GUIDELINE  SERIES
           OAQPS NO.
1.2-011 (Revision.)
     GUIDELINES FOR DETERMINING THE NEED FOR
     PLAN REVISIONS TO THE CONTROL STRATEGY
           PORTION OF THE APPROVED
          STATE IMPLEMENTATION PLAN
   US. ENVIRONMENTAL PROTECTION AGENCY
     Office of Air Quality Planning and Standards
      Research Triangle Park, North Carolina

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PSCISCWQJ

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                          TABLE OF CONTENTS



                                                                     Page

     I.  Introduction 	  1

    II.  Responsibilities in Implementing Plan Revisions  	  5

         A.  Regional Offices	5
         B.  Headquarters 	  7
,:(       C.  Alternate Responsibilities	8

«*'•• III.  Procedures for Determining Whether a SIP/Control
         Strategy Needs to be Revised	10

         A.  Identification of Problem Air Quality Control Regions  . 10
         B.  Review of Specific Conditions within Individual AQCR's . 14
v)           1.  Evaluation of Data	15
C           2.  Analysis of Control Strategy 	 18
 «            3.  Available Analytical  Techniques  	 21
"                 (a)  Abbreviated Roll-back Procedure 	 21
                 (b)  Modified Roll-back  	 23
\J               (c)  Diffusion Modeling  . •	23
s       C.  Determination for Need for Plan Revision	25

    IV.  Procedures for Requiring Plan Revision 	 26

         A.  Plan Revision Documentation  	 26
         B.  Notification of State and Public	26
             1.  Federal Register Notice  	 27
             2.  Other Federal  Register Actions 	 32
             3.  Letter to the Governor	33

         C.  Plan Submittal	34

     V.  Overview of Necessary Action  in Relation to Substantially
         Inadequate SIP's 	 35

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                    I.   INTRODUCTION






     Section 110 (a)(2)(H)  of the Clean Air Act,  as  amended requires



that State Implementation Plans (SIP's) provide "for revision,  after



public hearings, of such plan (i) from time to time  as  may be  necessary



to take account of revisions of such national  primary or secondary ambi-



ent air quality standard; or the availability  of  improved or more  expe-



ditious methods of achieving such primary or secondary  standards;  or



(ii) whenever the Administrator finds on the basis  of information  avail-



able to him that the plan is substantially inadequate to achieve the



national ambient air quality primary or secondary standard which it



implements".  (Emphasis added)



     While the Act specifically identifies two reasons  why SIP's can



and must be revised, this guideline deals mainly  with the second category,



i.e., plan revisions to the SIP which are deemed  necessary on  the  basis



of information which indicates the approved SIP control strategy is sub-



stantially inadequate to attain and maintain the  national standard it



implements.



     It is the Regional Administrator's responsibility  to identify any



SIP which is substantially inadequate to attain national standards and



to call for a plan revision where necessary.  Such  determinations  are



to be made in Fiscal Year 1976 for all areas of the  nation (i.e.,  both



AQMA's and non-AQMA's)  for each criteria pollutant  (i.e., TSP,  S02> CO,



0  and N09).  Calls for revision to those existing  SIP's which  are sub-
 X       L.


stantially inadequate for attainment must be publicly announced without



proposal prior to July  1, 1976.  These calls for  revisions  must specify

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the schedule for submission of revisions  and must  require  that,  to  the
extent needed to meet national primary standards,  all  emission  limitations
which it is reasonable to anticipate will  be achievable within  a reason-
able period of time must be submitted by  the State by  July 1,  1977.* Any
other control measures (generally referring to transportation  controls
and land use measures) necessary for attainment and maintenance  must be
submitted by the State by July 1, 1978.   (NOTE: This  is not intended to
imply that some land use and transportation measures are not considered
reasonable.  These measures,  though  considered reasonable, generally
require more time to implement due to need to obtain enabling  legislation.)
      While the  Act  requires  attainment of  both primary  and  secondary
standards, priority  attention shall  be addressed  to attainment  of  primary
standards.  However,  it is recommended that when  plan  revisions  are
called  for attainment of primary standards  that they  also be adequate
to provide for  the  attainment of secondary standards.   Further,  any plan
revision for attainment of national  standards  shall also  consider
maintenance of  such  standards.
      The decision to  call  for a plan revision  should  be made only  after
 detailed analysis of the status of air quality; the restrictiveness
 of the  existing regulations; the status  of major  compliance actions  and
 after thorough  discussion with all pertinent program  elements  in the
 Regional Office and with the affected State and  local  control  agencies.
*Thus "technology forcing" based upon reasonable (not crystal ball) projec-
  tions should be required wherever necessary to attain and maintain the
  primary standards.

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      The  Agency  must  exercise  good judgment  in  determining whether the



 control strategy portion  of  an  approved SIP  is  inadequate to achieve



 national  standards  on   a  timely basis.  It is the Agency's policy to



 request such  plan revisions  only where they  are clearly necessary.  To



 declare that  a SIP  is  substantially  inadequate  will  imply a need for



 new  and more  stringent emission limitations.  It will  take some time  to



 develop such  limitations.  Pollution  sources might use this situation



 to resist coming into  compliance with existing  regulations and thus,



 ongoing abatement actions  could be inhibited.   Further, frequent revisions,



 particularly  where  they affect  emission control  requirements, are unde-



 sirable in  that  they  confront  source  owners  with a "moving target".



     Another factor to be  considered  is that  any plan revision submitted



by a  State that  changes some  part  of  the SIP  or  which adds a new part



could result in  a Section  307 challenge by the affected sources to the



changed or added  part.   Such  action may'del ay enforcement of the new




requirements.  (Section 307 provides  for a process  of judicial  review of



the Agency's action in approving or promulgating any implementation



plan  or revision  thereof.)  The Office of Enforcement's experience



with  §307 suits  indicates that substantial delays in enforcement can



result from such  challenges.   Therefore,  this reason alone is  good



cause to minimize changes in regulations  in the   plan until  present con-



trol   requirements are  fully implemented and any   revision  is  clearly



necessary.



      This guideline addresses the procedures to  be followed in determining



those areas that  mav not attain national  standards (i.e.,  both Air



Quality Maintenance Areas (AQMA's) and non-AQMA's).  Once it has been



determined  that  a SIP  is  substantially inadequate, the degree of analysis

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needed by the State to demonstrate  attainment and  maintenance  varies  depen-
ding upon whether the area is designated an AQMA or not.   The  analysis
procedures for AQMA development are found in Part  51, Subpart  D  (Main-
tenance Regulations).  These Maintenance Regulations will allow the
Regional Administrator to modify certain analysis  requirements by follow-
ing specified procedures.  Procedures for States to demonstrate attainment
in non-AQMA areas are those existing Part 51 regulations on SIP
development.
     This guideline  does not address procedures for areas where only
a maintenance plan (i.e., no attainment plan necessary) is needed.
Procedures for such  maintenance plans are found in Part 51, Subpart D
(Maintenance Regulations).   It should be noted that calls for SIP
revisions where only a maintenance- plan is  needed  (i.e., where no
attainment plan is needed) need not be accomplished by July,  1976.
The  Regional Administrator may schedule the  call for a maintenance plan
at any  time  for those areas  that do not have an attainment problem but
which may need a maintenance plan.
     This guideline sets forth  (1)  the  responsibilities  of headquarters
and Regional  Office personnel in relation to determining the  need for
and calling for plan revisions, (2) the procedures for  determining when
a plan revision to the control  strategy portion of the  SIP is  necessary,
and (3) the procedures for notifying the State that a plan revision is
necessary.  EPA procedures for approving/disapproving SIP revisions
submitted by States are not included in this Guideline  but are contained
within OAQPS Guideline 1.2-005A (as revised).

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           RESPONSIBILITIES  CONCERNING PLAN REVISIONS





A.  REGIONAL OFFICES



     The Regional Office is responsible for reviewing available infor-



mation to determine if the approved control strategy is substantially



inadequate to attain and maintain the national  standards.   In making



this determination, it is important that the various program elements



within the Regional Office (OAHM, S&A, OE) be involved in  the evalu-



ation and decision-making process.   The various activities



required to determine the adequacy of the approved SIP generally involve



the responsibilities of these three Divisions.   For example, the analysis



to determine the inadequacy of the SIP requires (1) a determination of



the validity and representativeness of the ambient air quality data



(S&A activity), (2) a determination of which portions of the control strategy



need to be revised and what new regulations should be recommended (OAHM



activity), and (3) a determination of the impact of these  recommended regu-



lations on on-going enforcement activities (OE  activity).   Interdivisional



coordination is therefore essential to make the most effective call for



plan revision.  Similarly, coordination, as appropriate, with State and



local  agencies can also result in a more effective plan revision.



     Specific Regional Office responsibilities  require that each SIP



for each pollutant (i.e., particulate matter, sulfur dioxide, carbon



monoxide, photochemical oxidants and nitrogen dioxide) be  reviewed  during



Fiscal Year 76 to determine if any such SIP is  substantially inadequate



to attain and maintain national standards.  In  cases where the SIP  is



determined to be substantially inadequate, the  Regional Office must:

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     (1)  By July 1, 1976, notify the State, and announce in the Federal

Register that the control  regulations contained in the SIP for the

pollutant in question are  inadequate to attain (and in most cases to

maintain) national  standards and that a plan revision is necessary.   A

call to the State for a plan revision should be as specific as possible

in suggesting what new or  revised regulations are needed.  Further,  the

call for plan revision should establish a time schedule for the State to

submit an indication of its intent to develop the necessary plan revision

and also for the submittal of the actual  plan revision.  (See Chapter IV

for additional details.)

     (2)  By July 1, 1977, the State must submit a plan revision that

includes, to the extent needed to meet national primary standards, all

emission limitations which it is reasonable to anticipate will be achievable

within  a reasonable  period of time.  Also, any other control measures

(generally  referring to transportation controls and land use measures)

necessary for attainment  and maintenance must be submitted by the

State by July 1, 1978.

      On October 15, 1973, the Administrator delegated his  authority to

 request plan revisions from States  to  the  Regional  Administrators through

 EPA Order 1270.5 (see Appendix  C).   In cases  where a plan  revision  is

 requested by The Regional Office,  the  Assistant Administrators  for  OAWM

 and OE should be notified.*
 *NOTE:  It has been recommended that EPA Order 1270.5 be amended  to  read
  as indicated.  Presently the order requi res the RO's to obtain the  concur-
  rence of the AA's on significant plan revisions.  The order also presently
  states that concurrence should be obtained on other plan revisions.

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     Once the plan revision has been submitted by the State, the Regional
Office is further responsible to review, to recommend approval/disapproval
and promulgation and to prepare the Federal Register package associated
with any measures which have been determined to be necessary to assure
that the national standards will be achieved.  These procedures are
contained in the July 22, 1975 Strelow/Legro memo to all Regional Adminis-
trators and will be incorporated in OAQPS Guideline 1.2-005A for proces-
sing  SIP revisions.
B.  HEADQUARTERS (OAWM/OAQPS/OTLUP  AND  OE/DSSE/MSED)
      OAWM/OAQPS/OTLUP will  provide  policy  and  technical  assistance  to  the
Regions  concerning  the  plan revision  issue.  OAQPS  has  prepared  various
policy guidelines  concerning operational procedures  and the  criteria
to  be considered in calling for plan  revisions.   Various  technical
documents  are  also  available to assist  in  the  analysis  of the  adequacy
of  the existing control  strategy.   For  example,  many of the  technical
guidelines  prepared primarily  for the development of maintenance
plans such  as  Volume 11  and Volume  12 dealing  with  data analysis
and modeling respectively  can  be of value  when considering plan
revisions  for  the  attainment and maintenance of  national  standards.
In  addition, guidance  on control regulations and "cookbook"  type manuals
that  provide step-by-step  guidance  on the  development of  approvable SIP's
for NO  and Ov  will  be  provided during  the Fiscal Year.   Further, OAQPS
       A      A
will  provide additional  assistance  as appropriate to the  Regions in the
plan  revision   area.

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     The Office of Transportation and Land Use Policy (OTLUP)  is
a staff office of OAWM which provides technical  support to the Regional
Offices in the development, evaluation and promulgation of transporta-
tion and land use related SIP actions.  As such, OTLUP will  provide
policy guidance to the Agency on land use and transportation measures
(see August 5, 1975,  DRAFT policy memo  on  subject) and will participate  in
the review of such control  strategies being implemented by the Regions
as outlined in OAQPS Guildeline No.  1.2-005A (Revised)

      The  Office  of  Enforcement  (DSSE  and MSED)  will  provide appropriate
 assistance  to  the Regions  regarding enforcement policy with respect  to
 stationary  sources  and  transportation control plan elements,  respectively.

      C.  ALTERNATE  RESPONSIBILITIES
      The responsibilities  within the  Agency are  somewhat different in
 those  cases where plan  revisions are  necessary  to take account of new
 or revised  national standards.   In this case, OAWM has the primary
 responsibility of preparing and  publishing in the Federal Register

 (1) the new or revised  national  standards and (2) specific guidelines
 on what actions  States  need to take to  develop,  adopt and submit an
 approvable  plan  to  implement the new  or revised  standard.  In general,
 all States  will  be  required to submit a plan for a new national stan-
 dard  or will  be  required to augment and/or revise their existing SIP's
 to consider a  revised national standard.  After  OAWM  has published
 guidelines  for the  development of approvable SIP's,  the Regional Offices
 are then  responsible  to assist States in the development of SIP's, to
 develop plans  where States fail, etc.
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     In situations where the SIP regulations (40 CFR Part 51)  are modi-
fied in such a way as to affect the control  strategy requirements (such
as the action in relation to maintenance of standards,  40 CFR  51.12,
June 18, 1973) OAWM and Regional Office responsibilities are identical
to those described for a new or revised standard.

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        III.  PROCEDURES FOR DETERMINING WHETHER A SIP/CONTROL
                     STRATEGY NEEDS TO BE REVISED

A.  IDENTIFICATION OF PROBLEM AIR QUALITY CONTROL REGIONS
    It is difficult to develop comprehensive guidelines for all  cases
on exactly how to determine whether a control strategy will need to be
revised.  While there may be a few situations where it is obvious that
a plan revision is necessary, in general it will be a difficult task to
determine that a plan is substantially inadequate to attain national
standards.  The basic problem is to determine whether AQCR's are pro-
gressing satisfactorily toward attainment of national standards
as sources  come into compliance with emission limitations contained
within  the  SIP.
     Some factors that could be considered in making a determination as
 to whether  a  SIP  is  substantially  inadequate are as follows:
      1.   Factors  favoring  a  finding  that the SIP is not substantially
          inadequate:
        a.  Available data provide a reasonable expectation that
        NAAQS have been or will be achieved by the currently approved
        SIP under provisions of the existing control strategy.
        b.  The most recent  air quality data are below or not far
        above NAAQS.
        c.  Much abatement work is ongoing or yet to be completed
        under existing regulations.
        d.  Air quality and  emission data are not yet extensive  in
        terms of  time and  geographical  coverage.
        e.  Air quality  levels  have  varied erratically up  and down
        in  recent years and  a clear  trend is not yet determinable.
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     f.  Emission control  regulations  have  been  made  more  stringent



     or more compehensive  in the past  1  to  3  years  but  are not yet fully



     implemented.



     g.   Existing regulations  are  very  stringent  --  at or border-



     ing on a requirement  that  all  reasonable control measures  thet  can be



     achievable arc being used.



     h.   Major reductions in emissions  have  been  made  in  the past



     year or two and perhaps more reductions  are programmed for  the



     near future.



     i.   The governmental air  pollution control program has grown



     substantially in  the  past  few  (1  to 3) years  and enforcement



     actions are being intensified.






2.    Factors favoring  a finding that  the SIP  is  substantially  inadequate:



     a.   There is good evidence that  compliance with existing



     regulations will  not  result in achieving NAAQS by  the existing



     attainment date.



     b.   Recent air quality levels are  substantially above NAAQS.



     c.   Most existing regulations have been fully implemented;



     future improvement in air  quality under  existing regulations



     will  not be substantial.



     d.   Air quality  levels over the  past  few years  show  an evident



     trend which,  in consideration of  abatement  yet to  occur, shows



     clearly that NAAQS will not be attained  by  existing control



     measures.
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         e.   Air quality and emission data are generally accurate
         and extensive as to time series and geographic coverage.
         f.   Emission control  regulations have not changed greatly
         in recent years.
         g.   Existing regulations are not particularly stringent
         and do not include all emission limitations which it is reasonable
         to anticipate will be achievable within a reasonable period of time.
         h.   There has not been much change in air quality over the
         past 1 to 3 years (and levels are above NAAQS).
         i.   Governmental control activities have been reasonably
         adequate for the past few years (1 to 3) and regulations are
         probably enforced well.
     Of course, a number of factors other than air qualtiy and emission
data must be considered in the  determination of the need fp_r  a plan
revision, and/or the tining of  the call  for plan revision.  These  factors
include the following:
     1.  The Clean Air Act requires that SIP's which are substantial1y
inadequate to attain national  standards  be revised.  Simply because
ambient air quality data exceed a national  standard by 10% or 15%  does
not in itself indicate an immediate need for a plan revision.   Clearly,
the normal variation of ambient air quality due to meteorological  condi-
tions, etc., may cause such a condition  to exist.  The requirement of
substantially  inadequate  provides the Regional Office with flexibility
in assessing the need for, and especially the timing of a call for plan
revision.

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     2.   The Agency has submitted to Congress a number of amendments
to the Clean Air Act.   The most pertinent amendments  affecting  the  call
for plan revisions involve:
          (a)  The TSP Act Amendment,  and
          (b)  The Transportation Control  Plan Act Amendment.
     These  two amendments are very similar and if accepted by Congress,
it is anticipated that they would provide extensions to attain the
national standards and provide guidance with respect to those areas
where unreasonable controls are needed to attain standards.  Additionally,
the Senate  is considering a new Section 120 to the Clean Air Act which
would require the establishment of a planning organization in any area
where SIP's  are  inadequate to attain and maintain NAAQS.  Since these
amendments  are presently  being discussed by the Congress, calls for
plan  revisions should be  postponed until after the amendments are
fully considered  and  adopted by  the Congress.  It is presently estimated
that  the revised  amendments may be available toward the latter part of
1975.   (NOTE:  It is  recommended that calls for plan revision be post-
poned,  however the analysis necessary to determine the extent of the
problem should proceed.)
      3.  In some  cases,  little or no ambient  air quality data exist
to allow for a determination of  the adequacy  of the SIP.  For example,
in many cases, nitrogen  dioxide  data may not be available due to the
controversy concerning the original reference method.  While adequate
and sufficient data should exist in many major urban areas  (due to  the
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special field projects over the past few years) there may be some areas



where sufficient data are not available.  In these cases, any decision on



attainment and the need for plan revis ions..may have to be delayed from



the Fiscal Year 76 time period.




 B.   Review of Specific Conditions  within  Individual  AQCR's



      To attain national  standards, EPA  policy is  that air quality  levels



 throughout an AQCR must be equal  to or  below  (i.e.,  better  than) national



 standards (see OAQPS Guideline Document 1.2-008,  Revised August  22,  1974).



 In  many cases, much of an AQCR may have ambient air  quality at or  below



 the national standards, however,  a few  sites  may have air quality  that



 is  above the national standards.   A review  of the specific  conditions that



 cause these high ambient concentrations on  a  site-by-site basis  will  allow



 the Agency (a) to determine if a  pl-an revision is necessary, and (b)  to



 call  for plan revisions that address localized problem areas.  Control



 strategy revisions based on site-by-site reviews may not be possible in



 many large urban areas, especially for  particulate matter,  where non-



 attainment of standards may be a  relatively widespread problem with  perhaps



 more than 50% of the monitoring sites above the national standard.  In



 these cases, it is more appropriate to  review the entire control strategy



 for the area (i.e., AQCR, county or some other geographic area).  It is



 suggested, however, that even in  such urban areas each  site be



 examined to determine the quality of data being collected and to determine



 if local sources  excessively  bias  ambient measurements.




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     Prior to the review of the adequacy of the control  strategy, it



is important to investigate the available ambient air quality to deter-



mine (1) its validity and (2) its representativeness (i.e., what does



the data represent and how should such data be used as the basis for



requiring a plan revision?).




     1.  Evaluation of Data



     The validity of  the air quality  data is a major  item in the review



of potential problem  sites.  Monitoring and Data Analysis Division, OAQPS,



has prepared several  guidelines  to assist in the certification and inter-



pretation of air quality data  (See Appendix B).



     While  EPA should generally  be confident of the validity of the air



quality data submitted by State  and local agencies, it is also necessary



to review the validity of specific data, especially those data which



indicate the need for a plan revision.  The National Air Data Branch (NAD3)



periodically questions State and local agencies concerning aoparent data



anomalies via a form  letter; however, a more thorough investigation of the



ambient data which indicates a problem would be conducted by the Regional



Office.  The Regional Office should refer to the guidelines mentioned above



for the specific items that should be reviewed to assure valid data.



Briefly, the review should determine:



            (a)  Are the proper numbers and kinds of monitoring equipment



                operating in the area?



            (b)  Are monitoring sites  properly located in accordance with



                published guidelines?



            (c)  Are they properly calibrated and properly operated?



            (d)  Are the collected data properly validated?






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          (e)   Have all  abnormal  values  been checked?
          (f)   Have peak concentrations  which are  of most  concern  been
               evaluated to  determine  their accuracy?
          (g)   Are the data  accurate  and valid and can  they  withstand a
               legal  challenge of their  validity?
     In cases  where data are questionable,  they should  generally not be
used in control strategy development.   It is anticipated that many Section
307 challenges will be filed in relation to revised SIP's.   Therefore,  it
is prudent to  base the need  for plan  revisions on  valid and  defensible
data.
      If it is  determined that the air quality values are valid, then a
further review of  the data should be made to determine if the data are
representative and if such data should serve as the basis of a revised
control strategy.  The  review of the data should  attempt to determine
if  a  nearby source(s) overly impacts on a monitoring site.
      The  purpose  of determining the "representativeness" of the data is
so  that the control regulations that will be adopted will affect the
sources that  cause high ambient concentrations.   For example, if an
ambient monitor is overly influenced by street dust, it is improbable
that  new  control  regulations which olace stringent  requirements on
stationary sources will have  a beneficial impact  on the ambient levels
at  the site.   Similarly, requiring particulate matter  control on fuel
combustion sources may  not provide for  attainment where recorded ambient
levels in excess  of national  standards  are  due to windblown fugitive dust.
It  is recommended, therefore, that each site be examined to determine
its "representativeness" for  use  in the development of a general control
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strategy, and/or to determine the sources which the site does  represent.
If a site is source oriented, the data collected at that site  should be
used to determine the degree of control  that source may need to attain
standards but should not be used as the  basis for control  regulations
for all sources with the AQCR.
     In examining the representativeness of the data,  it may be determined
that unusual conditions existed such that the data should not  be used in
control strategy development.  For example, if the frequency and duration
of inversions and stagnations were unusually high, air quality levels could
be higher than normal.   Unusually warm or cold weather will  result in a
change in fuel use which may increase ambient levels above normal.   If
conditions  conducive to higher pollution levels were so unusual as to
not be expected to occur again for many years (e.g., 5 or 10 years), it
may be appropriate to discount high pollution levels occuring during such
rare events.  Other examples of unusual  events include dust storms, fires
or unusual  control equipment malfunction or shut-down which could tempor-
arily cause abnormally high ambient concentrations.  Generally, data
collected during such situations should not be_ used as_ a_ basis for requir-
ing  additional  control  erf stationary sources.
     In the investigation of air quality data, the Regional  Offices
should obtain the very latest air quality concentrations for the s_jte_ ir\_
question.   It may be necessary to obtain these data from the State or
local agency if they are not included in SAROAD.  (In these cases, the
new data should be submitted to SAROAD to assure the availability of
the latest data to all  users.)  The data used for the review of the
adequacy of the SIP need not be for a calendar year, but should represent
the most recent 12 months (or four quarters) for which data are available.

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While OAQPS Guideline 1.2-008 points  out that compliance  with  annual
NAAQS shall be based upon calendar year data, it further  points  out
that a continued appraisal of air quality on  a quarterly  basis is
needed to assess the status and progress with respect to  the  adequacy
of the SIP.  Hence, it is not inconsistent with other Guidelines to
use non-calendar ambient data to determine if a SIP is inadequate
to attain standards.
2.   Analysis of Control Strategy
     With the addition of the latest air quality data, a  comparison of the
trends in air quality levels at the site in question with the  air quality
trends noted at other sites within the Region (State, city or  other areas
where comparable results should exist) should be made.  If the increase
or decrease is significantly different from that at the other  sites,  it
would appear that a localized problem exists.
     For the purposes of this guideline, consider three hypothetical
cases:
     Case 1:  Assume that one site is above the national  standards  in  an
AQCR.  In this case, it is recommended that a review of the emission  data
and compliance status of sources within the immediate vicinity of
the site in question (sav within a 1  to 3 mile radius--particulate
matter, sulfur dioxide, and CO; oxidant would require a much  larger
area) be made.  Points to consider include:
     (a)  Are all sources, both point and area sources, included in
     the inventory?
     (b)  Are some  sources presently uncontrolled?  If so, are there con-
     trol  regulations with which  these sources must ultimately comply?
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     If not, do these sources impact sufficiently on the site to warrant



     a recommendation for a plan revision to require further emission



     limitations on these sources?



     (c)  If the sources reviewed in (a) have applicable regulations that



     they must adhere to at some later date, is the anticipated emission



     reduction adequate to reduce ambient levels to below the standard?



     (d)  Do the sources reviewed in (a) have applicable emission limi-



     tations they must presently comply with?  Are the sources in compli-



     ance with the regulations?  If so, will additional emission reductions



     be needed to provide for the attainment of the national standard?  If



     the sources are not in compliance with the emission limitation, is the



     source on a compliance schedule?  Should EPA/State enforcement action



     be initiated against the source?




     (e) Have the source emissions in the vicinity of the site in ques-



     tion increased significantly?  Is a plan revision necessary to com-



     pensate for increases in emissions?  What action is needed in relation



     to assuring that the State adequately considers ambient standards



     prior to approval  for  construction  of  new, sources?




     Case 2:   Suppose the attainment date for an AQCR has  passed.   If the



air quality data are found to be above the NAAQS,  it would seem at first to



indicate that the SIP needs  revision.   However, the Regional Office should



consider some other items prior to requesting a revision:



     a.   Are all  affected sources in compliance with the SIP?




     b.   Has sufficient time elapsed for recent emission  reductions  to



     be reilecteci in the air qualtiy data?
                                 19

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     c.   Have any of the  sources  affecting  the  site  received  a variance

     from the State?  Was such  a  variance legal?   If not,  is  enforcement

     action necessary?

     d.   Are new sources  affecting  the  site?   Is  the State giving  proper

     consideration to the NAAQS when  approving  new sources?

     e.   Should EPA action be  taken to  implement  new source review

     procedures?

     Case 3:  Suppose that an  AQCR  was  originally classified  Priority  III

because no data were available  to indicate  if any problems existed.  More

recent data however show  that  an  air  quality  problem does  exist.   What action

should be taken?*

       In this case, the  regulatory structure of  the  SIP should

 be reviewed since the SIP may  contain  emission control  regulations ade-

 quate to attain NAAQS.   Though the AQCR was  classified  Priority III,  the

 example region approach  may have been  used for plan  development resulting

 in the adoption of State-wide  regulations.  The  implementation of these

 regulations may be adequate to attain  NAAQS.
 *NOTE:   In  the Draft of this Guideline that was circulated for review in
 August,  1975, a  discussion was provided which indicated that the AQCR iden-
 tified  above should be reclassified to indicate that an air quality problem
 existed.  Many commentors correctly noted that this  was contrary to pre-
 vious guidance on the recommended use of the Priority Classification System
 (8/12 memo  from  Mr. Steigerwald to Mr. Holman, Region I).  Since that memo,
 additional  discussions have lead to the belief that the Priority Classifi-
 cation  Scheme is useful and should be retained.  Consequently, work is
 underway to improve the classification system (e.g., to delete regulatory
 requirements associated with it and to revise it to indicate current
 Agency  priorities).  Additional information will be provided to the Regional
 Offices  for review and comment prior to finalization of a modernized  classi-
  fication scneme.
                              20

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3.    Available Analytical  Techniques-1

     Predictions of future air quality,  especially when  abatement  actions

are still  going on or to be taken,  are not precise.   Therefore,  any finding

on what future air quality will be is  not precise and a finding that a SIP

is substantially inadequate at this time should consider a number of variables

rather than be based on simplistic calculations.   Various analytical tech-

niques are available to assess the source/receptor relationship, and the ef-

fect of emission control limitations on this relationship.  Some of these

techniques are described below:

a.   Abbreviated Roll-back Procedure

     This procedure is useful  when the amount of additional emission reduc-

tion expected between the present time and completion of actions to assure

compliance with all existing regulations can be readily calculated, such as

when only a few sources remain out .of compliance.  In using this procedure,

the following calculations are made:

     (1)   Prepare an estimate of the emission reductions that will occur

     because of completion of remaining abatement actions.  For example,

     25 sources may remain out of compliance.  Their present emissions

     are 140 tons per day.  When controlled in accordance with existing

     regulations, their emissions will total 40 tons per day (100 tons

     not yet controlled).

     (2)   Prepare  an  estimate  of  total emissions  in  the area as of

     the present time,  either  by:

          (a)   Updating  the on-going emission  inventory,  or
 *Though not discussed  in  detail  herein,  it  is  assumed  that  a  current
 emission inventory for point  and non-point  source  and  source  compliance
 information is  available.   Point sources  are  generally defined  as  those
 sources with a  potential  for  emitting 100 tons or  more of a criteria
 pollutant.


                                 21

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     (b)   Taking the original  SIP  estimate  of emissions  after  the

     control  strategy is  implemented and add to  it the  "not yet

     controlled" value from Step 1.   For example say  that  present

     emissions are 1000 tons per day.

(3)  Estimate future air quality after remaining abatement is

accomplished  by use of the proportional  model, using  the following

formul a:

  Future  AQ _  Present emissions - emissions yet to be  controlled
 Present  AQ                      Present emissions

assume present air quality is  90  ug/m

  Future  AQ  =  1000 - 100
     90 ug/m3      1000

Future air quality = 81 ug/m3

If the pollutant of concern involves a background (rural area) factor,

it must be considered.  For example, assume the  pollutant  is particu-

late matter and background  levels are 30.   Future air quality is then

calculated, in this example, to be:

  Future  AQ - Background   =  1000 - 100
  Present AQ  - Background        1000

  Future  AQ - 30  _   900
      90-30 ug/m3    1000

  Future  air quality = 84 ug/m3

Such a procedure is useful in  that it considers  current air quality,

emission  and compliance information to assess the potential of future

emission  reductions.  However, other more sophisticated techniques  are

available to relate emissions  to air quality.  It is  generally recom-

mended that in determining the need for a plan revision a  more detailed

approach  be utilized in defining the relationship between  emission

reductions and air quality.

                               22

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b.  Modified Rollback



     The modified rollback model represents an improved form of the



basic rollback model and allows for direct consideration of additional



parameters not considered by the basic rollback model.  The modified



rollback models can be used manually or by computer depending on the



complexity of the study area.  They are available in four basic forms



which are progressively more detailed and accurate and progressively



require a more extensive data base and computation time.



     The first form of the modified rollback models extends the basic



rollback to multiple categories of sources, which may experience differ-



ing rates of growth and degrees of control.  The second modified form



extends this multiple-source version to include the effects of average



stack heights for the various categories.  The third model  includes the



radial distance from source to receptor, and the fourth model  adds wind



direction frequency.  The technique is described in a paper entitled



"Rollback Modeling - Basic and Modified" by Noel de Nevers  and Roger



Morris, and is further summarized in Volume 12 of the Maintenance Guide-



line Series:  Applying Atmospheric Simulation Models to Air Quality



Maintenance Areas.



c.  Diffusion Modeling



     This is the preferred predictive tool  available in relating emissions



to air quality data.  A number of diffusion models, Air Quality Display



Model (AQDM), the Implementation Planning Program (IPP), etc., are avail-



able for defining urban situations on an annual basis and are listed in



Table 1  (see OAQPS  Guideline Document No. 1.2-031, September 1974 for



detailed discussion).   Diffusion models such as these, as well as technical
                                 23

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                                                      Table 1
                                     Summary of Simulation Model Characteristics
Model
Name
Rollback
Appendix J
Miner-
Hoi worth
Hanna-
Gifford
Hanna-
Glfford
Pollutant
Specifi-
cation
Any
°x
SO, JSP
2
SO-.TSP
CO2

SO,.TSP
Averaging
Time
Specifl- Emission
cation Data
Any
1 Hour
1 Hour,
Annual
Annual


1-24 Hour
1
1

1

1

2
Meteor-
ological
D.Ha
1
1

3

2

5
Concen-
tration.
Estimates
3
3

3

3
,
2
Ease of
Use
1
1

1

1

2
Avail-
ability
1
1

1

1

1
Rell-
ab1 1 1 ty
3
3

1

1

1
Applicability
to AQM
3
3

3

3

2
w. Point Source
model
w. HIWAY
AQDM
SCIM*
APRAC-1A
SAI*
SJ,,TSP
co2
S02,TSP
SJj.TSP
CO
CO,N02,0X
1-24 Hour
1-24 Hour
Annual
1-24 Hour
1-24 Hour
1-10 Hour
3
3
3
3
3
2
5
5
4
5
5
5
1
1
1
1
1
2
2
2
3
3
3
3
2
2
2
3
2
3
1
1
1
2
2
. 2
1
1
1
1
1
2
*lhese models are currently 1n a developmental  and debugging  phase;  they  are  not available for general
 distribution as computer programs.
                                                     Key to Table 1
                                rn, nx. NO,)
A.  Pollutant Specification
    Any pollutant
    Specific Pollutants (sii,
B.  Averaging-time Specification
    Any averaging-time
    Annual Average
    1  to 24  hour  Average
C.  Emission Data
    1.  Area-wide Emissions Total
    2.  Total emission distributed as finite area  sources
    3.  Detailed point, line and area sources
D.  Meteorological Data
    1.  None
    2.  Average wind speed
    ^t  Average wind speed and mixing height
  «.  »'•  Frequency distribution of wind direction,  wind  speed,
        stability and mixing height
    5.  Hourly variations of wind direction, wind  speed,  stability'
        and mixing height
                                                       24
                                                              H.
Concentration Estimates
1.  Estimates at any specified point
2.  One estimate for each area source grid
3.  One estimate applicable to entire AQMA
Ease of Use
1.  Slide-rule
2.  Snail computer effort
3.  Major computer effort
Availability
1.  r'~n literature
2.  National Technical Information Service
3.  EPA, upon request
Reliability
1.  Can be verified and calibrated
2.  Verification 1s Incomplete, possibility of calibration
    1s uncertain
3.  Questionable, acceptable for crude estimates only
Applicability to AQM
1.  Can distinguish between specific source and land use types
2.  Can distinguish between land use types only
3.  Considers no distinction between sources or land uses

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assistance to operate them on the EPA UNIVAC 1110 system is available

from MDAD, OAQPS.   Point source models are also available for single

source short-term (1-hr and 24-hr) situations.   Diffusion modeling

requires detailed emission, air quality and meteorological data to

mathematically simulate the emission/air quality relationship for a

given AQCR.  While there are certain limitations which restrict the

use of diffusion models (lack of data, severe topographic variations,

etc.), the method does provide the best available approach to predict

resulting ambient levels caused by the application of emission limita-

tions on emission sources.  (See note)

C,   Determination for  Need for  Plan  Revision

      During  the technical  analysis to determine  if a plan  revision  is

appropriate, the Regional  Office  should consider the impact  of calling

for  a plan revision  in relation to ongoing  enforcement programs.  The

possibility  of a Section 307 challenge, and its effect on  compliance

and enforcement should be discussed  and considered.  While plan revi-

sions should be sought where determined necessary, attempts  should  be

made where possible  to minimize the  impact  of plan revisions on enforce-

ment activities.
 NOTE:   Both  rollback  and  diffusion modeling  techniques  have been
 discussed  in  this  document.   It should be noted that the Agency
 proposed in  the  Federal Register^ on September  14, 1973, that future
 control strategy development  shall be based  upon diffusion modeling
 analysis.  This position  may  be somewhat modified prior to promulgation.
 Further, additional guidance  on modeling techniques Will be published in
 Appendix A,  of the Part 51 regulations.  For purposes of preliminary
 analysis of  the problem AQCR's, rollback techniques may be used; however,
 when the revised control  strategy is developed by either the State or
 EPA it  is  strongly recommended that diffusion modeling be utilized
 in most cases. In  other words, rollback is adequate for the decision
 to call for  a plan revision but is not as good as diffusion modeling
 as the  basis  of costly regulations that can  be challenged under Section 307.
                                   25

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             IV.   PROCEDURES FOR REQUIRING PLAN REVISIONS



     If the analysis of the problem indicates that a revision  to the



control strategy is needed, the following actions are necessary:





A.  PLAN REVISION DOCUMENTATION



     The Regional Office should document the reason why the  plan revision



is necessary, providing a reasonable amount of detail on the discovery



analysis performed to determine the need for the revision.   To the ex-



tent practical, the Regional Office should suggest  specific source(s)



or source categories or regulations which should be considered under the



plan revision.   While it is hoped that the approved SIP will be adequate



to attain the national standard on an AQCR-wide basis, it is likely that



portions of  some AQCR's will need  further controls to achieve



the standards.   In other AQCR's, area-wide changes in the SIP will



be needed.   Recommendations for SIP  revisions should therefore be made as



to the specific geographic area in which the revision is needed, i.e.,



by AQCR, by county, by "hot spot" areas or in some definable area where



an air quality problem has been noted.



     The analysis which is performed to determine the need for a plan re-



vision should be discussed with appropriate State and local  officials.



Similarly, the particular regulations which should be revised  or added



should be identified, to the extent practicable at this stage  of evalu-



ation, with appropriate State and local officials.




B.  NOTIFICATION OF STATE AND PUBLIC



     The Regional Offices should first confer with the State and/or local



agencies involved and advise them of the need for plan revision and explore



with them, any particular regulations which clearly need revision or






                                 26

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need to be added and those which do not.   Subsequently,  the Regional  Admin-



istrator should officially notify the State that a revision is necessary



via a letter to the Governor followed by  a Federal Register notice.





1.  Federal Register Notice



     Various Federal Register actions will need to be taken in relation to



advising the State and the public that the Agency has determined that a



plan revision is necessary.  The first Federal  Register  action involves



a Federal Register notice indicating EPA's determination of an SIP defici-



ency and requesting corrective action on  the part of the State agency.



     The Federal Register notice can be considered as an "open letter"  to



the State and it should contain a summary of the detailed analysis on which



the need for the plan revision is based.   Specifically,  the notice should



discuss the following:




a.  Specific reasons why the plan revision is necessary;



b.  Recommendations as to the actions which appear to be necessary



to correct the deficiency, if known, e.g., what sources  appear to cause



the need for further controls; what regulations, if any, should probably



be revised or added; and which regulations appear to be  adequate.



c.  The Federal Register Notice should also indicate that the plan



revision should include the degree of emission reduction necessary



to offset emission increases that can reasonably be expected to result



from projected growth of population, industrial activity, motor



vehicle traffic and other factors that may cause or contribute to



increases in emissions;  (NOTE:   In non-AQMA areas, it is not necessary



to require the detailed consideration of  growth as is required for

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AQMA's.  In non-AQMA's, the FMVCP, NSPS, and the review of new  source

procedures should generally be adequate to maintain  NAAQS.   However,

the plan revision should consider growth in an area  and, where  necessary,

include the degree of emission control  to provide for continued main-

tenance of NAAQS.)

d.  The Federal Register Notice should identify the  specific geographic

area within an AQCR where the problem exists.

e.  If the non-attainment area is an AQMA, the Federal  Register Notice

should inform the State that the plan revision for attainment and main-

tenance should be developed and submitted in accordance with procedures

set forth in Subparts A, B, and D and other EPA guidance, and should

provide a schedule under which the full  attainment and  maintenance plan

must be submitted.*

f.  The other  portions of the SIP which may need to be revised as a conse-

quence of the  control strategy revision.  These may include portions

required under the following sections of 40 CFR 51:

      (i)  Section 51.11  Legal Authority—especially if transportation

      or land use  controls are deemed necessary.

      (ii)  Section 51.15  Compliance Schedules--must be provided if new

      control regulations are adopted.

      (iii)  Section  51.17  Air Quality Surveillance--if the Region has a

      substantial  air quality problem, more ambient sampling may be required

      to define the extent of the problem and monitor progress.
 *The  final 40 CFR 51 regulations for maintenance plan for areas that need
 to  submit  a  plan to attain national standards may specify a constraint
 on  the  length of this schedule  (such as July, "1978).
                                28

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(iv)  Section 51.21  Intergovernmental Cooperation—portions may
need to be revised if the State delegates new responsibility to
other State or local agencies to carry out portions of the plan.
(v)  Section 51.20 Resources—new control regulations may require
additional resources for enforcement purposes.  Such information
should be reported with the plan revision.
(vi)  Section 51.10 General Requirements—the control regulations
submitted as part of the plan revision will  probably indicate the
need for a change in the date of attainment of the national
standards.  The notice should specify that the revision must provide
for the attainment of the primary standards "as expeditiously as
practicable."  Until the Clean Air Act is amended to provide
for extensions of the deadlines, the mid-77 attainment date  is
still technically the "no later than" cut-off point of the Act for most
areas.  [A one-year deferral mechanism (i.e., Section 110(f)) exists for
source specific extension cases.  However, OE advises that use of such a
mechanism, because of the requirements of adjudicatory hearings, can be
time consuming and should probably be minimized.]
     For those few areas with pre-1977 attainment dates in which it
is reasonably certain that a control strategy can be developed which
could attain the standards by mid-1977, the state should be  required
to submit revisions which will attain the standards "as expeditiously
as practicable," but no later than mid-1977.   The state should be told
that it will be necessary to apply formally for a deadline extension
of the original attainment date (e.g., May,  1975) pursuant to Section

                                29

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110(e) and 40 CFR 51.30.   If these requirements are otherwise met,  an
extension can be granted  if the revised plan  requires  significantly
more stringent controls than contained within the original  SIP.
     For most areas it will be impossible to  identify  an  appropriate
attainment date in the notice because, although the analysis  supporting
the notice must identify  the nature and extent of the  problem,  an  appro-
priate attainment date will not be identifiable until  the control  strategy
is developed.  For these  cases, the notice should require the State to
identify a new attainment date, which must be "as expeditiously as  practi-
cable", and submit it for approval with the plan revision.   (It should
be noted  that this is an interim policy until the Act is amended  to
provide new attainment deadlines and/or extension procedures.)
g.  The notice should specify the date for submission  of  the  revision.
Section 51.6(b), Revision, states that "the plan shall  be revised  within
60 days following notification by the Administrator, or by such later date
prescribed by the Administrator after consultation with the State." Since
a control strategy will need to be developed, compliance  schedules  deter-
mined and negotiated with regulations subjected to a public hearing and
adoption, it appears that six months or more  may be needed to revise  the
control strategy portion of the plan.
     The Agency has established firm end dates for the submittal of plan
revisions by States to attain national standards.  Plan revisions, containing
emission linitations,  shall be submitted by July 1, 1977.  In cases where
additional measures are necessary (e.g., land use and transportation controls)

                                      30

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such measures may be submitted no later than July 1,  1978.   It should be



noted that these are "no-later-than" dates and that plan revisions should



be submitted as expeditiously as practicable.  (NOTE:   No firm end dates



exist for areas that need only maintenance plans.  The schedule for the



development and submittal of such plans is to be established by the Regional



Administrators.)



h.  The Federal Register Notice should also request that the Governor of



the State advise EPA within 60 days of its intention  to comply with



the request for a plan revision and to set forth a timetable for starting



and completing each major element of the work to be done in  developing the



revision.  Major milestones may include (a) the development  of the control



strategy, (b) preparing draft legislative amendments,  where  necessary,



(c) public hearing dates, and (d) submission of plan  to EPA.  The State



should also advise the Regional Offices of the agencies responsible for the



development of the plan revision and where appropriate, an identification



of the responsibilities of each agency when multi-agencies are involved with



the development of the plan revisions.  The notice should clearly state



that EPA will begin to take action to disapprove the  pertinent sections of



the SIP and/or to develop, propose and promulgate EPA  regulations, if the



State does not provide an indication of its intent to  comply with the revi-



sion notice within the stated time period.




i.  The  Federal Register Notice  should declare that all existing elements



in  the plan  remain  in effect  (and  are fully enforceable) until the revision



is  submitted by the State  and approved by EPA or EPA promulgates any needed



revision.   In  other words, there should always be a plan in  effect.  Also,



since  only  the specific  regulations that  are added or changed by a plan




revision are subject to a  Section  307 challenge, it would be prudent




                               31

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in those cases where possible,  not to change any  currently  approved



regulations but rather add new  regulations  to the SIP.   However, where



the alternative of revising an  existing  regulation is  clearly  superior



to adding a new regulation, fear of litigation should  not  deter  a



revision of the existing regulation.



j.  The Notice should point out that the plan revision  must be submitted



in accordance with the provisions of 40  CFR 51.4, Public Hearings,  and



51.6, Revisions and the other requirements  of Part 51.   In  addition,  the



Federal Register Notice should  contain a justification  indicating why



the finding of a plan deficiency is not  subject to public  comnent at  this



time.  OGC believes that the Agency's technical determination  of the



necessity for a plan revision does not need to undergo  rulemaking procedures



at the time of calling for a plan revision.  The public will have ample



opportunity to comment on the action when the plan revision has  been  sub-



mitted by the State (or when EPA proposes its own remedial  measures).  As



with other plan submittals, the public must be advised of  any plan  revision



submission and be allowed to comment on  the action.  An example  Federal



Register notice is provided in Appendix A.



2.  Other Federal Register Actions



     In  addition  to the Federal Register Notice discussed  above, other



Federal  Register  actions need to be taken.   These actions  depend upon the



State's  response  in relation to the plan revision requirement.



     In  those  cases where the State submits a  letter of intent,  followed



by a plan revision, no  action should be taken  to  disapprove the original



SIP  prior to  the  review of the SIP revision.   After the State submits



its  revisions  and EPA  reviews them, concurrent actions can  be taken to
                              32

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disapprove particular parts of the original SIP and approve the new or
revised parts.  Such procedure would minimize the paper work involved
in the preparation of the Federal Register and briefing memo documents,
and avoid discontinuities in the regulatory process.
     In those cases where a negative response or where no letter of
intent is received from the State in relation to the request to modify
the SIP, or where no plan revision is submitted as required, the Agency
shall  take action in a timely fashion to simultaneously propose disapproval
of the pertinent portions of the SIP and propose EPA substitute and/or
additional regulations.   Such disapproval  and regulatory actions should
seek to minimize disruptions in implementing acceptable regulations, and
be taken in such a manner so_ that a_ plar^ remains in_ effect at_ aj 1 time.
Agency procedures for preparation of  Federal  Register actions
are provided in OAQPS Guidelines Series  Document No. 1.2-005A
(revised).
3.  Letter to the Governor
     It is recommended that a letter be  sent to the Governor(s) of the
affected State(s) of the necessary action  prior to publication  in the
Fe de ra 1 Register.  Since some explanation  of the reason for the plan
revision is in order, it may be appropriate to attach a draft copy of
the Federal Register notice.
     The State Agency should also be advised of the pending Federal  Register
action.  However, since  the State should already be intimately  aware of
the content of the call  for plan revision  from ongoing discussions with
them on the attainment problems, the letter to advise them of the
publication of the notice in the Federal  Register is more of a  courtesy.
                                     33

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C.   PLAN SUBMITTAl
     Once the plan revision is submitted by the State, the Agency pro-
cedures outlined in the OAQPS Guideline No. 1.2-005A govern the review
and approval/disapproval process.
                                  34

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V.  Overview of Necessary Actions in Relation to Substantially
Inadequate SIP's
     The purpose of this Chapter is to provide an overview of the
necessary actions in relation to identifying substantially inadequate
SIP's and calling for Plan Revisions.   While this guideline thus  far
has discussed procedures to be followed for all  areas of the nation
to determine if a SIP is substantially inadequate, certain follow-up
actions are different, depending upon whether an area has been designated
as an AQMA (Air Quality Maintenance Area) or as  non-AQMA.  Consequently,
two slightly different flow charts that sequentially identify the necessary
actions are provided for AQMA's (Table 2) and non-AQMA's (Table 3).  These
minor differences can be seen in Steps 1  and 4 and result from specific
activities and requirements for AQMA areas that  do not exist for  non-AQMA
areas.
                                35

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                               TABLE 2
ACTION STEPS FOR AQMA AREAS WKLRE SIP'S ARE SUBSTANTIALLY IMADEQUATE. TO
                             ATTAIN NMQS


STEP 1.  RO's, with State and local agency assistance as appropriate, determine
         those areas of the nation for each criteria pollutant where the SIP is
         substantially inadequate to attain NAAQS.   Determination by 7/76.
         (RO's may wish to use as input the AQMA analysis proposed (in the  main-
         tenance regulations) to be submitted by the State to EPA by April, 1976.)

STEP 2.  RO discusses findings of analysis with State and local agencies and
         determines which control regulations should be modified or added by 7/76.

STEP 3.  RO advises Governor of State by letter of necessary plan revision  by 7/76.

STEP 4.  RO publishes a FederaJ Register Notice (without proposal) to publicly
         announce need for plan revision, by 7/76.   Proposal indicates among
          other things  that  all  emission  limitations  (as  needed) which  it is
          reasonable to  anticipate  will be  achievable within  a  reasonable
          period of time  must be submitted  by 7/77,  other measures  (e.g., land
          use  and transportation measures)  by 7/78 and a  requirement  that the
          State notify EPA within 60 days of its intent  to propose  and  submit
          plan  revision.  Further,  RO should advise  State that  plan revision should
          be developed in relation  to Subpart D and  other EPA guidance  for mainten-
          ance  area.  Also,  since the final 40 CFR 51 regulations  for maintenance
          plans may specify  a  constraint  (such as July,  1978) for  subn;ittal of
          maintenance plans  in non-attainment AQ'IA's, this should  be  noted  in the
          Federal

STEP  5.   State submits  to RO  within 60 days letter  of intent with  schedule for
          completion of major  plan  items  to develop  plan  revision.  If  no response,
          RO proposes plan revision to  attain and maintain fiAAQS in a timely
          fashion.

STEP  6.   State submits,  by  7/77, plan  revision with  adopted  regulations-


STEP  7.   RO notifies public  of  7/77 plan submittal  in the Federal  Register, seeks
          coninents  and proposes  to  approve  or disapprove  7/77 plan  submittal.

STEP  8.   RO approves 7/77 plan  submittal,  or disapproves and proposes  EPA  substi-
          tute  regulations.

STEP  9.   Where necessary, State  submits  by 7/78 othsr control  measures  needed
          to attain and maintain  national standards,  such as  land  use and trans-
          portation control  measures.

STEP  10.  RO notifies public  of  7/78 plan submittal  in the Federal  Register, seeks
          comments  and  proposes  to  approve  or disapprove 7//8 plan submittal.

STEP  11.  RO approves 7/78 plan  submittal or disapproves  ana  proposes EPA substi-
          tute  measures.
 NOTE:   (1)   Dates  do  not  apply to those AQMA's where only a maintenance plan
          is  required.   In such cases,  the Regional Administrator can establish
          any date for submittal of  a plan that considers maintenance only
          (i.e.,  not attainment and  maintenance).

        (2)   All  dates  are latest dates acceptable  for  this sequence of events.

        (3)   Step 1, 2,  3  and  4 all  have end dates  of July 1976.  It should be
          noted  that such  steps are  sequential and  require time between steps for
          implementation.   It  is recommended that these steps be spread out from
          April  to  July, 1976, however  Regional Offices have the latitude to
          establish interim dates as they consider  appropriate.  Only the July,
          1976,  notice to  the  States of a need for  a plan revision  is a firm
          Agency date.
                                       36

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                              TABLE  3
 ACTION STEPS FOR NON-AQMA AREAS  WHERE  SIP'S  ARE  SUBSTANTIALLY
                  INADEQUATE^ TO ATTAIN  NAAQS


 STEP 1.   RO's,  with State and  local  agency assistance  as  appropriate,
          determine those areas of the  nation for each  criteria  pollutant
          where  the SIP  is substantially inadequate  to  attain NAAQS.
          Determination  by 7/76.

 STEP 2.   RO discusses  findings of analysis with  State  and local  agencies
          and determines which  control  regulations should  be modified
          or added by 7/76.

 STEP 3,   RO advises Governor of  State  by letter  of  necessary plan  "
          revision by 7/76.

 STEP 4.   RO publishes  a Federal  Register Notice  (without  proposal) to
          puolicly announce  need  for  plan revision,  by  7/76.  Proposal
          indicates  among  other things  that all emission limitations (as
          needed)  which  it is reasonable  to anticipate will be achievable  '
          within  a reasonable period  of time must  be submitted by 7/77,
          other measures  (e.g., land  use  and  transportation measures)
          by 7/78 and a  requirement that  the  State notify EPA within 60
          days of its intent  to propose  and submit plan revision.

 STEP 5.   State  submits  to RO within  60 days  letter  of  intent to
          develop plan  revision with  schedule for completion of
          major  plan items to develop plan revision.  If no
          response, RO  proposes plan  revision to  attain and main-
          tain NAAQS'in  a timely  fashion.

 STEP 6.   State  submits, by 7/77, plan  revision with adopted  regulations
          up to  RACT (as needed).

 STEP 7.   RO notifies public of 7/77  plan submittal  in  the Eedej-al  Register,
          seeks  comments and proposes to approve  or  disapprove 7/77 plan
          submittal.

 STEP 8.   RO approves 7/77 plan submittal, or disapproves  and proposes
          EPA substitute regulations.

 STEP 9.   Where  necessary, State  submits by  7/78 other control  measures
          needed to attain and  maintain national  standards.

 STEP 10.  RO notifies public of 7/78  plan submittal  in  the Federal  Register.
          seeks  comments and proposes to approve  or  disapprove 7/78 plan
          submittal.

 STEP 11.  RO approves 7/78 plan submittal  or  disapproves and oroposes EPA
          substitute measures.
 NOTE:

(1)  All dates are latest dates acceptable for this sequence of events.

(2)  Step 1, 2, 3 and 4 all  have end dates of ,lnl« 1976.  H should be
noted that such steps are sequential and require time between steps for
implementation.  It is recommended that these steps be spread out from
April to July, 1976, however Regional Offices have the latitude to
establish interim dates as they consider appropriate.  Only the July,
1976, notice to the States of a need for a plan revision is a firm  v
Agency  date.
                                  37

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                             APPENDIX A



                  (Example Federal  Register Notice)



                            NON-AQMA AREA



                   ENVIRONMENTAL PROTECTION AGENCY



               APPROVAL OF STATE IMPLEMENTATION PLANS





Notice of Required Revision to Part of the State Implementation Plan for



the Metropolitan Smogtown Intrastate Air Quality Control  Region



      On May 31, 1972 (37 F.R. 10842), pursuant to Section 110 of the Clean



Air Act, and 40 CFR Part 51, the Administrator approved the control  stra-



tegy for the attainment of national primary and secondary standards  for



suspended  particulate matter in the Metropolitan Smogtown Intrastate



Region.  The plan was designed to attain these national standards by date,



 (such  as June  1975).



      On the basis of recent air qual-ity data submitted by the State in



fulfillment of the requirements of Section 51.7  (Reports), and from the



evaluation of various compliance actions taken by the State to implement



the adopted particulate emission control regulations of the applicable



plan, it is the technical judgement of the Regional  Administrator for



Region III, that the presently approved  control strategy portion of  the



plan for particulate matter (i.e., pursuant to 40CFR Section 51.13)  is



inadequate to attain the national particulate matter standards.  There-



fore it is necessary to add additional control measures- to the plan  or



revise one or more existing regulations  for control  of particulate matter.



Specifically, this finding is based upon a detailed diffusion modeling



analysis of the urban-industrialized section of Southeast Smogtown,  (State)



This analysis, which has been summarized in a technical report entitled

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"The Suspended Participate Problem in Smogtown"  is available for inspec-



tion and copying at the Environmental Protection Agency,  Region  III,



Curtis Building, 6th and Walnut Streets, Philadelphia,  PA  19106,  and the



Public Information Reference Unit, Room 2922 (EPA Library),  401  M  St.,  S.W.,



Washington, D.C.  20460.  Copies of this technical report have been  pro-



vided to the appropriate State and local air pollution  control agencies



within the (State).



      The mathematical diffusion modelling analysis, summarized  in the



report, indicates that two sources contribute significant particulate



matter emissions to the atmosphere in southeast Smogtown.  Emissions from



these sources, which include an uncontrolled cement plant and a  moderately



controlled integrated steel mill, are such that national  particulate



matter standards are predicted to be violated beyond the  scheduled date



of attainment of the national standards (i.e., July 1975).  The



report also identifies that the intermittent open burning at various dumps



and small uncontrolled incinerators  contribute to more  localized excursions



above the national standards.  Based upon this analysis,  the Regional Ad-



ministrator, Region III, has determined that a substantial  (in the range of



30%) reduction of 1974 annual particulate matter emissions from these



plants or other sources will be needed  to provide for the attainment of the



standards.  Further, more  vigorous enforcement of currently adopted



regulations for controlling open  burning and incinerators must be under-



taken by the appropriate air pollution  control agency.   Alternatively,



other equivalent improvements in  the particulate  control  strategy may be



employed, as determined by the State and approved by EPA.



      Because of this  identified  deficiency, the  Regional Administrator



finds that a revision  to parts of the  control strategy for  particulate





                                  A-2

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matter in the applicable plan is needed.   This Federal  Register; Notice
is intended to officially advise the (State)  of this  requirement.
Accordingly, the State shall  prepare and  submit, by July 1,  1977,  a
plan revision containing adopted emission limiting regulations, as
needed, which it is reasonable to anticipate  will  be  achievable within
a reasonable period of time to provide for the attainment and mainten-
ance of the national primary particulate  matter standards.   If additional
control measures (e.g., land use and transportation measures) are
needed, such measures may be submitted no later than July, 1978.  The
plan revision should identify the nature and sources of emissions
within the Southeast portion of Smogtown and demonstrate how the adopted
regulations will provide for the attainment and maintenance of the
national standards^.  The plan should include a demonstration that
emission increases  that will result from projected growth of population,
industrial activity, etc., will not cause the national standard to be
violated.  Compliance schedules for any source affected by any new or
revised regulation  must be submitted in accordance with the  requirements         ;
of 40  CFR  51.15  (Compliance Schedules).  The plan revision should also           i
indicate any  additional resources needed to implement the control  plan
beyond tliose  already provided for in the plan, along with the State's            !
                                                                                 i
commitment  to provide additional manpower and money to implement the con-        i
trol measures.   If  responsibility for implementing any portion of the
plan revision is delegated to other State and/or  local agencies, a               l
description of  the  specific responsibility of each agency in implementing        <
                                                                                 i
                                                                                 i
the plan shall  be submitted.  The plan revision shall be submitted by            ;
the State  in  accordance with the provisions of Section 51.4, Public
                                                                                 i
Hearings,  and Section 51.5, Submission of Plans and otherwise  fulfill            •
                                                                                 l
the requirements of Part 51.
                               A-3

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     The State is advised that the plan revision must provide for the
attainment of primary standards as expeditiously as practicable.  It is
the judgment of the Regional Administrator that adequate time exists
for the State to revise the plan so as to provide for attainment of
primary standards  by mid-1977  as  provided under  the Clean Air Act.
If the plan revision requires  substantially more restrictive emission
controls  than are  presently included  in  the approved plan, and  if
the requirements of 40  CFR  51.30  are  met, then  an extension  to  mid-
1977 can  be approved by  the Agency for the attainment of national primary
particulate matter standards.   Such an extension should be formally
requested by  the Governor when  submitting the plan revision.  The State
is further advised that  additional time  can be  provided for  the attain-
ment of secondary  standards, so long  as  such standards are attained within
a  "reasonable time".  The revised plan  shall  indicate the date the
national  standards will  be  attained.
     The  Governor  shall submit,  within  60 days, a letter of intent to
the Regional  Administrator, EPA,  Region  III which  identifies the various
action  steps  (along with target dates for completion) which  the State
will take to  develop the plan  revision in accordance with the require-
ments  set forth  in this  notice.   The  S, ite must  also identify the agencies
that have been given responsibility to prepare  the plan revision.  Failure
by the  State  to  submit  a letter of intent within the allotted 60 days
will be considered by EPA  as  an indication that  no plan revision will be
forthcoming  from the State.   In this  case, EPA will begin to develop for
promulgation  a federal  plan to attain and maintain national  standards.
                                 A-4

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      All of the applicable plan remains in effect until the plan revision
is submitted by the State to EPA and is approved by EPA or until  EPA
promulgates substitute (or additional) regulations.
      This notice is not subject to rulemaking procedures.  The need for a plan
revision is based upon a technical  finding of the Regional Administrator
which clearly shows that the control strategy for particulate matter in
the Metropolitan Smogtown Intrastate Region is inadequate and needs to be
revised.  Authority for such action is provided in Sections 110(a)(2)(H)
and 110(c) of the Clean Air Act, 1970.  Ample opportunity for public comment
on the Regional Administrator's determination will be provided.  If the
State develops its own revisions and submits them to EPA, public hearings
will be required at the State level and EPA will provide opportunity for
written comments prior to taking action on the submission; if EPA must
propose and promulgate its own regulations, EPA will  provide opportunity
for written comments and, if the State held no hearing on the revisions,
will provide opportunity for a public hearing.   Authority:   Section
110(a)(2)(H) of the Clean Air Act,  as amended, 42 U.S.C. 1857c-5(a)(2)(H)
and Section 110(c) of the Clean Air Act, as amended,  42 U.S.C.  1857c-5(c).
Date
                                     Regional  Administrator
                                     Environmental  Protection Agency
                                   A-5

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           APPENDIX B.  GUIDELINES ON AMBIENT TREND MONITORING


1.   General Guidelines for Regional  Office Monitoring Programs       1.2-007
     PURPOSE:  General summary of existing ambient trend moni-
               toring guidelines
2.   Guidelines for Interpretation of Air Quality Standards           1.2-008*
     PURPOSE:  Answer questions on how NAAQS and air quality  is
               related
3.   Guidelines for Network Design and Instrument Siting             1.2-012*
     PURPOSE:  Network design and instrument siting criteria
4.   Procedures for Flow and Auditing of Air Quality Data            1.2-013*
     PURPOSE:  Steps to insure valid  data
5.   Guidelines for Evaluation of Air Quality Trends                 1.2-014*
     PURPOSE:  Trend evaluation
6.   Guidelines for the Evaluation of Air Quality Data               1.2-015*
     PURPOSE:  Evaluation methodology
7.   A Description of Analytical  Techniques and  Associated SAROAD     1.2-017
     Method Codes Used in Storing Data in NADB
     PURPOSE:  Decoding of method codes  used in  NADB
8.   Designation of Criteria Pollution Analytical  Methods as          1.2-018*
     Acceptable/Not Acceptable for Purposes of Data Analysis
     PURPOSE:  Acceptability of data  and instruments
9.   Air Quality Monitoring Site Description Guidelines               1.2-019*
     PURPOSE:  Information on Monitoring Sites
*Also included in Volumn  11,  Air Quality  Maintenance Guidelines

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                             APPENDIX C
ENVIRONMENTAL
PROTECTION        TRANSMITTAL
AGENCY
Addressee
     1270.5
                                                       October 15,  1973
             DELEGATIONS OF AUTHORITY - AIR AND WATER PROGRAMS
MATERIAL TRANSMITTED:

    EPA Order No. 1270.5 - Delegation of Authority to Request States to
    Revise  State Implementation Plans.
MATERIAL SUPERSEDED:

    None.
                                      \

FILING INSTRUCTIONS:

    FtJe the attached material in numerical order in a three-ring binder
    established for the EPA Directives System.
                                 Howard M. Messner
                           Deputy Assistant Administrator
                                 for Administration
Dist: Directives Distribution

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                                   C-2
ENVIRONMENTAL
PROTECTION                ORDER
AGENCY
1270.5
                                                             October 15, 1973
                 DELEGATIONS  OF AUTHORITY - AIR AND WATER  PROGRAMS
                   DELEGATION  OF AUTHORITY TO REQUEST STATES TO
                         REVISE STATE IMPLEMENTATION PLANS
 1.   PURPOSE.  This Order delegates  to the Regional Administrators the
 authority  to request States to revise State Implementation Plans under
 Section  110(a)(2)(H)(ii) of the Clean Air Act.

 2.   BACKGROUND.  Section 110(a) (2) (II) (ii) of the Clean Air Act  provides  ••
 for  the  revision of State Implementation Plans (SIF's) "whenever the
 Administrator finds on the basis of information available to  him that the
 plan is  substantially inadequate to achieve the national ambient air
 quality  primary or secondary standard which it implements."  In view of
 the  emphasis on utilizing regional  offices in supervising the SIP's, a
 delegation of authority to the Regional Administrators to request the
 revisions  is in order.

 3.   DELEGATION.  The Regional Administrators are delegated authority to
 perform  the responsibilities indicated above within their respective
 regions.

 A.   LIMITATIONS.

     a.   Revisions will be requested only when such revisions  are clearly
 necessary.

     b.   Where the requested revision would affect emission control
 regulations significantly, or the enforcement thereof, Regional Admin-
 istrators  should obtain the concurrence of the Assistant: Administrator
 for  Air  and Water Programs and the  Assistant Administrator for  Enforce-
 ment and General Counsel.

     c.   Where the requested revision would have significant national
 policy  implications or would establish a significant precedent, the
 concurrence of  the aforesaid Assistant Administrators is required.
Dist:  Directives Distribution                                        Initiated by: AF

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                              C-3
                                          ORDER
                                                              1270.5
                                                          October 15, 1973
     d.   Insofar as other revisions are concerned, Regionai Administrators
 should  simply notify  the two Assistant Administrators of requests made.
     e.   This authority may not be redele
                                      RdpseB.1 E. Train
                                       Administrator

                                                                 &
PAS 4

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