United StitM
4>EPA
           Agency
           Offfce of
           Toxic Substarwsw
           Washington, D.C. 20480
Methods for Assessing
Exposure to Chemical
Substances

Volume 7

Methods for Assessing
Consumer Exposure to
Chemical Substances

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                                       EPA 560/5-85-007
                                       APRIL  1987
       METHODS  FOR  ASSESSING  EXPOSURE
           TO CHEMICAL  SUBSTANCES
                  Volume  7
  Methods for Assessing Consumer Exposure
          to Chemical  Substances
                    by
Patricia D.  Jennings, Karen A.  Hammerstrom,
 Leslie Coleman Adkins,  Thompson Chambers,
             Douglas A. Dixon
        EPA Contract No.  68-02-3968



              Project Officer

            Elizabeth F. Bryan
       Exposure Evaluation Division
        Office of Toxic Substances
          Washington,  D.C.   20460
   U.S. ENVIRONMENTAL PROTECTION AGENCY
 OFFICE OF  PESTICIDES AND  TOXIC  SUBSTANCES
         WASHINGTON, D.C.   20460

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11

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                                DISCLAIMER
    This document has been reviewed and approved for publication by the
Office of Toxic Substances, Office of Pesticides and Toxic Substances,
U.S. Environmental Protection Agency.  The use of trade names or
commercial products does not constitute Agency endorsement or
recommendation for use.
                                   ill

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                                 FOREWORD
    This document 1s one of a series of volumes, developed for the U.S.
Environmental Protection Agency (EPA), Office of Toxic Substances (OTS),
that provides methods and Information useful for assessing exposure to
chemical substances.  The methods described 1n these volumes have been
Identified by EPA-OTS as having utility In exposure assessments on
existing and new chemicals 1n the OTS program.  These methods are not
necessarily the only methods used by OTS, because the state-of-the art 1n
exposure assessment 1s changing rapidly, as Is the availability of
methods and tools.  There 1s no single correct approach to performing an
exposure assessment, and the methods 1n these volumes are accordingly
discussed only as options to be considered, rather than as rigid
procedures.

    Perhaps more Important than the optional methods presented 1n these
volumes 1s the general Information catalogued.  These documents contain a
great deal of non-chem1cal-spedf1c data which can be used for many types
of exposure assessments.  This Information Is presented along with the
methods 1n Individual volumes and appendices.  As a set,  these volumes
should be thought of as a catalog of Information useful 1n exposure
assessment, and not as a "how-to" cookbook on the subject.

    The definition, background,  and discussion of planning exposure
assessments are discussed 1n the Introductory volume of the series
(Volume 1).  Each subsequent volume addresses only one general exposure
setting.  Consult Volume 1  for guidance on the proper use and
Interrelations of the various volumes and on the planning and Integration
of an entire assessment.

The titles of the nine basic volumes are as follows:

Volume 1 Methods for Assessing Exposure to Chemical Substances
         (EPA 560/5-85-001)

Volume 2 Methods for Assessing Exposure to Chemical Substances 1n the
         Ambient Environment (EPA 560/5-85-002)

Volume 3 Methods for Assessing Exposure from Disposal  of  Chemical
         Substances (EPA 560/5-85-003)

Volume 4 Methods for Enumerating and Characterizing Populations Exposed
         to Chemical Substances  (EPA 560/5-85-004)

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Volume 5   Methods for Assessing Exposure to Chemical Substances In
           Drinking Water (EPA 560/5-85-005)

Volume 6   Methods for Assessing Occupational Exposure to Chemical
           Substances (EPA 560/5-85-006)

Volume 7   Methods for Assessing Consumer Exposure to Chemical Substances
           (EPA 560/5-85-007)

Volume 8   Methods for Assessing Environmental Pathways of Food
           Contamination (EPA 560/5-85-008)

Volume 9   Methods for Assessing Exposure to Chemical Substances
           Resulting from Transportation-Related Spills (EPA 560/5-85-009)

    Because exposure assessment 1s a rapidly developing field, Its
methods and analytical tools are quite dynamic.   EPA-OTS Intends to Issue
periodic supplements for Volumes 2 through 9 to describe significant
Improvements and updates for the existing Information, as well as adding
short monographs to the series on specific areas of Interest.  The first
four of these monographs are as follows:

Volume 10  Methods for Estimating Uncertainties  In Exposure Assessments
           (EPA 560/5-85-014)

Volume 11  Methods for Estimating the Migration  of Chemical  Substances
           from Solid Matrices (EPA 560/5-85-015)

Volume 12  Methods for Estimating the Concentration of Chemical
           Substances in Indoor A1r (EPA 560/5-85-016)

Volume 13  Methods for Estimating Retention of Liquids on Hands
           (EPA 560/5-85-017)
                                    Elizabeth F.  Bryan,  Chief
                                    Exposure Assessment  Branch
                                    Exposure Evaluation  Division (TS-798)
                                    Office of Toxic Substances
                                    vi

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                             ACKNOWLEDGEMENTS
    This report was prepared by Versar Inc. of Springfield, Virginia, for
the EPA Office of Toxic Substances, Exposure Evaluation Division,
Exposure Assessment Branch (EAB) under EPA Contract Nos. 68-01-6271 and
68-02-3968.  The EPA-EAB Task Managers for this task were Karen A.
Hammerstrom and Stephen H. Nacht; the EPA Program Managers were Michael
A. Callahan and Elizabeth F. Bryan.  The support and guidance given by
these, and other EPA personnel, is gratefully acknowledged.

    A number of Versar personnel have contributed to this task over the
period of performance, as listed below:
    Program Management

    Task Management


    Principal  Investigator

    Technical  Support



    Editing


    Secretarial/Clerical
-  Gayaneh Contos

   Patricia Jennings
   Douglas Dixon

-  Patricia Jennings

-  Leslie Adkins
   Thompson Chambers
   John Doria

-  Juliet Crumrine
   Barbara Malczak

-  Shirley Harrison
   Sue Elhussein
   Mary Ann Rish
   Kathy Zavada
   Franklin Clay
   Lucy Gentry
   Donna Barnard
   Lynn Maxfield
   Kammi Johannsen
   Jan Hunter
   LaVonnia Brown
                                   vii

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V111

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                             TABLE OF CONTENTS
                                                                 Page  No.

1.  INTRODUCTION  	;	      1

    1.1   Background and Purpose  	      1
    1.2   Consumer Products Considered by This Methods
          Report  	      1
    1.3   Overview of Methodological Approach  	      2

2.  PHYSICAL-CHEMICAL PROPERTIES	    15

    2.1   General Property Information 	    15
    2.2   Data Gathering 	    15

          2.2.1   Sources of Experimental Data	    15
          2.2.2   Methods for Estimating Physical-Chemical
                  Properties 	    21

    2.3   Summary 	    21

3.  PRODUCT-SPECIFIC DATA REQUIRED TO ASSESS EXPOSURE  	    25

    3.1   Amount of Chemical Substance Applied Directly to
          Surfaces 	    25
    3.2   Amount of a Chemical  Substance Released by Use
          of Aerosol  and Pump Spray Products and by Pouring
          or Spilling Liquids and Powders 	    31
    3.3   Identification of Consumer Products and
          Formulations  	    34

4.  METHODS FOR ESTIMATING RELEASE OF CHEMICAL SUBSTANCES
    FROM CONSUMER PRODUCTS AND  CONCENTRATIONS OF CHEMICAL
    SUBSTANCES IN INDOOR AIR 	    45

    4.1   Overview of Mechanisms of Chemical Release and
          Factors Affecting Concentrations  to Which Consumers
          are Exposed 	    45
          4.1.1   Chemical  Release Mechanisms 	    46
          4.1.2   Factors Affecting Exposure Concentrations ..    48

    4.2   Monitoring  Data 	    49
    4.3   Methods to  Estimate Release of  Chemical Substances
          from Consumer  Products 	    49
                                    ix

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                       TABLE OF CONTENTS (continued)

                                                                 Page  No.

         4.3.1  Release  Rate of Chemical Substances  in
                Aerosol  Consumer  Products  	     50
         4.3.2  Release  Rate of Chemical Substances  from
                Liquid Films Applied to Surfaces  	     51
         4.3.3  Chemical Release  from  Liquids and Solids  	     60

    4.4  Methods for Estimating Concentrations  in Indoor  Air  .     64

         4.4.1  Concentrations Resulting from Instantaneous
                Releases of Chemical Substances  	     67
         4.4.2  Concentrations Resulting from Continuous  Release
                of Chemical Substances 	     73
         4.4.3  Concentrations Resulting from Time-Dependent
                Releases of Chemical Substances  	     76

    EXPOSED POPULATIONS  	     83

    5.1  Identification  of Exposed Populations  	     83
    5.2  Enumeration of  the Exposed Population  	     83

         5.2.1  Enumeration of Exposed Populations via
                Simmons Market Research Bureau Reports  	     84
         5.2.2  Enumeration of Exposed Populations via
                Production and Sales Data  	     85
         5.2.3  Enumeration of Exposed Populations via
                Chemical-Specific Information 	     86

    5.3  Characterization of Exposed Population  	     86

6.   EXPOSURE ANALYSIS	     89

    6.1  Exposure Pathways and Routes  	     89

         6.1.1  Inhalation Pathways 	     89
         6.1.2  Dermal  Pathways 	     91
         6.1.3  Ingestion Pathways 	     92
         6.1.4  Other Pathways 	     94

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                        TABLE  OF  CONTENTS  (continued)

                                                                 Page No.

     6.2  Exposure Calculation 	    94

          6.2.1  Frequency of Use 	    94
          6.2.2  Inhalation Exposure 	    95
          6.2.3  Dermal Exposure 	   TOO
          6.2.4  Ingestlon Exposure 	   Ill

     6.3  Absorbed Dose 	   113

          6.3.1  Inhalation 	   113
          6.3.2  Dermal 	   113
          6.3.3  Ingestlon 	   118

 7.   REFERENCES 	   121

 APPENDIX A - Method for Estimating Inhalation Exposure to
              Partlculates Discharged  from Consumer Products ..   127    •
 APPENDIX B - Simmons Market Research  Bureau (SMRB) Reports ...   145"
 APPENDIX C - Alphabetical Listing  of  Variables Used 1n This
              Volume 	   171     >•'•• \
^APPENDIX D - Average Body Weights  of  Humans by Age Group 	   177—" „   &'
APPENDIX E - Derivation of Equations  for  Estimating                   --k-'"'•<'
              Concentrations of  Chemical  Substances In Indoor                 , -
              Air 	   179
                                     xl

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                               LIST  OF  TABLES
                                                                 Page No.
Table 1.    Consumer  Products  Found  in the Typical U.S.
            Household  	     3

Table 2.    Product Form Terminology Adopted  for Use  in This
            Report  	     8

Table 3.    Operations for  Performing a Consumer Exposure
            Assessment for  a Given Chemical  	     11

Table 4.    Sections of Volume 7 to Use in Calculating
            Inhalation Exposure  	     13

Table 5.    Sections of Volume 7 to Use in Estimating Exposure
            via Dermal Contact with and Ingestion of  Consumer
            Products  	     14

Table 6.    Summary of Physical-Chemical Properties Relevant to
            Consumer Exposure  	     16

Table 7.    Major Computerized Data Bases for Obtaining
            Physical-Chemical Properties 	     18

Table 8.    Major Published References for Obtaining  Physical-
            Chemical Properties  	     19

Table 9.    Sources of Information for Estimating Physical-
            Chemical Properties  	     22

Table 10.   Labor Production and Material Consumption Rates for
            Coatings Applied to Surfaces By Labor Category and
            Method of Application 	     27

Table 11.   Experimentally Determined Density Values for
            Select Consumer Products 	     29

Table 12.   Mass of Aerosol Product Released Per Use  	     32

Table 13.   Estimates of Overspray During Application 	     33

Table 14.   List of Functional  Components as Weight Fraction in
            Latex Wall Paint 	     38
                                  •  xii

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                         LIST  OF  TABLES  (continued)
                                                                 Page  No.
Table  15.    List  of Functional  Components  as Weight  Fraction  In
             Aerosol Furniture  Polish  	       39

Table  16.    List  of Functional  Components  as Weight  Fraction  1n
             General, All-Purpose  Liquid Cleaner  	       40

Table  17.    List  of Functional  Components  as Weight  Fraction  1n
             Motor 011  	       41

Table  18.    Weight Fractions of Functional Components - Floor
             Wax/Polish  	       43

Table  19.    Functional  Components as Weight Fraction In Vinyl
             Upholstery  Cleaners 	       44

Table  20.    Diffusion Coefficients (@ 25°C and 1 atm) for
             Selected Organic Chemicals 1n  A1r 	       59

Table  21.    Diffusion Coefficients In Aqueous Solutions at
             Infinite Dilution  	       62

Table  22.    Values for  Mixing  Factor Recommended for Several
             Common A1r  Supply  System Configurations  	       69

Table  23.    Typical Room Volumes  	       71

Table  24.   Air Changes Occurring Under Average Conditions in
             Residences  Exclusive of Air Provided for
            Ventilation 	       72

Table  25.   Summary of  Human Inhalation Rates for Men,  Women
            and Children by Activity Level 	      98

Table  26.   Film Thickness Values of Selected Liquids
            Under Various Experimental Conditions 	     103

Table  27.   Experimentally Determined Values  for Density and
            Kinematic  Viscosity of Six Selected Liquids  	     107

Table  28.   Surface Area of Body Regions  	     109
                                   xiii

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                        LIST OF TABLES (continued)
Table 29    Values of Respirable and Nonrespirable Fraction
                                                                Page No.)
Table 30.
Table 31.
Table 32.
Table 33.
of Partlculates for Selected Consumer Products ...
SMRB Reports (1983) by Volume 	
Products Listed In SMRB Reports (1983) by
Product Category 	
An Alphabetical Listing of Variables Used In
Th1 s Volume 	
Averaoe Bodv Welahts of Humans bv Aae Grouo 	
140
147
148
172
178
                                   XIV

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                              LIST OF FIGURES
                                                                Page No.
Figure 1.



Figure 2.


Figure 3.


Figure 4.


Figure 5.
Mass of Volatile Chemical Substance Remaining on
Surface of Each Square Foot of Board as a Function
of Time 	    53

Fraction Migrated as a Function of «p for Well-Mixed
Domains	    65
ICRP Model of Regional Respiratory Tract
Deposition as a Function of Particle Size
134
Total Deposition of Particulates 1n the Respiratory
Tract As a Function of Particle Size 	   135

Pulmonary Deposition of Particulates as a Function
of Particulate Size 	   136
                                    XV

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XV1

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 1.        INTRODUCTION

    This  volume  1s the  seventh  In  a  series  of  thirteen  volumes presenting
 methods for assessing exposures  to chemical  substances; the  reports are
 being developed  for  the U.S.  Environmental  Protection Agency, Office of
 Toxic Substances.  This volume  presents methods and  supporting
 Information for  estimating exposures to chemical  substances  In consumer
 products.  The methods  that are  presented 1n this  volume to  estimate
 inhalation and dermal exposure  are the basis of user-friendly, personal
 computer  programs that  comprise  the  Computerized  Consumer Exposure Models
 (CCEH).   CCEM was developed for  the  Exposure Evaluation Division of the
 Office of Toxic  Substances.   Much  of the supporting  Information included
 in this volume is also  included  in CCEM.  Such data  Include  room air
 exchange  rates,  human inhalation rates, skin surfaces areas, film
 thickness values for liquids  on  skin, mixing factors, and body weights of
 humans.   The background and purpose  of this  report,  the consumer products
 considered by this methods report, and its methodological framework, are
 discussed in the following subsections.

 1.1       Background and Purpose

    The Toxic Substances Control Act (TSCA) of 1976  (PL94-469) authorizes
 the U.S.  Environmental Protection  Agency (EPA) to assess human and
 environmental exposure to chemical substances.  An exposure assessment
 for a chemical substance attempts  to determine the amounts of that
 chemical  substance to which populations are exposed, as well as to
 identify and estimate the size of  exposed populations.  The EPA Office of
 Toxic Substances (OTS),  Exposure Evaluation Division (EED),  is
 responsible for conducting exposure assessments for  new and existing
 chemical  substances in support of  Sections 4, 5, and 6 of TSCA.

    Exposure assessments for each  of the exposure categories (i.e.,
ambient, occupational, food,  drinking water, and consumer)  have
historically been limited by a lack of complete and  reliable data.
Accurate calculation of  exposure to a chemical  substance relies  on actual
monitoring data from the media (e.g., air,  water,  food,  surfaces)
containing the chemical  and the entire time period during which exposure
occurs.   For most chemical substances,  however, these data are
 insufficient,  difficult  to obtain,  or non-existent, necessitating
estimation of exposure.   The goal  of this report is to catalog pertinent
 Information, data bases, and  tools, and to provide a systematic  approach
or methodology whereby the exposure to a given chemical  substance  in
consumer products can be estimated at any desired  level  of  detail.

 1.2      Consumer Products Considered by This Methods Report

    Consumer products are defined  in this report as products containing
chemical constituents to which human or environmental exposure may occur

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 as  a  result  of  the  use  of  the  consumer  product.  This  is a broad
 definition,  which Incorporates a multitude  of products and product groups
 and crosses  several  regulatory boundaries.

    The  product groups  that have been specifically excluded from the
 scope of  this exposure  assessment methods report are listed below.  These
 product  groups  pose  analytical complications not addressed at this time,
 are covered  by  other methods reports, or are excluded  from TSCA authority.

       Tobacco  and tobacco products.
       Non-consumer  pesticides and fertilizers.
       Business products (I.e., copying machines).
       Firearms, ammunitions, and explosives.
       Food, food products, and food additives/preservatives.
       Products containing radioactive materials.
       Products used exclusively for hobbies and crafts.
       Drugs and medical devices.

The criteria used by the FDA to distinguish between cosmetics and drugs
 state that any preparation used only for cleansing or beautification of
the skin, hair, or fingernails 1s considered a cosmetic.  Any claim of a
medicinal nature, even  if it is only implied, immediately places the
product in the drug class.  (Products such as bandages, lip balms, and
suntan lotions are Included 1n this methods report because of their
intended protective, not medicinal, purposes.)

    Finally, exposures  resulting from the use of any form of
transportation are limited to cleaning,  waxing, and polishing automobiles
and exposures to synthetic Interior materials.

    As part of the general data collection portion of this  methods
report,  a comprehensive list of consumer products found in  typical
American households was compiled and 1s  presented in Table  1.   This is
a working list that is believed to reflect those products and  product
groups of commonly used items which, through various modes  of  consumption
(exposure scenarios), lead to exposure to chemical  constituents.   This
list is  somewhat arbitrary and subjective.    Creating a finite set of
products, however, was necessary to begin the task of collecting the vast
amount of product-specific information.   Definitions of product  types,
such as  aerosol  and liquid, are cited in Table 2.

1.3    Overview of Methodological Approach

    This report presents methods  and data recommended for estimating
exposure to chemical substances in consumer products.   Methods for
estimating both "active" and "passive" exposure to chemical  substances in
consumer products are presented.   Active exposures  are  defined as

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                                                                         o
                  Table  1.   Consumer  Products  Found  in  the
                             Typical  U.S.  Household1
Consumer product category
      Consumer product
Cosmetics hygiene products
Adhesive bandages
Bath additives  (liquid)
Bath additives  (powder)
Cologne/perfume/aftershave
Contact lens solutions
Deodorant/antiperspirant  (aerosol)
Deodorant/antiperspi rant
   (wax and 1 iquid)
Depilatories
Facial makeup
Fingernail cosmetics
Hair coloring/tinting products
Hair conditioning products
Hairsprays (aerosol)
Lip products
Mouthwash/breath freshener
Sanitary napkins and pads
Shampoo
Shaving creams  (aerosols)
Skin creams (non-drug)
Skin oils (non-drug)
Soap (toilet bar)
Sunscreen/suntan products
Talc/body powder (non-drug)
Toothpaste
Waterless skin cleaners
Household furnishings
Carpeting
Draperies/curtains
Rugs (area)
Shower curtains
Vinyl upholstery, furniture

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                           Table 1.  (continued)
Consumer product category
       Consumer  product
Garment conditioning products
Anti-static  spray  (aerosol)
Leather  treatment  (liquid  and wax)
Shoe polish
Spray  starch (aerosol)
Suede  cleaner/polish  (liquid
  and  aerosol)
Textile  water-proofing  (aerosol)
Household maintenance products
Adhesive  (general)  (liquid)
Bleach  (household)  (liquid)
Bleach  (see  laundry)
Candles
Cat box litter
Charcoal briquets
Charcoal lighter fluid
Drain cleaner (liquid and powder)
Dishwasher detergent  (powder)
Dishwashing  liquid
Fabric dye (DIY)
Fabric rinse/softener (liquid)
Fabric rinse/softener (powder)
Fertilizer (garden)  (liquid)
Fertilizer (garden)  (powder)
Fire extinguishers  (aerosol)
Floor polish/wax (liquid)
Food packaging and packaged food
Furniture polish (liquid)
Furniture polish (aerosol)
General cleaner/disinfectant  (liquid)
General cleaner (powder)
General cleaner/disinfectant
  (aerosol and pump)
General spot/stain remover (liquid)
General spot/stain remover (aerosol
  and pump)
Herbicide (garden-patio) (liquid and
  aerosol)

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                           Table 1.  (continued)
Consumer product category
       Consumer  product
Household maintenance products
(continued)
 Insecticide  (home  and  garden)
   (powder)
 Insecticide  (home  and  garden)
   (aerosol and  pump)
 Insect repellent  (liquid  and
  aerosol)
 Laundry detergent/bleach  (liquid)
 Laundry detergent  (powder)
 Laundry pre-wash/soak  (powder)
 Laundry pre-wash/soak  (liquid)
 Laundry pre-wash/soak  (aerosol  and
  pump)
 Lubricant oil (liquid)
 Lubricant (aerosol)
 Matches
 Metal polish
 Oven cleaner  (aerosol)
 Pesticide (home) (solid)
 Pesticide (pet  dip)  (liquid)
 Pesticide (pet) (powder)
 Pesticide (pet) (aerosol)
 Pesticide (pet) (collar)
 Petroleum fuels (home)  (liquid  and
  aerosol)
 Rug cleaner/shampoo  (liquid and
  aerosol)
 Rug deodorizer/freshener  (powder)
 Room deodorizer (solid)
 Room deodorizer (aerosol)
 Scouring pad
 Toilet bowl  cleaner
 Toilet bowl  deodorant  (solid)
Water-treating chemicals
 (swimming pools)

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                           Table 1.  (continued)
 Consumer  product  category
       Consumer product
Home building/improvement
products  (DIY)
Adhesives,  specialty (liquid)
Ceiling  tile
Caulks/sealers/fillers
Dry wall/wall  board
Flooring (vinyl)
House Paint (interior)  (liquid)
House Paint and Stain  (exterior)
   (liquid)
Insulation  (solid)
Insulation  (foam)
Paint/varnish  removers
Paint thinner/brush  cleaners
Patching/ceiling plaster
Roofing
Refinishing products
   (polyurethane, varnishes, etc.)
Spray paints  (home)  (aerosol)
Wall paneling
Wall paper
Wall paper  glue
Automobile-related products
Antifreeze
Car polish/wax
Fuel/lubricant additives
Gasoline/diesel fuel
Interior upholstery/components,
  synthetic
Motor oil
Radiator flush/cleaner
Automotive touch-up paint
  (aerosol)
Windshield washer solvents

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                           Table 1.  (continued)
Consumer product category                  Consumer product
Personal materials                   Clothes/shoes
                                     Diapers/vinyl pants
                                     Jewelry
                                     Printed material  (colorprint,
                                       newsprint, photographs)
                                     Sheets/towels
                                     Toys (intended to be placed
                                       in mouths)
DIY = Do It Yourself.

'  A subjective listing based on consumer use profiles conducted by
  Versar.

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                    Table 2.   Product Form  Terminology Adopted
                               for Use  in This Report
    Term
           Descriptive definition
Aerosol
Pump
Liquid
Any product dispensed from a pressurized
can.  The state of the product following
delivery from the aerosol can includes
mists/aerosols, foams, liquids, and
powders.

Any liquid product dispensed from an
unpressurized container via a pumping
trigger.

Any liquid product dispensed by pouring
from its container.  This includes a
"roll-on" or similar liquid dispensing
container.
Powder
Solid
Gel/wax
Any powdered product that can be poured
or "dusted" from its container.
Powdered products include crystals and
granules.

A solid product; e.g., moth balls,
though they are crystalline in nature
and are poured from their containers,
are considered a "solid" product.

Any viscous liquid,  gel, wax,  or paste
squeezed or scooped from its container.

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exposures resulting to the user of a consumer product during active use
of the product (e.g., exposures to chemical substances 1n paints during
the act of painting).  Passive exposures pertain to exposures that occur
(1) to the user after active use has ceased, (2) to non-users who are
passively exposed as a result of user activities, and (3) to persons In
the environs of products, such as solid air fresheners, that result
exclusively 1n passive exposures.

    The methods for performing consumer exposure assessments are
discussed 1n the following five sections:

    Section 2 - Physical-Chemical Properties
    Section 3 - Product-Specific Data Required to Assess Exposure
    Section 4 - Methods for Estimating Release of Chemicals from Consumer
                Products and Concentrations of Chemicals in External Media
    Section 5 - Exposed Populations
    Section 6 - Exposure Analysis

Appendix A of this report contains methods for estimating inhalation
exposure to particulates discharged from consumer products.  Appendix B
includes guides to the individual Simmons Market Research Bureau (SMRB)
reports and to the products included in each volume, respectively.
Appendix C includes an alphabetical listing of all variables used in
Volume 7 of Methods for Assessing Exposure to Chemical Substances.   A
definition of each variable and the units in which it is expressed  are
also included in Appendix C.

    In developing the methods, a series of chemical-, product- and
environment-specific questions were addressed:
Chemical-specific:
Product-specific:
Environment-specific:
• How much of a chemical  is in the product?
• How much is permanently bound in the product
                          and unavailable for exposure?
• How is the product used,  and  for how long?
• How are chemical  constituents  released  through
  use?
• How much of the product 1s  used  and  by  whom?

• Where is the product used?
• How do ventilation,  dilution,  etc.,  affect
  available concentrations?
By answering these questions for a range of consumer products,  this
methods report attempts to supply the analytical tools necessary for
estimating exposures resulting from various typical consumer activities
and the means by which other analytical tools can be developed  to

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calculate values for more unusual consumer exposure situations.  An
effort Is made throughout the report to explain the rationale behind the
approaches followed, the derivation of all equations and models, the
assumptions and estimates used, and any Inherent limitations.

    The basic steps for performing a consumer exposure assessment for a
given chemical are to Identify the products In which It appears, Identify
appropriate exposure scenarios (detailed circumstances in which consumer
exposure occurs) for each of the products, gather the data required by
each scenario, calculate an exposure or dose based on the equation and
parameter values delineated in each scenario, and enumerate the
populations exposed (both actively and passively).  A more detailed
scheme of methodological operations is presented in Table 3.   These
method components are intentionally called operations Instead of steps to
discourage the notion that they must be fulfilled In sequential order.

    Methods for assessing exposure to chemical substances in  consumer
products are delineated in this volume for several pathways of exposure.
Sections of this volume to use in estimating inhalation exposure during
use of consumer products are presented in Table 4.  Sections  of this
volume to use in estimating dermal and Ingestion exposure during use of
consumer products are presented in Table 5.
                                    10

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             Table 3.   Operations for Performing a Consumer Exposure
                         Assessment for a Given Chemical
    Method operations
      Related data needs
Identify consumer products
  that contain chemical
Identify pertinent exposure
  routes
                         >:: -v
• Synonyms and CAS #
• Information on whether chemical will
  be a product constituent or
  residual of product processing

• Physical -chemical properties
• Basic information on product use
  patterns
• States of products before, during,
  and after use
Oevelop/select appropriate"
  exposure scenarios
Based on scenario, select
  appropriate values for key
  parameters (ranges and typical
  values)
Determine amount of chemical
  in each product
• Identification of key parameters (e.g.,
  frequency of product use,
  duration of each use, amount of
  product delivered in each use,
  inhalation rates, etc.)

• Physical -chemical properties
• Specific information on product
  use patterns
• Environmental parameters
  (e.g., room size, ventilation)

• Chemical engineering processes
  related to product formulation
• Weight percentages of constituents
  in each product
• Weight percentages of chemical in
  each constituent
                                          11

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                              Table 3.  (continued)
    Method operations
      Related data needs
Determine release of chemical
  from product

Determine concentration of
  chemical available for
  exposure

Calculate exposure
Calculate dose (optional)
• Physical-chemical properties
• Release mechanism analysis

• Input from previous three
  operations
• Input from all previous
  operations

• Exposure value
• Physical-chemical properties
• Pharmacokinetics data
Enumerate exposed populations
 (active and passive)
• Input from product identification
  and key scenario parameters
• Market data
• General population/housing
  statistics
                                          12

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                                                                                                                        c

                             Table 4.  Sections of Volume 7 to Use in Estimating Inhalation Exposure
                  Exposure pathway
                                                       Release rate of chemical
                                                       substance to air
 Concentration of
chemical substance
      in air
                                       Levels to which
                                        consumers are
                                           exposed
Inhalation of a chemical substance that is a
component of aerosols formed while spilling
or pouring a liquid or powder

Inhalation of a chemical substance during continuous
release of the contents of a pressurized aerosol
product

Inhalation of a chemical substance during
intermittent release of the contents of a
pressurized aerosol product, in which the time
between releases is on the order of a few seconds

Inhalation of a chemical substance during its
evaporation from a container of liquid or from a wet
film or coating spilled or applied instantaneously
to a surface
4.3.1
4.3.1
4.3.1
4.3.2
      4.4.2
      4.4.2
      4.4.2
      4.4.2
6.2.2
6.2.2
6.2.2
6.2.2
                                                                          H
                                                                         V/S
 Inhalation of a chemical substance during  its
 evaporation  from a wet  film or coating applied
 to  a  surface, in which  the period of application
 is  more  than a few minutes
4.3.2
      4.4.3
6.2.2
 Inhalation  of  a  chemical  substance  released  from
 a  solid that sublimes  (e.g.,  from solid  room
 deodorizer, moth balls, etc.)

 Inhalation  of  a  chemical  substance  released  from
 a  dry coating  or polymer
4.3.1
 4.3.3
      4.4.2
       4.4.2
6.2.2
 6.2.2

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               Table 5.   Sections of Volume 7  to Use in  Estimating
                        Exposure via Dermal Contact with and
                         Ingestion of Consumer Products
                                                         Estimate levels to
                                                         which consumers are
            Exposure pathway                                   exposed
Exposure to a film of liquid deposited                         6.2.3(1)
on the skin

Exposure to dusts and powders deposited on                     6.2.3(2)
the skin

Dermal exposure to chemical substances                         6.2.3(3)
contained in or adhering to solid matrices

Ingestion exposure to chemical substances                      6.2.4(1)
leached out of objects designed to be
used in the mouth

Ingestion exposure from unintentionally                        6.2.4(2)
swallowing liquids used in the mouth
                                        14

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2.        PHYSICAL-CHEMICAL  PROPERTIES

    One of the Initial efforts in any exposure assessment for a chemical
substance is identification of its physical-chemical properties.
Physical-chemical properties data are essential for a thorough
understanding or prediction of environmental fate (i.e., transport and
transformation) and the eventual environmental or exposure
concentrations.  The mechanisms of release of a chemical substance from a
consumer product, the exposure media, and the exposure route are
determined by the chemical  substance's properties.  The purpose of this
section is to (1) briefly discuss properties that are relevant to
developing exposure assessments for chemicals in consumer products and
(2) catalog information sources for obtaining experimental property data
and methods for estimating properties where such data are lacking.

2,1      General Property Information

    Table 6 summarizes the physical-chemical properties that are relevant
to performing exposure assessments for chemicals in consumer products.
Not all the properties listed are required for each chemical.  Required
properties are dictated by the physical state of the chemical and the
physical-chemical nature of the consumer product that contains it.  Many
of the properties listed may be required only when it is necessary to
estimate exposure concentrations based on chemical release algorithms.
The chemical  release algorithms are discussed in Section 4 of this
document.

2.2      Data Gathering

    The physical-chemical properties of a chemical substance can be
gathered from the scientific literature or, where experimental data are
lacking, they can be estimated.  The following subsections discuss
sources of information for experimental data and methods for estimating
physical-chemical properties.

2.2.1     Sources of Experimental  Data

    Information sources from which experimental  data can be  gathered  are
divided into  those that are computer based and accessed on-line and those
that are published documents or "hard copy."  The major on-line systems
including  address, telephone,  number, and contact for "help" information
are listed in Table 7.  Published documents that summarize and present
experimental  data are listed in Table 8.

    Prior  to  initiating any data collection, the investigator should
obtain for the chemical substance of interest the Chemical  Abstracts
                                    15

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                          Table 6.  Summary of Physical-Chemical Properties
                                    Relevant  to Consumer  Exposure
 Property/parameter
   Units
                     Comments
Molecular weight
Dimensionless        Required  input for estimation of many other
                     properties.  Required for stoichiometrically derived
                     chemical  release estimates.
Physical state
Particle size
Density
Melting point/
  boiling point
                     Solid, liquid, or gas.
                     exposure routes.
                        Assists in identification of
Length
(usually micron)
Mass/volume
(e.g., g/on3)
Degrees Celsius
Used for entrainment (dispersion) analysis of
dusts and powders and identifying area of
respiratory tract deposition.

Useful for calculating film thickness of liquids on
skin.  Indicative of whether gases (or liquids) are
heavier or lighter than air (or water).

Input for calculating vapor pressure and volatili-
zation rates.  Identifies physical state of
substance at ambient conditions.
Vapor pressure
Henry's law constant
mm Hg; torr;
atmospheres
Heat of vaporization     Calories/mole
Dimensionless
or atm-m^/mol
Essential for predicting the behavior and fate of
chemicals in the environment:  rates of evaporation,
equilibrium air concentrations (worst case).

Quantity of heat required to convert a unit mass of
liquid into a vapor without a rise in temperature.
Required input for estimating other properties such
as vapor pressure.

Indicative of a chemical's propensity to volatilize
from water.   Required input for calculating
volatilization rates.
Solubility
Mass/volume
Maximum amount of the chemical that will  dissolve in
pure liquid at a specified temperature.   Facilitates
calculation of worst case concentrations.  Required
input for calculating volatilization rates of
chemicals from solutions.
                                                  16

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                                        Table 6.  (continued)
 Property/parameter
   Units
                     Comments
Diffusion  coefficients
   (i.e., air, water,
   solids)
Octanol /water
  partitioning
  coefficient
Volatilization rates
Lengths/time         Indicative of a chemical's ability to move in a
(e.g., cm2/s)        liquid, gas, or solid based on inter-molecular
                     collisions (not turbulence or bulk transport).
                     Diffusion coefficients through gas range from 10"
                     to 10~2 cm^/s; through liquids from 1(H> to
                     10-6 crn^/s; and through solids from 10~7 to
                     10-20 cn£/s.  Required input for calculating
                     volatilization rates and migration through solid
                     matri ces.
Dimensionless
Length/time
(e.g., cm/hr)
Activity coefficient     Dimensionless
Ratio of a chemical's concentration in the octanol
phase to its concentration in the aqueous (water)
phase.  Important indicator of a chemical's fate.

Required for estimating air concentrations of
chemicals evaporating from liquids and solids.

A factor for compensating for non-ideal behavior of
compounds in solution.  Required input for
estimating properties of mixtures.
                                                 17

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                                      Table  7.  Major Computerized Data Bases for Obtaining Physical-Chemical Properties
         Data  base  name
  Sponsor/contract support
Help information
Garments
    Chemical  Information System
      (CIS)
    HAZARDLINE
oo
    Medical Literature Analysis
      and Retrieval System
      (MEDLARS)
    Chemicals in Commerce
      Information System (CICIS)
NIH/EPA                                Mike Keller
Computer Science Corp.                 703-237-1333
P. 0. Box 2227                         800-368-3432
Falls Church, VA 22042

Physicians World Communication Group   Kay Sloves
Occupational Health Services, Inc.     800-223-8978
400 Plaza Drive
Secaucus, NO 07094
National Institutes of Health          301-496-6193
National Library of Medicine           800-638-8480
MEDLARS Management Section
8600 Rockville Pike
Bethesda, MD 20014

USEPA OTS/MSD-SDB                      Geri Nowak
Office of Toxic Substances             202-382-3568
Management Support Division
Washington, DC  20460
                      Access to a wealth of computerized information including
                      structure and nomenclature, chemical evaluation, clinical
                      toxicology, registry of toxic effects, and oil and hazardous
                      materials technical assistance data.

                      Access to environmental and occupational information on
                      hazardous substances including physical and chemical
                      properties, personal protective equipment, and medical
                      surveillance to test requirements, waste disposal and
                      leaks, spills, and fire fighting information.

                      On-line chemical dictionary access  (CHEMLINE) and a wealth
                      of information on toxicology and bibliographic data on
                      chemical substances.
                      1977 TSCA Inventory of Chemical Substances.  Chemical
                      properties, structures, production, and use.
                      Note: Data base has not been updated since  1977 and  is
                      therefore somewhat out-of-date.

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                   Table 8.  Major Published References for Obtaining
                              Physical-Chemical Properties
        Document
              Comment
CRC Handbook of Chemistry and  Physics
Chemical Engineers Handbook
Lange's Handbook of Chemistry
The Merck Index
Kirk-Othmer Encyclopedia of Chemical
  Technology

Farm Chemicals Handbook
Handbook of Environmental Data on Organic
  Chemi cals
Good source  for general properties of
a  large variety of chemicals.

Good source  for general properties of
a  large variety of chemicals.

Good source  for general properties of
a  large variety of chemicals.

Good source  for pharmaceutical or
medicinal chemical properties.

Good source  for general properties
of a large variety of chemicals.

Good source  for properties of farm
chemicals, particularly pesticides.

Good source  for properties of organic
chemicals.
Physical Properties of Chemical Compounds
  (Volumes I, II, III)

Physical Properties of Hydrocarbons
  (Volumes I and II)
Cyclic, acyclic, and aliphatic
compounds.

Paraffinic, halogenated, and oxyge-
nated hydrocarbons (alcohols, oxides,
glycols) (Volume I); organic acids
ketones, aldehydes, ethers, esters
nitrogen compounds, aromatics, cyclic
hydrocarbons, and sulfur compounds
(Volume II).
The Aldrich Catalog - Handbook of Organic
and Biological Chemicals

Vapor Pressure of Organic Compounds
General properties of many organic
chemicals of environmental interest.

Good source for experimental  vapor
pressure data.
                                           19

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                                  Table 8.   (continued)
       Document
             Comment
Technical Data Book - Petroleum Refining
   (Volumes I and II)

Handbook of Vapor Pressures and Heats of
  Vaporization of Hydrocarbons and
  Related Compounds

The Properties of Gases and Liquids

Faith, Keyes, and Clark, Industrial
  Chemicals
Basic properties of organic compounds
that are petroleum derived.

Vapor pressure of hydrocarbons.
Covers most general properties.

General properties for a small number
of chemicals.
Publications of the National Bureau of
  Standards (NBS); National Standard Data
  Reference System (NSRDS)
     - Journal of Physical and Chemical
       Reference Data
     - NSRDS - NBS publication series
     - Miscellaneous technical society
       publications

Publications of the Engineering Sciences
  Data Units,  Ltd.  For example:
    - Viscosity of liquid aliphatic
        hydrocarbons: alkanes
    - Thermal  conductivity of liquid
        carboxylic acids
    - Heat capacity and enthalpy of
        liquids: aliphatic alcohols
    -  Vapor pressures and critical points
         of liquids.   XIV: aliphatic oxygen-
         nitrogen compounds
See Appendix A of Handbook of Chemical
Property Estimation Methods.  Environ-
mental Behavior of Organic Chemicals
for additional information.  NSRDS is
a good source for industrial process
data including information on thermo-
dynamic, transport, and physical
properties of industrial chemicals.

Information on ESDU and publications
can be obtained from:
    ESDU
    251-259 Regent Street
    London WIR 7AD
    England
                                           20

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Service  (CAS) number and synonyms for the name of the chemical
substance.  Most current on-Hne data bases and published documents
catalog  chemical data according to CAS number.  This minimizes confusion
Inherent 1n storing and retrieving chemical data according to chemical
name since most chemicals have more than one name.  The CAS number for a
chemical substance can be obtained from:

    Toxic Substances Control Act Chemical Substances Inventory
    Volumes I-IV (Initial Inventory, Cumulative Supplement, User
    Guide and Indices to the Initial Inventory, and Trademarks and
    Product Names)
    U.S. Environmental Protection Agency
    Office of Toxic Substances (TS-799)
    Washington, DC  20460

Chemical name synonyms are particularly Important because consumer
product manufacturers frequently 11st consumer product chemical
formulations according to trade or generic chemical names.  For example,
specific solvents 1n paints may simply be listed as "cellosolves" or
"glycols."  A 11st of specific chemical names and generic names Is
extremely useful for securing physical-chemical property data and other
chemical use data related to consumer products.  Many of the on-line data
bases and published documents found 1n Tables 7 and 8 include chemical
name synonyms.

2.2.2    Methods for Estimating Physical-Chemical Properties

    Methods for estimating physical-chemical properties can also be found
1n on-line computerized data bases and 1n the published literature.  The
on-line methods are those contained in EPA-OTS's  Graphical Exposure
Modeling System (GEMS).  Information on GEMS and inclusive data bases can
be obtained from GSC (1983) or by contacting the

         Modeling Section
         U.S. Environmental Protection Agency
         Office of Toxic Substances (TS-798)
         Washington, D.C.  20460
         (202) 382-2256

Table 9 lists the chemical  property estimation systems  and methods
Included in GEMS, as well as published documents that contain additional
methods for estimating physical-chemical  properties.

2.3      Summary

    The functional steps in securing physical-chemical  properties for a
chemical substance are summarized as follows:
                                    21

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                   Table  9.   Sources  of  Information  for  Estimating
                              Physical-Chemical  Properties
        Source/methods
          Comment
Computerized  systems

•  Graphical  Exposure Modeling System  (GEMS)
         USEPA
         Office of Toxic Substances
         Chemical Fate Modeling Team
         Washington, D.C.  20460
         (202) 382-2256

   (1)  CHEMEST
         - Solubility in water
         - Soil absorption coefficient
         - Bioconcentration factors for fish
         - Activity coefficients
         - Boiling point
         - Vapor pressure
         - Rate of volatilization from water
         - Henry's law constant

   (2)  Molecular Structure File (S File)

   (3)  CLOGP  (Log Kow - octanol/water
         partition coefficient)

Published documents*

   (1)  Handbook of Chemical Property Estimation
       Methods - Environmental Behavior of
       Organic Compounds
         - Octanol/water partition coefficient
         - Solubility in water
         - Solubility in various solvents
         - Adsorption coefficient for soils
           and sediments
         - Bioconcentration factor in aquatic
           organisms
         - Acid dissociation constant
GEMS User's Guide.
CHEMEST User's Guide
(CHEMEST is a computerized
version of the procedures
listed below in Handbook of
Chemical Property Estimation
Methods - Environmental
Behavior of Organic
Compounds.)
SPILES User's Guide.

CLOGP User's Guide.
Not reconmended for fate
of chemicals via hydrolysis
and photolysis.  See
documents listed below.
                                           22

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                                Table 9.  (continued)
        Source/methods                                             Comment
          - Rate of hydrolysis
          - Rate of aqueous photolysis
          - Rate of biodegradation
          - Atmospheric residence time
          - Activity coefficient
          - Boiling point
          - Heat of vaporization
          - Vapor pressure
          - Volatilization from water
          - Volatilization from soil
          - Diffusion coefficients in air and water
          - Flash points of pure substances
          - Densities of vapors, liquids, and solids
          - Surface tension
          - Interfacial tension with water
          - Liquid viscosity
          - Heat capacity
          - Thermal conductivity
          - Dipole moment
          - Index of refraction

  (2)  Structure Activity Correlations for
       Environmental Reactions
          - Rate of hydrolysis
          - Rate of photolysis
          - Rate of oxidation
          - Rate of volatilization
          - Absorption to sediment and soils

  (3)  Validation of Estimation Techniques for           Supplemental data and
       Predicting Environmental Transformation           update of Structure
       of Chemicals                                      Activity Correlations
          - Oxidation in water                            for Environmental
          - Oxidation in air                              Reactions.
          - Rate of hydrolysis
          - Metal  complexation
*Note:  Documents listed are those principally used by EPA-OTS.  The scientific
        literature, much of it referenced in the above documents, includes a wealth
        of background information and methods for estimating physical-chemical
        properties.
                                           23

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1.  Obtain CAS number and compile list of chemical synonyms.
    Tables 7 and 8 list information sources for obtaining CAS numbers
    and synonyms.

2.  Retrieve or gather experimental data for physical-chemical
    properties of interest from on-line systems or published
    documents.  Table 7 lists computerized systems, and Table 8
    cites published documents from which physical-chemical property
    data can be obtained.

3.  Where experimental data are lacking, estimate required properties
    according to appropriate methods.  Methods and systems for
    estimating physical-chemical properties are listed in Table 9.

4.  Summarize all data in tabular format, and clearly indicate all
    units of measurement and sources of information including methods
    used to estimate properties where experimental data were lacking.

Note:   For each physical-chemical property of interest, all
       immediately available data should be gathered.  It is possible
       that different isomers of a chemical substance may have vastly
       differing property values.  Property data-may also vary
       because values were derived under different laboratory
       conditions or controls; errors in experimental data are also
       not uncommon.   All property values gathered from the
       experimental literature should be carefully reviewed  and any
       inconsistencies noted.  Estimation techniques can be  used to
       help verify or resolve inconsistencies in experimental data.
                                24

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3.       PRODUCT-SPECIFIC DATA REQUIRED TO ASSESS EXPOSURE

    Prior to estimating the concentration of a chemical substance in an
external medium, the assessor should estimate the quantity of the
chemical released during use.  In general, release of a chemical
substance to air from a consumer product can occur by three mechanisms:

    1.  Direct application to a surface, including skin.

    2.  Release of a chemical substance from pressurized aerosol products
        and poured products that aerosolize releasing mists or
        particulates.

    3.  Migration through the solid matrix of a consumer product and
        subsequent volatilization or leaching.

    The following sections discuss factors required to estimate the
amount of a chemical substance that can be released from a consumer
product during an exposure period.  Methods for estimating the values of
these factors for specific products are also presented in the sections
that follow.  Section 3.1 presents data for products that are applied as
liquid films, while Section 3.2 contains data for aerosol products.
Section 3.3 discusses sources that can be used to determine the presence
and the amounts of specific chemicals in consumer products.  A generic
approach for determining weight fractions of specific chemicals in
consumer products is also presented in Section 3.3.

3.1     Amount of Chemical Substance Applied Directly to Surfaces

    The amount of a chemical  substance that is applied to a surface  can
readily be estimated from the following product-specific data.

    1.  Surface area to which the consumer product is applied.

    2.  Surface area that a given amount of the consumer product can
        cover (material consumption rate).

    3.  Density of the consumer product.

    4.  Weight fraction of the chemical substance in the product.

    5.  Surface area that can be covered by the consumer product in  a
        given amount of time  (labor production rate).
                                    25

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    Sources of Information concerning material consumption rates Include
product labels and the Estimating Guide - 1982 published by the Painting
and Decorating Contractors of America (PDCA 1982).  Material consumption
rates for a number of generic types of products are also reported In PDCA
(1982) and are differentiated according to: (1) method of application
(e.g., brush, roller); (2) type of surface to which the generic product
1s being applied (e.g., plywood, smooth siding, smooth finish plaster,
sandflnlsh plaster, concrete); (3) which coat 1s being applied (e.g.,
primer, first coat, second coat, third coat); and (4) type of sheen of
the product (e.g., flat finish, semi-gloss, gloss).  Table 10 presents
material consumption rates 1n units of square feet per gallon for a
number of labor categories as reported In PDCA (1982).  Table 11 presents
values for densities of selected products 1n units of grams per cubic
centimeter (g/cm-3) based on actual laboratory measurements of specific
name-brand products (Versar 1984c).  Material consumption rates and
densities reported for generic types of products presumably differ very
little from material consumption rates and densities for specific
name-brand products within a given product group.  Values for material
consumption rates and densities for specific brands can be used In place
of values for generic product types where generic product values are not
readily available.  The converse situation also applies.

    The following example Illustrates how surface area covered, material
consumption rate, product density, and weight fraction of a chemical
substance in a product can be used to determine the mass of a chemical
substance applied to a surface.

        A table with surface area of 27 square feet Is covered with one
        coat of varnish.   Assuming a chemical substance comprises 5
        percent by weight of the varnish, what mass of chemical substance
        1s applied to the surface?

        Divide the surface area covered by the material consumption rate
        reported 1n Table 10 to obtain the number of gallons of varnish
        required to cover the surface of the table,

                   27 ft2/600 ft2/gallon = .045 gallons

        Multiply the number of gallons determined In Step 1  by the
        density of varnish reported In Table 11  and by the factor for the
        number of cm3 per gallon to obtain the number of grams of
        product applied to the surface.

          0.45 gallons x  .879g/cm3 x 3785 cm3/gallon = 150 grams
                                    26

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          Table  10.   Labor Production and Material Consumption Rates for Coatings
                     Applied to Surfaces by Labor Category and Method of Application
Labor category
Paint doors


Paint picture
mouldings, chair rails,
window frames, and other
trim up to 6-inch width
Paint windows
(no frame)
Stain
Shellac
Varnish
Lacquer
interior trim
Method of
application
Brush
Roller
Spray
Brush



Brush

Brush
Brush
Brush
Spray

Labor production
rate (ft2/hr)
125
275
400
200



150

220
200
175
250

Material consumption
rate (ft2/gallon)
400
400
300
1,000



450

500
600
600
275

Lacquer
interior doors and
cabi nets
Spray
275
                                                                         250
Lacquer
interior panelling

Remove varnish with
liquid remover from a
flat surface

Remove paint with
liquid remover from a
flat surface

Wax and polish floors
Spray
                                                450
                     45
                     30
                    200
                                             250
                         180
                         175
                       1,080
                                               27

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                                   Table  10.   (continued)
  Labor category
Method of
application
Labor production
rate (ft2/hr)
Material consumption
rate (ft2/gallon)
Apply floor seal
to maple and pine

Apply floor seal to oak

Flat finish paint on        Roller
plywood in a new residence
Flat finish paint on
smooth siding in a new
residence
Roller
    400


    450

    350


    325
        500


        500

        300


        300
Flat finish paint on
smooth finish plaster in
a new residence
Gloss/semi -gloss paint
on smooth finish plaster
in a new residence
Gloss/ semi -gloss paint
on sandfinish plaster
in a new residence
Latex flat finish paint
on smooth finish plaster
in a new residence
Latex flat finish paint
on rough finish plaster
in a new residence
Brush
Roller
Spray
Brush
Roller
Spray
Brush
Roller
Spray
Brush
Roller
Spray
Brush
Roller
Spray
245
325
500
260
350
550
150
275
400
225
340
475
175
265
475
500
475
550
500
475
550
295
280
320
400
380
440
300
285
325
Source:  PDCA (1982).
                                               28

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          Table  11.   Experimentally  Determined  Density  Values  for
                     Selected  Consumer  Products
          Product                    .                Density*  (g/cm^)

Hinwax wood  stain                                         0.800
Semi-gloss interior  latex paint                           1.168
Marine spar  varnish                                       0.879
Polyurethane clear satin finish                           0.866
Varathane plastic gloss paint                             1.084
Anti-rust oil-based  enamel paint                          0.884
Furniture polish-lemon oil                                0.834
Pure shellac                                             0.896
Gloss black  enamel paint                                  0.903
Latex flat wall paint                                     1.240
Floor shine  cleaner/wax                                   1.017
Fiberglass resin                                          1.106
Car wax finish restorer                                   1.017
Antique oil  finish                                        0.832
High gloss car wax                                        1.022
Redwood latex stain                                       1.332
Carpenters wood glue                                      1.084
Floor deck enamel paint                                   1.067
Interior  acrylic latex wall and trim paint                1.233
White interior ceiling paint                              1.182
* At room temperature (~25°C).
Source:  Versar (1984c).
                                    29

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         Multiply  the  weight  fraction  of  chemical  substance  1n the product
         by  the  number of  grams  of  product  estimated to be applied to the
         surface of  the table (from step  2)  to derive the mass of chemical
         substance applied to the surface of the table.

                        150 grams x .05   =7.5 grams

     To  assess the amount  of  a chemical substance  to which an Individual
may  be  exposed  requires knowledge  of  the amount of a chemical substance
that may  potentially  enter an external medium from liquids  or films
applied  to  a surface  and  of  the duration of application of  the product.
The  period  of application can be readily estimated from information
regarding the rate  at which  a specific product Is applied to a surface.
This rate,  often  referred to as the labor  production rate,  is reported
for  a number of labor categories in PDCA (1982).  Labor production rates
obtained  from PDCA  are presented in Table  10.  Like the material
consumption rates shown in this table, the  labor  production rates are
also differentiated according to method  of application, type of surface
to which  the generic  product is being applied, which coat is being
applied,  and type of  sheen of the  product.  Data  regarding  the time for
application of  a  product  is  not only  useful for estimating  the period of
active exposure,  but  is also useful in Itself as  an Input for an
algorithm that  predicts room air concentrations of a chemical substance
under conditions  1n which the release of the chemical  is time-dependent
(see Section 4.4.3.).

    The following example illustrates how the surface  area covered and
the  labor production  rate can be used to estimate the  duration of
application of a  consumer product  in the form of a liquid or film applied
to a surface.

    The walls of a  room 8 feet high, 8 feet wide,  and  11  feet long (304
    square feet) are  covered with  one coat of a flat finish paint using a
    roller.   Assuming  the walls are of smooth siding,  how long does  it
    take to apply the  first  coat?

    Divide the value  for  the surface area of the walls  of the room by the
    labor production  rate value from Table 10 reported  for the first  coat
    of flat finish paint applied to smooth siding  with  a  roller  to obtain
    the value for duration of application.

                          304 ft2   =  .94 hours
                       325 ft2/hr

This duration accounts only for roller application.   It excludes brush
painting of corners, moulding, and trim.
                                    30

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 3.2       Amount  of  a  Chemical  Substance  Released  by  Use  of  Aerosol and
          Pump  Spray Products and  by  Pouring  or  Spilling  Liquids and
          Powders

     Estimation of the  amount of a  chemical substance released  from
 consumer  products that generate aerosols  requires  knowledge  of the weight
 fraction  of  chemical  substance in  the  consumer  product,  the  mass of
 product released during the period of  active use  or  active  discharge, and
 the  fraction of  product that does  not  contact its  intended  target.
 Guidelines for determining the weight  fraction  of  chemical  substance in a
 consumer  product are  presented in  Section 3.4.  Data on  the  mass of
 product released during the period of  actual discharge are  needed for
 scenarios in which  products are discharged for  only  a few seconds
 (instantaneously) during each exposure event.   Data  on the mass of
 product released during the period of  active use,  however, are needed for
 scenarios in which  products are discharged for  more  than a  few seconds
 and  for scenarios consisting of more than one active discharge, provided
 each discharge occurs  within short intervals of the  other (e.g., on the
 order of  seconds).

     Table 12 presents  estimated ranges of values  for-mass of product
 released  per use based on responses received from  roughly 40 households
 as part of an informal survey (Cote et al. 1974).  The values shown in
 Table 12 were derived  from information provided on rate and  frequency of
 use  by survey respondents.  Rates of use were estimated from the numbers
 and  sizes of containers which the respondents reported using over a given
 period of time.  Cote  et al. (1974) note that they have less confidence
 in the value reported  for oven cleaner than for other products because
 oven cleaner is used infrequently and, therefore, the raw data used to
 derive these estimates were not as plentiful.

    Aerosol that does  not contact its intended  target is referred to as
 overspray.  The amount of overspray that occurs during application is a
 function of the pressure exerted on the contents of  the container and the
 size of the orifice through which the contents are discharged, the size
and shape of the target, and the size of the particles composing the
 spray.  No specific information on values for overspray for aerosol
consumer products has  been found.   Estimates of paint loss,  or overspray,
during application,  however, are available for several methods of
application (Gross  1970).   These estimates are presented in Table 13.
Conventional  air spray systems  atomize the paint fluid by intersecting
jets of compressed air (Gross 1970).   Airless or hydraulic spray systems
atomize paint by the sudden release of high pressure as the fluid is
ejected through a small orifice (Gross 1970).  Electrostatic spray
systems atomize fluids through  the application of high voltage static
electricity as the paint flows  off a  sharp edge or point (Gross 1970).
                                  .  31

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            Table 12.   Mass of Aerosol  Product Released Per Use








Aerosol product                                     Mass (grams/use)






Deodorant spray                                       2.5 - 3.0




Hair spray                                            7.0 - 9.3




Shaving foam                                          3.0 - 4.0




Air freshener                                         7.0 - 14.0




Disinfectant                                             9.4




Furniture polish                                        14.0




Dust spray                                            7.0 - 14.0




Oven cleaner                                          200 - 250








Source:  Cote et al. (1974).
                                    32

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           Table 13.  Estimates of Overspray During Application








Method of application                               Overspray fraction






Conventional air spraying                             .20 - .40




Airless spraying                                      .10 - .20




Electrostatic spraying                                .05 - .15








Source: Gross (1970).
                                   33

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     Aerosol  products  used  by  consumers are discharged in a manner similar
 to airless  spray  systems.   For  reasonable worst case estimates of
 exposure  to  aerosol consumer  products that are surface sprays
 (e.g.,  spray paints), a value of 0.40 for fraction of overspray is
 suggested.   A value of 1.0  for  fraction of overspray is suggested for
 aerosol consumer  products  that  are  space sprays (e.g., air fresheners).
 Additional  effort  is  needed to  obtain values for overspray fractions of
 aerosol consumer  products.

     A  recent study on aerosols  formed during free-fall of liquids and
 powders in  static  air (Sutter et al. 1982) reported that an average
 weight  fraction of 0.00003  of a "spilled" liquid and 0.00019 of a
 "spilled" powder  can  be expected to become airborne in static air when
 spilled from a height of one meter  onto the floor of a room-sized
 enclosure (Versar  1985).  The mass  of chemical substance unintentionally
 released  to  air from  accidental spills of liquids and powders can be
 estimated by  multiplying the value  for fraction of material entrained in
 air  by  the total mass of powder or  liquid spilled and by the weight
 fraction  of  chemical  substance  1n the spilled product.

 3.3     Identification of Consumer Products and Formulations

     A key step in assessing consumer exposure is to identify the products
 containing the chemical of  interest.  Identification of the consumer
 products  in  which a particular  chemical substance will appear directs the
 exposure  analyst to the appropriate exposure routes and relevant generic
 scenarios necessary to calculate consumer exposure.

     A chemical may appear in a consumer product as an ingredient or as a
 residual  (Impurity) of the product manufacturing process.   Most of the
 information  sources presented in this section deal only with those
 chemicals intentionally incorporated as an ingredient.  Chemicals that
 occur as  impurities in consumer products are not as easily identified
 through conventional sources; identification of such consumer products
will  rely heavily on process engineering estimates and qualitative
 estimates from knowledgeable contacts in the subject industries.

     The information sources found most useful for identifying pertinent
 consumer products are listed below.

     •  Clinical Toxicology of Commercial Products (CTCP)

     •  Consumer Product Safety Commission (CPSC)  - economic analysis

     •  Organic Chemical  Producers Data Base (USEPA)
                                    34

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     •   Literature:

        -  The Merck  Index
        -  The Condensed Chemical Dictionary
        -  K1rk-0thmer  Encyclopedia of Chemical Technology. 3rd edition.
        -  The weekly Chemical Marketing Reporter

     Once  the consumer products are Identified, the typical amount of
chemical  found  in each product 1s determined.  This formulation
Information satisfies the weight percent (WF) parameter used In the
exposure  calculation  (discussed 1n Section 6).  The Information sources
found most useful 1n determining product formulations are:

     •   Clinical Toxicology of Commercial Products (CTCP)

     •   Consumer Product Safety Commission (CPSC) - CHIP Data Base

     •   The Chemical Formulary (Chemical Publishing Co.)

     •   Independent Investigation:

        -  Related patent literature
        -  Industry and trade association contact
        -  Spot surveys of products currently on shelf
        -  Literature (product- or brand-specific)

     Clinical Toxicology of Commercial Products. 4th edition,  (Gosselln
et al.  (1984) Williams and Wllklns Co., Baltimore, MD), Is by far the
most useful resource with regard to product coverage and detail  of
product formulations.  CTCP 1s kept up-to-date on a computerized format
(available to Chemical Information System,  CIS-USEPA,  subscribers) and
has  the advantage of allowing search by chemical constituent, product
name, product use, manufacturer, and other  criteria.

     The Chemical Formulary, by H.  Bennett (Chemical  Publishing Co.,  Inc.,
NY), 1s a valuable complement to CTCP 1n the determination of
formulations for a variety of consumer products.  The  23 volumes of  The
Chemical  Formulary (from 1933 to 1981)  represent a vast collection of
commercial formulas, which Include exact amounts and  percentages of
constituent chemicals and notes on preparative techniques.  Complete or
partial sets of volumes are available 1n select professional  and public
libraries 1n the Washington,  D.C., area.

     The Economics Division of the Consumer  Product Safety Commission
Investigates the occurrence of selected chemicals In  consumer products.
In Its evaluations,  CPSC uses many of the same tools  mentioned above;
                                    35

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however,  1t also  Identifies consumer products and their formulations
through economic  analyses and CPSC's CHIP data base.  The CHIP data base
Is an 1n-house, on-Hne system developed from various resources collected
by CPSC.  Some of CHIP'S components are:  (1) CTCP (discussed above);
(2) elements from the NIOSH trade name Ingredient data base, which
contains  formulations of Industrial, commercial, and consumer products.
(This data base 1s being updated; estimated availability 1s September
1985.)  Existing  data are limited and largely out-of-date.  Contact Is
Mr. David Sundln, NIOSH, Cincinnati, Ohio, 513-684-4491); (3) some
occupational chemical exposure data (of unknown origin); (4) formulation
data for  some drugs and cosmetics collected from the FDA; and
(5) consumer product formulation data compiled Independently by a CPSC
contractor (Auerbach) 1n 1975.  After CPSC makes their evaluation for a
particular chemical substance (based on Its economic analysis, CHIP
results,  and Independent field Investigation), the results are kept on
file.  These files (by chemical) can provide Information and data found
nowhere else 1n the literature and are considered a primary resource to
this phase of the exposure assessment.  Non-proprietary portions of the
file for  a particular chemical can be retrieved through a freedom of
Information request to:

                    The Freedom of Information Officer
                          Office  of  the  Secretary
                    Consumer Product Safety Commission
                          Washington,  DC   20207

    The remainder of the sources for product identification and
formulation are more commonly available data or reference tools that do
not provide consumer product or formulation Information as their primary
function.   Such resources are generally used to identify consumer
products  that may contain the chemical in question.   The presence of the
chemical may be verified through other resources (usually manufacturers,
trade associations, or laboratory analysis).

    The availability of information regarding the weight fraction of a
specific  chemical in a consumer product varies with  the chemical  and the
consumer  product, and can also be a function of the  time and resources
available to the assessor.  In some Instances, time  and resources will
not allow an assessor to thoroughly investigate the  sources useful in
determining formulations for products identified as  containing the
chemical  of interest.  In such cases, a generic approach to determining
weight fractions of chemical substances in consumer  products is
suggested.  The first step of the generic approach is  for the assessor to
ascertain the function of the chemical substance in  the consumer  product
for which weight fraction information is being sought.   Once the  function
is known,  the assessor can refer to readily available  resources for
information regarding the weight fraction of the functional component in
                                    36

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the consumer product.  An unpublished source of Information that Includes
this type of data 1s Standard Scenarios for Estimating Exposure to
Chemical Substances During Use of Consumer Products (Versar 1986).
Tables 14 through 19 present data on weight fractions of general
components of six selected consumer products as presented in Versar
(1986).
                                    37

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                     Table  14.   List of Functional Components as Weight
                              Fraction in  Latex Wall Paint
    Functional component
Weight fraction
in product
        Examples
    Binder
    Thinner
                  Vehicle
    Pigment

    Extender pigment/
      inert filler

    Coalescing solvent
    Plasticizer

    Freeze-thaw stabilizer


    Surfactant

    Defoamer
    Dispersing/Emulsifying
      agent

    Preservative
.10-.25



.25-.60
  0-.10

.10-.20

.20-.55


.002-.02a


    0-.0033

    0-.02b


.0004-.002a

.002-.005a


.005-.012a


.0002-.0025a
Polyvinyl acetate, acrylic,
and/or styrene butadiene
elastomers

Water
Vegetable oil; resin

Titanium dioxide

Calcium carbonate;
alumino silicate

Ethers or ether esters of
ethylene or propylene glycol

Adi pates; phthalate esters

Ethylene and/or propylene
glycol

Sulfosuccinates

Aliphatic hydrocarbons and
fatty acid ester mixtures

Carboxylic acid salts;
trialkyltin fluoride

SuIfones; mercury
    compounds
aThe range of values for weight fraction for this functional component were derived
 from information on formulas reported for latex flat wall paint in JRB (1982).
^According to Gosselin (1984), latex wall paint can contain up to 2 percent ethylene
 glycol; the specific function(s) of ethylene glycol in latex wall  paint was not,
 however, reported.  Schurr (1981) reports that ethylene and propylene glycols are used
 as freeze-thaw stabilizers and as slow-evaporating solvents.  The range reported here
 is based on the assumption that ethylene glycol is functioning only as a freeze-thaw
 stabilizer.

Sources:  Flick (1982)
          Gosselin et al.  (1984)
          JRB (1982a)
          JRB (1983a)
          Schurr (1981).                       33

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              Table 15.  List of Functional Components as Weight
                       Fraction  in Aerosol  Furniture Polish
 Functional
 components
  Weight
 fraction
      Examples
Film-forming
ingredients

Film-forming
ingredients

Film-forming
ingredients

Emulsifiers

Sol vent
Odor-Formi ng
ingredients

Preservative

Propellants
  - Compressed gas
  - Compressed liquid

Carrier

Refractive index
modifier
0 -  .05


0 -  .04


0 -  .02


.01  - .03

0.0  - .30




.0005 - .003


.0005 - .002


.01 - .02
.04 - .15

.40 - .90

0 -  .05
Natural/synthetic waxes
Silicone oils
Mineral oils
Surfactants

Petroleum or synthetic
napthas, aliphatic
hydrocarbons

Essential oils, perfumes
Fungicides, bacteriocides
Nitrous oxide
Hydrocarbons

Water

Natural/synthetic waxes,
resins
Sources:  Gosselin (1984)
          ORB (1983b)
          Randall and Dwyer (1982).
                                        39

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        Table 16.  List of Functional Components as Weight Fraction
                   in  All-Purpose  Liquid Cleaner*
     Functional  component
Weight fraction
  in product
Examples
Carrier                           Up to  .96

Cleaning agent  (includes
  surfactants,  detergents,
  foamants)                       .03 -  .32
Builder**                       Trace - .33

Abrasive                           .10 - .15

Dispersing agents                  .01 - .24


Emulsifying agents                 .01 - .04


Wetting agent                      .01 - .04


Ammonia                            .01

Opacifier                          .01

Fragrance                          .01

Color agent                     Trace - .01

Disinfectant/deodorizer            .01 - .07

Stabi1i zer                      Trace

Water softener                        ?
                       Water
                       Sodium carbonates,
                       alkyl  sulfates

                       Complex phosphates

                       Calcium carbonate

                       Quaternary ammonium
                       compounds

                       Sulfated fats and
                       oils

                       Dialkyl
                       sulfosuccinates
                       Pine  oil
                      Anti-streaking
                      agent,  film  reducer
Sources:  USEPA (1984); JRB (1982b)

*  Best characterized by its use on indoor household surfaces (e.g.
   countertops, floors, appliances).

** Upgrades cleaning efficiency of surfactants (JRB 1982a).
                                   40

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                Table 17.  List of Functional Components as
                          Weight  Fraction in Motor Oil
    Functional
    components
   Weight
  fraction
          Examples
Petroleum  lubricating     0.75  -  1.00
 oil or basestock
Oi spersant
Detergent
Oxidation/corrosion
 inhibitor
Anti-rust agent
Viscosity index
 improver
Anti-foam agents
0.03 - 0.05A
0.025 - 0.05A
 0.01 - 0.02A
  0-0.10
 0.02 - 0.20*
 0 - trace'
                                   ,B
Pour-point depressants     0 - 0.05
Paraffinic, aromatic, and/or
alicyclic  (naphthenic)
components

Polymeric succinimides;
olefin^Sg reaction
products; polyesters;
benzylamides

Barium sulfonate; calcium
sulfonate; magnesium sulfonate;
barium phenate; calcium
phenate; phenol sulfides;
barium phosphonates

Zinc dithiophosphates; barium
dithiophosphates; calcium
dithiophosphates

Amine succinates; aklaline
earth sulfonates

Methacrylate polymers;
aerylate polymers; olefin
polymers and copolymers;
styrene-butadiene copolymers;
pol y i sobuty 1 enes;
poly-alky1styrenes

Silicone polymers

Alkylarcmatic polymers;
polymethacry1ates
                                   41

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                          Table  17.   (Continued)
   Functional
   components
 Weight
fraction
          Examples
Extreme-pressure agents    0 - 0.01
Anti-wear additives
0 - 0.01
Compounds containing sulfur,
chlorine, or phosphorous alone
or in combination

Fatty acids; esters; ketones;
organic chlorine compounds;
organic sulfur compounds;
organic phosphorus compounds;
organic lead compounds
Sources:  Booser (1981)
          Wills (1980)
          Gosselin et al. (1984).

ADave Pavlich, Lubrizol Corporation, (216) 943-4200; personal
 communication with 0. Arrenholz, Versar Inc., May 22, 1986.
BTrace amounts are considered to be no more than a few
                                                       ppm.
                                  42

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              Table 18.   Weight Fractions of Functional  Components -
                         Floor Wax/Polish
 Functional  component
Weight fraction
           Examples
Carrier

Cleaning  ingredients/
   surfactants/emuls i f i ers
Coalescing agents


Fugitive ligand complex

Film-forming ingredients
Minimum film-forming
  temperature (MFT)
  modifier
Preservatives


Refractive index modifier

Solvents
Viscosity modifiers

Colorant
    0 - 0.88      Water

    0 - 0.084     Ammonium hydroxide, morpholine,
                  alkyl phenyl ethoxylates,
                  potassium hydroxide, ammonia,
                  di ethyl ami noethanol

    0 - 0.04      Glycol ether and derivatives,
                  zinc octoate

    0 - 0.0029    Zinc octoate

 0.05 - 0.96      Acrylic copolymer,  styrene
                  copolymer,  natural  and
                  synthetic resins, waxes,  tall
                  oil  fatty acid,  polyethylene
                  emulsion

    0 - 0.0703    Glycol ether and derivatives,
                  plasticizers,  ethylene glycol,
                  tall  oil  fatty acid,  dibutyl
                  phthalate,  tributoxyethyl
                  phosphate

    0 - 0.0032    Phenyl mercuric  acetate,
                  sodium metabisulfite
    0 - 0.39

    0 - 1.0
    0-0.19

    0  -  trace
Resins, waxes

Mineral spirits, diethylene
glycol monoethyl ether,
diethylene glycol monomethyl
ether, petroleum distillate

Resins
Source:  Gosselin et al.  (1984), Flick (1984), JRB (1983b).
                                       43

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              Table 19.   Functional  Components  as Weight  Fraction  in
                        Vinyl  Upholstery  Cleaners
Functional Component
Weight  fraction
Examples
Carrier

Cleaning agent


Coalescing agents
MFT Modifier
Propel!ant

Solvent



Surfactants
0.67 - 0.84         Water, Isopropyl alcohol

0    - 0.002        Nitrous acid, sodium salt
                    (corrosive inhibitor); Soaps

0.05 - 0.053        Diethylene glycol monoethyl
                    ether; Dimethyl polysiloxane
                    fluid; 2-butoxyethanol;
                    Polyethylene, Mono
                    (p-(l, 1,3,3-tetramethyl-butyl)
                    phenyl) ether glycols;
                    Propylene glycol methyl
                    ethers; Polyglycol ether.
Film forming ingredients     0    - >0.02
Odor forming ingredients     0    - 0.01
                    Carboxyvinyl polymer, Fatty
                    acid.
0.05 - <0.06        Diethylene glycol monoethyl
                    ether; Fatty acid;
                    Triethanolamine; 2-butoxy-
                    ethanol ; Polyethylene, mono
                    (p-(l,1,3,3-tetramethyl-butyl)
                    phenyl) ether glycols;
                    Propylene glycol methyl
                    ether; Polyglycol ether.
                    Amyl acetate, Lemon perfume
                    oil, Perfume.
0    - 0.08         Propane, Isobutane

0.04 - 0.19         Odorless mineral spirits;
                    Isopropyl alcohol; Amyl
                    acetate.

0    - 0.10         Nonionic surfactant; Nonionic
                    nonyl phenoxypoly
                    (ethyleneoxy) ethanol
                    surfactant; Polyoxyethylene
                    alcohol surfactant;
                    Triethanolamine.
Sources:  Battelle (1977); ORB (1983b);  Gosselin et al.  (1984); CIS (1986).
                                       44

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-------
        Instantaneous  release  1s a  single discharge  of  the  contents  of  a
        pressurized aerosol  product  for a period of  a few seconds  or  less.

     •   Continuous releases  -  generally long-term  releases  of a  chemical
        substance from a consumer product to an exposure medium.   An
        example of a continuous release 1s the discharge of the  contents
        of a pressurized aerosol product several times, where the
        Intervals of time between the discharge are  on  the  order of a few
        seconds.

     •   Time-dependent releases - generally long-term volatilization of a
        chemical substance from a consumer product applied  to a  surface.
        The time required to apply the product to  the surface 1s more than
        a few minutes.  Therefore, the rate of application  of the  product
        to the surface affects the total mass of chemical substance
        available for  release  from a given area of surface  at any  point 1n
        time during exposure.  An example of a time-dependent release Is
        the volatil- 1zat1on of a chemical substance from a film or
        coating applied to a surface at a constant rate, where the period
        of application 1s more than a couple of minutes.

Mechanisms Included 1n each of these groups are discussed  1n
Section 4.1.1.  Factors affecting dispersal of a chemical  in an exposure
medium  and the resulting exposure concentrations are reviewed 1n
Section 4.1.2.

4.1.1    Chemical Release Mechanisms

     Release or mass transfer  of a chemical  from a consumer product can be
thought of as the migration of the chemical in a mixture, either within
the  same phase (e.g., dispersion of a vapor in air), or from phase to
phase (e.g., liquid to gas).  The chemical  1n the consumer product may be
either  a direct additive or a residual contaminant.   Mass transfer occurs
by diffusion, where the driving force is  based on the phenomenon that
systems not in equilibrium will tend to move toward  equilibrium.  There
are actually two types of diffusion processes:  molecular diffusion and
eddy diffusion.  In both cases, diffusion occurs as  a result of a
concentration gradient;  however,  in eddy  diffusion,  the mass transfer is
greatly aided by the dynamic characteristics of air  turbulence (Welty
et al.  1976).

    Models describing mass transfer and concentration changes in the
consumer environment are based on a number  of simple physical laws.
These include Dalton's Law,  Raoult's Law,  Henry's  Law,  Graham's Law,  the
Ideal Gas Law, and  Pick's Law.  A general  knowledge  of  these laws  helps
the investigator to fully understand chemical  release processes and
models.  A review of these laws is  presented in Volume  12 and Volume 11
of Methods for Assessing Exposure to Chemical  Substances.
                                    46

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     Instantaneous chemical releases to air Include aerosolization and
dust entrapment or suspension.  Examples of each process include the
spraying '(e.g., either pressurized or by pump) of a cleaner in the home
and  the air suspension of soap powders poured from a container.  A brief
description of each is as follows:

     •  Aerosolization:  Aerosols are particles or droplets, ranging in
       size from about 0.15 to 5 microns, which are suspended or
       dispersed in a gaseous medium such as air (Sciarra and Stoller
       1974). . The phenomenon of aerosolization is related to the
       expenditure of energy for the propulsion or agitation of a
       liquid.  Movement of the aerosol is initially controlled by the
       expenditure of energy, and thereafter, by the processes of
       molecular and eddy diffusion, depending upon the aerosol size.

    •  Entrainment:  The suspension and movement of particulates are also
       controlled by energy (i.e., energy of agitation and/or dynamics of
       air flow); the aerodynamic behavior of particles is determined by
       particle size, shape,  and density.  The size, shape, and density
       of the particulate affects settling by dictating the extent to
       which gravity pulls the particle.

    Continuous and time-dependent chemical releases may involve the mass
transfer of a chemical substance across phase boundaries.   Processes
relevant to consumer exposure include volatilization of chemical
substances to air from liquids or solids  and leaching from solids to
liquids.  Migration via molecular diffusion controls the rate of movement
of a chemical to a phase boundary.  (The  term migration is used here only
to describe the movement of a chemical  within a solid (e.g.,  a polymer).)
Following is a brief review of the processes of volatilization, leaching,
and migration:

    •  Volatilization - The process by  which a chemical transfers into
       the vapor phase from a solid or  liquid.   Examples include the
       release of constituents from paints,  cleaning solutions, and
       plastic materials.

    •  Leaching - This term will  be used  to refer  to the release of a
       chemical from a solid  to a liquid, for example,  the leaching of
       chemicals from food containers (e.g.,  plastic,  cardboard) to the
       enclosed food.   Leaching rates are controlled by the migration of
       the chemical  to the surface of the solid and the solubilities of
       the chemical  in the two media.

    •  Migration - This term  will be used to refer  to the  movement  of a
       chemical within a solid matrix to  the surface of a  solid.   For
       consumer products,  this process  is generally only considered for
       the movement of relatively low molecular weight  substances from
                                    47

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       polymers (e.g., plastic and elastomeMc materials).  Molecular
       diffusion usually controls the rate of migration.  The diffusion
       rate of a compound is affected by the size of the molecule, the
       structure and characteristics of the surrounding matrix, and the
       attractive forces of the matrix constituents.  The migration
       phenomenon within polymer matrices is described in detail in
       Volume 11 of Methods for Assessing Exposure to Chemical Substances.

Models or algorithms and required input parameters for estimating the
above types of mass transfer rates are reviewed in Section 4.3.

4.1.2    Factors Affecting Exposure Concentrations

    Once a chemical is released into a medium (e.g., air, water) or to a
surface to which exposure may occur, a number of environmental factors
affect the concentration of the chemical in the media or on the surface.
These factors include the medium volume, surface area, room ventilation
rate, and mixing factor.  Each of these is briefly described below:

    •  Volume - This refers to the amount of air or liquid into which
       the chemical is released.   For chemicals emitted to air, this
       generally refers to the room volume.

    •  Surface Area - This factor is included in scenarios where coatings
       are applied, spilled, or sprayed onto surfaces.  A quantitative
       value for the area of a surface covered by a consumer product is
       needed to estimate several parameters required to assess
       exposure.  These include duration of  application of a consumer
       product in the form of a film or coating applied to a surface,
       mass of chemical substance applied to a surface, and release rates
       for volatile chemical substances (e.g.,  solvents)  in films  or
       coatings applied to surfaces.   As the area of surface covered by a
       film or coating increases, the mass of chemical substance on the
       surface increases, the amount of chemical  substance released to
       air from the film or coating on the surface increases,  and  the
       resulting concentration of the chemical  substance  in air increases.

    •  Ventilation Rate - Air ventilation effectively reduces  the  concen-
       tration of a chemical substance released to indoor air  by diluting
       the chemical.  The ventilation rate,  therefore, is important for
       calculating concentrations of chemicals  in indoor  air.   This is
       usually expressed in terms of an air  exchange rate,  which is
       defined as the rate at which indoor air  is replaced by  outdoor
       air.  Generic ventilation  rates for various building types  or
       rooms are discussed in Section 4.4.   Ventilation rates  are  also
       discussed in Volume 12 of  Methods for Assessing Exposure to
       Chemical Substances.
                                    48

-------
     •  Mixing Factor - The mixing factor, m, is an empirical number
       that accounts for room-specific effects on transport of chemical
       substances (Repace and Lowrey 1980).  Removal of chemical sub-
       stances is more rapid in a well-mixed atmosphere than in a poorly
       mixed, stable one.  Factors that affect the mixing factor include
       type and placement of ventilation grills, ventilation flow rates,
       inhomogeneous distribution of a chemical substance in a room,
       physical barriers, circulation fans, and room traffic (Repace and
       Lowrey 1980).  A mixing factor of 1 means that the room has ideal,
       perfect mixing.  Actual values usually range from 1/2 to 1/10
       (Repace and Lowrey 1980).

Models or algorithms including required input parameters and generic data
for  calculating exposure concentrations are discussed in Section 4.4.

4.2      Monitoring Data

     The most accurate method of estimating exposure to a chemical sub-
stance is via the use of monitoring data for the chemical in the media
of concern throughout the duration of exposure.  Initial efforts in a
consumer exposure assessment, therefore, should focus on gathering all
available monitoring data,  including the following:

     •  Indoor air concentrations
     •  Surface concentrations
     •  Concentrations in consumer products of contaminants of interest.

     Currently, there is no  automated data base or repository for any of
these types of data.  However,  indoor air data have been found  in
independent scientific studies  through a computer search of  the
scientific literature (e.g.,  chemical abstracts,  NTIS holdings, and other
bibliographic files such as  those in the DIALOG Information  Retrieval
Service).

    The Department of Energy and the CPSC sponsored  a successful  pilot
research  study of selected  indoor air pollutants  from which  development
of a more extensive data base is planned.   Studies  included  monitoring of
highly volatile organics such as benzene,  halogenated hydrocarbons,  other
chemicals  released from plastics and resins,  and  data on environmental
factors,  such as  air exchange rate,  temperature,  and  humidity of  indoor
environments sampled.  In general,  however,  assessment of exposure  to
chemicals  in consumer products  must  rely primarily  upon  the  estimation
procedures, models,  or algorithms discussed  below.

4.3      Methods  to Estimate  Release of  Chemical  Substances  from Consumer
         Products

    The release rate is a key parameter  required  to  estimate the
concentration of  a chemical  substance in an  exposure  medium  as  a  result
                                    49

-------
of a  continuous or time-dependent  release.  The factors that determine
the release  rate of a chemical   substance from a product vary depending
upon  whether the release  is  continuous or time-dependent.  These factors
also  differ  for releases  of  chemical  substances from (1) pressurized
aerosol products; (2) liquid  films on surfaces; and (3) bulk liquids and
solids.  More than one mechanism of  release may be applicable for a given
consumer product.  For example,  to account for all the release mechanisms
occurring as a result of  spray painting the walls of a room, one must
consider (1) the rate at  which the chemical substance is being discharged
from  the container; (2) the  rate at which the chemical substance
volatilizes  from the liquid  paint  film applied to the surface of the
wall; and (3) the rate at which  the chemical substance migrates through
the film that forms once  the  paint has dried.

4.3.1    Release Rate of  Chemical  Substances in Aerosol Consumer Products

    This method is recommended for estimating the continuous release rate
of the contents of a pressurized aerosol container to air.  The
continuous release can consist of  one continuous discharge of the
contents of a pressurized container or many discharges of the contents
during the period of active  use, provided the discharges occur within
short intervals of one another (I.e., on the order of seconds).  The
following equation is used to estimate the release rate of a chemical
substance from a pressurized  aerosol product.

                              .   WF x H x 0V                        ., ns
                              G- 	55	                        (4-1)

where

    WF = weight fraction  of chemical substance in product (unitless)
     G = release rate of  chemical  substance (mass/hr)
     M = mass of product discharged during active use (units of mass)
    0V = fraction of product  that  is overspray and does not contact
         intended target  (unitless)
    DD = duration of active discharge of the pressurized aerosol  product
         (hours).

General guidelines for estimating the parameters of equation (4-1)  are
presented in Section 3 of this volume.

    If the product is designed to be released into air rather than
directed at a surface, the entire mass of product released may be
considered overspray, and the value for 0V may be set  equal to one.
Products of this type include aerosol air fresheners,  pesticide space
fumigants, and solid room deodorizers.
                                    50

-------
     If the contents of the pressurized aerosol product are applied to a
surface, release of a chemical substance 1n the product will occur via
two  pathways: direct discharge to air with the contents of the aerosol
container and evaporation of the material deposited on the surface.  .Much
of the overspray from direct discharge will be deposited on unintended
surfaces.  The overspray, or portion of material that misses the intended
target, is the maximum amount of product that can be discharged directly
to air.  Equation (4-1) is recommended only for estimating the continuous
release rate of a chemical substance via direct discharge to air.  The
method for estimating the rate at which the chemical substance evaporates
from the material deposited on the surface is presented in the section
that follows.

4.3.2     Release Rate of Chemical Substances from Liquid Films Applied
          to Surfaces

     (1)  Assumptions.  The equations required to estimate the rate of
release of a chemical substance from a liquid film applied to a surface
differ for continuous and time-dependent releases.  Rate of release will
be considered continuous if the liquid is instantaneously sprayed or
spilled onto the surface; otherwise, the release will be time-dependent
so that the rate at which the film is applied and the change in mass of
the chemical substance released from the surface with time as the film is
being applied are taken into account.  For practical applications,  it is
best to consider the release rate to be continuous if the liquid film is
instantaneously spilled or sprayed onto a surface or if the time required
to cover the surface with the liquid film is less than a few minutes.  If
the time required to cover the surface with the liquid film is more than
a few minutes,  it is best to consider the rate of release to be
time-dependent.

    The difference between the continuous release rate and the time-
dependent release rate is as follows.  For a scenario in which the
release rate is  continuous, the amount of chemical substance remaining
on the surface  is the same for each unit of area at any given point in
time.  For a scenario in which the release rate is time-dependent,
however,  the amount of chemical substance remaining on the surface  is
different for each unit of area at any given point in time.   The
difference between these two scenarios is the rate at which the film is
applied to the  surface.  For a scenario in which the release rate is
continuous,  the  film is instantaneously applied to the surface.
Therefore,  the  rate at which the film is applied is not a parameter of
concern.   For a  scenario in which the release rate is time-dependent,
however,  the rate at which the film containing the volatile chemical
substance is applied affects the total mass of chemical substance
available for release from a given area at any point in time.

    The following example illustrates the concept of a time-dependent
release.   An individual paints a board that has a surface area of five
                                    51

-------
 square  feet.   The  paint  that  Is  ultimately applied to the board contains
 five  grams  of  a  volatile chemical  substance distributed evenly throughout
 the paint applied  to  the board.   In other words, the surface of the board
 will  be  coated with one  gram  of  the chemical substance for every square
 foot  of  board.   Assume that the  time  required for the chemical substance
 to evaporate from  the surface once it  1s applied is five minutes.  Further
 assume  that the  individual paints  the  board at a constant rate of one
 square  foot per  minute.   Therefore, the time required to apply the paint
 to the  board is  five minutes.  Figure  1 depicts the mass of volatile
 chemical substance remaining  on  the surface for each square foot of board
 as a  function  of time.   Values for the cumulative mass of chemical
 substance applied, the cumulative mass remaining on the surface of the
 board, and the cumulative mass released to air are also presented for
 each  minute after  painting is initiated.  Values for the mass released
 to air during  each minute are shown as well.

    It must be noted that, for this Illustration, instantaneous appli-
 cation of coating  to a surface area of one square foot was assumed at
 each  minute during application.   In theory, each square foot could be"
 divided  into any number  of units and could be analyzed in the same way
 as the five square foot  board used in this example.  The foundation of
 the time-dependent release is the assumption of instantaneous application
 of coating to  some fixed area of the total surface and initiation of
 chemical release at a constant rate at the Instant the application is
 completed.  The  accuracy of values predicted for the mass remaining and
 for the mass released using the  time-dependent release rate increases
with  decreasing  size of  area assumed to be Instantaneously coated.   For
 the purpose of assessing consumer exposure to chemical substances
 volatilizing from  coatings applied to surfaces, the surface area
 determined to be painted in one minute can probably be assumed to be
 coated instantaneously.

    (2)  Equations.  The following equation is used to estimate the
 release rate of a chemical substance for those scenarios in which the
assumption of a continuous rate of release is applicable.
where
     G =
     N =
    SA =
    MW =
                              N x SA x MW x 3600
release rate of chemical substance (grams/hr)
molar flux of pure chemical substance (mole/cm2-sec)
surface area covered by liquid film (cm2)
molecular weight of chemical substance (g/mole).
                                                          (4-2)
    Equation (4-5) is used to estimate the release rate of a chemical
substance for those scenarios in which the assumption of a time-dependent
                                    52

-------
                                                                 TIME DEPENDENT RELEASE
CAj







M













0.8
14












0.6
0.8

•Mf










M
0.6

M
1.8









M
M.

*:-
4l
Vs -S^:
•'Mil










ifr
JHL*.
*'i"V">W •
-'Mfv










«.'*"'
;₯:
*•*;-••"-•, , '
' > ..
TIME ELAPSED












^' "•

!^'














•"t- VJ '
•M>
















AFTER PAINTING
IS INITIATED
(MINUTES) 12 3456789 10
CUMULATIVE
MASS APPLIED
(GRAMS) 1.0 2.0 3.0 4.0 5.0
          CUMULATIVE
          MASS REMAINING
          ON SURFACE
          (GRAMS)           1.0

          CUMULATIVE
          MASS RELEASED
          TO AIR (GRAMS)     0.0

          MASS RE LEASED
          TO AIR DURING
          EACH MINUTE
          (GRAMS)
1.8
0.2
                                       0.2
            2.4
            0.6
                                                   0.4
                        2.8
                        1.2
                                                               0.6
                                    3.0
                                    2.0
                                                                           0.8
                                                2.0
                                                3.0
                                                                                       1.0
                                                            1.2
                                                            3.8
                                                                                                   0.8
                                                                        0.6
                                                                       4.4
                                                                                                               0.6
                                                                                    0.2
                                                                                    4.8
                                                                                                                           0.4
                                                                                                5.0
                                                                                                                                       0.2
                                                                                                             - SHADED BLOCK DENOTES VOLATILE
                                                                                                               SUBSTANCE REMAINING ON SURFACE
                                            FIGURE  1.  MASS OF VOLATILE CHEMICAL SUBSTANCE REMAINING ON
                                                       SURFACE OF EACH SQUARE FOOT OF BOARp AS A FUNCTION
                                                       OF TIME                                :

-------
rate of  release  1s applicable.   Equation  (4-5)  is the product of
equations  (4-3)  and  (4-4).

                            GN = N x MW x 3600                      (4-3)

where

    GN = Mass flux (g/cm2-hr).

Equation (4-4) is as follows:


                               AR = -&-                            (4-4)

where
    AR = rate of application of film to the surface (cm2/hr)
    SA = surface area covered (cm?)
    ta = duration of application (hours).

The resulting equation, (4-5), is expressed below:

                       GNAR = N x MW x 3600 x (SA/ta)               (4-5)

where

    Gj\|AR = time-dependent release rate (g/hr2)

and the other variables in equation (4-5) are as defined previously.

    The rate is expressed in units of mass/hr2 because the mass  released
is changing with time.   When this release rate is used in equations to
calculate indoor air concentrations resulting from a time-dependent
release situation,  the  resulting units of concentration are expressed  in
the correct units (e.g.,  mass/volume).

    Both the continuous and time-dependent release rates are a function
of the rate or molar flux of diffusion of a chemical substance,  N,
expressed in moles/time-area.   This rate is essentially the average flow
of the diffusing molecules per unit area (during diffusion) per  unit
time.   It depends not only on the concentration gradient, but also  on  the
characteristics of  the  diffusing compounds and on environmental  parameters
(temperature, pressure, etc.).  The following equation is used to calculate
the molar flux of a chemical substance.

                            -P x DAB x (PB2 - PB1)

                        N=   LxRxTx                             "
                                    54

-------
where

     N    = molar  flux  (mole/cm2-sec)
     P    = atmospheric  pressure  (atm)
     °AB  = diffusion coefficient  of chemical  substance  in air at  25°C and
          1 atmosphere  (cm2/sec)
         = partial pressure of chemical substance at  interface of  liquid
          and gas film  (atm)
         = partial pressure of chemical substance at  interface of  gas
          film and main air stream (atm)
     L    = gas film thickness (cm); (A value  of 2.54  cm or 1 inch  can be
          assumed if no other information is available.)
     R    = gas constant, 82.05 atm-cm3/mole-°K
     T    = temperature  (°K); (A value of 298°K or 25°C is usually
            assumed to  represent ambient conditions.).

Equation (4-7) is used  to calculate the parameter, (P/\)lm, in
equation (4-6).

                                    PA2 - PA1
                        (PA)lm =  ,_,D—rr—:—                      (4-7)
                         H/      Tn(pA2/pAl)
where
        = partial pressure of air at Interface of gas film
          and main air stream (atm)
        = partial pressure of air at interface of liquid and
          gas film (atm) .
    The variables PA-| , P/^t PBI •  and PB2 mus't be determined
prior to calculating (P/\)lm and N.  The partial pressures of a
two-component system form an integral part of the molar flux
calculations.  In computing the partial pressures, one has to consider
the two Interfaces involved 1n the diffusion process.  Diffusion is
controlled by the concentration gradient of B in a stagnant gas film on
the surface of the liquid film.  Considering the liquid and air as the
two components of a system, the interfaces could be defined as (1) the
interface between the liquid and  the gas film and (2) interface between
the gas film and the main air stream (Versar 1984b).   A value of 1 atm
can be assumed for P^-   The value of Pg2, usually assumed to be
zero, is calculated as follows:

                               PB2  = 1-PA2                          (4-8)

where these variables are as previously defined.  The value of PA-| is
calculated as follows:
                                    55

-------
                                PAI - I-PBI

where  these  variables are as previously defined.

    The  following  equation  1s used to calculate
                                      VP
                                 PB1 = ^                             (4-10)
where
    VP =  the vapor pressure of the chemical substance at the desired
          room temperature (mm Hg)
      P =  atmospheric pressure at the desired altitude (mm Hg); (e.g.,
          P = 760 mm Hg at sea level).

The values R and T are as defined previously.

    To calculate the molar flux, N, a value for the diffusion coeffi-
cient, DAB» °f the chemical substance in air under the appropriate
environmental conditions must be obtained.  Use of experimentally
determined values 1s preferred 1f they are available for the chemical
substance being examined under the specific environmental conditions
under which exposure is occurring.  In the absence of such data, the
Fuller, Schettler, and 61dd1ngs (FSG) method or the Wilke and Lee (WL)
method can be used to estimate the diffusion coefficients (Lyman et al.
1982).  The FSG method 1s reportedly applicable to nonpolar gases at low
to moderate temperatures, and the WL method 1s applicable to a wide
range of compounds over a fairly wide temperature range.   The WL method,
presented here, is preferred because the average number of errors
obtained with this method is considerably less than obtained with the
FSG method.


           (0.00217 - 0.00050  Jl/M  + 1/M R)T3/2 -v/l/M  + 1/M
     D.    V - - - * - —^ - * - 2-
      .R =

                                  P "AB
where
            DAB = diffusion coefficient (cm2/sec)
              T = absolute temperature (°K)
           , MB = molecular weight of air and chemical substance,
                  respectively
              P = absolute pressure (atm)0
            °/\B = characteristic length,  A (Angstrom units)
              Q = collision integral.
                                    56

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     The  collision  Integral, Q,  1s a  function of the molecular energy of
 attraction,  c, and the Boltzmann Constant, kg, as given below:


       a .   -V  —^	s	"—              (4-12)
              (T*)u    exp  (T*d)   exp (T*f)   exp (T*h)

 where

     the  values a-h are as  given 1n Chapter 17, Lyman et al. (1982), and


                  T* =          T             .                      (4-13)
                       V(e/KR).  («/KR)R
                        '     D H      D D

     Values of e/kg are given 1n Treybal (1968) for some of the more
 common gases.  Values for  other gases can be approximated using the
 following formula (Lyman et al. 1982):


                           e/kg = 1.15Tb                            (4-14)

where

     Tfc  = normal  boiling point (°K).

     The characteristic length, o^g,  can be calculated using the
following relationship:

                                    CA + °B
                            °AB =      3(4-15)
where
         c/\ = 3.711 A (angstrom units)


         OB = 1.18V'B1/3                                            (4-16)


         'g = molar volume of the chemical  substance at Its  normal  boiling
              point (cm3/mole).  (See Treybal  (1968) or Lyman et al.  (1982)
              for atomic and molecular volumes.)
    Fuller, Schettler,  and Giddings (FSG)  (1966)  present a  simplified
approach for calculating the diffusion coefficient,  D^g.  The  method  Is
applicable for nonpolar gases In air at low to moderate temperatures:
                                    57

-------
DAB =
10
P
-3 T1.75 -

-------
            Table 20.  Diffusion Coefficients  (@ 25°C and  1 atm)
                       for Selected Organic Chemicals in Air
Chemical
Hexane
Benzene
Toluene
Benzyl alcohol
Chlorobenzene
Nitrobenzene
Benzyl chloride
o-Chlorotoluene
m-Chlorotoluene
p-Chlorotoluene
Diethyl phthalate
Di butyl phthalate
Diisooctyl phthalate
Chlorofonn
Carbon tetrachloride
1 ,1-Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Di ch 1 oroethyl ene
Vinyl chloride
1 , 1 , 1 -T r i ch 1 oroethane
1 , 1 , 2-T r i ch 1 oroethane
1 ,1 , 2, 2-Tetrachl oroethane
Trichl oroethyl ene
Tetrach 1 oroethyl ene
Pentach 1 oroethane
Hexach 1 orobenzene
Molecular
weight
86.17
78.11
92.13
108.13
112.56
123.11
126.58
126.58
126.58
126.58
222.23
278.34
390.56
119.39
153.84
98.97
98.97
96.95
62.50
133.42
133.42
167.86
131.40
165.85
202.31
284.80
Diffusion coefficient
(cn^/sec)
0.0732
0.0932
0.0849
0.0712
0.0747
0.0721
0.0713
0.0688
0.0645
0.0621
0.0497
0.0421
0.0377
0.0888
0.0828
0.0919
0.0907
0.1144
0.1225
0.0794
0.0792
0.0722
0.0875
0.0797
0.0673
0.12
Source:   Schwope et al.  (1985).
                                         59

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exhibit a rate of evaporation different from that which 1t exhibits 1n
the pure state.

    To adjust the release rate of the pure chemical to account for
non-Ideal behavior as a result of Interactions among mixture components
and to account for the effects of dilution of the mixture In water or
other solvents, the release rate of the pure chemical must be multiplied
by a correction factor.  The correction factor-can be, In order of
preference, the activity coefficient, the mole fraction, or the weight
fraction of the chemical 1n the mixture from which It 1s evaporating.

    Methods for estimating activity coefficients for two-component
systems are presented 1n the Handbook of Chemical Property Estimation
Methods (Lyman et al. 1982).  Although the activity coefficient Is the
most accurate correction factor, the detailed data required regarding
components of the mixture and the length of time required to complete the
calculations are major disadvantages.  The weight fraction of each
component of the mixture must be known.  In addition, the activity
coefficient for each component with each of the other components of the
mixture must be obtained.

    A simpler approach for obtaining the correction factor 1s to use the
mole fraction of the chemical in the mixture as a substitute for the
activity coefficient.  The mole fraction,  although less accurate than the
activity coefficient as a correction factor, is easier to calculate.   To
calculate the mole fraction, the weight fraction and the molecular weight
of each component of the mixture must be known.

    In the absence of data on the weight fraction and/or molecular weight
of each component of a mixture,  it is suggested that the weight fraction
of the chemical  substance in the mixture be used as a correction factor.
Use of the weight fraction as a correction factor provides the lowest
degree of accuracy of the three variables  suggested.   The major
advantage,  however,  1s the ease with which a value for correction  factor
can be obtained.

4.3.3    Chemical  Release from Bulk Liquids and  Solids

    This method  can  be used to calculate release rates of chemical  sub-
stances migrating through  bulk liquids and solids.   Applicable scenarios
include dermal  contact with solid objects, contaminant release from
containers  to food or liquids intended for consumption,  release from open
containers  of bulk liquids to air,  and release  from dry coatings  and
solid objects to air.

    The optimal  way  to determine the diffusion  coefficient of a migrant
in a liquid or solid is experimentation.   Schwope et  al.  (1985) present
experimentally determined  diffusion coefficients  for  the diffusion  of
                                    60

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 migrants  through  selected  polymers  as  a  function  of  the molecular weight
 of  the  migrant.   The diffusion  coefficient  through a specific  polymer  can
 vary  by several orders  of  magnitude depending  on  the molecular weight  of
 the migrant.   The values of  these diffusion coefficients  range from
 10~7  to ICh4 cm2/sec for migrant in silicone rubber,  the  most  flexible
 material  discussed  in Schwope et al. (1985), and  from ICH7 to 10~7 cm2/sec
 for migrant in unplasticized PVC, the  most  rigid  material discussed in
 this  study.  By comparison,  the corresponding  diffusion coefficients
 through air range from  10~2  cm2/sec  to 1(H cm2/sec  (Schwope et al.
 1985).  D1ffusi.cn through  the polymer  is usually  the  rate controlling
 step  for  migrant  release.

    Experimental data are  not available  for most  migrant/polymer pairs.
 Schwope et al. (1985) present an empirical approach  to estimating the
 diffusion coefficient of a migrant  through a polymer,  knowing  only the
 molecular weight of the migrant and  the  general type  of polymer involved.

    Diffusion coefficients for migrants  in a water solution can be
 estimated by the Wilke-Chang method  (Reid et al.  1977) using the
 following equation:
where
              Dw = (7.4 x 10-8 (4>M)1/2 T)/nwVB
0.6
                     (4-18)
          4> = solution association constant (2.26)
          M = molecular weight of migrant
          T = temperature (°K)
         nw = viscosity of water in cp (1.002 at 20°C and 0.8904
              at 25°C)
         VB = molar volume of migrant at boiling point (cm3/g-mole).

    At 20°C, diffusion coefficients for inorganic and organic migrants
in water typically range from 0.4 x 10-5 to 5 x 10-5 cm2/sec.  A
listing of experimentally determined diffusion coefficients for selected
migrants in water is presented in Table 21.

    Schwope et al. (1985) have developed a method for estimating the
fraction of total migrants released over a given time period when
diffusion through a polymer is the rate controlling step.  The most
simplified version of the method is shown here; it assumes that the
external phase is well mixed and that it provides no resistance to
migrant release from the polymer.  The method requires calculating two
dimensionless parameters, y and o, using equations (4-19) and (4-20),
respectively.
                                   =  Dt/L2
                     (4-19)
                                    61

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Table 21.   Diffusion Coefficients in Aqueous Solutions
           at Infinite Dilution
Chemical
Hydrogen
Oxygen
Nitrogen
Nitrous oxide
Carbon dioxide
Anmonia
Methane


n-Butane


Propyl ene
Methyl cyclopentane


Benzene



Ethyl benzene


Methyl alcohol
Ethyl alcohol

Temperature
(°C)
25
25
29.6
29.6
25
25
12
2
20
60
4
20
60
25
2
10
20
60
2
10
20
60
2
10
20
60
15
10
15
25
Diffusion coefficient
in water (x 10"^)
(cmZ/s)
4.8
2.41
3.49
3.47
2.67
2.00
1.64
0.85
1.49
3.55
0.50
0.89
2.51
1.44
0.48
0.59
0.85
1.92
0.58
0.75
1.02
2.55
0.44
0.61
0.81
1.95
1.26
0.84
1.00
1.24
                           62

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                          Table 21.   (continued)
Chemical
n-Propyl alcohol
Isoamyl alcohol
Allyl alcohol
Benzyl alcohol
Ethyl ene glycol



Glycerol
Acetic acid
Oxalic acid
Benzoi c acid
Ethyl acetate
Urea

Di ethyl ami ne
Acetonitrile
Aniline
Furfural
Pyridine
Vinyl chloride

Temperature
(°C)
15
15
15
20
20
25
40
55
70
15
20
20
25
20
20
25
20
15
20
20
15
25
50
75
Diffusion coefficient
in water (x 10~5)
(cm2/s)
0.87
0.69
0.90
0.82
1.04
1.16
1.71
2.26
2.75
0.72
1.19
1.53
1.21
1.00
1.20
1.38
0.97
1.26
0.92
1.04
0.58
1.34
2.42
3.67
Source:  Schwope et al.  (1985).
                                     63

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where

          D  = diffusion  coefficient  of the migrant  through the  polymer
            (cm^/sec)
          t  = time  of  release  (seconds)
          L  = thickness  of  source  (cm) in cases of  one-sided exposure;  in
             cases of two-sided exposure use a value  for L corresponding
             to half  the thickness  of the source.

                                  a  = aK/L                            (4-20)

where

          a  = external phase volume  divided by surface area of  source (cm)
          K  = partition  coefficient  (dimensionless  ratio of concentration
             1n external phase volume to the concentration in  source).

    The calculated values  of (p and  a can be used with Figure 2 to
determine the fraction, F, of migrant which has been  released  from the
polymer at  time, t.  The fraction of migrant released at time, t, can
then be multiplied by the  original  concentration in the polymer and  the
polymer volume to find  the total  mass of migrant released as follows:

                               Mt = F CSOVS                          (4-21)

where

       M^- = mass of migrant released (g)
        F = fraction of migrant released
      Cso = original concentration  in polymer (g/cm3)
       Vs = volume of polymer (cm3).

    The mass,  Mt, should be divided by the time to get the average
release rate during the period.   This release rate can be used in the
appropriate equations presented in  Section 4.4.2 to calculate average
concentrations resulting from continuous releases.

    Other methods of estimating release rates can also be found in
Schwope et al. (1985),  including methods for estimating the rate of
migrant release from one phase to another,  where diffusion through the
external phase or diffusion through a boundary layer is rate-controlling
or where partitioning between the polymer and external phase affects the
migration rate.

4.4      Methods for Estimating Concentrations in Indoor Air

    The following subsections present equations used to estimate
concentrations of chemical  substances to which consumers may be exposed
                                    64

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CTl
tn



                                  "iv=TT4 •T-~I. !  ' i    •  :   ; . ,  i t  > i

                                      "~"'~~'"'
                                                   TmfrHT

          10
                                                                                                                                              to"
         Source:  Schwope et al.  (1985).

                                      Figure 2.  Fraction migrated as  a  function oftyfor well-mixed domains.

-------
as a  result of  releases of chemical substances from consumer products to
room  air.  The  equations presented for estimating the concentration at
any specified time during exposure and for estimating the average
concentration during the period of exposure are those used in the
Computerized Consumer Exposure Model (CCEM).  These equations are
applicable to any situation in which release of the chemical substance
from  the consumer product is to a volume of air that may be considered a
single compartment.  Consequently, these equations are designed to
estimate concentrations 1n a single room containing a consumer product
that  releases a chemical substance.  These equations include no
parameters to account for the flow of air from one indoor compartment to
another.  They  are, therefore, not Intended to be applied to estimate
concentrations  of chemical substances in rooms other than the room
containing the  consumer product from which the chemical is released.
These equations are also not intended to be used to estimate average
concentrations  of chemical substances in entire residences.
Multi-compartment models that take into account air flow patterns from
one indoor air  compartment to another and for specific configurations of
the types of residences being considered (e.g., split-level home,
two-story home, rambler, office building) 1n addition to other applicable
parameters are more suitable for this purpose.

    Releases of chemical substances from consumer products are
characterized in this methodology as Instantaneous releases, continuous
releases, or time-dependent releases.  Appropriate equations for
estimating concentrations in indoor air are shown for each type of
release.  The equations for estimating concentrations of chemical
substances in Indoor air as a result of continuous and time-dependent
releases are derived from equations for estimating concentrations
resulting from  Instantaneous releases.   A brief discussion of
concentrations  resulting from instantaneous releases of chemical
substances is presented in Section 4.4.1.  For details on the derivation
of equations for all types of releases, refer to Volume 12 of Methods for
Assessing Exposure to Chemical Substances.   Equations presented for
estimating concentrations resulting from continuous  releases of chemical
substances are used in the continuous release - aerosol  and the
continuous release - film modules of CCEM.   The continuous release -
aerosol  module estimates concentrations for instantaneous and continuous
discharges from aerosol  consumer products.   Equations for estimating
concentrations resulting from time-dependent releases of chemical
substances are used in the time-dependent release module of CCEM.
Uniform distribution of the releases throughout the  room is assumed for
instantaneous, continuous,  and time-dependent releases.

    In all three modules of CCEM,  average concentrations can be
calculated for any interval  of time after release of the chemical
occurs.   The time at the beginning of exposure,  t^,  and  the time  at the
end of exposure, te, are used to specify the interval.   If the  time at
                                    66

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the beginning of exposure 1s not specified, the time at the beginning of
exposure 1s assumed to be the time at the beginning of release, t0.
The time at the beginning of release 1s always zero.  When specifying the
time at the beginning of exposure, a time cannot be selected that occurs
before release of the chemical begins (I.e., t^ must be greater than or
equal to t = 0, or t0).  The time at the beginning of exposure must
also be less than the time at the end of exposure (e.g., t& must be
less than te).

    In all three modules of CCEM, the duration of exposure does not have
to correspond to the Interval of time for which the average concentration
is estimated.  For example, a chemical is released continuously from a
film on a surface for a period of 30 days.  The receptor, however, is
only exposed to the chemical for a period of 8 hours per day.  This
corresponds to one exposure event.  In this case, the average
concentration would be estimated for the interval from t = 0 to
t = 720 hours (24 hours/day x 30 days).  To calculate exposure, the
duration of exposure would be set equal to 8 hours per event and the
annual frequency of exposure would be set equal to 30 events per year.

4.4.1    Concentrations Resulting from Instantaneous Releases of Chemical
         Substances

    These methods are most applicable to exposure scenarios in which a
short-term release of a chemical substance occurs (e.g., on the order of
a few seconds).  Examples include release of a chemical  substance due to
a single discharge of product from an aerosol  spray container or a spill
of a volatile liquid or fine powder.   The basic criterion for classifying
a release as instantaneous is that the initial concentration, C0,  is
the maximum concentration to which an individual  1s exposed and that the
concentration decreases and approaches zero as time progresses.

    The following equation is used to estimate the concentration
resulting from an instantaneous release to indoor air at any time,  t,
during a period of exposure (Porter 1983).

                              C  =  C0e-m(Q/v)t                        (4-22)

where

     C = concentration of chemical substance at any time,  t,  during
         exposure (mg/m3)
    C0 = initial  concentration of chemical  substance (mg/m3)
     m = mixing factor (unitless)
     Q = ventilation flow rate (m3/hr)
     V = room volume (m3)
     t = time during exposure period  (hrs).
                                    67

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    The  Initial concentration, .C0, can be estimated for chemical
substances discharged from aerosol containers using the following
equation.


                            r    WF X M X FA
                            Co =      y                             (4-23)

where

    WF = weight fraction of chemical substance In product (unitless)
     M = mass of product released (mass)
    0V = fraction of product released that 1s overspray (unltless)
     V = room volume (m3) .

For products that are spilled, the following equation can be used:

                                  M x H x FA                       (4-24)
where

    FA = fraction of spilled material entrained 1n air (unltless) and the
         other variables are as defined previously.  Methods for
         estimating WF, M, FA, and 0V are presented 1n Section 3 of this
         volume.

    The equations used to estimate concentrations resulting from
continuous and time-dependent releases are derived from equations for
estimating concentrations resulting from Instantaneous releases.  It must
be noted that any type of release requires some amount of time to occur
and, by definition, cannot be truly Instantaneous.  For Increased
accuracy, It Is suggested that equations for estimating concentrations
resulting from continuous releases be used for those situations 1n which
a release might be characterized as Instantaneous.

    The mixing factor, m, is an empirical number that accounts for
room-specific effects on transport of chemical substances (Repace and
Lowrey 1980).  Removal of chemical substances is more rapid in a well-
mixed atmosphere than in a poorly mixed, stable one.  Factors that affect
the mixing factor include type and placement of ventilation grills,
ventilation flow rates, inhomogeneous distribution of a chemical substance
in a room, physical barriers, circulation fans, and room traffic (Repace
and Lowrey 1980).  A mixing factor of 1.0 implies ideal mixing.  If the
environmental conditions are such that the air throughout the room is
continuously and vigorously mixed, then mixing of air in the room is con-
sidered ideal.  Table 22 presents values for mixing factors recommended
for several common air supply system configurations.  According to Repace
and Lowrey (1980), the best standard condition is the perforated ceiling
                                    68

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       Table 22.  Values for Mixing Factor Recommended for Several
                  Common Air Supply System Configurations
Configuration of air supply system                   Mixing factor


Perforated ceiling*                                        1/2

Trunk system with amenostats                               1/3

Trunk system with diffusers                                1/4

Natural draft and ceiling exhaust fans                     1/6

Infiltration and natural draft                             1/10


* This is the best standard condition.

Source:  Repace and Lowrey (1980).
                                    69

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air  supply  system configuration, which has a  recommended value of 1/2 for
mixing  factor.  The air  supply system configurations presented In Table 22
are  listed  in order of most to least thorough mixing of room air.

     The ventilation flow rate, Q, 1s the product obtained from multiply-
ing  the room volume by the air exchange rate.  Table 23 presents values
for  typical volumes of rooms in houses and apartments.  According to
figures from the Bureau  of the Census, the average floor area of new
houses  in 1983 was 1780  square feet.*  The average ceiling height is
eight feet.  The average volume of a new house is, therefore, estimated
to be 14,240 cubic feet, or approximately 403 cubic meters.  The main
living  space, including  living room, dining room, kitchen, one bedroom,
and  one bath 1s estimated to be from 110 to 131 m3.  The actual values
for  room volume are based on professional judgment.  Typical air exchange
rates 1n residences are  presented in Table 24.

     The average concentration following an instantaneous release can be
estimated by Integrating equation (4-22)  from the time of Instantaneous
release to any point in  time after the Instantaneous release occurs.  The
following equation 1s used to estimate the average concentration
following an Instantaneous release.
                     C;
                             -C0V\ e -m(Q/V)t + C0V
                              mQ  /	rnO
                                                       u
                                      tu - tc

where
0            (4-25)
    t0 = time at which instantaneous release occurs (hours)
    tu = any point in time after the instantaneous release occurs
         (hours)

and all other variables 1n equation (4-25) are as defined previously.
It should be noted that equation (4-25) will overestimate average
concentrations resulting from Instantaneous releases of aerosols because
it does not include a factor to account for gravitational settling of
particulates.  The derivations of equations (4-22) and (4-25)  are
presented in Volume 12 of Methods for Assessing Exposure to Chemical
Substances.

    It must be noted that the time at the beginning of exposure and the
time at the end of exposure can be specified at any time after release
begins.  The only stipulation is that the time at the beginning of
     Stan Rollock,  Bureau of the Census,  Annual  Housing Survey,  personal
     communication  with Peggy Redmond of  Versar  Inc.,  April  5,  1985.
                                    70

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                      Table 23.  Typical Roam Volumes
    Location                                 Volume* (m3)
    Typical  House

          Master  bedroom                          41
          Standard  bedrooms  (2)                    40
          Baths  (2)                                18
          Living  room                             41
          Dining  room                             20
          Kitchen                                 20
          Basement  (partial)                      125
          Garage  (1  car)                           60
          Foyer/ha11ways                           15

                               Total             380+
   Typical Apartment

         Master bedroom                          41
         2nd bedroom or den                      20
         Bath                                     9
         Living/dining room                      61
         Kitchen                                 20
         Foyer/hallways                          15

                               Total             166
*A11 values for room volume are Versar estimates.

+Total volume  is less than the value of 403 cubic meters estimated
 from Annual Housing Survey data; the difference between these totals
 can be attributed to the exclusion of closets in the total volume for
 typical  house presented in this table.
                                    71

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         Table 24.  Air Changes Occurring Under Average Conditions in Residences
                    Exclusive of Air Provided for Ventilationa
          Kind of room                                  No. air changes/hour (ACH)



Rooms with no windows or exterior doors                             0.5

Rooms with windows or exterior doors on one side                    1

Rooms with windows or exterior doors on two sides                   1.5

Rooms with windows or exterior doors on three sides                 2

Entrance halls                                                      2
aFor rooms with weatherstripped windows or with storm sash, use two-thirds of
 these values.

Source:  American Society of Heating, Refrigerating, and Air-Conditioning Engineers,
         Inc. (1977).
                                             72

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 exposure  must  occur  before  the  time at  the  end of exposure.  The average
 concentration  during  exposure 1s  calculated  using equation  (4-25).  The
 variable,  t^,  1s  substituted for  t0, and the  variable, te,  1s
 substituted  for tu 1n  equation  (4-25).

 4.4.2     Concentrations  Resulting  from  Continuous Releases  of Chemical
          Substances

    Continuous release scenarios  are characterized by a chemical substance
 that 1s released  at a  constant  rate until the period of exposure ends or
 the source ceases to  emit the chemical  substance, whichever comes first.
 If the exposure continues after the source  ceases to emit the chemical
 substance, equation (4-22)  for  calculating  room air concentrations during
 Instantaneous  releases 1s used.   The value  for C0 used 1n equation
 (4-22) would be the value of C  at  the time at which the solvent ceased
 to be emitted.  Examples of scenarios 1n which the rate of  release 1s
 continuous include (1) single releases  of chemical substances from
 pressurized aerosol products for time periods of more than a few seconds;
 (2) multiple discharges  of  chemical substances from pressurized aerosol
 products  1n which each discharge occurs within a short time of the other;
 (3) releases of chemical substances from films formed- when products are
 spilled or sprayed Instantaneously onto surfaces; and (4) releases of
 migrants  from  solid matrices or bulk liquids.  Equation (4-26) is used to
 calculate the  concentration in the room at any time, t, prior to cessation
 of release of  the chemical  substance.  The initial concentration is
 assumed to be  zero.

                            _G   _G e-m(Q/V)t                       (
                         C ~ mQ   mQ                                 (

 If the initial concentration is not equal to zero,
where
                     c .  .1, C0 _ _G e-n
                          mQ        mQ
    G = release rate of the chemical substance calculated using the
        appropriate method (see Section 4.3) (mg/hr)
    m = mixing factor (unitless)
    Q = ventilation flow rate (m3/hr)
    V = room volume (m3) .

Equation (4-28), the integrated form of equation (4-26),  is used to
calculate the average concentration in the room during release of the
chemical substance.
                                   .73

-------
                    Cave =
                             G
                            mQ
                                      GV \ e-m(Q/V)t
                                     tg - t0
                                                                    (4-29)
where
    tg = time at which release of the chemical substance ceases (hours),

and the other variables of equation (4-28) are as defined previously.   The
room air concentration at the time at which the chemical substance Is  no  ,
longer released, C^g, 1s calculated by substituting tg Into equation
(4-26).  For continuous releases, the parameter,  tg, is calculated using
the following equation:
                                  tg =
                                                                    (4-29)
where

    H

    G
       = mass of chemical substance released from aerosol  product,  or
         mass applied, sprayed, or spilled onto a surface
       = release rate of the chemical  substance calculated using  the
         appropriate method (see Section 4-3)  (mass/hour).
    Equation (4-30), a variation of equation (4-22),  Is  used  to  calculate
the room air concentration at any time,  t,  after release of  chemical
substance from the source has ceased.
                           C  = ctge-m(Q/V)(t-tg)
                                                                    (4-30)
Equation (4-31) Is used to calculate the average concentration  from  the
time the release of chemical substance has ceased until  any  point  In  time
greater than the time at which release of the chemical  ceases.
                    *
                    tg
                             e-m(Q/V)  (t-tg
                            v,
                                                                    (4-31)
where

    tu = any point 1n time greater than the time  at  which  release  of
         the chemical ceases (hours).

If average concentrations are desired  for a period  starting  before
release ceases and ending after release of the  chemical  substance  from
the source has ceased,  the average concentration  during  this  period can
                                    74

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                                        ave (after release)
be estimated by calculating a time-weighted average of the average
concentration during release and the average concentration after release
has ceased:

    Cave (during period that starts before release ceases, but ends
         after release ceases) =
C                     x
 ave (during release)
The derivations of equations (4-26) through (4-31) are presented In
Volume 12 of Methods for Assessing Exposure to Chemical Substances.

    In estimating average concentrations during exposure, It must be
noted that the time at the beginning of exposure and the time at the end
of exposure can be specified at any time after release begins.  The only
stipulation 1s that the time at the beginning of exposure must occur
before the time at the end of exposure.  Three possible cases for the
time at the beginning of exposure and the time at the end of exposure are
the following:

    • Case 1:   The time at the beginning of exposure and the time at the
               end of exposure are less than the time at the end of
               release.  In this case, the average concentration during
               exposure 1s calculated using equation (4-28).  The
               variable, t^, 1s substituted for t0 and the variable,
               te, Is substituted for tg In Equation (4-28).

    • Case 2:   The time at the beginning of exposure Is less than the
               time at the end of release and the time at the end of
               exposure 1s greater than the time at the end  of release.
               In this case, the average concentration during exposure 1s
               calculated using equations (4-28),  (4-31),  and (4-32).
               The variable, t^, Is substituted for t0 In equation
               (4-28).  The variable, te, Is substituted for tu In
               equation (4-31).  The average concentration during release
               obtained from equation (4-28) and the average
               concentration after release obtained from equation (4-31)
               are used In equation (4-32) to obtain the average
               concentration during exposure.   In  addition,  t^ Is
               substituted for t0 and te Is substituted for  tu In
               equation (4-32).

    • Case 3:   The time at the beginning of exposure and the time at the
               end of exposure are greater than the time at  the end  of
               release.   In this case,  the average concentration during
               exposure Is calculated using equation (4-31).   The
               variable, tj-,, Is substituted for tg,  and the  variable,
               te, Is substituted for tu In equation (4-31).

                                    75
                                                                           (4-32)

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4.4.3    Concentrations Resulting from Time-Dependent Releases of
         Chemical Substances

    The following equations are applicable for estimating concentrations
that occur when the rate of release of a chemical substance Is time-
dependent.  These equations are applicable to scenarios In which a
coating or film containing the chemical substance for which exposure Is
being assessed 1s applied to a surface and the time required for
application 1s more than a few minutes.  To use this method, the assessor
must first ascertain whether the time for evaporation of the chemical
substance from the film, once It 1s applied to the surface (tg), 1s
less than, greater than, or equal to the time required to apply the film
to the surface (ta).  A method for estimating the time required to
apply a film to a surface 1s presented 1n Section 3.1 of this volume.
The following expression 1s used to estimate tg for a time-dependent
release.

                             tg  =  M/ta/GNAR                       (4-33)

where M 1s the total mass of chemical substance 1n the film applied
to the surface and G^AR 1s calculated using the method cited 1n
Section 4.3.

    This method for estimating tg assumes that evaporation occurs at a
constant rate.  Because of the effect that drying of the coating or film
may have on the release rate and because some chemical substances do not
evaporate completely from the film or coating before the coating dries
(Newman et al. 1975; Newman and Nunn 1975), the assumption of constant
release until  the entire mass of chemical substance 1s released may not
be true.  It 1s recommended that the value of tg obtained using
equation (4-33) be used only to estimate concentrations during release up
to the time reported for the specific coating to form a dry film, If this
time is known.

    Four equations are used to calculate concentrations in indoor air
resulting from time-dependent releases of chemical substances.   These
equations mathematically describe four physical  situations that occur at
specific intervals that characterize a time-dependent release.   For the
case 1n which  the time for evaporation of the chemical substance from the
film once 1t 1s applied to the surface 1s less than the time to apply the
film to the surface (Case 1),  a description of the physical  situation
during each of the four Intervals follows:

(1) t0 < t < tg:  Mass  of chemical  substance released is increasing
                 and concentration at any time,  t, is  increasing during
                 this  interval.   The mass of  chemical  substance released
                 1s increasing because of the additional  mass  being
                 applied to the surface.
                                    76

-------
 (2) tg < t < ta: The mass of chemical  substance released remains
                 constant and the concentration 1s Increasing.  The
                 additional mass applied to the surface 1s balanced
                 equally by the portion of the surface from which the
                 chemical has already  evaporated.

 (3) ta < t < tr: The variable tr denotes the time at which the very
                 last bit of chemical  substance has been released from
                 the surface.  During  this Interval, the film is no
                 longer being applied  but chemical substance is still
                 being released.  Therefore, the mass of chemical
                 substance released 1s decreasing.  Whether the
                 concentration at any  time, t, during this interval is
                 Increasing or 1s decreasing is determined by the air
                 exchange rate.

 (4) tr < t < tu: The mass released 1s  zero.  The concentration is
                 decreasing with time  as ventilation air flows out
                 of the room.

    For the case 1n which the time for evaporation of the chemical
 substance from the film once it 1s applied to the surface is greater
 than, or equal to the time to apply the film to the surface (Case 2), a
 description of the physical situation  during each of the four intervals
 follows:

 (1) t0 < t < ta: Mass of chemical substance released 1s increasing,
                 and concentration at  any time, t, is Increasing during
                 this Interval.  The mass of chemical substance released
                 1s increasing because of the additional  mass being
                 applied to the surface.

 (2) ta < t < tg: Mass of chemical substance released remains constant,
                 and the concentration at anytime, t, continues to
                 increase during this  interval.

 (3) tg < t < tr: The mass of chemical  substance released  is
                 decreasing.

 (4) tr < t < tu: The mass of chemical  substance released  is zero,
                 and the concentration is decreasing with  time.

    By making appropriate substitutions,  one set  of  equations can  be used
 to determine concentrations for both of the cases  described previously.
 For Case 1, let tg equal  t-|  and ta equal  ^2-   For  Case  2»  1et
ta equal t], and tg equal t2-   The following equations  are  used
to determine the concentration of chemical  substance at any time,  t,
during each interval and the average concentration during  each  interval.
                                    77

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 The  average  concentration during the exposure period is determined by
 calculating  a  time-weighted average based on the average concentration
 calculated during each interval.  Note that k = mQ/v.

     (1)   From  t0 to t-\:
           VR[;   i
            Vk  Ik
                                                                    (4-34)
VR
Vk
ft2-
.2
t -
k
e-kt
k2
                       ave
                          -  *
                                                                    (4-35)
    (2)  From t-j < t <
                 C =
                      VR
                       Vk
t, _
                                  -e
                                    -kt
                      (4-36)
                     VR
                      Vk
              ave
                                                                    (4-37)
    (3)  From t2 < t < tr
C = -
VR
 Vk
VR
"vT\ k
                              t    t
                              r '
(4-38)
 ave
e-k(t-V
k
"GNA/I + t _ t \ c •
Vk \k r '/ t2
*
t (
Vk u\ k
*v Ml
r 2 ;J
tr
t2
t, - t, (4-39)
where
    C. = concentration at the time,  tj,  calculated  using
      2  equation (4-36).
                                    78

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     (4)  From tr < t < tu
where

    C.
                                                                     (4-40)
\
-e
-k(t-t
r>
k2
t
u
*r
*r
                                                                    (4-41)
          concentration at the time at which release ends calculated
          using equation (4-38) (mass/volume).
    It must be noted that the time at the beginning of exposure and the
time at the end of exposure can be specified at any time after release
begins.  The only requirement 1s that the time at the beginning of
exposure must occur before the time at the end of exposure.  To delineate
the possible cases that can occur, the convention that t-| corresponds
to ta or tg, whichever Is smaller, and that t2 corresponds to ta
or tg, whichever 1s larger, Is used.  Possible cases for the time at
the Beginning of exposure and the time at the end of exposure 1n relation
to t-j , t2, tr, and tu Include the following:

    • Case 1 :  The time at the beginning of exposure and the time at the
               end of exposure are less than or equal to t-| .  In this
               case, the average concentration during exposure is
               calculated using equation (4-35).   The variable, t^, is
               substituted for t0 and the variable,  te,  is
               substituted for t-| , in equation (4-35).

    • Case 2:  The time at the beginning of exposure is  less than or
               equal to t] , and the time at the end  of  exposure Is
               greater than t-\ , but less than or  equal  to t2-  In
               this case, the average concentration  during exposure is
               the weighted average of average concentrations calculated
               using equations (4-35) and 4-37).   The variable, t^,, is
               substituted for t0 in equation (4-35).  The variable,
               te, is substituted for t2 in equation (4-37).

    • Case 3:  The time at the beginning of exposure is  less than or
               equal to t-j , and the time at the end  of  exposure is
               greater than t2, but less than or  equal  to tr.  In
               this case, the average concentration  during exposure is
               the weighted average of average concentrations calculated
                                    79

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           using equations (4-35), (4-37), and (4-39).  The variable,
           tb, is substituted for t0 in equation (4-35).  The
           variable, te, is substituted for tr in equation (4-39).

• Case 4:  The time at the beginning of exposure is less than or
           equal to t-|, and the time at the end of exposure is
           greater than tr.  In this case, the average
           concentration during exposure is the weighted average of
           average concentrations calculated using equations (4-35),
           (4_37), (4-39), and (4-41).  The variable, tb, is
           substituted for t0 in equation (4-35).  The variable,
           te, is substituted for tu in equation (4-41).

• Case 5:  The time at the beginning of exposure and the time at the
           end of exposure are greater than t-| but less than or
           equal to t£.  In this case, the average concentration
           during exposure is calculated using equation (4-37).  The
           variable, tb, is substituted for t-|, and the variable,
           te, is substituted for t2 in equation (4-37).

• Case 6:  The time at the beginning of exposure is greater than
           t-|, but less than or equal to t2-  The time at the end
           of exposure is greater than t2, but less than or equal
           to tr.  In this case, the average concentration during
           exposure is the weighted average of average concentrations
           calculated using equations (4-37) and (4-39).  The
           variable, tb, is substituted for t] in equation
           (4-37).  The variable, te, is substituted for tr in
           equation (4-39).

• Case 7:  The time at the beginning of exposure is greater than
           t-|, but less than or equal to t2-  The time at the end
           of exposure is greater than tr.  In this case, the
           average concentration during exposure is the weighted
           average of average concentrations calculated using
           equations (4-37),  (4-39),  and (4-41).   The variable, tb,
           is substituted for t-\ in equation (4-37).   The variable,
           te, is substituted for tu in equation (4-41).

• Case 8:  The time at the beginning of exposure and  the time at the
           end of exposure are greater than t2,  but less than or
           equal  to tr.   In this case,  the average concentration
           during exposure is calculated using equation (4-39).  The
           variable, tb, is substituted for t2,  and the variable,
           te, is substituted for tr in equation (4-39).  The
           concentration at the time at the beginning of exposure,
           Ctb,  is substituted for Ct2 in equation (4-39).   Ctb
           is calculated by substituting tb for t in
           equation (4-36).
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     • Case 9;  The time at the beginning of exposure Is greater than
               t2, but less than or equal to tr.  The time at the end
               of exposure 1s greater than tr.  In this case, the
               average concentration during exposure Is the weighted
               average of average concentrations calculated using
               equations (4-39) and (4-41).  The variable, tb, 1s
               substituted for t2 1n equation (4-39).  The variable
               te, 1s substituted for tu 1n equation (4-41).  The
               concentration at the time at the beginning of exposure,
               (^5, 1s substituted for Ct2 1n equation (4-39).  Ctb
               1s calculated by substituting tD for t 1n equation
               (4-36).

     • Case 10: The time at the beginning of exposure and the time at the
               end of exposure are greater than tr.  In this case, the
               average concentration during exposure Is calculated using
               equation (4-41).  The variable, tb, Is substituted for
               tr and the variable, te, 1s substituted for tu 1n
               equation (4-41).  The concentration at the time at the
               beginning of exposure, Ctb, Is substituted for Ctr 1n
               equation (4-41).  Ctr 1s calculated by substituting tb
               for t 1n equation (4-38).

     It must be noted that the physical situations described for the
Intervals comprising these two cases are generally applicable under
environmental conditions considered most likely to occur Indoors.   If,
however, the ventilation air flow rate Is sufficiently high to offset the
rate at which the chemical substance 1s released,  the physical situations
that occur during each Interval will vary from those previously
described.  Additional data are required to determine the combination of
release rate of chemical substance and air exchange rate that would cause
the actual physical situation to deviate.  The derivations of equations
(4-34) through (4-41) are presented 1n detail 1n Appendix E of this
volume.

    Under some circumstances,  the concentrations predicted using these
methods  may exceed the saturation concentration of the chemical  substance
under the environmental  conditions for which It 1s being modeled.   Such
circumstances are most likely to be encountered In scenarios  in which a
large mass of a chemical substance with a relatively low vapor pressure
is available for release from surfaces to which a  film containing  the
chemical substance Is applied.

    A reason for predicted concentrations'  exceeding the saturation
concentration is the underlying assumption of the  methods  presented in
this section that release occurs at a constant rate.   Release at a
constant rate can only be assumed if the kinetics  of mass  transfer are
slow enough that the concentration of the chemical  substance  in  the room
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never reaches a level that 1s high enough to have an appreciable effect
on the rate of release.  If the kinetics of mass transfer are fast enough
that equilibrium 1s approached before the film or coating dries, the rate
of release will decrease exponentially; a numerical method of solution
must Instead be used to provide estimates of concentrations occurring
during exposure.  To Implement a numerical method of solution, a computer
program must be used because of the extensive calculations that must be
carried out.

    In the event that the average concentration predicted using the
equations described previously exceeds the saturation concentration of
the chemical substance 1n any of the four Intervals during exposure, 1t
Is suggested that the assessor substitute the saturation concentration
for the value of the average concentration during that Interval.  The
average concentration during the exposure period Is then determined by
calculating a time-weighted average from the average concentration used
during each applicable Interval.
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                                                            -( i .iX--1* >--«-':i '
              *•	
5.
        EXPOSED  POPULATIONS
     Studies  of  populations  exposed  to  chemical  substances  in  consumer
 products  comprise  three  basic  elements:

     •   Identification  of  exposed  populations
     •   Enumeration  of  exposed  populations
     •   Characterization  of  the population  according  to  age  and/or  sex.

     Identification  of  the exposed populations  relies  on  identification  of
 consumer  products  containing the  chemical  substance  of  concern.  The
 users of  the  products  (i.e., those  who actively  use  and  those who  are
 present during  use) are  the exposed  population.  Once the users are
 identified,  the exposed  population  can be  enumerated  and characterized  by
 the  methods  described  in  Volume 4 of this  series, Methods for Enumerating
 and  Characterizing  Populations Exposed to  Chemical Substances. EPA
 560/5-85-004  (Dixon et al.  1985).   This section will summarize the
 population enumeration report  and indicate how  it applies to consumer
 exposure  assessment.
5.1
         Identification of Exposed Populations
    The steps required for identifying the population exposed to a
chemical substance in consumer products can be summarized as follows:

    1.  Use the data sources discussed in Section 3, or for a new
        chemical substance consult the Premanufacture Notice (PMN), to
        compile a list of the consumer products known to or thought to
        contain the chemical substance of interest.

    2.  Determine whether all or a portion of the consumer product class
        contains the chemical substances; if possible, identify the
        product by brand name to expedite enumeration.

    3.  Identify products obviously intended for use by males or females
        or specific age groups.

    4.  Evaluate each product to determine whether passive exposure is of
        concern.  Consumer product use patterns and chemical release
        patterns will identify the passively exposed population (i.e.,
        family or household members).

5.2      Enumeration of the Exposed Population

    Enumeration of the population exposed to a chemical  substance in
consumer products depends on two factors:  (1) the availability of use
data specific to the products and (2) whether both active and passive
exposure to the chemical substance is involved.  The following subsections
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 briefly  review the sources of available data and the methods for their
 use.   Volume 4 of the series, Methods for Assessing Exposure to Chemical
 Substances presents methods for enumerating populations exposed to
 chemical  substances.

 5.2.1     Enumeration of Exposed Populations via Simmons Market Research
          Bureau Reports

    The  Simmons Market Research Bureau (SMRB) reports are described In
 detail 1n Volume 4 of this series; they are also discussed 1n Section 6.2
 and Appendix D of this volume.  Briefly, SMRB Is a market research
 corporation that collects Information on the buying habits of the U.S.
 population.  SMRB collects this Information for over 1,000 consumer
 products.  For each consumer product, SMRB also collects data on the
 specific  product type (e.g., aerosol rug shampoo versus liquid rug
 shampoo)  as well as the brand name (e.g., Bissell Shampoo versus
 Johnson's Shampoo).  For each type and brand name product, SMRB collects
 Information on the frequency of use (described in greater detail 1n
 Section  6.2 of this report), the total number of buyers as well as the
 number of buyers in each use category, and the demographics (e.g., age,
 race, employment, economic level, geographic location) for the buying
 population.  All this Information 1s presented 1n a series of 29 volumes
 organized according to major product categories.  The 29 volumes of SMRB
 data collected in 1982 have been purchased by EPA-OTS and are Included in
 the Exposure Evaluation Division library.

    Enumeration of populations exposed to a chemical substance in a
 consumer  product 1s, therefore,  a straightforward process with the use of
 the SMRB  reports.  It should be noted, however,  that SMRB presents the
 consumer product data according to the "buyer" and not necessarily
 according to the user (i.e., actively exposed individuals).  It may be
 necessary to adjust the data to reflect potential uses in a household.
 The Investigator must judge on a case-by-case basis how to use the data
 to accurately represent the user or actively exposed population.  Popula-
 tions that are passively exposed as a result of  their proximity to the
 product  both during and following Its active use may also be estimated
 via SMRB data.   For product buyers, SMRB reveals the frequency
 distribution of household size.   For example, SMRB may present 1,000
 female homemakers (I.e., the actively exposed popula- tlon) as purchasers
 of rug shampoo.  For the 1,000 female homemakers, SMRB depicts the number
 of households having 1,  2, 3 or 4, or 5 or more  persons;  these households
would also total 1,000.   To approximate the number of persons living in
 the 1,000 households and potentially passively exposed to the chemical
 substance in rug shampoo, the Investigator can apply the  frequency
 distribution and household size.  Ranges can be  used to accurately
 estimate the exposed population; use of the high end of the ranges
 generates a conservative estimate of exposed persons.
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     The  SMRB  data  are  clearly  Intended  to describe  the market  variability
of  existing products.   Consequently,  the data are generally more
applicable to existing chemicals  and  product formulations currently  on
the  market than  to new chemical substances.  The SMRB data may, however,
prove  useful  to  assessments  of  PMN  substances when  the new chemical  Is
Intended  for  use as a  substitute  for  an existing chemical.  If use
Information Included 1n a  PMN  submlttal 1s sufficiently detailed, the
SMRB data can be used  to predict  the  number of exposed consumers.

     Finally,  as  part of the  Investigation and development of this methods
report,  considerable population data  have already been extracted and
recorded  for  many  of the consumer products under Investigation (as listed
1n Section 1.3).

5.2.2     Enumeration of Exposed Populations via Production and Sales Data

     For  consumer products  not covered by SMRB, the  users can be enumerated
by applying a  number of assumptions and estimation  techniques to economic
data such as  chemical  production  volume, Census of  Manufacturers output,
and  retail sales Information.  To enumerate the users of a consumer
product, the  investigator  must estimate the number  of units of a product
bought by consumers, and then apply such data on use patterns to
determine the  average  number of consumers.  This method can be summarized
in the following steps.

     1. Determine the number of units of the product sold or produced
       annually according  to one of the following options:

       - Consult the Census of Manufacturers (Bureau of the Census 1980b)
         to obtain production in unit quantities.

       - Estimate  the  number of units produced by dividing the amoun't of
         the  chemical  destined for that use by the formulation percent
         and  the total  mass of product per unit.   (Note:   This
         Information must  be derived from the materials balance for the
         chemical  substance of concern.)

     2. Determine the use patterns  for the product.   SMRB reports  provide
       data on frequency of use of consumer products.   Based  on product
       similarities, the investigator can estimate use patterns (e.g.,
       number  of units  used per year).

     3. Calculate the exposed population by dividing  the production volume
       units by the units  used per person per year.

The  results of this approach will  be an estimate,  but  a fairly valid  one;
the parameters used in  the calculation are from reliable  sources.
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5.2.3    Enumeration of Exposed Populations via Chemical-Specific
         Information

    Various sources of chemical-specific Information can also be used to
enumerate exposed populations In lieu of SMRB or production and sales
data.  The Information sources Include the following:

    •  Consumer product associations as listed 1n the Encyclopedia of
       Associations.

    •  Government agencies (e.g., Food and Drug Administration (FDA),
       Consumer Product Safety Commission (CPSC), Bureau of the Census
       (see Section 3.4 for additional Information).

    •  Publications of the Bureau of the Census (e.g., Annual Housing
       Survey. The Statistical Abstract of the United States).

The published literature can also provide valuable information on the
users of consumer products.

5.3      Characterization of Exposed Populations

    Consumer inhalation and ingestion rates and surface areas for
potential dermal contact are a function of the Individual's age and sex.
Accurate estimates of exposure distributions,  therefore, require
characterization of the exposed population according to age and sex.   If
the chemical  substance of concern has special  effects on particular age
classes such as the elderly or children,  further characterization of  the
population 1s required.  Another example  would be a chemical substance
that has been determined to be teratogenic; enumeration of women of
child-bearing age may then be required.

    Data sources for characterizing the exposed population include the
SMRB reports  and the general  age and sex  distribution of the U.S.
population.   Procedures for characterizing exposed populations can be
summarized as follows:

    1.   If the consumer population was enumerated by the use of SMRB
        data,  use the demographic characteristics reported for buyers/
        users to characterize the actively exposed population by age  and
        sex.   Populations enumerated by other  methods can also be
        characterized by consulting the SMRB reports for the product(s)
        most  similar to that  being assessed.
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2.   Consult Volume 4 (Table 12)  of the exposure assessment methods
    series to derive generic age and sex distribution for:

    - Consumer populations under the age of 18 •
    - Passively exposed household members
    - The entire U.S.  population.
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88

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                      O  Jsi*
                     \    i
 6.        EXPOSURE ANALYSIS

     Before  discussing  exposure,  1t  1s necessary to differentiate between
 the  concepts  of  "exposure" and  "dose."  Dose  1s the amount absorbed by
 the  receptor;  exposure refers to the quantity contacting the  receptor and
 available for  absorption.  To be absorbed, a  substance must pass a
 barrier:  the  gastrointestinal  (or  oral) epithelium in the case of
 ingestion exposure, the pulmonary epithelium  for respired substances, or
 the  epidermis  1n the case of dermal contact.  Whether the results of an
 assessment  are to be expressed  as exposure or as absorbed dose depends on
 what use  is to be made of the exposure assessment (see Volume 1 of this
 series).  If  results in terms of absorbed dose are desired, units are
 often expressed as mass of chemical / kilogram of body weight / day.  A
 table of average body  weights,  in kilograms,  for humans is presented in
 Appendix D.  Average body weight values in this table are presented by
 age group.  In actual  practice, experimental data measuring absorption of
 chemical substances is  limited  to a few specific chemical substances and
 conditions.  Although  methods for estimating absorption will be
 discussed,  the emphasis 1n this volume will be on exposure.

    Section 6  is divided into three subsections.  Section 6.1  defines
 exposure pathways and  explains  their relevance to exposure analysis.
 Section 6.2 discusses  methods for calculating exposure.  Current
 knowledge of absorption parameters  is summarized 1n Section 6.3.
 Emphasis is on pathways and scenarios of interest to OTS and on sources
 of chronic  low-level (rather than acute) exposure.   A detailed discussion
 of key factors governing deposition of particles in regions of the
 respiratory tract and  of methods for estimating Inhalation exposure to
 aerosols is presented  1n Appendix A.

 6.1      Exposure Pathways and  Routes

    An exposure route  is the means by which a pollutant in a given medium
 contacts or enters the receptor.  A pathway is the  history of  the flow of
 a pollutant from the source to  receptor, including  qualitative
 description of emission type, transport, medium, and route.   This section
will discuss significant pathways of exposure from  consumer products.
All of these pathways are not covered in this volume.   They are all
 listed here so they can be put  in perspective.

 6.1.1    Inhalation Pathways

    Although Inhalation exposure is probably more significant  in the
ambient and occupational settings,  it may reach levels of grams per  year
 1n the consumer setting.  Consideration  of  odor thresholds  suggests  that
 Inhalation exposures from volatile household chemicals may  reach levels
 of grams per person (Becker et al.  1979).   Reports  of  acute inhalation
toxicity from consumer products  are largely restricted to cases of  carbon
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monoxide poisoning.  Reports of subacute toxidty are fairly common,
e.g., pneumonltls from household pyrethrum use (Carlson and Villaveces
1977), eplstaxls and liver-function abnormalities associated with
consumer use of butyl caulk (NIOSH 1982b), and systemic toxidty from
mothballs (Stricof et al. 1983).  There is also increasing awareness of
the fact that household solvents and pesticides may be associated with
various subcllnical, delayed, or otherwise overlooked chronic effects
such as altered mental states and behavioral manifestations (Levin et al.
1976, Clark 1971).  Finally there is a small, but significant,
subpopulation of hypersensitive persons who display symptoms at substance
concentrations harmless to most people (Sandifer et al. 1972).

    Inhalation pathways are the most complex to analyze and quantify,
since they always involve transport through a medium (air) and associated
emission, fate, and other parameters, which are only occasionally
involved in dermal and ingestlon pathways.

    The physical state of the inhaled substance may be gaseous or aerosol
(I.e., a suspension of liquid or solid particles 1n air).   Significant
pathways can be summarized as follows:

    •  Inhalation of an aerosol resulting from the spray application of a
       product.  The spray may be directed onto the user's person, onto a
       surface to be treated, or into the air itself (as in a room
       deodorant or pesticide space spray).  Exposure may  also result
       from the aerosolizatlon of a poured liquid.

    •  Inhalation of gas evaporating from a liquid surface.  This surface
       may be a film on an object to which the liquid has  been sprayed or
       otherwise applied; the liquid may also be evaporating from a
       container left open during use of the product.

    •  Inhalation of a gas diffusing from a solid matrix,  e.g.,  from
       plastics, dry paint films.

    •  Inhalation of solid particles resulting from (a)  application or
       pouring of dusts or powders;  (b) use or modification of a solid
       product, e.g., by sawing; or (c) re-entrainment during sweeping,
       dusting, etc.

    •  Inhalation of gas or particles resulting from the indoor  or
       outdoor combustion of fuels or other products,  e.g., candles,
       matches, or firelogs.

Methods for all of the above, except the last item and (b) and (c) of the
fourth item, are delineated in this methods report.
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6.1.2     Dermal  Pathways

    Acute poisoning via dermal exposure 1s Infrequent In the consumer
setting,  although cases have been reported, e.g., fatalities from aniline
1n canvas shoes  and laundry markers (Becker et al. 1979).  Local
Irritation and sens1t1zat1on are more commonly reported, e.g., contact
dermatitis from  chemicals 1n paper (Marks 1981) and 1n home dyes (NIOSH
1982a).

    The most common pathways Involve direct contact with a liquid or
powdered  product.  These may be applied to the body directly or contacted
during use or application; the product may also be contacted accidentally
when one  touches the surface to which 1t has been applied.

    Additional dermal exposure pathways Include the following:

    •  Exposure  to aerosol droplets or dust particles suspended 1n the
       air.  The relevant variables are difficult to quantify and Include
       such parameters as motion of the receptor through the room.
    •  Dermal exposure to gases.

    •  Exposure to solid products,
    No scenarios have been developed for the first two pathways listed
above.  Contact with solids can be further broken down as follows:

    •  Exposure to Ingredients leached, diffused, or dissolved out  of a
       solid matrix; e.g., plastldzers In plastic products or pesticides
       1n pressure-treated wood.  Such exposure 1s of particular concern
       when the receptor 1s hypersensitive to the substance;  In such a
       case, the slightest contact with the solid object Itself may cause
       a toxic reaction, even though the absorbed dose may be below the
       limits of accurate quantification.   No scenario has been developed
       for this pathway.

    •  Exposure to chemical substances In  clothing.   These substances may
       be Ingredients of the fabric (e.g., dyes)  or  contaminants (e.g.,
       detergent residues).  This pathway  1s separated from the above
       because opportunities for exposure  to a chemical  used  on fabric
       are much higher.   Fabric used to make clothing Is 1n contact with
       the skin for many hours per day.  Systemic toxldty has been
       reported 1n a series of cases Involving Inadvertent contamination
       of a shipment of  clothing as the result of a  pesticide spill
       (Roueche 1971).

    •  Exposure to fragments or fibers which have become embedded  in the
       skin (e.g., steel wool, glass wool, insulation).   Such exposure is
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       beyond the  scope of this volume, since resulting symptoms are more
       likely due  to physical  irritation than to chemical toxicity per se
       (although subsequent chemical absorption via leaching or
       dissolution  is possible).   In any case, this is not a true dermal
       pathway but  a subcutaneous  injection pathway (see Section 6.1.4).

    •  Exposure from rub-off of surface material which subsequently
       adheres to  the skin as  a powder (e.g., dried ink on printed
       matter; dust from cat box filler, charcoal briquets, or
       insulation).

    •  Contact with dust generated or released during installation,
       machining,  or removal/demolition of a solid product (e.g.,
       wallboard,  roofing, tile, lumber).

    The last two pathways mentioned are considered identical to dust
exposure, and methods are delineated accordingly.

6.1.3    Ingestion  Pathways

    Ingestion is the most significant route of exposure to toxic
substances when incidents of acute toxicity are considered.  Data
compiled by the National Center for Health Statistics (NCHS) suggest that
at least 1,200 people yearly receive oral doses of between 5 and 30 grams
of single chemicals in paints, cleaning agents, disinfectants,  and
petroleum products, based on the number of fatalities reported  and the
toxicities of the  relevant ingredients (Becker et al.  1979).  There are
insufficient data to present typical ranges for cumulative annual
ingestion of individual chemicals resulting from chronic,  rather than
acute, exposure to consumer products.  Exposure resulting from  ingestion
of contaminated food and drinking water will not be considered  in this
volume.  Exposure via food is covered by Volume 8,  and exposure via
drinking water is covered in Volume 5 of the exposure assessment methods
series.

    The following pathways may result in significant exposure:

    •  Deliberate ingestion of a product not meant  to be ingested (see
       below).

    •  Accidental transfer to the mouth of a chemical  that has
       contaminated or settled on the hands or face during use.  There is
       currently no reliable method for assessing such exposure.

    •  Contamination of food in the home,  e.g.,  during preparation,
       storage,  or serving.  In this case,  the subject chemical is  an
       extraneous household pollutant rather than a food ingredient or
       additive;  examples include detergent residues,  plasticizers  in
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        film wrap,  and  Teachable/soluble  constituents  of  vessels, dishes,
        or  silverware.   This  pathway  can  be  significant for chronic
        exposure.   Occasional  cases of acute toxicity  occurring by this
        pathway  have  been  reported, e.g., from  lead  in pottery and in
        cocktail glasses (Bird  et al. 1982).  Exposure may also occur via
        settling onto food  of  airborne particles or  aerosol droplets.
        Such infrequent  events  lack predictable common characteristics and
        do  not lend themselves  to analysis via  standardized scenarios.

    •   Ordinary use  of  objects designed  to be  used  in the mouth.  This
        category is basically  restricted  to infants' toys such as teethers
        and pacifiers and to  such unusual items as athletic mouthguards.
        It may also apply to  dental fillings and prostheses.  In this
        pathway, the  subject  chemical must be leached or dissolved out of
        the solid matrix.

    •   Liquids normally used  in the mouth but not intended to be
        swallowed.  Examples  include toothpaste and  mouthwash; some of
        this may be swallowed,  and some absorbed by  the oral mucosa.

    •   Ingestion as a subset  of inhalation, i.e., swallowing of inhaled
        particles too large to  be respired.

Methods are delineated  in this volume for the last  three pathways.

    Methods for estimating exposure from deliberate Ingestion of products
will not be delineated  in this volume, despite the  frequency and
seriousness of clinical poisoning via this pathway, for several reasons.
Deliberate ingestion of inedible substances may be  either purposeful
(e.g.,  pica, suicide) or not  (e.g., product mistaken for something
edible).  Exposure may  involve the ingestion of a chemical  substance per
se, usually in liquid form, or the swallowing of a  solid object,  e.g.,  a
pill bottle desiccant (Muhletaler et al. 1980).  The swallowing of
objects is essentially a product safety consideration and is beyond the
scope of OTS responsibility.   (However, it should be noted  that the body
may absorb toxic substances released from the ingested object during
gastrointestinal retention (Litovitz 1983).)   Deliberate Ingestion of
liquids will not be considered.  Quantifying acute  threats  requires a
different approach from that used to predict isolated incidents of
negligence or misuse.

    It  should be noted that some unusual forms of exposure  may fall  into
more than one setting.  An example is a reported case of drinking water
contamination from phenol  originating from the tank liner of a solar
water heater (Trincher and Rissing 1983).  Volume 5 of this series
describes the framework for calculating exposure to chemicals
contaminating drinking water, and presents data on  such required  input
parameters as daily drinking water intake.  However, the water heater in
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question  is purchased and  operated by consumers; therefore, other
parameters (e.g., exposed  population, chemical  release, and ultimate
concentration) must be calculated by methods discussed 1n this volume.
Such  "hybrid" exposures are  relatively uncommon and should be handled on
a case-by-case basis.

6.1.4     Other Pathways

    Chemicals may be absorbed from consumer products via routes other
than the  three most common ones discussed above.  No scenarios will be
developed for these; however, they will be listed for completeness.
Three examples that may occasionally be significant Include:  (1) direct
ocular absorption, e.g., of  pesticide vapors (Morgan and Roan 1974);
(2) use of rectal and vaginal suppositories or devices; and (3) Injection
(subcutaneous or other).

    The last two categories  are restricted to use of medical products, at
least under ordinary circumstances, and are therefore beyond the
jurisdiction of EPA.  Exceptions Include penetration of the skin by
fibers (e.g., asbestos) and  trauma (e.g., the accidental  Injection Into
the hand  via spray-gun of  lead-containing paint) (LHIs et al. 1981).
Such Incidents are unpredictable and not amenable to" quantification.

    Medical Implants and prostheses are also excluded from
consideration.  Note that contact with oral mucosa Is Included under
"Ingestlon" and with the upper respiratory epithelium under "Inhalation."

6.2       Exposure Calculation

    This  section presents methods and data needed to estimate exposure.
Frequency of use 1s a parameter required to estimate annual  exposure to
consumer products for Inhalation, dermal, and Ingestion pathways.
Section 6.2.1  provides Information to aid the assessor in determining
frequency of use.  Methods for estimating inhalation exposure are found
1n Section 6.2.2.  Section 6.2.3 presents methods for estimating dermal
exposure, while Section 6.2.4 cites methods for estimating ingestion
exposure.  Methods for estimating Inhalation exposure to  particulates
discharged from consumer products are presented in Appendix  A.

6.2.1     Frequency of Use

    Market research reports are a very useful source of data on product
use frequency.  One readily available series of market research reports
is the Simmons Market Research Bureau (SMRB)  reports.   SMRB  is  a market
research corporation that collects information  on the buying habits  of
the population through questionnaires administered to a nationwide panel
of consumers.   This study,  The Simmons Media and Market Report  (SMRB
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 1982),  1s  designed  to  serve  retailers, advertising agencies, and  the
 media by providing  up-to-date,  comprehensive  Information  on current and
 potential  sales markets  for  consumer products.

    Appendix  B lists products covered  In SMRB by volume.   For each
 product category, section  IB of SMRB usually  Indicates how many
 households buy or use  the  product.  If the product requires Installation,
 SMRB often Indicates the number of persons Installing It  themselves.
 Products are  often  broken  down  by type, e.g., aerosol, liquid, powder.

    Populations are reported for heavy, medium, and light  use categories
 (H, M, L).  These are  defined separately for each product, and a  table Is
 provided.  This permits calculation of a distribution of  frequency of use.

    In many Instances, SMRB  reports the number of containers, cans, or
 bottles purchased per  time period Instead of the number of uses.  To
 translate these data Into  uses per year, 1t 1s necessary  to know  how much
 product 1s consumed per use, and how much 1s contained In  a single
 container.  This Information can be obtained from a number of sources,
 Including product labels,  or contact with trade associations, Industry,
 users' (e.g., hobby) associations, and government agencies such as CPSC
 or FDA.  These same sources  can also be consulted when a particular
 product 1s not listed  1n   SMRB.

 6.2.2  Inhalation Exposure

    Inhalation exposure 1s defined for the purpose of this report as the
 quantity of a chemical substance that 1s taken Into the body via the
 Inhalation route during a given period of time.   Exposure  Is to be
 distinguished from absorbed dose, which refers to the quantity of
 chemical absorbed across biological  membranes as a result  of exposure.
 Background Information on the Inhalation route of exposure Is provided
 In (1), followed by a discussion of  the method used to estimate
 Inhalation exposure to gases and vapors In (2).

         (1)   Background.  Chemical  substances present In ambient air  as
gases or vapors may be Inhaled, thus contributing to exposure via the
 lungs.  Although a significant fraction of the Inhaled chemical  may be
 exhaled, this fraction 1s chemical-specific and  thus not easily
predicted.   For this reason, exposure estimates  for gases and vapors are
 based on the entire quantity of Inhaled chemical.  Aerosols (I.e.,
 suspensions of small liquid or solid particles In air),  however,  are
 subject to differential deposition 1n various regions  of the respiratory
tract.  Particle deposition patterns can be roughly predicted based on
 knowledge of  the particle size distribution of Inhaled aerosols.
 Particle sizes are usually measured  as  particle  aerodynamic diameter,
defined as  the diameter (In \im)  of a sphere of unit density having the
                                    95

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 same  terminal  velocity as  the  particle  1n question, regardless of Its
 shape and  density  (Marple  and  Rubow 1980).  Exposure calculations for
 Inhaled  aerosols can  be  refined by Incorporating Information on particle
 size  distribution  and knowledge of the  relationship between particle size
 and respiratory tract deposition patterns.  A detailed discussion of key
 factors  governing  deposition of particles and of methods for estimating
 Inhalation  exposure as a function of regional deposition of particles In
 the respiratory tract 1s presented 1n Appendix A of this volume.

         (2)   Exposure Calculation.  Assessment of Inhalation exposure to
 consumer products  Involves finding a simple or complex solution to the
 following  equation:
                              = i
                                  C(t)dt
                                                         (6-1)
where
          t
       C(t)
        = Inhalation exposure (mass/time)
        = Inhalation rate (volume/time)
        = duration of exposure (time)
        = concentration of chemical In air as a function of time
          (mass/volume).
In practice, the algorithm used to calculate Inhalation exposure Is
usually an Integrated and simplified version of equation (6-1), often
Incorporating simplifying assumptions about the change 1n concentration
with time.  (See Section 4 for a detailed discussion of methods for
calculating concentration.)  In many cases, exposures can be calculated
using an average concentration for a given period of time;  exposures from
several such consecutive time periods can be summed to estimate total
Inhalation exposure to a given product.  The simplified version of
equation (6-1) 1s presented below.
                          IHX = IR x DU x FQ x CN
                                                              (6-2)
where
       IHX = Inhalation exposure (mg/yr)
        IR = Inhalation rate (m3/hr)
        DU = duration of exposure event (hours)
        FQ = frequency of exposure (events per year)
           = average Indoor air concentration of a given constituent
             (mg/m3).
    CN
The variables of equation (6-2) are determined as follows:
m3/h
r.
 (a)  Inhalation rate.  Inhalation rate (IR)  Is  expressed  In
The factors that have the most Influence on human lung
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ventilation  rates  Include tidal volume of the lung and breathing
frequency.   Tidal  volume (I.e., volume of gas Inhaled or exhaled per
respiration  cycle) 1s dependent upon Individual characteristics,
Including size, age, and sex.  The breathing frequency 1s based on the
degree of exertion, which can be related to general types of activities.

    Data on  ventilation rates as a function of these factors are provided
1n Development of  Statistical Distributions or Ranges of Standard Factors
Used 1n Exposure Assessments (Anderson et al. 1984).  The data presented
Include ventilation values for adult males, adult females, and children
during resting and during light, moderate, and heavy exertion.
Representative values for each activity category are presented In Table
25.  Values  of Inhalation rates presented 1n this table represent the
midpoint of  ranges of values reported for each activity level In Anderson
et al. (1984).  Resting 1s characterized by activities such as watching
television,  reading, or sleeping.  Light activity Includes meal cleanup;
care of laundry and clothes; domestic work and other miscellaneous
household chores;  attending to personal needs and care; photography;
hobbles; and conducting minor Indoor repairs and home Improvements.
Heavy activity Includes heavy Indoor cleanup (e.g., scrubbing surfaces),
and performing major Indoor repairs and alterations (e.g., remodeling).
Maximal activity consists of vigorous physical exercise,  such as weight
lifting, dancing,  or riding an exercise bike.  Light activity is the
level that occurs most frequently during the use of consumer products.

    Additional factors that Influence inhalation rates include altitude
and body temperature.  The respiratory rate increases 5 to 6 breaths  per
minute per each degree Celsius rise in body temperature (ICRP 1974);
likewise, Inhalation rate increases with increasing altitude.  Knowledge
of the effect of these parameters on inhalation is not likely to enhance
the quality of most exposure assessments,  however.

         (b)  Duration of exposure.  Inhalation exposure  to many consumer
products can be divided into several stages, each of which may have a
different duration.  For example,  exposure to an aerosol  product during
active use of that product may last for only seconds or minutes.   Passive
exposure to direct release of that  product may last for hours.   And,  if
the aerosol  product is a coating (e.g., paint)  applied to a surface
indoors, a third Inhalation exposure stage,  consisting of the period
during which the chemical  release rate 1s  controlled by diffusion  from
the solid coating, may last for weeks or months.   Duration of exposure
during application of coatings to surfaces can be estimated from
information on labor production (e.g.,  surface area covered per unit  of
time) and on the surface area to be covered.  For some exposure scenarios
involving the use of pressurized aerosol  products,  in the absence  of
better Information, it may be necessary to assume that duration of
exposure is  equal to the duration of active  release.   For aerosol
products in which direct release occurs intermittently over the course of
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       Table 25.  Summary of Human Inhalation Rates for Men, Women,
                  and Children by Activity Level  (m3/hour)a
                   Resting5
lightc
Moderated
Heavy6
Adult male
Adult female
Average adult^
Child, age 6
Child, age 10
0.6
0.6
0.6
0.4
0.4
1.3
1.3
1.3
1.4
1.7
2.8
2.4
2.6
2.1
3.3
7.1
4.9
6.0
2.4
4.2
aValues of inhalation rates for males, females, and children presented
 in this table represent the midpoint of ranges of values reported for
 each activity level in Anderson et al.  (1984).

''includes watching television, reading,  and sleeping.

clncludes most domestic work, attending to personal needs and care,
 hobbies, and conducting minor indoor repairs and home improvements.

^Includes heavy indoor cleanup, performance of major indoor repairs
 and alterations, and climbing stairs.

elncludes vigorous physical exercise and climbing stairs carrying a
 load.

^Derived by taking the mean of the adult male and adult female values
 for each activity level.  A representative 24-hour breathing rate for
 an average adult is 1.1.  This value is based on the assumption that
 the average adult spends 93.2 percent of the time at the light/resting
 level of activity, 5.8 percent at a moderate level of activity, and  0.9
 percent at a heavy level of activity.  Values for the percent of time
 spent at each activity level are from Methods for Assessing Exposure to
 Chemical Substances in the Ambient Environment, Volume 2 of Methods  for
 Assessing Exposure to Chemical Substances.
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 several  minutes,  professional  judgment must be  used to estimate  the
 duration of  active  use.

    Most long-term  passive  Inhalation scenarios Involve exposure to a
 chemical  substance  being  released from a  solid  matrix.  One possible
 approach for estimating duration of passive Inhalation exposure  to
 chemical  substances  released from solid matrices 1s to assume that
 release  of a chemical  substance will occur continuously at a constant
 rate  throughout the  lifetime of a product.  One can then also assume that
 the duration of exposure  1s equivalent to the lifetime of the product.
 Information  regarding  product  lifetimes can sometimes be obtained from
 the Industry that manufactures the product or the trade association that
 represents the Industry that manufactures the product.

          (c)  Frequency of  exposure.  Frequency of exposure, expressed 1n
 number of exposure events per  year, 1s discussed 1n Section 6.2.1.

          (d)  Concentration of the chemical substance 1n indoor air.  The
 concentration of chemical substance 1n Indoor air 1s expressed 1n units
 of mass  of chemical  substance  per cubic meter of air.   The method for
 calculating  the concentration  of a chemical substance in indoor air is
 determined by whether  the chemical substance 1s released instantaneously,
 continuously, or 1n  a  time-dependent manner.   Examples of Instantaneous
 releases  Include releases of volatile chemical substances from spills of
 products and short-term releases of chemical  substances from aerosol
 containers.  Examples  of continuous releases  Include volatilization of
 chemical  substances  from liquids spilled instantaneously and migration of
 chemical substances  from solids, such as dry  paint films and plastics.
 Time-dependent releases include volatilization of chemical  substances
 from films or coatings applied to surfaces.  Usually products  such as
 coatings are not applied Instantaneously to surfaces.   As a result,  a
method is needed to account for the fact that a chemical  substance may
 have almost  completely volatilized from the portion of the  surface coated
at the beginning of the period of application, while it has only begun to
 volatilize from the portion of the surface coated at the end of  the
period of application.  Such differences 1n the change of concentration
with time are accounted for in the equations  used to calculate Indoor air
concentrations of chemical substances  as a result of time-dependent
 releases.  Equations for calculating concentrations of chemical
 substances 1n Indoor air as a result of  instantaneous, continuous,  and
time-dependent releases are presented  in detail  in  Section  4.4.

    Generally, the equations for calculating  the average  concentration  of
chemical substance 1n air for a given  set of  exposure  conditions are used
to estimate the value of CN to be used  in the  equations  to  estimate
 inhalation exposure.
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 6.2.3   Dermal  Exposure

     Despite  the  relative  simplicity  of  most  dermal exposure calculations,
 dermal  exposure  presents  some  conceptual  difficulties that are not
 associated with  Inhalation  or  1ngest1on exposure.  Exposure has been
 defined  earlier  as  the  amount  of  substance contacting the receptor and
 available for  absorption.   Absorption occurs when the substance crosses a
 physical barrier to penetrate  the tissues of the receptor.  "Contact"
 merely  Implies that the substance has touched the body of the receptor.
 "Availability" Indicates  that  the substance  has reached (but not crossed)
 the  absorbtlve barrier.   In  the case of Inhalation and 1ngest1on, the
 substance 1s taken  Into a body cavity (mouth, lungs) prior to
 absorption.  Therefore, the  substance 1s made available by swallowing or
 Inhaling, and  the quantity  to which  the receptor 1s exposed is equivalent
 to the quantity  inhaled or  swallowed.   In the case of dermal exposure,
 the  substance  contacts  only  the outer surface (skin) of the receptor and
 1s not taken into the body  until  it  has  penetrated the skin (I.e., after
 it has been absorbed).  In  addition, the substance may contact the skin
 but  be removed before 1t can be absorbed.  This makes it difficult to
 define "exposure" when  the  receptor  1s  1n contact with large ambient
 volumes  of liquids  or gases  or with a small portion of a large solid
 surface.

     The  sections that follow delineate  methods that can be used to
 estimate dermal  exposure that has  occurred via three pathways:
 (1)  exposure to  a film  of liquid  deposited on the skin;  (2)  exposure to
 dusts and powders deposited  on the skin; and (3) exposure of skin to
 chemical substances  contained 1n  or adhering to solid matrices.   A method
 for  assessing exposure  during immersion of skin in liquids is  not
 presented.   A method for estimating absorbepL4fise resulting  from this
 pathway, however, is delineated in Sect 10(1^6.3/2^  The major problem with
 attempting to assess exposure during 1mmersnrrr"o~f skin in liquids 1s that
 the  portion of the  entire mass of  the chemical  substance in  the solution
 that 1s 1n contact with the  receptor 1s not known.   Obviously,  the skin
 of the receptor  1s  not  in contact with  the entire volume of  the
 solution.  A method  for determining the exact thickness  of the  film,  or
 solution, in contact with the skin during the period  of  exposure,
however, cannot  be  readily determined because the physical  state  of  the
 solution in contact with the skin  1s exactly the same as  the physical
 state of the solution that is not  in contact with the skin.   Any  attempt
to assess exposure  for this pathway without taking  into  consideration
parameters  needed to estimate absorbed dose 1s  not  very  meaningful.

     (1)  Exposure to a Film of Liquid Deposited  on  the Skin.  Most
 significant,  quantifiable dermal  consumer exposure  scenarios  involve
 liquid films  on  the  skin.   Exposure is generally expressed as mass  per
year.  For  each  use of the product, the assessor determines  the mass  of
 liquid deposited  on the skin by multiplying (1)  the  estimated volume  of
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liquid deposited by (2) the estimated concentration of the subject
chemical substance 1n the liquid deposited on the skin.  This, multiplied
by the number of annual exposures, yields total mass per year.  Since
exposure is by direct physical contact, there are no fate or transport-
related parameters involved.

    The product obtained by multiplying (1) the area of skin likely to be
exposed during ordinary use by (2) the film thickness is an estimate of
the volume of liquid deposited on the skin.  The film thickness of a
liquid can be determined using the following equation:

     Film thickness (cm) = amount of liquid retained on skin (mg/cm2)
                           density of liquid (g/cm3) x 1000 (mg/g)

Experimentally determined values of the amount of liquid retained on
hands are presented 1n Methods for Estimating the Retention of Chemical
Liquids on Hands. Volume 13 of Methods for Assessing Exposure to Chemical
Substances (Versar 1984a).  In this study, the retention of selected
liquids on the hands of human volunteers was measured under five
conditions of exposure:  (1) uptake by dry skin (initial uptake);
(2) uptake by skin previously exposed to the liquid-and still wet
(secondary uptake); (3) uptake from handling a rag; (4) uptake from spill
cleanup;  and (5) uptake from Immersion of a hand in a liquid.

    Initial uptake, secondary uptake, and uptake from handling a rag all
Involved  contact with a cloth saturated with the liquid.  The method for
determining liquid retained on the hands for each of the five
experimental conditions is as follows:

    •  Initial uptake - A cloth saturated with liquid was  rubbed over the
       front and back of both clean,  dry hands for the first time during
       an exposure event.

    •  Secondary uptake - As much as  possible of the liquid that adhered
       to the skin during Initial uptake was removed using a clean
       cloth.   A cloth saturated with the liquid was then  rubbed over the
       front and back of both hands for the second time during an
       exposure event.

    •  Uptake from handling a cloth - A cloth saturated with liquid  was
       rubbed over the palms of both  hands for the first time during an
       exposure event in a manner simulating handling of a wet cloth.

    •  Uptake from immersion - An Individual  Immersed one  hand in a
       container of liquid,  removed the hand,  then allowed the liquid  to
       drip from the hand  back Into the container for 30 seconds (one
       minute for cooking  oil).
                                   101

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     •   Uptake  from  spill  cleanup  -  An  individual  used a clean cloth to
        wipe  up 50 milimters  (ml)  of  liquid  poured  onto a plastic
        laminate  countertop.

     For each exposure  condition,  the quantity of  liquid retained on the
 hands was  determined:  (1)  immediately  following the  exposure condition;
 (2)  after  a  partial wipe;  and  (3) after a  full wipe  (except in the case
 of  uptake  by Immersion and uptake from spill  cleanup).  A partial wipe
 refers  to  a  light,  quick  wipe  with  a clean cloth.  A full wipe refers to
 a thorough,  complete wipe with a  clean cloth.

     The method for  determining the  quantity of liquid remaining on the
 exposed area of  the hands, presented 1n mg/cm2, was the same for all
 tests Involving  use of a  cloth saturated with liquid.  The quantity of
 liquid  remaining on the exposed area of the hands immediately following
 exposure (the  Initial quantity) was determined by subtracting the weight
 of  the  cloth saturated with liquid  after exposure from the weight of the
 cloth saturated with liquid before  exposure, and dividing this difference
 by  the  exposed skin surface area.   The quantity of liquid remaining on
 the  exposed area of the hands  after a  partial wipe was determined by
 subtracting the quantity  removed by a  partial wipe from the initial
 quantity, and dividing this difference by the exposed surface area.  The
 quantity remaining after  a full wipe was determined by subtracting the
 quotient of the quantity  removed by the full wipe divided by the exposed
 surface area from the quantity remaining after a partial wipe.

     The quantity of liquid remaining on the exposed area of the hands
 immediately following immersion and spill  cleanup was determined by,
 first,  summing the quantities  of liquid removed by a partial  wipe and  a
 full wipe.   This sum was  then  divided by the exposed surface area.   The
 resulting quotient was added to the value for quantity in mg/cm2
 remaining on the skin after a  full wipe as determined in the initial
 uptake  test.  To give an estimate of the total quantity of  liquid
deposited by immersion or spill cleanup,  the quantity of liquid remaining
after a partial wipe was determined by dividing the quantity  removed  by a
full wipe by the exposed surface area and  adding this quotient  to the
value for quantity remaining on the skin after a full wipe  as  determined
 in the  initial  uptake test.

     Initially six liquids were selected in this  study to represent  a
broad range of  kinematic viscosities.   The liquids used were  (1)  mineral
oil, (2) cooking oil, (3) water-soluble oil (bath  oil),  (4)  oil/water
emulsion (50:50, water:water-soluble oil),  (5) water, and
 (6)  water/ethanol (50:50).  (Efforts to include additional  liquids  in
this study  are  on-going).  Table 26 presents  values  of film thickness  for
these six liquids under each of the five exposure  conditions  immediately
following exposure,  after a partial  wipe,  and after  a full  wipe.   The
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                        Table 26.  Film Thickness Values of Selected Liquids
                                   Under Various Experimental Conditions (10-3
                          Mineral       Cooking     Bath       Oil/                  Water/
                            oil           oil        oil       water       Water     ethanol
Initial uptake

Initial film thickness
 of liquid on hands           1.62          1.63      1.99       2.03        2.34       3.25
                             •' ;"          -3.^     /."'-
Film thickness after
 partial wipe                 0.69          0.68      0.76       1.55        1.83       2.93
                              . L-.i          -  .  ,;1    /,.;;•
Film thickness after
 full wipe                    0.21          0.16      0.21       1.38        1.97       3.12

Secondary uptake

Initial film thickness
 of liquids on hands          1.43          1.51      1.80       1.60        2.05       2.95
                            I. •           I •         ! •  r --
Film thickness after
 partial wipe                0.47          0.53      0.51       1.19        1.39       2.67

Film thickness after
 full  wipe                   0.14          0.11      0.12       0.92        1.32       2.60

Uptake from handling
a rag

Initial film thickness
 of liquid on palms           1.64          1.50      2.04       1.88        2.10       4.17

Film thickness after
 partial wipe                0.44          0.34      0.53       1.21        1.48       3.70

Film thickness after
 full  wipe                   0.13          0.01      0.21       0.96        1.37        3.58
                                                  103

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                                       Table 26.  (Continued)
                          Mineral       Cooking     Bath       Oil/
                            oil           oil        oil       water
                                                        Water/
                                              Water     ethanol
Uptake from immersion

Estimated initial film
 thickness of liquid on
 hand

Estimated film thickness
 of liquid remaining
 after partial wipe

Uptake from spill
cleanup

Estimated initial film
 thickness of liquid on
 hand

Estimated film thickness
 of liquid remaining
 after partial wipe
15.88
 1.49
2- •  -'
 1.23
 0.55
11.28     12.06       9.81

 G  '.'      '   '  >


 1.59      1.51       2.42
 0.73      0.89        1.19
 0.51       0.48        1.36
4.99       6.55
2.14       2.93
Source:  Versar (1984a)
                                                  104

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 values  for  film  thickness  presented  1n  this  table were derived from the
 experimental data  on  (1) amounts  of  liquid  retained on the hands and (2)
 densities of liquids  from  the  study  to  assess  exposure resulting from
 retention of chemical  liquids  on  hands  (Versar  1985a).

    The volume of  liquid deposited on the skin  cannot be estimated
 reliably by calculations Involving quantity  of  product consumed per use
 except  1n cases  when  the total amount consumed  per use 1s applied
 directly to the  skin  (e.g., cosmetic products).  For example, exposure to
 substances  spilled on  the  skin has occasionally been estimated by
 predicting  (arbitrarily) the amount  likely to  be spilled (e.g., 1 ml) or
 the percent of product likely  to  be  spilled  (e.g., 10 percent).  This may
 yield an unreaHstlcally high  level  of  exposure, since measured film
 thicknesses of liquids on  the  skin are  on the  order of magnitude of
 10~3 cm (Versar  1984a).  Therefore,  most of  a  quantity of liquid
 spilled on the skin would  probably drip off  Immediately and not
 constitute genuine exposure.

    An estimate  of the concentration of the  subject chemical substance on
 the skin 1s derived by multiplying together: (1) the weight fraction (WF)
 of the chemical  substance  1n the  product, (2) the density (DSY) of the
 formulation, and (3) the dilution factor (OIL), or fraction of
 formulation present as used by the consumer  during the exposure event.

    The basic equation for estimating annual dermal exposure via a liquid
 film 1s as follows:
                   DEX = WF x DSY x OIL x T x AV x FQ             (6-3)

where

       DEX = annual dermal exposure (mg/yr)
        WF = weight fraction of chemical substance 1n product (unitless)
       DSY = density of formulation (mg/cm3)
       OIL = dilution fraction (unitless)
         T = film thickness of liquid on the skin surface (cm)
        AV = skin surface area exposed per event (cm2/event)
        FQ = frequency of events per year (events/yr).


    The variables of equation (6-3) are determined as  follows:

    •  The weight fraction (WF) of a chemical substance in a  formulation
       can sometimes be obtained from the product label.   Other sources
       of information that may be needed to determine  the weight fraction
       of chemical substances in products are discussed in Section  3.  A
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generic approach  for determining the weight fraction of a chemical
substance based on knowledge of its function in a product can also
be used.  This generic approach and values for the weight fraction
of functional components in select consumer products are presented
in Section 3.

The density (DSY) of a formulation can sometimes be obtained from
the product label.  It can also be easily determined experimentally
if the product is available.  Table 11 of Section 3 presents
experimentally determined values for the density of select
consumer products.  For products not included in Table 11 it is
suggested that the density of the chemical substance making up the
largest weight fraction in the formulation be used as a default
value for the density of the product.  Densities for specific
chemical substances can be obtained from references listed in
Table 9 of Section 2.

The dilution fraction (DIL) is the quotient obtained from dividing
the mass of product by the mass of substance in which this mass of
product is diluted.  The dilution fraction can sometimes be
determined from information on the product label.  Products that
are used undiluted are assigned a value of 1.0 for dilution
fraction.

The film thickness of a liquid on the skin (T)  is the quotient
obtained by dividing the mass of liquid retained per square
centimeter (cm2)  of skin surface by the density of the liquid as
used by the consumer.  Table 26 presents values for film thickness
of selected liquids under various experimental  conditions based on
data from Methods for Estimating the Retention  of Chemical  Liquids
on Hands (Versar 1984a).   For assessing dermal  exposure to liquids
listed in Table 26, the values presented in this table for film
thickness can be used without adjustment.   To assess dermal
exposure to liquids that are not listed in this table,  one can use
data for the liquid that most closely resembles the liquid  for
which one is trying to assess exposure.  Two physical  properties
that can be used  to compare liquids are kinematic viscosity and
density.  Values  for kinematic viscosity and density can be
obtained from references  listed in Table 9 of  Section  2.   The
experimentally determined values for density and kinematic
viscosity for the six liquids used in the  study to assess exposure
from retention of liquids on hands are presented in Table 27.
However, the error from using default values as values  of film
thickness for liquids not listed in Table  26 may be considerable.
In the study to assess exposure from retention  of liquids on
hands, the relationship between kinematic  viscosity and mass  of
liquid retained per cm2 of  skin was examined.   Although liquid
                             106

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        Table 27.   Experimentally Determined Values for Density and
                  Kinematic Viscosity of Six Selected  Liquids
Liquid
Mineral oil
Cooking oil
Bath oil
Bath oil /water
Water
Water/ethanol
Density (g/cm^)
0.8720
0.9161
0.8660
0.9357
0.9989
0.9297
Kinematic viscosity (cSta)
183.0
65.4
67.2
4.19
1.02
2.55
Source:  Versar (1984a).

acentistokes.
                                   •107

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        retention was found to  Increase with kinematic viscosity, the data
        did not  support a  functional relationship between these two
        parameters.  Additional  liquids must be examined to determine
        whether  a functional relationship exists between these two
        parameters.

     •   The exposed  skin surface area (AV) can be ascertained from
        judgment as  to regions  of the body likely to be exposed during use
        of the product and from generic values for skin surface area
        presented in Table 28.

     (2)  Exposure to Dusts and  Powders Deposited on the Skin.  Exposure
to dusts and powders is similar to exposure to liquid films, since it
involves the deposition of a limited, quantifiable amount of product on
the  skin.  The parameter, dust  adherence (DA), however, replaces the film
thickness (T) and density (DSY) parameters required in equation (6-3) for
estimating dermal exposure to  liquid films.  The dust adherence parameter
1s expressed in units of mass  per unit of skin surface area and unlike
liquid  films, does not require  a density factor to convert volume to mass.

     The basic equation for estimating annual dermal exposure to dusts and
powders deposited on skin is as follows:
                         DEX = WF x AV x DA x FQ
                                                       (6-4)
    DEX
     WF
     AV
     DA
     FQ
annual dermal exposure (mg/year)
weight fraction of chemical substance in product (unitless)
skin surface area exposed per event (cm2/event)
dust adherence (mg/cm2)
frequency of events per year (events/year).
Methods for determining the variables, WF, AV, and FQ,  were delineated in
Section 6.2.3(1).  Data on dust adherence to skin (DA)  are limited.  The
following experimental values for dust adherence were reported by the
Toxic Substances Control Commission of the State of Michigan (Harger
1979):

    •  Vacuum cleaner dust sieved through an 80-mesh screen adheres to
       human hands at 3.44 mg/cm2.

    •  Dust of the clay mineral kaolin adheres to hands at 2.77 mg/cm2.

    •  Commercial potting soil adheres to hands at 1.45 mg/cm2.
                                    108

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                  Table  28.   Surface Area  of  Body  Regions3
      Body  region
 Percent of
total surface
    area
      Generic
surface area (crn^)
                                 Male   Female
                  Male   Female   Average
                                   adult
Total adults0
Head and neck
Faced
Neckd
Scalpd
Upper extremities6
Arms (both, excluding hands)
Upper arms^
Forearms^
Hands
Outstretched palm and fingersS
Lower extremities"
Legs
Thighs
Lower legs
Feet
Trunk
Total, 3-6 year-old child0
Total, 6-9 year-old child0
Total, 9-12 year-old child0
100
7.8
2.6
2.6
2.6
18.8
14.1
7.4
5.9
5.2
2.6
37.5
31.2
18.4
12.8
7.0
35.9
100
100
100
100
7.1
2.4
2.4
2.4
17.9
14.0
7.4
5. -9
5.1
2.6
40.3
32.4
19.5
12.8
6.5
34.8
100
100
100
19,400
1,180
390
390
390
3,190
2,280
1,430
1,140
840
420
6,360
5,050
1,980
2,070
1,120
5,690
7,280
9,310
11,600
16,900
1,100
370
370
370
2,760
2,100
1,250
1,000
750
375
6,260
4,880
2,950
1,940
975
5,420
7,110
9,190
11,600
18,150
1,140
380
380
380
2,975
2,190
1,340
1,070
795
400
6,310
4,970
2,470
2,005
1,050
5,555
7,200
9,250
11,600
aUnless otherwise noted, values for surface area presented in this table
 are mean values reported in Anderson et al. (1984).

^Values presented in this table for average surface area are the average
 of values reported or derived for males and females.

°The values for surface area of the total body presented in this table
 for adults and children are based on values of surface area, reported for
 the 50th percentile group in Anderson et al.  (1984).

'•'values presented for surface area of this body region are based on the
 assumption that this body region comprises one-third of the surface area
 of the head and neck.

elncludes arms and hands.

^Anderson et al. (1984) do not report values for females for these body
 regions; values presented were obtained by applying the percentage of
 total body surface area reported for males for these body regions to the
 total body surface area value for females presented in this table.

SA value of one-half the surface area of the hands is assumed.

"includes legs and feet.
                                    109

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The conditions of the experiment were not reported.  Since the research
was performed to support predictions of occupational exposure to the
chemical, 4, 4' - methylenebis (2-chloroaniline) (MBOCA), and since
occupational contact 1s likely to yield maximum saturation of the skin,
it 1s assumed that the experimental conditions were designed to encourage
maximum dust adherence (Versar 1982).  It is not known, however, which
physical or chemical properties of a powdered substance determine the
extent of its adherence to skin; therefore, it 1s not possible to predict
the extent to which the three substances tested may represent commonly
encountered household products (e.g., powdered detergent).

    Until more data become available, the value for vacuum cleaner dust
can be used as an upper limit.  Substances that are UpophiHc or
surfactant, or that tend to clump in the presence of skin moisture,  may
adhere to a greater extent.  However, since maximum adherence is probably
rare 1n most household exposure scenarios, the value for vacuum cleaner
dust probably represents dust adherence under reasonable worst case
conditions.

    (3)  Exposure of Skin to Chemical Substances Contained in or Adhering
to Solid Matrices.   The primary application for assessing exposure of
skin to chemical substances contained 1n or adhering to solid matrices is
the assessment of dermal exposure to substances in clothing.   Exposure to
substances in clothing can be divided Into substances contaminating
clothing, such as detergent residues, and substances that are ingredients
of clothing, such as dyes.  In the case of both dyes and residues,  the
fraction transferred to the skin must be known to accurately  assess
exposure.  The tendency for chemical substances to transfer to skin
varies with the quantity of residue or dye on the fabric, the specific
chemical substance  being transferred from the fabric to the skin,
physical and chemical properties of the skin surface being contacted, and
duration of contact of skin with the substance being transferred.   No
experimental data regarding transfer of residues or dyes to skin have
been found.  As a result of a lack of data for this parameter,  arbitrary
values for percent  transfer during exposure must be used.

    In an assessment of consumer exposure to sodium LAS (Linear
alkanesulfonate surfactant) in detergent products,  Procter and  Gamble
(1981  as cited in JRB 1982b)  calculated dermal  absorption of  sodium  LAS
in detergent residues on clothing using an arbitrary transfer factor for
detergent residue of ten percent (.10)  (JRB 1982b).   Equation (6-5)  is
suggested for estimating annual  dermal  exposure to  chemical  substances in
residues or to dyes and other chemicals on clothing in  cases  where  the
amount of chemical  substance deposited  on the fabric surface  is  known or
can be estimated.   This equation 1s adapted from an equation  used  by
Procter and Gamble  to determine  dermal  absorption of sodium LAS present
in detergent residues on clothing.
                                    110

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                       DEX  = ADF  x TF x AV  x  FQ  x WF
                                                       (6-5)
where
     DEX  =
     ADF  =

     TF  =

     AV  =
     FQ  -
     WF  =
annual dermal exposure (mg/year)
amount of product or residue deposited on the fabric surface
(mg/cm2)
fraction of residue transferred to the skin per exposure event
(event-1)
area of skin surface exposed (cm2)
frequency of events per year (events/year)
weight fraction of chemical substance of Interest 1n product or
residue.  (This value 1s equal  to 1  where the product or residue
1s the chemical of Interest.)
Note that for substances formulated to adhere to fabric, such as dyes, an
arbitrary transfer factor of ten percent for a given exposure event would
probably yield a vast overestimate of dermal exposure under most
conditions.  It 1s suggested that the assessor arbitrarily assume the
percent of dye that would be lost during a lifetime of wearlngs.  The
assessor can then assume that a major portion of the dye would be lost
when the fabric 1s washed.  The remaining fraction of dye could then be
assumed to be lost during fabric wear.  Information regarding the typical
lifetime of the cloth Item and on the number of times that an Individual
would contact or wear the Item could be used to estimate the fraction of
dye transferred to the skin per event.  Some of this information can be
found 1n The Generic PMN Report on Surfactants (JRB 1982b) prepared for
the Exposure Evaluation Division of the Office of Pesticides and Toxic
Substances of the U.S. Environmental Protection Agency.  Trade
associations representing the textile industry may also be a source for
this information.

6.2.4  Ingestion Exposure

    Methods for assessing exposure resulting from Ingestion are
delineated in this section for two pathways:  Exposure due to Ingestion
of chemical substances leached out of objects used in the mouth and
exposure resulting from unintentionally swallowing liquids used in the
mouth.   A method for estimating Ingestion exposure as a result of
swallowing inhaled particles too large to be respired 1s described in
Appendix A.

    (1)   Ingestion Exposure to Chemical Substances Leached Out of Objects
Designed to Be Used in the Mouth.   Athletic  mouth guards, pacifiers,  and
teethers can serve as sources of chemical  substances that can be
ingested.   For example,  children place teethers  and/or pacifiers in their
mouths  and suck or chew on them.  In the process, chemical  substances may
                                    111

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 leach or diffuse from the object Into saliva and may subsequently be
 swallowed.  Exposure from this pathway can be estimated 1f experimental
 data on the rate of leaching of the chemical substance from the object
 Into saliva are available.  The basic equation for estimating annual
 1ngest1on exposure to a chemical substance that has leached out of an
 object used 1n the mouth 1s as follows:
                          ING = LR x SAO x D x F                 (6-6)
where
    ING = annual Ingestion exposure (mass/year)
     LR = experimentally determined leaching rate of the chemical
          substance from the object Into saliva (mass/hr/cm2)
    SAO = surface area of the object being placed In mouth (cm?)
      D = duration of exposure (hours/event)
      F = annual frequency of exposure events (events/year).

A major limitation of this method 1s the necessity of using experimental
data on rate of leaching of the specific chemical substance from the
object.

    (2)  Ingestion Exposure from Unintentionally Swallowing Liquids Used
1n the Mouth.  Toothpaste and mouthwash are examples of consumer products
Intended to be used 1n the mouth but not Intended to be consumed.  The
basic equation for estimating annual Ingestion exposure to chemical
substances present 1n liquids used 1n the mouth that are swallowed
unintentionally 1s as follows:
                          ING = WF x M x LUS x F
                                                       (6-7)
where
    ING
     WF
      M
    LUS
      F =
annual Ingestion exposure (mass/year)
weight fraction of chemical substance In liquid (unltless)
mass of liquid used per exposure (mass/event)
fraction of liquid used In the mouth that Is swallowed
unintentionally (unltless)
annual frequency of exposure events (events/year).
A major limitation of this method 1s that there are no data to support
any generalization regarding the proportion of liquids used In the mouth
that may be swallowed unintentionally.  Consequently,  an arbitrary value
must be selected for this parameter.
                                    112

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 6.3    Absorbed  Dose

 6.3.1  Inhalation

    Absorption from the lung of toxicants that are gases, volatilized
 liquids, or  liquid aerosols 1s usually rapid and complete, since the lung
 surface 1s large (50 to 100 square meters) and blood flow to the lung 1s
 high and 1n  proximity to the alveolar air (10 pm) (Casarett and Doull
 1975).  Absorption of liquids 1n aerosols probably occurs by diffusion;
 therefore, I1p1d-soluble compounds are absorbed most readily.

    Partlculate matter reaching the alveoli can be removed by three major
 routes:  (1) direct translocatlon of the toxicant from the alveoli Into
 the blood, (2) removal via the bronchi to the gastrointestinal tract, and
 (3) migration via the lymphatic system (Casarett and Doull 1975).
 Removal of partlculate matter via direct translocatlon of the toxicant
 from the alveoli Into the blood is an Important route for soluble
 compounds.   Removal via the bronchi to the intestinal tract appears to be
 composed of  a relatively rapid clearance phase (1 day) that 1s not
 affected by  the nature of the toxicant and a much slower phase (days to
 years) that  1s dependent on the nature of the toxicant.  Particles can
 penetrate the interstitial tissue of the lung and migrate via the
 lymphatic system as free particles or engulfed in cells that consume
 debris and foreign bodies (phagocytes).   Partlculate material can remain
 1n the lymphatic tissue for long periods of time.  Some particulates may
 remain in the alveolus indefinitely, however, in cases where lung tissue
 proliferates to form a plaque or nodule around the particle.

 6.3.2    Dermal

    In order to be absorbed through the skin, a substance must pass
 through epidermal cells,  the cells of the sweat or sebaceous  glands,  or
 hair follicles.  Most substances pass through epidermal cells.   Chemicals
must pass through a large number of cells:   the outer densely packed
 layer of horny, keratinlzed epidermal cells;  the germinal layer  of the
 epidermis; the corium; and the systemic  circulation.   For lung or
 gastrointestinal absorption, on the other hand,  a substance need pass
 through only two cells.

    The first phase 'of percutaneous absorption is diffusion through the
 epidermis, which is rate-limiting.   The  stratum corneum is much  thicker
 in some areas than others.  The stratum corneum conjunctivum area is  the
 least permeable.  Polar and nonpolar substances  diffuse by different
molecular mechanisms.   Polar substances  diffuse  through the outer surface
 of the protein filaments  of the hydrated  stratum corneum, while  nonpolar
molecules probably dissolve in and diffuse  through the nonaqueous  lipid
matrix between the protein filaments.  The  rate  of diffusion  of  nonpolar
                                   113

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substances is related to the 11p1d solubility and inversely related to
the molecular weight.  The second phase 1s clearance of substance from
dermls, which is much less compact than epidermis, and passage into
circulation.  The latter phase depends on blood flow, interstitial fluid
movement, lymphatics, and other factors (Casarett and Doull 1975).

    Brown et al. (1984) present a comprehensive list of variables that
influence rate and amount of skin absorption.  Variables such as amount
of skin surface area exposed, duration of exposure,  and type of skin
exposed are acknowledged by Brown et al. (1984) to influence absorption.
Other variables reported by Brown et al. (1984) to influence absorption
are discussed below.
    •  Hydration -
Absorption is reported to increase with increasing
hydration of the skin.  If the skin 1s hydrated
(covered with perspiration, Immersed 1n water) or
the chemical substance being absorbed is in
solution, diffusion and penetration will be
enhanced.  A pure liquid solvent, on the other hand,
will dehydrate skin and elicit compaction of the
stratum corneum, which will act to slow absorption
of the chemical.
    •  Temperature - Increased skin or solute (water)  temperature is
                     reported to enhance skin absorption capacity
                     proportionately.
    •  Skin
       Condition
    •  Regional
       Variability
    •  Individual
       Variability
Any damage (sunburn, cuts, wounds, abrasions) to the
stratum corneum is reported to compromise its
ability to act as a barrier against foreign
substances.

The epidermis of the hand is reported to represent a
greater barrier to penetration than the epidermis of
many other parts of the body; penetration through
the scrotum is estimated to be 100 percent.

Absorption rates are reported to vary among
individuals, and even for the same individual over
time.  Variables such as age, sex, ratio of body fat
to total weight, previous exposure, nutrition, type
and amount of skin exposed, and the specific
conditions of exposure are all reported to affect
actual absorption.
                                   114

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     •   Physical and   Factors affecting absorption are  reported to  Include
        Chemical       11poph1"l1c1ty, polarity, volatility, molecular
        Properties     weight, carbon number, and solubility of the
        of the         chemical substance 1n the stratum corneum.  The pH
        Chemical       of a solution 1s also reported to affect absorption
        Substance -    of the solution.

     •   Vehicles and   Various compounds such as alcohols, solvents, and
        Accelerants -  chloroform are reported to demonstrate permeability-
                      enhancing effects.  Soaps and surfactants are also
                      reported to Increase skin permeability significantly.

     •   Synerg1st1c    Combinations of compounds are reported to have
        Effects -      greater effects on the stratum corneum and to be
                      absorbed more readily.

     Brown et al. (1984) also reported findings from a  review of the
existing literature on absorption rates of volatile solvents 1n aqueous
solutions having direct contact with skin.  According  to this review, for
dilute  aqueous solutions, absorption of solute is directly proportional
to concentration 1n accordance with Pick's law; for pure or highly
concentrated liquids, however, this relationship is not necessarily
true.   In fact, much  experimental evidence exists indicating that
permeation rates are  actually Increased with dilute aqueous solutions as
compared to pure liquids.  Investigators reportedly attribute this effect
to the  compaction and dehydration of the stratum corneum when in contact
with pure liquids,  1n addition to other factors.   The  implication of the
findings from this  literature review is that the use of absorption rates
obtained from experiments with pure chemicals may considerably
underestimate absorption of chemical  substances 1n dilute aqueous
solutions.

    The following subsections present equations and describe methods that
can be  used to estimate dermal absorption of chemical   substances  via
three exposure pathways : (1) dermal  absorption from exposure to  a film
of liquid deposited on the skin;  (2)  dermal  absorption from exposure
during  immersion of skin in liquids;  and (3)  dermal  absorption during
exposure of skin to chemical  substances contained  in or adhering  to solid
matrices.  The equation for estimating dermal  absorbed dose is the same
for exposure to a film of liquid  on the skin and  for exposure during
immersion of skin 1n  liquids.   For purposes  of  estimating dermal  absorbed
dose, these two exposure pathways are grouped  together.  The method used
is referred to as the method  for  estimating  absorbed  dose resulting from
dermal contact with liquids.   This  method  is  presented in section (1).
The method  for estimating dermal  absorption  during exposure of skin to
chemical substances contained 1n  or adhering to solid  matrices is
presented in section  (2).   A  method for estimating absorbed dose  for
                                    115

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solids not 1n solution  (I.e., dusts and powders) 1s not delineated.  No
information was found in a  limited Information search to predict dermal
absorbed dose for solids not in solution.

    (1)  Method for Estimating Dose Absorbed as a Result of Dermal
Contact with Liquids.   The  parameters required to estimate dermal
absorption are the same for contact with liquids via any exposure
pathway.  The following equation can be used to estimate dermal
absorption resulting from contact with liquids.

                        ADD = C x D x AV x Kp x FQ               (6-8)

where

    ADD = annual dermal dose (mg/year)
      C = concentration of  chemical substance in the liquid medium (mg/1)
      D = duration of dermal exposure (hours/event)
     Kp = permeability  constant (liters/cm? x hours)
     FQ = frequency of  exposure events per year (events/year).

The permeability constant (Kp) is influenced by such factors as the
absorption rate and concentration of the chemical substance.  The
absorption rate 1s, 1n  turn, determined by factors such as skin
condition, chemical and physical properties of the chemical substance,
and other factors discussed previously in Section 6.3.2.  Where skin
absorption rate and concentration are known, for dilute aqueous
solutions, the permeability constant can be calculated using Fick's law.
The following equation  expresses Fick's law.

                              Js = Kp A Cs                       (6-9)

where

    Js = permeation rate (flux)  of the solute (mg/cm2 - hr)

    Kp = permeability constant (liters/cm2 - hr)

   ACS = concentration difference of the solute across specified
         tissue (mg/liter).

Additional experimental  data are needed, however, to determine the
relationship between skin absorption rate and concentration for highly
concentrated or pure chemicals.   Furthermore, more experimental data are
needed to determine at what concentration of a chemical substance the
assumption of linearity (proportionality) no longer holds  true.
                                    116

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     (2)  Method for Estimating Dermal Absorption During Exposure of Skin
to Chemical Substances Contained 1n or Adhering to Solid Matrices.  The
following equation has been used by Procter and Gamble (JRB 1982b) to
estimate dermal absorption of sodium LAS present In residues on clothing
surfaces.
                    ADD = ADF x TF x AV x FA x FQ x WF
(6-10)
where
    ADF = amount of product or residue deposited on the fabric surface
          (mg/cm2)
     TF = fraction of residue transferred to the skin per exposure event
          (unltless)
     AV = area of skin surface exposed (cm2)
     FA = fraction of chemical substance absorbed (unltless)
     FQ = frequency of exposure events (events/year)
     WF = weight fraction of chemical substance of interest 1n product or
          residue;  (This value is equal to 1 where the product or
          residue is the chemical of interest.)
Because of a general lack of data on the tendency for substances to
transfer to skin, an arbitrary factor must be used.  In the assessment of
consumer exposure to sodium LAS in detergent residues on clothing,
Procter and Gamble used an arbitrary value of .10 to represent the
fraction of detergent residue transferred to the skin per exposure event
(JRB 1982b).  No information has been found regarding arbitrary values
used 1n consumer exposure assessments to represent the fraction of dyes
transferred to skin per exposure event.  The qualitative method based on
estimates of the percent of dye that would be lost during a lifetime of
wearings, described 1n Section 6.2.3(3), can be used in the absence of
quantitative data for this parameter.  Another limitation of this method
is that the fraction of chemical substance absorbed over the period of
exposure must be known.  This requires experimental data on dermal
absorption of chemical substances for which absorption is being
estimated.  If such data are lacking for the specific chemical substance
for which absorption is being estimated, absorption data for analogues of
the chemical substance must be used, if available.  Even if experimental
data on absorption are available, such data must be used with the
understanding that absorption measured during the experimental condition
may not necessarily be applicable to factors contributing to absorption
during the exposure event.
                                    117

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6.3.3     Ingestlon

    Absorption from the gastrointestinal tract can occur anywhere along
Its length, from the mouth to the rectum.  For example, some drugs are
administered subllngually (e.g., nitroglycerine) where they are absorbed
rapidly;  also, when substances are absorbed via oral mucosa, passage
through the liver 1s minimized, retarding metabolism of the substance
(Goodman  and Oilman 1975).

    If a  substance is a weak organic acid or base, it will tend to be
absorbed  by diffusion in the part of the gastrointestinal tract in which
1t exists in the most Hpid-soluble form.  Since the gastric juice is
very add and the intestinal contents are nearly neutral, the Hpid
solubility of a substance can be very different in these two areas.  For
example,  a weak organic acid (e.g., benzole acid) is 1n the nonionized
lipid-soluble form in the stomach and therefore tends to be absorbed by
the stomach.  However, a weak organic base (e.g., aniline) 1s not in the
lipid-soluble form in the stomach but 1s lipid soluble 1n the intestine,
so it tends to be absorbed 1n the intestine.  Because of their large
surface area, however, the intestines will continue to absorb nonionized
chemicals present as long as the equilibrium maintains a finite
concentration of them available for absorption (Casarett and Doull 1975).

    Specialized transport systems occur in the gastrointestinal tract for
the absorption of nutrients and electrolytes.   For example, there are a
number of carrier systems for the absorption of certain sugars, amino
adds, and pyrimidlnes, as well as for Iron, calcium, and sodium.
Pollutants can often be absorbed by these systems, e.g., 5-fluorasil  by
the pyrimidine transport system, thallium by the system that normally
absorbs iron, and lead by the system that normally transports calcium.
Some metals are absorbed by a two-step process.  For example, iron first
diffuses  into Intestinal cells and then is actively transported into the
blood; cobalt and manganese compete for this transport system (Casarett
and Doull 1975).

    Particles can be absorbed by the gastrointestinal epithelium,
including azo dyes of nearly 100 ym diameter,  and polystyrene latex
particles from an emulsion,  up to 220 jjm in diameter.

    The following are some of the factors that influence gastrointestinal
absorption (Casarett and Doull 1975):

    •  Stability of substance to the acids,  enzymes,  and flora of  the
       gastrointestinal system.

    •  Presence of compounds that increase absorption;  e.g.,  EDTA  alters
       the state of membranes by removing calcium, thus increasing
       permeability to bases, acids,  and neutral  compounds alike.
                                    118

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    •  Alteration of gastrointestinal motnity.

    •  Dissolution rate 1f substance 1s Insoluble.

    •  Size of particles.

    •  Bulk content of food mass.

Also, complexes with other substances 1n food may decrease absorption
(Goodman and GUman 1975).

    The complexity of the above factors makes 1t difficult to predict
absorption.  For example, the fully Ionized quaternary ammonium compound,
pralldoxime (2-PAM), 1s not expected to be absorbed on the basis of the
pH-part1t1on hypothesis described earlier.  Nevertheless,  experimental
results show that 1t 1s almost completely absorbed from the gastro-
intestinal tract (Casarett and Doull 1975).  Because the factors that
determine gastrointestinal absorption are highly situation-specific and
lack common quantifiable parameters, no methods for estimating
gastrointestinal  absorption are delineated herein.
                                   119

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120

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 7.        REFERENCES
 Anderson  E,  Browne N,  Duletsky S, et al.  1984.   Development of
 statistical  distribution or  ranges of  standard  factors used In exposure
 assessments.   Revised  draft  final report.  Washington, DC:  Office of
 Health and Environmental Assessment, U.S. Environmental Protection
 Agency.   Contract No.  68-02-3510.

 ASHRAE.   1977.  American Society of Heating, Refrigerating and
 Air-conditioning Engineers.  ASHRAE handbook and  product directory 1977
 fundamentals.  New York:  American Society of Heating, Refrigerating and
 A1r-Cond1t1on1ng Engineers,  Inc.

 Battelle.  1979.  Formulation data for hydrocarbon-propelled aerosol
 products  under CPSC jurisdiction.  Washington,  DC:  U.S. Consumer Product
 Safety Commission.  Contract No. CPSC-C-78-0091.

 Becker D, Fochtman E,  Gray A, Jacobius T.  1979.  Methodology for
 estimating direct exposure to new chemical substances.  Washington, DC:
 U.S. Environmental Protection Agency.  EPA-560/13-79-008.

 Bird TD, Wallace DM, Labbe RF.  1982.  The porphyria, plumblsm, pottery
 puzzle.  JAMA 247:813-841.

 Booser ER.  1981.  Lubrication and lubricants.  In:  Kirk-Othmer
 Encyclopedia of Chemical Technology.   3rd ed.  New York:   John Wiley &
 Sons.

 Brown HS, Bishop DR, Rowan  CA.  1984.  The role of skin absorption as a
 route of exposure for  volatile organic compounds  (VOCs) in drinking
water.  AJPH 74:479-484.

 Carlson JE, VUlaveces JW.   1977.  Hypersensitivity pneumonitls due to
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                                    122

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                                    125

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126

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                                     X        "    *

                       APPENDIX A

Method for Estimating Inhalation Exposure to Participates
            Discharged from Consumer Products
                           127

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     (1)   Introduction.  Airborne participates in the volume of inhaled
air  have  several possible  fates.   Particles orglnally in the volume of
inhaled air may not  even enter the respiratory system.  The aspiration
efficiency (the fraction of particles originally in the volume of Inhaled
air  that  enters the  nose or mouth) depends on particle size, air
velocity, inhalation  flow  rate, and whether nose or mouth breathing is
used.  When averaged  over  all wind directions for winds ranging from 0.75
m/sec to  2.75 m/sec  (typical conditions), the maximum aspiration
efficiencies for particle  sizes of 1 urn, 5 urn, and 10 urn are 100 percent,
85 percent, and 70 percent, respectively.  Aspiration efficiency drops
slowly for particle  sizes  larger than 10 urn; aspiration efficiencies for
particles 30 urn and  60 urn  in diameter are 50 percent and 35 percent,
respectively (Hinds  1982).

     Once  inhaled, particles may undergo respiratory tract deposition or
they may  be exhaled without deposition.  Total deposition, as the term is
used here, is defined as the average probability of an inspired particle
touching  a surface of the  respiratory tract and thereby being deposited
(Heyder et al. 1980b).  The respiratory tract may be divided into three
deposition regions, based  on the physical processes governing deposition
and  the ultimate fate of deposited particles.  Deposition in the head
region (i.e., nose, mouth, pharynx, and larynx) is the result of
sedimentation and impaction (Hinds 1982).  This region effectively
filters out all inhaled particles greater than 10 urn 1n diameter, and a
large number of particles  in the 1 urn to 10 urn range.   The
tracheobronchial region, which comprises the airways from pharynx to
terminal  bronchioles, traps many smaller particles in  the 0.01  urn to 10
urn size range by impaction and sedimentation (Meyer 1983,  Hinds 1982).
Particles 0.01 urn to 10 urn in diameter that pass through the bronchioles
are available for deposition via diffusion and sedimentation in the
alveolar  region of the lungs.  Particles deposited in  the head  and
tracheobronchial regions are either cleared to pharynx and swallowed,
thus available for indirect ingestion exposure via the gastrointestinal
tract, or are expelled with sputum.  Thus,  of the mass of  inhaled
partlculates, only the respirable particles (i.e.,  particles small enough
to reach  the alveolar region) are available for exposure via the lungs.

    Most  exposure assessments have neglected to distinguish between
Inhaled chemicals destined for the lungs and inhaled chemicals  destined
for the gastrointestinal tract.   Equation (A-l)  below  represents the
traditional  approach to assessment of inhalation exposure.

                           EI = I > C(t)dt                 (A-l)

where

       Ej = inhalation exposure (mass/time)
        I = inhalation rate (volume/time)
        t = duration of exposure (time)
       Cj. = concentration of chemical in air as  a function of time
            (mass/volume).
                                   128

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    While the traditional approach 1s suitable for chemicals in gaseous
or vapor form and as a model for "worst case" exposure to chemicals in
particulate form, a more refined approach, which distinguishes between
pulmonary and gastrointestinal exposure to partlculates, will enhance the
precision of both exposure and risk assessments.  Therefore, the methods
presented in this Appendix will depart from the traditional approach by
providing algorithms that allow for separate estimates of the pulmonary
and gastrointestinal tract components of Inhalation exposure for inhaled
partlculates, to be used at the discretion of the exposure assessor.  It
should be stressed that, despite the distinction made here between
pulmonary exposure and gastrointestinal exposure, these methods do not
include calculation of absorbed dose.  The factors that govern the extent
to which Inhaled substances are absorbed are largely chemical-specific;
therefore, the prediction of absorbed dose is not currently amenable to
the generic approach that 1s the foundation of this report.

         (2)  Exposure Calculation.  Assessment of Inhalation exposure to
consumer products involves finding a simple or complex solution to
equation (A-l) and Identifying appropriate parameter values.  In
practice, the algorithm used to calculate inhalation exposure 1s usually
an Integrated and simplified version of equation (A-l), often
incorporating simplifying assumptions about the change in concentration
with time.  (See Section 4 for a detailed discussion of methods for
calculating concentration.)  In many cases, exposures can be calculated
using an average concentration for a given period of time; exposures from
several such consecutive time periods can be summed to estimate total
inhalation exposure to a given product.  The simplified version of
equation (A-l) is presented below.

                          IHX = IR x DU x FQ x CN                (A-2)

where

       IHX = quantity inhaled (mg/yr)
        IR = inhalation rate (m3/hr)
        DU = duration of exposure event (hours)
        FQ = frequency of exposure (events per year)
        CN = Indoor air concentration of a given constituent (mg/m3).

    If precise estimates of exposure are desired,  modifications  of the
above equation can be made for chemicals present in air as particulates,
to account for the previously mentioned variation  1n  both total  and
regional deposition as a function of  particle size.   In this case,  the
total exposure to inhaled particulates  is calculated  using equation
(A-3), which includes a term (TDF)  that accounts for  the  fraction  of
Inhaled particulates deposited in the respiratory  tract.   (Note  that
aspiration efficiency is assumed  to be  100 percent,  a worst case
assumption.)
                                    129

-------
                      IHX  =  IR x DU x  FQ x CN  x TDF               (A-3)
where
        IHX,  IR, DU, and FQ are as used 1n equation (A-2).

        TDF = total deposition fraction, which is the weight fraction of
             inhaled particles deposited in the respiratory tract.

    The total exposure to particulates calculated in equation (A-3) can
be divided into the pulmonary region exposure (IHXp) and the gastro-
intestinal tract exposure (IHXg), using equations (A-4) and (A-5),
respectively.  This partitioning of inhalation exposure is an option that
may be worthwhile for chemicals whose effects depend on the mode of entry
into the body.
                    IHXp = IR x DU x FQ x CN x RF

                    IHXG = IR X DU X FQ X CN X NRF
                                                    (A-4)

                                                    (A-5)
where
        RF =
respirable fraction,  which is the weight fraction of all
inhaled particles deposited in the pulmonary airspaces
       NRF = nonrespirable fraction, which is the weight fraction of all
             inhaled particles deposited in the head or tracheobronchial
             regions.

    For the purpose of this analysis, it is assumed that all of the
inhaled particulates that are deposited in the respiratory tract are
destined for either the lungs or the gastrointestinal tract, as shown in
equation (A-6).  (No information was available on the fraction of
material initially deposited in the head or tracheobronchial region that
might be subsequently expelled with sputum.)
                        IHX = IHXp + IHX(j
                                                    (A-6)
         (3)  Inhalation Exposure Parameters.  Information on the
parameters included in equations (A-2) through (A-6) above is presented
in this subsection.  Parameters are listed in alphabetical order.

         (a)  CN.  Chemical concentration in the air, expressed in
mg/m3, can be calculated in a number of ways, as discussed in
Section 4.  Depending on the particular exposure scenario, the
concentration may be taken as constant or as changing over the period of
exposure.  Among the variables that affect concentration are total
quantity of chemical released, release rate of the chemical, room size,
ventilation rates, and time lapse.

                                  .  130

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          (b)   DU.   Duration  of  exposure  is discussed  1n general 1n
Section  6.2.   An  Inhalation  exposure event can be measured  in seconds,
minutes,  or hours.   Inhalation  exposure  to many consumer products can be
divided  Into  several  stages,  each of which may have a different
duration.  For example,  exposure to an aerosol product during active use
may  last  for  only seconds or  minutes.  Passive exposure to  direct release
of that  product may  last for  hours.  And, 1f the aerosol product Is a
coating  (e.g., spray  paint)  applied to an object that remains Indoors, a
third  Inhalation  exposure stage, consisting of the period during which
the  chemical  release  rate 1s  controlled  by diffusion  from the solid
coating,  may  last for weeks  or  months.

     There are  several ways to obtain estimates of duration  for Inhalation
exposure  scenarios.  Methods  used for estimating the duration for an
Inhalation exposure  scenario  are determined by whether the  assessor is
concerned primarily with exposure during active use of the  product or
with exposure  during passive  use, or both.  A method for estimating
duration  of active exposure during the application of coatings to
surfaces  is presented in detail 1n Section 3.1 of this volume.  In some
cases, estimates of duration  can be made based on literature values or
professional judgment.  Additional general guidelines to follow for
estimating duration are presented in Section 6.2.1  of this  volume.

          (c)   FQ.  Frequency of exposure, expressed 1n exposure events
per year, is discussed in Section 6.2.1.

          (d)   IHX.  Total individual inhalation exposure,  expressed in
mg/year,  refers specifically to the quantity of inhaled particulates that
are likely to  be deposited in the respiratory tract.   Depending on the
particle  size  distribution of the inhaled aerosol,  this quantity may be
equal to or significantly less  than the quantity inhaled.    In practice,
there may not  be sufficient data on particle size distribution to
estimate the quantity deposited in the respiratory  tract;  in such  cases,
100 percent deposition can be assumed as  a worst case.

         (e)    IHXp.   Pulmonary  Inhalation exposure,  measured in terms
of mg/year, 1s the quantity of  inhaled particulate  material  that is
available for alveolar absorption.   (This is  to be  distinguished from the
quantity that  is absorbed across the alveolar membrane,  which is not
addressed in this report.)   IHXp depends  on  the respirable fraction  RF
(see (1) below),  which in turn depends on the particle size  distribution
of the Inhaled aerosol.

         (f)    IHXg.   Gastrointestinal  inhalation exposure, measured  as
mg/year, is the quantity of inhaled particulate material  that is
initially deposited  in the head or  tracheobronchial  region,  thus subject
to gastrointestinal  rather than pulmonary exposure.   As  with IHXp,
IHXQ depends  on the  particle size distribution of  the  inhaled aerosol
                                    131

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via a deposition factor, NRF (see below).  The portion of IHXg that 1s
expelled from the body via nose-blowing or expectoration, and thus not
available for exposure, is assumed to be insignificant for the purpose of
these exposure calculations.

         (g)  IR.  Inhalation rate, expressed 1n m3/hr, is discussed in
Section 6.2.2.

         (h)  NRF.  The nonrespirable fraction is a unitless parameter,
ranging from 0 to 1, that represents the weight fraction of inhaled
particulates initially deposited in the head and tracheobronchlal regions
of the respiratory tract, and thus not available for exposure via the
lung.  Particles deposited in these areas are cleared to the
gastrointestinal tract.  Values for NRF of particulates discharged from
select consumer products are presented in Table 29 at the end of Appendix
A.  NRF 1s calculated by using equation (A-7), provided that the
supporting data on particle size distribution are available,*  If there
are Insufficient data for equation (A-7) but the mass median diameter is
known, a less reliable estimate of NRF can be made using the ICRP model
1n Figure 3 (see discussion of TDE below).

               n
         NRF = I   [(TDE1 - PDEi) x WF^j ]                  (A-7)
               1=1

        TDEj = total  respiratory tract deposition rate for particles
               within aerodynamic diameter size class 1 (a unitless
               fraction varying from 0 to 1)

        PDE^ = pulmonary deposition rate for particles within
               aerodynamic particle diameter size class i  (a unitless
               fraction)

         WF} = the weight fraction of particles in aerodynamic  diameter
               size class 1  (a unitless fraction).

    Detailed information on the applications  and  data sources for each  of
the parameters in equation (A-7) is provided  below:

    •  TDE.   The fraction of inhaled particles in a  given  size  range  that
       1s deposited in the respiratory tract  has  been studied both
       theoretically  and experimentally.   Theoretical  models  such as  the
       International  Commission on Radiological  Protection's  (ICRP)  Task
*Note:  Equation (A-7)  could just as easily be written as:
               NRF = TDF - RF
        See (j) for a discussion of TDF and (1) for a discussion of  RF.
                                   132

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Group on  Lung  Dynamics Model, presented as Figure 3, have been
used 1n the past  to determine deposition.  There are discrep-
ancies, however,  between the ICRP model, which relates deposition
to particle mass  median diameter (I.e., the diameter below which
lies 50 percent of the mass of the particles), and more recent
experimental data relating deposition to aerodynamic diameter.
For this  reason,  exposure estimates should be based on the
experimental data rather than the ICRP model 1n cases where
sufficient data on particle size distribution are available.
Total deposition  in the respiratory tract is the sum total of
deposition in  the head, tracheobronchial, and pulmonary regions.
Total deposition  depends on particle diameter, particle density,
total volume,  breathing rate, and type of breathing used (nose or
mouth) (Heyder et al. 1980b).  As discussed in Section (1),
particles ranging from 1 urn to 100 urn are retained in the head
region, and particles in the 0.01 urn to 10 urn range are absorbed
in the tracheobronchial tract or proceed Into the pulmonary cavity.

The relationship  between total respiratory tract deposition and
aerodynamic particle size 1s given in Figure 4, based on
information or data reported in Heyder et al. (1974), Heyder et
al. (1980a), Heyder et al. (1980b), Hinds (1982), Stahlhofen et
al. (1980), and Meyer (1983).  It should be noted that some of the
information reported in these sources 1s conflicting; Figure 5
represents a synthesis of the Information in all  of these
sources.   Two graphs are given in Figure 4,  one representing
deposition under  "typical" breathing conditions (i.e.,  normal  nose
breathing during rest or light activity),  the other representing
"maximum" deposition (i.e.,  maximum values reported in the
reviewed  literature).  Information on deposition  for particles
smaller than 0.1 urn is sparse and conflicting.   Deposition of
these small particles occurs largely by diffusion;  thus,  it cannot
be clearly expressed as a function of aerodynamic particle
diameter  (Heyder et al. 1980a).   A comparison of  Figure 4 with
Figure 5  Indicates that tracheobronchial  deposition accounts for
the majority of the total  deposition of smaller particles  in this
size range; this enhancement of  tracheobronchial  deposition can be
attributed to the rapid Brownlan motion (Hinds  1982).   A large
fraction  of particles smaller than 0.05 urn may  be exhaled  unless
they dissolve or react with  or on the surface (Meyer 1983).   Total
deposition of particles in the 0.1  urn to 1  urn size  range,  where
sedimentation becomes important  in addition  to  diffusion,  is lower
than for  smaller particles.   Deposition via  impaction in  the head
region becomes  increasingly  important for  particles  in  the 1  urn to
10 urn size range;  total deposition approaches  100 percent  for
particles larger than about  3 urn.
                             133

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             0.8
           c
           5
             0.4
           o
           o
             02
                             Nasopharynx
               -2-1         012





                   Particle mass median parameter  (ym)








  Figure 3.  ICRP Model  of Regional Respiratory Tract  Deposition



              as  a Function of  Particle  Size.
Source:  Meyer 1983.
                                 134

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CO
en
        1.0-
         .9 -
         .8 -
         .7 -
         .6 -
O
Q.
til

a
         .4 -
          3 -
         .2 -
          1 -
           01
                              II   I   I  I  11 r
                                      05         .1
                                                                  I   I
                                                     AERODYNAMIC PA«1ICLE OlAMElbR  (pm)
I     III

        5
                                                                                                                           10
                                                                                                 TYPICAL/NOSE BREATHING

                                                                                                 MAXIMUM VALUES
                                 FIGURE   4 .  TOTAL DEPOSITION OF PARTICULATE^ IN THE RESPIRATORY

                                              TRACT AS A FUNCTION OF PARTICLE flZE

-------
CO
en
          10 -
          0.9 -
                                                                                                          I    I    I   I  I  I   I
           01 -
             001
                                                       AERODYNAMIC PARTICLE DIAMETER  (pm)
                                                                                                         TYPICAL/NOSE BREATHING

                                                                                                         MAXIMUM VALUES
                                       FIGURE   5. PULMONARY DEPOSITION OF PARTICIPATES AS A
                                                    FUNCTION OF PARTICULATE SIZE

-------
 PDE.   The  fraction  of  Inhaled  particles  1n a given  size  range
 subject  to pulmonary deposition  has  been  studied both
 theoretically  and experimentally.  The discussion of discrepancies
 between  the ICRP model  (Figure 3) and experimental  data  1n
 relation to estimates  of  the parameter TOE applies  equally well to
 the parameter  POE.  A  summary  of the relationship between
 particle size  and pulmonary deposition 1s given 1n  Figure 5 based
 on data  or Information  reported  1n Heyder et al. (1974), Heyder et
 al. (1980a), Heyder et  al. (1980b),  Hinds (1982), Stahlhofen et
 al. (1980),  and Meyer  (1983).  The reader should be aware that
 other  factors  1n addition to particle size affect alveolar
 deposition;  these Include breathing  characteristics, such as type
 of breathing (nose  vs.  mouth), breathing  rate, and  tidal volume.
 Under  constant breathing  conditions, however, there 1s a clear
 relationship between aerodynamic particle diameter  and pulmonary
 deposition for particles  larger than about 0.1 urn.  The data
 summarized  1n  Figure 5  are discussed 1n more detail below.

 Figure 5 Includes two graphs, one representing deposition to be
 expected under typical  conditions (I.e., nose breathing during
 light  activity) and the other representing the highest deposition
 values reported 1n  the  reviewed literature.   No distinction
 between  "typical" and  "maximum" 1s provided for particles less
 than about  0.3 urn,  because the Information on deposition 1n this
 size range  1s  sparse.  The PDE values corresponding to aerodynamic
 particle diameters  less than 0.1  urn 1n Figure 5 were taken from
 Heyder et  al.  (1980a) who did not specify the origin of the data.
 The trend  1n decreasing pulmonary deposition with decreasing
 particle size  1n the 0.05 urn to 0.01  urn range 1s presumably
 related to  enhanced tracheobronchlal  deposition for this size
 range  (see  TOE, above).  Pulmonary deposition between 0.1 urn and 1
 urn 1s about 20 percent, Independent of particle size (Hinds
 1982).  Pulmonary deposition peaks again around 2.5 urn to 3 urn and
 approaches  0 around 6 to 7 urn.   Particles larger than 1 urn are
 Increasingly filtered out by the head region.  This  explains the
 decrease 1n pulmonary deposition with Increasing particle size for
 particles  larger than about 3 urn.  Figure 5  suggests that 0.75
might be used as a worst case estimate of PDE 1n cases  where
detailed particle size distribution data are not available.

WF.  The weight fraction of aerosol  particles in a  given
aerodynamic diameter size range 1,  must  be known or  estimated  1n
order to estimate regional deposition in the respiratory tract.
 Because of the limited availability of particle size distribution
 Information, WF will often be the stumbling  block  in exposure
calculations Involving inhaled  partlculates.   Particle  size
distribution information 1s available for a  number  of  aerosol  can
products and can be found in various  trade association  journals.
                             137

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       Typical particle size distributions for other types of
       participates (e.g., asbestos fibers, household dust, cigarette
       smoke) generated during the use of consumer products have, In some
       cases, been measured 1n health-related studies.  A complete
       particle size distribution may not be necessary for crude worst
       reasonable case exposure calculations.  Considerable professional
       judgment will be needed by the exposure assessor 1n converting
       available Information on particle size distribution to WF in
       equation (A-7).  In cases where the only Information available 1s
       the mass median diameter, this parameter can be used 1n
       conjunction with data 1n Figure 3 to estimate respiratory tract
       deposition.

       (1) RF.  The resplrable fraction 1s the fraction of Inhaled
aerosol particles likely to be deposited In the pulmonary airspaces.
This parameter, which ranges from 0 to about 0.7, 1s a function of the
particle size distribution of the Inhaled aerosol and can be calculated
using equation (A-8), providing that sufficient data are available.  A
less accurate estimate of RF can be made using the model given 1n Figure
3 1n conjunction with the mass median diameter (see discussion under TOE
1n (h), above).

                            n
                       RF = I   (PDE1 X WFi)                        (A-8)
                            1=1

       A detailed explanation of the parameters used 1n equation (A-8)
can be found under NRF (see (1)).   It should be obvious that the data
provided 1n Figure 5 are essential In calculating RF.  Values of RF of
partlculates discharged from selected consumer products are presented In
the Table at the end of Appendix A.

       (j) TDF.  The total deposition fraction 1s the weight fraction of
all Inhaled particles deposited 1n the respiratory tract.   This parameter
can be calculated using equation (A-9), providing that the particle size
distribution 1s known.  A cruder estimate of TDF can be made using the
model given In Figure 3 In conjunction with the mass median diameter (see
discussion under TDE 1n (h), above).

                              n
                        TDF = I (TDEi X WFi)                        (A-9)
                              1=1

    A detailed discussion of these parameters is included  in the
discussion of NRF (see (i), above).  It must be noted that data on TDF
particulates discharged from selected consumer products are not presented
in the table at the end of Appendix A.  In all cases where nonrespirable
and respirable fractions of particulates were calculated or estimated,  a
                                    138

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maximum value for TDF of 1.0 was used.  The total deposition, or average
probability that an Inspired particle may undergo respiratory tract
deposition, was not considered 1n this analysis.  Precise data on
aspiration efficiency according to particle size are needed to accurately
quantify the TOP of partlculates.  Aspiration efficiency, or the fraction
of particles originally 1n the volume of Inhaled air that enters the nose
or mouth, 1s dependent on a number of factors.  These Include particle
size, air velocity, Inhalation flow rate, and whether nose or mouth
breathing 1s used.  To circumvent the difficulties Involved 1n attempting
to quantify each of these factors, as a worst case,  the aspiration
efficiency was assumed to be 100 percent.  As a result, a maximum value
for TDF of 1.0 1s suggested for use 1n all  calculations requiring this
parameter.  The value of 1.0 for TDF, however, represents a worst case
assumption.
                                   139

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                     Table 29.  Values of Respirable and Nonrespirable Fraction of Particulates for Selected Consumer Products (continued)
Aerosol product
    Nonrespirable fraction	
Minimum     Typical     Maximum
                                                                       Respirable fraction
                        Minimum     Typical      Maximum
Comments
Deodorant/antiperspirant      0.66
Hairspray
Furniture polish
  0.66
  0.5
General cleaner/
 disinfectant
 Insecticide, home
 and garden
 Insect  repel 1ant
  0.5
0.88        0.96          0.04        0.12        0.34      Calculated using typical  and maximum pulmonary
                                                            deposition factors presented in Figures 4 and 5 and
                                                            available data on particle size distribution of
                                                            particulates discharged from deodorants/
                                                            antiperspirants.3

0.88        0.97          0.03        0.12        0.34      Calculated using typical  and maximum pulmonary
                                                            deposition factors presented in Figures 4 and 5 and
                                                            available data on particle size distribution of
                                                            particulates discharged from hairspray.b

0.82        1.0         7.6x10"^      0.18        0.50      Calculated using typical  and maximum pulmonary
                                                            deposition factors presented in Figures 4 and 5 and
                                                            available data on particle size distribution of
                                                            particulates discharged from aerosol furniture
                                                            polish.0

0.87        0.97          0.03        0.13       —         Calculated using typical  and maximum pulmonary
                                                            deposition factors presented in Figures 4 and 5 and
                                                            available data on particle size distribution of
                                                            particulates discharged from aerosol disinfectant.01

0.92        0.98          0.02        0.08       —         Calculated using typical  and maximum pulmonary
                                                            deposition factors presented in Figures 4 and 5 and
                                                            available data on particle size distribution of
                                                            particulates discharged from products designed for use
                                                            on flying insects.6

            1.0           0          —           0.5       Values are estimates based on ranges of values
                                                            calculated for other aerosol products.
                                                                                           I"

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                          Table 29.   Values of Respirable and Nonrespirable Fraction of Particulates  for  Selected Consumer  Products
Aerosol product
Lubricant

Oven cleaner

Pet pesticide

Room deodorizer
Nonrespirable fraction

Minimum Typical Maximum
	 	

0.5

0.5

0.64
1.0

1.0

1.0

0.92
Respirable fraction
Minimum Typical Maximum
0.5 0.5 0.5

0.5

0 — 0.5

0.08 — 0.36
Garments
Values are estimates based on ranges of values
calculated for other aerosol products.
Values are estimates based on ranges of values
calculated for other aerosol products.
Values are estimates based on ranges of values
calculated for other aerosol products.
Calculated using typical and maximum pulmonary
Spray starch
Suede cleaner/polish
Fabric protector
Home spray paint
0.5
0.78
Automotive touch-up paint     0.78
            0.52
0.92
            0.92
                        1.0
            0.94
            0.83
                       6x10-
0.06
0.17
0.48
            0.08
                                      0.08
          deposition factors presented in Figures 4 and 5 and
          available data on particle size distribution of
          particulates discharged from aerosol  room
          deodorizer.f

          Calculated using typical and maximum pulmonary
          deposition factors presented in Figures 4 and 5 and
          available data on particle size distribution of
          particulates discharged from spray starch.9

0.5       Values are estimates based on ranges of values
          calculated for other aerosol products.

          Calculated using typical and maximum pulmonary
          deposition factors presented in Figures 4 and 5 and
          available data on particle size distribution of
          particulates discharged from aerosol fabric
          protector."

0.22      Calculated using typical and maximum pulmonary
          deposition factors presented in Figures A-2 and A-3
          and available data on particle size distribution of
          particulates discharged from spray paints.1

0.22      Values are assumed to be the same as those for home
          spray paint.

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APPENDIX  A  -  REFERENCES

Heyder  J, Armbruster  L, Gebhart J, Greln E, Stahlhofen W.  1974.  Total
deposition  of aerosol particles 1n the human  respiratory tract for nose
and mouth breathing.  J. Aerosol Science 6:311-328.

Heyder  J, Gebhart J,  Stahlhofen W.  1980a.  Inhalation of aerosols:
particle  deposition and retention.  In:  Wllleke K, ed.  Generation of
aerosols  and  facilities for exposure experiments.  Ann Arbor, MI:  Ann
Arbor Science, pp. 65-104.

Heyder  J. Gebhart J,  Rudolf G, Stahlhofen W.  1980b.  Physical factors
determining particle  deposition 1n the human  respiratory tract.  J.
Aerosol Science 11:505-515.

Hinds WD.   1982.  Aerosol technology—properties, behavior, and
measurement of airborne particles.  New York, NY:  John Wiley & Sons.

ICRP.   1974.  International Commission on Radiological Protection.
No. 23.  Report of the task group on reference man.  New York:  Pergamon
Press.

Meyer B.  1983.  Indoor air quality.  Reading, MA:   Addison-Wesley
Publishing  Company, Inc.

Mokler  BV, Wong BA, Snow MJ.  1979a.  Respirable partlculates generated
by pressurized consumer products.   I.   Experimental method and general
characteristics.  Am. Ind. Hyg. Assoc.  J. 40(4):330-338.

Mokler  BV, Wong BA, Snow MJ.  1979b.  Respirable particulates generated
by pressurized consumer products.   II.   Influence of experimental
conditions.   Am. Ind. Hyg. Assoc.  J. 40(4):339-347.

Sciarra JJ,  McGinley  P,  Izzo L.  1969.   Determination of  particle size
distribution of selected aerosol cosmetics.   I.  Hair sprays.  J. Soc.
Cosmetic Chemists 20:385-394.

Sciarra JJ,  Stoller L.  1974.   The science  and technology of  aerosol
packaging.  New York, NY:   John Wiley  & Sons,  Inc.

Stahlhofen W,  Eckhard B, Gebhart J,  Heyder  J,  Stuck B.   1980.
Measurement of the extrathoracic,  tracheobronchial  and alveolar
deposition of  aerosol particles in the  human respiratory  tract.
J. Aerosol Science 11(3):234.

Vos OKD, Thomson DB.   1974.   Particle  size  measurement of eight
commercial pressurized products.  Powder  Tech. 10(3):  103-109.

Wells AB, Alexander DJ.   1976.   Determining  resplrable fraction of
aerosols.  Aerosol  Age 21(11):20-24.

                                    143

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144

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                 APPENDIX B




Simmons Market Research Bureau (SMRB)  Reports
                     145

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        APPENDIX B - SIMMONS MARKET RESEARCH BUREAU (SMRB) REPORTS


    The tables Included in this Appendix are a guide to the individual

SMRB reports (volumes) and the products covered by each volume.   The

following are the tables included in this Appendix:


    Table 30.  SMRB reports (1983) by Volume
    Table 31.  Products Listed in SMRB Reports (1983)  by Product Category
                                   146

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            Table 30.   SMRB Reports (1983)  by Volume
 Volume                                   Title
 P-l              .             Automobiles
 P-2                           Cycles,  Trucks,  Vans  & Tires
 P-3                           Automotive Products and Services
 P-4                           Travel
 P-5                           Banking,  Investments,  Memberships,
                              Public Activities  & Contribution
 P-6                           Insurance & Credit Cards
 P-7                           Books, Records,  Tapes,  Stereo & TV
 P-8                           Appliances,  Sewing &  Garden  Care
 P-9                           Home Furnishings & Home Improvements
 P-10                          Sports &  Leisure
 P-ll                          Restaurants, Stores & Grocery Shopping
 P-12                          At  Home Shopping,  Yellow Pages,
                              Florists  & Telegrams
 P-13                          Jewelry,  Wristwatches,  Luggage,
                              Binoculars,  Pens & Pencils and Hen's
                              Apparel
 P-14                          Women's Apparel
 P-l5                          Tobacco Products & Photography
 P-16                          Distilled Spirits  & Mixes
 P-l7                          Malt  Beverages & Wine
 P-18                          Coffee, Tea, Milk, Soft  Drinks,  Juices
                              & Bottled Water
 P-l9                          Dairy Products,  Spreads, Cookies,
                              Desserts,  Baking & Bread Products
 P-20                          Cereals,  Rice, Pasta, Pizza,  Mexican
                              Foods, Fruits &  Vegetables
 P-21                          Soup, Meat, Fish,  Poultry, Condiments
                              & Dressings
 P-22                          Chewing Gum, Candy & Snacks
 P-23                          Soap, Laundry & Paper Products &
                              Kitenet Wraps
P-24                          Household  Cleaners, Room Deodorizers &
                              Pet Foods
P-25                          Health Care Products & Remedies
P-26                          Oral Hygiene Products, Skin Care &
                              Deodorants
P-27                          Hair Care & Shaving Products
P-28                         Women's Beauty Aids,  Cosmetics &
                              Personal  Products & Beauty Salons
P-29                         Games & Toys, Children's & Babies'
                             Apparel  & Specialty Products
P-30                         Relative Volume of Consumption
                             147

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             Table 31.  Products Listed in SMRB Reports (1983)
                            by Product Category
Product Category
Volume
Product
APPAREL - CHILDREN'S &
BABIES'
APPAREL - MEN
APPAREL - WOMEN
(P-29)       Clothing
             Diapers/Cloth, Disposable
             Jeans or Dungarees
             Outerwear
             Shoes
             Sleepwear
             Suitwear
             Underwear

(P-13)       Clothing Bought for a Woman
             Coats
             Jackets
             Jeans & Slacks
             Shirts
             Shoes, Boots & Sneakers
             Sports Apparel
             Suits
             Sunglasses
             Sweaters

(P-14)       Blouses & Shirts
             Clothing Bought for a Han
             Coats
             Dresses
             Hosiery
             Jeans & Slacks
             Lingerie
             Shoes, Boots & Sneakers
             Ski  & Tennis Clothes
             Skirts
             Suits
             Sunglasses
             Sweaters
             Swimsuits
             Warm-up Suits
                                   148

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                           Table 31.  (Continued)
 Product Category
Volume
Product
 APPLIANCES & DURABLES:

 Cal cu 1 ators/Typewr Hers
Household Appliances  &
 Durables
Kitchen Appliances &
 Durables
 (P-8)        Bought in Last 12 Months/For
              Whom/Amount Spent
             Desk Top Calculator
             Pocket or Hand-Held Electronic
              Calculator
             Typewriter, Electric Portable
(P-8)        Bought in Last 12
              Months/Decision Maker
             Air Conditioner, Separate Room
             Burglar Alarm System
             Ceiling Fan
             Electric Air Purifier
             Electric Broom
             Electric Clothes Dryer
             Gas Clothes Dryer
             Grills:  Gas,  Electric,
              Charcoal
             Home Computers,  Brands and Use
             Room Heater,  Portable
             Room Heating System,  Separate
             Room Dehumidifier,  Separate
             Room Humidifier,  Separate
             Sewing Machine
             Smoke/Fire Detector
             Stationary Bicycle
             Videocamera
             Washing Machine,  Automatic
             Water Purifier or Filter

(P-8)         Bought in Last 12 Months/
             Decision  Maker
             Automatic Dishwasher
             Blender,  Electric
             Canning Oars & Lids
             Coffee Maker
             Food Processor, Electric
             Food Dehydrator
             Fry  Pan,  Electric
                                   149

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                           Table  31.   (Continued)
Product Category
Volume
Product
APPLIANCES & DURABLES:

Kitchen Appliances &
 Durables (conf)
Personal Appliances
Power Equipment &
 Hand Tools
(P-8)        Garbage Disposal
             Home Freezer, Separate
             Juicer, Electric
             Metal Cookware Set
             Mixer, Electric
             Oven:
             Microwave
             Self-Clean i ng/Cont i nuous
              -Cleaning
             Pressure Cooker
             Refrigerator, Electric
             Steam Cooker, Electric
             Stove or Range, Electric or Gas
             Trash Compactor, Electric
             Woodburning Stove/Heater

(P-8)        Bought in Last 12 Months/For
              Whom/Amount Spent
             Hair Curler Set, Electric
             Hair Dryer, Bonnet-Type or
              Electric Hand-Held
             Hair Styling Comb, Electric
             Hot  Lather Machine
             Lighted Makeup Mirror
             Shaver, Battery or Electric
             Toothbrush, Electric
(P-8)         Bought in Last  12
               Months/Decision  Maker
             Drill, Electric
             Electric  Router
             Garden Tiller
             Hand Tool  Outfit
             Portable  Workbench
             Power Mower, Electric  or Gas
             Power Yard Trimmer
             Sander, Electric
             Saw:
             Chain, Electric or Gas
             Circular
             Jig/Sabre
             Stationary Radial/Arm
             Snow Blower
             Tractor,  Garden

     150

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                          Table  31.   (Continued)
Product Category
Volume
Product
AT HOME SHOPPING,
YELLOW PAGES, FLORISTS
& TELEGRAMS:                   (P-12)
Hail & Phone Order             (P-12)
             Door-to-Door Sales
             Florists
             Telegrams & Wires

             Auto Accessories
             Recipe Cards
             Cook Books
             Books from Book Club
             Other Books
             Cosmetics
             Records
             Prerecorded Audio Cassette
              Tapes
             Prerecorded Audio Tape
              Cartridges
             Blank Audio Tapes or Cassettes
             Magazines
             Photo Processing
             Fruit,  Cheese or Specialty
              Foods
             Shoes or  Boots
             Clothing
             Needlecraft  Kits & Supplies
             Camping Equipment
             Sporting  Goods  (Such  as
              Fishing  Tackle,  Golf Balls,
              Ski  Poles,  etc.)
             Tools
             Coins (Numismatic)
             Medallions,  Commemorative
             Plates  (Such as  Commemorative
              Medals,  Ingots,  Porcelain,
              etc.)
             Cookware & Kitchen Accessories
             Small Appliances
             Investment Information
             Insurance
             Real  Estate  Information
             Educational Programs
             Trees, Plants, Seeds
             Tupperware Parties
             Vitamins
                                   151

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                           Table 31.   (Continued)
Product Category
Volume
Product
AUTOMOBILES
AUTOMOTIVE PRODUCTS &
SERVICES
(P-l)        Air Conditioning
             Annual Miles Driven
             Automobile Club
             Bought New/Used
             Burglar Alarm in Car
             Car Leasing
             Car Rentals
             Current Auto Ownership
             Current Driver's License
             Decision Makers for One or
              More Cars
             How Purchased
             Where Purchased
             Insurance
             Makes & Models of Cars
              Owned/Domestic, Imported
             Model Type/Size
             Model Year Owned
             Next Car Purchase
             Radio/Tape Player
             Type of Car (Body Style)
             Type of Drive & Diesel Engine
             When Acquired
(P-3)         Air Filters
             Antifreeze
             Brake Linings/Pads
             Car Batteries
             Car Wax & Polish
             Gasoline & Diesel  Fuel
             Gasoline Additives
             Motor Oil
             Motor Oil Additives
             Mufflers
             Oil Filters
             Rustproofi ng
             Shock Absorbers
             Spark Plugs
             Transmission Services
                                    152

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                           Table 31.   (Continued)
 Product  Category
Volume
Product
BANKING,  INVESTMENTS,
MEMBERSHIPS, PUBLIC
ACTIVITIES & CONTRIBUTIONS
BEAUTY AIDS,
BEAUTY SALONS,
COSMETICS & PERSONAL
PRODUCTS - WOMEN
(P-5)        Accounting Services
             Auto Loans
             Brokerage Account
             Checking Accounts
             Farm Ownership
             Gold/Silver
             I.R.A.  or Keogh Plan
             Memberships
             Mortgages
             Now Accounts
             Personal Loans
             Public  Activities
             Contributions to Public TV
             Retirement & Investment
             Property
             Safe Deposit Boxes
             Savings Accounts
             Savings Certificates
             Securities
             Treasury Bills
             Trust Agreements
             Vacation/Weekend Homes
(P-28)        Bath & Shower Additives
             Beauty Salons
             Blusher
             Cotton Balls or  Squares
             Eye Liner
             Eye Shadow
             Face Powder/Loose, Pressed
             Facial  Moisturizers, Cleansing
             Creams & Lotions
             Feminine Hygiene Douches,
             Suppositories & Spray
             Deoderants
                                   153

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                           Table 31.   (Continued)
 Product  Category
Volume
Product
DISTILLED  SPIRITS  & MIXES      (P-16)
             Alcoholic Beverages
             Blended Whiskey or Rye
             Bourbon Whiskey
             Brand Influence of What Served
              in Home
             Brandy & Cognac
             Canadian Whiskey
             Cordials & Liqueurs
             Gin
             Irish Whiskey
             Prepared Cocktail
              Mixes with Liquor
             Purchase Distilled Spirits by
              the Case
             Rum
             Scotch Whiskey
             Tequila
             Vodka
FLOWER, VEGETABLE,
LAWN SEED & FERTILIZER
GAMES & TOYS
(P-8)         Bought in Last 12
              Months/Amount Spent
             Fertilizers
             House Plant Food,  Lawn
             Vegetable Garden,  Other
              Seed
             Flower,  Lawn,  Vegetable

(P-29)        Bought in Last 12
              Months/Amount Spent
             Video & Non-Video  Electronic
              Games
                                   158

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                           Table 31.   (Continued)
 Product Category
Volume
Product
HAIR  CARE  PRODUCTS
HEALTH CARE  PRODUCTS
& REMEDIES
(P-27)       Creme Hair Rinses
             Hair Coloring Products
             Hair Conditioners
             Hair Sprays
             Hair Tonics or Dressings
             Home Permanents
             Shampoos

(P-25)       Adhesive Bandages
             Asthma Relief Remedies
             Athlete's Foot Remedies
             Cold, Allergy & Sinus Remedies
             Cough Drops & Syrup
             Diet Control  Products
             Eyeglasses & Contact Lenses
             Headache Remedies & Pain
              Relievers
             Illnesses & Ailments
             Indigestion Aids & Upset
             Stomach Remedies
             Laxatives
             Medicated Throat Lozenges
             Nasal Sprays
             Pain Relieving Rubs & Liquids
             Suntan & Sunscreen Products
             Throat Lozenges/Medicated
              Vitamins
HOME FURNISHINGS &
HOME IMPROVEMENTS
(P-9)         Clocks:   Wall,  Mantle,  Desk
             Standing
             Dinner & Tableware
             Glassware
             Crystalware
             Fine  China
             Flatware
             Other Dinnerware
             Fluorescent & Incandescent
             Lighting
             Home  Furnishings & Household
              Durables
                                   159

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                          Table 31.   (Continued)
Product Category
Volume
Product
HOME FURNISHINGS &
HOME IMPROVEMENTS (conf)      (P-9)
             Beds/Other Bedroom Furniture
             Blankets, Electric/Other
             Comforters/Quilts
             Curtains & Draperies
             Dining Room Furniture
             Mattresses
             Pianos & Organs
             Telephones & Telephone
             Answering Machines
             Pillowcases
             Sheets
             Towels
             Home Improvements
             Bathroom Plumbing
             Carpeting
             Fixtures
             Flooring
             Flue Dampers
             Fireplaces
             Furnace
             Garage Door Opener
             Hot Tubs/Whirlpools
             Hot Water Heater
             House Plans Purchase
             Insulation for  Ceiling,  Floor
              or Wall
             Kitchen Cabinets  & Sinks
             Outdoor & Indoor  Lighting
             Outdoor Deck/Porch/Patio
             Roofi ng
             Siding
             Storm Doors or  Windows
             Solar Heating/Solar Hot  Water
             Thermostats
             Wall  Paneling
             Wallpaper
             Weather Stripping
             Interior  & Exterior Remodeling
             Paints & Stains
             Exterior
             Interior
                                   160

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                           Table 31.  (Continued)
 Product Category
Volume
    Product
 HOUSEHOLD CLEANERS & ROOM
 DEODORIZERS                   (P-24)
INSURANCE & CREDIT CARDS
(P-6)
JEWELRY, BINOCULARS,
WRISTWATCHES, PENS &
MECHANICAL PENCILS
(P-13)
 Air Fresheners & Deodorizers
 AlIfPurpose Cleaners
 Bug Traps
 Drain Cleaners
 Floor Waxes
 Furniture Polishes
 Glue & Bonding Agents
 Insecticides
 Oven Cleaners
 Rug Cleaners & Shampoos
 Rug Deodorizers & Fresheners
 Scouring  Pads  & Sponges
 Scouring  Powders
 Termite & Rodent Control
 Toilet Bowl  Cleaners
 Window &  Glass Cleaners

 Credit Cards
 18  Credit Type Listings
 How Billed or  Printed
 Used in Last 30 Days
 Home Owners/Personal Property
 Insurance
 Life Insurance
 Medical,  Hospital, Health
 Insurance
 Other  Types
Jewelry
Costume
Diamond
Gold
Other Jewelry and Gems
Pens & Mechanical Pencils
 Bought for Self or Someone Else
Wristwatches/Men
Wri stwatches/Women
                                   161

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                           Table 31.   (Continued)
Product Category
Volume
Product
LUGGAGE

HALT BEVERAGES & WINES
(P-13)       Luggage or Baggage

(P-17)       Alcoholic Beverages
             Ale
             Beer
             Domestic Light/Low-Calorie
             Domestic Regular
             Draft
             Imported
             Malt Liquor
             Wine
             Aperitif & Specialty
             Champagne, Cold Duck &
              Sparkling Wines
             Light Domestic Dinner/Table
             Domestic Dinner/Table
             Imported Dinner/Table
             Port, Sherry & Dessert
             Sangri a/Pop/Party
             Vermouth
MOTORCYCLES, SCOOTERS,
MINICYCLES & BIKES,
NOPEDS & MOPEDS
(P-2)         Minicycles,  Minibikes,  Mopeds,
              Nopeds,  Motorscooters
             Any Owned in Household
             Decision  Maker for Make
             Bought  -  Type Owned
             Most Recent  Bought,  New/Used
             Type Owned by Household
             Motorcycles
             Bought  New/Used
             Decision  Maker for One  or  More
             Motorcycles
             Engine  Size
             Motorcycles  Owned  in Household
             Number  Owned by Household
              Members
             Type Owned
                                   162

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                           Table 31.   (Continued)
Product Category
Volume
Product
ORAL HYGIENE PRODUCTS,
SKIN CARE & DEODORANTS
PET FOODS, FLEA &
TICK CARE PRODUCTS
(P-26)       Breath Fresheners
             Denture Cleansers
             Deodorants & Antiperspirants
             Hand & Body Creams, Lotions, or
              Oils
             Medicated Skin Care Products
             Mouthwash
             Toothbrushes
             Toothpaste
(P-24)        Cat Ownership
             Cat Food
             Canned
             Packaged Dry
             Packaged Hoist
             Dog Ownership
             Dog Food & Mixing  Dog  Food
             Types
             Canned
             Packaged Dry
             Packaged Moist
             Flea & Tick  Care Products for
             Dogs  &  Cats
             Decision Makers for Brands of
             Dog & Cat Food (7 Different
             Types)
                                   163

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                           Table  31.   (Continued)
Product Category
Volume
Product
PHOTOGRAPHY
RESTAURANTS, STORES &
GROCERY SHOPPING
SEWING
SHAVING PRODUCTS
(P-15)       Cameras/Movie, Still
             Film & Flash Equipment
             Film Processing
             Projectors, Movie, Slide
(P-11)       Cents-Off-Coupons
             Catalogue Showroom, Department
              A Discount Stores
             Shopped in Last 3
              Months/Amounts Spent in Last
              30 Days
             Fast Food/Drive-in
             Family & Steak House
             Restaurants
             Gourmet & Health Food
             Specialty Stores
             Grocery Shopping Expenditures
             Supermarket & Food Shopping
             Supermarkets & Convenience
              Stores

(P-8)        Finished Garments in Last 12
              Months
             General Sewing or Mending in
              Last 12 Months
             Sewing Materials & Notions
             Sewing Patterns/Brands
             Sewing Offers from Magazines

(P-27)       After Shave Lotion & Cologne,
              Use & Gift Purchases
             Depilatories
             Pre-Electric Shave Lotion
             Razor Blades
             Shavers/Disposable,  Electric &
              Battery
             Shaving Cream or Gel
                                    164

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                           Table  31.   (Continued)
Product Category
Volume
Product
SOAP, LAUNDRY & PAPER
PRODUCTS/KITCHEN WRAPS
SOUP, HEAT, FISH, POULTRY,
CONDIMENTS & DRESSINGS
(P-23)       Aluminum Foil
             Automatic Dishwashing Detergent
             Bleach
             Dishwashing Liquid
             Disposable Cups & Dispenser
             Fabric Softeners
             Facial Tissues
             Laundry Pre-Soaks &
              Pre-Cleaners
             Laundry Washloads
             Liquid Toilet Soaps
             Paper Plates
             Paper Towels
             Plastic Garbage Bags & Trash
              Liners
             Plastic Sandwich or Food Bags
             Plastic Type Kitchen Wraps
             Reusable "Cloth" Towels
              (Non-Woven)
             Soaps & Detergents
             Toilet Paper
             Toilet Soap
(P-21)        Bacon
             Barbecue & Seasoning Sauces
             Beef
             Bouillon Cubes
             Canned Chicken
             Canned Heat Spreads
             Canned Soup
             Canned Tuna
             Catsup
             Coating & Stuffing Products
             Cold Cuts
             Cooking Spray
             Corn Syrup
             Corned Beef
                                   165

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                          Table 31.   (Continued)
Product Category
Volume
Product
SOUP, MEAT, FISH, POULTRY,
CONDIMENTS &
DRESSINGS (cont1)
(P-21)       Corned Beef Hash
             Deviled Ham
             Dry Soup/Lunch Mix
             Cornish Game Hen (Fresh/Frozen)
             Frankfurters:  Beef,  Chicken &
              Turkey
             Fresh Fish/Shell Fish
             Fresh Breast of Turkey
             Other Fresh Turkey
             Frozen Dinners & Courses
             Frozen Fish/Shell  Fish
             Frozen Prepared Seafood
             Fresh Chicken
             Frozen Breast of Turkey
             Frozen Pre-Stuffed Turkey
             Other Frozen Whole Turkey
             Frozen Fried Chicken
             Other Frozen Chicken
             Honey & Fructose
             Mayonnai se
             Mustard
             Meat Tenderizer
             Lamb
             Pancake & Table Syrup
             Pork
             Pork Sausage
             Salad & Cooking Oil
             Salad Dressings
             Sugar
             Veal
             Vienna Sausage
             Stews
             Canned Ham
             Roast Beef  Hash
                                   166

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                          Table 31.   (Continued)
Product Category              Volume          Product
TRUCKS, VANS & SPORT/
UTILITY VEHICLES              (P-2)        Any Owned in Household
                                           Bought to Replace Car/Truck
                                           Decision Maker for Hake Bought
                                           - Type Owned
                                           Most Recent Bought New/Used by
                                            Type
                                           Model Year for Types Owned
                                           Most Recent Bought
                                           By 4-Wheel Drive & Diesel
                                           Engi ne
                                           By Type
                                           Primary Purpose Used for
                                   169

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170

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               APPENDIX  C

An Alphabetical Listing of Variables Used
              1n This  Volume
                   171

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            Table 32.  An Alphabetical Listing of Variables Used in this Volume
Variable
Definition
Units
ADD      Annual.dermal dose                                        mass/year

ADF      Amount of product or  residue deposited on fabric surface  mass/area

AR       Rate of application of film or coating to surface         area/time

AV       Area of skin surface  exposed                              area

C        Concentration of chemical substance in air at any point   mass/volume
         in time during exposure

CA^      Concentration of air  at  liquid/gas film interface         moles/volume

CB]      Concentration of chemical substance at liquid/gas         moles/volume
         film interface

Co       Initial concentration  of chemical substance in air       mass/volume
         as a result of an instantaneous release

WCS      Concentration difference of chemical substance            mass/volume
         across specified tissue

Cso      Initial concentration of migrant in polymer               mass/volume

Cta      Concentration of the  chemical substance at the time       mass/volume
         at the end of application of film or coating

Ctg      Concentration of the chemical substance at the time       mass/volume
         at the end of its continuous release

Ctr      Concentration of the chemical substance at the time       mass/volume
         at the end of release of all substance from the
         coating

D        Diffusion coefficient of migrant through polymer          mass

DA       Dust adherence to skin                                    mass/area

DAB      Diffusion coefficient of chemical  substance in air at     area/time
         25°C and 1 atmosphere
                                   172

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                         Table 32.  (continued)
Variable
DEX
OIL
DSY
OU
°W
F
FA
FA
FQ
G

QN
GNAR
IHX
IHXG
IHXp
ING
IR
Js
k
Definition
Annual dermal exposure
Dilution fraction
Density of product
Duration of exposure to consumer product
Diffusion coefficient in water
Fraction of migrant released from polymer
Fraction of spilled material entrained in air
Fraction of chemical substance absorbed
Frequency of exposure on an annual basis
Rate of release of chemical substance from consumer
product
Mass flux of chemical substance
Time-dependent release rate
Annual inhalation exposure
Annual exposure to inhaled particulates that enter
the gastrointestinal tract
Annual exposure to inhaled particulates that enter the
pulmonary region
Annual ingest ion exposure
Inhalation rate
Permeation rate (flux) of chemical substance
A constant that is a product of the mixing factor, m,
Units
mass/year
unitless
mass/ volume
time
area/time
unitless
unitless
unitless
unitless
mass/time

mass/area-time
mass/time^
mass/ year
mass/year
mass/year
mass/year
volume/time
mass/area-time
unitless
and the air exchange  rate, Q/V
                          173

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                                   Table 32.   (continued)
Variable
Definition
Units
Kp       Permeability constant

L        Thickness of gas film or polymer

LR       Leaching rate of chemical substance from object placed
         in mouth to saliva

LUS      Fraction of liquid used in the mouth that is swallowed
         unintentionally

M        Mass of consumer product spilled, sprayed, applied, or
         used in any other manner

m        Mixing factor

MA       Molecular weight of air

MB       Molecular weight of chemical substance

Mt       Mass of migrant released from polymer

MW       Molecular weight of chemical substance

N        Molar flux of pure chemical  substance

NRF      Nonrespirable fraction (e.g., weight fraction of all
         inhaled particles deposited in the head or
         tracheobronchial region)

0V       Fraction of product that is overspray (e.g., does not
         contact intended surface)

P        Vapor pressure of chemical  substance at 25°C

PA^      Partial pressure of air at interface of liquid and
         main air stream

PA2      Partial pressure of air at interface of gas film and
         main air stream
                                          volume/area-time

                                          length

                                          mass/time/area


                                          unitless


                                          mass


                                          unitless

                                          dimensionless

                                          dimensionless

                                          mass

                                          dimensionless

                                          moles/area-time

                                          unitless



                                          unitless


                                          atmospheres

                                          atmospheres


                                          atmospheres
                                   174

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                                  Table 32.  (continued)
Variable
                         Definition
      Units
PB2


POE


Q

R

RF



SA

SAO

T

T

ta

TOE


TDF


te

TF
         Partial pressure of chemical  substance at interface
         of liquid and main air stream

         Partial pressure of chemical  substances at interface
         of gas film and main air stream

         Fraction of inhaled particles subject to pulmonary
         deposition

         Ventilation  air flow rate

         Universal  gas constant

         Respirable fraction (e.g., weight fraction of all
         inhaled particles deposited in the pulmonary air
         space

         Surface area covered by film  or coating

         Surface area of object being  place in mouth

         Film thickness of liquid on skin surface

         Temperature

         Time at the end of application

         Fraction of inhaled particles deposited in the
         respiratory tract

         Total  deposition fraction (e.g.,  weight fraction of
         inhaled particles deposited in the respiratory tract)

         Time at the end of exposure

         Fraction of residue/dye transferred to the skin  per
         exposure event

         Time at the end of release of chemical  substance
 atmospheres


 atmospheres


 unitless


 volume/time

 atm-cm3/mole-°K

 unitless



 area

 area

 length

 degrees

 time

 unitless


 unitless


 time

unitless


time
                                   175

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                                  Table 32.   (continued)
Variable                 Definition                                     Units
to         Time at the beginning of exposure                          time

tr         Time at the end of release of all volatile chemical        time
           substance from a film or coating applied to a
           surface

V          Room volume                                                volume

VA         Molar volume of air                                        volume/mole

V[J         Molar volume of chemical substance at its normal           volume/mole
           boiling point

Vs         Volume of polymer                                          volume

WF         Weight fraction of chemical substance in consumer          unitless
           product

WV         Workspace volume                                           volume
                                   176

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                APPENDIX D



Average Body Weights of Humans by Age Group
                    177

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          Table 33.   Average Body Weights of Humans by Age Group3
           Age Group                                Body Weight
                                                    (kilograms)
    Adults, age 18-74                                   71.8
    Adult males, age 18-74                              78.1
    Adult females, age 18-74                            65.4
    Child-bearing females, age 18-44                    64.0
    Child, less than 3 years old                        11.6
    Child, age 3-6                                      17.4
    Child, age 6-9                                      25.0
    Child, age 9-12                                     36.0
    Child, age 12-15                                    50.6
    Child, age 15-18                                    61.2
a
 Average values adapted from Anderson et al. (1984).
                                   178

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              APPENDIX E

Derivation of Equations for Estimating
 Concentrations  of Chemical  Substances
             in  Indoor  Air
                 179

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                                APPENDIX E
    The derivation of equations for estimating concentrations of chemical
substances in indoor air at any point in time, t, as a result of a
time-dependent release are presented for four intervals.  These are:

    (1 )  0 < t < t1 ;

    (2)  ^ < t < t2;

    (3)  t2 < t < tr; and

    (4)  t > tr.

The parameters, t] and t2, can represent the time to apply the liquid
film to a surface from which a chemical  substance volatilizes (ta) or
the time required for a chemical substance to evaporate from a liquid
film once it has been applied to a surface (tg).   If ta is smaller
than tg, then ti equals ta and t2 equals tg.  If  tg is
smaller than ta, then t-] equals tg and
parameter, tr, 1s the sum of t] and t?.
(1) For t < ti
g.      g
equals ta
                                                      The
    The mass balance equation and the physical  interpretation of  each
group of terms is
                          v     = GNAR t - mqc.
                          (E-l)
   {The net mass of    \   (The mass of chemical)   (The  mass  of  chemical
   chemical substance j. = < substance released   >-< substance removed  by
   in air 1n the room)   (to air in the room  )   (air  leaving  the  room

Upon dividing Equation (E-l) by V, Equation (E-l)  becomes
                            dt
By letting
                                                                    (E-2)
                             - mQ and k? -
                               V             V
                                   180

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and  substituting k] and k2 as appropriate into Equation  (E-2),  the
resulting expression is

                                        kiC.                         (E-3)
By letting

                              z = k2t - k^,                         (E-4)

and by differentiating with respect to time, the resulting expression  is
                                                                    (E-5)
By rearranging Equation (E-5), Equation (E-6) is

                            dC   -1 /dz   .
When Equation (E-6) and Equation (E-4) are substituted into Equation
(E-3), the resulting expression is
When Equation (E-7) is multiplied by k] and rearranged, the resulting
expression is

                             jjf = -kiz + k2.                        (E-8)
Equation (E-8) can be rearranged to

                                 dz
                                       = dt.                        (E-9)
Multiplying Equation (E-9) by k2 yields
When Equation (E-10) is integrated, the resulting expression is

                        -kp   /    ki   \
                        __£ In 1 - — z = k2t + C*.                 (E-ll)
                         k]   \    k2  '
                                    181

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When C  = 0 at  t  = 0, this  implies that  z  = 0 at t = 0 and that C* = 0.
Setting C* = 0 and dividing  Equation  (E-ll) by (-k2/k]) yields


                           In | 1 - !lL z | = -k-)t.                    (E-12)
Taking the antilog of Equation  (E-12) yields
                                                                    (E-13)
Substituting the expression from Equation (E-4) for z Into Equation
(E-13) and rearranging yields
By solving for C, the resulting expression is


                       C = -1 k
                                         M- k2t]
                                           /      J
which, upon rearranging, Is
C =
                                   1  - e'^1-  - t
Substituting GNAR/V for k2 yields
                        c .
                                                                    (E-14)
                                            (E-15)
                                                                    (E-16)
                                            (E-17)
The Equation to calculate the average concentration for any interval of
time where the time at the end of exposure is less than or equal  to t-\
is obtained by integrating Equation (E-17) with respect to time and
dividing the resulting equation by the length of the exposure interval.
The resulting expression is
               -ave -
GNAR
klV(tb - te)
> _ t _ e^l*"
2 k]
2
                                                  It =
                                                  -It = t,
                                                                    (E-18)
                                    182

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where

    tjj = time at the beginning of the desired time Interval
    te =' time at the end of the desired time interval.
(2) For t-| < t < t2


    The mass balance equation and the physical Interpretation of each
group of terms Is


                         V jj£ = GNARt! - mQC.                       (E-19)


  (The net mass of   \   (The mass of chemical )   (The mass of chemical
  
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Solving for C by dividing by  -k2/k-| yields
                               "1
                        Inll -  j— C  1= -kit + C*.                   (E-25)
                          V     2   /
Taking the antilog of Equation (E-25) yields

                               ki         -kit
                           1 - £- C  = C* e    .                     (E-26)


To determine C*, substitute the expression for C in Equation (E-17) for
the parameter, C, in Equation (E-26).  Substitute ti for the parameter,
t, in Equation (E-17).  The resulting expression after these
substitutions are made  is
                    K! GNAR/     1    «
                1 - td-TTwlti - r- + -TT— Jl= C*e     .          (E-27)
GflAR/k-|V 1n Equation (E-27) can be simplified If one multiplies by
t-|/t-|.  The parameter k2 can be substituted for
after which Equation (E-28) Is obtained:
Equation (E-28) can be simplified to Equation (E-29) by cancelling like
terms:
                                                                    (E-29)

Multiplying Equation (E-29) by e ^ 1 and cancelling like terms yields


                     kltl   -     --- - e.  .   ) = C*.             (E-30)
                                           kit]  /
Equation (E-30) can be further simplified to Equation (E-31).
                                    184

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 or
                          C* =
                               kit]
                                                                    (E-32)
Substituting the expression for C* 1n Equation (E-32) for C* 1n Equation
(E-26) yields
                   C =
                       -k2
                           LL
                           [kit-
e    - 1   e
                        kijkiti

Multiplying Equation (E-33) by -1 and rearranging yields
                      k2
                  C = 7-
                                            - e
Substituting
                      for k2 in Equation (E-34) yields

or
                       k-|V
                              - r~\e
- e
                  ")
Simplifying Equation (E-36) yields
                    C =
                        GNAR
Rearranging Equation (E-37)  yields


                        GNAR I"     e
                    C = T7w ti  -  -
                                                 "1
                       (E-33)
                                                                    (E-34)
                                                                    (E-35)
                                                                    (E-36)
                                                                    (E-37)
                                                                    (E-38)
The equation to calculate the average concentration  for  any  Interval  of
time less where te Is less than or equal  to  t2  and t^  Is  greater
than or equal to t]  Is obtained by Integrating  Equation  (E-38) with
respect to time and  dividing the resulting equation  by the length  of  the
exposure Interval.  The resulting expression Is
                                   185

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             Cave
(3) For t2 < t < tr
   MR

MV(te-tb)
                               tit
                                                         t=t<
                                                         t=tb
                    (E-39)
    The mass balance equation and the physical Interpretation of each
group of terms Is
                           j «
                         V    = GNAR (tr-t) - mQC.
                                                                    (E-40)
  (The net mass of
  jchemlcal substance
  (in air In the room
                          The mass of chemical
                          substance released
                          to air 1n the room
   The mass of chemical
- ^ substance removed by
   air leaving the room
Dividing Equation (E-40) by V yields
                          dC
                                             mQ
By letting
                          dt •
                               mQ
                          k] =  - and
                                                                    (E-41)
and by substituting k-j and k2, as appropriate, into Equation (E-41),
one obtains
                          dC.
                          dt
                             = k2(tr-t) - kiC.
                    (E-42)
If we let

                           z = k2(tr-t)  - k^                       (E-43)

and differentiate with respect to time,  the resulting expression is
                            dt = ~k2 ' kl  df

Upon being rearranged,  Equation (E-44) becomes
                                          dC
                                          dt"
                                                                    (E-44)
                                                                    (E-45)
                                   186

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 If  Equations  (E-43) and  (E-45) are  substituted  into  Equation  (E-42),  the
 resulting  expression  is
                                         =  z.                        (E-46)
Multiplying  Equation (E-46) by -k-| yields
                             jjf + k2 = -kiz.                         (E-47)
Rearranging  Equation (E-47) yields
                            |jf = -(k2 + kiz).                        (E-48)
Rearranging  Equation (E-48) yields
                             k2 +d^z = -dt.                         (E-49)
Integrating  Equation (E-49) with respect to
                       £- In (k2 + kiz)  = -t * B".                  (E-50)
Multiplying  Equation (E-50) by ki  yields
                        In (k2 + kiz) =  -kit * B1.                  (E-51)
If one takes the antilog of Equation (E-51), the resulting expression is
                            k2 + kiz = Be"klt.                      (E-52)
To determine B in Equation (E-52),  substitute the expression for z from
Equation (E-43) in Equation (E-52).   When t equals t2,  C is equal  to
Ct2.  Therefore, substitute t2 for  t and Ct2 for C to determine B.
Ct2 is calculated by substituting  t2 for t  in Equation  (E-37).   The
resulting expressing is
             k2 + k-)  k2 (tr-t2)  - kiCt2  = Be~.                  (E-53)
Rearranging Equation  (E-53)  yields
                                         =
                                   187

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6 =
                            k-,k2  (tr-t2)  -  h2  Ct2].
                                                                     (E-54)
Substituting the expression for z from Equation  (E-43)  into  Equation

(E-52) yields
                   k2 + k!k2 <2 (tr-t)].                                     (E-58)


Simplifying Equation (E-58) results in



              -k-|2C = e(~klt + klt2)rk2 + k!k2 (tr-t2)  - k2 Ct2l


              -[k2 + k-,k2 (tr-t)].                                   (E-59)


Simplifying Equation (E-59) results in


                    .     -k-,(t-t2)r                      .    -I
                 -k-]2c = e  '       I k2 + k-|k2  (tr-t2) - k12ct2J


                 -Tk2 * k]k2 (tr-t)l.                                (E-60)



Dividing Equation (E-60) by -k-)2 yields


                           :t-t2)
                   C = e
                                   - — •?- — (tr-t2) + ct2
                                     ^1   k]
                             Kl
                                (tr-t)
                                                                    (E-61)
                                    188

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Substituting
                    for k2 in Equation (E-61)  and  rearranging  yields
                         -kl(t-t2)
                       -e
                                   GNAR  GNAR
                                              :tr-t2) -
                     GNAR  GNAR
                                                                    !E-62)
    Is calculated using Equation (E-38)  by  setting  t  equal to t2.  The
equation to calculate the average concentration  for any  interval of time where
te is less than or equal  to tr and t^  is  greater  than or equal to t2
is derived by integrating Equation (E-62) with respect to time and dividing
the resulting equation by the length of  the  exposure  interval.  The resulting
expression is
1
ave -
GNAR
k-|2v
(te-tb)
GNAR
k]V
-Mt-t2)
e
tr-| >

t=t
t=t
GNAR
e
b
                                             + TT (tr-t2) - Ct2
                                                                   (E-63)
(4) For t > tr

    Equation (3-7)  with  Ctr  substituted for C0 and with (t-tr)
substituted for t is  used  to calculate the concentration at any time after
tr.  Ctr is calculated by  substituting tr for t in Equation (E-62).   As
the time during this  Interval  increases, the concentration decreases
exponentially as air  containing  the chemical flows out of the room.
                             C  = Ct
                                  Je-m(Q/V)(t-trj]
                               (E-64)
The equation to calculate  the average concentration for any interval  of  time
where te and tb are  greater  than or equal to tr is derived by
integrating Equation (E-64)  with respect to time.  The resulting expression  is
                          Cave  =
f  -k(t-tr)]t=te
r~**~H
L          Jt=tb
                                                                  (E-65)
                                   189

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