United States
Environmental Protect tern
Aflency
Air Pollution Training Initltute
MO 17
Cnvlronwnt*! Rtittrch Center
Research Trl«nole Park. »C 27711
" EPA 450/2-91-003 <
 October 1990
     APTI
     Correspondence Course 404
     Assessing
     Multiple Pollutant
     Multiple Source
     Cancer Risks from
     Urban Air Toxics
    Guidebook

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                                EPA-XXXIX-XX-XXX
                                October 1990
APTI
Correspondence Course 404
Assessing
Multiple Pollutant
Multiple Source
Cancer Risks from
Urban Air Toxics
Guidebook
Prepared bys

Pacific Environmental Services
3708 May fair Street, Suite 202
Durham, North Carolina 27707
Under Contract No.
68-02-4393
EPA Project Officer
Charles Pratt

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                                 Notice

This is not an official policy and standards document. The opinions and selections
are those of the authors and not necessarily those of the Environmental Protection
Agency. Every attempt has been made to represent the present state of the art as
well as subject areas still under evaluation. Any mention of products or organiza-
tions does not constitute endorsement by the United States Environmental Protec-
tion Agency.

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                              Table  of Contents
                                                                          Page
Course Introduction  .,	„.,	„__„.„„..,...„..,._„.».	,„.„„„„	„.„„.._.   0-1

Section 1.  Ambient Air Quality Monitoring .____„__	„...„_,	,_«__.™™»^.   1-1
       Review Exercise r™™_™™».™.™™»™.™....	..____.„„	„	„.   1-3
       Review Etectse Answers	™,^^___™_______M™w_^__^ra™_™_   1-g

Section 2.  Emission Inventories _™™_™_™^.«™»™TOM™™«™™.,	»™.™™««...™..,_   2-1
    .   Review Exertae ™_™_____~_^™™_^_™™_«™^^™^™™™^^^^^^.»_w™,  2-3
       Review Exercise Answers  ™__,_,™«,...	«.»™™™™™™^.	i™»™™.._	   2-7

S^tion 3.  Dispersion Modeling —...		™™_«_«™_m_™™™^___.^^»__»_™   3-1
       Review Exercise ____	^._™	,	«___™..	™.	.	^   3-3
       Review Biercise Answers  »_	.	™___™.™™™_™__™™™_»__™™™™™™..   3-6

Section 4.  Expoaae and Risk Assessment 	»___	^.«	»>___^_	,	„„,	^   4-1
       Review Ei^me —»«»»«—»»_-.	_^™^™^™_~^—«™^™™,^^__»_«_^..   4-2
       Review E*ercfee Answers  „,	,m,m^m.,	™,™™,«™™_™™..».,™M^».»_,.,»™,..™™...   4-6

Section 5.  Control Strategy Simulation and Evaluation ™^.,——„„...„„.....„.,—^.	.   5-1
       Review Eiercise .	™	.	,	,™.»^,_.»	,™	„„.,	:	..   5-3
       Review Ejarcise Answers	„	—,»^,»_^.	^...^.^m.,.^..	.^	,	5-5

Section 6.  Computerized Data Handling  ,™.™™.™,™.,,.,,™...,.™«™.»..,..........^	».™,,.™™,..   6-1
       Review Exercise ,«^™_M»	»™™™.,.™™,..««™.,™™~,«w,,,,..,,.,.......™™,.™..	....   6-3
       Review Exercise Answers  ...,™....	.,„	^..«.™™....__™.™......	..„   6-7
                                        111

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                       Course Introduction
                               Overview of Course
 Course Description
This training course is a 24-hour correspondence course dealing with methods that have been used
in assessing multiple source, multiple pollutant risks from air toxics exposures In urban areas. The
course presents synopses of assessment procedures that have been used to quantify urban air toxics
exposure and risks, and offers insights into the suitability of these procedures in particular
applications.  Course topics include:

   *  use of ambient air monitoring data, emission inventories, and dispersion modeling in urban  '
     assessments
   *  the purposes to which exposure and risk assessments have been  put
   *  the use of simulation in evaluating potential risk reduction of specific control strategies for
     urban air toxics exposures
   *  data handling options and selection
Course Goal

The goal of this course is to familiarize you with general assessment tools for exposure and risk
from urban air toxics and with specific considerations for selecting the appropriate methods for
conducting such assessments.
Course Objectives

Upon completion of this course, you should be able to:

  •  understand the purposes for which urban air toxics assessments have been undertaken;
  •  identify techniques that have been used by others;
  -  describe the strengths and weaknesses of various methods for estimating exposures (ambient
     air quality monitoring versus emission inventories/dispersion modeling);
  •  select appropriate tools, including data handling systems, for specific urban air toxics
     assessments; and
  •  understand the appropriate interpretations and applications of the results of exposure and
     risk assessments and control strategy simulations.
                                          0-1

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Lesson Titles, Sequence, and Trainee Involvement Time
Lesson Number              Lesson Title       .          Trainee Involvement
                                                         time (hours)

     1               Ambient Air Quality Monitoring         4

     2               Emission Inventories                    4

     3               Dispersion Modeling                    5

     4               Exposure and Risk Assessment          5

     5               Control Strategy Simulation and
                      Evaluation                            3

     6               Computerized Data Handling            3



Requirements for Successful Completion of this Course

In order to receive 2.5 Continuing Education Units (CEUs) and a certificate of course completion,
you must:

  *  take two quizzes and a final examination.
  •  achieve a course grade of at least 70% (out of 100%) determined as follows;
       - 20% from Quiz 1
       - 20% from Quiz 2
       - 60% from the final examination
                                       0-2

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                            Use of Course Materials
Necessary Materials
   •  "APT1 Correspondence Course 404"
   •  EPA 450/2-89-010," Assessing Multiple Pollutant Multiple Source Cancer Risks from Urban
      Air Toxics:  Summary of Approaches and Insights from Completed and Ongoing Urban Air
      Toxics Assessments Studies."
   •  pencil or pen
   *  calculator
   *  quizzes and exams

 Use of this Guidebook

               Relationship Between Guidebook and Assigned Reading Materials

 This guidebook directs your progress through the reference text "Assessing Multiple Pollutant
 Multiple Source Cancer Risks from Urban Air Toxics.*

                             Description of Guidebook Sections

 This guidebook contains six reading assignment sections that correspond to the six lessons of the
 course. Each section contains the following:

   * reading assignment
   * reading assignment topics
   * section's learning goal and objectives
   • reading guidance
   * review exercise
Instructions for Completing the Quizzes and the Final Examination

  •  You should have received, along with this guidebook, two quizzes and a final examination,
  *  Quiz No. 1 covers the first three sections of the guidebook. Take this quiz after you have
     completed these three sections and the review questions for each section.
  •  Quiz No. 2 covers the last three sections of the guidebook.  Take this quiz after you .have
     completed the last three sections and the review questions for each section.
  «  After completing each quiz and the final exam, mail the quiz/exam answer sheet to the
     following address:

               Air Pollution Training Institute
               Environmental Research Center
               MD-17
               Research Triangle Park, NC 27711

  •  After completing a quiz, continue with the course.  Do not wait for quiz results.
  •  Quiz/exam and course grade results will be mailed to you.
                                          0-3

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If you hove questions, contact:
          Air Pollution Training Institute
          Environmental Research Center
          MD-I7
          Research Trisftigle Park, NC  27711

          Telephone Numbers:
              Commercial: (919)541-2401
              FTS: 629-2401
                                       0-4

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                            Section   1
         Ambient  Air  Quality  Monitoring
Reading Assignment

Pages 23-72 of EPA-450/2-89-010, "Assessing Multiple Pollutant Multiple Source Cancer Risks
from Urban Air Toxics."
Reading Assignment Topics

     Use of ambient air monitoring data in urban assessments
     Pollutant coverage
     Site selection
     Sampling periods, frequencies, and duration
     Evolving monitoring techniques
     Insights into the use of monitoring in air toxics programs
Learning Goal and Objectives

                                  Learning Goal

To familiarize the reader with decisions involved in developing and implementing an ambient air
quality monitoring plan, and, through the examination of example plans, to illustrate the types of
trade-offs and compromises involved in these decisions.

                                Learning Objectives

When you have completed this section, you should be able to:

  •  understand the usage of ambient  air monitoring data in an urban air toxics program
  *  evaluate the tradeoffs and compromises inherent in design of an effective monitoring plan
  •  describe the technical issues involved in sample accuracy, site selection, and sample analysis
  •  understand the objectives for the air toxics monitoring programs
  •  define terms such as pollutant coverage, spatial coverage, temporal coverage, and sampling
     period, frequency and duration
  •  be familiar with some basic sampling and analysis methods
  «  describe some evolving monitoring technologies
  •  describe ways to cut costs in monitoring programs
                                       1-1

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Reading Guidance

   *  When you have finished the reading assignment, complete the review exercise for Section 1.
     It begins on the following page.
   «  After you have answered the review exercise questions, check your answers The correct
     answers are listed on the page immediately following the review exercise.
   *  For any review exereise questions that you answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page.
   *  After you have reviewed your incorrect answers (if any), proceed to Section 2 of this
     guidebook.
                                           1-2

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                            Review  Exercise
Now that you've completed the assignment for Section 1, please answer the following questions.
These will help you determine whether or not you are mastering the material.
                       *

 1.   Identify as many of the following that are evaluated better by air monitoring than by air
     pollution dispersion models:

     a.   transformation products
     b.   pollutants emitted directly
     c.   gradual buildup of background level pollutants
     d.   pollutant transport from other areas

 2.   Ambient air monitoring data provide all tlte following for multi-source, multi-pollutant
     urban assessment except:

     a.  assessment of dispersion model performance
     b.  characterization of toxic pollutant exposures and risks
     c.  high accuracy measurement and analysis for many substances found at low concentration
     d.  evaluation of emission inventory accuracy

 3.   Ambient air  monitoring data can be used in     '_	.
     a.  verifying specific operating permit conditions
     b.  mutagenic bioassays
     c.  source apportionments
     d.  none of the above
     e.  all of the above

4.   The cost of monitoring programs for toxic air pollutants can be reduced by:

     a.  sampling over shorter time periods
     b.  sampling over longer time periods

5.   Order the following §7 through d to describe the process by which excess cancer cases are
     estimated:

     	multiply exposure levels by cancer unit risk factor
     	estimate population exposure
     	superimpose  cancer risk over population distribution
     	measure ambient  air toxics levels

6.   True or False?  The greater the number of samples analyzed, the more variations in the
     concentration of pollutant in time and  space can be described.

7.   Site selection for sampling is influenced by:

     a.  gradient of concentrations
     b.  laboratory detection limit of pollutants
     c  air quality statistics of concern
     d,  a and b above
     e.  a, b, and c above


                                          1-3

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 8.   Sampling locations with	gradients require the most careful site location:

      a.  flat
      b.  gradual
      c.  steep

 9.   Which two of the following pollutant groups have been emphasized in monitoring programs
      to date:

      a.  aldehydes
      b.  volatile organics
      c,  semi volatile organics
      d.  metals
      e.  ketones

 10.   Which of the following pollutants were covered in all of the nine programs described in this
      chapter:

      a.  asbestos                      e.  chloroform
      b.  carbon tetrachloride           f. xylene
      c,  benzene                      g,  perehloroethylene
      d.  toluene

 11.   Match the type of site selection below to a program purpose:

                   SITE SELECTION                 "           PROGRAM PURPOSE

      a.   Site only where concentration gradients of    	  Characterize regional pollutants and
          targeted pollutants are steepest.                   variation.

     b.   Many sites, few specific substances           	  Verify emission inventory and assess
          measured.                                       maximum individual risk.

     c.   Few sites, in-depth and broad spectrum       	  Compare with specific model outputs.
          analysis.

12,  Which one of the following is not true of a good sampling station?

     a.  sampling line intake should be from 2 to 10 m above the ground
     b.  sampling probe should extend at least 2 m from supporting structure
     c.  distance between obstruction and the sampler should be at least the height of the
         obstruction
     d.  sampling probe must be mounted on the windward side if located on a  building

13.  Based on the studies reviewed, rooftop sampling	(was/was not) demonstrated to
     interfere with the collection of representative data.

14.  Assign each design  factor to its correct definition:

     a. sampling period             	  number of hours that compose each sample

     b. sampling duration           	  length of time field  program is operational

     c. sample frequency            	  separation of sample days (every 2nd, every 5th, etc.)
                                            1-4

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 15.   A minimum sampling period of one season may be reasonable for which of the following
      objectives?

      a.  to assess model performance
      b.  to estimate annual average concentration

 16.   To show diurnal differences while retaining the ability to compute daily averages, one would
      choose the following type of sampling duration:

      a.  24-hour samples
      b.  12-hour daytime samples
      c  12-hour daytime and nighttime sets

 17.   Place a T for Tenax*" or a C for "canister" in each of the sets of statements below
      describing sampling techniques for volatile organics.

      	absorbent material
      	collects ambient air samples
      	lower detection limits
      	higher detection limits
      	documented unreliability
      	greater day-to-day consistency in results

 18.   "Distributed volume sampling protocol" for use of Tenax* is:

      a.  combining gas chromatography and mass spectrometry analysis methods
      b.  varying sampling volume by probe location
      c.  use of 4 sampling tubes at different flow rates

 19.   Semivolatile organic pollutants can be sampled by collection on	.

      a.  Tenax* or canister
      b.  polyurethane foam or XAD-2
      c.  gas  chromatograph or mass spectrometer

20.  True or False?  Metals can be collected using either high volume samplers or fine paniculate
     samplers.

21.  Formaldehyde, aldehydes, and ketones were sampled by which of the following methods in-
     some of these studies:

     a. polyurethane foam
     b. 2-4,dinitrophenylhydrazine cartridges
     c. high volume samplers
     d. a and b
                                           1-5

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 23.  Match the pollutant to an appropriate sampling method, and to an appropriate analyzation
      method.

          Pollutants

      a.  volatile organics
      b.  semivolatile organics
      c.  metals
      d.  aldehydes and ketones

               Sampling                Analvzation

      	  high volume samplers        	  G0MS
      	  Tenax*                      	  HPLC
      	  2-4,diaitrophenyl-            	  GOMS with HPLC
           hydrazine  cartridges          	  X-ray fluorescence spectroscopy
      	  poryurethane foam

 23.  The Total Exposure Assessment Methodology (TEAM) studies collect	data on 20
      air pollutants.

      a. personal and stack
      b. stack and ambient
      c. ambient and personal
      d. personal,  ambient, and stack

 24.  Match the following acronym to its definition, pint:  All concern evolving monitoring
      techniques.]

      	   IACP                    a.    Portable infrared sensor housed in van.
      	   TAGA*
      	   ROSE*                   b.    Mobile mass spectrometry/mass spectrometry system used to
                                         collect near real-time air quality concentrations.

                                    c.    Broad program designed  to identify species most likely to be
                                         carcinogenic and their sources.

 25.   True  or Fate? Both the TAGA* and the ROSE* systems suffer from having high pollutant
      detection limits.

 26.   True or False? Sample compositing has been used successfully  for many years for ambient
      air sampling.

 27.   Sample compositing involves   ?

      a.   combining short-term samples (e.g., < 24 hours) after collection
      b.   collecting long-term, intermittent samples
      c   neither a nor b
      d.   both a and b

28.  True or False? In selective analysis, easily measured pollutants  that relate to pollutants
     more difficult to  measure are selected for analysis.

29.  True or False? Measured air quality data are inherently better than modeled concentrations.
                                            1-6

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30.  Circle any of the following which are true limitations of measured air quality data.

     a.  low number of sites and samples
     b.  sampling and analytical uncertainties
     c.  inability to characterize concentrations at key receptors
     d.  high cost to obtain representative data
                        *
31.  Ideally, for studies that emphasize cancer risks, pollutant concentrations should be estimated
     over a period of       .

     a.  24 hours
     b.  one season
     c,  one year

32.  True or False? Among the studies described in this chapter, the sampling networks had a
     size range of from 1 to 13 sites in an urban area.

33.  Which of the following will cause temporal patterns of pollutant concentration to vary if the
     receptors are dominated by area-sources:

     a.  seasonal variability
     b.  industrial clusters
     c.  diurnal patterns
     d.  a and c
     e.  a through c above

34.  Acute npncancer risks pose substantial challenges in terms of temporal coverage because of
     their relation to	.

     a.  short-term exposures
     b.  long-term exposures
     c.  both a and b
                                             1-7

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                     Review  Exercise Answers
                                                                          Page(s) of
                                                                          Urban Air
                                                                          Toxics Manual

  1.   a, c, d „„	.	_	_________	________	,	_________    24
  2.   c .	__	.,	_______________	„„..	__	.	_	„    23-25
  3,   e	____	™_	_	;	,„,„	,	„	__	__________    24-25
  4.   b	..	.	...»	.	...........	______	....	..	    25
  5.   c, b, d, a .„..„.	___	.	.	„	.	_    23-24
  6.   True	..	.	.	„	.	..	„	.....	    25-27
  7.   e		    26-27
  8.   c		.	__    26
  9,   b, d „	.	.	„	.	...	.	.	    33
 10.   b, c, e, g			___	.	.	    34-37
 11.   c, a, b ..	„„.	»	_	..„.	„	_	_	.	„__„„_    39-47
 12.   c ...	_	_	.	..	_	;	_____	,™._«™____™™~    47
 13.   was not	...	...	_____	_________	_________________	__	    47-48
 14.   b, a, c „„„.	,„	.»..._..__.....™_™_m__™..____™™™    48
 15.   a _™™_.	,—	™™,__™™	.___™«	.    48-51
 16.   c	,.	.	»..„	_™	__™™_«™m_™™__	    52
 17.   T, C, T, C, T, C ««.	™™.™.™...™	„,.	»™.	....................	..................    54
 18.   c	™J	1..	.	_...™.™.	».._™™^	....	.	__™.__.    54
 19.   b	.	„	    58
 20.   True	.	._	    58
 21.   b	„		    59
 22.   c, a, d, b and a, d, b, c	.					...    54-59
 23.   d	.......	.	.	.„.	„	„	.	    59
 24.  c, b, a	....	..	.	„„.	„,.„	.	.	    61-62
 25.  True	„	.	.....	.	.	    62
 26.  False „..,.„.„...„»...„„„	.	„...„.._„	_„	„	,„	»	...„__..    63
 27.  d .„..,„,	„„».....„....„,.„..	_.„_„	__.	„	.	...    63
 28.  False™		__.			.....	.	,	.	.	    64-65
 29,  False ____._..„	.........	___._.„_	......	.-__—.	».    66
 30.  a, b, and d _		.	.	„...„„.	.	.	    66-67
31.  c		...........	.			._.	._-    68
32.  True		_		.	.	.	..	...	...	    69
33.  d	     70
34.  a	_	    71

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                            Section   2
                     Emission Inventories
Reading Assignment

Pages 73-94 of HPA-4SQ/2-89-01Q, "Assessing Multiple Pollutant Multiple Source Cancer Risks
from Urban Air Toxics.*
Reading Assignment Topics

     Use of emission inventories in multi-pollutant, multi-source urban air toxics assessments
     Pollutant coverage
     Source coverage
     Estimating emissions
     Spatial and temporal resolution
     Quality assurance
     Insights into compiling inventories for urban air toxics assessments
Learning Goal and Objectives

                                   Learning Goal

To teach the reader the uses of emission inventories in urban air toxics assessments, define and
describe the components of inventories, and consider some insights into building inventories.

                                 Learning Objectives

When you have completed this section, you should be able to:

  *   understand the usage of emission inventories in multi-pollutant, multi-source urban air toxics
     assessments;
  *   identify pollutants and sources covered by urban air unties assessments;
  *   identify several approaches for estimating emissions of air toxics;
  *   understand basic aspects associated wiih incorporating point and area sources into an
     emissions inventory, and
  *   identify methods for assessing the quality of an emissions inventory.
                                       2-1

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Reading Guidance

  •  When you have finished the reading assignment, complete the review exercise for Section 2.
     It begins on the following page.
  *  After you have answered the review exercise questions, died your answers The correct
     answers are listed on the page immediately following the review exercise,
  *  For any review exercise questions that yon answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page,
  *  After you have reviewed your incorrect answers (if any), proceed to Section 3 of this
     guidebook.
                                           2-2

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                           Review  Exercise
Now that you've completed the assignment for Section 2, please answer the following questions.
These will help you determine whether or not you are mastering the material.
 1.   Emission inventory data are used as input to air dispersion models for estimating	
     across an urban area.

     a,  concentrations
     b.  exposures
     c.  risks
     d.  all of the above
     e.  a and b only

 2.   The chapter lists the following 20 compounds that account for the vast majority of aggregate
     cancer incidence in most of the studies reviewed.  Of these, which five contributed most to
     aggregate incidence? 	

     a. Arsenic                h.  Chloroform                 n.  Formaldehyde
     b. Benzene               I.  Chromium (total or +6)    .  o.  Methylene chloride
     c. BaP                   j.  Ethylene dibromide          p.  Perchloroethylene
     d. Beryllium              k.  Ethylene dichloride          q.  POM
     e. 1,3-butadiene           L  Gasoline vapors             r.  Trichloroethylene
     f. Cadmium              m.  Ethylene oxide              s.  Vinyl chloride
     g. Carbon tetrachloride

 3.   POM is the acronym for	.
4.   The problematic form of chromium from a cancer risk stand point is
5.   True or false? POM is sometimes called products of incomplete combustion.

6.   One approach to inventory emissions of POM was to use emissions of the surrogate
     compound	as representative.

7.   When using the "comparative potency factor approach" method to estimate risk from POM,
     	can be inventoried as representative of POM emissions.

     a.  total paniculate emissions
     b.  the solvent extractable fraction of total paniculate
     c  both a and b
     d.  neither a nor b

8.   True or False? There is a general consensus among study managers that the comparative
     potency factor approach, rather than the BaP surrogate approach, is most suitable for
     estimating cancer risk from POM.
                                          2-3

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  9.   To model both ambient Or** and total chromium levels, one mast:

       a.  measure the ambient level of each
       b.  assume all chromium is Cr**
       c,  distinguish between Cr** and total chromium directly in the inventory
       d.  a or c
                         *
  10.   True or false?  Cr** can not be directly measured at typical ambient levels.

  11.   Which of the following forms of beryllium is not considered to be the one of the more
       carcinogenic forms.

       a.  ore
       b.  oxide
       c.  fluoride
       d.  phosphate
       e.  sulfate

  12.   True or false? The various studies done so far seem to show that risks are reasonably
       estimated if one assumes that all beryllium and nickel emissions are as carcinogenic as the
       most potent compounds containing these elements.

 13.  The studies discussed in this section used	to estimate exposure to secondarily
       formed formaldehyde.

      a. emission inventories of precursors
      b. ambient air monitoring data

 14.  True or false? No validated models exist yet for predicting transformation products from
      precursor inventory data.

 15.  Which of the following types of sources are included in any comprehensive emission
      inventory?

      a,  industrial point
      b.  TSDFs
      c.  area
      d.  mobile
      e.  a,c,d
      f.  a through d above

16.   Which of the following was not used in the studies reviewed to estimate toxic emissions from
      existing data bases?

      a.  conduct source  specific surveys for the toxic pollutants
     b.  use the species  factor method
     c.  apply an air toxics emission factor to the existing throughput or activity level

17.   True or False?  The species factor method of toxic emissions estimation involves applying
     species factors to existing toxic survey data.

18.	 is a measure of how finely emissions data are subdivided in space.

19.   True or False? A measure of how finely emissions data are subdivided in time is called
     temporal resolution.

                                            2-4

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 20.   The resolution of any risk estimates can exceed the resolution of input data	.

      a,   none
      b.   by no more than a factor of 2
      c.   by no more than a factor of 10

 21.   Typicalry, point sourte locations are known to the nearest	km for areawide cancer
      assessments.

      a.   0.01
      b.   0.1
      c   LO
      
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28.  Emission inventory review should be conducted	to help ensure the best
     possible inventory procedures and data are being used.

     a.  during the planning stages
     b,  at the end of the data collection effort
     c  when the results were compiled
     d.  all of the above,
     e.  a and b only

29.  True or False?  Defining the study area as large as possible may help to account for local
     background levels of pollutants that are not secondarily formed or due to gradual buildup.

30.  Aggregate cancer risk due to exposure to primary formaldehyde emissions is probably
     	from secondary formaldehyde.

     a.  less than
     b.  about the same as
     c.  greater than

31.  Point source characterization is likely to be	for areawide aggregate cancer
     incidence estimates than for maximum individual risks.

     a.  less complex
     b.  about the same in complexity
     c  more complex

32,  True or False? The use of several socioeconomic or land use parameters as surrogates for
     allocating area source emissions is to be preferred to the use of a single indicator, such as
     population.

33.  True or False? EPA's Human Exposure Model internally allocates emissions to the
     subcounty level.

34.  True or False? Temporal resolution of hourly variability is probably more useful for studies
     that focus on cancer than for studies that focus on noncancer effects.
                                            2-6

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              Review Exercise Answers
 2.
 3.
 4.
 5.
 6.
 7.
 8.
 9.
10,
11.
12.
13.
14.
15.
16.
17.
18.
19.
20,
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
*
d ... 	 	 	 	 	
b, e, i, n, and q 	 	 	
polycyclic organic matter ... ™ 	 ............................
Cr** or hexavalent chromium „ 	 	 .. 	 .. ..
True . „,„, ..„,.»,.»,.,....„„ . 	 ^«
benzo(a)pyrene or BaP 	 .
C ..,™».™™, . —™™™™
Fake.
c
True 	 „ ..... . . . 	 , ..
b ..... „ 	 „.. ... 	 „.. 	
False 	 .... 	 	 	 	
b 	 . 	 „ 	 „ 	
True 	 ........... 	 „..„.„,.„. 	 , 	 „...„,_,
c »*»
a i liiu^,u™™..,, 	 	 	 	 	 ,..,.„.. 	 ,.,...t..^«a vuui
False
Spatial resolution __
True ™. „.«. „
g
b
bd,e 	 . 	 .. 	 	 	 	 . 	 . 	 „„
e ...... 	 	 	 	 ...............
True ... 	 . 	 ... 	 . 	 	 	 	 	 	 ».
False „. ..,.„ .... 	 ... 	 ™ .- . _...™«..^»
2
d - «- .......
d „,,,.. — - 	 —
True
a
9
True 	 	 	
True 	
False
Pa|e(s) of
Urban Air
Tories Manual
	 .. 	 . 	 .... „ . 74
79
.... 	 .„ 	 79
.„„.„ 	 , 79
— — «. ...„. 80
80
	 ...,,,,, ft)
-— , ,,,,,-,-„- 80
81
.» «— 81
	 .„ „. 	 . 	 ._ 81
	 . 	 	 	 81
	 	 „„ 	 82
82
„ .. 82
83-84
§4
86
~™.. 86
86
87
	 	 „ 	 87-92
	 	 	 88-89
„. 	 „ 	 . 	 „ 88
.. „. 	 	 ._. 89
„..„ „„.__.„..„........„..„„ 	 89
.. ™ 90-91
.„ ... — . 90
„ 	 .. .. - . 	 91-92
,. 	 „ ... m. „„...„_. 92
_ 	 „ 	 „„.„_ .. 92
92
	 	 	 92
„ . „ „ 	 ... 	 	 	 	 93
                            2-7

-------

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                             Section  3
                      Dispersion Modeling
 Reading Assignment

 Pages 95-145 of EPA-45Q/2-89-010, "Assessing Multiple Pollutant Multiple Source Cancer Risks
 from Urban Air Tories".
Reading Assignment Topics

     Use of models for estimating exposure in multi-pollutant, multi-source urban assessments.
     Decisions affecting modeling protocols
     Model Selection
     Release specifications
     Selection of receptor network
     Meteorological data
     Decay, transformation, deposition
     Model execution
     Model performance evaluation
     Insights
Learning Goal and Objectives

                                   Learning Goal

To grasp that a model's performance for a specific use depends upon the accuracy of emissions
data, the representativeness of meteorological data, and how well the application matches the
source and terrain types for which the model was originally developed.

                                 Learning Objectives

When you have completed this section, you should be able to:

  *   understand that dispersion modeling is a powerful tool as applied to air toxics studies;
  *   recognize the limitations on modeled results as a function of available input data, as well as
     the compatibility of the model to  the particular application;
  «   identify the strengths and weaknesses of modeled results vs. those obtained by ambient
     monitoring;  and
                                       3-1

-------
     recognize that there are a wide variety of dispersion models available (some of which are not
     EPA-approved) specific to some of the following factors:  short-term vs. long-term analysis,
     complex vs. simple terrain, urban vs. rural areas, and point vs. area sources;
Reading Guidance
                       *
  •  Many of the dispersion models discussed are identified and discussed in the EPA document,
     "Guideline on Air Quality Models (Revised)" EPA-450/2-78-027R, OAQPS, Durham, NC,
     1986.
  •  UNAMAP is an acronym for User's Network for Applied Modeling of Air Pollution. This is
     a collection of FORTRAN source codes for air quality models. The most recent version of
     UNAMAP (Version 6, dated July 1986) contains 23 models and associated processors.
  *  The term formulation refers to a dispersion model run with specific input data and control
     settings. A dispersion model can be run with multiple formulations.
  *  When you have finished the reading assignment, complete the review exercise for Section 3.
     It begins on the following page.
  •  After you have answered the review exercise questions, check your answers.  The correct
     answers are listed on the page immediately following the review exercise.
  •  For any review exercise questions that you answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page.
  •  After you have reviewed your incorrect answers (if any), proceed to Section 4 of this
     guidebook.

-------
                            Review Exercise
Now that you've completed the assignment for Section 3, please answer the following questions.
These will help you determine whether or not you are mastering the material.
                        *

 1.  Dispersion modeling is a powerful tool as applied  to toxic air pollutant studies.  Modeling
     may be used to:

     a.  estimate ambient concentrations of pollutants
     b.  assist in the planning of monitoring programs
     c.  verify emission inventories when used in conjunction with monitoring data
     d.  all of the above
     e.  a and c only

 2.  True or False?  Gaussian models currently in use for toxic pollutant analysis were originally
     developed for criteria pollutants, and therefore had to be extensively revised for air toxics
     analysis.

 3.  How well a model performs for a specific use depends upon which of the following:

     a.  the accuracy of emissions data
     b.  the emission source release specifications
     c   the representativeness of meteorological data
     d.  how well the application matches the source and terrain types for which the model was
         originally developed
     e.   all of the above
     f.   only a, b, and d

For the following questions (4-7), indicate by inserting the appropriate letter whether either a
modeling analysis (A) or a monitoring analysis (B) is more appropriately described.

4.   	Generally requires a smaller amount of resources to conduct a comprehensive ambient
     air quality assessment.

5.   	Provides extensive spatial and temporal resolution of estimated concentrations.

6.   	Can isolate the effect of any single source or evaluate the impact of any aggregate of
     sources.

7.   	Cannot analyze hypothetical situations, such as the imposition of a range of control
     scenarios,

8.   True or False?  Long-term modeling is typically conducted in air toxics risk assessments due
     to the emphasis on chronic health effects.  However, short-term modeling is also employed
     to aid in model performance evaluation.

9.   True or False?  A combination of models was employed in the studies  of interest because
     none of the current models in the EPA Guideline on Air Quality Models provide adequate
     treatment of complex industrial  sources and urban-scale area sources.
                                           3-3

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 10.   True or False?  SHOUT Is a version of HEM/SHEAR as developed by the South Coast
      Study.

 In questions 11-15, match each of the following dispersion models with the characteristic most
 representative of each.

 11.   HEM/SHEAR     _;	                       a.    second level screening model for
 12.   GAMS            ii:                               estimating short-term averages in urban
 13.   ISCLT            	                            areas with complex terrain
 14.   COM             	
 15.  • SHORTZ         	                       b.    provides flexibility for evaluating
                                                       complex industrial sources

                                                  c.    exposure modeling system that
                                                       internally includes national population
                                                       data

                                                  d.    its greatest strength for modeling urban
                                                       soup is its detailed area source
                                                       treatment

                                                  e.    similar operation to HEM, although
                                                       the approaches differ for close-in
                                                       receptors

 16.  True or False? Exposure modeling without consideration of terrain rise (e.g., complex
     terrain) can lead to large model inaccuracies for source categories that release from high
     stacks. A bias to overestimate impacts for tall stacks can occur on this basis for areas with
     moderate to high terrain.

 17.  The following meteorological parameters are required for optimal use of the dispersion
     models used in these studies:

     a.   wind speed/wind direction
     b.   polar coordinates
     c   atmospheric stability
     d.   ambient temperature
     e.   all of the above
     f.   a, b, and d
     g.   a, c, and d

18.   Atmospheric stability is a term used within a dispersion model to indicate the rate of
     horizontal and vertical  pollutant mixing within a plume. 	conditions  produce
     vigorous mixing,	conditions indicate moderate mixing, and	conditions
     result in very limited mixing.

     a.   Neutral / stable / unstable
     b.   Unstable / neutral / stable
     c.   Stable / neutral / unstable

19.   True or False?  The incorporation of diurnal or seasonal differences in meteorological
     conditions can be important when modeling industrial facilities or area source categories that
     have distinct diurnal or seasonal patterns in emission rates.

-------
20.  True or False?  The models used in all of these studies contain simplified treatments for
     decay, deposition, and transformation.  These factors have been significant issues in most
     studies of urban air toxics.

21.  True or False?  Model performance evaluations are only an option for studies that have an
     adequate measured data set against which to compare the modeled values.
                        JL
22.  True or False?  It is a common misconception of reviewers of studies that have undertaken
     mode! performance testing that measured data are used to calibrate model output to reduce
     bias, thereby showing a better match with observed results.

In questions 23 through 31, a characteristic or effect of dispersion modeling is presented. For
each of these, insert the letter of the type of model input data (meteorological, source, or
receptor) which most closely matches.
23.  Direction and speed of pollutant
     transport	

24.  Emission release temperature and
     velocity	

25.  Horizontal and vertical dispersion	

26.  Grid-based vs. polar coordinates	

27.  Complex terrain considerations	

28.  Release height	

29.  Vertical  extent of turbulent mixing


30.  Location of maximum exposures :

31.  Types of pollutants	
a.    Meteorological data
b.    Source data
c.    Receptor data
                                            3-5

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                      Review  Exercise  Answers
                                                                                 of
                                                                          Urban Air
                                                                          Toxics Manual
  1.   d .„	„	.	.	„.„._„,..	     %
  2,   False	.........	....	.	.	..._...	..	.	    96
  3.   e	.	.	.............	.....	.......	     96
  4.   A	.	„	.	.	.„	,„.»	..     97
  5.   A	...	....™.	„.,.	.	._..	«._^^.     97
  6.   A..	,	.	.	,	     97
  7.   B —»»	..	-	«™™_	~-»^__	,	„	97
  8.   Tnie™..,.™™^.™™.™..™,.,.™™™™™™™™^.^.....	„	.™™__™	^™^^™_	„     1Q2
  9.   True _~~_~~	...™™.™__™™™.»~_~~~_.™«»^~_.»__.™^^™™MM__^^..^^™«.,..     103
 10,   False ,.«..«.™™>.-^.	,	.	_„_.	™™™™,«^™^™™™m_™™»     104
 11.   c _„»,.„„,„,	,	.	___	_	__—_____	103
 12.   e .^	__	__________________	_	_	__     105
 13.   b «..«™_._.™~^...™__™	______«________.	.	^	™.™     105
 14.   d .	~.	.	^^«™™™™™™™™™^™^..^™.,™™^..™«._™_._™™™m_™-^™_..     106
 15.   a	.	.	.	,—™	_	_	,	.	,	_»_	106
 16.   False
 17.  g	™	—^^.	_—_.„._—™^	.	________     119
 18.  b ._™.	—-	.	™	..	—.	.	.™.~™^..™..     121
 19.  True ..^...^M.»««~.^^«^»™M^..-..»«..~™.«..««....»«™».™™..«»....»^«.M™.™^.M..^....m.™TO..     12?
 20.  Fate .^..M....™.....™.«™......™....«.~«.	.™M,......^,.,.™^..«,.«.........«..M™.....™™.M.M..^^.....     124
 21.  True..........	[[[	™..™«..^^.™     127
 22.  True	.	.	™««	.	.	     129
 23.  a	.	,	.	     97
 24.  b.	,	....	„	     100

 26.  c	-	.	..	.	.	....	........	..........	.	....     Ill
 27.  c ™.^..TO»...™..«»..™^^.....™~_.™».M..	._~_~..~~.	.	^....™..^^«.™~.™«_™.M     111
28.  b _.	......	~~~_~	.	_~__	^~,.	^™™_»__~_..™^..m..	^..^     100
29.  a „	.	.....	,	,	...-..,	......	-	—	.—.-..—	.	^     97
30.  c	„.„,„„.	.	.—_	™	...	     102

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                            Section  4
           Exposure and  Risk Assessment
 Heading Assignment

 Pages 146-171 of EPA 450/2-89-010, "Assessing Multiple Pollutant Multiple Source Cancer Risks
 from Urban Air Toxics."
 Reading Assignment Topics

   *  Use of and issues associated with exposure and risk assessments in air toxic studies
   *  Comparison of approaches to exposure and risk interpretation and assessment
   *  Insights into the use of exposure and risk assessment in air toxic studies
Learning Goal and Objectives

                                   Learning Goal

To familiarize you with the role of and methodologies used in exposure and risk estimation in
urban air toxics assessment.

                                 Learning Objective

When you have completed this section, you should be able to:

  •  identify the various ways risks have been estimated, reported, and compared
  *  identify assumptions and uncertainties associated with exposure and risk estimates


Reading Guidance

  •  When you  have finished the reading assignment, complete the review exercise for Section 4.
     It begins on the following page.
  •  After you have answered the review exercise questions, check your answers "The correct
     answers are listed on the page immediately following the review exercise,
  *  For any review exercise questions that you answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page.
  *  After you have reviewed your incorrect answers (if any), proceed to Section 5 of this
     guidebook.
                                          4-1

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                              Review Exercise
Now that youVe completed the assignment for Section 4, please answer the following questions.
These will help you determine whether or not you are mastering the material

                                                     	issue that has been
1.   Estimating exposures and risks from air toxics is a	
    addressed in a	manner.

    a.  simple/highly simplified
    b.  simple/highly sophisticated
    c.  complex/highly simplified
    d.  complex/highly sophisticated

2.   True or False? Field-oriented studies concerned with ambient outdoor air concentrations of
    air toxics typically include exposure contributions from residential, commercial, occupational,
    and transportation-related microenvironraents.

                                                                   	, while the
 3.   The Total Exposure Assessment Methodology is investigating more	
     Integrated Cancer Project is investigating	•

     a.  .comprehensive exposures/individual microenvironments.
     b.  individual microenvironments/comprehensive exposures.

 4..  Most studies calculated areawide cancer incidence using the same basic formula. This
     formula was:
    b.
                 Ambient

               Concentration


                 Ambient

               Concentration


                 Ambient

               Concentration


                 Ambient

               Concentration
      Number of People
      Exposed to Ambient
         Concentration

     Cancer Unit

     Risk Factor
                                     Number of People

                                    Exposed to Ambient
                                      Concentration
     Cancer Unit

+    Risk Factor


 Number of People

Exposed to Ambient
 Concentration

     Cancer Unit

x    Risk Factor
                                                                     Number of People
   Cancer Unit      Square miles of

x   Risk Factor  x  Geographic area   x  Exposed to Ambient
                     of Study           Concentration
5.   In the equation in Question 4 above, the areawide cancer incidence is computed by summing
    over each	and each	.

    a.   subarea/pollutant
    b.   pollutant/source category
    c.   subarea/source category
                                             4-2

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 6.   True or False?  Most of the studies used cancer unit risk factors developed by EPA's Cancer
     Assessment Group?

 7.   The health hazards Index is an indicator of concern associated with	effects.

     a.  cancer
     b.  noncancer
     c.  cancer and noncancer

 8.   If the health hazard index exceeds i, the concern is	if the no-effect threshold
     were exceeded by the same amount by an individual pollutant

     a.  less than
     b.  the same as
     c  greater than

 9.   Most studies emphasized estimating	and only a subset emphasized estimating
     a.  areawide annual population exposures/maximum exposed individuals
     b.  maximum exposed individuals/areawide annual population exposures

10.  Pollutant ranking involves the ranking of the relative importance of pollutants in terms of:

     a.  the number of sources emitting each pollutant
     b.  the contribution of each pollutant to ambient concentrations
     c  the contribution of each pollutant to potential risk
     d.  all of the above

11.  Source categories can be	, such as	 vs	and	vs	.
     a.  broad, mobile/stationary, industrial/hon-industrial
     b.  narrow, industrial/non-industrial, commercial/residential
     c  broad, area/point, mobile/stationary
     d.  narrow, mobile/stationary, industrial/rion-industrial

12.   Culpability analysis applies to:

     a.  individual pollutants or groups of pollutants
     b.  particular sources or source groups
     c,  a and b

13.   Examining of the ratio of MEI to average values is an example of:

     a.  ranking  the relative importance of pollutants
     b.  ranking  the relative importance of sources or source categories
     c.  culpability analysis of sources or source categories
     d.  evaluating variations in exposures and risks

14.   The total number of cancer cases	(is/Is not) dependent on the size of the exposed
     population and the average probabilistic risk	(is/is not) dependent on the size of
     the exposed  population.
                                                4-3

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 For questions 15 through 20, which of the following methodological issues are associated with
 exposure assessments and which with risk assessments?  (Circle your answer)

 15.   Selection of study boundaries                  .                  Exposure       Risk

 16.   Addiiivity assumptions                                          Exposure       Risk
                        *
 17.   Location of monitoring sites                                    Exposure       Risk

 18.   Development of dose-response data                              Exposure       Risk

 19.   Assumption of constant exposures for 70 years                    Exposure       Risk

 20.   Population  mobility                                            Exposure       Risk

 21.   The HEM uses a (polar coordinate/rectangular grid) system to link population and exposure
      data,

 22.   SHED is considered (less accurate than, about the same as, more accurate than) SHEAR for
      estimating maximum lifetime risks, but (less accurate, not significantly more accurate) than
      SHEAR for estimating aggregate incidence.

 23.   True or False? Based on empirical evidence, air pollutant concentration in the center of a
      city are about the same as at the outskirts of the city because of regional mixing.

 For questions 24 through 27, which  of the following statements concerning the modified NEM are
 true and which are false?

 24.   Photochemical reactions are taken into account                   T     F

 25.   Predicted exposure  levels are those resulting
      from direct exhaust emissions.                                    T     F

 26.   Assumes pollutant of interest has emission formulation
      and dispersion characteristics similar to CO.                       T     F

 27.   Uses an activity pattern model to simulate day-to-day
      activities.                                                      T     F

 28.   Two examples of microenvironments are:

     a.   indoors, automobiles
     b.   automobiles, parks
     c.   parks, office
     d.   gas station, indoors

 For questions 29 through 32, True or False? The unit risk factor ...

29.  represents ihe probability of contacting cancer                     T      F

30.  from constant inhalation and ingestion                            T      F

31.  over a nominal lifetime of 65 years                               T      F

32,  of 1 jig/m3.                                                     T      F

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33.   For most studies of carcinogenicity at the low levels encountered in ambient air, the shape of
      the dose-response function is assumed to be:

      a.   linear
      b.   log-normal
      c.   normal
      d.  varies with the pollutant

34.   The following formula is used to derive potency estimates for	.
      Estimated                Known                Bioassay PotencyUmMUld
      Human RiskUla(Iuld  =      Human RiskT)IMe(,   x
                                                      BioassayPotencyT<-aJQldoa>en

      a.  CAG does-response relationships
      b.  Structure-activity method
      c  comparative risk method

35.   One advantage of the (comparative risk method, Structure-Activity Method) is that it directly
      evaluates complex organic mixtures, potentially taking into account synergistic or antagonistic
      effects.

36.   True or False? Even for dissimilar endpoints, the assumption of additivity is appropriate for
      noncancer health effects.

37.   True or False? Data are available to determine the relationship between health effect and
      the length  of time the threshold is exceeded for many pollutants.

38.   True or False? Threshold levels for the same pollutant may vary among individuals or across
      population groups.

39.   True or False? Most studies of noncancer health effects disregard the dose-response curve,
      focusing only on whether the threshold value is exceeded.

40.   True or False? Because health data on noncarcinogens are limited, EPA has endorsed the
      use of industrial exposure standards for use in ambient air toxic risk assessments.

41.   True or False? The accuracy of potencies has been an important general issue in ranking the
      relative significance of pollutants.

42.   One problem facing  the ranking of individual pollutants is speciation.  The problem of
     speciation in this regard deals with:

     a.   estimating the quantity of individual components of total emissions of a compound.
     b.   assigning potency factors to each individual component of total emissions of a
         compound.
     c   determining the  relative contribution of sources to the total emissions of a compound.

43.  True or False?  Modeled exposures  tend to be consistently (higher/lower) than monitoring
     concentrations of the same pollutant because of (uncertain estimates of emission factor,
     inability to model background concentrations).
                                                4-5

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                     Review  Exercise  Answers
                                                                         Page(s) of
                                                                         Urban Air
                                                                         Toxics Manual
 1.
 2.
 3.
 4.
 5.
 6.
 7.
 8,
 9.
 10,
 n.
 12.
 13.
 14.
 IS.
 16.
 17.
 18.
 19.
 20.
 21.
 22.
 23.
 24.
 25.
 26.
 27.
 28.
 29.
 30.
 31.
 31
 33.
 34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
 c.,
 False..,
 a.,
 c	
 a
 True ...............
 b „	
 b	.	
 c
 c
 b
 is, is not
 exposure ______
 risk. -------
 exposure
 risk ________
 risk. —
 exposure..
                                                                         146
                                                                         146
                                                                         146
                                                                         147
                                                                         147
                                                                         147
                                                                         148
                                                                         148
                                                                         148
                                                                         148
                                                                         149
                                                                         149
                                                                         149
                                                                         149
                                                                         149
                                                                         156
                                                                         ISO
                                                                         155
                                                                         156
                                                                         152
polar coordinate.....	.—......	.	..	    150
                                                                         151
                                                                         152
                                                                         153
                                                                         153
                                                                         153
                                                                         152
                                                                         154
                                                                         155
                                                                         155
                                                                         155
                                                                         155
                                                                         156
                                                                         157
comparative risk method......—	.....	•—.......—.	.....»    158
more accurate, not significantly more accurate............
False	
False.	.	
True ...........
True	
True	
a
True
False
False
True
a	
c .......
False	
False.........
True	
True ..........
False	
True	
b	
                                                                         158
                                                                         158, 159
                                                                         159
                                                                         159
                                                                         159
                                                                         162
                                                                         162
higher, inability to model background concentrations	    163

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                            Section   5
              Control  Strategy  Simulation
                          and  Evaluation
 Reading Assignment

 Pages 179-190 of EPA-450/2-89-010, "Assessing Multiple Pollutant Multiple Source Cancer Risks
 from Urban Air Toxics."
Reading Assignment Topics

   •  Use of control strategy and evaluation in urban air toxics assessments
   *  Comprehensive vs. site-specific strategy simulation
   •  Control strategy simulation procedures in the S City Controllability Study
   •  Insights on control strategy simulation and evaluation
Learning Goal and Objectives

                                  Learning Goal

To recognize that the potential risk reductions achievable through alternative control measures is
the principal objective of the methodologies and studies reviewed.

                                Learning Objectives

When you have completed this section you should be able to:

  •  recognize that the concept of co-control is an important consideration in air toxic control
    strategy evaluation;
  •  recognize that control strategy analyses are conducted on comprehensive and site-specific
    scales;
  •  identify the differences between comprehensive and site-specific control strategy analyses;
  •  know how the regulatory impact model (RIM) assists  in control strategy simulation and
    evaluation;
  •  realize that the basis of derived cost-effectiveness values is as important as the values
    themselves; and
  *  recognize that incidence reduction can be based on both areawide incidence and risk to the
    most exposed individual (MEI).
                                      5-1

-------
Reading Guidance

  *  The reading assignment discusses the concept of risk assessment vs. risk management.  Risk
     assessment is the use of the factual base to define the health effects of exposure of
     individuals or populations to hazardous materials.  Risk management is the process of
     weighing policy alternatives and selecting the most appropriate regulatory action, integrating
     the results of risk assessment with engineering data and with social, economic and political
     concerns to reach a decision.
  *  "Co-control" potential is discussed as an important factor in control strategy evaluation. In
     this context, co-control is  defined as the extent to which controls designed for ozone, PMj^
     or other criteria pollutants also control air toxics,
  •  The acronym IEMP refers to the  "Integrated Environmental Management Program*. Within
     target cities (such as Philadelphia, Baltimore, and Santa Clara), specific sites were chosen for
     the IEMP analyses.
  •  When you have finished the reading assignment, complete the review exercise for Section 5.
     It begins on the following page.
  •  After you have answered the review exercise questions,  check your answers.  The correct
     answers are listed on page immediately following the review exercise.
  •  For any review exercise questions that you answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page.
  •  After you have reviewed your incorrect answers (if any), proceed to Section 6 of this
     guidebook.
                                            5-2

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                            Review Exercise
Now that youVe completed the assignment for Section 5, please answer the following questions.
These will help you determine whether or not you are mastering the material.

 1.   	are suitable for control analyses, because emissions can reasonably be projected into
     the future, both as a function of anticipated growth in an area and as a function of
     alternative control measures that may be applied,

     a.  Ambient air monitoring studies
     b.  Dispersion modeling studies

 2,   Once the control analysis is completed,	can use the information to prioritize various
     alternative measures, based upon risk reduction.

     a.  risk managers
     b.  risk assessors

 3.   True or False? The concept of co-control is an important  consideration in control strategy
     evaluation because measures designed for air toxics control may help "sell" certain criteria
     pollutant control measures that may otherwise have marginal acceptability on their own
     merits.

4.   What are the two types of control strategy analyses employed in the studies reviewed?

     a.  co-control and separate control
     b.  comprehensive and site-specific
     c.   maximum exposed individual and aggregate

5.   A	analysis was employed in the 5 City Controllability Study and a	analysis was used
     in the IEMP evaluations.

     a.   co-control/separate control
     b.   comprehensive/site-speeific
     c.   maximum exposed individual/aggregate

6.   True or False? In both types of control strategy analyses employed, emissions projections
     are  made corresponding to the control scenarios simulated.

7.   Fundamental differences between the two types of control strategy analyses include the
     following:

     a.   the extent of source coverage
     b.   the consideration of multiple vs.  single control  strategies
     c.   the number of individuals living within the area of concern
     d.   the incorporation of growth and plant retirement into future projections of emissions
         and  risk
     e.   all of the above
     f.   a, b, and c
     g.   a, b, and d
                                           5-3

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 8.    In the 5 City Controllability Study, a period of	years was considered Jong enough that new
      source growth and old source retirement could be factored into the analysis.

      a.   5
      b.   10
      c   15
      d.   20

 9.    True or Fake? When future projections were made in the 5 City Controllability Study,
      control efficiencies applied to existing sources vs. new growth and replacement growth
      sources were considered to be the same.

 10.   True or False? The regulatory impact model (RIM) is used to project emissions from a base
      year inventory by incorporating different combinations of control measures.

 11.   True or False? In this analysis, RIM calculates PM and VOC reductions and assumes that
      paniculate toxics and  toxic VOC are controlled the same extent.

 12.   Because the  5 City Controllability Study was a broad national scoping study, several
      important assumptions were made. Which of the following assumptions was not important?

      a.   The baseline emissions and control efficiency are assumed to be accurate.
      b.   Control  levels of toxics organics and toxic PM are assumed proportional to control levels
          of VOC and PM,  respectively.
      a   Assumed that EPA would focus control of toxic air emissions on Section 112 of the
          Clean Air ACL
      d.   Control  measures  are assumed to be applicable to the targeted sources, without regard
          for technical feasibility on a case-by-case basis.

 Match each of the following point and area source categories with its most  likely control option.
 (Questions  13-17).

 13. Degreasing	          a. Leak detection and repair program
 14. Refinery	            b. Inspection and maintenance, carbon adsorption
 15. Gasoline Marketing	  c. Cover during the idle time
 16. Dry Cleaning	        d. Secondary seals
 17. Storage Tanks	       e. Stage II controls

 18.  True or False? Cost-effectiveness is  measured in  terms of control strategy cost per reduced
     cancer case.  Generally, the reductions in the incidence rate are calculated from average risk
     values (i.e., the number of excess  cancer cases divided by the overall study population).

 19.  True or False? Taken  together, risks to the most exposed individual (MEI), as well as
     areawide cancer incidence, offer qualitative insight into the merits of various controls. The
     determination of cost-effective controls based on both approaches usually results in similar
     conclusions.

20.   True or False? Generally, the studies reviewed focused on areawide cancer incidence
     reductions. While MEI reductions can also readily be projected,  they  are more difficult to
     evaluate from a cost-effectiveness standpoint

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                       Review Exercise Answers
                                                                                 Page(s) of
                                                                                 Urban Air
                                                                                 Toxics Manual

 1.   b	..	     173
 2.   a .,	.	~	-	     174
 3.   True.	»	.	     174
 4    b     ,„„.„,»„.„.„.„,„.	„.,.„		„	...„...„	™.~	......................................     174
 5.   b	.	.	     174-175
 6.   True		„			     175
 /,   J* „„„»,*,»,»«,»***••••»:»»»•.**.»»*..••»*•*.»«•»«**»••*.»»•..•«*.«*••.•***»*»*                                     A * tf
 8.   c		»	.	.	     175-176
 9.   False	.	.	—~	     176
10.   True....	.	.	.	-	     176
11.   True	.			.	     178
12.   c „	......   ,...„.„........	...........................	.....................................	..	..™««....     179
13.   c ....................		~~	.	.	........™............™.........«-....M..............»......     181
14.   a		.„	.	     181
15,   e	.	.	M	.	     182
16.   b „	„.,	„	„..„„„„..„.„.„„„„„....„„	ra..	.	.™™.««_.«.................^^^...™»..     182
17.   d	     181-182
18.   True.	......	~	.	     185-186
19.   False.	.........	...	...	.....	.	.....	.	.................	...	.....	_™     186
20.  True			-	•	     188-190
                                             5-5

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                            Section   6
             Computerized  Data  Handling
 Reading Assignment

 Pages 191-209 of EPA 450/2-S9-010, 'Assessing Multiple Pollutant Multiple Source Cancer Risks
 from Urban Air Toxics.*
 Reading Assignment Topics

   •  Identification of considerations in using computerized data handling systems
   *  Identification of available computerized data handling systems
   »  Insights on computerised data handling
Learning Goal and Objectives

                                  Learning Goal

To familiarize you with the availability, capabilities, and considerations of computerized data
handling systems in urban air toxics assessment


                                Learning Objectives

When you have completed this section, you should be able to:

  *  describe the basic considerations in selecting a data handling system
  *  identify various data handling systems  available
  *  identify various cost saving techniques


Reading Guidance

  •  When you have finished the reading assignment, complete the review exercise for Section 6.
     It begins on page 6-3.
  »  After you have answered the review exercise questions, check your answers.  The correct
     answers are listed on the page immediately following the review exercise,
  *  For any review exercise questions that  you answered incorrectly, review the page(s) of the
     reading assignment indicated on the answers page.
                                      6-1

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After you have reviewed your incorrect answers (if any), take the final examination for the
course.  Follow the direction listed in the Course Introduction section of this guidebook.
Your course grade results will be mailed to you.
                                       6-2

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                            Review Exercise
 Now that you've completed the assignment for Section 6, please answer the following questions.
 These will help you determine whether or not you are mastering the material
                       •*

 1.  True or false? The development of exposure and risk estimates in multi-source, multi-
     pollutant assessments involves extensive data handling.

 2.  The best time for a study manager to consider the data handling aspects of an urban air
     toxics study is:

     a.   After the initial data have been gathered so an evaluation can be made of data handling
         needs.
     b.   At the outset of the study, as pan of the overall study protocol.

 3.  Which of the following is true?

     a.   Development of specialized data  handling software is expensive and time consuming.
     b.   Utilization of existing software can help avoid expenses.
     c.   Most of the studies reviewed developed their own capabilities.
     d.   all of the above.
     e.   a and b.
     £   a and c,

 4.   Data handling complexity in ambient air monitoring studies is (more complex, less complex,
     about the same) as in emission inventory/dispersion modeling studies.

 5.   Ambient air concentrations are applied to population data to estimate population-averaged
     exposures in:

     a.   emission inventory/dispersion modeling studies
     b.   ambient air monitoring studies
     c.   both a and b

 6.   True or False? Only a few State and  local agencies can access EPA's mainframe computers
     through remote terminals.

 7.   The extent to which exposure and risk estimation and control strategy evaluation can be
     arrived at on personal computers depends on:

     a.  the number of pollutants
     b.  the sources of pollution
     c  the spatial resolution of the analysis
     d.  all of the above
     e.  a and b

8.    True or False?  Regardless of the extent of mainframe  involvement in 'number crunching,"
     persona] computers can be useful for analyzing summary data  sets  created by the mainframe
     and for tailoring special reports and graphics.

9.   True or False?  Data summaries can be produced using spreadsheets and database
    management programs that are commonly available for most persona! computers.


                                          6-3

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 10.   Many studies used PIPQUIC to:

      a.  store their data
      b.  develop estimates of exposure
      c  develop estimates of risk
      d.  all of the above
      e.  a and b
      £  b and c

 11.   PIPQUIC was developed tor.

      a.  The South Coast MATES
      b.  The IEMP studies
      c  The Southeast Chicago study
      d.  The 5-City Controllability study

 12.   PIPQUIC executes which two EPA models:

      a.  ISCLTandlSCST
      b.  ISCLT  and CDM
      c.  ISCLT  and HEM
      d.  CDM and HEM

 13.   True or False? PIPQUIC allows the user to run his/her own models in lieu of the two EPA
      already in PIPQUIC

 14.   PIPQUICs Tool 440 does which of the following:

      a.  create a broad range of study maps
      b.  allows the user to rank order his/her source and emission data
      c.  pinpoint sites of maximum concentrations.

 15.   PIPQUICs  Tool 450 does which of the following:

     a.  create a broad range of study maps
     b.  allows the user to rank order his/her source and emission data
     c.  pinpoint sites of maximum concentrations.

 16.  PIPQUICs  Tool 453 does which of the following:

     a.  create a broad range of study maps
     b.  allows the user to rank order his/her  source and emission data
     c.   pinpoint sites of maximum concentrations.

17.  In addition to sites of maximum concentration, PIPQUIC allows the user to pinpoint sites of:

     a.   individual risk
     b.   aggregate cancer incidence
     c.   a and b
     d.   neither a nor b

18.  True or False? PIPQUIC Tool 453 allows the use to assess the impact of each pollutant and
     source at any receptor within the study area.

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 19.  True or False?  PEPQU1C is designed so that 3 user can download maps of graphs to a PC
      and then re-create and edit  them without having to re-enter PIPQU1C

 20.  Of the studies reviewed, which two were identified as developing their own data handling
      capabilities?

      a.   the 5 City Controllability Study and the Southeast Chicago Study
      b.   the Southeast Chicago Study and the South Coast Study
      c   the South Coast Study and the 5 City Controllability Study

 21,  True or False?  RIM allows the user to project future emissions and cancer incidence by
      simulating various hypothetical growth scenarios.

 22.  Which of the following (is) are PC-based model(s):

      a.   HEM/SHEAR
      b.   SCREAM
      c   RIM
      d.   all of above

 23.  True or False? The SCREAM model, which was used for the Los Angeles area, is applicable
      to other geographical areas.

 24.  The practice of normalized modeling is a cost-saving technique because:

      ».   it aggregates similar sources
      b,   reduces the number of dispersion model runs needed
      c.  reduces the time it takes to make a dispersion model ran

 25.  True or False? Most of the  studies reviewed did not use normalized modeling.

 26.   The cost and execution time  of modeling potet sources is	(much less than,
      about the same as, much greater than) for modeling area sources.

 27.   Data handling for the ambient air monitoring studies reviewed is being conducted using:

      a.  dBase*
      b.  Lotus 1A30
      c.  individually-designed spreadsheets,

 28.   Various functions that can be done more efficient and more readily OB personal computers
      than on a mainframe computer are:

      a.  preparation of emission data
     b.  dispersion models
     c.  editing of various outputs
     d.  creation of summaries and graphs
     e.  all of the above
     L   a, b, c
     g. a,c,d
     h.  b, c,d
     L  a and d

29.  True or False? Normalized modeling assumes a linear  relationship between emission
     changes and model-predicted  concentrations.

                                           6-5

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30.  If the release specifications change as emission change (e.g., a control device may alter a
     plant's stack/exhaust parameters as well as its emissions), then which of the following cost-
     saving techniques may no longer be valid:

     a.  normalized modeling
     b.  modeling small point sources as area sources
     c.  both a and b

31.  True or Fate? Modeling small point sources as area sources may change the exposures
     resulting from those sources.
                                           6-6

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                     Review  Exercise Answers
                                                                                 of
                                                                          Urban Air
                                                                          Toxics Manual
 1.  -True.—-»	;	_	,.—-—•.	,	—	_	,	     191
 2.   b __™__~..~—...	—	_—,—_—_—	191
 *9   jgt                                                                         ^Ql
 •?*   W *u» inl * »i*i in 11 mi 'D-ii riririnnr T» •••••-• • • • • m* i « * 11 • i *• aniiii i «i • •• • «m •• • • • t • •• n n • •••••• i • * •• •«••» » • • I in m mm TTT r im mnrnr irimi IT i Ttn_ii irmnmr n: trill I'Trnm * iiim mrm 11111.1 ILJ.     ijFi
 4.   less complex ™~~~_~~	_——.—_——_.	,	„	,——__     192
 5.   c ™~,	,	~	,—_	-_—_	—	~     192
 6.   False——	,	.	,	—_     192
 7.   d _™~_—«	—.—.	.	,-^_,
 g.   Tn« ____—	-.^	.	«-.	-_	™™_^	«.	.	«_     192,193
 9.   Tree _—«——.	.	.	,	,	—	_-__	_     193
1ft   d _—_—«.—,	„—.	.—_	_™__	.	     193
It   b™~~—~~——	~~	,	»—.—.—~----_~---_	,~
12.  b	™™___-™™	.	,	,	_««.	.	,	—_	™™_     193
13.  Tr^ -————	:	,—_—.	—~~	~	—     193
14.  b _^__	.—	—	_	~——.—-     194
15.  • .	_	.	~	—.	.	™     194
16.  c _	,	.	.	.	,	199
17." c ^—.	.	,—,	,	,	,	.—     199
18.  True ——.	,	,	.——	:	     199
19.  True		.	.	.     199
m  c_	.	—	.—     199
21.  False.....__-_	.	~..~~......—~~~.~~	.„„	»	.	.^_>__._w_™..     199
22.  c ......^^.^............-~—.~..-~-™—	_»~w~-~_	—.	^_..~^...	     199
23.  False ....	—^	.	-	—.	-	~—	     205
24.  b	......	™«.™	...~	..	-	•	....     205
25.  False	........	~	.....~.^._......	«.™_...	„	.^.	.~.~~..«...     205
26.  m.uch greater than ...U____W....._«U..U.._..«....._........M..._«..........«......»~»...W..>»_«~_~..     205
27.  b .„„„.......„	~~	.	.	—	.	     206
28.  g		—.	     206
29.  True .	.	-.-—	™	-     206
30.  a -—..».	.~~	.........	.	.	.	-	«     206
31.  True .....„«_».«....«....	.,.™..«,.......,.«......™™..™.	_~.~»«~..~~»~.	.........     206
                                         6-7

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                                    TECHNICAL REPORT DATA
                             (Please read Inuructions on the reverse before completing)
  1. REPORT NO.
                               2.
                                                            3. RECIPIENT'S ACCESSION-NO.
 4, TITLE AND SUBTITLE
   APTI  Correspondence  Course 404 - Assessing  Multiple
   Pollutant Multiple Source Cancer Risks  from Urban
   Air Toxics - Guidebook
              5, REPORT DATE
               October 1990
              6. PERFORMING ORGANIZATION CODE

               OAQPS
 7. AUTHOR(S)
              8. PERFORMING ORGANIZATION REPORT NO,
 t. PERFORMING ORGANIZATION NAME AND ADDRESS
   Pacific Environmental  Services
   3708 Mayfair St., Suite 202
   Durham, NC  27707
              10. PROGRAM ELEMENT NO.
              11, CONTRACT/GRANT NO.
                68-02-4393
 12. SPONSORING AGENCY NAME AND ADDRESS
   Air Pollution Training Branch
   Air Quality Management Division
   Office of Air Quality Planning and Standards
   Research Triangle Park, NC  27711
              13. TYPE OF REPORT AND PERIOD COVERED
              14. SPONSORING AGENCY CODE
 15. SUPPLEMENTARY NOTES
  EPA Project Officer  for this Guidebook is Charles  0.  Pratt
  MD-17,  Research Triangle Park, NC  27711           	
 16. ABSTRACT
           This Guidebook  is used in taking APTI  Course CC:404, "Assessing Multiple
           Pollutant Multiple Source Cancer Risks from Urban Air Toxics."  It is
           used in conjunction with EPA Publication  EPA-450/2-89-Q10,  "Assessing „
           Multiple Pollutant Multiple Source Cancer Risks from Urban  Air Toxics.
           This Guidebook  directs the student through the supplementaltext.   Questions
           and answers help the student understand the material presented.
           Major topics  include:  Summary of Urban  Air Toxics Assessment  Studies,
           Monitoring Approaches, Exposure and Risk,  Control Strategy Evaluation,
           Data Handling,  and Evolving Technologies.
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.IDENTIFIERS/OPEN ENDED TERMS
                           c.  COSATI Field/Group
  Self-Instructional Guidebook
  Air Toxics
  Air Toxics  Cancer Studies
  Urban  Soup
  Guidebook
                                                                             51
 8. DISTBI8UT1ON STATEMENT
1S. SECURITY CLASS (TMt Report)
   Unclassified
21. NO. OF PAGES

      52
                                              20. SECURITY CLASS (Thil page)

                                                 Unclassified
                                                                          22. PRICE
EPA Form 2210-1 (»-73)

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