&EPA
United States
Environmental Protection
Agency
Center for Environmental
Research Information
Cincinnati OH 45268
EPA-600/8-84-032
January 1985
Research and Development
User's Guide:
Fugitive Dust Control
Demonstration
Studies
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EPA-600/8-84-032
January 1984
USER'S GUIDE
FUGITIVE DUST CONTROL DEMONSTRATION STUDIES
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Center for Environmental Research Information
and
Office of Air Quality Planning & Standards
CENTER FOR ENVIRONMENTAL RESEARCH INFORMATION
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
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NOTICE
This document has been reviewed in accordance with the U.S. Environmental
Protection Agency's peer and administrative review policies and approved for
publication. Mention of trade names or commercial products does not consti-
tute endorsement or recommendation for use.
11
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FOREWORD
Under certain circumstances, sources of air pollution may be able to meet
their obligations under the Clean Air Act by the use of the bubble concept in
which emission points can be controlled to a greater or lesser degree than
otherwise required, as long as the total plant emissions are within estab-
lished limits. Strict controls can often be applied to non-process fugitive
(also called nontraditional) particulate to emissions to allow a lesser
degree of control for stacks and vents under a bubble proposal.
State and local agency officials are responsible for determining the validity
of bubble proposals. Thus, these officials must be in a position to deter-
mine if claimed reductions in fugitive emissions from such sources as
roadways and storage piles can be substantiated for the control methods
proposed. There are many studies available to the official that discuss the
effectiveness of various control techniques for nontraditional particulate
emissions.
This User's Guide provides state and local agency officials and those respon-
sible for conducting fugitive particulate demonstration studies insight into
the validity of recent studies. It also stresses the considerations of
importance when planning this type of study. From the data presently
available, it was not possible to develop quantitative emission factors or
control efficiencies for the various control alternatives.
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ACKNOWLEDGMENTS
Many individuals contributed to the preparation and review of this publica-
tion. The author was Thomas W. Beggs, P.E., Senior Engineer, JACA Corp.,
Fort Washington, Pennsylvania. Reviewers included Brock Nicholson, EPA-
OAQPS, Research Triangle Park, North Carolina, Kenneth R. Woodard, EPA-OAQPS,
Research Triangle Park, North Carolina, and Keith Rosbury, Denver Branch
Manager, PEDCo Environmental, Inc. (now PEI), Denver, Colorado.
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TABLE OF CONTENTS
Chapter
Page
FOREWORD 111
ACKNOWLEDGMENTS. 1v
1 INTRODUCTION l
2 GUIDELINES FOR CONDUCTING FUGITIVE DUST CONTROL
DEMONSTRATION STUDIES 3
2.1 Study Design 3
2.2 Sampling and Analysis ! ! ! 4
2.3 Statistical Analysis of Results ! ! ! ! 6
2.4 Development of Emission Factors and Control
Efficiencies ..... 7
2.5 Optional Investigations. '.'.'.'. 7
3 CASE HISTORIES 9
3.1 Recent EPA Demonstration Studies ........ 9
3.1.1 Denver, Colorado ...! 9
3.1.2 Minneapolis, Minnesota .....!!! 13
3.1.3 Portland, Oregon * 17
3.2 Other Studies. .'.'.".* 20
3.2.1 Philadelphia, Pennsylvania ....!!! 20
3.2.2 Bangor, Maine. 20
3.2.3 Kansas City, Kansas '.'.'. 21
3.2.4 Lincoln, Nebraska 21
3.2.5 Clark County, Nevada ] 22
3.2.6 Erie County, New York | [ 22
3.2.7 Allegheny County, Pennsylvania .....* 23
3.2.8 The Road Carpet Study 24
3.2.9 The Iron and Steel Plant Studies . . ! ! 24
4 CONCLUSIONS 27
REFERENCES 2g
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Chapter 1
INTRODUCTION
The Clean Air Act Amendments of 1977 require states to submit to the U.S
Environmental Protection Agency (EPA) a revised State Implementation Plan
(MP) describing the state s plan for expeditious attainment of the National
Ambient Air Quality Standard (NAAQS) for all areas within the state. The
specific EPA requirements for the revised SIPs (published in the Federal
Register, April 4, 1979 and in subsequent EPA documents) include requirements
for addressing several classes of particulates, especially in nonattainment
areas: stack emissions, process fugitive dust, and nontraditional fugitive
dust (or nontraditional particulate matter). Nontraditional fugitive dust
includes urban fugitive dust, dust reentrained from road surfaces, and dust
created by construction activities.
For those areas which have not attained the NAAQS for particulates and in
which fugitive dust contributes to the violation of the particulate NAAQS,
^TUNStu adopt the requirement that reasonably available control technol-
ogy (RACT) be used to control traditional sources of fugitive dust (process
fugitive dust); in addition the SIP must contain a schedule for the study and
eventual adoption of controls for nontraditional sources of particulates.
Many such RACT-plus" studies have been conducted across the country to
demonstrate the effectiveness of proposed technologies in controlling these
nontraditional sources.
Because of the large number of nonattainment areas requiring demonstration
studies and considering the cost of these studies, EPA commissioned a work-
T£ I,to Provide guidance in designing and executing a proper study [1].
The Workbook was published in March 1981. The guidelines set forth in the
Workbook are to ensure that defensible results are obtained from the study,
and that the results can be exchanged among jurisdictions, thus minimizing
duplication of effort. The Workbook stresses two critical guidelines that
demonstration study to be successful: (1) The study
the amount and type of data generated will be suf-
objectives of the study; and (2) The data must be
rigorous statistical analysis.
must be followed for any
design must ensure that
ficient to realize the
subjected to the proper,
In addition to the Workbook, EPA has also recently sponsored or partially
funded a number of these demonstration studies to evaluate the effectiveness
of a wide variety of nontraditional particulate control systems.
studies were conducted in Denver, Colorado; Minneapolis,
Portland, Oregon.
These
Minnesota; and
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Of the studies reviewed, many were found to be deficient in their analyses
when compared to the Workbook guidelines. Generally speaking, in the studies
with valid analyses, control techniques that were evaluated were not highly
effective. Further, many of the studies neglected the critical time factor;
that is, the study analyzed the immediate effect of the control but failed to
analyze the decay in effectiveness over time.
The objectives of this User's Guide are to:
o Verify that the Workbook is a firm foundation to build a demon-
stration study upon
o Discuss the study variables that must be taken into account'in
the study design . -'....'
o Summarize the major fugitive particulate studies that have been
done to date ,..,.-
o Make state and local agency personnel aware that control effi-
ciencies reported in some studies may be unduly optimistic.
This Guide is therefore of particular value to those designing and implement-
ing future studies as well as to state and local agency personnel reviewing
permit applications in which the control of nontraditional particulate
sources is an integral part. ;
Chapter 2 of this Guide reviews the Workbook's guidelines on the design and
implementation of demonstration studies. The guidelines include a consider-
ation of:
o Study design :
o Sampling and analysis
o Statistical analysis of results
o Development of control efficiencies
o Optional investigations
o Usefulness to state and local agencies.
The review of case histories is found in Chapter 3, which provides -detailed
descriptions of the three recent EPA-funded demonstration .studies and brief
descriptions of a number of earlier studies.
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Chapter 2
GUIDELINES FOR CONDUCTING FUGITIVE DUST CONTROL DEMONSTRATION STUDIES
The proper design, implementation, and interpretation of the results of a
demonstration study are essential to the defensibility and usefulness of
S* JM? S6fi0n summarizes the Sidelines set forth in Workbook
Studies for Control of Nontraditional Particulate Sources [1].
9 In' tif ^^ ?? ? yardst1ck against which the project descriptions
r~ H I J ,Ca!6 hlstones are measured; The Workbook was thoroughly
reviewed and found to provide excellent guidance for a demonstration study
which, when rigorously followed, should yield defensible results. Y
2.1 STUDY DESIGN
The design of a demonstration study is critical to the study's ability to
produce clear, valid, and defensible results which can be applied to circum-
stances outside the the study itself. The study design musf begin wUh
the objectives .of the study, such as "to determine the effectiveness of
roads * W|LnHPPtfS1°n-iChKe^CalS for Controlling emissions from unpaved
roads. Second, the availability of data related to this objective must be
ascertained m order to see whether the demonstration study Is warranted
L^ht lsPwarranted1 onl* wh*n the data needed are not available or are
unusable. For example, .all available data on a particular type of control
approaches described below is most appropriate for determining the effect
^0-^; ^
uniform emissions from i
"el
«.
suited for averaging widely variable emissions from a large area of sources
£u>Yr^ -s^s- ra^^-sssar ^?; srss. S
directly to the areas in which monitors are located. However, the number
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and location of monitors used are critical elements in the study design if
the test results are to be used tp predict area wide effects. Most nontra-
ditional particulate studies will probably be receptor oriented since
they involve impacts in a large area.
The next step is to select one of three types of study designs described
below on the basis of implementability and usefulness for subsequent anal-
ysis. This step must be closely integrated with the selection of the statis-
tical analysis technique which will be used later; these techniques are
described below. If the type of design is ill-chosen or cannot be followed
meticulously throughout the course[of the study, the statistical analysis of
field data may be hampered or even invalidated.
A Type 1 design consists of a sihgle study area sampled during an uncon-
trolled period and during a controlled period. This design assumes that
all parameters other than the control parameter remain constant from the
first to the second period. Therefore, this design is only effective if the
other variables (such as weather £nd site activities) can be shown through
statistical analysis to not influence the results.
A Type 2 design consists of simultaneously sampling two study areas, one with
and one without controls. In this! manner, the variables that can affect the
uncontrolled and controlled emissions (other than the control itself) will be
nearly identical.
A Type 3 design consists of two study periods: during the first period one
study area is controlled while the other area is not controlled; during the
second period, the roles are reversed. Although more expensive to conduct, a
Type 3 design is usually preferable to Type 2, and is called for if source
activities vary widely or if for other reasons, such as an expectation of
seasonal effects, the study areas cannot be considered identical. The
greatest disadvantage of this type is the possibility that the effect of
controls in one area might be carried over into the first part of the second
period when that area is said to be uncontrolled.
Another'step in the planning stage is to detail the specifications for
applying the controls, including the area to be administered, and the fre-
quency, methods, and rates of application. These specifications must include
incidental instructions that may japply, such as a prohibition of parking
during street-cleaning.
2.2 SAMPLING AND ANALYSIS
The success of the study is dependent on the coordination of all parties
involved to ensure that the sampling program is carried out in accordance
with the study design. It is particularly important that those responsible
for implementing the source controls do so at the agreed-upon time. A Type 1
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or 3 study may be irreparably damaged if sampling during the control period
cannot be completed because of a failure to completely implement controls
during the scheduled sampling period.
A primary requirement for the study is that enough samples are taken to
demonstrate statistically that the control method does or does not bring
about the desired effect. If too few samples are taken, results will be
inconclusive. The Workbook provides detailed instructions for calculating
the minimum number of samples. The design must also allow for the loss of
samples which will be dropped due to errors.
The frequency of sampling generally represents a compromise between the time
period available for the study and the resources and level of effort that can
be committed to the project. For source-oriented studies, any convenient
sampling period is selected, provided it is representative.
oriented studies, daily sampling is preferable, especially
effect of variables whose effects may be transitory, such as
For receptor-
in tracking the
the application
of chemical dust suppressants. The sampling period's selected are normally 24
hours in length to correspond with daily cycles of weather, vehicle traffic
and so on.
Determining the number of sampling sites is generally a site-specific
consideration. Source-oriented studies can use a single monitoring site.
However, at least two monitoring sites are recommended for each study area
for a receptor-oriented study: normally one monitoring site is located
near the source (or sources) to measure the impact of the control method
in a small area, and an additional monitoring site is located up to several
hundred meters from the source to measure the impact in a larger area
A background site located upwind from the source is also advisable when
studying ambient impacts that are expected to be small. The actual location
of the instruments should follow guidelines such as those found in the
Workbook and similar references. These guidelines address concerns such as
height above the ground, distance from buildings, and distance from trees.
The standard sampling instrument for a receptor-oriented study is the high
volume sampler, or hi-vol, which measures total suspended particulates (TSP
less than 30 microns in diameter). If an important parameter in the study is
the proportion of participate matter between specific size ranges, such as
inhalable particulates (IP, less than 15 microns in diameter) or fine partic-
ulates (FP, less than 2.5 microns in diameter) options are available.
it two size fractions are required, a dichotomous sampler can be used- if
more fractions are desired, a cascade impactor with several stages can be
used in conjunction with a hi-vol. It should be mentioned that cascade
impactors suffer from the problem of "particle bounce" in which large par-
ticles migrate to lower stages of the instrument, thereby significantly
biasing the results toward the small particle size. ".cdntiy
The specifications for every demonstration study must explicitly delineate
detailed quality assurance procedures. A quality assurance checklist such as
that published in the Workbook must be strictly observed during the sampling
and analysis phase of the study. amjjuny
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2.3 STATISTICAL ANALYSIS OF RESULTS
Four methods of statistical analysis have been or could be used to interpret
the results of demonstration studies when a controlled source is compared to
an uncontrolled source. These analyses include the paired t-test, analysis
of variance, analysis of covariance, and multiple linear regression analysis.
The paired t-test compares the averages of the controlled source data with
the averages of the uncontrolled source data and analyzes the differences
to determine whether or not the control method has caused a real difference.
Analysis of variance compares the magnitude of two or more sample variances
to determine whether they are different at a predetermined level of signifi-
cance, for example, with 90 percent confidence. Analysis of covariance is an
extension of analysis of variance; variations attributable to measured
variables (covariates) other than the control variable are subtracted out
before testing for significance. This allows conclusions to be drawn con-
cerning the effect of the controls as well as of each of the covariates.
Multiple linear regression analysis derives an equation relating an effect
(such as a concentration) to a series of independent variables. The results
of this analysis indicate which, if any, of the independent variables are
correlated to the effect. The reader is referred to the Workbook for more
detailed discussion of these methods of statistical analysis.
The following is a summary of these methods and their suitability to the
three types of demonstration studies:
Technique
Study Design
Applicability
Requi rements
Limitations
Paired t-test
Analysis of
variance
Analysis of
covariance
Multiple
linear
regression
Type 2
Types 1, 2, 3
Types 1, 2, 3
Types 1, 2, 3
Paired data
Sampling must be
done for combi-
nations of vari-
ables
All independent
variables of
interest (covar-
iates) must be
measured
All independent
variables of
interest must
be measured
Only two data sets
can be compared
Period of time re-
quired cannot be
determined because
variables are not
controllable
More difficult to use
for Types 1 and 2
than for Type 3
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It is apparent from the above table that the statistical analysis method
selected for a demonstration study ,is highly dependent on the type of
study design as well as on the number of variables the designer is able and
willing to measure. Obviously, the study design and corresponding statis-
tical analysis method must be selected together in order to meet the study
objectives in the most cost-effective manner.
Once selected, the statistical analysis method must be rigorously followed
and the results compiled in a we11-documented fashion. Furthermore, each
method requires assumption of a confidence level; for example, a finding of
effectiveness of a control method at a 95 percent confidence level is a
stronger endorsement of the method than a similar effectiveness at an 80
percent confidence level. The confidence level must be clearly delineated
when reporting the results in order for the reader to judge the impact of the
findings and conclusions, as well as to be able to compare findings among
similar studies, and to decide whether the results can confidently be extrap-
olated to a full-scale implementation of the control method.
2.4 DEVELOPMENT OF EMISSION FACTORS AND CONTROL EFFICIENCIES
The results of a demonstration study are usually expressed in the following
form: It can be said, with a certain confidence level, that the effect of a
control system lies between A and B, where A and B are reductions in ambient
particulate concentrations from the level when the source was uncontrolled.
The study may go on to provide emission factors or emission factor algorithms
relating emissions to variables such as traffic density or days since precip-
itation. In order to be useful, emission factors developed in this manner
must be firmly grounded in the results of the study and must not merely
represent a restatement of previously developed equations that are not
completely verified by the present study.
The result that is probably most useful to the permitting process is the
development of control efficiencies. These should be based strictly on the
effects data described above and again, they should not be influenced
by previous work or unwarranted assumptions. Furthermore, any limitations on
the application of the developed control efficiencies must be clearly stated.
For example, a control efficiency for the use of a chemical dust suppressant
on unpaved roads applies only at the application doses and frequencies
employed in the demonstration study and only for that particular suppressant.
2.5 OPTIONAL INVESTIGATIONS
Optional investigations are defined here as activities other than general
particle size analyses (TSP, IP, and FP) that may be conducted for reasons
specific to the demonstration study. One such study might be an elemental
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analysis of samples to provide corroborating data for other similar studies
or to identify and remove interferences from the study. For example, a
significant portion of collected particulate matter in an urban location may
comprise nonsoil elements, or one or more soil elements may be present in
suspiciously high concentrations. Either of these phenomena may be traceable
to an overwhelming background source, the contribution of which, if quanti-
fiable, could be subtracted from the data in question to provide a clearer
estimation of the effectiveness of control.
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Chapter 3
CASE HISTORIES
This chapter presents case histories of demonstration studies designed to
evaluate the effectiveness of control techniques for participates. These
case histories are intended to illustrate the application of the study
guidelines presented in the previous section to actual demonstration studies.
The design, implementation, and conclusions drawn from each of the cases are
presented and critiqued, with the hope that this information will assist
others in the design of similar studies. The case histories are divided into
detailed accounts of recent EPA-sponsored studies in Denver, Minneapolis, and
Portland, Oregon, and less detailed accounts of earlier studies.
3.1 RECENT EPA DEMONSTRATION STUDIES
For each of these case histories, an account is provided of the circumstances
prompting the study, the reasons for the choice of particular study design,
the implementation of the study, and the conclusions drawn from the results.
The methods and procedures employed in each study are then compared with the
criteria and guidelines established in the Workbook. In these studies many
results could not be substantiated due to such factors as the inability to
carry out a study as designed, the effect of interferences, and less than
adequate statistical analysis of sampling results. State and local agency
personnel should be aware of these deficiencies both in reviewing compliance
plans based on these studies and in designing future studies.
3.1.1 Denver, Colorado
The Denver study [2] was conducted for the Colorado Division of Air Pollution
Control during the winter of 1980-81. The study actually consisted of two
independent studies designed to address the hypotheses that (1) ambient
concentrations of particulate matter can be reduced by substituting road salt
for sand; and (2) ambient concentrations of particulate matter can be reduced
by later cleaning up the sand used on the snowy roads.
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No large-scale demonstration studies of this type had been conducted pre-
viously despite the widely held belief that the use of sand for snow control
may be detrimental to local air quality. The first hypothesis was tested in
Lakewood, a suburban area near Denver; the second was tested in the City
of Denver. Both the suburban and urban locations were primarily residential.
In both locations, concentrations of TSP, IP, and FP were measured at
three distances: near-street (10 to 11 meters from the street); off-street
(50 to 70 meters from the street); and neighborhood (greater than 200 meters
from the street). The results of the studies indicated a slight improvement
in air quality for TSP and FP at the near-street location when the sand was
removed,. Substituting salt for sand failed to show any improvement in air
quality; in fact, a slight degradation of TSP air quality was observed
at the near-street and off-street locations. These results are summarized
below.
Control Method
TSP
Air Quality Improvement
TF
Salt Substitution (Lakewood, CO)
Near street
Off-street
Neighborhood
Negative
Negative
NSS
Sand Removal (Denver, CO)
Near street Positive
Off-street
Neighborhood
*Not statistically significant
NSS* NSS
Not tested Not tested
Not tested Not tested
NSS Positive
No conclusions possible
No conclusions possible
Study Design. Both portions of the study used the receptor-oriented ap-
proacn, wnich was appropriate given that a wide variation in emission rates
was anticipated. In order to partially overcome the limitations of this
approach, monitors were located at the three distances from the streets
described above, thus eliminating the temptation to assume that the partic-
u 1 ate concentrations were consistpnt thmunhmit +ha an+-;^Q neighborhood
concentrations were consistent throughout the entire
The study design selected for the salt substitution case was Type 3. Two
sites were monitored concurrently, one using salt and the other sand; the
process was reversed for the second period. The sand removal study was also
to have been a Type 3 design, but it was essentially reduced to a Type 2
design because street cleaning activities were not performed as planned.
Meaningful results could have been obtained in the Type 2 design had the two
areas been shown to be essentially identical in terms of meteorology, back-
ground concentrations, interferences, and so on. However, this was not found
to be true.
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The actual areas selected for the two studies appear to be appropriate.
Each was primarily residential, which tends to minimize interferences from
background sources. The paired sites were similar in terms of land use
patterns and number of paved streets. Those sites in the salt substitute
case differed somewhat in terrain; site A was a valley and site B a grassy
hill. However, because a Type 3 design was used, this inconsistency would be
inconsequential.
The concentration of TSP at each of the four monitoring stations was measured
by a hi-vol sampler with a standard glass filter. A dichotomous sampler with
a teflon filter was used to measure concentrations of IP and FP at the
near-street monitoring stations only. ; For the sand removal study, a back-
ground monitoring station, consisting of a hi-vol sampler and a dichoto-
mous sampler, was maintained in another part of downtown Denver. Sampling
was conducted for 24-hour periods from mid-day to mid-day, allowing sample
collection and restarting of monitors during normal working hours. The
location and operation of monitors appear to be adequate. The duration of
each portion of the study also appears to be adequate for generating enough
data for a rigorous statistical analysis.
Sampling and Analysis. As mentioned previously, the sand removal study
suffered from a lack of coordination which resulted in a Type 3 design
actually being conducted as a Type 2 design. Other than this, the imple-
mentation of controls proceeded as planned. The sampling and analysis plan
provided sufficient samples for statistical analysis of results, even though
the study was terminated after five months instead of the six months which
had been planned.
Extensive quality assurance procedures were established and followed.
These covered equipment maintenance and calibration, sampling procedures,
laboratory procedures for filter preparation and analysis, and data handling.
Independent audits were performed to check hi-vol flowrates and filter
weights, and to ensure the reproducibility of the hi-vol results. The audit
of hi-vol filters essentially verified the procedures used; some problems
with reweighing of dichotomous filters were reported even though a higher
than normal reweighing tolerance was used. The report provides the proper
caution concerning interpretation of these results in light of potentially
large weighing errors.
Analysis of Results. For the salt substitution study the concentrations of
TSP, IP, and FP for all sampling days were calculated directly from the
laboratory results. For each site and period, the mean concentrations of all
data were then calculated. The differences in ambient concentrations between
each pair of sites were averaged for both periods and used in a multiple
linear regression analysis. The regression analysis was used to determine
the variables, other than salt substitution, that may have affected air
quality.
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For the sand removal case, the multiple linear regression technique could not
be used because the expected Type 3 design turned out to be a Type 2 design.
Instead, the paired t-test was used, requiring the calculation of mean values
and standard deviations for two groups of data (with and without sand re-
moval) as well as the average difference of paired data values. As mentioned
previously, the Type 2 design is only valid if the two areas can be shown
statistically to be identical. ;The paired t-test was thus first used
for this purpose and revealed that the sites were identical only at the
near-street locations. Therefore, no conclusions concerning the control
method could be made concerning the other two distances. Although a somewhat
standard 80 percent confidence level was used for discussing the significance
of the salt substitute results, the sand removal results are presented in
terms of a 95 percent confidence level. It is not clear why two different
confidence levels were used. j
In general, the study presents conclusions properly and does not extrapolate
the results beyond the constraints of the study. The most useful conclusion
is that neither control method was shown to provide a significant air quality
benefit. Note on the summary table (p. 10) that 14 of the 18 cases cannot
be discussed in terms of the effectiveness of the control. These cases are
eliminated for one of three reasons: samples were not taken for that parame-
ter (not tested); the type of study1 design implemented precluded conclusions
from being drawn (no conclusion possible); or the results were not statis-
tically significant.
Emission Factors and Control Efficiencies. The uncertain nature of the re-
sults prohibited the development of jemission factors and control efficiencies.
i
Optional Investigations. Selected [filters were further analyzed to define
the nature of the particulate matter collected. Some hi-vol filter samples
were ashed to determine percent volatile material, and some dichotomous
filter samples were subjected to elemental analysis by X-ray fluorescence.
The presence of the ten elements for which the filters were analyzed has been
explained in terms of their expected sources: soil, fuel combustion, automo-
bile exhaust, and application of sand or salt. However, in general these ten
elements represented only 10 to 25 percent of the total mass of the samples.
Therefore, with no further analysis, no conclusions regarding interferences
from unexpected elements are possible. A qualitative discussion of the
variation of the ten elements across sites and time periods is presented, but
does not achieve any specific objective. A brief discussion of volatile
content is also provided.
Usefulness to State and Local Agencies. As mentioned earlier, neither
control method was shown to be effective in improving ambient particulate
air quality, given the limits of the test program. Therefore, one obvious
use of the results is to encourage state and local officials to be skep-
tical of favorable claims made for [these control methods applied in similar
situations.
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Future studies of this type would benefit from coordination and planning of
the implementation of controls. No conclusions for the off-street and
neighborhood locations were possible for the sand removal study because
immediate cleanup of sand was not practiced. If a control measure is
to be implemented by other than the study contractor, a firm commitment with
the performing organization must be made before testing begins. In addition,
the contractor's performance must be monitored throughout the study period.
The Denver sand removal study can be somewhat useful in providing background
data on the uncontrolled levels of small particulate in anticipation of a
size-specific standard such as the suggested PM-10 (particles less than 10
microns) standard. In both study areas at the near-street locations, con-
centrations of IP (less than 15 microns) and FP (less than 2.5 microns) were
determined by dichotomous samplers, which would permit interpolation to the
approximate fraction of PM-10. However, because of possible interferences,
it is perhaps wise to view this interpolated PM-10 value as an order-of-
magnitude estimate.
3.1.2 Minneapolis, Minnesota
The Minneapolis study [3] was conducted for the Minnesota Pollution Control
Agency. Field measurements took place in the summer of 1982. The objectives
of this study were to assess the impact of construction-related fugitive dust
on ambient air quality in an urban area, and to assess the effectiveness of
water spraying as a control method for this source. The study was needed
because at the time, little data was available on fugitive dust from con-
struction activities or on the effectiveness of water spraying as a control
method. Concentrations of TSP and IP were measured upwind and downwind of
the construction activity; concentrations of FP and PM-10 were interpolated
from U>g-normal plots of the data. Because of problems encountered in
executing the study, no firm quantitative conclusions were justified con-
cerning the effectiveness of watering to control construction-related dust.
Study Design. A receptor-oriented approach was planned, in which monitors
were placed at distances of 25 and 50 meters upwind and downwind (north to
south orientation) of the road construction right-of-way. Monitors were
deactivated during periods when the wind direction differed by more than
67.5 degrees from the north-to-south line.
The study was conceived as a Type 1 design with one area to be monitored
during consecutive periods of no control followed by control. During the
early stages of the road construction, water spraying of the dirt surface,
though planned, was not conducted; a modest amount of watering was done later
when the road had a gravel surface. The result was that the sampling data
collected before and after the application were for two essentially different
sites, thereby ruling out a meaningful statistical analysis of the effect of
control. Therefore, the effect of water spraying could not be evaluated
and an alternative analysis based partly on previous work was used.
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The selection of the site appears to have been appropriate, as it consisted
of the full range of activity frbm site clearing to paving with hot mix
asphalt. The monitors were properly oriented, parallel to the prevailing
wind direction. Parti oil ate concentrations upwind and downwind were measured
by hi-vol samplers fitted with a 15-micron selective inlet and a 5-stage
cascade impactor. The TSP and IP concentrations were thus measured directly,
while PM-10 and FP were determined by extrapolation or interpolation from the
particle size curve developed by the cascade impactor results. Monitors in
both directions were in areas with ground cover provided by crops and were
mounted such that the inlets were two meters above the ground.
Sampling and Analysis. As discussed above, an insufficient number of
samples were taken during watering to provide for a statistical analysis of
the effectiveness of the' control technique; furthermore, the samples taken
for the controlled and uncontrolled conditions were for different surfaces
(gravel and dirt). Part of the prpblem was the short duration of that part
of the construction which was performed on dirt (approximately 35 days).
This would have made it difficult to collect enough samples even if watering
had been done for as much as half of this period.
The sampling and analysis procedures followed appear to have been adequate.
Extensive field measurements of meteorological variables such as wind speed
and direction, temperature, and humidity were taken, as well as other inde-
pendent variables such as vehicle speed and number of passes. Samples of the
actual working surface were collected for laboratory analysis.
Extensive and appropriate quality assurance procedures were followed covering
equipment siting, operation and maintenace, instrument calibration, and lab-
oratory procedures. Audits of unexposed and exposed filters were conducted.
Analysis of Results. The concentrations of TSP and several particle size
fractions were directly calculated from the the hi-vol 15 micron inlet, and
from the cascade impactor catches. The data were plotted on a log-normal
distribution curve, from which the concentration of PM-10 and FP were then
interpolated. During this procedure, an unexpectedly large amount of par-
ticulate matter bypassed the cascade impactor stages and was found on the
backup filter (particle bounce). ' A calculation, presumably verified in
previous work, was used to correct this problem.
A possible interference was noted in the presence of a significant amount of
black particulate matter in the smaller size ranges. It was speculated that
the source was diesel exhaust from heavy construction equipment. This
speculation was not verified by laboratory analysis.
Meteorological and other independent variables were averaged and tabulated.
Water application rates were highly variable in duration and intensity and
were thus normalized and reported as liters per square meter per hour.
Originally, it was intended that an analysis of variance would be used to
statistically analyze the effectiveness of the control. However, because of
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the problems in carrying out the original study design, this technique could
not be used. Instead, a multiple linear regression analysis was used to
attempt to relate ambient particulate concentrations to various independent
variables.
A regression model was proposed which related concentration to three indepen-
dent variables silt content (percent less than 200 mesh), traffic density
»»* surface moisture that were selected from a preliminary correlation
and
analysis. However, it is not clear why vehicle weight was not included in
this model, since this variable exhibited a greater correlation coefficient
than did surface moisture.
The regression model was then run with traffic density data from the field
and values for the two other variables from laboratory tests. The results
were expressed as values for a coefficient and for individual exponents for
each particle size (TSP, IP, and PM-10). Correlation coefficients were then
calculated which revealed that a large percentage of the variation in concen-
trations was statistically related to the three variables. Surface moisture
was found to be the least dominant variable, becoming even less important at
greater distances (50 meters versus 25 meters).
Emission Factors and Control Efficiencies. Two approaches were used to
analyze the effect of controls, focusing on the data for the 25-meter
sampling distance. (Apparently because of alternate approaches used, the
50-meter data was not analyzed in this manner.) In the first approach, the
regression analysis was used to calculate particulate concentrations near the
gravel surface. This analysis was based on six data points for watering and
one for no control. The resulting control efficiencies are on the order of
bU percent but are of limited use, as they are based on such a small sample
size. Furthermore, no account was taken of the decay in effectiveness over
11 me.
The second approach involved a laboratory experiment in which three represen-
tative samples from field sites were watered in an attempt to simulate the
desired watering program that was not carried out. Two application rates
were used: the field-measured normalized rate and a rate twice this amount.
bravimetric analysis of samples before and after watering yielded surface
moisture values which were inserted along with the other variables into the
regression equations to yield concentrations before and after watering and
thus the control efficiency. The resulting control efficiencies ranged from
41 to 70 percent (again without regard to decay with time); however, because
these results are based on a laboratory simulation, they cannot be applied
directly to actual field situations.
The conclusions presented in this study must be tempered with an understand-
ing of the actual conduct of the study in relation to the original study
design. One might justifiably state that the study has established that road
construction activity causes a "significant and measurable impact on the
ambient air quality" in terms of fugitive dust. It is perhaps also fair to
conclude that the regression model, complete with constants for each particle
size distribution, reasonably relates this impact to surface silt content,
surface moisture, and traffic density. However, the study's conclusion that
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approximately 50 percent control can be achieved by watering is not totally
supported by the results of the study because one determination was based on
very limited field data for a gravel surface and the other determination was
based on a laboratory experiment that may or may not accurately reflect
conditions for an actual dirt road ;in a construction area. The laboratory
experiment is unreliable in that it represents a hybrid approach that sets
out to calculate an ambient concentration from data derived partly from the
field and partly from the laboratory. This conclusion also says nothing
about decay in effectiveness with time.
The study's conclusion that watering is the only viable control strategy for
fugitive dust emissions from construction activities is not warranted because
this hypothesis was not tested by this study. Also, the study's conclusion
concerning the black particulate matter found on filters is more of a hypo-
thesis to be investigated at a later date, in that the association of the
black particles with diesel exhaust! is a supposition, rather than a conclu-
sion supported by analysis. !
Optional Investigations. Two optional investigations were conducted as part
of the demonstration study. The first was an emissions inventory of the area
around the monitoring site. The only apparent and direct result was that no
other significant sources of fugitive dust were found within one kilometer of
the construction site. The contribution of sources within ten kilometers
of the construction site was estimated using previously developed emission
factor algorithms for wind erosion,! vehicular traffic, and material storage
piles. These results were published in an appendix, but were not directly
applied to the analysis.
The second optional investigation was a determination of mud or dirt carry-
out, that is, reentrainment of dust carried onto paved roads by construction
traffic. Samples were taken by portable vacuum cleaners at three nearby
sites. Surface loadings for each sample were calculated, and each sample was
analyzed in the laboratory for silt content. These results were presented
but, again, were not directly applied to the analysis. Rather, they were
collected as the first part of a jmore comprehensive study to have been
completed later. ;
Usefulness to State and Local Agencies. A true Type 1 analysis was not
achieved in the Minneapolis study primarily because of a failure to implement
controls during the control period! of the study. As a result, indirect
analyses were used involving a laboratory analysis and the limited field data
collected. The latter included only one sample for the control period
and one other for a different surface from that tested under the uncon-
trolled scenario. Consequently, the conclusions drawn from this analysis
must be considered tentative at best. It is particularly inadvisable to
apply the conclusions to actual field sites because they are based on
a hybrid (field/laboratory) experimental approach.
A problem raised by the study is I that of interference by either a point
source or a traditional fugitive source in the study area. It is important
once a potential interference has been found that the source be identified
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and confirmed so that its contribution can be removed in the analysis of
results. This should have been done once a significant amount of black
particulate matter was noted on the sample filters. Speculation on the
nature and source of potential interferences does not enhance the usefulness
of the results.
The Minneapolis study could provide useful data on the
particulates from road construction under uncontrolled
not measured directly, PM-10 values inferred from the
relatively accurate because they are determined by
cascade impactor particle size distribution consisti
sizes. The top size is 7 microns, which is relatively
more, the extrapolation is done for large particle
for the smaller particle sizes where there is greater
the particle bounce problem.
distribution of PM-10
conditions. Although
:test data should be
extrapolation from a
ng of five particle
close to 10; further-
diameter rather than
uncertainty caused by
3.1.3 Portland, Oregon
The Portland study [4] was conducted in 1981 under the direction of the
Department of Public Works of the City of Portland, Oregon. The objective of
this study was to determine the effectiveness of daily vacuum sweeping of the
curb lane of city streets in controlling particulate concentrations. Concen-
trations of particulates greater and less than 2.5 microns were determined in
the two study areas. The study was unable to demonstrate any relationship
between vacuum sweeping and air quality.
Study Design. Previous studies investigating the effectiveness of vacuum
sweeping in improving the particulate air quality were not conclusive
because they usually relied on remote measurements of TSP and because they
failed to account for independent variables relating to meteorology and
traffic.
This study employed a receptor-oriented approach, which is appropriate
for this type of study because emissions are distributed over a wide area
and are expected to vary significantly. Dispersion modeling was to have been
used to project the results to a wider area.
A Type 3 study design was used, in which two areas were monitored for two
three-month periods, with street cleaning practiced in one area during the
first period and in the other area during the second period. Two areas were
selected after extensive review of candidates, including preliminary modeling
studies. Each study period was to last three months, and was designed to
provide enough data for subsequent statistical analysis.
Two monitoring sites were located in one study area and one in the other. A
fourth site, the Continuous Air Monitoring Station (CAMS.) operated by the
Oregon Department of Environmental Quality, was selected as a regional
trend site. Meteorological and traffic data were collected at this site on a
routine basis. Each monitoring site was equipped with a hi-vol sampler, a
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low-vol sampler, and a dichotomous sampler with a 2.5 micron size cutoff.
Sampling periods were 24 hours in duration and appear to have run from
midnight to midnight. The study was conducted during the dry season of May
through October.
Sampling and Analysis. In addition to collecting daily ambient air monitor-
ing and meteorological data within each study area, hourly and daily traffic
counts were recorded in each study area, as was vacuum sweeper performance
(daily sweeper logs were maintained by the operators). Road dust samples
were collected from curbs, medians, and traffic lanes to check the efficiency
of street sweeping and to provide a basis for comparing the chemical analysis
of filters collected from the monitoring sites.
Quality assurance procedures that |Were followed are not discussed in detail
in the report but are extensively referenced to sources including the
Quality Assurance Handbook published by the EPA Office of Research and
Development. No major problems associated with precision and repeatability
of instruments were reported. Some traffic count data was lost due to damage
to the counting equipment by vacuum sweepers.
Analysis of Results. For each monitoring site, the concentrations of TSP,
IP, and FP were calculated directly from the hi-vol, lo-vol, and dichotomous
filter weights. Filter samples were also analyzed by X-ray fluorescence for
17 elements. The "geologic component" was determined for-composite road dust
samples as well as for lo-vol and the coarse portion of the dichotomous
samples in an effort to correlate the two by a chemical mass balance tech-
nique. (The geologic component is that component associated with elements
common to soil.) Interferences due to industrial emissions would be high-
lighted by a large non-geologic component.
Two additional data sets were generated. The first was a set including
only "dry" days, defined as days greater than one since the last rainfall of
0.01 inch or more; the second was a set of all days in the period of June 25
to September 17.
The experimental values were normalized to the CAMS (background) value
by dividing the sample values by the CAMS values for the same period. Hence,
the results of each site were normalized to those of the regional trend
site. Data from each of the three sites were then subjected to a linear
regression analysis. '
Emission Factors and Control Efficiencies.
statistically significant effect ,on
sweeping. In other words, given the
differences in air quality between the two areas
variations in the generation of particulate matter
of the controls. It is possible that larger sample sizes
in statistically significant differences; however, because the number of
samples in all cases already exceeds 30 samples, it is more likely that,
given the conditions of the experiment, vacuum sweeping had no significant
None of the three sites showed a
particulate air quality from vacuum
number of samples used, any measured
can be attributed to random
rather than to the effect
may have resulted
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effect on particulate air quality. The geologic mass data suggest that, for
two of the sites, sweeping may actually increase the concentration of par-
ticulates in the ambient air.
Because the results of the study did not demonstrate a significant air
quality improvement from sweeping, the planned use of chemical mass balance
techniques to combine meteorologic and traffic variables to develop a
dispersion model capable of predicting the area wide effect of sweeping was
not conducted.
Generally speaking, the conclusions presented are well founded in the
results of the study. A pertinent, point is made that an earlier study citing
beneficial results from sweeping was based on sweeping the traveled areas of
the roadways in addition to the curb lanes; only the curb lanes were swept in
this study. Perhaps the reentrainment of dust from the travel lanes of paved
roads is a major source of nontraditional particulate emissions. Any
further research on vacuum sweeping should give attention to this area of
the road surface.
Optional Investigations. One of the optional investigations undertaken
in the Portland study involved elemental analysis of samples by X-ray
fluorescence. Although conducted primarily to support the chemical mass
balance approach, this analysis was useful in identifying interferences. For
example, geologic sources of particulates generally exhibit aluminum-to-sili-
con ratios of less than one. However, it was found that several samples from
one of the sites in an industrial area showed much higher ratios (as high as
30). Although the interfering source of aluminum particulate was not found,
all samples with ratios exceeding one Were deleted from the data base.
In order to be able to rule out reentrainment caused by the vacuum sweeper
itself as a significant source of particulate matter, a source sampling
method (Oregon Method 8) was used to test sweeper emissions under isokinetic
conditions. The results showed sweeper emissions to be on the order of 0.125
pound per hour, a relatively small amount.
Usefulness to State and Local Agencies. As a result of this study, state and
local officials should approach claims made for vacuum sweeping of paved
roads with caution. The results of this study firmly support the conclusion
that daily vacuum sweeping (at least as practiced in Portland for"this study)
does not significantly improve the particulate ambient air quality. An
important finding may be that no beneficial effect was observed from daily
vacuum sweeping of curb lanes, as opposed to travel lanes. Further study of
curb plus travel lanes is warranted.
Another important aspect of the study was the observation of an interference
and its subsequent removal from the results. The removal would have been
even more justifiable if the interfering source had been identified. The
measurement of the mineral content of collected samples, as practiced in
this study to reveal the interference, is highly desirable if not mandatory
for a study of this nature. This type of analysis should be weighed heavily
by state and local officials in the evaluation of demonstration studies
referenced by permit applicants.
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The investigation of the vacuum sweeper itself as a possible interference
represents an appropriate optional investigation. State and local officials
should scrutinize demonstration studies for this type of evaluation of
whether the control method itself represents a potential interference.
3.2 OTHER STUDIES
Several additional case studies are presented in lesser detail than the
foregoing major studies. The purpose is to further define the state of the
art for state and local agency officials.
i
3.2.1 Philadelphia, Pennsylvania \
\
The Philadelphia study [5] was ari early (1977) study of nontraditional
particulate emissions. A major portion of the study consisted of a liter-
ature search, an emission inventory, an analysis of previously collected
ambient TSP concentration data, and ;an analysis of field samples for several
metals and for TSP levels as a function of location, such as heavily traveled
urban streets and major construction: sites.
A receptor-oriented demonstration study of street washing in the downtown
area was quite limited and was intended to be only a minor portion of the
study. The application of controls \consisted of intensive water flushing of
all streets in a 10-block downtown >area for three consecutive days between
the hours of 7:00 AM and 6:30 PM. TSP levels were measured by hi-vol samp-
lers, recorded, and plotted for the ^periods before, during, and after flush-
ing. Traffic volume in the study area was also measured during this period.
Because the control period was onl^ three days, and because no attempt was
made to statistically remove other independent variables, the results of this
demonstration study were not verifiable. The tentative conclusion reached
was that street flushing under these conditions actually increased the TSP
concentration immediately after flushing. In analyzing this apparently
anomalous result, the researchers statistically compared TSP levels with
traffic volume, and found a strong correlation between the two. The re-
searchers speculated that the street flushing program was not effective
because the violent flushing of traffic lanes toward curbs and the splashing
of the as-yet undrained water by vehicles essentially redistribute previously
concentrated particles and, after 'drying, the particles may become reen-
trained.
Because this study was conducted several years ago, guidelines for its design
and conduct were not available. Therefore, this control technology can not
be evaluated unless further studies are undertaken and reinforced with
complete statistical analysis.
3.2.2 Bangor, Maine
This study [6], conducted for the City of Bangor, examined the effects of
vacuum sweeping of urban streets on ambient TSP concentrations during the
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period 1980 to 1983. The study made use of existing daily TSP measurements
determined by two hi-vol samples located in the downtown business district
and presumably operated by the city. The data spanned four street-sweeping
seasons (March through October of each year), the first two years represent-
ing the uncontrolled period. When the sweeping program was initiated, data
were collected for the following two-year period. A total of 223 data points
were available for the uncontrolled period, and 569 for the controlled
period.
The study report concludes that the vacuum sweeping program resulted in a
reduction in ambient TSP concentrations of 20 percent, and that the. statis-
tical analysis of the data supports this conclusion. However, it is diffi-
cult to evaluate this analysis because statistical parameters such as
standard deviations are not presented. Furthermore, it does not appear that
a statistical analysis of the independent variables was conducted to explain
differences in air quality during the two periods. Independent variables
such as meteorological conditions or construction activity may have accounted
for some of the difference in TSP concentrations for the two data sets.
3.2.3 Kansas City, Kansas
The Kansas City study [7] was conducted to determine the effectiveness of
twice-weekly sweeping and flushing of paved streets in an industrial area.
The study was receptor-oriented, measuring ambient concentrations of TSP
only. Measurements were made before and after controls were implemented in a
single downtown area. A Type 1 design was used because an "identical" test
area could not be found. Hence, the study was subject to greater possible
uncertainties than one using a Type 2 or 3 design. The study concluded that,
given the parameters of the experiment, there was no statistically signifi-
cant reduction in TSP concentrations in the area due to regular cleaning of
the streets. A multiple regression analysis revealed that the four indepen-
dent variables thought to have a major influence on TSP concentration had, in
fact, a relatively minor influence and that many other variables were in-
volved.
3.2.4 Lincoln, Nebraska
The Lincoln study [8] was conducted by the Lincoln-Lancaster County Health
Department. This was a receptor-oriented study in which concentrations of
TSP and IP were measured before and after application of liquid calcium
chloride to unpaved gravel and crushed rock roads. Calcium chloride is a
soluble crystalline salt that is applied as an aqueous solution for dust
control. A line source formula was then used to convert the measured
ambient concentrations into emissions on a mass per-vehicle-mile basis. A
single application of calcium chloride was not found to be effective for
TSP, but to be effective in reducing the concentration of IP by 70 to 80
percent (this reduction decayed to below 50 percent after about two-and-a-half
weeks). However, a 65 to 80 percent reduction in TSP; concentrations was
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found when applications to the unpaved roads were repeated at three to four
week intervals. The study appears to have been -a well-designed Type 1 study
in which independent variables not of interest "we re properly removed by
statistical analysis. Furthermore, the conclusions appear to be backed by an
adequate statistical analysis of the results.
3.2.5 Clark County, Nevada !
i
i
The Clark County study [9] was 'conducted by the Clark County Department
of Health. This study had three major-objectives:
o To estimate the relative^ost-effectiveness of magnesium chloride
and Coherex for dust control (magnesium chloride is a relatively
soluble crystalline compound employed as an 'aqueous solution;
Coherex is a petroleum resin used diluted with water)
o To study the effectiveness of alternative housing- construction
practices in reducing ambient particulate levels
i
o To study the effectiveness of emulsified asphalt on road shoulders
in reducing ambient particulate levels.
All portions of the study were rec;eptor-oriented and measured only TSP. The
chemical dust suppression and housing construction experiments were Type 2
designs, and the road shoulder experiment was a Type 1 design. Magnesium
chloride was found to be significantly less expensive to apply than Coherex;
however, no information was provided concerning the effectiveness of the
suppressants. The effectiveness of the unspecified alternative construction
practices could not be determined because the two study areas were too close
to one another. The effectiveness' of the road shoulder technique could not
be determined because of proximity,of the study area to construction activi-
ties. .
3.2.6 Erie County, New York
The Erie County study [10] was conducted by the Erie County Division of
Environmental Control to assess the effectiveness of several dust control
strategies in an industrial area. [Three techniques were assessed: watering
of storage piles (actually, notation of the effect of rainfall), oiling of
unpaved roads and-parking lots, and regular vacuum" "sweeping of paved roads.
TSP was the pollutant monitored in this receptor-oriented study. Several
hi-vol samplers were located throughout the study area, with at least one
sampler located at each specific test site. The study presented great
potential for interference among experiments, as they were all located
relatively 'Close to one another. The following conclusions were offered
concerning the control efficiencies of the methods tested:
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0
0
0
0
Watering storage piles no conclusion possible
Oiling unpaved roads . 40 to 60 percent reduction in TSP
Oiling parking-lots -- 40 to 70 percent reduction in TSP
Vacuum sweeping paved roads -.- 40 to 60 percent reduction in TSP.
Several factors cast doubt on the reliability of these conclusions. First,
each test consisted of only, a few measurements (generally three to seven).
It does not appear that a rigorous statistical analysis of test results was
conducted. Also, while the .possibilities for.interference among test areas
were numerous, the investigation did not seek to quantify the extent of this
interference. Finally, the long-term reduction in the effectiveness of
oiling was not addressed.
3.2.7 Allegheny County, Pennsylvania
An exhaustive study of nontraditional particulate emissions at U.S. Steel's
Allegheny County steel plants [11] was conducted as part of a consent
decree with EPA. A number of control methods were tested by surface sampling
of road dust as well as by the exposure profile technique. Exposure profil-
ing is a technique employing isokinetic sampling of several points across -a
dust "plume" cross section. Statistical analysis was -performed on both of
these source-oriented results to obtain control efficiencies. Measurements
were made of FP, IP and JSP. ..-
A control efficiency of 90 to 95 percent was given for control of unpaved
roads where the control of paving the road and following with daily vacuum-
ing. Applying Coherex to unpaved roads also achieved 90 to 95 percent
control in the short term. The effectiveness of a single application of
Coherex decreased after approximately 2,0 days; on the other hand, its
effectiveness was found to be cumulative with successive applications.
However, Coherex is considered to be relatively expensive. For paved roads,
the control efficiencies were as follows: 80 to 85 percent for daily vacuum-
ing, and 60 to 70 percent for twice-weekly vacuuming of moderately dusted
roads,; "---
roads.
and 40 to 50 percent for, twice-daily vacuuming of heavily-dusted
The general elements of the study design were essentially fixed by the
consent decree; Jiowever, the specific aspects of .the-design appear to have
been well formulated arid executed., Of particular usefulness are the develop-
ment of emission factor equations (through multiple linear regression analy-
sis) for the various .control techniques .tested, and the comparison of the
emission factors calculate^ from these equations with those calculated from
the experimental data.
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3.2.8 The Road Carpet Study ;
The Road Carpet Study [12] was performed for EPA's Industrial Environmental
Research Laboratory (IERL). The study assessed the effectiveness of a fabric
"road carpet" to control emissions from unpaved haul roads. Two Type 2
design tests were conducted using controlled and uncontrolled contiguous road
segments. The roads consisted of ;a crushed marble road at a western U.S.
site and a crushed shale road in the eastern U.S. Both tests employed hi-vol
samplers and hi-vols equipped with size-selective inlets to measure the
ambient concentration of TSP and IP. The results for individual tests of
control efficiency were as follows:
Control Efficiency
(percent)
Road type
Ma rbl e
Shale
Regiori
West'
East'
TSP
30-70
50-55
IP
30-50
65-75
A significant decay in the control effectiveness from these values over
several months was also noted. The study apparently did not employ extensive
statistical analysis to further analyze these results. The conclusions must
therefore be tempered with the knowledge that relatively few tests were run
and many must have been of short duration. (During one period, four tests
were run in one day.) Further testing with a thorough statistical analysis
of results is warranted before employing the results of this study.
3.2.9 The Iron and Steel Plant Studjies
i
Two studies of several iron and steel plants have been conducted for EPA's
IERL. The first steel plant study; [13] used exposure profiling (a source-
oriented technique) to measure the effectiveness of several control methods
for open sources of dust. For each! experiment in this study, a single area
was tested both in the presence and> absence of controls. The study concen-
trated more on the decay of control] effectiveness over time than on a sta-
tistical proof of the initial effectiveness of each measure. The researchers
apparently reasoned that the methods had been previously established as
effective, at least over the short term. Hence, the purpose of the study was
to demonstrate the change in effectiveness over time. The parameters meas-
ured were FP, IP, and TSP; the results may therefore be useful for comparison
with a future PM-10 regulation.
The treatment of unpaved roads with Coherex was found to be over 90 percent
effective in the short term, with a slow decay over time. The efficiency of
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treatment with water alone decayed from almost 100 percent to 60 percent in
only five hours. The efficiency of both vacuum sweeping and water flushing
of paved roads was found to decay rapidly from about 50 percent, while for
flushing with broom sweeping the efficiency decayed rapidly from
mately 70 percent.
approxi-
The decays in effectiveness were not quantified or discussed explicitly
in the report, but they were obvious from the emission factors developed from
the exposure profiling results. Conclusions for control of coal storage
piles were tenuous at best due to numerous experimental difficulties, such as
interference from precipitation and the contamination of filters by particles
that were not airborne. The study appears to have been well designed and
conducted; however, future work should concentrate on repeated testing of the
decay in control effectiveness for a specific technique, with a thorough
statistical analysis of the results.
The second or extended evaluation study [14] was also conducted for the IERL.
The study was designed to provide further information on the effectiveness of
dust suppressants on unpaved roads. Exposure profiling was used to measure
emissions under controlled and uncontrolled conditions. The results were
expressed in terms of decay rates or lifetime of effectiveness, the latter
expressed in terms of the number of vehicle passes. Variations in vehicle
weight, number of wheels and vehicle speed were statistically removed by a
normalization procedure based on a previously developed algorithm relating
the emission factor to these three independent variables. Effectiveness
decay rates were determined by a regression analysis, and were plotted for
each control method. The PM-10 fraction was measured in addition to TSP, IP
and FP.
"Petro-Tac" (an emulsified asphalt) on an unpaved road was found to have
an effective lifetime of about 100,000 vehicle passes for the control of
TSP. Effective lifetime in this case was defined as the time required for the
effectiveness of the control to decay essentially to zero. The control
efficiency of spraying water was initially high but decayed at a rate of
about 8 percent per hour. For Coherex, the results indicated a life of 7,500
vehicle passes for a single application and 45,000 for a repeat application.
As with the earlier study of this type, the results are contingent upon the
formulations and application rates used.
The study appears to have been well designed and conducted. A significant
number of samples were taken, and the analysis of the data is comprehensive.
Results were reported for IP, FP and PM-10 as well as for TSP, and the
variations in decay as a function of particle size are discussed in detail.
The information on effective lifetimes perhaps would have been better pre-
sented as the time required to decay to 75 percent or 50 percent effective-
ness because, as a practical matter, a source would have to reapply the
controls long before the effectiveness had decayed to zero.
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Chapter 4
CONCLUSIONS
The Workbook: Demonstration Studies for Control of Nontraditional Particu-
late Sources contains explicit instructions for the design and execution of a
conclusive and cost-effective demonstration study of control technologies.
However, the studies reviewed here exhibited a variety of problems in study
design and also in execution which resulted either in no conclusions con-
cerning the control technologies tested or in conclusions that were difficult
to support and not broadly applicable. The following studies were conducted
appropriately without major deviations from good study procedures. These are
Portland, Oregon; Lincoln, Nebraska; Kansas City, Kansas; Allegheny County,
Pennsylvania; and the Iron and Steel Plant studies. However, the remaining
studies suffered from inadequate designs, in some cases because the Workbook
guidelines were not available. The following cautions and recommendations
are offered to both study designers and those who must evaluate studies,
particularly studies offered in support of bubble proposals or similar plans
for particulate compliance:
o The Workbook has been assessed and found to be an excellent
guidance document which, when carefully followed, will greatly
enhance the likelihood of success of a demonstration study.
o A proper demonstration study is expensive to design and conduct;
however, a study that is not done properly will produce results
that cannot be applied in the field. Therefore, there must be a
firm commitment to a complete and proper study and effective
coordination and management of the study throughout.
o A demonstration study must be extremely well designed in order
to produce usable results; furthermore, the execution of the
study must rigorously follow the design. Cost-cutting ideas for
fewer monitors, less frequent application of controls and so
forth must be avoided so as not to invalidate the results and the
subsequent statistical analysis.
o In order to be applicable in the field, results from a demonstra-
tion study must be statistically significant. The study design,
therefore, must ensure that the statistical analysis selected is
correct for the type of study and that a sufficient number of
samples are taken. Careful coordination and control of the
control/no control arrangements of the study are also required.
-27-
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REFERENCES
1. Workbook: Demonstration Studies for Control of Nontraditional Partic-
ipate Sources. Contract No. 68-02-2535, Work Assignment No. 15. For
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Control Programs Operations Branch, March 1981.
2. Denver Demonstration Study'. PEDCo Environmental,
297337. For Colorado Division of Air Pollution
October 1981.
5.
8.
9.
10.
11.
Inc. Contract No. C
Control, Denver CO,
3. Kinsey, John Scott, Midwest Research Institute, and
Engineering, Inc. Study of Construction Related
Minnesota Pollution Control Agency, Roseville,
Jirik, Alan J., ETA
Dust Control. For
MN, December 1982.
4. Portland Road Dust Demonstration Project. Seton, Johnson, and Odell,
Inc. For City of Portland, OR, Department of Public Works, July 1983.
Record, Frank A., and Bradway, Robert M., GCA Technology Division.
Philadelphia Particulate Study. Contract No. 68-02-2345. For U.S.
Environmental Protection Agency, Region III, Air Programs Branch,
Philadelphia, PA, June 1978.
Hewitt, T.R., Sirrine Environmental Consultants, Inc. The Effectiveness
of Street Sweeping for Reducing Particulate Matter Background Concentra-
tions, Research Triangle Park, NC, 1981.
Study of Street Cleaning Impact on Particulate Levels in Kansas City,
Kansas. PEDCo Environmental, Inc. Contract No. 68-02-2535. For U.S.
Environmental Protection Agency, Region VII, Kansas City, MO, April
X z/O X
Walsh, Gary L., Lincoln-Lancaster County Health Department. Control of
Fugitive Dust From Unpaved Roads Using Liquid Calcium Chloride. For the
U.S. Environmental Protection Agency, October 1979.
1980 Annual Report on Status
Valley. Clark County Health
Las Vegas, Nevada, July 1981.
of Air Pollution Control in the Las Vegas
District, Air Pollution Control Division,
Demonstration of Fugitive Dust Control Effectiveness on Selected Open
Dust Sources in South Buffalo, NY. County of Erie, Department of
Environment and Planning, 1981.
Roffman, Amiram, et al, Energy Impact Associates. A Study of Control-
ling Fugitive Dust Emissions from Non-traditional Sources of the United
States Steel Corporation Facilities in Allegheny County, Pennsylvania.
Prepared for United States Steel Corporation, December 1981.
-29-
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12. Tackett, K,M>,, Blackwood, T.R., and Hedley, W.H., Monsanto Research
Corporation. Evaluation of Road Carpet for Control of Fugitive Emis-
sions From Unpaved Roads. Contract No. 68-02-3107. For U.S. Environ-
mental Protection Agency, Industrial Environmental Research Laboratory,
Research Triangle Park, NC, October 1980.
13. Cuscino, Thomas, Jr., Muleski; Gregory E., and Cowherd, Chatten, Jr.,
Midwest Research Institute. Iron and Steel Plant Open Source Fugitive
Emission Control Evaluation. Contract No. 68-02-3177, Assignment No. 4.
For U.S. Environmental Protection Agency, Industrial Environmental
Research Laboratory, Research Triangle Park, NC, August 1983.
14. Muleski, Gregory F., Cuscino,iThomas, Jr., and Cowherd, Chatten, Jr.,
Midwest Research Institute. Extended Evaluation of Unpaved Road Dust
Suppresants in the Iron and Steel Industry. Contract No. 68-02-3177,
Task 14. For U.S. Environmental Protection Agency, Industrial Environ-
mental Research Laboratory, Research Triangle Park, NC, February 1984.
-30-
U.S. GOVERNMENT PRINTING OFFICE: 1985-559-111/10762
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