our draft report: "It is not clear why
the IG auditors have chosen to ignore the EPA information." Our
evaluation of this data was the reason our draft and final
reports stated: "We agree that some of the 81 sites which we
identified no longer needed PM10 monitors as of October 12,
1988."
Note 33
Our draft report contained virtually every bit of information^^!
this subject that we were provided. Our draft report stated" In
his draft memorandum to us, dated October 12, 1988, the Branch
Chief indicated that some preliminary information had been
gathered in early 1988 on the subject, and that the results of
an ongoing survey had not yet been finalized:
In early 1988 preliminary information was
gathered by MRB [Monitoring and Reports
Branch] which indicated that some States
would retain a TSP standard for at least 1
or 2 years. This information was factored
into MRB'a •estimate of the future TSP network.
In August, MRB conducted a survey of all the
ROs [regional offices] on the current status of
State TSP standards and the number of TSP
samplers that would be retained. All Regional
responses are not in.
Note 34
The Acting Assistant Administrator provides a great deal of
information concerning TSP networks and shifting resources form
TSP monitoring to PM10 monitoring. We generally agree with all
the information presented except the implication that is
buted to us in his following statement:
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APPENDIX 4
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However, what is implied in the IG report
is that as resources are decreased from TSP
sampling, more resources would be available
for procurement of PM10 samplers to meet the
IG deficit of 81 samplers.
Our concern is the same as that expressed by the Acting Director,
Technical Support Division, in a memorandum on February 5, 1988:
"Because of our mutual concerns about cost-effective monitoring
programs and the need to identify real and timely disinvestments
it
• • •
Note 35
During our audit, we reviewed the Status Reports and the
December 23, 1987 memorandum referred to by the Acting Assistant
Administrator. Our draft report quotes the same Acting Director
on the same subject a year later. Our draft report identified
the type of documents or records which would likely have caused
us to reach a different conclusion, including "notices of ...
plans to shift monitors" . . ., explanations of ". . . why each
monitor that remained in a Group 3 area had not been shifted to a
Group 1 or Group 2 area?"
Note 36
As discussed in note 31, we do not agree that only four monitors
were needed as of October 12, 1988. Prior to this estimate, we
asked OAQPS officials how additional monitors would be funded.
Our point is that OAQPS officials did not obtain information
including documentation which we believe would assist them in
assessing monitor needs on a national basis.
Note 37
The Acting Assistant Administrator states there will soon be
few, if any/ nonapproved monitors in the monitoring networks
which concern EPA. We concur that when this becomes a fact,
questions about nonapproved monitors would not have an impact on
an EPA analysis of monitoring needs.
Note 38
As discussed in note 31, we do not agree that the system was
complete as of October 1988. Moreover, additional monitors will
be needed to implement regulations which become effective in the
future.
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APPENDIX 4
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In our draft report, we suggested areas for OAQPS to study. If
an issue is no longer relevant, we believe it would be useful to
document this.
We also note that this review was conducted solely by OIG
auditors; no OIG investigators were involved. OIG investigations
have criminal implications.
The Acting Assistant Administrator also comments that the OIG
apparently did not critically review the valid monitoring
objectives allowed by Part 58 of the regulations. The issue of
shifting monitors from Group 3 areas to Group 1 and Group 2 areas
was originally raised by an OAQPS Section Chief. We recognize
that these are valid monitoring objectives for Group 3 areas.
However, Group 3 areas are expected to have the least PM10
pollution. Therefore, when assessing monitor needs, we believe a
valid area for study is the shifting of monitors from Group 3
areas.
We are confused by the following statements by the Acting
Assistant Administrator:
. . . PM10 samplers are needed to meet different
monitoring objectives. The IG auditors apparently
believe that PM10 samplers should only be located
to measure in maximum concentration areas.
Our draft report and final report state:
We recognize there may be many good reasons for
operating a PM10 monitor in an area where Federal
regulations do not require monitoring. For example
. . . [etc.].
Concerning the Acting Assistant Administrator's comments regard-
ing "private or industrial sites," we are unsure how this
statement applies to our report because we are referring to
monitor needs for the SLAMS and NAMS networks.
Note 39
We believe that aging monitors, or component parts of monitors,
should be considered in planning for future monitoring needs. We:
presume the Acting Assistant Administrator agrees. We do not
believe it would be constructive to revise our draft report to
differentiate between component parts, housings, etc.
Note 40
Our response is explained on page 51 of the report.
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