United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711   August 1 984
Air
Ambient Monitoring
of Significant
Deterioration  (PSD)

-------
Ambient Monitoring Guidelines
  for  Prevention of Significant
        Deterioration (PSD)
                     by
           Monitoring and Data Analysis Division
         Office of Air Quality Planning and Standards
                     and
         Environmental Monitoring Systems Laboratory
           Office of Research and Development
         U.S. ENVIRONMENTAL PROTECTION AGENCY
         Research Triangle Park, North Carolina 27711


                 August 1984

-------
                               FOREWORD
     Many Individuals were involved in the preparation  of  this  document

and should be contacted if any questions arise in the application  of  the

guideline.
   Subject Area

Ambient Air Quality
 Monitoring

Meteorological
 Moni tori ng

Qua! ity Assurance
 (Ambient Air
  Quality)

PSD Policy and
 Interpretation
 of Regulations

Acceptable Methods
 Non-Criteria
 Pollutants
 Contact

Stan Sleva
David Lutz

James Dicke
Larry Purdue
Jack Puzak
Mike Trutna
Larry Purdue
Ken Rehme
 Phone Number
(Area Code 919)

    541-5651
    541-5651

    541-5681
    541-2665
    541-2188
    541-5591
    541-2665
    541-2666
FTS Number

 629-5651
 629-5651

 629-5681
 629-2665
 629-2188
 629-5591
 629-2665
 629-2666
                                        ii

-------
                                 LIST OF CHANGES
     The draft changes noted below have been made to incorporate the proposed
     regulatory changes.  EPA welcomes comments on these draft changes  only,
since the remainder of the guideline was subject to public  review in 1980.
The visibility section was also updated to reflect current  guidance published
since this guideline was printed.

 1.  Forward, page ii
     Current phone numbers are included.

 2.  Introduction, page 2
     New paragraph added for particulate matter.

 3.  Section 2.1.1, page 4
          added for listing of criteria pollutants.
 4.  Section 2.4.1(b), page 7
     Significant impact for PM^g added.

 5.  Section 2.4.4, page 9
     New section added for provisions for PM^g in transition period.

 6.  Old transition Section 2.5.2 for 1980 PSD regulations  deleted,  page 10.

 7.  Section 2.5.2, page 10
     New section added for transition period for PM^Q and  TSP.
 8.  Section 2.6(b) , page 13
     New section added for PM^g transition for non-reference methods.

 9.  Section 2.7, page 13
     Special sampling frequency added for PM^g.

10.  Section 3.3.2 page 23.
     New section added for new TSP siting criteria.

11.  Section 3.3.3, page 24
     New section added for siting criteria for PM^g  monitors.  Siting  criteria
     for other criteria pollutants were renumbered.

12.  Table 3, page 31
          included in revised table.
13.  Section 4, page 36
     Introduction revised to reflect quality assurance  requirements  for  lead
     have been promulgated, and also include

14.  Section 4.1.3.3, page 39
          added to title.
15.  Section 4.1.3.4, page 40
     Section revised to include
                                       iii

-------
                               Changes (Continued)
16.   Section 4.1.5, page 42
     Section revised to include

17.   Section 5.L, page 45
     New reference added in fifth paragraph.

18.   Section 5.2, page 48
     Visibility rule making updated.

19.   Section 6.1.1, page 49
     Uind direction system error changed to 5 degrees.

20.   Section 6.1.6, page 50
     Dewpoint temperature changed to  + 30°C.

21.   Section 6.1.10, page 51
     Visibility rule making updated.

22.   Section 7, page 52
     New reference added in last paragraph.

23.   Table A-l, page A-4
     Significant emissions rate added for PMig.

24.   Table A-2, page A-6
     Significant monitoring concentration added for

25.   Table A-3, page A-8
     Significant ambient air quality  impact added for PM^g and units corrected
     for CO.

26.   Appendix A, Section 3, Box 16, page A-18
          added.
27.  Appendix A, Section 3, Box 25, page A-21
          added.
28.  REFERENCES
     New references added for PM^g and others noted above, all  references
     renumbered as necessary.
                                        IV

-------
                                TABLE OF CONTENTS

                                                                        Page
1.  INTRODUCTION [[[     1
2.  GENERAL REQUIREMENTS AND CONSIDERATIONS- ..........................     3
    2.1  Monitoring Data Rationale ....................................     3
         2.1.1  Criteria Pollutants - Preconstruction  Phase -----------     3
         2.1.2  Criteria Pollutants - Postconstruction Phase ----------     4
         2.1.3  Noncriteria Pollutants - Preconstruction  and
                Postconstruction Phase --------------------------------     5
    2.2  Monitoring Objective and Data Uses — ....... ---------- ..... --     5
    2.3  VOC and 03 Monitoring Requirements ---------------------------     5
    2.4  Use of Representative Air Quality Data------- ----------------     6
         2.4.1  Monitor Location --------------------------------------     6
         2.4.2  Data Qual ity ................ - .........................     8
         2.4.3  Currentness of Data -----------------------------------     8
         2.4.4  Provisions for PMiQ and TSP in  Transition Period
                of 1985 PSD Regulations ...............................     9
    2.5  Duration of Monitoring ---------------------------------------     9
         2.5.1  Normal  Conditions -------------------------------------     9
         2.5.2  Transition Period for PM   and  TSP ....................   10
                2.5.2.1 Transition Within 10  Months  Ater  Promulgation-   10
                2.5.2.2 Transition During 10-16  Months  After
                        Promul gation ------------------ ...... --- -------   11
                2.5.2.3 Transition During 16-24  Months  After
                        Promulgation ----------------------------------   12
                2.5.2.4 Period Following 24 Months After  Promulgation-   12
    2.6  Sampling Methods and Procedures -------- ...... ----------------   13
    2.7  Frequency of Sampling ----------------------------------------   13
    2.8  Monitoring Plan ----------------------------------------------   14
    2.9  Meteorological  Parameters and  Measurement Methods ------------   14
3.  NETWORK DESIGN AND PROBE SITING CRITERIA ..........................   16
    3.1  Network Design -----------------------------------------------   16

-------
                      TABLE OF CONTENTS (Continued)
     3.2.1  Reconstruction Phase	    16
     3.2.2  Postconstruction Phase-	    18
     3.2.3  Special  Concerns for Location  of Monitors	    18

3.3  Probe Siting Criteria	-	-	   18

     3.3.1  Total Suspended Particulates (TSP)  (for  applications
            submitted before 6 months after promulgation)	   20

            3.3.1.1   Vertical  Placement	-	   20
            3.3.1.2   Spacing from Obstructions	   20
            3.3.1.3   Spacing from Roads	—	—   21
            3.3.1.4   Other Considerations	-	   21

     3.3.2  Total Suspended Particulates (TSP)  (for  applications
            submitted later than 6 months  after promulgation)	   23

            3.3.2.1   Vertical  Placement	-	   23
            3.3.2.2   Spacing from Obstructions-—	   23
            3.3.2.3   Spacing from Roads		   23
            3.3.2.4   Other Considerations	   24

     3.3.3  Particulate Matter (PMio)	   24

            3.3.3.1   Vertical  Placement	-	   24
            3.3.3.2   Spacing from Obstructions	   24
            3.3.3.3   Spacing from Roads	   25
            3.3.3.4   Other Considerations	   25

     3.3.4  Sulfur Dioxide (Stfc)	   25

            3.3.4.1   Horizontal  and Vertical Probe Placement	   25
            3.3.4.2   Spacing from Obstructions	   25

     3.3.5  Carbon Monoxide (CO)	-	   25

            3.3.5.1   Horizontal  and Vertical Probe Placement	   25
            3.3.5.2   Spacing from Obstructions	   26
            3.3.5.3   Spacing from Roads	   26

     3.3.6  Ozone (03)	   26

            3.3.6.1   Vertical  and Horizontal Probe Placement	   26
            3.3.6.2   Spacing from Obstructions	   26
            3.3.6.3   Spacing from Roads	   26

     3.3.7  Nitrogen Dioxide (N02)	-	   27

            3.3.7.1   Vertical  and Horizontal Probe Placement	   27
            3.3.7.2   Spacing from Obstructions—			   27
                                    vi

-------
                          TABLE OF CONTENTS (Continued)


                                                                        Page

         3.3.8  Lead (Pb)	-	—  27

                3.3.8.1  Vertical Placement	  27
                3.3.8.2  Spacing from Obstructions	  28
                3.3.8.3  Spacing from Roads	  28
                3.3.8.4  Other Considerations	-		  28

         3.3.9  Noncriteria Pollutants	  28

                3.3.9.1  Vertical Placement-	-	  28
                3.3.9.2  Spacing from Obstructions	  28
                3.3.9.3  Other Considerations	  29

    3.4  Probe Material and Pollutant Sample Residence Time	  29

    3.5  Summary of Probe Siting Requirements	  29

4.  QUALITY ASSURANCE FOR AIR QUALITY DATA	-----	  36

    4.1  Quality Assurance for Criteria Air Pollutants	  36

         4.1.1  General Information	  36

         4.1.2  Quality Control  Requirements	  37

                4.1.2.1  Organizational Requirements	  37
                4.1.2.2  Primary Guidance—		  37
                4.1.2.3  Pollutant Standards	  38
                4.1.2.4  Performance and System Audit Programs	  38

         4.1.3  Data Quality Assessment Requirements	  38

                4.1.3.1  Precision of Automated Methods	  38
                4.1.3.2  Accuracy of Automated Methods	  39
                4.1.3.3"  Precision of Manual Methods	  39
                4.1.3.4  Accuracy of Manual Methods	  40

         4.1.4  Calculations for Automated Methods	  41

                4.1.4.1  Single Analyzer Precision	  41
                4.1.4.2  Single Analyzer Accuracy	  42

         4.1.5  Calculations for Manual Methods	  42

                4.1.5.1  Single Instrument Precision for TSP,  Pb,
                         and PMio—	  42
                4.1.5.2  Single Instrument Accuracy for TSP and PMiQ—  43
                4.1.5.3  Single Instrument Sampling Accuracy for Pb	  43
                4.1.5.4  Single-Analysis-Day Accuracy for Pb	  43
                                       vn

-------
                          TABLE OF CONTENTS (Continued)

                                                                        Page

         4.1.6  Organization Reporting Requirements	   43

    4.2  Quality Assurance for Noncriteria Air Pollutants	   43

         4.2.1  Selection of Method-	   43
         4.2.2  Cal ibration		   44
         4.2.3  Data Validation	-	   44
         4.2.4  Standard and Split Samples	   44

5.  METEOROLOGICAL MONITORING	—	   45

    5.1  Data Required	   45

    5.2  Exposure of Meteorological  Instruments	   46

6.  METEOROLOGICAL INSTRUMENTATION	   49

    6.1  Specifications	   49

         6.1.1  Wind Systems (horizontal  wind)	   49
         6.1.2  Wind Systems (vertical  wind)	~	   49
         6.1.3  Wind Fluctuations-—	   49
         6.1.4  Vertical  Temperature  Difference	   50
         6.1.5  Temperature			   50
         6.1.6  Humidity	—	   50
         6.1.7  Radiation - Solar and Terrestrial	   50
         6.1.8  Mixing Height		-	-	   50
         6.1.9  Precipitation	   51
         6.1.10 Visibility	-	-   51

7.  QUALITY ASSURANCE FOR METEOROLOGICAL DATA	   52

8.  DATA REPORTING	-	—   53

    8.1  Air Quality Data Reporting	   53
    8.2  Meteorological Data Format  and Reporting	   53

APPENDIX A - PROCEDURES TO DETERMINE  IF MONITORING DATA  WILL BE
             REQUIRED FOR A PSD APPLICATION

1.  INTRODUCTION	A-l

2.  PSD PERMIT APPLICATION PROCEDURES	-	-	A-l
    2.1  Part 1 - Source Applicability Determination	A-l
    2.2  Part 2 - Pollutant Applicability Determination			A-3
    2.3  Part 3 - BACT Analysis	-	A-5
    2.4  Part 4 - Ambient Air Quality Analysis	A-5
    2.5  Part 5 - Source Impact Analysis	A-7
                                       viii

-------
                          TABLE OF  CONTENTS  (Continued)
    2.6  Part6 - Additional  Impact Analysis	A-7
    2.7  Part 7 - File Complete PSD Application		A-7

3.  DECISIONS FOR MONITORING  DATA  REQUIREMENTS	A-10

REFERENCES	A-23
                                        ix

-------
                              1.   INTRODUCTION
     The Clean Air Act Amendments of 1977,  Part D,  Prevention  of
Significant Deterioration, require that certain new major stationary
sources and major modifications be subject  to  a preconstruction review
which includes an ambient air quality analysis. Furthermore, the  Act
requires that an analysis be conducted in accordance with  regulations
promulgated by the EPA.  In this regard, the Agency promulgated PSD
regulations [1] on June 19, 1978, which included ambient monitoring
requirements.  Guidelines were published in May 1978 [2] to discuss
monitoring for PSD purposes.  However, in response  to the  June 18, 1979
preliminary Court Decision (Alabama Power Company v. Costle, 13 ERC
1225), EPA proposed revised PSD regulations L3J on  September 5, 1979.
The final court decision was rendered December 14,  1979  [4].   Based on
the public comments to the September 5, 1979 proposed PSD regulations
and the December 14, 1979 court decision, EPA  promulgated new  PSD regula-
tions on August 7, 1980.  Some of the pertinent provisions of  the 1980
PSD regulations that affect PSD monitoring  are discussed below:

     (a)  Potential  to emit.

          The PSD regulations retain the requirement that new  major
          stationary sources would be subject  to a  new source  review on
          the basis of potential to emit.  However, the  annual emission
          potential  of a source will  be determined  after the application
          of air pollution controls rather  than before controls as was
          generally done under the 1978 regulations [1].

     (b)  De minimi's cutoffs.

          The PSD regulations will exempt on a pollutant specific basis
          major modifications and new major stationary sources from all
          monitoring requirements when emissions of a particular  pollutant
          are below a specific significant  emission rate,  unless  the
          source is near a Class I area. Also included  are significant
          air quality levels which may be used to exempt sources  or
          modifications from PSD monitoring when the air quality  impacts
          from the sources or modifications are below specified values.

     (c)  Noncriteria pollutants.

          The 1978 PSD regulations [1] required monitoring only for those
          pollutants for which national  ambient air quality standards
          exist. However, there are a number of pollutants for which
          no ambient standards exist (noncriteria pollutants) but which
          are regulated under new source performance standards and
          national emission standards for hazardous pollutants.   The
          1980 regulations [5] require an ambient air quality  analysis
          for all  regulated pollutants emitted in significant  amounts.
          This analysis will generally be based on  modeling the impact
          of the pollutants in lieu of collecting monitoring data.

-------
     (d)  Preconstruction monitoring.

          A list of air quality concentrations  is  included  in the PSD
          regulations  as criteria  for  generally exempting proposed sources
          or modifications from collecting  monitoring  data.  Basically,
          monitoring data will  be  required  if the  existing air quality
          and the impact of the proposed  source or modification is equal
          to or greater than these concentrations.   In certain cases,
          even though  the air quality  impact or background  air quality
          may be less  than these concentrations, monitoring data may be
          required if  the proposed source or modification will impact a
          Class I area,  nonattainment  area,  or  area  where the PSD incre-
          ment is violated.

     (e)  Postconstruction monitoring.

          The PSD regulations include  authority to require postconstruc-
          tion monitoring.  In  general, EPA may require  postconstruction
          monitoring from large sources or  sources whose impacts will
          threaten standards or PSD increments.  The permit granting
          authority will  make this decision on  a case-by-case basis.

     On March 20, 1984,  [6] EPA proposed  revisions to  the National Ambient
Air Quality Stardards  (NAAQS) for  Particulate Matter.  Also, revisions
were proposed in 1984  [7] to revise the PSD regulations  to account for
the proposed NAAQS change.  The 1984 proposed PSD  revisions will not
require any new data gathering  requirements beyond the 1980 PSD require-
ments for PSD applications submitted prior  to 10 months  after promulgation
of the anticipated 1985  revised PSD regulations.   New monitoring require-
ments for PMio and TSP will be  phased  in  for PSD applications submitted
between 10 and 24 months after promulgation of  the 1985  revised PSD regu-
lations.  In addition, all new monitoring requirements for  PM^o and TSP
will be in effect 24 months after  promulgation.

     Because of the revisions to the PSD  regulations,  this guideline has
been modified to reflect such revisions.  The purpose  of this guideline
is to address those items or activities which are  considered essential in
conducting an ambient  air quality  monitoring program.  Guidance is given
for designing a PSD air quality monitoring  network as  well as the opera-
tional details such as sampling procedures  and  methods,  duration of
sampling, quality assurance procedures, etc. Guidance is also given for
a meteorological  monitoring program as well  as  the specifications for
meteorological instrumentation  and quality  assurance procedures.

     An appendix is included to show how  the ambient air quality analysis
fits in the overall PSD requirements.  Flow diagrams are presented to
aid a proposed source  or modification  in  assessing if monitoring data
may be required.

     General adherence to the guidance contained in  this document should
ensure consistency in  imp! ementi ng the PSD  monitoring  regulations.

-------
                  2.  GENERAL REQUIREMENTS AND  CONSIDERATIONS
2.1  Monitoring Data Rationale

     The court decision [4] has affirmed the Congressional  intent  in the
Clean Air Act as it relates to PSD monitoring requirements.   The court
ruled that section 165(e)(l) of the Clean Air Act requires  that an air
quality analysis be conducted for each pollutant  subject  to  regulation
under the Act before a major stationary source or major modification
could construct.  This analysis may be accomplished  by the use of  modeling
and/or monitoring the air quality.  EPA has  discretion in specifying the
choice of either monitoring or modeling, consistent  with  the provisions
in section 165(e)(2).  As will be discussed  later, modeling  will be used
in most cases for the analysis for the noncriteria pollutants.

     The court ruled that section 165(e)(2)  of the Clean  Air Act requires
that continuous preconstruction air quality  monitoring data  must be
collected to determine whether emissions from a source will  result in
exceeding the National  Ambient Air Quality Standards (NAAQS).  Further,
the data could be used to verify the accuracy of  the modeling estimates
since modeling will  be the principal  mechanism to  determine  whether
emissions from the proposed source or modification will result in  exceeding
allowable increments.  In regard to monitoring requirements,  the court
stated that EPA had the authority to exempt  de minimi's situations.

     Postconstruction monitoring data requirements are addressed in
section 165(a)(7) of the Clean Air Act.  Sources  may have to conduct
such monitoring to determine the air quality effect  its emissions  may
have on the area it impacts. EPA has the discretion  of requiring monitoring
data and the court stated that guidelines could be prepared  to show the
circumstances that may require postconstruction monitoring data.

     In view of the provisions of sections 165(e)(l), 165(e)(2), and
165(a)(7) of the Clean Air Act, the de mini mis concept, and  sections of
the final PSD regulations, Sections 771.1, 2.1.2  and 2.1.3 present the
basic rationale which generally will  be followed  to  determine when
monitoring data will  or will not be required.   It  should  be  noted  that
the subsequent use of "monitoring data" refers to  either  the use of
existing representative air quality data or  monitoring the existing air
qua!ity.

     Additional discussion and flow diagrams are  presented in Appendix A
of this guideline which show various decision  points leading  to a
determination as to when monitoring data will  or  will not be  required.
Also, these procedures indicate at what points a modeling analysis must
be performed.

2.1.1  Criteria Pollutants - Preconstruction Phase

     For the criteria pollutants (S02,  CO, and NOg)  continuous air quality
monitoring data must, in general, be used to establish existing air quality
concentrations in the vicinity of the proposed source or  modification.
For VOC emissions, continuous ozone monitoring data  must  be  used to

-------
establish existing air quality concentrations  in  the  vicinity  of  the
proposed source or modification.   For TSP,  PMig,  and  lead, the 24-hour
manual method will  be used to establish  the existing  air quality  concen-
trations.  However, no preconstruction monitoring data  will  generally be
required if the ambient air quality concentration before construction is
less than the significant monitoring concentrations.  (The significant
monitoring concentrations for each pollutant are  shown  in Table A-2 in
the appendix to this guideline.)  To require monitoring  data  where the air
quality concentration of a pollutant is  less than these values would be
questionable because these low level  concentrations cannot reasonably be
determined because of measurement errors.   These  measurement errors may
consist of errors in sample collection,  analytical measurement, calibra-
tion, and interferences.

     Cases where the projected impact of the source or  modification is
less than the significant monitoring concentrations would also generally
be exempt from preconstruction monitoring  data, consistent with the de
mini mis concept.  [40 CFR 51.24( i) (8) and  40 CFR  52.2K i) (8)].

     The one exception to the de minimi's exemption occurs when a  proposed
source or modification would adversely impact  on  a Class I area or would
pose a threat to the remaining allowable increment or NAAQS.  For those
situations where the air quality concentration before construction is
near the significant monitori.ng concentration, and there are uncertainties
associated with this air quality  situation, then  preconstruction  air
quality monitoring data may be required.  These situations must be
evaluated on a case-by-case basis by the permit granting authority
before a final decision is made.

2.1.2  Criteria Pollutants - Postconstruction  Phase

     EPA has discretion in requiring postconstruction monitoring  data
under section 165(a) (7) of the Clean Air Act and  in general will  not
require postconstruction monitoring data.   However, to  require air
quality monitoring data implies that the permit granting authority will
have valid reasons for the data and, in  fact,  will use  the data after it
is collected.  Generally, this will  be applied to large sources or
sources whose impact will threaten the standards  or PSD increments.
Examples of when a permit granting authority may  require postconstruction
monitoring data may include:

     a.   NAAQS are threatened - The postconstruction air quality is
projected to be so close to the NAAQS that monitoring is needed to
certify attainment or to trigger appropriate SIP  related actions  if
nonattainment results.

     b.   Source impact is uncertain or  unknown - Factors such as complex
terrain, fugitive emissions, and other uncertainties  in source or emission
characteristics result in significant uncertainties about the projected
impact of the source or modification. Postconstruction data is justified
as a permit condition on the basis that  model  refinement is  necessary to
assess the impact of future sources of a similar  type and configuration.

-------
2.1.3  Noncriten'a Pollutants - Preconstruct!'on and Postconstructlon Phase

     Consistent with section 165(e)(l)  of the  Clean Air  Act, EPA believes
that an analysis based on modeling of the impact of noncriteria pollutants
on the air quality should generally be  used  in lieu of monitoring data.
The permit granting authority,  however, does have the discretion of
requiring preconstruction and postconstruction monitoring data.  Before
a permit granting authority exercises its discretion in  requiring monitor-
ing data, there should be an acceptable measurement method approved by
EPA (see Section 2.6) and the concentrations would generally be equal
to or greater than the significant monitoring  concentrations (shown in
Table A-2 of the appendix).

     A permit granting authority may require monitoring  data in cases
such as (a) where a State or other jurisdiction has a standard for a
noncriteria pollutant and the emissions from the proposed source or
modification pose a threat to the standard,  (b) where the reliability of
emission data used as input to modeling existing sources is highly
questionable, especially for the pollutants  regulated under the national
emission standards for hazardous pollutants, and (c)  where available
models or complex terrain make  it difficult  to estimate  air quality or
impact of the proposed source or modification.

2.2  Monitoring Objective and Data Uses

     The basic objective of PSD monitoring is  to determine the effect
emissions from a source are having or may have on  the air quality in any
area that may be affected by the emission.  Principal  uses of the data
are as follows:

     (a)  To establish background air quality  concentrations in the
vicinity of the proposed source or modification.   These  background
levels are important in determining whether  the air quality before or
after construction are or will  be approaching  or exceeding the NAAQS or
PSD i ncrement.

     (b)  To validate and refine models.  The  data will  be helpful  in
verifying the accuracy of the modeling  estimates.

2.3  VOC and 03 Monitoring Requirements

     The previous 0.24 ppm nonmethane organic  compound (NMOC) standard,
which was used as a guide for developing State Implementation Plans to
attain the 03 ambient standard, has been rescinded.  However, VOC
emissions are the precursors in the formation  of ozone.  Consequently,
any new source or modified existing source located in an unclassified or
attainment area for ozone that  is equal  to or  greater than 100 tons per
year of VOC emissions will  be required  to monitor  ozone.  VOC monitoring
will not be required.

-------
2.4  Use of Representative Air Quality Data
     The use of existing representative  air  quality data was one of the
options discussed in Section 2.1 for monitoring  data.   In  determining
whether the data are representative, three major items  which need to be
considered are monitor location, quality of  the  data, and  currentness of
the data.

2.4.1  Monitor Location

     The existing monitoring data should be  representative of three
types of areas:  (1) the location(s) of  maximum  concentration increase
from the proposed source or modification, (2)  the  location(s) of the
maximum air pollutant concentration  from existing  sources, and  (3) the
location(s) of the maximum impact area,  i.e.,  where the maximum pollutant
concentration would hypothetically occur based on  the combined effect of
existing sources and the proposed new source or  modification.   Basically,
the locations and size of the three  types of areas are  determined through
the application of air qual ity model s.  The  areas  of maximum concentration
or maximum combined impact vary in size  and  are  influenced by factors
such as the size and relative distribution of  ground level and elevated
sources, the averaging times of concern, and the distances between impact
areas and contributing sources.

     In situations where there is no existing  monitor in the modeled
areas, monitors located outside these three  types  of areas may or may
not be used.  Each determination must be made  on a case-by-case basis.
In order to clarify EPA's intent regarding the use of existing
monitoring data, some examples are included  to demonstrate the overall
intent.

     (a)  Case I - If the proposed source or modification  will
be constructed in an area that is generally  free from the  impact of
other point sources and area sources associated  with human activities,
then monitoring data from a "regional" site  may  be used as representative
data.  Such a site could be out of the maximum impact area, but must be
similar in nature to the impact area.  This  site would  be characteristic
of air quality across a broad region including that in  which the proposed
source or modification is located.  The  intent of  EPA is to limit the
use of these "regional" sites to relatively  remote areas,  and not to use
them in areas of multisource emissions or areas  of complex terrain.

     (b)  Case II - If the proposed  construction will be in an area of
multi source emissions and basically  flat terrain,  then  the proposed
source or modification may propose the use of  existing  data at nearby
monitoring sites if either of the following  criteria are met.

          1.  The existing monitor is within 10  km of the  points of
proposed emissions, or

          2.  The existing monitor is within or  not farther than 1 km
away from either the area(s) of the  maximum  air  pollutant concentration
from existing sources or the area(s) of  the  combined maximum impact from
existing and proposed sources.

-------
          If the existing monitor(s)  meets  either of the  above two
conditions, the data could be used together with  the model estimates to
determine the concentrations at all  three types of areas  discussed
earlier in this section.

     As an example of the first criterion,  if  an  existing monitor is
located within 10 km from the points  of  proposed  emissions but not
within the boundaries of the modeled  areas  of  either of the three loca-
tions noted above, the data could be  used together with model estimates
to determine the concentrations at the three types of required area.

     The next example applies to the  second criterion.  In evaluating
the adequacy of the location of existing monitors, the applicant must
first, through modeling,  determine the significant ambient impact area
of the proposed source.  In general,  except for impact on Class I areas,
the application of air quality models for the  purpose of  determining
significant ambient impact would be limited to 50 km downwind of the
source or to that point where the concentration from the  source falls
below the levels shown in Table A-3 of the  Appendix.  For Class I areas,
a significant impact is 1  pg/nr (24-hr)  for PM^n,  TSP, and SOo.  The appli-
cant would then identify  within this  significant  impact area the area(s)
of the maximum air pollutant concentration  from existing  sources and the
area(s) of the combined maximum impact from existing and  proposed sources.
The area(s) of estimated maximum concentration from existing sources or
the estimated maximum combined impact area(s)  are  determined as follows:
First, within the modeled significant ambient  impact area, estimate the
point of maximum concentration from existing sources,  and the point of
combined maximum impact (existing and proposed source).   Using these
concentration values, determine the areas enclosed by air quality concen-
tration isopleths equal to or greater than  one half of the respective
estimated maximum concentration.   An  existing  monitor located within or
not farther than 1 km away from of any of these areas can yield represen-
tative data.

     The rationale for considering the use  of  existing data collected
from monitors satisfying  the above criteria is that modelers have a
reasonable degree of confidence in the modeling results within the 10 km
distance and the maximum  concentrations  from most  sources are likely
to occur within this distance.  Generally,  the modeling results in this
flat terrain case may under or over predict by a  factor of two, and thus
the actual maximum impact from the source(s) could occur  at points where
the model  predicts one half of this  impact.  Data  collected within or not
farther than 1 km from areas may be considered as  representative.

     (c)  Case III - If the proposed  construction  will be in an area of
multisource emissions and in areas of complex  terrain, aerodynamic downwash
complications, or land/water interface situations, existing data could
only be used for PSD purposes if it were collected (1) at the modeled
location(s) of the maximum air pollution concentration from existing
sources, (2) at the location(s) of the maximum concentration increase
from the proposed construction, and (3)  at  the location(s) of the maximum
impact area.  If a monitor is located at only  one  of the  locations mentioned
above and the locations do not coincide, the source would have to monitor
at the other locations.

-------
     It must be emphasized that the permit granting  authority may choose
not to accept data proposed under the  cases discussed  above.  This may
occur because of additional factors, especially in Case  II which were
not discussed but must be considered,  such as  uncertainties in data bases
for modeling and high estimates of existing air quality  resulting in
possible threats to the applicable standards.   Because of such situations,
the permit granting authority must review each proposal  on a case-by-case
basis to determine if the use of existing data will  be acceptable.  It
is important for the proposed source or modification to  meet with the
permit granting authority to discuss any  proposed use  of existing data.
If the data are not acceptable, then a monitoring program would have to
be started to collect the necessary data.

2.4.2  Data Quality

     The monitoring data should be of similar  quality  as would be obtained
if the applicant monitored according to the PSD requirements.  As a
minimum, this would mean:

     1.  The monitoring data were collected with continuous instrumentation,
         No bubbler data should be included.   See Section 2.4 for frequency
         of particulate pollutant sampling.

     2.  The applicant should be able  to  produce records of the
         quality control performed during the  time period at which
         the data were collected.   Such quality control  records should
         include calibration, zero and span checks,  and  control checks.
         In addition, quality control  procedures should  be a minimum
         specified in the instrument manufacturer's  operation and
         instruction manual.

     3.  Historical data that were gathered from monitors which were
         operated in conformance with  Appendix A or  B  of the Part 58
         regulations [8] would satisfy the quality assurance requirements.
             .. —. %
     4.  The calibration and span gases (for CO, S02 and N02) should
         be working standards certified by comparison  to a National
         Bureau of Standards gaseous Standard  Reference  Material.

     5.  The data recovery should be 80 percent of the data possible
         during the information effort.

2.4.3  Currentness of Data

     The air quality monitoring data should be current.  Generally, this
would mean for the preconstruction phase  that  the data must have been
collected in the 3-year period preceding  the permit  application, provided
the data are still  representative of current conditions.  When such data
are required, the noncriteria pollutant data must also have been collected
in the 3-year period preceding the permit application  provided that an
acceptable measurement method was used.  For the postconstruction phase,
the data must be collected after the source or modification becomes
operational.

-------
2.4.4  Provisions for PMjp and TSP  in Transition Period  of 1985 PSD Regulations

     Section 2.5.2 discusses the use of existing representative air quality
data for PIQ and TSP during the phasing in of  the 1985 PSD amendments for
particulate matter.  References are cited  for  using  existing nonreference
?MIQ and/or PMi5 data where available, or  TSP  data.   Existing representative
air quality data for PMio collected later  than 12 months after promulgation
of the 1985 PSD regulations must have been collected using reference or
equivalent PM^o method samplers.   Also, representative air quality data for
TSP collected later than 6 months after promulgation of  the 1985 PSD regula-
tions must have been collected using the siting criteria as discussed
in Section 3.3.2.

2.5  Duration of Monitoring

2.5.1  Normal Conditions

     If a source must monitor because representative air quality
data are not available for the preconstruction monitoring data requirement,
then monitoring generally must be conducted  for at least 1 year prior to
submission of the application to construct.  Also, if a  source decides to
monitor because representative air quality data are  not  available for the
postconstruction monitoring data requirement,  then monitoring must also be
conducted for at least 1  year after the source or modification becomes op-
erational.  However, under some circumstances, less  than 1 year of air
quality data may be acceptable for the preconstruction and postconstruction
phases.  This will  vary according to the pollutant being studied.  For all
pollutants, less than a full year will be  acceptable if  the applicant demon-
strates through historical  data or  dispersion  modeling that the data are
obtained during a time period when maximum air quality levels can be expected.
However, a minimum of 4 months of air quality  data will  be required.  As
discussed in Section 2.1.3, monitoring for noncriteria pollutants will
generally not be required.

     Special attention needs to be  given to  the duration of monitoring
for ozone.  Ozone monitoring will  still  be required  during the time
period when maximum ozone concentrations will  be expected.  Temperature
is one of the factors that affect ozone concentrations, and the maximum
ozone concentrations will generally occur  during the warmest 4 months of
the year, i.e., June-Sept ember.  However, historical monitoring data
have shown that the maximum yearly ozone concentration for some areas
may not occur from June-September.   Therefore, ozone monitoring will
also be required for those months when historical ozone  data have shown
that the yearly maximum ozone concentrations have occurred during months
other than the warmest 4 months of the year.   This requirement is in
addition to monitoring during the wannest 4 months of the year.  If
there is an interval of time between the wannest 4 months of the year
and month where historical  monitoring data have shown that the maximum
yearly ozone concentration has occurred, then  monitoring must also be
conducted during that interval.  For example,  suppose historical  data
have shown the maximum yearly ozone concentration for at least 1  year
occurred in April.   Also, suppose the warmest  4 months for that particular
area occurred June-September.  In such cases,  ozone  monitoring would be
required for April  (previous maximum concentration month), May (interval
month), and June-September (warmest 4 months).

-------
     Some situations may occur where a  source  owner  or operator may not
operate a new source or modification at the  rated capacity applied for
in the PSD permit.  Generally, the postconstruction  monitoring should
not begin until  the source is operating at a rate equal to or greater
than 50 percent of its design capacity.  However, in no case should the
postconstruction monitoring be started  later than 2  years after the
start-up of the new source or modification.

     If the permit granting authority has determined that less than 1
year of monitoring data is permissible, the  source must agree to use the
maximum values collected over this short period  for  comparison to all
applicable short-term standards,  and the average value for the short
period as the equivalent of the annual  standard.

     It should also be noted that the above  discussion of less than 1
year of data pertains to air quality data, not meteorological data. When
the air quality impact must be determined using  a dispersion model, the
preferred meteorological  data base is at least 1 year of on-site data.
Although less than 1 year of data may be sufficient  to determine the
acceptability for a model, once the model has  been accepted, a full year
of meteorological data must be used in  the PSD analysis.

2.5.2 Transition Period for PMip  and TSP

     The PSD regulatory changes for particulate  matter (PMio and Tsp)
[7] provide for a transition period for phasing  in the PM^g and TSP
monitoring data requirements.  The term "monitoring  data" was previously
defined in Section 2.1 as the use of existing  representative air quality
data or monitoring to determine the existing air quality.

2.5.2.1  Transition Within 10 Months After Promulgation - The first
provision of the regulations concerning a transition  period is in section
52.21(i)(ll)(i) and relates to applications  for  a PSD permit submitted
within 10 months after promulgation of  the 1985  PSD  amendments.  During
this 10-month period, the permit  granting authority  has the discretion of
waiving the preconstruction monitoring  data requirements for the ambient
air quality analysis discussed in Appendix A of  this guideline.  In all
cases no applicant would be required to initiate monitoring during this
period.  However, the requirement to use existing air quality data would
be discretionary.  The discretion would be based in  part on the availability
of existing air quality data which could include total suspended particulate
matter data, PM^o data, as well as inhalable particulate matter (PMis) data.
The PMi5 data would be from samplers with inlets designed for a 50 percent
collective efficiency at 15 ym.  The PMi5 data could be from dichotomous
samplers or high volume samplers  with a size selective inlet of 15 pm.

     (a)  Comparing Representative Air  Quality Data  to PMig NAAQS.
In situations where existing PMjo and/or PMis  data are available, the
data may be" used for describing the existing air quality levels for
comparison with the PM^Q NAAQS.   Reference [9] describes procedures for
estimating ambient PM]_Q concentrations  from PM]^ ambient air measurements.
The PM^ data multiplied by a correction factor  of 0.8 may be assumed to be
equivalent to PM^o-  Existing TSP data  may only  be used as a "one-for-one"
substitute for comparison to the  PM^Q NAAQS.
                                    10

-------
     Concerning the priorities for using  existing  air  quality data, the
first preference is to use ambient PM^o data.   The second preference is
to use inhalable particulate (PMis) measurements obtained with a dichoto-
mous sampler or a size selective high volume sampler.  The third preference
is to use total suspended particulte  (TSP) data.   Also, combinations of
the above data may be used.

     ( b)  Comparing TSP Representative Air Quality Data to TSP Secondary
NAAQS.  Existing TSP data may be used directly  for comparison to the TSP
secondary NAAQS during this period.   The  siting criteria described in
Section 3.3.1 would be used for these monitors.

2.5.2.2  Transition During 10-16 Months After Promulgation - The second
provision of the regulations concerning a transition period is in section
52.21(i)(ll)(ii) and relates to applications for a PSD permit submitted
between 10 and 16 months after promulgation  of  the regulations.  If pre-
construction monitoring data are required in the ambient air quality
analysis during this 10 to 16-month period,  the applicant must use repre-
sentative air quality data or collect monitoring data.

     (a)  Comparing P reconstruction Air Quality Data to PMjQ NAAQS.
Existing representative PM^o and/ or PM^s  air quality data may be used
if available.  The priorities and calculations  for using these data
were described in Section 2.5.2.1.  Existing TSP data cannot be used dur-
ing during this transition period.
     If the applicant collects  new PM^o  and/ or  PM^s monitoring data, the
data should have been collected from  the date 6 months after promulgation
of the 1985 PSD amendments  to the  time the  PSD  application becomes other-
wise complete.  The preferences for PMiQ  and PM^  data were previously
discussed.

     (b)  Comparing TSP P reconstruction  Air Quality Data to TSP NAAQS.
Existing representative TSP air quality  data may be used during this
period for comparision with the TSP secondary NAAQS.  These data, however,
must be from TSP monitors sited using the new criteria in Section 3.3.2.
If the applicant collects  new TSP  monitoring data, the TSP monitors must
also be sited using the new criteria in  Section 3.3.2.  When collecting
new monitoring data, the data should  have been  collected from the date 6
months after promulgation of the 1985 PSD amendments to the time the PSD
application becomes otherwise complete.

     (c)'  Other Considerations  and Explanations.   As discussed in Section
2.5.1, less than the maximum amount of data (10 months in this case) moni-
toring data will be acceptable  if  the applicant demonstrates, through
historical data or dispersion modeling,  that the data would be obtained
during a time period when the maximum air quality  can be expected.  The
minimum of 4 months of air  quality data  would still be required.  The
assumptions for the 10-month figure were  derived by assuming that 5 months
are needed for instrument  and equipment  procurement, 1 month to install
the equipment, calibrate and ensure satisfactory operation, and a minimum
of 4 months of monitoring data. The  upper  range of 16 months after promul
gation for use of non-reference PMio monitoring is based on the assumption
that within 11 months after promulgation, reference or equivalent method
samplers for PMio would be  designated by EPA and would be commercially
                                    11

-------
available.  Furthermore,  1 month  would  be  needed  to install the equipment,
calibrate, and ensure satisfactory operation, and a minimum of 4 months
would be needed for gathering monitoring data.

2.5.2.3  Transition During 16-24  Months After Promulgation - The third
transition period provision of the regulations  is in section 52.21(m)(l )( vii)
and relates to applications for a PSD permit submitted between 16 and 24
months after promulgation of the  regulations.   If preconstruction monitor-
ing data are required in  the ambient air quality analysis during this 16
to 24-month period, the applicant must  use representative air quality
data or collect monitoring data.
     (a)  Comparing Preconstruction Air Quality Data to PMio NAAQS.  .
If existing representative PMiq  and/ or PMis air quality data are available
they may be used.  The priorities  and calculations for using these data
were described in Section 2.5.2.1.  Existing TSP data cannot be used
during this transition period.   If no PMiQ or PM15 representative air
quality data are available,  the  applicant will have to collect monitoring
data using only reference or equivalent PMio method samplers.  The sampling
must be conducted for at least 12  months during the period from 12 months
after promulgation to the time when the application is completed, except
if the permit granting authority determines that a complete and adequate
analysis can be accomplished with  monitoring data'over a shorter period
(but in no case less than 4  months).

     (b)  Comparing TSP Preconstruction Air Quality Data to TSP NAAQS.
Existing representative TSP  air  quality data may be used during this
period for comparison with the TSP secondary NAAQS if sited using the new
criteria in Section 3.3.2.   If new PSD monitor! ng data are collected by
the applicant, the TSP monitors  must also be sited using the new criteria
in Section 3.3.2.  The TSP sampling must be conducted during the period
from 12 months after promulgation  to the time when the application is
completed, except if the permit  granting authority determines that a
complete and adequate analysis can be accomplished with monitoring data
over a shorter period (but in no case less than 4 months).'  "

2.5.2.4  Period Following 24 Months After Promulgation - For applications
for a PSD permit submitted later than 24 months after promulgation, the
transition period would no longer  be in effect.  If preconstruction mon-
itoring data are required in the ambient air quality analysis, the appli-
cant must use representative air quality data or collect monitoring data.

     (a)  Comparing Preconstruction Air Quality Data to PMio NAAQS.  If
existing representative PMio air quality data are available, they may be
used.  However, existing PMio representative air quality data collected
later than 24 months after the promulgation of the 1985 PSD amendments
must have been collected using reference or equivalent PMio method sam-
plers.  If no PMjo representative  air quality data are available, the
applicant will have to collect monitoring data using only reference or
equivalent PMio method samplers.
     (b)  Comparing TSP  Preconstruction Air Quality Data to TSP NAAQS.
Existing representative  TSP  air  quality data may be used for comparison
with the TSP secondary NAAQS if  sited  using the new criteria in Section
3.3.2.   If new PSD monitoring data are collected by the applicant, the
TSP monitors must also be sited  using  the  new criteria in Section 3.3.2.
                                   12

-------
2.6  Sampling Methods and Procedures

     (a)  Criteria pollutants.

          All ambient air quality monitoring must be  done  with  continuous
Reference or Equivalent Methods,  with the exception of  particulate matter
and lead for which continuous Reference or Equivalent Methods do  not exist.
For particulate matter and lead,  samples must be  taken  in  accordance with
the Reference Method.  The Reference Methods are  described in 40  CFR 50.
A list of designated continuous Reference or Equivalent Methods can be
obtained by writing Environmental  Monitoring Systems  Laboratory,  Department
E (MD-76),  U.S.  Environmental  Protection Agency,  Research  Triangle Park,
NC 27711.

     (b)  PMio Transition for Won- reference Methods
          As discussed in Section 2.5.2,  non- reference monitors  for  F*MIQ
may be used for applications submitted prior to 16 months  after  promulga-
tion of the 1985 PSD regulations.  These could include PMio  monitors as
well as inhalable particulate matter (PMis)  monitors.  The PMis  monitors
could be dichotomous monitors or high volume monitors with a size selec-
tive inlet of 15 pm.

     (c)  Noncriteria pollutants.

          For noncriteria pollutants, a list of acceptable measurement
methods is available upon request by writing Environmental Monitoring
Systems Laboratory, Quality Assurance Division (MD-77),  U.S. Environmental
Protection Agency, Research Triangle Park,  NC  27711.  This list  of accept-
able methods will be reviewed at least annually and  are  available from
the above address.  Measurement methods considered candidates  for the
noncriteria pollutant list should be brought to the  attention  of EPA at
the address given above.

2.7  Frequency of Sampling

     For all gaseous pollutants and for all  meteorological parameters,
continuous analyzers must be used.   Thus, continuous sampling  (over  the
time period determined necessary) is required.  For  particulate  pollu-
tants, except for PMio, daily sampling (i.e.,  one sample every 24 hours)
is required except in areas where the applicant can  demonstrate  that signi-
ficant pollutant variability is not expected.   In these  situations,  a
sampling schedule less frequent than every day would be  permitted.   However,
a minimum of one sample every 6 days will  be required for  these  areas.
The sampling frequency would apply to both preconstruction and postcon-
struction monitoring.
     The sampling frequency for PMio monitors is  determined  by  the
    , or TSP concentrations relative to the PMio  NAAQS.   The philosophy is
to use existing data where possible to determine  the  PMio  sampling  frequency.
The frequencies discussed below are consistent with the  Part 58 sampling
frequencies [6].  If PMio data are available but  not  from the locations as
specified in Section 2.4.1, then modeling could be used  in conjunction with
                                    13

-------
the data to estimate the PMio  concentrations  in  the  appropriate sampling
area(s) to determine the PMio  sampling  frequency.  If  these estimated concen-
trations were < 80 percent of the PMjQ  NAAQS,  then a minimum of one sample
every 6 days would be required for PM^Q  monitors; for  >80 - <90 percent of
the ?MIQ NAAQS, a minimum of one  sample  every other  day would be required;
and for >_90 percent of the PMiQ NAAQS every day  sampling would be required.
PMi5 data would be treated the same way  except the data must be multiplied
by a correction factor 0.8 to  be  equivalent to
     Reference [9] describes  how  TSP data* may  also be used to estimate the
probability of exceeding the  PMiQ NAAQS  in  the appropriate sampling area(s)
for purposes of determining the PMiQ sampling  frequency.  If the probabilities
are < .20 of the PMio NAAQS,  then a  minimum of one sample every 6 days would
be required for PMiQ monitors;  for >_. 20  - <.50 probabilities, a minimum of
one sample every other day would be  required;  and  for >_.50 probabilities,
every day sampling would be required.  These probability intervals are in
line with the percent of the  NAAQS intervals specified when using PMio data.
     In those cases where no  PMio,  PMi5,  or TSP data are  available to
determine the PM^Q sampling  frequency,  the PMiQ expected  concentrations
could be estimated by modeling.   These  estimated concentrations would be
used to calculate the percentage of the PMio  NAAQS and  the  resulting PMio
sampling frequency as discussed  above  for the cases where PMio data were
available.

2.8  Monitoring Plan

     A monitoring plan prepared  by  the  source should be submitted to and
approved by the permit granting  authority before any PSD monitoring
begins.  Note that approval  of the  monitoring plan before a monitoring
program is  started is not a  requirement.  However, since  the network
size and station locations are determined on  a case-by-case basis, it
would be prudent for the owner or operator to seek review of the network
and the overall monitoring plan  from the permit granting  authority prior
to collecting data.  This review could  avoid delays in the  processing of
the permit application and could also  result  in the elimination of any
unnecessary monitoring.   Delays  may result from insufficient, inadequate,
poor, or unknown quality data.  Table  1  lists the types of  information
that should be included in the monitoring plan.

2.9  Meteorological Parameters and  Measurement Methods

     Meteorological data will  be required for input to dispersion models
used in analyzing the impact of the proposed  new source or modification
on ambient air quality and the analyses  of effects on soil, vegetation,
and visibility in the vicinity of the  proposed source.  In  some cases,
representative data are available from  sources such as the  National
Weather Service.  However, in some  situations, on-site data collection
will be required.  The meteorological monitoring and instrumentation
considerations are discussed in  Sections 5 and 6.
                                    14

-------
             TABLE 1.  MINIMUM CONTENTS OF A MONITORING  PLAN


     SOURCE ENVIRONMENT DESCRIPTION (within 2 km of source)

        topographical description
        land-use description
        topographical map of source and environs (including location  of
        existing stationary sources, roadways,  and  monitoring  sites)
        climatological description
        quarterly wind roses (from meteorological  data collected  at the
        source or other representative meteorological data)

II.  SAMPLING PROGRAM DESCRIPTION

     •  time period for which the pollutant(s)  will  be measured
     •  rationale for location of monitors (incl ude modeling results  and
        analysis of existing soures in the area)
     •  rationale for joint utilization of monitoring network  by  other
        PSD sources

III. MONITOR SITE DESCRIPTION                   "   "

        Universal Transverse Mercator (UTM) coordinates
        height of sampler (air intake)  above ground
        distance from obstructions and heights  of obstructions
        distance from other sources (stationary and mobile)
        photographs of each site (five photos:  one  in each cardinal direc-
        tion looking out from each existing sampler or where a future
        sampler will be located, and one closeup of each existing sampler
        or where a future sampler will  be located.   Ground cover  should be
        included in the closeup photograph.)

IV.  MONITOR DESCRIPTION

     •  name of manufacturer
     t  description of calibration system to be used
     •  type of flow control  and flow recorder

V.   DATA REPORTING

     •  format of data submission
     t  frequency of data reporting

VI.  QUALITY ASSURANCE PROGRAM

     t  calibration frequency
     •  independent audit program
     •  internal qua!ity control procedures
     •  data precision and accuracy calculation procedures
                                    15

-------
                 3.  NETWORK DESIGN AND PROBE SITING  CRITERIA

     A source subject to PSD should proceed with designing  a PSD monitoring
network only after going through the procedure in Appendix  A to determine
if monitoring data will  be required.   To fulfill  that requirement, a  source
may use representative air quality data which was discussed in Section  2.4
or monitor.  This section presents guidance to be used if an applicant
decides to monitor in lieu of using representative air quality data.

3.1  Network Design

     The design of a network for criteria and noncriteria pollutants
will be affected by many factors, such as topography, climatology,
population, and existing emission sources.  Therefore, the  ultimate
design of a network for  PSD purposes must be decided  on a case-by-case
basis by the permit granting authority.  Section 3.2  discusses the number
and location of monitors for a PSD network.   Additional guidance on the
general siting of the monitors may be found in references 10-14 which
discuss highest concentration stations, isolated point sources, effects
of topography, etc.  Probe siting criteria for the monitors are discussed
in Section 3.3. The guidelines presented here should  be followed to the
maximum extent practical in developing the final  PSD  monitoring network.

3.2  Number and Location of Monitors

     The number and location of monitoring sites will  be determined on a
case-by-case basis by the source owner or operator and reviewed by the
permit granting authority.  Consideration should be given to the effects
of existing sources, terrain, meteorological  conditions, existence of
fugitive or reentrained  dusts, averaging time for the pollutant, etc.
Generally, the number of monitors will  be higher where the  expected
spatial variability of the pollutant in the area(s) of study is higher.

3.2.1  Preconstruction Phase

     Information obtained in the ambient air quality  analysis in Appendix
A will be used to assist in determining the number and location of monitors
for the preconstruction  phase.  The air quality levels before construction
were determined by modeling or in conjunction with monitoring data.  The
screening procedure (or  more refined model)  estimates were  determined in
Appendix A.

     The source should first use the screening procedure or refined model
estimates to determine the general  location(s)  for the maximum air quality
concentrations from the  proposed source or modification.  Secondly, the
source should determine  by modeling techniques  the general  location(s)
for the maximum air quality levels from existing sources.   Thirdly, the
modeled pollutant contribution of the proposed  source or modification
should be analyzed in conjunction with the modeled results  for existing
sources to determine the maximum impact area.   Application  of these
models must be consistent with EPA's "Guideline on Air Quality Models"
[15]. This would provide sufficient information for the applicant to
place a monitor at (a) the location(s)  of the maximum concentration
                                    16

-------
increase expected from the proposed source  or modification,  (b) the
location(s) of the maximum air  pollutant concentration  from  existing
sources of emissions, and (c)  the location(s) of  the maximum  impact area,
i.e., where the maximum pollutant concentration would hypothetically
occur based on the combination  effect of existing sources and  the pro-
posed new source or modification.   In some  cases,  two or more  of these
locations may coincide and thereby reduce the number of monitoring
stations.

     Monitoring should then be  conducted in or as close to these areas
as possible (also see discussion  in Section 3.2.3).  Generally, one to
four sites would cover most situations in multisource settings.  For
remote areas in which the permit  granting authority has determined that
there are no significant existing sources,  a minimum number  of monitors
would be needed, i.e., one or  probably two  at the most.  For new sources,
in these remote areas, as opposed to modifications, some concessions will
be made on the locations of these monitors.  Since the  maximum impact
from these new sources would be in remote areas,  the monitors  may be
located, based on convenience  or  accessibility, near the proposed new
source rather than near the maximum impact  area since the existing air
quality would be essentially the  same in both areas.  However, the maximum
impact area is still the preferred location.

     When industrial process fugitive particulate emissions are involved,
the applicant should locate a monitor at the proposed source site (also
see Section 3.2.3).  If stack  emissions are also  involved, a downwind
location should also be selected.  For fugitive hydrocarbon  emissions,
the applicant should locate a monitor downwind of the source at the point
of expected maximum ozone concentration contribution.   This  location will
be found downwind during conditions that are most conducive to ozone for-
mation, such as temperature above 20°C (68°F) and high  solar radiation
intensity.  For hydrocarbon emissions from  a stack, the applicant should
also locate the monitor in the area of expected maximum ozone  concentra-
tion.  For both fugitive and stack emissions, the selection of areas of
highest ozone concentrations will  require wind speed and direction data
for periods of photochemical  activity.  Monitoring for  ozone will only be
necessary during the seasons when high concentrations occur.

     Since ozone is the result  of a complex photochemical process, the
rate of movement across an area of the air  mass containing precursors
should be considered.  The distance from the proposed source to the
monitor for an urban situation  should be about equal to the  distance
traveled by the air moving for 5  to 7 hours at wind speeds occurring
during periods of photochemical  activity.   In an  urban  situation, ozone
formation over the initial  few hours may be supressed by nitric oxide
(NO) emissions.  For a point source, the NO interactions may be minimal,
and the travel time to the expected maximum ozone  concentration may be 3
to 4 hours downwind.  In general, the downwind distance for  the maximum
ozone site should generally not be more than 15 to 20 miles  from the
source because a lower wind speed (2-3 miles per  hour)  with  less dilution
would be a more critical case.  Additionally, the frequency that the
wind would blow from the source over the site diminishes with  increasing
distances.
                                    17

-------
3.2.2  Postconstruction Phase

     As discussed above for preconstruction  monitoring,  appropriate dis-
persion modeling techniques are used  to  estimate  the  location of the
air quality impact of the new source  or  modification. Monitors should
then be placed at (a) the expected area  of the maximum concentration
from the new source or modification,  and (b)  the  maximum impact area(s),
i.e., where the maximum pollutant concentration will  occur based on the
combined effect of existing sources and  the  new source or modification.
It should be noted that locations for these  monitors  may be different
from those sites for the preconstruction phase due  to other new sources
or modifications in the area since the preconstruction monitoring.

     Generally, two or three sites would be  sufficient for most situations
in multisource areas.  In remote areas where there  are no significant
existing sources, one or two sites would be  sufficient.   These sites
would be placed at the locations indicated from the model results.  The
same concerns discussed in Section 3.2.1 regarding  industrial process
fugitive particulate emissions, fugitive hydrocarbon  emissions, and ozone
monitoring would also be applicable for  the  postconstruction phase.

3.2.3  Special Concerns for Location  of  Monitors

     For the preconstruction and postconstruction phases, modeling is
used to determine the general  area where monitors would  be located. Some
of the modeled locations may be within the confines of the source's bound-
ary.  However, monitors should be placed in  those locations satisfying
the definition of ambient air.  Ambient  air  is defined in 40 CFR 50.1(e)
as "that portion of the atmosphere, external  to buildings, to which the
general public has access."  Therefore,  if the modeled locations are
within an area excluded from ambient  air, the monitors should be located
downwind at the boundary of that area.

     In some cases, it is simply not  practical to place  monitors at the
indicated modeled locations.  Some examples  may include  over open bodies
of water, on rivers, swamps, cliffs,  etc.  The source and the permit
granting authority should determine on a case-by-case basis alternative
locations.

3.3  Probe Siting Criteria

     The desire for comparability in  monitoring data  requires adherence
to some consistent set of guidelines.  Therefore, the probe siting cri-
teria discussed below must be followed to the maximum extent possible
to ensure uniform collection of air quality  data  that are comparable and
compatible.

     Before proceeding with the discussion of pollutant  specific probe
siting criteria, it is important to expand on the discussion in Section
3.2 of the location of monitors.  In  particular,  reference is made to
two monitoring objectives.

     •  Case 1:  Locating monitors to determine the maximum concentration
                 from the proposed source and/or  existing sources.
                                    18

-------
     •  Case 2:  Locating monitors to determine where the combined
                 impact of the proposed source  and  existing  sources
                 would be expected to exhibit the highest concentrations.

     For Case 1, the driving force for locating the siting area of the
monitor as well as the specific location of the probe or  instrument  shelter
is the objective of measuring the maximum impact from the proposed source.
Two Case 1 examples are given.  Consider the first  situation in which a
proposed source would be emitting pollutants from an elevated  stack.  Under
these circumstances, sufficient mixing generally occurs during the transport
of the emissions from the stack to the ground resulting in small vertical
gradients near ground level, thus, a wide range of  probe  heights, 3-15 meters
for gases and 2-15 meters for particulates  is acceptable.  For the same
objective (maximum concentration from proposed  source), consider the second
example in which pollutants would be emitted from a ground level source.
In this case, the concentration gradient near the ground  can be large,
thereby requiring a much tighter range of acceptable probe heights.  For
ground level sources emitting pollutants with steep vertical  concentration
gradients, efforts should be made to locate the inlet probe  for gaseous
pollutant monitors as close to 3 meters (a  reasonable practical represen-
tation of the breathing zone) as possible and for particulate  monitors
using the hi-volume sampler 2 to 7 meters above ground level.  The ration-
ale for the 3 meters is that for gaseous pollutant  measurements, the inlet
probe can be adjusted for various heights even  though the monitor is loca-
ted in a building or trailer.  On the contrary, the 2-3 meter  height for
the hi-volume sampler placement is not practical  in certain  areas.   The 7
meter height allows for placement on a one  story building and  is reasonably
close to representing the breathing zone.

     Turn now to the second monitoring objective, Case 2, which is
locating monitors to determine the maximum  impact area taking  into consid-
eration the proposed source as well  as existing sources.  The  critical
element to keep in mind in locating a monitor to satisfy  this  objective
is that the intent is to maximize the combined  effect.  Thus,  in one
circumstance, the existing source might contribute  the largest impact.
The importance of the above discussion to the topic of probe siting  cri-
teria is that in attempting to locate a monitor to  achieve this objective,
the placement of the probe or instrument shelter can vary depending  upon
which source is the predominant influence on the maximum  impact area.  As
an extreme example, consider the situation  where a  proposed  elevated
source would emit CO into an urban area and have maximum  combined CO
impact coincident to an area adjacent to a  heavily  traveled  traffic
corridor.  It is known that traffic along corridors emit  CO  in fairly
steep concentration gradients so the placement  of the probe  to measure
the areas of highest CO concentration can vary  significantly with probe
height as well  as distance from the corridor.  In this example, the
traffic corridor has the major influence on the combined  impact and
therefore controls the probe placement.   As noted in the  CO  probe siting
criteria in Section 3.3.3 as well as Appendix E of  the May 10, 1979
Federal Register promulgation of the Ambient Air Monitoring  Regulations
L8J, the required probe height in such microscale cases is given as  3 +_
1/2 meters while the distance of the probe  from the roadway  would be
between 2 and 10 meters.
                                    19

-------
     As another example, consider the case where  the  same  proposed CO
source would emit CO at elevated heights  and  have a combined maximum CO
impact in an urban area that is only slightly affected  by  CO emissions
from a roadway.  The combined impact area in  this case  is  far enough
away from the two sources to provide adequate mixing  and only small
vertical  concentration gradients at the  impact area.   In this case, the
acceptable probe height would be in the  range of  3-15 meters.

     It is recognized that there may be other situations occurring which
prevent the probe siting criteria from being  followed.  If so, the
differences must be thoroughly documented.  This  documentation should
minimize future questions about the data.

     The desire for comparability in monitoring data  requires adherence
to some consistent set of guidelines. Therefore, the probe siting
criteria discussed below must be followed to  the  maximum extent possible
to ensure uniform collection of air quality data  that are  comparable and
compatible.   To achieve this goal,  the specific siting  criteria that are
prefaced with a "must" are defined as a  requirement and exceptions must
be approved by the permit granting  authority.   However, siting criteria
that are prefaced with a "should" are defined as  a goal to meet for
consistency, but are not a requirement.

3.3.1  Total Suspended Particulates (TSP)

     Section 3.3.1 is applicable only for the following cases.  PSD
applications submitted before the date 6  months after promulgation of the
1985 PSD regulations would use this siting  criteria when collecting TSP
monitoring data.  Also, representative air quality data for TSP collected
before the date 6 months after promulgation of the 1985 PSD regulations
could use this siting criteria.  For both cases above,  data collected
after the 6  month date would use the TSP  siting criteria described in
Section 3.3.2.

3.3.1.1  Vertical Placement - The most desirable  height for a TSP monitor
is near the  breathing zone.   However, practical considerations such as
prevention of vandalism, security,  accessibility, availability of electri-
city, etc.,  generally require that  the sampler be elevated.  Therefore,
a range of acceptable heights needs to be used.  In addition, the type
of source, i.e., elevated or ground level,  predominantly influencing the
area of impact must be considered when locating the monitor.  For purposes
of determining elevated source impact, the  sampler air intake must be
located 2-15 meters above ground level.   The  lower limit was based on a
compromise between ease of servicing the  sampler  and the desire to avoid
reentrainment from dusty surfaces.   The upper limit represents a compromise
between the  desire to have measurements which  are most representative of
population exposures, and the considerations  noted earlier.  For ground
level sources with steep vertical concentration gradients, the air
intake must be as close to the breathing  zone as  practical.

3.3.1.2  Spacing from Obstructions  - If the sampler is located on a roof
or other structure, then there must be a  minimum  of 2 meters separation
from walls,  parapets, penthouses, etc.  Furthermore, no furnace or
incineration flues should be nearby.  The separation distance from flues
is dependent on the height of the flues,  type  of waste or  fuel  burned,
                                    20

-------
and quality of the fuel  (ash  content).   For  example, if the emissions
from the chimney are the result  of  natural gas combustion, no special
precautions are necessary except for  the avoidance of obstructions,
i.e., at least 2 meters  separation.   On  the  other hand, if fuel oil,
coal, or solid waste is  burned and  the stack is  sufficiently short so
that the plume could reasonably  be  expected  to impact on the sampler
intake a significant part of  the time, other buildings/locations in the
area that are free from  these types of sources should be considered for
sampling.  Trees provide surfaces for particulate deposition and also
restrict airflow.  Therefore, the sampler should be placed at least 20
meters from trees.

     Obstacles such as buildings must also be avoided so that the distance
between obstacles and the sampler is  at  least twice the height that the
obstacle protrudes above the  sampler. In addition, there must be unre-
stricted airflow in an arc of at least 270°  around the sampler, and the
predominant direction for the season  of  greatest pollutant concentration
potential must be included in the 270° arc.

3.3.1.3  Spacing from Roads - A  number of studies [16-23] support the
conclusion that particulate concentrations decrease with increasing
height of the monitor and distance  from  the  road.  Quite high concentra-
tions have been reported at monitors  located  at a low elevation close to
heavily traveled roads.   Moreover,  monitors  located close to streets are
within the concentrated  plume of particulate  matter emitted and generated
by vehicle traffic.  Therefore,  ambient  monitors for TSP should be located
beyond the concentrated  particulate plume generated by traffic, and not
so close that the heavier reentrained roadway particles totally dominate
the measured ambient concentration.

     An analysis of various monitoring studies [24] shows that a linear
relationship between sampler  height and  distance from roadways defines a
zone where the plume generated by traffic greater than approximately 3,000
vehicles per day is diminished.   Figure  1  illustrates this relationship
by showing two zones where TSP monitors  could be located.  Zone A repre-
sents locations which are recommended and Zone B represents locations
which should be avoided  in order to minimize  undesirable roadway influen-
ces.  Roads with lower traffic (less  than approximately 3,000 vehicles
per day) are generally not considered to be  a major source or vehicularre-
lated pollutants, and so as noted in  Figure  1 do not preclude the use of
monitors in Zone B for those  situations.  However, note that for those
cases where the traffic  is less  than  approximately 3,000 vehicles per
day, the monitor must be located greater than 5 meters from the edge of
the nearest traffic lane and  2 to 15  meters  above ground level.

     In the case of elevated  roadways where  the monitor must be placed
below the level of the roadway,  the monitor  should be located no closer
than approximately 25 meters  from the edge of the nearest traffic lane.
This separation distance applies for  those situations where the road is
elevated greater than 5  meters above  the ground level, and applies to
all traffic volumes.

3.3.1.4  Other Considerations -  Stations should not be located in an
unpaved area unless there is  vegetative  ground cover year round so that
the impact of reentrained or  fugitive dusts  will be kept to a minimum.
Additional  information on TSP probe siting may be found in reference 10.
                                    21

-------
                                     ZONE C (UNACCEPTABLE)
                                                    ZONE A (ACCEPTABLE)
               ZONE U (NOT RECOMMENDED)
                        10                     20          25          30
                         DISTANCE FROM EDGE OF NEAREST TUAPriC LANE, molor»a
"APPLIES WHERE ADT >3 000
                           Figure 1.  Acceptable zone for sitiny TSP monitors

-------
3.3.2  Total Suspended Particulates  (TSP)

     The siting criteria  for TSP  in  this section is applicable for PSD
applications submitted later than 6  months  after the promulgation of the
1985 PSD regulations.

3.3.2.1  Vertical  Placement -  Practical considerations such as prevention
of vandalism, security, accessibility,  availability of electricity, etc.,
generally require  that a  TSP sampler be elevated rather than at ground
level.   Therefore, a range  of  acceptable heights needs to be used..  In
addition, the type of source,  i.e.,  elevated or ground level, predominantly
influencing the area of impact must  be considered when locating the mon-
itor.  Therefore,  the sampler  for measuring maximum impact from ground
level sources must be 2-7 meters  above ground level unless it can be shown
that maximum concentrations exist at higher elevations.  Samplers located
to monitor for elevated sources are  allowed a wider range of heights for
locating the air inlet of the  monitor.  For TSP samplers, the acceptable
range for monitoring emissions from  elevated sources is 2-15 meters.

3.3.2.2  Spacing from Obstructions - If the sampler is located on a roof
or other structure, then  there must  be  a minimum of 2 meters separation
from walls, parapets, penthouses, etc.  Furthermore, no furnace or incin-
eration flues should be nearby.   The separation distance from flues is
dependent on the height of  the flues, type  of waste or fuel burned, and
quality of the fuel (ash  content).   For example, if the emissions from
the chimney are the result  of  natural gas combustion, no special precau-
tions are necessary except  for the avoidance of obstructions, i.e., at
least 2 meters separation.   On the other hand, if fuel oil, coal, or
solid waste is burned and the  stack  is  sufficiently short so that the
plume could reasonably be expected to impact on the sampler intake a
significant part of the time,  other  buildings/locations in the area that
are free from these types of sources should be considered for sampling.
Trees provide surfaces for  particulate  deposition and also restrict
airflow.  Therefore, the  sampler  should be  placed at least 20 meters from
trees.

     Obstacles such as buildings  must also  be avoided so that the distance
between obstacles  and the sampler is at least twice the height that the
obstacle protrudes above the sampler.  In addition, there must be unre-
stricted airflow in an arc  of  at  least 270° around the sampler, and the
predominant direction for the  season of greatest pollutant concentration
potential must be  included  in  the 270° arc.

3.3.2.3  Spacing from Roads -  A number  of studies [16-23] support the
conclusion that particulate concentrations  decrease with increasing height
of the monitor and distance from  the road.  Quite high concentrations
have been reported at monitors located at a low elevation close to heavily
traveled roads.  Moreover,  monitors  located close to streets are within
the concentrated plume of particulate matter emitted and generated by
vehicle traffic, thus to  determine the  impact of TSP from motor vehicles,
it is desirable to locate the  sampler near  the roadway.

     An analysis of various monitoring  studies [24] shows that a linear
relationship between sampler height  and distance from roadways defines a
zone where the plume generated by traffic greater than approximately
3,000 vehicles per day is diminished.   To determine the combined impact

                                    23

-------
of TSP from a proposed source and motor vehicles,  it is  desirable  for the
TSP monitors to be located in the enhanced portion of the  plume.   For
those situations where the emissions from a proposed source  would  impact
close to a roadway, the air intake of the monitor  must be  located  5-15
meters from the edge of the nearest traffic lane.   Also  for  these  situa-
tions, the air intake must be 2-7 meters above ground level.

3.3.2.4  Other Considerations -  Stations should not be  located  in an
unpaved area unless there is vegetative ground cover year  round  so that
the impact of reentrained or fugitive dusts will be kept to  a minimum.
Additonal information on TSP probe siting may be found in  reference 10.

3.3.3  Particulate Matter
3.3.3.1.  Vertical Placement - Although there are  limited  studies on
the PMio concentration gradients around roadways or  other  ground level
sources, references 16, 17,  19, 25,  and 26  show a  distinct variation in
the distribution of TSP and  Pb levels  near  roadways.  TSP, which is greatly
affected by gravity, has large concentration  gradients, both horizontal
and vertical, immediately adjacent to  roads.   Pb,  being predominantly sub-
micron in size, behaves more like a  gas and does not exhibit steep vertical
and horizontal  gradients as  does TSP.   PM^o,  being intermediate in size
between these two extremes exhibits  dispersion properties  of both gas and
settleable particulates and  does show  vertical  and horizontal gradients
[27].   Similar to monitoring for other pollutants, optimal placement of the
sampler inlet for PMio monitoring should be at breathing height level.  How-
ever, practical factors such as prevention  of vandalism, security, and safety
precautions must also be considered  when siting a  PMio monitor.  Given these
considerations, the sampler  inlet for  ground  level source  monitoring must be
2-7 meters above ground level.  For  PMio samplers, the acceptable range for
monitoring emissions from elevated  sources  is 2-15 meters  above ground level.

3.3.3.2  Spacing from Obstructions  - If the sampler  is located on a roof
or other structure, then there must  be a minimum of  2 meters separation
from walls, parapets, penthouses, etc.   No  furnace or incineration flues
should be nearby.  This separation distance from flues is  dependent on
the height of the flues, type of waste or fuel  burned, and quality of the
fuel (ash content).  In the  case of  emissions from a chimney resulting
from natural  gas combustion, the sampler should be placed, as a precaution-
ary measure, at least 5 meters from  the chimney.

     On the other hand, if fuel  oil, coal,  or solid  waste  is burned and
the stack is sufficiently short so that the plume  could reasonably be
expected to impact on the sampler intake a  significant part of the time,
other buildings/locations in the area  that  are free  from these types
of sources should be considered for  sampling.   Trees  provide surfaces
for particulate deposition and also  restrict  airflow.  Therefore, the
sampler should be placed at  least 20 meters from trees.

     The sampler must also be located  away  from obstacles  such as buildings,
so that the distance between obstacles  and  the  sampler is  at least twice
the height that the obstacle protrudes above  the sampler.  There must
also be unrestricted airflow in an arc  of at  least 270° around the sampler,
and the predominant wind direction for the  season  of greatest pollutant
concentration potential  must be included in the 270° arc.
                                    24

-------
3.3.3.3  Spacing from Roads -  For these  situations where the emissions
from a proposed source would impact  close  to a  roadway, the air intake
for the monitor must be located between  5-15 meters  from the edge of the
nearest traffic lane.   Monitors located  in  this area would thus measure
the combined impact from the proposed source and  the roadway.  The sampler
air intake must be 2-7 meters  above  ground  level.

3.3.3.4  Other Considerations  - Stations should not  be located in an
unpaved area unless there is vegetative  ground cover year round so that
the impact of reentrained or fugitive dusts will  be  kept to a minimum.
Additional information on PMio siting may  be found in reference 28.

3.3.4  Sulfur Dioxide ($02)

3.3.4.1.  Horizontal and Vertical Probe  Placement - As with TSP monitoring,
the most desirable height for  an S02 inlet  probe  is near the breathing
height.  Various factors enumerated  before  may  require that the inlet
probe be elevated,  consideration must also be  given to the type of source
predominantly influencing the  impact area.  For elevated sources, the inlet
probe must be located 3 to 15  meters above ground level.  For ground
level sources, locate as close to the breathing zone as possible.  If the
inlet probe is located on the  side of the  building,  then it should be
located on the windward side of the  building relative to the prevailing
winter wind direction.  The inlet probe  must also be located more than 1
meter vertically or horizontally away from  any supporting structure and
also away from dirty, dusty areas.

3.3.4.2  Spacing from Obstructions -  No furnace  or  incineration flues,
or other minor sources of S02  should be  nearby.   The separation distance
is dependent on the height of  the flues, type of  waste or fuel burned,
and the quality of the fuel (sulfur  content).   If the inlet probe is
located on a roof or other structure, it must be  at  least 1 meter from
walls, parapets, penthouses, etc.

     The inlet probe should.be placed more  than 20 meters from trees and
must be located away from obstacles  and  buildings.  The distance between
the obstacles and the inlet probe must be  at least twice the height that
the obstacle protrudes above the inlet probe.   Airflow must also be unre-
stricted in an arc of at least 270°  around  the  inlet probe, and the pre-
dominant direction for the season of greatest pollutant concentration
potential must be included in  the 270° arc. If the probe is located on
the side of a building, 180° clearance is  required.  Additional information
on S02 probe siting criteria may be  found  in reference 11.

3.3.5  Carbon Monoxide (CO)

3.3.5.1  Horizontal and Vertical Probe Placement  - Because of the importance
of measuring population exposure to  CO concentrations, optimum CO sampling
should be done at average breathing  heights.  However, practical factors
require that the inlet probe be higher.  In general, for CO emitted at
elevated heights, the inlet probe for CO monitoring  should be 3-15 meters
above ground level.  For those situations  where the  emissions from a pro-
posed source would impact a street canyon  or corridor type area in an
urban area, and the area is predominantly  influenced by the traffic from
the street canyon or traffic corridor, the  inlet  probe should be positioned
3 _+ 1/2 meters above ground level which  coincides with the vertical probe


                                    25

-------
placement criteria for a street canyon/corridor  type  site [8].  The
criteria is more stringent than the 3 to  15 meter  range specified earlier
because CO concentration gradients resulting  from  motor vehicles traveling
along street canyon or corridors are rather steep  and show wide variations
in CO levels at different heights.  The 3 meter  height is a compromise
between breathing height representation and such factors as the prevention
of obstructions to pedestrians, vandalism, etc.

     In addition to the vertical  probe criteria, the  inlet probe must
also be located more than 1  meter in the  vertical  or  horizontal direction
from any supporting structure.

3.3.5.2  Spacing from Obstructions - Airflow  must  also be unrestricted
in an arc of at least 270" around the inlet probe, and the predominant
direction for the season of greatest pollutant concentration potential
must be included in the 270° arc.   If the probe  is located on the side
of a building, 180° clearance is required.

3.3.5.3  Spacing from Roads - For those situations discussed above where
the emissions from a proposed source would impact  a street canyon/corridor
type area, the inlet probe must be located at least 10 meters from an
intersection and preferably at a midblock location.   The inlet probe must
also be placed 2-10 meters from the edge  of the  nearest traffic lane.
Additional information on CO probe siting may be found in reference 12.
                    •

3.3.6  Ozone (03)

3.3.6.1  Vertical and Horizontal  Probe Placement - The inlet probe for
ozone monitors should be as close as possible to the  breathing zone.  The
complicating factors discussed previously, however, require that the probe
be elevated.  The height of the inlet probe must be located 3 to 15 meters
above ground level.  The probe must also  be located more than 1 meter
vertically or horizontally away from any  supporting structure.

3.3.6.2  Spacing from Obstructions - The  probe must be located away from
obstacles and buildings such that the distance between the obstacles and
the inlet probe is at least twice the height  that  the obstacle protrudes
above the sampler.  The probe should also be  located  at least 20 meters
from trees.  Since the scavenging effect  of trees  is  greater for ozone
than for some of the other pollutants, strong consideration should be
used in locating the inlet probe to avoid this effect.  Airflow must be
unrestricted in an arc of at least 270° around the inlet probe, and the
predominant direction for the season of greatest pollutant concentration
potential  must be included in the 270° arc.   If the probe is located on
the side of a building, 180° clearance is required.

3.3.6.3  Spacing from Roads - It is important in the  probe siting process
to minimize destructive interferences from sources of nitric oxide (NO)
since NO readily reacts with ozone.   Regarding NO  from motor vehicles,
Table 2 provides the required minimum separation distances between road-
ways and ozone monitoring stations.   These distances  were based on recal-
culations using the methodology in reference  13 and validated using more
recent ambient data collected near a major roadway.   The minimum separa-
tion distance must also be maintained between an ozone station and other
similar volumes of automotive traffic, such as parking lots.   Additional
information on ozone probe siting criteria may be  found in reference 13.


                                    26

-------
       Table 2.   MINIMUM SEPARATION  DISTANCE  BETWEEN OZONE MONITORS
                    AND  ROADWAYS  (EDGE  OF NEAREST TRAFFIC LANE)

     Roadway Average Daily  Traffic,Minimum Separation Distance Between
           Vehicles Per Day	Roadways and Monitors, Meters
< 10,000
~ 15,000
20,000
40,000
70,000
>11 0,000
> 10*
"20
30
50
100
>250
^Distances should be interpolated  based on traffic  flow.


3.3.7  Nitrogen Dioxide (N02)

3.3.7.1  Vertical and Horizontal Probe Placement  -  As discussed  for
previous pollutants, the acceptable ranges for  a  monitor/probe inlet for
monitoring N02 emissions in  an  area principally influenced by an elevated
source is 3-15 meters.  For  areas  influenced  primarily by a ground level
source, the height should be as close  to  3 meters as possible.   Regarding
the distance of the probe from  the supporting structure, a vertical or
horizontal distance of 1  meter  must be maintained.

3.3.7.2  Spacing from Obstructions - Buildings, trees, and other obstacles
can serve as scavengers of N02-   Tn order to  avoid  this kind of  interfer-
ence, the station must be located  well away from  such obstacles  so that
the distance between obstacles  and the inlet  probe  is at least twice the
height that the obstacle protrudes above  the  probe.  Also, a probe inlet
along a vertical  wall  is undesirable because  air  moving along that wall
may be subject to possible removal mechanisms.  Similarly, the inlet
probe should also be at least 20 meters from  trees.  There must be unre-
stricted airflow in an arc of at least 270° around  the inlet probe, and
the predominant direction for the  season  of greatest pollutant concentra-
tion potential must be included in the 270° arc.  If the probe is located
on the side of the building, 180°  clearance is  required.  Additional
information on N0£ probe siting criteria  may  be found in reference 13.
3.3.8  Lead (Pb)

3.3.8.1  Vertical Placement - Breathing height  is  the most desirable
location for the vertical  placement  of  the  Pb monitor.   However, practical
factors previously mentioned require that the monitor be elevated.  In
elevating the sampler, consideration must be given to ground level emissions
(whether they be stationary or mobile sources)  with  steep vertical concen-
tration gradients.   Placing the shelter too high could result in measured
values significantly lower than the  level breathed by the general public.
Accordingly, the sampler for ground  level source monitoring must be located
2 to 7 meters above ground level.   In contrast, samplers to monitor for
elevated sources, as noted in previous  discussion, are allowed a wider
range of heights for locating the  sampler/inlet probe.   For Pb samplers,
the acceptable range for monitoring  emissions from elevated sources is
2-15 meters above ground level.


                                    27

-------
3.3.8.2  Spacing from Obstructions - A minimum of 2 meters  of separation
from walls, parapets, and penthouses is required for samplers located on
a roof or other structure.  No furnace or incineration  flues  should  be
nearby.  The height of the flues and the type, quality,  and quantity of
waste or fuel burned determine the separation distances  from  flues.  For
example, if the emissions from the chimney have a high  lead content  and
there is a high probability that the plume would impact on  the sampler
during most of the sampling period, then other buildings/locations in
the area that are free from the described sources should be chosen for
the monitoring site.  The sampler should be placed at least 20 meters
from trees, since trees absorb particles as well  as restrict  airflow.

     The sampler must be located away from obstacles such as  buildings,
so that the distance between obstacles and the sampler  is at  least twice
the height that the obstacle protrudes above the sampler.   There must
also be unrestricted airflow in an arc of at least 270°  around the
sampler, and the predominant direction for the season of greatest pollution
concentration potential must be included in the 270°  arc.

3.3.8.3  Spacing from Roads - For those situations discussed  in Section
3.3.8.1 where the emissions from a proposed source would impact close to
a major roadway (greater than approximately 30,000 ADT), the  air intake
for the monitor must be located within 15-30.meters from the  edge of the
nearest traffic lane.  Monitors located in this area would  thus measure
the combined impact from the proposed source and the roadway.   The sampler
air intake must be 2 to 7 meters above ground level.

3.3.8.4  Other Considerations - Stations should not be  located in an
unpaved area unless there is vegetative ground cover year round so that
the impact of reentrained or fugitive dusts will  be kept to a minimum.
Additional information on Pb siting criteria may be found in  reference 14.

3.3.9  Noncriteria Pollutants

3.3.9.1  Vertical Placement - Similar to the discussion  on  criteria
pollutants, the most desirable height for monitors/inlet probes for
noncriteria pollutants is near the breathing zone.   Again,  practical
factors require that the monitor/ inlet probe be elevated.  Furthermore,
consideration must be given to the type of source, i.e., elevated, ground
level, stationary, or mobile.  As the case may be, for  noncriteria parti-
culate pollutant monitors, the following monitor/inlet  probe  ranges  are
acceptable: for impact areas predominantly influenced by elevated sources,
2-15 meters;.for ground level sources 2 to 7 meters.  Regarding noncriteria
gaseous pollutants, acceptable heights are as follows:   areas  impacted
primarily by elevated sources, 3-15 meters; areas affected  principally by
ground level  sources, as close to 3 meters as possible.

3.3.9.2  Spacing from Obstructions - If the sampler/inlet probe is located
on a roof or other structure, then there must be  a minimum  of  2 meters
separation from walls, parapets, penthouses, etc.  No furnace  or inciner-
ation flues should be nearby.  This separation distance  from  flues is
dependent on the height of the flues, type of waste or  fuel burned, and
quality of the fuel.   For example, if the emissions from the  chimney
contain a high concentraton of the noncriteria pollutant that is being
measured and there is a high probability that the plume  would  impact the


                                    28

-------
sampler/inlet probe during most of the sampling  period,  then other buildings/
locations in the area that are free from  the  described sources should be
chosen for the monitoring site.  The sampler/inlet  probe should also be
placed at least 20 meters from trees.

     The sampler/inlet probe must be located  away from obstacles and
buildings such that the distance between  the  obstacles and  the sampler/
inlet probe is at least twice the height  that the obstacle  protrudes
above the sampler/inlet probe.  Airflow must  be  unrestricted in an arc
of at least 270° around the sampler/inlet probe, and  the predominant
direction for the season of greatest pollutant concentration potential
must be included in the 270° arc.  If the inlet  probe is located on the
side of a building, 180° clearance is  required.

3.3.9.3  Other Considerations - Stations  for  measuring particulate non-
criteria pollutants should not be located in  an  unpaved  area unless there
is vegetative ground cover year round so  that the impact of reentrained
or fugitive dusts will  be kept to a minimum.

3.4  Probe Material and Pollutant Sample  Residence  Time

     For reactive gases, special  probe material  must be  used.  Studies
[29-33] have been conducted to determine  the  suitability of materials
such as polypropylene,  polyethylene,  polyvinylchloride,  tygon, aluminum,
brass, stainless steel, copper, pyrex glass,  and teflon  for use as intake
sampling lines.  Of the above materials,  only pyrex glass and teflon have
been found to be acceptable for use as intake sampling lines for all the
reactive gaseous pollutants.   Furthermore, EPA [34] has  specified borosi-
1icate glass or FEP teflon as the only acceptable probe  materials for
delivering test atmospheres in the determination of reference or equiva-
lent methods.  Therefore, borosilicate glass, FEP teflon, or their
equivalent must be used for inlet probes.

     No matter how unreactive the sampling probe material is initially,
after a period of use,  reactive particulate matter  is deposited on the
probe walls.  Therefore, the time it takes the gas  to transfer from the
probe inlet to the sampling device is  also critical.  Ozone in the pre-
sence of NO will show significant losses  even in the most inert probe
material  when the residence time exceeds  20 seconds [35].   Other studies
[36-37] indicate that a 10-second or less residence time is easily achiev-
able.  Therefore, sampling probes for  reactive gas  monitors must have a
sampler residence time less than 20 seconds.

3.5  Summary of Probe Siting Requirements

     Table 6 presents a summary of the requirements for  probe siting criteria
with respect to distances and heights.  These criteria are  specified for
consistency between pollutants and to  allow the  use of a single manifold
for monitoring more than one pollutant at a site.
                                   . 29

-------
                                    TABLE  3.  SUMMARY OF PROBE SITING CRITERIA
                    Height Above
      Pollutant    Ground, Meters3
                 Distance  from  Supporting
                    Structure,  Meters

                 Vertical   • Horizontal
                 Other Spacing Criteria
         TSP
2 - 15
>2
       (old criteria
        for Section 3.3.1)
1,
2.
                                                                  3.

                                                                  4,

                                                                  5.
Should be >20 meters from trees.
Distance from sampler to obstacle,  such  as
buildings, must be at least twice  the
height the obstacle protrudes above the
sampler.
Must have unrestricted airflow 270° arc
around the sampler.
No furnace or incineration flues  should
be nearby.0
Must have minimum spacing from roads. This
varies with height of monitor (see  Figure  1)
CO
o
         TSP
2 - 7
>2
       (new criteria for impact  near
        roadway and/or ground level  sources)
1.
2.
                                                                  3,

                                                                  4.

                                                                  5.
Should be >20 meters from trees.
Distance from sampler to  obstacle,  such  as
buildings, must be at least twice the
height the obstacle protrudes  above the
sampler.
Must have unrestricted airflow 270° arc
around the sampler.
No furnace or incineration flues  should
be nearby.c
Must be 5-15 meters from  roads.
         TSP          2 - 15

       (new criteri a)
                                >2
            1.
            2.
                                                                  3.

                                                                  4.

                                                                  5.
    Should be >20  meters  from  trees.
    Distance from  sampler to obstacle, such
   •buildings, must  be  at least twice the
    height the obstacle protrudes  above  the
    sampler.
    Must have unrestricted airflow 270°  arc
    around the sampler.
    No furnace or  incineration flues should
    be nearby.c
    Must have minimum  spacing  from roads.
                                                                                        as

-------
                                     TABLE 3.  SUMMARY OF  PROBE  SITING CRITERIA

                                                    (continued)
Pollutant
  Height Above
Ground, Meters3
Distance from Supporting
    Structure, Meters

Vertical     Horizontal15
  Other Spacing Criteria
                   2  -  7
                                          >2
t
(impact near
 major roadway
 and/or ground
 level sources)
                           1.
                           2.
                                                                   3.

                                                                   4.
Should be >20 meters from trees.
Distance from sampler to obstacle, such
as buildings, must be at least twice
the height the obstacle protrudes above
the sampler.
Must have unrestricted airflow 270° arc
around the sampler.
No furnace or incineration flues  which
emit particulate matter should be
nearby.0
Must be 5-15 meters from roads.
                   2-15
                                          >2
                           1.
                           2.
                                                                  3.

                                                                  4.
Should be >20 meters from trees.
Distance from sampler to obstacle, such
as buildings, must be at least twice the
height the obstacle protrudes above the
sampler.
Must have unrestricted airflow 270° arc
around the sampler.
No furnace or incineration flues which
emit particulate matter should be
nearby.0

-------
                                    TABLE  3.  SUMMARY OF PROBE SITING CRITERIA

                                                  (continued)
                                       Distance from Supporting
                                         Structure, Meters
Height Above
Pollutant Ground, Meters3 Vertical Horizontal''
S02 3-15 >1 >1 1.
2.
Other Spacing Criteria
Should be >20 meters
Distance from inlet c
from trees .
>robe to obstacle,
such
                                                                      as buildings, must be at  least twice the
                                                                      height the obstacle  protrudes above the
                                                                      inlet probe.
                                                                  3.  Must have unrestricted  airflow 270° arc
                                                                      around the inlet  probe, or 180°  if probe  is
                                                                      on the side of  a  building.
                                                                  4.  No furnace or incineration  flues  should be
                                                                      nearby.0
CO
ro
          CO
     (street canyon)
3 + 1/2
              >1
1.

2.

3.
Must be >10 meters from intersection  and
should be at a midblock location.
Must be 2-10 meters from edge  of nearest
traffic lane.
Must have unrestricted airflow 180° around
the inlet probe.
          CO
     (non-street
     canyon/corridor)
 3-15
>1
    Must have unrestricted airflow 270° around
    the inlet probe,  or 180°  if  probe  is on  the
    side of a building.

-------
                                         TABLE 3.   SUMMARY OF  PROBE SITING CRITERIA

                                                        (continued)
                     Height Above
    Pollutant      Ground, Meters8
                                            Distance from  Supporting
                                               Structure,  Meters
                                    Vertical
                Horizontal^
            Other Spacing Criteria
                      3  - 15
                                 >1
             >1
1.  Should be >20 meters from trees.
2.  Distance from inlet probe to obstacle,  such
    as buildings, must be at least  twice  the
    height the obstacle protrudes above the
    inlet probe.
3.  Must have unrestricted airflow 270° arc
    around the inlet probe, or 180° if  probe
    is on the side of a building.
4.  Spacing from  roads varies with  traffic
    (see Table 2).
OJ
OJ
N02
                      3-15
>1
1.  Should be >20 meters from trees.
2.  Distance from inlet probe to obstacle,  such
    as buildings, must be at least  twice  the
    height the obstacle protrudes above the
    inlet probe.
3.  Must have unrestricted airflow 270° arc
    around the inlet probe, or 180° if  probe
    is on the side of a building.
        Pb
    (impact near
     major roadway
     and/or ground
     level sources)
              2  -  7
             >2
1.
2.
                                                          3.

                                                          4.

                                                          5.
Should be >20 meters from trees.
Distance from sampler to  obstacle,  such  as
buildings, must be at least twice  the height
obstacle protrudes above  the sampler.
Must have unrestricted airflow 270°  arc
around the sampler.
No furnace or incineration flues which emit
lead should be nearby.0
Must be 15-30 meters from major roadways.

-------
                                     TABLE 3.  SUMMARY OF PROBE SITING CRITERIA
                                                    (continued)
Pollutant
  Height Above
Ground, Meters3
                                        Distance from Supporting
                                           Structure, Meters
Vertical
Horizontal0
  Other Spacing Criteria
   Pb
    2-15
                  >2
              1.
              2.
                                                                    3.

                                                                    4.
Should be >20 meters from trees.
Distance from sampler to obstacle,
such as buildings, must be at least
twice the height the obstacle protrudes
above the sampler.
Must have unrestricted airflow 270° arc
around the sampler.
No furnace or incineration flues  which
emit lead should be nearby.0
 Particulate
 Noncriteria
 Pollutants
    2 - 7 for
  ground 1evel
  sources;
    2 - 15 for
  elevated sources
                  >2
              1.   Should be  >20  meters  from  trees.
              2.   Distance from  sampler to obstacle,  such
                  as buildings,  must  be at least  twice
                  the height the obstacle protrudes
                  above the  sampler.
              3.   Must have  unrestricted airflow  270° arc
                  around the sampler.
              4.   No furnace or  incineration  flues which
                  emit the noncriteria  pollutant  should
                  be nearby.0

-------
                                         TABLE 3.  SUMMARY OF PROBE SITING  CRITERIA

                                                        (continued)
Pollutant
                     Height  Above
                    Ground,  Meters3
Distance from  Supporting
    Structure,  Meters

 Vertical     Horizontal5
                                                                         Other Spacing Criteria
OJ
en
Gaseous
Noncriteria
Pollutants
                       3-15
                                                                   1.   Should  be  >20  meters  from  trees.
                                                                   2.   Distance from  inlet probe  to obstacle,
                                                                       such  as buildings, must  be at  least
                                                                       twice the  height obstacle  protrudes
                                                                       above the  inlet probe.
                                                                   3.   Must  have  unrestricted airflow 270° arc
                                                                       around  the inlet probe,  or 180°  if the
                                                                       probe is on the side  of  a  building.
                                                                   4.   No  furnace or  incineration flues which
                                                                       emit  the noncriteria  pollutant should
                                                                       be  nearby.5
     aFor ground level  sources, monitors/inlet probes should be placed as close to the  breathing  zone  as  possible.
           probe is located on  rooftop, this separation distance is in reference  to walls,  parapets,  or penthouses
      located on the roof.

     C0i stance is dependent on  height of furnace or incineration flue, type of fuel  or waste  burned,  and
      quality of fuel.  This is to avoid undue influences from minor pollutant sources.

-------
                   4.  QUALITY ASSURANCE FOR AIR  QUALITY  DATA
     On May 10, 1979, EPA promulgated quality assurance  requirements  for
PSD monitoring for $03, NOJ?, 03, CO, and TSP.  These quality  assurance
requirements are Appendix B of 40 CFR 58 (reference  8).   Section 4.1
describes minimum quality assurance requirements (promulgated and  planned)
for PSD monitoring for all criteria air pollutants  (S02,  N02, 03,  CO,
TSP, Pb and PM^Q).  Monitoring organizations  are  required  to meet
quality assurance requirements of Appendix B  at the  time the station is
put into operation.

     Currently, quality assurance for PSD monitoring for noncriteria air
pollutants are EPA recommendations only.   EPA promulgated  requirements are
not available for noncriteria air pollutants.  Section 4.2 describes
minimum quality assurance recommendations for noncriteria  air  pollutants.


4.1   Quality Assurance for Criteria Air Pollutants

4.1.1  General Information

     The following specifies the minimum quality  assurance requirements of
an organization operating a network of PSD stations.  These requirements
are regarded as the minimum necessary for the control and  assessment of the
quality of the PSD ambient air monitoring data submitted to EPA. Organiza-
tions are encouraged to develop and implement quality assurance programs
more extensive than the minimum required or to continue  such programs
where they already exist.

     Quality assurance consists of two distinct and  equally important
functions.  One function is the assessment of the  quality  of the monitoring
data by estimating their precision and accuracy.   The other function is the
control, and improvement, of the quality of the monitoring data by implemen-
tation of quality control policies, procedures, and  corrective actions.
These two functions form a control  loop;   when the assessment  function
indicates that the data quality is inadequate, the control effort must
be increased until the data quality is acceptable.

     In order to provide uniformity in the assessment and  reporting of data
quality, the assessment procedures are specified  explicitly in Sections
4.1.3, 4.1.4, 4.1.5 and 4.1.6.

     In contrast, the control and corrective  action  function encompasses a
variety of policies, procedures, specifications,  standards, and corrective
measures which have varying effects on the resulting data,  quality.  The
selection and degree of specific control  measures  and corrective actions
used depend on a number of factors such as the monitoring  methods and
equipment used, field and laboratory conditions,  the objectives of the
monitoring, the level of data quality needed, the expertise of personnel,
                                    36

-------
the cost of control  procedures,  pollutant concentration  levels, etc.
Accordingly, quality control  requirements are  specified  in general
terms, in Section 4.1.2 to allow each organization  to  develop  a quality
control  system which is most  effective for its own  circumstances.

     For purposes here, "organization" is defined as a source  owner/operator,
a government agency, or their contractor  which operates  an ambient air
pollution monitoring network  for PSD purposes.

4.1.2  Quality Control  Requirements

4.1.2.1   Organizational Requirements - Each organization must develop
and implement a quality control  program consisting  of  policies, procedures,
specifications, standards and documentation necessary  to:

     (a)  meet the monitoring objectives  and quality assurance requirements
of the permit granting  authority

     (b)  minimize loss of air quality data due to  malfunctions or out-
of-control  conditions,

     The quality control program must be  described  in  detail,  suitably
documented, and approved by the  permit granting authority.

4.1.2.2  Primary Guidance - Primary  guidance for developing  the quality
control  program is contained  in  references 38  and 39,  which  also contain
many suggested procedures, checks, and control  specifications. Section
2.0.9 of reference 39 describes  the  specific guidance  for the  development
of a quality control program  for PSD automated analyzers and manual
methods.  Many specific quality  control checks  and  specifications for
manual methods are included in the respective  reference  methods described
in 40 CFR 50, or in  the respective equivalent  method descriptions available
from EPA (see Section 2.6).  Similarly, quality control  procedures related
to specifically designated reference and  equivalent analyzers  are contained
in their respective  operation and instruction  manuals.   This guidance,
and any other pertinent information  from  appropriate sources,  should be
used by organizations in developing  their quality control programs.
     As a minimum each  quality control  program must have operational
procedures for each  of  the following activities:

     (a)  selection  of  methods,  analyzers, or  samplers,
     (b)  installation  of equipment,
     (c)  calibration,
     (d)  zero and span checks and adjustments of automated  analyzers,
     (e)  control checks and  their frequency,
     (f)  control limits for  zero, span and other control checks, and
          respective corrective  actions when such limits are surpassed,
     (g)  calibration and zero/span  checks for multiple  range  analyzers
     (h)  preventive and remedial maintenance
     (i)  recording  and validating data
     (j)  documentation of quality control  information.
                                    37

-------
     As previously mentioned, specific guidance  for  each  activity listed
above that must be a part of an organization's quality control program
is described in Section 2.0.9 of reference  39.

4.1.2.3  Pollutant Standards - Gaseous standards (permeation tubes,
permeation devices or cylinders of compressed  gas) used to obtain test
concentrations for CO,  S02, and N02 must be working  standards certified
by comparison to a National Bureau of  Standards  (NBS) gaseous Standard
Reference Material (SRM).  A traceability protocol for certifying a
working standard by direct comparison  to an NBS  SRM  is given in reference
40.  Direct use of an NBS SRM as a working  standard  is not prohibited
but is discouraged because of the limited supply and expense of NBS
SRM's.  When available, gas manufacturers'  cylinder  gases Certified
Reference Materials "CRM" may be substituted for NBS SRM cylinder gases
in establishing traceability.

     Test concentrations for ozone must be  obtained  in accordance with
the UV photometric calibration procedure specified in Appendix D of
40 CFR 50, or by means  of an ozone transfer standard which has been
certified.  Consult reference 41 for guidance on ozone transfer standards.

     Flow measurements  must be made by a flow measuring instrument which
is traceable to an authoritative volume or  other standard.

4.1 .2.4  Performance and System Audit  Programs - The organization operating
a PSD monitoring network must participate in EPA's national performance
audit program.  The permit granting authority, or EPA, may conduct system
audits of the ambient air monitoring programs of organizations operating
PSD networks.  See Section 1.4.16 of reference 38 and Sections 2.0.11 and
2.0.12 of reference 39  for additional  information about these programs.
Organizations should contact either the appropriate  EPA Regional Quality
Control Coordinator or  the Quality Assurance Division, EMSL/RTP, at the
address given in reference 40 for instructions for participation.

4.1 .3  Data Quality Assessment Requirements

4.1.3.1  Precision of Automated Methods - A one-point precision check must
be carried out at least once every two weeks on  each automated analyzer
used to measure SOg, N02, 03, and CO.   The  precision check is made by
challenging the analyzer with a precision check  gas  of known concentration
between 0.008 and 0.10  ppm for S02,  N02, and 03  analyzers, and between 8
and 10 ppm for CO analyzers.   The standards from which precision check test
concentrations are obtained must meet  the specifications of section 4.1.2.3.
Except for certain CO analyzers described below, analyzers must operate in
their normal sampling mode during the  precision  check, and the test atmosphere
must pass through all filters, scrubbers, conditioners, and other components
used during normal ambient sampling and as  much  of the ambient air inlet
system as is practicable.  If permitted by  the associated operation or
instruction manual, a CO analyzer may  be temporarily modified during the
precision check to reduce vent or purge flows, or the test atmosphere
may enter the analyzer  at a point other than the normal sample inlet,
provided that the analyzer's response  is not likely  to be altered by
these deviations from the normal  operational mode.
                                   38

-------
      If a precision check is made in conjunction with zero/span adjustment,
 it must be made prior to such zero and span adjustments.   The  difference
 between the actual concentration of the precision check gas and the
.concentration indicated by the analyzer is used to assess the  precision
 of the monitoring data as described in Section 4.1.4.1.  Report data
 only  from automated analyzers that are approved for use in the PSD network.

 4.1 .3.2  Accuracy of Automated Methods - Each sampling quarter audit each
 analyzer that monitors for S02, N02, 03, or CO at least once.   The audit
 is made by challenging the analyzer with at least one audit gas of known
 concentration from each of the following ranges which fall within the
 measurement range of the analyzer being audited:

                                      Concentration Range, ppm
Audit Point
1
2
3
4
S02, N02, 03
0.03 to 0.08
0.15 to 0.20
0.40 to 0.45
0.80 to 0.90
CO
3 to 8
15 to 20
40 to 45
80 to 90
 The  standards from which audit gas test concentrations  are  obtained must
 meet the specifications of Section 4.1.2.3.   Working and transfer standards
 and  equipment used for auditing must be different from  the  standards and
 equipment used for calibration and spanning.  The auditing  standards and
 calibration standards may be referenced to the same MBS SRM or  primary UV
 photometer.  The auditor must not be the operator/analyst who conducts the
 routine monitoring, calibration, and analysis.

      The audit shall be carried out by allowing the analyzer to analyze an
 audit test atmosphere in the same manner as described for precision checks
 in Section 4.1.3.1.  The exception given in Section 4.1.3.1  for certain CO
 analyzers does not apply for audits.

      The difference between the actual concentration of the audit test gas
 and  the concentration indicated by the analyzer is used to  assess the
 accuracy of the monitoring data as described in Section 4.1.4.2.   Report
 data only from automated analyzers that are approved for use in the PSD
 network.

 4.1.3.3  Precision of Manual Methods - (a) JSP and PMip Methods.   For a given
 organization1 s monitoring network, one sampling site must have  collocated
 samplers.  A site with the highest expected 24-hour pollutant concentration
 must be selected.  The two samplers must be within 4 meters of  each other
 but  at least 2 meters apart to preclude airflow interference.   Calibration,
 sampling, and analysis must be the same for both collocated samplers as well
 as for all other samplers in the network.  The collocated samplers must be
 operated as a minimum every third day when continuous sampling  is used.
 When a less frequent sample schedule is used, the collocated samplers must
                                    39

-------
be operated at least once each week.  For each  pair  of collocated  samplers,
designate one sampler as the sampler which  will  be used to report air quality
for the site and designate the other as  the duplicate sampler.  The differences
in measured concentration (pg/ir?)  between the two collocated  samplers are
used to calculate precision as described in Section  4.1.5.1.

     (b)  Pb Methods.  The operation of  collocated samplers at one sampling
site must be used to assess the precision of the reference or an equivalent
lead method.  The procedure to be  followed for  lead  methods is the same as
described in 4.1.3.3(a) for the TSP and  PM   methods.
4.1.3.4  Accuracy of Manual  Methods -  (a)  TSP  and PMjp Methods.  Each sampling
quarter audit the flow rate  of each sampler  at least once.
Audit the flow at the normal  flow rate,  using  a certified  flow transfer
standard (see reference 39).   The flow transfer standard used for the
audit must not be the same one used to calibrate the flow  of the sampler
being audited, although both  transfer  standards may be referenced to the
same primary flow or volume standard.  The difference between the audit
flow measurement and the flow indicated  by the sampler's flow indicator
is used to calculate accuracy, as described  in Section 4.1.5.2

     Great care must be used  in auditing high-volume samplers having
flow regulators because the  introduction of  resistance plates in the
audit device can cause abnormal  flow patterns  at the point of flow
sensing.  For this reason, the orifice of  the  flow audit device should
be used with a normal  glass  fiber filter in  place and without resistance
plates in auditing flow regulated high- volume  samplers, or other steps
should be taken to assure that flow patterns are not perturbed at the
point of flow sensing.

     (b)  Pb Methods.   For the reference method (Appendix  G of 40 CFR 50)
each sampling quarter  audit  the flow rate  of each high-volume lead sampler
at least once.  Audit the flow rate at one flow rate using a reference flow
device described in Section  2.2.8 of reference 39, or a similar flow
transfer standard.  The device used for  auditing must be different from
the one used to calibrate the flow of  the  high-volume sampler being audited.
The auditing device and the  calibration  device may both be referenced to
the same primary flow  standard.   With  the  audit device in  place, operate
the high-volume sampler at its normal  flow rate. The difference in flow
rate (in m^/min) between the  audit flow  measurement and the flow indicated
by the sampler's normal flow indicator are used to calculate accuracy as
described in Section 4.1.5.3.

     Great care must be used  in auditing high-volume sampler having flow
regulators because the introduction of resistance plates in the audit
device can cause abnormal  flow patterns  at the point of flow sensing.
For this reason, the orifice  of the flow audit device should be used
with a normal glass fiber filter in place  without resistance plates to
audit flow regulated high-volume samplers, or  other steps should be
taken to assure that flow patterns are not perturbed at the point of
flow sensing.

     Each sampling quarter,  audit the  lead analysis using glass fiber
filter strips containing a known quantity  of lead.   Audit samples are
prepared by depositing a lead solution on  1.9  cm by 20.3 cm (3/4 inch
by 8 inch) unexposed glass fiber filter  strips  and allowing to dry


                                    40

-------
thoroughly.  The audit samples must be  prepared  using  reagents different
from those used to calibrate the  lead analytical equipment being audited.
Prepare audit samples in the following  concentration ranges:

                                                   Equivalent Ambient
                   Cone, yg Pb/strip               Cone. yg Pb/m3*

                      100 to 300                     0.5 to 1.5

                      600 to 1000                   3.0 to 5.0
*Equivalent ambient lead concentration  in  yg/rn   is based on sampling
at 1.7 mVmin for 24 hours on 20.3 cm x 25.4  (8  inch  x 10  inch)  glass
fiber filter.

     Audit samples must be extracted using the same extraction procedure
used for exposed filters.

     Analyze at least one audit sample  in  each of the two  ranges each
day that samples are analyzed.   The difference between the audit concentration
(in yg Pb/strip) and the analyst's measured concentration  (in yg Pb/strip)
are used to calculate analysis  accuracy as described  in Section  4.1.5.4.

     The accuracy of an equivalent method  is  assessed in the same manner
as the reference method.   The flow auditing device and lead analysis
audit samples must be compatible with the  specific requirements  of the
equivalent method.

4.1 .4  Calculations for Automated Methods

4.1.4.1   Single Analyzer Precision - Each  organization, at the end of each
sampling quarter, shall calculate and report  a precision probability interval
for each analyzer.  Directions  for calculations  are given below and directions
for reporting are given in Section 4.1.6.   If monitoring data are  invalidated
during the period represented by a given precision check, the results of
that precision check shall be excluded  from the  calculations.  Calculate
the percentage difference (d-j)  for each precision check using equation 1.


                              Yi  - XT   '                            (1 )
                        d,- =  - x 100
                                XT


where:  Yj = analyzer's indicated concentration  from  the i-th precision
             check,


       Xj = known concentration of the  test gas  used  for the i-th precision
            check.
                                    41

-------
For each instrument, calculate the quarterly average (3j),  equation  2, and
the standard deviation (Sj), equation 3.

                        1   n                                         (2)

                  dj  =   rf ,  ,  di
                                 9
                                 <
                                                                     (3)
Where n is the number of precision checks on  the  instrument made during
the sampling quarter.  For example, n should  be 6 or  7  if  span checks are
made bi-weekly during a quarter.

     Calculate the 95 percent probability limits  for  precision using
equations 4 and 5.

     Upper 95 Percent Probability Limit = dj  +  1.96 Sj               (4)

     Lower 95 Percent Probability Limit = dj  - 1.96 Sj               (5)

4.1.4.2  Single Analyzer Accuracy - Each organization,  at  the end of each
sampling quarter, shall calculate and report  the  percentage difference for
each audit concentration for each analyzer audited during  the quarter.
Directions for calculations are given below (directions for reporting
are given in Section 4.1.6).

     Calculate and report the percentage difference (d^) for each audit
concentration using equation 1  where Y-j is the analyzer's  indicated
concentration from the i-th audit check and X?- is the known concentration
of the audit gas used for the i-th audit check.

4.1 .5  Calculations for Manual  Methods

4.1.5.1  Single Instrument Precision for JSP, Pb, and PMjp.  Estimates of
precision for ambient air quality particulate measurements are calculated
from results obtained from collocated samplers as described in section
4.1.2.3.  At the end of each sampling quarter, calculate and report a
precision probability interval, using weekly  results  from  the collocated
samplers.  Directions for calculations are given  below, and directions
for reporting are given in Section 4.1.6.

     For the paired measurements  obtained as  described  in  sections 4.1.2.3(a)
and 4.1.2.3(b), select all pairs  in which both measurements are above 20
yg/m3 for TSP, 0.25 yg/m3 for Pb, or 20 yg/m3 for PM1Q.  For each selected
pair, calculate the percent difference (d-j) using equation 1, where Y^  is the
concentration of pollutant measured by the duplicate  sampler, and X-j is
the concentration measured by the sampler reporting air quality for the
site.  Calculate the quarterly average percent difference  (dj), equation
2, standard deviation (Sj), equation 3, and upper and lower 95 percent
probability 1 imts for precision (equations 6  and  7).


                                    42

-------
     Upper 95 Percent Probability Limit =  dj  +  1.96 Sj/  fT~           (6)

     Lower 95 Percent Probability Limit =  dj  -  1.96 Sj/  i~T~           (7)

4.1.5.2  Single Instrument Accuracy  for JSP  and PMjp  - Each  organization,
at the end of each sampling quarter,  shall calculate  and report the
percentage difference for each high-volume or PM^g sampler audited
during the quarter.   Directions for calculation are given below and
directions for reporting are given in Section 4.1.6.

     For the flow rate audit described  in  Section 4.1.3.4, let Xi
represent the known  flow rate and Y-j  represent  the indicated flow rate.
Calculate the percentage difference  (d-j) using  equation  1.

4.1.5.3  Single Instrument Sampling Accuracy for Pb - Each organization,
at the end of each sampling quarter,  shall calculate  and report the
percentage difference for each high-volume lead sampler audited during
the quarter.  Directions for calculation are given in Section 4.1.5.2 and
directions for reporting are given in Section 4.1.6.

4.1.5.4  Single-Analysis-Day Accuracy for  Pb -  Each organization, at the
end of each sampling quarter, shall calculate and report the percentage
difference for each  Pb analysis audit during the quarter.  Directions
for calculations are given below and  directions for reporting are given
in Section 4.1.6.

     For each analysis audit for Pb  described in Section 4.1.3.4(b), let
X-j represent the known value of the audit  sample and  Yj the  indicated
value of Pb.  Calculate the percentage  difference (d-j) for each audit at
each concentration level  using equation 1.

4.1.6  Organization  Reporting Requirements

       At the end of each sampling quarter,  the organization must report
the following data assessment information:   (a) for automated analyzers -
precision probability limits from Section  4.1.4.1 and percentage differences
from Section 4.1.4.2, and (b) for manual methods - precision probability
limits from Section  4.1.5.1 and percentage differences from  Sections
4.1.5.2, 4.1.5.3 and 4.1.5.4.  The precision and accuracy information
for the entire sampling quarter must  be submitted with the air monitoring
data.  All data used to calculate reported estimates  of precision and
accuracy including span checks, collocated sampler and audit results
must be made available to the permit  granting authority upon request.

4.2  Quality Assurance for Noncriteria  Air Pollutants

     At the present  time, there are  no  EPA regulations on quality assurance
for PSD monitoring of noncriteria air pollutants.  The following are EPA
recommendations for  a minimum quality assurance program  for  noncriteria
pollutants.

4.2.1  Selection of  Method

       Selection of  the measurement method for  noncriteria air pollutants
is extremely important.   A list of acceptable measurement methods for
noncriteria air pollutants is available and  may be obtained  by writing:


                                   43

-------
U.S. Environmental  Protection Agency,  Environmental  Monitoring  Systems
Laboratory, Quality Assurance Division (MD-77),  Research  Triangle  Park,
North Carolina  27711. This list of acceptable methods  will  be  revised
at least annually and be available from the  above  address.   Measurement
methods considered candidates for the  noncriteria  pollutant  list should
be brought to the attention of EPA at  the  address  given above.

4.2.2  Calibration

       Calibration procedures described in the acceptable methods  should
be followed and a schedule for calibrations  should be established.   In
addition, flow measurement devices used to measure sampling  rate should
be calibrated and a schedule established for recalibration.   Calibration
procedures for several flow measurement devices  (rotameter,  critical
orifice, mass flow meter, and wet test meter) are  described  in  Section
2.1.2 of reference 39.  All calibration procedures should be written and
maintained up-to-date by a document control  system.  A  description of one
document control system that has been  found  to be  effective  is  discussed
in Section 1.4.1 of reference 38.

4.2.3  Data Validation

       Measurement data of poor quality may  be worse than no data  at all.
Therefore, the monitoring organization should establish data validation
procedures and implement these procedures  to invalidate data of question-
able quality.  Examples of data validation procedures for criteria pollu-
tants described in Section 2.0.9 of reference 39 may be useful  as  a guide
in establishing data validation procedures for noncriteria pollutants.

4.2.4  Standard and Split Samples
       Where possible, standard samples containing the  pollutant of
interest should be analyzed periodically during  the  analysis of collected
samples.  This practice is useful  in helping to  determine if the analytical
system is in control.  Splitting samples with another laboratory is quite
useful  in determining if there are unidentified  biases  in the analytical
system.
                                    44

-------
                         5.   METEOROLOGICAL  MONITORING
5.1  Data Required
     The preconstruction review of proposed  major  emitting  facilities
will  require the use of meteorological  data.   It is  essential that
such data be representative of atmospheric dispersion  conditions at
the source and at locations where  the  source may have  a significant
impact on air quality.  The representativeness  of  the  data  is dependent
upon (a) the proximity of the meteorological monitoring site to the
area under consideration, (b) the  complexity of the  topography of
the area, (c) the exposure of the  meteorological sensors, and (d) the
period of time during which the data are  collected.  More guidance
for determining representativeness is  presented in reference 42.

     A data base representative of the site  should consist  of at
least the following data:

     a.  hourly average wind speed and direction

     b.  hourly average atmospheric stability based  on Pasquill stability
         category or wind fluctuations (aQ), or vertical temperature
         gradient combined with wind speed

     c.  hourly surface temperature at standard height for  climatological
         comparisons and plume rise calculations

     d.  hourly precipitation amounts  for climatological comparisons.

     In addition, hourly average mixing heights may  be necessary for the
air quality impact analysis.  In most  cases, this may  be limited to an
extrapolation of twice-daily radiosonde measurements routinely collected
by the National Weather Service (NWS). Sections 5.2 and 6.1 contain
specific information on instrument exposure  and specifications.

     Requirements for additional instrumentation and data will depend
upon the availability of information needed  to  assess  the effects of
pollutant emissions on ambient air quality,  soils, vegetation, and
visibility in the vicinity of the  proposed source.   The type, quantity,
and format of the required meteorological  data  will  also be influenced
by the input requirements of the dispersion  modeling techniques used in
the air quality analysis.  Any application of dispersion modeling must
be consistent with the EPA "Guideline  on  Air Quality Models" [15].  The
guideline makes specific recommendations  concerning  air quality models
and data bases.  It also specifies those  situations  for which models,
data, and techniques other than those  recommended  therein, may be applied.

     Site-specific data are always preferable to data  collected off-site.
The availability of site-specific  meteorological data  permits relatively
detailed meteorological analyses and subsequent improvement of dispersion
model estimates.  An important source  of  background  information pertaining
to on-site meteorological  instrumentation is contained in an EPA workshop
report [43].  Off-site meteorological  data may  be  used in lieu of site-
specific data only if it is agreed by  source owner and permit granting
                                    45

-------
authority that the off-site data are  reasonably  representative of atmospheric
conditions in the area under consideration.   The off-site meteorological
data can sometimes be derived from routine measurements by  NWS stations.
The data are available as  individual  observations and in summarized form
from the National Climatic Data Center,  Federal  Building, Asheville, NC
28801.   On the other hand, if the nearest  source of off-site data is con-
siderably removed from the area under consideration, and especially if
there are significant terrain features,  urban areas, or large bodies of
water nearby, it may be necessary that the required meteorological data
be site-specific.

     In some cases, it will be necessary that data be collected at more
than one site in order to  provide a reasonable representation of atmospheric
conditions over the entire area of concern.  Atmospheric conditions may
vary considerably over the area.   In  some cases, (e.g., complex terrain)
it will not be feasible to adequately monitor the entire meteorological
field of concern.  Then the only recourse  is to  site the stations in
areas where characteristic and significant airflow patterns are likely to
be encountered.  In any event, one of the meteorological stations should
be located so that it represents atmospheric  conditions in  the immediate
vicinity of the source.

     Although at least 1 year of meteorological  data should be available,
a shorter period of record that conforms to the  air quality monitoring
period of record discussed in Section 2.5  is  acceptable when approved
by the permit granting authority.   If more than  1 year of data is avail-
able, it is recommended that such data be  included in the analysis.  Such
a multiyear data base allows for more comprehensive consideration of
variations in meteorological conditions  that  occur from year to year.  .A
5-year period of record will usually  yield an adequate meteorological
data base for considering  such year-to-year variations.

     In all  cases, the meteorological  data used  must be of at least
the quality of data collected by the  National Weather Service.  Desired
features of instrumentation for collecting meteorological data are
discussed in Section 6.1.

5.2  Exposure of Meteorological Instruments

     Measurements of most  meteorological parameters are affected by the
exposure of the sensor. Jo obtain comparable observations at different
sites, the exposures must  be similar.  Also, the exposure should be such
that the measured parameters provide  a good representation of pollutant
transport and dispersion within the area that the monitoring site is
supposed to represent.  For example,  if  wind  flow data over a fairly
broad area are desired, the wind sensors should  be away from the immediate
influence of trees, buildings, steep  slopes, ridges, cliffs, or hollows.

     The standard exposure of wind instruments over level open terrain
is 10 meters above the ground.  Open  terrain  is  defined as an area where
the distance between the anemometer and  any obstruction to  the wind flow
is at least five times the height of  the obstruction.  Where a standard
exposure is unobtainable at this height, the  anemometer should be installed
at such a height that its  indications are  reasonably unaffected by local
obstructions and represent as closely as possible what the  wind at 10
                                    46

-------
on assessing adverse aerodynamic effects  due  to  local obstructions is
contained in reference 44.   In  locating wind  sensors in rough terrain or
valley situations, it will  be necessary to  determine if local effects
such as channeling, slope and valley  winds, etc., are important, or
whether the flow outside those zones  of influence is to be measured.  If
the analysis concerns emissions from  a tall stack, it may be desirable
to avoid the local influences.   On  the other  hand, if pollution from
low-level sources is the main concern, the  local influences may be
important.

     If the source emission point is  substantially above the standard
10-meter level  for wind measurements, additional wind measurements at
the height of the emission point and  at plume height are desirable.
Such measurements are used to determine the wind regime in which the
effluent plume is transported away  from the source.  (The wind speed and
direction 50 to 100 meters or more  above  the  surface are often considerably
different than at the 10-meter level.)  An  instrumented tower is the most
common means of obtaining meteorological  measurements at several elevations
in the lower part of the atmospheric  boundary layer.  For wind instruments
mounted on the side of a tower, precautions must be taken to ensure that
the wind measurements are not unduly  influenced  by the tower.  Turbulence
in the immediate wake of a tower (even a  latticetype tower) can be severe.
Thus, depending on the supporting structure,  wind measuring equipment
should be mounted (e.g., on booms)  at least two  structure widths away
from the structure, and two systems mounted on opposite sides of the
structure will  sometimes be necessary.  A wind instrument mounted on top
of a tower should be mounted at least one tower  width above the top.  If
there is no alternative to mounting instruments  on a stack, the increased
turbulence problem [45], must be explicitly resolved to the satisfaction
of the permit granting authority.

     Atmospheric stability is another key factor in pollutant dispersion
downwind of a source.  The stability  category is a function of static
stability (related to temperature change  with height), convective turbulence
(caused by heating of the air at ground level), and mechanical  turbulence
(a function of wind speed and surface roughness).  A procedure for estima-
ting stability category is given by Turner  [46] which requires information
on solar elevation angle, cloud cover, ceiling height, and wind speed.
The hourly observations at NWS stations include cloud cover, ceiling
height, and wind speed.  Alternative  procedures  for estimating stability
category may be applied if representative data are available.  For example,
stability category estimates may be based upon horizontal wind direction
fluctuations [47], or vertical  gradients  of temperature and wind speed
[48].  To obtain a representative reading of  the air temperature, the
temperature sensor should be protected from thermal radiation from the
sun, sky, earth, and any surrounding  objects, and must be adequately ven-
tilated.  Aspirated radiation shields are designed to provide such protec-
tion.  (Note that ambient temperature data  are also commonly required
for plume rise estimates used in dispersion model calculations.)

     Mixing height is another parameter that  can be important in some
cases.  Mixing height is the distance above the ground to which relatively
free vertical mixing occurs in the  atmosphere. For estimating long-term
average concentrations, it is adequate to use a  representative annual
                                    47

-------
average mixing height [49].   However,  in many cases,  and  especially  for
estimates of short-term concentrations,  twice-daily or  hourly mixing
height data are necessary.   Such data  can sometimes be  derived  [49]  from
representative surface temperatures  and  twice-daily upper air soundings
collected by selected NWS stations.

     Precipitation collectors must be  located so  that obstructions do
not prevent the precipitation from falling  into the collector opening or
force precipitation into the opening.  Several collectors may be  required
for adequate spatial  resolution in complex  topographic  regimes.

     Final rule making entitled "Visibility Protection  for  Federal Class
I Areas," was published in  the Federal Register on December 2,  1980.  The
regulations are applicable  to 36 States  1 isted in the action.   Although
these States are not  required to establish  visibility monitoring  networks,
they should consult with the Federal Land Managers to determine monitoring
needs.   Paragraph 51.305 states that the SIP strategies "must take into
account current and anticipated visibility  monitoring research, the avail-
ability of appropriate monitoring techniques and  such guidance  as is pro-
vided by the Agency."  Visibility definitions, monitoring methods, modeling
considerations and impact assessment approaches are among the subjects of
three EPA reports: (1) "Protecting Visibility: An EPA  Report to  Congress"
[50], (2) "Interim Guidance  for Visibility  Monitoring"  [51], and  (3)
"Workbook for Estimating Visibil ity Impairment" [52].   Also, since publi-
cation of the final rule, the National Park  Service has established a
visibil ity monitoring system.  The States or permit granting authority
should consider these resources when handling visibility  new source
review questions.

     Additional information  and guidance on siting and  exposure of
meteorological instruments  is contained  in  reference  53.
                                    48

-------
                      6.  METEOROLOGICAL  INSTRUMENTATION
6.1  Specifications
     Meteorological  instrumentation used for PSD monitoring must yield
reasonably accurate  and precise data.   Accuracies  and  allowable errors
are expressed in this section as absolute values for digital  systems;
errors in analog systems may be 50 percent greater.  For  example, an
allowable error expressed as 5 percent means the recorded value should
be within +5 percent of the true value for digital  systems, and +7.5
percent for analog systems.  Records should be  dated,  and should be
accurate to within 10 minutes.   Wind speed and  direction  (or  vector
components) should be recorded continuously on  strip recorders at
intervals not to exceed 60 seconds for a given  variable;  digital
recorders may be used as backup.  These specifications apply  to the
meteorological  instruments used to gather the site specific data that
will accompany a PSD permit application.  When  the use of existing
representative meteorological  data is  approved  by  the  permit  granting
authority, the instrumentation should meet, as  a minimum,  NWS standards
[54-55].

6.1.1   Wind Systems  (horizontal wind)

       Wind direction and wind speed systems should exhibit a starting
threshold of less than 0.5 meter per second (m/s)  wind speed  (at 10
degrees deflection for direction vanes).   Wind  speed systems  should be
accurate above the starting threshold to within 0.25 m/s  at speeds equal
to or less than 5 m/s.  At higher speeds, the error should not exceed 5
percent of the observed speed (maximum error not to exceed 2.5 m/s).  The
damping ratio of the wind vane should  be between 0.4 and  0.65 and the
distance constant should not exceed 5  m.  Wind  direction  system errors
should not exceed 5  degrees, including sensor orientation  errors.  Wind
vane orientation procedures should be  documented.

6.1.2   Wind Systems  (vertical  wind)

       In complex terrain, downwash of plumes due  to significant terrain
relief may pose a problem.  If such .a  problem potentially  exists, it may
be necessary to measure the vertical  component  of  the  wind at the proposed
site,  and as close as possible to stack  height.  The starting threshold for
the vertical wind speed component should be less than  0.25 m/s.  Required
accuracy for the vertical  wind speed component  is  as specified in Section
6.1.1  for horizontal speeds.

6.1.3   Wind Fluctuations

       Determination of the on-site standard deviation of  wind fluctuations,
or derived standard  deviations of cross-plume concentrations  may be necessary
if dispersion parameters are being developed for use at a  specific site.  Since
the analytical  framework within which such wind fluctuations  measurements/
statistics are to be incorporated is  expected to be unique or applied on a
case-by-case basis,  approval by the permit granting authority is required
                                    49

-------
and no general  requirements regarding  specifications  are outlined  in this
guideline.   Considerable care  is  required  in  the  selection of wind instru-
ments and data logging systems, especially in the choice of sampling and
averaging times.   Thus,  response  characteristics  of wind sensors are
especially critical  [56,57],   Owners or operators designing programs incor-
porating these capabilities should  submit  a statement  from a qualified
consultant identifying the adequacy of such wind  system(s) within the
context of the overall  PSD ambient  monitoring program.

6.1.4  Vertical Temperature Difference

       Errors in measured temperature  difference  should not exceed 0.003
°C/m.

6.1.5  Temperature

       Errors in temperatures  should not exceed 0.5°C  if fog formation,
icing, etc., due to  water spray or  water vapor emitted from the facility
may be a problem. Otherwise,  errors should not exceed 1.0°C.

6.1.6  Humidity

       Atmospheric humidity can be  measured and expressed in several ways.
If the permit granting authority  determines that  a significant potential
exists for fog formation, icing,  etc., due to effluents from the proposed
facility, error in the selected measurement technique  should not exceed
an equivalent dewpoint temperature  error of 0.5°C.  Otherwise, errors in
equivalent dewpoint  temperature should not exceed 1.5°C over a dewpoint
range of -30°C to +30°C.

6.1.7  Radiation - Solar and Terrestrial

       The determination of Pasquill stability class may be based on
whether the solar radiation is termed  strong, moderate, or slight.  Stability
class can be determined  from sun  elevation and the presence, height, and
amount of clouds [46], or by using  a pyranometer  and/or net radiometer
during the daytime and a net radiometer  at night.  Such radiation-to-stability
relationships are expected to  be  site-specific, and the responsibility for
demonstrating their  accuracy lies with the permit applicant.   General  accuracy
for pyranometers and net radiometers used  in  a PSD monitoring network is
expected to be +5 percent.

6.1 .8  Mixing Height

       Mixing height data may  be  derived from NWS upper air data.  If
available data are determined  to  be inappropriate by the permit granting
authority,  such data may be obtained on-site  by the permit applicant [58]
The instrument system to be used  is not  specified in this guideline, but
its precision and resolution should not  exceed the limits associated with
NWS radiosonde systems [54,55].
                                    50

-------
6.1.9  Precipitation

       A recording precipitation  collector  should  have a resolution of
0.25 mm (0.01  inches)  liquid precipitation  per  hour at precipitation
rates up to 7.6 cm/hour.  Accuracy should be  within 10 percent of the
recorded value. A heated system should  be used  to  assure proper measure-
ment of frozen precipitation.  A  suitable windscreen should be used.

6.1.10  Visibility

        Visibility can be measured within 5 percent of true over visual
ranges of about 80 meters to 3 km with  available transmissometers.
Estimates can be based upon very  short  path lengths using other types of
equipment such as nephelometers [59].   At this  time, the combined use of
a multi-wavelength telephotometer, integrating  nephelometer and
particulate monitor, together with color photography, should prove most
helpful in documenting baseline visibility  related parameters.  These
as well as other components of a  visibility monitoring program, are
discussed in reference 51.  Reference 50 also contains much background
information.
                                    51

-------
                 7.  QUALITY ASSURANCE  FOR  METEOROLOGICAL DATA
     All equipment should receive an  appropriate  examination and calibration
prior to initial installation to assure the  acquisition  of  the maximum
amount of usable data within the error  limits  specified  herein.  Inspection,
servicing, and calibration of equipment must be scheduled throughout the
measurement program at appropriate intervals to assure at least 90 percent
data retrieval for each variable measured at sites where continuous air
quality monitors are being operated.  At remote sites, data retrieval
for measured variables should not fall  below 80 percent. In addition,
the joint frequency for the recovery  of wind and  stability  data should not
fall below 90 percent on an annual basis; missing data periods must not
show marked correlation with the various meteorological  cycles.

     Calibration of systems should be accomplished no less  frequently
tharn once every 6 months.  In corrosive or dusty  areas,  the interval
should be reduced to assure adequate  and valid data  acquisition.

     If satisfactory calibration of a measuring system can  be provided
only by the manufacturer or in special  laboratories, such as wind-tunnel
facilities, arrangements should be made for  such  calibrations prior to
acquisition of the equipment.  A parts  inventory  should  be  maintained at
a readily accessible location to minimize delays  in  restoring operations
after system failures.

     An independent meteorological audit {by other than  one who conducts
the routine calibration and operation of the network) should be performed
to provide an on-site calibration of instruments  as  well as an evaluation
of (a) the network installation, (b)  inspection,  maintenance, and calibra-
tion procedures, and logging thereof, (c) data reduction procedures,
including spot checking of data, end  (d) data  logging and tabulation
procedures.  The on-site visit (requiring as little  as 1 day in many
cases) should be made within 60 days  after the network is first in full
operation, and a written audit/evaluation should  be  provided to the
owner.  This report should be retained  by the  owner.  Any problems should
be corrected and duly noted as to action taken in an addendum to the
audit report.  A reproducible copy of the audit report and  the addendum
should be furnished with the source construction  permit  application.

     Such independent meteorological  audit-evaluations should be performed
about each 6 months.  The last such inspection should be made no more than
30 days prior to the termination of the measurement  program, and while the
measurement operation is in progress.

     The 1983 publication "Quality Assurance Handbook for Air Pollution
Measurement Systems:  Volume IV.  Meteorological  Measurements" [60]
should be consulted for more information. Major  sections in this volume
address (1) quality assurance of the  measurement  process, (2) methods for
judging the suitability of sensor siting, and (3) meteorological data
validation.
                                    52

-------
                           8.   DATA REPORTING
8.1  Air Quality Data Reporting

     A summary of the air quality data,  the  raw air  quality data, and
the quality assurance data discussed  in   Section 4.1.6  must be submitted
to the permit granting authority at the  time of submittal of the PSD
application.  There should be a prior agreement between the source and
the permit granting authority as to whether  the raw  data should be
submitted in addition to a summary of the  data.   Some sources may also
desire to submit data periodically to the  permit granting authority for
review to identify any problems in the data  as  they  occur.  Note that
this is not a requirement.  The applicant  and the permit granting authority
should have a prior agreement as to the  format  and procedure for the
data submission.  The air quality data should preferably be submitted in
SAROAD format and in a machine readable  form.   A printout of the contents
of the tape or cards should also be included.  All raw data not previously
submitted (i.e., calibration data, flow  rates,  etc.) should be retained
for 3 years and submitted upon request to  the permit granting authority.

     For continuous analyzers, at least  80 percent of the individual
hourly values should be reported by the  source  in any sampling period.
For manual  methods (TSP and particulate  pollutants), 80 percent of the
individual  24-hour values should be reported in any  sampling period.
This capture rate is important because of  the short  duration of a PSD
monitoring program.  In addition, there  should  not be a correlation
between missing data periods and expected  highest concentrations.

8.2  Meteorological Data Format and Reporting

     Because of the different data requirements for  different types of
analyses that might be used to evaluate  various facilities, there is no
fixed format that applies to all  data sets.   However, a generalization
can be made:  all meteorological  parameters  must be  collated in chrono-
logical order and tabulated according the  observation time, and be furnished
to the permit granting authority upon request.   All  meteorological variables
that have a SAROAD parameter code should be  submitted in SAROAD format.
All units should be in the SI system  (International  System of Units)
[61]. All input data (in the format required by the  analytical procedures
selected) used in, and all results of, the air  quality analyses must be
furnished to the permit granting authority upon request.
                                    53

-------
                   APPENDIX A






PROCEDURES TO DETERMINE IF MONITORING DATA WILL



       BE REQUIRED FOR A PSD APPLICATION

-------
                         1.  INTRODUCTION
     This appendix has been included in this guideline  to  aid  both the
reviewing authorities and the source applicants in determining if
monitoring data will  or will  not be required under PSD.   The major
considerations leading to a monitoring data decision  have been simplified
for presentation in this appendix.   This discussion represents the
Federal requirements and the minimum State program requirements.  It  is
important to identify the reviewing authority,  whether  it be the local
or State air pollution control agency, or the Regional  Office  of EPA  for
the final requirements.  For a complete discussion on the  complex PSD
issues, the reader is referred to the PSD regulations and the  preamble
discussion [5,7].

                2.  PSD PERMIT APPLICATION PROCEDURES

     Figure A-l shows a simplified organizational  overview of  the proce-
dures to be followed in the preparation of a PSD permit application.
Figure A-l  shows that these procedures are divided into seven  parts.
This division is only for illustrative purposes within  this appendix  and
is intended only to separate the complex procedures into distinct subparts.
Within the Part 1-Source Applicability Determination, both candidate  new
and modified major sources are reviewed to see  if PSD review will apply.
The Part 2-Pollutant Applicability Determination shows  those pollutants
emitted from subject .sources that may or may not be exempted from further
analysis.  The Part 3-BACT Analysis is to ensure the  application of
best available control  technology (BACT) on subject pollutants.  Air
quality analysis covered in Part 4 includes both modeling  and  monitoring
data considerations for certain BACT pollutants.   The Part 5-Source Impact
Analysis is to demonstrate that the proposed emissions  would not cause
or contribute to a violation of any NAAQS or PSD increment.  The Part 6-
Additional  Impact Analysis is to ensure that the proposed  emissions
increases would not impair visibility, or impact on soils  and  vegetation.
Finally, Part 7 represents the complete PSD application which  transfers
to the permit granting authority the results of all the analysis from
the first six parts.  Normally, the source applicant  will  supply all  the
information including the BACT and air quality  analyses to make the
necessary determinations.  Each of these seven  parts  is discussed below
in Sections 2.1-2.7.   Section 3 contains flow diagrams  and discussion
of the first four parts that pertain to the decision  whether monitoring
data will or will  not be required.

2.1  Part 1 - Source Applicability Determination

     The first step in the PSD program is to determine  if  a proposed  new
or modified source is subject to the PSD regulations.  The first test
for PSD applicability is that the proposed construction must involve  a
major stationary source.  Thus, the candidate construction must either
be a proposed new major stationary  source or involve  the modification of
an existing major stationary source.  The criteria in determining whether
                                   A-l

-------
 Part 1 - Source Applicability Determination
 Part 2 - Pollutant Applicability Determination
           Parts-BACT Analysis
    Part 4 - Ambient Air Quality Analysis
                     l
       Part 5 - Source Impact Analysis
      Part 6 - Additional Impact Analysis
      Part 7 - Complete PSD Application
Figure A-1. Simplified procedures for the preparation of a PSD permit application.
                       A-2

-------
the affected source is sufficiently large (in  terms  of emissions)  to be
a new major stationary source or major modification  is based on considera-
tion of its potential  to emit at rates exceeding  certain  threshold values.
Potential  to emit is the capability at maximum design  capacity to  emit a
pollutant after the application of all required air  pollution control
equipment, taking into account all  federally enforceable  requirements
restricting the type or amount of source  operation.  A major modification
is generally a physical  change in or a change  in  the method of operation
of a major stationary source which would  result in a significant net
emissions increase for any regulated pollutant.   (There are several
changes that are exempted from being considered a major modification.)
Also, the proposed source or modification must locate  in  a PSD area—an
area designated as "attainment" or "unclassifiable."   If  the proposed
source or modification would meet certain tests and  commence construction
in a continuous fashion at the proposed  site within  a  reasonable time, a
PSD permit under the August 7, 1980 regulations would  not be necessary.
Lastly, there are specific new sources and modifications  that are exempted
from PSD review.  All  of the above considerations are  explained in more
detail in Section 3 of this appendix.

     If it is determined that a new source or  modification is subject to
the PSD regulations, then one must proceed to  the Part 2-Pollutant
Applicability Determination in order to  learn  how the  pollutant-specific
requirements of PSD may apply.

2.2  Part 2 - Pollutant Applicability Determination

      If a source applicant has determined that a proposed new source or
modification would be subject to the PSD  requirements, then the applicant
must assess whether the pollutants the project would emit are subject to
PSD.  If a new major stationary source emits pollutants for which the
area it locates in is designated nonattainment, then the  source is
exempt from PSD review for those pollutants.   These  sources must,
however, meet the applicable requirements of new  source review (NSR) for
each nonattai nment pollutant.  If a major construction proposed for a
PSD area involves only changes for nonattainment  pollutants, then the
source is not subject to PSD.  These sources must meet the appropriate
nonattainment NSR under the SIP for the  pollutant.   Once  the question of
NSR jurisdiction is resolved, then the PSD review applies to significant
emissions increases of regulated air pollutants.

     Specific numerical  cutoffs which define what emissions increases
are "significant" are shown in Table A-l.   These  emissions rates will be
used for pollutants to be emitted from a  PSD source  unless the new
source or modification is to be located  within 10 km of a Class I area
[1]. For these situations, the proposed  source or modification must be
prepared to demonstrate that it would not have a  significant impact with
respect to a Class I area.  A Class I significant impact  is defined as
one microgram per cubic meter (ug/m^ or more for  a 24-hour average.
Further details on how the significant emission rates  in  Table A-l were
derived may be found in the preamble discussion of the PSD regulations
[51.
                                   A-3

-------
               TABLE A-l.  SIGNIFICANT EMISSIONS RATES
            'Pollutant                   Emissions Rate (tons/year)

Carbon monoxide                                  100
Nitrogen oxides                                   40
Sulfur dioxide                                    40
Particulate Matter                                25 (TSP)
Particulate Matter                                15 (PM^o)
Ozone (volatile organic compounds)                 40
Lead                                               0.6
Asbestos                            -               0.007
Beryllium                                          0.0004
Mercury                                            0.1
Vinyl chloride                                     1.0  _%
Fluorides                                          3
Sulfuric acid mist                                 7
Total reduced sulfur (including HgS)               10
Reduced sulfur (including H2$)                     10
Hydrogen sulfide                                  10
                                 A-4

-------
     If the emissions from a new source will  be  significant,  or  if  the
net emissions increase from a proposed modification  will be significant,
then one must proceed to the Part 3-BACT Analysis  for  these pollutants.

2.3  Part 3 - BACT Analysis

     Any major stationary source or major modification subject to PSD
must conduct an analysis to ensure application of  best available control
technology (BACT) for all applicable pollutants.   During each analysis,
which will  be done on a case-by-case basis, the  reviewing authority will
evaluate the energy, environmental, economic, and  other costs associated
with each alternative technology.   The reviewing authority will then specify
an emissions limitation for the source that reflects the maximum degree
of reduction achievable with all  these concerns  in mind for each pollutant
regulated under the Act.  In no event can an  emission  limitation be
required which would be less stringent than any  applicable standard of
performance under 40 CFR Parts 60 and 61.

     After the BACT determination, the source must then investigate the
need for each pollutant subject to BACT (BACT pollutant) to also undergo
the remaining analyses for this pollutant.

2.4  Part 4 - Ambient Air Quality Analysis

     Each application by a PSD source or modification  must contain an
air quality analysis for each BACT pollutant  to  demonstrate that its new
pollutant emissions would not violate either  the applicable NAAQS or the
applicable PSD increment.  This analysis ensures that  the existing  air
quality is better than that required by national standards and that
baseline air quality is not degraded beyond the  applicable PSD increment.
Two narrow exemptions to this requirement are specified in the regulations
and involve certain existing sources with low BACT emissions  and sources
of temporary emissions meeting certain criteria.

     In making the above determinations, many PSD  sources must first
assess the existing air quality for each applicable  air pollutant that
it emits in the affected area.  The requirement  to monitor existing air
quality may not apply to (a) pollutants for which  the  new emissions
proposed by the applicant would cause impacts less than the significant
monitoring concentrations (Table A-2), or (b), situations where the
background concentration of the pollutant is  below the significant
monitoring values.  This exemption should not be used  when there is an
apparent threat to an applicable PSD increment or  NAAQS based on modeling
alone or when there is a question of adverse  impact  on a Class I area.
When monitoring data are required, the applicant must  provide ambient
montioring data that represent air quality levels  in the year's period
preceding the PSD application.  Where existing data  are not judged
representative or adequate, then the applicant must  conduct its own
monitoring program.  Typically, monitoring data  are  used  by  applicants
to support or extend the assessment made with air  quality dispersion
model ing.
                                   A-5

-------
            TABLE A-2.   SIGNIFICANT MONITORING CONCENTRATIONS
           Pollutant
Air Quality Concentration (ug/m^)
   and Averagi ng Time
 Carbon monoxide
 Nitrogen dioxide
 Sulfur dioxide
 Particulate Matter
 Particulate Matter
 Ozone
 Lead
 Asbestos
 Beryl!ium
 Mercury
 Vinyl chloride
 Fluorides
 Sul furic acid mist
 Total reduced sulfur (including
 Reduced sulfur (including H2S)
 Hydrogen sulfide
     575  (8-hour)
      14  (Annual )d
      13  (24-hour)
      10  (24-hour) for TSP
      10  (24-hour) for PM10
     a
       0.1  (3-month )d
     b
       0.001  (24-hour)e
       0.25  (24-hour)
      15  (24-hour)
       0.25  (24-hour)
     b
     c
     c
       0.2  (l-hour)e
aNo specific air quality concentration for ozone is prescribed.   Exemptions
 are granted when a source's VOC emissions are < 100 tons/year.
No acceptable monitoring techniques available at this  time.   Therefore,
 monitoring is not required until acceptable techniques are available.
cNo acceptable monitoring techniques available at this  time.   However,
 techniques are expected to be available shortly.
     averaging times are corrected to be consistent with  the  averaging  time
 of the standard.
eThese concentrations are corrected from the previous printing and are
 approximately five times the minimum detectable concentrations.   These
 concentrations are consistent with other values in this  table.
                                   A-6

-------
     In addition to the above discussion,  EPA  in  general intends to limit
the application of air quality models  to a  downwind distance of 50
kilometers.  This is because dispersion parameters commonly in use are
based on experiments relatively close  to sources, and extending these
parameters to long downwind distances  results  in  great uncertainty as to
accuracy of the model  estimates at  such distances.  EPA does not intend
to analyze the impact of a source beyond the point where the concentrations
from the source fall below certain  levels  (generally based on Class I
increments) shown in Table A-3. However,  since the 1977 Clean Air Act
Amendments provide special  concern  for Class I areas, any reasonably
expected impacts for these areas must  be considered irrespective of the
50 km limitation on the above significant  values.*

2.5  Part 5 - Source Impact Analysis

     The proposed source or modification must  demonstrate that significant
net emissions increases {including  secondary emissions and fugitive
emissions), would not cause or contribute  to air  pollution in the violation
of any NAAQS or any applicable maximum allowable  increase over the
baseline concentration in any area.

2.6  Part 6 - Additional Impact Analysis

     An applicant is also required  to  analyze  whether its proposed
emissions increases would impair visibility, or impact on soils or
vegetation.  Not only must the applicant look  at  the direct effect of
source emissions on these resources, but it also  must consider the
impacts from general commercial, residential,  industrial and other
growth associated with the proposed source  or modification.

2.7  Part 7 - File Complete PSD Application

     After completion of the proceeding analyses, the source may submit
a PSD application to the permit granting authority.  The application,
after being judged complete and being  reviewed for proper determination
of applicability, BACT, and air quality impacts,  must undergo adequate
*It should be noted that there  are  three  separate and distinct sets of
values which are considered "significant" within the PSD program:

     (a)  Significant emissions rates;
     (b)  Significant monitoring concentrations; and
     (c)  Significant ambient impacts  (including the specific significant
          Class I area impacts).

As pointed out, each set of values  has  a  different application, and
therefore, this guideline has been  worded to clarify the appropriate
values to be used while assessing the  need  to collect monitoring data.
                                   A-7

-------
           TABLE A-3.   SIGNIFICANT AMBIENT AIR  QUALITY  IMPACTS
Pollutant
S02
TSP
PM10
N02
CO
Averaging Time
Annual 24-Hour 8-Hour 3-Hour 1 Hour
1 yg/m3 5 yg/m3 — 25 yg/m3
1 yg/m3
1 yg/m3 5 yg/m3
1 yg/m3
0.5 mg/m3 -- 2 mg/m3
NOTE:  This table does not apply  to  Class  I areas.  A significant impact
       for Class I areas  is 1  \>g/w  on  a 24-hour basis for PM^j and S02.
                                  A-8

-------
public participation.  The regulations solicit and  encourage  participa-
tion by the general  public, industry,  and  other affected  persons  impacted
by the proposed major stationary source or major modification.  Specific
public notice requirements, including  a public comment  period and the
opportunity for a public hearing must  be met before the PSD review agency
takes final action on a PSD application.   The public  notice must  indicate
whether the reviewing authority has proposed approval,  denial, or condi-
tional approval of the proposed major  source or major modification.
Consideration is given to all  comments received provided  they are relevant
to the scope of the review.

     The source shall also submit all  information necessary to perform
any analysis in Parts 1-6 above or make any determinations required in
Parts 1-6.  Such information shall  include (a)  a description of the
nature, location, design capacity,  and typical  operating  schedule of the
proposed source or modification, including specifications and drawings
showing its design and plant layout, (b) a detailed schedule  for construc-
tion of the proposed source or modification, and (c)  a  detailed descrip-
tion as to what system of continuous emission reduction is planned for
the proposed source or modification, emission estimates,  and any other
information necessary to determine  that best available  control technology
would be applied.  The proposed source or  modification  shall also provide
information on (a) the air quality  impact  of the proposed source or
modification, including meteorological  and topographical  data necessary
to estimate such impact, and (b) the air quality impacts, and the nature
and extent of any or all general commercial, residential, industrial,
and other growth which has occurred since  August 7, 1977  in any area the
proposed source or modification would  affect.
                                   A-9

-------
                   3.  DECISIONS FOR MONITORING  DATA  REQUIREMENTS

      Figure A-l  and the discussion that followed  in  Section  2  provided
an overview of the various activities relating  to  a PSD  permit  application.
This section will  go into more detail  on those activities that  need to
be considered in deciding if air quality monitoring data will be required.

     It should be noted that the procedures  described in this appendix
do not include any details on how the modeling  analyses  are to  be conducted
but only indicate at what points (boxes) the results  of  such  analyses
are necessary.  Also, while these procedures lead  to  a determination of
when air quality monitoring is likely to be  required, they do not lead
to a decision as to when meteorological  monitoring is necessary (for
model  input). Guidance on the requirements and  procedures for conducting
modeling analyses is contained in reference  15.  Section 5 of this
guideline describes general  meteorological monitoring requirements, and
reference 62 also provides further guidance  on this subject.

     Figures A-2 and A-3 show various steps  that must be made for a
proposed PSD source or modification in order to  assess how the  monitoring
data requirement might apply.   The decisions in  these flow diagrams must
be applied separately for each regulated pollutant that  would be emitted
from a proposed source or modification.   Boxes 1-14 apply to  Figure A-2
and boxes 15-29 apply to Figure A-3

Box 1.  Is proposed source a major stationary source  or  major modification
        locating in a PSD area?

     A major stationary source is defined as any one  of  28 source categories
(Table A-4)  which emits, or has the potential to emit, 100 tons per year
or more of any pollutant regulated under the Act.   In addition, the
definition includes any other stationary source  which emits, or has the
potential to emit, 250 tons per year or more of  any regulated pollutant.
Finally, major stationary source also means  any  physical change occurring
at a stationary source (which prior to the change  is  not major) if the
change by itself would be major.  That is, the change itself would
result in an equivalent stationary source which  would emit 100  tons per
year or more for any pollutant regulated under the Act for any  one of
the 28 source categories (Table A-4), or 250 tons  per year for  any other
stationary source.  The pollutants regulated under the Act were shown in
Part 2-Pollutant Applicability Determination.

     A stationary source generally includes  all  pollutant-emitting
activities which belong to the same industrial grouping, are  located on
contiguous or adjacent properties, and are under common  control.  Pollutant
activities which belong to the same major group  as defined in a standard
industrial classification scheme developed by the  Office of Management
and Budget are considered part of the same industrial  grouping.

     The rest of the PSD size applicability  for  proposed new stationary
sources is simply that the candidate source  would  be  a major  stationary
                                   A-10

-------
 1.  Is proposed source
    a major stationary source or
    a major modification locating
    in a PSD area?
                                                                                                      1
                                                                                                       Part 1 -
                                                                                                       Source Applicability
                                                                                                       Determination
      3.  Is construction proposed
YES /     ior an area which is designated^ NO
         nonattainment area ior the
         regulated pollutant? *
                                                                                                      J
              5.  Is proposed source
        '   '     or modification within
                 10 km of a Class I area?/
                                                                  YES
                                                                      6.  Class I area
                                                                         screening procedure
                                                                            7.  More  refined model
                                                                               (optional).  Note:  May
                                                                               require gathering  of
                                                                               meteorological data.
                    9.  Are new emissions or net      \
                 .      emissions increase of the        \
                 \     regulated pollutant > Table A-1?/
                                                        /8.  Will the proposed source^
                                                    '    /     or modification impact
                                                        \    on a Class I area?
                            YES
                                              YES
                        / 11. Is proposed construction a   \   _
                    	(     relocation of a portable      •-—
                        \    facility with previous permit?
                     /12. Are there potential impacts    \  yEt.

                    \    °'
on a Class I area, or areas
  known increment violation?
Part 2 -
Pollutant Applicability
Determination
                                                           •P
                                                                    14. Apply BACT
                                                                            ]
   Part 3 -
   BACT Analvsis
 * Procedures are to be repeated for
   all regulated pollutants which would
   be emitted by the proposed construction.
                 (
                 c
Part 4
• Ambient Air Quality Analysis

Part 3
Part 6
- Source Impact Analysis
- Additional Impact Analysis

Part 7
- Complete PSD Application
       Figure A-2.  Procedures  used to  determine the monitoring  data requirement.
                                                      A-ll

-------
                                                                 Part 1 - Source Applicability Determination
                                                                                JL
                                                                | Part 2 . Pollulanl Applicability Determination
                                                                                 I  ~
                                                                | Part 3 -  BACT Analysis"]
                                                              NO/
                                                                ' 15. Are the allowable emissions or the    \
                                                                    net emissions increase temporary,
                                                                    impacting no Class I area, or impacting
                                                                    no area where the PSD increment
                                                                    is violated!                         /
                                                                                                             , YES
                                        16.  Wifl the proposed    \
                                            source or modification
                                            emil VOQ           /
NO,
H8.  Is there an apparent threat >
     to the NAAQS, or is there
     a potential adverse  impact
     on a Class I area)
                                   LYES
                                  YES
                                   ' 19.  Will proposed source or     \
                                        modification perform post-    \
                                        approval monitoring in lieu     V~
                                        of preconstruction monitoring /
                                        data?         	/
                                                                                20. Estimate existing air quality.
                                                                                    Note: May require gathering
                                                                                    of meteorological data.
21.  Estimate air quality impacts of
    proposed construction.
    •  Use screening procedure
      or more refined model
    •  Use 'good engineering practice"
    •  Consider 50  ton/year exemption
                                                                                         22.  Is the existing air
                                                                                             quality < Table A-2!
                                 -YES
                                                                NO/23. Are the air quality   \yjs
                                                                          impacts < Table A-2? /
                                         YES /2S. Are proposed emissions
                                                 a criteria pollutant or VOC?
                                                                                              24.  Is there an apparent threat to
                                                                                                  the PSD increments or NAAQS. \YES
                                                                                                  or is there a potential adverse
                                                                                                  impact on a Class I area!
                                                                     ,26.  Is there an approved
                                                                 NO /
                                                                 1   '       monitoring technique
                                                                            available?
Part 4 -
Ambient
Air Quality
Analysis
                          27.  Preconstruction monitoring data required.
                              •  Use representative air quality data
                              •  Monitor (source specific)
                                                                    28. No preconstruction
                                                                        monitoring data required
                      29. Preconstruction monitoring
                          data may be required
                                                                  Part 5 - Source Impact Analysis
                                                                  Part 6- Additional Impact Analysis
                                                                  Part 7- Complete PSD Application
                                       FIGURE A-3. PROCEDURES USED TO DETERMINE THE MONfTORINC DATA REQUIREMENT.
                                                                            A-12

-------
                 TABLE A-4.   MAJOR STATIONARY SOURCES
1.  Fossil-fuel  fired steam electric  plants  of more  than 250,000,000
     British thermal  units per hour heat input
2.  Coal cleaning plants (with thermal  dryers)
3.  Kraft pul p mills
4.  Portland cement plants
5.  Primary zinc smelters
6.  Iron and steel  mill  plants
7.  Primary aluminum ore reduction plants
8.  Primary copper smelters
9.  Municipal  incinerators capable of charging more  than 250 tons of
     refuse per day
10. Hydrofluoric acid plants
11. Sulfuric acid plants
12. Nitric acid plants
13. Petroleum refineries
14. Lime plants
15. Phosphate rock processing plants
16. Coke oven batteries
17. Sulfur recovery plants
18. Carbon black plants  (furnace process)
19. Primary lead smelters
20. Fuel conversion plants
21. Sintering plants
22. Secondary metal production plants
23. Chemical process plants
24. Fossil-fuel  boilers  (or combinations thereof)  totaling of more than
      250,000,000 British thermal  units per  hour heat  imput
25. Petroleum storage and transfer units with  a total  storage capacity
    exceeding 300,000 barrels
26. Taconite ore processing plants
27. Glass fiber processing plants
28. Charcoal production  plants
                                 A-13

-------
source in terms of its potential  to emit.   The  applicability  rules for
determining whether a major modification would  occur  are more complex.

     A "major modification" is generally a  physical change  in or a
change in the method of operation of a major  stationary source which
would result in a significant net emissions increase  in the emissions of
any regulated pollutant.   In determining if a proposed increase would
cause a significant net increase  to occur,  several detailed calculations
must be performed. First,  the source owner  must quantify the  amount of
the proposed emissions increase.   This amount will generally be the
potential  to emit of the new or modified unit.  Second, the owner must
document and quantify all  emissions increases and  decreases that have
occurred or will  occur contemporaneously (generally within  the past five
years) and have not been evaluated as part  of a PSD review.  The value
of each contemporaneous decrease  and increase is generally  determined by
subtracting the old level  of actual  emissions from the new  or revised
one.  Third, the  proposed  emissions  increase  and the  unreviewed contem-
poraneous changes must then be totalled.  Finally, if there is a resultant
net emissions increase that is larger than  values  specified in Table
A-1, the modification is major and subject  to PSD  review.

     Certain changes are exempted from the  definition of major modification.
These include: (a) routine maintenance, repair  and replacement; (b) use
of an alternative fuel  or  raw material  by revision of an order under sections
2(a) and (b) of the Energy Supply and Environmental Coordination Action
of 1974 (or any superseding legislation); (c) use  of  an alternative fuel
by reason of an order or rule under section 125 of the Clean Air Act;
(d) use of an alternative  fuel  at a  steam generating  unit to the extent
it is generated from municipal  solid waste; (e) use of an alternative
fuel or raw material  which the source was capable  of  accommodating; before
January 6, 1975 or which the source  is approved to use under any permit
issued under 40 CFR 52.21 , or under  regulations approved pursuant to 40
CFR 51.24; and (f) an increase in the hours of  operation, or the production
rate.  The last two exemptions, (e)  and (f),  can be used only if the corres-
ponding change is not prohibited  by certain permit conditions established
after January 6,  1975.

     If the size  of a proposed source or modification thus  qualifies as
major, its prospective  location or existing location  must also qualify
as a PSD area, in order for PSD review to apply.   A PSD area is one
formally designated by the state  as  "attainment" or "unclassifiable" for
any polluant for  which a national  ambient air quality standard exists.
This geographic applicability test generally  does  not take  into account
what new pollutant emissions caused the construction  to be  major.  It
looks simply at whether the source is major for any pollutant and will
be located in a PSD area.   The one exception  is that  if a major stationary
source emits only nonattainment pollutants, then no PSD review would
apply.

     If a proposed source  or modification would be subject  to PSD review
based on size, location,  and pollutants emitted, it still  may escape the
PSD review requirements under certain grandfather  provisions under 40 CFR
                                   A-14

-------
.52.21(1).   For example, a  proposed  source or modification that was not
 subject to  the 1978  PSD rules and had received all necessary Federal,
 State and  local  air  permits before  August 7, 1980, would not be subject
 to the 1980 regulations.   (See the  PSD regulations for other exemptions.)

      Finally,  the  PSD  regulations contain some specific exemptions for
 some forms  of  source construction.  The requirements of the PSD regula-
 tions do not apply to  any  major  stationary source or major modification
 that is (a) a  nonprofit health or educational institution (only if such
 exemption  is requested by  the governor), or (b) a portable source which
 has already received a PSD permit and proposes relocation, or the source
 or modification would  be a major stationary source or major modification
 only if fugutive emissions, to the  extent quantifiable, are considered
 in calculating the potential to  emit of the stationary source or modifi-
 cation and  the source  does not belong to any of the categories listed in
 Table A-4.

 Box 2.  No  PSD permit  needed.

      If the source has met the appropriate deadlines for construction;
 and is not  a major stationary source, a major modification, is not
 located in  a PSD area, or  is not subject to the specific exemptions
 mentioned above, the PSD program is not applicable, and therefore, no
 PSD permit  is  needed.

 Box 3.  Is  construction proposed for an area which is designated
         nonattainment  area for the  regulated pollutant?

      If the project  is a major stationary source or a major modification,
 the prospective location must also  qualify as a PSD area in order for
 the PSD review to  apply.   A PSD area is defined as an area formally
 designated  by  the  State as "attainment" or "unclassifiable" for any pollu-
 tant for which a NAAQS exists.   An  area not classified as either "attain-
 ment" or "unclassifiable"  would be  classified as "nonattai nment".  If the
 proposed construction  is in a nonattainment area for any pollutant, pro-
 ceed to box 4  for  that pollutant; for all other regulated pollutants,
 proceed to  box 5.

 Box 4.  No  further PSD analysis  for that pollutant.

      If the proposed major stationary source or major modification will
 emit pollutants from an area that has been designated as "nonattainment",
 then the proposed  source or modification is exempt from further PSD
 review for  only those  pollutants.   However, the proposed source or
 modification must  meet the applicable preconstruction requirements for
 each nonattainment pollutant.  (See 40 CFR 51.18 and 40 CFR 52.24.)

      The pollutant applicability determination would be continued for
 all other  regulated  pollutants (except nonattainment pollutants) emitted
 by a proposed  major  stationary source or major modification by proceeding
 to box 5.
                                   A-15

-------
Box 5.  Is proposed source or modification within 10  km  of a  Class  I
        area?

     The PSD regulations [40 CFR 51.24(b)(23)(iii)  and 40  CFR 52.21(b)(23)
(iii)] require that a proposed source or modification, which  plans  to
construct within 10 km of a Class I  area must demonstrate  that if it
would not impact the area, (less than 1  yg/m^)  even if the proposed
emissions are below the applicable significant  emissions rates listed in
Table A-l.  If the proposed source or modification  is within  10 km  of a
Class I area, proceed to box 6; if not,  proceed to  box 9.

Box 6.  Class I area screening procedure.

     If the proposed source or modification is  within 10 km of a Class I
area, then the screening procedures  described in reference 62 may be
used to estimate the impact on the Class I area.   This screening procedure
is based on a simple but conservative model  for estimating each concentra-
tion due to the emissions from the proposed source  or modification.

Box 7.  More refined model (optional).

     A proposed source or modification may choose not to accept or  use
the concentration estimates derived  from the screening procedures in box
6, and may elect to use a more refined model  which  would more adequately
reflect the impact on the Class I area from the proposed source or  modifi-
cation.   It should be emphasized that in order  to perform  a refined
modeling analysis, it may be necessary to collect 1 year of on-site
meteorological data for the model  input  if an adequate amount of represen-
tative data are not already available.  The application of any model used
in this  analysis must be consistent  with reference  15 as discussed  in
section 5.1.  The application of any different  model  must  be  approved by
EPA in order to avoid any delays in  the  processing  of the  permit applica-
tion.  Applicants should consult with the reviewing authority before
investing considerable resources in  the  use of  the  different  models.
Therefore, the documentation and specific description of the  model  should
be provided to the reviewing authority before the results  are submitted.

     The concentration estimates from the screening procedure or the refined
model, are subsequently used in the  Part 4-Ambient  Air Quality  Analysis
and Part 5-Source Impact Analysis.

Box 8.  Will the proposed source or  modification impact on a  Class  I
        area?

     If a proposed source or modification is within 10 km  of  a  Class I
area, the proposed source or modification must  be prepared to demonstrate
for each regulated pollutant it would emit that there would be  no signifi-
cant impact on the Class I area.  Significant impact  is defined in  the
PSD regulations [40 CFR 51.24(b)(23)(iii) and 40 CFR  52.2K b)(23)( iii)]
as 1 microgram per cubic meter (yg/rrP) or more, 24-hour average.

Box 9.  Are new emissions or net emissions increase of the regulated
        pollutant  >Table A-l?
                                   A-16

-------
     If the proposed source or modification  is  not  within  10 km of a
Class I area, or if the proposed  source  is within 10  km of a Class I
area and has no significant impact on  the Class I area, then the emissions
for each pollutant from the proposed  source  of  modification are compared
to the significant emissions rates in  Table  A-l.

Box 10.  No further analysis for  that  pollutant.

     If the emissions from the proposed  source  or modification are not
significant as defined in Table A-l, no  further analysis is required for
that pollutant.  However, a similar review must be  performed for all
other regulated pollutants by  proceeding to  box 5 for the  next pollutant.

Box 11.  Is proposed construction a relocation  of a portable facility
         with previous permit?

     This question is actually an applicability question that is normally
considered under the Part 1-Source Applicability Determination.  However,
there are certain other questions (see boxes 3, 5 and 8 of Figure A-2)
which are normally asked under pollutant applicability that are also
germane to permitting a portable  facility relocation.  Thus, the reason
for including box 11 in Part 2.

     The source must be a portable facility  which has previously received
a permit under the PSD regulations, the  owner proposes to  relocate the
facility, and emissions at the new location  would be temporary (not
exceeding its allowable emissions).   If  the  facility meets these require-
ments, then proceed to box 12; if not, proceed  to box 14.

Box 12.  Are there potential  impacts on  a Class I area, or areas of known
         increment violation?

     The emissions from the portable source  should  not exceed its
allowable emissions, and the emissions from  the temporary  source should
impact no Class I area and no  area where an  applicable increment is known
to be violated.  If there are  potentially adverse impacts  on a Class I
area, or significant impacts on areas  of known  increment violation,
proceed to box 14; if not, proceed to  box 13.

Box 13.  No PSD permit required.

     If there are no potential impacts on a  Class I area,  or areas of
known increment violation, no  PSD permit is  required.

Box 14.  Apply BACT.

     "Best available control  technology" means  an emissions limitation
(including a visible emission  standard)  based on the maximum degree of
reduction for each pollutant subject to  regulation  under the Act which
would be emitted from any proposed major stationary source or major
modification which the Administrator,  on a case-by-case basis, taking
into account energy, environmental, and  economic impacts and other
costs, determines is achievable for such source or  modification through
application of production processes or availabl e methods,  systems, and
                                   A-17

-------
techniques, including fuel  cleaning or treatment  or innovative fuel
combustion techniques for control  of such  pollutant.   In  no  event  shall
application of best available control  technology  result in emissions  of
any pollutant which would exceed the emissions  allowed  by any  applicable
standard under 40 CFR Parts 60 and 61.  If the  Administrator determines
that technological  or economic limitations on the application  of measure-
ment methodology to a particular emissions unit would make the imposition
of an emissions standard infeasible, a design,  equipment, work  practice,
operational standard, or combination thereof, may be prescribed instead
to satisfy the requirement for the application  of best  available control
technology. Such standard shall, to the degree  possible,  set forth the
emissions reduction achievable by implementation  of such  design, equipment,
work practice or operation, and shall  provide for compliance by means
which achieve equivalent results.

Box 15.  Are the allowable emissions or the net emissions increase
         temporary, impacting no Class I area,  or impacting  no  area
         where the PSD increment is violated?

     Temporary emissions are defined as emissions from  a  temporary
source that would be less than 2 years in  duration, unless the Adminis-
trator determines that a longer time period would be appropriate.  If
all of the conditions above are not met, proceed  to box 16;  if  they are
met, proceed to Part 7-Complete PSD Application.

Box 16.  Will the proposed source or modification emit  VOC?

     If the proposed source or modification will  emit VOC, proceed to
box 17; if not, proceed to box 20.  Also proceed  to box 20 if  the
pollutants are TSP, PMio, S02, CO, NOe, or Pb.
Box 17.  Are VOC emissions < Table A-2?

     If the VOC emissions rates from the proposed  source  or modification
are less than the value in Table A-2 (100 tons/year),  proceed  to box 18;
if not, proceed to box 19.

Box 18.  Is there an apparent threat to  the  NAAQS,  or  is  there a potential
         adverse impact on  a Class I area?

     If the projected air quality after  construction is equal  to or
greater than 90 percent of the NAAQS, a  threat  to  the  NAAQS would generally
exist. Potential adverse impacts on a Class  I area must be determined on
a case-by-case basis by the permit granting  authority.  Therefore, if
there is an apparent threat to the NAAQS, or if there  are potential
adverse impacts on a Class  I area, then  proceed to box 19; if not,
proceed to box 20.
                                   A-18

-------
Box 19.  Will proposed source modification perform postapproval  monitoring
         in lieu of preconstruction monitoring data?

     The PSD regulations [40 CFR 51.24(m)(1)(v)  and 40  CFR  52.21(m)(l)
(vi)] give special  considerations regarding ozone monitoring  data  to  new
or modified sources of volatile organic compounds which have  satisfied
all conditions of 40 CFR 51, Appendix A, section IV.  This  section
generally requires affected sources to meet lowest achievable emission
rate limitations, secure emissions offsets which provide an overall net
air quality improvement, and ensure all other major sources in the same
State are in compliance with the applicable SIP.   If  a  proposed  source
or modification has met all of the above conditions for VOC,  then  the
proposed source or modification may provide postapproval  monitoring data
for ozone in lieu of providing preconstruction data.  Postapproval
monitoring data are data collected after the date of  approval  of the  PSD
application.  However, in no case should the postapproval monitoring  be
started later than 2 years after the start-up of the  new source  or
modification.

     If the proposed source or modification will  provide postapproval
monitoring, proceed to the Part 5-Source Impact Analysis; if  not,
proceed to box 20 for the remainder of the ambient air  quality analysis.

Box 20.  Estimate existing air quality.

     The proposed source or modification must perform an initial analysis
to estimate the existing air quality concentrations.  The screening pro-
cedures described in reference 62 may be used.  The screening procedures
are based on simple models for estimating air quality due to  the emissions
from existing and approved but not yet built sources.  A proposed  source
or modification may choose not to accept or use  the concentration  estimates
derived from the screening procedure above, and may elect to  use a more
refined model which would more adequately reflect the impact  from  existing
sources.  It should be emphasized that in order to perform  a  refined
modeling analysis, it is generally necessary to  collect 1 year of  on-site
meteorological data for the model input.  The application of  any model
used in this analysis must be consistent with  reference 15  as discussed
in section 5.1.  The application of any model  should  be approved by the
permit granting authority to avoid any future  delays  in the processing of
the permit application.  Therefore, the documentation of the  specific
description of the model  should be provided to the permit granting
authority before the results are submitted.

     The concentration estimates from the screening procedure or the
optional refined model will be used in the remaining  portions of the
ambient air quality analysis.
                                   A-19

-------
Box 21.  Estimate air quality impacts of proposed construction.

     The proposed source or modification must  estimate  its  air quality
impacts to demonstrate that its new pollutant  emissions would not  violate
either the applicable NAAQS or the applicable  PSD increment.  The  proposed
source or modification must use the screening  procedures or more refined
model, consider "good engineering practice"  for stack height, and  consider
the TSP and S02 increment exclusion for Class  II areas  under 50 tons  per
year exemption.  These factors are discussed in more  detail below.

     (a)  Screening procedure or more refined  model.

          If the proposed source or modification used the screening
procedure or more refined model  in box 6 or 7  previously to estimate  the
impact, then those results may be used in this impact analysis.  If the
screening procedure or more refined model  was  not previously determined,
then the screening procedures described in reference 62 may be used.
This screening procedure is based on a simple  model  for estimating each
concentration due to the emissions from the proposed  source or modification,
A proposed source or modification may choose not to accept  or use  the
concentration estimates derived from the screening procedure above, and
may elect to use a more refined model  which  would more  adequately  reflect
the impact from the proposed source or modification.  It should be
emphasized that in order to perform a refined  modeling  analysis, it is
generally necessary to collect 1 year of on-site meteorological data  for
the model input.  The application of any model  used in  this analysis
must be consistent with reference 15 as discussed in  Section 5.1.  The
application of any model  should be approved  by the permit granting
authority to avoid any future delays in the processing  of the permit
application.  Therefore, the documentation and specific description of
the model should be provided to the permit granting  authority before  the
results are submitted.

          The concentration estimates from the screening procedure or
the optional refined model will  be used in the remaining portions  of  the
ambient air quality analysis.

     (b)  "Good engineering practice" (GEP)  for stack height.

          The 1978 PSD regulations [1] provide for requiring GEP in the
impact analysis for stack heights.  The degree of emission  limitations
required for the control  of any air pollutant  would not be  affected by
stack heights (in existence after December 31, 1970)  as exceeds good
engineering practice, or any other dispersion  techniques implemented
after then.

     (c)  Consider 50 tons per year exemption.

          The PSD regulations [40 CFR 51.24(1) (7) and 40 CFR 52.21(1) (7)]
as they apply to a major modification exempt PMio and S02  from the Class
II increment consumption review if all of the  following conditions are
met:  (1) the net increase of all pollutants regulated  under the Act
after application of BACT would be less than 50 tons/year,  (2) no  pollutant
would be causing or contributing to a violation of the  standards (NAAQS),
and (3) source must have been in existence on  March 1,  1978.
                                   A-20

-------
     The results of the impact analysis as  described  in  this box will be
used for subsequent portions of the ambient air  quality  analysis.

Box 22.  Is the existing air quality <  Table A-2?

     The proposed source or modification must determine  the existing air
quality concentration in the area of impact of the  proposed source or
modification before construction for each applicable  pollutant.  Modeling
by itself or in conjunction with monitoring data would be  used  for this
determination.   Application of these models must be consistent  with
reference 15.

     If the proposed source or modification is remote and  not affected
by other readily identified man-made sources,  two options  for determining
existing air quality concentrations from existing data are available.
The first option is to use air quality  data collected in the vicinity of
the proposed source or modification, the second  option is  to use average
measured concentrations from a "regional" site to establish a background
concentration.   Additional guidance on  determining  the background air
quality concentrations may be found in  reference 15.  See  also  the
discussion or use of representative air quality  data  in  Section 2.4 of
this guideline.

     If the existing air quality is less than  the values in Table A-2,
proceed to box 24; if not, proceed to box 23.

Box 23.  Are the air quality impacts <  Table A-2?

     The projected impact of the proposed source or modification was
previously determined by the screening  procedure or refined model esti-
mates.   These modeled concentrations are compared to  the significant
monitoring concentrations shown in Table A-2.  If these modeled concen-
trations are less than the values in Table  A-2,  proceed to box  24; if
not, proceed to box 25.

Box 24.  Is there an apparent threat to PSD increments or  NAAQS, or is
         there  a potential adverse impact on a Class  I area?

     An apparent threat to a PSD increment  is  consumption  by the proposed
source or modification of 90 percent or more of  the remaining allowable
increment.  An  apparent threat to the NAAQS is when the projected air
quality after construction is equal  to  or greater than 90  percent of the
NAAQS.   Potential adverse impacts on a  Class I area must be determined
on a case-by-case basis by the permit granting authority.

     Therefore, if there is an apparent threat to PSD increments or
NAAQS, or if there is a potential adverse impact on a Class I area,
proceed to box 29; if not, proceed to box 28.

Box 25.  Are proposed emissions a criteria  pollutant  or VOC?

     Determine if the pollutant is a criteria  pollutant  (TSP, PMio, S02,
CO, N02 or Pb)  or VOC.  If the pollutant is a  criteria pollutant or
VOC, proceed to box 27; if not, proceed to  box 26.
                                   A-21

-------
Box 26.  Is there an approved monitoring technique  available?

     Acceptable measurement methods currently  exist for  some noncriteria
pollutants, while other methods are currently  under review and  have not
been designated as an acceptable measurement method.   Section 2.6 of
this guideline discussed the designation of acceptable measurement
methods for noncriteria pollutants.   If  an  acceptable measurement method
does exist, proceed to box 29;  if not, proceed to box 28.

Box 27.  Reconstruction monitoring data required.

     Reconstruction air qua! ity monitoring data are required for this
part of the ambient air quality analysis.   The proposed  source or modifica-
tion has the option of using representative air quality  data or monitoring.
Considerations and constraints  on the use of existing data were discussed
in Section 2.4 of this guideline.  It should be noted  that a dispersion
model may be used in verifying  the representativeness of the data.  If a
proposed source or modification chooses  to  monitor  instead of using
representative air quality data, then the specifics to be followed on
network design, probe siting, quality assurance, number  of monitors,
etc., were previously discussed in this  guideline.

     The monitoring data required in this box  will  be  used in Parts 5,
6 and 7 of the PSD permit application.

Box 28.  No preconstruction monitoring data required.

     If there is no approved monitoring  technique for the noncriteria
pollutants, or if there is no apparent threat  to PSD increments or
NAAQS, or if there is no potentially adverse impact on a Class  I area,
then generally no preconstruction monitoring data will be required.
However, proceed to the Part 5-Source Impact Analysis  for remaining
analyses.

Box 29.  Preconstruction monitoring data may be required.

     The permit granting authority must  determine on a case-by-case
basis if monitoring data will  be required when there is  an apparent
threat to PSD increments or NAAQS, or when  there is a  potential  adverse
impact on a Class I area.  Special attention must be given to Class I
areas where the proposed source or modification would  pose a threat to
the remaining allowable increment.  For  those  situations where the air
quality concentration before construction is near the concentrations
shown in Table A-2 and there are uncertainties associated with this air
quality determination then preconstruction  air quality monitoring data
may be required.  Some situations where  noncriteria monitoring may be
required were discussed in Section 2.1.3 of this guideline.

     Regardless of the monitoring data decision, proceed on to the Part
5-Source Impact Analysis for remaining analyses.
                                   A-22

-------
                                REFERENCES

 1.  Federal Register 43:26380-26410.   June 19,  1978.

 2.  Ambient Monitoring Guidelines for Prevention  of Significant  Deteri-
     oration (PSD).   U.S.  Environmental  Protection Agency,  Research
     Triangle Park,  NC.  OAQPS No. 1.2-096.  May 1978.

 3.  Federal Register 44:51924-51959.   September 5,  1979.

 4.  United States Court of Appeals,  No. 78-1006,  Alabama Power Company,
     et. al., Petitioners v. Douglas  M.  Costle,  as Administrator, Environ-
     mental Protection Agency, et. al.,  Respondents.  Decided  December  14,
     __
 5.  Federal Register 45:52676-52748.   August 7,  1980.

 6.  Federal Register 49:10408-10462.   March  20,  1984.

 7.  Federal Register (date of proposal)  1984.

 8.  Federal Register 44:27558-27604.   May  10,  1979."

 9.  Pace, T.G. and N. H.  Frank,  Procedures for Estimating  Probability of
     Nonattai nment of a PM^o NAAQS  Using  Total  Suspended  Particulate or
     Inhal able Particul ate Data.   U.S.  Environmental  Protection  Agency,
     Research Triangle Park, NC.   December  1982 (DRAFT).

10.  Ludwig, F.L., J.H. Kealoha,  and E.  Shelar.  Selecting  Sites for
     Monitoring Total Suspended Particulates.   Stanford Research Institute,
     Menlo Park, CA.   Prepared for U.S.  Environmental  Protection Agency,
     Research Triangle Park, NC.   EPA  Publication No.  EPA-450/3 -77-018.
     June 1977, Revised December 1977.

11.  Ball, R.J. and G.E.  Anderson.   Optimum Site  Exposure Criteria  for
     S02 Monitoring.   The  Center  for the  Environment  and  Man,  Inc.,
     Hartford, CT.  Prepared for  U.S.  Environmental Protection Agency,
     Research Triangle Park, NC.   EPA  Publication No.  EPA -450/3 -77-013.
     April 1977.

12.  Ludwig, F.L. and J.H. S. Kealoha.   Selecting  Sites  for  Carbon Monoxide
     Monitoring.  Stanford Research Institute,  Menlo  Park,  CA.   Prepared
     for U.S. Environmental Protection  Agency,  Research Triangle Park, NC.
     EPA Publication  No.  EPA -450/3 -75-077.   September 1975.

13.  Ludwig, F.L. and E.  Shelar.   Site  Selection  for  the  Monitoring of
     Photochemical Air Pollutants.   Stanford  Research Institute, Menlo Park,
     CA.  Prepared for U.S. Environmental Protection  Agency,  Research
     Triangle Park, NC.  EPA Publication  No.  EPA -450/3 -78-013.   April 1978.

14.  Pel ton, D.J. and R.C. Koch.   Optimum Sampling Site Exposure Criteria
     for Lead.  GEOMET Technologies, Inc.,  Rockville,  MD.   Prepared for
     U.S. Environmental Protection  Agency,  Research Triangle  Park,  NC.
     EPA Publication  No.  EPA-450/4-84-012.   February  1984.
                                      ff-23

-------
15.  Guideline on Air Quality Models.  OAQPS,  U.S.  Environmental  Protection
     Agency, Research Triangle Park, NC.   EPA  Publication No.  EPA-450/2-
     78-027 (NTIS PB 288-783).  April 1978.

16.  Bryan, R.J., R.J.  Gordon, and H. Menck.  Comparison of High  Volume
     Air Filter Samples at Varying Distances from Los Angeles  Freeway.
     University of Southern California, School  of Medicine, Los Angeles,
     CA.  (Presented at 66th Annual  Meeting  of Air  Pollution Control
     Association, Chicago, IL., June 24-28,  1973. APCA 73-158.)

17.  Teer,  E.H.  Atmospheric Lead Concentration Above an Urban Street.
     Master of Science Thesis, Washington University, St. Louis,  MO.
     January 1971.

18.  Bradway, R.M., F.A. Record, and W.E. Bel anger.  Monitoring and Modeling
     of Resuspended Roadway Dust Near Urban  Arterials.   GCA Technology
     Division, Bedford, MA.  (Presented at 1978 Annual  Meeting of Transporta-
     tion Research Board,  Washington, D.C.   January 1978.)

19.  Pace,  T.G., W.P. Freas, and E.M. Afify.  Quantification of Relationship
     Between Monitor Height and Measured  Particulate Levels in Seven  U.S.
     Urban  Areas.  U.S. Environmental Protection Agency, Research Triangle
     Park,  NC.  (Presented at 70th Annual Meeting of Air Pollution Control
     Association, Toronto, Canada, June 20-24,  1977.   APCA  77-13.4.)

20.  Harrison, P.R. Considerations for Siting  Air Quality Monitors in
     Urban  Areas.  City of Chicago, Department of Environmental Control,
     Chicago, IL.  (Presented at 66th Annual Meeting of Air Pollution
     Control Association,  Chicago, IL., June 24-28, 1973.  APCA 73-161.)

21.  Study  of Suspended Particulate Measurements at Varying Heights Above
     Ground.  Texas State  Department of Health, Air Control  Section,
     Austin, TX.  1970. p. 7.

22.  Rodes, C.E. and G.F.  Evans.  Summary of LACS Integrated Pollutant
     Data.   In:  Los Angeles Catalyst Study  Symposium.   U.S.  Environmental
     Protection Agency, Research Triangle Park, NC.  EPA Publication  No.
     EPA-600/4-7 7-034.   June 1977.

23.  Lynn,  D.A. et. al. National Assessment of the Urban Particulate
     Problem:  Volume 1, National Assessment.   GCA  Technology  Division,
     Bedford, MA.  U.S. Environmental Protection Agency, Research Triangle
     Park,  NC.  EPA Publication No. EPA-450/3-75-024.  June 1976.

24.  Pace,  T.G.  Impact of Vehicle-Related Particulates on  TSP Concentrations
     and Rationale for Siting Hi-Vols in  the Vicinity of Roadways. OAQPS,
     U.S. Environmental Protection Agency,  Research Triangle Park,  NC.
     April  1978.

25.  Air Quality Criteria  for Lead.  Office  of Research and Development,
     U.S. Environmental Protection Agency, Washington,  DC.   EPA-600/8-77-017.
     December 1977.

26.  Lyman, D.R.  The Atmospheric Diffusion  of Carbon Monoxide and Lead
     from an Expressway.  Ph.D. Dissertation,  University of Cincinnati,  OH.
     1972.
                                     A-24

-------
27.  Burton, R.M. and J.C. Suggs.  Distribution of Particulate Matter
     from the Roadway of a Philadelphia Site.   Environmental  Monitoring
     Systems Laboratory, U.S. Environmental  Protection Agency, Research
     Triangle Park, NC.  September 1983 (Draft).

28.  Koch, R.C. and H.E. Record.  Network Design and Optimum  Site Exposure
     Criteria for Particulate Matter,  GEOMET Technologies,  Inc.,  Rockville,
     MD.  Prepared for U.S. Environmental Protection Agency,  Research
     Triangle Park, NC.  EPA Contract  No. 68-02-3584.   March  1983.

29.  Wechter, S.G.  Preparation of Stable Pollutant Gas Standards Using
     Treated Aluminum Cylinders. ASTM  STP.   598:40-54, 1976.

30.  Wohlers, H.C., H. Newstein and D.  Daunis.  Carbon Monoxide and  Sulfur
     Dioxide Adsorption On and Description From Glass, Plastic and Metal
     Tubings.  J. Air Poll. Con. Assoc. 17:753, 1976.

31.  Elfers, L.A.  Field Operating Guide for Automated Air  Monitoring
     Equipment.  U.S. NTIS.  p. 202,  249, 1971.

32.  Hughes, E.E.  Development of Standard Reference Material  for Air
     Quality Measurement.  ISA Transactions, 14:281-291,  1975.

33.  Altshuller, A.D. and A.G. Wartburg.  The  Interaction of  Ozone with
     Plastic and Metallic Materials in a Dynamic  Flow System.   Intern.
     Jour. Air and Water Poll., 4:70-78, 1961.

34.  CFR Title 40 Part 53.22, July 1976.

35.  Butcher, S.S. and R.E. Ruff.  Effect of Inlet Residence  Time on
     Analysis of Atmospheric Nitrogen  Oxides and Ozone.  43:1890, 1971.

36.  Slowik, A.A. and E.B. Sansone.   Diffusion Losses  of  Sulfur Dioxide
     in Sampling Manifolds.  J. Air Poll. Con. Assoc., 24:245, 1974.

37.  Yamada, V.M. and J.R. Charlson.   Proper Sizing of the  Sampling  Inlet
     Line for a Continuous Air Monitoring Station.  Environ.  Sci. and
     Technol., 3:483, 1969.

38.  Quality Assurance Handbook for Air Pollution Measurement Systems;
     Volume I - Principles.  U.S. Environmental Protection  Agency (MD-77)
     Research Triangle Park, NC.  EPA  Publication No.  EPA-600/9-76-005.
     March 1976.

39.  Quality Assurance Handbook for Air Pollution Measurement Systems;
     Volume II - Ambient Air Specific  Methods.  U.S.  Environmental Protec-
     tion Agency (MD-77), Research Triangle  Park, NC.   EPA  Publication No.
     EPA-600/4-77-027a.  May 1977.

40.  Traceability Protocol for Establishing  True  Concentrations of Gases
     Used for Calibration and Audits of Air  Pollution  Analyzers,  U.S.
     Environmental Protection Agency (MD-77),  Research Triangle Park, NC.
     Protocol No. 2.   June 1978.
                                 A-25

-------
41.  Transfer Standards for Calibration of Ambient Air Monitoring Analyzers
     for Ozone.  U.S. Environmental  Protection Agency, Department E (MD-77),
     Research Triangle Park, NC.  EPA Publication No. EPA-600/4-79-056.
     September 1979.

42.  Cole, H.S.  Guidance for National  Air Quality Trend Stations (NAQTS):
     Review of Meteorological  Data Sources.   OAQPS,  U.S.  Environmental
     Protection Agency, Research Triangle Park, NC.   January 1978 (Draft).

43.  On-Site Meteorological  Instrumentation  Requirements  to Characterize
     Diffusion from Point Sources.  U.S. Environmental Protection Agency,
     Research Triangle Park, NC.  EPA-600/9-81-020 (NTIS No. PB 81-247-223).
     April 1981.

44.  Guideline for Determination of Good Engineering Practice Stack
     Height (Technical  Support Document for  the Stack Height Regulations).
     U.S. Environmental Protection Agency, Research  Triangle Park, NC.
     EPA-450/4-80-023.  (NTIS No. PB82-145-301).  July 1981.

45.  Gill, G.C.,  I.E. Olsson,  J. Sela,  and M. Suda.   Accuracy of Wind
     Measurements on Towers or Stacks.   Bull. Amer.  Meteorol. Soc.
     48:665-674,  September 1967.

46.  Turner, D.B.  Workbook of Atmospheric Dispersion Estimates, Revised.
     Office of Air Programs, U.S.  Department of Health,  Education and
     Welfare, Research Triangle Park, NC.  Publication No.  AP-26.  1970.

47.  Onsite Meteorological  Programs.   Nuclear Regulatory  Commission,
     Washington,  D.C.  NRC Guide 1.23  February 1972.

48.  Weber, A.H.   Atmospheric  Dispersion Parameters  in Gaussian Plume
     Modeling - Part 1:  Review of Current Systems and Possible Future
     Developments.   U.S.  Environmental  Protection Agency,  Research Triangle
     Park, NC.  EPA Publication No.  EPA-600/4-76-030a.  July 1976.

49.  Holzworth, G.C.  Mixing Heights, Wind Speeds, and Potential  for
     Urban Air Pollution  Throughout  the Contiguous United States.  Office
     of Air Programs, U.S.  Department of Health,  Education  and Welfare,
     Research Triangle Park, NC.  Publication No. AP-101.   1972.

50.  Protecting Visibility:   An EPA  Report to Congress.   U.S.  Environmental
     Protection Agency, Research Triangle Park, NC.   EPA  Publication  No.
     EPA-450/5-79-008.   October 1979.

51.  Interim Guidance for Visibility  Monitoring.    U.S.  Environmental
     Protection Agency, Research Triangle Park, NC.  EPA-450/2-80-082
     (NTIS No. PB81-157-760).   November 1980.

52.  Workbook for Estimating Visibility Impairment.   U.S.  Environmental
     Protection Agency, Research Triangle Park, NC.   EPA-450/4-80-031
     (NTIS No. PB81-157-885).   November 1980.
                                 A-26

-------
53.  Guidelines for Siting and Exposure of Meteorological  Instruments
     for Environmental  Purposes.   Meteorology and Assessment Division,
     U.S. Environmental Protection Agency, Research Triangle Park,  NC.
   .  January 1976 (Draft).

54.  Hoehne, W.E.  Progress and Results of Functional  Testing.   National
     Oceanic and Atmospheric Administration,  Sterling,  YA.   NOAA Tech-
     nical Memorandum NWS T&EL-15.  April  1977.

55.  Stone, R. J. National  Weather Service Automated Observational
     Networks and the Test and Evaluation  Division Functional  Testing
     Program.  In:   Preprint Volume for Fourth Symposium on Meteorological
     Observations and Instrumentation, Denver, CO.  April  10-14, 1978.

56.  Mazzarella, D.M.  Meteorological  Sensors in Air Pollution  Problems.
     In:  Proceedings of the Second Joint  Conference on Sensing of
     Environmental  Pollutants.   Instrument Society of America,  Pittsburgh,
     PA.  1973.

57.  Mazzarella, D.M.  Meteorological  Instruments for Use  Near  the  Ground -
     Their Selection and Use in Air Pollution Studies.   Science Associates,
     Inc., Princeton, NJ.  (Presented  at Conference on  Air Quality  Meteo-
     rology and Atmospheric Ozone, Boulder, CO., 1977.)

58.  Johnson, W.B.  and R.E. Ruff.  Observational Systems and Techniques  in
     Air Pollution  Meteorology.  In:   Lectures on Air Pollution and
     Environmental  Impact Analyses. American Meteorological  Society,
     Boston, MA.   1975.

59.  George. D.H. and K.F.  Zeller.  Visibility Sensors  in  Your  Air  Quality
     Program.  In:   Proceedings of the Second Joint Conference  on Sensing
     of Environmental Pollutants.  Instrument Society of America, Pittsburgh,
     PA.  1973.
                               .. — %
60.  Quality Assurance Handbook for Air Pollution Measurement Systems:
     Volume IV.  Meteorological Measurements.   U.S.  Environmental Protection
     Agency (MD-77), Research Triangle Park,  NC.  EPA Publication No. EPA-
     600/4-82-060.   February 1983.

61.  American Society for Testing Materials.   Standard  for Metric Practice,
     E-380-76. .ASTM, 1916 Race Street,  Philadelphia,  PA  19103.  1976.

62.  Budney, L.J.,  Guidelines for Air  Quality Maintenance  Planning  and
     Analysis Volume 10 (Revised):  Procedures for Evaluating Air Quality
     Impact of New Stationary Sources.  U.S.  Environmental  Protection
     Agency, Research Triangle Park, NC.   OAQPS  No.  1.2-029R, EPA
     Publication No. EPA-450/4-77-001.  October 1977.
                                      A-27

-------