DRAFT
                   PROCEDURES
                       FOR
         CONDUCTING AIR PATHWAY ANALYSES
                       FOR
             SUPERFUND APPLICATIONS

                    VOLUME IV

       Procedures for Dispersion Modeling
                       and
                 Air Monitoring
                       for
                    Superfund
              A1r Pathway Analysis

                       by

                 NUS CORPORATION
                910 Clopper Road
          Galthersburg. Maryland  20877

             Contract No. 68-01-7310
             Work Assignment No. 62
  Mr. Nark E. Garrison. Work Assignment Manager

U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION III
              841 CHESTNUT BUILDING
             PHILADELPHIA. PA  19107

                  DECEMBER 1988
                                                                    "I
                                                                      §

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                                                        DRAFT
                   PROCEDURES
                       FOR
         CONDUCTING AIR PATHWAY ANALYSES
                       FOR
             SUPERFUND APPLICATIONS

                   VOLUME IV

       Procedures for Dispersion Modeling
                       and
                 Air Monitoring
                       for
                   Super-fund
              A1r Pathway Analysis

                       by

                 NUS  CORPORATION
                910 Clopper Road
          Galthersburg, Maryland   20877

             Contract No.  68-01-7310
             Work Assignment No. 62
  Mr. Mark E. Garrison. Work Assignment Manager

U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION III
              841 CHESTNUT BUILDING
             PHILADELPHIA, PA  19107

                  DECEMBER 1988

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                                DISCLAIMER

     This  document was  prepared  for the  U.S.  Environmental Protection
Agency by  NUS Corporation, Galthersburg,  Maryland,* under Contract No. 68-
01-7310, Work Assignment No. 62.   The contents  are reproduced herein as
received from  the contractor.   The  opinions, findings,  and  conclusions
expressed  are those  of  the authors and not  necessarily those of the  U.S.
Environmental Protection Agency.
                                     11

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                                  CONTENTS

Figures   .................... 1v
Tables    .................... J
Acknowledgment  .................. 1x

     1         Introduction ..............    1-1

     2         Atmospheric Dispersion Modeling Procedure  ....    2-1

                    Overview   .............    2-1

                    Step 1 - Collect and review Input Information  .    2-11
                    Step 2 - Select  modeling sophistication level  .    2-27
                    Step 3 - Develop modeling plan  ......    2-41
                    Step 4 - Conduct modeling ........    2-64
                    Step 5 - Summarize and evaluate results  .  .  .    2-72
                    Example application ..........    2-89

     3         A1r Concentration Monitoring Procedure  .....    3-1

                    Overview   .............    3-1

                    Step 1 - Collect and review Input Information  .    3-6
                    Step 2 - Select  monitoring sophistication level.    3-17
                    Step 3 - Develop monitoring plan   .....    3-31
                    Step 4 - Conduct monitoring  .......    3-96
                    Step 5 - Summarize and evaluate results  .   .  .    3-107
                    Example application ..........    3-124
     4         References   ..............     ~

Appendix A     Bibliography of A1r Monitoring Standard Operating
               Procedures   ..............    A~l

Appendix B     Excerpt from Technical Assistance Document  .  .  *   .    B-l

Appendix C     Background Information   ..........    C-l
                                      111

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                                   FIGURES

Number
1-1       Relationship of Volume IV to Volumes I-III ....     1-3
1-2       Superfund air pathway analyses technical  procedures -
          general  format  	     1-5
2-1       Superfund air pathway analyses dispersion modeling
          protocol	     2-9
2-2       Step 1 - Collect and review Input Information .  .  .     2-12
2-3       Step 2 - Select modeling sophistication 	     2-28
2-4       Selection of screening versus refined dispersion
          modeling	     2-30
2-5       Evaluation of hazard Index and APA uncertainty
          factors	     2-32
2-6       Select modeling constituents  .  	     2-46
2-7       Representation of an Irregularly shaped area source
          by 11 square area sources	     2-54
2-8       Example of nested subdivision of area source .   .    .     2-55
2-9       Step 4 - Conduct modeling	     2-66
2-10      The dispersion modeling process  	     2-68
2-11      Step 5 - Summarize and evaluate results   ...     .     2-73
2-12      Example of a computer generated ground level
          Isopleth plot	     2-75
2-13      Example atmospheric dispersion (dilution) pattern.   .     2-77
2-14      Drainage flow smoke test results  	     2-86
2-15      Drainage flow Impact area and dilution factors   .  .  .     2-87
2-16      Example site plan for air dispersion modeling   .   .  .     2-90
2-17      Receptor grid close to the  site	     2-96
3-1       Superfund air pathway analyses air  monitoring
          protocol	      3-4
3-2       Step  1  - Collect and review Input Information  ...      3-7
                                      1v

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FIGURES (Continued)
Number
3-3
3-4

3-5

3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18

Step 2 - Select monitoring sophistication level . . .
Selection of screening versus refined air

Evaluation of hazard Index and APA uncertainty





Specify meteorological monitoring program 	






Superfund air monitoring QA/QC strategy 	




Example of downwind exposures at air monitoring
Example application of downwind frequency analyses . .
Example atmospheric dispersion (dilution) pattern . .
Example site plan and air monitoring network ....
Pace
3-18
3 10
-22
3M M
-24
3-32
3-35
3-41
3-49
3-90
3-97
3-104
3-108
3-116
3-119
3-121
3-123
3-125

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                                   TABLES
Number
                                                                        Page
2-1         Summary of  dispersion modeling recommendations and
            objectives	   2-3

2-2         Sources associated with Superfund activities and their
            characteristics   	   2-6

2-3         Example - Superfund Air Dispersion Modeling Input
            Information Form	2-15

2-4         Example of  Input requirements for various source
            categories	2-19

2-5         Summary of  Input meteorological data for jse 1n
            dispersion  modeling for Superfund APAs     	  2-24

2-6         A summary of dispersion modeling techniques for
            Superfund APAs	2-36

2-7         A summary of dispersion modeling refined techniques
            for Superfund APAs	2-39

2-8         An outline for the dispersion modeling plan for a
            Superfund APA    	2-4Z

2-9         Classification of organic and  Inorganic compounds for
            ambient air modeling studies   	  2-47

2-10        Suggested meteorological data  screening criteria     .  .  .  2-70

2-11        Example criteria for Identifying the geographic area of
            applicability for dispersion modeling results  relevant
            to receptors of  Interest	2-80

2-12        Example format for evaluation  of hazard Index  values for.  2-82
            toxicants  and carcinogens at receptor locations
            associated with  the maximum concentrations

2-13        Example format for evaluation  of hazard Index  values
            relevant to ARARs at  locations associated  with maximum
            concentrations   	   2-85

2-14        Target constituents modeled for each of the  sources at
            the  site	2-93

 3-1        Summary of air Monitoring applications   	    3-2

 3-2        Example -  Superfund  A1r Monitoring Program Input
             Information Form	3~10
                                      v1

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                             TABLES  (Continued)

Title
3-3         Summary of technical  air  monitoring objectives  	  3-19
3.4         An overview of screening  air monitoring/sampling
            techniques	3-27
3-5         An overview of refined air monitoring/sampling
            techniques    	3-30
3-6         Classification of organic and Inorganic compounds for
            ambient air monitoring studies  	  3-36
3-7         Recommended system accuracies and resolutions 	 3-44
3-8         Recommended response characteristics for meteorological
            sensors
                                                                        3-45
3-9         Factors and associated elements that affect the design of
            air monitoring programs for Superfund APAs   	   3-47
3-10        A1r monitoring station number and location recommendations
3-11        A summary of key probe siting criteria for air monitoring
            stations
                                                                        3-55
3-12        Program duration and frequency of monitoring as a function
            of the Superfund project step    	3-59
3-13        Summary of air monitoring method recommendations   ....   3-61
3-14        Summary of screening techniques for detection of organic and
            Inorganic compounds 1n ambient air	-..  .  .   3-69
3-15        A summary of refined sampling and analysis techniques for
            organlcs and Inorganics 1n air   	  .....   3-72
3-16        Summary of sampling and analytical methods for refined
            monitoring for organic and Inorganic compounds 1n ambient
            air - volatile aromatlcs   	   3-74
3-17        Summary of sampling and analytical methods for refined
            monitoring for organic and Inorganic compounds 1n ambient
            air - volatile halogenated hydrocarbons    	3-78
3-18        Summary of sampling and analytical methods for refined
            monitoring for organic and Inorganic compounds 1n ambient
            air - volatile oxygenates    	   3-79

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                             TABLES  (Continued)


Title                                                                   £SS1

3-19        Summary of sampling and analytical  methods- for refined
            monitoring for organic and Inorganic compounds 1n ambient
            air - semivolatile  phenolIcs  	  3-80

3-20        Summary of sampling and analytical  methods for refined
            monitoring for organic and Inorganic compounds 1n
            ambient air - semivolatile base/neutral extracts  ....  3-81

3-21        Summary of sampling and analytical  methods for refined
            monitoring for organic and Inorganic compounds 1n
            ambient air - semivolatile pestlcldes/PCBs  	  3-82

3-22        Summary of sampling and analytical  methods for refined
            monitoring for organic and Inorganic compounds 1n
            ambient air - volatile Inorganics    	  3-83

3-23        Summary of sampling and analytical  methods for refined
            monitoring for organic and Inorganic compounds In
            ambient air - developing  technologies    	  3-84

3-24        Typical commercially available screening monitoring
            and analysis equipment for organ1cs and Inorganics 1n
            air    	3-85

3-25        Summary of refined  screening monitoring equipment for
            organic compounds 1n ambient air   	  3-88

3-26        Quality assurance (QA) activities to be specified In
            program plan   	    3-101

3-27        Calibration requirements  for sampling and analysis
            Instrumentation    	    3-105

3-28        Typical sampling/analysis frequencies for QC samples   .    3-106

3-29        Suggested meteorological  data screening criteria   .  .  .    3-110

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                              ACKNOWLEDGMENT

     This  document  was  prepared for  the  U.S.  Environmental  Protection
Agency  (EPA)  by NUS  Corporation.   The  project  was  managed by  Mr.  Mark
Garrison. National  Oceanic and Atmospheric Administration, who Is assigned
to the EPA, Region III.  The principal authors were Dr. Ami ram Roffman and
Mr. Ronald Stoner.   The authors would  like to thank  Mr.  J1m Vlckery and
Mr. Joseph LaFornara of the EPA  Office  of Emergency and Remedial Response
as well as Mr. Joseph Padgett, Mr. Stan Sleva, Mr. Joseph Tikvart, and Mr.
Jack Durham of  the  EPA Office of A1r Quality  Planning and Standards, and
Mr. Al ClmorelH of the EPA, Region III, for their guidance and direction.
The authors would also like to acknowledge Mr.  Robert Jubach,  Mr. Thomas
laccarino, Mr.  Henry  Flrstenberg,  Mr.  Jeffrey  Panek, and  Ms.  Elizabeth
Butler for their overall contribution to this document.

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                                SECTION  1

                               INTRODUCTION
     The multlvolume set of Procedures for Conducting A1r Pathway Analyses
for  Suoerfund  Applications has  been developed  In response  to Increased
concern  by  the  U.S.   Environmental  Protection   Agency  (EPA)  regarding
potential hazardous air  emissions  from Superfund  sites.   These emissions
can occur at hazardous spill locations and undisturbed Superfund sites, as
well  as during  site  cleanups.    Under  the  Comprehensive  Environmental
Response,  Compensation,  and  Liability   Act   (CERCLA)   and  the  recent
Superfund  Amendments   and   Reauthorlzatlon  Act   (SARA),   EPA  has  the
responsibility  for  assessment  and   cleanup  of   these   Superfund  sites.
Although there  have  been potential human  health  risks from  air emissions
at  these  sites,  comprehensive national guidance  did  not exist concerning
methods that could be  used  to determine the magnitude and  Impact of  these
emissions.    Therefore,  the  goal  of   these   Procedures  1s  to   provide
technical recommendations  for the  conduct of  air pathway  analyses (APAs)
that  meet  the  needs  of  the Superfund  process,  presenting  alternative
technical approaches for the conduct of APAs and  providing  recommendations
for  preferred or  default  approaches.   The Procedures are Intended  for use
by  EPA  Remedial  Project  Managers  (RPMs),  Enforcement  Project Managers
(EPMs), and air experts, as well as by EPA Superfund contractors.

     The  Procedures for  Conducting  A1r  Pathway Analyses for Superfund
Applications consists of four volumes:
                                    1-1

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     •     Volume  I -  Application of  Air  Pathway  Analyses for  Suoerfund
          Activities

     •     Volume  II -  Procedures for  Developing Baseline  Emissions  from
          Landfills and Lagoons

     •     Volume  III  - Procedures  for Estimating  A1r  Emissions  Impacts
          from Remedial Activities at  NPL  Sites

     •     Volume   IV   -   Procedures  for  Dispersion   Modeling   and   A1r
          Monitoring for Suoerfund A1r Pathway Analyses.

     Volume I  defines  the general  approach  for the conduct of  APAs and
references  appropriate   sections   within  Volumes   II-IV  for  detailed
technical procedures  regarding modeling and monitoring  techniques.  Volume
II provides procedures for developing baseline air emission estimates, and
Volume III  provides  procedures  for estimating air  emission  Impacts  from
remedial   actions.   Specifically,  Volumes  II-IV present  alternative and
preferred  or  default  modeling  techniques and monitoring  techniques for
Implementing   the   APA   approaches   selected   based   on   Volume    I
recommendations.    This Information will  be  primarily  of  Interest to EPA
air experts and Superfund contractors responsible for the conduct of  APAs.
However,   the  technical   procedures provided  1n  Volumes  II-IV  are not
specific  to Superfund  activities.   Therefore, Volumes  II-IV  will also  be
useful to state  air staff responsible for supporting hazardous waste site
cleanup.

     The  emphasis  of  Volume  IV  1s  on providing  technical procedures for
dispersion modeling and  air monitoring.   The relationship of Volume  IV  to
Volumes   I-III 1s  Illustrated  1n   Figure 1-1.   Volume  IV  provides the
procedures  for   Implementing  activity  and  source-specific   dispersion
model1ng/a1r  monitoring  recommendations provided 1n Volume I.   Volumes  II
and   III  also  cross-reference  Volume   IV   for  certain  air   emission
characterization   approaches  that   require   the  conduct  of   dispersion
modeling and/or  air monitoring.   In addition, Implementation of  Volume  IV
                                    1-2

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            APA RECOMMENDATIONS (VOLUME  0
 VOLUME II
  CEDURE8 FOR
DEVELOPING BASE-
  LINE AIR EMIS-
 SION ESTIMATES
                               i
 VOLUME  IV PRO-
  CEDURES FOR
DISPERSION MOD-
  EUNQ AND AIR
   MONITORING
                                               VOLUME III PRO-
 ESTIMATING AIR
EMISSION IMPACTS
 FROM REMEDIAL
     ACTIONS
               SECTION  2
              DISPERSION
               MODELING
              PROCEDURES
               SECTION 3
                   AIR
               MONITORING
              PROCEDURES
   Flgur* 1-1.  Relationship of Volume IV to VolUMOO Mil.

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procedures frequently  necessitates  source emission  rate Inputs based  on
application of Volumes II  and HI.

     Volume IV  presents  technical  procedures for  the following types  of
APAs:

     •    Dispersion modeling procedures
     •    A1r monitoring procedures

     Section  2  presents  procedures for  the application of  atmospheric
dispersion  modeling  as   a  methodology   to   assess   potential   exposures
associated with air  emissions from  a Superfund  site.  This  material  will
Include  criteria  as  well  as   recommendations  for  selecting  models,
obtaining required  Input  data,  and  Interpreting modeling results.   These
procedures address  technical Issues  that are  significant  for  Superfund
applications.   Therefore, the procedures presented In  Section  2  should  be
considered as supplemental to, but not replacements  for, the Guideline  On
Air Quality Models (U.S.  EPA, 1986).

     Section  3  presents   procedures  for  the  application  of  air
concentration monitoring  to characterize  downwind exposure conditions from
Superfund air emission sources.  These  procedures discuss  the  technical
challenges  Involved  In the design  and   Implementation  of  an  air  toxic
monitoring  program.   Again,   the  emphasis   has   been  on   providing
recommendations  specific  to the conduct  of Superfund APAs.   Therefore,
available standard  procedures  for  the conduct of  air  toxic  monitoring
programs are  Identified and summarized.   However,  the material has  also
been  adapted   and   supplemented  as  necessary  to  address   Superfund
applications.

     The technical procedures presented 1n Sections  2-4  are based on the
general format  Illustrated  1n Figure 1-2  and  discussed In Volume  I.  The
major elements of these procedures are as  follows:
                                   1-4

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                APA RECOMMENDATIONS
                       (Velum* I)

                 o   Aotrvfty-Speclflo
                     Reoommond'atlona
                 o   Souree-Speelflo
                     Reoommondatlona
                 e   Mo«elln0XMonnorlne
                     Reeommene'atlene
                             1
                   COLLECT AND REVIEW
                 APA INPUT INFORMATION
                 e   Environmental
                       SELECT APA
                 SOPHISTICATION

                 o   Screening
                 e   Refined
       EPA
    Teohnleal
    Oultfellnee
                                >A PLAN
                    Evaluate APA uaaortataty
                        CONDUCT APA

                    Quality Control
                            1
mguro 1-a. euporfund Air Pathway Analyaoa Technical Proootfuroa
          aanoral format.
                      1-5

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          Collect  and  review APA  Input Information
     •    Select APA sophistication  level
     •    Develop  APA  plan
          Conduct  APA
     •    Sunnarlze/evaluate results
     •    Evaluate need  for additional analyses.

     The  following  1s  a brief  discussion of  each  of these  procedural
steps.

     Step  1  -  Collect  and Review  Input  Information—This  Initial  step
addresses  the  process  of  collecting  and  compiling  existing Information
pertinent to previous  site-specific  APAs based on a literature survey.  It
Includes  obtaining  available   source,  receptor,  and  environmental  data.
Once the existing data  have been collected, compiled, and evaluated, data
gaps  carT be  defined  and  a  coherent  monitoring  plan  or  modeling  plan
developed based on the site-specific requirements.

     Step  2  -  Select APA Sophistication  Level—This step  Involves  the
selection  of  the APA sophistication  level  considering  screening versus
refined  monitoring and modeling   techniques.    This selection  process
depends on program objectives  as well as available resource  and technical
constraints.   Technical aspects that  should be  considered  Include  the
availability of appropriate monitoring and  modeling techniques.

     Step 3 -  Develop APA  Plan—This  step Involves  preparation  of.an APA
plan.   The APA should  Include  documentation of  the  selected  technical
approach  (e.g.,  nonrepresentatlve   Input data,  modeling  Inaccuracies  and
monitoring  limitations).   The  application  of Data  Quality Objectives
(DQOs) will be an Important aspect  In  the development of an  APA plan.  The
selected  approach  should   be  based  on  EPA  technical  guidelines,  as
available.   The APA  plan  also facilitates peer review of the technical
approach and a formal  process  for approval  of the APA by the RPM/EPM.  The
peer review process may Involve EPA  air  experts  or contractor support.
                                    1-6

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     Step 4 -  Conduct  APA—This step Involves  the Implementation of  the
APA  plan  developed during  Step 3.   The  emphasis during Step  4 1s  on
conducting the  APA  commensurate  with  appropriate QC  measures  and  OQO
criteria.   This  also  Involves  documentation   of' the APA  process  (to
facilitate the QC  process  and establish an  Information base that may be
useful for APAs at  other Superfund  sites).

     Step 5 - Summarize and Evaluate Results—This step Involves reviewing
data  and  evaluating  APA results for  validity.   Additional  components of
this  step  should  Include  (a)  data  processing;   (b)  preparation  of
statistical summaries;  (c)  comparison of upwind  and downwind concentration
results;  and  (d)  concentration mapping. 1f  possible.   Estimates  of  data
uncertainties  based  on  Instrument limitations  and  analytical  technique
Inaccuracies should  also  be obtained and  used  to  qualify air monitoring
results.    Results  can  be  compared  to  applicable  or  relevant  and
appropriate  (ARAR)  air  criteria  and other  Superfund health  and safety
criteria.  The results  of  Step 5  can also provide Input to the Superfund
risk assessment process.

     This approach ensures that a  common thought process and strategy are
used  to plan and conduct APAs for  Superfund application.  As demonstrated
1n  Sections  2-3,  this  general approach  has  been  adapted  for  each of the
technical procedures presented 1n Volume IV.
                                    1-7

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                                 SECTION 2.0

                  ATMOSPHERIC DISPERSION MODELING PROCEDURE
2.1       OVERVIEW

     Atmospheric dispersion modeling  Is an air  pathway analysis  (APA)  that
provides calculations of concentrations of air toxic contaminants at receptor
locations of Interest  based on Input emission rate  and meteorological data.
Atmospheric dispersion modeling for Superfund activities  1s an Integral  part
of the planning and  decision-making  process  as related to  the protection of
public health and the environment.  This  section  provides  procedures for the
selection and application  of  atmospheric dispersion modeling  approaches for
Superfund APAs.

     The  major  Superfund  APA  dispersion  modeling   applications  can  be
summarized as follows:

          Emission  APAs:   Dispersion  models  can  be  used  to  estimate
          concentrations at receptors  of  Interest using Input emission  rate
          data based on air emission modeling.   Dispersion models can also be
          used  to estimate concentrations at  receptors  of  Interest using
          Input emission rate  data based on emission  rate monitoring.

          Confirmatory air monitoring APAs:  Dispersion modeling can be  used
          to  assist  In  designing  an air  monitoring program  (I.e.,  to
          determine appropriate monitoring  locations and monitoring period)
          as well  as 1n Interpretat1ng  and extrapolating monitoring results.
                                     2-1

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     Atmospheric dispersion models can be used  for monitoring program design
applications to Identify  offsite  areas of high  concentration relative  to
actual  receptor locations.    High-concentration  areas  that correspond  to
actual receptors are priority locations for  air  Bon1tor1ng stations.

     Dispersion  models  can  also  be  used  to  provide  seasonal  dispersion
concentration  "patterns'  based   on  available  representative  historical
meteorological  data (either onslte or offsite).   Dispersion patterns based on
modeling results can  be used to evaluate  the representativeness  of  the air
monitoring  data collection  period.    Representativeness  Is determined  by
comparing the dispersion concentration patterns  for the air monitoring period
with historical seasonal dispersion concentration patterns.

     Frequently. 1t may not  be practical to place air monitoring stations at
actual offsite receptor locations of Interest.  However.  It will be necessary
to  characterize concentrations at  these locations to conduct  a  health and
environmental  assessment.    In  these cases,  dispersion  patterns based  on
modeling results can  be used to extrapolate  concentrations monitored at the
Superfund site to offsUe receptor locations.

     A  summary  of Superfund  APA  dispersion  modeling  recommendations  and
objectives 1s presented In Table 2-1.  These recommendations  are presented as
a function of  source  classification  and  Superfund activities.   Emission rate
Inputs  for dispersion  modeling  applications  should  be  based  on technical
procedures presented  1n Volumes  II  and  III.    Meteorological modeling Input
data   should   preferably  be  based  on  an  onslte  monitoring program.
(Recommendations  for  the  conduct of  an  onslte  meteorological  monitoring
program  are discussed  In Sections  2.2.   and  3.0 of  this  volume).   The
preferred  dispersion  model for Superfund APA applications Is the Industrial
Source Complex  (ISC) model.  This model can be used for estimating short-term
concentrations  (I.e., the  ISCST  version)  and  long-term concentrations  (I.e..
ISCLT  version)  for a variety  of  Superfund  sources.   Further discussions of
the dispersion model  selection for  Superfund APAs are Included 1n  Sections
2.3 and  2.4.    In  addition,  1t Is  recommended  that  an onslte capability be
developed  to provide  near real-time  concentration estimates associated with
nonroutlne air  releases.   A combination of monitoring/modeling  approaches 1s
                                     2-2

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                                                                  TABLE 2-1

                                        SUNHWY OF DISKRSION MODELING RECMCIIMTKMS MB OUCaiVES
 Source Classification
     Dispersion Modeling Objectives
             AM Recommendations
 Superfuntf Activities
Uncontrolled source
Provide sufficient data base on
concentrations of air toxic contaminants
for performing a detailed risk assessment
of public health and the environment for
onslte, perimeter and offslte receptors for
the baseline conditions (no-action
alternative).
Provide sufficient data base on
concentrations of air toxic contaminants
for performing a detailed risk assessment
of public health and the environment for
onslte. perimeter and offslte receptors for
the various remedial alternatives.
Provide Input to the design of air
monitoring program step.
Characterize baseline air concentration
   Obtain emission rate estimates based on
   procedures presented In Volumes II  and III.
   Obtain meteorological Input data based on
   an onslte monitoring program pursuant  to
   recommendations presented In Volume IV -
   Section 3.0.
   Conduct dispersion modeling based on
   considering ISC as the preferred model for
   Superfund APA applications.
RI/FS •
Screening/refined APA
Remediation source
Provide Input to the design of air
monitoring program for this step.
Provide air quality data to assess the
affects of the remedial action evaluated.
Characterize air concentration during
remedial/removal activities
-  Obtain emission rate estimates based on
   procedures presented In Volumes II and III.
-  Obtain meteorological Input data based on
   an onslte monitoring program pursuant  to
   recommendations presented In Volume IV -
   Section 3.0.
-  Conduct dispersion modeling based en
   considering ISC as the preferred model for
   Superfund APA applications.	
Remedial design (pilot
field studies)

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                                                                  TABLE 2-1
                                  SWMMV OF DISPERSION NDKLING REOMCHMTiaiS MB OBJECTIVES (Continued)
 Source Classification
     Dispersion Modeling Objectives
APA Recommendations
                                                 Superfund Activities
Renedlatlon source
Provide Input to the design of air
monitoring program for this step.
Provide data on calculated concentrations
of air toxic contaminants for routine and
non-routine releases In support of
protecting workers, the public and the
environment•
Provide data as a component of the
emergency repsonse system employed at the
site to be used together with Measured
concentrations*
Provide calculated concentration data In
support of protective actions during the
remedial action activities.
Characterize air concentrations during
remedial/removal activities
   Obtain emission rate estimates based on
   procedures presented In Volumes II  and HI.
   Obtain meteorological Input data based on
   an onslte Monitoring program pursuant to
   recommendations presented In Volume IV -
   Section 3.0.
   Conduct dispersion modeling based on
   considering ISC as the preferred model for
   Superfund APA-applications.
   Develop/Implement a site-specific APA
   emergency field guide based en a combined
   monitoring/modeling approach to obtain near
   realtime dispersion estimates (see  example
   1n Appendix C).
                                  Reaedlal actions
                                  (full-scale
                                  operations)
Controlled source
Provide air quality data base at the site
perlMeter and offslte as a part of
assessing the effectiveness of the renedltl
action iMpleMented.
Provide air quality data base at the site
perlMeter and offslte to demonstrate the
protection of public health and the
env1ronMent.
Confirm controlled source air concentrations
   Obtain emission rate estimates based on
   procedures presented In Volumes II and III.
   Obtain meteorological Input data based on
   an onslte monitoring program pursuant to
   recommendations presented In Volume IV -
   Section 3.0.
   Conduct dispersion modeling based on
   considering ISC as the preferred model for
   Superfund APA applications.	
                                  Operation and
                                  Maintenance
                                  (post-remedial
                                  activities)

-------
recommended to  provide this  capability.    An example  of this  approach 1s
provided 1n Appendix  C.

     The recommendations and objectives presented 1n Table  2-1  and  throughout
Section  2.0  have been   specified  based   on  consideration  of  Superfund
applications  (which   are  frequently  quite   different  from  typical  air
permitting/regulatory applIcatlons).

     Atmospheric dispersion modeling for Superfund activities  Includes a mix
of  sources  that.  In  general,  are  different  1n  configuration  and
characteristics from  the  sources  traditionally modeled  for air  permitting
applications.     The  traditional  sources  modeled  for  air  permitting
applications  are  usually  point  sources  (e.g.,  stacks)  emitting  combustion
products  such  as sulfur  dioxide,  nitrogen  oxides,  carbon  dioxide,   and
partIculate matter.

     In  contrast, the  Superfund  activities   Include  mainly  fugitive-area,
volume, and line  sources, and, to a small  extent,  point sources.  A  11st  of
the  types  of  sources  associated with  the various  Superfund activities  1s
presented 1n Table 2-2.  Superfund-area sources generally Include  landfills,
lagoons,  contaminated  soil   surfaces,  and  solidification/stabilization
operations.  Volume  sources Include  structures within processing facilities,
tanks,  and  containers.  Line  sources Include, In general, paved and  unpaved
roads,  and  point  sources  Include air strippers,  Incinerators,  and  1n  situ
venting  operations.   Most Superfund  sources  are considered  ground-level  or
near-ground-level, nonbuoyant releases.  In general,  traditional  sources are
considered elevated,  buoyant releases

     In  addition, compared  with  air emission from traditionally  modeled
sources.  Superfund  activity  emissions  exhibit more Involved  and  complex
processes that govern the rate and type of air emissions.  Air emissions from
Superfund activities could be continuous or Intermittent releases, or a one-
time release  over a  defined  period of time.   The releases can be  routine or
nonroutlne  due  to  an  unusual  event that could  occur  during   the  source
remediation.   Both gas and partlculate emissions could  be Involved.   The gas
emissions   Include  volatile  and   semlvolatlle  constituents,  and  .line
partlculate emissions  Include semlvolatlle, base neutrals, metals and other
                                     2-5

-------
PO
0»
                                                                        TABLE  t-f
                                           SOURCES ASSOCIATED WITH SUPERHMD ACTIVITIES MO THEIR OttRACTERISTICS
Superfund Source

• Landfills
• Lagoons
• Contaminated soil
• Containers
• Process
• Storage Tanks
Remediation sources
• Soil handling
• Air stripper*
• Incinerator*

Source
Configuration*

Fugitive area
fugitive area
fugitive area
fugitive area,
VOlUK
fugitive area.
voluw line, point
fugitive area

fugitive area
VOllflK
point, volime
point, voluw
Important Air Emission Mechanises
Gas Phase

volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization,
coabustlon
volatilization

volatilization
volatilization
conbuttlon
Partlculate Phase

Hind erosion,
•echanlcal disturbances
wind erosion.
•echanlcal disturbances
wind erosion.
•echanlcal disturbances
•echanlcal disturbances
wind erosion.
•echanlcal disturbances


Hind erosion.
•echanlcal disturbances
coabustlon
coabustlon
Cailsslon Node
Gas Phase


continuous
continuous




continuous.
Internment
continuous.
Intermittent
continuous.
Intermittent
i— ^— ^— — ^
Partlculate
Phase



Interalttent




Interalttent
continuous
continuous
Routine/
Nonroutlne
Release








routine/
nonroutlne
routine/
nonroutlne
routine/
nonroutlne
                 *Snal1  stacks where plwe Is  frequently In the dowmash cavity.

-------
                                                          TABLE 2-2
                      SOURCES ASSOCIATED UITN SUPERFUNO ACTIVITIES AMI THEIR CHARACTERISTICS (Continued)
Superfund Source
• In-sltu venting
• Solidification/
Stab llzatlon
Controlled sources
• Landfills
• Lagoons
• Soil surfaces
• Containers

Source
Configuration*
fugitive area
fugitive area.
volume

fugitive area
fugitive area
fugitive area
fugitive area.
volime
Important Air Emission NechanlSK
Gas Phase
volatilization
volatilization

volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
Partlculate Phase
--
Mind erosion.
mechanical disturbances

Mind erosion.
•echanlcal disturbances
Mind erosion.
•echanlcal disturbances
Mind erosion.
•echanlcal disturbances
•echanlcal disturbances
Emission Node
Gas Phase
continuous.
Internment
continuous.
Internment

continuous
continuous
continuous
continuous
Partlculate
Phase
-•
Internment

Intermittent
Intermittent
Intermittent
Intermittent
Routlne/Nonr
outlne
Release
routine/
nonroutlne
routine/
nonroutlne

routine
routine
routine
routine
•  most superfund sources are ground level or near ground level  nonbuoyant  releases

-------
Inorganic  constituents.    Table  2-1  lists  the  general   type  of  gas  and
participate emissions associated with  various Superfund activity  sources as
well as the anticipated  nature of the release.

     The factors  discussed  above clearly  Imply that  many of  the currently
employed air  dispersion  models for  traditional  sources, as  outlined  1n the
U.S.  Environmental  Protection  Agency's (EPA's)  Guidelines  on Air  Quality
Models (Revised) (EPA-450/2-78-027R. July 1986). have very  little  application
to the Superfund APA.  Only a limited  number of models 1n the EPA Guidelines
are applicable to the Superfund APA, as discussed 1n subsequent sections.  It
1s  therefore  Important  to define the  sources Involved, their configuration.
and their characteristics before a suitable model 1s selected.

      It  can also be  concluded that the added complexity  of air dispersion
modeling  for  Superfund  activities 1s mainly associated  with  estimating
emission rates  for the  specific source under consideration.  It 1s therefore
vital  to develop emission Inventory data  for the  sources Involved based on
the   procedures  outlined  1n  Volumes   II   and  III  of  this  Guideline  for
uncontrolled  sources, remediation  sources, and controlled  sources.   It  1s
also   critical  to  subdivide  large-area   sources  to  smaller   sources  1n
accordance  with the  guidelines provided  1n this  section to  provide for  a
reasonably  accurate  simulation  of  air releases,  transport, and  dispersion.
Although some  of  the emissions from  Superfund activities  Include  reactive
constituents, they are handled  1n this section as  passive  constituents.  This
 1s  a reasonable approximation because  the  source-receptor  distances  Involved
do  not  exceed   10  to  15 kilometers  and   the plume  travel time for  these
distances  ranges  from less than 1 hour to  1 or 2 hours.

      The various  technical factors  discussed above will  be further elaborated
 on  1n Sections  2.2 through 2.6.

      The procedures  for atmospheric  dispersion modeling  APAs presented  In
 this section are based  on a  five-step  process (Illustrated  1n Figure  2-1):

           Step  1  - Collect and review  Input Information
           Step  2 - Select modeling  sophistication  level
      •    Step  3 - Develop modeling plan
                                      2-8

-------
APA
 VOM. u A in
                                    ••view
                a  aaurea Data
                  Data ••«
                  Bfflrtramnaiital
                                        Data
                                                   Available.
                                                  Monitoring
                                                     Data
                         SELECT MODEL
                     CLASS AND  SOPHIS-
                        TICATION  LEVEL

                     e  Soroonlng
                     e  Roflnod
         EPA
       Modeling
      Quldollnoa
                      a aVaiwata
                                                EPA
                                             RovlowX
                                             Approval
                        aUMMAIUZBXBVALUATB
                      a Prapan
                        auMMartaa
                        Uneartalnty
l_
                                                   INPUT TO
                                                    OBCMION
          a-1.  aup«rfund Air Pathway An«ly«»« Olaparalon Medallng
               Protocol.
                              2-9

-------
     •    Step  4  - Conduct modeling
          Step  5  - Summarize and evaluate results

     Additional technical  discussion on dispersion  modeling 1s found  1n the
EPA's Guidelines  on  Air Quality Models.

     The following 1s  a brief  discussion of  each of  these steps.   An expanded
discussion 1s presented 1n the following subsections.

     Step  1 -  Collect  and  Review  Incut  Information—This  Initial  step
addresses  the  process of  collecting  and  compiling  existing  Information
pertinent to the air  dispersion  modeling  based on  a literature  survey.   It
Includes obtaining  available  source,  receptor,  and environmental  data (land
use classification,  demography, topography,  meteorology, and others).   Once
the existing data have been  collected, compiled, and evaluated, data gaps can
be defined and a coherent dispersion  modeling plan developed  based on site-
specific requirements.

     Step  2 -  Select Modeling  Sophistication  Level—This  step  Involves
selection  of  the  dispersion modeling   sophistication  level   considering
screening and refined modeling techniques.   This selection process depends on
program objectives  as  well  as available  resource and  technical  constraints.
Screening models generally  use  limited and  simplified  Input  Information to
produce a conservative estimate of exposure.   Use of a screening model allows
for an  Initial determination  of whether the Superfund site or site activity
will  present  an  air  pathway problem.    If  a  problem  Is detected  after
screening modeling  has been  performed, or a  determination 1s  already made
that  an  air pathway problem must be  addressed, the emission  sources should
then  be  evaluated with either a  more  sophisticated screening  technique or a
refined  model.   Technical  aspects that  should  be  considered  Include the
availability of  appropriate modeling   techniques  for  the Superfund  11st of
toxic constituents.   Modeling  approaches should be evaluated considering site
specific  factors,  Including  source configuration  and  characteristics,
applicability,   limitations,  performance   for  similar  applications,  and
comparison of advantages and disadvantages of alternative modeling methods.
                                    2-10

-------
     Step 3  - Develop  Modeling Plan—This  step Involves  preparation of  a
dispersion modeling  plan.    Elements  that  should  be addressed  1n  the  plan
Include  (a)  overview  of  the  Superfund  site  area,  (b)  selection  of
constituents  to  be modeled,  (c) modeling  methodology  (emission  Inventory.
meteorology,  receptor grid,  rural/urban classification,  models  to  be used,
concentration averaging time, and  special  situations such  as  wake effects).
and (d) documentation of the  air modeling plan.

     Step 4  - fondue! Modeling—This  step Involves the  actual activities of
conducting air  dispersion  modeling for  a Superfund  site.   It  Includes the
following: (a)  develop  emission Inventory,  (b)  preprocess and  verify model
Input data (emission Inventory, meteorology, receptor grid, and others), (c)
set  model  switches,  (d)  run  model  test  cases,   (e)  perform  dispersion
calculations, and (f) obtain  printout  of modeling Input  and output.

     Step 5  - Summarize and  Evaluate Results—This  step Involves reviewing
and assessing the dispersion modeling results.  Additional components  of this
step  should   Include  (a)  preparation  of data  summaries,  (b) concentration
mapping (Isopleths), (c) estimation of uncertainties, and (d) assessment.

2.2       STEP 1 - COLLECT  AND REVIEW  INPUT INFORMATION

2.2.1     Overview

     The  first  step In Implementing  an  air dispersion  modeling analysis  Is
the compilation  and  evaluation  of  available Information.   A summary  of this
process 1s presented 1n Figure 2-2.

     Careful  selection  of  Input for dispersion modeling  for a Superfund APA
1s critical  for  meaningful results.   Input data requirements  Include  source,
receptor, and environmental  data—specifically,  emission Inventories, source
characteristics,  meteorology,  and the   receptor   grid.     It  1s  therefore
paramount to collect  Input data that meet  the following basic objectives  of
dispersion modeling calculations:

          High accuracy of  data to the extent possible and practicable
          Sound methods and assumptions used to derive the Input data
                                     2-11

-------
    SOURCE DATA

e Slta Layout Map
e Source Specifications
e Contaminants List
o Toxlolty Faotora
o Offalto Soureoa
   RECEPTOR DATA

o Population Distribution
o Sensitive Raeaptora
o Slta Work Zonaa
o Local  Land Uaa
ENVIRONMENTAL DATA

o Olaparalon Data
o Climatology
o Topography
o Soil and  Vagatatlon
   PREVIOUS APA DATA

o Meteorologies!
  Monitoring Dsts
e •mission Hate ModellngX
  Monitoring
s Air Monitoring
s ARAM Summery
                        COLLECT
                       AVAILABLE
                      INFORMATION
                        COMPILE
                           AND
                        EVALUATE
                      INFORMATION
                       (TABLE 2-3)
                           INPUT
                            TO

                 STEP  2 - Salaet Monitoring
                    Sophistication  Laval

                            AND

                STEP  3 - Davalop Monitoring
                            Plan
   Figure 2-2. 8t«p 1 • Collect and Movlow Input Information.
                          2-12

-------
     The  following  Information,  at  a  minimum,  should  be  collected  and
reviewed to support  the air modeling program design:

          Source data
     •    Receptor data
     •    Environmental data

     This type of  Information serves a dual  purpose:

          It provides  an  overall  understanding of site-specific features that
          can affect dispersion modeling
          It provides  the necessary  Input to drive the dispersion model

     Most of  the  site-specific Information required for  Step  1 1s available
from  the  Superfund  Remedial  Project   Manager/Enforcement  Project   Manager
(RPM/EPM).   The quality  of available  Information will depend  on the  nature
and  extent  of  the  previously performed  studies.   For  example.  Information
available at  the  Initiation  of the Remedial  Investigation/Feasibility Study
(RI/FS)  may be limited  1n  nature.    However, Information available  for  the
Implementation  of remedial  actions  may  be very  thorough depending  on  the
level of effort and extent of the RI/FS.  In any event, available  Information
and data should be evaluated for  the following factors:

          Data quality objectives (DQO) for this study
          Technical  soundness of  methodologies employed
          Completeness and quality of the data
          Quality  assurance/quality  control   (QA/QC)  1n  support   of   the
          Information gathered
          Compatibility and applicability of the data
          Data  gaps

      Supplemental   Information  gathered  through  a   literature  search   1s
available from  records and documents from sources such as the following:

          National Weather Service
          U.S.  Environmental Protection Agency
                                     2-13

-------
     •     State and local agencies
     •     Contractor studies
     •     Other Federal government offices

     The Information collected  during  Step 1  should 'be  documented  using a
form similar  to the example presented In Table 2-3.  This  form should be used
to  Identify  and  evaluate  available  data.    In  addition,  copies of  data
summaries should be attached to the form to provide a convenient, complete
documentation package.

     The following subsections  provide  a  further discussion  of the various
types of data that should be collected during Step 1.

2.2.2     Source Data

     Site-specific Information  on the nature and extent of  the  contamination
1s critical for estimating the magnitude  of air emissions  from each of  the
sources and  1n  defining the  primary emission  constituents.   In addition.
Information on  source configuration  1s  vital.   As  discussed 1n Section  2.1
and summarized  1n  Table 2-1,  area sources constitute the  majority  of sources
1n a typical  Superfund  site.   In general,  the areas  Involved range  from small
(e.g.,  a fraction of an  acre) to large (tens of  acres),  and  their division by
source characteristics  and  size could  be critical  to  the  success  of this
modeling analysis.   The data should be available from the Superfund RPM/EPM.
Specific  Information that  should be  collected, evaluated,  and prepared  as
Input Into the dispersion model  Includes the following:

     •     Number and type of sources  at  the  site and their locations based on
          past   site  activities  and   Information   on  the  extent   of
          contamination.   (Example  sources  are   lagoons, drainage ditches,
          landfills, processing facilities,  Incinerators, air strippers,  and
          roads.)    The temporal  and spatial  variability  of  these sources
          should  also  be  addressed.    Source   variability  1s  an extremely
          Important  consideration  for  Superfund   APAs.    In  particular,
          emission/source  conditions  during   remediation   can   vary
          significantly.
                                    2-14

-------
                                         TABLE  2-3.   EXAMPLE  -  SUPERFUND AIR DISPERSION MODELING INPUT INFORMATION FORM
Data Type
Sour£e Da(a
• Site Layout Map
• Contaminants List
• Emission Inventory
• Contaminant Toxlclty
Factors
• Offslte Sources
Receptor Data
• Population Distribution
Nap
• Identification of
Sensitive Receptors
• Site Work Zones Map
• Local Land Use
Environmental Data
• Dispersion Data
- Hind Direction/Wind
Speed
Data Obtained
(Yes or No)









(Attachment
No.)









Evaluation Factors
Technical
Methods
Employed
Acceptable
(Yes or No)









Completeness
and Quality
of Data
Acceptable
(Yes or No)









QA/QC
Appropriate
(Yes or No)









Data
Relevant for
this
Application
(Yes or No)










Data Gaps
Significant
(Yes or No)









Comments





•



I
»-•
Ul

-------
                                    TABLE 2-3.  EXAMPLE - SUPERFUND AIR DISPERSION MODEL IKG INPUT INFORMATION FORM (Continued)
Data Type
Environmental Data (Cont'd)
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Haps
- Site
- Local Area
• Soil and Vegetation
Previous APA Data
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data Obtained
(Yes or No)








(Attachment
No.)








Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)








Completeness
and Quality
of Data
Acceptable
(Yes or No)








QA/QC
Appropriate
(Yes or No)








Data
Relevant for
this
Application
(Yes or No)








Data Gaps
Significant
(Yes or No)








Comments








O»

-------
Configuration and classification (based on Information presented 1n
Table 2-2 and site-specific considerations) of sources such as area
(e.g.. lagoons,  landfills), volume  (e.g.,  processing  facilities,
tanks),  line (e.g.,  roads, drainage  ditches),  and point  (e.g.,
Incinerator and air stripper stacks).

Dimensions of  each area,  volume,  and  line  source.  Including the
shape of sources  (e.g.,  1s the area source  a rectangle, triangle,
or  other shape,  does the  line source constitute  a  straight  or
curved line)  and  the portions  of  a line  source that do  not have
emissions.   Nonsquare-area sources have to  be approximated  by  a
square for use  1n the dispersion  model.   If the square  covers  a
large  area,   It  may  be  advisable  to  subdivide  1t Into  smaller
squares  1f  calculated  concentrations  are   required  at  short
distances  from  the  source.   Similarly  nonregular-volume  sources
have  to   be   approximated   by   a  cube  and  nonregu1ar-shaped-11ne
sources  have  to   be  approximated  by  minimizing   the  curvatures
Involved.

Stack  parameters,  Including   stack  height,  exit   diameter,  exit
velocity, and exit temperature  for  point sources.

Identification of constituents  associated  with  each source grouped
as  organic*  (volatile*,  semivolatlies, base  neutrals,  pesticides,
polychlorlnated blphenyls (PCBs), and  Inorganics (metals and other
toxic compounds (HgS,  HCN,  etc]).

Physical  and chemical  characteristics  of the constituents Involved,
Including  density relative to  air  (for gaseous-  emissions)  and
particle  size distribution  (for part1culate emissions).

Estimated typical  long-tern emission  rates and  typical  as  well as
maximum   short-term  emission  rates   for  each   source   under
consideration.  The emphasis  for Superfund  APAs 1s  to  define, as
practical, realistic  source  Input data  for  dispersion  modeling
purposes.    For  Superfund  APA  applications   the   uncertainties
associated with  the  Input  data as  well  as the  accuracy  of the
                          2-17

-------
         dispersion  model  are considered  during  the  data  Interpretation
         stage.   This  Is different from air quality  permitting applications
         for  traditional  sources,  which are generally based  on conservative
         source  emission  assumptions.    The  methods to  estimate  emission
         rates for  various undisturbed  and disturbed 'sources  at a Superfund
         site are  presented 1n  Volume  II  and  III. repectlvely.  of  this
         document.   These volumes provide guidance on methods and protocols
         for  estimating   the  emissions   from  various  types  of   sources
         utilizing  direct emission measurement techniques,  Indirect emission
         measurement  techniques,  air  monitoring  techniques, emissions
         predictive models,  and mass balance calculations.

     Table  2-4 represents an example of  Input requirements for various source
categories.   As  noted  1n  Section  2.1,  1n  contrast  to  conventional  air
emission sources  that  are  considered  mainly  as  point sources,  Superfund
sources consist mainly  of area, volume,  and line  sources.    Only  a limited
number  of   cases  Include point  sources,  mainly  during  remedial  cleanup
activities.  It  1s therefore Important to define the source configuration and
to  best approximate  Its  shape  to  the  shape  acceptable  by  the  employed
dispersion  model.

2.2.3    Receptor Data

     Receptor data  that  correspond   to  data  used  for  the  Superfund  risk
assessment  process  should  be Identified.   These data  will  provide the basis
for  specifying a  calculatlonal  (receptor) grid for Superfund APA dispersion
modeling application.

     Specific receptor  Information that  should  be collected and evaluated
before the selection of the receptor grid Includes the following:

     •    Population  distribution by  22.5-degree  sectors   1n  2-kilometer
          Increments for a distance of  10 kilometers  from the  site 1f "total
          risk"  1s to be considered

          Sensitive receptors within  10 kilometers of the site and  Individual
          residences and buildings within 1 kilometer of the site

                                    2-18

-------
                         TABLE 2-4
EXAMPLE OF INPUT REQUIREMENTS FOR VARIOUS SOURCE CATEGORIES
Input
Parameter
Source
location
Source
dimension
Source
emission rate
for each
constituent
under
consideration
Adjacent
obstructions
Initial
dilution
Particle mass-
size distri-
bution and
deposition
velocity
Source Category
Point
Coordinates of
the point (m)
Stack height
(m), exit
diameter (m),
exit velocity
(m/sec), exit
temperature
(OK)
Mass per unit
time
Height (m),
width (m),
length (m)

Line
Coordinates of
the center of
the line (m) .
Length (m),
width (m),
height (m)
Mass per unit
time per unit
length, or
mass per unit
time 1f
simulated by
an array of
Volume sources
"~
Initial
horizontal and
vertical
dimensions (m)
Area
Coordinates of
the southwest
corner of the
area
approximated
by a square
(m)
Width of the
square area
source (m)
Mass per unit
time per unit
area
— •
Initial
horizontal and
vertical
dimensions (m)
Volume
Coordinates of
the center of
the source (m)
Height of the
volume source,
(m), width (m)
Mass per unit
time
^—
Initial
horizontal and
vertical
dimensions (m)
Fraction of mass 1n each size group
Average deposition velocity for each mass size group (m/sec)
                            2-19

-------
          Site  work  zones  as  Identified  1n  the  Health  and  Safety Plan

     •    Local land  use  characterization  (e.g..  residential,  commercial)
          within 3 kilometers of the  site

     Sensitive  receptor  locations  Include  schools  and hospitals  associated
with  sensitive population segments,  as well  as  locations where  sensitive
environmental flora  and fauna exist,  Including  parks,  monuments, and forests.

2.2.4     Environmental Characteristics

     Information on  environmental  characteristics  pertinent to  a  Superfund
site  1s  a necessary component for defining air pathway  exposure potential.
In the case  of dispersion modeling,  the environmental  characteristics serve
as key  Input  to  the modeling calculations.   Environmental characteristics
that  should  be evaluated  and  assessed  prior  to the Implementation  of air
dispersion modeling  Include the following:

          Climate  (historical  summaries from  available  onslte  and  offslte
          sources)

               Annual and monthly or  seasonal wind roses

               Annual and monthly or seasonal  tabular summaries of mean wind
               speeds and atmospheric stability distributions

               Annual   and  monthly  or  seasonal   tabular  summaries  of
               temperature and  precipitation

      •    Meteorological survey results

               Hourly listing of all  meteorological  parameters for  the  entire
               monitoring period

               Daytime wind rose  (at  coastal or complex terrain sites)

               N1ght1me wind rose (at coastal or complex terrain sites)

                                     2-20

-------
     Sunnary wind rose for all  hours

     Summary of  dispersion  conditions  for  the Monitoring  period
     (joint frequency distributions  of  wind* direction  versus wind
     speed category and stability class  frequencies)

     Tabular summaries  of means  and  extremes for  temperature and
     other meteorological  parameters

Definition of soil conditions  (for landfills and contaminated soil
surfaces)

     Narrative of soil characteristics (e.g.. temperature, porosity
     and organic matter content)

     Characterization of  soil   contamination conditions  (e.g.,  1n
     waste piles and land  treatment units)

Definition of site-specific terrain and  nearby receptors

     Topographic map of the  area within  10  kilometers  of the site
     (U.S.  Geological  Survey   7.5-mlnute  quadrangle  sheets  are
     acceptable)

     Maps that  Indicate the  location of  the nearest residence for
     each of the  sixteen 22.5-degree  sectors  that  correspond to
     major  compass  points  (e.g..  north,  north-northwest),  the
     nearest  population  centers, and  sensitive  receptors  (e.g.,
     schools, hospitals and nursing homes)

Maps showing the topography  of the area,  the location of the units
of concern, and the location of meteorological monitoring equipment

A narrative description of the meteorological conditions  during the
air sampling periods, Including qualitative  descriptions  of weather
events and precipitation,  which are needed for data Interpretation
                           2-21

-------
          Sensitive  environmental  areas  (e.g..  wildlife  preserves,  parks,
          etc.)

     Like emission Inventory and source data, meteorological  data are another
key component of the basic data required  as an  Input Into  the  dispersion
model.  In searching for meteorological data, 1t Is Important to consider the
following factors:

          Meteorological  data drive  the  dispersion  model   and govern  the
          advectlon and  dispersion  of  contaminants  released  from  a source.
          It  1s   therefore  Important  to utilize  data  that  are  considered
          representative of the site area and vicinity.

     •    The length  of  record  for the  data base  should  be considered to
          avoid  a potential  bias 1n the dispersion  calculations.   A minimum
          of  1  year  of  data  are  required  to  run  most  refined dispersion
          models, with  5 years  being  preferred.   If  long-term  risk  1s the
          Issue   a  meterologlcal  data  period  longer  than   5 years  may be
          deslreable to characterize the expected exposure period.

     The  deployment of  an onslte meteorological program 1s recommended as a
part  of  the Superfund project planning phase.   Although data collected  from
an  onslte meteorological station may  not have  the  long record required for
their  direct use 1n  dispersion calculation, their  benefits  are  substantial
because

          They contain  site-specific data  that  could  be  used to assess the
          correlation with  offsite  meteorological  data  and  the  applicability
          of the  offslte  data to the site under  consideration.

          They  contain  site-specific  data  showing  the diurnal variation  of
          the  meteorological  parameters   affecting  plume  advectlon and
          dispersion.
                                     2-22

-------
          They  contain vital site-specific  Information  on topography-Induced
          flow.  Including drainage and valley  flows and the  effect  of water
          bodies on wind  flow.  Including  coastal  zone flow.

     Therefore.  1t 1s recommended that  an onslte  meteorological  monitoring
program be  Initiated  Immediately after  a site  1s  Included  on  the National
Priorities  List (NPL)  1f  representative  data  are not  available  from the
National Weather Service.  (In general, National Weather Service data will be
representative  of site conditions for simple, flat-terrain  settings.)   The
meteorological   monitoring program  should continue throughout  the post-NPL
phases.   Elements of  an  onslte meteorological  program  (e.g., recommendations
on the number and siting of meteorological stations) for a Superfund site are
discussed 1n Section 3.0 of this volume.

     Dispersion  meteorological  and  cllmatologlcal  data  available  from   a
National  Weather Service  (NWS)  station  or   other suitable  offslte  source
should  be  utilized.     From  a  practical viewpoint.   NWS  data   should   be
considered  1n  most  applications, since  such  data  are  subject to  reasonable
QA/QC  programs  and  are processed by the National  Climatic Center for  use  1n
dispersion models.  Data available from  state  or Industrial  facilities should
be  evaluated  for their  applicability, the availability of  parameters  needed
for  Input Into  the  dispersion calculations, and the QA/QC programs  they have
been subject to.   In  any event, dispersion meteorological  and  cllmatologlcal
data should be obtained from  a  station  that  1s considered  representative  of
the   general  dispersion characteristics  of  the  site.    Factors  such  as
proximity,  topography,   the   existence  of  water   bodies,   and  urban/rural
Influences  should  be   considered  1n  assessing  the  applicability  of  the
meteorological  data to the  site  under consideration.

      Data available  from  the NWS are  collected from  either 7-  or 10-meter
towers.  These heights are considered applicable for most Superfund low-level
 sources.    Data  from  NWS stations  are  also  applicable  to  the  potential
elevated  releases, either directly  or  through the use of  wind  power  law
 profiles.

      Table  2-5  provides  a   summary of  meteorological   data  for  use   1n
 dispersion modeling for Superfund APAs.

                                      2-23

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                              TABLE 2-5
A SUMMARY OF INPUT METEOROLOGICAL DATA FOR USE  IN DISPERSION MODELING
                          FOR SUPERFUND APAs
     Input Meteorological Data
                  Source
Length of Record
I. Superfund Step:   RI/FS.
   Remedial Design, Operation and
   Maintenance

   Hourly average wind speed
   Hourly average wind direction
   Hourly average atmospheric
   stability
   Minimum and maximum dally
   mixing heights
   Hourly ambient temperature
                NWS
                State
                Industlral
                Facilities
                (onslte)
•  one year
   minimum
•  five years
   preferred
(a longer data
set may be
appropriate
depending on the
potential
exposure period)
II.   Superfund Step:
      Action

A-Routine Releases
Remedial
   Hourly average wind speed
   Hourly average wind direction
   Hourly average atmospheric
   stability
   Hourly ambient temperature
   Estimated mixing height
             Onslte
             Meteorological
             Program
N/A
B-Non Routine Releases

   !5-m1n. average wind speed
   15-mln. average wind direction
   15-min. average atmospheric
   stability
   15-mln ambient temperature
   Estimated mixing height
             Onslte
             Meteorological
             Program
N/A
                                 2-24

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     Topographic features  and water  bodies  can affect  the dispersion  and
transport of  airborne  toxic  constituents.    It Is  therefore  Important  to
understand local  wind flows  and to  Identify areas  with  topography  and/or
water  bodies   that   might  Influence  the   dispersion  and  transport  of
constituents released from the site.   For example, a site located downslope
of an elevated  terrain  feature might be affected by  diurnal drainage flows.
Terrain  heights  relative  to  release  heights  will   affect  ground-level
concentrations.   Terrain obstacles  such  as  hills  and mountains  can divert
regional winds.   Valleys  can channel wind  flows and  also limit horizontal
dispersion.   In addition, complex terrain  can result  1n  the development of
local  diurnal   wind  circulations   and  affect  wind  speed,   atmospheric
turbulence,  and stability  conditions.   Although  difficult to  model,  such
situations should be recognized and quantified to the extent possible as part
of the  dispersion modeling analysis.   Topographic maps of the facility  and
adjacent areas  are needed  to  assess  local  and regional terrain.  The utility
of  an  on-site  meteorological  program  also  becomes  apparent  In  these
situations.

     Large water  bodies  can  also affect atmospheric  stability conditions  and
the  dispersion  of air contaminants.    In general, large water bodies tend to
Increase  the stability of  the  atmosphere  1n the air  layer adjacent to  the
water,  thus  reducing the dispersion  of air contaminants.   Local  diurnal  wind
patterns may  also be present  seasonally at coastal locations.   Again, onslte
meteorological  data  can be used  to Identify and  characterize these local  wind
patterns.

     Soil  characteristics  and  conditions  can  affect  air  emissions   from
Superfund  sites and the  wind erosion of contaminated  surface soils.   It 1s
therefore  Important  to understand  soil  conditions  such  as porosity,  silt
content,  particle size  distribution,  soil type,  and source data.

     Surface obstructions,  Including  structures, trees, and vegetation,  could
affect  air flow by generating wake effects  or Increasing plume dispersion due
to  surface   roughness.    It  1s  therefore  Important  to  obtain  pertinent
 Information  for use  In  the dispersion,modeling.
                                     2-25

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2.2.5     Previous APA Data

     Previous air quality data that address  calculated air concentrations of
constituents known  to exist at  the site can provide  Insight  Into existing
levels of air toxic constituents of  Interest.  Compound-specific Information
will be useful  1n assessing what  Indicator  compounds  should be modeled and
what nodellng  methodologies  should be  employed.    Site-specific  Superfund
documents  (e.g..  site Investigations  (Sis).  RI/FSs.  records of decision
(ROOs). etc.) should be reviewed to Identify  available APA Information.

     Results of existing  dispersion calculations  should  be  evaluated for
acceptability and  representativeness before  use.   Factors to  be  evaluated
Include

          Dispersion modeling  techniques employed.   These  Include modeling
          sophistication level  (I.e..  screening or refined).

          Input   data  used  1n the modeling.  Including  emission  Inventory.
          meteorology, and receptor grid.

          Assumptions used  to develop the  Input data base, the  quality of
          data used, and their applicability  to the case under consideration.

          Number of compounds modeled for and the assumptions Involved.

          Assessment of the quality of the dispersion modeling analysis.

     Existing air monitoring.data  for the site area can be used 1n designing
the receptor grid and selecting compounds to be modeled.  These data can also
be  used  In evaluating  the performance  of  dispersion  modeling by comparing
calculated  with measured  air concentrations.    Most  Importantly,  they can
provide Insight  on existing background concentrations.

          High accuracy of data to the extent possible and practicable
     •    Sound  methodology and assumptions used to derive the Input data
                                     2-26

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2.3       STEP 2  - SELECT MODELING SOPHISTICATION LEVEL

2.3.1     Overview

     Selection of the dispersion modeling  sophistication level and model  Is
the cornerstone for  a meaningful  Superfund  APA.  A  summary of this process  1s
presented  1n  Figure  2-3.    Coupled with  the  sophistication  level  Is the
applicability of  the  model  to the Superfund  site  and activity Involved and
Us  ability  to reasonably  simulate transport  and dispersion  of air  toxic
contaminants   from   the   sources   Involved.     The   appropriate  model
sophistication, applicability, and capabilities will depend  on the following
factors:

          Source-specific APA recommendations  presented 1n Volume  I

     •    Superfund  dispersion modeling objectives

          Data quality objectives for the dispersion modeling activities.

     •    Input data from Step 1

          Legal and  liability aspects of the Superfund project

     •    Pragmatic  aspects of the program

               Availability of good  quality  Input  data   and  the  constraints
               Involved

               Applicability of  existing dispersion models  to site-specific
               characteristics

               Ability of  existing  dispersion models to  reasonably simulate
               the   transport  and   dispersion  of  air   toxic contaminants
               released  from the  site,  considering  physical  and  chemical
               factors and  processes Involved
                                    2-27

-------
 SOURCE-SPECIFIC
         APA
RECOMMENDATIONS

     (Volume I)
  STEP  1  -  INPUT
        DATA

    (Section  2.2)
           AIR MODELING
            OBJECTIVES

             (Table 2-1)
            AVAILABILITY
          OF APPROPRIATE
              MODELING
            TECHNIQUES

        (Tables 2-6  end  2-7)
                      MODELING
                  SOPHISTICATION
                     (Figure  2-4)
               STEP 3 -
INPUT
  TO

D«v*lop Modeling
 Plan
  Flour* 2-3. Step 2 - 8*l*et Modeling Sophistication L*v»l.
                           2-28

-------
               Ability to accomplish the dispersion  modeling objectives with
               modest uncertainties,  and  the availability  of  the  required
               resources.

     Source-specific APA recommendations have been presented In Volume I. as
referenced  In  Figure 2-3.   These  recommendations  are  based on  a standard
sequence of APAs,  as Illustrated 1n Figure 2-4.   The APA strategy presented
1n Figure 2-4  1s  based  on the premise that Initially a screening APA should
be conducted.   The  need  for a  refined  APA  Is  then determined  based  on an
evaluation  of  screening results considering  the potential  to exceed health
criteria  (as  Indicated by  the Hazard  Index) and modeling  Inaccuracies  (as
Indicated by the Uncertainty Factor).

     The Hazard Index (HI) for systemic toxicants 1s determined as follows:
         n
   HIT = r
       1=1
where
     EI   =    exposure level of the 1th toxicant
     ALi  =    maximum acceptable level for the 1th toxicant
     n    =    total number of toxicants

The HI for carcinogens (Hie)  1s similar:
    Hie = i         — —                                       (2'2)
        J-l         DRJ

 where
     Ej   =    exposure level of the jth carcinogen
     DRj  •    dose at a set level of risk for  the Jth  carcinogen
     m    =    total number of carcinogens
                                     2-29

-------
                       CONDUCT
                      SCREENING
                           APA
                         EVALUATE
                      HAZARD INDEX
                      AND MOOEUNd
                   UNCERTAINTY FACTORS
                                  CONSIDER
                                  MODELING
                                  DETECTION
                                     LIMITS
                        CONDUCT
                         REFINED
                            APA
                             1
                          EVALUATE
                     HAZARD INDEX AND
                          MODELING
                    UNCERTAINTY FACTORS
                      (••• Flgur*  2-6)
                                                 INPUT TO
                                                'A I
                                                 Ml
Flflur* 2-4.
a«l«otlon of
Mod»ltng.
                                V»r«u« R*fln«d Ol»p«r»lon
                    2-30

-------
     If any calculated HI exceeds unity  (I.e.,  1), then health  criteria may
be exceeded.   However.  1t 1s also  necessary  to consider the  uncertainty  of
modeling results.  Because of these uncertainties, the air concentrations and
associated HI  values could  represent underestimates or overestimates of the
true HI  value.  Therefore, as  Indicated 1n Figure 2-5,  It Is  necessary  to
compare  HI  values  and  Uncertainty  Factor  (UF)  values  to  determine the
adequacy of  APA  results  to provide  exposure  Input data to  characterize the
potential health Impact  of Superfund air  emission sources.

     Based on  Figure 2-5,  1t  may be appropriate  to conduct  refined modeling
follow-up  to  screening  modeling  If  Information  Is  not  sufficient   to
definitively characterize the results.  Consider the following  example:

     •    HI   =    2    based   on   screening  modeling   results  (I.e.,
                         predictions Indicate  that health  criteria will  be
                         exceeded by a  factor  of 2)

          UF   »    ±5   for  modeling  results,   considering   the  combined
                         uncertainty 1n  the Input data and  the model  (I.e.,
                         modeling results  may  overestimate  or  underestimate
                         air concentrations by up to a factor of 5)

     For this case the HI value can be characterized as follows:

     UF>HI>1/UF                                                  (2-3)
     which 1s  equivalent to
     5.0>2.0>0.2                                                 (2-4)

     Therefore, for this  example,  based  on the evaluation criteria presented
 In  Figure  2-5,  It  Is  warranted  to  consider  the  conduct of  refined   air
modeling to  confirm modeling results.

     The  dispersion modeling  objectives  for  specific  Superfund  activities
 (e.g.,  RI/FS,  remedial action)  are  also  Important  Input for the  selection of
modeling sophistication levels.  These activity-specific objectives have been
 summarized  1n Table  2-1.   Input  from  the  RPM/EPM  should  be  obtained  to
                                     2-31

-------
               AIR PATHWAY ANALYSES
                MODELING/MONITORING
                       RB8ULT8
                       COMPUTE
                    HAZARD  INDEX
                          CHI)
                  UMeiftTAIMTV FACTORS
                          CSWW*
   HI >  UF
 UP > HI > 1/UP
 HI
1/UF
 Information  !•
 Sufficient To
 Cnaraotorlso
  Roloaao As
   Significant
  Information !•
  Not  Sufficient
  To Definitively
  Chsrsetorlzf)
  Tho  Roloaao
  Information la
  Sufflolont To
Cnaraotorlza
   Roioaao Aa
   Inaignlfloant
   INPUT TO
EPA REMEDIAL/
   REMOVAL
   DECISION
    MAKING
    ADDITIONAL
  AIR  PATHWAY
ANALYSES SHOULD
  BE CONSIDERED
   INPUT TO
EPA REMEDIAL/
   REMOVAL
   DECISION
    MAKING
   • UF Is aaumod to  bo  <. 1.O


   Flgura 2-6.  evaluation of  Hazard Indax and APA
              Uncertainty Faetora
                         2-32

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confirm site-specific dispersion modeling  objectives and to  ensure  that the
dispersion modeling level selected Is consistent with these objectives.

     The availability of appropriate  meterologlcal  data and modeling methods
1s probably the most significant factor for the modeling sophistication  level
decision-making.   Synthesized meterologlcal  data  are generally  limited to
screening  modeling  while  actual   meterologlcal  data are  appropriate for
screening  applications.   The capability  of dispersion models  to reasonably
simulate the transport and dispersion of air toxic contaminants released from
a Superfund site will dictate how far to carry dispersion modeling.

2.3.2     Selection of Models as a Function of Sophistication Levels

     A1r  dispersion models  are  employed  1n  a  wide  range  of  air quality
studies to provide spatial and temporal  fields of calculated  concentrations
due  to  air emissions  from  various  existing  and  proposed sources.   The
calculated  concentrations  are  used  to   fill  data  gaps  generated  by air
monitoring  programs that  cannot  provide  measured concentrations  at a  large
number  of  locations.  Dispersion models  provide a concentration  field  based
on the  use of  a large number of receptors and consideration of a wide  range
of  scenarios.    As  such,  air  dispersion models  serve as a  vital  tool  1n
assessing  compliance with regulations  for  existing  and  proposed  sources.
They also  are used  extensively 1n the regulatory development  process.

     The   air  dispersion  models  utilized  1n  air  regulatory  studies  can
conveniently be grouped  Into four classes:  Gaussian, numerical,  statistical
or  empirical,  and physical.  Of  these four classes,  the Gaussian models are
the  most   widely  used   because  of their   simple  formulation,   ease  of
understanding,  and their ability to simulate the transport and dispersion  of
air  contaminants for a  large number of  applications.  Most of the Gaussian
dispersion models employed  1n  air quality studies  are point  source models.
They are  the dominating  tools In all air  regulatory applications,  as noted 1n
the  EPA's Guidelines on  A1r  Quality Models.    The  four classes are  based  on
the following:
                                      2-33

-------
     •    Gaussian models are based  on the assumption that  plume dispersion
          1n  the  crosswlnd  and   vertical  directions   follows   a  Gaussian
          distribution In a  uniform wind  field.

     •    Numerical models   Include  the  continuity, •momentum,  and  energy
          equations that  are solved numerically  using  various  techniques.
          Plume  transport   Is  1n  a  nonunlform  wind  field.   These  models
          require  extensive  Input  and  substantial  computer  and  manpower
          resources.

     •    Statistical  or  empirical  models  Incorporate  factors  and  modules
          that are based on experimental  data.  Such models can be very site-
          specific and may  not  be  applicable  to most of the Superfund sites
          and associated activities.

     •    Physical models are based on the use of wind tunnels or other fluid
          (e.g..  water,  oil)  modeling   facilities.    They  require  major
          resources and  are  applicable  for  extremely  difficult situations
          that require  laboratory  simulations.   From  a  practical viewpoint,
          these models may not be applicable to Superfund APAs.

     Superfund APAs are one application of air dispersion  models,  with the
Gaussian dispersion models  being particularly useful.  The range of Gaussian
dispersion-type models applicable  to Superfund  APAs Is quite limited because
of the Superfund  source configurations and  characteristics.   As discussed 1n
Sections 2.1  and  2.2.2,  the majority of Superfund  sources are area sources,
followed by line and volume  sources.   Only  very few sources,  mainly those
present during the remedial  action  step,  are  classified as  point sources.
Since the majority of the Gaussian dispersion models are  for point sources,
the  selection of  dispersion  models  for  Superfund  applications  Is limited.
However,  the  models  available  are  considered  extremely  useful  tools  for
              •
Superfund APAs.

     Alternative  modeling  sophistication  levels   for   Superfund  APA
applications can be classified as follows:

     •    Screening models

                                     2-34

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          Refined models

     Screening dispersion models are applicable mainly for the screening step
of the RI/FS.  Their applicability and utility for any of the other Superfund
activities are very  limited.   Screening dispersion  model  analyses are based
on conservative assumptions and/or Input data.  Therefore, screening modeling
results provide conservative estimates of  air quality Impacts for a specific
source.   Screening dispersion  models are designed to  eliminate  the need for
further detailed  modeling  if they show  that  the Impact on  air  quality does
not  pose  a  risk  to  public  health  and  the environment.    If  results  of
screening dispersion calculations  indicate  a  potential risk to public health
and the environment, a refined modeling APA 1s warranted.

     Table 2-6 provides a summary of screening dispersion modeling  techniques
applicable  to Superfund  APAs.    The modeling  techniques  are based  on EPA
Guidelines  and  Workbooks  for  dispersion modeling  developed   for   similar
applications.  The  references  for the modeling  techniques are also included
1n  Table  2-6.   From Table 2-6,  1t  1s  apparent  that most  of the screening
modeling  techniques  apply  to  point  sources.   Such  models  can  be  used  in
screening  analysis  to  approximate other source  configurations,  such  as  area
sources,  but  the  calculations  involved   become  tedious.    The preferred
screening  techniques,  when  applicable,  for  Superfund  APA  applications are
based on  the use of  ISC 1n a screening mode and supplemented,  as  necessary  by
those stipulated  1n  A  Workbook of Screening Techniques  for  Assessing  Impacts
of  Toxic  Air Pollutants (U.S. EPA, 1988).

     Refined  dispersion models  utilize  analytical  techniques  that  provide
more  detailed treatment of the  physical  and  chemical atmospheric processes,
more  detailed and  precise  Input data,  and  more  specialized  concentration
estimates  than  the  screening  techniques.    These  models   consist   of
computerized  codes and can  handle massive  volume  of  Input  data (e.g.,  several
years  of hourly  meteorological  data).  Refined models generally  provide more
accurate  estimates  of the  Impact of Superfund  sources  on public  health  and
the environment.   Frequently  the conduct of a  refined dispersion  modeling
analysis  will involve a  "refined screening"  modeling as a  preliminary  step.
The purpose of  the refined screening  modeling  1s  to  Identify  locations  of
high  concentration  using  a  relatively  dense   calculatlonal  grid  network.

                                     2-35

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o»
                                                                            TABLE 2-6

                                      A SUMMARY OF  DISPERSION MODELING SCREENING  TECHNIQUES  FOR SUPERFIMD APAs  (page  1 of  2)

Feature
1. Source Configuration:
Point
Line
Area
VoluM
2. Release Node:
Continuous
Instantaneous
3. Contaminant Physical
State
Gas
Partlculate
4. Hake Effect
5. Downwash
Screening Modeling Technique
Guidelines for Air
Quality Maintenance.
Planning, and
Analysis. Volume 10
(Revised) Procedures
for Evaluating Air
Quality Impacts of New
Stationary Sources.
US EPA. 1977 (1)
Yes
No
No
No

Yes
No
Yes
Yes
No
No
A Workbook of
Screening Techniques
for Assessing
(•pacts of Toxic Air
Pollutants.
US EPA. March 1988
Yes
No
Yes
Yes

Yes
Yes*
Yes
Yes
Yes
No
workbook of
Atmospheric
Dispersion
EstlMtes.
0. Bruce Turner.
1969
Yes
Yes
Yes
No

Yes
Yes
Yes
Yes


Rapid Assessment of
Exposure to
Parttculate Emissions
from Surface
Contamination Sites.
US EPA. September 1984
No
No
Yes
No

Yes
No
No
Yes



ISC
Dispersion
Model (screening
mode)
Yes*
Yes*
Yes*
Yes*

Yes*
No
Yes*
Yes*


                *  Preferred technique when applicable

                (1)   These Guidelines are currently being revised and will  also Include a computerized model  SCREEN which carries  out the
                      screening calculations (should be available In 1989)

-------
                                                                           TABLE 2-6


                                     A SUNMRY OF DISPERSION MODELING SCREENING TECHNIQUES FOR SUPERFUND APAs  (page 2 of 2)
Feature
6. Heavier than Atr Gas
Nodule
7. Number of Sources
Handled
8. Concentration
Averaging Times
9. Conoents
Screening Modeling Technique
Guidelines for Air
Quality Maintenance.
Planning, and
Analysis. Volume 10
(Revised) Procedures
for Evaluating Air
Quality Impacts of Mew
Stationary Sources.
US EPA. 1977 (1)
No
Single
1, 3. and 24-hour s,
annual
Ibis document contains
f omul as and a large
timber of nooograros
for norm It zed
concentrations that
are useful for staple
screening
calculations. A
computerized version
of thts technique Is
tn the for* of the
PTPLU-2 node).
A Workbook of
Screening Techniques
for Assessing
Impacts of Toxic Air
Pollutants.
US EPA. March 1988*
Ves*
Single
Various
Averaging
Times*
This document
contains formulas
for screening hand
calculations. Also
Included are
examples of
calculations*
Workbook of
Atmospheric
Dispersion
Estimates.
D. Bruce Turner.
1969
No
Single
Various
Averaging
Times
This document
contains formulas
and a large number
of nomograms for
normalized
concentrations that
are useful for
simple screening
calculations. Also
Included are
examples of
calculations
Rapid Assessment of
Exposure to
Paniculate
Emissions from
Surface
Contamination Sites.
US EPA. September
1984
No
Single
24 Hour and Annual
This document
provides a
methodology for
screening estimates
of air
concentrations from
surface releases
from Super fund sites
and alike.
ISC Dispersion Model
(screening mode)
No
Multiple*
1. 3. 8 and 24-hours
and annual
The ISC dispersion
model combines
various dispersion
algorithms Into a
set of two computer
programs that can be
used to assess the
air quality Impacts
of emissions from a
wide variety of
sources.
f\>
I
            * Preferred technique when applicable


            (I)   These Guidelines are currently being revised and will also Include a computerized model  SCREEN which carries out the screening

                 calculations (should be available  In 1989)

-------
Thus,  the  refined modeling  analysis  can  be  conducted  1n  a cost-effective
manner by limiting the calculatlonal  grid  points to those which characterize
actual receptor locations and high  concentration areas of concern on a site-
specific basis.  Frequently, the same model  can be used for both the refined
screening  and  refined  modeling  analyses.    Further  reference to  refined
modeling APAs  in  Section  2  1s based  on  this two-step process which Includes
the conduct of a refined screening analysis, as warranted.

     Refined dispersion modeling  provides  the  user  with  high flexibility by
accommodating multiple sources and providing a  concentration field for varied
time averages at a large number of receptors, none of which could be obtained
from hand calculations  using  screening methodologies.  Table 2-7 provides a
summary of refined dispersion models applicable for Superfund APAs.

     The Industrial Source  Complex  (ISC) dispersion  model,  the Point, Area,
and  Line  Dispersion  Deposition  (PAL DS)  model,  and  the  Mesoscale   Puff
(MESOPUFF  II)  model  are  Included  1n the  EPA's Guideline  on  Air  Quality
Models.  The ISC dispersion and  PAL  DS models are  applicable to continuous
sources with  several  configurations,  while  the MESOPUFF  model 1s applicable
to  Instantaneous  releases  and can  handle  point and area  sources.   Of these
three, the  ISC dispersion model  1s  the preferred model for most applications
and  should  be  selected  as the model  of choice for  use 1n the Superfund  APA
for the RI/FS, remedial design, and operation and maintenance  activities.   It
can  be augmented  as required  by the  use of  the MESOPUFF  II,  Integrated  Puff
(INPUFF), or Dense Gas  Dispersion  (DEGADIS)  models 1f  special  air release
situations exist that could be simulated by any of these models.

     The ISC dispersion model  should also  be used  as the  model  of choice
under  the  remedial action  activities to  simulate  routine air  releases.  A
model  like  the  INPUFF  or  the  procedure  outlined  1n  Appendix C  should  be
utilized for APA under nonroutine air  releases.

     In this respect, the  ISC dispersion model  can be  considered the default
air  dispersion model  for  Superfund  APA applications.    (The  ISCLT  model  is
also  Included  1n  the  EPA's  Graphical  Exposure  Modeling System,  which  is
standard for use 1n conducting Superfund risk assessments.)
                                     2-38

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                                       TABLE  2-7



 A SUMMARY OF DISPERSION MODELING REFINED TECHNIQUES FOR SUPERFUND APAs  (page  1 of 2)
Feature
1. Source Configuration
Point
Line
Area
Volume
2. Release Mode
Continuous
Instantaneous
3. Contaminant Physical State
Gas
Partlculate
4. Make Effect
5. Downwash
6. Heavier than Air Gas Module
7. Number of Sources Handled
8. Number of Meteorological
Towers
Modeling Technique
ISC
Dispersion
Model 1*

Yes*
Yes*
Yes*
Yes*

Yes*
No

Yes*
Yes*
Yes*
Yes*
No
Multiple
Single
PAL OS Modell

Yes
Yes
Yes
No

Yes
No

Yes
Yes
No
No
No
Multiple
Single
INPUFF2

Yes
No
No
No

Yes
Yes

Yes
No
No
Yes
No
Single
Multiple
DEGAOIS3

Yes
No
No
No

Yes
Yes

Yes
No
No
No
Yes*
Single
Multiple
* Preferred techniques when applicable

-------
ro
k
                                                        TABLE 2-7
                  A SUMMARY OF DISPERSION MODELING REFINED TECHNIQUES FOR SUPERFUND APAs (page 2 of 2)
Feature
9. Concentration Averaging Time
10. Applicability to Superfund
Activities
Modeling Technique
ISC
Dispersion
Modell*
1,3,8, and
24 hour,
annual
All steps
(1) Included In the EPA Guideline on Air Qual
ISC = Industrial Source Complex; PAL OS =
Deposition; MESOPUFF = Mesoscale PUFF mod
PAL OS Modell
1 through 24
hours
All steps
INPUFF2
Hourly
Remedial
Action
Step
ity Models (Revised), July 19
Point, Area, and Line Source
el;
DEGADIS3

Remedial
Action
Step and
Selected
Use for
Other
Steps
B6;
Dispersion
                 (2)    US EPA INPUFF = A single source Gaussian Puff Dispersion Algorighm -  Users  Guide;
                       INPUFF = Integrated Puff
                 (3)    US EPA, Dispersion Model for Evaluating Dense Gas  Jet  Chemical  Releases  Vol  1  and
                       2, April, 1988; DEGADIS = Dense Gas Dispersion
                    Preferred technique when applicable

-------
     Other Guideline models,  such  as the Multiple  Point  Gaussian Dispersion
Algorithm  with   Terrain  Adjustment  (MPTER)  model,   CRSTER  model,   and
CUmatologlcal Dispersion  Model  (COM  2.0),  are  not  considered useful  for
Superfund APA applications.

     The  INPUFF  and   the  DEGADIS  models  were   Included  for   handling
Instantaneous  releases,  with  the  DEGADIS  model  having  the capability  to
handle heav1er-than-a1r gases.  These two models could be useful  as a part of
the remedial action step on a case-by-case basis.

2.4       STEP 3 - DEVELOP MODELING PLAN

2.4.1     Overview

     A dispersion modeling plan should  be  developed for  each Superfund APA
application.   The objective  of  the plan  1s  to document the modeling methods,
Input data requirements  and  modeling output  and use, consistent  with the APA
objectives  and  the dispersion modeling  DQO.  The  plan  also   provides  an
opportunity  for  peer  review and  RPM/EPM approval  of  the modeling program.
The modeling  plan becomes  an Integral  part  of the Superfund APA.   Developing
a modeling plan Involves the following major elements:

          Select constituents to be modeled
          Define emission  Inventory methodology
          Define meteorological data base
      •    Design receptor  grid
      •    Detail modeling methodology
      •    Estimate background concentrations
          Define dispersion calculations to be performed
      •    Document modeling plan.

      Major  Input to the  development of  the  dispersion modeling plan  should
 Include  the  Information collected  under  Step 1  (Collect  and  review  Input
 Information)  and  Step  2  (Select modeling sophistication level.)

      Procedures  for  development  of a dispersion modeling  plan are provided  in
 the subsections  that follow.  Table 2-8 provides an outline  for the modeling
                                     2-41

-------
                                  TABLE 2-8
       AN OUTLINE FOR THE DISPERSION MODELING PLAN FOR A SUPERFUND APA
I.     INTRODUCTION
          General  site  background  (site  location,  topography,  nearby  water
          bodies, demography,  vegetation,  general  site activities)
II.    DISPERSION  MODELING DATA QUALITY  OBJECTIVES
          Modeling   objectives   (consistent   with  the   Superfund  activity
          involved  and the overall  project objective
      •   Overall rationale for  the modeling  approach
          Modeling  uncertainties and their implications to the Superfund APA
III.  CONSTITUENTS  TO BE MODELED
IV.    EMISSION INVENTORY
      •   Sources to  be modeled  (number;  configuration  (i.e.,  point,   line,
          area volume); locations)
          Source  characteristics (constituents Involved)
          Methods for estimating emissions (see Volumes II and III)
          Content of the emission inventory database (see Table 2-4)
          Particle  size distribution
          Physical  and chemical  properties of constituents to be modeled
          Dimensions of obstructions
V.    METEOROLOGICAL DATA
       •   Source of meteorological data
       •   Length of record
          Parameters to be utilized in the dispersion modeling
          Quality of the data
VI.    RECEPTOR GRID
          Ons1te receptors (number and locations)
       •   Perimeter receptors (number and locations)
       •   Offsite receptors
               Regular  (number and locations)
                                      2-42

-------
                                  TABLE 2-8

 AN OUTLINE FOR THE DISPERSION MODELING PLAN FOR A SUPERFUNO APA  (Continued)


               Anticipated  locations  of   high   concentration   (number   and
               locations)

               Environmentally sensitive locations (number and locations)

VII.  MODELING METHODOLOGY

      •   Selected model(s)  and rationale
          Model application  to the Superfund activity APA
      •   Model features

               Rural/urban classification
               Wake and/or downwash effects
               Particle deposition
               Plume rise
               Dispersion  parameters

      •   Setting of model switches
      •   Testing the model  against bench mark test cases

VIII. ESTIMATED BACKGROUND CONCENTRATIONS

XI.   DISPERSION CALCULATIONS

      •   Averaging times
          Data summaries  (tabular, graphical)
          Comparison with  guideline values
          Input to the risk  assessment

X.    REFERENCES
                                     2-43

-------
plan.  Each of  the  major elements of the  modeling plan is discussed  1n  the
following subsections.

2.4.2     Dispersion Modeling  Data Quality  Objectives

     The  purpose of  this section 1s  to outline the  main objectives  of  the
dispersion modeling  as  a part of the Superfund APA and  how to  meet  them.   It
should address  applicable  or relevant  and appropriate  requirements  (ARARs)
for each  of the Superfund activities  and the level  of air dispersion modeling
that 1s necessary to provide adequate Input Into  the  Superfund  APA.

     Elements  included  1n this section should  address

          The  overall rationale for the  modeling  approach

          Model  output  and anticipated uncertainties, considering Input data.
          model  formulation and assumptions Involved,  and output

          Implications  of model uncertainties  on the  Superfund APA (e.g., are
          they acceptable)

     In  this  respect,  dispersion   modeling   DQOs  provide   consistency  1n
selection  of  the  modeling   tool,   modeling  Input   (emission  inventory,
meterological  and other data) and output,  and in the overall  requirements of
the  air dispersion modeling for the  specific application under consideration.

2.4.3     Select Modeling Constituents

     Selection  of  air  toxics  constituents  for  dispersion  modeling  is
generally  less  critical  than for monitoring  APAs.   Selection of monitoring
constituents  1s significantly  limited  by technical,  budget,  and schedule
constraints.     However,  dispersion   modeling   results  from   one   target
constituent for  a particular  source  can generally be  scaled  to  obtain, on  a
cost-effective  basis,   concentrations  for numerous   other  constituents  of
interest.
                                     2-44

-------
     A  summary  of  the  recommended  procedure  for  selection  of  dispersion
modeling target constituents 1s presented 1n Figure 2-6.

     A 11st of the compounds Included  In the Hazardous Substances List  (HSL)
developed by EPA for the  Superfund  program 1s presented  1n  Table  2-9.  This
11st Is a composite of  the Target Compound List (TCL) for organlcs and Target
Analyte  List  (TAL) for  Inorganics.    Table 2-9  also  Includes  examples for
additional potential Superfund  air  emission  constituents   (e.g.,  HCN,  H2S,
HC1).  Therefore,  Table 2-9 represents a comprehensive  Initial  11st of target
compounds for air  dispersion modeling for Superfund APA.

     Emission rate  APA results  should  be obtained  prior to the  conduct of
dispersion studies based on Volume I recommendations.  These results, as well
as  dispersion  modeling results  (as  available),  should be  used  to Identify
appropriate site  and  source-specific modeling  constituents from  Table 2-9.
In  addition, constituents  Included  1n ARARs Identified during  Step 1 should
also be used to Identify candidate modeling constituents.

     The  limited  set  of  candidate  modeling  constituents based  on previous
APAs and  ARAR  considerations should be  used  to compute  constituent-specific
HI  values.   Instructions for computing  HI values were presented  1n Section
2.3.

     The  HI values  computed  should  then be ranked from highest to lowest 1n
order  to develop  a priority 11st of  candidate modeling constituents.   The
final  constituents  selected  for dispersion modeling  should  be  a function of
the APA sophistication  level (as Indicated 1n Figure 2-6).

     Dispersion modeling  for  screening  applications  should  Include  all
site/source-specific constituents.

     Dispersion modeling  target constituents for  refined APAs  should,  at  a
minimum,  Include all constituents with an  Individual  HI value greater than or
equal  to 10 percent of the composite  HI  value  for  the total mix.    These
constituents are expected to represent the greatest contributors to potential
health  Impacts.  This  approach  provides  a practical  basis to address refined
modeling  APAs at sites with a large number of potential emission constituents
                                     2-45

-------
 AIM CONCENTRATION
•ST1MATV8 SA3BO ON
  CMiaaiONS DATA
    9trm* 1  INPUT
     (T«bl«  2-3)
 PREVIOUS OISPBRSION
MONITORINOXMOOCUNO
 DATA - ST«P  1 INPUT
      (Tabl* 2-3)
    SUPERFUNO
HAZARDOUS  SUB
  STANCES LIST
    (Table 2-9)
ARARa - STEP
       INPUT
    (Tabld 2-3)
                         COMPUTE
                      CONSTITUENT-
                    SPECIFIC HAZARD
                    INDEX (HI) VALUES
                           RANK
                             HI
                         VALUES
          SCREENING
 REFINED
MODEL ALL APPROPRIATE
 siTtxsouRCE-spc
     CONSTITUENTS
         AT A MINIMUM.
    	   UOMB TITUBN f •
   WITH HI  0.1 HI (TOTM. MIX)
              U. srrcx
        OOM»IIIUgKT» TO
                          INPUT TO
                       AIR MODELING
                            PLAN
       RMVALUATC TAROBT
         LIST BASED ON
      CURRENT MONITORINQX
       MOOCUNQ RESULTS
                       2-46

-------
             TABLE 2-9 (PAGE 1 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
        FOR AMBIENT AIR MODELING STUDIES
Broad Band
Volatile Organic*




-































Compound Class
Aliphatic*
Aromatics





Halogenated Species





















Oxygenated Species



Sulfur-Containing
Species
Nitrogen-Containing
Species
Representative Compounds
vinyl acetate
benzene
toluene
ethylbenzene
total xylenes
styrene
chlorobenzene
carbon tetrachloride
chloroform
methyl ene chloride
chloromethane
1,2-dichloropropane
trans - 1 , 3-d 1 ch 1 oropropene
c1s-l,3-d1chloropropene
bromoform
bromomethane
bromod 1ch 1 oromethane
d 1 bromoch 1 oromethane
1 , 1 , 2,2-tetrachloroethane
1,1,1-trichloroethane
1,1,2-trichloroethane
1,1-dfchloroethane
1 , 2-d 1 ch 1 oroethane
chloroethane
tetrachloroethene
trlchloroethene
1,2-dichloroethene
I,l-d1chloroethene
vinyl chloride
acetone
2-butanone
2-hexanone
4-methyl-2-pentanone
carbon disulflde

benzonitrile*

                      2-47

-------
             TABLE 2-9 (PAGE 2 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
        FOR AMBIENT AIR MODELING  STUDIES
Broad Band
Volatile Inorganics

Semi -Volatile
Organics



Compound Class
Acid Gases
Sulfur Containing
Species
Phenols
Esters
Chlorinated Benzenes
Amines
Representative Compounds
cyanide*
hydrochloric acid*
hydrogen sulfide*
phenol
2-methylphenol
4-methylphenol
2 ,4-di methyl phenol
2-chlorophenol
2,4-dichlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
pentachlorophenol
4-chloro-3-methyl phenol
2-nitrophenol
4-nitrophenol
2,4-dinitrophenol
4, 6-dinitro-2-methyl phenol
b1s(2-ethylhexyl)phthalate
di-n-octyl phthalate
di-n-butyl phthalate
diethyl phthalate
butyl benzyl phthalate
dimethyl phthalate
1,2-dichlorobenzene
It3-d1chl orobenzene
1 , 4-d 1 ch 1 orobenzene
1,2,4-trichlorobenzene
hexach 1 orobenzene
nitrobenzene
2,6-dinitrotoluene
2,4-d1nitrotoluene
3,3'-dichlorobenz1dine
n-n1 trosodimethy 1 ami ne
n-n i trosod 1 -n-propy 1 ami ne
n-ni trosodipheny 1 ami ne
aniline
2-nitroan1line
3-nitroan1l1ne
4-nitroaniline
4-chloroannine
                        2-48

-------
                     TABLE  2-9  (PAGE  3  OF  4)

        CLASSIFICATION OF ORGANIC AND INORGANIC  COMPOUNDS
                FOR AMBIENT AIR MODELING STUDIES
Broad Band
Compound Class
Representative Compounds
                 Ethers
                   bis(2-chloroethyl)ether
                   bis(2-chloroisopropyl)ether
                   bromopheny1-pheny1 ether
                   4-chlorophenyl-phenylether
                 Alkadlenes
                   hexachlorobutad1ene
                   hexach1orocyc1opentad1ene
                 Miscellaneous
                 Aliphatics and
                 Aromatics
                   benzole acid
                   benzyl alcohol
                   bis(2-chloroethoxy)methane
                   dibenzofuran
                   hexachloroethane
                   isophorone
                 Polynuclear Aromatic
                 Hydrocarbons (PAHs)
                   acenaphthene
                   acenaphthylene
                   anthracene
                   benzo(a)anthracene
                   benzo(b)f1uoranthene
                   benzo(k)f1uoranthene
                   benzo(g,h,i)perylene
                   benzo(a)pyrene
                   chrysene
                   dibenz(ath)anthracene
                   fluoranthene
                   fluorene
                   1ndeno(1,2,3-cd)pyrene
                   naphthalene
                   2-methy1naphthalene
                   2-chloronaphthalene
                   phenanthrene
                   pyrene
                 Pesticides
                   alpha-BHC
                   beta-BHC
                   delta-BHC
                   gamma-BHC
                   heptachlor
                   heptachlor epoxide
                   4,4'-DDT
                   4,4'-DDD
                   4,4'-ODE
                   endrin
                   endrin  ketone
                   endrin  aldehyde
                               2-49

-------
                          TABLE 2-9 (PAGE 4 OF 4)

             CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
                      FOR AMBIENT AIR MODELING STUDIES
      Broad  Band
    Compound Class
   Representative Compounds
                       Pesticides
                       endosulfan I
                       endosulfan II
                       endosulfan sulfate
                       aldrin
                       dieldrin
                       chlordane
                       methoxychlor
                       toxaphene
                       Polychlorinated
                       Biphenyls  (PCBs)
                       Arochlor 1016
                       Arochlor 1221
                       Arochlor 1232
                       Arochlor 1242
                       Arochlor 1248
                       Arochlor 1254
                       Arochlor 1260
Non-Volatiles
Inorganic Metals and
Non-Metals
aluminum
antimony
arsenic
barium
beryllium
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
mercury
nickel
potassium
selenium
silver
sodium
thallium
tin
vanadium
zinc
Note:  Compounds  identified  by  an  asterisk  (*)  are  not  contained  on the USEPA
Hazardous Substance List  (HSL).
                                     2-50

-------
(e.g., over one hundred) of which only a  limited  subset significantly affect
Inhalation exposure  estimates.    However,  it  1s  generally  recommended,  as
practical, to also evaluate all  appropriate site/source-specific constituents
for  refined  modeling  APAs  (especially  1f the   cumulative  effect  due  to
exposure  to  a mixture  of  constituents  1s used  for  comparison  to  health
criteria).

     The dispersion modeling target constituents  11st  should be reevaluated,
and revised 1f warranted,  based  on monitoring results.

     It 1s recommended  that dispersion modeling results Initially be obtained
1n  terms  of dispersion  factors  (I.e..   concentration  divided by  a  unit
emission  rate).   This  will  provide  a cost-effective  basis  for estimating
receptor exposure concentrations for a wide variety  of emission constituents
(I.e., a  constituent-specific concentration equals the  dispersion  factor of
the  receptor location  of  Interest  times  the  constituent-specific emission
rate).

2.4.4     Define  Emission  Inventory  Methodology

     Emission  Inventory  1s  a  key  Input  to  the Superfund  air dispersion
modeling.  Data  obtained  from Step  1 (Collect and review Input  Information)
should be utilized 1n determining the number and  nature of sources Involved.
The modeling plan should outline the procedures for

          Estimating  the dimension  of the  sources Involved.   This Includes
          estimating  the contaminant distribution  and  defining the shape and
          boundaries  of  sources.

     •    Classifying  sources   by   configuration—area,  line,  volume,  and
          point—and  subdividing them as necessary.

     •    Determining coordinates of the sources.

     •    Defining the  constituents involved  with each source  based  on the
          output  of Section 2.4.2.
                                     2-51

-------
          Defining  the parameters required for  estimating  emissions that are
          Identified   1n  Volumes  II  and  III,  and  the  rationale  for  their
          selection.

     •     Calculating  emissions based on  methods outlined  1n  Volumes  II and
          III.

     •     Estimating  particle  size  distribution for  calculating participate
          deposition.

     •     Accounting for  downwash from nearby structures.  This phenomenon 1s
          particularly Important for onslte air strippers and  Incinerators at
          Superfund sites.   These units  frequently  have  low  stack heights.
          Therefore, releases from these stacks may be Influenced by adjacent
          structures.

     •     Estimating the  dimensions of obstructions and  the distance of such
          obstructions from the sources  under consideration.

     Program design objectives and OQOs  should be an Integral  part  of the
methodology outlined.

     The emissions  Inventory should be tabulated 1n a format suitable for use
1n dispersion  modeling.    This  table  should  Include physical  and chemical
characteristics of  the constituents to be modeled.

     As  discussed  1n  Sections  2.1  and  2.2.2, most of  the  Superfund air
release sources are area sources, followed by line  and volume sources and to
a  lesser extent by point  sources.    Many of  the  area  sources  at Superfund
sites have  Irregular  shapes  and many cover a  large area (e.g., many acres).
The  ISC  dispersion  model  handles  area  sources  only  as  squares.    To
accommodate  the  ISC   model   Input  requirements,  1t may  be  necessary  to
subdivide  a Superfund area  source Into  a number of smaller area sources,
square 1n shape.   Source subdividing  Into small, square area  sources has the
following two major benefits:
                                     2-52

-------
     •     The  areas and  shapes  of Irregular  sources  can be  approximated  1n
          most  cases by a number  of  small  squares, as  Illustrated  1n Figure
          2-7.

     •     Receptors at  or  near  the  source  can  also  be  Included  1n  the
          dispersion modeling, as  often  required for the Superfund APA.   This
          Includes  receptors  at  onslte work areas,  at  the site perimeter, and
          Immediately offslte.

     A   specialized modeling approach   1s generally  needed  for   standard
Gaussian dispersion models such as the  ISC, 1n  order  to obtain concentration
estimates near  the  boundary  of  a large area source.  For example, the nested-
area  subdivision  approach   Illustrated  1n  Figure  2-8 can be  used.     By
subdividing the area source  such that the square nearest the receptor 1s less
than 10  meters  on  a side,  1t   1s  possible for  the ISC dispersion  model  to
provide estimates of concentration within 1 meter of the source boundary.

     Models, which simulate the  mlcroscale  physics   Immediately  above  a
ground-level emission  surface,  can also  be  used  to estimate concentration at
and 1n  the  vicinity of an  area source.   Although these flux  models  can be
technically sophisticated, they generally  lack extensive validation  and are
not recommended as  preferred models for  Superfund APAs.

2.4.5     Define Meteorological  Data Base

     Meteorological data are also  key  Input to  the dispersion calculations.
As  noted,  Input meteorology governs  the  transport  and  dispersion of the
contaminant plume.   It  1s therefore Imperative to select the most appropriate
meteorological  data.  For most  Superfund activities (RI/FS, remedial design,
and operation  and  maintenance),  historical data  are very  useful.    In the
absence  of a   long  record  of  onslte   data,  data  applicable  for  use  1n
dispersion  modeling  are  generally  available  from  NWS   stations,  state
meteorological  programs, and private  Industry.   Generally  at least one year
of  meteorological  data should  be  available for screening  analyses.   It 1s
desirable to have  five or more  years of meteorological  data to support  long-
term exposure assessments for refined APAs.
                                     2-53

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FIGURE 2-7    REPRESENTATION OF AN IRREGULARLY SHAPED AREA SOURCE
                                     2-54

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                        Wind Direction
Receptor at
site boundary
Nested subdivisions, as
necessary to yield areas
of <100m2
                           FIGURE 2-8
         EXAMPLE OF NESTED SUBDIVISION OF AREA SOURCE
                            2-55

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     As discussed  In Section 2.2.4,  onslte meteorological data should be used

     •    To determine  how well offsite data correlate with It

     •    To provide site specific data showing the diurnal variations of the
          meteorological  parameters  and the effects  of topography and nearby
          water bodies on the transport and  dispersion  of  the  air toxics
          plume

     •    Define  worst-case  emission/dispersion scenarios  to conservatively
          evaluate  short-term exposure  conditions  to  support screening APAs.

     The data base  selected  should

     •    Meet program  and DQO objectives

     •    Have a record of sufficient length

     •    Include data  representative of the site  area

     Meteorological  data  may be used to define worst-case emission/dispersion
scenarios  to  conservatively estimate  short-term  exposure  conditions  to
support screening  APAs.  For example,  this  approach  would be appropriate for
use of ISCST for a screening APA.  However, for a refined APA based on ISCST
a sequential file  of hourly meteorological  data may  be warranted as modeling
Input.

The  quality of the meteorological  data  should  meet  EPA  requirements  as
outlined In the following technical  references:

     •    U.S. EPA.   June 1987.    On-S1te  Meteorological  Program Guidance for
          Regulatory Modeling Applications.   EPA-450/4-87-013.  Office of A1r
          Quality Planning and Standards.  Research Triangle Park, NC 27711.

     •    U.S. EPA.    February  1983.    Quality Assurance  Handbook  for  Air
          Pollution   Measurements  Systems:     Volume   IV.     Meteorological
                                    2-56

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         Measurements.    EPA-600/4-82-060.     Office   of   Research   and
         Development.  Research Triangle Park. NC  27711.

         U.S.  EPA.   July 1986.   Guidelines on Air Quality Models  (Revised).
         EPA-405/2-78-027R.    NTIS  PB  86-245248.    Office of  A1r  Quality
         Planning and  Standards.   Research Triangle Park.  NC  27711.

         U.S.  EPA.    November  1980.    Ambient  Monitoring  Guidelines  for
         Prevention  of Significant  Deterioration  (PSD).   EPA-450/4-80/012.
         NTIS  PB 81-153231.   Office of  A1r Quality  Planning  and  Standards.
         Research Triangle Park. NC  27711.

     The modeling plan should also Identify the following  Information   with
respect to  the  meteorological data  set:

     •   Source  of meteorological  data and  rationale  for selecting this data
         base.   This applies to both surface and upper-air data.

     •   Length  of record.   A minimum of 1 year of hourly data 1s required,
         with  5  years  of  data being  preferred.

         Parameters  to be utilized  1n  the dispersion model,  Including wind
         speed,  wind direction, atmospheric stability,  ambient temperature,
         and mixing  height.

     An  onsite' meteorological  program  1s  recommended  1n the  case of  the
remedial action  step.    Section  3.0 addresses  the  requirements  of  onsite
meteorological  programs for that step.   Even flat terrain sites with nearby
National Weather  Service  data   should  Install  and  operate  an  onsite
meteorological  station during remedial actions.   The  short-term temporal and
spatial  variability  of wind  conditions  limits  the applicability  of offsite
meteorological  data  for realtime  decision-making  (e.g..  during non-routine
air  releases).   Data collected  through  this  step  can be  utilized  as
historical   data  1n  making  the  dispersion calculations   and   1n  assessing
routine  air  releases,  or  as  near  real  time data 1n estimating  the Impact of
nonroutlne  air  releases.   The  modeling  plan  for the remedial action step
                                     2-57

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should address the use of onslte meteorology  1n  dispersion modeling for both
routine and nonroutlne releases.

     Meteorological   parameters   used  for  each  application  should  be
Identified, and an explanation  should  be given of their use.

2.4.6     Design Receptor Grid

     The  selection of  the  proper  number  and   locations of  receptors  1s
paramount  for  a meaningful dispersion  modeling   analysis.   It  is  therefore
Important to carefully select  receptors  to ensure that the areas of potential
Impact Include the desired spatial  distribution of receptors.

     A receptor grid or network for a Superfund  air dispersion model defines
the locations of calculated air concentrations that are used as a part of the
APA to assess the effect of air releases  on human health and the environment
under the various Superfund site  activities.

     The process of setting the  receptor  grid should  meet the following APA
objectives:

     •    Providing concentration estimates which can be used as Input to the
          Superfund risk assessment process and to compare to ARARs

          Providing technically  sound spatial distribution of  receptors to
          account  for areas  exhibiting   large  concentration  gradients over
          short distances,  by  Increasing   the  density of  receptors at  these
          locations and  ensuring  that locations of  high  concentrations are
          not missed

     It 1s therefore  Important to establish a receptor grid that will  address
both  the  locations of anticipated maximum air  toxics  concentration and the
air  toxic  concentrations  at  environmentally  sensitive  receptors  such as
residences, work areas, schools,  hospitals, parks, and monuments.

     Concentration averaging times should be a factor  in setting the  receptor
grid  based on the APA objectives.   For short-term averaging  times  (up  to 24

                                     2-58

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hours), the  selection  of receptors  should  be based  on  the  objective  of
protecting public health and  the environment at all publicly accessible areas
around the  Superfund site.    In this  respect the  receptor  should Include
locations  of  anticipated maximum  air  toxics  concentration  offsite.   With
respect to  long averaging times (monthly,  seasonal,  annual,   70  years,  or
others) air  toxics  concentrations  should  be  evaluated  at  actual receptor
locations   (I.e.,  1n areas  surrounding  residences,  work  places,  and  at
locations  with environmentally  sensitive species).

     From  a practical viewpoint, most of the Superfund release sources can be
regarded  as ground-level sources.  Only a few of them are elevated, and even
they are classified  as  low-level elevated sources.   Examples Include onslte
structures  and  onsite  treatment  facilities  (e.g..  Incinerators,  air
strippers).    This  Implies that, for most  releases from Superfund sources,
high-ground-level concentrations of air toxics  will  occur at short distances
from  the  source.   Depending  on the  source configuration  and  the release
height, such concentrations will occur  less than  1  to  2  kilometers from the
source

     For  Superfund APA  modeling applications to Identify high  concentration
areas (I.e., generally for modeling planning purposes) 1t 1s recommended that
the receptor grid spacing for  the  area within  2 kilometers  of the source be
approximately  200  meters, depending  on  the  number  of  sources  and  their
configuration.   The  receptor grid spacing  for areas more  than 2  kilometers
from  the  source could  be 1  to 2 kilometers up  to  10  kilometers from the
source; for  areas   than  10  kilometers  from  the  source.  It  could  be  5
kilometers.    This  basic grid  network  should be supplemented  by receptor
points of  Interest (e.g., houses, schools, etc.) on a site-specific basis.  A
polar or rectangular grid could be used for these  applications based on these
receptor grid criteria.

     The receptor  grid  system  for  Superfund APAs should be  developed on a
case-by-case basis and should consider:

     •    Results of the receptor  data  evaluation performed  under Section
          2.2.3
                                     2-59

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          Results  of  screening  and  refined  screening  dispersion  modeling
          estimates of  locations of  high  concentrations may  be useful  to
          reduce the  receptor grid size  for  refined analyses

     •    Prevailing  wind  direction

     •    Meteorological conditions  conducive to high concentrations

          Population  distribution In the site vicinity (Section 2.2.3)

          Sensitive receptor locations

          The number  and configuration of sources

          Release characteristics such  as height,  dimensions,  and proximity
          to the site  perimeter

     •    Work areas  on the site

     •    Locations of air monitoring  stations

     •    Screening analyses, especially  for short-term exposure evaluations
          may be  based  on  worst-case meteorological scenarios  which  -assume
          Invariant  wind   conditions.    Therefore,  for a  single  source
          evaluation  based  on these conservative  assumptions,  the screening
          analysis calculatlonal  grid  points may  be  limited  to the plume
          centerline  for the downwind  sector of Interest.

     These factors should  be  considered in  selecting onsite, perimeter, and
offsite  receptors.    The  rationale  for the selection  of   the  number  and
locations of  each type  of  receptor  should be  stated.    Depending  on  the
specific application,  the  number  of  receptors could range  from 200 to 400.

2.4.7     Detailed Modeling Methodology

     The modeling methodology 1s based   on  the objectives outlined  in Table
2-6 for dispersion modeling as  a function of  the  Superfund  activity,  and it

                                    2-60

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1s consistent with the OQOs for the  project.   As discussed 1n Section 2.4.2,
1t 1s  necessary  to determine the  level  of sophistication  of the dispersion
modeling,  the Input  data  requirements,  and  the  quality  of  data.    This
determination  will permit  assessment  of  the  costs  and  benefits  of  the
modeling methodology  and the effects of  the uncertainties  Involved  on the
Superfund APA.

     Screening modeling 1s desirable for

          Obtaining  rough  estimates  of  the   levels  of  air  "contaminant
          concentrations and the approximate locations of high concentrations

          Providing Information on the need for refined dispersion modeling

     Techniques for performing screening dispersion calculations  are provided
1n Table 2-6.

     The selected methodology should take Into account the following:

     •    Screening versus refined modeling applications

     •    Formulation to be used

          Applicability  of  the  approach to the Superfund  activity  and  source
          under consideration

          Concentration  averaging time

          Special  considerations such as heav1er-than-a1r  gas

      •   Dispersion parameters

           Plume  rise considerations

      •    Quality and quantity  of meteorological  data available  (e.g.,  the
           availability  of representative data  recommended  to support  refined
           dispersion modeling analyses)

                                      2-61

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     For refined dispersion modeling, the model to be used should be selected
from Table  2-7.   The  ISC  dispersion model  1s the preferred  model  for most
Superfund APAs.    When  there  1s  a  need  for  characterizing Instantaneous
releases, the INPUFF model should be  utilized, and when heav1er-than-a1r gas
1s considered, OEGAOIS should be employed.   Other models listed 1n Table 2-7
could also be used on a case-by-case basis.

     The dispersion  modeling  plan should  address the  following  for refined
modeling:

     •    Selected model  and rationale.

          Model   applicability,   as   determined  by  the  Superfund  activity
          Involved  and  source   characteristics.    For example,  nonroutlne
          releases during the remedial  action step should be  considered when
          the model 1s selected.

     •    The rural  or  urban character  of the  area,   based  on demographic
          data.

          Wake  and/or  downwash  effects,  Including those   attributable   to
          onslte obstructions.

     •    Particle  deposition taking Into consideration  the  particle  mass-
          size distribution.

          Plume  rise and dispersion  parameters,  Including  Initial  dilution
          parameters.

     •    Model switches (tabulation).

     In  addition,  a  brief  synopsis  of   the model  formulation  should  be
discussed.
                                     2-62

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2.4.8     Estimated Background Concentrations

     Background air concentrations  are  an Integral part  of  many air quality
studies  that  Involve dispersion  modeling.   Such  Information  1s  useful  In
estimating the  cumulative  Impact of  air  toxic  contaminants as  well  as the
Incremental Impact of the  Superfund site  activities.   The major application
for background concentration estimates  Is  to assess conformance with ambient
air quality criteria for ARARs.

     Measurement of  air quality  1n  the vicinity  of  a Superfund  site  could
provide the necessary Information on  existing  background  air quality levels,
providing the following  are met:

     •    The air monitoring  network  was  designed  and  Implemented following
          procedures similar to the  guidelines  provided  1n Section 3.0.

     •    The  network  monitored  several  of   the  site-specific   target
          compounds.

     Background  air  quality  data   could  be   obtained  from  previous  air
monitoring programs conducted  1n  the site vicinity,  as discussed in Section
2.2.5.   It  also could  be obtained  through  the  Implementation  of an air
monitoring program  1n the  vicinity of  the site  as a part  of the Superfund
site activity.

     The modeling plan  should  address the subject  of background air quality
for the Superfund project and delineate the process for estimating background
levels  based  on  existing  data or  proposed  air monitoring.    The  project
objectives and OQOs should serve  as a key factor In assessing the background
levels 1n the vicinity of the site.

2.4.9     Define Dispersion Calculations To Be  Performed

     Once the overall scheme  for  dispersion modeling has been outlined, the
dispersion calculations  to be  performed must be  defined.  -This Includes the
following:
                                     2-63

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     •    Averaging times for calculating concentrations.

               Short term:   hourly and 3-, 8-, and 24-hours.
               Long term:  monthly, seasonal,  annual, or other.

          Dispersion  modeling  scenarios  as   a   function   of   the  Superfund
          activity under consideration.   For  example,  the RI/FS activity inay
          require  modeling  the  no-action scenario  or  scenarios  associated
          with  the  alternative  remedial  actions.     The  remedial   design
          activity may  require modeling  a few  scenarios  associated  with  a
          specific onslte technology.

     •    The results of calculation.

               Tables summarizing receptors that  exhibit high  concentrations
               and sensitive  receptors  with  associated  concentrations,  for
               various averaging times.

               Isopleths of concentrations for the site area.

     The modeling plan should outline  the type of dispersion calculations to
be performed and present results of the calculations.

2.4.10    Document the Modeling Plan

     The modeling  plan  should  be documented  according  to  the  discussion
provided in Sections 2.4.2 through  2.4.8,  utilizing  the outline suggested in
Table 2-9.

2.5  STEP 4 - CONDUCT MODELING

2.5.1     Overview

     Dispersion modeling for  Superfund APA applications  should be conducted
consistent  with  the  modeling  plan   developed   during Step   3.    However,
successful   Implementation  of  the  modeling plan  requires  qualified modelers
and attention to QA/QC factors.  Therefore, the modeling approach illustrated
                                     2-64

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1n Figure 2-9  should  be  applied to Superfund  APAs.   This also  Involves  the
application  of A  Workbook  of Screening  Techniques  for Assessing  Impacts  of
Toxic A1r Pollutants  (U.S.  EPA, 1988) and  Guidelines on A1r  Quality  Models
(U.S.  EPA,   1988),  for   refined   assessments.     Dispersion  modeling
recommendations  presented   1n  other technical  references  may  also   be
applicable 1f specified  1n  the  site-specific modeling  plan.

2.5.2     Staff Qualifications  and  Training

     Dispersion modeling   1s  a  complex   process that  requires  specialized
qualifications and  training.   This  aspect  of  modeling has  been frequently
neglected as  personal  computer (PC)  versions, which are  easy to  use,  have
become prevalent.    However,  1t   1s  also  easy  for  the  novice to  select
Inappropriate modeling options  and/or enter data Incorrectly.   These  errors
can be subtle  1n  nature  and difficult to detect, and they can significantly
affect the validity of the modeling output.  Also, Interpretation of modeling
data requires  a  thorough  understanding of  the theory on which  the  model  1s
based and on  Input  data/model  limitations.   Therefore,  1t  1s Imperative that
a qualified dispersion modeler  thoroughly  familiar  with the modeling process
and the required QC documentation  be  assigned  to provide dispersion modeling
support for Superfund APA applications.

2.5.3     Quality Control

     This section addresses the process of performing dispersion modeling for
a  Superfund  APA  with emphasis  on quality control.   The  modeling  can  be
executed  by  hand  calculation  or  computer  models when  screening dispersion
modeling  (depending on which of the alternative  approaches listed  1n Table 2-
6 1s selected) 1s considered.  It  1s  Implemented with a computer  when refined
dispersion modeling 1s performed.

     The  screening dispersion modeling process Includes the following steps:

     •    Calculate the emission release rate or total release

          Derive the source parameters required  as additional Input
                                     2-65

-------
                           MODELING
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                              2-66

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     •    Define the special parameters required to  estimate  wake  effects or
          negative plume buoyancy

     •    Select the meteorological  data set  or scenario to be modeled

          Define the receptors  for which calculations will  be  performed

     •    Perform the calculations (generally using  computer models)

     •    Obtain conservative concentration estimates

     The refined  dispersion modeling  process  Includes  the  following  basic
tasks:

          Develop the emission  Inventory

     •    Preprocess the meteorological  data

     •    Develop  the  receptor  grid   (this  generally   Involves   refined
          screening modeling as previously discussed)

     •    Run bench mark test cases

          Verify the Input files

     •    Perform model  calculations

     •    Obtain more realistic concentration estimates

     The modeling process  1s delineated 1n Figure 2-10.   The tasks  Involved
1n  these  steps  must be  executed carefully  to minimize  the  likelihood of
errors.  A small error  1n  one  of  the  Input data files will require rerunning
the model, thus  Increasing  the expenses of the project.  Subsequent sections
address  the  refined  dispersion  modeling process.   A  similar but  simpler
discussion applies to the screening  modeling.
                                     2-67

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    Develop
    Receptor
 Grid (Sections
2.2.3 and  2.4.6)
   Preproeess
 Meteorological
 Data (Sections
2.2.4 and  2.4.5)
Develop Emission
    Inventory
 (Sections 2.2.2,
 2.4.3, and 2.4.4)
                                             I
                      Input Into
                      Computer
                         Files
                    Set Up Model
                      Switches
                          JL
                   Run Benchmark
                     Teat  Cases
                     Verify Input
                         Filea
                       Perform
                        Modal
                     Calculations
        a-1O.  TH» Ol«p*r«ion Modeling Proe*a«.
                        2-68

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Develop Emission Inventory

     This task calls for utilizing Input data collected under Step 1 (Collect
and review  Input  Information) (see  Section  2.2) and  developing  an emission
Inventory and  other  source data required  as Input  to  the dispersion model.
The overall  process  of developing  this data  base was  outlined  1n Sections
2.4.3 and 2.4.4.   The emission  Inventory  1s developed using source-specific
formulas, factors,  and procedures described in Volumes  II and  III  of this
Guideline.   Calculated emissions and  related parameters  should  be verified
and tabulated 1n a format similar to that presented 1n Table 2-3.

Preorocess Meteorological  Data

     In most  cases,  meteorological  data compiled  under Step  1 (Collect and
review Input  Information)  (see Section 2.2.4)  must be processed (e.g., using
MPRM or  RAMMET)  prior to  their  use  in the  dispersion calculations,  to make
them compatible with model Input requirements.   Model-specific  meteorological
preprocessing  requirements are  defined 1n  the user's guide  for  each EPA
dispersion model.

     Preprocessing generally  involves  a large volume of data (e.g., 1 year of
data  Includes 8760  hourly va.lues  for  each meteorological  parameter under
consideration).    In  refined, modeling, the  preprocessing is  done  with   a
computerized  preprocessor that  accepts NWS  data  and  generates  a processed
data base compatible with the dispersion modeling code.

     The meteorological data  should  be handled as outlined In  Sections 2.2.4
and  2.4.5  and  as  discussed 1n  reference  material  associated  with each
modeling technique (see Tables 2-7 and 2-8).   The  preprocessed  data should be
rigorously  checked  for  validity  before  their use.    Recommendations  for
meteorological data  validity  checks  are provided 1n  Table  2-10  and  1n  Section
3.0.

Develop Receptor Grid

     A receptor grid should be developed based  on  data collected  under Step  1
(Collect  and review  Input  Information) (see Section  2.2.3)  and the  process
                                     2-69

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                              TABLE 2-10
           SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA*
                         (U.S.  EPA. JUNE 1987)
  Meteorological
     Variable
                Screening Criteria*
Wind Speed
Flag the data If the value:

•  1s less than zero or greater than 25 m/s
•  does not vary by more than 0.1 m/s for 3
   consecutive hours
•  does not vary by more than 0.5 m/s for 12
   consecutive hours
Wind Direction
   1s less than zero or greater than 360 degrees
   does not vary by more than 1 degree for more than
   3 consecutive hours
   does not vary by more than 10 degrees for 18
   consecutive hours
 Temperature
   1s greater than the local record high
   1s less than the local record low
   (The above limits could be applied on a monthly
   basis.)
   1s greater than a 5°C change from the previous
   hour
   does not vary by more than 0.5°C for 12
   consecutive hours
 Temperature
 Difference
   1s greater than 0.1°C/m during the daytime
   1s less than -0.1°C/m during the nighttime
   1s greater than 5.0°C/m or less than -3.0°C/m
a Some criteria may have to be changed for a given location.
                                  2-70

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outlined 1n Section  2.4.6.   The grid  can be rectangular  or circular,  or 1t
can consist of  a  selected number of receptors  located at special  locations.
In  general,  all  three forms  are  utilized  by  most  of   the  refined models
Included 1n  Table  2-8.    The spatial  distribution  of receptors  should be
determined  based  on  factors  discussed 1n Section  2.2.3 and on  site-specific
considerations.  Once  the grid has  been  established and coordinates  assigned
using U.S.  Geologic Survey  (USGS)  maps,  the data  base  can  be put into a
receptor file 1n a format compatible for use by a refined  dispersion model.

     The number of  receptors  may be limited  for  screening modeling  based on
conservative  Input  assumptions  (e.g., worst-case,  short-term meteorological
scenarios  based  on Invariant  wind  conditions).    However,   as  previously
discussed,  a more comprehensive  receptor grid network  1s  generally warranted
for refined screening modeling analyses  to identify high concentration areas.
The  results  from the  refined screening  analyses may  be  used  to  limit  the
calculatlonal  grid   network  to  significant   receptor  locations  for refined
modeling APAs.

     The coordinate of each receptor point should be  verified  as a  routine QC
measure.

Run Benchmark Test Cases

     Two additional  activities have to  be  performed  prior  to  the execution
actual dispersion model runs 1n the case of refined modeling.

     The first  Involves  model  runs with  benchmark  test cases to ensure  that
the  model  performs  as specified.   It  is  recommended  that benchmark  cases
accompanying the  dispersion model  be  utilized and results be  checked against
these cases.

     The second activity  Involves the  setting of  model  switches  1n  accordance
with  the  case under  consideration.     Switches  provide  the  user with  the
program  setting options  pertaining  to  input, dispersion  model, and output.
Examples Include  receptor grid  (rectangular  or  polar), rural or urban  mode,
building wake  and  stack tip  downwash  effects,  printout of  the  50 maximum
concentration  values,  and annual average concentrations.  It  1s Important in

                                     2-71

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this  case to  consider  the  type of  model  output,  based  on the  options
available, to avoid excessive printout without any use for most of 1t.   From
a practical viewpoint, dally and annual concentrations are the most useful 1n
assessing air release  effects  through the APA.   Once  1t has been determined
that the model performs properly  and  the  appropriate switches have been set,
the model 1s ready for execution.

Perform Model Calculations

     Once  the  Input data  files  have been  prepared and  verified,  the model
tested,  and  the  switches   set   properly,  the   actual  dispersion  model
calculations are performed 1n accordance with the modeling plan.

2.6  STEP 5 - SUMMARIZE AND EVALUATE RESULTS

2.6.1.    Overview

     Modeling  results  available  from  Step  4  should  be  summarized  and
evaluated  to  provide  Input to site-specific  APA and the Superfund decision-
making process.  The  recommended  approach (see Figure 2-11) for this step 1s
as follows:

     •    Summarize data.
          Evaluate modeling results.
          Prepare a report.

     Output  of  the dispersion modeling  should  be  summarized  together with
pertinent  source  and meteorological  data  to  serve as a  basis  for data
evaluation.  Calculated high concentrations and  their  locations, coupled with
applicable air  toxics guidelines, should be  used  to evaluate the results of
the  dispersion calculations.   The performance of the dispersion modeling for
existing  sources  could be assessed by  comparing calculated and measured air
concentrations.   The  measured air concentrations are obtained and  evaluated
through  the process outlined 1n Section 2.2.5.

     Results  of the  dispersion  modeling,  together with  Information on the
methodology employed,  should be summarized  1n a  modeling  report.
                                     2-72

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                      INPUT DATA
                         FROM
                        STEP  4
                 SUMMARIZE  DATA

               o  Tabular Data
               o  Graphical Data
     METEOROLOGICAL
         SUMMARIES
AIR CONCENTRATION
    SUMMARIES
                        EVALUATE
                       DISPERSION
                        MODELING
                          DATA
                   o Dtaperalon
                     Qradlente/Patterna
                   o Modeling
                     Concentrations
                   o Supplemental
                     Analyses
                            i
                       INPUT TO
                      SUPERFUND
                  RISK ASSESSMENT/
                   DECISION  MAKING
                       PROCESS
Figure a-11.  Step •  - Summarize and Evaluate Reaulta.
                       2-73

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2.6,2          Summarize  Data

     In general,  the  output  of  computer model  calculations  1s  given 1n  a
tabular form.  These data have to be summarized 1n a form  that 1s useful  for
the specific APA application.   Examples of recommended  tabular data summaries
for air toxics Indicator  constituents  Include

     •    Daily concentrations at  sensitive receptor  locations  Included  1n
          the dispersion  calculations

     •    Maximum long-term (monthly,  seasonal, annual, or other) calculated
          concentrations

     •    Daytime and nighttime  maximum and average concentration estimates
          (for complex  terrain and coastal sites only)

     •    Calculated long-term concentrations at sensitive  receptors

     •    Applicable ambient air  toxics  guidelines

     •    Summaries  of   calculated   versus  measured   (as   available)
          concentrations  for short-  and  long-term averaging times

     •    Source-specific  summaries  for  Superfund  sites  with multiple  air
          release sources.

     A useful presentation of the results 1n graphic form  Is accomplished by
plotting  dispersion factors  or  concentrations  for Indicator constituents.
These  Isopleth  summaries depict  the areas affected by  Superfund  air release
sources.   Figure 2-12 1s  an   example  of a computer-generated, ground-level
Isopleth plot.

     Frequently, It may not be practical  to place air  monitoring  stations at
offslte receptor  locations of  Interest.   However,  It may be necessary to
characterize concentrations at these locations as Input to site-specific risk
assessments.   In  these  cases, dispersion patterns based on modeling results
                                     2-74

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       ESTIMATED ANNUAL      CONC..  UG/M3  (RURAL)
    29.00
         80.00   61.00  62.00  83. OO  84.00  85.00  86.00  87.00
FIGURE  2-12        EXAMPLE OF A COMPUTER GENERATED GROUND LEVEL ISOPLETH PLOT
                               2-75

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can  be  used  to  extrapolate  concentrations  monitored  onslte  to  offslte
locations.   An  Illustration of  modeling  results for  this  application is
provided 1n Figure 2-13.

     Meteorological data summaries should Include the following at a minimum:

          Daytime wind rose (only for coastal  or complex terrain areas)

          Nighttime wind rose (only for coastal  or complex terrain areas)

     •    Summary wind rose

          Summary  of  dispersion  conditions  for  the  sampling  period  (Joint
          frequency  distributions  of  wind  direction  versus  wind   speed
          category  and   stability  class  frequencies   based  on  guidance
          presented 1n Guidelines  on  Air Quality Models (Revised)  (U.S.  EPA,
          July 1986)

          Tabular  summaries  of means and extremes  for  temperature and  other
          pertinent meteorological parameters

     •    Data recovery summaries for all parameters

     Statistical summaries for the meteorological data should be  presented on
a  monthly,  seasonal,  and annual  basis  as  well  as for  the entire  modeling
period.   For  sites  with diurnal wind  patterns  (e.g.,  complex terrain or
coastal  areas),  the modeling should  Include  separate wind roses for daytime
and  nighttime  conditions  and a summary  wind  rose (for  all wind  observations
during the monitoring period).

     Data  recovery Information  should  also  be  presented  to  evaluate  data
representativeness.  A minimum data recovery target should be 90  percent.
                                     2-76

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     CO
ro
    t-I

    S
    g
    t-i
    i
    I
    i
           ATMOSPHERIC DILUTION PATTERN
               NEAREST RECEPTORS

               MONITORING STATIONS

               DILUTION FACTOR ISOPLETHS
               (RATIO OF DOWNWIND CONCENTRATION/FACILITY PROPERTY BOUNDARY CONCENTRATION)

-------
2.6.3     Evaluate Modeling  Results

     Modeling  results   should   be  carefully  evaluated  and  Interpreted  to
provide Input to the Superfund  risk  assessment  process.   Factors that should
be considered during this data  evaluation phase  Include the following:

     •    Modeling concentrations
     •    Source receptor relationship
          Need for supplemental  analyses

     Modeling results should also be  compared to  ARARs considering the above
data  Interpretation factors.    In  addition,   Interpretation of  dispersion
modeling  results  should  account  for  additional  factors  such  as  complex
terrain,  variable  winds,  multiple contaminant  sources, and  Intermittent or
Irregular releases.

Modeling Uncertainties

     The uncertainties  associated with  dispersion modeling results should be
quantified,  If  feasible,  and  evaluated.   Uncertainty  factors  have  been
defined and  discussed  1n Section  2.3.   The UP  values associated  with air
concentration  estimates  should  be  based  on  uncertainties  associated  with
input emission rate values and  meteorological data as well as the  accuracy of
the dispersion model.  This  can be accomplished  as follows:
  UFTQT=      (UFER)Z+(UFMET)Z + (UFDM)Z                        (  2-1)
where
     UFiOT   a    Uncertainty Factor  for  air  concentration  estimate, which
                  accounts for  the accuracy  of  the Input  data as  well  as
                  limitations of the dispersion model.

     UFER    •    Uncertainty Factor associated with emission rate estimates

     UFMET   °    Uncertainty Factor associated with meteorological  data
                                     2-78

-------
     UFQM    =     Uncertainty Factor associated  with  the dispersion model

     The  UFER   values   for  emission   rate   estimates   should   be  based  on
Information  presented  1n Volumes  II  and  III.   Meteorological  monitoring
accuracies  presented  1n  Section  3.0  of  this  volume  should   be  used  to
determine  UFMET  values.   Model-specific UFQM  values  should  be  based  on
Information  presented   in  the  Individual   user's  manuals   and  in  model
performance  studies  that  have  been  conducted  by  the  EPA  and  other
organizations.     In  general,   dispersion  estimates  are  associated  with
accuracies  of     plus   or minus  a  factor  of  2  to  3  for  flat  terrain
applications.  However,  for complex terrain  applications,  modeling estimates
can be inaccurate by more than  an order of magnitude  for some situations.

     The  UF values  account for  the  accuracy  of  modeling   predictions  of
maximum concentrations.    However, field  validation  studies have demonstrated
that  the predicted locations  of maximum concentrations  based  on  modeling
results may  not  correspond  with the location  of the maximum  value  based on
field  measurements.    Therefore,  for  Superfund  APA  applications  1t  1s
necessary  to  define  a  geographic  area of  applicability   for  dispersion
modeling results.

     The geographic area of  applicability 1s defined as the area  in which the
receptor  of Interest   1s located.     It accounts   for limitations  of  the
dispersion  model  to predict the  exact  location of maximum   concentrations.
Therefore,  the maximum  concentrations  that  occur within the  geographic area
of applicability could potentially occur at  the receptor of Interest.

     Example criteria for Identifying  the  geographic  area  of applicability
for  dispersion  modeling results  relevant  to  receptors  of  Interest  are
presented  1n  Table 2-11.   The  geographic area  of  applicability   can  be
specified 1n terms  of a  sector width and a  range of downwind distances.  The
criteria  for the  geographic  area of  applicability  are  a  function  of the
modeling time frame (long term  versus  short  term),  site terrain  (flat versus
complex),  and  -the representativeness  of  the  meteorological  data   (onsite
versus offsite).   The criteria  presented In  Table 2-11 are least restrictive
(I.e.,  smallest  geographic  area of   applicability)  for  long-term modeling
                                     2-79

-------
                                Table 2-11.

 Example Criteria for Identifying the Geographic Area of Applicability for
       Dispersing Modeling Results Relevant to Receptors  of  Interest*
                              Based On Ons1te
                            Meteorological Data
  Based on Offsite
Meteorological Data

Lona Term fz 24 hrs)
• Flat Terrain
• Complex Terrain/
Coastal Locations
ShorMTerni f<24 hrs)
• Flat Terrain
• Complex Terrain/
Impact
Sectors**
R
R ± 22.50

R ± 22.50
R ± 22.50
Downwind
Impact
X
X

X
X ± 0.1X
Impact
Sectors**
R ± 22.50
R ± 22.50

R ± 22.50
R ± 22.50
Downwi nd
Impact
X
X ± 0.
X
X ± 0
X ± 0

1 X

.IX
.2X
    Coastal Regions

*  The geographic area of applicability 1s  defined as the area 1n which the
   receptor of Interest 1s located which accounts for conditions of the
   dispersion model  to predict the exact location of maximum
   concentrations.  Therefore, the maximum  concentration which occurs
   within Its geographic area of applicability could potentially occur at
   the receptor of interest.

** Sector R 1s defined as the 22.5 degree sector 1n which the receptor of
   Interest is located

***   X Is defined as the downwind distance from the source to the receptor
      of Interest.
                                    2-80

-------
results at flat terrain sites with onsite meteorological  data.   The criteria
are most  restrictive  (i.e.,  greatest  geographic  area of  applicability)  for
short-term  modeling  results  at  complex  terrain/control  sites  with  only
offsite meteorological data  available.   Site-specific modeling  factors  may
warrant modifications  to  the  criteria presented in Table  2-11.

Source/Receptor Relationship

     Source/receptor relationships should  be  evaluated  based  on dispersion
patterns  and  gradients.    Isopleth  plots and tabular  summaries  should  be
evaluated to Identify the  most  restrictive  exposure conditions.   For short-
term  modeling   results   (i.e.,  less  than  24  hours)  the  maximum  offsite
concentration values should be  selected considering all  publicly accessible
locations.   The most  restrictive exposure  conditions  based  on short-term
modeling  results  should  be characterized  by  the actual  receptor  locations
with the maximum predicted  concentration.  These maximum short- and long-term
concentration   events  should  be  evaluated   by  calculating   HI   values.
Procedures  for  the calculation of  the  HI  values  have  been  presented  in
Section 2.3

     An example format  is presented  in Table  2-12 for evaluation of HI values
for toxicants and  carcinogens at  receptor locations associated with maximum
concentrations.   As indicated  in Table 2-12,  1t is Important to determine the
relative  impacts  for each   source   type.     This  source-specific  impact
information Is  useful for  the RPM/EPM  to develop a cost-effective strategy
(which  may  Involve technical  and/or  administrative  measures)  to  mitigate
potential exceedances  of health criteria.   For example,  remediation sources
may Involve soil handling  activities  and  an  air  stripper.   Evaluation of HI
values by source type may  indicate  that the greatest  impacts  are associated
with soil handling operations.  Based  on  the Insight, the  RPM  may  decide to
limit  certain   soil  handling  operations   during  adverse  meteorological
conditions.   However, 1t may  be useful to  Identify the relative Impacts of
each of  the  subclasses (e.g., excavations,  haul  roads,  storage piles, etc.)
associated with soil handling  air  emission sources.

     Table 2-12 also facilitates the  evaluations of modeling results relevant
to  constituent-specific  health  criteria.     At   a minimum,   the   modeling
                                    2-81

-------
                                                        Table 2-12.
                     Example Format for  Evaluation of  Hazard Index  for Toxicants and Carcinogens at
                              Receptor Locations Associated with the Maximum Concentrations
                                         Toxicants
Carcinogens

Controlled Sources
• Landfills
• Lagoons
• Contaminated Soil
Surfaces
• Containers
(above-ground)
SUBTOTAL
• Background
TOTAL
Remediation Sources
• Soil Handling
• A1r Stripper
• Incinerator
• In-S1tu Venting
• Solidification/
Stabilization
SUBTOTAL
• Background
TOTAL
Constituent-Specific Hazard Index
Values
A B C D E Etc.







•







Hazard
Index
for Mix















Constituent-Specific Hazard Index
Values
A B C D E Etc.













,

Hazard
Index
for Mix















IN)

00
IN)

-------
                                                        Table 2-12.
                      Exanple Format for Evaluation of Hazard Index for Toxicants and  Carcinogens  at
                               Receptor Locations Associated with the Maxima Concentrations
                                  Toxicants
Carcinogens

Controlled Sources
• Landfills
• Lagoons
• Soil Surfaces
• Containers
(above-ground)
SUBTOTAL
• Background
TOTAL
Constituent-Specific Hazard Index
Values
A B C 0 E Etc.




Hazard
Index
for Mix




Constituent-Specific Hazard Index
Values
A B C 0 E Etc.




Hazard
Index
for Mix




00

-------
constituents  selected based on the  procedure discussed  1n  Section  2.3.2 and
Illustrated  1n  Figure   2-6   should  be   Included   1n  this  evaluation.
Constituent-specific  as well as  total-mix HI  values  should be  computed for
each  source  and  for  all  sources   combined.    A  realistic  assessment  of
potential   Impacts   should  also   Include  combinations  due   to background
concentrations  from  offslte sources.    The  HI  values should  be  computed
separately for toxicants and carcinogens.   These evaluations  can be  used as
Input to the  Superfund  risk  assessment  process.

     An example  format for evaluation  of  HI  values relevant  to  ARARs  Is
presented 1n  Table  2-13.   It 1s recommended that source-specific HI  values as
well as a total-site  HI value be  computed for each  ARAR.

Supplemental  Analyses

     Supplemental  analyses  may be  warranted at complex terrain or  coastal
locations  1n  order  to  apply  dispersion  modeling results  to  Superfund APA
applications.  These supplemental  analyses  may Involve  additional  modeling
(e.g., wind flow field  models,  physical models, specialized mesoscale models)
to characterize local  transport  and/or diffusion conditions.   Frequently 1t
may  be necessary  to  conduct  specialized  field  studies  that may  Involve
Intensive meteorological  monitoring  materials and/or  tracer studies.

     Figures  2-14 and 2-15  Illustrate  an example application of supplemental
analyses.  This Superfund site 1s located on the sloping terrain of a valley
wall.  Available dispersion models could not adequately characterize the very
localized dispersion conditions.   However, receptors were located at the site
perimeter, and 1t was  necessary  to  characterize potential   Impacts associated
with soil handling operations  at the onslte  landfill.   Smoke and  SFe tracer
studies  were  used   to  define  transport  paths  for  typical   drainage  flow
conditions.  These results  are summarized 1n Figure  2-14.   Results from the
tracer  studies were  also used to  develop a  site-specific  dispersion model.
These results are summarized in Figure 2-15.

     Supplemental analyses  can be  expensive  and result  1n project schedule
delays.    Therefore,  these   analyses  are  generally  only  warranted  1f
                                     2-84

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                               TABLE 2-13
EXAMPLE FORMAT FOR EVALUATION OF HAZARD  INDEX VALUES RELEVANT TO ARARs AT
            LOCATIONS ASSOCIATED WITH MAXIMUM CONCENTRATIONS

Uncontrolled Sources
• Landfills
• Lagoons
• Contaminated Soil
Surfaces
• Containers (above-
ground)
SUBTOTAL
• Background
TOTAL

Remediation Sources
• Soil Handling
• A1r Stripper
• Incinerator
• In-SItu Venting
• Solidification/
Stabl1zat1on
SUBTOTAL
• Background
TOTAL

Controlled Sources
• Landfills
• Lagoons
• Soil Surfaces
• Containers (above-
ground)
SUBTOTAL
• Background
TOTAL
ARAR-Spec1f1c Hazard Index Values
a



























b



























c



























d



























e



























etc.























•



                                  2-85

-------
     Wm '*
     g
CD

                                                     Drainage MUM Saokc Test Results

-------
ro

CD
   7*
   H*
   Ul
S
>—i
*
                SPiOHC ATMOSPHERIC DISPERSION
                                                     FACTOR
                                                            DILUTION
                                                             FACTOR
                            DILUTIO
ON FACT

-------
unacceptable  offsite  air  pathway   Impacts   have   been   predicted   based  on
application of standard dispersion models and modeling procedures.

2.6.4     Prepare A Report

     A report summarizing  the  results of the dispersion calculations  should
be prepared.   It  should Include the elements  of  the modeling plan  discussed
In Section 2.4.  These elements basically outline the overall methodology  for
the modeling.  The following  Is a recommended outline for the report:

I    Introduction

II   Methodology

          Constituents To Be  Modeled
          Emission Inventory
          Receptor Grid
          Detailed Modeling Methodology
          Estimated Background  Concentrations

III  Modeling Results

          Short- and Long-Term Concentrations
          Areas of Potential  Impact
          Comparison with Applicable A1r Toxics Guidelines

IV   References

V    Appendices

          Meteorological Data
          Emission Inventory
          Model Testing
          Detailed Modeling Printout
                                     2-88

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     The report  should  Include  a  sufficient  amount  of  explanation  of  the
methodology and  results.   Figures  such  as  Isopleths  of  concentrations  are
highly recommended.

2.7  EXAMPLE APPLICATION

     A  screening  assessment   (based  on   emission/dispersion  modeling)
commensurate with  Volume  I  recommendations  was  conducted  to  characterize
hazardous  air  constituents  being released  from an  Inactive wood  treatment
facility that  had  been placed  on  the NPL.    Evaluation  of these  screening
results Indicated that 1t was  necessary  to  conduct a dispersion  modeling to
more accurately quantify air emissions from the site to  support  preparation
of an RI/FS.

Collect and Review  Information

     The site  1s  an Inactive  12-acre  wood   treatment  facility  located  1n  a
flat  Inland   area  of  the   southeast.     At  one  time,  creosote   and
pentachlorophenol  were used  as  wood  preservatives; heavy metal  salts  were
also used.   The creosote and pentachlorophenol were disposed of  1n  a  surface
Impoundment.   Past waste disposal  practices Included treatment  and disposal
of the metal salts  1n a surface Impoundment  and disposal  of contaminated wood
shavings 1n waste piles.  The constituents of concern 1n the facility's waste
stream  Include phenols, cresols, and polycycllc  aromatic  hydrocarbons (PAHs)
1n  the  creosote;   d1benzod1ox1ns   and  dlbenzofurans  as  contaminants  1n
pentachlorophenol;  and  partlculate  heavy metals.   The   potential  emission
sources (Figure 2-16) Include the container  storage facility for creosote and
pentachlorophenol,  the wood treatment and product  storage areas,  the  surface
Impoundment for   the  creosote  and  pentachlorophenol   wastes,  and   the
contaminated  soil   area,  which previously  contained   both   the  surface
Impoundment for treating the metal salts  and the wood  shavings  storage area.
Seepage from these waste management units has  resulted  1n documented  ground-
water and surface water contamination.

     The   area surrounding   the  facility  has  experienced   substantial
development over the years.   A shopping center 1s now adjacent to the eastern
                                     2-89

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           INACTIVE SURFACE
           IMPOUNDMENT ANQ
           CONTAMINATED
           WOOD SHAVINGS
           STORAGE APEA
          AERATED
          SURFACE
          IMPOUNDMENT
             OFFICE Q
       TREATMENT
       AND PRODUCT
       STORAGE AREAS
                  CONTAINER
                  STORAGE
                  FACILITY
                      •4 h-
                       GATE
                                             PREVAILING
                                             WIND
                                             OIPECTON
FIGURE 2-16
EXAMPLE SITE PLAN FOR AIR DISPERSION MODELING
                               2-90

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site perimeter.  This  development  has significantly  Increased  the number of
potential  receptors  of  air releases of hazardous constituents.

     To perform  an  adequate  air  dispersion  modeling,  the composition of
wastes handled 1n each  waste management unit was first determined  to  Identify
which constituents were likely  to  be present 1n the  air releases.   Existing
water  quality data  Indicated  contamination  of  groundwater  with   cresols,
phenol, and PAHs, and of  surface water with phenols, benzene,  chlorobenzene,
and  ethylbenzene.    A field   sampling  program  was  developed   to  further
characterize the facility's waste  stream.   Wastewater samples were collected
from the  aerated  surface  Impoundment, and  soil samples  were collected  from
the  heavy  metal  salt  waste treatment/disposal  area.    Analytical data  from
this sampling  effort confirmed the  presence of the  constituents previously
Identified.  Additional constituents detected Included toluene  and xylenes 1n
surface Impoundment  wastes, and arsenic, copper,  chromium,  and  zinc 1n the
treatment/disposal  area.

Select Modeling Sophistication Level

     A  screening  air  dispersion  modeling  was performed as  a part of the
planning  stage  for  the project.   It  addressed  a  few receptors  at  the  site
perimeter.  The  increase  1n development 1n  the vicinity of the site and the
associated  Increase in the  number  of  potential  receptors  that  could be
exposed to air toxics  releases from  the  site  required the use  of refined
dispersion modeling 1n support of the RI/FS activities.

     It was determined  that the ISC dispersion model  1s the preferred  model
for  this applications because

     •    The  sources   Involved  resemble Industrial  sources similar to  the
          ones the model was developed for.

          The  topography   1s  gently  rolling  and  no   major  topographical
          obstruction exist.

          The  ISC dispersion model was employed successfully for  a Superfund
           site similar  to the one under consideration.
                                     2-91

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Develop Modeling  Plan

     Based on their Individual emission potentials  (as  determined  from  waste
analyses  and  confirmatory  emission  rate   modeling)  and  potential   for
presenting   health  and  environmental  hazards,  the   following  target
constituents  were selected for use  1n the dispersion modeling:

     •     Volat1le/sem1volat1le constituents

               Toluene
               Benzene
               Total phenols
               Pentachlorophenol
               Polycyclic aromatic  hydrocarbons
               Cresols

     •     Part1culate constituents

               Arsenic
               Copper
               Chromium
               Z1nc

     The target constituents  list  was  then  evaluated 1n terms  of  prevalence
of constituents'  1n each of  the  four sources  and the  Information available
about the activities Involved with  each source  (see  Table 2-14).

     Emission predictive equations  were Identified  using Volume II Technical
Protocol and- Procedures  for Developing Baseline  A1r Emission  Estimates,  of
the Procedures for Conducting A1r Pathway Analysis for Suoerfund Application.
for the sources Involved.  This Included

          Predictive lagoon  equations  for  the  Inactive surface  Impoundment
          and the  aerated  surface  Impoundment  for organic*, and  predictive
          fugitive dust  equations for Inorganics
                                    2-92

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                          TABLE 2-14
TARGET CONSTITUENTS MODELED FOR EACH OF THE SOURCES AT THE SITE
Indicator
Constituents
Organ 1cs - gases
Toluene
Benzene
Total phenols
Pentaoch 1 orophenol
PAHs
Cresols
Inorganics -
part 1cu late
Arsenic
Copper
Chromium
Z1nc
Source
Inactive
Surface
Impoudnment

X
X
X
X
X
X

X
X
X
X
Aerated
Surface
Impoundment

X
X
X
X
X
X





Treatment
and Product
Storage
Areas

X
X
X
X
X
X

X
X
X
X
Container
Storage
Facility




X

X

X



                              2-93

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     •    Predictive  closed landfill equations for  the  treatment and product
          storage  areas and  the container  storage facility,  and predictive
          fugitive dust equations for Inorganics

     Onslte meteorological  monitoring from a 10-meter tower provided 3 months
of  data.    These   data   were  used  to   evaluate  the  applicability  of
meteorological  data available from  an NWS station located about 25 kilometers
southeast of the site.   The evaluation of wind data showed that

          Offsite  meteorological data correlate  reasonably  with  the  onslte
          data  for the same time  period.   Wind  direction data  for off site
          areas show the same pattern as those for onslte areas: an apparent
          small shift of about 10 to  15  degrees.   The frequency distribution
          of wind  speed and  direction  by  stability  1s  within  about  20-30
          percent.
     •    No major topographical features.or water bodies exist between the
          NWS station and  the site.

     It  was decided  to use  5 years  of  meteorological  data from the NWS
station.  This Included both surface and upper air data.

     Considering prevailing  wind  directions,  source  characteristics (ground
level  releases),  population  distribution  1n  the  site vicinity,  and  other
sensitive receptor locations, 1t was decided to set up a grid as follows:

          Program adjust all stack  heights for downwash • No. (=1)

     For modeling  purposes,  concentrations were averaged every 24 hours and
annually.

     Background concentrations for the Indicator compounds were obtained from
a 1-month perimeter monitoring program conducted at the site.   The  background
concentrations were obtained from upwind stations utilizing the onslte data.
                                     2-94

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Conduct Modeling

     The emission Inventory for  the Indicator compounds  was developed based
on the methodology outlined 1n the  modeling plan.   Data  were Input Into the
ISC  dispersion  model.    Meteorological  data  from the NWS  station  were
preprocessed  to generate  hourly data  used  by  the  ISC dispersion  model.
Receptor coordinates  based  on  the  receptor  developed were Input  Into the
model.

     All Input data wwere checked and  verified before  the files were linked
to the model.  A test run was  performed  to verify that the model performed as
specified.

     Dispersion  calculations  were   performed  for  each  of  the  Indicator
constituents, and computer printout  were obtained.   Individual runs were made
for the various Indicator constituents.

Summarize and Evaluate Results

     Results of the calculations were checked to ensure  that no errors were
made with the Input data.  Three hand calculations were made to determine the
arsenic  concentration  at  a  selected  receptor  to  verify  that  the model
calculations  are  correct.   Ground-level  concentrations  were summarized for
each  Indicator constituent by considering the highest and second highest 24-
hour concentrations and 24-hour  concentrations at sensitive  receptors.

     Isopleths  of  annual  concentrations   were   plotted   for the   Indicator
compounds 1n a format similar to the one shown 1n Figure 2-10.

Prepare a Report

     A report summarizing the results of  the dispersion  calculations  and the
detailed methodology  was prepared.   The calculations were  based on readings
obtained at  receptors arranged  1n  a rectangular  grid (see  Figure 2-17) with
Intervals  of 100  meters for the  area close to  the site  and on  the site
perimeter;  200  meters  for the  area  from  the  site perimeter  to  about  1
kilometer from  the center of  the site;  500-meters for the,area between  1  and
                                     2-95

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                                                                  N
                                                                  i1
              •     •
•     •     •    •    •     •
         •    •    •      •     •    •
                 •    •
                                                                 prevailing
                                                                    Mind
                                                                 direction
                                      •     •
site
area
                                      •    •
FIGURE 2-17           RECEPTOR GRID CLOSE THE SITE


                              2-96

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2  kilometers  from the  center  of  the  site;  and  1  kilometer  for  the area
between 2 and  5 kilometers from the center of  the site.

     This receptor  distribution was considered adequate  to  cover offsite
publicly accessible  locations and sensitive environmental receptors.

     In the latter case,  1t was  determined that most of the development took
place up to about 2  kilometers from of the site and mainly to the east.

     The model  selected  was the ISC dispersion model.  It was considered most
suitable for this application.  Both  the short-  and long-term calculations
were performed.  Key model switches Included

     •    Calculate  concentration (=1)

     •    Discrete receptor system  - rectangular (=1)

     •    Terrain elevations are read -  no (=0)

     •    Compute average concentrations  for  24 hours - yes  (=1);  for other
          averaging  times - no (=0)

     •    Print highest  second highest tables  - yes  (=1); maximum 50 tables -
          yes  (=1)

     •    Rural-urban option - rural (=1)

     •    Wind  profile exponent values - default (-1)

     •    Vertical potential temperature gradient values - default (=1)

     •    Program calculates final  plume rise  only - no (=2)
                                     2-97

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                                SECTION  3
                 AIR CONCENTRATION MONITORING  PROCEDURES
3.1       OVERVIEW

     A1r  concentration  monitoring  is  an  air  pathway  analysis  (APA)
approach that provides direct measurements of air contamination levels for
receptor  locations  of  interest.    However,  this  approach is  limited to
existing  sources.    Also,  monitoring   methods  with  detection  levels
commensurate  with   health   criteria  may   not  be   available   for  all
contaminants  of  interest.    This  section  provides  procedures   for  the
selection and application of air monitoring approaches for Superfund APAs.

     Superfund activity and source-specific recommendations concerning air
monitoring  applications  have   been presented   in  Volume  I.    A cross-
reference to  these  recommendations  and  a summary  of potential   Superfund
air monitoring applications are presented in Table  3-1.  A review of Table
3-1  indicates that  air monitoring  applications are  directly  related to
specific  Superfund  activities.   Therefore, the technical  information and
recommendations  1n  this section are frequently presented  on a  Superfund
activity-specific basis.

     The  procedures  for air  monitoring APAs  presented in this section are
based on  a five-step process (illustrated in Figure 3-1):

          Step 1 - Collect and review input Information
          Step 2 - Select monitoring sophistication level
                                    3-1

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                                                                               TABLE  3-1

                                                                SUMMARY OF AIR MONITORING APPLICATIONS
                   Source Classification
                                                        APA Recommendations
                                           Superfund Activities
                                       Atr Monitoring Applications
            Uncontrolled source
Characterize baseline air
concentrations
RI/FS -  Screening/Refined
         Screening APA
Preliminary baseline air
quality data and Information on
emissions
Atr quality data In support of
the design of a refined air
monitoring program to support
the RI/FS (I.e.. preparation of
site-specific Mork Plan and
Field Sampling and Analysis
Plan)
             Uncontrolled  source
Characterize baseline air
concentration
                                                                                     RI/FS  -  Refined APA
i
IN)
                                       Comprehensive baseline air
                                       quality for onslte. perimeter.
                                       and offslte.
                                       Data are used as risk
                                       assessment Input for the no-
                                       action alternative
                                       Data are used In evaluating
                                       remedial alternative actions
             Remediation source
Characterize air concentration
during remedial/removal activities
Remedial design (pilot field
studies)
Mork area, perimeter, and
offstte air monitoring program
In support of pilot field
studies
Data are used to assess worker
exposures and estimate the
effect on the public and the
environment during the remedial
action

-------
                                                                  TABLE 3-1

                                             SUMMARY OF AIR MONITORIMG APPLICATIONS (Continued)
       Source Classification
        APA Recommendations
       Superfund Activities
 Air Monitoring Applications
Remediation source
Characterize air concentrations
during rewdlal/removal activities
Remedial actions I fun-scale
operations)
worn area, perimeter, ana
offsite air Monitoring program
In support of cleanup
activities
Data are used to protect
workers, the public, and the
environment under routine and
nonrouttne air releases
Controlled source
Confirm controlled source air
concentrations
Operation and maintenance
(post-remedial activities)
Perimeter and offslte program
to evaluate the performance of
the remedial action
Data are used to verify the
effectiveness of the remedial
action In protecting public
health and the environment

-------
•f»Xat*0«l A«t.M
A^A QuMfMifle>o)
 V0l«. Ill * IV
                     COLLECT AND REVIEW
                         INFORMATION

                    o   Source Data
                    o   Receptor Data
                    o   Environmental
                        Characteristics
 Available
Monitoring/
 Modeling
   Data
                      SELECT  MONITORING
                    SOPHISTICATION  LEVEL

                    o   Screening
                    o   Refined
     EPAXNIOSM
      Monitoring
      Guidelines
                               1
MevlowXNPM
  Approval
                    CONDUCT  MONITORING

                    e   Routine  Operation
                    o   Quality Control
                    o   Reid  Documentation
                                                   INPUT TO
                                                  PA MMBDUU
                                                   MMOVAI.
Figure 3-1.  auperfund Air Pathway Analysea Air Monitoring Protocol.
                           3-4

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     •    Step 3 - Develop monitoring plan
     •    Step 4 - Conduct monitoring
     •    Step 5 - Summarize and evaluate results

The following 1s a brief discussion of each of these steps.

     Step  1  -  Collect  and  Review  Input  Information—This  initial  step
addresses  the  process  of collecting  and compiling  existing. Information
pertinent to the air monitoring  program  based on a literature survey.  It
includes  obtaining  available  source, receptor,  and  environmental  data.
Once the existing data  have  been collected,  compi.led, and evaluated, data
gaps can be defined and a coherent air monitoring plan developed based on
the site-specific requirements.

     Step 2  -  Select  Monitoring  Sophistication  Level—This  step Involves
the  selection  of  the  air  monitoring  sophistication  level  considering
screening, refined  screening,  and refined  monitoring techniques.   This
selection  process depends  on  program  objectives  as  well   as  available
resource  and  technical   constraints.   Technical  aspects that  should  be
considered include the availability of appropriate monitoring and analysis
techniques  for  the  Superfund  11st  of  toxic  constituents.   Monitoring
approaches should  be  evaluated  considering  constituent-specific factors,
Including  detection  limits,  performance   criteria  (e.g.,  precision,
accuracy), and advantages and disadvantages of alternative methods.

     Step 3  -  Develop Monitoring  Plan—This  step involves preparation of
an  air  monitoring plan.   Elements that  should  be addressed  in  the plan
Include (a) selection of monitoring constituents, (b)  specification of  the
meteorological  monitoring program,  (c)  specification of  the monitoring
network  design  (I.e.,  number  and  location of  monitoring  sites,   probe
siting  criteria,  sampling and analysis  methods,  and  program duration  and
frequency  of   monitoring),   (d)   development  of  project  data  quality
objectives  (DQOs)  and  sampling  and  analysis quality  assurance  (QA)  and
quality  control  (QC)  procedures,  and   (e)  documentation  of  the   air
monitoring plan.
                                    3-5

-------
     Step  4  -  Conduct  Monitoring—This   step   Involves  the  day-to-day
activities of  conducting  an air  monitoring program at  a  Superfund site.
It   Includes   the   following:    (a)   routine  equipment   operation  and
maintenance,   (b)  sampling  calibrations   and  checks,  (c) audits,  (d)
handling  of   samples,   (e)   field  documentation,   (f)  maintenance   of
laboratory data  and  records  (including  chain-of-custody forms),  and  (g)
other  QA/QC  procedures   necessary  to  ensure  a  successful  monitoring
program.

     Step 5 - Summarize  and Evaluate Results—This step  Involves reviewing
data  and evaluating  air  monitoring  results  for  validity.   Additional
components   of   this   step    should    include    (a)    data   processing,
(b) preparation  of  statistical  summaries,  (c)  comparison  of  upwind  and
downwind  concentration  results,  and  (d)   concentration   mapping,   if
possible.  Estimates  of  data uncertainties based on Instrument limitations
and analytical technique Inaccuracies should  also  be  obtained and used to
qualify air monitoring results.

     The following subsections  present  an expanded discussion  of  each of
these steps.

3.2       STEP 1  - COLLECT  AND  REVIEW  INPUT INFORMATION

3.2.1     Overview

     The first step  1n the design and Implementation  of an effective air
quality monitoring program 1s  the compilation and evaluation of available
Information  via   a  literature  search.    A  summary  of  this process  is
presented In Figure 3-2.
                                    3-6

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     SOURCE DATA

o Sit* Layout Map
o Sourea Specifications
o Contaminants  List
o Toxlclty Factors
o Offslta Sources
    RECEPTOR DATA

o Population Distribution
o Sanaltlva Racaptors
o Slta Work Zonaa
o Local  Land Uaa
ENVIRONMENTAL  DATA

o Dlaparslon  Data
o Climatology
o Topography
o Soil and Vagatatlon
   PREVIOUS APA DATA

o Motoorologleol
  Monitoring Dots
o Bmloolon Rato Modallngx
  Monitoring
o Dlaporslon Modeling
o Air Monitoring
o ARAR Summary
                        COLLECT
                       AVAILABLE
                      INFORMATION
                         COMPILE
                            AND
                        EVALUATE
                      INFORMATION
                       (TABLE  3-2)
                           INPUT
                             TO

                 STEP 2 - Salaot Monitoring
                     Sophlatlcatlon Laval

                            AND

                STEP 3  - Davalop Monitoring
                            Plan
   nguro 3-a.  Stop 1 - Colloot and Rovtow Input Information.
                         3-7

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     The  following  information,  at  a  minimum,  should  be  collected and
reviewed to support air monitoring program design:

     •    Source data
     •    Receptor data
     •    Environmental data
          Previous APA data

     Most  of  the  site-specific  information  required  for  Step   1   is
available from  the  Superfund  remedial  project manager/enforcement project
manager  (RPM/EPM).   The quality  of  available  Information  will  depend  on
the nature  and  extent of the previously  performed  studies.  For example,
information    available    at     the    initiation    of    the   Remedial
Investigation/Feasibility   Study   (RI/FS)  may   be   limited  in  nature.
However,  information  available  for the implementation of remedial actions
could be  very thorough depending  on  the level of effort and extent  of  the
RI/FS.   In  any  event, available  information  and  data should be  evaluated
for the following factors:

          Technical soundness of methodologies employed

          Completeness  and  quality   of   the  data,   Including   detection
          limits, precision, and  accuracy

      •    Quality  assurance/quality  control  1n support of  the information
          gathered

          Compatibility and applicability  of  the  data

          Data  gaps
                                     3-8

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     Supplemental   information  gathered  through  a  literature  search  is
available from records and documents from sources such as the following:

          U.S. Environmental  Protection Agency (EPA)
     •    State and local  agencies
     •    Contractor studies
          National  Weather Service (NWS)
     •    Other Federal  Government offices

     The information collected during  Step  1  should be documented using a
form similar  to the example  presented in Table  3-2.   This form should be
used to identify and evaluate available data.  In addition, copies of data
summaries should be attached to the form to provide a  convenient, complete
documentation package.

     The following subsections provide a further discussion of the various
types of data that should be collected during Step 1.

3.2.2     Source Data

     Site-specific   information   on   the  nature   and   extent   of   the
contamination  is useful  1n estimating  the magnitude of air emissions from
each   of   the  source  areas   and  in   defining   the  primary  emission
constituents.   The data  should  be available from  the Superfund RPM/EPM.
Specific  information  that should be collected  and  evaluated  Includes  the
following:

          Specific source areas at the site and  their  estimated  locations,
          configuration,  and  dimensions  based  on  Information about past
          contamination.    (Example source  areas  are  lagoons, drainage
          ditches,  landfills, contaminated  soil  surfaces, drums, tank  and
          container areas, and structures within processing facilities.)

          Constituents  associated  with  each   source  area,  grouped  as
          organ1cs  (volatiles,  semlvolatlles,  base neutrals, pesticides.
                                    3-9

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                                      TABLE 3-2.  EXAMPLE - SUPERFUND AIR MONITORING  PROGRAM INPUT INFORMATION FORM
Data Type
Source Data
• Site Layout Map
• Source Specifications
• Conttalnants List
• Contaminant Toxlclty
Factors
• Offslte Sources
Receptor Data
• Population Distribution
Map
• Identification of
Sensitive Receptors
• Site Work Zones Map
• Local Land Use
Environmental Data
• Dispersion Data
- Mind Direct Ion/Mind
Speed
- Atmospheric Stability
Data Obtained
(Yes or No)









(Attachment
No.)









Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)









Completeness
and Quality
of Data
Acceptable
(Ves or No)









QA/QC
Appropriate
(Ves or No)









Data
Relevant for
this
Application
(Ves or Ho)









Data Gaps
Significant
(Ves or No)









Comments









I
t—•
o

-------
TABLE 3-2.  EXAMPLE - SUPERFUND AIR MONITORING PROGRAM INPUT INFORMATION FORM (Continued)
Data Type
Lnvlroranenta.1 Data (Cont'd)
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Maps
- Site
- Local Area
• Soil and Vegetation
Previous APA Data
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data Obtained
(Yes or No)









(Attachment
No.)









Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)









Completeness
and Quality
of Data
Acceptable
(Ves or No)









QA/QC
Appropriate
(Yes or No)









Data
Relevant for
this
Application
(Yes or No)









Data Gaps
Significant
(Yes or No)









Comments










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          PCBs)  and  Inorganics  (metals and  other toxic  compounds [e.g.,
          H2S, HCN1).

          Toxldty factors Important  in  evaluating  the  potential  risk to
          human  health  and the environment and accounted for 1n the design
          and Implementation  of  air  monitoring programs.

     •    Identification  and  description of offsite air emission sources.

3.2.3     Receptor Data

     Receptor data, when  coupled  with source data,  can  provide the basis
for  a  cost-effective  air   monitoring  program  design  for  a  Superfund
project.   Receptor  information that  should be  collected  and evaluated
includes the following:

     •    Results   of  air   dispersion  modeling  showing   locations  of
          calculated   high-ground-level   concentrations   of   air   toxics
          constituents  emitted from  the site  and  from other nearby  sources

     •    Upwind and  downwind receptor locations  based on prevailing wind
          conditions  at the site

     •    Population  distribution  by  22.5-degree  sectors  1n  1- to  2-
          kllometer increments  for  a distance of  10  kilometers  from the
          site

     •    Sensitive  receptors  within  10  kilometers  of  the  site  and
          Individual  residences and buildings within 1 to 2 kilometers of
          the site

          Site work zones as  identified in the Health and Safety Plan

          Local  land  use  characterization (e.g.,  residential, commercial)
          within 10 kilometers of  the site
                                   3-12

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     Sensitive receptor locations Include schools and hospitals associated
with sensitive population  segments,  as well  as  locations where sensitive
environmental  flora  and  fauna  exist,  Including  parks, monuments,  and
forests.

3.2.4     Environmental Characteristics

     Existing Information on environmental  characteristics pertinent to a
Superfund site 1s a necessary  component  for defining air pathway exposure
potential.   Environmental  characteristics data  that  should  be considered
Include the following:

          Dispersion characterization  data  Including wind direction/speed
          and atmospheric stability summaries

          CUmatologlcal data-  representative of  the  site area. Including
          wind, precipitation,  temperature,  and humidity conditions

          Topographic  features  and water bodies at the site and vicinity

          Soil and vegetation characteristics of the site and vicinity

          Other  environmental   settings  that  could  affect  the  number,
          location,  and  type   of   air  monitoring  stations,  Including
          sensitive environmental species

     Existing  representative  dispersion  and c11matolog1cal  data  will  be
useful  1n evaluating the numbers and locations of air monitoring stations.
Wind  data  can  be used  for  evaluating  candidate  upwind  and  downwind
locations for air monitoring.    Wind data,  atmospheric  stability, ambient
temperature,  and  mixing height data can  be  used, coupled with one of  the
air  dispersion  models  described  In   Section  2,   to  provide estimated
calculated concentrations for the constituents of Interest at  locations  of
maximum  Impact.    Temperature  and   humidity   data  could  provide   some
                                    3-13

-------
information  on  the  potential  for  volatilization.    Precipitation  data
provide some Insight  on the potential for wind erosion of participates.

     Topographic features and water bodies could affect the dispersion and
transport of airborne  air  toxic constituents.   It is therefore  Important
to  understand  local   wind   flows  and  to  identify areas  with topography
and/or water bodies  that could influence  the  dispersion  and transport of
constituents  released  from  the   site.     For  example,   a   site  located
downslope of an elevated  terrain  feature could be  affected by  nighttime
downslope drainage flows.   Topographic features should also  be considered
in siting air monitoring stations to avoid natural obstructions.

     Large water bodies  could  affect atmospheric  stability conditions and
the dispersion  of  air contaminants.   In  general,  large water bodies tend
to  increase  the  stability  of the atmosphere  1n the air layer adjacent to
the water, thus reducing the dispersion of air contaminants.

     Soil  characteristics   and  conditions can  affect  air emissions from
Superfund sites and the  wind erosion of  contaminated  surface  soils.   It is
therefore  important  to  understand  soil  conditions  such   as   porosity,
particle size distribution, soil type, and source  data.

     Vegetation, Including shrubs  and  trees,  can  be a factor 1n  siting an
air  monitoring  station  due to flow obstructions  and  accessibility.   In
addition,  vegetation  could affect  air releases because of the  Increase in
soil  coverage  and  air flow because  of the Increase  1n surface  roughness.
It  is therefore Important  to  obtain pertinent Information for use  in  the
design of the air monitoring network.

      Similarly.  1t  1s  Important  to  obtain  and  evaluate  data  on  other
environmental settings to  ensure that  a  balance 1s maintained 1n selecting
the numbers  and  locations  of air monitoring stations.
                                    3-14

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3.2.5     Previous APA Data

     The Superfund APA  recommendations  presented 1n  Volume  I specify the
conduct of emission rate modeling/monitoring  and dispersion modeling as a
prerequisite to  an air monitoring  study.   Therefore,  the following data
should  be  available  from  previous  APAs  and  should  be collected  and
reviewed:

     •    Onsite meteorological  monitoring data

     •    Emission rate modeling data

     •    Emission rate monitoring data

     •    Dispersion modeling  data

     •    A1r monitoring data

     •    Applicable  or  relevant  and  appropriate   requirements   (ARAR)
          summaries that Identify air toxic exposure criteria

     These  APA  data  are  significant  Input   to development  of  a site-
specific  air monitoring program.    Therefore,  site-  and source-specific
APAs  to estimate  emission  rates and  air concentrations  (via  dispersion
modeling)  should  be  conducted  to  provide  these   Inputs  pursuant  to
recommendations  specified   1n  Volume  I.    Procedures  for characterizing
baseline air emissions  from Superfund sources are presented in  Volume II,
and procedures  for characterizing  air emissions from  remedial actions are
available  1n  Volume  III.    Procedures  for  the  conduct of   dispersion
modeling  studies to  support  Superfund  APAs  are presented  in  Volume IV,
Section  2.   A discussion of  Federal  ARARs and  sources of Information on
state ARARs 1s provided in Volume I.

     Previous  air quality  data  available  for the  site area that  address
air concentrations of constituents  known  to  exist at  the  site can  provide
                                   3-15

-------
Insight  on  the  existing  levels  of air  toxic constituents  of  Interest.
Compound-specific Information will  be useful  in  assessing what  Indicator
compounds   should   be  monitored  and   what  monitoring   and   analysis
methodologies should be employed.

     Existing  air  quality  data  should  be  evaluated   for   acceptable
quantity,  quality,  and  representativeness  before  use.    Factors  to be
accounted for 1n these evaluations include

          Monitoring  and   analysis  techniques  employed   during  the  air
          monitoring  program.     These  include  the  type  of   techniques
          (screening,   refined   screening,   or    refined  monitoring),
          associated  detection   limits,  accuracy,  and precision  for the
          constituents monitored.

          Mix and  number  of compounds monitored and  analyzed  for.   This
          information 1s Important to  determine the degree of Interference
          between the compounds  Involved.   Such a  matter  often  limits the
          usefulness   of    nonspecific   compound    screening    analysis
          procedures,  since the response  from background compounds may
          overwhelm any response because of small  levels  of  the compounds
          of Interest.

      •    Records   about    equipment   performance,   maintenance,   and
          calibration.

          Records of audits performed  to evaluate program  quality.

      •    Detailed  description  of the monitoring station  setting to allow
          for an evaluation of  the  station  siting.   Consideration is given
          to siting criteria such as  proper sample Intake exposure, proper
          height above  ground,  and  avoidance of man-made  and  natural
          obstructions  that could  affect or  alter the air flow  near the
           sampler  Intake.
                                    3-16

-------
     Existing air dispersion modeling for the site area could be useful  in
evaluating locations for  ambient air monitoring  stations.   The objective
of the  dispersion modeling,  together  with  the input data,  the modeling
technique,  and  assumptions   about  the  source  air  releases,   should   be
evaluated to determine the applicability and utility of the results of the
dispersion calculations.  Coupled with  measured air quality data, results
of air dispersion modeling offer an objective means for siting air quality
monitoring stations at  locations of maximum impact.   Data available from
air  dispersion  calculations  could  be  used  as  input  into  the  risk
assessment,  which  could   in  turn   be   used  in   selecting  locations   of
sensitive receptors.   Procedures for  the conduct  of  dispersion modeling
are presented in Section 2.

3.3       STEP 2 - SELECT  MONITORING SOPHISTICATION LEVEL

3.3.1     Overview

     The  selection of  air  monitoring  sophistication  levels,  including
associated  sampling and  analytical  methods,  is  the  cornerstone   of  a
successful air monitoring program.  A summary of this  process is presented
in Figure  3-3.   The appropriate monitoring  sophistication level for each
Superfund project application depends on the following factors:

     •    Source-specific  APA recommendations (presented 1n Volume I)

          Input data from Step 1 (Table 3-2)

          Technical air monitoring objectives (Table 3-3)

     •    Overall project objectives and activity-specific air  monitoring
          applications (Table 3-3)

          Legal and liability aspects of the Superfund project

     •    Pragmatic aspects of the program
                                   3-17

-------
 SOURCE-SPECIFIC
         APA
RECOMMENDATIONS

      (Volume I)
  STEP  1  •  INPUT
        DATA

     (Table 3-2)
           AIR  MONITORING
             OBJECTIVES

              (Table 3-3)
             AVAILABILITY
           OF APPROPRIATE
              MONITORING
             TECHNIQUES

         (Tables  3-4 and 3-5)
                     MONITORING
                  SOPHISTICATION
                        LEVEL

                     (Figure  3-4)
              STEP 3 -
 INPUT
  TO

Dovolop Monitoring
  Plan
  Rguro 3-3.  Stop Z - Soloot Monitoring Sophistication Lovol.
                         3-18

-------
                              TABLE 3-3
            SUMMARY OF TECHNICAL AIR MONITORING OBJECTIVES
  Superfund Activity
   Technical A1r Monitoring Objective
RI/FS-Screening APA
Provide preliminary insight about the
existence of air emissions and their
characteristics (magnitude of air
concentrations, constituents Involved and
their distribution) by performing onsite
measurements
Provide preliminary air quality baseline
(onsite and perimeter)
Provide preliminary information for onsite
exposure (workers), perimeter and offsite
exposure (population and the environment)
under existing conditions
Provide air quality data in support of the
design of a good air monitoring program
under the RI/FS step, Including components
of the Health and Safety Plan.
RI/FS-Refined APA
Provide detailed insight about the
existence of air emissions and their
characteristics (magnitude of emissions,
constituents involved and their
distribution) by performing onsite
measurements
Provide onsite air quality data during the
field investigations in support of the Work
Plan, Field Sampling and Analyses Plan and
Health and Safety Plan to protect the field
team
Provide sufficient database for performing
a detailed risk assessment of the public
and the environment based on onsite,
perimeter, and offsite air quality data
under the baseline conditions (no-action
alternative)
Provide sufficient database for performing
the evaluation of remedial alternatives
Provide ground truth to dispersion modeling
calculations.
Remedial Design (field
demonstration)
Provide onsite air quality data during the
implementation of field pilot studies in
support of the Health and Safety Plan for
this step to protect onsite workers
Provide perimeter air quality data for
preliminary assessment of the effects of
the remedial action evaluated.
                                 3-19

-------
                        TABLE 3-3  (Continued)

            SUMMARY OF TECHNICAL AIR MONITORING OBJECTIVES
  Superfund Activity
   Technical A1r Monitoring Objective
Remedial Action
Provide work area air quality data for
routine and nonroutlne air releases to
protect workers and to provide a guidance
for anticipated air concentration at site
perimeter and offslte
Provide work area air quality data in
support of an emergency response air
dispersion model and APA emergency field
guide (see Appendix C)
Provide perimeter and offslte air quality
data to protect public health and the
environment under routine and nonroutlne
air releases
Provide perimeter and offslte air quality
data in support of an emergency response
air dispersion model
Provide work area, perimeter, and offsite
air quality data in support of protective
actions during the remedial action
activities.
Operation and
Maintenance
Provide a long-term air quality database at
the site perimeter and offslte as a part of
assessing the effectiveness of the remedial
action Implemented
Provide a long-term air quality database at
the site perimeter and offslte to
demonstrate the protection of public health
and the environment.
                                 3-20

-------
               Duration of the monitoring program

               Time to obtain results

               Technical expertise of field personnel

               Ability to accomplish the air monitoring program objectives
               by obtaining good quality data with modest uncertainties

     Source-specific APA recommendations have  been presented in Volume I,
as  referenced  1n  Figure  3-3.    These  recommendations  are  based  on  a
standard sequence of APAs, as illustrated  in Figure  3-4.  The APA strategy
presented in Figure 3-4 is based on the premise that  Initially a screening
APA should  be conducted.   The  need  for a refined  APA 1s then determined
based on evaluating screening results, considering the potential to exceed
health  criteria  (as   indicated  by  the  Hazard   Index)  and  monitoring
inaccuracies (as indicated by the Uncertainty Factor).

     The  Hazard  Index  (HI)   for  systemic   toxicants  1s   determined as
follows:
                                                                     (3-D
                 AL1
where
   E1 «  exposure level of the 1th toxicant
   A11   »  maximum acceptable level for the 1th toxicant
   n  -  total number of toxicants
                                   3-21

-------
                        CONDUCT
                       SCREENING
                            APA
      EVALUATE
    HAZARD INDEX
  AND MONITORING
UNCERTAINTY FACTORS
   (•oo Rguro 3-6)
                                                CONSIDER
                                              MONITORING
                                               DETECTION
                                                  LIMITS
                                                INPUT TO
                                              •PA Ml
                         CONDUCT
                          REFINED
                             APA
                          EVALUATE
                     HAZARD INDEX AND
                         MONITORING)
                    UNCERTAINTY FACTORS
Fl«ur» 3-4.   3*l«e«len of
                                               Air Menlter1n0.
                        3-22

-------
The HI for carcinogens (hlc) 1s similar:
                                                                     (3-2)
where
     Ej   =    exposure level  of the jth carcinogen
     DRj  =    dose at a set level  of risk for the jth carcinogen
     m    »    total number of carcinogens

     If any  calculated HI exceeds  unity (I.e.,  1),  then health criteria
may  be  exceeded.    However,  1t  1s  also  necessary   to  consider  the
uncertainty of modeling results.   Because of these uncertainties, the air
concentrations and  associated  HI values could represent  underestimates or
overestimates of  the true  HI  value.   Therefore, as  Indicated  1n Figure
3-5, it 1s  necessary to compare HI and  Uncertainty  Factor (UF)  values to
determine the  adequacy of APA  results  to provide exposure  Input data to
characterize  the  potential  health  Impact  of  Superfund  air  emission
sources.

     Based  on  Figure  3-5,   it  may  be  appropriate  to  conduct refined
monitoring  as  a follow-up  to  screening monitoring  1f  Information 1s not
sufficient  to  definitively  characterize  the   results.    Consider  the
following example:

     •    HI   -    2    based  on  screening  monitoring results  (i.e.,
                         measurements Indicate  that  health  criteria will
                         be exceeded by a factor of 2)

     •    UF   =    ±5   for screening  monitoring results considering the
                         uncertainty  of  the  monitoring/analytical method
                         (I.e.,  monitoring  results   may  overestimate  or
                         underestimate  air  concentrations  by   up   to   a
                         factor of 5)
                                    3-23

-------
               AIR  PATHWAY ANALYSES
                MODELING/MONITORING
                        RESULTS
                           1
                       COMPUTE
                     HAZARD  INOBX
                          (HI)
                             MI1
                  UNOBMTAINTV FAOTOM*
                          
   HI >  UF
 UP  > HI > 1/UP
 HI  <  1/UF
 Information  !•
 Sufficient To
 Choroetefize
  ROlO«OO> A«
   Slonlfleant
  Information !•
  Not  Sufflolont
  To Definitively
   Choraotorlzo
      >  Roloaao
 Inffermatlen !•
 Suffloi«nt To
  (*•!•••• As
  Inslonlfleant
                           T
   INPUT TO
EPA RBMBOIALX
   REMOVAL
   DECISION
    MAKING
    ADDITIONAL
  AIM PATHWAY
ANALYSES SHOULD
  BE CONSIOBREO
   INPUT TO
EPA REMEDIAL/
   REMOVAL
   DECISION
    MAKING
                                       APA
                      3-Z4

-------
     For this case,  the HI  value can be characterized as follows:

          UF > HI  >  1/UF                                             (3-3)

          which 1s equivalent to:

          5.0 > 2.0  > 0.2                                            (3-4)

     Therefore,  for  this   example,  based  on  the  evaluation  criteria
presented  1n  Figure  3-5,   1t   1s  warranted  to consider  the  conduct of
refined air monitoring to confirm screening results.

     Sophistication  level recommendations presented 1n Table 3-1 should be
evaluated  based  on  site-specific  factors.     For  example,   Input  data
collected  during  Step  1  may   Include  previous  air  monitoring results.
Therefore, these  data  may  provide  sufficient  Information  to preclude the
need for  screening  monitoring,  although  refined monitoring may still be
warranted.   Again the  strategy Illustrated  1n  Figure 3-4  and the HI/UF
evaluation criteria presented  in  Figure  3-5 should be used for  monitoring
sophistication level selection.

     The  air  monitoring  objectives  for  specific  Superfund   activities
(e.g., RI/FS,  remedial  action)  are also  Important Input for the selection
of monitoring  sophistication levels.  These  activity-specific  objectives
are summarized 1n Table 3-3.   Input  from  the  RPM/EPM  should be  obtained to
confirm site-specific air monitoring objectives and to ensure that  the air
monitoring level selected 1s consistent with these objectives.

     The  availability   of   appropriate   monitoring  methods   1s   another
significant  factor  for  monitoring  sophistication  level   decision-making.
Certain  constituents,  polychlorlnated blphenyls  (PCBs) for  example,  are
not conducive  to  screening  monitoring.   A further discussion of available
monitoring methods 1s presented 1n Section 3.4.
                                   3-25

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3.3.2     Definition of Monitoring Sophistication Levels

     Alternative  monitoring  sophistication   levels  for  Superfund  APA
applications can be classified as follows:

     •    Screening level

               Screening techniques
               Refined screening  techniques

     •    Refined level

               Refined techniques

     Screening  air monitoring techniques are  generally  associated with
relatively high detection levels  (I.e.,  1n the  range of parts per million
for gaseous contaminants  and  milligrams per  cubic  meter for participates
commensurate with  Industrial  hygiene  measurements)  and frequently provide
near-real-time results 1n the field.   Quite  often,  these detection  levels
exceed health  criteria and ARARs.    Screening  techniques  are  also quite
limited  regarding  the  number   of constituents  that  can  be  evaluated
concurrently.   Therefore, screening techniques  are  most effective for air
monitoring near  the  source  to confirm the presence  of an air release and
to provide input  information  to  support the  development of specifications
for a more refined monitoring  program.

     Candidate  screening air monitoring techniques   are  summarized  in
Table 3-4.  The screening techniques for gaseous constituents presented in
Table 3-4  Include  total  hydrocarbon  (THC)   analyzers,  colorlmetrlc  gas
detection tubes,  electrochemical  alarm cells,  and  screening  portable gas
chromatograph  (GC)  analyzers.   Screening  portable  GC  analyzers have been
developed to  provide  only  gross information on  the  concentration  of an
Individual air toxic constituent  calculated as  an equivalent  to a selected
single chemical  constituent (methane,  for example).   Screening techniques
                                   3-26

-------
                                                TABLE 3-4
                       AN OVERVIEW OF SCREENING AIR MONITORING/SAMPLING TECHNIQUES
Program
Sophistication
Level

Screening
Screening
Screening
Screening

Screening
Screening

Refined screening
Refined screening
Category of
Monitoring/Sampling
Method
Gas Phase:
• Total hydrocarbon
(THC) Analyzers
• Colorimetric gas
detection tubes and
monitors
• Electrochemical
alarm cells
• Screening portable
GC analyzer
Participate Phase:
• Portable pumps with
filters
• Portable pumps with
filters and special
plugs
Gas Phase:
• Portable field GC
analyzers with
constant-
temperature oven
• Field GC laboratory
Detection
Limit

• ppm
• ppm
• ppm
• PPb

• mg/m3
• mg/m3

• PPb
• PPb
Compounds Detected

• Most organics but
not by chemical
species
• Various organics
and inorganics for
a specific chemical
species
• Various organics
for a specific
chemical species
• Species expressed
as equivalent to a
selected single
species

• Most Inorganic
compounds
• Semi volatile
chemical species

• Limited list of
organic compounds
by chemical species
• Limited list of
organic compounds
by chemical species
Monitoring/
Sampling Mode

• Realtime-
continuous
• Historical-
integrated
• Realtime-
continuous
• Realtime -
continuous

• Historical-
integrated
• Historical-
integrated

• Realtime-
continuous
• Historical-
integrated
Typical
Uncertainty
Factors

±1.5 to
±3.0
±1.5 to
±3.0
±1.5 to
±3.0
±1.5 to
±3.0

±1.5 to
±2.0
±1.5 to
±2.0

±1.3 to
±1.5
±1.3 to
±1.5
a    An Uncertainty Factor of ±1.0 indicates a perfect method (i.e., zero uncertainty)

-------
applicable to participates include portable  pumps  with special filters or
plugs.

     Table 3-4 Includes uncertainty values that typify the deviation from
the UF yielded by  a perfect method where a perfect  method  will  yield an
uncertainty factor of ± 1.0.  Uncertainty of ± 3.0 means a deviation of ±
200 percent from  the perfect  method or value.

     The typical  uncertainty values are  based  on a qualitative assessment
of the various screening methods, experience, and field applications.  The
uncertainty  values  depend  on  the  number  of  the  air   toxic  compounds
involved,  the   concentration   of  the   individual   compounds,   and  the
interferences introduced.

     Refined screening  air monitoring  techniques  can  provide reasonably
accurate  information  on ambient  air  quality of organic  compounds 1n the
gas phase at the ppb  level.   These refined screening techniques utilize a
combination  of   air  sampling  and  a  near-real-time  analytical   analysis
without the  use  of offsite laboratory facilities.   Refined screening air
monitoring  techniques  listed   in Table  3-4  Include  field  portable  GC
systems.

     Although similar to refined methods, refined  screening  air monitoring
techniques have the following limitations:

          The 11st of chemical species that can  be accommodated  1s shorter
          than the one handled by a fully equipped offsite laboratory.

          Only   an   uncomplicated  matrix  of  chemical   species   can  be
          analyzed.

          As  field  techniques,  these  techniques  lack  the  ability  to
          implement the comprehensive QA/QC  procedures  used  by a  certified
          offsite laboratory.
                                    3-28

-------
     Refined air monitoring is applicable  to situations when high-quality
data are required and the response  time  for obtaining air quality results
is not near real time.  It also is applicable as a supplement to the near-
real-time  air  monitoring  data  obtained  through  the  use  of  a  refined
screening  technique  during  the  implementation of  remedial  actions.    In
such a  case,  the refined air monitoring  technique  provides high-quality
results  to  supplement  and  verify  results  of  the  refined  screening
monitoring.   Of  course,  the comparison   between  the  two  is based   on
historical  data.

     A  listing  of typical  refined air monitoring  techniques is presented
in Table 3-5.   Although a myriad of refined air  monitoring techniques  is
available,  the  process  of selecting the most suitable  one  1s difficult.
This  is because  of  the technical  limitations  of  available monitoring
methods  and  the large  number of target compounds  that  may be Involved.
Furthermore, the  field  of  air  toxics  monitoring  for  protecting public
health  and the  environment  is 1n the  developing  stages compared with the
field  of  air  monitoring for criteria  pollutants,  which  is considered
mature.

     In  spite of the high quality of  the  chemical  analysis involved with
refined  air monitoring  techniques,  it  1s  possible  that the data  obtained
will be  useful  only  1n  a qualitative rather than  a quantitative way.  The
reasons  for  this  could  be  many.    Several  factors that  could affect the
quality of the data Include  the following:

     •    Large number of compounds Involved

     •    Variability  1n the concentrations of  Individual  compounds and
          the need for low detection limits

          Potential  for the formation of artifacts during sampling

     •     Interference between compounds during analysis
                                   3-29

-------
                                                      TABLE  3-5


                              AN OVERVIEW OF REFINED AIR MONITORING/SAMPLING TECHNIQUES
Program
Sophistication
Level
Refined



Refined


Category of
Mon 1 tor i ng /Samp 1 1 ng
Method
Gas Phase:
• Traps (sorbents and
cryogenics) and
laboratory analysis
• Whole air samplers
(bags and
canisters) and
laboratory analysis
• Liquid impingers
Part icu late Phase:
• High-volume
samplers with glass
fiber filter.
membrane filter or
teflon filter
• High-volume
samplers with a
glass fiber filter
and polyurethane
foam*
Detection
Limit

• Fraction
of a ppb
to ppb
• Fraction
of a ppb
to ppb
• Fraction
of a ppb
to ppb

• pg/m3
• ug/m3
Compounds Detected

• Many organic
compounds by
chemical species
• Many organic
compounds by
chemical species
• Aldehydes, ketones,
phosgene,
cresol/phenols

• Inorganics
• PCBs and other
semi volatile
organic species
Monitoring/
Sampling Mode

• Historical-
integrated
• Historical-
integrated
• Historical-
integrated

• Historical-
integrated
• Historical-
integrated
Typical
Uncertainty
Factors

±2.0
±1.1
±1.2

±1.3
±2.0
I
u*
O
     *Polyurethane foam  (PUF)  plug  is  designed  to  collect  semivolatile  organic  gases.

-------
          Variable response of the analytical  system as a function of the
          specific compound

     This  Implies  that a  cost-benefit  assessment  may  be useful.   This
assessment  may,   based  on  the  factors  involved,   show  that  a  refined
screening  methodology  utilizing  a  portable  field  GC  analyzer  is  more
beneficial  for  the application  involved than  is a  refined  methodology.
Therefore,  the   UFs   for   candidate  monitoring   approaches  should  be
considered as discussed in Section 3.3.1.   This approach 1s also  included
in the discussion on the application of monitoring sophistication levels.

     An  expanded  discussion  of  alternative  screening  and  refined  air
monitoring methods/equipment 1s presented in Section 3.4.

3.4       STEP 3 - DEVELOP  MONITORING PLAN

3.4.1     Overview

     An  air monitoring plan  should  be  developed for  each  Superfund APA
application.   The  objective  of  the  plan  is  to document  the Technical
Specifications for a site/source-specific  monitoring program.   The plan
also provides an opportunity  for peer review  and RPM/EPM approval of the
monitoring  program.    Developing  a  site/source-specific  monitoring plan
involves the following major elements, as illustrated 1n Figure  3-6:

     •    Select monitoring constituents
          Specify meteorological monitoring program
     •    Design air monitoring network
     •    Document air monitoring plan

     Major  Input  to  the  development  of  an  air monitoring  plan  should
include  the Information collected during Step 1 (e.g.,  identification of
previous  APAs,  ARARs), the  monitoring  constituent  target 11st developed
during Step 2, and available EPA technical guidance.
                                    3-31

-------
INPUT DATA
  (STEP  1)
     EPA
 GUIDANCE
 MONITORING
CONSTITUENT
 TARGET  LIST
   (STEP  2)
    OTHER
 TECHNICAL
  GUIDANCE
              SELECT  MONITORING
                 CONSTITUENTS
                  (Flgur*  3-7)
                     SPECIFY
                 MBTBOROLOOICAL
              MONITORING PROGRAM
                  (Figure 3-8)
                   DESIGN AIR
              MONITORING NETWORK
                   (Flgur*  3-9)
                DOCUMENT  AIR
              MONITORING  PLAN
                 (Figure 3-1O)
                    INPUT TO
               STEP 4 - CONDUCT
                   MONITORINQ
   »-•.  9t*p a - O*v*lop Menlterlna Plan.
                   3-32

-------
     Procedures for the development of an air monitoring plan are provided
in the subsections that follow.

3.4.2     Select Monitoring Constituents

     The  selection  of  air  monitoring   constituents  is  frequently  a
challenging  task  for  Superfund  applications  because  of  the  extensive
number of  potential  release constituents.   Sampling/analytical  technical
factors and project budget limitations generally necessitate the selection
of a limited subset of target constituents.

     The  selection of  target  air monitoring  constituents  involves the
following key factors:

          Physical and chemical  properties of the constituents

               Physical phase (gas, particulate)
               Volatility
               Thermal  stability
               Polarity
               Ion character

          Toxlcity and  health  effects  (risk  assessment)  of the chemicals
          involved

          Estimated  concentration  of  a  constituent  relative   to  other
          constituents and potential interference

          Availability of  standard sampling and  analysis methods  and their
          performance

          Overall  and technical project objectives

      •    Data quality objectives and resource constraints
                                    3-33

-------
     A  summary  of  the recommended  procedure  for  the  selection  of  air
monitoring constituents is presented in Figure 3-7.

     A  list  of  the  compounds  included  in  the  Hazardous  Substances List
(HSL) developed  by EPA for  the Superfund  program  is  presented  in Table
3-6.   This  list  is a  composite of  the Target  Compound  List  (TCL)  for
organics and the Target Analyte List (TAL) for  inorganics.  Table 3-6 also
includes  examples   for  additional  potential   Superfund  air  emission
constituents  (e.g.,  HCN,  H2$,  HC1).    Therefore,  Table  3-6 represents  a
comprehensive list  of  compounds from  which  a  list of  target  air  toxics
compounds can be selected.

     Emission rate APA results  should  be obtained prior to the conduct of
air monitoring  studies  based on Volume  I  recommendations.  These  results
as well  as  air  monitoring data (as available)  should be used to identify
appropriate  site-  and  source-specific  monitoring  constituents  from Table
3-6.  Constituents  included  in  ARARs  Identified during Step 1 should also
be used to identify candidate monitoring constituents.

     The  limited  set  of  candidate   monitoring   constituents  based  on
previous  APAs   and  ARAR  considerations   should  be  used  to   compute
constituent-specific HI values, as previously discussed.

     The HI  values  computed  should then  be  ranked from highest to lowest
1n order to  develop a  priority list of candidate  monitoring constituents.
The final constituents selected for air monitoring should  be a function of
the APA sophistication level (as indicated in Figure 3-7).

     Monitoring  Indicators  for screening  applications should be selected
for  one  to  five  constituents with   the  highest  HI  values  for which
appropriate  monitoring methods  are  available.   Monitoring  Indicators could
include  total  hydrocarbons  for  organics  and   compound  class  Indicators
(e.g.,   ethers,   aromatics)   for   organics   and  inorganics.    Specific
constituents could  also be selected as  monitoring  targets  for organics and
inorganics.
                                    3-34

-------
    AIR CONCENTRATION
               BASED ON
                DATA •
       3TEP 1 INPUT
         (T«b« 3-2)
      PREVIOUS AIR
   MONITORING DATA -
      STEP 1 INPUT
        
 POM t-» CON»TmjBMT«
WITH MIOMaVr M VALUM
POM WMMM APPttOPRIATI
 MONfTOMMa MKTMOO*
                          REPINED I3CREENINO
siuer s-ie MONITOBINO
  coMarrruiNTa WITH
 HIOMK9T  Ml VALUB8 PON
  WMION APPMOPMATE
  MONITOMIMO METMOOa
     AM AVAItABLl
                                                  9BLBOT
  FV.I ^^p^vvwv • • • ^^mm^m • w ^
   O.1 Ml (TOTA*. MIXT
POM WMIOM APPMOPMIATV
 MOMITOMIMO MCTHOOa
    ARE AVAIiAMJB
                              INPUT TO
                          AIR  MONITORING
                                PLAN
                          RBBVALUATB TARGET
                            UST BA3ED ON
                          CURRENT MONITOR-
                              INO RESULTS
     Flgur* 3-7.
                                Cen«tHumit«.
                               3-35

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             TABLE 3-6 (PAGE 1 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
       FOR AMBIENT AIR MONITORING  STUDIES
Broad Band
Volatile Organics




































Compound Class
Aliphatics
aromatlcs





Halogenated Species





















Oxygenated Species



Sulfur-Containing
Species
N1 trogen-Contai ni ng
Species
Representative Compounds
vinyl acetate
benzene
toluene
ethylbenzene
total xylenes
styrene
chlorobenzene
carbon tetrachloride
chloroform
methylene chloride
chlorome thane
1 , 2-d i ch 1 oropropane
trans-l,3-dichloropropene
cis-l,3-dichloropropene
bromoform
bromomethane
bromod i ch 1 oromethane
di bromoch 1 oromethane
1 , 1 ,2, 2-tetrachloroethane
1 , 1, 1-trichloroethane
1,1,2-trlchloroethane
1,1-dichloroethane
1 , 2-d i ch 1 oroethane
chloroethane
tetrachloroethene
trichloroethene
1,2-dichloroethene
1,1-dichloroethene
vinyl chloride
acetone
2-butanone
2-hexanone
4-methyl -2-pentanone
carbon disulfide

benzonitrlle*

                        3-36

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             TABLE 3-6 (PAGE 2 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
       FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Volatile Inorganics

Semi-Volatile
Organics



Compound Class
Acid Gases
Sulfur Containing
Species
Phenols
Esters
Chlorinated Benzenes
Amines
Representative Compounds
cyanide*
hydrochloric acid*
hydrogen sulfide*
phenol
2-methyl phenol
4-methyl phenol
2,4-d1methylphenol
2-chlorophenol
2,4-dichlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
pentach 1 oropheno 1
4-chloro-3-methy 1 phenol
2-nitrophenol
4-nitrophenol
2f4-d1nitrophenol
4, 6-d1n1tro-2-methyl phenol
bis(2-ethylhexyl)phthalate
di-n-octyl phthalate
d1-n-butyl phthalate
diethyl phthalate
butylbenzyl phthalate
dimethyl phthalate
1,2-dichlorobenzene
1,3-dichlorobenzene
l,4-d1chlorobenzene
1,2,4-trichlorobenzene
hexachlorobenzene
nitrobenzene
2,6-d1nitrotoluene
2,4-d1n1trotoluene
3,3'-d1ch1orobenz1d1ne
n-ni trosodimethy 1 ami ne
n-n1 trosodi -n-propy 1 ami ne
n-nitrosod1phenylamine
aniline
2-n1troan1l1ne
3-n1troaniline
4-nitroan1l1ne
4-chloroanil1ne
                        3-37

-------
                    TABLE 3-6  (PAGE 3 OF 4}
        CLASSIFICATION OF ORGANIC AND  INORGANIC  COMPOUNDS
               FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Compound Class
Representative Compounds
                 Ethers
                   jis(2-chloroethy1)ether
                   3is(2-chloroisopropyl)ether
                   bromophenyl-phenylether
                   4-chlorophenyl-phenylether
                 Alkadienes
                   hexachlorobutadlene
                   hexach1orocyc1opentad iene
                 Miscellaneous
                 Aliphatics and
                 Aromatics
                   ienzoic acid
                   aenzyl alcohol
                   bis(2-chloroethoxy)methane
                   dibenzofuran
                   hexachloroethane
                   isophorone
                 Polynuclear Aromatic
                 Hydrocarbons (PAHs)
                   acenaphthene
                   acenaphthylene
                   anthracene
                   benzo(a)anthracene
                   benzo(b)fluoranthene
                   benzo(k)fluoranthene
                   benzo(g,h,1)perylene
                   benzo(a)pyrene
                   chrysene
                   d1benz(a,h)anthracene
                   fluoranthene
                   fluorene
                   1ndeno(l,2,3-cd)pyrene
                   naphthalene
                   2-methylnaphthalene
                   2-ch1oronaphthalene
                   phenanthrene
                   pyrene
                 Pesticides
                   alpha-BHC
                   beta-BHC
                   delta-BHC
                   gamma-BHC
                   heptachlor
                   heptachlor  epoxide
                   4,4'-DDT
                   4,4'-DDD
                   4(4'-ODE
                   endrin
                   endrin ketone
                   endrin aldehyde
                                3-38

-------
                          TABLE 3-6 (PAGE 4 OF 4)

             CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
                     FOR  AMBIENT AIR MONITORING  STUDIES
      Broad Band
   Compound Class
   Representative Compounds
                      Pesticides
                      endosulfan  I
                      endosulfan  II
                      endosulfan  sulfate
                      aldrin
                      dleldrin
                      chlordane
                      methoxychior
                      toxaphene
                       Polychlorinated
                       Biphenyls  (PCBs)
                       Arochlor
                       Arochlor
                       Arochlor
                       Arochlor
                       Arochlor
                       Arochlor
                       Arochlor
         1016
         1221
         1232
         1242
         1248
         1254
         1260
Non-Volatiles
Inorganic Metals and
Non-Metals
aluminum
antimony
arsenic
barium
beryllium
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
mercury
nickel
potassium
selenium
silver
sodium
thallium
tin
vanadium
zinc
Note:  Compounds  identified  by an asterisk  (*) are not contained on the USEPA
Hazardous Substance  List  (HSL).
                                      3-39

-------
     Refined  screening   monitoring  applications   should   Include  the
selection of 5 to  10  monitoring constituents with  the highest HI values.
This approach  should  facilitate  the  preliminary characterization  of air
releases at Superfund  sites.  Again, the monitoring list selection process
should  consider  the  availability   of   appropriate  monitoring  methods
commensurate with health  and safety criteria.

     Target monitoring constituents for  refined  APAs  should  include all
constituents with an  HI  value  greater than or equal  to 10 percent of the
composite HI value for the  total  mix.   These constituents are expected to
represent the greatest contributors to potential  health impacts.

     The target  monitoring  list  should  be  periodically  reevaluated, and
revised  if  warranted, as monitoring  results  become  available.   This is
particularly useful for  refined monitoring studies that  are long term in
nature  (e.g.,  during  remedial  actions).    For these  applications  it may
also be effective to periodically  (e.g., monthly) sample and analyze  for  a
more comprehensive 11st  of  compounds  to confirm the representativeness of
the routine-monitoring target 11st.

3.4.3     Specify Meteorological Program

     A  meteorological  monitoring  program should be  an  integral  part of
Superfund air monitoring activities.   A meteorological survey can be used
to  design  the  air   monitoring  network  based  on  local   wind  patterns.
Meteorological  and  air  quality  data  collected  can  be  used  for  the
interpretation  of  air   concentration  data   considering   upwind/downwind
exposure conditions.   A recommended procedure  for the  development  of  a
site-specific meteorological program design  1s presented in  Figure 3-8.

     The number and location of meteorological stations needed for  a site-
specific   application   depend   on   local   terrain    conditions.      One
meteorological  station  1s  generally  sufficient for   flat-terrain  sites.
However, for complex-terrain  sites  it  may  be  necessary  to have  multiple
                                    3-40

-------

DETERMINE NUMBER
AND LOCATION OF
METEOROLOGICAL
STATIONS

FLAT TERRAIN
1 STATION


t
COMPLEX TERRAIN
1-3 STATIONS
                    _L
               DETERMINE
               EXPOSURE
                 HEIGHT
    SCREENINGS'
REPINED SCREENING
       2-3  m
REFINED
               DETERMINE
              MONITORING
              PARAMETERS
    SCREENING/
REPINED SCREBNINO
 e Wtnd Dlraatton
 e Wind Spaad
 e Sigma  Thata
 REFINED
                        a Primary
Sigma Thata
T«mparatura
Praelpitatten
Humidity
Praaaur*
             DETERMINE DATA
               • RECORDING
                APPROACH
             CONDUCT M«TBO«O-
             LOQICAk 9UMVKV TO
            SUPPORT AIR MONITOR*
            I NO NBTWORK OBSIttN
                (A* N*o«««aryl	
     SCREENINax
 REPINED SCREENING
 REFINED
                  INPUT TO
               AIR  MONITORING
                    PLAN
                 3-41

-------
stations to represent major onsite/local air flow paths.  Generally one to
three  stations  will  be  sufficient  for  these  sites.    To  ensure  a
representative  exposure,  it   is   recommended  that  the  meteorological
stations be located  at a  distance  of at least  10  times  the height of any
nearby obstruction.

     Meteorological  sensor exposure  height  should  be 2-3 meters above the
ground  surface  for   screening  and  refined  screening  applications.   This
approach facilitates  the  use of portable  stations, which  can be rapidly
deployed.  For  refined  analyses the primary exposure  height  should be 10
meters  (for wind  and stability data) and 2 meters  for parameters that do
not directly affect  atmospheric dispersion.  For elevated releases such as
those from incinerators,  primary meteorological parameters  should also be
measured at stack height to the extent practicable.

     Meteorological   monitoring  parameters  for  Superfund applications can
be classified as follows:

     •    Primary parameters

               Wind  direction

               Wind  speed

               Sigma  theta  (I.e.,  the  horizontal  wind direction  standard
               deviation, which is  an indicator of atmospheric stability)

     •    Secondary parameters

               Temperature

               Precipitation
                                    3-42

-------
               Humidity

               Atmospheric  pressure

     Primary parameters are  representative of  site  dispersion conditions
and  should  be   included  1n   all  meteorological  monitoring  programs.
Secondary  parameters  are  representative  of  emission conditions  and are
generally only recommended  for refined air monitoring activities.

     Recommended  meteorological  monitoring  system  accuracies/resolutions
and sensor response characteristics  are  summarized in Tables 3-7 and  3-8,
respectively.   Field equipment  used to  collect  meteorological  data can
range  1n  complexity  from  very  simple analog or  mechanical pulse  counter
systems   to   microprocessor-based   systems.     A  combination  of   these
approaches  is  recommended  for  Superfund  applications.   This approach  is
generally  not  expensive but  it facilitates  the  convenient collection  of
meteorological data that can be processed  onslte at a field office  using
personal  computers  (PCs).   The chart recorders provide a  low-cost  backup
system  if  the digital data are not available.

     A  meteorological   survey   should  also  be  conducted   to  support  air
monitoring network  design.    Exceptions  would  include sites  that  have
historical onsite meteorological data that  are  consistent with  the  DQOs  or
flat-terrain  sites for which  representative offsite  data  are  available.
The  duration of  the  meteorological  survey should  range from  1 week for
screening/refined  screening  applications  to  4  or more   weeks  for  the
conduct  of  a  refined  air  monitoring  program.    The  survey  should  be
conducted during a period (season and  time of day)  representative of the
planned  air  monitoring   program  and   air  emission  source  operational
schedules.  However,  it may  be  necessary to use historical  offslte data to
estimate  seasonal  effects  for  planning  purposes  if  the   air  monitoring
program 1s scheduled to last for more than a few months.

      Additional   recommendations   on meteorological  measurements  can  be
 obtained from the following  sources:
                                    3-43

-------
                                TABLE 3-7
              RECOMMENDED SYSTEM ACCURACIES AND RESOLUTIONS
 Meteorological Variable
 System Accuracy
Measurement Resolution
Wind Speed

Wind Direction
Ambient Temperature
Oew Point Temperature
Precipitation
Pressure
Time
±(0.2 m/s + 556 of
    observed)
    ±5 degrees
     ±0.50C
     ±1.50C
 ±10% of  observed
 ±3 mb (0.3 kPa)
    ±5 minutes
        0.1  m/s
       1 degree
         O.loc
        0.3 mm
        0.5 mb
                                   3-44

-------
                                TABLE 3-8

     RECOMMENDED RESPONSE CHARACTERISTICS FOR METEOROLOGICAL SENSORS
  Meteorological Variable
           Sensor Specif1cat1on(s)*
Wind Speed

Wind Direction


Temperature

Dew Point Temperature
Starting Speed <0.5 m/s; Distance Constant <5m

Starting Speed <0.5 m/s 9 10o Deflection;
Damping Ratio 0.4 to 0.7; Delay Distance <5m

Time Constant <1 minute

Time Constant <30 minutes; Operating
Temperature Range -30QC to +30°C
*From Table  5-2.   On-Site  Meterological  Program Guidance  for Regulatory
Modeling  Applications,  U.S.  EPA,  Office  of  Air   Quality  Planning  and
Standards, Research Triangle Park,  N.C.,  27711.   June 1987.
                                    3-45

-------
    U.S.  EPA.   June  1987.   On-Site  Meteorological Program  Guidance for
    Regulatory Modeling  Applications.   EPA-450/4-87-013.   Office  of Air
    Quality Planning and Standards.   Research Triangle  Park,  NC  27711.

    U.S.  EPA.    February  1983.    Quality  Assurance  Handbook  for  Air
    Pollution   Measurements   Systems:	Volume   IV.   Meteorological
    Measurements.   EPA-600/4-82-060.   Office  of Research and Development.
    Research Triangle Park, NC  27711.

    U.S.  EPA.   July  1986.   Guidelines  on Air Quality  Models (Revised).
    EPA-405/2-78-027R.    NTIS  PB  86-245248.    Office  of  Air  Quality
    Planning and  Standards.  Research Triangle  Park, NC  27711.

    U.S.  EPA.  May 1987.   Ambient Monitoring  Guidelines for Prevention of
    Sionifleant  Deterioration fPSDU    EPA-450/4-87/007.   Office  of Air
    Quality Planning and  Standards.   Research Triangle  Park,  NC  27711.

3.4.4      Design Monitoring Network

    The air monitoring  network design will be affected by factors such as
site-specific  source,  receptor,   and   environmental characteristics   (see
Table  3-9).   Therefore,  the  design  of  an air  monitoring network  for  a
Superfund APA must be  decided  on  a  case-by-case  basis.    A  recommended
procedure  for  designing  an  air  monitoring  network  is  presented  in
Figure 3-9.   Key  components of  the monitoring  network design include:

          Number  of locations  of monitoring stations
          Probe  siting  criteria
          Program duration and  frequency of monitoring
          Sampling and  analysis methods
          Air monitoring equipment

     The following is a discussion of  each of  these components.
                                   3-46

-------
                              TABLE 3-9
     FACTORS AND ASSOCIATED ELEMENTS THAT AFFECT THE DESIGN OF AIR
                MONITORING PROGRAMS FOR SUPERFUND APAs
        Factor
                   Elements
Technical air
monitoring objectives

Source Characteristics
Receptor data
Environmental
characteristics
Data Quality
Objectives
see Table 3-2


•  Nature and extent of site sources (lagoon,
   landfarm, land disposal, processing
   facility, tank farm, etc) and their size
•  Constituents involved and their physical
   state (gas, particle, total)
•  Estimated emission rates (measured or
   calculated)
•  Site source grouping

•  Historical air quality data for the site
   area representing onsite, perimeter, and
   offsite measurements and the quality of the
   data
•  Results of air dispersion modeling and
   locations of high calculated air toxics
   concentrations
•  Number and locations of sensitive receptors
   (population; sensitive population
   locations-schools, hospitals, etc;
   sensitive environmental species and
   settings such as flora and fauna, state
   parks and monuments, national parks and
   monuments, etc.) and distance to these
   locations

•  Historical records of meteorological data
   representing the site area including
   diffusion climatology and special
   conditions conducive to high concentration
   of airborne contaminants
•  Topography in the site area and its
   potential effect on local dispersion
   conditions, and its proximity to the site.
•  Water bodies in the site area, number, size
   and proximity to the site.

•  Database for worker protection only
•  Database for worker, public and
   environmental protection
                                 3-47

-------
                        TABLE 3-9 (Continued)
    FACTORS AND ASSOCIATED ELEMENTS THAT AFFECT  THE  DESIGN OF AIR
                MONITORING PROGRAMS FOR SUPERFUND APAs
        Factor
                Elements
Data Quality
Objectives
Detection limit for constituents involved
Precision and accuracy of monitoring and
analyses methodologies
Data representativeness
Data completeness
Data comparability
Data use for Superfund APA application
Data Quality
Objectives (continued)
Source Characteristics
Constraints
Receptor Constraints
Environmental
Constraints

Data Quality Objective
Constraints

Resource Constraints
Frequency of monitoring and program
duration (short - few days to weeks;
intermediate - few weeks to few months;
long- a year or more)
Monitoring mode (real time - instantaneous,
continuous historical - integrated)
QA/QC requirements (data validation.
equipment calibration, equipment and
documentation, data handling, chain of
custody, audits)

Large number of air toxics compounds with
high level of air emissions (volatile;
semi-volatile, base/neutral, pesticides,
PCBs, inorganic)
Mixed physical state (gas, particulates)
non homogeneous source
Incomplete source characterization and data
gaps

Large number of receptors are Identified
for the specific application
Large number of obstructions close to the
receptors identified (trees, bushes,
structures, etc.)
Accessibility to receptors
Availability of utilities
Security

complex topography
large water body(ies)

Limited or no applicable monitoring and
analysis methodologies

Limited budget
Limited time
                                 3-48

-------
METEORO-
 LOGICAL
  SURVEY
   DATA
               CONSIDER DESIGN
                    FACTORS
                   (Table  3-9)
DETERMINE NUMBER
AND LOCATIONS OF
  AIR MONITORING
     STATIONS
   (Table 3-10)
DISPERSION
 MODELING
 RESULTS
               DETERMINE PROBE
               EXPOSURE HEIGHT
                  (Table 3-11)
                        JL
               DETERMINE PROGRAM
               DURATION/SAMPLING
                   FREQUENCY
                  (Table 3-12)
    EPA
 GUIDANCE
(Tabl*  3-13)
SELECT  MONITORING
      METHODS
    (Table  3-13)
   OTHER
 TECHNICAL
 GUIDANCE
(Appendix A)
               SELECT  MONITORING
                    EQUIPMENT
               (Table  3-22.  3-23)
                     INPUT TO
                  AIR MONITORING
                       PLAN
           O««l«n Air Monltorln* Network
                    3-49

-------
Determine Number and Locations of Monitoring Stations

     The number and location  of  monitoring  stations for an air monitoring
network depend on the site-specific characteristics listed below.

     •    Results of air  dispersion  modeling for  the  site area utilizing
          an  atmospheric  dispersion model  applicable  to the  source and
          site (see Section 2.0 in this  volume)

     •    Environmental   characteristics  (meteorology,  topography,  soil
          characteristics, etc.)

          Receptor   characteristics    (population   centers,   sensitive
          population and  environmental  locations,  locations of calculated
          high concentrations of  air toxics)

          Source  characteristics    (type   and  extent  of  contamination,
          locations of  hot spots, etc.)

          Siting constraints

          Duration of the monitoring program

     Meteorological variables  affecting monitoring network design  include
wind  direction,  wind  speed, and  atmospheric  stability.  These parameters
can  be used  to define  prevailing wind  patterns  and  characterize  local
dispersion conditions.

     Air monitoring  programs  that  last for  only  2 weeks  or less  (e.g.,
screening APAs)  require  some  judgment  about the  placement of monitoring
stations  and  their numbers.    This is  because  the  use  of historical
meteorological  data would  generally  not  provide  accurate information on
the  meteorological  conditions for the few  days  of sampling  and  analysis.
However, the  results of a meteorological survey onsite  (see  Section 3.4.2)
conducted  just  prior  to  screening  can  help to   identify  expected wind
                                   3-50

-------
patterns and downwind sampling  sectors,  and to characterize temporal wind
direction variability.   Meteorological  forecast information  can  also be
used  to  deploy  screening  air  sampling  equipment.    Therefore,   it  is
recommended that  air screening  samples be  taken with  portable sampling
equipment.

     The following factors should be considered  in selecting locations and
the  number  of monitoring  stations  for  air monitoring  programs  with the
duration of several  weeks to several months:

     •    Predominant wind  directions,  based  on historical  records, for
          the  monitoring period under consideration.  This may involve the
          review of  daily, weekly,  and monthly meteorological  records.

          Time  of  the   year   the   monitoring   program   is  scheduled,  to
          account,  to the extent possible, for seasonal  effects that  could
          cause either  high or  low ambient air  concentrations.   Seasons
          that in general do  not exhibit high-ground-level concentrations
          of  the  constituents  Involved  should  not   be  considered  as
          candidate  periods for air monitoring, to the extent  possible.

     •    Use  of  a  dispersion  model  (screening or  refined)  to calculate
          ground-level  concentrations   in   the  site   vicinity  and  to
          determine   locations  of  maximum  calculated  concentrations for
          short-term  (up  to  24 hours)  averages and  long-term (monthly,
          seasonal,   and  annual)  averages.    Input  into  the dispersion
          model,   including   source    data,    meteorology,   topography,
          population  centers,  sensitive  population,   and  environmental
          setting locations, should be defined for the  time averages  under
          consideration  in  order  to  obtain  model output   showing the
          receptors   of  maximum   impact   on   the   population   and  the
          environment.   For example,  meteorological conditions conducive
          to  high-ground-level  concentrations  of air  toxic   constituents
          such  as  nighttime  drainage  flows   are  quite  important for
          consideration  in  selecting  the   locations  of  air monitoring
                                   3-51

-------
stations  for the  implementation  of  the  remedial  action  step
under the Superfund project.

Source size and configuration.  It is  preferred  to  locate  an air
monitoring  station  downwind from  a  source  so  that  it will  be
exposed to  a  large  fetch of the source  area for a  long period.
considering the frequency  of  occurrence of wind direction.  This
will  ensure that  source emissions  are transported  toward  the
monitoring  station  from  a large portion of  the source area  for
an extended period.   In  this  respect,  the fetch should cover  an
area  that  1s  exposed to  high concentrations  for  an extended
period.

Locations  of  sensitive  receptors  at  the  site  perimeter  and
offslte.   The  locations and  number  of monitoring  stations  at
sensitive    receptors   should    be    evaluated    considering
meteorological   conditions   conducive    to    high-ground-level
concentrations  of  airborne air  toxic  constituents  and   their
frequency  of occurrence.   From  a  practical  viewpoint,  it  is
important to consider the following:

     Locations    of     anticipated     high-ambient-ground-level
     concentrations of air  toxic  constituents and the  frequency
     of  occurrence  of  the meteorological conditions  that  are
     conducive  to these  levels.    Depending  on the  monitoring
     objective, the first priority should  be to  select  locations
     that will most frequently be exposed  to high  concentrations
     of such constituents.

     Population  and  environmentally   sensitive  locations.    In
     evaluating  locations,  it  1s  Important   to  consider  the
     objectives   of  the   monitoring   program:     to  provide
     Information on possible high  impact at  sensitive receptors,
     specifically,  a  high  dose  to  an  Individual  person  or
     species or a high Integrated dose to  the  nearby population.
                          3-52

-------
This  factor will  dictate  the  selection  of  a monitoring
station  representing  small  but  highly  sensitive  or  large
but less sensitive population and environmental species.

Meteorological  conditions

     Wind directions and speeds  and atmospheric  stabilities
     conducive  to  high-ground-level  concentrations  of air
     toxic  constituents  for  both   short-  and   long-term
     averaging  periods.

     Local day/night wind flow and stability conditions for
     the area and monitoring period under consideration.

     Characteristics of  the  regional  flow regime  for the
     area  and  the  monitoring period  under consideration.
     For example,  it may occur  that  the regional  flow for
     this  site  for the  monitoring  period of  Interest  is
     generally   southwesterly,  and  that  the   local   night
     drainage    flow     under    stable    conditions     is
     northeasterly.   Accordingly,  a  monitoring  location
     southwest  of the site would be the  upwind  location for
     the  regional  flow  and  the  downwind  location  for the
     more limiting local  flow.

     Results of previous air quality monitoring  programs  in
     the  vicinity  of  the  site  that  could  be considered
     applicable to the  case in question.

     Results of  previous  air dispersion  calculations for
     similar sources  with  meteorological  data considered
     representative of  the site conditions.

Topographical features  that would  influence  the  advection
and transport of  air toxic constituents.  Examples  Include
                    3-53

-------
               land surface  elevations,  valley channels,  and  the  land-
               water interface.

     A1r  monitoring  station  number  and  location  recommendations   are
summarized  1n  Table  3-10  based  on consideration  of  the  above  factors.
These recommendations address the  identification of air monitoring  target
sectors based on the following analysis for the planned monitoring period:

     •    Historical prevailing  wind direction

     •    Maximum short-term (24-hour)  dispersion modeling predictions

          Maximum  long-term  (monthly,  seasonal, or  annual,  commensurate
          with  the   planned  monitoring  duration)  dispersion   modeling
          predictions

          Sectors associated with sensitive offsite receptors

     •    Most recent 24-hour wind forecast Information

     Portable air monitoring stations are recommended for use at locations
Identified  based  on  the  most  recent  24-hour  wind forecast  information.
This  approach  provides  maximum  flexibility; that 1s, 1t permits variation
of  the sampling network design to  accommodate changes in day-to-day  wind
conditions.  •

     The  air monitoring  siting recommendations presented  1n Table  3-10
Include the  following zones for each of  the APA  sophistication levels:

      •    Source boundary

               Upwind
               Downwind

          Site boundary
                                    3-54

-------
                                                        TABLE 3-10


                             AIR MONITORING STATION  NUMBER  AND  LOCATION RECOMMENDATIONSa.b.c

• Screening APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
• Refined Screening APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
Based on
Historical
Prevailing
Wind
Direction


NA
NA

NA
NA


1- Stationary
1 -Stationary

1- Stationary
1-Stationary
Based on Maximum
Short-Term
Dispersion Modeling
Concentration
Sector


NA
NA

NA
NA


NA


NA

Based on Maximum
Long-Term
Dispersion Modeling
Concentration
Sector


NA
NA

NA
NA


NA


NA

Based on Sectors
Associated with
Sensitive
Offslte
Receptors


NA
NA

NA
NA


NA


NA

Based on
Most Recent
24-hour Wind
Forecast
Sector(s)d


1 Portable
3 Portable

1 Portable
3 Portable


1 Portable
3 Portable

1 Portable
3 Portable
at
ui

-------
                                                        TABLE  3-10

                       AIR MONITORING STATION NUMBER AND LOCATION RECOMMENDATIONS*,b,c (Continued)

• Refined APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
Based on
Historical
Prevailing
Wind
Direction


1-Statlonary
1 -Stationary

1-Stationary
1-Stationary
Based on Maximum
Short-Term
Dispersion Modeling
Concentration
Sector


NA
NA

1-Stationary
1-Stationary
Based on Maximum
Long -Term
Dispersion Modeling
Concentration
Sector


NA
NA

1-Stationary
1-Stationary
Based on Sectors
Associated with
Sensitive
Offslte
Receptors


NA
NA

Ad
Ad
Based on
Most Recent
24-hour Wind
Forecast
Sector(s)d


1 Portable
3 Portable

1 Portable
3 Portable
I
01
0»
    NA = Not applicable

    a  =  Upwind stations based on historical wind data and dispersion modeling results can frequently be
          consolidated to one location
    b  =  Additional monitoring stations may be required for complex-terrain sites
    c  =  Offslte monitoring should be conducted on an ad hoc basis commensurate with site-specific project needs
    d  =  If Invariant wind directions are predicted, one station should be located downwind based on this prediction
          plus one station In each adjoining 22.5-degree sector

-------
               Upwind
               Downwind

     Upwind  stations  will  provide   background   air   concentration  data.
Frequently, upwind stations can be consolidated into one  location based on
historical wind data  and  dispersion modeling  results.   Downwind stations
can be used  to characterize source  impacts.   Locating downwind  monitoring
locations  at the  source  boundary   Increases  the  potential  for release
detection  and  the characterization  of  onsite exposure  levels.   Downwind
locations  at  the  site  boundary can  be  used  to  estimate  offsite  air
concentration levels.  Offsite  air  monitoring 1s frequently not practical
and should be conducted on an ad hoc basis commensurate with site-specific
project needs.

Determine  Probe Exposure Height

     The  placement of  air monitoring  and  meteorological  stations  must
conform  to  a consistent  set  of  criteria  and  guidance to  ensure  data
comparability and  compatibility.  A detailed set of probe  siting criteria
for  ambient air  monitoring  and meteorological  programs  is  given  in  the
following  EPA document:

     U.S.  EPA, May 1987.   Ambient Monitoring Guidelines  for  Prevention  of
     Significant  Deterioration  (PSD).    EPA-450/4-87/007,  Office   of  A1r
     Quality Planning and Standards.  Research Triangle Park,  NC  27711.

     This document provides  detailed  discussions  and  guidance on probe
 siting criteria.   This section  provides a  summary  of  key  factors  that
 should  bev  considered  as  a  part  of  the  placement  of  an  air   quality
 monitoring station.   The  reader 1s  referred for more details to the above-
 referenced document.
                                    3-57

-------
     Key siting  factors  Include

     •    Vertical  placement  above  ground
     •    Horizontal  spacing  from obstructions and obstacles
     •    Unrestricted air flow
     •    Spacing  from roads

     A summary  of  the  key criteria  associated with  these siting factors
for air  monitoring  stations  1s  included  in Table 3-11.   The  information
Included 1n that table should be used  to  the extent  possible as a part of
the  monitoring  network  design  to  ensure  that  the  monitoring  program
provides  representative  and  unbiased   data.    However,  site-specific
constraints could  make  1t  very difficult  to  meet all  criteria.   For
example, the occurrence  of wooded areas around a  Superfund  site would make
the perimeter siting very difficult, hence  consideration should be given
to the  placement  of stations onsite  and  offsite  to the extent possible.
Therefore,  the  use  of   the   information   1n  Table 3-11,  coupled  with  a
balanced  evaluation  by  an   experienced  air  quality  and  meteorology
specialist is  highly recommended.

     Air emissions  for  most of  the  applications  Involved with Superfund
sites are  from  ground  level  or near-ground-level  releases.   For a site
area  with  no major obstructions  and  obstacles,  the  air  sampler  intake
should be about 2-3 meters aboveground.   For a site with nearby roadways,
however,  Intake placement should  take Into  account the  effects  of road
dust  reentrainment  and  vehicular   emissions.      In  fact,   a   linear
relationship should be  established between the horizontal distance of the
sampler  Intake  from the roadway  and  the  aboveground  elevation  of that
Intake.   For  any roadway  accommodating  more  than 3000 vehicles per day,
the Intake should be between  5  and 25  meters from the  edge  of  the  nearest
traffic  lane.   It  should also be 15 meters  aboveground for a distance of
5 meters  from  the  nearest  traffic  lane  and  2  meters  aboveground  for a
distance of  25  meters  from  the nearest  lane.   For a  roadway  supporting
less  than 3000  vehicles per day, the intake  should be placed at a  distance
                                   3-58

-------
                               TABLE 3-11

   A SUMMARY OF KEY PROBE SITING CRITERIA FOR AIR MONITORING STATIONS
        Factor
                  Criteria
Vertical  spacing above
 [round
Horizontal spacing
from obstruction and
obstacles
Unrestricted airflow
 Spacing from roads
Representative of the breathing zone and
avoiding effects of obstruction, obstacles and
roadway traffic.  Height of probe Intake above
ground Is In general, 2-3m above ground and 2-
15m above ground in the case of nearby
roadways.

About 1 m or more above the structure where
the sampler 1s located.
Minimum horizontal separation from
obstructions such as trees is > 20m from the
drlpHne and 10m from the drlpHne when the
trees act as an obstruction.

Distance from sampler Inlet to an obstacle
such as a building must be at least twice the
height the obstacle protrudes above the
sampler.

If a sampler Is located on a roof or other
structures, there must be a minimum of 2m
separation from walls, parapets, penthouses,
etc.

There must be sufficient separation between
the sampler and a furnace or Incinerator flue.
The separation distance depends on the height
and the nature of the emissions Involved.
Unrestricted airflow must exist In an arc of
at least 270 degrees around the sampler, and
the predominant wind direction for the
monitoring period must be Included 1n the 270
degree arc.
A sufficient separation must exist between  the
sampler and nearby  roadways to avoid the
effect of dust  reentralnment and vehicular
emissions on the measured air concentrations.

Sampler  should  be placed  at a distance of  5-
25m  from  the edge of  the  nearest traffic  lane
on the roadway  depending  on the vertical
placement of the  sampler  inlet which could  be
2-15m above ground.
                                   3-59

-------
greater than 5 meters from  the  edge of the nearest  traffic lane and at a
height of 2-15 meters aboveground.

Determine Program Duration and Sampling Frequency

     The recommendations for program  duration  and frequency of monitoring
are summarized 1n  Table 3-12.   Actual monitoring duration and frequency,
however, will depend on the specific project objectives and resources.   It
1s recommended that  a representative  number  of  air  samples  be collected
during each  step  of the  project  to ensure a  reasonable data  base.   The
number of  representative samples  depends  on  many factors, and  a simple
statistical analysis may  not  provide  a good  basis for this  number.   The
recommendations  specified  in   Table   3-12  are  based  on  the  following
factors:

     •    Frequencies  usually  adopted   in   programs  of   criteria  air
          pollutant monitoring Involving the use  of Integrated samplers  (a
          minimum of one sample  every 6 days for most cases)

     •    Augmentation of  integrated  sampling  with  continuous monitoring
          for steps  that  require  more detailed data to  enhance  the data
          base

     •    The resource  requirements for  laboratory  analysis  for organic
          and Inorganic compounds

     •    Quality   assurance/quality   control    requirements   such    as
          collocated field and trip blank  samples and spike samples

     Samples  taken over  a  very short period  (a minute  or  so)  are not
representative of  average  air  concentrations  of air  toxic  constituents
because  of the high  variability  that could  occur over  short periods  of
time.   For  screening  monitoring,  therefore,  it  is  recommended  that the
samples  taken be  averaged over  at least 15 minutes  and preferably over a
longer period.
                                   3-60

-------
                                                      TABLE  3-12

     PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 1 of 4)
Superfund Step
RI/FS - Screening APA
screening monitoring
refined screening
monitoring
RI/FS - Refined APA
• refined monitoring
Monitoring
Program Duration

• 1-2 days
• same as above

• 4-6 weeks
Frequency
Sampling Duration

• 15-30 minutes at each
sampling location
• 24-hour Integrated

• 24-hour Integrated
No. of Samples

• 20-30 readings using THC
analyzers
• 10-20 samples- using
colorlnetrlc gas detection
tubes or equivalent
• 5-10 samples for organic s 1n
gas phase
• limited QA/QC samples

• 10 at each monitoring
location for organlcs In gas
phase, seal-volatile
organlcs and Inorganics 1n
partlculate phase
• 10 at the collocated
monitoring location for the
same constituents as above
• field and trip blanks*
spiked, split and surrogate
samples on a case-by-case
basis
I
at

-------
                                                 TABLE 3-1?
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUNO PROJECT STEP (Page 2 of 4)
Superfund Step
Remedial Design
• refined monitoring
• refined screening
monitoring
Monitoring
Program Duration

• 3-12 months
depending on
the length of
the pilot
treat ability
study
• same as above
Frequency
Sampling Duration

• 24-hour Integrated
• 24-hour continuous
No. of Samples

• 10-30 at each monitoring
location for organlcs In gas
phase, semi-volatile
organlcs and Inorganics In
partial late phase
• 10-30 at the collocated
monitoring location for the
same constituents as above
• field and trip blanks,
spiked, split and surrogate
samples , on a case-by-case
basis
• continuous at each of the
designated monitoring
locations for organlcs only

-------
                                                 TABLE  3-12
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 3 of 4)
       Superfund  Step
   Monitoring
Program Duration
                                                                         Frequency
                                                     Sampling Duration
                                    No.  of Samples
 Remedial  Action
     refined monitoring
   several
   months to
   more than a
   year
   depending on
   the length of
   the site
   cleanup
   24-hour Integrated
one sample every sixth day
at each sampling location'
for organlcs In gas phase,
semi-volatile organlcs and
Inorganics In partial late
phase
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks.
spikes, split and surrogate
samples, on a case-by-case
basis
     refined screening
     'monitoring
    same as above
•  24-hour continuous
continuous at each of the
designated monitoring
locations for organlcs only
     screening monitoring
    same as above
   24-hour continuous
continuous at each of the
designated monitoring
locations for Inorganics and
total hydrocarbons

-------
                                                     TABLE  3-12
     PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 4 of 4)
            Superfund  Step
   Monitoring
Program Duration
                                                                              Frequency
                                                          Sampling Duration
                                 No. of Samples
      Operation and Maintenance
          refined monitoring
•   Phase I -
    1 year  •
24-hour Integrated
2
one sample every 12th day at
each sampling location for
organlcs In gas phase, semi-
volatile organlcs and
Inorganics In participate
phase
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks.
spiked, split and surrogate.
samples, on a case-by-case
basis
          refined monitoring
    Phase II 2-5
    years
24-hour Integrated
twelve samples per year for
the same constituents as
above
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks on a
case-by-case basis

-------
     The Information presented 1n Table 3-12 provides general guidance and
should be tailored to the specific application.

Select Monitoring Methods and Equipment

     The selection of air monitoring methods and equipment should be based
on the consideration of a number of factors. Including the following:

          Physical and chemical properties of compounds
     •    Relative and absolute concentrations of compounds
     •    Relative Importance of various compounds 1n program objectives
     •    Method performance characteristics
          Potential Interferences present at site
          Time resolution requirements
     •    Cost restraints

     Organic  and  Inorganic  constituents must be monitored by  different
methods.  Within these two groups, different methods may also  be required
depending  on  the  constituent  and   Its   physical/chemical   properties.
Another  condition  that  affects  the  choice  of monitoring technique  1s
whether  the  compound  1s primarily  1n  the  gaseous  phase or  1s  found
adsorbed to solid  particles  or aerosols.

     Screening  for the  presence of  air constituents  Involves techniques
and  equipment  that are  rapid, are  portable, and  can provide  real-time
monitoring  data.   A1r contamination screening  will  generally be  used  to
confirm  the  presence  of  a  release  or  to  establish  the  extent  of
contamination   during   the   screening   phase   of   the   Investigation.
Quantification   of  Individual  components  1s  not  as  Important  during
screening as during  Initial  and  additional  air monitoring;  however,  the
technique must have  sufficient  specificity to  differentiate  hazardous
constituents  of concern from potential Interferences, even when the latter
 are present  1n  higher  concentrations.   Detection limits  are  often higher
 for screening devices than for quantitative methods.
                                    3-65

-------
     Laboratory  analytical  techniques  oust  provide  for  the  positive
Identification of the components  and the accurate and precise measurement
of concentrations.  This generally means that the preconcentratlon and/or
storage of  air samples will  be  required.  Therefore,  methods chosen for
refined monitoring usually Involve a longer  analytical  time period, more
sophisticated equipment, and more rigorous QA procedures.

     The following list of references provides guidance on air monitoring
methodologies:

     U.S. EPA.  June 1983.  Technical Assistance Document for Sampling and
     Analysis  of  Toxic Organic Compounds In Ambient  A1r.   EPA-600/4-83-
     027.    NTIS  PB  83-239020.    Office  of  Research  and Development.
     Research Triangle Park. NC  27711.

     U.S. EPA.  April  1984.  Compendium of Methods for the Determination
     of Toxic Organic Compounds 1n Ambient Air.  EPA-600/4-84-041.  Office
     of Research and Development.   Research Triangle Park, NC  27711.

     U.S.  EPA.     September  1986.     Compendium   of  Methods  for  the
     Determination of Toxic  Organic Compounds 1n Ambient Air.  EPA/600/4-
     87-006.    NTIS  PB87-168696.    Office of  Research  and  Development.
     Research Triangle Park, NC  27711.

     U.S.  EPA.    June  1987.    Compendium  Method  TO-12:    Method  for
     Determination of Non-Methane  Organic Compounds fHMOC) 1n Ambient A1r
     Using   Crvooenlc   Preconcentratlon   and  Direct   Flame  Ion1zat1on
     Detection fPDFIDl.  Research Triangle Park, NC  27711.

     U.S. EPA.  May  1988.   Compendium Method TO-14:  The Determination of
     Volatile  Organic  Compounds   fVOCsl   1n  Ambient   A1r  Uslno   SUMMA*
     Passlvated  Canister   Sampling  and  Gas  Chromatograohlc  Analysis.
     Quality Assurance Division.   Research Triangle Park, NC  27711.
                                   3-66

-------
MIOSH.  February 1984.  NIOSH  Manual  of Analytical Methods.  NTIS PB
85-179016.   National  Institute  for Occupational  Safety and Health.
Cincinnati. OH  45226.

U.S. EPA.  September 1983.  Characterization of Hazardous Waste  Sites
-  A Methods Manual!   Volume  II.  Available Sampling  Methods.    EPA-
600/4-83-040.     NTiS  PB  84-126929.     Office   of  Solid  Waste.
Washington, DC  20460.

U.S. EPA.  September 1983.  Characterization of Hazardous Waste  Sites
-  A Methods  Manual;    Volume  III. Available  Laboratory  Analytical
Methods.   EPA-600/4-83-040.   NTIS  PB 84-126929.    Office of  Solid
Waste.  Washington, DC  20460.

U.S.  EPA.   1986.   Test  Methods  for  Evaluating  Solid Waste.    3rd
Edition.   EPA  SW-846.    GPO  No.  955-001-00000-1.   Office of  Solid
Waste.  Washington, DC  20460.

ASTM.   1982.   Toxic  Materials  1n the Atmosphere.   ASTM, STP  786.
Philadelphia, PA  19103.

ASTM.    1980.    Sampling  and  Analysis  of  Toxic  Organ1cs  1n  the
Atmosphere.  ASTM, STP 721.  Philadelphia. PA  19103.

ASTM.   1974.   Instrumentation for Monitoring  Air Quality.  ASTM,  SP
555.  Philadelphia, PA  19103.

APHA.   1977.   Methods of  A1r Sampling  and Analysis.   American  Public
Health  Association.  Washington. DC 20005.

AC6IH.   1983.   A1r  Sampling Instruments for Evaluation of Atmospheric
Contaminants.     American  Conference  of  Governmental   Industrial
Hyg1en1sts.   Cincinnati,  OH 45211.
                               3-67

-------
     A summary of  air  monitoring method recommendations  as a function of
APA sophistication-level  and Superfund  activity application 1s presented
1n Table 3-13.  These  recommendations  are  based on typical Superfund site
conditions.  Therefore, alternative methods should be carefully considered
and selected on a  case-by-case basis.   A summary of screening methods and
their compound class applicability  1s  presented 1n Table 3-14.  A  listing
of refined  air monitoring methods 1s  Included  1n Table 3-15.  Additional
summaries of these refined methods  and associated equipment are presented
1n Tables  3-16  through 3-22.   A brief  overview of emerging technologies
(e.g.,  mobile  mass  spectrometry  and  laser/Infrared   spectrometry)  1s
presented  1n  Table 3-23.  However, until  these technologies are  further
developed.  1t 1s  recommended  that  standard  air  monitoring  methods  be
selected for Superfund APA applications.

     A bibliography  of standard  operating procedures  for air monitoring
applications 1s presented 1n Appendix  A.  A  11st of  commercially available
equipment  for screening and refined  screening  monitoring  Is presented 1n
Tables 3-24 and  3-25.   Refined monitoring  systems  generally require the
purchase of many  Individual  components.   Therefore, a convenient  summary
of the numerous vendor alternatives 1s not practical for  this document.

3.4.5     Document Air Monitoring Plan

     The site/source-specific air monitoring plan should  be  documented to
facilitate  the  Implementation  of  the  selected monitoring  strategy.    A
recommended procedure for this phase  1s  presented  1n Figure 3-10.

Required Documentation:  Quality Assurance Project Plan

     The EPA requires  of  any project  Involving  environmental measurement—
the  monitoring  for toxic substances of  Superfund  sites,  for Instance—the
preparation of  a  Quality Assurance Project  Plan (QAPP).   The  QAPP,  which
1s  distinct frora  any general project plan,  describes the organization of
the  project and the assignment of responsibility for  those specific QA/QC
activities required  to meet the projet OQOs.   A detailed description of
                                    3-66

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                              TABLE 3-13

           SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS
 Superfund
  Activity
Monitoring Recommendations
      Objectives
II/FS
  Screening
  -  THC analyzers
  -  colorlmetric gas
     detection tubes
                 Refined  Screening
                 -  portable field  GC
                    analyzer
                 Refined
                 -  whole air samplers
                    with GC/MS analysis
                    for Indicator
                    compounds and for an
                    expended 11st (samples
                    split) of compounds
                    (TO-14)
                 -  whole air samplers for
                    volatile organlcs {TO-
                    14)
                 -  1mp1ngers 1f necessary
                    (TO-5. TO-6, TO-8)
                 -  PUT sampling as
                    necessary (TO-9)
                 -  H1-Vol (PM-10) for
                    paniculate matter as
                    necessary (40 CFR 50,
                    Part J)
Determine whether or not
toxic air releases exist
at the site and Its
perimeter using gross
measurement techniques
Obtain qualitative
Information of onslte and
offslte air toxic
concentration for
defining a more refined
monitoring

Support refined
monitoring and provide
near real-time data for
site monitoring

Determine refined levels
of air toxic
concentrations onslte and
at the site perimeter
Utilize these data to
define air monitoring
plan for the next
Superfund step  (1f
necessary)
Assist 1n air quality
data  Interpretation
Determine refined  levels
of toxic air contaminants
onslte. at the  site
perimeter, and  offslte
Utilize results  of the
air monitoring  In risk
assessment for  the no-
action alternative and
evaluating remedial
alternatives
Provide  sufficient
 Information  for the
design  and  Implementation
of  remedial  action-steps
                                  3-69

-------
                               TABLE 3-13

      SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS (Continued)
  Superfund
  Activity
Monitoring Recommendations
      Objectives
Remedial
Design
Remedial
Action
  Refined
  -  Whole air samplers for
     volatile organic (TO-
     14)
  -  1mp1ngers 1f necessary
     (TO-5, TO-6. TO-8)
  .  PUP sampling as
     necessary for seml-
     volatlle organlcs (TO-
     9)
  -  H1-Vols (PM-10) for
     participate matter as
     necessary (40 CFR 50.
     Part J)

  Refined screening
  -  Portable field GC
     analyzer
  Refined
  -  whole air samplers for
     volatile organlcs (TO-
     14)
  -  Implngers as necessary
     (TO-5. TO-6. TO-8)
  -  PUF samplers as
     necessary for sernl-
     volatlle organlcs (TO-
     9)
  -  H1-Vol (PM-10) for
     partleulate matter as
     necessary (40 CFR 50.
     Part J)

  Refined screening
  -  portable field GC
     analyzer
Determine the effects or
pilot treatablllty study
and ambient air quality
and make use of the data
1n the design of the
Implementation of
remedial action step
Support refined
monitoring and provide
near-realtime data for
site monitoring

Provide data 1n support
of protecting public
health and the
environment as well as
onslte workers under
routine and nonroutlne
releases
                                                Provide near-realtime
                                                data 1n support of
                                                protecting public health
                                                and the environment as
                                                well as onslte workers
                                                under routine and
                                                nonroutlne releases
                                   3-70

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                               TABLE 3-13

      SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS (Continued)
  Superfund
  Activity
 Monitoring Recommendations
      Objectives
Remedial
Action
(continued)
Operation
and
Maintenance
   Screening
   -   Electrochemical  alarm
      cells
•  Refined
   -  whole air samplers for
      volatile organlcs (TO-
      14)
   -  1mp1ngers as necessary
      (TO-5. TO-6, TO-8)
   -  PUF  samplers as
      necessary for seml-
      volatlle organlcs (TO-
      9)
   -  H1-Vol (PM-10) for
      part1culate matter as
      necessary (40 CFR 50,
      Part J)
Provide near-realtime
data 1n support of
protecting onslte workers
and sufficient
Information for
protecting public health
and the environment 1n
case of nonroutlne
release

Assess the long-term
effect of the remedial
action on public health
and environment.
                                   3-71

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                                                                     TABLE 3-14


                             SUNNMV OF SCREENING TECHNIQUES fOH DETECTION Of ORGANIC AND INORGANIC CONFOUNDS IN ANUEftT AIR

Compound dm (Ref.Table 3-6)

i. Vplatlle Qjaanlcs
1. Alfpnattcs
'. Aromatic*
1. Halogenated species
4. Oxygenated species
5. Sulfur-containing species
B. Volatile Inoratnlcs
1. Acid eases
2. Sulfur-contiln1«i
c. Sfal-Volatlle Qrqanlcs
1. Phenols
2. Esters
3. ChlortMted benzenes
4. talnes
S. Pesticides Ethers
6. Alkedlenes
7. NlscelUneous illptuttcs
•nd amities
8. Poljnwclear aroHtlc
hydrocarbons
9. PesttclOes
10. Pol/chlorinated blphenjrls
(Ptt's)
b. Non-Volatlles
1. Inoroanlc «eUl$ and non-
Applicable Methods (Ref. Table 3-4)

oiai njarourooii
Analyzers
FID(l)
X

•
«
R
H
II
K
•
M
X

Infrared
*
K
K

X
X
X

ColorlMtrlc Methods
€as
Detection
Tubes
x(?)
X
X
X
X
X
X
X
X
X
X
Continuous
Flow
Colorimeter




Ttpe
Monitor

X


Electrochemical
Detectors and
Alarm

x(HCN)
X

M«9)
Portable (C Analyzers
GC/FID
X
X

X
X
X
XX
X
X

PIO and
GC/PID
xxO)
X

nil)
X

GC/ECD
xx(4)

X
XX
X
X
X
X

GC/FPO
X
XX
X
X


Portable
ta*»
and
Filters

x(5)
X
*
X
X
I
••4
IM

-------
SUWARV'OF SCREENING TECHNIQUES FOR DETECTION OF ORGANIC AND INORGANIC  COMPOUNDS  IN AMBIENT AIR
PAG? 1X0
Abbreviations;
FIO
GC
PID
ECO
FPD
Fine Imitation detector
Gas chrautograph
Pnoto-lonlzatlon detector
Electron capture detector
FtaM photometric detector
Notes;

(I)  FID alone Hill not distinguish between categories of oapounds.  An •«•  In this colon wans that the category «> mured along with all
     other categories.

(*)  Colorlaetrlc gas detection tubes «ay not be applicable to every coapound In a given category.  Consult •enufecturer's Information for
     specific applicability.

(1)  Mhere wre than one GC or total hydrocarbon detector acthod Is listed. '«»• Indicates a preferred acthod.

(4)  As an option for haloglnated species, the  ECO aay be used In conjunction with a Hall detector or PID for anre accurate  Identification of
     compounds.

(5)  Puap/f liter wthods are applicable to partlculate spectes In the Indicated categories.

(6)  Nercaptans My be detected using FID or  Infrared wthods.

 (')  For chlorobenzenes. If a PID Is used. It should be used In conjunction vlth an ECO.

-------
                      TABLE 3-15
          A SUMMARY OF REFINED SAMPLING AND
ANALYSIS TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
I. Organic Compounds:
Traps
• Sorptlon onto Tenax GC
Packed Cartridges using
low volume pump and GC/MS
Analysis
• Sorptlon onto Carbon
Molecular Sieve packed
cartridge using low
volume pump and GC/MS
analyses
• Cryogenic trapping of
analytes 1n the field and
GC/FID or ECO analyses
• Sorptlon onto
polyurethane (PUF) using
low volume or high volume
pump and GC/ECD analysis
• Sorptlon onto
Thermosorb/N packed
cartridges using low
volume pump GC/MS
analysis
• Sorptlon onto PUF using
low volume or high volume
pump and high resolution
Gas Chromatography/H1gh
Resolution Mass
Spectrometry (HRGC/HRMS)
EPA
Method No.


TO-1
TO-2
TO-3
TO-4
TO-7
TO-9
Type of Compounds


• Volatile, nonpolar
organic (e.g., aromatic
hydrocarbons, chlorinated
hydrocarbons) having
boiling points In the
range of 80° to 200°C, 1n
gas or vapor phase.
• Highly volatile, nonpolar
organlcs (e.g., vinyl
chloride, vinyl Idene
chloride, benzene,
toluene) having boiling
points 1n the range of
1-15° to +120DC, In gas or
vapor phase.
• Volatile, nonpolar
organlcs having boiling
points In the range of
-10° to +200'C, In gas or
vapor phase.
• OrganochloHne pesticides
and PCBs, In participate
phase
• N-N1trosod1 methyl ami ne In
gas phase
• 01ox1n
                          3-74

-------
           TABLE 3-15  (Continued)
 A SUMMARY OF REPINED SAMPLING AND ANALYSIS
TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
Whole Air Samplers
• Whole air samples are
collected 1n a SUMMA
passlvated stainless
steel canister and high
resolution GC coupled
with mass specific
spectrometer (GC MS-SIM
or GC-MS-SCAN)
• Whole air samples
extracted directly from
ambient air and analyzed
using cryogenic
preconcentratlon and
direct flame 1on1zat1on
detector (PDFID), or air
samples are collected 1n
a canister and analyzed
by PDFID
• Whole air samples are
collected 1n Tedlar* bags
and subject to GC/FID or
ECD analysis or high
resolution GC compiled
with MS-SIM or MS-SCAN
• Liquid Implngers
• 01n1tropheny1hydraz1ne
Liquid Implnger sampling
using a low volume pump
and High Performance
Liquid Chromatography/UV
analysis
• Aniline liquid Implnger
sampling using a low
volume pump and HPLC
analysis
EPA
Method No.

TO- 14
TO- 12
Modified
TO-3 or
TO- 14

TO-5
TO-6
Type of Compounds

• Volatile, nonpolar
organic (e.g., aromatic
hydrocarbons) chlorinated
hydrocarbons having
boiling points of -30°C
to about 215°C.
• non methane organic
compounds (NMOC)
• TO-14 or TO-3 Compounds

• Aldehydes and Ketones
• Phosgene
                     3-75

-------
           TABLE  3-15  (Continued)
 A SUMMARY OF REFINED SAMPLING AND ANALYSIS
TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
• Sodium Hydroxide Liquid
Implnger sampling using a
low volume pump and HPLC
analysis
II. Inorganic Compounds:
Filter Samplers
• High-volume sampler and
atomic Absorption (AA) or
Inductive Coupled Plasma
(ICP)
• PM-10 high volume sampler
and AA or ICP
• High-volume sampler
• PM-10 high-volume sampler
EPA
Method No.
TO-8


40 CFR Part
50.11
Appendix B
40 CFR
Part 50
Appendix J
(for
sampling
methodology
only)
40 CFR
Part 50.11
40 CFR
Part 50
Appendix J
Type of Compounds
• Cresol /Phenol


Metals 1n part 1cu late phase
Inhalable metals 1n
part 1cu late phase (up to 10
microns 1n diameter)
Total suspended par tlcu late
(TSP)
Inhalable par tlcu late up to
10 microns 1n diameter
                     3-76

-------
                          TABLE 3-16
    SUMURV OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
                     VOLATILE ARONATICSl
Sampling and Analysis Approach
CRYOGENIC PRCCONCENTRATION/GC/F ID/EC -
Vapor Phase organic* are condensed In a
cryogenic trap. Carrier gas transfers
the condensed sample to a GC column.
Adsorbed compounds are eluted from the
GC column and measured by FID or EC
detectors.
CARBON MOLECULAR SIEVE ADSORPTION AND
G/NS or GC/FID - Selected volatile
organic compounds are captured on carbon
molecular sieve adsorbents. Compounds
are thermally desorbed and analyzed by
TENU GC ADSORPTION AND GC/MS OR GC/FID
- Ambient air Is drawn through organic
polymer sorbent where certain compounds
are trapped. The cartridge Is
transferred to the laboratory for
analysis. Using GC/MS or GC/FID.
SUMNA PASSIVATED CANISTER AND GC/FIO/ECO
OR GC/MS - Whole air samples are
collected In an evacuated stainless
steel canister. VOCs are concentrated
In the laboratory with cryogen trap.
VOCs are revotattllzed, separated on a
GC column, and passed to one or mare
detectors for Identification and
Method
Designation
TO-3
TO-?

T0-t<
Detection
Limit
0.1 ppbv
(100 al
sample)
(20 ml
sample)
(20 ml
sample)
0.5-4 ppb

Accuracy'
90-1101
(biased

90-iW
Precisions
115S


tlOT

Advantages
volatile organic compounds
• Standard procedures are
available
• Contaminants common to
adsorbent materials are
avoided
• Low blanks
organic compounds are
collected and concentrated
on sorbent material
• Atmospheric moisture not
collected.
sampled
• Mater vapor Is not
'collected
• Hide variety of compounds
collected
• Standard procedures
available
speclatlon of unknown trace
volatile organtcs
• Staple sampling approach
Disadvantages
cause freezing problems
• Difficult to use In field
• Expensive
organic species are
difficult to recover from
the sorbent.
and certain polar compounds
are not collected.
•MSQTOCfl Q4T OQCQMpOSQ
through Interaction with
container malls
• Condensation may me a
problem at high
concentrations (ppa)
• Complex equipment
preparation required
2 Accuracy'. JTtar^reeMnt9ofTannanalytical measurement with a true or accepted value. Values In this table are expressed as Percent Recovery
3 Precision - The reproduclbimy of repeated measurements of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD-Range/Nean • 100).

-------
                                                                           TABLE 3-17


                                                     SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                                 MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
                                                               VOLATILE HALOGENATED HVDROCARBONSl
Stapling and Analysts Approach
TENAX GC ADSORPTION AND GC/NS OR GC/ECO
- Aablent air Is dram through a
cartridge containing Tenax where certain
volatile organic coapounds are adsorbed.
Compounds are transferred by programed
thermal desorptlon Into a GC and
detected by MS or ECO.
CARBON MOLECULAR SIEVE ADSORPTION AND
GC/NS OR 6C/ECD - Art) lent air Is dram
through a cartridge containing carbon
•olecular sieve mere highly volatile
coapounds are adsorbed. Compounds are
thenMlly desorbed to a GC mere they
are quantitatively Measured using MS or
EC detectors.
CRYOGENIC TRAPPING AND GC/ECO - Vapor
phase organlcs are condensed In a
cryogenic trap. Carrier gas transfers
the condensed staple to a GC coluan.
Adsorbed coapounds are eluted fro» the
GC coluan and deteralned by MS or EC
detectors.
Method
Designation
TO-1
TO-2
TO-3
Detection
LlBlt
.01-1 ppb
1-200 pptv
(20*1
snple)
O.lppbv
(100 •!
sople)
Accuracy?
BO-100X
70-95*
90-1101
Precisions
120*
ilO-40X
tuts

Advantages
• Moisture Is not collected
• Large staple voluae can be
concentrated
• Docwented standard
procedures available with
extensive QA/QC data base
• Practical for field use
• Low detection Halts
• Efficient collection of
polar coapounds
• Hide range of application
• Highly volatile coapounds
arc adsorbed
• Easy to use In field
Large data base
Excellent long-tem storage
Hide applicability
Allows aultlple analyses
Best wthod for broad
speclatlon of unknown VOCs
Easy staple collection
Consistent recoveries
Disadvantages
possible
• Artifact formation probleas
• Rigorous cleanup required
• No possibility of aultlple
analyses
• Low breakthrough voluaes
• Mater collected and can
deactivate adsorption sites
• Theraal desorptlon of
coapounds aay be difficult
• Moisture condensation
• Integrated stapling Is
difficult
CO
    1     See Table 3-6 for listing of analytes.
    2     Accuracy - The Agreeaent of an analytical  aeasureaent with a true or accepted  value.
          (W-Neasured Value/True Value x 100).
    3     Precision - The reproduclblllty of repeated aeasureaents of the
          expressed as Relative Percent Difference (RPD-Range/Nean x 100).
                 Values In this table are expressed as Percent Recovery

property usually aade under prescribed conditions.  Values  In this table are

-------
                                                                           TABLE 3-18
                                                     SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                       MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-VOLATILE OXYGENATES*

Sapling end Analysis Approach
OR GC/PID/EC OR GC/NS - Nhole air
snples ire collected In an evacuated
stainless steel canister. VOCs are
concentrated In the laboratory with
cryogen trap. VOCs are revolatlsed.
separated on a GC column and passed to
one or more detectors for Identification
and quantttatlon
Air sample is drawn through
Dlnltrophenylhydrailne Implnger solution
using a low volume pump. The solution
Is analyied using HPLC with a UV
detector.
Air stream Is drawn through a Tenax
cartridge and adsorbed to It.
Oesorptlon fm Tena« Is by thermal
desorptlon to GC/NS or GC/FID.
Collection of whole air sables In SUMMA
passlvated stainless steel canisters.
VOCs are separated by GC Methods and
•easured by MS or multi-detector
techniques .
See Table 3-6 for listing of analytei
Method
Designation
10- H
TO-3
TO- 5
TO-I
TO-I4
i.
Detection
Limit
U.9-
-------
                                                                       TABLE 3-19
                                                 SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                             MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
                                                                SEMI -VOLATILE PMENOLICSl
Sapling and Analysts Approach
SODIUM HYDROXIDE LIQUID INPIN6ER AND
HPLC/UV - AwJent air It drawn through 2
•Idget taplngers. Phenols arc trapped
as phenolates In NaON solution and
analyzed by HPLC.
ADSORPTION ON TENAX AND GC/FIO OR GC/NS
- AwJent air Is dram organic polywr
sorbent where certain organic compounds
are trapped. The cartridge Is
transferred to the laboratory for
analysis. Compounds are desorbed by
heating.
HIGH VOLUME PUF/TENAX SAMPLER AND GC/ECD
- Sorptlon onto PUF.
Method
Designation
TO-8
TO-1
TO-4
Detection
L1>1t
1 PPb
1.200 ppt
0.2-2
ng/«3
Accuracy?
7S-125X
70-95*
60- lOOf
Precision!
1201
410-40*
t2M

Advantages
• 4.6-d1n1tro-2-wthytphefio1
(SO/1600) specific to class
_• «U^Mu|«
Of COMPOS
• Good stability
• Detect non-volatile as well
•s vo lilt lie CMtpoundt
• Good OA/QC data base
• Hide range of application
• Easy to use In field
• Hide range of application
• Easy to use - low blanks
• Excellent collection and
retention efficiencies
Disadvantages
• Subject to Interferences
• Ltalted sensitivity
• Oesorptlon of sow
cowounds difficult
• Blank contamination
possible
• Artifact formation on
-.-*-nrtia«it
MMII UCIIl
• Nigh hwridlty reduces
collection efficiency
• Possibility of
contamination
1     See Table 3-6 for listing of  analytes.                                                                                     	   	
2     Accuracy - The Agreement of an analytical wasurewnt with a true or accepted value.  Values In this table are expressed as Percent Recovery
      (tt-Neasured Value/True Value x 100).
3     Precision - The reproduclblllty of  repeated wasurewnts of the saw property usually wde under prescribed conditions.   Values  In this table arc
      expressed as Relative Percent Difference (RPO-Range/Nean x 100).

-------
                                                                            TABLE 3-20
                                                       SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                                  MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
                                                               SEMI-VOLATILE BASE/NEUTRAL EXTRACTS!
Sapling and Analysis Approach
HIGH VOL GFF AND PUF FILTERS AND
CC/f 10/tCD OR GC/NS - Partlculates
filtered In field and solvent extracted
In lab. Analyzed by GC/NS.
HIGH VOL. XAD-2 RESIN - Partlculates
filtered fro* art) lent air with low or hi
vol filter. Filters solvent extracted
and analyses completed using GC/NS.
Method
Designation
TO-4
TO-4
(Modifi-
cation)
Detection
Licit
0.2-200
ng/»3
0.2-200
ng/*3
Accuracy?
28-851
80-12M
Precisions
215X
ilSft

Advantages
• Effective for broad range
of compounds
• Easy to preclean and
extract
• Low blanks
• Effective for broad range
of compounds
• Easy to clean
• Broad data base
• Good retention of coapounds
Disadvantages
• Possible contamination
• Loss of volatile organic*
during storage

    1     See Table 3-6 for  listing of analytes.
V  *     Accuracy - The Agreement of an analytical Measurement with a true or accepted value.  Values In this  table are expressed as Percent Recovery
co        (IR'Neasured Value/True Value x  100).
*~  3     Precision - The reproduclblllty  of repeated acasurewnts of the saw property usually Mde under prescribed conditions.  Values In this table are
          expressed as Relative Percent Difference (RPO-Range/Nean x 100).

-------
                                                                 TABLE  3-21
                                           SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                       MONITORING fOR ORGANIC AKD INORGANIC COMPOUNDS IN AMBIENT AIR-
                                                       SEMI-VOLATILE  PESTlCIDES/PCBsl
Sampling and Analysis Approach
HIGH VOL GLASS FIBER AND PUF FILTERS AND
GC/ECD - Participates collected on
filters. Compounds solvent extracted
and analyzed using GC/ECD.
HIGH VOL GLASS FIBER FILTER AND XAD-2
RESIN TO FILTER AND ADSORB PARTICULATES
Method
Designation
TO-4
TO-4
(•Odlfl-
catton)
Detection
LlMlt
0.2-
200 ng/»3
0.2-
200 ng/»3
Accuracy?
28 to
85- 10W
80-12M
Precisions
tlSI
±201

Advantages
Broad range of application
Low blanks
Easy to use
Reusable
High sensitivity
• Can analyze broad range of
compounds (more efficient
than PUT)
Disadvantages
• Can lose volatile co^Kwnds
In storage
• Possibility of
contamination

    1
w  «
k  J
Accuracy6- The Agreeocnt'of an analytical Masureaent with a true or accepted value.  Values In this  table are expressed as Percent Recovery

PrtcU1mT'T£'r^Sc1b!l1i; of°repMted msurements of the saM property usually Mde under prescribed conditions.  Values In this  table are
expressed as Relative Percent  Difference (RPD-Range/Nean x 100).

-------
                                                                         TABLE 3-22

                                                   SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
                                               MONITORING FOR ORGANIC AMD INORGANIC COMPOUNDS IN AMBIENT AIR-
                                                                    VOLATILE  INORGANICS*
CO
Sampling and Analysis Approach
HIGH VOL. GFF AND AA/ICP - Partlculates
are moved fro* air strew with a OFF
or PUT filter, dissolved and analyied by
spectraaetrlc •ettads.
VAPOR PHASE METALS (So. As. Pb. HI. Se.
». Hg) IMPINGCR AND AA/GFA - Collection
vapor phase Ktals on sorbents and In
linger solutions.
VAPOR PHASE CN - NCEF and Sodlui
Hydroxide Liquid liplnger
Method
Designation
TO-4

TO-8/ISP/F.P
A 335.1 or
.3
Detection
Llalt
l-5nq/«3
l-5ng/«3
l-5ng/*3
Accuracy2
IHB^BB^H
125»



Precision'
•••••••••
not



Advantages
Wide range of applications
Standard wthods
low detection 1 lilts
Standard Methods
High sensitivity
QA/QC data base available
Specific acthod for each
actal
• Standard wthods for each
a*tal
Disadvantages

• Possible breakthrough
• High blanks
• Interferences
• Potential Interferences
         klcuI^^Xee^T'or.n^U.l a«.sure*nt with a true or accepted value.  Values In this table are expressed ., Percent Recover,

         Pr^lon'T'TK'rXroducSnit, ."repeated Masurewfts of the saw property usually «*de under prescribed conditions.  Values In this table are
         expressed as Relative Percent Difference (RPO-Range/Mean x 100).

-------
                                                                      TMU 3-?l

                                                  SUMMARY OF SAMPLING MO AMU.YT1CM. KTMDS FOR RCFIMED
                                              MONITORING FOR ORGANIC AND MMCANK COMPOUNDS « AMB1EN1 AIR-
                                                                DEVELOPING TfCHMUKIESl
Stapling and Analysis Approach
MOBILE MAS* SPECTROMTCR (MS/MS,
KS/NS/NS) OR {GC/MS}
LONG PATH FT/lit - RtMte Opt1«l
VoTdtlle [Klsslora Recorder. Uter
tource traftwUUd «cr«t contwfMtH
«rH. Omlte Fourier Trtrnfon nwlytt
of reflected later bew provides organic
contHilMMt uwlysli bj Infrared
fettad
Deilgiutlon
none
(torn
Detect ton
Malt
1 ppb
2«*
Accuracy*


PrecU1on3



Advantages
• Coepoumt tdewllflcattontR
coeylex •!«!*»«$
• Otrect sealing
• field operation
• Direct field MHumiMts
• NlnlM ttw revjulrewit
Oliatf«mta«es
• E>penl*e
• Skilled operator!
• LM sensitivity

u>
09
    Z     Acartcy  - THe A^reeewrt of *n tralyttctl KMurctent wltfc o true «r tccealed vatue.  «alu« tn IM« tab)* w» uqnr«ue4 as Percent fernery

    3     pSc^^Tte'^SStat^Utll J?°reVeol«l «ea«re«nti of U» MM froBerty usually Hde wider prescribed conditions,  tatas l« Mts table
         expressed as Relative Percent Difference (RPO-ftcnee/MHn * 100).

-------
                                                      TABLE 3-24
             TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND
                                                  INORGANICS IN AIR*
Technique
1. THC Analyzers
FIO (Total Hydrocarbon
Analyzer)
Infrared Analysis
2. Colorlmetrlc Gas
detection tubes and
monitors
Gas Detection Tubes
Continuous Flow
Colorimeter
Manufacturers

Beckman
MSA, Inc.
Thermo Electron.
Inc.
Foxboro/W likes

Draeger
Matheson
Kltagawa
CEA Instruments,
Inc.
Compounds
Detected

Most organlcs
Most organlcs

Various organlcs
and Inorganics
Acrylonltrlle,
Formaldehyde,
Phosgene, and
various organlcs
Approximate
Detection Limit

0.5 ppmv
1-10 ppmv

0.1 to 1 ppmv
0.05 to 0.5 ppmv
Comments

Does not respond
uniformly to most
organic compounds on a
carbon basis
Some Inorganic gases
(HzO. CO) will be
detected and therefore
are potential
Interferences.

Highly subject to
Interfernece*
sensitivity and
selectivity highly
dependent on compound
of Interest.
Sensitivity and
selectivity similar to
detector tubes.
00
Ul

-------
                                                TABLE 3-24 (Continued)
             TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND

                                                  INORGANICS IN AIR*
Technique
Colorimetrlc Tape
Monitor
3. Electrochemical
A Urn Cells
4. Portable GC**
Analyzers
GC/FID (portable)
Manufacturers
KHOA Scientific
Foxboro, MSA,
CEA Instruments,
Sensldyne

Foxboro/Century,
Thermo Electron,
Inc.
Compounds
Detected
Toluene.
dllscocyanate,
dlnltro toluene.
phosgene, and
various
Inorganics
Wide range of
Inorganics, also
combustion gases

Most organlcs
except that
polar compounds
may not elute
from the column
Approximate
Detection Limit
0.05-0.5 ppmv
ppmv

0.5 ppbv
Comments
Same as above.
Quantitative
Information for a
single compound by
each cell. Requires
an array of cells.

Qualitative as well as
quantitative
Information obtained,
does not respond
uniformly to organic
compounds.
00
01
        *  Based on Rlggln, 19B3.
        ** Classified as a refined screening technique

-------
                                               TABLE 3-24 (Continued)

             TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND
                                                 INORGANICS IN AIR*
Technique
PIO and GC/PIO
(portable)
GC/ECD (portable)
GC/FPO (portable)
5. Portable pimps and
filters
Manufacturers
HNU, Inc.
Photo vac. Inc.
Therm
Environmental
Instruments Inc.
Thermo Electron.
Inc.
Thermo Electron.
Inc.
Gil Ian
Instrument
Corp., SKC,
Inc.. Mllllpore.
Inc.
Compounds
Detected
Most organic
compounds can be
detected with
the exception of
methane
Halogenated and
nltro-
substltuted
compounds
Sulfur or
phosphorus-
containing
compounds
Inorganics
parttculates and
semi volatile
partlculates
Approximate
Detection Limit
0.1 to 100 ppbv
0.1 to 100 ppbv
10-100 ppbv
100 ppbv-lppmv
Comments
Selectivity can be
adjusted by selection
of lamp energy.
Aromatlcs most readily
detected.
Response varies widely
from compound to
compound.
Both Inorganic and
organic sulfur or
phosphorus compounds
will be detected.
special sorbent plugs
have to be used to
collect semi volat lies
00
        GC means Gas Chromatograph
        FID means Flame Ion1zatIon Detector
        PID means Photolonlzatlon Detector
        ECD means Electron Capture Detector
        FPD means Flame Photometric Detector
        *  Based on Rlgglns. 1983.

-------
                                                                       TABLE 3-25

                                  SUNMRV OF REFINED SCREENING MONITORING EQUIPMENT FOR ORGANIC COMPOUNDS  IN AMBIENT AIR
Sampling and Analysis Approach
centooraoh PC operated portable
f Analyzer utilizing Argon
lottzat Ion/electron capture
detector (ECO) with optional
photolonlzatlon detector.
ireconcentrator and a heated
column with temperature adjustable
to 140'C. Up to 16 different
compounds can be processed at any
,1me. Library Is up to
100 compounds. Ongoing
calibration Is by Injecting
standard calibration gas.





Photovac Model 10S70 portable GC
analyzer utilizing photolonlzatlon
detector (PIO) with a range of
S different energy lamps to
provide selectivity for different
chemical groups. Isothermal oven
control for the multl capillary
colwn. Up to 25 compounds can be
processed at any time. Include
four libraries of 25 compounds
each. Calibration Is by Injecting
standard calibration gas




Manufacturer
Sentex Sensing
Technology, Inc.











Photovac, Inc.










Detection Limit
O.I to several
ppb depending on
the number of
compounds In-
volved and the
•1x











0.1 to several
ppb depending on
the number of
compounds In-
volved and the
•U




.





Precision
about 5- lot,
high
reproduclbllUy











about 5-10*
depending on
compound
Involved, high
reproduclblllty










Mode of
Operation
real tlM
continuous











real time
continuous










Advantages and Disadvantages
Advantages:
• near real time continuous
concentrations of air tonic
constituents
• good accuracy and low detection
limit for a field technique
• eliminates Inaccuracies
associated with the handling of
samples obtained by Integrator
samplers that have to be
shipped for laboratory analysis
• has an option for more than one
detector

Disadvantages:
• can analyze only a limited
number of air toxic
constituents at a time
• subject to Inaccuracies
Introduced by field conditions
and field operators
Advantages:
• Similar to the ones mentioned
above with the exception that
It uses only one detector
Disadvantages:
• Similar to tin ones mentioned
above with the addition of:
- Isothermal oven control Is
up to WC. This GC cannot
operate at higher
temperatures. This reduce
the range of volatile
organlcs that can be
analyzed. Useful mainly for
high volatile organic
- Cannot use detectors other
than the PIO
CO
CO

-------
                                                                  TABLE 3-25(Cont1nued)



                                  SUMMR* OF REFINED SCREW* MONITORING EQUIPMENT FOR ORGANIC COMPOUNDS IN AMBIENT  AIR
Sampling and Analysis Approach
NMI Model 30IOP or 311 portable GC
analyzer. The 301PO aodel can
utilize either a PID or FID and
the 311 aodel can utilise a PIO
only. Includes Isotheraal
uaaerature control of up to JOO'C
for the 301PD aodel and up to
about ZOD'C for the 311 aodel.
Calibrate with either the
coapounds of Interest or with a
reference coapound. Up to
20 coapounds can be processed at
any tl*e.
Manufacturer
HNU Systeas.
Inc.





Detection Limit
0.1 to several
e ssn *
coapounds 1 n-
volved and the





Precision
not readily
available but
expected to be
In the saae
range as -above





Mode of
Operation
real tine
continuous





Advantages and Disadvantages
Advantages:
• Slatlar to the ones above for
the JOIPO aodel
• Slallar to the ones above for
the 311 aodel with the
exception that It uses only one
detector

Disadvantages:
• Slallar to ones listed for the
Scentograph GC
with the addition of
• no teaperature edjustaants
• no library for retention tlaes
co
«o

-------
   MONITORING
  CONSTITUENT
   TARGET LIST
METEOROLOGICAL
   MONITORING
PROGRAM  DESIGN
 AIR MONITORING
NETWORK  DESIGN
   MONITORING
SOPHISTICATION
      LEVEL
     (STEP  2)
                 PREPARE AIR
              MONITORING PLAN
             Project Description
             Project Orcenlzetlon
             Peellltlss/Bqulpmerrt
             Data  Quality Objectives
             Sample Collection
             Sample Cuetody
             Calibration
             Sample Analyala
             Deeumentatlen
             Data  Management
             Internal OO  Oheeka
             external QA Audits
             Prevontatlve Malntena
             Routine Procedures
             Gorreottvo Action
             QA Reports
                        JL
                      PEER
                     REVIEW
                    RPMXEPM
                   APPROVAL
                     INPUT TO      ,
                      4 • CONDUCT
                   MONITORING
    a-10.
                            Plan.
                    3-90

-------
the QAPP 1s given In the following  document:   activities to meet the data
quality objectives for the  project.  Detailed description  of  the QAPP 1s
given  1n  the  EPA document:   U.S.  EPA,  September.  1981.   Preparation of
Quality Assurance Prelect  Plans.    Office  of Toxic  Substances,  Office of
Pesticides and Toxic  Substances.  Washington, DC.   Additional  guidance 1s
available 1n the following:

          U.S. EPA.   1984.  Guide to the Preparation of Quality  Assurance
          Prelect Plans.   Office of Toxic Substances, Office of Pesticides
          and Toxic Substances.  Washington, DC  20460.

          U.S. EPA.   1977.   Quality  Assurance  Handbook for A1r  Pollution
          Measurement  Systems.  Volumes  I  and  II.     EPA-600/9-76-005.
          Office of Research  and  Development.   Research Triangle Park, NC
          27711.

          ASTM.  1988.  Annual Book of Standards?   Part 26. Gaseous  Fuels;
          Coal  and  Coke:   Atmospheric   Analysis.    American  Society  for
          Testing and Materials,  Philadelphia, PA   19103.

          U.S.  EPA.   1987.   Ambient Monitoring Guidelines for  Prevention
          Qf  Significant n^rloratlon  fPSDK   EPA-450/4-87-007.   Research
          Triangle Park.  NC  27711.

          U.S.  EPA.    1987.   Qnslte Meteorological  Program  Guidance for
          Reoulatorv  Mo*»Hna  Applications.  EPA-450/4-87-013.    Research
          Triangle Park, NC  27711.

 Content of  Quality Assurance  Prolect Plan

      The following  1s  a breakdown and  description  of the contents  of  a
 typical QAPP.
                                    3-91

-------
     Project Description.   A general description of the project, Including
the  experimental  design,  must  be provided.    The  description must  be
complete enough to  enable responsible parties  to review  and approve the
proposed plan.  The plan shall  Include the following Items:

     •    Statement  of objectives
     •    Description of the air toxics monitoring program
          Outline  of the sampling method  and frequency of sampling
     •    Outline  of the method of data analysis to be used
     •    Anticipated duration  of the project
     •    Intended use of the acquired data

     Project  Organization  and  Responsibility.   A  11st of  all personnel
assigned  to  data collection,   measurement,  and  verification, Including
brief functional descriptions of their responsibilities, must be prepared.
An organization chart and description of the qualifications of  all project
personnel 1s also recommended.

     Facilities.  Services.  Equipment, and  Supplies.    The utilization of
the resources required for the project must be  considered.  Questions such
as the following should be addressed:

          Can the plan be completed meeting all monitoring requirements In
          a safe manner?

          Are the equipment and  supplies  needed to  complete  the project
          adequate and available 1n sufficient quantities?

          Who maintains and  calibrates the equipment required  to make the
          measurements?

          How frequently 1s the equipment calibrated and serviced?
                                    3-92

-------
         What standards are used to calibrate the equipment?

         Are special  facilities needed to  service or  dispose of  supplies?

     nnn< for  Measurement  Data.  It 1s Important to define the acceptance
limits for data  generated  for the project  to  ensure that  1t  1s complete
and representative of the site.  An attempt should  be made to discuss the
acceptance HmHs  and control factors for sampling  and  analysis errors.
This  Includes  means  for  determining  1f  the  data  generated  meet  the
requirements of the Intended use.
            Collection.   EPA  protocols for  sample collection procedures
should be  referenced  and the  procedures  and equipment to  be  used 1n the
project should be described.   In  addition, a description of equipment and
supplies used  to collect and  transport  samples and of preservatives used
and   holding-time  limitations   should  be   provided.      Record-keeping
procedures must be Included to document pertinent detail.

      Sample Custody.   Procedures  for field sampling operations as  well  as
laboratory operations  are to be provided.   It 1s  critical  to  ensure  that
records  are  adequate  to support  legal documentation  of  the  collection,
preservation,  transport,  and transfer of  samples  for laboratory analysis.

      calibration  Procedures.      The  calibration  procedure   for   each
measurement parameter  should be described, either through reference to the
 standard   operating  procedure   (SOP)   or  through  an  vad  hoc  written
 description.   The  frequency  of calibration  and the frequency with  which
 continuing calibration  1s  verified  also  should  be  described.    The
 standards for  the calibration   and   the acceptable  sources   should  be
 documented.

 Recommended   EPA  documents  that  provide  detailed  Information  on  the
 calibration process are
                                     3-93

-------
     U.S.   EPA,   1987.    Quality  Assurance  Handbook  for  A1r  Pollution
     Measurement Systems.  Volumes I and II.  EPA-60019-76-005.   Office of
     Research and Development.   Research Triangle  Park,  NC  27711.

     U.S.   EPA,  1987.    Ambient  Monitoring Guidelines  for Prevention of
     Significant Deterioration  (PSD).   EPA-450/4-87-007.   Office  of Air
     Quality Planning  and  Standards.   Research  Triangle  Park.  NC  27711.

     U.S.   EPA,   1987.     OnsUe  Meteorological   Program Guidance  for
     Regulatory Modeling Applications.   EPA-450/4-87-013.  Office  of A1r
     Quality Planning  and  Standards.   Research  Triangle  Park,  NC  27711.

Calibration should address

     •    Instrument  flow rate  when  1t  1s  an  Important  component In
          determining  the  concentrations  of air toxic  constituents

          Electronic  zero  and  span  for   analytical  Instruments  such as
          portable  GC  analyzers  and meteorological  equipment  and  known
          calibration  gas, zero, and span for analytical Instruments.

     Laboratory  Analysis   Procedures.    EPA-approved  procedures  for the
monitoring   parameters  should   be  discussed.     Similarly,  a   written
description of the analytical procedures and SOPs that will be  used 1n the
monitoring program should be addressed.

     Data Management.   Data management Includes the procedures  established
to  store  and maintain  both  field  and   laboratory  data  collection and
analysis records.

     Recordkeeo1na/Documentat1on.   The  QAPP  should  specify requirements
for  field  and  laboratory  documents.  For example, the  use  of  logbooks.
forms,  and  other  records of  monitoring/analytical operations should be
Identified.
                                    3-94

-------
     Internal PC  Checks.   The Internal  QC methods  for the  air quality
monitoring project should be described.  Items to be addressed Include

     •    Replicates
     •    Spiked samples
     •    Split samples
     •    Control charts
     •    Blanks
     •    Internal standards
     •    Zero and span gases
     •    Quality control samples
     •    Surrogate samples
     •    Calibration standards and devices
     •    Reagent checks

     External  OA  Audits.    Audits  should  be  scheduled to  verify  that
components  of  the  monitoring program are  In place  and  operating  as
described for both field and laboratory QC procedures.

     Preventive Maintenance.   Preventive maintenance,  Including frequency
and methods  of  Implementation,  should  be  addressed 1n the QA plan.  A list
of  the spare parts  needed  to  ensure  prompt equipment repair and thus  to
minimize downtime  should also be prepared.

     Procedures to Assess Data  Quality.  Specific procedures to assess the
precision  and  accuracy of measurement data  should  be  discussed  In  the
QAPP.    This  Includes  standard  statistical  methods  of evaluating  data
quality.    On  completion  of  testing, the  data can  be reviewed  by  an
 Independent  reviewer to assess  the quality of  the reported values.

     Feedback  and Corrective  Action.    The criteria for acceptable  data
 should be described, as  should the corrective  action to be  taken  1f the
data  quality 1s not acceptable.   The personnel  responsible for reviewing
 the data  and for  Implementing  correction  action should also  be Identified.
                                    3-95

-------
     Quality Assurance  Reports  to Management.    QAPPs  should  provide  a
mechanism for the regular review  of  data quality.  These periodic reports
Include data quality measurements,  performance  and system  audits,  and  a
listing of  measures  taken  to resolve  problems  noted.   Each  of  these
elements should be Included 1n the final  project report.

Review and Approval  of Quality Assurance Project Plan

     A draft of the QAPP should be reviewed by the EPA Project Officer and
the QA Officer  to ensure that the plan  contains the procedures  necessary
to  document  the  prevision,  accuracy,  and  completeness  of   the  data
generated.

     The  draft  should  also  be  subjected  to  a  peer  review—preferably
review by another air expert who was not a primary author of the  plan.  At
the discretion  of the RPM/EPM, this review could be conducted within the
same organization that developed the plan.

     Authority  for final approval  of the plan rests with the RPM/EPM. and
project cost and schedule are major considerations.

3.5       STEP 4 - CONDUCT MONITORING

3.5.1     Overview

     Field and  analytical operations of  the air monitoring  program  should
be  conducted  commensurate  with  the  monitoring  plan  developed  during
Step 3.    However,   successful   Implementation   of the monitoring  plan
requires  adequate field  staff and attention to QA/QC factors.   Therefore,
the  operational approach Illustrated In Figure  3-11 should be applied  to
Superfund air monitoring programs.
                                    3-96

-------
                     MONITORING
                          PLAN
                       (STEP 3)
                      MONITORING
                         STAFF
                   QUALIFICATIONS/
                        TRAINING
METHOD-SPECIFIC
QA/OO CRITERIA
  CAopandlX A)
 SUPIftPUND OAX
PIBLQ OPIRATlOMa
METHODS MANUAL
•AMPUNOX ANALYSIS
 IMVmUMIMTATIOM
   CALIBRATION
 IMPLCMENTAT1ON
   (Figure 3-11)
e OA M«n«g»m«iit
e Sampling  OA
o Analytical OA
o Data  Radueilon
  OA
  TECHNICAL
 ASSISTANCE
  OOOUMBNT
 (Appandlx •)

   OTHER
 TECHNICAL
QC SAMPUNQ/
   ANALYSIS
 FREQUENCIES
  (Tabla 3-28)
                        INPUT TO
                  STEP S - SUMMARIZE
                     AND EVALUATE
                        RESULTS
        «-n.  at«p * • oontftiot
                         3-97

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3.5.2          Field Staff Qualifications and Training

     The air monitoring  program should be designed  and directed by staff
with  air  toxics monitoring  experience.    For many  applications  the site
health and safety officer will be qualified to direct the field monitoring
operations.  However, 1t  should  be  recognized that site health and  safety
officers,  as  well  as staff  with  similar backgrounds  (e.g., Industrial
hyglenlsts), may not  have experience 1n air  toxics  monitoring at the low
detection  levels  (parts  per  billion  or  mlcrograms   per  cubic   meter)
specified  1n  ARARs  to  protect  offsite  receptors.     It  Is  recommended,
therefore,  that  Superfund   air monitoring  projects  be   designed  and
Implemented by  air  quality  specialists  with relevant  ambient air  toxics
monitoring experience.

     It 1s  Imperative that the field staff  who  will be Involved with the
operation   of   the   network   be  trained   personnel   with  sufficient
understanding  of,  and  hands-on  experience  with,   air toxics monitoring
Instrumentation  and laboratory  analysis.   The  field  operators  must  be
sensitive to the overall  aspects of the program Including  but not  limited
to

          In-depth understanding In operating the equipment  Involved.

          Consistent  performance of  the  preventive  maintenance  actions
          recommended by the manufacturer.

          Consistent  performance of  the  routine  tests of  the  equipment
          used to ensure It operates properly.

          Timely Implementation of equipment checks  and calibrations.

          Maintenance of network logbook  and monitoring station  logbooks
          to document  pertinent field  activities.   These  activities  must
          be documented  In a  clear manner  to enable  the use of the logs  as
          needed 1n the  future.
                                    3-98

-------
     •    Careful  handling  of  samples collected to avoid the contamination
          or loss  of materials collected, and  the  documentation In detail
          of every  sample  sent for  laboratory analysis  to maintain  the
          correct  cha1n-of-custody.

     •    Careful   maintenance  of  the  program   sampling  and  analysis
          schedule.
            »
          Careful    checks   of   regenerated   equipment   (traps,   plugs,
          canisters, etc.)  that  are returned by the laboratory.

          Consistent collection  of  QA/QC  samples,  Including  collocated
          blanks.

          Maintenance of open-channel communication with  the site RPM/EPH
          to ensure that he 1s  kept  apprised of any problem area and the
          means of mitigating  it.

     •    Maintenance of open-channel  communication with the  air toxics
          specialist assigned to  the project to expedite the exchange of
          Information that  Is  essential  to smooth  network  operation.

     An Integral part of the  network operation Is the close communication
with  the  laboratory that  has  been  selected to  perform  the  chemical
analysis  on the  samples  collected  In  the  field.   It  1s critical  to
maintain  close   communications   with   the  designated   contact   at  the
laboratory to ensure that

     •    The samples shipped  are received on time.

     •    Analysis 1s performed on time.

          Any  technical Issues  that   develop are  handled promptly  to
          minimize loss of  data.
                                   3-99

-------
     •    Laboratory  results  are  received 1n time for an evaluation of the
          performance  of  the   monitoring  program   and   a  preliminary
          assessment  of, the Implications of the results to the Superfund
          project.

     It Is  clear  from this  discussion that well-trained  field personnel
are the key to a good air toxics  monitoring program.

3.5.3          Quality Assurance/Quality Control

     Quality assurance/quality control topics to be addressed In the QAPP,
required  for Superfund  monitoring  activities,   have  been  Identified 1n
Section 3.4.5.  During the conduct of the air monitoring program, rigorous
conformance to  the QAPP  will be vital  to  meet  project objectives.  Major
QA/QC elements  that  should be  Implemented  during the operational phase of
an air monitoring program (see Table 3-26)  Include

     •    QA management
     •    Sampling QA
          Analytical  QA
     •    Data reduction QA

QA   management   Involves  Implementing  project-specific   administrative
procedures  to control QA/QC  functions.  The  potential for, and types of,
quality  problems  vary  for  the  sampling,  analytical,  and data reduction
functions.     Therefore,  the   QA/QC   requirements   must  be  developed
Individually   for   each   of  these  functions.     Comprehensive   QA/QC
recommendations applicable  to Superfund and air monitoring programs are
available.  Key references Include the  following:

          Superfund  program-specific QA/QC recommendations

          U.S.  EPA March  1986.   Quality Assurance/Field Operations Methods
          Manual.  Draft.
                                   3-100

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                              TABLE 3-26
  QUALITY ASSURANCE  (QA) ACTIVITIES TO BE SPECIFIED  IN  PROGRAM  PLAN
QA Management
   -  QA System Design
   -  Document Control
   -  Data Evaluation
   •  Audit Procedures
   -  Corrective Action
   -  QA Reports to Program Management
   -  Training
Sampling QA
   •  Instrument Calibration and Maintenance
   -  Collection of Routine Quality Control Samples
   -  Data Recording
   •  Sample Labeling, Preservation, Storage and Transport
   -  Cha1n-of-Custody Procedures
Analytical QA
   -  Method Validation Requirements
   -  Instrument Calibration and Maintenance
   -  Quality Control Sample Analysis
   -  Data Recording
Data Reduction QA
   -  Merging Sampling and Analysis Data Files
   -  Storage of Raw and Intermediate Data
   -  Data Validation
                                 3-101

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Generic air toxics monitoring QA/QC recommendations

U.S.  EPA.    June  1983.     Technical   Assistance  Document  for
Sampling and Analysis of Toxic Organic Compounds  1n Ambient A1r.
EPA-600/4-83-027.   NTIS PB  83-239020.   Office  of Research and
Development.  Research Triangle Park, NC 27711.

Monitoring method-specific QA/QC recommendations

U.S.  EPA.     April   1984.     Compendium  of  Methods  for  the
Determination  of  Toxic Organic Compounds  1n Ambient A1r.  EPA-
600/4-84-041.   Office  of Research  and Development.   Research
Triangle Park, NC  27711.

U.S.  EPA.    September 1986.    Compendium  of Methods  for the
Determination  of   Toxic   Organic  Compounds  In  Ambient  A1r.
EPA/600/4-87-006.   NTIS  PB87-168696.    Office  of Research and
Development.   Research Triangle Park, NC 27711.

U.S. EPA.   June  1987.  Compendium Method TO-12:   Method  for the
Determination  of  Non-Methane Organic Compounds fNMOCl  1n  Ambient
A1r Using  Cryogenic  Preconcentratlon and Direct  Flame Inonzatlon
Detection  (PDFIDK  Research Triangle Park,  NC  27711.

U.S.   EPA.    May   1988.     Compendium  Method  TO-14:    The
Determination  of Volatile  Organic  Compounds  fVOCsl 1n  Ambient
A1r   Using   SUMMA*   Pa«1vated   Canister	Sampling—find—Gas
Chromatooraphlc  Analysis.   Quality Assurance Division.   Research
Triangle  Park. NC   27711.

NIOSH.    February  1984.    NIOSH  Manual  of Analytical  Methods.
NTIS  PB 85-179018.    National  Institute of  Occupational  Safety
and Health.   Cincinnati,  OH.
                          3-102

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     •    Meteorological monitoring QA/QC recommendations

         U.S.  EPA.   June  1987.   On-S1te Meteorological  Program Guidance
         for Regulatory Modeling  Applications.   EPA-450/4-87-013.  Office
         of Air Quality  Planning  and Standards.   Research  Triangle Park,
         NC  27711.

     •    A1r quality monitoring QA/QC recommendations

         U.S.  EPA.   February  1983.  Quality Assurance  Handbook  for  A1r
         Pollution  Measurements  Systems;    Volume  IV.    Meteorological
         Measurements.     EPA-600/4-82-060.    Office  of   Research  and
         Development.  Research Triangle  Park.  NC  27711.

         U.S.   EPA.    May  1987.    Ambient  Monitoring  Guidelines  for
         Prevention  of   Significant  Deterioration  fPSDl.    EPA-450/4-
         87/007.  NTIS PB81-153231.   Office of  A1r  Quality Planning and
         Standards.  Research  Triangle  Park, NC  27711.

These  references should   be  consulted  to specify  project-specific QA/QC
requirements based  on  the  approach Illustrated  1n  Figure  3-12.   The
overall QA management system should be Implemented  1n conformance  with the
standard Superfund program approach (U.S.  EPA, March 1986).

     The technical QA recommendations presented 1n On-SUe  Meteorological
Program  Guidance for  Regulatory  Modeling  Applications  (U.S.  EPA, June
1987) and Technical Assistance Document fTADl for  Sampling  and Analysis of
Toxic  Organic  Compounds  In Ambient A1r (U.S.  EPA, June  1983) should also
be  Implemented.   The  calibration  requirements  and  QC  sampling/analysis
frequency  criteria  presented  1n  Tables 3-27  and  3-28,  respectively, are
examples of the  QA recommendations presented In the TAD.

     The  QA criteria  presented  1n monitoring  method-specific  documents
(e.g..  Technical Assistance Document  for Sampling and Analysis  of Toxic
Organic  Compounds In Ambient  A1r.  U.S.  EPA,  June 1983)  Should  also be
                                   3-103

-------
                        IMPLEMENT
                     SUPERPUND FIELD
                  OPERATIONS METHODS
                       MANUAL  - QA
                       MANAGEMENT
                        APPROACH
 IMPLEMENT TECHNICAL
ASSISTANCE DOCUMENT
  (TAD) - TECHNICAL,
 QA RECOMMENDATIONS
    FOR AIR TOXIC
     MONITORING
     (Appendix A)
  IMPLEMENT ON-3ITB
   METBOROLOQICAL
  PROQRAM qUIDANCB
    • TECHNICAL QA
RECOMMENDATIONS FOR
   MBTSOROLOOICAL
     MONITORINQ
 IMPLEMENT  METHOD-
     SPECIFIC QA
  CRITERIA IP MORE
STRINGENT THAN TAD
     (Appendix B)
             IMPLEMENT  SUPPLEMENTAL
            TECHNICAL QA RECOMMEND
             ATIONS  BASED  ON  OTHER
             AVAILABE REFERENCES  AS
                 WARRANTED  IF  NOT
                  ADDRESSED  ABOVE
                       SITE-SPECIFIC
                      AIR MONITORING
                     QA/QC PROGRAM
         3-12. a«jp«rfuod Air Monttortna QA/QC 8tr«t«ay.
                         3-104

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                     TABLE 3-27.  CALIBRATION REQUIREMENTS FOR SAMPLING AND ANALYSIS INSTRUMENTATION
               Device
    Parameter
   Calibrated
     Method of
    Calibration
   Approximate
    Frequency
         Comments
o
Ul
     Sampling Instrumentation
     Sampling pump and
       controller

     Sample volume measurement
       device (usually a dry
       test meter)
     Analytical Instruments
     Continuous monitors
       (e.g.. FID, P1D. FPD.
       etc.)
     Chromatographlc
       Instruments
     Chromatographic
       Instruments

     GC/HS
Flow rate
Total volume
Response
Column
performance and
retention time
for each analyte

Response for
each analyte

Response and
retention time
for each analyte

Mass spectral
resolution and
turning
parameters
Wet or dry test
meter or calibrated
rotameter
Wet test meter
Generation of test
atmosphere of known
concentrations
Injection of
standard using the
same process as for
sample Injection

Same as above
Same as for other
Chromatographlc
Instruments

(a)  Introduction
of perfluoro-
compound directly
Into MS
(b)  injection of
tuning standard
(e.g., brpmofluoro-
benzene) into GC
Meekly
Meekly
Dally or more
frequently if
required
Dally or more
frequently if
required
Same as above
Same as for other
Chromatographlc
Instruments

Dally
Must be determined at
known atmospheric pressure
and temperature.  Flow
rate should be similar to
that used for sampling.


Test atmosphere should be
referenced to a primary
standard (e.g.. NBS
benzene In air).
Flow/pressure conditions
should duplicate sampling
process.
Standard composition
should be checked against
primary standards If
available.

Same as above
Same as for other
Chromatographlc
Instruments

Selection of tuning
standards will be
dependent on type of
analysis being performed.

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  TABLE 3-28.  TYPICAL SAMPLING/ANALYSIS FREQUENCIES FOR QC SAMPLES
          Type of Sample
         Typical  Frequency
Field Blanks

Laboratory Blanks

Spiked Samples
Duplicate (parallel) Samples

Instrument Calibration Standards
Reference Samples
Series (Backup) Samples      	
Each Sample Set; at least 10* of
total number of samples.
Daily; at least 10* of total
number of samples.  Each batch of
samples.
Each sample set; weekly.
10% of total number of samples;
each sample set.
Daily.
Weekly.
Each sample set.           	
                                 3-106

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Implemented  1f  these  QA  recommendations  are more  stringent  than  those
stipulated 1n the TAD.

     Supplemented technical  QA recommendations  based on  other available
references (e.g., Quality Assurance Handbook for Air Pollution Measurement
Systems. U.S. EPA, February  1983)  should  also be implemented as warranted
for factors not addressed in the previous documents.

3.6       STEP 5 - SUMMARIZE AND EVALUATE RESULTS

3.6.1     Overview

     Monitoring  data  available  from  Step  4  should  be  summarized  and
evaluated  to  provide   input  to  site-specific  risk assessments  and  the
Superfund  decision-making  process.    The  recommended   data  processing
approach  1s  illustrated  1n  Figure 3-13.   This  approach consists of  the
following  major  elements:

           Validate data
      •     Summarize  data
           Model  dispersion to  extrapolate  monitoring data

      Raw monitoring data  should be  checked  for validity  before  they are
 used as a part  of the data  base for  site decision-making.  These validity
 checks  are  an  integral  part   of   the   QA/QC  program  for  monitoring
 activities.

      The  validated data  set  should  be  further  processed   to  provide
 meteorological  and  air concentration  summaries.   Meteorological  data are
 also used to  classify the upwind/downwind (relative to the Superfund air
 emission  source)  exposure  conditions   associated with   air  monitoring
 results.  The validated data  should  be processed  to obtain sequential  data
 listings  as well as statistical summaries.
                                    3-107

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                      INPUT DATA
                         FROM
                        STEP  4
                            1
                    VALIDATE DATA

               o Mataorologloal Monitoring
               o Air Monitoring
                  SUMMARIZE DATA

               o Data  Listings
               o Statistical  Summarise
     METEOROLOQIOAL
        SUMMARIES
AIR MONITORING
   SUMMARIES
                     DISPERSION
                   MODELING  TO
                         DATA
                           T
                       INPUT TO
                      SUPERFUND
                  RISK ASSESSMENT/
                   DECISION  MAKING
Figure 3-13.  Stop 8 - aummariza and Evaluate Neaulta.
                         3-108

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     Dispersion  modeling  may  be  warranted   for  certain  situations  to
supplement air  monitoring  results.    For example,  1t  may  be  useful  to
extrapolate site boundary.monitoring results to offslte  receptor locations
of interest.

     Each of these topics 1s discussed  1n greater detail 1n the following
subsections.

3.6.2     Validate Data

     Data  validation  1s   an   important  QA/QC  component  of  Superfund
monitoring  programs.    For  Superfund  APA   applications,  this  usually
Involves  a combination of automated checks  during computer processing of
the raw data as well as manual review of the data by an  air specialist.

Meteorological Data Validation

     Raw  meteorological  data   should  be  checked   for  validity   using
equipment   calibration,   audit,   and   performance    data.   Comprehensive
technical  recommendations for meteorological data validation  presented  in
the following reference should be adopted  for  Superfund  APAs:

      U.S. EPA,  June 1987.   Qn-Slte Meteorological  Program  Guidance
      for  Regulatory   Modeling  Applications.     EPA-450/4-87-013.
      Office  of  A1r  Quality  Planning   and  Standards.    Research
      Triangle  Park, NC   27711.

Table  3-29  presents meteorological  data screening  criteria.   It  is  an
example  of the technical  data validation  recommendations  presented  in the
reference cited above.
                                    3-109

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    TABLE 3-29.   SUGGESTED  METEOROLOGICAL  DATA SCREENING CRITERIA*
                        (U.S. EPA, JUNE 1987)
 Meteorological
    Variable
                Screening Criteria*
Wind Speed
Flag the data 1f the value:

   1s less than zero or greater than 25 m/s
   does not vary by more than 0.1 m/s for 3
   consecutive hours
   does not vary by more than 0.5 m/s for 12
   consecutive hours
Wind Direction
   1s less than zero or greater than 360 degrees
   does not vary by more than 1 degree for more than
   3 consecutive hours
   does not vary by more than 10 degrees for 18
   consecutive hours
Temperature
   1s greater than the local record high
   1s less than the local record low
   (The above limits could be applied on a monthly
   basis.)
   1s greater than a 5°C change from the previous
   hour
   does not vary by more than 0.5°C for 12
   consecutive hours
Temperature
Difference
    1s greater than 0.1°C/m during  the daytime
    1s less than -0.1°C/m during the  nighttime
    1s greater than 5.0°C/m or  less than  -3.0°C/m
 Dew  Point
 Temperature
    1s greater than the ambient temperature  for the
    given  time period
    1s greater than a  5°C  change  for  the  previous
    hour
    does not  vary  by more  than 0.5°C  for  12
    consecutive  hours
    equals the ambient temperature for 12 consecutive
    hours
 Precipitation
    1s greater  than 25 mm in one hour
    1s greater  than 100 mm 1n 24 hours
    1s less than 50 mm in three months
    (The above  values can be adjusted based on local
    climate.)                     	
                                 3-110

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    TABLE 3-29.
SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA*
  (U.S.  EPA.  JUNE  1987)  (Continued)
Meteorological
Variable
Pressure
Screening Criteria*
• Is greater than 1060 mb (sea level)
• 1s less than 940 mb (sea level)
(The above values should be adjusted for
elevations other than sea level.)
• changes by more than 6 mb 1n three hours
a  Some criteria may have to be changed  for a given location.
                                  3-111

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Air Monitoring Data Validation

     A1r  monitoring  data  should  also  be  validated  utilizing equipment
calibration,  audit,  and  performance data  in  a manner  similar  to% that
recommended for meteorological data.

     Analytical  results  should  be  subject  to  a   thorough  validation
process.   This process  requires the use  of  a  qualified  chemist who  is
familiar with the data validation requirements and process.   Validation  of
analytical results for one  sample  could  take from 15  minutes to more than
an  hour,  depending  on  the type  of analysis,  the  number  of  air toxic
constituents involved, Interference, contamination, and other factors.

     Raw  air quality data  received  from  portable GC analyzers  or other
continuous   Instruments   should  also   be   checked  for  validity.    The
performance  of  the  analyzer,  calibration,  and  QA  results   should   be
considered.

     Air  monitoring  data  validation  efforts  should include  evaluating
collocated  station  results  and  audit results to determine  data  precision
and accuracy, as follows:

          The  percent  difference between  the air concentrations  measured
          at coal located  samplers  is
                         di  =    Y1 " X1    x 100                     (3-5)
           where
                     the  percent  difference between  the  concentration  of
                     air  toxic constituents  YI  measured  by  the collocated
                     monitoring  station and the  concentration of air toxic
                                    3-112

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          constituent  XL  measured  by  the  monitoring  station
          reporting the air quality

The average percent difference dj for the monitoring period Is
                     n
 n
 £
1=1
                                                            (3-6)
where
d-|   =    percent difference defined above

n    =    number  of  samples  collected  during  the  monitoring
          period

The standard deviation Sj for the percent differences  1s
 1
n-1
n
£
                                                  1/2
                                  (3-7)
The 95-percent probability limits for precision are

Upper 95-Percent Probability Limit = dj+1.96 SJ//2      (3-8)
Lower 95-Percent Probability Limit = dj-1.96 SJ//2      (3-9)

The  accuracy   1s   calculated  for  the  monitoring   period  by
calculating  the  percent  difference di  between  the  Indicated
parameter  from the  audit  (concentration,  flow  rate, etc.)  and
the known parameter, as follows:
                         3-113

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                                   "       x 100                    (3-10)
                                   X1
          where

          YI   =    monitor's  Indicated parameter  from the Hh  audit  check

          Xi   =    known parameter used for  the  1th  audit check

     These  results   should  then  be  compared  with   the QA/QC  criteria
stipulated 1n the monitoring plan  to  determine data validity.

3.6.3     Summarize Data

     Monitoring  data  summaries should be prepared using the  validated data
bases as  Input.   These meteorological  and  air  monitoring data summaries
facilitate the characterization of exposure  potential  at  various locations
and receptors of Interest.

Meteorological Data Summaries

     Meteorological   data  summaries  should   Include   the  following  at a
minimum:

          Listing of  all  meteorological  parameters   for  the air  sampling
          periods

          Daytime wind rose (only for coastal or complex  terrain areas)

          Nighttime wind rose (only for coastal or complex terrain areas)
                                   3-114

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    •    Summary wind rose

         Summary of  dispersion  conditions for the  sampling  period  (joint
         frequency  distributions  of  wind  direction  versus  wind  speed
         category  and  stability  class  frequencies  based  on  guidance
         presented  1n Guidelines  on A1r Quality  Models  (Revised)  (U.S.
         EPA, July 1986)

     •    Tabular  summaries  of   means  and  extremes for  temperature  and
         other meteorological parameters

         Data recovery  summaries for all  parameters

     Meteorological  listings should generally be presented on a sequential
hourly basis.  A 1-hour time frame is sufficient to account  for any short-
term temporal  variability  of  the  data.    The  presentation of  data for
periods of  less  than 1 hour would unduly  complicate  the data evaluation
process, and the  listings  would be voluminous.  For  those cases 1n  which
multiple  meteorological  stations  are  used  at  a single  site,   it   is
desirable  to  11st  the  data   in  adjacent  columns   to  facilitate  data
comparisons.

     Statistical summaries for the meteorological  data should  be  presented
monthly, seasonally,  and  annually,  and  for the entire  monitoring  period.
For  sites with  diurnal  wind patterns (e.g., at  complex  terrain or  coastal
areas),  separate wind  roses  should be prepared  to   characterize  daytime
conditions  and nighttime conditions, and  a  summary wind  rose (based on  all
wind  observations during  the monitoring period)  should be developed.  A
suggested format  for  wind  rose data  is  illustrated in  Figure 3-14.

     Data  recovery Information  should  also be  presented to allow  for  an
evaluation  of data representativeness.   The minimum  data recovery target
should be  75 percent.
                                    3-115

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        WIND  OZRECTZON  FREQUENCY   (PERCENT)
        MEAN  WIND   SPEED   (MZ/HR  )
Figure 3-14 Example Wind Rose Format
                            3-116

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A1r Monitoring Data Summaries

     A1r monitoring  data  summaries  should   Include  the  following  at  a
minimum:

     •    A listing of  concentrations measured by  station and monitoring
          period Indicating  concentrations  of all  constituents  for which
          monitoring  was  conducted.     The   listings  should  Indicate
          detection limits for  those  cases  1n which  a  constituent  1s not
          detected, as well as upwind/downwind exposure classification and
          monitoring station operational data  (e.g.,  sampling flow rates,
          station numbers, sampling start/end times);

     •    Summary  tables  of  constituent-specific  concentrations measured
          for each monitoring station, Including the following:

               Mean concentration

               Minimum concentration

               Maximum concentration

               Detection limit

               Frequency above and below detection limits

               Number of samples

               Number  of  occurrences  of  air  concentrations   exceeding
               selected values  (e.g.,  health  and  safety  criteria,  ARARs
               and odor thresholds)

               Upwind/downwind exposure summaries
                                   3-117

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     •    A  narrative discussion of sampling  results,  Indicating problems
         encountered,  the relationship of  the sampling  activity  to unit
         operating   conditions  and  meteorological  conditions,  sampling
         periods  and  times,  background  levels  and  other air  emission
         sources,    and   interferences   that    may    complicate   data
         interpretation

     •    Data recovery parameters  for  all parameters

     A1r monitoring listings should be  sequential  and  consistent with the
sampling interval  used (e.g.,  one 24-hour Integrated sample to represent a
1-day period  1s  frequently used).  The listings  should  include flags to
identify samples  that exceed  health/safety  criteria,  ARARs,  and  odor
thresholds.    Monitoring  station  operational  data  (e.g.,  start  and stop
times for sampling,  sampling flow  rates)  should  also be included with the
data listings.   If  practical,  concurrent data for the monitoring network
(I.e..  all   stations)  should be  listed  1n adjacent  columns to  facilitate
data comparisons.

     The  air  monitoring  data  listings   should   also   indicate  the
upwind/downwind  classification  of  the  monitoring   station  during  the
sampling period.  Based on hourly meteorological data, the percentages of
the  sampling  time  that  a  station  1s  upwind  and  downwind  should be
specified.    Therefore,  upwind and  downwind  sectors (I.e., a range of  wind
directions)  should  be defined  for each monitoring station  to aid 1n  data
Interpretation.  Figure  3-15 exemplifies the  range of  wind  directions  over
which  the  air monitoring stations will  be  downwind  of an  air  emission
source.  Therefore, concentrations measured  during upwind conditions can
be used  to characterize background conditions, and concentrations  measured
during  downwind  conditions can be used  to  evaluate  the  source-specific
contributions  to downwind  exposures.

     Plotting  Individual  concentration points as  a function of  downwind
frequency  can Improve  the  interpretation of  data  for  certain situations.
Such analyses are generally beneficial for sites  with significant diurnal
                                   3-118

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                                               UNIT SOURCE
      MONITOR ING STATIONS





      DOWNWIND SECTOR
Figure 3-15. Example of Downxlnd Exposures at A1r Monitoring Stations
                           3-119

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wind direction  variability, especially  those on  complex terrain  and in
coastal  locations.   An  application of  this downwind  frequency analysis
approach 1s Illustrated in Figure 3-16.  Examination of  the data presented
in this  figure  Indicates  that  air concentrations  at  Station  A are random
and not correlated with downwind frequency.  However, the data for Station
B appear to be  linearly related  to  downwind frequency.   Therefore, it can
be concluded that the  air  emission  source significantly affects Station B
but not Station A.

     Statistical  summaries of  air  monitoring  data  should  be  presented
monthly, seasonally, and  annually,  and for  the  entire monitoring period.
In addition  to concentration means  and extremes,  these summaries should
present  any  other  information   deemed  useful for the  interpretation of
monitoring results.  Of particular interest, for example, is  the frequency
that sampling  results  are  below (or above)  analytical  detection limits.
Samples  that  are  below  detection  limits  can   greatly complicate the
computation of mean concentrations.  Therefore, in  the computation of mean
concentrations  for  a  Superfund  APA  application,  concentrations  for any
sampling period  that  are less than  the  lower analytical detection  limits
should  arbitrarily  be  assumed to  be one-half the lower detection  limit.
In  the same  connection,  concentrations  that  exceed the upper detection
limits  should arbitrarily be assumed to be equal to the  detection limit.

     Air  monitoring data  summaries  should  also  indicate  the  number of
occurrences  of  air concentrations  that  exceed  health/safety criteria,
ARARs,  and odor  thresholds.   Upwind/downwind  exposure conditions  should
also be addressed 1n  these summaries.  Therefore,  concentration means and
extremes for each station  should be presented for  the following data  sets:

          All samples

          Samples that are predominantly  (i.e.,  greater than 75  percent)
          downwind
                                   3-120

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i
»-•
ro
         i
         •->
         Ok


         7


        I
                  24-HOUR

            CONCENTRATION (ppb)



                 100-r-
        o


        o
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        in
                                                 KEY:


                                                A  » STATION A


                                                • = STATION B
                                               60

                                      DOWNWIND FREQUENCY
                                                          100

-------
     •    Samples which are predominantly  (I.e.,  greater than 75 percent)
          upwind

     Data recovery  Information  should  also be  presented to evaluate data
representativeness.  A minimum data recovery target should be 75 percent.

3.6.4     Perform Dispersion Modeling

     Results of  atmospheric  dispersion modeling can be  used to assist  in
the interpretation  of  the  air monitoring results.   They also can be used
to augment the measured data.

     Dispersion   patterns   derived   by   plotting   isopleths  of   air
concentration divided  by  the source emission  rate for the  air monitoring
periods can provide Information on areas of high  concentrations and  zones
of concentration gradients.   Comparison of these patterns with measured
concentrations   can  provide  additional   Information  on   areas  of  high
concentration  and  a  qualitative  Interpolation and extrapolation  of the
pattern of the measured concentrations.

      Frequently  1t may not be  practical  to place air monitoring  stations
at offslte  receptor locations of  Interest.   However,  it may  be  necessary
to  characterize  concentrations  at these locations  as   Input  to  site-
specific  risk  assessments.   In  these  cases,  dispersion patterns based  on
modeling  results  can  be  used to  extrapolate  concentrations  monitored
onsite   to   offslte  locations.    An  example  of  this   application   1s
Illustrated  in  Figure  3-17.

      Technical   recommendations   regarding   the   conduct   of  dispersion
modeling  studies (e.g., model  selection)  are provided  1n Section  2.
                                    3-122

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    ATMOSPHERIC DILUTION PATTERN
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-------
3.7  EXAMPLE APPLICATION

     A  screening  assessment  (based  on  emission/dispersion  modeling)  1n
accordance  with  Volume  I  recommendations  was conducted  to characterize
hazardous air constituents being  released  from an inactive wood treatment
facility that had  been placed on the  NPL.   Evaluation of these screening
results indicated that 1t was necessary to  conduct a monitoring program to
more   accurately   quantify   air  emissions   from  the  site  to   support
preparation of an RI/FS.

Collect and Review Information

     ~he site 1s an  Inactive 12-acre wood treatment facility located in a
flat  Inland area of  the Southeast.   Creosote and pentachlorophenol were
used  as wood preservatives;  heavy  metal  salts had  also been used  1n  the
past.   Creosote  and  pentachlorophenol  were  disposed  of  1n  a  surface
Impoundment.   Past  waste disposal  practices  Included  the treatment  and
disposal of the  metal salts 1n a surface  Impoundment,  and the  disposal  of
contaminated wood  shavings  1n waste piles.   The constituents of concern 1n
the  facility's  waste  stream  Include phenols,  cresols,  and  polycycllc
aromatic   hydrocarbons   (PAHs)   1n   the   creosote;   d1benzod1ox1ns   and
dlbenzofurans  as contaminants 1n pentachlorophenol;  and partlculate heavy
metals.    The   potential   emission  sources  (Figure  3-18)  Include  the
container  storage facility  for creosote  and pentachlorophenol;  the  wood
treatment   and  product  storage  areas;  the  surface  impoundment   for  the
creosote  and  pentachlorophenol  wastes;  and  the contaminated  soil area,
which previously contained  both  the surface  Impoundment  for treating  the
metal  salts and the wood shavings  storage  area.   Seepage from these waste
management units has resulted 1n documented groundwater and surface water
 contamination.

      The  area  surrounding  the   facility  has  experienced  substantial
 development over  the years.   A shopping  center  is  now  adjacent to  the
 eastern site perimeter.  This  development has significantly increased the
 number of potential  receptors of air releases of hazardous constituents.
                                    3-124

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          SURFACE
  IMPOUNDMENT AND
  CONTAMINATED
  WOOO SHAVINQ9
  STORAGE AREA
 ACMTIO
 SUflFACt
    OFFICE Q
          CONTAINER
          STORAGE
          FACILITY
              -H—
               GATE
       PREVA1UNO

       WIND
       DIRECTION
ft
Figure 3-18 Example Site  Plan and A1r Monitoring Network
                       3-125

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     To develop an adequate  monitoring program, the composition of wastes
handled  1n  each waste  management unit  was first  determined  to  identify
which  constituents  were  likely  to  be  present  in  the  air  releases.
Existing  water quality  data Indicated  the contamination of groundwater
with cresols, phenol, and PAHs and of  surface water with  phenols,  benzene,
chlorobenzene,  and ethylbenzene.   A field  sampling program was developed
to further  characterize the facility's  waste  stream.  Wastewater samples
were collected from the aerated surface  impoundment,  and  soil  samples were
collected  from  the  heavy  metal   salt waste  treatment/disposal  area.
Analytical  data from this  sampling  effort confirmed  the presence of  the
constituents  previously  identified.    Additional   constituents  detected
include  toluene and  xylenes  in  surface  impoundment  wastes,  and  arsenic,
copper, chromium, and zinc in the treatment/disposal  area.

Select Monitoring Sophistication Level

     A limited onsite air screening  survey  was  first  conducted to  document
air  releases  of potentially hazardous constituents, to  assign  priorities
to  air  emission sources,  and  to  verify screening assessment  modeling
results  and the need to conduct  a monitoring  program.   Total hydrocarbon
(THC)  levels  were measured  with  a  portable  THC analyzer downwind of  the
aerated  surface  Impoundment,  wood  treatment  area,  and product  storage
area.    Measurements  were  also  made  upwind   of  all  units  to  provide
background  concentrations.     The  THC  levels detected  downwind   were
significantly   higher   than  background  levels.    However,  constituent-
specific  results  were  not  available  from  this  screening  approach  to
quantify  the  potential health  and  safety  impacts  associated with  air
emissions from  the  site.   Therefore,  a  refined  monitoring  program  to
characterize releases to the air was considered appropriate.

Develop  Monitoring Plan

      Based  on  their Individual  emission  potentials (as  determined  from
waste analyses and confirmatory  emission rate modeling) and potentials for
                                    3-126

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presenting health  and environmental  hazards, the  following constituents
were selected for measurement In the air monitoring program:

     •    VolatHe/semlvolatile constituents

               Toluene
               Benzene
               Total phenols
               Pentachlorophenol
               Polycycllc aromatic hydrocarbons
               Cresols

     •    Participate constituents

               Arsenic
               Copper
               Chromium
               Zinc

     Meteorological   Information   1s   critical   for   designing   an  air
monitoring  program  because  stations   must  be  located  both  upwind  and
downwind of  the  contaminant sources.   Therefore, a  1-month  meteorological
monitoring survey was conducted at this flat-terrain site.   The survey was
conducted under  conditions  considered  representative of the summer months
during  which air  samples  would  be  collected.   Summer  represented  the
worst-case combination of emission and  dispersion conditions (I.e., light,
steady  winds and warm temperatures).   The  collected meteorological data
showed  that  the local wind direction  was  from the  southwest.   No well-
defined  secondary  wind  flows  were  identified.    The  survey data  also
confirmed that one  10-meter meteorological  station would be sufficient to
support the  air monitoring program.

     The  onslte meteorological survey data  were  used  with  the EPA's,
Industrial Source  Complex  (ISC)  dispersion model  to estimate the worst-
case  air  emission concentrations  and  to help  determine  the locations of
                                   3-127

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the air sampling  stations.   The ISC dispersion  model  was used because of
its capability  to simulate  conditions of  point and  nonpoint source air
emissions and because of  recommendations  made in Chapter 2.   Allowing for
the established southwest wind  direction, maximum downwind concentrations
were  predicted  for different  meteorological  conditions  (e.g., different
wind  speeds).   The selection  of upwind  background  stations   and downwind
monitoring  stations  was  based  on  the   predicted   dispersion pathways.
Because  the releases  from  the Individual  source areas  overlapped, the
model  also  provided a  means of  identifying  the  contamination from  each
source.

      Figure  3-18  shows the  locations of  the selected sampling stations.
Station  1  was  selected  as the  upwind  background   station.    Background
volatile    organic   concentrations,    partlculate   concentrations,   and
meteorological conditions were  monitored  at this station.  Stations  2 and
4  were  located  at points convenient  for  the  monitoring  of  volatile
emissions from  the  surface  impoundment and  wood treatment/product  storage
areas,  respectively.    Station 3  was located  downwind  of   the  Inactive
surface  Impoundment/wood  shavings disposal  area.    Releases from  these
sources and worst-case  concentrations  of  volatlles and partlculates at the
site   property   boundary  were  documented   at   this  site.    For   this
application,  the  locations of  Stations   2,  3,   and  4  were   adequate  for
characterizing  the  air concentrations at  both the source boundary  and the
site  property boundary  (due to the proximity of these  two  boundaries  in
the  downwind direction  of  the  units  of  concern  for the  site prevailing
wind  direction).   Three  trailer-mounted  air monitoring  stations were used
to supplement the permanent stations  and  to account for any variability 1n
wind  direction.

      Several alternative methods  were  considered for  air  monitoring  at
this  site.   It was decided  to use EPA  Method  TO-14  (whole air  sampling
using metal  canisters)  for benzene  and  toluene.  A modified high-volume
 sampler consisting of a glass fiber filter  with a polyurethane foam backup
 sorbent  (EPA Method  TO-4)  was  selected  to sample  for total  phenols,
 pentachlorophenol,  and  PAHs.    NIOSH Method  2001,  which  involves  use  of
                                    3-128

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silica  gel  cartridges, was  selected for  the collection  and  analysis of
cresol  samples.   Particulates  were collected on glass fiber filters using
high-volume samplers.

Conduct Monitoring

     The air quality monitoring was conducted over a 3-month period during
the   summer.      Meteorological   variables  were   measured  continuously
throughout the study.  A1r  samples were taken over a 24-hour period every
six days.  A  rigorous  QA/QC program was Implemented commensurate with the
selected monitoring  period  and according  to the method  specified  1n EPA
technical  reference  documents.    Field technicians  assigned  to conduct
multimedia environmental  surveys  for the  RI/FS and  to operate  the air
monitoring network.   These staff were trained by an air toxics  specialist.
The air toxics  specialist also routinely  reviewed  the monitoring results
to evaluate data  validity,  to  Identify potential monitoring problems, and
to  determine  the need  for corrective action.    He  was  assisted  by  a
chemist, who  performed the  detailed data  validation  for  the  air toxics
under consideration.

Summarize and Evaluate Results

     Standard  sampling/analytical  methods  were  available for all  the
target monitoring constituents.  However, analytical detection  limits were
below  specific  health  and  environmental   criteria  for  all  constituents
except  cresol.    The  high analytical  detection  limit   for   cresol—it
exceeded  reference   health  criteria—complicated  data   analysis.    This
difficulty was handled by the  collection and analysis of additional waste
samples.   The data obtained 1n these  analyses  were subjected to emission
rate modeling to  determine the emission potential of cresol  and thus to
develop an estimate  of cresol levels 1n the air.

     Analytical  results obtained  during this sampling program  established
that  fugitive  air  emissions  significantly  exceeded  reference  health
                                   3-129

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criteria.   Measures to  reduce emission  concentrations  to a  point below
health criteria levels were Identified.
                                    3-130

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                              4.0 REFERENCES
ASTM.   Annual  Book of  Standards  (published annually).   Part 26, Gaseous
Fuels; Coal and Coke; Atmospheric  Analysis.  American Society for Testing
and Materials, Philadelphia, PA.

U.S. EPA.  March 1986.  Quality Assurance/Field Operations Methods Manual.
Draft.

U.S.  EPA.   June  1983.    Technical Assistance  Document  for  Sampling and
Analysis of  Toxic Organic  Compounds  1n  Ambient  A1r.    EPA-600/4-83-027.
NTIS PB 83-239020.  Office of Research and  Development.   Research Triangle
Park, NC  27711.

U.S.  EPA.   April  1984.   Compendium  of  Methods for  the Determination of
Toxic  Organic Compounds  1n Ambient  A1r.   EPA-600/4-84-041.   Office of
Research and Development.  Research Triangle Park, NC  27711.

NIOSH.   February  1984.   NIOSH Manual  of  Analytical  Methods.   NTIS PB 85-
179018.     National   Institute   of   Occupational   Safety   and  Health.
Cincinnati, OH.

U.S.  EPA.    June  1987.    On-S1te  Meteorological  Program  Guidance for
Regulatory  Modeling  Applications.    EPA-450/4-87-013.    Office of A1r
Quality Planning and Standards.  Research Triangle Park,  NC   27711.
                                    4-1

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U.S. EPA.   February 1983..  Quality Assurance Handbook  for Air Pollution
Measurements Systems:  Volume IV. Meteorological Measurements.  EPA-600/4-
82-060.  Office  of Research and Development.  Research  Triangle  Park, NC
27711.

U.S. EPA.  November 1980.  Ambient Monitoring Guidelines for Prevention of
Significant Deterioration  fPSDK   EPA-450/4-80/012.   NTIS  PB 81-153231.
Office of A1r Quality  Planning  and  Standards.   Research  Triangle  Park, NC
27711.

U.S. EPA.   July  1986.   Guidelines on Air  Quality  Models (Revised!.   EPA-
405/2-78-027R.   NTIS  PB 86-245248.   Office  of  Air  Quality  Planning and
Standards.  Research Triangle Park, NC  27711.

U.S. EPA.   September 1983.   Characterization  of  Hazardous Waste Sites - A
Methods Manual:  Volume II. Available Sampling Methods.  EPA-600/4-83-040.
NTIS PB 84-126929.  Office of Solid Waste.  Washington, DC 20460.

U.S. EPA.   September 1983.   Characterization  of  Hazardous Waste Sites - A
Methods  Manual;    Volume  III.   Available  Laboratory  Analytical  Methods.
EPA-600/4-83-040.  NTIS PB 84-126929.  Office of Solid Waste.  Washington,
DC 20460.

U.S. EPA.   1986.   Test Methods  for Evaluating Solid Waste. Third Edition.
EPA SW-846.  GPO No. 955-001-00000-1.  Office of Solid Waste.  Washington,
DC 20460.

ASTM.  1982.   Toxic Materials   1n  the  Atmosphere.    STP  786.   American
Society for Testing and Materials.  Philadelphia, PA.

ASTM.   1980.   Sampling and Analysis of  Toxic Oroanics in the Atmosphere.
STP 721.  American Society for Testing and Materials.  Philadelphia, PA.

ASTM.    1974.    Instrumentation  for  Monitoring  Air  Quality.    STP  555.
American Society for Testing and Materials.  Philadelphia, PA.
                                    4-2

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APHA.   1977.   Methods  of Air  Sampling and  Analysis.    American Public
Health Association.  Cincinnati, OH.

ACGIH.   1983.   A1r  Sampling  Instruments  for Evaluation  of Atmospheric
Contaminants.  American  Conference of Governmental Industrial Hyglenists.
Washington, DC.

U.S.  EPA.   1984.  Guide to the Preparation  of  Quality Assurance Project
Plans.   Office  of  Toxic  Substances.    Office of  Pesticides  and  Toxic
Substances.  Washington, DC.
                                    4-3

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         APPENDIX A
        BIBLIOGRAPHY
             OF
       AIR MONITORING
STANDARD OPERATING PROCEDURES
             A-l

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                                APPENDIX A

                               BIBLIOGRAPHY
     APCA.  May  1987.    Proceedings  of  the  1987  EPA/APCA  Symposium on
Measurement  of Toxic  and  Related A1r  Pollutants.    VIP-8.  A1r  Pollution
Control Association.  Pittsburgh, PA  15230.

     These proceedings cover a wide  range of  topics on recent  advances In
     measurement   and   monitoring   procedures   for   toxic   and   related
     pollutants found in ambient and source atmospheres.

     APHA.   1977.   Methods  of  Air Sampling and Analysis.  American Public
Health Association.  Cincinnati, OH.

     This manual  1s a  comprehensive compilation of  standardized  methods
     for sampling and analysis of ambient and workplace air adopted by the
     APHA Intersociety Committee on Methods of Air Sampling and Analysis.

     ASTM.    1980.    Sampling  and  Analysis  of  Toxic  Organ1cs  In the
Atmosphere.    American  Society  for Testing  and  Materials.    STP  721.
Philadelphia, PA.

     This publication resulted from  the fourth biennial Boulder Conference
     on  environmental  monitoring of air quality  sponsored  by the  ASTM.
     The  conference was structured  to highlight  several major  areas of
     concern  to  environmental   scientists,  namely,   sampling for  toxic
                                    A-2

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     organlcs  1n  ambient,  workplace,  and  source-related  atmospheres;
     analyzing for important classes of pollutants such as polychlorinated
     biphenyls  (PCBs),  polynuclear  aromatic  hydrocarbons  (PAHs),  and
     polycycllc  organic  matter  (POM);  and  measuring  exposure to  toxic
     organlcs 1n the workplace.

     CARB.    February  1985.     Toxic  Ambient  A1r  Monitoring  Operation
Procedure. California  Network.   Aerometrlc  Data Division.  California Air
Resources Board.  Sacramento, CA 95814.

     CARB.   December  1986.  Testing  Guidelines  for Active  Solid  Waste
Disposal  Sites.    Stationary  Source Division.    Toxic  Pollutants  Branch.
California A1r Resources Board.   Sacramento, CA 95814.

     These  guidelines  present  standard  operating  procedures  for  the
     sampling  and  analysis  of ambient air  collected  1n  Tedlar  bags.
     Analytical procedures  are  primarily for  halogenated  volatile organlcs
     and benzene.

     Drager.   May  1985.   Detector Tube Handbook.   Dragerwerk AG  Lubeck.
Federal Republic  of Germany.

     This  handbook  presents   procedures   for   the   use   of  colorlmetrlc
     detector  tubes for a  wide range  of organic and  Inorganic compounds.
     Data  1s  provided on  standard  ranges of  measurement, precision  and
     accuracy, measurement principles, and cross-sens1t1v1ty.

     NIOSH.   February 1984.  NIOSH Manual of Analytical  Methods.   NTIS  PB
85-179018.     National  Institute  of   Occupational   Safety  and   Health.
Cincinnati,  OH.

     The NIOSH  manuals  contain a  wealth of  Information on  sampling  and
     analytical procedures for  a wide range of toxic organic and Inorganic
     species.    Although  primarily directed  at  determination of  worker
     exposure  levels, these  methods can quite often  be  applied (with
                                     A-3

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     minimal modifications)  to the  measurement of  ambient concentration
     levels of concern 1n perimeter and offsite monitoring.

     N.J. DEP.   October  1987.  Ambient A1r  Monitoring at Hazardous Waste
and  Superfund  Sites.   Division  of  Environmental  Quality.   A1r Quality
Management  and  Surveillance.    New  Jersey  Department  of Environmental
Protection.  Trenton, NJ 08625.

     This  document contains  a master  table  of  sampling  and  analytical
     methods  for ambient  air monitoring  listed  by  compound  name.    Key
     Information on  species Includes recommended  sampling and  analytical
     methods,  the  applicability  of  each method,  performance  data,   and
     reference Information.

     SCAQMD.  October 1985.  Guidelines for  Implementation  of  Rule  1150.1.
South  Coast A1r Quality  Management  District.  Engineering Division.    El
Monte, CA 91731.

     This   document   contains  standard   operating  procedures  for   the
     collection  of ambient  air  samples   at  landfill  perimeters and  for
     Instantaneous  landfill  surface monitoring,   as well  as  analytical
     procedures  for a wide range of toxic  volatile  organic  compounds.

     U.S.  EPA.   April 1984.   Compendium  of Methods  for  the  Determination
of  Toxic Organic Compounds 1n Ambient  Air.   EPA-600/4-84-041.   Office of
Research and Development.  Research Triangle  Park,  NC 27711.

     Specific  Standard  Operating  Procedures  (SOPs)  contained  1n  this
     compendium  are as follows:

     Method TO-1   Method  for   the   Determination  of  Volatile  Organic
                    Compounds  in Ambient  A1r  Using  Tenax Adsorption  and
                    Gas     Chromatography/Mass    Spectrometry    (GC/MS)*
                     (Applicable to volatile,  non-polar organic compounds.)
                                    A-4

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Method TO-2
Method TO-3
Method TO-4
Method TO-5
Method  TO-6
 Method  TO-7
 Method TO-8
 Method TO-9
Method  for  the  Determination  of   Volatile   Organic
Compounds In Ambient Air by Molecular Sieve  Adsorption
and GC/MS.   (Applicable to  highly volatile,  nonpolar
organic compounds.)

Method  for  the  Determination  of   Volatile   Organic
Compounds    in    Ambient     A1r    Using   Cryogenic
Preconcentratlon  Techniques  and  Gas  Chromatography
with  Flame  lonization  and  Electron Capture  Detection.
(Applicable to volatile, nonpolar organic compounds.)

Method   for   the  Determination   of   Organochlorine
Pesticides  and  Polychlorlnated  Biphenyls   1n  Ambient
A1r.

Method  for  the Determination of Aldehydes  and Ketones
1n   Ambient   A1r  Using   High   Performance   Liquid
Chromatography.

Method  for the  Determination of  Phosgene  1n Ambient
A1r Using High Performance Liquid  Chromatography.

Method  for  the Determination of N-N1trosod1methyl amine
1n Ambient  A1r Using Gas Chromatography.

Method    for    the   Determination   of   Phenol   and
Methylphenols   (Cresols)  1n  Ambient A1r   Using  High
Performance Liquid  Chromatography.

Method   for   the  Determination   of  Polychlorlnated
D1benzo-p-diox1ns  (PCDOs)  in Ambient A1r  Using High-
Resolution   Gas   Chromatography/High-Resolution  Mass
Spectrometry  (HRGC/HRMS).
                                A-5

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     Method TO-12   (Draft)  Method  for  the  Determination  of  Non-Methane
                    Organic   Compounds   (NMOC)   1n   Ambient  Air  Using
                    Cryogenic  Preconcentratlon and Direct Flame lonization
                    Detection  (PDFID).

     Method TO-14   Determination of Volatile  Organic  Compounds  (VOCs) In
                    Ambient  Air  Using  SUMMA  Passlvated  Canister  Sampling
                    and Gas  Chromatographlc Analysis.

     U.S. EPA.  September 1983.  Characterization of Hazardous Waste Sites
- A Methods Manual;  Volume II. Available Sampling Methods.  EPA-600/4-83-
040.  NTIS PB 84-126929.  Office of Solid Waste.  Washington, DC  20460.

     This volume  1s  a  compilation  of sampling methods suitable to address
     most   needs   that  arise   during   routine  waste   site   and  spill
     Investigations.   Twelve  methods are presented for  ambient  air,  soil
     gases and vapors, and headspace gases.

     U.S. EPA.  September 1983.  Characterization of Hazardous Waste Sites
- A Methods Manual:   Volume III. Available Laboratory Analytical  Methods.
EPA-600/4-83-040.  NTIS PB 84-126929.  Office  of  Solid Waste.  Washington,
DC 20460.

     This  volume  provides  bench-level  guidance for  the  preparation of
     hazardous  waste,  water,  soil/sediment,  biological  tissue,  and  air
     samples,  and  methods  that  can  be  used to  analyze  the   resultant
     digests/extracts  of  244  of the substances  listed  1n the RCRA  permit
     regulations.

     U.S. EPA.  February  1986.   Measurement of Gaseous Emission Rates  from
Land  Surfaces Using  an Emission  Isolation  Flux Chamber:   User's  Guide.
EPA-600/8-86-008.    Environmental  Monitoring  Systems  Laboratory.     Las
Vegas, NV   89114.
                                    A-6

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     U.S.  EPA.    December  1987.   Development  of Collection  Methods for
Semivolatile  Organic   Compounds   1n  Ambient   A1r.      EPA-600/4-87-042.
Environmental Monitoring .Systems  Laboratory.    Research  Triangle Park, NC
27711.

     U.S.  EPA.     July  1983.     Standard   Operating   Procedures for the
Preparation of Standard Organic Gas  Mixtures  1n a Static Dilution Bottle.
RTP-SOP-EMD-012.   Environmental  Monitoring Systems  Laboratory.   Research
Triangle Park, NC  27711.

     U.S.  EPA.    November  1981.   Standard  Operating Procedures  for the
Preparation  of  Tenax  Cartridges  Containing Known  Quantities  of Orqanlcs
Using  Flash  Vaporization.    RTP-SOP-EMD-011.    Environmental  Monitoring
Systems  Laboratory.  Research Triangle Park, NC  27711.

     U.S.  EPA.    November  1981.   Standard  Operating Procedures  for the
Preparation  of  Clean  Tenax  Cartridges.    RTP-SOP-EMD-013.    Environmental
Monitoring Systems Laboratory.  Research Triangle Park,  NC   27711.

     U.S.  EPA.   January 1984.   Standard Operating  Procedures  for  Sampling
Gaseous  Organic  Air  Pollutants   for  Quantitative  Analysis  Using  Solid
Adsorbents.      RTP-SOP-EMD-018.      Environmental   Monitoring   Systems
Laboratory.   Research  Triangle Park, NC  27711.

     U.S.  EPA.   July 1985.   Draft Standard Operating  Procedures  No.  FA112A
-  Monitoring for  Gaseous  Air Pollutants  Using the  Gilian LFS Model  113
Dual  Mode Air  Sampling Pumps.    Environmental  Monitoring  and  Compliance
Branch,  Environmental  Services   Division,  Region  VII.    Kansas City,  KS
66115.

      U.S.  EPA.    June  1984.   Standard Operating Procedures for the GC/MS
Determination of Volatile  Organic Compounds Collected on Tenax.  RTP-SOP-
EMD-021.  Environmental Monitoring Systems Laboratory.   Research Triangle
Park,  NC  27711.
                                     A-7

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     U.S. EPA.   August  1983.   Development  of Protocols  for  Ambient Air
Sampling and  Monitoring at Hazardous  Waste Facilities:   Methods Summary
Report.  Office  of Solid Waste.   Land Disposal Branch.   Washington, DC,
20460.

     U.S.  EPA.     1984.    Field  Standard  Operating  Procedures  for  Air
Surveillance.    FSOP  #8.   Office of  Emergency  and  Remedial  Response.
Washington, DC 20460.

     U.S.  EPA.    1983.    A1r  Pollution  Training  Institute  Course  435;
Atmospheric Sampling.   EPA-450/2-80-004.   Environmental  Research Center.
Research Triangle Park. NC  27711.

     U.S.  EPA.    November  1980.    Ambient  Monitoring  Guidelines  for
Prevention of Significant Deterioration fPSDK  EPA-450/4-80/012.  NTIS PB
81-153231.    Office  of  A1r Quality   Planning and  Standards.   Research
Triangle Park, NC  27711.

     U.S. EPA.  June 1983.  Technical Assistance Document  for  Sampling and
Analysis of  Toxic Organic  Compounds  1n  Ambient A1r.   EPA-600/4-83-027.
NTIS PB 83-239020.  Office of Research and  Development.  Research Triangle
Park, NC  27711.

     U.S.  EPA.     1977.    Quality Assurance  Handbook  for  A1r  Pollution
Measurement Systems:  Volume II. Ambient Air Specific  Methods.  EPA-600/4-
27-027a.  Environmental  Monitoring Systems Laboratory.  Research Triangle
Park, NC  27711.

     U.S. GSA.   1987.   Code of  Federal  Regulations.  Title  40.  Part 50.
Appendices A-G  and J.   Office of  the Federal  Register.   Washington, DC
20402.

     The listed  appendices to  40  CFR  50 contain EPA Reference Methods for
     the sampling  and  analysis of SOz, TSP, CO, 03, NOs.  Pb,  and PM-10 1n
     ambient  air.
                                    A-8

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         APPENDIX B
           EXCERPT
             FROM
TECHNICAL ASSISTANCE DOCUMENT
             FOR
    SAMPLING AND ANALYSIS
             OF
   TOXIC ORGANIC COMPOUNDS
        IN  AMBIENT AIR
    (U.S. EPA. JUNE 1983)
              B-l

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