Guideline Series (OAQPS No. 1.2-016) Guidelines for Designation of Air Quality Maintenance Areas


      GUIDELINE SERIES
                  OAQPS  NO.  1.2-016
           GUIDELINES FOR DESIGNATION OF
           AIR QUALITY MAINTENANCE AREAS
US. ENVIRONMENTAL PROTECTION AGENCY
   Office  of Air Quality Planning and Standards

      Research Triangle Park, North  Carolina

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                                                    450R74O06
                                                      it
                                                      OAQPS Guideline
                   GUIDELINES FOR  DESIGNATION  OF

                   AIR QUALITY MAINTENANCE AREAS
                  Standards Implementation Branch

                Control Programs  Development Division

             Office of Air Quality Planning and Standards

                U. S. Environmental Protection Agency


                       January 11, 1974
NOTE:   Revisions and additions at end

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                    Preface

     These guidelines are presented herein in their final  form.
Although a "Second Draft" dated December 21, 1973, had been
circulated,  it contained only the  first  three  sections.  The
first three  sections  with minor revisions  are  enclosed herein with
the  remainder of the guidelines for completeness.   The revisions
of the first three sections are:
     (a)  The Table of Contents was revised to include three
          Appendices
     (b)  In the flow diagram on p. II-l, the reapplication of
          the initial designation criteria has been eliminated.
     (c)  On p. 11-3, in the list of types of areas which  might
          be used for designation, Vcountles" is takenout  of the
          heading "groupings of," since a single county could,
          in some cases be designated as an AQMA.
     (d)  On p. III-l, reference to the reapplication of the
          initial designation criteria has been deleted.
     (e)  On p. III-l and III-2, criteria related  to air quality
          have been revised so that the  air quality data for the
          past two years must be considered in applying the criteria.
     To aid the reader in following the techniques for projecting
emissions and air quality, three example calculations are  presented
in Appendix B for a hypothetical area to determine whether the area
has  the potential for violating a NAAQS within 10 year.
     To aid the States in estimating future manpower requirements
for  the maintenance  of standards program, Appendix C contains a list
of tasks anticipated within the coming year and a half.

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                TABLE  OF  CONTENTS
  I.   Background and Introduction
 II.   General  Instructions  and  Discussion
IH.   Initial  Designation Criteria
 IV.   Method of Projecting  Emissions
  V.   Instructions  for Modeling Air Quality Concentrations
 VI.   Projections of Demographic and Economic Indicators by SMSA
  Appendix  A - Basis for  Initial Designation Criteria
  Appendix  B - Example of Analyses for a Hypothetical SMSA Employing
               the  "Back-Up" Method of Estimating Emissions
  Appendix  C - List of Tasks to be Performed for Maintenance of
               Standards  Program

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                          AIR QUALITY MAINTENANCE AREAS

    Background and introduction
    Pursuant to 40 CFR 51.12(e), published on June 18, 1973,  in the Federal
    Re£is_te_r, Voljme 38, P.  15834, all  State Implementation plans  "...
    shall identify those areas (counties, urbanized areas,  standard
    metropolitan statistical areas, et cetera) which, due to  current air
    quality and/or project growth rate, may have the potential  for
    exceeding any national standard within the subsequent 10-year  period."
    After  areas  are identified by the States, EPA will review these
    designations and will r.repare an official list of  areas  by June 1974.
    For these areas, the States must then perform a thorough  air quality
    analysis of each of these  areas ;  where this analysis shows that an
     orefiwill definitely not maintain a NAAQS during the 10-year period,
    a plan must be developed for that  area  which demonstrates that the
    standard will be maintained.
    As -^.ate-4 in the preamble to the above-cited rulemaking, EPA intends to
    provide assistance to the States in
         a.  identifying the areas (for reference, "air quality maintenance
             areas" - AQMA's) which may exceed a national  standard within
             the next ten years, and
         b.  analyzing the impact of growth and development oh air quality in
             such problem areas.

     These present guidelines are to assist the States in identifying AQMA's
and do not require as extensive an analysis as will the guidelines for
analyzing the impact of growth which will be issued in the Spring of 1974;
guidelines for preparation of plans for maintenance of air quality will be
issued in late summer of 1974.  The overall timetable for plan development
with regard to 40 CFR 51.12, paragraphs (e) through (h) is:
     March  18, -1974      State submission of identification  of AQMA's
     June 18,  1974        EPA publication of list of AQMA's
     June 18,  1975        State submission of:
                         a.   Impact  on  air  quality  of  projected  growth  in
                             AQMA's
                         b.   where  needed,  a plan  to prevent any  national
                             ambient air quality standards  (NAAQS)  from

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                            being exceeded over the 10 year period from
                            the date of plan submittal.
b .IP(Mi led  timetable of State and EPA activity over the next two years
.i,r t:\(- maintenance of standards program is presented in Table  1-1.
    EPA intends that the guidelines be  easy to follow
yet still be sufficiently responsive to insure that as many appropriate
AC'MA's as possible are designated without over-desigation.  Because of the
•r.omp';r:x nature- of the tasks involved and because of the many uncertainties
•>.neivrit in v\e projection of emissions and air quality, the guidelines
are written to obtain some degree of consistency in the information to be
Sub.ni ;:t'_sci by the States, wnile still allowing for innovative approaches.
    ?.-.ur to preparation of these guidelines, EPA consulted with several
State and 'scxal air pollution control agencies and regional planning com-
missions.  EPA has attempted to incorporate the.advice thus obtained in
these c'j-idel ii;es.   Although every attempt has been made to anticipate and
address questions  which may arise, invariably unresolved issues will occur.
Where questions do arise it is recommended that the appropriate EPA Regional
Office be contacted for guidance.
    The guidelines for AQMA designation are written for the State agency
responsible for designation.  In most cases this will be the State air pollu-
tion control agency.  Because the impact of the provisions for maintenance
of standards will  affect areas which are of concern to other State agencies
and local general  purpose governments (such as those responsible for
regional land use and transportation planning, water pollution control, etc.),
it is advisable for the designating agency to solicit comment from these agencies
and involve tnem in the designation process.
                               1-2

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Federal EPA Designation of AQMA's
    As indicated above, EPA will review the list of designated AQMA's
submitted by the States and will publish, after allowing for public
comment, an official list of AQMA's by June 1974.  Due to time and manpower
constraints, EPA will not be able to analyze in detail  each State which
does not submit any material concerning AQMA  designations.  Consequently,
EPA's designation for State.; which do not offer a submission will be on
the basis of SMSA's whose growth rates for particular demographic-economic
indicators exceed a specified value.  In addition, the present value of
                                                          i
the indicator, current air quality and the meteorological conditions which
present a pollution potential would be incorporated in EPA's criteria  for
AQMA designation.  In most cases, actual emissions and air quality per se
would not be projected by EPA.  The critical growth rates would be determined
as follows:
    a.  Percentage growth rates for population and earnings by industrial
        category have been obtained on an SMSA basis for the years 1975-1985.
    b.  SMSA's have been listed by regional priority classification for
        each pollutant and ranked by percentage growth rate for population
        and earnings by industrial category.
    c.  Using best judgement, demographic-economic indicators would be
        selected as representative of each pollutant-source category combina-
        tion.
    d.  After scrutiny of the spread of growth rates, critical growth  rates
        would be selected using best judgement for each demographic-economic
        indicator corresponding to a pollutant-source category combination.
    The critical growth rates per demographic-economic indicator would vary
depending on the pollutant priority classification of the AQCR in which  the
                                1-3

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:>MSA is located.  Thus, a lower critical growth rate would be specified
for those areas having a currently significant air quality problem
(Priority I regions) than for those areas which do not have a currently
significant air qi^ility problem (Priority III regions).
fjture Guidelines
    In addition to these guidelines on AQMA designation, EPA will  publish
two other sets of guidelines, one concerning the detailed analysis and
projection of air quality for the AQMA's and the other concerning  the
develorient of a plan for maintenance of NMQS where needed.  These future
g>-ic;:l ines are briefly discussed below:

A.  Guidelines for AQMA Analysis
    The analysis step is intended to determine whether air quality limits
are inaeect threatened, and if so, when, where, and which are the principal
sources ••'nvolved.  The results of this analysis will be useful in  deter-
mining whether an SIP revision is necessary, and in formulating alternative
plans if they are needed.
    Descriptive analysis would proceed along the general lines described
below concerning analytical  procedures for selecting AQMA's except that
the analysis  would  be more thorough.  In particular, the following steps
would be followed:
    1.  The quantity of emission of each pollutant for which the AQMA is
        designated would be projected to 1985.  This projection would
        consider:
        a.  present emissions by source category and, if possible, by
            location.
        b.  expected growth of each source category based on past trends
            and highly probable future contingencies.

                                1-4

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        c.  Present and highly probable future emission restrictions
            on new and existing sources.
    2.  The 1985 projected emission inventory would be allocated to
        the land in the least desirable* pattern which would be  permitted
        under present land use restrictions.   This "scenario" is the  one
        which would result in the most centralized locations of  new sources
        of emission.  Presc.it zoning patterns and land use plans would
        be used in allocating new sources to the land.
    3.  1985 air quality would be estimated from the emission pattern scenario,
        preferably using a calibrated diffusion model.  If this  is impossible
        in the time available, a less sophisticated model  musSt be used.
    The models, emission factors, growth projection techniques,  etc.  suitable
for performing the analysis will be forthcoming in May of 1974.

B.  Guidelines for Development of Air Quality Maintenance Plans
    In late spring or early summer 1974, EPA  will issue guidelines to States
on the preparation and submittal of 10-year air quality maintenance plans.
These plans, which will be due on June 18, 1975, will pertain only to portions
of States designated as Air Quality Maintenance Areas (AQMA's') by the Adminis-
trator in June 1974.  The guidelines will be organized around four subject
areas.  The first relates to the mechanics of preparing and implementing  the
plans.  Topics ranging from plan format to procedures for categorizing emis-
sion sources will be covered.  The second subject a.rea deals with the
evaluation of the air quality implications of local land use and transportation
plans.  It may be discovered in some AQMA's that growth plans are incompatible
with air quality maintenance, and need to be revised.  The third subject  area
*Least desirable from an air quality maintenance point of view
                              1-5

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will include a list of maintenance strategies.   Emission  allocations,
transportation controls, fuel  and energy conservation  measures, and
other strategies will be discussed, along with  procedures  to quantita-
tively estimate their impact on air quality.  The  final subject area
will cover the coordination of air quality maintenance plans with other
environmental planning activities.  These include  water quality planning
and che review of environmental impact statements.
                                  1-6

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J A S 0 N 0

"Ti/3 1 1974 ! 1975



EPA Crafts Analysis State Conducts Analysis and Develops Internal
Guidelines (51/2 ' Control Plans (9 months) State Review
months) (2 months)

(1
mo)


States
Revise
Plans
(1 1/2
months)
EPA Reviews Plans and
Develops Substitute
Plans for States Failing
to Submit (4 months)



TABLE 1-1. MAINTENANCE OF AIR QUALITY STANDARDS
                     ACTIVITY SCHEDULE
11/29/73

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II.  General Instruction and Discussion

     The general approach which this guideline  presents 1s depleted as

follows; the Roman numerals refer to the portions of the Gu1del1n«1n which

that item is described:


                              all SMSA's
                                 1
     SMSA's automatically  '  Apply initial
     excluded as AQMA's
designation
 criteria
   (III)
. SMSA's automatically
  included as AQMA's
                                       SMSA's neither automatically
                                       excluded or Included
                             Predict 1985
                            emissions (IV)
                              Predict 1985
                             air quality (V)
SMSA' excluded
as AQMA's
                              Determine If
                               NAAQS's  are
                               maintained
                           SMSAIs  included
                           % f  AS1UAIf
  Tas AQMA's

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i';eo',|r\v;j 'i(,r> i area.-, i.o be considered
(!) Tivvc 3ppr-nr: to i>> a nr;ed to specify which areas, as a minimum,
'••.en Id ; <":>>.) iy,:t'd ir, determining 'w/iich areas are or are not to be
•..•.•v.r:;i ,..•,' as "vjMA1 r, The areas selected are the Standard Metropolitan
v:;.,-;v?.; -j.\ .-.--or- 'y'SA'r.) 35 de^r.cd by the Offic? of Management ?rd
t
v!:> e'. Y-C;>:MV ".V f-ji't-a'j ff t.-,e Budget). T;u; r-t; ./.-,.'.--• :'or cno".iuig
Si'iSA's are:
5i"x-''s nistorically exhibit higher growtn rates of population
t;io:i non-Si'1S-:'. ar'jas.
SMoA's exhibit the highest concentrations of population and
Projections of population and economic indicators are avail-
able on an SMSA basis.
A rear, of SMSA's change with time as population density increases
facilitating future changes in the designation of AQMA's.
SIISA's account for roughly 70 percent of the nation's population
l-ut only about 10 percent of the total 'land areas.
rt SMSA, alone or in its entirety, however, may not always be
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constitute the boundaries of the area. Designation by (currently
defined areas, however, does not mean that the subsequent detailed
analysis of the AQMA and possible control strategy must apply to the
entire AQMA as originally designated—the analysis and plan can be
restricted to selected problem areas within the AQMA. On the other
hand, one should be aware that designated', areas have been referenced
in the proposed regulations for review of indirect sources in all but
three States (38 F.R. L9893, Federal Register of October 30, 1973).
If the regulation is promulgated as proposed, the size of facilities
which would be exempt from review will be smaller in the designated
areas (AQMA's) than in the non-designated areas. Until EPA publishes
the list of AQMA's in June 1974, all SMSA's would, for purposes
of the proposed indirect source review regulation, be considered
designated areas.
In addition, one should be aware of possible relationships between
the designated areas (AQMA's) and the areas to be chosen under the
forthcoming regulations concerning significant deterioration. For
ii
instance, if the significant deterioration regulations provide that some
(probably urban) areas are permitted to deteriorate up to the secondary
national ambient air quality standard, these areas will probably be the
same areas as the AQMA's. Therefore, it might be appropriate to designate
an area large enough to allow for the proper amount of desired growth.
A non-exhaustive list of types of areas which might be used for
designation include:
AQCR's
SMSA' s
Urbanized Areas
Counties
f Cities
rouplngs of: ^ Townsn1ps
VJJoroughs
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Planning regions used for transportation, land use or other planning
Sub-state? planning districts
(?) Designations should be pollutant-specific and should indicate
tr;«? poll'Jt;ints for which the area is designated. The detailed analysis
required Tor each of the finally designated AQMA's would then be done
only on the basis of tnose pollutants which are identified as problems
in exceeding air quality standards in the future. • f
(j) r:- ijnifonnit/ and to avoid proliferation of designated AQMA's a
sin-Vie Boundary for each AQMA should be chosen regardless of the number
ov oci"ut-•/•; thin the area may overlap or be mutually exclusive (e.g.,
ono port of an AQMA may experience growth in mobile source pollutants
whiip another part, may suffer an increase in SOp emissions from fuel
irotritiostion), but only one AQMA should be designated which enclosed
all the problem areas of a particular geographic location.
(4) in the case of SI^SA's which cross State boundaries, the respective
States :.hould coordinate their-designations. An SMSA constitutes, by
definition, "...for general economic and social purposes, a single
community...". Therefore, it is recommended that, for an interstate
SHSA, one AQMA be designated jointly by the respective States. It is highly
desirable that, one single Integrated plan be adopted by all States Involved.
However, if this is not practical then all State plans in Interstate AQMA's
should HP at l9fl«t comoatible with one another.
It may be, however, that one State's portion of an SMSA may
experience growth in emissions while the adjacent State's portion may
not; in this case, it may be desirable for the growth State to designate
an AQMA in (and/or around) its portion of the SMSA, but for the non-
growth State not to designate in its portion. Obviously, one State
cannot designate an AQMA, a part of which is located in another State.
Interstate cooperation wi'il be necessary to resolve any conflicts.
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(5) Enclosed as an attachment to Part VI of these Guidelines are
projections of demographic and economic activity for SMSA's prepared
by the U. S. Department of Commerce, Bureau of Economic Activity
(BEA). BEA projections were made on the basis of SMSA's as they
existed as of January 7, 1972. > The Part VI attachment includes the
county composition of the SMSA's as they existed at that ttme.
Since January 7, 1972, several revisions to the composition of
SMSA's have been made, the latest in August 1972. Therefore, the
January 7, 1972, SMSA's may have slightly different boundaries than
the currently-defined SMSA's. The question arises as to which
I!
boundary should be used for AQMA designation. EPA recommends that
the January 7, 1972, SMSA's be analyzed. Those SMSA's which
are determined to be problem areas should than be designated as
AQMA's on the basis of the current (1973) SMSA composition. For
those SMSA's newly designated since 1972 and SMSA's in Puerto Rico
for which no BEA projections exist, the states should develop:their
own basis for projection based on data from various planning agencies
II-5
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(b) Factors to consider in designating AQMA's.
In deciding upon the particular boundaries of an AQMA, the
following factors should be considered.
1. The AQMA should include all of the territory which shares a
common air envelopeand a common aggregation of sources. This
will usually be an urbanized area plus some adjoining areas
which are now undeveloped but which are expected to develop in
the next 10 years or so. It may include satelite communities
which are now separated from the central urbanized area but
will, in 10-20 years, become part of the central urbanized
area and thus share the air resource.
2. Use of areas previously designated by agencies of various kinds
may have merit in that a data base may be available and a prolif-
eration of "regions" can be avoided. Examples are regional ;
planning areas; State designated planning areas; transportation
planning areas; etc.
3. Emission control and other air conservation measures necessary to
maintain air quality standards in the urbanized and developing
parts of major urban centers may be quite stringent. Applica-
tion of such stringent measures in isolated or undeveloped
areas may not be advantageous. Thus, inclusion of large rural
areas in an AQMA may not be desirable.
4. Design and implementation of air conservation measures will
involve certain governmental agencies. Common boundary lines
for AQMA's and one or some combination of jurisdictional areas
of implementing agencies may have merit from an operational point
of view.
II-6
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5. Long-range transport of pollutants is a matter of cbncern.
It is also true that if ambient air standards are maintained
near an aggregation of sources, such standards will also usually
be maintained at more distant locations. Therefore, it may not
be necessary to include those areas on the periphery of an
aggregation of sources in order to assure maintenance of standards
at locations distant from the aggregation of sources.
6. The influence of topography and geography on dispersion of
pollutants and on overall community growth patterns should be
considered.
7. When designating AQMA's, preparation of detailed air quality
projections and development of any needed abatement strategies
will need to be based on presently available land use, t;ransporta-
tion and other plans because of ti.ne constraints. It may be,
however, that new general regional development plans will be pre-
pared in the future because of air quality considerations or
other reasons. The AQMA designation would desirably be compat-
able with any such future community planning activity.
(c) Changes in Boundaries of AQMA's
The designation of the boundaries of an AQMA in March of 1974 will
not preclude changes in such boundaries at the time that more detailed air
quality analyses and abatement/maintenance plans are submitted in 1975, or
at some other time.
(d) Withdrawal of AQMA Designation
Areas designated in March or June or 1974 may be "de-designated" if
subsequent, more detailed analyses indicate that'in fact the ambient air
II-7
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''uilily standards will not be jeopardized In the coming 10 years.
Therefore, in borderline cases arising in initial abbreviated analysis,
it is appropriate to designate the area and proceed with more detailed
a; id ly so.'.
(e) Metropolitan Areas and Sparsely Urbanized Areas
The principal objective of designation of AQMA's and subsequent
development of plans to maintain ambient air quality standards is to
tm'vide a mechanism for management of general overall urban growth as
related to air -.juality, with due consideration of other aspects of
community growth. New source review procedures which involve a deter-
mination that the new source will meet emission regulations and not
cause or contribute to contravention of ambient air quality standards
will be .« part of the overall maintenance plan in urban areas. In
lightly urbanized areas and in rural areas, it is considered that
properly administered new source review procedures will be adequate
to assure maintenance of air quality standards and therefore, more com-
plex and burdensome maintenance programs will not ordinarily be needed.
11-8
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(f) Assumptions concerning fuel availability
In projecting emissions from fuel burning sources, certain assumptions
must be made concerning the future availability and use of types of fuel.
The assumptions used must be specified in the material submitted in support
of the designation. These will be considered valid if based upon current
trends and/or projected fuel use requirements. New facilities which might
change local fuel use patterns, such as refineries, nuclear power plants,
oil pipelines, coal gasification facilities, etc., but which have not already
been committed for completion by 1985, cannot be assumed to have an impact
on fuel availability in the designator, process. In addition, the current
fuel shortage cannot be assumed to continue ad infinitum. thus, resulting
in zero growth in emissions from fuel combustion.

(g) Assumptions concerning emission and air quality baselines
(1) Emission baseline--In order to estimate emissions between the
time standards are attained and 1985, it is necessary to determine
emissions at the time standards are attained. Some Sitate implemen-
tation plans (SIPs) contain these projections of emissions and these
can be used where available. If not available, these attainment date
emissions can be calculated by the method presented below, which is
based on concepts developed in the Manual for Analysis of State Imple-
mentation Plan Progress, prepared for EPA by the Research Triangle
Institute. Regulations which are currently in existence should be used
to project emissions. Regulations which are planned, but not yet pro-
mulgated, will not be accepted for such projections in the designation
process.
11-9
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(?.} Air quality base! ine--Several of the models presented below for
use in predicting air quality require the use of air quality at the
ti-Mf: uf implementation of existing regulations. As with emissions,
tno jiP's may contain projections of air quality at the time of full
SIP implementation, and these air quality values can he used. For
cases where air quality projections are not contained in the SIP, it
•r^y be ass-j-ned that the NAAQS will be achieved, unless there is reason
':• -je'iiev- otherwise. Alternatively, recent (1972-1973) ai r quality
dat.: r.iay otv projected to 1975 ar:d hence to 1985, making proper adjust-
•,ierti. tor urowth and scheduled abatement " i ,ns .
of the nature of photochemical oxidants, there may be
-3 which experience high oxidant concentrations caused by
rss emitted from either distant man-made sources or natural
sourcj-j. Is: is reconrnendeu that these rural areas not be designated as
AQiiA's in that it would be meaningless to design a control strategy for
these an:ar> since ihey do not contain controllable sources of hydro-
f.ii^-»ons. in addition, Federal programs are planned which will eventually
recku.e hydrocarbon emissions nationwide.
A similar problem exists for areas subject to high total suspended
parti cu! die matter concentrations due to uncontrollable fugitive dust
from rvitur-a ' causes. It. is recommended that parti cul ate matter measure-
ments resulting from such fugitive dust not be the basis for projecting
ai>- quality for the purpose of AQMA designation.
(h) A^'r quality standards to be considered.
The following national ambient air quality standards should be
considered in designating areas in which standards may be exceeded:
II- 10
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Pollutant _ Primary _ Secondary _ ^

Participate matter (a) 75 ug/m3. annual 150 yg'/m3* second highest
geometric mean 24-hr' average per year
(b) 260 yg/m3, second high-
est 24-hr average per
Sulfur dioxide (a) 80 ug/m3, annual arith- 1300 iig/m3, second highest
• metic mean 3-hour average per year
(b) 365 pg/m3, second high-
est 24-hr average per
_ year _ . _

Carbon monoxide 10 mg/m3, second highest 0-hour average per year

Photochemical 16Q yg/m3> second highest 1-hour average per year
oxioants
Nitrogen dioxide 100 pg/m3, annual cirithmetic average

For carbon monoxide, assume that the 1-hour standard will be maintained if
i
the 8-hour standard is maintained. As in the original SIPs, a demonstration or

achieving the oxidant standard will imply that the hydrocarbon standard is also

achieved.

Although States may designate on the basis of air quality standards

more stringent than the national ambient air quality standards, EPA itself

will, should the occasion ever arise, only act to the extent necessary to

insure attainment of the national ambient air quality standards.