United States
                    Environmental Protection
                    Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711    ''
                    Research and Development
EPA-600/S2-83-110 Jan. 1984
&ER&         Project  Summary

                    Iron  and  Steel  Plant  Open
                    Source  Fugitive  Emission
                    Control  Evaluation
                    Thomas Cuscino, Jr., Gregory E. Muleski, and Chatten Cowherd, Jr.
                      Open dust sources in the iron and
                     steel industry were estimated to emit
                     88,800 tons/year suspended particulate
                     in 1978 based on a 10 plant survey. Of
                     this, 70, 13, and 12% were emitted by
                     vehicular traffic on unpaved roads, vehi-
                     cular traffic on paved roads, and sto-
                     rage pile wind erosion, respectively.
                     Emission measurements, utilizing the
                     exposure profile technique, indicate  a
                     17% solution of a petroleum resin (Co-
                     herex") in water on an unpaved road re-
                     duced  heavy-duty vehicle emissions by
                     95.7% for total particulate, 94.5% for
                     particulate <15 /urn, and 94.1 % for par-
                     ticulate <2.5 /urn  (averaged over the
                     first 48 hours after application). Plain
                     water  reduced emissions 95%  for all
                     particle sizes half an hour after applica-
                     tion. Four hours later, efficiency of wa-
                     tering  had dropped to 55%  (total),
                     49.6%(<15/um),and61.1%«2.5Aim).
                     CoherexR on an unpaved road travelled
                     by light-duty  vehicles reduced emis-
                     sions by 99.5% (total),  98.6%  «15
                     Aim), and 97.4% (<2.5 /mi), 25 hours
                     after application. Control efficiency de-
                     cayed  to 93.7% (total),  91.4%  «15
                     fjm), and 93.7% (<2.5 yum), 51 hours
                     after application.
                      On paved roads, vacuum sweeping
                     reduced emissions 69.8% (total),  50.9%
                     «15 yum), and 49.2% «2.5 yum), 2.8
                     hours after vacuuming. Forty minutes
                     after water flushing, emissions were
                     reduced by 54.1% (total), 48.8% (<15
                     yum), and 68.1%  (<2.5yum). Combined
                     flushing and broom sweeping reduced
                     emissions by 69.3% (total), 78.0% «15
                     fjm), and 71.8% (<2.5/urn), 40 minutes
                     after application.
                      Control  of emissions from coal
                     storage piles varied from 90% to almost
zero depending on the type of treatment,
length of time since treatment was
applied, and windspeed. Tests were
performed using a portable wind tunnel.
  Relationships were developed to
determine relative cost effectiveness of
open source emission controls.
  This Project Summary was developed
by  EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park,  NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project  Report  ordering
information at back).


Introduction
  Previous studies of open dust particulate
emissions from integrated  iron and steel
plants provided strong evidence that open
dust sources  (e.g., vehicular traffic on
unpaved and paved roads, aggregate
material handling, and wind erosion)
should occupy a prime position in control
strategy development. These conclusions
were based on  comparability between
industry-wide uncontrolled emissions
from open  dust sources  and typically
controlled fugitive emissions from  major
process sources such as steelmaking
furnaces, blast furnaces, coke ovens, and
sinter  machines. Moreover, preliminary
cost-effectiveness analysis of promising
control options for open  dust sources
indicated that control of open dust
sources  might result in  significantly
improved air quality at a  lower cost in
relation to  control of process sources.
(Cost-effectiveness is defined as dollars
expended per unit mass of particulate
emissions prevented  by control.) These
preliminary conclusions warranted gather-

-------
ing  more definitive data on control
performance  and costs for open dust
sources in the steel industry.
  The cost reduction potential of open
dust sources has not been missed by the
iron and steel industry. With the advent of
the Bubble Policy (Alternative Emissions
Reduction Options) on December 11,
1979 (revised April 7,1982), the industry
recognized the economics of controlling
open  dust sources as compared  to
implementing more costly controls on
stack  and process  fugitive sources  of
particulate  emissions.  However, the
Bubble Policy requires the demonstration
of  no  net gain  in emissions from an
imaginary bubble surrounding the plant.
                                            To demonstrate no net gain in emissions
                                          as  a result of a proposed  controlled
                                          trading scenario, the controlled emission
                                          rate for  an open  dust source must be
                                          estimated using the equation:

                                                    R = Me( 1-C)/2,000

                                          where: R = mass emission rate, tons*/
                                                      year
                                                  M = annual source extent
                                           •(Although EPA policy requires using metric units,
                                            certain nonmetric units are used m this summary
                                            for clarity. Readers more familiar with metric units
                                            may use the conversion factors at the end of this
                                            summary
                                                                                            e  = uncontrolled emission factor
                                                                                                (i.e., pounds of uncontrolled
                                                                                                emissions per unit of source
                                                                                                extent)
                                                                                            C   =  overall control efficiency,
                                                                                                expressed as a fraction.

                                                                                    Values for uncontrolled emission factor,
                                                                                    e, can be calculated using the predictive
                                                                                    emission factor equations shown in Table
                                                                                    1.  These  predictive  equations  are  the
                                                                                    outcomes  of  numerous prior MRI field
                                                                                    tests. Parameters (e.g., moisture and silt
                                                                                    contents of the  emitting material,  or
                                                                                    equipment characteristics) which may
                                                                                    affect particulate emission levels from
                                                                                    open sources were identified and measured
Table 1.   Open Dust Emission Factors Experimentally Determined by MRI


  Source Category         Measure of Extent
                                                             Emission Factor*
                                                          Ib/unit of source extent
                                                                                                Correction Parameters
Unpaved roads
Paved roads
Batch load-in (e.g.,
front-end loader,
railcar dump)
Continuous load-in
(e.g., stacker,
transfer station)
                      Vehicle-miles traveled      5.9
                      Vehicle-miles traveled      0.09 I
                       Tons of material loaded in   0.0018
                                                       /wdo/d)   u)   (3^5
                                                            10 /  \ 7,0007 \ 3
                       Tons of material loaded in   0.0018
Active storage pile       Tons of material put
maintenance and traffic   through storage


Active storage pile wind   Tons of material put
erosion                 through storage
                                                       1.5J235
                                                0.05   /_£_\ /_2_1  fJL-\fJ±.
Batch load-out (e.g.,
front-end loader,
railcar dump)
Wind erosion of
exposed areas
                       Tons of material loaded out  0.0018
                      Acre-years of exposed land   3.400
                                                      (7X7X7)
                                                        (f)W
                                                              so
  s = Silt content of aggregate or road
     surface material, %

  S = Average vehicle speed, mph

 W = Average vehicle weight, tons

  L = Surface dust loading on traveled
     portion of road, Ib/mile

  U = Mean wind speed at 4 m above
     ground, mph

 M - Unbound moisture content of
     aggregate or road surface
     material, %

  Y = Dumping device capacity, yd3

  K = Activity factor*

  d = Number of dry days per year

   f = Percentage of time wind speed
     exceeds 12 mph at 1 ft above
     the ground

  D = Duration of material storage, days

  e = Surface erodibility, tons/acre/year

P-E = Thornthwaite's Precipitation-
     Evaporation Index

  N = Number of active travel lanes

   I - Industrial road augmentation
     fatorc

  w = Average number of vehicle wheels

  h = Drop height, ft

  F = Percentage of time unobstructed
     wind speed exceeds 12 mph at mean
     pile height
"Particulate smaller than 30 um in diameter based on particle density of 2.5 g/cm3.
^Equals 1.0 for front-end loader maintaining pile tidiness and 50 round trips of customer trucks per day in the storage area.
"Equals 7.0 for trucks coming from unpaved to paved roads and releasing dust from vehicle underbodies;
 Equals 3.5 when 20% of the vehicles are forced to travel temporarily with one set of wheels on an unpaved road berm while passing on narrow roads;
 Equals 1.0 for traffic entirely on paved surface.

-------
during the testing process.  For sources
with a sufficient number of tests, multiple
linear regression formed the basis upon
which significant variables were identified
and then used in developing the predictive
equation.
   The annual source extent can be
estimated  by plant management from
plant  records and discussions with
operating personnel. The variable with
the least accurate data to support an
estimate of controlled emissions  is the
control efficiency. Table 2  summarizes
open dust source controls that are or have
been used in the iron and steel industry.
Control efficiency values are needed for
all the techniques shown in Table 2.


Variables Affecting
Control Efficiency
   Open  dust source control efficiency
values can be affected by four broad
categories of variables: time-related
variables, control application variables,
equipment characteristics,  and charac-
teristics of  surface to be treated.

Time-Related Variables
   Because of the finite durability of all
surface-treatment control techniques,
ranging  from hours (watering) to years
(paving), it is essential to tie an efficiency
value to a frequency of application  (or
maintenance). For measures of lengthy
durability,  the  maintenance program
required to sustain control effectiveness
should be indicated. One likely pitfall to
be avoided is the use of field data on a
freshly  applied control measure to
represent the lifetime of the measure.
   The climate, for the most part, accele-
rates the decay of control performance
adversely through weathering. For exam-
ple, freeze/thaw cycles break  up the
crust formed by binding agents; precipita-
tion washes away water-soluble chemical
treatments like lignin sulfonates, and
solar radiation dries out watered surfaces.
On the  other  hand,  light  precipitation
might  improve  the efficiency of water
extenders and hygroscopic chemicals like
calcium  chloride,  and will definitely
improve efficiency of watering.

Control Application Variables
  The control application variables affect-
ing control  performance are: application
intensity, application frequency, dilution
ratio, and application procedure. Applica-
tion intensity is the volume of solution
placed on the surface per unit area of sur-
face: the higher the intensity, the better
the expected control efficiency. However,
Table 2.   Summary of Potential Open Dust Source Control Techniques
           Source
                   Control technique
Unpaved roads and parking lots.
Paved roads and parking lots.
Material handling and storage
pile wind erosion

Conveyor transfer stations.
Exposed area wind erosion.
                 A.  Watering
                 B.  Chemical treatment
                 C.  Paving
                 D.  Oiling

                 A.  Sweeping
                    1. Broom
                      a. Wet
                      6. Dry
                    2. Vacuum
                 B.  Flushing

                 A.  Watering
                 B.  Chemical treatment"

                 A.  Enclosures
                 B.  Water sprays
                 C.  Chemical sprays"

                 A.  Watering
                 B.  Chemical treatment"
                 C.  Vegetation
                 D.  Oiling
"For example: salts, lignin sulfonates. petroleum resins, wetting agents, and latex binders.
this relationship applies only to a point,
because too intense an application will
begin to run off  the surface.  The point
where  runoff  occurs  depends on the
slope and porosity of the surface.

Equipment Characteristics
   Equipment characteristics that affect
control  efficiency  values are  those
involved  in imparting energy to the
treated surface which might  break the
adhesive bonds keeping fine particulate
composing  the surface from  becoming
airborne.  For example, vehicle weight
and speed can affect the control efficiency
for chemical treatment of unpaved roads.
An increase in either variable accelerates
the decay in efficiency. Figure 1  is a
general plot portraying the change in rate
of decay of the control efficiency for a
chemical  suppressant applied to an
unpaved road  as  a function  of vehicle
speed, weight,  and traffic volume.

Characteristics of  Surface to be
Treated

  Surface characteristics that contribute
to the breaking of a surface  crust will
affect control efficiency. For example, for
unpaved road  controls, road  structure
characteristics  affect control  efficiency.
These characteristics are: combined
subgrade and  base bearing  strength,
amount of fine  material (silt and clay) on
the surface of the road, and the friability
of the road surface material. Unaccept-
able values for these variables mainly af-
fect the  performance of chemical con-
trols.  Low bearing strength causes the
road to flex and rut in spots with the pass-
age of heavy trucks;  this destroys the
compacted surface enhanced  by the
chemical treatment. A lack of fine materi-
al in  the wearing surface deprives the
chemical treatment  of  the increased
particle surface  area  necessary for in-
terparticle  bonding. Finally,  the larger
particles of a friable wearing surface ma-
terial  simply break up under the weight of
the vehicles and cover the treated road
with a layer of untreated dust.


Project Objectives
  The overall  objective of this project was
to provide data that will document quan-
tities of particulates generated from con-
trolled open dust sources at  steel plants
and the cost-effectiveness of control pro-
cedures for eliminating or reducing emis-
sions.  Required  to achieve  the above
objective were:


   •  Field  tests to measure emissions
      from open dust sources to deter mi ne
      the efficiency of selected  control
      procedures.
   •  Evaluation  of data obtained in the
      test program to  determine the
      change  in efficiency over time.

-------
  700

                                                        Increasing Vehicle
                                                        Speed, Weight, and
                                                        Traffic Density
                                  Time After Application


Figure 1.   Effect of vehicle speed, weight, and traffic density on control performance.
   • Development of design and operat-
     ing  information on  all control
     procedures  evaluated,  including
     optimum operating procedures;
     operator and material requirements;
     design parameters; capital, operat-
     ing,  and maintenance costs; and
     energy requirements.

Report Structure
  The  report is structured as follows:
Section 2.0 gives results of a 10-plant
survey to  determine the extent of open
dust sources and controls in the iron and
steel industry; Section 3.0 contains the
methodology  and  results  of source
testing via exposure profiling; Section 4.Q
contains the methodology and result of
wind erosion testing via a portable wind
tunnel; Section 5.0 presents cost, design,
and operating information related  to
control  techniques;  and Sections 6.0
through 8.0 present references, a glossary,
and English-to-metric conversion units,
respectively.
  Numbers in the report are generally
rounded to three significant figures;
therefore, columns of numbers may not
add to the exact totals listed. Rounding to
three significant figures  produces a
rounding error of less than 0.5%.

Summary and Conclusions
  The  purpose of  this study was  to
measure the control efficiency of various
techniques used  to  mitigate emissions
from open dust sources in  the iron and
steel industry, such as vehicular traffic on
unpaved  and  paved roads and wind
erosion  of storage  piles and exposed
areas. The control efficiency was deter-
mined not only for total paniculate (TP),
but also for inhalable particulate (IP)—
particles less than 15//m in aerodynamic
diameter, and for fine particulate (FP)—
particles less than 2.5/um in aerodynamic
diameter. In addition to control efficiency
measurement, parameters defining control
design, operation, and cost were quantified.
  The  methodology  for achieving the
above goals involved the measurement of
uncontrolled and controlled emission
factors for emissions from vehicular
traffic on unpaved roads, vehicular traffic
on  paved  roads, and  storage pile wind
erosion. These sources were selected
based on an open dust source emission
inventory for the iron  and steel industry
which showed the above three sources to
contribute 70.4%, 12.7%,  and 11.5%,
respectively,  of the 88,800 T/yr  of
suspended particulate emitted by the
industry.
  The exposure profiling method developed
by  MRI was the technique utilized  to
measure  uncontrolled and controlled
emission factors from vehicular traffic on
paved  and unpaved roads. Exposure
profiling of roadway emissions involves
direct isokinetic measurement of the total
passage of open dust emissions approxi-
mately 5 m downwind of the edge of the
road by simultaneous sampling at four or
five points  distributed vertically over the
effective height of the dust plume. Size
distributions were measured at  1 and 3 m
heights downwind  utilizing cyclone
precollectors followed by parallel slot
cascade impactors. During selected tests,
size selective  inlets  mounted on high
volume samplers were also  deployed
downwind.
  Nineteen tests of  controlled  and
uncontrolled emissions  from  vehicular
traffic on unpaved roads were performed.
Ten tests  were  of  heavy-duty traffic
(greater than 30 tons) and nine were of
light-duty traffic (less than 3 tons).
  In calculating the efficiency of a control
technique from emission factor measure-
ments collected during controlled and
uncontrolled tests, the effect of testing
during different periods in the lifetime of
the control was taken into account. The
decay of control efficiency with time after
application has a number of causes, such
as track-on from surrounding integrated
surfaces and mechanical abrasion of the
treated road surface.  Accordingly, each
value of control efficiency contained in
this report includes the  time after
application that the  measurement was
taken.
  Two  control  techniques utilized  to
reduce emissions from heavy-duty traffic
on  unpaved roads were tested: (1) a 17%

-------
solution of Coherex® in water applied at
an intensity of 0.86 l/m2(0.19 gal./yd2),
and (2) water  applied at an  intensity of
0.59 l/m2 (0.13  gal./yd2). The control
efficiency for  Coherex®,  at the  above
application intensity, averaged over the
first 48 hr after application,  was 95.7%
for TP, 94.5% for IP, and 94.1% for FP. The
control  efficiency for watering at the
above application intensity, 4.4 hr after
application, was 55.0% for TP, 49.6% for
IP,  and  61.1%  for  FP.  The  control
efficiency of watering at  the above
application intensity was above 95% for
all  particle sizes  half an  hour  after
application.
  Only one control technique for emissions
from  light-duty vehicles  travelling on
unpaved roads was tested.  The control
measure was a 17% solution of Coherex®
in water  at an application  intensity of
0.86 l/m2 (0.19  gal./yd2). The control
efficiency of  Coherex® at the  above
application intensity, 25 hr after applica-
tion, was 99.5% for TP, 98.6% for IP, and
97.4% for FP. This road had been closed
to traffic for a day.  Fifty-one hours after
application, these efficiencies had decayed
to 93.7% for TP, 91.4% for IP, and 93.7%
for FP.
  Three control techniques for mitigation
of emissions from vehicles travelling on
paved roads were tested: vacuum sweep-
ing, water flushing, and  flushing with
broom sweeping.  The highest measured
values  for  the control efficiency of
vacuum sweeping, occurring 2.8 hr after
vacuuming, were 69.8% for TP, 50.9%for
IP,  and  49.2%  for  FP.  The  control
efficiency for water flushing at 2.2 l/m2
(0.48 gal./yd2),  about 40 min  after
application, was 54.1 % for TP, 48.8% for
IP,  and  68.1%  for  FP.  The  control
efficiency for flushing and broom sweep-
ing, about 40 min after application with
water applied at 2.2 l/m2 (0.48 gal./yd2),
was 69.3% for TP, 78.0% for IP, and 71.8%
for FP.
  Earlier MRI studies of  open  dust
sources in the iron and steel industry
produced data bases which were used to
develop predictive emission factor  equa-
tions. The precision factors for the  paved
and unpaved road equations were 2.20
and 1.48, respectively. When the results
of the 18 tests of uncontrolled particulate
emissions from vehicular traffic on roads
performed during  this study were added
to the data bases, the precision factors
increased to 3.95  and 1.98, respectively.
These  increases  indicate  the need for
possible  refinement of the  paved  and
unpaved  road equations based on the
'arger data bases now available.
  A  portable wind tunnel was used to
measure  uncontrolled  and controlled
emission factors from storage  pile wind
erosion. The wind tunnel involves measur-
ing the amount of emissions eroded from
a  given surface  under  a known wind
speed. MRI's portable open-floored wind
tunnel was placed directly on the surface
to be tested, and its wind flow adjusted to
predetermined centerline speeds. The
emissions eroded from the surface were
measured isokinetically at a single point
in the sampling section of the tunnel with
a sampling train consisting of  a tapered
probe, cyclone precollector, parallel slot
cascade impactor, backup filter, and high
volume sampler.
   Wind erosion from storage  piles was
quantified during 29 tests of uncontrolled
and  controlled emission factors. Nearly
all of the tests were on coal surfaces with
two control techniques studied separately:
(1) a 17% solution of Coherex® in water
applied at an intensity of 3.4 l/m2 (0.74
gal./yd2), and (2) a 2.8% solution of Dow
Chemical  M-167 latex  binder in water
applied at an average intensity of 6.8 l/m2
(1.5  gal./yd2). The control efficiency of
Coherex® applied at the above intensity
to an  undisturbed steam coal surface
approximately 60 days  before the test,
under a wind of 15.0 m/s (33.8 mph) at
15.2 cm (6 in.) above the ground, was
89.6% for TP and about 62% for IP and FP.
The control efficiency of the latex binder
on a low volatility coking  coal 2 days after
application, under a 14.3 m/s (32.0 mph)
wind speed at 15.2 cm (6 in.) above the
ground, was 37.0% for TP and  near zero
for IP and FP. However, when the wind
speed was increased to  17.2 m/s (38.5
mph), the control  efficiency increased to
90.0% for TP, 68.8% for IP, and  14.7% for
FP. The efficiency under the same wind
speed, 17.2 m/s, decayed 4 days after
application to 43.2% for TP, 48.1 % for IP,
and 30.4% for FP.
  Three  iron  and steel plants were
surveyed to determine open source
emission control design, operation, and
cost  parameters.  Design and  operation
parameters included application intensity
and frequency, life expectancy, applicator
equipment manufacturer, normal operat-
ing speed, capacity,  fuel consumption,
vehicle weight, number  and capacity of
nozzles at a specified  pressure, and
maintenance problems. Cost data included
operating, maintenance, and capital invest-
ment costs. The operating and maintenance
costs were  further divided  into  labor,
gasoline and oil, maintenance and repair,
and  depreciation costs. The capital
investment costs included purchase and
installation of primary and ancillary
equipment.
  Conclusions from this study are:
1. Open dust emissions from the entire
   integrated iron and steel industry for
   1978 were estimated at 88,800 T/yr
   of suspended particulate. The total can
   be subdivided into general categories:
      Category
Percent Contribution
Vehicular traffic              70.4
on unpaved roads
Wind erosion                15.0
Vehicular traffic              12.7
on paved roads
Continuous raw material       1.6
handling operations
Batch raw material           0.3
handling operations	

2. A decay in control efficiency with time
   after application was measured for
   most of the control techniques tested.
   This means that a reported efficiency
   value has meaning only when given in
   conjunction with a time after a specified
   application. Within 5 hr of application,
   the control efficiency  afforded by
   watering of unpaved  roads  decayed
   from nearly 100% to about 60%, but
   the control efficiency of Coherex®
   remained above 90% over the first 2
   days after application. The decay rates
   of control measures applied  to paved
   roads (which were much less effective
   than those applied to  unpaved roads)
   were high; i.e., comparable to the rate
   observed for  watering of  unpaved
   roads.
3. There is some indication that short-
   term control  efficiency  varies as a
   function of particle size,  especially for
   the paved  road control techniques
   tested. For example, vacuuming is less
   effective in controlling  fine particle
   emissions, but the opposite is  indicated
   for water flushing.
4. Wind erosion from the coarse  aggre-
   gate storage piles tested  and observed
   at iron  and steel plants is  probably
   much  less than previously  thought.
   Tests show that, for typical storage pile
   surfaces, 10m wind speeds in excess
   of 14.8 m/s (33.2 mph) are necessary
   for wind erosion to even begin. Also,
   crusts on piles and exposed  surfaces
   are very effective  inhibitors of wind
   erosion as  long as the crust remains
   unbroken. Current thinking  suggests
   that the major wind erosion problem
   exists  on  unencrusted  areas (e.g.,
   surrounding the piles, exposed areas,
   and road  shoulders) and  unpaved
   roads. Also, piles which  have dozer or
   scraper traffic on them (atypical in the

-------
   iron and steel industry) are susceptible
   to wind erosion. Finally, as would be
   expected, uncrusted piles of fine dry
   material are also susceptible to wind
   erosion.
5. The control efficiency of the latex
   binder tested for effectiveness in
   reducing wind erosion increased with
   increasing  wind  speeds.  This  may
   apply  to other wind erosion  dust
   suppressants and to a broader range of
   wind speeds than those tested, but the
   data are still too sparse to support that
   inference.
6. The optimal cost-effective  technique
   for applying open dust controls  is to
   make the application and then reapply
   only after  the  initial application  has
   decayed to zero  control efficiency.
   However, this  will yield only about
   50% control efficiency, assuming the
   technique started at 100%. In controlled
   emissions  trading (such  as offsets,
   banking, and bubbles),  much more
   than 50%  reduction  in  open  dust
   source emissions may  be needed.
   Thus,  optimization of cost-effective-
   ness in the control of open dust source
   emissions must always be considered
   in the context of a minimally acceptable
   level of control.
   There  is no clear-cut  definition of
   "best"  control  strategy for open dust
   source emissions. Two possible defini-
   tions are:
     a. That strategy which achieves the
       constraint of an acceptable level
       of emissions reduction at the
       least cost; and
     b. That strategy which achieves the
       minimally acceptable level of
       control and is the least expensive
       per unit mass of  emissions
       reduced.
     Although the cost of (b) cannot be
     less  than that of (a), (b) may indeed
     prove to  be  more desirable in the
     long term because greater offsets
     are possible and thus represents the
     most efficient use of funds.
   7. Evaluation of the emission reduction
     effectiveness  of an  open  dust
     source control  measure requires
     the  acquisition of detailed perfor-
     mance data on the control measure.
     The  performance data gathered to
     date on open  dust sources in the
     iron  and steel industry have focused
     on the efficiences of freshly applied
     control measures for given sets of
     application parameters.  Additional
     field tests would be required to
     determine the long term efficiency
     decay.
8.  As with the initial control efficiency,
   the decay rate of a control measure
   should  depend in part  on the
   application  parameters. Taking
   unpaved roads as an example, the
   frequency of application, the appli-
   cation  intensity, and  the dilution
   ratio of the  chemical  suppressant
   are of paramount importance. Also,
   there may be  a residual effect  of
   previous control applications which
   changes the shape of the  decay
   curve, although this residual effect
   may  become less  important  after
   repeated reapplication/decay cycles.
   Theoretically, a mathematical rela-
   tionship could  be developed which
   expresses  mean control efficiency
   (during the period between applica-
   tions) as a function of the application
   parameters  and the frequency  of
   application  once  a  sufficiently
   large emissions data base has been
   obtained.
9.  As part of  the emission trading
   process, a  calculated emission
   reduction requires information  on
   the uncontrolled emission factor
   and the performance of the proposed
   control measure. Except for unpaved
   roads, the  current uncontrolled
   open source emission  factor equa-
   tions listed in Table 1 are based on a
   limited number of tests. The control
   efficiency  data  base for  these
   sources is even more  limited, both
   in the small  number of  control
   efficiency values measured and the
   lack of data  on  the long-term
   efficiency of controls. This situation
   leads to corresponding  levels of
   uncertainty when implementing
   emission trades.
Metric Conversion  Factors
  Readers more familiar with  metric
units may  use the factors below to
convert the English  units used  in  this
summary.
English
Multiplied by   Metric
acre
ft
gal./yd2
Ib
Ib/acre year
Ib/ton
Ib/vehicle mile
mile
mph
ton
  0.00405
  0.305
  4.53
  0.454
  J12
  0.500
  0.282
  J.6J
  0.447
  0.907
  0.765
km2
m
liters/m2
kg
kg/km2 year
kg/tonne
kg/vehicle km
km
m/s
tonne
m3
 T. Cuscino, Jr., G. E. Muleski. and C. Cowherd. Jr., are with Midwest Research
   Institute. Kansas City, MO 64110.
 Robert C. McCrillis is the EPA Project Officer (see below).
 The complete report, entitled "Iron and Steel Plant Open Source Fugitive Emission
   Control Evaluation." (Order No. PB 84-110 568; Cost: $17.50, subject to
   change) will be available only from:
         National Technical Information Service
         5285 Port Royal Road
         Springfield, VA22161
         Telephone: 703-487-4650
 The EPA Project Officer can be contacted at:
         Industrial Environmental Research Laboratory
         U.S. Environmental Protection Agency
         Research Triangle Park, NC 27711

-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
                                                                                                             <
Official Business
Penalty for Private Use $300
                                   1111
                                   11U
                                    Ull
                                    uii
                                                                         ^011*^
                                                                           . PH t'-'
                                                                                - S
          P5   000032**
          U S  ENVIR  PROTECTION
          REGION 5 LIBRAKY
          250  S DEARBORN  STREET
          CHICAGO  II 60604
                                                                   111!
                                     ,,  / -         %   PTM
                                    I   /           \   HJ1
                                       (  H'i  " '3'i     PKWE
                                   itii  v  "        ;   is$3c
                                                                         U.S. GOVERNMENT PRINTING OFFICE: 1984-759-102/833
                                                                                                            •

-------