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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                                              APPENDIX 3
                                              Page 1 of 86



              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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                                              APPENDIX 3
                                              Page 2 of. 86
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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                                              APPENDIX 3
                                              Page  3 of 36
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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                                        APPENDIX 3
                                        Page 4 of 86
     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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                                             APPENDIX 3
                                             Page 5 of 86
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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                                         APPENDIX 3
                                         Page 6 of 86
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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                                              APPENDIX 3
                                              Page 7 of 86
          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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                                              APPENDIX 3
                                              Page 8 of 86
                                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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                                             APPENDIX 3
                                             Page 9 of 36
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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                                              APPENDIX 3
                                              Page 10 of 86


          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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                                              APPENDIX 3
                                              Page 11 of 86


          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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                                             APPENDIX 3
                                             Page  12 of 86
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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                                              APPENDIX 3
                                              Page 13 of 86
          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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                                             APPENDIX 3
                                             Page  14 of 86
          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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                                              APPENDIX 3
                                              Page 15 of 86


          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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                                              APPENDIX 3
                                              Page 16 of 36
          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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                                              APPENDIX 3
                                              Page  48 of 86
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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                                       APPENDIX 3
                                       Page 49 of 86
        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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                                               APPENDIX 3
                                               Page 50 of 86
             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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                               APPENDIX 3
                               Page 5 1 of 86
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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                                      APPENDIX 3
                                      Page 52 of 36
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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                                                      APPENDIX 3
                                                      Page 53 of 86

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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                                                    APPENDIX 3
                                                    Page 54 of 36
     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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                                                     APPENDIX 3
                                                     Page 55 of 86
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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                                                     APPENDIX 3
                                                     Page 56 of 36
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
                                                     Page 57 of 86
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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                                                     APPENDIX 3
                                                     Page 58 of 86
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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                                                    APPENDIX 3
                                    7               Page 60 of 86


                                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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                                                    APPENDIX 3
                                                    Page 6 1 of 86
                                    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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                                                      APPENDIX 3
                                                      Page 62 of 86
                                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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                                                     APPENDIX  3
                                                     Page  63 of  86
                                    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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                                                     APPENDIX 3
                                                     Page 64 of 86
                                    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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                                                    APPENDIX 3
                                                    Page 6 5 of 86
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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                                                     APPENDIX 3
                                    13                Page 6 6 of 86



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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                                                    APPENDIX 3
                                                    Page 6 7 of 86



                                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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                                                     APPENDIX 2
                                    lb               Page 68 of.36


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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                                    16
                                                    APPENDIX 3
                                                    Page 6 9 of 86
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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                                                     APPENDIX 3
                                    17               Page 7 D if 36


     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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                                    19
                                                      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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                                                     APPENDIX 3
                                                     Page 73 of  86
                                    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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                                                   APPENDIX 3
 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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                                                    APPENDIX 3
                                                    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.

-------
                                                   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.

-------
                                                   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

-------
                                                  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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                                                  APPENDIX 4
                                                  Page 3 of 14
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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                                                  APPENDIX 4
                                                  Page 4 of 14|


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
                                                  Page 5 of 14
      .  .  . 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
                                                  Page 6 of 14


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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                                                  APPENDIX 4
                                                  Page 7 of 14
 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 ,
                                                  Page 8 of 14
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
                                                  Page 9 of 14


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
                                                  Page 10 of 19
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
                                                  Page 11 of 14


     "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
                                             Page 12 of 14


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
                                             Page 13 of 14
     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
                                                  Page 14 of 14


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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