EPA-450/2-77-029
October 1977
(OAQPSNo. 1.2-071)
                     GUIDELINE SERIES
                       GUIDELINE
             FOR DEVELOPMENT
      OF CONTROL STRATEGIES
      IN AREAS WITH FUGITIVE
                 DUST PROBLEMS
  U.S. ENVIRONMENTAL PROTECTION AGENCY
       Office of Air and Waste Management
    Office of Air Quality Planning and Standards
   Research Triangle Park, North Carolina 2771 1

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                              EPA-450/2-77-029
                            (OAQPS No. 1.2-071)
GUIDELINE FOR DEVELOPMENT
    OF CONTROL STRATEGIES
    IN AREAS WITH FUGITIVE
         DUST PROBLEMS
           Monitoring and Data Analysis Division
        U.S. ENVIRONMENTAL PROTECTION AGENCY
           Office of Air and Waste Management
          Office of Air Quality Planning and Standards
          Research Triangle Park, North Carolina 27711

                 October 1977

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                                  OAQPS GUIDELINE SERIES

The guideline series of reports is being issued by the Office of Air Quality Planning and Standards (OAQPS)
to provide information to state and local air pollution control agencies; for example, to provide guidance
on the acquisition and processing of air quality data and on the planning and analysis requisite for the
maintenance of air quality. Reports published in this series  will he available - as supplies permit • from
the Library Services Office (MD-35), Research Triangle Park., North Carolina 27711; or, for a nominal fee,
from the National Technical  Information Service. 5285 Port Royal Road, Springfield, Virginia 22161.
This report, based on a study by TRW, Inc., Redondo Beach. California, was furnished to the Environ-
mental Protection Agency in fulfillment of Contract No. 68-01-3152. Prior to final preparation, the report
underwent extensive review and editing by the Env ironmental Protection Agency. Subject to clarification
and procedural changes, the contents reflect current Agency thinking.
The mention of trade names or commercial products does not constitute endorsement or recommendation
for use by the Environmental Protection Agency.
                                 Publication No. EPA-450/2-77-029
                                  (OAQPS Guideline No. 1.2-071)

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                           TABLE  Oh  CONTENTS

                                                                 Page

1.0  INTRODUCTION	1-1
     T.I   BASIC DEFINITIONS 	   1-2
     1.2   SUMMARY OF PROCEDURES FOR DEVELOPMENT OF CONTROL
          STRATEGIES FOR FUGITIVE DUST	1-4
2.0  ANALYSIS OF AIR MONITORING DATA	2-1
     2.1   MONITOR SITE SURVEYS	2-1
     2.2   NATURE AND EXTENT OF THE TSP PROBLEM	2-9
     2.3   AIR QUALITY DATA ANALYSIS	2-11
3.0  EMISSION INVENTORIES AND PROJECTIONS 	   3-1
     3.1   ESTIMATION OF BASEYEAR ANTHROPOGENIC FUGITIVE
          DUST EMISSIONS	3-3
          3.1.1  Motor Vehicles on Unpaved Roads	3-3
          3.1.2  Entrainment of Street Dust	3-8
          3.1.3  Construction Activities  	   3-9
          3.1.4  Agricultural Tilling Operations	3-14
          3.1.5  Off-Road Motor Vehicles	3-19
          3.1.6  Unpaved Parking Lots and Truck Stops	3-20
          3.1.7  Aggregate Storage Piles	3-21
3.2  ESTIMATION OF BASEYEAR WIND EROSION EMISSIONS	3-23
          3.2.1  General Methodology	3-24
          3.2.2  Soil Erosion Emissions from Specific
                 Source Categories  	   3-25
3.3  PROJECTION OF FUGITIVE DUST EMISSIONS	3-38
          3.3.1  Anthropogenic Sources	3-38
          3.3.2  Wind Erosion Sources	3-43
4.0  EMISSIONS/AIR QUALITY RELATIONSHIP 	   4-1
     4.1   SOME FACTORS AFFECTING SELECTION OF THE
          SOURCE-RECEPTOR RELATIONSHIP  	   4-1
          4.1.1  Averaging Time	4-1
          4.1.2  Source Configuration 	   4-2
     4.2  DESCRIPTIONS OF SUGGESTED AIR QUALITY MODELS  ....   4-3
          4.2.1-  AQDM and COM	4-4
          4.2.2  The Atmospheric Transport and Diffusion
                 Model	4-4
                                   111

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                       TABLE OF CONTENTS  (cont'd.)

          4.2.3  Hanna-Gifford Model  	   4-6
          4.2.4  Modified CDM/Rollback Model  ...  	   4-7
     4.3  SUMMARY	4-9
5.0  ALTERNATIVE CONTROL MEASURES  	   5-1
     5.1  CONTROL OF DUST FROM UNPAVED ROADS	5-1
     5.2  CONTROL OF ENTRAINED STREET DUST	5-10
     5.3  CONTROL OF DUST EMISSIONS FROM  CONSTRUCTION  AND
          DEMOLITION ACTIVITIES	5-16
     5.4  CONTROLS FOR AGRICULTURAL DUST  EMISSIONS  	   5-20
          5.4.1  Continuous Cropping 	   5-20
          5.4.2  Crop Residue and Modified Tilling
                 Operations	5-21
          5.4.3  Limited Irrigation of Fallow Melds	5-23
          5.4.4  Windbreaks and Stripcropping	5-23
          5.4.5  Chemical Soil Stabilizers	5-24
     5.5  CONTROL OF TAILINGS PILES	5-25
     5.6  CONTROL OF UNPAVED PARKING LOTS AND TRUCK STOPS.  .  .   5-27
     5.7  CONTROL OF EMISSIONS FROM DISTURBED SOIL.
          SURFACES	b-27
6.0  INTEGRATION OF FUGITIVE DUST SOURCE IMPACTS INTO
     THE STATE IMPLEMENTATION PLANNING PROCESS 	   6-1
     6.1  INTRODUCTION	6-1
     6.2  EVALUATION OF CONTROL STRATEGY 	   6-2
          6.2.1  Impact of Control Strategy on Emission
                 Levels	f>-2
          6.2.2  Cost of Strategy	6-3
     6.3  GUIDES FOR THE SELECTION OF REASONABLE CONTROL
          MEASURES	6-4
     6.4  IMPLEMENTATION ASPECTS  	   6-6
          6.4.1  Demonstration Project 	   6-8
     6.5  CONCLUSION  	  .....   6-10
 APPENDIX A	A-l
 APPENDIX B.   DETAILED DESCRIPTION OF THE HANNA-GRIFFORD
               MODEL	B-l
 APPENDIX C.   MODIFIED CDM/ROLLBACK MODEL   	   C-l
 APPENDIX D.   INFORMATION REQUIRED AS INPUT TO THE
               CDM/ROLLBACK MODEL  	   D-l
 APPENDIX E.   SAMPLE APPLICATION OF THE  CDM/ROLLBACK
               MODEL	E-l
 REFERENCES	F-l

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                           1.0  INTRODUCTION
     The purpose of this document is  to outline a methodology for development of
control  strategies for areas experiencing nonattainment problems due to fugitive
dust emissions.   Historically, relatively little attention has been focused on
control  of fugitive dust sources.  Awareness of the nature and extent of these
sources  has been very limited, and potential dust control  measures have not been
generally implemented.  As the extent of the fugitive dust problem has become
evident, more effort is now being applied to characterize  dust sources and to
develop  methods for their control.  This document synthesizes the results of
these recent efforts and establishes an overall procedural method for the devel-
opment of air programs to control high TSP levels caused by fugitive dust.
However, this document does not address the various policy issues associated
with fugitive dust control such as definition of those areas where control plans
should be developed or new source review as outlined in the Fugitive Dust Policy
Paper dated August 1, 1977.
     Many states are now facing the problem of controlling fugitive dust.
Previously, it was routinely believed that fugitive dust emissions were unavoid-
able.  However, recent studies show that while some fugitive dust emissions are
mainly a result of natural phenomena, most frequently fugitive dust sources
result directly from or during human activity.  In this sense, most fugitive
dust sources are controllable although the extent of control required for attain-
ment of  the National Ambient Air Quality Standards (NAAQS) may impose unreason-
able demands.
     Before control strategies can be systematically formulated and evaluated,
essential and basic technical analyses must be performed.   Chapters 2, 3, and
4 summarize the analytical foundation for the strategy development process.
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Subjects discussed in these chapters  include:  (1)  representativeness of monitor-
ing sites and characterization of air quality  levels;  (2) compilation of  parti-
culate emission inventories for the  base year  and  projected  inventories for
future years*; (3) formulation of a model  to translate emission  levels into  sus-
pended particle concentrations.   The.  final  chapters  contain  a  procedure for
formulation and evaluation of an appropriate control  strategy,  including  the
consideration of emission control effectiveness, air quality impact, costs and
implementation problems.
 1.1   BASIC DEFINITIONS

 Fugitive Dust - A type  of particulate emission made airborne by forces of
 wind, man's activity, or both, such as unpaved roads,  construction sites,
 tilled land or windstorms.  A summary of  the  various  significant categories
 of fugitive dust  sources is listed in Table 1-1.  Two major categories are
 identified:  anthropogenic sources  (those which result directly from and
 during human activities) and wind erosion sources (those resulting from
 erosion of soil  by wind).  Fugitive  dust  is distinguished from  fugitive
 (industrial process) emissions  as defined  belpw;
 Fugitive Emissions - Particles which are generated by industrial or other
 activities and which escape to the atmosphere not through primary exhaust
 systems, but through openings such as windows, vents or doors, ill-fitting
 oven closures, or poorly maintained equipment.  Aggregate storage opera-
 tions and active tailing piles are included in this category of sources.
 *Refer to EPA's maintenance regulation in Subpart D, 40 CFR 51.
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                          TABLE  1-1.   FUGITIVE  DUST  SOURCES  CATEGORIES
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                          Anthropogenic  Fugitive  Dust  Sources
 V                        .   Unpaved  Roads
 g                        .   Agricultural Tilling
 I
 •                        .   Inactive  Tailing  Piles
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.   Construction  Activities
.   Street Dust
.   Off-Road Motor Vehicles
 9                         Wind  Erosion  Fugitive  Dust  Sources
 _                         .   Unpaved  Roads
 •                         .   Agricultural  Fields
   Disturbed Soil  Surfaces
                      1-3

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         and Baj,eJ ine - In assessing the impact of proposed emission
control  strategies, it is necessary to characterize the extent and
nature of the existing and anticipated conditions related to tiie air
pollution problem.   These "nominal" conditions are referred to as the
baseline.  Important baseline information concerns;  (1) baseline emis-
sions; (2) baseline air quality; (3) baseline control  policies; and,
(4) baseline meteorology.  For the purposes of this document, the base-
line consists of the baseyear, and projections for future years*.  The
baseyear is selected as the current or recent year, depending on the
availability of information to characterize the air pollution problem
suitably.
     In formulating control plans, it is necessary to distinguish between
control measures and control strategies.  A control measure refers to a
specific emission  reduction method applied to a certa-in source category.
A  control strategy consists of a collection of various control measures
to be implemented  jointly.

1.2  SUMMARY OF PROCEDURES FOR DEVELOPMENT OF CONTROL STRATEGIES  FOR
     FUGITIVE  DUST

Scope and Objectives
     The  development  of  an air pollution control  strategy  designed  to
attain and  maintain  the  National Ambient Air  Quality Standards  (NAAQS)
requires  an analysis  of  current  and  possible  future air  quality  problems.
 It is  the objective  of this  Section  to  briefly  present  the quantitative
and qualitative procedures  used  in developing  an  acceptable plan  for  the
 *Refer to  EPA's  maintenance  regulation  in  Subpart  D,  40  CFR 51.

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 I
            control  of fugitive dust.   The amount of work  involved  in  each  step  will
 |         vary from area-to-area depending on available  data,  magnitude of the par-
 ^         ticulate problem, types of emissions sources,  etc..  These  steps can  be
 ™         summarized as follows:
 •              Step 1.  Review air quality monitoring data to  characterize nature
                          and extent of suspended particulate problem.
 •                   a.  Assess representativeness of monitor sites.   Characterize
                          the general  area and tite site-specific area  around the
 |                       monitor.  Identify local factors which exert influence on
                          TSP measured at each site.  Establish  history of these
 W                       local influences and anticipated status in near future.
 m                       Evaluate if TSP levels at the various  sites  are represen-
                          tative of (1) the general area surrounding the monitor, or
 •                       (2) only the specific area near the monitor.  Assess the
                          implications of representativeness of station measurements
 ฃ                       for the utility of the particu'iate air quality data.  If
                          local sources contribute substantially to tne problem,
 B                       this may indicate that local sources need to be controlled,
 •                       whereas if analyses indicate areawide sources contribute
                          to the monitor, then areawide controls should be considered.
 •                   b.  Analyze patterns of the air quality data to characterize the
                          suspended particulate problem.  Various analytical procedures
 •                        may be employed to develop insights into the origin and
                          factors affecting the particulate problem.  The most signifi-
 •                        cant of these analyses concerns the apparent relationship

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        between meteorology and FSP levels.  Evaluate measured
        data to determine seasonal patterns of TSP and associated
        meteorology affecting the^e levels.  Analyze daily meteor!ogy
        and TSP data to determine apparent effect of meteorology on
        TSP.  Analyze meteoroloyiv dl  circumstances associated with
        particulate problem:  TSP trends  at various sites may be
        examined,  statistical correlations between TSP levels at
        various sites can be  developed, and the  geographic distribu-
        tion of TLiP  levels  may  i^veal  significant spatial patterns
        in the air quality  -.hu   ป,-  nonattainment problems.   Several
        ฐ>f these  potent^':  aialjsU methods are  described in
        reference  1.      i'<~ v a?  in,  ihls. analysis may  show  if
        local  or  specific  scan :es  contribute  substantially to the
         problem,  thus  indicating  the  type of  sources  that need  to
         be control!ea.
Step 2.  Develop  the baseline  particulate  emissions  inventory for
         sources  significantly jffecting the  problem area.
     a.  Identify particulate  sources  which may exert significant
         effect on the area experiencing the  nonattainment problem.
         Such sources may be  looted both within the urban areas
         and in the surrounding rural  areas several  miles from the
         urban centers.   Determine the geographic area to be
         included  In the analysis based on the relative significance
         and proximity of  ^ral  sources compared to other urban
         sources.
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                      b.  Select a uaseyear and estimate the emission levels for
|                        conventional sources including fuqitive emission and fugitive dust
—                        sources in tiiat year.  If seasonal levels vary distinctly,
•                        estimate emission levels by season as well.  Document the
flj                        emission inventory in terms of an emissions grid network.
                      c.  Project the baseyear emissions inventory to future years*
•                        by considering projected growth predictions related to the
                          various emission sources.  Predict probable emission levels
II                        and spatial distribution of these levels, and express in
                          terms of emissions grid network.
•                Step 3.  Formulate  an emissions/air quality relationship.
m                        Evaluate alternative source-receptor models and select an
                          appropriate relationship.  No single model is presently
I                        available  for application to all  areas where substantial
                          impact  of  the particulate emissions arises from larger
ฃ                        particles  originating from the fugitive  dust source types.
                          In lieu of a complete theoretical model  which is capable of
•                        accounting for deposition of particles,  there are  several
m                        approaches that  have been utilized in  previous studies
                          (Section 4).   It is  believed that these  techniques do have
I                          application in those arid western areas  with fugitive dust
                                                          2       "3
                          problems.   Continued use of AQDM  and  COM  appears to be most
 I                        reasonable approach  for those areas where  particles less than
                          10 micrometers predominate.
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                  Step 4.   Characterize  alternative  control measures for application
                           to  significant  fugitive dust  sources.   Identify control
                             Refer  to  EPA's maintenance regulations in Subpart D
                             40  CFR 51.
                                                    1-7

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         methods  available  for mitigation  of the  area's  most  signifi-
         cant dust sources.   Determine  probable effectiveness of
         these methods in the subject area.   Consult  with  local
         agencies to derive estimates of cost for the candidate
         control  measures.   Calculate expected cost effectiveness
         of the various measures, and compare results.
Step 5.  Select a control strategy and  evaluate the impact of the
         strategy on air quality.
     a.  Select a control measure for application to each  of  the
         major source categories and specific geographic areas
         which are the cause of high TSP levels in the nonattainment
         area.  The control measure selected should reflect the
         technical feasibility and reasonableness of the control,
         and will usually vary from region-to-region due to several
         general factors.  These factors should be considered before
         final selection of the optimum control measures.   Because
         of the many candidate controls for fugitive dust sources,
         selection of the overall control strategy may typically be
         an  iterative process accomplished by means of successive
         alternative trials.
     b.  Evaluate the  proposed strategy in terms of  its impact on
         emission levels and  TSP  levels, and  adjust  the strategy to
         meet the primary  air quality  standards.   Control effective-
         ness data  are  used  to estimate emission levels resulting
         from the strategy,  and  the air quality model is  employed
         to  estimate  resulting air quality.   To  obtain  this  objective,
                                1-8

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•                        degree of control,  geographic  area of control ,  type of

m                        control, and timetable of the  control  are manipulated

                          iteratively until  trie strategy achieves the primary standard.

ff                    c.   Estimate the cost of tiie proposed strategy, and assess

                          the problems associated with its implementation.  Political,

•                        legal  , and socioeconomic obstacles should be assessed,

                          and consideration should be given to alleviating problems

-•                        arising from strict regulatory approaches by adoption  of

.                        an alternative approach providing for integration of the

™                        dust control measures into ongoing governmental agency

flj                        programs.  A demonstration strategy can be considered  as

                          the first step in the development of the total  strategy

M                        which can reflect phased development.
I
                    SUMMARY
ฃ                       The remaining sections of the text provide detailed information
_                  regarding how to consider fugitive dust in the State Implementation
•                  Plans (SIP's).

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                 2.0   ANALYSIS  OF AIR MONITORING  DATA
                       In conducting preliminary analyses required for the technical base
                  of the control strategy formulation, existing air monitoring data must
fl|                be analyzed to characterize the nature and extent of the suspended par-
                  ticulate problem.  This characterization establishes the overall scope
•                of the problem and aids in identifying origins of the particulate prob-
                  lem.  This chapter outlines the procedures which may be employed to ana-
|                lyze  the air monitoring data  including monitoring site surveys,
—                statistical analysis of air quality data, identification of relationships
between TSP levels and meteorology, and relationships between TSP levels
and nearby sources.
 •                2.1   MONITOR  SITE  SURVEYS
 _                     Many decisions  concerning  air  program  planning  are dependent  upon
 ™                the  placement of the sensors  used to measure  air  quality.  Because ambient
 •                pollutant levels often  vary substantially throughout  a planning area, it
                   is evident that  contrasting siting  procedures can  result  in totally
 •                different air quality characterizations.  These differences have  important
                   implications  on  the  nature  of planning decisions for  air quality standards
 |                and  implementation programs.
                        Ultimately, a monitoring network cannot  possibly satisfy  all  siting
  •                criteria.  However,  the network can still be  very useful.  This utility
 m                can  be assured when  an  understanding of  the representativeness of  the
                   monitors, and the relative  levels of air quality  measured  there to other
 V               unmeasured areas in the study area, is  fully  developed.   One means of
                   developing this  understanding is the site  survey.
  I
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     In conducting the site surveys,  the geographic  range of representa-
tiveness of the monitor is estimated  by observation  of local  sources  and
topography surrounding the monitor.   Figures  2-1  through 2-3 illustrate
some potential  source orientations with respect to monitor stations.   In
Figure 2-1, the monitor is located in a rather homogeneous field of
sources, and the measurements should  be representative of the general
area.   In Figure 2-2, the monitor is  source oriented in an uneven field
of sources, and measurements there may only be representative of a very
limited space around the sensor.   In  Figure 2-3, the monitor is repre-
sentative of the shaded region of area source emissions.
      Figure 2-1. Monitor 1n
      Homogeneous Field of
      Point Sources.  Repre-
      sentation of General Area.
Figure 2-2.  Monitor in
Inhomogeneous Field of Point
Sources.  Site-Specific
Representativeness.
                          Figure  2-3.  Monitor  in  Field
                          of Area Sources  (shaded).   Site-
                          Specific Representativeness.
                              2-2
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                    A major i^sue  In  the  representativeness of  any monitor-  (such as that
  flj           in  the example above)  concerns  the  placement of  the sensor with respect
               to  sources  and topography  immediately  adjacent to  the  site.   If the sensor
  •           is  placed directly  in  an emissions  plume,  the measurements derived from
               the sensor  will  be  dominated  by this local  source.  If the source is well
  ฃ           described and can be quantitatively assessed, the  domination  of measure-
  .           ments may also be assessed and  the  readings recorded by the  monitor may
  *           serve as indicators for air quality nearby.  However,  it is  more desirable
B1

•
               that the sensor be placed  in  areas  where source  emissions  are  relatively
               mixed and spatial  variations  in  concentrations are  less  dramatic.   This  is
               particularly the case when the  local  influences  next  to  the  monitor are
               not easily described, and  their  accountability in the measurements  is  inde-
 ฃ            terminant.   A sensor located  next to  physical obstructions (i.e., too
 ^            close to ground, near a wall) can fail  to sense  the desired  pollutant
 ™            concentrations because ambient  air  streamlines are  directed  away from
 m            the site.
                    In summary, the air quality measured at a given  monitor may be repre-
 •            sentative of either a broad or  confined area.  In either case, if the  rela-
               tionship of air quality at the  sensor site to air quality at other  nearby
 |            points can be understood,  the monitor is representative in a useful way.
               If it is not possible to estimate or  assume this relationship  with  some
 •            certainty,  the measurements obtained  at the monitor are  of limited  utility.
 A            However, the data could be used  to  estimate the  degree of control needed for the
               impacting sources to achieve  National Ambient Air Quality Standards.   Site
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              surveys  can  provide  the  information necessary for these appraisals.
              Si te  Review  Procedure
                   Figure  2-4 illustrates a  proposed scheme for evaluating the  represen-
              tativeness of  air  quality measured by the existing monitoring network.  The

                                               2-3

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a             first step in  the  process  involves  a  compilation of  preliminary  data  prepara-
*             tory to  the site characterizations.   Frequently, significant  changes  in  the
•             surrounding environment  have  affected air  quality  levels  and  representative-
               ness of  air quality at  the monitor  site.   These  changes  should  be  documented
•             based on records of the  local  monitoring agency, and the  actual  site  visits
               later.
ฃ                  Each of the monitor sites should be visited,  and photographs  and plot
               layout diagrams should  be  performed to characterize  the  site  environment
™             and the  placement  and location of the monitor.
m                  Both the general area surrounding the site  (immediate vicinity in
               all directions) and the specific area at the site  should  be observed  and
f             characterized.  Potential  significant sources of particulate  emissions should
               be noted and described.   These sources include soil  dust  surfaces  subject to
m             suspension influences such as vacant lots, open  fields,  unpaved road  shoulders,
               residence yards,  unpaved roads and parking lots, excavated areas,  and agricul-
•             tural lands.  Observations of the general  area can be greatly aided by the
m             use of aerial  photographs if available.  Brief interviews with local  residents
               or employers may be conducted to establish changes which have occurred, or
I             are expected to occur,  in the monitor environment.  The historical changes
               should be documented so that it may be known what the measurements were repre-
•             senting at any given time of reference (i.e., the baseyear).
                    Based on the characterization of the  general  and specific areas  surround-
m             ing the monitor site, the representativeness of the monitor in expressing TSP
•             levels of the local area should be assessed.  For sites whose air quality is
™             typical  of that of the general area, the measurements there have direct
*•             utility  in representing ambient TSP exposure levels.
                    For other sites where the significance of factors affecting the repre-
•             sentativeness is uncertain, potential bias should be identified, and  awareness
               of  this  bias  should  be maintained throughout the  subsequent analysis  of the
I
I
source-receptor model  and  control  strategy formulation.
                                 2-5

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     No precise formula may be outlined for conducting site reviews.
Obviously, the procedures will vary greatly depending on budget, the
monitoring network, and the requirements of the control objectives.
The basic elements comprising the review are illustrated in the case
example (Figure 2-5) provided on the following page.  In this example,
the characterization of the general area and the specific environment
around the site were found to contrast.  Sources were prevalent adja-
cent to the site, which were not typical in the general environment.
Accordingly, TSP levels at the site environment were judged to be
representative in a site-specific manner only.
                               2-6

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1
f
I
1
 1
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 I
 I
 1
 I
  I
 1
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                         0_F__SITE_SP_t.CIF 1C  ENVIRONMENT

             The  plot  de.criotion  of  Figure  2-6  provides  an  orientation  for structures, objects,  and emission
        sources  in the iumpdiate  vicinity  of the hi-vol at  the  St. Johns site.  The  hi-Vols  is  located  or,  the
        rooftop  of the St.  Johns  Indian  School  administration building.  The  roof is  approximately  lb feet
        above ground level, and the sampler  is  mounted on a  conventional stand  1-1/2  feet  above the  flat  tarpaper
        rooftop    The  sanoler has  adequate vertical  clearance with all nearby objects  to the east,  north
        and northwest, but there  are  potentially significant vertical barriers  to wind movement from south
        of the hi-Vol, and rises  at its  peak to an elevation of 20 feet  about the hi-Vol sampler.   A small
        rooftop  room rises 8 feet above the  hi-Vol sampler  only 12 feet  to  the  southwest.  Air  movement from
        the west is obstructed by a school building which rises 8 feet above  the sampler.  A thick  hedqe  of
        trees rises 4 feet above the1 Hi-Vol  to the northeast.   These obstacles, in  addition  to  the  high elevation
        of the sampler above ground,  ire apt to prevent dust levels  experienced at  ground  level from being
        measured by the rooftop sampler.


              The  most significant  local source  of particulates consists  of fugitive dust.   The  suspenstoi  of
         this  dust  is  related  to vehicle activity and other activities which disturb the ground  surfa:e sifficiently
         to permit  suspension  of soil by wind.   Almost all activity in the immediate vicinity of the St. Johns  School
         occurs on soil surfaces.   Party measurements  may be considered
         negligible.  Then  is no  immec iate  plan which would affect significant  environmental changes to alter  this
         situation in  the   uture  (1980 and 1985).



Pinure  2-5.   Case Example  of  Monitor  Site Review:   St.  Johns Monitor  in  Phoenix  Area
                                                           2-7 -

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LEGEND:
          Designates Location and Orientation  for Photographs

          Soil  Surface

          Elevation44frป ^/.-ฐ^e  Ground  Level)
                •rm fi**
                                          •IfcMWf^***
          Plot Schematic of Environment in Immediate
            Vicinity of H1-Vo1  Monitor Site
            Figure "2-6   St. Johns Hi-Vol Monitor Site
I
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                              2-8

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2.2  Nature and Extent of the TSP Problem
     The air quality data should be analyzed to assess  the  nature  of  TSP
problem.  In assessing the origin of TSP levels and  the factors  affecting
these levels, it may be useful  to analyze the apparent  relationship between
meteorology and TSP.   The effect of meteorology on TSP  levels  will  provide
indications of the TSP origins, that is, whether the sources are predomi-
nantly anthropogenic fugitive dust, wind-blown dust, or conventional  sources.
The TSP/meteorology relationship may be demonstrated by: (1) evaluating
seasonal patterns of particulate levels and the associated  meteorology
affecting the levels;  (2) analyzing daily meteorology  and  air quality data
to isolate effects of single meteorology parameters  on  air  quality; arid
(3) investigating the meteorological circumstances  associated  with particu-
late episodes and other days of interest.
     Examples of procedures which may be used in demonstratina the TSP/
meteorology relationship are described in the Phoenix Study.       In  that
study, analysis of particulate episodes revealed clear patterns between
meteorology and high TSP levels.  Table 2-1 illustrates the two distinct
patterns occurring in the Phoenix area.  These patterns are typical of areas
where high levels of TSP are caused mainly by fugitive dust.   In the winter-
time, when low wind speeds and low mixing heights limit dispersion of parti-
culate emissions, high ambient concentrations generate consistently at the
city monitoring sites (Categories land 2).  Particulate levels also increase
at other stations throughout the entire region, but generally to a lesser
degree.  For the episodes associated with strong wind gusts, particulate
concentrations are highest in the rural and suburban residential areas
(Categories 3 and 4).  This  behavior is consistent with known facts regard-
ing the particulate sources:
                                  2-j

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TABLE 2-1.   PARTICULATE EPISODES IN PHOENIX AREA,  1973-1975.
STATHN
CATEGI RY
1
3
2
4
1
4
2
2
1
3
4
4
4
2
1
1
3
1
2
2
1
3
2
3
3
3
3
3
3
3
4
3
4
2
NA
*





DATE & STATIONS
November 12, 1973
Downtown Phoenix
Paradise Valley
West Phoenix
Chandler
November 18. 1973
Downtown Phoenix
North Phoenix
West Phoenix
Central Phoenix
January 17. 1974
Downtown Phoenix
Paradise Valley
West Phoenix
Chandler
June 16. 1974
Chandler
Mesa
Central Phoenix
Downtown Phoenix
November 13, 1971
Downtown Phoenix
Paradise Valley
South Phoenix
Central Phoenix
December 19. 197^
Arizona State
Downtown Pheonlx
Paradise Valley
Central Phoenix
March 25. 1975
Paradise Valley
LHchfield
St Johns
N Scotts/Paradise
June 17. 1975
N Scotts/P&radlse
St Johns
LUchfield
North Phoenix
August 10. 1975
St Johns
North Phoenix
Central Phoenix
Glendale
- no' available
St. tion Category: 1
2
3
4
5
6
AVERAGE RESULTANT
FIXING NO. OF DAYS WIND WIND DIR.
CONCENTRATION HEIGHT SINCE RAIN SPEED AND MAGNI- TEMP.
U0/m3 (Meters) , MPH) TUDE.
513 253 120 6.0 'M- 5.1 70
439
364
355
ซ8 394 ,26 98 jf. 3>9 63
389
337
480 108 9 43 -J_ 4j 58
351 trl
279
261
372 J888 75 10<9 -f- 6-1 98
322
239
454 352 n 3.7 \- 1.9 64
255 '
252
234
460 261 14 5.3 ^(- z.z 54
260
234
842 NA 11 12.2 -^- 4.6 66
379
346
295
1083 NA 69 11.4 ~T~ 4.8 88
798
519
248
456 NA 25 IX. 4 f O.J %
343
287
262

' Centr. 1 City/residential commercial surrounded by fugitive sojrces.
> Centr.l City/residential, no source In immediate surroundings.
• Rural, - residential , surrounded by fugitive sources.
Surbu'ban/residtntial , surrounded bv fugitive sources.
Rural, residential , no sources immed'ately nearby.
Remote
GENERAL
COMMENTS ON
WEATHER
haze most of
day. Maximum
wind speed 13
mph.
Partly cloudy
& thunderstorms
and wind gusts to
36mph beginning
at night.
Haze much of day.
Maximum wind speed
1 3 mph .
Clear, wind
gusts from SE at
43 mph.
Cloudy much of
day. Maximum
wind speed 13 mph.
Clear. Maximum
wind ipscd 12 mph.
Partly cloudy.
Wind gusts from
west at 35 mph.
Clear. Wind
gusts from West
at 35 mph.
Partly lluutly.
Wind gusts from
SE at 47 mph.







                              2-10

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•                      .  Human activity, which is most densely focused in the city
                           area, is responsible for sir pension of substantial fugi-
•                         tive dust emissions.  These emissions are of higher den-
ฃ                         sity than those released at the rural sites, and this is
                           reflected by the higher concentrations produced during
flj                         the stable atmospheric conditions of winter.
                         .  Because vast expanses of agricultural land, unpaved
•                         roads, and unimproved (but  disturbed) soil surfaces
                           surround the rural  sites, suspension of dust by soil
|                         wind erosion is very likely a dominant factor affecting
^                         high particulate levels during gusty winds in the rural
•
m                         areas.  Soil erosion by wind is of less consequence in
•                         the more developed  areas.
                     Various additional analyses of the data may be performed to char-
•              acterize the particulate problem.  Examination of TSP trends, statisti-
                cal  correlations between TSP levels, interpretations of pollution
8              roses,  and  inspection of geographic distributions of TSP levels are a
—              few  examples of the analyses which may  be performed.

                2.3   Air  Quality Data Analysis
"                   Two methods have been  suggested to determine to what extent a
•              given site  1s  responding to areawide emission patterns or one or two
                dominant  nearby  sources.  The first of  these  is  the pollution rose.
•              This is simply a graphical  presentation of the average concentration
                                                   4
                associated  with each wind direction.      Such a display requires only
g              daily resultant or 3-hour average wind  data along with TSP concentra-
                tions.  The calculation is relatively simple.  It is useful to
W              review the  pattern for each individual  site to determine if a particu-
                lar  or general wind direction is associated with high TSP  levels.
                                                 2-H
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Particular directions with higher concentrations may indicate a
particular source or small cluster of sources; higher concentrations
in a general wind direction may indicate an industrial area or a
weather pattern where rains and cleaner air are associated with one
wind direction and stagnant conditions with another.  Reviewing
several sites in the same urban area may indicate which is the case. '
     A second indication of local influence may be formed by comparing
the consistency by which concentrations are similar or dissimilar at
neighboring sites on the same day.  Various statistical analysis
(e.g., such as a multiple correlation analysis or use of a chi-square
test on the data among all sites for several years of data has been
used to indicate the level of correlation between neighboring sites).
Either calculation may be used to indicate which group of sites tend
to  have generally similar levels.  Similar levels between sites may
indicate that the sites are influenced by areawide  pollutant concentra-
tions or meteorological patterns and strongly dissimilar levels may
indicate an influence by  a nearby source that does  not strictly adhere
to  the general emission patterns of the urban area.
     The multiple correlation analysis may be extended to include
meteorological variables.  Data  such as wind  speed  or rainfall may
 indicate which sites are  affected by  wind-blown dust storms or fugitive
dust from  dry conditions.  A recent  study  used  average annual  values
of  rainfall  to  indicate  that changes  in annual  rainfall  did influence
TSP concentrations  •
     A multiple  regression  analysis  of 5-year data  sets  from 10 cities
 showed that a  l-1nch decrease  1n precipitation  is  associated with  an
                                        3
 increase  in annual  TSP levels  of 4  pg/m .   Such techniques  must be
 viewed with caution because  the relationship  may not be  precisely
                                 2-12

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I
•             linear as implied by the regression.  Non-linear transformations
               of the data are recommended where appropriate.
|                 The effect of  long-range transport on TSP levels may be  indi-
               cated by the calculation of the path of the air parcel as it  moves
™             across the U.S..  Such calculations  have been made by computer aided
•             analysis using a model  developed by NOAA, Air Resources  Laboratory.
               Such analysis may be used  to indicate the general geographical  sources
•             of exceptionally high TSP  or sulfate levels.
                   Several other  methods have been used to provide gross  estimates
               TSP  problem  assessment  study.      This study indicates that there is
•             of the  sources  of TSP.   One  such method  is  summarized  in  a  National
1
I
               a  relatively  constant  average  contribution  from  general  urban  activity
               from city-to-city.   Using  this empirical  value,  known  values of  non-
               urban background  and secondary TSP,  it  is possible  to  determine
•             iteratively which sites  have major  influence  from local  sources  and
               the approximate level  of impact of  industrial  particulates  on  TSP
•             levels.   Another  method  to indicate,  in a very general way, the  rela-
               tive contributions due to  traffic and industry is to calculate changes
fj             in weekend and weekday concentrations.   To  do this, the  daily  varia-
—             tions in  both industrial  emissions  and  average daily traffic should
™             be known.
•                  Another  aspect of data analysis  is the examination  of  the hi-vol
               filter to determine the  components  of the aerosol on the filter.  The
•             most straight-forward approach is polarized light microscopy.  This
               technique can yield a semi-quantitative assessment  of  the generic  type
H             of particulate.   Such an examination  should be undertaken only in  con-
               junction  with a quality  control program to  ensure the  consistency  and
^H
I
               replicability of the results-
                                               2-13

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     More sophisticated techniques for the identification of individual
particles are available, but resource limitations usually preclude
their widespread application.  Such techniques include scanning electron
microscopy, Ramon spectroscopy, Electron Scanning for Chemical  Analysis
(ESCA) and electron microprobe.

SUMMARY
     In general, the site reviews and data analysis performed in the
preceding Sections provide a useful tool for assessing whether local
or specific sources contribute substantially to the problem, thus
Indicating the type of sources that need to be controlled.  Also, this
qualitative assessment can be employed to indicate areas where the
results of modeling analysis (discussed in Section 4.0) should be used
with reservations as to their representativeness.
                             2-14

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I
fl                        3.0 EMISSION  INVENTORIES AND PROJECTIONS
                   The  development of air pollution co-.trol strategies depends on a
•             detailed  knowledge  of  the quantity  and character of pollutant emissions
m             in  the  region.  Appreciable concern has been devoted  to the  character-
™             ization of conventional sources,  and various data sources  (i.e. NEDS)
•             are available  for the  rapid assembling of  regional and area-specific
               emissions. With  the realization  that fugitive dust emissions also exert
I             a substantial  impact on air quality nonattainment problems,  efforts
               are now being  increased to develop  detailed characterizations of the
g             various fugitive  dust  sources.  Such efforts have recently been employed
                                                                                  q
               to  develop a fugitive  dust emissions Inventory for the Phoenix area,
B             The procedures  employed during  the  Phoenix Study are  generally applicable
•             for characterizing  fugitive dust  emission  in other regions as well, and
               are summarized  herein.  This  chapter provides an outline of  recommended
I             procedures, including  numerous  examples of applications as applied to
               the Phoenix Study.  Section 3.1 concerns the estimation of emissions for anthro-
•             pogenic fugitive  dust  sources and Section  3,2 Involves estimation of fugitive
               dust emissions  resulting  from wind  erosion.  Section  3.3 describes the general
m             considerations  associated with  forecasts for emission levels in future years.
ซt                 The  procedures for compilation of conventional sources  emissions are
               not repeated here.  They  have been  in use  for some time and  are documented
•             in  the  literature.  '         The  emission  factors given herein are com-
               patible with AP-42, "Compilation  of Air Pollutant Emission Factors" or
]|             will be reflected in future updates to AP-42.  As improvements in these
               factors are made, they will also  be reflected in AP-42; therefore, the
•             user should assure  that the latest  information is used.

I

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     For potential  utility in  air quality impact analysis,  estimates  of
both fugitive and conventional  emissions  should be organized and spatially
disaggregated for description  in a point  source and grid network of the
study area.  Each emissions category should be adequately described and
reflected in the grid network.   Area source emissions  should be tabulated
for each of the grid squares for modeling purposes.  The grid boundaries
are defined by considering all  sources which might significantly affect
air quality in the target control area as well as any model constraints
that exist.  For areas characterized by numerous fugitive dust sources,
relatively small grid squares, but not less than a kilometer on a side,
should be considered to permit analysis of the Impact of these sources
on a local scale.  When practical, emission sources should be spatially
resolved to a greater level of discrimination immediately around the
monitor sites.  The gridding procedures have been in use for some tine
and are well documented in the literature.1      One of the modeling
approaches discussed in Section 4 uses particle size ranges for describe
ing the air quality/emissions level relationship.  This d1saggregation
by particle size range 1s based on particle size information contained
within this section.
     Emission inventory grid systems may be developed after, or before,
the emissions are  calculated.  For Inventories  involving extensive
evaluation of small scale or localized problems where it is critical
that emissions  be  located fairly precisely, it  1s  usually  necessary to
use preliminary Inventory  results and knowledge to develop the  grid
system 1n  advance  of  locating and quantifying all  the sources.   If the
alternate  approach of developing the grid system after calculations are
complete  is used,  then many area source  emissions will have to  be re-ap-
portioned  from  aggregate totals  to various grids by approximate
                                   3-2

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 I
 ฃ           and locally customized apportioning factors.  The former procedure is
             usually preferable for fugitive dust considerations.
 I
             3.1   ESTIMATION OF BASEVEAR ANTHROPOGENIC FUGITIVE DUST EMISSIONS
 ™                For the context of this document, anthropogenic fugitive dust
 •           sources are considered to be those resulting directly from, and during,
             human-related activities.  These include motor vehicles on unpaved
 •           and paved roads, off-road motor vehicle activity, construction activities,
             etc..  Section 3.1.1 through 3.1.7 outline general procedures for estimating
 ฃ           emissions levels from several of these sources.

 I
 •           3.1.1   Motor Vehicles on Unpaved Roads
 —                  The basis for estimating fugitive dust emissions (j^ 20%)
 I
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arising from motor vehicles traveling on unpdved roads as derived
from AP-42 is:
                           \ /365-W
I
                            e =
•           where          e = emission rate (Ib/vehicle-mile)
m                          s = silt content of road surface (percentage by weight
                                of particles smaller than 75 micron diameter)
1|                          S = average vehicle speed (mph) (valid between 30-50 mph)
                            W = number of days with 0.01 in. or more rainfall
     It is reasonable to adjust the above by a multiplier factor of I j
                                                                    * ^ i
applied to vehicles with more than four wheels where N = number of wheels
                                              3-3

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on vehicle.  Also, if local  conditions in the area and time period
under consideration warrant, "W" -hould be modified by a multiplier
equal to the average number of days required for the road surface to
return to the dry state.
     Dust emissions from unpaved roads generally exhibit the following
particle size distribution (from AP-42):
              PARTICULATE DIAMETER             WEIGHT PERCENT*
                     < 30 p                          60
                     > 30 v                          40
     The data base required for estimation of dust emissions from
unpaved roads in a given study area will Include:  1} mileages and
distribution of unpaved roads, 2) vehicle speed, 3) average dally
traffic, 4) silt content of road surfaces, 5) number of days of
rainfall >0.01 inches, 6) average number of days required for road
surfaces to return to the dry state and if significant, the average
number of  wheels per vehicle.
     The spatial resolution of unpaved  road mileages should be accom-
plished in cooperation with the local transportation department.  In
one applicable approach, a grid is Imposed on a department road map
 *Note:  One of the modeling approaches discussed in Section  4  uses  particle
 size ranges for describing the air quality/emissions level relationship.

                                    3-4

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showing the various road classes (dirt, gravel,  paved).   The mileages
of each road class are scaled and recorded for each of the grid squares
of the network.   In another alternative approach, road mileages and
classifications  are related to road maintenance activities in fixed
maintenance districts.  Computer based summaries of the maintenance
activities in each district may be available and will  facilitate the
determination of road surface type and mileage in each such district.
If a single transportation department is not responsible for all roads
within a study area, it will be necessary to consult other appropriate
local departments (e.g., county, the major cities, unincorporated cities,
private organizations).
     Average vehicle speed and average daily traffic (ADT) on unpaved
roads are frequently difficult to determine since there is generally
little incentive to study traffic behavior on roads carrying limited
traffic.  Speed and ADT estimates then must often be based on rough
approximations from interviews with local transportation department
personnel and/or by limited traffic studies conducted for representa-
tive road types.  Expected vehicle speeds for unpaved roads in areas
                                       i ?
studied have been between 30 to 40 mph,      but local data should be
used if available.  The equation above has been developed using speeds
between 30 and 50 mph.  Speeds in excess of 50 mph are not likely.  If
speeds below 30 mph are encountered, however, caution and engineering
judgement should be employed 1n extrapolations.  ADT is typically less
than 100 vehicles per day on most unpaved roads.  Table 3-1 shows some
typical values of ADT for various unpaved road types in the Phoenix
Area.  Always use locally developed data if available and reliable.
                                   3-5

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         TABLE 3-1.   AVERAGE DAILY TRAFFIC VOLUMES  ON  UNPAVED
                             ROADS IN THE PHOENIX AREA
     TYPE OF ROAD                         AVERAGE DAILY  VEHICLE COUNT
                                             URBAN            RURAL
County:  dirt   - county maintenance           75               40
                - no county maintenance        15               10
         gravel - county maintenance          100               60
City   :  dirt                                  75               40
         gravel                               100               60
     The results of a field sampling test9 in  Phoenix  indicate
that the silt content of soils on unpaved road surfaces reaches an
equilibrium value substantially less than that of the native soil.
Fines are readily removed from the road surface by vehicle traffic,
and equilibrium of the particle sizes is attained with a higher percent-
age of coarse particles than are observed in the native soil.  Based
on the modest tests performed by TRW, any relationships formulated
between native soil characteristics and road surface particle distri-
butions are highly questionable.  Until indices of road silt levels
are available, site-specific field data is needed to insure suitable
 parameterization  of  theAP-42 emission estimate eouation.*
     The spatial  variation of road surface silt levels throughout a
study region should be documented by relating general soil maps to
the field test results.  Accordingly, road surface sampling sites
should be selected 1n areas that are representative of the major
 unpaved road surface types, as  determined by  preliminary assessment
 of  the soils maps.
*Note:  AP-42 is  being revised  to include this.
                                    3-6

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     Rainfall  effectively reduces emissions of road dust to near zero
during the period the surface is wet.   The drying effects of traffic,
wind, low humidity, and solar radiation will  usually return the surface
to its equilibrium state in one to three days, depending upon the extent
of the rainfall.  One day may be assumed as a default average, but local
experience should be utilized for the  particular soil, season and other
conditions experienced during the period of interest for the area
involved.  The "W" factor in the equation should be adjusted to reflect
this local experience (i.e., "2W" for two days drying time).
     The emission  rates may be affected by large numbers of heavy
vehicles having more than four wheels.  While there is speculation
that vehicle weight is the governing factor, larger and heavier vehicles
have more wheels to carry and distribute their loads.  Therefore, if
the proportion of such heavy vehicles  is significant, it may be necessary
to utilize the  "N" factor multiplier for the emissions equation.
     Once the various influence parameters have been quantified within
the grid network, dust emissions for unpaved roads are calculated using
                                            \
 the  equation.   For example,  a one-mile length of unpaved roadway with
surface silt content of 20%, carrying 100 light duty vehicles per day
at an average speed of 35 mph, will emit:
               e *J0.81(20)(35/30)(100)(1)= 189 pounds
                   of suspendable dust per day (assuming no rainfall and
                   all four-wheeled vehicles.).
 In developing the complete unpaved road emissions inventory, the cal-
culation is performed for each of the various road links within the
                                   3-7

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grid network.   In the limit,  when  the data  base  is  complete,  this  process
involves a separate calculation  for each  identifiable  link.   Generally,
the available data base for unpaved roads provides  less discrimination,
permitting the aggregation of road links  of a given "average" description.
It may be useful  and efficient to  computerize the emissions modeling  effort,
both for actual calculations  as  well as for display of results.  This deci-
sion will be dependent upon local  capabilities and  resources.

3.1.2  Entrapment of Street Dust
       Vehicles traveling on paved roads and streets are  likely to be a
major source of fugitive dust emissions.   Based on  two separate studies  of
                        13-14
re-entrained street dust     , an  average dust emission rate  of .012  lb/
vehicle mile has been established  [as shown in Table 3-2 soon to  be  pub-
lished In AP-42, Supplement 8].
                             Table 3-2
     Measured Emission Factors for Dust Entrapment from Paved Roadways
      Study
               Emission  Factors
              (Range and Average)
       Reference 13
       Reference 14
       Average  (overall)
                           q/veh1cle-km
                             Ib/vehicle-mile
                           Range
             Average
2.8-5.6        4.3
0.26-10.4      2.6
          3.5
    Range        Average
   0.01-0.02      0.015
0.0009-0.037      0.0009
            0.012
                                    3-8

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m
•
I
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I
                   The  utility  of  the above emission factor depends essentially on  the
              ability  to  quantify  the vehicle miles traveled  (VMT) on paved  roads or
              streets  during  the base year or of other years  of  interest.  The informa-
              tion  necessariy for  this characterization  can  usually  be  obtained  from
              internal  documentation available within various State and  local agencies.
                   Dust emissions  from paved roads  generally  exhibit the following
                                         14
              particle size distribution.

                                Particle  Size                 Weight Percent
                           Greater than  30 ym                     10
                           Less  than 30  urn                        90
                           Less  than 5 urn                         50
•            3.1.3  Construction Activities
                     Construction activities  inevitably result  in  the  exposure  and  disturb
•            ance of soil.   Fugitive  dust  is emitted both  during  the  activities  (i.e.,
              excavation, vehicle  traffic,  human activity),  and as  a  result  of wind ero-
•
              si on over the exposed earth surfaces.  The major construction of interest is
              typically occurring in "heavy" construction activities,  such as roadway con-
              struction and residential/commercial/industrial  building which involves dis-
              turbance of significant quantities of soil surface area.
                                                    3-9

-------
     Based on field tests  conducted  at  construction  sites,    an
average dust emission rate of 1.2  tons/acre/month for active construc-
tion has been established.  The  test results  do  not  include  an  analysis
of the expected particle size distribution  of emissions.   Until  further
study results are available to characterize construction  emissions,
the particle size distribution may be assumed to approximate that of
the lower ranges (less than about  100 microns) of the parent soil.
Parent soil distributions  may be obtained from published  USDA soil  surveys.
     The utility of the above emission factor depends essentially on
the ability to quantify the acreage  of soil which is disturbed during
the various construction projects  occurring in the baseyear  or of
other years of interest.  The information necessary for this character-
ization must usually be obtained from.internal documentation available
within various local agencies.
Roadway Construction
     Roadway construction activities and associated mileages may be
obtained and characterized by consultation with state, county, and
city transportation departments.  Table 3-3 illustrates the tabulation
                                                   g
of  this type of data obtained for the Phoenix area.      The data
are approximate, but based on the uncertainty associated with univer-
sal application of the average emission factor,  more precise survey
efforts are  unwarranted.  Based on  average roadway clearing widths
used  in construction, the average area of  exposed surface may be cal-
culated.   Significant borrow pits outside  the roadway may be important
in  areas  requiring  extensive cut  and fill  such  as will exist in  hilly
or  mountainous  terrain.   The duration  of active  construction, during

                                   3-10

-------
I

'           which the road bed is exposed soil, is  typically about 6  months  for
•           a major road job of one mile length and 80 feet width, and about
             2 months for each half a mile of local  streets 33 feet wide.
•           Various widths of right of way disturbance may also be involved and
             should be considered.  Local regulations and practice are giving more
|           and more attention to reducing this exposure time by temporary  seeding
^           or other stabilization, and should be considered in this  analysis.
™           Based on an average emission rate of 1.2 tons/acre/month, the dust
•           emissions arising from road construction are calculated by multiply-
             ing the average emission rate of 1.2 tons/acre/month by two terms:
•           1) acres of soil exposed in road construction, and 2} the average
 —
 •
 m

 •


 •
I
I
             duration of the soil disturbance.  Because of the variable location
             and relatively minor effect of roadway construction emissions, efforts
             to resolve these sources spatially on the grid network should usually
             be limited.  It is normally adequate, for example, to allocate con-
             struction dust emissions equally to all grids on the emissions grid
             network that are within the entire city boundaries, and to allocate
             road construction dust for the county and State Highway Department
             equally to the grids in the county portion of the study area network.
             Resi denti al /Commerci al / Indus tri al Construct! on

                  The most significant source of construction dust typically arises
             during the building of residential/commercial/industrial structures.
             Residential housing usually comprises the major portion of the activity
             in this construction category.  Housing construction can generally be
                                               3-11

-------
        TABLE  3-3.  SUMMARY OF  ROAD  CONSTRUCTION
                     ACTIVITY  IN PHOENIX AREA, 1975
RES'C'iS.'dLE
AGENCY
County
Phoenix
Glendale
Paradise Valley
Peorla
Mesa
Tempe
State Highway Dept
IMPROVEMENTS SUBDIVISION
(MAJOR & LOCAL (PRIVATE CpN-
ROAOS) STRUCTION*
20.0
26.4
0
1.5
0
' 0
0
0
47. 9C
*' Of those roads financed
highways 80' wide, and
Averaca width
Average width
of these
of local
MILES OF ROADWAY
56.0
58.7
14.7
2.8
0
32.7
10.3
0
175. 2b>
by federal aid. 18.9
37.3 miles are 2 land
roads Is 33 feet.
and major roadways 1s
FEDERAL
AID
SYSTEM
15.8
3.6
0
0
0
0
0
36.8
56.2*
miles are
highways

55 feet.
CITY !
OR
COUNTY TOTALS
128.7
1.4
0
.6
i
2.1
0
0
0
1 132. 8b'
4 lane
48 ft. wide.


     MoplUy
  Total Houttng VMM

  'CD
     300-999
Dntriet
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
*Sป
\m
TซMl
1974
fl^M^M
Uwปf>
Singte
319
933
548
332
127
744
32
37
7
9
6
39
734
16
211
513
1,184
808
1,846

8,705

11,280

-22.8%
TownhouM
43
5
—
8
7
—
_
12 ..
—
—
—
—
—
—
—
104
v 32
22
176

409

2,354

-82.6%
AWN**
13
9
17
440 "
—
10
152-'
20
15
95
2
_
-_
21
— •
14
- 3'."
30ป
2
i
t45."
, ,
6,073

-86.)%
YoMJUW*
373
,.947
5*5
.1,000.
. 134
734
.. 5(04' .
69
22
104
9
3P--
' 734
37
24)
. 631
tjJQI '
880
,/a^"*,'
* *
9,959

1ป,J07
t-
-49.5%
Sourct- M*rlcซM County Homing Study Commmw, M. R. WN) MiMttkw
        ti, inc.
                                                          Ib
FIGURE 3-2.   NEW HOUSING UNITS  IN  MARICOPA COUNTY, 1975
              (Based on Building  Permits issued January
               through December,  1975)
                              3-12

-------
 I
 I
             characterized from data available from local building and safety depart-
•           ments, but often this data is assembled it. summary form and published
             by various local service organizations.  Figure 3-2 illustrates a
flj           typical format for presentation of building permit data to describe
             new housing unit starts.  Average unit land utilization for various
I           housing classes may be determined from sources such as local planning
             departments, building and safety departments, and local service organ-
 I
 I
I
I
              izations.  This determination may involve a synthesis of several input
                        Q
              data  items,,;     such as land use ratios, average occupancy rates by
              dwelling  and housing unit inventories and should consider the portion
 •            of the land area disturbed by typical construction practices utilized
              locally.  Average land utilization rates are then combined with new
 M            housing start data to calculate disturbed soil area associated with
              housing construction in the various districts.
                   Disturbed soil acreage occurring from land use development other
 •            than housing may be determined by employing calculation procedures
              similar.to that described above for housing construction.  If data
 •            are not readily available to characterize commercial, industrial, and
              public construction projects, historical land use ratios between the
 •            various land use types may be applied to construction acreage totals
 M            for these land use categories.  Estimates of dust emissions arising from
 *            all categories of construction activities are then generated by apply-
 •            ing the general emission factor of 1.2 tons/acre/month to the number
              of acres disturbed by construction in each definable district or
 •            sector.  The building construction emission levels are then assigned
                                                3-13

-------
to the emission grid network by any suitable  allocation  procedure
(i.e., a grid network overlay may  be used to  accomplish  the  appropriate
allocations).
3.1.4  Agricultural Tilling Operations
     Based on field measurements      of suspended particulates  arising
from tilling operations, the equation as given in AP-42 for
estimating tilling emissions 1s given as:
               a -  T-4s
               e = 	*•
where          e = emission rate (Ib/acre),
               s = silt content of soil surface (percent), and
              PE = fhornthwaite's precipitatton - evaporation index
                  with implement speed being typical (5-7 mph).
     Two general assumptions apply to the estimation equation
involves the type of implement.  The field tests reflect utilization
of one-way disk and sweep-type plows.  In practice, a wide variety of
implements are employed, ranging from disk plows to moldboard plows to
listers.  It is assumed that emissions do not differ greatly from one
implement type to another.  It is also presumed that no irrigation
is conducted before plowing.  In areas where irrigation is employed,
fields may be flooded with water to leach out salts from the previous
season, but this occurs after plowing.
                                  3-14

-------
     Test results indicate that,  on the average,  dust emissions from
agricultural  tilling have the following particle  size distribution
but may vary  according to the local soil  characteristics.
               Particle Diameter           Weight  Percent
                     < 2M                       35
                     2-30 u                      45
                     > 30 y                      20
     The data base required for estimation of dust emissions from
tilling of agricultural fields Includes:   1)  silt content of the soil,
2) implement speed, 3) distribution of agricultural acreage, 4) tem-
poral distribution of tilling activities, and 5)  the Thornthwaite
preci p1tati on-evaporati on i ndex.
Soi1 Si 11 Content
     U.S. Department of Agriculture Soil  Sample Analyses are published
and made available for use in potential farmland areas throughout the
country.  These analyses typically include a detailed particle  size
distribution for case samples from various representative sites in
a given area.  The data may be used to estimate the silt content as
defined by the emissions equation  (the percent by weight of the. top four
inches of soil having particle diameter from 2 to 50 microns).  The
soil silt measurements may be related to soil types identified on
general soil  maps, and agricultural regions may then be located on the
soil maps with the use of aerial  photographs or some other suitable
procedure.  An average silt level  is estimated for cropland within
                                   3-15

-------
each grid square (or some other suitable geographic jurisdiction such
as a township) by weighting cropland acreage with corresponding soil
silt levels.
Distribution of Croplands
     The spatial distribution of croplands may be determined from aerial
photographs of the study area.   Potential cropland, which was fallow at
the time the photo was taken, may also be identified, and confirmed, with
photos corresponding to another growing period.  By scaling of the photos
and the suitable use of grid overlays, crop acreage in each of the grid
squares may b^ quickly estimated.  Frequently, such estimates are already
available (by some alternate grid system) in documents published by state
or local agricultural agencies.  A check should be made to compare the
total compiled agricultural acreage-with alternative sources of published
cropland totals.  When patterns of crop types are available, acreage in
each grid square by crop type may be documented.
Implement Speed
     Limited data are available to  characterize typical speeds of tillage
          17                                             9
implements        Investigation during the Phoenix Study     confirmed
previous findings that a speed of 5-1/2 mph  is generally representative
                          r18
of most tillage operations'   .
     Since  agricultural  tillage occurs  seasonally  based on crop type,
the  resulting  emissions  from this activity  should  be expressed  by
season.  To permit  discrimination of  emission  by season, it  is  neces-
sary to characterize  1)  the  tillage period  for each crop type,  and
                                     3-16

-------
 I

 ™           2) the acreage of each crop type.  Moreover, if this seasonal discrim-
 •           ination is to be made on a grid basis, the spatial distribution of the
              different crop types must be determined.  The latter determination is
 •           often non-productive in areas where use of agricultural lands is
              unpredictable, or is constantly changing.  In these cases, a constant
 jf           distribution of crop type may be assigned throughout the study area.
 m           However, if specific geographic patterns for cropland use can be iden-
 •           tified, these data may be used to establish a varying spatial distri-
 •           bution for agricultural acreage by crop type.
                  The tillage periods for various crop types depends on regional
 Q           considerations and may be identified by consulting with local agri-
              cultural agencies.  Figure 3-3 illustrates the planting period for
 •           major crops in the Phoenix area, obtained from local publications
                                                                 1R
 •            of the Arizona Crop and Livestock Reporting Service.       Tillage
              is assumed to be distributed over the planting period.
I
I
I
Thornthwaite Precipitation-Evaporation Index
     The Thornthwaite Precipitation - evaporation index is used to
              reflect moisture exchange between soil and atmosphere.  The use of this
B            expression  is an attempt to quantify the suppression or encouragement
              of  emissions by the presence of moisture in the soil.  The  use
•            of  index  for a specific area and baseyear is discussed in Section 3.2.1,
              Calculation of  Emissions
I
                   Once  the  various model parameters have been characterized for the
•            grid  network,  dust  emissions  from tillage operations are calculated
                                   3-17

-------
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3-18

-------
I
             using the emission equation.   For  example,  consider a  grid square  in
m           which TOO acres  of cotton were grown  in  the baseyear.   If the silt
m           content of the soil was 50%,  the tilling implement was run at a
             typical speed of 5-1/2 mph, the PE index was 50, and the tilling  season
I           was from March through April , the  dust emissions resulting from  the
             tilling are:
I                         e = -'4 (50) =  70 Ibs/acre
•
-
™
I
             or the total daily emissions from the grid square during the tilling
             period is:
                  Emission estimates should be located and described on the emission
             grid.
             3.1.5  Off -Road Motor Vehicles
                  Recreational vehicles traveling off-road on native soil surfaces
•           may generate significant dust emissions in some locales, particularly
             during weekend periods.  While the impact of non-construction off -road
•           vehicle emissions is minimal in most metropolitan areas, air quality
             near the areas of greatest activity may be sufficiently affected to
•           require consideration.
.                Because documentation of off -road vehicle activities is very
"           limited, only crude emission approximations are possible at this
•           time.  Based on the emission factor for motor vehicles on unpaved
             roads (Section 3.1.1), the rate of dust emissions arising from off -road
•           vehicle activity would be:
                               e=.81s()()
™
•
             where             N = 2 for motor bikes and 4 for 4-wheeled vehicles
                                               3-19

-------
     The size distribution of particles  emitted from off-road  vehicle
activity is assumed to be the same as  that emitted by motor vehicle?
on unpaved roads.
     The location, operational characteristics  and activity levels
for off-road vehicle recreation may typically be best determined by
consultation with local motorcycle associations, city parks and recre-
ation departments, the Fortst Service, the Bureau oi Land Management,
etc.  Based on discussions with cognizant organ-JzitlohS in the Phoenix
      20,  21,  22,  23,  24,  25     ' , . ,   x  UJ1
areaj                       a typical motorbike  rldar was
assumed to travel about 45 miles per outing at an average rate of
15 miles  per  hour.  The average trip length for  a, four-wheel  vehicle
was assume*1 tw be 150 miles at an average speed  of 30 miles par hour.
Vehicle activity  levels are generally several tlines greater for
end days  as compared  to weekdays.
      Silt content of  areas used for off-road  travel mi\y be
by combining  information  from general soils maps and the results of
soils surveys available from the local branch of tte* U.S. Departซ)ent
of Agriculture Soil Conservation Service.
      In documenting emissions estimates, a distinction should  he roads
between weekend-day levels and weekday /levels.   The weighted dally
                                     /
average should be computed for consideration  in  air quality modeling
of annual TSP averagtt  (SactfcM 4).
 3.1.jSTunprnd  Park** Lots  *d Truck Sttft
      The  dust emission rate  for  vehlcles^'travtnng fh~ unpaved parking,
 lots  or truck stops  1s assumed to  be  the  same as that  for vehicles  on
                                                                     /*
 unoaved roads.   Based on  an  exponential increase 1n the  emission  rate
 for  vehicle speed from 0  to  30 miles  per  hour, the emission fac-
 tor  for a typical parking lot surface of  24%  silt  level  would  be  2.2
 pounds/vehicle  (4-wheel)  mile at an average  vehicle spead  of  10 miles per
                                   3-2n

-------
 I
 _          hour.  For a gravel surface, the silt level is about 12%, and the parking
 •          lot dust emission rate is about 1.1 pounds/vehicle mile at a speed of 10
I             miles per hour.
                                                 •' ti
                  Total parking lot dust emissionsปare estimated by (1) determining
 I          the average number of vehicles using the lot each day and the average
             distance traveled by each of the vehicles, and (2) by calculating total
             •vehicle miles traveled daily and multiplying this rate by the ^em'tesion
                                                                           t'   %J
             factors discussed above.  In an alternative approach, average vehicle
 I          miles traveled may be related to parking lot size.  For example, in one
 *                                                                                    4
 IB          recent study to characterize factors influencing fugitive dust emissions!,
                  , it has been assumed there are 190 VMT/year per 10,000 square feet
 B          of  parking lot.  Based on this assumption, unpaved parking lot emission
             rates may be summarized as follows:                          •,
 •               e = .21 (N/4) ton/yr. per 10,000 sq. ft. for parking lots with
                      surface silt content of 24%.
 I                e = .10 (N/4) ton/yr. per 10,000 sq. ft. for parking lots with
 m                    surface silt content of 12% (gravel surface).
 *                Where N = average number of wheels for vehicles traveling in parking
 •                          lot.
                  The particle size distribution of the parking lot emissions is assumed
 •           to  be equivalent to that emitted off unpaved roads (see Section 3.1.1).
 ซ           3.1.7  Aggregate Storage Piles
                  Based on field measurements^     of suspended dust arising from
•           aggregate storage operations, average emission factors for three categories
             of  process activity (active, inactive, and normal mix) are as shown in Table 3-4.
•           Sources of the aggregate process include loading and unloading to the storage
             piles, traffic movement among the  storage piles, and wind erosion.  The  factors
|           shown are representative for storage piles in areas with climatic conditions
I             similar to Cincinnati; however, the values may be adjusted by applying the
                                               3-21

-------
         TABLE  3-4    EMISSION  FACTORS FOR AGGREGATE STORAGE PILES 17
                         Aggregate Storage Operation
      Pile  Status

    Daily Activity3
    Inactive
      (wind-blown  emissions  only)
    Normal  activity mix b'c
      Composition:
        Loading onto piles
        Vehicular  traffic
        Wind  erosion
        Loadout from piles

         a8-12 hour activity/24  hour  day
           *C5 active days/week
               Emissions:
       Lbs/acre/day -or-  Lbs/ton placed
       	        in storage
           13.2               0.42
            3.5               0.11

           10.4               0.33

                              0.04
                              0.13
                              0.11
                              0.05
                      total   0.33
      A correction factor of
effect of regional climate.
2,should be applied to account for
                                     3-22

-------
                     PE   2
correction factor V(YQQ-)   to  the  total  storage  process  emission factor,  where
PE is the area-specific  Thornwaite Precipitation-Evaporation Index.
                                         17
     Field tests that have  been conducted   have revealed  the particle
size distribution for one of the representative  operations (aggregate
loadout) to be as follows:
                Particle Size            Weight Percent
                    <1  y                      30
                   1-2 y                      46
                   2-3 y                      16
                   3-4 y                       6
                    >4 y                       4
     Estimation of total dust emissions resulting from aggregate  storage
operations should be conducted using an appropriate emission rate selected
from Table 3-4.  Activity of the storage operation is generally documented
through the permit system of the local  air pollution control agencies.
Dust emissions are then calculated by combining the appropriate data and
emission rate selected from Table 3-4.   For example, consider an aggregate
operation with a storage of 10 acres and a normal mix activity, located in
an area with a PE Index of 50.  The rate of dust emissions arising from this
enterprise would be:
                          104
                      e = •L^-L =41.6 Ibs/day/acre of storage
or 416 Ibs/day total emissions from the entire aggregate storage operation.
3.2  ESTIMATION OF BASEYEAR WIND EROSION EMISSIONS
     This section includes procedures which may be used to estimate fugitive
dust emissions resulting from wind erosion of soil.  Section 3.2.1 describes
the general emissions model and the data base required for calculation of
wind erosion emissions.  Section 3.2.2 outlines specific considerations
involved when applying the emissions equation to various source categories.

                                  3-23

-------
3.2.1  General  Methodology
     The exact mechanisms causing entrainment of the soils  are not
yet fully understood.  The quantification ur these mechanisms for
application in air pollution studies will not be availab"!a  in the short
term.  Presently it appears the most plausible approach for estimation
of wind-blown dust, is to assign a suspension rate to the horizontal
                                                                    28
soil movement as determined by the established wind erosion equation
       This approach has been used recently in studies concerning control
of fugitive dust emissions.
     A simplified version      of the basic wind erosion equation is
given by
               Es = AIKCL'V
where          Es = suspended participate fraction of wind erosion
                    losses of tilled fields, tons/acre/year
               A  = portion of total wind erosion losses that would
                    be measured as suspended particulate
               I  = soil credibility, tons/acre/year
               K  = surface roughness factor, dimensionless
               C  = climatic factor, dimensionless
               L1 = unsheltered field width factor, dimensionless
               V = vegetative cover factor, dimensionless.
     The variable of  greatest uncertainty in the  adopted wind erosion
 relationship is the suspension factor A.  Only  limited test data is
 available to establish  the relationship of  the  suspension ratio of
                                                                  9
 eroded soil  with wind speed and soil type.  A review of this data
 has been conducted to establish best estimates  of suspension ratios.'
                                   3-24

-------
These estimates are listed in Table 3-5 for the major source categories.
The values serve as the current preferred basis for emissions compilation,
but should be considered tentative and subject to adjustment in the future.
      TABLE 3-5   FRACTION OF TOTAL WIND EROSION LOSSES WHICH ARE
                      SUSPENDED (DUST SUSPENSION FACTORS)Jป15
        Exposed Soil Surface Category       Dust Suspension Factor
                                               (Dimensionless)
   Croplands                                        0.025
   Unpaved dirt roads                               0.38
   Disturbed  native soil  (parking  lots,             0.38
   residence  yards, excavation  clearings)
     The remaining terms of the wind erosion equation reflect parameters
of the basic wind erosion equation as a result of 30 years of research
to determine  the primary factors that Influence erosion of soil by
wind.  The data base used to assemble representative values of the
erosion equation parameters is discussed in Appendix A.  When all terms
of the erosion model are quantified to reflect area-specific conditions,
the rate of soil erosion emissions is calculated for each definable
region of the emissions grid network.  This rate is then applied to
the number of acres of soil subjected to erosion in each of the defin-
able regions.
3.2.2  Soil Erosion Emissions From Specific Source Categories
     The major sources of wind-blown soil dust are unpaved roads and
parking areas, agricultural fields, undisturbed desert, tailings piles,
and disturbed soil surfaces.  Specific aspects concerning the estimation
of these wind-blown soil sources are discussed briefly below.
                                   3-25

-------
Dnpaved Roads
     The erodibility (I) of soil  surface of unpaved  roads  may  be  related
directly to the silt content of the road surface  (Figure A-l).  The silt
content of unpaved roads is determined by field tests  (Section 3.1.1)  or
by adjusting native silt content data available from USDA  soil  survey
results.
     The surface roughness factor (K) for dirt roads was assumed  to be
1.0.  It is not expected that the limited number  of ridges worn in dirt
roads would affect this overall estimate significantly.
     The climatic factor (C) is calculated to reflect seasonal varia-
tions in temperature, precipitation, and average  wind speeds for the
specific study area.  Table 3-6 is an example illustrating the signif-
icant seasonal variation of the cUmajtic factor associated with long-
term historical and 1975 meteorology for the Phoenix area.  These
differences  are due to  the transient moisture content of the soil and
the changing magnitude  of wind speed.  The Thornthwaite Precipitation-
Evaporation  Index  (PE Index) was formulated to express the net moisture
exchange between soil and  atmosphere.  The index is a measure of
cumulative moisture balance over the past  12-month  period  (See Table
3-6).
     The unsheltered distance  factor  (L1), for a given road surface in
the prevailing wind direction  varies continually.   To assess  an average
effective  distance factor, 1t  may  be assumed  that in the  long-term,
wind direction is  equally  distributed  for  all  roads.  Any  error attributed
                                   3-26

-------
                TABLE 3-6   SEASONAL CLIMATIC FACTOR, C, IN PHOENIX
                            AREA FOR J975 AND HISTORICAL LONG-TERM
                            AVERAGES.5
Period
1975
1st qtr.
2nd qtr.
3rd qtr.
4th qtr.
Historical
Averages
1st qtr.
2nd qtr.
3rd qtr.
4th qtr.
Quarterly
. PE* Average

8.8
8.8
7.7
5.3

9.4
9.4
9.4
9.4
Average Wind
Speed, w

7.2
8.4
8.3
7.3

5.6
6.7
6.5
5.2
C = .345 — ฃ-*•
(PEr

1.7
2.6
3.4
4.8

0.7
1.2
1.1
0.6
  *  PE ~ Thornthwalte's Precipitation Evaporation Index.
               PE = 10
                       12
where


and
                                   10
n.i
                          - precipitation-evaporation ratio
                            for month n
p ซ monthly rainfall  (inches)
e - evaporation (inches)
T = average monthly temperature (ฐF)
n - month under consideration
                                  3-27

-------
 to  this  assumption  would  be minimized by the more probable assumption
 that unpaved dirt roads are equally distributed in  terms of direction.
 For example, when the prevailing wind travtrser north-south roadways
 at  a 10ฐ angle,  the net effect  is  to balance the various cases of
 wind direction oblique to the road.  Figure 3-4 shows  the effect of wind
 direction to unsheltered  road distance  for a typical unpaved  road of
 25  foot width.  Figure A-2 relates the  unsheltered  distances  to the un-
 sheltered distance factor L1.
Q
ง
ง
Ul
CJ
0
s
ac
                                                    L25IJ
                                                     Road
                                                     Width
)1rect1or
                               30ฐ      45ฐ      60ฐ       75ฐ          90ฐ
                             ANGLE OF WIND WITH  ROAD (9)
                                                                   9
  Figure 3-4.   Effect of Wind Direction on Unsheltered Road Distance
  L'  1s related to  the  distance 1n which maximum son movement Is reached,
  and varies with soil  erod1b1!1ty.  The average value of L1 for road sur-
  faces of  specified credibility  IK, is shown in Table 3-7. It is evident
  that L1 varies only slightly for a relatively wide  range  of soil char-
  acteristics.   It  should  also be  noted that L1 approaches  zero from road
  silt levels  less  than 40%.
                                    o-t

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                       TABLE  3-7  UNSHELTERED ROAD DISTANCE
                                      FACTOR L'

     IK       L1  AT Different Prevailing Wind Directions      Average L'
              e  = 90ฐ   e = 60ฐ   e = 30ฐ  e = 0ฐ
     40       0.05      0.06      0.07     1.00                0.29
     60       0.08      0.09      0.10     1.00                0.32
     80       0.11      0.12      0.14     1.00                0.34

     A suspension factor of 0.038 is applied to approximate the suspended
portion of the wind erosion soil losses.  Table 3-8 summarizes the overall
computation procedure.   Emission rates of suspended dust arising from wind
over unpaved dirt roads are calculated by assigning specific values, as
discussed previously, to the parameters of the wind erosion equation.
These rates are combined with the total acres of unpaved roads in each
district or grid square to calculate emission totals by grid.   The emissions
are computed on a seasonal basis to reflect the significance of differences
in the climate.
Agricultural Fields
     Wind-blown dust emissions from agricultural fields are estimated by
assigning area-specific values to the variables of the wind erosion equation
(Section 3.2.1).   Except for the potential soil credibility (I), the emission
determinants depend on crop type.  In the process of the development of the
wind erosion equation, the U. S. Department of Agriculture has assembled
sufficient data to parameterize soil surface preparations and agricultural
practices for various crops.  These data should be employed to estimate crop-
specific soil losses in each identifiable district or grid square of the
study area.

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                                                  3-30

-------
     An overall  value for the soil  erodibility (I), is determined for the
agricultural  area of each township (or other convenient units of area) of
the study area.   Soil silt measurements conducted by the U.  S. Department
of Agriculture may be related to soil types identified on general soil maps.
Agricultural  regions are then located on the soil maps with the use of
aerial photographs.  An average silt content is estimated for cropland within
each geographical jurisdiction inventoried by weighting cropland acreage
and corresponding soil silt levels.  Average erodibility of the croplands is
then determined by the silt content/erodibility relationship shown in Appendix
Figure A-l.  This procedure may be simplified substantially if preliminary
analysis shows the study area is homogeneous in soil silt level.
     Values for the soil surface roughness factor (K), the unsheltered field
length (L), and the vegetative cover, are relatively uniform for a specific
crop.  The surface roughness factor accounts for resistance to wind erosion
due to ridges or clods in the field.  An optimal ratio of ridge heights to
ridge spacing will reduce soil erosion by a factor of 0.5.  Table A-l shows
typical roughness factors associated with soil preparation for various crops.
     Average field sizes for relatively flat terrain devoid of tall natural
vegetation have been established for various crops as shown in Table*-!.
Soil losses from wind erosion across a field vary from the windward edge
of the field and increase proportionately with length until  a terminal rate
of soil movement is attained.  The distance required before attaining maxi-
mum erosion rate is  influenced by the potential erodibility (I) and roughness
(K) of the soil.  The relationship between the unsheltered field length (L),
the surface erosion  potential (IK), and the field length factor  (L1)  is
shown in Figure A-2.
     The amount of vegetative cover residue left on a field after the growing
season varies appreciably by crop  (Table A-l).  Cover residue reduces soil
wind erosion losses  by the factor V as shown  in Figure A-3.  The degree of
                                  3-31

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reduction attainable with the crop residue is  related to the surface
erosion (IKCL1).
     The climatic factor (C), is calculated to reflect seasonal  variations
in temperature, soil moisture (including precipitation and irrigation
effects) and average wind speeds for the study area in the baseyear.  Calcu-
lations of C were illustrated in Table 3-6.   Regional values of C must be
adjusted for cropland soils to reflect additional soil moisture provided by
crop irrigation.   Periodic Irrigation during the growing season maintains
soil moisture and aggregated state of the soil.  The effects of the irriga-
tion are significant 1n the off-growing season, when disconsolidation of the
soil and exposure to winds would reduce resistance to soil erosion.
     Based on area-specific irrigation schedules obtained from local agricul-
tural agencies for the major crops in the area along with monthly precipitation
and temperature data, a PE Index 1s calculated for each crop.  (Irrigation
water is treated as equivalent to rainfall.)  The PE values are then combined
with baseyear monthly average wind speeds to calculate climatic factors corres-
ponding  to the non-growing or erosion-susceptible period  (obtained  from local
agricultural organizations).  An example  of the  results of these calculations for
a study  of the Phoenix  area  1s  shown  in Table 3-9.
                                  3-32

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1
1






1






1

1
mf
1

1

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Table 3-9. CROP-SPECIFIC CLIMATIC FACTORS
IN PHOENIX AREA9




CROP PE INDEX NON-GROWING
OR EROSION
SUSCEPTIBLE PERIOD

Cotton 58.0 All Year
Alfalfa 113.0 None

Barley 52.8 May - December
Sorghum 40.2 November - July
Wheat 54.9 May - December


AVERAGE CLIMATIC FACTOR

(FOR PERIOD OF VULNERABILITY)
W3
C . .345-^ 2


.05
w

.06
.10
.06

Estimates of suspended dust arising from soil wind erosion losses
are calculated based on assignment of wind erosion equation parameters
as specified above. A suspension factor of
approximate the suspended portion of the soi
summarizes the overall computation procedure
0.025 is employed to
1 losses. Table 3-10.
for a series of five
example crops. The calculations should be computerized for convenience
in dealing with areas having numerous townships containing agricultural

fields. Values of the credibility index I,
length factor L1, and the vegetative factor
curves of Figures A-l, A-2, and A-3.



3-33

the unsheltered field
V may be extracted from the






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                                       3-34

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I

I
             Disturbed Soil  Surfaces
™                Estimation of wind erosion emissions from vacant and cleared property
•           is conducted by assigning area specific values to the terms of the
             equation.  Area-specific values of the disturbed soil properties are likely
I           to vary substantially from district-to-district, or from lot-to-lot.  A
             survey of vacant lots, parking lots, and dirt residence yards may be
I           required to establish representative characterizations of these sources in
_           the various identifiable geographic areas.  This survey may be accomplished
•           by field visits, use of aerial photos, or special summary data available
•           from local planning agencies or service organizations.  The level of effort
             associated with acquiring a representative data base should be dependent on
I           the apparent impact of the sources on air quality in the area.
              Tailing  Piles
I
_                 Tailing piles consist of deposits of earth removed during mining
"           operations.  For large mines, the tailing piles may expand over several
•           thousand acres.  Generally the piles are composed of substantial pro-
             portions of fines and are relatively susceptible to significant wind
•           erosion losses.
                  Only limited information is available concerning soil emissions from
I           tailings piles.  Recently, PEDCo 15  has developed an emission factor for
_           this fugitive source by employing the wind erosion equation.  No field
•           testing was performed in the PEDCo analysis.  Representative characteristics
•           were identified for tailings for use in the wind erosion equation.  The
             piles were described as being composed of sand and loamy sand soils with

I
I
                                               3-35

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possible fines for surface cementation  (I  =  130),   They  are  characterized
by a smooth, unridged surface (K = 1) and  no vegetative  cover (V  -  1)..
Wind fetch over the piles is approximately 2000 feet.  Ten percent of  the
soil loss estimated by the wind erosion equation is assumed  to become  sus-
pended.  The emissions are seasonally related to the climatic factor,  which
may vary substantially during the year.  The effect of climate on  the  emis-
sion rate 1s Illustrated in Table 3-11.  Total emissions are calculated by
applying the emission factor to the number of acres of tailings pfies-.
     Soil erod1bH1ty, vegetative cover, roughness factor5 and wind  fetch
may be adjusted to reflect tailings piles of various characteristics,
However, typically it 1s difficult to obtain detailed Information  t* cham
terize the piles.  It is anticipated that a  survey of individual inlnjs nTH
be  required to obtain the needed data.   This effort may be a 1 located accord-
1flg to the apparent signfftctnce of tfie tailings piles in ISP lev(*V,
                                   3-36

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TABLE 3-11. EMISSION FACTORS FOR TAILINGS PILES
(NO VEGETATIVE COVER)
Emissions
Climatic Factor tons/acre/year
.30 4.0
.40 5.3
.50 6.6
.60 8.0
.70 9.5
.80 10.5
.90 12.2
1.00 13.3
1.20 16.0

It is assumed that the particles size distribution of tailings piles
emissions is equivalent to that of emissions from aggregate loadout opera
tions.

Particle Size (ji ) UQH^* pprrpnt_
<
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3.3  PROJECTION OF FUGITIVE  DUST EMISSIONS
     The extent and nature of fugitive dusi emissions depends on the
human activities which create or influence the.e sources.  As the
community experiences development and reshaping, sources of fugitive
dust are being altered in magnitude, location, and type.  If control
strategies are to be devised to correct air pollution problems, it is
essential that these air pollution problems be characterized to reflect
the future environment, when strategies would be implemented.  There-
f
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I
I
I

I
                 Since  the  specific  data  base encountered for any  study arpa win
•          vary  significantly, the  forecast indices which may be  used to determine
S            projected emission  levels will also vary.
            Unpaved Roads
I               The parameters needed  to calculate dust emissions off unpaved
_          roads are discussed in Section 3.1.1.  Two of these  parameters may
*          change significantly  in  future years.  They are  1) mileages and  dis-
•          tributions  of unpaved roads,  and 2) average daily traffic.
                 The changing mileages  of unpaved  roads in various sectors of
|          study area  may  be indicated by identifying trends in the  historical
_          data.  Additionally,  plan  forecasts and future objectives of  the local
•          transportation  department  should be obtained.  Road  improvement  pro-
JA          grams will  have significant impact on  the status of  unpaved road mile-
            ages  in many cities.   Generally the target areas and schedules for
•          such  improvement programs  are outlined in detail, and can be  employed
            directly to adjust  the baseyear parameters used  in estimating the base-
jj          year  emissions  (see Section 3.1.1).
m               For many cities, improvements in  county and city roads may  be
            occurring with  some uncertainty, depending on the annual  budget  and
•          most  pressing maintenance  or  new development requirements.   In this
            instance, average budget trends may be assumed to approximate the
|          expected extent of  roadway paving, each year, and  location  of these
            improvements may be approximated by assuming tneir occurrence witm'n
3-39

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anticipated growth areas specified on city and county planning maps.
Distribution of the expected mileage of road paving throughout the
growth belt areas may be expediently tabu!:Led with the use of isoline
overlays depicting incrementally expanded development arฐas for the
period from the present to the years of interest.  A detailed explan-
                                                          9
ation of this overall approach is documented in reference  .
     While road improvements may reduce dust emissions on  unpaved roads,
Increasing traffic in future years will tend to offset this benefit.
The projected ADT for unpaved roads may be assumed to be directly
related to expected population growth for the area.
Agricultural Till ing
     The most suitable  index of agricultural growth 1s reflected by
the historical trend of cropland acreage.  When agriculture exerts a
major Impact on the economy of an area, the trend rate will probably
remain fairly constant  1n the near term.   Inspection of previous and
future land use maps for the area will  Indicate  the changing  location
of croplands.  Projections are made  by  comparing the present  location
of croplands with the future expected locations on the land use maps.
      If appropriate, available historical  agricultural data may be
evaluated  to Identify apparent trends  in  crop  types.  Changes in  crop
type will  affect  the tillage season  and would  impact the  temporal
distribution of emission  levels  from croplands.  Local USDA officials
may  be  able  to provide  an assessment of any  changes  in projected
crop  types.
                                    3-40

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I
                           4.0  EMISSIONS/AIR QUALITY RELATIONSHIP

                 This section provides an outline of general procedures which may be
™          used as a guideline in formulating an appropriate source-receptor rela-
•          tionship for areas where fugitive dust sources are prevalent.  The pro-
            cedures presented here should be considered tentative and should not
fl          inhibit incorporation of modifications and improvements.  Section 4.1
            concerns some important considerations affecting the choice of the source-
•          receptor relationship.  Section 4.2 discusses several air quality models
            that have been used for fugitive dust modeling and others that could be
•          adapted for use.
•          4.1  SOME FACTORS AFFECTING SELECTION OF THE SOURCE-RECEPTOR  RELATIONSHIP
                 The evaluation of air pollution control strategies requires a detailed
•          understanding of the relationship between emissions and ambient air quality.
            This subsection considers the importance ofiaveraging time and source config-
m          uration for selection of models applicable to fugitive dust.
H          4.1.1  Averaging Time
                   An essential aspect in selecting a source-receptor relationship
•          concerns the averaging time of the air quality predictions.   There is reason-
            able cause to restrict the analysis to only the long-term averages.  First,
I          greater control is typically required to attain the primary annual standard
g          than to attain the 24-hour standard (provided episodes due to dust storms
*          and accidental industrial emissions are excluded from consideration, as
•          allowed by SIP regulations).  A second reason for restricting the scope of
            the model to long-term considerations concerns the uncertainties associated
I
I
t
4-1

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with the data base.   Uncertainties are introduced at several  stages  of
the air monitoring measurements, the emissions  inventory compilation,  and
model formulation.  The analytical limitations  associated with the
detailed documentation of short-term particulate origins and  their rela-
tionship to air quality levels would increase the uncertainties greatly,
making the substantial additional effort needed for this task impractical
and unwarranted at this time.
4.1.2  Source Configuration
       The nature of the source 1s an Important criterion to  be considered
in the selection of a source-receptor relationship.  For conventional  well-
controlled paniculate emission sources, where most of the partlculates
emitted are typically smaller than 10vW in diameter, the source-receptor
relationship may be established through the standard equations for atmos-
pheric transport awl dispersion.
       However, the application of currently available models to the fugi-
tive dust problem 1s further complicated by the  ill-defined nature of the
sources themselves.  It  is often  difficult to characterize the sources  in
the  traditional classifications as: point, area  or  Hne.  Also, certain
commonly used emission terms such as  exit velocity  and effluent tempera-
ture may become Inappropriate parameters in this context.  These potential
ambiguities, of source type and emission characteristics, are  Inherent  to
the  application of  any currently  available model.   They  must  be dealt with,
by the user, on a case-by-case  basis.
        Unfortunately,  typical Gaussian-type  dispersion models  may not
 properly consider the  physical  characteristics  or  the emissions of  unpaved
 roads, storage  piles,  resuspended street dust  or other  fugitive dust
                                    4-2

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I

I
               3.3.2  Wind Erosion Sources
I                 The major sources of fugitive dust which are suspended by wind
               are  agricultural  fields, unpaved roads, undisturbed desert, tailings
I             piles, and disturbed soil surfaces.
•             Unpaved Roads
                   The procedure  for estimation of projected wind erosion emissions
•             from unpaved roads  is the same as that outlined in Section 3.2.2.  The
               adjustments which must be applied to the baseyear parameters used in
•             the  wind erosion  equation include:  1) the miles of unpaved roadways
               in the various grid sectors,  and 2) the climatic factor.  The former
I             item is obtained  by the  considerations outlined in Section 3.3.1.  The
.             climatic factor is  calculated to reflect representative meteorology
'             for  the area, based on historical data for temperature, precipitation,
•j             and  mean wind speed obtained  from the National Climatic Service.
               Agricultural Fields
•                 Due to changes in location, acreage, crop types,  and climate,
               the  estimates of  agricultural wind erosion emissions performed for the
•             baseyear  (Section 3.3.3) should be repeated  for the selected future
_             years.  The considerations  outlined in Section 3.3.1 are applicable to
™             the  issue  here:   crop type  by grid sector, and acreage by grid sector
•             must be determined. These  inputs are utilized to derive appropriate
               values for the  terms of  the wind erosion equation.  The climatic
•             factor is  adjusted  to a  representative historical value for the area
               if necessary.
I
I
a
3-43

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 Disturbed Soil Surfaces
     The major consideration associated with the projection of emission
loadings from each of these sources involves changes in spatial distri-
bution and total source area.  Projected development reflected by the
general plan will indicate acreage changes and location for undisturbed
desert areas and disturbed soil surfaces.  Potential procedures for
 approximating  these changes  are similar  to  those discussed under
construction (Section 3.3.1) emissions estimation.
                                   3-44

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 I
 I
 I
 I
            Construction Activities
                 Forecasted construction activities should be based on the general
             future  land use plan for the study area.  Land areas  involved in
             construction for  orojected years are assumed to  be consistent with the
 •           forecasts of the county general  plan.  Based  on  the annual area of
             new  urbanization development,  and an  assumed  duration  for active con-
 I           struction on this area, a  total  dust  loading  may be estimated for
 m           future  years of interest.   The location of  the development will proceed
 •           according to the scheme shown  in the  general  plan.  A geometric mapping
 •           procedure may  be used  to estimate the projected  location of  the con-
             struction activity.   Isolines  reflecting  the  constant rate of expanding
 I           development may be  constructed for specific future years by  interpo-
             lating  between the  boundaries  of the  existing developed area and  that
 ฃ           developed area forecasted  by  the Future General  Land  Use Plan.  The
             differential development in the years projected  for example  may
 •           then assume to occur within a  growth  belt representing the expanded
 •           urbanization over  the  specified 5-year period.   The  forecasted  dust
             emissions  loadings  are apportioned according to  the  relative area of
 I           the  growth  belt  in  each of the grid  squares of the emissions grid
             network.
             Aggregate Storage  Piles
 •                Historical employment trends in  the  mineral industry  are a relatively.
             accurate  index of  Increasing  area of  aggregate storage piles.   These employ-
K           ment data are  available from  state economic organizations.   Frequently,  the
             compilations arc presented with projections which can bo used directly in
I
I
                                                3-41

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adjusting the baseyear emissions levels to those forecasted for future years.
Potential relocation or new storage operations may be identified by consulta-
ion with cognizant local agencies such as the zoning and planning department,
the construction industry, or the mineral industry itself.

Entrained Street Dust
     Roadway improvements, expected to be implemented over the next
ten years, will have significant impact on street dust loadings.
Improvements consist of upgrading currently paved streets,  paving of
dirt roads, new road construction (both paved and unpaved), and curbing
and sidewalk construction.  While all of these Improvements will result
in lower dun loads on existing streets, the Identifiable change
which will most affect street dust loadings from existing roads con-
cerns the decrease in number of miles of uncurbed roads.  (The street
d'us-t loading* for roads with uncurbed road shoulders is four times less
than that observed for curbed streets.)
     Projections of vehicle miles traveled (VMT) for future specific
years are assumed to be directly related to population projections.
These projections are used to adjust the VMT for the existing traffic
 network to future year levels.   The  adjusted emission  factor reflect-
 ing newly curbed streets  is  calculated by weighting the emission factors
 for uncurbed streets and  curbed streets relative to the proportion
 of each of these street configurations in those future years.
                                  3-42

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t
             sources.   Nor  do  they normally consider gravitational settling or dry and
M           wet  deposition of participate matter; pollutants are typically treated as
             though  they were  unreactive gases.   Gravit'.tional  settling and dry deposi-
m           tion become increasinqly  important as the diameter of the particles
m           exceeds about  10  \m. Available data  indicate  that  fugitive dust emissions
             in some areas  (for example, the anv  southwest) may have a large proportion
W           of mass in the range of 20-70+ vim. Therefore,  application of  conventional
             Gaussian plume models may be  inadequate for air  quality evaluation where
•           fugitive dust  sources predominate and where particle sizes are generally
             large.   These  caveats notwithstanding, the following subsection outlines
8           some modeling  techniques  that should prove to be useful in assessing  the
ซ           fugitive dust  problem.
             4.2   DESCRIPTIONS OF SUGGESTED AIR QUALITY MODELS
•                The discussion in this section  focuses on several models that have
             been used or that may be  adopted to  evaluate  the impact of fugitive dust
I
sources.
m           4.2.1   AQDM and CDM
                    Two models  that  are  applicable  and available for estimating  the
1           annual  impact of conventional  sources  on  the ambient air quality  are  the
             Air Quality Display Model  (AQDM)  and the  Climatological  Dispersion  Model
|           (CDM).   (The format of  the  required input parameters and the necessary
                                                 2           3
—.           data base are documented in the AQDto   and CDM     User's  Guides),
™                  These models have been  used for a  number of years to relate  parti-
•           cle emissions to ambient TSP concentrations.  For the most  part,  because
             of the lack of basic emission  data with respect to fugitive dust  sources,
I           such sources were not directly considered in these models.   Such  sources

I

I

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have been considered in an indirect manner through the regression analysis
of observed and model-predicted concentrations.   The Y-intercept resulting
from that analysis has generally been assumed to be the contribution of
those sources not directly input into the model, plus background.  In
urban areas where smaller sized particles predominate, (e.g., Chicago,
Philadelphial AQDM and COM may still represent the best approach (at the
present time) for developing a source-receptor relationship.
       In those areas where fugitive dust sources predominate, such as 1n
the west and the arid southwest (e.g., Phoenix, Las Vegas, etc.) AQDM and
COM are of limited value; other models outlined in following discussion
may be adapted for these cases.
                                                          29
4.2.2  The Atmospheric Transport and Diffusion Model (ATM)
       The ATM 1s a receptor-oriented,mlcro-mesoscale (100m - 50km), clima-
tological, flat terrain, Gaussian plume model with a particle deposition
                                                                          30
option.  The dispersion coefficients a^-e calculated from Pasquill-Pifford
                                31                        32           33
stability parameters or Hosker's     formulation of Briggs     - Smith
dispersion parameters using surface roughness.  Plume rise  is calculated
             34
using Briggs'     formula.  At a given receptor, the model  computes the con-
tribution, for time periods of one month or  longer, from each source  (point,
area and line) to the ambient air concentration  (yg/m3).  Also included in
                                                                       2
the output are the dry deposition rate and the wet deposition rate  (g/m /s)
for each source at each receptor.  The wet deposition  rate  is a  function  of
the  rainfall rate and  frequency of  occurrence.   The  dry deposition  is  com-
puted by assuming fractional,  rather  than complete,  plume reflection  at the
surface; the percent  reflection depends  on the  type  of ground cover.   The
gravitational  settling of the  partlculates is accounted for by  lowering the
effective  height  of emission,  "tilting  the plume",  based  on the  distance  to
                                 4-4

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             the receptor, the mean wind speed and the terminal velocity of the particle.
  •                The meteorological input to the model consists of the usual stability-
             wind rose frequency data, fraction of the time during the period of record
  |         that precipitation occurred and average rate of precipitation (in hundredths
  fc         of an inch per hour).
  •                The point source data must include emission rates for all sources in
  •         g/s, stack heights, exit gas temperatures, volume flow rate (or stack diame-
             ters and exit velocity), and source locations in UTM coordinates.
  f                Line source data consists only of the emission rate in g/m/s, height
             of the line source, and the UTM coordinates of the line end points.
  •         Receptor locations, likewise, are specified in UTM coordinates.
                    Modeling of gaseous pollutants requires that the boundary layer
 Ji          thickness and gas diffusivity be specified while modeling of particulates
 m          requires specification of particle diameters and densities.  This imposes
             a potential limitation on the application of this model because reliable
 ft          particle size and particle density data are generally limited.  The fact
             that the model considers particle size and particle deposition makes the
 |          model appealing for use 1n areas with sources that emit larger-sized dust
             particles.  However, at the present time, severe restrictions over and
 m           above the basic data input limitation previously described exist which
 ป.          limit the general usefulness of this technique to the fugitive dust problem.
             First, the model does not have the capability to handle a large number of
 V           sources or receptors, and hence, would be severely limited as a regional
             scale model unless significant revisions were made.  Second, if the detailed
 •           particle density and particle size spectra are not available, the deposition
             and gravitational settling modes of the model cannot be used.  Finally, in
I           its current form the model is of limited use for establishing control

I

I                                            4"5

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strategies because of the output format and lack of source contribution
tables.
4.2.3  Hanna-Gifford Model
       The Hanna-Gifford model is an area source model  that accepts a
gridded emissions inventory.  The elements of the emission grid must be
square and they must be of uniform size; however, the specific size is vari-
able (a typical example would be a 2 km x 2 km grid).  It is possible to
incorporate physical removal mechanisms (deposition) with minor modifica-
tions (see Appendix B for a detailed discussion of the model).  In those
regions where conventional we 11-controlled point sources are present, the
Hanna-Gifford model must be supplemented by one of the models described in
4.2.1 or 4.2.* and the results superimposed.
                                                             •jr  -3C  O7  OQ
       The basic model has been used in several case studies   '   '
in which the comparison of modeled and predicted concentrations has been
examined in detail.
4.2.4  Modified CDM/Rollback Model
       A necessary but not sufficient feature of a fugitive dust model is
                                                                     39
the requirement that it accommodate  a  range of particle sizes.  TRW
developed a modeling procedure that uses the COM to model that portion of
the emissions  comprised of particles smaller than 20  ซm and uses  a propor-
tional (rollback) analysis to  represent the contribution of the larger
particles.  The rationale being that the COM is a suitable model for
describing the dispersion of  particles smaller than  about 10 ym  diameter.
However, the COM  1s  presently  unable to account satisfactorily for the
dispersion-deposition behavior of larger particles characteristic  of  fugitive
dust  sources because  it  does  not  contain techniques  such as those  developed by
               40                       41
Van der Hoven      and Dumbauld, et al.      or  procedures such  as those
                                    4-6

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1
            incorporated  in  the  Atmospheric  Transport Model.
•                 In  order  to facilitate  this  modified modeling approach  (see
            Appendix C for model  description and  Appendix  D  for model  input  require-
•          ments),  the gridded  emissions  inventory  is prepared for  four  particle
m          diameter ranges  reflecting the cut-off points  in dispersive behavior;
                        0 -  10 ym
•                     10-20 ym
                       20 -  70 ym
•          greater than    70 urn.
                   The COM may be applied  directly to  the  first two  ranges since
|          diffusion  and atmospheric turbulence  effects play a major role in the  move-
ซ          ment of these particles.   However,  for the 10-20jjn size  range, the effect
*          of gravitational settling is approximated with the assignment of a decay
•          constant in the  COM.   The explanation of the derivation  of the decay con-
            stant is given in Appendix D.
•                 The emissions of particles greater  than 70ymin  size are  ignored in
            the air quality  model.  The fate of these  particles will  be determined
|          almost exclusively by gravity  effects.  The range of horizontal  travel of
^          these particles  is only a few  meters, generally  not enough to impact the
™          air quality monitors, except for those cases where the  local  source is very
tf          near the monitor.
                   This technique appears  useful  because  it  applies  an atmospheric
•          transport and dispersion model to that portion of the  fugitive dust emis-
            sions that can be so treated and because it provides a  technique for approxi-
jj          mating the impact of the emissions of larger  particles.   The  technique has
^          not been widely  applied and should be used with  caution.   Appendix E pro-
•          vides a sample application of  the CDM/Rollback Model.

I

1

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4.3  SUMMARY
     At the present time, the consideration of fugitive dust sources in
diffusion models is limited.  Continued use of AQDM and CDM appears to be
the most reasonable approach for those are?s where particles less than
10 micrometers predominate.  Other techniques may be more useful  in those
areas where larger sized particles are common (e.g., west and artd south-
west).  The procedures included herein should not be considered inclusive
and should not inhibit the development and incorporation of various modi-
fications and Improvements.
                                   4-8

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I
1
5.0 ALTERNATIVE CONTROL MEASURES
fl                 In areas where fugitive dust is the cause of high levels of TSP, the
            major sources are typically unpaved roads, construction activities,
ff          re-entrained street dust, and suspended soil eroded by wind off vacant
            lots and disturbed soil surfaces.  While the impact of these sources is
m          generally localized in nature, they are typically found throughout a
_.          given area and therefore may create widespread problems of high TSP concen-
*          trations.  However, several other sources of fugitive dust (i.e., tailing
•          piles) are generally less widespread and create more of a truly localized
            limited  Impact for a specific area.
•                 In order to determine the impact of the sources most responsible for
            the high TSP levels at various monitoring sites for the baseyear and
I          projected years, 1t 1s necessary to review the emission inventory and
—          modeling results which have been previously discussed in Sections 3.0 and
™          4.0.  A review of these results will establish the significant sources
ฃ          for which alternative control options should be investigated.  The control
            options for various fugitive dust source categories are outlined below.
•          5.1 Control of Dust from Unpaved Roads
                   Control methods to reduce dust emissions from unpaved roads consist
I          of  (1) paving roads, (2) application of chemical stabilizers,  (3) watering,
—.          and (4) traffic-related controls.  Some communities have experimented with
™          these alternatives and may be considering the implementation of these
•          measures in the general plan for the area.  Relevant county and city depart-
            ments should be consulted to identify prospective planning efforts with
ป         potential air quality  impacts, and to obtain data which would  help charac-
            terize dust control applications for unpaved roads in the study area.
i

i

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                42
       A study      was  recently completed ir. wHch various chemical  stabrH/vzers
were tested for dust control  on  unpaved rfK.ds.  Th? stabilizers  were
applied to sections of an  unpaved roao wnh a;i  average da-.'iy  traffic
(ADT) of 140 vehicles and  a  surface soil si'U co-rc^ii; of  ?J.s%-   Sosno or
the chemicals were applied by spray, v^.ile cc.ws were mixed  to  a inreu-
inch depth after ripping  the  roacibsd survace,  .-ii-vo'. ana  dim: collector
measurements were utilized to evaluate -cha dust-suur^ssing abVircy or the
stabilizers with  the rtat  subject to '.v-^al trarnc i;o>r,Li;n:Ms.   The
performance of  the stabl 1 ', zev products '
-------
I

*           Emulsion,  which was controlling  dust  emissions  by 84.4%  after  a  14-month
•           period.   The main drawback  to  use  of  the  effective stabilizers is  cost.
             Repeated applications of the chemicals, even  at reduced  rates, impose
I           costs which approach or exceed the annualized cost of a  paved  road.
                    Paving of roads clearly offers the most  effective long-term dust
|           control.  The most widely used low cost pavement is the  bituminous
_.           asphaltic chip seal over a  granular base  or a stabilized soil  base.
•           Figure 5-1 shows a profile of  this chip seal  construction.   A  penetration
A           stabilizer (liquid asphalt MC-250) is applied to the 6-  to  8-  inch
             base, followed by a chip seal.  Maintenance requirements depend on vehicle
•           traffic and locale, but generally include a second chip  seal after one
             year, followed by another seal in approximately 5 years.
                                                                                   ซ26
                    A study conducted by the  city of Seattle Engineering Department
—           has shown the most cost effective method  of dust control on Seattle road-
™           ways is a chip seal when the average dally traffic is over  100 vehicles.
•           This dust control option is also economically beneficial, considering  the
             estimated annual savings of $2,665/yr/mi  in maintenance  costs  resulting
•           from the measure (annual maintenance costs of roadways diminishes apprec-
             iably with the quality of the  road surface) and numerous other cost benefits,
|           such as reduced sewer costs, higher property values, lower  vehicle operating
ซ>          costs, lower health costs, and reduced cleaning costs.
*                  The cost of the various types of road paving and dust palliative
•           alternatives varies from one region to another.  Construction, maintenance,
             and material costs contrast significantly between regions.   Typical cost
•           of initial installation and maintenance for various dust control alternatives
             in Maricopa County (Arizona) is shown in  Table 5-3.  Actual costs for any
I          given study region should be determined by inquiring with the  local trans-
—          portation departments.
 I                                              5-5

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IQ1L
                            Exfefina Base Material
        Figure 5-1.   Profile of Typical Section for Chip Seal Road
                     Surface Construction
                                      5-6

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                          TABLE 5-3.  INITIAL COST AND MAINTENANCE COST
                                      fOF ALTERNATIVE ROAD SURFACES APPLIED &9  77
                                      BY MARICOPA COUNTY HIGHWAY DEPARTMENT *'   .
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ROAD SURFACE TYPE
Gravel Road
Oiled surface (low cost Applica-
tion)
Oiled surface dust control oil
Chip seal coat
3" asphalt
INITIAL COST PER MILE
$
$
$
$
$
16,000
2000-3000
5,300
35,000
55,000-100,000
ANNUAL MAINTENANCE t
1
$
$
$
$
$
600
2000-3000
5,300
800
160
U              Control efficiency estimates for the various dust measures arc tabulated
           by considering the effect of altering a road which is presently an unpaved
•         dirt surface having a silt content representative of the study area.  Cost
m         effectiveness is then estimated by considering the annualized cost of the
           measure in the given study area and the resulting emissions reduction.
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Efficiencies and cost effectiveness estimates are shown in Table 5-4.   The
chip seal  surface appears to be somewhat more cost effective than the other
road surfacing dust control  measures, and of those measures providing the
best control, the chip seal  is significantly more cost effective.  These
                                                      26
findings are consistent with the Duwamish Valley Study      where it was
found that the least cost control  was a chip seal surfacing when ADT is 150.
However, when ADT decreases  to 15, lighter applications of the road dust
palliatives may be used to attain a certain level of dust control and cost
effectiveness of the palliative in this instance becomes competitive with the
                                    5-7

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chip seal paving approach.  It should be notod that the cost figures of

Table 5-4 are presented for illustrative pur, oses, and may vary greatly

depending on locale and existing construction and road maintenance practices.
      TABLE 5-4.  EFFECTIVENESS OF ALTERNATIVE ROAD SURFACES IN REDUCING
                  DUST EMISSIONS FROM AN UNPAVED ROAD IN MARICOPA COUNTY.
                  ARIZONA
ROAD TYPE
01 rt Surface
Gravel
011 Surface (Dust Control
011)
Oiled Surface (Low cost
Application)
Chip Seal
Asphalt
EMISSION RATE
LB/VEHICLE MI.
22a
lla
5f

11^

oe
oc
ANNUAL
EFFICIENCY
—
50%
75%

50%

100%
100%
COST EFFECTIVENESS0
$/TON OF DUST
—
11.0
19.5

13.5

10.8d
19. 6d '
b.

c.
                                  44
                                         and road silt content of 24%  and
Based on AP-42 emission factor
average vehicle speed of 35 mph.
From reference   •
Computations based on assumption  of ADT of 100, maintenance costs  of
Table 5-3, and annuallzed cost for Indefinite period at 10% interest.

These figures do not Include the  dust reductions attained by Inducement
of traffic off unpaved roads to the newly paved surface.
This emission rate does not Include entrapment of dust loadings off the
pavement.  Entrained dust emissions are discussed 1n Section 3.1.2.
                                                                     42
Based on field test conducted by Arizona Department of Transportation  .
                                    5-8

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                 Traffic  controls  also offer potential  for  dust  emission  reductions
 1         from unpaved roads.   Dust emissions  increase  exponentially with  vehicle
                              OC   OT
 ป         speed up to 30 mph  '    .      Table  5-5 illustrates  the  dust emission

 *         rate at different speeds  for a vehicle travelling over a dirt road.

 •         Based on an average  speed of 35 mph, the reduction achieved  by restricting

            vehicle speed to 20  mph would be 62  percent.


 •              Restriction in  use of unpaved roads may  also be employed to reduce

 ฃ         dust emissions.  Unpaved  roads may be closed  to travel when  alternative

            paved routes are available.   The potential  of this dust  control  measure

 I         is not encouraging since  almost all  roads provide needed access  to at

            least a limited segment of the population,  and it is not plausible to

ฃ          restrict traffic to  only  this limited sector.  It should be  noted, however,

            that traffic volume  on the remaining interior unpaved roads  will be diverted

•          significantly after  addition of paved routes  to the  road network.  Such

m          traffic inducement should be considered in assessing the total effectiveness

            of the road-surfacing measures.  For example, a plan to  pave half the

ป            section Hne roads in Maricopa County (Arizona) by 1985  would reduce
                                                                              45
            expected traffic on  remaining Interior unpaved roads by  15  percent  .
            This analysis is made by considering the trip alternatives in a representative

            section of the road network for the "before and after" paving control  measure.
                                                5-9

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           TABLE 5-5.  DUST EMISSION RATES MT DTFFERENT VEHICLE SPEEDS
SPEED OF
VEHICLE
35
30
25
20
EMISSION RATE3-
LB/VEHICLE MI.
22,0
19.0
13,0
8.5
DEGREE OF EMISSIONS
REDUCTION
—
14%
41*
62%
                                                            44
a.   The emission rate is  based on  the, AP-42 emission factor      for vehicle
    speeds  of *Q mph and  over.   For speeds  from 0 to  30 mph  the emission rate
    increases exponentially with speed and  is  calculated as  follows:  e = .0211  SS
    wnere e * emission rate (It/vehicle mi),  and S ซ  vehicle speed  (mph).  The
    baseline emission rate (35 mph) was calculated assuming  a typical dirt
    road s1 It level  of 24*.
5.2  CONTROL OF ENTRAINED STREET DUST
     Various field studies have indicated that dust emissions from paved streets
                                                                    46
are a major component of material collected by high-volume samplers.    Re-
entrained traffic dust has been found to consist primarily of mineral matter
similar to common sand and soil, mostly tracked or deposited onto the roadway by
vehicles, but also including engine exhaust, from wear of bearing and brake
Itntngs, and from abrasion.  These forms of dust may settle to the street sur-
face and become subsequently reentrained.  The patterns of tiiaterl*! deposition
on the street suggest the control of entrained street dust by two principal
methods:  1) control of the street dust origins, and 2) street cleaning.
                                     5-10

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Control  of the Dust Origins
     One obvious means of reducing street dust loadings  is  by controlling
its origins.   Significant origins consist of carryout of dust from dirt
surfaces by motor vehicles, atmospheric fallout of airborne particulates,
and transport from adjacent exposed land areas.  In areas experiencing
arid climates, the major sources of street dust originate from transport
of exposed soil from areas near the streets (i.e., unpaved road shoulders).
Dust from the exposed road shoulders is transported to the street surface
by turbulence from passing vehicles, wind erosion, tracking by pedestrians
and vehicles, and water runoff.  Soil carryout by motor vehciles is also
a significant cause of street dust, particularly in areas with abundant
rainfall.

     In many areas, roadway improvements anticipated in the next several
years will result in significant impacts on street dust loadings.  These
improvements are important because dust loadings for streets with uncurbed
shoulders are estimated to be four times greater than that observed for
              47
curbed streets   •  The substantial portion of curbing and gutter
improvements will occur in the cities.  Since the  major  portion  of
vehicle miles traveled in any area are concentrated within the cities, the
urban street improvements will have far greater impact on TSP levels than
would similar improvements implemented in county road networks.  Accordingly,
intensification of the street improvement plans should be considered as a
potential control for street dust emissions.
                                    5-11

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     To increase the effectiveness of street curbings as a dust control
measure, the adjacent soil should be stabilized or covered to prevent
wind erosion or tracking of this soil onto the street.  Clearly, the
most effective means of soil protection at the curb is a sidewalk.   A
typical and desirable city policy is to include sidewalks whenever curbs
are constructed on major streets.  The effectiveness of this measure has
not been quantified, but 1t is expected that transfer of exposed soil to
adjacent road surfaces will be decreased significantly.
     Typical city construction costs for street curbs are currently
about $5 per curb foot.  The cost of sidewalk construction is $6 per
                                                48
running foot of a standard 5 foot wide sidewalk
     In cities where sanding 1s used on streets for snow and ice control,
modifications can betmade in the sanding operations to reduce air quality
impact without Increasing the hazard of vehicle accidents.  Some of these
modifications are:
     .  replace the sand with salt or a salt/sand mix;
     .  plow streets instead of  sanding;
     .  clear the sanding material from street  as soon as possible after
        each storm;
     .  apply material  only at  intersections  and  on  hills and  curves
        (reduce the amount applied);
      .  use sand  that  has been  washed  and  sized.
 It 1s  not  possible  to  quantify  the  air quality  Impact of each  of these  changes
 or their  combinations,  but the  simple  assumption  could be made that  the impact
 from sanding would  be  reduced  proportionately to  any reduction in  the amount
 of sand used on  a  street  in a  given  area.
                                    5-12

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Street Cleaning
     There are three main types of machine street sweepers  currently in use.
Broom sweepers utilize a rotating gutter broom to sweep material  from the
gutter into the main pickup broom which rotates to carry the material into
the truck hoppers.   The broom sweeper is by far the most commonly used class
of sweeper.  A second type of sweeper, called the regenerative air sweeper,
uses an air blast to direct material  into a collection hopper.  A third type
of sweeper utilizes a broom and vacuum system to collect material.  Each of
the sweepers employs a water spray to control dust emissions during sweep-
ing.  In addition to machine street sweepers, various cities use flushers
which use a jet of water to move material to the gutter rather than actual
material pickup.
     Broom sweeping has two operational characteristics that make its use
alone of doubtful value-—it moves material from the gutter back into the
street for pickup and it is not efficient in removing fine particles that
aremost susceptible to re-entra1nment.  Flushing probably shows the most
promise with regenerative air and vacuum sweeper somewhere in between for
reducing re-entrained dust.  It wets the otreet, causing dust suppression until
the surface is completely dry, and moves material out of the traffic lanes to
the gutters.   The only  practical  limitation  on  the use of flushers  is  in  areas
where water availability  is  restricted.   Flushers use 3,000 to 4,000 gallons
of water per mile of  street, or up to  70,000 gal/day.  Therefore, street  flush-
ing could  easily constitute  1  to  2 percent of a  city's total water  consumption.
                                               14
      In a  recent field  study performed by  PEDCo   for EPA in Kansas City and
Cincinnati, air  quality impacts were measured using alternative street cleaning
techniques.   In  Kansas  City, data  indicated  that air quality  improved 8 to 18
ug/m3 with flushing,  whereas broom cleaning  showed no improvement
                                     5-13

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For Cincinnati,  the air quality impacts  from flushing and broom sweeping
showed the reverse from that in Kansas City.  Also,  in Cincinnati  where
vacuum sweeping  was tested,  it was not  shovn to be effective in reducing
particulate concentrations.   This finding was unexpected considering the
demonstrated efficiency of the vacuum units in removing small  size parti-
cles from street surfaces and their overall street cleaning efficiency.
These cleaning efficiencies  were determined from street loading measure-
ments taken before and after each cleaning operation.
     Also, in the REDCo study, particulate air quality were obtained or
results were summarized from studies In  five cities in which potential
control measures had been implemented (i.e., some type of street cleaning
program).  Tht.,e cities or studies are:  New York - New Jersey; Kansas City,
Kansas; Charlotte, North Carolina; Chicago, Illinois; and Twin Falls,
Idaho,  The air quality data was reviewed to determine whether the programs
had a discernible effect on particulate concentrations.  The findings were
inconclusive with regard to the effectiveness of improved street cleaning
as shown in Table 5-5.
                               Table 5-5
       Cleaning method
       Broom sweeping
       Vacuum sweeping
       Regenerative air sweeping
       Flushing
       Sweeping and flushing
 Studies 1n
which method
was effective
     1
     0
     0
     2
     0
  Studies in
 which method
was ineffective
       2
       2
       1
       2
       1
                                   5-14

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     Intuitively,  street cleaning as a  control  measure  should  reduce
re-entrained dust, but is still  unproven as  an  effective  method  for
reducing ambient TSP concentrations, therefore, caution is advised in
undertaking control  programs involving  street cleaning.  It is entire-
ly possible that changes in operating procedures (e.g., more frequent,
better operator training) or better designed equipment  with environ-
mental concern in mind or other  improvements in street  cleaning  methods
would reduce ambient concentrations.  However,  prior to any full scale
modification of a city's street  cleaning program, a pilot study in-
corporating a sweeping project is recommended at least  until more data
on the effectiveness of improved street cleaning methods  become avail-
able.  The interest and support  of the public works department are
necessary in order for the measure to be successful.  If  the changes
are not supported or measured as important,  an  expanded or improved
cleaning program will probably not translate into an air  quality improve-
ment.
     Another reason for testing  street cleaning modifications on a smal-
ler scale is that study data from one city may not be applicable in a-
nother due to great difference in street systems (storm drainage, curbs
and gutters, age and type of surface, etc.)  and capabilities of street
departments.*
 Refer to EPA-907/9-77-007 document, Control of Re-entrained Dust From
 Paved Streets for more detailed information on street cleaning, con-
 struction site control, and associated cost.  Additional  guidance is
 currently being prepared for pilot street cleaning studies.  This is
 expected by November, 1977.
                                5-15

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5.3  CONTROL OF DUST EMISSIONS FROM CONSTRUCTION AND DEMOLITION ACTIVITIES
     Construction activities are temporary and variable in nature.  Fugitive
dust is emitted both during the activities (e.y., excavation, vehicle opera-
tion, equipment operations) and as a result of wind erosion over the
exposed earth surfaces.   Earth moving activities comprise the major source
of construction dust emissions, but traffic and general disturbance of
the soil also generate significant dust emissions.

     Wetting the surfaces of unpaved access trails for construction
vehicles and trucks is an effective control for dust emissions provided the
surface is ma..itained wet.  In arid regions this generally requires an
appreciable amount of water.  A study on the effect of watering on construction
sites indicates that extensive wetting of the soil may reduce emissions
from existing construction operations" Up to 60 to 70 percent   • The
study suggested that wetting of access roads twice a day with an application
of  .5 gal of water per square yard will suppress dust emissions from
existing baseline construction practices by 50 percent.  It was assumed
that a certain degree of dust control is currently achieved at most construc-
tion sites, due to typical local regulations requiring reasonable precautions
be exercised in these dust emissions.
     A negative tradeoff associated with watering controls at construction sites
concerns the carryout of mud onto adjacent streets.  The carried out mud later
becomes dust again and is susceptible to suspension by passing vehicles.  If the
construction site is frequented by an appreciable amount of traffic and watering
controls are amply employed, mud carryout will be significant and should be con-
trolled,  A practical means of removing the mud is cleaning the streets in the
vicinity of the construction site.  Cleaning could be employed daily to clean
those paved roads within the proximity of the site and which are used by vehicles
                                    5-16

-------
  1
  I
  1
            exiting off the site.   The  sweeping  program could  be  conducted  in  cooperation

            with the City Maintenance Department.   It  is not possible  to  generalize  an

            effectiveness for this  action.
                 An additional  dust source  at  construction  sites  consists of exposed
            earth which is susceptible to  wind  erosion,  and  to  dust  emissions  from infre-

•          quent traffic disturbance.   While the  suspended  dust  from  this  source  is

            generally insignificant, there are  brief periods (i.e.,  during  wind gusts or

•          traffic bursts) when the resulting  dust  levels may  create  a  nuisance to

            nearby inhabitants.   Dust emissions from these sources may be reduced  by

            combining two control  actions.   First, a soil  stabilizer,  such  as  a chemical

            palliative or vegetation cover may  be  applied.   A second control action would

            involve a stipulation  that cleared  earth be  exposed for  a  limited  period

            before subsequent operations on this land commence.   This  would prevent the

            frequent practice of clearance of vast plots of  land  where subsequent  construc-

            tion operations are  not scheduled to begin for several months.   Clearance

            would be permitted only if accompanied by soil stabilization measures  within

            a  certain period of  the clearing.   The method is quite effective in minimizing

            the  wind erosion impact of construction  activities.   However, there is little

            definite information to quantify the impact  from an overall  % control  effi-

            ciency.   However, one  can apply the wind erosion equation  to the conditions
 I

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                  Cost estimates of the alternative dust control measures for construction
 •          site emissions in the Phoenix area are shown in Table  5-6  for  illustrative
             purposes.  These control costs will vary from region-to-region due to differ-
 9          ences in water availability, street sweeping costs, and cost of dust pallia-
 ^          tives and their application.  A region-specific study is needed to determine
             the actual cost of the candidate measures in the region targeted for controls.

 I
            before and after control  and  obtain  the % reduction  in  suspended  soil.   This
                                              15
            technique is outlined in  Reference
                                             5-17
I

-------
     Dust emissions at demolition  sites derive from essentially the same
source as those found on construction sites.   These sources  involve earth-
moving activities, and general  disturbance of the soil.   The control  methods
available for these sources are the same as that employed at construction
sites (e.g., wetting of access  roads).   A significant portion of dust associ-
ated with demolition activities may also be generated by falling walls, and
an additional significant emission hazard concerns the release of asbestos
particles when demolition involves friable asbestos materials.  The latter
hazard has resulted in the promulgation of demolition and renovation
         49
standards   for institutional,  industrial, and commercial buildings con-
taining a specified amount of friable asbestos materials.  These standards
require that asbestos materials must be removed prior to wrecking activities
by specified handling procedures,  and that these materials be wetted prior
to removal and handling.  The dust created by falling walls of brick, plaster
or concrete may be mitigated by spraying walls with water before teardown
and  immediately after the fall.  This control method may reduce emissions from
                               50
masonry demolition by 10 to 20%  .
                                  5-18

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5.4  CONTROLS FOR AGRICULTURAL  DUST  EMISSIONS
       Techniques for controlling  fugitive  dust  from  agricultural areas
include:
       1.   Continuous cropping  with  limited field exposure
       2.   Crop residue management and modified  tilling  operations
       3.   Limited Irrigation of fallow fields
       4.   Windbreaks and stripcropping
       5.   Chemical  soil stabilizers
       The effectiveness of each of the alternative control  technqiues
can be determined by computing  the influence of each control  on the
wind erosion equation (E = AIKCL'V).   Continuous cropping,  crop
residue and stubble, and stripcropping will effect the vegetative factor
( V) of the equation; some aspects of modified tilling  will  affect the
roughness factor (K) and the climatic factor (C); windbreaks will
effect the unsheltered field length factor ( L'); and chemical soil
                                         15, 17
stabilizers will affect soil credibility
5.4.1  Continuous Cropping
       This technique, which attains maximum productivity from a cropland,
is one which also  lessens the  length  of the period of barren  field exposure
to wind erosion.  Continuous cropping may be accomplished by repeated
plantings of a  single  specific crop, or may involve a complex process of
rotating various crop  types on a given  field throughout the year.  Some
of the Important  factors  which Influence the fanners  decision to plant a
 certain type of crop within  this  rotational scheme are  season, water
demand, water  availability, market  demand, and  the length of  time  that is
required  for the duration of the  crop.   The key limiting factors to
continuous  cropping are the  lack  of rainfall  and regulated water al-
locations  to farmlands.
                                  5-20

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       In many agricultural  areas,  there are  periods  when  fields  are  fallow
while preparations are being made for the next crop as  well  as periods
where fields are barren while in the seedling stage.   For  example,
consider the crops of cotton and sorghum.  Assuming that the non-growing,
residue period for cotton is three months, and that during this time  an
alternate crop is planted (such as a fast growing grain which takes about
a month to cover the ground, enough to eliminate wind erosion) the  annual
fugitive emissions off the cotton field that  would otherwise lie fallow
for three months could be reduced about 67 percent.   For sorghum, the
non-growing residue period is November to July.  Planting  of wheat  after
sorghum harvest in December would leave the sorghum field  in residue
for only one month, resulting in a 78 percent reduction in annual
emissions on fields previously growing only a sorghum crop.
       Cost of continuous cropping measures depend on numerous factors
such as water availability, additional manpower and  equipment requirements,
crop resource requirements, and crop market value.
5.4.2    Crop Residue and Modified Tilling Operations
       Protection from wind erosion can often be provided  by leaving  the
residue or standing stubble of a crop after it has been harvested.  The
quantity and quality of stubble mulch which is required to prevent soil
blowing varies by crop type, soil characteristics, climate, and whether
the residue is standing or flattened.  For instance,  in a semi-arid area,
on a silt loam soil with 25 percent non-erodible fractions, 750 Ibs.
per acre of one foot standing wheat stubble or 1500 Ibs. per acre of one
foot flattened wheat residue is required for complete protection against
soil erosion, while on a loamy sand, 1750 Ibs. per acre of 12" standing
stubble or 3500 Ibs per acre of 12" flattened residue is required,
and, if sorghum is used instead of wheat,  twice the  weight of sorghum
                                 5-21

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           $2
is required  .  Fine residues provide better protection than
short crop residues.  Modifying tilling and plowing operations to
create the most dust free condition on a given field is a complex
issue which depends on the type of crop being Harvested, the next
crop to be planted, the period between crops, and the manpower, equipment,
and time requirements of the farmer.
       The length of time that the standing residue of wheat and barley 1s
left unaltered on fields 1s generally not regulated.  Normally, the
farmer turns residue under when 1t is convenient.  This might happen
very soon before the next planting or as much as a month before the next
planting.  If tilling 1s postponed until just before it is necessary
to prepare the field for the next crop, wind-blown emissions are reduced
by the fraction of  total soil exposure time saved by the postponement.
The potential emissions reductions  w,h1ch can be achieved for an agri-
cultural region 1s  difficult to determine because the exact chronology
of the various farmer's activities  are not generally known.
       No-tillage  farming  1s currently being  used as an advanced farming
method to  prevent  soil erosion, Increase cropland production, and  to
                      53
reduce farming costs    .   Despite  the economic  benefits of  no-till age
farming,  there 1s  substantial  resistance by  farmers  to  depart from
accepted  practice.   If  tilling remains  the accepted  practice  for crop
field preparations, and  1s delayed so that the  residue  can  continue to
provide  soil  erosion  control  as long  as  possible,  significant additional
expense  will  result from additional manpower and equipment  required to
carry out tilling  operations 1n a  shorter  period of time.
                                  5-22

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               Stripcropping consists of the  inter-row planting of erosion-resistant
          crops on  fields with other crops which are erosion-susceptible.   Small grains
          which are closely seeded and  cover  the ground rapidly are  erosion-resistant.
ฃ        Cotton, sugar  beets, peas, beans, and true' crops are generally  erosion-
_        susceptible.   The cost of grain Stripcropping varies with  the  grain  type
"        and  the requirements of that  grain  and also according to the requirements
•        of the erosion-susceptible crop which is  being protected.  Modifications
          in machinery may have to be made in order to tend the crop requirements of
I
I
I
a double-cropped field.
     Stripcropping may be employed most effectively during the early months
of a crop development before foliage 1s sufficient to provide soil erosion
protection,  "owever, the degree of protection provided by this method
would be minimal.  As the main crop begins to develop, the reduction of soil
erosion caused by the accompanying Irrigation itself would probably exceed
          the dust control  benefits  gained  through Stripcropping.
|        5.4.5  Chemical  Soil  Stabilizers
               While a field is 1n the seedling stage or  is  barren,  wind erosion can
ป        be reduced considerably with chemical stabilization.   Investigation  has shown
m        that the liquid,  petroleum res1n-in-water emulsion,  1s the most effective,
          durable, and economical of the many available varieties of stabilizers for
1        this purpose.   Use of herbicides  1s also required  as  the stabilizers provide
          surface layer protection only, and normal weed  removal practices would disturb
I        the protective layer   •
               Documentation of the  effectiveness of the  stabilizers in reducing dust
•        emissions is presently limited.   Based on a recent study of soil stabilizers
                                                                        42
•        conducted by the State of  Arizona Department of Transportation  , the
*        wind-blown dust emissions  from agricultural lands  can be reduced by  about
          f90% provided the surface layer remains undisturbed.   Cost of applying the
                                                                     15
          various stabilizers varies from about $100 to $650 per acre
I
                                   5-24

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5.4.3    Limited Irrigation of Fallow Fields
       The periodic irrigation of a barren  field  will  provide  control  of
blowing soil  by increasing soil  moisture and  crusting  the soil  surface.
The impact of irrigation on dust emissions  may be estimated by determining
the change in climatic factor (C) and soil  credibility (I) due to
additional surface crusting.   The amount of water and  the frequency
of each irrigation during fallow to maintain  a desired level  of control
would be a function of the season and of the  crusting  ability of the
soil.  The main drawback to irrigation control concerns availability of
water, cost of water, and interference with farming activities on the
cropland
5.4.4    Windbreaks and Stripcropping
       Both windbreaks and Stripcropping are  intended to reduce wind erosion
by reducing the wind velocity over barren soil.  The most effective
results are obtained when planting (or placement of physical barriers)
is done perpendicular to the prevailing wind  direction.  Windbreaks
occur around the field, while Stripcropping occurs within the field.
       A windbreak provides lateral wind erosion control equal to ten
                         52
times the barrier height   .   A  barrier  25  feet in  height will control
erosion over 250 feet.  Therefore, on a typical  2000 foot long field,
erosion can theoretically  be  reduced by about 12 percent.  The most
severe drawback of windbreaks for  erosion  control  is their very  high
cost.  Large scale application  of  windbreaks  for erosion control  is
generally considered  unfeasible, particularly in arid  areas where
water availability  is limited.
                                   5-23

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             Table 5-7  summarizes the range of effectiveness and cost of various control
I
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                                        15
measures for agricultural dust emissions
             5.5  Control of Tailing Piles
                  Control methods for fugitive dust emissions from mineral waste heaps
|           include: (1) physical control; (2) chemical binding; and, (3) vegetative
             cover.  The applicability and cost of these controls varies depending on
•           the type of mineral waste and the region in which it is located. Also,
—           applicability varies with other environmental control objectives, such as
"           aesthetics, water pollution control, land use, etc.
•                Physical stabilization of tailings with a cover rock or smelter slag
             can provide complete control of wigd-blown emissions.  A mixture of soil
-                                             I
•           and rock available from adjacent  lands is a more widely used cover material.
             Soil cover  is subject to wind erosion to a lesser degree than the tailings,
|ง           and permits a habitat for encroachment of local vegetation.  The degree of
 —           control provided by the soil cover  is determined by the difference in erodi-
*           bility  of the soil and the more erodible tailings fines.  The primary draw-
 •           back to physical covers as erosion^controls  1s the high cost of application,
             particularly when the cover materials are unavailable  in the"immediate area.
     Chemical stabilizers are commercially available and have been employed
                         15
in numerous applications    to create a crusted erosion-resistant layer on
mineral waste piles.  In applications where the tailings surface is not sub-
ject to disturbance, stabilization by crusting attains a control efficiency
of about 80%  .  Since chemical layers create only a thin skin of protec-
tion,  they offer only temporary protection, and repeated applications are
required periodically to maintain the crust.  Chemical stabilizers are typi-
                          V
cally  used in combination with vegetation to form long-term erosion-resistant
surfaces over tailings piles.  The chemicals promote vegetation growth and
protect seeds during the germination period.  The effectiveness of the vege-
tation in reducing  fugitive dust emissions depends on the density and nature

                                  5-25

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I          o! '.he growth.  In arotis, anrl for tailings piles which will  support heavy
            vegetation, wind erosion dust emissions may be virtually eliminated.   However,
             in areas  less hospitable to plant growth, such as the arid southwest, only
•           native species may be grown (sagebrush,  Indian rice grass, sand dropseed).
             Assuming  a moderate vegetation rate of 500 Ibs/acre v/as attained, fugitive
I           dust  emissions from the tailing piles would be reduced approximately 25%.
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                                54
             (see Section  3.2.2)   .
                 Table  5-8  summarizes the range of effectiveness and cost of the control
             measures  to reduce  tailing pile emissions.
             5.6   Control  of  Unpaved Parking Lots and Truck Stops
•                The  alternative  controls for mitigating dust emissions from unpaved
             parking lots  are the  same as those which may be applied for unpaved roads
|           (see  Section  5.1).  The traffic surface may be improved by paving, gravel -
—           ing,  or applying a  dust palliative.  Table 5-9  lists the efficiency and cost
™           of controls for  parking lot dust emissions.  Since no data are available to
•           characterize  the effectiveness of the measures specifically for parking lots,
             the figures of Table  5-9 are based on the assumption the measures are
             equally  effective  for  parking lots as for unpaved  roads. The cost data are
             the  same as  cost for applications for road  surfacing  discussed  earlier.   Actual
             costs may vary  significantly from region-to-region, and  should  be determined
             specifically by inquiry with local transportation  departments.
_
             5.7   Control  of Emissions from  Disturbed  Soil  Surfaces
•                Feasible control methods to  reduce wind-blown  dust emissions  from  disturbed
             soil  surfaces are  similar to those  described  for  tailings  piles  (Section  5.5)
(           and  unpaved  parking  lots  (Section 5.6).   Control  measures  include  chemical
—           stabilization, vegetation,  and  physical covers.   For  those soil  surfaces  which
™           receive  periodic traffic, such  as residence yards,  playgrounds,  and  some  vacant
A           lots, application  of chemical stabilizers must be intensified  similar  to  that
             required for control  of unpaved road  surfaces.   Soil  covers such as  gravel  may
                                               5-27

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5-29

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provide varying levels of dust protection depending on the application density.
For soil surfaces frequented by minimal  traffic,  combined vegetation and chemi-
cal stabilization generally provide the  most cost effective control, particu-
larly in areas where rainfall is sufficient to support vegetation.
                                    5-30

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I          6.0  INTEGRATION OF FUGITIVE DUST SOURCE IMPACTS
                 INTO THE STATE IMPLEMENTATION PLANNING PROCESS
"          6.1  INTRODUCTION
•               While considerable progress has been made in reducing ambient TSP concen-
            trations in many locations, it is apparent that the primary National Ambient
•          Air Quality Standards (NAAQS) for TSP will not be attained on a nationwide
            basis under the existing State Implementation Plans (SIPs).  In light of this,
|          States are required by Section 172 of the Clean Air Act of 1977 to submit
            Implementation Plans by January 1, 1979 to attain the NAAQS for TSP as expedi-
•          tiously as practical, but no later than December 31, 1982.  As part of this
•          revision process, the States must seriously evaluate the impact of all parti-
            culate matter sources, including fugitive dust sources, and provide a revised
•          SIP to include its control within areas of non-attainment.  If needed,
            strategies for fugitive dust should be developed as a minimum for those areas
jp          where the impact of these sources (by themselves or in combination with other
            particulate matter sources) causes a significant impact upon the health and
™          welfare of the general population.  An overall comprehensive control program
m          for fugitive dust may not be realistic for all areas of the country, especially
            for those areas where natural sources, independent of man's activity are the
8          predominate influencing factors (i.e., isolated rural areas).
                 All strategies developed with areas significantly impacted by fugitive
J          dust sources should reflect the application of needed reasonable control
            measures to those fugitive dust sources which are ttoe major contributors to
•          the fugitive dust problem.  Such control measures should provide for control
•          of fugitive dust sources as expeditiously as practicable.
            6.2  EVALUATION OF CONTROL STRATEGY
tt          6.2.1  Impact of Control Strategy on Emission Levels
                   The emission levels that will result after various control strategy
•          measures are implemented should be estimated for both the target years of
I
6-1

-------
 attainment  and  projected years, considering growth of new emission sources.
 Control  efficiency  information for various fugitive dust control measures,
 (provided  in  Section  5)  in addition  to baseline and projected emissions inven-
 tories,  provide the data base needed for these estimations.  The estimated
 emissions  that  will result after control regulations are adopted and  imple-
 mented should be spatially resolved  to the same level of detail as the base-
 line inventory.   In making such an analysis, a judgment must be made  as to
 emission reduction  impact that will  result for compliance with existing emis-
 sion control  regulations  (e.g., stationary source as well as fugitive dust
 control  regulations).   If the existing regulations are determined  to  be inade-
 quate for the attainment of  the NAAQS, additional emission  control measures
 will be needed.
          Once a list  of candidate measures has been  identified,  selection of
 a control  strategy 1s an  iterative process accomplished  by  means of  successive
.tests of alternatives usingซ;a  source-receptor model  to predict  resulting  air
 quality levels  (see Section  4.3.2).   Through a series of iterative trial
 judgments, a strategy should be established which attains  the  air  quality
 standard utilizing the most  cost  effective combination of control  measures
 available.   The impact of controls  for individual major  source  categories
 should also be  investigated  as an  aid in determining a  reasonable  mix of  the
 various controls for the overall  attainment  objective.
          The control  strategy should be  selective  for the major sources affect-
 Ing air quality.  The strategy may be widespread and/or site-specific depending
 on  the distribution of the major sources causing high TSP levels.   An overall
 areawlde strategy  should be proposed to deal  with the areawide TSP problem
 Insuring attainment of air quality  standards at  all  points within the area of
 concern.  As various trial  alternative strategies are tested, it should become
 clear which  areas  in the study region may need local controls.   For  example,
 certain controls (such as street sweeping)  are more effective within the center
                                     6-2

-------
 I
              cable.  An adequate documentation of the analysis should be prepared for future
              reference.
             city commercial areas, while others (e.g., road paving) are more effective in
 m          outlining suburban areas which are still developing.
                      The overall control strategy developed for fugitive dust sources
 fl          should reflect the degree of control necessary to attain the NAAQS from both
             the short-term and annual average aspects.  In most cases, the long-term area-
 •          wide impact will be the binding constraint; however, in some cases, the short-
             term or localized impact could be of some significance and it should be evaluated.
 •          Once the strategy is finalized, enforceable regulations and compliance test
 M          methods must be developed to implement the strategy.  The final control strategy
             should provide for control of fugitive dust sources as expeditiously as practi-

 I

 I
             6.2.2   Cost of Strategy
 •                  The cost of implementing the control measures will vary widely from
             urban area to urban area.  Local cost data should be obtained from those who
 •          will be responsible for implementing the measures under consideration.  The
 g          total cost of instituting the control strategy should be expressed in terms
             of cost effectiveness and compared to other measures currently being enforced
 •           by existing regulations.  Control strategy cost should also be compared to
             overall city and department budgets to assess the economic significance of the
 •           proposed measures in comparison to existing expenditures and planned rates of
             increase.
 •                   An important aspect in assessing the cost of the controls concerns the
 •|           time frame outlined for implementation.  A control  plan should examine the
 ~           schedule for implementation to determine if significant cost impacts can be
•           minimized by extending the time frame a year or two to ease the economic burden
             and allow for a more realistic program that can be  implemented to demonstrate
I           marked improvements in air quality.
I
                                                  6-3

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6.3  GUIDES FOR THE SELECTION OF REASONABLE CONTROL MEASURES
     Reasonably available control technology (RACT) defines the lowest
emission limit that a particular source is capable of meeting by the
application of control technology that is reasonably available considering
technological and economic feasibility.  RACT for source categories with
somewhat undefined emission points may represent relatively stringent
requirements which in many situations force the application of measures
not previously adopted or implemented in a given area.  The technological
and economic feasibility of various controls will differ depending on
several factors indigenous to the area under consideration.  General factors
affecting ',,'ie reasonableness of a control measure, and which may vary from
area-to-area include:
     o  The compatibility of the controls with the overall goals and plans
        for the area
     o  The timetable for Implementation
     o  The degree of control required
     o  The financing mechanisms available for implementation
     The extent to which the proposed control measures are compatible with
planned development  affects the  cost and  technological feasibility  of the
measure.  For example, the paving of roads for dust  control  is  entirely
compatible with long-term city  development objectives  to  improve  the transpor-
tation  network.   Similarly,  the  Improvement  of road  shoulders  to  reduce
street  dust  loadings and re-entra1nment  of this  dust to the  ambient air  is
completely consistent with city objectives  to  improve the quality of  life in
 the city.  This compatibility  lends  to greater general  technical  and  economic
 feasibility  for  the  dust  control measures because of the  other desirable
 benefits  they provide.
                                      6-4

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 I
 •
                  Another  consideration  in  the  determination of reasonable measures
             involves  the  degree  of control which  is sought.  The ultimate goal of a
0           reasonable  control strategy is the achievement of  the  national  ambient
^           air quality standards.  The higher the level of control needed  for attain-
™           ment,  the greater  is  the  potential  for technical and economic demands to
•           be the binding  constraint when considering a control strategy to attain
             the NAAQS.
•                The  economic  feasibility  of any  control alternative is greatly affected
             by the extent and  manner  of funding available.  Cost required for implemen-
g           tation of different  controls can be compared and expressed in terms of
             the impact  per  capita.  The source and ease of  funding should be identified
9           and evaluated.   Some controls  (such as street  sweeping, road surfacing) will
•           be funded by  taxes or other governmental money-raising mechanisms, while
             others will be  paid  by commercial  enterprises.
•                It is  clear that social acceptance is important to the success of the
             implementation  of  a  control strategy.  Consequently, steps should be taken
|           where appropriate  to determine the social  acceptability of the  measures under
_           consideration.   A  demonstration project, as part of the first phase of imple-
9           mentation,  may  be  used to generate public support when necessary.  The elements
•           of the demonstration project,  and  its implications for resolving implementa-
             tion difficulties, are considered  in  Section 6.4.
I                A measure  which is reasonable in one area may be unreasonable in another.
             In general, most of  the measures for  control of fugitive dust are reasonable
|           with a few  exceptions, the  major one  being the widespread  application of
             chemical  stabilizers to agricultural  lands.  While this method  does have
•           application on  a limited  basis for dealing with short-term construction
             projects, its overall environmental impacts are questionable  if used without
I
I
                                                   6-5

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care.   This measure may have certain  multi-media  impacts which  have  not
been fully evaluated to date which may make  its widespread application
nationwide for agricultural  areas unreasor.ible.   However, for  the most  part,
fugitive dust control  measures are reasonable  from a  technical  point of
view.   Selection, therefore, involves a determination of  the most cost  effec-
tive measures which will provide the  air quality  improvements  needed for
standards attainment.   The timing for the application of  control  measures
is also an important factor when considering the  economic feasibility
of a certain measure.   For example, it may be necessary to  pave a large
number of unpaved roads to bring about attainment, with any lesser degree
being inadequate.  However, this may be unreasonable  from an  economic,
standpoint unless this paving program is done in  phases over the next couple
of years.  Thus, timing, economics and technical  feasibility must be examined
in order to develop the types of controls necessary to provide an overall
comprehensive achievable strategy.
6.4  IMPLEHENTATION ASPECTS
     The  difficulty 1n  Implementing  the  strategy  depends on technical,
political,  legal,  and  socloeconomic  considerations associated with  the  various
control measures.   The magnitude of  these considerations depends  on  the
general  Implementation approach of the strategy,  that  is, whether it is  to
be  enforced as  a series of  air  pollution control  regulations,  or  as  in-line
actions  to be taken by various  agencies  in  the performance of  related projects.
The direct regulatory approach  1s certainly required for several  of the
 source categories. This will be the only sure way to  insure  compliance for
 a number of sources.   However,  in some cases  the direct  regulatory  approach
 may pose some difficulties  and  in fact may  be less desirable  than binding
 agreements on the part of certain departments (i.e., public works,  etc.) that
 they will participate in and be responsible for  the  implementation  of  a cer-
 tain portion of the strategy.
                                        6-6

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                 This "so-called" alternative to the strict regulatory mechanism is an
•          app.-oach which provides for integration (where possible) of the control
            measures into the on-line operations of various governmental agencies.
W          This approach generates greater political and social acceptance in that
•j          these measures are viewed not only as air pollution controls, but as overall
            planning and developmental improvements which will yield several tangible
I          benefits in addition  to air quality improvement.  In view of the types of
            major fugitive dust emission sources which are typically uncontrolled at
I          present, the integral planning approach is particularly appropriate.  Reason-
            ably available controls for unpaved road dust and entrained street dust
•          emissions are entirely consistent with  objectives of the local  transportation
I            and street maintenance departments and  sbould be Incorporated into the overall
            goals and objectives  of these departments.
•               An  example  of this inter-governmental cooperation  and  implementation
            is  found in the  current 208 Vffcter Planning process.  At the present time,
|          208 Water Planning agencies are considering various techniques  to minimize
_          water runnoff from "non-point sources"  which are similar in many cases to
•          fugitive dust sources.  Coordination of air management  planners with water
•          planners may be  mutually beneficial and is certainly encouraged, where
            appropriate.
•               The major obstacle confronting implementation of a fugitive dust  control
            strategy, whether utilizing the integral planning approach or the direct
gj          regulatory technique, concerns the sodฉeconomic acceptability  of the  proposed
_          actions.  Appropriations for some major measures by the respective local agencies
•          require  financial support of the citizenry, whether by  taxes, bonds, or
•          assessment districts.  While the funding needed to support  implementation
            of  the strategy  1s generally relatively minimal, there  is little chance that
I

I

I

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the additional  expenditures associated with the strategy would  be absorbed
in the annual  budgets without clear justification.   Such justification  may
be facilitated by phasing in the controls  with the  implementation of a
demonstration project as the first phase to validate the benefits of the
proposed strategy.
     Implementation difficulties anticipated for each of the control measures
comprising the strategy should be assessed and ranked to establish the
feasibility of successful execution of the proposed program.  The assessment
should consider the approach in which various departments within the govern-
mental structure of the political jurisdiction are  active participants  in
carrying out the strategy.  The assessment may be carried out with or without
the benefit of L demonstration project as the first phase of implementing
the areawlvia strategy.  Such evaluations are necessarily somewhat speculative,
but should be consistent with the economic and technical characterization
of the strategy.  Overall support for these measures should be generated by
providing the overall benefits and objectives of an integrated program to
control fugitive dust.
6.4.1  Demonstration Project
     In some areas where control may meet with significant  implementation
obstacles, demonstration projects may be planned as an integral part of
the control strategy to  generate support and coordinate efforts within various
departments.  Because the impact of fugitive dust sources istjjj^ically very
localized, a control demonstration project  is particularly  appropriate to
insure an achievable program  in a  timely manner.  A demonstration strategy
is useful in a  number of ways.   First,  the  demonstration can be  instrumental
in generating support for a more rapid  implementation of the total  strategy.
Second, the demonstration would  enlist  and  promote  coordination  between
                                  6-8

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I
I
           agencies  to achieve  the overall objectives in a more complete and compre-
           hensive way.  Finally, the demonstration project might be essential as a
           tool  for  further pollution control analysis as it will yield useful insights
•         for appropriate adjustments of the regionwide strategy over time.  To attain
           these  objectives,  the demonstration project should consist of the following
|         elements:
ซ               o Surveys to establish understanding of the overall goals of the
                   long-range plan for the area under consideration.
•               o A cooperative task force committee comprised of representatives from
                   the major  affected departments.  The committee would be responsible
•                 for the planning of the strategy and carrying out phase one or the
_                 demonstration phase.
™               o A field test to demonstrate the effect of the proposed control
•                 measures in  a limited area.  This test would include institution of
                   all controls proposed for the)areawide strateay.  A comprehensive
•                 TSP field monitoring program would be implemented.
                o An economic  analysis to evaluate the cost benefits of the proposed
I                 control strategy.
•              o A public relations program to promote awareness of the benefits
                   of the proposed control plan and to generate support for further
I                 funding to implement the measures on a more accelerated scale.
                The  selection of the specific area for the demonstration would be depend-
|         ent on several factors.  First, receptibility of the various departments and
ฃ         agencies  to participate in the overall program should be assured.  Second,
           the area  should be representative of major emission sources causlnguhigh
I         levels of TSP throughout the problem area.  Third, it would be preferable if
           the selected area  included a monitor of the existing air sampling network.
I
 I
                                               6-9

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This would facilitate the comparison between before and after control  and
would place the test program within the context of the data base used to
develop the strategy.  Fourth, since a key to the utility of the project
is  its effect on social acceptance, the area selection should reflect a
level of social acceptance typical of the characteristic of the entire
region which will eventually be affected by the plan.  Another, but not neces-
sarily final, consideration in area selection is the planned development for
the area.  Desirability for selection of the area is increased when scheduled
development is compatible with the specific controls comprising the demon-
stration project under consideration.
6/5  CONCLUSION
     Statwj eปre  encouraged to  develep  comprehensive  reasonable control  plans
to be implemented as expedHiously as  practicable.   In many areas,  demonstra-
tion projects  will  not be necessary, and the program to control  fugitive
dust can be carried out 1n a much quicker fashion.   In other areas, control
efforts  have already begun, and further complete enforcement of existing
regulations will  go a long way in reducing TSP  levels due to fugitive  dust.
An adequate decumentation of  the analysis of the strategy should be developed
to insure completeness.   Once  the strategy is finalized, enforceable regula-
tions and compliance test methods must be developed  to implement the strategy.
The plan to control particulate matter should be a comprehensive one which
Integrates the control of fugitive dust, stack emissions, industrial process
fugitive particulate emissions and other area sources into a "well-oiled"
program to reduce ambient TSP  concentrations as expeditiously as practicable
striving for overall acceptance, reasonableness and effectiveness.
                                   6-10

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APPENDIX A
        A-l

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           Figure A-l.  Soil •rodibility ซK a tfunetioa of |ปareiciซ stsฎ
M - i '
                                         A-2

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                                              A-3

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Table  A-l.  VALUES OF K. L AND V FOR  OOMMOK FIELD CROPS
                                                        17

Crop
Alfalfa
Barley
Beans
Corn
Cotton
Grain Hays
Oats
Peanuts
Potatoes
Rice
Eye
Safflower
Sorghum
Soybeans
Sugar Beets
Vegetables
Wheat
K
1.0
0.6
0.5
0.6
0.5
0.8
0.8
0.6
0.8
0.8
0.6
1.0
0.5
0.6
0.6
0.6
0.6
L,ft.
1000
2000
1000
2000
2000
2000
2000
1000
1000
1000
2000
2000
2000
2000
1000
500
2000
V,lb/acre
3000
1100
250
500
250
1250
1250
250
400
1000
1250
1500
900
250
100
100
1350
                            A-4

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                A-6

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   Appendix B:  Detailed Description of the Hanna-Gifford Model



     Analytically, this model may be formulated, for cases where emission

strength of the receptor grid is much less than that of the neighboring

grid squares, as follows:
x * (-)
*   vir
1/2
                         1-b
                 u  au-
     N
Qo+  I
    1=1
                                     [(21+1 )]"b -(21-1
                                                                       (B.I)
                                          ~ 1, 2, 3, ...,N
or for uniform emissions from all neighboring grid squares as
     x = C (Q/u)
                                                              (B.2)
where
     Q  =
                                                     •I
     Qo = Source strength for the receptor grid (yg/m /s)
                                                       p
     Q.J = Source strength for the ith grid square (yg/m /s),

      u = Average wind speed (m/s) over the desired averaging time
          (Greater than 20 minutes),
                                                                   o
      x = Average concentration for a suitably defined region (yg/m ),

     AX = Grid width (m),

      N = Number of grids in any one direction that analysis indicates
          may have an impact on the receptor (usually limited to 4).
                                              B-l

-------
The terms a,b are based on the assumption that the vertical dispersion
can be approximated by
        = axb
                                                           3
where the "a" and "b" can be found in the COM User's Guide  .
               Physical removal mechanisms can be incorporated into the
model through the multiplicative factor
     1/0 + C (vd/u))
where v . is the deposition velocity.  As a first approximation to the
deposition velocity, the terminal velocity of the particles may be used,
                                                                    40
The terminal velocity may be found in Meteorology and Atomic Energy   >
if the particle diameter and density are known.
                                  B-2

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             Appendix C:  Modified CDM/Rollback Model

     The analytical formulation of the CDM/Rollback source-receptor
relationship is given by the relation

          Xi = a^C. + a2.E. + B                                 (C.I)

where
     X. = Total suspended particulate concentraton, observed.
     C. = COM calculated concentration of 0-10 and 11-20 ym particles.
     E. = Emissions of particles >20 ym in the grid square of the
          receptor.
      B = Background TSP.
    a-|. = Empirical coefficient to adjust COM air quality predictions.
    a2. = Empirical coefficient relating emissions to air quality
          for large particles.
      i = Denotes the receptor under consideration.
     With the magnitude of the assumed background and the particle
size distribution on the Hi-Vol filters known, it is a simple task to
determine o^ and c^ in the above equation.   For example,
     let F  = Average fraction of particles greater than 20 ym on
              Hi-Vol filter of monitor i (the larger F is, the greater
              is the influence of fugitive sources on TSP.
and let FB  = Average fraction of particles greater than 20 ym on
              Hi-Vol filter of background stations.
     Then it follows that
                                  C-l

-------
            i = a2.  E.  + FgB                                      (C.2)
     and (1-F) X.  = a]1  C1  + (1-Fg)B                              (C.3)


Solving for the empirical  coefficients,


                (1-F) X. - (1-FB)B
          -11
                FX. - FRB
                    -1-.                                        (C.5)
A sample calculation is presented in Appendix E.
                                  C-2

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 I

 I
 •         Appendix D:   Information Required as Input to the CDM/Rollback Model

 •                   The specific format and description of the input procedures
 •         relating to  the source emissions data, meteorological  data and receptor
            locations are well-documented in the COM User's Guide and, hence, are
 I         not reproduced here.   However, for continuity, a brief summary of the
            required input to the model is given.
 I              Meteorology Data
 M              Meteorology data for the study area are obtained from the National
 *         Climatic Center (NCC) in Asheville, North Carolina.  The NCC provides
 I         both the joint frequency function and mixing height data.  The joint
            frequency function is a combined frequency of occurrence for three
 |         meteorological parameters as defined by COM:  six stability classes, six
 m         wind speed classes, and sixteen wind directions.  The annual mixing
 I               5'ฐ
 "         height   and frequency functions should be obtained for the base year of
 •          the study, and an additional distribution should be obtained for a more
            extended period to reflect annual averages.  The annual average will be
 I          used to forecast future air quality.  Note that the COM requires a
 m          division of  D stability into day-night frequencies and that E and F
 •          stability frequencies are combined.
 •               Determination of the Decay Constant
                 The pollutant half-life is required for the estimation of the decay
 I          term used in the COM diffusion model for the 10-20 ym  range.   Half-life
            refers to the time elapsed before the ambient concentration of a given


I

-------
size particulate is reduced by one-half due to physical removal mecha-
nisms (e.g., dry deposition and gravitational settling).  The following
                                                       39
derivation of half-life is based upon the Phoenix study  ; however, the
procedure can be readily applied to other areas.  The computational
technique is based on Van der Hoven's dry deposition formulation.
First, it is assumed that a 15 ym diameter particle is representative of
the 10-20 jam range.  Then for an average wind speed of 2.41 m/s (mean
for Phoenix) and a terminal fall speed of 1.69 cm/s (corresponding to a
15 urn diameter particle), Van der Hoven's expression for reduction of
the source strength due to dry deposition may be used to determine the
distance at which the effective source strength has been reduced to half
its original value due to dry deposition.  The time that it takes a
parcel of air, embedded in the mean flow, to travel that distance may
then be used as the half-life for particles  in the 10-20 ym size range.
An appropriate half-life value may then be used in the exponential decay
term of COM.
     The results of the calculations, using  the technique  outlined
above, are shown in Table D-l.
     Because half-life  (and the resulting decay term  in COM) varies with
both stability and wind speed, the user must decide whether to use
separate values for the various wind speed/stability  categories of
COM or to use a single  composite value.  For Phoenix,  a single composite
value was used on  the basis that this is only an approximation technique
and  that  a more complex analysis is  not justifiable.   The  composite value
was  derived  from a weighted average  of the half-life  times given  in
Table D-l.
                                      D-2

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I

I

•                      Table D-1.   Half Life for Physical  Removal
•                              Mechanism in the COM for a  15ytn
                                Particle and a Mean Wind Speed of 2.4 m/s.
I

I

I

I

I

I

I
•          *Not calculated,  but can graphically be shown to be essentially infinite.
•               The weights  used should be a function of two factors:  (1) the
B          percent frequency of each stability and (2) the relative contribution
•          to the predicted  concentration given by the model for each stability clas:
            The latter contribution to the weighting term can be approximated from
                                                           159
            xu/Q curves (for  example, those given by Turner  ).  Such an analysis
_          for Phoenix,  shows that the weighted average only need  be representative
•                                         "                    39
•          of D, E and F stability.  Sased on that calculation  ,  the suggested
•          decay time is approximately 40 minutes.
Stability
A
B
C
D
E
F
Half Life (min.)
Q&™
QQW
691.2
62.2
42.2
27.7
 I
D-3

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     Emissions Parameters
     Emissions parameters required as inputs by the air quality model
include diurnal assignment of emissions, stack heights of sources, half-
life of pollutant and magnitude of emissions by particle size class and
grid sector.
     The distribution of emissions between day and night is a required
input parameter to COM.  To estimate this distribution, the emissions
patterns of the major sources should be evaluated.
     Physical stack parameters required for model plume rise calculations
may be obtained from the National Emissions Data System.  The source
emission heighc for the area sources must be assumed (10 m was used in
Phoenix).
     Particle size distributions of the various emissions source cate-
gories should be used to express the gridded emission inventory (Section
3) in terms of the three particle size ranges (Section 4.2).  Because of
the general lack of information available to characterize the particle
size of the various sources, substantial uncertainty is associated with
available distribution estimates.  Figures D-l and D-2 summarize the
available data for particle size distributions of anthropogenic fugitive
dust sources and conventional sources.  Distributions for fugitive
emissions caused by wind erosion approximate that of the parent soi-1
(Section 3.2.2), and must be determined from soils data for the specific
study area.
                                    D-4

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I
I                   Appendix  E:   Sample Application  of the  CDM/Rollback Model

•                   This appendix outlines  the procedures which were  used  to adjust the
•             air quality model  estimates  and to  generate  baseline air quality pro-
               jections for future years.
I
                E.I   Determination of Empirical  Coefficients
                          Figure  E-l  is a  schematic  diagram  portraying  a  single  complete
                run of  the CDM/Rollback model.   In the  first step,  the  Emissions Simu-
                lator Program produces a disaggregated  gridded emission inventory.   Next,
                emissions  from 0-10 and 11 -2oiiym ranges  are combined with  the meteorologi-
                                             l
                cal data and  run  through the  C0M,  The  COM output and the emissions in
                                                                         39
          ;      the 21 -7Cin|fli range are input to a  parameterization program."    This  program
 I             requires two  additional inputs:  (1)  the average contribution of  each of two
 !
 •             particle size ranges (0 to 20, and 20-70 pi)  to TSP levels at a given recep-
                tor,  and (2)  the  background level of TSP in  the study area.   The source and
 I             procedure  for tabulating these Inputs,  plus  the actual  assignment of
                empirical  coefficients to  the model, are discussed below.
 I
                     Background  Levels of TSP
 •                  A survey of monitoring  sites located remotely from any urban  area
 •              of the study region should be undertaken to determine typical background
 ™              levels of TSP affecting the  monitor measurements.  The background  level
 I              may  be interpreted as an  uncontrollable source comprised of particulate

 I

 I
                                                E-l
  I

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             Raw Data
            for Emission
            Categories
    Emissions Simulator
(Produce Emissions Grid)
Meteorology Data
                                       Binary Output
                                      of Emissions/grid
                                     for 4 Particle Sizes
                         i
                   Emissions for
                   0-10  ami  11-20
                    micrometer
                       range
                         I
                          COM
                  (Calculate TSP for
                0-10 and 11-20 micro-
                meters).
     Decay Constant
        for 11-20
       Micrometer
          Range
                                        Parametrlzatlon
                                      (Assign Empirical
                                       Coefficients and
                                          Background)
                                          A1r Quality

                                           Estimates
Printed Output
 of Emissions
                               1
                          Emissions for
                              21-70
                           micrometer
                              range
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                       Figure 1:   Computer  Modeling System
                                              E-2

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_         loading and originating from (1) natural sources in the area, and (2)
           from suspended particulates transported from other areas.  Background
                                                               O
           Iparticulate levels typically vary from 20 to 40 yg/m  throughout the
                         15, 60
           United States
I              Partlculate Size Distribution of Ambient TSP
                Mechanical separators (e.g., cascade impactors) or microscopy
•         analyses of hi-vol filters serve as the basis for establishing the
•         average contribution of each particle size class to the TSP levels.  In
           areas with numerous fugitive dust sources, a substantial portion of the
I         particulate mass found in hi-vol monitor filters is comprised of par-
           ticles greater than 20 ym diameters.  Particle size determinations
•         should be obtained for selected days of contrasting meteorology and TSP
•         levels at each of the various monitor sites.  Distinguishable patterns
           in the particle distributions at each of the monitors should be identi-
I         fied, and an average distribution should be estimated over the range of
           meteorology and TSP levels experienced in the baseyear.  In the Phoenix
                              139
           Fugitive Dust Study  , the resulting particle distributions on the hi-
•         vol filters was relatively invariant for the particle classes considered
           in the model parameterization.   Although sampling was limited, the
I         results showed   about 70% of the particle mass to be comprised of
           particles larger than 20 ym at all  monitor sites examined, under both
|         windy and calm conditions.  In the Phoenix study, this finding simpli-
fied the assignment of empirical  constants substantially.
                                  E-3

-------
     Assignment of Empirical  Constants
     Recall that the overall  air quality model is expressed as:

     Xi = ali Ci + a2i Ei + B                                     (CJ)
The empirical coefficients are calculated after the COM has estimated
the ambient level of suspended particulates (C.) in the 0 to 20 pm
diameter size range using Equations (5) and (6).  Table E-l illustrates
a systematic computation scheme for the empirical coefficients for
Phoenix where microscopic analysis gave an F value of 0.7.   Column 1,
2, and 3 contain the COM predictions based on emissions from small
particles, column 4 the actual observed air quality, and column 5 the
emissions of particle 21-70 pm within the grid sque.re of each receptor.
Columns 7 and 9 are the contribution of TSP from particles 0-20 pm in
size and from particles 21-70 pm in size, respectively.  The coeffi-
cients a-|.j and ซ2^ are shown in columns 6 and 8 and are computed from
the equations above.  X. is found  in column 11 and C- and  E. are in
columns 3 and 5, respectively.
     A brief statistical analysis  of the observed and estimated concen-
trations in columns 3 and 4 can give some indication of the performance
of the COM.  Figure E-2 shows the  comparison between the COM model
results (for the 0-20 pm particles) and 30% (recall that the microscopic
analysis of the  Hi-Vol filters indicated that  30% of the weight of the
particulates on  the filter were 20 pm and smaller) of the  observed
                                   E-4

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concentration at each site.  Also shown in Figure E-2 is the result of a
                                                                  o
linear regression analysis of that data.   The intercept (18.6 yg/m )
                                                        3
is very close to value assumed for background, 15.0 yg/m  for the 0-20
ym range.  The slope, 0.51, is a common result for Gaussian models.  A
prior application of COM without modification for particle size (not
shown here), resulted in essentially no correlation between observed
and estimated concentrations.  The regression analysis, therefore, gives
some indication that the modified COM substantially improves the treatment
of 0-20 ym particles.  This is significant since nearly 70% of the emissions
are in this size range (for Phoenix).
     An explanation that completely accounts for differences between the
COM resultfl estimates the observations is not possible, but the following
observations should be considered.  First, there is probable bias of the
observed values from true representative concentrations due to variations
in monitor height, completeness of data, and representativeness of the
monitor site environment.   Second, there is probable bias in the
emissions data base due to numerous uncertainties underlying the develop-
ment of the fugitive dust emissions inventory.  Third, there is the
possibility of an inconsistent assumption regarding the particle size
distribution 1n the emissions data and the monitor data,  Finally, there
are limitations associated with the assumptions of the model Itself.
While the Implications of any one particular limitation on the pre-
dictability achieved by the model may be assessed, the simultaneous
intervention of many influencing factors known to be affecting the model
results make any attempt to explain the variations very difficult.  In
addition, the explanation  is likely to be different for each of the
monitor sites.
                                     E-7

-------
     It must also be recognized that the relationship between local
emissions levels and TSP, as reflected in a2i,  is distinctly unique  for
each grid square because of the numerous variations of local source
distributions around the monitors.   Accordingly, it was considered
appropriate to assign a separate empirical factor for application to
each of the monitor sites.  This, of course, makes the interpretation
and application of this model highly site specific.  It must be kept in
mind that the value of o^ will change according to future development
in the grid square and periodic revaluation is necessary.

     E.2  A1r Quality Estimates
          The base line emissons levels corresponding to the base year and
projected years are translated Into air quality descriptions using the
empirical source receptor relationship discussed previously.  The model
is used to evaluate contributions of each of the source categories to
TSP levels, and the Impact of source changes on air quality.
     Base Year Estimates
     The empirical model  should  be employed to calculate suspended
particulate levels caused by each of the major emission sources sus-
pected to be affecting TSP  levels significantly.   For areas where TSP
levels are dominated by  fugitive dust  sources,  it  is  likely that nearly
all the TSP level  (excluding background) will be caused by  emissions
from unpaved roads, entrained  street dust,  construction activities, or
wind erosion.   Sites which  are most dramatically affected by wind-
erosion emissions  tend  to be located  in  the rural  areas presently under
                                    E-8

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development.  Other sites within cities may also be significantly
affected by wind-blown dust emissions.   These sites are generally
surrounded by numerous vacant lots and/or dirt around residence yards.
Entrained street dust tends to impact air quality at sites located in
the city areas.  Emissions from unpaved roads may contribute signifi-
cantly to TSP at each of the sites, but are generally particularly
dominant 1n the suburbs areas.  Table E-2 illustrates the effect of
these major fugitive dust sources in the Phoenix area, as estimated by
the source-receptor model.
     Projected Base Line TSP Levels
     The projected emission levels for future years should be translated
into air quality estimates using the source-receptor model developed
earlier.  These estimates are compared to base year levels for each of
the monitoring locations In the study area.  Significant changes in air
quality are calculated and analysed.  In many cases, air quality in
areas presently experiencing fugitive dust problems will improve sig-
nificantly  in future years due to base line development planned for the
area.  This development will change the distribution of emission sources,
eliminate local sources near the monitors, and diminish the magnitude of
many sources.  While total dust emissions from unpaved roads may not
decrease, the distribution of these emissions may  change substantially
owing to city roadway  improvement programs.  Wind  erosion emissions may
decrease in future years due  to reduction in wind  erosion sources  (i.e.,
vacant property), and  may  increase or decrease based on expectation of
                                    E-10

-------
typical meteorology in future years.  Contributions to TSP from entrain-
ment of street dust are expected to Increase with increasing vehicle
registration, especially at monitors located within the city areas.
Table E-3 is an example format useful for comparison of the base year and
                       \
projected base line source contributions to air quality.
                                  E-ll

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                                  References


 1.   U.S.  Environmental  Protection Agency,  "An  Implementation  Plan  for Suspended
     Participate Matter  in  the  Phoenix Area"  -  Volume  I, Air Quality Analysis,
     EPA-450/3-77-02U,  1977.

 2.   TRW Systems Group,  1970.   "Air Quality Display  Model".  Prepared for
     National  Air  Pollution Control  Administration under Contract No. PH 22-68-60
     (NTIS PB  189194),  DHEW, U.S.  Public  Health Service, Washington, D.C..

 3.   Busse,  A.  D.  and  J.  R. Zimmerman.   "User's Guide  for  the  Climatological
     Dispersion Model",  Publication No.  EPA-RA-73-024  (NTIS PB 227346/AS),
     U.S.  Environmental  Protection Agency,  Research  Triangle Park,  N.C. 27711,
     December  1973.

 4.   Empirical  Analysis  Toward  Total Suspended  Particulate Source Classification
     in Texas.  University  of Texas at Austin,  Applied Research Lab.
     ARL-TR-76-48.   Page 12, October 1976.

 5.   National  Assessment of the Particulate Problem.  Volume V - Baltimore.
     EPA-450/3-76-026c.   Pages  21-29, June  1976.

 6.   National  Assessment of the Particulate Problem.  Volume XVI -  Providence.
     EPA-450/3-76-026n.   Pages  15-17, June  1976.

 7.   National  Assessment of the Particulate Problem.  Volume I - National
     Assessment.   EPA-450/3-76-024.  Pages  265-323,  July 1976.

 8.   National  Assessment of the Particulate Problem.  Volume II - Particle
     Characterization.   EPA-450/3-76-024.   Pages 1-25, July 1976.

 9.   U.S.  Environmental  Protection Agency,  "An  Implementation  Plan  for Suspended
     Particulate Matter in  the  Phoenix Area"  -  Volume  II,  Emission  Inventory,
     EPA-450/3-77-021b*  1977.

10.   U.S.  Environmental  Protection Agency,  "Guidelines for Air Quality Maintenance
     Planning  and  Analysis", September 1974.

11.   U.S.  Environmental  Protection Agency,  "Guide for  Compiling a Comprehensive
     Emission  Inventory", March 1973.

12.   Communication with Maricopa County  (Arizona) Highway  Department, March  1976.

13.   Midwest Research  Institute, "Quantification of  Dust  Entrainment  from  Paved
     Roadways". Prepared for Environmental  Protection  Agency,  March 1976.

14.   PEDCo Environmental, "Control of Re-entrained Material  from Paved Streets".
     Prepared  for  U.S.  Environmental Protection Agencyป 1977.

15.   Jutze, George and Axetell, Kenneth  - PEDCo Environmental  Specialists,  Inc.,
     Investigation of Fugitive  Dust".  Volume I - Sources, Emissions  and  Control.
     Prepared  for  U.S.  Environmental Protection Agency, June  1974.


                                        F-l

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16.   Phoenix  Newspapers,  Inc.,  "Inside  Phoenix  1976".

17.   Cowherd, Chatten and Axetell ,  Kenneth  •  Midwest  Research  Institute,
     Development of Emission Factors  for Fi"">itive  Dust  Sources",  1976.

18.   Arizona  Crop and Livestock Reporting Service,  "1974  Arizona  Agricultural
     Statistics", Bulletin 5-10, Phoenix, Arizona,  March  1975.

19.   Maricopa County Planning Department, "A  Report Upon  Future General  Land
     Use For  Maricopa County, Arizona", February 1975.

20.   Tonto National Forest Service, Phoenix,  Arizona, personal communication,
     May 1976.

21.   U.S.  Forest Service, Phoenix,  Arizona, personal  communication,  May 1976.

22.   Bureau of Land Management, U.S.  Department of Interior,  personal  communi-
     cation,  ?tey 1976.
23.  Phoenix ("ity Parks and Recreation Department, personal  communication,
     May li/6.

24.  Glendale City Parks and Recreation Department, personal communication,
     May 1976.

25.  PEDCo Environmental, "Nevada Particulate Control Study for Air Quality
     Maintenance Areas, Factors Influencing Emissions from Fugitive Sources".
     Prepared for U.S. Environmental Protection Agency, January 1976.

26.  Roberts, J. W.; Matters, H. A.; Marigold, C. A.; and Rossano, A.T. -
     "Cost and Benefits of Road Dust Control in Seattle's Industrial Valley",
     Journal of the Air Pollution Control Association, September 1975.

27.  Communication with Maricopa County Transportation Department, June 1976.

28.  Hagen, L. J. and N. P. Woodruff, "Particulate Loads Cuased by Wind Erosion
     in the Great Plains".  Presentation at the 66th Annual Meeting of Air
     Pollution Control Association, June 1973.

29.  Culkowski, W. M. and M. R. Patterson, 1976: A Comprehensive Atmospheric
     Transport and Diffusion Model.  ORNL/NSF/EATC-17.

30.  W. F. Hilsmeier and F. A.  Gifford, Jr. - Graphs for Estimating Atmospheric
     Dispersion, 'JSAEC Report ORO-545, Weather Bureau, Oak  Ridge, Tennessee, 1962.

31.  Hosker  (Jr.), R. P., Estimates of Dry Deposition  and Plume Depletion Over
     Forests  and Grassland,  IAEA-SM-181/19, Air  Resources Atmospheric Turbulence
     and Diffusion Laboratory,  November 1973.

32.  G. A. Briggs, Diffusion Estimation for Small  Emissions, U.S. Department of
     Commerce,  NOAA=ERL-ARATDL  contribution no.  79  (Draft), Oak Ridge, Tennessee,
     May 1973.
                                      F-2

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33,   F.  B.  Smith,  "A Scheme for Estimating  the  Vertical  Dispersion  of a  Plume
     from a Source Near Gound Level",  Chapter XVII,  Proceedings  of  the Third
     Meeting of the Panel  on Air Pollution  Modeling, N.A.T.O.  Committee  on  the
     Challenges of Modern  Society,  Paris, France,  October 2-3,  1972, Proceedings
     No.  14, Air Pollution Tech. Information Center, U.S. Environmental
     Protection Agency, Research Triangle Park, North Carolina,   1973.

34.   Briggs, Gary A.    Plume Rise.  USAEC Critical  Review Series  TID-25075,
     National Technical Information Service, Springfield, Virginia. 1969.

35.   Hanna, S. R.  - A Simple Method of Calculating Dispersion  from  Urban Area
     Sources.  J.  Air Poll. Cont. Assoc., Ij2, 774-777 (December 1971).

36.   Gifford, F. A. and S. R. Hanna.  Modeling  Urban Air Pollution. Atmos.
     Environ.. 7., 131-136 (1973).

37.   Hanna, S. R.   A Simple Dispersion Model for the Analysis  of Chemically
     Reactive Pollutants.   Atmos. Environ., 7_,  803-817 (1973).

38.   Nevada Particulate Control Study for Air Quality Maintenance Areas: Task  D/E
     Report, Emission Modeling and  Control  Strategy Development. PEDCo  Environ-
     mental Specialists, Inc., Cincinnati,  Ohio.  Prepared for the  U.S.  Environ-
     mental Protection Agency, Region IX, under Contract No.  68-02-1375, Task
     Order No. 29.  December 1976.

39.   U.S. Environmental Protection  Agency,  "An  Implementation Plan  for Suspended
     Particulate Matter in the Phoenix Area - Volume III, Model  Simulation  of Total
     Suspended Parti cul ate Matter Levels -  EPA-450/3-77-02U,  1977.

40.   Slade, D. H.  (ed.), Meteorology and Atomic Energy 1968,  U.S. Energy Research
     and Development Administration, TID-24190, July 1968.

41.   Dumbauld, R.  K.; J. E. Rafferty; and H.  E. Cramer.   Dispersion-Deposition
     from Aerial Spray Releases. Third Symposium on Atmospheric Turbulence
     Diffusion and A1r Quality, Raleigh, N.C.,  October 1976.

42.   Sultan, Hassen A. (Dr.)   Arizona Transportation and Traffic Institute,
     "Soil  Erosion and Dust Control of Arizona  Highways, Part IV, Final  Report
     Field Testing Program".  Prepared for  Arizona Department of Transportation,
     November 1976.

43.   Communication with Hawkins Company, Phoenix, Arizona, July 1976.

44.   U.S. Environmental Protection  Agency,  "Compilation of Air Pollutant Emission
     Factors", Supplement No. 5. December  1975.

45.   U.S. Environmental Protection  Agency,  "An  Implementation Plan  for Suspended
     Particulate Matter in the Phoenix Area" -  Volume IV, Control Strategy
     Formulation, EPA-450/3-77-021d, 1977.

46.   Dunbar, D. R., "Resuspension of Particulate Matter", Standards Implementa-
     tion Branch, Control Programs  Development Division, U.S. Environemental
     Protection Agency, Research Triangle  Park, North Carolina, March  1976.
                                        F-3

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47.   American Public Works Association,  "Water  Pollution  Aspects  of  Urban  Runoff",
     APWA, Chicago, 1969.

48.   Communication with City Department  of Transportation,  Phoenix,  June  1976.

49.   U.S. Environmental Protection Agency, "Background Information on  National
     Emission Standards for Hazardous Air Pollutants", October 1974.

50.   NATO Committee on the Challenges of Modern Society,  "Air Pollution:   Control
     Techniques for Particulate Air Pollutants".  Prepared  for Environmental
     Protection Agency, October 1973.

51.   Communication with Phoenix Department of Transportation and  Road
     Maintenance, June 1976.

52.   U.S. Department of Agriculture, "How to Control Soil Blowing",  Farmer's
     Bulletin No. 2169, July 1961.

53.   "Farming Without the Plow", The Washington Post, Sunday, January  18, 1976.

54.   Donovan, R. P.; Felder, R. M.; and H. H. Rogers, U.S.  Environmental
     Protection Agency, "Vegetative Stabilization of Mineral Waste Heaps",
     April lb/6.

55.   Dean, K. C. and R. Havens, "Stabilizing Mineral Wastes", Engineering Mining
     Journal. April 1971.

56.   "Chemical Treatment  of Waste Tailings Puts an  End to Dust Storms", Engineer-
     ing  Mining Journal,  April 1971.

57.   Dean, K. C. and R. Havens, "Reclamation of Mineral Milling Waste". Presented
     at Annual AIME Meeting, San  Francisco, California, February 1972.

58.  National Oceanic  and Atmospheric Administration, 1976.  A Climatological
     Analysis of Pasquill Stability  Categories, National Climatic center, Federal
     Building, Asheville, North Carolina  28801.

59.  Turner, D. B., 1970.   Workbook  of Atmospheric  Dispersion Estimates,  PHS
     Publication No. 999-AP-26  (NTIS PB  191482), Office of Technical  Information
     and  Publications,  U.S.  Environmental  Protection  Agency, Research  Triangle
     Park, N.C. 27711.

60.  U.S.  Environmental Protection Agency,  "Guidelines for  Air Quality
     Maintenance  Planning and  Analysis",  September  1974.

 61.   U.S. Environmental Protection  Agency, "Aerosol Sampling and Analysis,
      Phoenix,  Arizona", EPA-600/3-77-015, February  1977.
                                     F-4

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                                    TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
       ^ NO.
           EPA-450/2-77-029
                              2.
                                                             3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
 Guideline for Development of  Control Strategies  in
 Areas in with Fugitive Dust Problems -
IB. REPORT DATE  _
1    October,  i977
6. PERFORMING ORGANIZATION COOE
7. AUTHOR(S)
 George Richard,  TRW
 Dallas Safriet,  EPA
                                                                                           N~0
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 TRW
 Environment  Engineering Division
 One Space  Park
 Redondo Beach,  California
                                                            MO. PROGRAM ELEMENT NO.
 11. CONTRACT/GRANT NO.

!      68-01-3152
12. SPONSORING AGENCY NAME AND ADDRESS
 U.S. Environmental  Protection  Agency
 Office of Air  Quality Planning and Standards
 Monitoring and Data Analysis Division
 Research Triangle Park, North  Carolina 27711
                                                             13. TYPE OF REPORT AND PERIOD COVERED
      Final
 14. SPONSORING AGENCY CODE
      200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
 The document  outlines a methodology for development of control  strategies for  areas

 experiencing  non-attainment problems due to fugitive dust emissions.
                                 KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS jb. IDENTIFIERS/OPEN ENDED TERMS
Participate Matter
Total Suspended Parti cul ate
Emission Sources
Control Methods
Fugitive Dust
Air Quality Measurement
Air Quality Modeling
18. DISTRIBUTION STATEMENT
Release Unlimited

18. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
u. COSATI Fiela/Group ]

21. NO. OF PAGES (
158 I
22. PRICE j
EPA Form 2220-1 (Rev. 4-77)   PREVIOUS EDITION is OBSOLETE
                                               G-l

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