EPA-450/2-92-004
FUGITIVE DUST BACKGROUND DOCUMENT
AND TECHNICAL INFORMATION DOCUMENT FOR
BEST AVAILABLE CONTROL MEASURES
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
September 1992
-------
Disclaimer
This document reflects the latest information that the
Environmental Protection Agency (EPA) has obtained on measures
for control of fugitive dust. As additional information becomes
available, the document will be updated, as appropriate. Mention
of trade names or commercial products is not intended to
constitute endorsement or recommendation for use.
Copies
Copies of this document are available through the Library
Services Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; or, for a fee, from
the National Technical Information Services, 5285 Port Royal
Road, Springfield, Virginia 22161.
ii September 1992
-------
CONTENTS
Disclaimer ii
Contents iii
Figures v
Tables vi
1.0 Introduction 1-1
1.1 Purpose of Document 1-1
1.2 Statutory Background 1-1
1.3 Document Organization. . 1-6
2.0 Sources and Pollutant Emissions 2-1
2.1 Paved roads 2-2
2.2 Unpaved roads 2-11
2.3 Storage piles 2-15
2.4 Construction/demolition 2-26
2.5 Open area wind erosion 2-34
2.6 Agricultural tilling 2-40
3.0 Emission Control Techniques 3-1
3.1 Paved roads 3-1
3.2 Unpaved roads 3-14
3.3 Storage piles .3-24
3.4 Construction/demolition 3-33
3.5 Hind erosion of open areas 3-42
3.6 Agriculture 3-49
4.0 Environmental Analysis of BACH 4-1
4.1 Comparison of baseline to post-BACM PM-10
emissions 4-2
4.2 Cross media impacts 4-17
iii September 1992
-------
CONTENTS (continued)
5.0 Control Cost Analysis Methodology 5-1
5.1 Estimating annualized cost 5-1
5.2 Estimating emission reduction 5-12
5.3 Model unit examples 5-12
6.0 Operating Permits 6-1
6.1 Paved roads 6-1
6.2 Unpaved roads 6-7
6.3 Storage piles 6-8
6.4 Construction/demolition ... 6-10
6.5 Wind erosion . 6-21
6.6 Agricultural tilling ,. . . 6-24
6.7 Opacity measurement 6-25
7.0 References 7-1
iv September 1992
-------
LIST OF FIGURES
Number Page
2-1 Field procedure for determination of surface aggregate
size distribution mode 2-20
2-2 Relationship of threshold friction velocity to size
distribution mode ..... 2-22
2-3 Increase in threshold friction velocity with LC . . 2-37
2-4 Roughness heights for various surfaces 2-39
3-1 Watering control effectiveness for unpaved travel
surfaces 3-19
3-2 Average PM-10 control efficiency for chemical
suppressants 3-21
3-3 Decay in control efficiency of latex binder applied to
coal storage piles 3-28
3-4 Annual evaporation data 3-37
4-1 Proposed model unit—paved roads 4-7
4-2 Proposed model unit—unpaved roads 4-8
4-3 Proposed model unit—building demolition 4-11
4-4 Example PM-10 control plan for building demolition 4-13
4-5 Proposed model unit—storage piles 4-16
4-6 Proposed model unit-wind erosion of open areas . . 4-18
4-7 Proposed model unit-agricultural tilling 4-19
6-1 Possible quantitative format for public paved road
sources 6-3
6-2 Questionnaire for construction site personnel . . . 6-19
6-3 Example dust permit 6-20
6-4 Example regulation for water mining activities . . 6-23
September 1992
-------
LIST OF TABLES
Number Page
1-1 Available control measures for fugitive dust BACM . 1-10
2-1 Decision rule for paved road emission estimates . . . 2-7
2-2 Emissions increase (AE) by site traffic volume . . 2-31
2-3 Emissions increase (AE) by construction type . . . 2-31
3-1 Measured efficiency values for paved road controls . 3-2
3-2 Nonindustrial paved road dust sources and
preventive controls 3-4
3-3 Selection criteria for antiskid abrasives 3-8
3-4 Guidelines for chemical application rates 3-9
3-5 Control techniques for unpaved travel surfaces . . 3-15
3-6 Control techniques for storage piles 3-25
3-7 Summary of available control efficiency data for wind
fences/barriers 3-47
3-8 Estimated PM-10 efficiencies for agricultural
controls . 3-50
4-1 Paved road emissions potential 4-3
4-2 Measured efficiency values for paved road controls . 4-4
4-3 Estimated PM-10 emission control efficiencies .... 4-4
4-4 Example control program design for Coherex applied to
travel surfaces 4-9
5-1 Model paved road 5-15
5-2 Model unpaved road 5-17
5-3 Model open area 5-18
5-4 Model storage pile 5-21
5-5 Model agricultural tilling operation 5-23
5-6 Model construction/demolition activity 5-25
6-1 Example regulation 6-12
6-2 Methods for compliance determination 6-22
6-3 Summary of TVEE Method 1 requirements (Ml) .... 6-27
6-4 Summary of Ohio Draft Rule 3745-17-(03) (B) .... 6-31
vi September 1992
-------
SECTION 1.0
INTRODUCTION
1.1 PURPOSE OF THIS DOCUMENT *'
The purpose of this document is to provide technical
information on control of fugitive dust sources. It provides
background information that may be useful in determining
reasonably available control measures
-------
1.2 STATUTORY BACKGROUND
1.2.1 Designations
Section 107(d) of the Clean Air Act (Act), as amended in
1990, provides generally for the designation of areas of each
State as attainment, nonattainment or unclassifiable for each
pollutant for which there is a national ambient air quality
standard (NAAQS). Certain areas meeting the qualifications of
section 107(d)(4)(B) of the amended Act were designated
nonattainment for PM-10 by operation of law upon enactment of the
1990 Amendments to the Act (initial PM-10 nonattainment areas).
A Federal Register notice announcing all of the areas designated
nonattainment for PM-10 at enactment and classified as moderate
was published on March 15, 1991 (56 FR 11101). A follow-up
notice correcting some of these area designations was published
August 8, 1991 (56 FR 37654). The boundaries of the
nonattainment areas were formally codified in 40 CFR
Part 81, effective January 6, 1992 (56 FR 56694, November 6,
1991). All those areas of the country not designated
nonattainment for PM-10 at enactment were designated
unclassifiable [see section 107(d)(4)(B)(iii) of the amended
Act].
1.2.2 Classifications
Once an area is designated nonattainment, section 188
outlines the process for classification of the area. In
accordance with section 188(a), at the time of designation, all
PM-10 nonattainment areas are initially classified as moderate by
operation of law. A moderate area can subsequently be
reclassified as a serious nonattainment area under two general
conditions. First, EPA has general discretion under section
188(b)(l) to reclassify a moderate area as a serious area at any
time the Administrator of EPA determines the area cannot
practicably attain the NAAQS by the statutory attainment date for
moderate areas. Second, under section 188(b)(2) a moderate area
September 1992
1-2
-------
is reclassified as serious by operation of law after the
statutory attainment date has passed if the Administrator finds
that the area has not attained the NAAQS. The EPA must publish a
Federal Register notice identifying the areas that have failed to
attain and were reclassified, within 6 months following the
attainment date [see section 188(b)(2)(B)].
Section 188(b)(l)(A) mandates an accelerated schedule by
which EPA is to reclassify appropriate initial PM-10
nonattainment areas. The EPA proposed on November 21, 1991
(56 FR 58656) to reclassify 14 of the 70 initial moderate areas
as serious. The final decision to reclassify the areas proposed
will be based on the criteria utilized in the proposal, comments
received in response to the proposal and on information in the
moderate area SIP's that were due on November 15, 1991 for each
of the areas.
In the future, EPA anticipates that, generally, any proposal
to reclassify an initial PM-10 nonattainment area before the
attainment date will be based on the State's demonstration that
the NAAQS cannot practicably be attained in the area by December
31t 1994 [the statutory attainment date specified in section
188(c)(l) for initial PM-10 nonattainment areas].
In addition to EPA's general authority under section
188(b)(l) to reclassify as serious any area the Administrator
determines cannot practicably attain the PM-10 NAAQS by the
applicable date, for areas designated nonattainment for PM-10
subsequent to enactment of the 1990 Amendments, subparagraph (B)
of section 188(b)(l) mandates that appropriate areas are to be
reclassified as serious within 18 months after the required date
for the State's submission of a moderate area SIP.1 Taken
together with the statutory requirement that PM-10 SIP's are due
within 18 months after an area is designated nonattainment [see
directive does not restrict EPA's general authority
but simply specifies that it must be exercised, as appropriate,
in accordance with certain dates.
September 1992
1-3
-------
section I89(a)(2)(B)], the statute thus requires that EPA
reclassify appropriate moderate areas as serious within 3 years
of the nonattainment designation.
Any decision by EPA to reclassify such a future
nonattainment area as serious will be based on facts specific to
the nonattainment area at issue and will only be made after
providing notice in the Federal Register and an opportunity for
public comment on the basis for EPA's proposed decision.
1.2.3 Serious Area Attainment Dates
The amended Act specifies that the initial moderate
nonattainment areas (those designated nonattainment upon
enactment of the 1990 Amendments) reclassified to serious are to
attain the PM-10 NAAQS as expeditiously as practicable but no
later than December 31, 2001. Areas designated nonattainment
subsequent to enactment that are reclassified as serious must
attain the PM-10 NAAQS as expeditiously as practicable but not
later than the end of the tenth calendar year after the area's
designation as nonattainment [see section 188(c)(2)].
1.2.4 Key Serious^Area SIP Requirements
As discussed above, States must develop and submit SIP's
providing for the attainment of the PM-10 NAAQS for every area
designated nonattainment and classified as moderate or serious
for PM-10 under the amended Act. New revisions must be made to
the PM-10 SIP in accordance with section 189(b) of the amended
Act for areas that are reclassified as serious nonattainment
areas. First, provisions must be adopted to assure that BACM
(including BACT) will be implemented in the area [see section
189(b)(l)(B)]. Second, a demonstration (including air quality .
modeling) must be submitted showing that the plan will attain the
NAAQS either by the applicable attainment date or, if an
September 1992
1-4
-------
extension is granted under section 188 (e), by the most
expeditious alternative date practicable [see section
The SIP revisions to require the use of BACM must be
submitted to EPA within 18 months after an area is reclassified
as serious [see section 189(b)(2)]. The BACM are to be
implemented no later than 4 years after an area is reclassified
[see section 189(b) (1) (B) ] .
The serious area attainment demonstration required under
section 189(b)(l)(A) must be submitted to EPA within 4 years
after an area is reclassified based on a determination by EPA
that the area cannot practicably attain by the statutory deadline
for moderate areas. It is due within 18 months after an area is
reclassified for actually having failed to attain by the moderate
area attainment date [see section 189(b)(2)].
1.2.5 RACM and BACM Issuance
Section 190 of the amended Act requires EPA to issue
technical guidance for RACM and BACM no later than 18 months from
enactment of the 1990 Amendments to the Act for three PM-10
source categories: urban fugitive dust, residential wood
combustion, and prescribed silvicultural and agricultural
burning. In conjunction with publication of the "General
Preamble for Title I of the Clean Air Act Amendments of 1990,"
EPA discharged the section 190 requirement to issue RACM
technical guidance for each of these three source categories [57
FR 13541, April 16, 1992; 57 FR 18070, April 28, 1992]. The
General Preamble provides a policy for how to utilize the
available RACM technical guidance to develop area-specific RACM
strategies .
The issuance of this fugitive dust BACM technical guidance
document (and its residential wood combustion and prescribed
burning companion documents), together with EPA's previous
issuance of RACM technical guidance, wholly fulfills EPA's
September 1992
1-5
-------
statutory obligation to issue RACM and BACM technical guidance
for urban fugitive dust, residential wood combustion, and
prescribed silvicultural and agricultural burning under section
190 of the amended Act. Similar to the manner in which EPA
provided guidance on Act requirements applicable to moderate
PM-10 nonattainment areas in the General Preamble, including a
policy or how to utilize the RACM technical guidance documents,
the EPA is planning to provide guidance on Act requirements and
provisions applicable to serious PM-10 nonattainment areas,
including BACM, in an addendum to the General Preamble. [EPA
made a draft of the addendum available for public comment on July
16, 1992 (57 FR 31477).] The portion of the addendum that
addresses BACM provides a policy for how to utilize today's
fugitive dust BACM technical guidance (and companion technical
guidance for control of residential wood combustion and
prescribed burning) to develop area-specific BACM strategies.
1.3 DOCUMENT ORGANIZATION
1.3.1 BACM Approach
Since a moderate area with fugitive dust sources may be
reclassified to serious, RACM and BACM must be consistent to
allow for a new control measure to be mandated or appended
without loss of the efficiency of the first measure. The
measures described in this document as available for fugitive
dust BACM are more stringent than RACM, and therefore should
result in greater control efficiencies. When a fugitive dust
source has been controlled under a RACM strategy, the
implementation of BACM will generally involve additive measures
that consist of a more extensive application of fugitive dust
control measures imposed under RACM. For example, BACM for
unpaved roads may consist of more miles of road to be paved.
Preventive measures for control of fugitive dust, as
contrasted with mitigative controls, are preferred and
recommended in this document. The reduction of source extent and
the incorporation of process modifications or adjusted work
September 1992
1-6
-------
practices which reduce the amount of exposed dust-producing
material constitute preventive measures for control of fugitive
dust emissions. This would include, for example, the elimination
of mud/dirt carryout onto paved roads at construction and
demolition sites. On the other hand, mitigative measures involve
the periodic removal of dust-producing material. Examples of
mitigative measures include: cleanup of spillage on travel
surface (paved and unpaved) and cleanup of material spillage at
conveyor transfer points.
1.3.2 BACM Implementation
The strategy for implementing BACM should begin with an
analysis of the required PM-10 emissions reduction to achieve
attainment status. The emissions inventory is then used to rank
order categories of PM-10 emission sources. Each source
category, with its source extent and emission factor is then
evaluated for control measures that, cumulatively, will achieve
the target level of control. This iterative process continues
from the first ranked source down to the source providing the
final required emissions reduction increment. Source categories
that have been determined to be insignificant contributors to
nonattainment (i.e., de minimis) may not need additional control
beyond RACM. Examples of fugitive dust sources that may be
insignificant (even though the fugitive dust source category as
whole may be significant) include:
Disturbed ground surfaces of less than one (1) acre.
Construction/demolition activity with a floor plan of
less than 10,000 ft2 or with movement of less than 250
yd3 of dirt or rock.
Paved and unpaved driveways, public easements and
shared public access roads serving a maximum of 20
single-family residential dwellings.
Paved and unpaved roads with a road length of less than
1/2 mile or with 20 or less vehicle trips per day.
September 1992
1-7
-------
Storing and handling of material where total material
volume is less than 250 yd3 or where the total annual
throughput is less than 2000 tons.
The site-specific feasibility analysis of candidate BACM
includes technical and economic evaluations. These evaluations
can be modeled after those described under the model
unit/nonattainment area scenarios contained in this document.
This feasibility analysis should optimize the overall strategy
for achieving the required PM-10 emissions reduction for the
lowest cost of control.
Dust control plans should be prepared for each of the
identified sources to be controlled, recognizing that BACM
strategies described in this document require stringent control
application with good assurance of enforceability. These plans
may consist of flexible approaches and methods of dealing with
special situations. The final stage of implementing BACM
involves recordkeeping requirements and inspection schedules for
determination of compliance.
1.3.3 Document Contents
This document is structured in a manner similar to an
alternative control techniques document for PM-10 emissions from
fugitive dust sources. The source categories that are discussed
in this document include: paved roads, unpaved roads, storage
piles, wind erosion from open areas, construction/demolition, and
agriculture. This information is, of necessity, general in
nature and does not fully account for unique variations within a
source category. Consequently it will be necessary for control
agency personnel to conduct their own analysis of BACM for
fugitive dust sources based on this guidance and examples
contained in this document.
Table 1-1 identifies BACM candidates for each source
category based on information presented in this document. The
list of control measures offers some flexibility of choice based
on site-specific feasibility analysis.
September 1992
1-8
-------
This document is organized as follows:
Chapter 2 identifies and describes the fugitive sources
of PM-10 emissions and presents a model unit for each
source category.
Chapter 3 discusses applicable emission control
techniques that are representative of BACN along with
estimates of control efficiencies.
Chapter 4 discusses the environmental impacts that may
result from implementing BACM, focusing on the
reduction in PM-10 emissions.
Chapter 5 presents cost analysis procedures and
calculates costs for each of the model unit
applications.
Chapter 6 presents example operating permits for each
fugitive dust source category.
September 1992
1-9
-------
Table 1-1. AVAILABLE CONTROL MEASURES FOR FUGITIVE DUST BACH
Source category
Control action
Paved roads
Unpaved roads
Storage piles (transfer
operations)
Construction/demolition
Open area wind erosion
Agricultural tilling
Improvements in sanding/salting
applications
and materials
Truck covering
Prevention of track-on/wash-on:
Construction site
measures
Curb installation
Shoulder stabilization
Storm water drainage
Paving
Chemical stabilization
Surface improvement (graveling)
Vehicle speed reduction
Wet suppression
Paving permanent roads early in
project
Truck covering
Access apron construction and
cleaning
Watering of graveled travel
surfaces
Revegetation
Limitation of off-road vehicle
traffic
Land conservation practices under
Food Security Act
1-10
September 1992
-------
SECTION 2
SOURCES AND POLLUTANT EMISSIONS
This section addresses emission factors for fugitive dust
sources. In addition, the approach to model units for each
source category is presented. The emission factors are drawn
primarily from AP-42, EPA's Compilation of Air Pollutant Emission
Factors (USEPA, 1985).
In AP-42, the reliability of emission factors is indicated
by an overall emission factor rating ranging from A (excellent)
to E (poor):
A-Excellent. Developed only from A-rated test data taken
from many randomly chosen facilities in the industry population.
The source category is specific enough to minimize variability
within the source category population.
B—Above average. Developed only from A-rated test data from
a reasonable number of facilities. Although no specific bias is
evident, it is not clear if the facilities tested represent a
random sample of the industry. As in the A-rating, the source
category is specific enough to minimize variability within the
source category population.
C—Average. Developed only from A- and B-rated data from a
reasonable number of facilities. Although no specific bias is
evident, it is not clear if the facilities tested represent a
random sample of the industry. As in the A rating, the source
category is specific enough to minimize variability within the
source category population.
D—Below average. The emission factor was developed only
from A- and B-rated test data from a smaller number of
September 1992
2-1
-------
facilities, and there may be reason to suspect that these
facilities do not represent a random sample of the industry.
There also may be evidence of unexplained variability within the
source category population. Limitations on the use of the
emission factor are footnoted in the emission factor table.
E—Poor. The emission factor was developed from C- and
D-rated test data, and there may be reason to suspect that the
facilities tested do not represent a random sample of the
industry. There may be evidence of variability within the source
category population. Limitations on the use of these factors are
always footnoted.
Because the application of these factors is somewhat
subjective, the reasons for each rating are documented in the
background files maintained by the Office of Air
Quality Planning and Standards (OAQPS).
2.1 PAVED ROADS
Fugitive dust emissions occur whenever a vehicle travels
over a paved surface, such as public and industrial roads and
parking lots. These emissions originate mostly from material
previously deposited on the travel surface, although resuspension
of material from tires and undercarriages can be significant when
vehicles travel from unpaved to paved areas. In general,
emissions correlate with road surface material loading (measured
as mass of material per unit area). The dust emitted from the
surface is in turn replenished by other sources (e.g., pavement
wear, deposition of material from vehicles, deposition from other
nearby sources, carryout from surrounding unpaved areas;, and
litter). Because of the importance of the surface loading,
available control techniques either attempt to prevent material
from being deposited on the surface or to remove (from the travel
lanes) any material that has been deposited.
While the mechanisms of particle deposition and resuspension
are largely the same for public and industrial roads, there can
September 1992
2-2
-------
be major differences in surface loading characteristics, traffic
characteristics, and viable control options. Although public
roads generally tend to have lower surface loadings than
industrial roads, the fact that public roads have far greater
traffic volumes may result in a substantial contribution to the
measured air quality in certain areas. For public roads in
industrial areas that are heavily loaded and traveled by heavy
vehicles, better emission estimates would be obtained by treating
these roads as industrial roads. In an extreme case, a road or
parking lot may have such a high surface loading that the paved
surface is covered completely and is easily mistaken for an
unpaved road. In that event, use of a paved road emission factor
may actually result in a higher estimate than that obtained from
the unpaved road emission factor. If this is the case, the road
is better characterized as unpaved in nature for purposes of
emission estimation.
Prior to use of the information in this section, the reader
should formulate preliminary answers to the following questions:
1. What paved roads are heavily loaded and thus likely to
contribute a disproportionate share of emissions?
2. What sources are likely to contribute to these elevated
surface loadings? For example, heavy trucks may spill part of
their load onto public roads in industrial areas, or large
amounts of salt and sand may be applied during winter months.
3. Who is the responsible party for each source identified
in 2 above?
4. Can the carryout/deposition from each identified source
of surface loading be prevented, or must the affected roadway be
cleaned afterward?
As discussed above, the term "public" is used in this
document to denote not only ownership of the road but also its
surface and traffic characteristics. Roads in this class
generally are fairly lightly loaded, are used primarily by light-
duty vehicles, and usually have curbs and gutters. Examples are
September 1992
2-3
-------
streets in residential and commercial areas and major
thoroughfares (including freeways and arterials).
2.1.1 Estimation of Emissions
The current AP-42 PM-10 emission factor for urban paved
roads is (USEPA, 1985):
.e '•= 2..28 \.SL/. O.S.j0'8
-------
Several items should be noted. First, samples used to
develop Equation (2-2) are restricted to the eastern and
midwestern portions of the country. These can be considered
representative of most large urban areas of the United States.
Lower silt loadings have been measured in the Southwest. Once
again, the use of site-specific data is stressed.
As noted earlier, emission estimation for paved roads
depends upon the surface material and traffic characteristics.
In this document, the term "industrial" paved roads is used to
denote those roads with higher surface loadings and/or that are
traveled by heavier vehicles. Consequently, some publicly owned
roads are better characterized as industrial in terms of
emissions. Examples would include city streets in heavily
industrialized areas or areas of construction as well as paved
roads in industrial complexes.
The current AP-42 PM-10 emission factor for industrial paved
roads is (USEPA, 1985):
e — *5 *} A -f crT / •*! O ^ ^ • 3 /rr
A ^ \J \ 04*1 / • ,L, ^ / \ y
e = 0,77 (5l,/Q,35)a:3
(Ib/VKH
(2-3)
where: e = emission factor, in g/VKT or Ib/VMT
sL = surface silt loading, g/m2 (oz/yd2)
The above equation is rated "A" in AP-42.
Alternatively, AP-42 presents a single-valued emission
factor for use in lieu of Equation (2-3) for PM-10 emissions from
light-duty vehicles on heavily loaded industrial roads:
September 1992
2-5
-------
. e = 93 :(g/VKT) '
•'..' •'•'• ...••• •• .
,-e * 0.33
This single-valued emission factor is rated "C."
Although no hard and fast rules can be provided, Table 2-1
summarizes a recommended decision process for selecting
industrial paved road emission factors.
AP-42 presents a summary of silt loading values for
industrial paved roads associated with a variety of industries.
As is the case with all AP-42 Chapter 11.2 emission models, the
use of site-specific data is strongly recommended.
Road sanding results in substantial increases in paved road
silt loading above normal levels. After sand is applied to roads
to increase traction on snow and ice, vehicle traffic serves to
reentrain the particulate, particularly the silt fraction
deposited in active lanes. Some additional silt is formed by
grinding. Emissions are much greater under dry road conditions.
The mass of emissions reentrained by road traffic is related
to sand quantity and size distribution. The entire PM-10
fraction contained in the silt of the applied sand is assumed to
become airborne.
The estimated PM-10 emissions from road sanding are
calculated as follows (Cowherd et al., 1988):
e = 2,000 /,(s/100), ••-.'life/tori.of sand applied). :(.2-5J
where f is the proportion of PM-10 in the silt fraction of sand
(default fraction of 0.0026), and s is the silt content (percent)
of the sand (default of 0.35 percent), as measured by ASTM-C-136.
September 1992
2-6
-------
TABLE 2-1. DECISION RULE FOR PAVED ROAD EMISSION ESTIMATES
Silt loading Average vehicle
(sL), g/m2 weight (W), Mg Use model
sL < 2 W > 4 Equation (2-3)
sL < 2 W < 4 Equation (2-1)
SL > 2a W > 6 Equation (2-3)
2 < sL < 15 W < 6 Equation (2-3)
sL > 15a W < 6 Equation (2-4)
a For heavily loaded surfaces (i.e., sL > ~ 300 to 400 g/m2,
it is recommended that the resulting estimate be compared
to that from the unpaved road models (Section 3.0 of this
manual), and the smaller of the two values used.
September 1992
2-7
-------
2.1.2 Model Units
For most nonindustrial areas in which the use of BACM is
contemplated, paved roads probably will constitute the most
spatially extensive source category. Ideally, State and local
officials considering BACM for a given area would have at their
disposal a complete, spatially resolved paved road emissions
inventory. In this context, the term spatially resolved implies
an information base that includes:
1. Road segment lengths;
2. "Representative" silt loading values (mass/surface
area—g/m2); and
3. Average daily traffic (ADT)
for essentially all segments in a given paved road network.
From the above information, it is reasonably easy to
estimate PM-10 emissions for individual road segments. In turn,
one could define model units—high, medium, and low—based on
emissions intensity.
One road classification system that can be used in
estimating paved road emissions is the Federal Highway
Administration (FHWA) Functional Classification. The functional
system consists of principal arterials (for main traffic
movements), minor arterials (distributors), collectors, and local
roads and streets. In urban areas there are further functional
subdivisions of the arterial category. In rural areas, there are
further functional subdivisions of the collector category.
Characteristics of these categories are described by AASHTO
(1990). This system is summarized below.
FEDERAL HIGHWAY ADMINISTRATION
FUNCTIONAL CLASSIFICATIONS
Rural:
Interstate
Other principal arterial
September 1992
2-8
-------
Minor arterial
Major collector
Minor collector
Local
Urban:
Interstate
Other freeways and expressways
Other principal arterial
Minor arterial
Collectors
Local
This widely used system treats urban and rural areas
separately where urban is defined as an area with boundaries set
by the responsible State and local officials and having a
population of 5,000 or more; rural areas are those areas outside
of urban areas.
In examining this classification scheme, it is important to
recognize that road categories are based on the function-
character of service—that the roads are intended to provide. For
example, in the rural network, arterials (including interstates)
generally provide direct service between cities and larger towns,
which constitute a large proportion of the relatively longer
trips. In contrast, collectors serve small towns directly,
connecting them to the arterial network. These collectors take
or distribute traffic to the local roads which serve individual
farms or other rural land uses.
Other points that should be recognized are:
The FHWA classification is not directly tied to the
physical parameters that are most important to BACM
analyses—segment length and ADT. However, one would
expect a strong, although certainly not perfect,
positive correlation between functional class and ADT.
September 1992
2-9
-------
The principal advantage of the FHWA system is that it
is in widespread use. States routinely compile and
report traffic data that are relevant to the
determination of BACM, according to this system.
Given the above, the approach to application of BACM may be
structured to incorporate the FHWA system. It also is clear that
the structure must adopt the principles of preventive control-
prevention or at least minimization of mud/dirt source material
carried onto roadways. The concept of preventive controls can,
in part, be tied to access control.
For example, interstate highways are characterized by strict
access control—vehicles can enter or leave the road only at a
limited number of locations. In addition, these roads are
characterized by relatively wide, improved (asphalt) shoulders
and the use of appropriate vegetation for erosion control. The
net result is extremely low surface loadings for this type of
roadway. For this reason, despite high ADT, it can be argued
that interstates/expressways represent a relatively insignificant
source category, except in the case of sand/salt applications.
At the other end of the classification scheme—local roads—
one also could argue that these roads represent a minor source
category. In this case, access is essentially free; however, ADT
should generally be quite low. As a result, the dust-emitting
potential of these roads is relatively low. It also is important
to recognize that actually instituting BACM.for the local road
network may be impractical given the sheer number of individual
road segments contained within an urban area.
Accepting the above arguments—resulting in the
classification of interstate highways (and other limited access
roadways) and local roads as less important source categories-
restricts the application of BACM to arterial and collector
street categories. In typical urban functional systems, these
categories may constitute 20 percent to 35 percent of total road
mileage. In effect, it is for the arterial and collector street
September 1992
2-10
-------
categories that the elements of the spatially resolved inventory
(segment length, silt loading, ADT), and consideration of
adjacent land use, become critical.
2.2 UNPAVED ROADS
As is the case for paved roads, fugitive dust emissions
occur whenever a vehicle travels over an unpaved surface. Unlike
paved roads, however, the road itself is the source of the
emissions rather than any "surface loading." Within the various
categories of open dust sources in industrial settings, unpaved
travel surfaces have historically accounted for the greatest
share of particulate emissions. For example, unpaved travel
surfaces were estimated to account for roughly 70 percent of open
dust emissions in the iron and steel industry during the 1970's
(Cowherd et al., 1988).
Recognition of the importance of unpaved roads led naturally
to an interest in their control. During the 1980's, industry
paved many previously unpaved roads as part of emission control
programs. Nevertheless, the need for continued control of these
sources is apparent.
Travel surfaces may be unpaved for a variety of reasons.
Possibly the most common type of unpaved road is that found in
rural regions throughout the country. These roads may experience
only sporadic traffic which, taken with the often considerable
road length involved, makes paving impractical.
Some industrial roads are, by their nature, not suitable for
paving. These roads may be used by very heavy vehicles or may be
subject to considerable spillage from haul trucks. Haul roads
typically generate significant unpaved road emissions because of
the heavy weight of the haul trucks. Other roads may have poorly
constructed bases that make paving impractical. Because of the
additional maintenance costs associated with a paved road under
these service environments, emissions from these roads are
September 1992
2-11
-------
usually controlled by regular applications of water or chemical
dust suppressants.
In addition to roadways, many industries often contain
important unpaved travel areas. Examples include areas used for
truck parking, scraper traffic patterns related to
stockpile/reclaim activities in coal yards, compactor traffic
proximate to lifts at landfills, and truck travel related to open
storage of finished products (such as coil at steel plants).
These areas may often account for a substantial fraction of
traffic-generated emissions from individual plants. In addition,
these areas tend to be much more difficult to control than
stretches of roadway. For example, changing traffic patterns
make semipermanent controls impractical, and increased shear
forces from cornering vehicles may rapidly deteriorate chemically
stabilized surfaces.
2.2.1 Estimation of Emissions
As was the case for paved roads, unpaved roads may be
divided into the two classes of public and industrial. However,
for the purpose of estimating emissions, there is no need to
distinguish between the two, because the AP-42 emission factor
equation takes source characteristics (such as average vehicle
weight and road surface texture) into consideration (USEPA,
1985).
September 1952
2-12
-------
where: e = PM-10 emission factor in units stated
s = silt content of road surface material, percent
(ASTM-C-136)
S = mean vehicle speed, km/h (mi/h)
W = mean vehicle weight, Mg (ton)
w = mean number of wheels (dimensionless)
p = number of days with > 0.254 mm (0.01 in) of
precipitation per year
Using the scheme given in AP-42, the above equation is rated "A,"
when used within the tested ranges of correction parameter
values. As is the case with all AP-42 emission factors, the use
of site-specific data is strongly encouraged.
The number of wet days per year, p, for the geographical
area of interest should be determined from local climatic data.
Maps giving similar data on a monthly basis are available from
the National Climatic Center at Asheville, North Carolina.
It is important to note that for the purpose of estimating
annual or seasonal controlled emissions from unpaved roads,
average control efficiency values based on worst case
uncontrolled emissions levels [i.e., dry roads, p = 0 in Equation
(2-6)] are required. This is true simply because the AP-42
predictive emission factor equation for unpaved roads, which is
routinely used for inventorying purposes, is based on source
tests conducted under dry conditions. Extrapolation to annual
average uncontrolled emission estimates is accomplished by
assuming that emissions are occurring at the estimated rate on
days without measurable precipitation, and conversely are absent
on days with measurable precipitation. This assumption has not
been verified in a rigorous manner; however, experience with
hundreds of field tests indicate that it is a reasonable
assumption if the source operates on a fairly "continuous" basis.
September 1992
2-13
-------
2.2.2 Model Units
Many of the comments made concerning the paved road source
category are equally applicable to unpaved roads. In particular,
BACM for this source category is best considered in light of a
spatially resolved inventory that includes:
1. Road segment lengths and geographic locations.
2. Average daily traffic (ADT).
3. Representative silt content values (percent < 75 jimP).
4. Average vehicle characteristics—speed, weight, and
wheels.
Segment length and ADT are the most critical data elements
as they represent source extent—vehicle miles traveled (VMT).
If spatially resolved source extent information is available, one
could logically design model units—high, medium, and low—based
on this information.
Unlike the paved road case, there is no generally inclusive
alternative classification scheme that can be used to structure
BACM determinations for the unpaved road source category.
However, in a qualitative sense, one can use certain elements of
the FHWA system to roughly order road types. For example, based
on the presumption that functional arterials and collectors have
higher ADT than local roads, high-intensity unpaved roads could
be defined in terms of four existing FHWA categories.
I. Urban minor arterials.
2. Urban collectors.
3. Rural major collectors.
4. Rural minor collectors.
Following the same rationale, one could argue that a similar
hierarchy of local roads also exists. In other words, there is
some systematic (albeit unknown) relationship between the
function of local unpaved roads and their corresponding ADT. For
example, unpaved private driveways might be considered logically
as the lowest intensity or de minimis model unit as they see very
September 1992
2-14
-------
little ADT. Practically, this type of road would be a difficult,
if not impossible, source for which to establish and then enforce
BACM.
At the other end of the local system hierarchy might be the
relatively short stretches of unpaved roadway that serve as
access for subdivision development in unincorporated portions of
a given county. One could argue that some farm roads,
particularly for situations in which labor-intensive crops are
grown, constitute a relatively high-intensity local road source.
In a given jurisdiction, if these types of roadways can be
identified, then application of BACM probably would be feasible.
2.3 STORAGE PILES
Inherent in operations that use minerals in aggregate form
is the maintenance of outdoor storage piles. Storage piles are
usually left uncovered, partially because of the need for
frequent material transfer into or out of storage.
Dust emissions occur at several points in the storage cycle,
during material loading onto the pile, during disturbances by
strong wind currents, and during loadout from the pile. The
movement of trucks and loading equipment in the storage pile area
is also a substantial source of dust.
2.3.1 Estimation of Emissions
The quantity of dust emissions from aggregate storage
operations varies with the volume of aggregate passing through
the storage cycle. Also, emissions depend on correction
parameters that characterize the condition of a particular
storage pile: moisture content and proportion of aggregate
fines.
When freshly processed aggregate is loaded onto a storage
pile, the potential for dust emissions is at a maximum. Fines
September 1992
2-15
-------
are easily disaggregated and released to the atmosphere! upon
exposure to air currents from transfer operations or high winds.
As the aggregate weathers, however, potential for dust emissions
is greatly reduced. Moisture causes aggregation and cementation
of fines to the surfaces of larger particles.
Total dust emissions from aggregate storage piles are
contributions of several distinct source activities within the
storage cycle:
1. Loading of aggregate onto storage piles (batch or
continuous drop operations).
2. Equipment traffic in storage area.
3. Wind erosion of pile surfaces and ground areas around
piles.
4. Loadout of aggregate for shipment or for return to the
process stream (batch or continuous drop operations).
2.3.1.1 Materials Handling—
Adding aggregate material to a storage pile or removing it
usually involves dropping the material onto a receiving surface.
Truck dumping on the pile or loading out from the pile to a truck
with a front-end loader are examples of batch drop operations.
Adding material to the pile by a conveyor stacker is an example
of a continuous drop operation.
The following AP-42 equation is recommended for estimating
emissions from transfer operations (batch or continuous drop):
o.
. e * O.OOli i£J-— (ib/ton)
September 1992
2-16
-------
where: e = PM-10 emission factor, in units stated
U = mean wind speed, m/s (mph)
M = material moisture content, percent
Based on the criteria presented in AP-42, the above equation is
rated A, when used within the tested ranges of correction
parameter values.
2.3.1.2 Equipment Traffic—
For emissions from equipment traffic (trucks, front-end
loaders, dozers, etc.) traveling between or on piles, it is
recommended that the equations for vehicle traffic on unpaved
surfaces be used (see Section 2.2). For vehicle travel between
storage piles, the silt value(s) for the areas between the piles
(which may differ from the silt values for the stored materials)
should be used.
2.3.1.3 Wind Erosion—
Dust emissions may be generated by wind erosion of open
aggregate storage piles and exposed areas within an industrial
facility. These sources typically are characterized by
nonhomogeneous surfaces impregnated with nonerodible elements
(particles larger than approximately 1 cm in diameter). Field
testing of coal piles and other exposed materials using a
portable wind tunnel has shown that (a) threshold wind speeds
exceed 5 m/s (11 mph) at 15 cm above the surface of the pile or
10 m/s (22 mph) at 7 m above the surface of the pile, and (b)
particulate emission rates tend to decay rapidly (half life of a
few minutes) during an erosion event. In other words, these
aggregate material surfaces are characterized by finite
availability of erodible material (mass/area) referred to as the
erosion potential. Any natural crusting of the surface binds the
erodible material, thereby reducing the erosion potential.
September 1992
2-17
-------
2.3.1.3.1 Emissions and Correction Parameters—If typical
values for the threshold wind speed at 15 cm are corrected to a
typical wind sensor height (6-10 m), the resulting values exceed
the upper extremes of hourly mean wind speeds observed in most
areas of the country. In other words, mean atmospheric wind
speeds usually are not sufficient to sustain wind erosion from
aggregate material surfaces. However, wind gusts may quickly
deplete a substantial portion of the erosion potential.. Because
erosion potential has been found to increase rapidly with
increasing wind speed (above the threshold value), estimated
emissions should be related to the gusts of highest macjnitude.
The routinely measured meteorological variable which best
reflects the magnitude of wind gusts is the fastest mile. This
quantity represents the wind speed corresponding to the; whole
mile of wind movement that has passed by the l-mi contact
anemometer in the least amount of time. Daily measurements of
the fastest mile are presented in the monthly Local
Climatological Data (LCD) summaries available from the National
Climatic Center, Asheville, North Carolina. The duration of the
fastest mile, typically about 2 min (for a fastest mile of 30
mph), matches well with the half life of the erosion process,
which ranges between 1 and 4 min. It should be noted, however,
that instantaneous peak winds can significantly exceed the daily
fastest mile.
The wind speed profile in the surface boundary layer is
found to follow a logarithmic distribution:
where: u = wind speed, cm/s
u* = friction velocity, cm/s
z = height above test surface, cm
z = roughness height, cm
September 1992
2-18
-------
0.4 = von Karman's constant, dimensionless
The friction velocity (u*) is a measure of wind shear stress
on the erodible surface, as determined from the slope of the
logarithmic velocity profile. The roughness height (zo) is a
measure of the roughness of the exposed surface as determined
from the y-intercept of the logarithmic velocity profile, i.e.,
the height at which the wind speed is zero. A typical roughness
height for open terrain is 0.5 cm.
Emissions generated by wind erosion are also dependent on
the frequency of disturbance of the erodible surface because each
time that a surface is disturbed, its erosion potential is
restored. A disturbance is defined as an action which results in
the exposure of fresh surface material. On a storage pile, this
would occur whenever aggregate material is either added to or
removed from the old surface. A disturbance of an exposed area
may also result from the turning of surface material to a depth
exceeding the size of the largest pieces of material present.
2.3.1.3.2 Predictive Emission Factor Equation (USEPA,
1985)—The AP-42 emission factor for wind-generated particulate
emissions from mixtures of erodible and nonerodible surface
material subject to disturbance may be expressed in units of
g/m2-yr as follows:
N .'•':':'
e :- 0.5 £ • J?± (2-9)
1 •= '1 • ... x :.: .
where: e = PM-10 emission factor, g/m2
N = number of disturbances per year
P^ = erosion potential corresponding to the observed
(or probable) fastest mile of wind for the ith
period between disturbances, g/m2
September 1992
2-19
-------
In calculating emission factors, each area of an erodible
surface that is subject to a different frequency of disturbance
should be treated separately. For a surface disturbed daily, N =
365/yr, and for a surface disturbance once every 6 mo, N = 2/yr.
The erosion potential function for a dry, exposed surface
has the following form:
:P = 58 (ir* *• u£)2 + 25 fu* ~ Ut) : : :. ::.
• •••••-•••]••- • ,f; "•>••'. - ..:••• .••.;:;;.•;•'...";••;';.•••.(2-io)•
P = 0 fbr-'tr* s-:iit . • :" " V ':'•'•"' ':' '••'•• • •''•••
where: u* = friction velocity (m/s)
u^. = threshold friction velocity (m/s)
Because of the nonlinear form of the erosion potential function,
each erosion event must be treated separately.
Equations 2-9 and 2-10 apply only to dry, exposed materials
with limited erosion potential. The resulting calculation is
valid only for a time period as long or longer than the period
between disturbances. Calculated emissions represent
intermittent events and should not be input directly into
dispersion models that assume steady state emission rates.
For uncrusted surfaces, the threshold friction velocity is
best estimated from the dry aggregate structure of the soil. A
simple hand sieving test of surface soil (adapted from a
laboratory procedure published by W. S. Chepil, 1952) can be used
to determine the mode of the surface aggregate size distribution
by inspection of relative sieve catch amounts (Figure 2-1). The
threshold friction velocity for erosion can be determined from
the mode of the aggregate size distribution, as described by
Gillette (1980) (Figure 2-2). Threshold friction velocities for
September 1992
2-20
-------
1. Prepare a nest of sieves with the following openings: 4 mm,
2 mm, 1 van, 0.5 nun, 0.25 mm. Place a collector pan below
the bottom sieve (0.25-mm opening).
2. Collect a sample representing the surface layer of loose
particles (approximately 1 cm in depth for an uncrusted
surface), removing any rocks larger than about 1 cm in
average physical diameter. The area to be sampled should
not be less than 30 cm x 30 cm.
3. Pour the sample into the top sieve (4-mm opening)j and place
a lid on the top.
4. Rotate the covered sieve/pan unit by hand using broad
sweeping arm motions in the horizontal plane. Complete 20
rotations at a speed just necessary to achieve some relative
horizontal motion between the sieve and the particles.
5. Inspect the relative quantities of catch within each sieve
and determine where the mode in the aggregate size
distribution lies, i.e., between the opening size of the
sieve with the largest catch and the opening size of the
next largest sieve.
Source: Adapted from a laboratory procedure published by W. s.
Chepil (1952).
Figure 2-1. Field Procedure for the Determination of Surface
Aggregate Size Distribution Mode.
September 1992
2-21
-------
•5" 1000
CO
£
o
O
o
0)
O
uZ
6
S
4
a
•= 100
10
0.1
2 3456789 2 3 45. 6789
1 10
22 3 456789
100
Aggregate Size Distribution Mode (mm)
Figure 2-2.
Relationship of Threshold Friction Velocity to Size
Distribution Mode.
2-22
September 1992
-------
several surface types have been determined by field measurements
with a portable wind tunnel (Gillette, 1980; Muleski, 1985;
Nickling and Gillies, 1986).
The friction velocity (u*) is best related to the fastest
mile of wind in the area for the periods between pile
disturbances. As discussed above, the fastest mile may be
obtained from the monthly LCD summaries for the nearest reporting
weather station that is representative of the site in question,
available from the National Climatic Center. These summaries
report actual fastest mile values for each day of a given month.
Because the erosion potential is a highly nonlinear function of
the fastest mile, mean values of the fastest mile are
inappropriate. The anemometer heights of reporting
weather stations are found in Changery (1978), and should be
corrected to a 10-m reference height using Equation 2-8.
To convert the fastest mile of wind (u+) from a reference
anemometer height of 10 m to the equivalent friction velocity
(u*), the logarithmic wind speed profile may be used to yield the
following equation:
:0,053 .Uo' ••! . . .,(2-11);
where: u = friction velocity (m/s)
u"^0 = fastest mile of reference anemometer for period
between disturbances (m/s)
This assumes a typical roughness height of 0.5 cm for open
terrain. Equation 2-11 is restricted to large relatively flat
piles or exposed areas with little penetration into the surface
wind layer.
If the pile significantly penetrates the surface wind layer
(i.e., with a height-to-base ratio exceeding 0.2), it is
necessary to divide the pile area into subareas representing
September 1992
2-23
-------
different degrees of exposure to wind. The results of physical
modeling as described below show that the frontal face of an
elevated pile is exposed to wind speeds of the same order as the
approaching wind speed at the top of the pile.
For two representative pile shapes (conical pile and oval
pile with flat-top, 37 degree side slope), the ratios of surface
wind speed (ug) to approach wind speed (ur) have been derived
from physical modeling in a laboratory wind tunnel (Studer and
Arya, 1988). The results are shown in AP-42, Section 11.2.7,
corresponding to an actual pile height of 11 m, a reference
(upwind) anemometer height of 10 m, and a pile surface roughness
height (zo) of 0.5 cm. The measured surface winds correspond to
a height of 25 cm above the surface. The profiles of us/ur can
be used to estimate the surface friction velocity distribution
around similarly shaped piles, using the procedure described in
AP-42.
The recommended emission factor equation presented above
assumes that all of the erosion potential corresponding to the
fastest mile of wind is lost during the period between
disturbances. Because the fastest mile event typically lasts
only about 2 min, which corresponds roughly to the half-life for
the decay of actual erosion potential, it could be argued that
the emission factor overestimates particulate emissions.
However, there are other aspects of the wind erosion process
which offset this apparent conservatism:
1. The fastest mile event contains instantaneous peak
winds which substantially exceed the mean value for that event.
2. Whenever the fastest mile event occurs, there are
usually a number of periods of slightly lower mean wind speed
which contain peak gusts of the same order as the fastest mile
wind speed.
Of greater concern is the likelihood of overprediction of
wind erosion emissions in the case of surfaces disturbed
infrequently in comparison to the rate of crust formation.
September 1992
2-24
-------
2.3.1.3.3 Wind Emissions Front Continuously Active Piles—
For emissions from wind erosion of active (frequently disturbed)
storage piles, the following AP-42 emission factor equation is
recommended for estimating total suspended particulate (TSP)
emissions:
••;;'•:. .;•••:••.::::. '.'• •'.•'•'••'•' C2-12)
_ .. .,-..,.».
>^'i» 0.25 mm (0.01 in.) of
precipitation per year
f = percentage of time that the unobstructed wind
speed exceeds 5.4 m/s (12 mph) at the mean pile
height
The fraction of TSP which is PM-10 is estimated at 0.5 and is
consistent with the PM-10/TSP ratios for materials handling.
The coefficient in Equation (2-12) is taken from Cowherd et
al. (1974), based on sampling of emissions from a sand and gravel
storage pile area during periods when transfer and maintenance
equipment was not operating. The factor from Cowherd et al.
(1974), expressed in mass per unit area per day, is more reliable
than the factor expressed in mass per unit mass of material
placed in storage, for reasons stated in that report. Note that
the coefficient has been halved to adjust for the estimate that
the wind speed through the emission layer at the test site was
one half of the value measured above the top of the piles. The
other terms in this equation were added to correct for silt,
September 1992
2-25
-------
precipitation, and frequency of high winds, as discussed in Bonn
et al. (1978).
Worst case emissions from storage pile areas occur under dry
windy conditions. Worst case emissions from materials handling
(batch and continuous drop) operations may be calculated by
substituting into Equation (2-7) appropriate values for aggregate
material moisture content and for anticipated wind speeds during
the worst case averaging period, usually 24 h. The treatment of
dry conditions for vehicle traffic (Equation 2-6) and for wind
erosion (Equation 2-12), centering around parameter p = 0,
follows the methodology described for unpaved roads (Section
2.2). Also, a separate set of nonclimatic correction parameters
and source extent values corresponding to higher than normal
storage pile activity may be justified for the worst case
averaging period.
2.3.2 Model Units
In general, it is expected that most storage piles in urban
areas would either be part of a permitted industrial operation
(such as a quarry) or be associated with other sources discussed
in this report (antiskid material stockpiles, earthen material
piles at construction sites, etc.). It is anticipated that
virtually all other storage piles (such as might be found at
landscaping contractors) would be below the de minimis threshold.
2.4 CONSTRUCTION/DEMOLITION
2.4.1 Estimation of Emissions
At present, the only emission factor available.in AP-42 is
1.2 tons/acre/month (related to particles < ~ 30-/um Stokes'
diameter) for an entire construction site. No factor has been
published for demolition in AP-42. However, PM-10 emission
September 1992
2-26
-------
factors have been developed for construction site preparation
using test data from a study conducted in Minnesota for topsoil
removal, earthmoving (cut-and-fill), and truck haulage operations
(Kinsey et al., 1983). For these operations, the PM-10 emission
factors based on the level of vehicle activity (i.e., vehicle
kilometers traveled or VKT) occurring on-site are (Grelinger et
al., 1988):
Topsoil removal: 5.7 kg/VKT for pan scrapers
Earthmoving: 1.2 kg/VKT for pan scrapers
Truck haulage: 2.8 kg/VKT for haul trucks
PM-10 emissions due to materials handling and wind erosion
of exposed areas can be calculated using the emission factors for
storage piles (section 2.3) and agricultural wind erosion
(section 2.5), respectively.
2.4.1.1 Demolition Emissions—
For demolition sites, the operations involved in demolishing
and removing structures from a site are:
• Mechanical or explosive dismemberment
Debris loading
Onsite truck traffic
Pushing (dozing) operations
2.4.1.2 Dismemberment—
Since no emission factor data are available for blasting or
wrecking a building, the operation is addressed through the use
of the revised AP-42 materials handling equation:
September 1992
2-27
-------
0 . 0005.6 v * < kg / Mg > ( 2-13 )
x-4
If}.
where: eD = PM-10 emission factor in kg/Mg of material
u = mean wind speed in m/s (default = 2.2 m/s)
M = material moisture content in percent (default =
2 percent)
ED = 0.00056 kg/Mg (with default parameters)
The above factor can be modified for waste tonnage related
to structural floor space where 1 m2 of floor space represents
0.45 Mg of waste material (0.046 ton/ft2) (Grelinger et al.,
1988). The revised emission factor related to structural floor
space (using default parameters) can be obtained by:
: eD * 0.00056 kg/Mg *0.4S
TO (2-14)
0.00025 kg/m2 of .structural floor space "•
2.4.1.3 Debris Loading—
The emission factor for debris loading is based on two tests
of the filling of trucks with crushed limestone using a front-end
loader which is part of the test basis for the batch drop
eguation in AP-42, Section 11.2.3. The resulting PM-10 emission
factor for debris loading is (Grelinger et al., 1988):
September 1992
2-28
-------
Or - k CO.029> :kg/Mg • 0,45 ^? .
m2 (2-15)
0.0046
where 0.029 kg/Mg is the average measured TSP emission factor and
k is the particle size multiplier (0.35 for PM-10).
2.4.1.4 Onsite Truck Traffic—
Emissions from onsite truck traffic is estimated from the
existing AP-42 unpaved road equation:
where: eT = PM-10 emission factor in kg/VKT
s = silt content in percent (default = 12 percent)
S = truck speed in km/h (default = 16 km/h)
W = truck weight in Mg (default = 20 Mg)
w = number of truck wheels (default = 10 wheels)
p = number of days with measurable precipitation
(default = 0 days)
and eT =1.3 kg/VKT (with default values)
The above factor is converted from kg/VKT to kg/m2 of structural
floor space by:
• • Ef =
0.40 km
23 m3 waste
1 ip5 waste „
4 a3 volume
7 .€5 m3 vblxtfne . j.3Jcg
O.S36 m'. floor space . v&r
-0.052 kg/iff
2-17)
2.4.1.5 Pushing Operations—
For pushing (bulldozer) operations, the AP-42 emission
factor equation for overburden removal at Western surface coal
mines can be used. Although the AP-42 equation actually relates
to particulate 15 fan, it can be converted to 10 pm by a
correction factor. The AP-42 dozer equation is:
September 1992
2-29
-------
where: ep - PM-10 emission rate in kg/hr
s = silt content of surface material in percent
(default = 6.9 percent) (ASTM-C-136)
M = moisture content of surface material in percent
(default = 7.9 percent)
0.75 = PM-10/PM-15 conversion factor
and Ep =0.34 kg/hr (with default parameters)
2.4.1.6 Mud/Dirt Carryout Emissions—
Mud and dirt carryout from construction and demolition sites
often accounts for a temporary but substantial increase in paved
road emissions. The increase in emissions on paved roads due to
mud/dirt carryout has been developed based on surface loading
measurements at eight sites (Englehart and Kinsey, 1983).
Tables 2-2 and 2-3 provide these emission factors in terms of
g/vehicle pass which represent PM-10 generated over and above the
"background" for the paved road sampled. Table 2-2 expresses the
emission factors according to the volume of traffic entering and
leaving the site, whereas Table 2-3 expresses the same data
according to type of construction. Either table may be used by
the analyst.
2.4.2 Model Units
Construction represents a fugitive dust source category for
which permitting and inspection systems are clearly in place.
Furthermore, each site is associated with a party who could be
held responsible for dust control. Finally, even though the area
may be large, the spatial extent of a construction site is well
defined. Because of these factors, an effective emission
September 1992
2-30
-------
TABLE 2-2. EMISSIONS INCREASE (AE) BY SITE TRAFFIC VOLUME"
Sites with > 25
vehicles/day
Sites with < 25
vehicles/day
Particle Std.
size devia-
fraqtion Mean, tion, a Range
x
Std.
devia-
Mean, x tion, a Range
< ~ 30
< 10 fJOR
< 2.5 jm
52
13
5.1
28
6.7
2.6
15-80
4.4-
20
1.7-
7.8
19
5.5
2.2
7
2
0.
.8
.3
88
14-28
4.2-
8.1
1.6-
3.2
a AE expressed in g/vehicle pass.
b Aerodynamic diameter.
TABLE 2-3. EMISSIONS INCREASE (AE) BY CONSTRUCTION TYPE"
Commercial
Particle
size
fraction13
< ~ 30
Urn
< 10 nm
< 2.5 /im
Mean,
X
65
16
6.3
Std.
devia-
tion, a
39
9.3
3.6
Range
15-
110
4.2-
25
1.6-
9.7
Residential
Mean,
X
39
10
3.9
Std.
devia-
tion, a
22
5.4
2.1
Range
10-72
2.8-19
1.1-
7.3
• AE expressed in g/vehicle pass.
b Aerodynamic diameter.
2-31
September 1992
-------
inventory can be more readily developed for construction dust
than for the other source categories. In addition, these factors
make permit requirements involving dust control more tractable
than for the other source categories.
The following discussion uses three sequential "phases" to
provide a model unit framework in which emissions from
construction activities are conveniently identified and
estimated. Each phase considers "unit" dust emitting activities
involving similar equipment and, hence, relatively similar
emission estimation procedures. The three phases are:
Phase I. Debris Removal. during which debris from any man-
made structures or natural obstructions is removed from the site.
Thus, this phase includes the removal of demolition debris from
implosion or mechanical dismemberment (e.g., "headache" ball) of
buildings as well as from the blasting of rock formations and
from excavation. Principal emission categories are: material
loadout, vehicle travel on paved or unpaved surfaces, and
trackout of mud/dirt onto adjacent public streets.
Phase II. Site Preparation, during which the ground surface
of the site is brought to final or near-final grade. Thus, this
phase includes on-site cut/fill operations (e.g., scrapers,
dozers) as well as the transport of cut material off-site and the
receipt of "imported" fill materials. Principal emission
categories are: scraping and bulldozing, material loadout,
vehicle travel on paved or unpaved surfaces, and trackout of
mud/dirt onto adjacent public streets.
Phase III. Construction, which includes the other major
construction activities, including flatwork, structural and
reinforcing steel, exterior operations, interior finishing, and
landscaping. Although major source categories can be identified,
it is generally difficult to accurately estimate daily source
extents, etc. That is, in contrast to Phase I and Phase II
activities which can be relatively accurately scheduled and
September 1992
2-32
-------
estimated, Phase III is highly dependent on the receipt of
materials and there are many simultaneous operations.
Three points should be noted. First, this division of the
overall construction process into three phases is certainly
arbitrary in that other phases could have been defined or certain
operations could be moved from one phase to another. For
example, another scheme might classify removal of blasted rock as
"site preparation" rather than "debris removal." The scheme
presented here merely provides a series of sequential phases
involving similar equipment and emission estimation procedures.
Second, all three phases need not be present at an individual
construction site. Finally, only emissions due to debris removal
operations, rather than the demolition process itself, will be
considered in the following discussion.
Compared to continuously emitting (point) emission sources,
it is more difficult to envision model units for construction-
related dust sources. Because construction dust is inherently
short-term at one location, cost-effective control depends more
upon available materials, environmental setting, and phasing than
upon available control technology. In other words, because dust
needs to be controlled for only a short period of time at one
location, the installation of long-term controls is usually not
warranted unless that control is already planned as part of the
construction project. Rather, the selection of appropriate
control measures depends upon issues such as:
What materials (e.g., waterf salts) are available to use in
controlling dust? As an example, consider vehicular traffic on
unpaved surfaces. For most roads, chemical stabilization is far
more cost-effective than regular road watering. However, it is
often difficult to justify the more expensive chemical treatment
of construction site travel routes which have very short lives.
What constraints does surrounding land use place on the
types of controls that could be used? Control techniques
available for use in heavily developed areas with traffic
September 1992
2-33
-------
congestion can be expected to differ substantially from those
used in largely undeveloped areas.
What changes to the construction schedule could be made to
reduce dust emissions? Construction projects, such as industrial
parks and residential development, usually involve permanent
roads that will eventually be paved. In those instances, early
paving represents an effective and economical (because the roads
have already been budgeted) control measure.
2.5 OPEN AREA WIND EROSION
Dust emissions may be generated by wind erosion of open
agricultural land or exposed ground areas on public property or
within an industrial facility. With regard to estimating
particulate emissions from wind erosion of exposed surface
material, site inspection can be used to determine the potential
for continuous wind erosion. The two basic requirements for wind
erosion are that the surface be dry and exposed to the wind. For
example, if the site lies in a swampy area or is covered by
grass, the potential for wind erosion is virtually nil. If, on
the other hand, the vegetative cover is not continuous over the
exposed surface, then the plants are considered to be nonerodible
elements which absorb a fraction of the wind stress that
otherwise acts to suspend the intervening soil.
For estimating emissions from wind erosion, either of two
emission factor equations are recommended depending on the
erodibility of the surface material. Based on the site survey,
the exposed surface must be placed in one of two erodibility
classes described below. The division between these classes is
best defined in terms of the threshold wind speed for the onset
of wind erosion.
Nonhomogeneous surfaces impregnated with nonerodible
elements (stones, clumps of vegetation, etc.) are characterized
by the finite availability ("limited reservoir11) of erodible
September 1992
2-34
-------
material. Such surfaces have high threshold wind speeds for wind
erosion, and particulate emission rates tend to decay rapidly
during an erosion event. On the other hand, bare surfaces of
finely divided material such as sandy agricultural soil are
characterized by an "unlimited reservoir" of erodible surface
particles.
Based on analysis of wind erosion research, the dividing
line for the two erodibility classes is a threshold friction
velocity of about 50 cm/s. This division is based on the
observation that highly erodible surfaces, usually corresponding
to sandy surface soils that are fairly deep, have threshold
friction velocities below 50 cm/s. Surfaces with friction
velocities larger than 50 cm/s tend to be composed of aggregates
too large to be eroded mixed in with a small amount of erodible
material or having crusts that are resistant to erosion. The
cutoff friction velocity of 50 cm/s corresponds to an ambient
wind speed of about 7 m/s (15 mph), measured at a height of about
7 m.
Crusted surfaces are regarded as having a "limited
reservoir" of erodible particles. Crust thickness and strength
should be examined during the site inspection by testing with a
pocket knife. If the crust is more than 0.6 cm thick and not
easily crumbled between the fingers (modulus of rupture 1 bar),
then the soil may be considered nonerodible. If the crust
thickness is less than 0.6 cm or is easily crumbled, then the
surface should be treated as having a limited reservoir of
erodible particles. If a crust is found beneath a loose deposit,
the amount of this loose deposit, which constitutes the limited
erosion reservoir, should be carefully estimated.
For uncrusted surfaces, the threshold friction velocity is
best estimated from the dry aggregate structure of the soil. A
simple hand-sieving test of surface soil is highly desirable to
determine the mode of the surface aggregate size distribution by
inspection of relative sieve catch amounts, following the
September 1992
2-35
-------
procedure specified in Figure 2-1. The threshold friction
velocity for erosion can be determined from the mode of the
aggregate size distribution, as shown in Figure 2-2.
A more approximate basis for determining threshold friction
velocity would be based on hand sieving with just one sieve, but
otherwise follows the procedure specified in Figure 2-1. Based
on the relationship developed by Bisal and Ferguson (1970), if
more than 60 percent of the soil passes a 1-mm sieve, the
"unlimited reservoir" model will apply; if not, the "limited
reservoir" model will apply. This relationship has been verified
by Gillette (1980) on desert soils.
If the soil contains nonerodible elements which are too
large to include in the sieving (i.e., greater than about 1 cm in
diameter), the effect of these elements must be taken into
account by increasing the threshold friction velocity (U^.*).
Marshall (1971) has employed wind tunnel studies to quantify the
increase in the threshold velocity for differing kinds of
nonerodible elements. His results are depicted in terms of a
graph of the rate of corrected to uncorrected friction velocity
versus Lc (Figure 2-3), where Lc is the ratio of the silhouette
area of the roughness elements to the total area of the bare
loose soil. The silhouette area of a nonerodible element is the
projected frontal area normal to the wind direction. A value for
Lc is obtained by marking off a 1-m x 1-m surface area and
determining the fraction of area, as viewed from directly
overhead, that is occupied by nonerodible elements. Then the
overhead area should be corrected to the equivalent frontal area;
for example, if a spherical nonerodible element is half-embedded
in the surface, the frontal area is one-half of the overhead
area. Although it is difficult to estimate LC for values below
0.05, the correction to friction velocity becomes less sensitive
to the estimated value of Lc.
The difficulty in estimating LC also increases for small
nonerodible elements. However, because small nonerodible
September 1992
2-36
-------
ev
\
\
in v n N
Figure 2-3. Increase in Threshold Friction Velocity with L_.
2-37
September 199
-------
elements are more likely to be evenly distributed over the
surface, it is usually acceptable to examine a smaller surface
area, e.g., 30 cm x 30 cm.
Once again, loose sandy soils fall into the high erodibility
("unlimited reservoir") classification. These soils do not
promote crust formation, and show only a brief effect of moisture
addition by rainfall. On the other hand, compacted soils with a
tendency for crust formation fall into the low ("limited
reservoir") erodibility group. Clay content in soil, which tends
to promote crust formation, is evident from crack formation upon
drying.
The roughness height, ZQI which is related to the size and
spacing of surface roughness elements, is needed to convert the
friction velocity to the equivalent wind speed at the typical
weather station sensor height of 7 m above the surface.
Figure 2-4 depicts the roughness height scale for various
conditions of ground cover (Cowherd and Guenther, 1976).
2.5.1 Estimation of Emissions
2.5.1.1 "Limited" Erosion Potential—
In the case of surfaces characterized by a "limited
reservoir" of credible particles, the emission estimation
procedure is identical to that presented in Section 2.2.1.3.2 for
a "flat" pile.
2.5.1.2 "Unlimited" Erosion Potential—
For a surface characterized by an "unlimited reservoir" of
erodible particles, particulate emission rates are relatively
time independent at a given wind speed. The technology currently
used for predicting agricultural wind erosion in the United
States is based on variations of the Wind Erosion Equation
(Skidmore and Woodruff, 1968; Woodruff and Siddoway, 1965). This
prediction system uses erosion loss estimates that are integrated
September 1992
2-38
-------
HI
High Rise Buildings*
(30+ Roors)
Suburban
Medium Buildings <
(Institutional)
Suburban
Residential Dwellings.
Wheat Field'
Plowed Reid-
2o (cm)
1000
Natural Snow •
^•^•^fe
1— »
1-,-fc
—600—
—400—
—200—
100
^-80.0—
—60.0—
—40.0—
—20.0—
10.0
—8.0—
—6,0—
—4.0—
—2.0 —
1.0
—0.8—
—0.6—
— 0.4 —
— 0.2 —
0.1
^
-
-
Urban Area
Woodland Forest
Grassland
Figure 2-4. Roughness Heights for Various Surfaces.
2-39
September 19<
-------
over large fields and long-time scales to produce average annual
values.
2.5.2 Model Units
Compared to mechanical disturbances (e.g., vehicular
traffic), emissions from open area wind erosion may be a
relatively minor contributor to the total PM-10 emissions in most
urban areas. As such, this entire source category could be
considered as de minimis except for areas with dry climate and
high wind speeds. The proposed model unit for open areas can be
based on the total acres exposed and the number of disturbances
per year. Wind erosion calculations would then be performed to
determine the overall contribution to the total PM-10 emissions
inventory.
2.6 AGRICULTURAL TILLING
Fugitive dust from agricultural operations occasionally
contributes to the ambient PM-10 levels in many rural counties
and in some urban areas. Such agricultural operations include
(a) plowing, (b) disking, (c) fertilizing, (d) applying
herbicides and insecticides, (e) bedding, (f) flattening and
firming beds, (g) planting, (h) cultivating, and (i) harvesting.
These operations can be generically classified as soil
preparation, soil maintenance, and crop harvesting operations.
This section will focus on emissions from agricultural tilling
operations that are designed to (a) create the desired soil
structure for the crop seed bed and (b) to eradicate weeds.
September 1992
2-40
-------
2.6.1 Estimation of Emissions
2.6.1.1 Tilling—
The mechanical tilling of agricultural land injects dust
particles into the atmosphere as the soil is loosened or turned
under by plowing, disking, harrowing, etc. AP-42 presents a
predictive emission factor equation for the estimation of dust
emissions from agricultural tilling.
e * 1.1
-------
e~.kaXK.ClJV . (2-2O)
where: e = PM-10 wind erosion losses of tilled fields,
tons/acre/yr
k = 0.5, the estimated fraction of TSP which is
PM-10
a = portion of total wind erosion losses that would be
measured as total suspended particulate, estimated
to be 0.025
I = soil erodibility, tons/acre/yr
K = surface roughness factor, dimensionless
C = climatic factor, dimensionless
L' = unsheltered field width factor, dimensionless
V = vegetative cover factor, dimensionless
As an aid in understanding the mechanics of this equation,
"I" may be thought of as the basic erodibility of a flat, very
large, bare field in a climate highly conducive to wind erosion
(i.e., high wind speeds and temperature with little
precipitation) and K, C, L', and V as reduction factors for a
ridged surface, a climate less conducive to wind erosion,
smaller-sized fields, and vegetative cover, respectively.
2.6.2 Model Unit
The PM-10 emissions from agricultural tilling are both crop-
specific and directly related to the total acreage in production.
For example, the quantity of emissions from the production of
nuts is quite different than that associated with row crops on a
per acre basis. Therefore, a classification scheme based on type
of crop and acreage in production is proposed.
A suitable model unit for tilling operations can be based on
acreage of a field tilled five times a year and classified as
"highly erodible" under the Food Security Act (FSA) of 1985.
September 1992
2-42
-------
This model unit will be used in section 4 to demonstrate PM-10
control effectiveness of placing agricultural land into the
Conservation Reserve program of the FSA.
September 1992
2-43
-------
SECTION 3
EMISSION CONTROL TECHNIQUES
3.1 PAVED ROADS
Available control methods are largely designed either to
prevent deposition of material on the roadway surface or to
remove material which has been deposited in the driving lanes.
Measurement-based efficiency values for control methods are
presented in Table 3-1. Note that all values in this table are
for mitigative measures applied to industrial paved roads.
In terms of public paved road dust control, only very
limited field measurement data are available. Estimated
PM-10 control efficiencies of approximately 35 percent were
developed by applying Eguation (2-1) to measurements before and
immediately after road cleaning (Duncan et al., 1984). Note that
these estimates should be considered upper bounds on efficiencies
obtained in practice because no redeposition after cleaning is
considered. Note also that these estimated emission control
efficiencies for urban roads compare fairly well with
measurements at industrial roads. No airborne mass emission
measurements quantifying control efficiency of public paved road
dust control were found in the published literature.
In general terms, one would expect that demonstrated control
techniques applied to industrial paved roads could also be
applied to public roads. One important point to note, however,
is that the effectiveness of mitigative measures generally
September 1992
3-1
-------
TABLE 3-1.
MEASURED EFFICIENCY VALUES FOR PAVED ROAD
CONTROLS3
Method
Cited
efficiency
Comments
Vacuum sweeping
Water flushing
Water flushing
followed by sweeping
0-58% Field emission
measurement (PM-15)
12,000-cfm blower"
46% Reference 7, based on
field measurement of
30 fjm particulate
emissions
69-0.231 vc'd Field measurement of
PM-15 emissions"
96-0.263 vc'd Field measurement of
PM-15 emissions"
All results based on measurements of air emissions from
industrial paved roads. Broom sweeping measurements
presented in Section 2.3.2.1 (Cowherd and Kinsey, 1986).
PM-10 control efficiency can be assumed to be the same as
that tested.
Water applied at 0.48 gal/yd2.
Eguation yields efficiency in percent, V = number of
vehicle passes since application.
3-2
September 1992
-------
decreases as the surface loadings decrease (i.e., it would be
less effective to clean the interstate highway surfaces rather
than collector street surfaces).
Because mitigative measures are less effective for public
paved roads, an EPA urban dust policy stresses the importance of
long-term preventive measures as BACM candidates, especially in
instances where no dominant or localized source of paved road
surface loading can be identified. Examples of nonlocalized
sources of paved road surface loading would include: (a) unpaved
shoulders adjacent to paved roads, (b) erosion due to storm water
runoff, and (c) spillage from passing trucks. Corresponding
examples of preventive measures include: (1) installing curbs,
paving shoulders, or painting lines near the edge of the
pavement; (2) channeling storm water runoff or using vegetation
to stabilize surrounding areas; and (3) requiring trucks to be
covered and to maintain freeboard (i.e., distance between top of
the load and top of truck bed sides).
In instances where the source of loading can be easily
identified (e.g., salt or sand spread during snow or ice storms)
or the effects are localized (e.g., near the entrance to
construction sites or unpaved parking lots), either preventive or
mitigative measures could be prescribed. Table 3-2 summarizes
Agency guidance on nonindustrial paved road preventive controls.
There are few measured efficiency values for any of the
preventive measures presented in Table 3-2.
Almost all measured control efficiency values for paved
roads are based on data from industrial roads. Consequently, the
information presented earlier in Table 3-1 is more applicable to
this class of road. Mitigative measures may be more practical
for industrial plant roads because: (1) the responsible party is
known; (2) the roads may be subject to considerable spillage and
carryout from unpaved areas; and (3) all affected roads are
relatively close proximity, thus allowing a more efficient use of
cleaning equipment. Preventive measures, of course, can be used
September 1992
3-3
-------
TABLE 3-2.
NONINDUSTRIAL PAVED ROAD DUST SOURCES AND
PREVENTIVE CONTROLS
Source of deposit on road
Recommended controls
Sanding/salt
Spills from haul trucks
Construction carryout and
entrainment
Vehicle entrainment from
unpaved adjacent areas
Erosion from stormwater
washing onto streets
Wind erosion from adjacent
areas
Other
Make more effective use
of abrasives through
planning, uniform
spreading, etc.
Improve the abrasive
material through
specifications limiting
the amount of fines and
material hardness, etc.
Rapid cleanup after
streets become clear and
dry
Require trucks to be
covered
Require freeboard between
load and top of hopper
Wet material being hauled
Clean vehicles before
entering road
Pave access road near
site exit
Semicontinuous cleanup of
exit
Pave/stabilize portion of
unpaved areas nearest to
paved road
Storm water control
Vegetative stabilization
Rapid cleanup after event
Wind breaks
Vegetative stabilization
or chemical sealing of
ground
Pave/treat parking ares,
driveways, shoulders
Limit traffic or other
use that disturbs soil
surface
Case-by-case
determination
3-4
September 1992
-------
in conjunction with plant street cleaning programs and prevention
is the preferred approach for reducing emissions from city
streets in industrialized areas with many potential sources of
paved road dust. As before, the lack of efficiency values for
preventive measures remains an important gap and reguires further
investigation.
3.1.1 Preventive Measures
These types of control measures prevent the deposition of
additional materials on a paved surface area. As a result, it is
difficult to estimate their control effectiveness. Instead of
assigning control effectiveness values for preventive measures,
regulatory personnel may choose to require all responsible
parties (e.g., general contractors, street departments spreading
salt and sand, businesses/homeowners with unpaved parking lots
and driveways) to either submit control plans or agree to agency-
supplied programs. Note that freguent watering of unpaved access
areas should be discouraged (if possible) because that practice
may compound mud/dirt carryout problems.
As early as 1971, EPA recommended reasonable mud/dirt
carryout precautions including:
Watering or use of suppressants at
construction/demolition, road grading, and land
clearing sites.
Prompt removal of materials deposited upon paved
roadways.
Covering of open trucks transporting material likely to
become airborne.
While most States have adapted many of EPA's recommendations
to their own regulations, the vast number and spatial
distribution of potential mud/dirt carryout points, as well as
the large number of potentially responsible parties, make
enforcement very difficult to plan and administer. Conseguently,
September 1992
3-5
-------
smaller jurisdictive areas (such as cities and counties) should
be used in monitoring carryout enforcement. Note that these
local agencies include several besides those involved in air
pollution per se. For example, building permits may be used to
require carryout controls with building inspectors enforcing the
regulations. Finally, it is clear that some agreement with the
local public works department would be necessary to implement
modifications in street salting and sanding procedures or to
ensure prompt cleanup.
3.1.1.1 Sanding for Snow and Ice—
After winter snow and ice control programs, the heavy
springtime street loadings found in certain areas of the country
are known to adversely affect ambient PM-10 concentrations. For
example, data collected in Montana indicate that road sanding may
produce early silt loadings 5 to 6 times higher than the baseline
loading (MRI, 1983). Because that increase corresponds to
roughly a fourfold increase in the emission level, it is clear
that residual surface loadings represent an important source
potentially requiring control. As determined by Kinsey (1991):
1. Antiskid materials are frequently applied at loadings
well above recommended levels because of public perception that
effectiveness is proportional to the visible amount of surface
loading.
2. Excess silt loadings (and thus PM-10 emissions)
associated with antiskid materials result primarily from
overapplication and noncompliance with recommended fines and
durability specifications for antiskid abrasives.
As indicated in Table 3-2, appropriate controls may include:
(a) cleanup as soon as practical (vacuum sweeping or flushing
followed by broom sweeping), (b) the use of improved materials,
and (c) improvements in planning or application methods.
September 1992
3-6
-------
3.1.1.1.1 Improved Antiskid Materials—Some municipalities
have experimented by supplementing or replacing their usual
snow/ice control materials with other harder and/or coarser
materials. Because the choice of usual materials is based upon
local availability (salt, sand, cinders) and price, it is clear
that changes in materials applied will generally result in higher
costs. However, the use of antiskid materials with either a
lower initial silt content or greater resistance to forming silt-
size particles will result in lower road surface silt loadings.
Only limited field measurements comparing resultant silt contents
and no measurements of silt loading values have been identified;
conseguently, it is not possible at this time to accurately
estimate the control efficiency afforded by use of improved
materials. Kinsey (1991) has formulated selection criteria for
antiskid materials that will result in lower silt generation, as
shown in Table 3-3.
3.1.1.1.2 Application of Sand—Improvements in planning and
application technigues limit the amount of antiskid material
applied to roads in an area. AASHTO guidelines for application
are shown in Table 3-4. As was the case with improved materials,
no field data are known to exist. However, an adeguate estimate
of areawide control efficiency can be obtained by: (a) comparing
the amounts of material applied; (b) assuming that both
applications are equally subject to formation of fines, removal,
etc.; (c) assuming that both resultant silt loadings are
substantially greater than the "baseline" (i.e., prewinter)
value; and (d) using Eguation (2-1). For example, if a
community, through better planning, uses 30 percent less antiskid
material, then the resultant silt loadings may be expected to be
30 percent lower. Use of Eguation (2-1) would then indicate an
effective PM-10 control efficiency of 24.8 percent. Note that if
assumption (c) above does not hold, the estimated control
efficiency should be viewed only as an upper bound. The
September 1992
3-7
-------
TABLE 3-3. SELECTION CRITERIA FOR ANTISKID ABRASIVES
Acceptable Unaccept-
materialsa able
materials
b
Measurement
parameter
Modified Los Angeles
abrasion loss
Initial silt
content0
Vickers hardness
Particle shape index
Units
Weight %
Weight %
kg/mm2
Dimen-
sionless
Range of
values
0.9 - 4
0.02 -
0.03
500 -
1,200
6.3 - 15
Mean Range
of
values
3 7-17
0.1 4-9
1,00 400 -
0 1,000
10 6.5 -
13
M
e
a
n
1
1
6
8
0
0
9
a Based on data for cluster C4.
k Based on data for cluster C5.
c This parameter is coupled to LA abrasion loss and thus
included in the material selection criteria.
3-8
September 1992
-------
TABLE 3-4. GUIDELINES FOR CHEMICAL APPLICATION RATES
(AASHTO,1976)
OJ
1
U)
September 1992
Weather conditions
Pavement
Temperature conditions Precipitation
30°F and Wet Snow
above
Sleet or freezing
rain
25°-30°F Wet Snow or sleet
Freezing rain
20°-25°F Wet Snow or sleet
Freezing rain
15°-20°F Dry Dry snow
Wet Wet snow or sleet
Below 15°F Dry Dry snow
Application rate (pounds of material per mile
Low- and high-
speed
multilane divided
300 salt
200 salt
Initial at 400 salt;
repeat at 200 salt
Initial at 300 salt;
repeat at 200 salt
Initial at 500 salt;
repeat at 250 salt
Initial at 400 salt;
repeat at 300 salt
Plow
500 of 3:1 salt/
calcium chloride
Plow
Two- and three-
lane primary
300 salt
200 salt
initial at 400
salt;
repeat at 200
salt
Initial at 300
salt;
repeat at 200
salt
Initial at 500
salt;
repeat at 250
salt
Initial at 400
salt;
repeat at 300
salt
Plow
500 of 3:1 salt/
calcium
chloride
Plow
Two-lane
secondary
300 salt
200 salt
Initial at 400
salt;
repeat at 200
salt
Initial at 300
salt;
repeat at 200
salt
1,200 of 5:1
sand/
salt; repeat
same
Plow
1,200 of 5:1
sand/
salt
Plow
of two-lane road or two lanes divided)
Instructions
• Wait at least 0.5 h before plowing
• Reapply as necessary
• Wait at least 0.5 h before plowing;
* repeat
• Repeat as necessary
• Wait about 0.75 h before plowing;
repeat
• Repeat as necessary
• Treat hazardous areas with 1,200 of
20:1 sand/salt
• Wait about 1 h before plowing;
continue plowing until storm ends;
then repeat application
• Treat hazardous are with 1 ,200 of 20: 1
sand/salt
•
-------
application of less material may be achieved by applying sand
only to intersections, hills, and curves on roads with low ADT,
as safety permits. Another method to reduce emissions is the use
of plowing instead of sanding.
3.1.1.2 Carryout from Unpaved Areas and Construction Sites—
Mud and dirt carryout from unpaved areas such as parking
lots and construction sites often accounts for a substantial
fraction of paved road silt loadings in many areas. The
elimination of this carryout can significantly reduce paved road
emissions.
As noted earlier, quantification of control efficiencies for
preventive measures is essentially impossible using the standard
before/after measurement approach. The methodology described
below results in upper bounds of emission reductions. That is,
the control afforded cannot be easily described in terms of
percent but rather is discussed in terms of mass emissions
prevented.
Furthermore, tracking of material onto a paved road results
in substantial spatial variation in loading about the access
point. This variation may complicate the modeling of emission
reductions as well as their estimation, although these
difficulties become less important, as the number of unpaved
areas in an area and their access points become larger..
For an individual access point from an unpaved area to a
paved road, let N represent the daily number of vehicles entering
or leaving the area. Let E be given by:
5.5 a/vehicle for N s 25 :.'...'..
E= { (3-1)
13 g/veMcle for N > 25 . :
where E is the unit PM-10 emission increase in g/vehicle.
Finally, if M represents the daily number of vehicle passes on
September 1992
3-10
-------
the paved road, then the net daily emission reduction (g/d) is
given by E x M, assuming complete prevention.
The emission reduction calculated above assumes that
essentially all carryout from the unpaved area is controlled and,
as such, is viewed as an upper limit. In use, a regulatory
agency may choose to assign an effective level of carryout
control by using some fraction of the E values given above to
calculate an emission reduction. Also, the regulatory agency
could choose a percent control efficiency and substantiate
compliance with testing data.
3.1.1.2.1 Curbing—In arid climates, the major sources of
street dust are the exposed soil areas near the streets (e.g.,
unpaved road shoulders). Dust from the exposed road shoulders is
transported to the street surface by turbulence from passing
vehicles, wind erosion, tracking by vehicles, and water runoff.
Mud carryout by motor vehicles is a significant cause of street
surface dust, particularly in areas with abundant rainfall.
In many areas, roadway improvements such as curbing will
result in significant impacts on street dust loadings. These
improvements are important because dust loadings for streets with
uncurbed shoulders are estimated to be four times greater than
that observed for curbed streets (APWA, 1969). Since the major
portion of vehicle miles traveled in any area is concentrated
within the cities, the urban street improvements will have far
greater impact on PM-10 levels than would similar improvements
implemented in county road networks. Accordingly,
intensification of the street improvement plans should be
considered as a potential control for street dust emissions.
Continuous curbs usually reguire gutters and storm sewers
for street water runoff. The cost of gutters and sewers is
greater than the cost of curbing alone.
To increase the effectiveness of street curbing as a dust
control measure, the adjacent soil should be stabilized or
September 1992
3-11
-------
covered to prevent wind erosion or tracking of this soil onto the
street. Clearly, the most effective means of soil protection at
the curb is a sidewalk. A typical and desirable city policy is
to include sidewalks whenever curbs are constructed on major
streets. The effectiveness of this measure has not been
quantified, but it is expected that transfer of exposed soil to
adjacent road surfaces will be decreased significantly.
Curbs are effective in keeping vehicles on the pavement,
thereby eliminating tracking from the edge of the pavement.
However, other techniques such as painting the road 1 to 2 ft
from the edge with a stripe and installing parking caution signs
may accomplish this objective at far less expense.
3.1.1.3 Other Preventive Control Measures—
As shown in Table 3-2, numerous other preventive controls
have been proposed for certain sources of paved road silt
loadings. These controls range from wind fences in desert
regions to keep sand off highways and other roads to measures
designed to prevent losses of materials transported in trucks.
These measures are known to control PM-10 emissions effectively,
but have not been quantified.
It is recommended that, if the use of one or more of these
controls is contemplated in an area, the local control agency
design small-scale field tests of the surface loadings before and
after implementation to determine a reasonable estimate of the
efficiency. Note that, in the design of any program of that
type/ particular attention must be paid to spatial variations in
both sources and controls applied. For example, while a program
for wind fences in desert areas would present few complications
in assessing control, a program to assess the impact of storm
water control or haul truck restrictions must include provisions
for the localized (and possibly, random) nature of the source and
its effects on surrounding roads.
September 1992
3-12
-------
3.1.2 Mitigative Measures
While preventive measures are preferred under the EPA urban
dust policy, some sources of road dust loadings may not be easily
controlled by prevention. Consequently, some mitigative measures
may be necessary to achieve desired goals. This section
discusses demonstrated mitigative measures.
3.1.2.1 Sweeping of Roads—
Mechanical street cleaners employ rotary brooms to remove
surface materials from roads and parking lots. Much of their
effect is cosmetic, in the sense that, while the roadway appears
much cleaner, a substantial fraction of the original dust loading
is emitted during the process. Thus, there is some credence to
claims that mechanical cleaning is as much a source as a control
of particulate emissions.
Measurement-based control efficiency for industrial roads
(Table 3-1) and estimated efficiencies for urban roads both
indicate a maximum (initial) instantaneous control of roughly 25
to 30 percent. Efficiency, of course, can be expected to decrease
prior to the next cleanup. Because of the poor amount of control
broom sweeping provides, it will not be considered as a viable
candidate for BACM.
Vacuum sweepers remove material from paved surfaces by
entraining particles in a moving air stream. A hopper is used to
contain collected material and air exhausts through a filter
system in an open loop. A regenerative sweeper functions in much
the same way, although the air is continuously recycled. In
addition to the vacuum pickup heads, a sweeper may also be
equipped with gutter and other brooms to enhance collection.
Instantaneous control efficiency values were given earlier
in Table 3-1. An average of field measurements indicates an
efficiency of 34 percent for vacuum sweeping.
September 1992
3-13
-------
3.1.2.2 Water Flushing of Roads—
Street flushers remove surface materials from roads and
parking lots using high pressure water sprays. Some systems
supplement the cleaning with broom sweeping after flushing.
Unlike the two sweeping methods, flushing faces some obvious
drawbacks in terms of water usage, potential water pollution, and
the frequent need to return to the water source. However,
flushing generally tends to be more effective in controlling
particulate emissions.
Equations to estimate instantaneous control efficiency
values are given in Table 3-1. Note that water flushing and
flushing followed by broom sweeping represent the two most
effective control methods (on the basis of field emission
measurements) given in that table.
In the case of winter sanding, dust generation potential can
be reduced if the fine materials left on roadways after pavement
drying are cleaned up promptly and without further spreading and
resuspension. Prompt cleaning also keeps abrasives from being
ground into small particles by road traffic or freeze/thawing.
Quick cleanup may not be mandated, however, if a new snowstorm is
likely. Cleanup using combination water flushing/broom sweeping
is recommended as soon as possible after a storm when above-
freezing temperatures keep the flushing water from freezing on
the roadway. If the road is already wet, flushing may not be
required.
3.2 UNPAVED ROADS
There are numerous control options for unpaved travel
surfaces, as shown in Table 3-5. Note that the controls fall
into the three general categories of source extent reductions,
surface improvements, and surface treatment. Each of these is
discussed in greater detail in the following sections.
September 1992
3-14
-------
TABLE 3-5. CONTROL TECHNIQUES FOR UNPAVED TRAVEL SURFACES5
Source extent reduction: Speed reduction
Traffic reduction
Source improvement: Paving
Gravel surface
Surface treatment: Watering
Chemical stabilization
a Table entries reflect EPA draft guidance on urban fugitive
dust control.
September 1992
3-15
-------
3.2.1 Source Extent Reductions
These controls either limit the amount of traffic on a road
to reduce the PM-10 emission rate or lower speeds to reduce the
emission factor value given by Equation (2-6). Examples could
include ride share programs, restriction of roads to certain
vehicle types, or strict enforcement of speed limits. In any
instance, the control afforded by these measures is readily
obtained by the application of the equation.
3.2.2 Surface Improvements
These controls alter the road surface. Unlike surface
treatments (discussed below), these improvements are largely
"one-shot" control methods; that is, periodic retreatments are
not normally required.
The most obvious surface improvement is, of course, paving
an unpaved road. This option is expensive and is probably most
applicable to high volume (more than a few hundred passes per
day) public roads and industrial plant roads that are not subject
to very heavy vehicles (e.g., slag pot carriers, haul trucks,
etc.) or spillage of material in transport. Control efficiency
estimates can be obtained by applying the information of
Section 3-1.
Other improvement methods cover the road surface material
with another material of lower silt content (e.g., covering a
dirt road with gravel or slag, or using a "road carpet1" under
ballast). Because Equation (2-6) shows a linear relationship
between the emission factor and the silt content of the road
surface, any reduction in the silt value is accompanied by an
equivalent reduction in emissions. This type of improvement is
initially much less expensive than paving; however, maintenance
(such as grading and spot reapplication of the cover material)
may be required.
September 1992
3-16
-------
Finally, vegetative cover has been proposed as a surface
improvement for very low traffic volume roads (i.e., access roads
to agricultural fields). Even though vehicle related emissions
from such a road would be quite low, this method will also reduce
wind erosion of the road surface.
3.2.3 Surface Treatments
Surface treatment refers to those control techniques which
require periodic reapplications. Treatments fall into the two
main categories of (1) wet suppression (i.e., watering, possibly
with surfactants or other additives), which keeps the surface wet
to control emissions, and (2) chemical stabilization, which
attempts to change the physical (and, hence, the emissions)
characteristics of the roadway. Necessary reapplication
frequencies may range from several minutes for plain water under
hot, summertime conditions to several weeks (or months) for
chemicals.
Water is usually applied to unpaved roads using a truck with
a gravity or pressure feed. This is only a temporary measure,
and periodic reapplications are necessary to achieve any
substantial level of control efficiency. Some increase in
overall control efficiency is afforded by wetting agents which
reduce surface tension.
Chemical dust suppressants, on the other hand, have much
less frequent reapplication requirements. These suppressants are
designed to alter the roadway, such as cementing loose material
into a fairly impervious surface (thus simulating a paved
surface) or forming a surface which attracts and retains moisture
(thus simulating wet suppression).
Chemical dust suppressants are generally applied to the road
surface as a water solution of the agent. The degree of control
achieved is a direct function of the application intensity
(volume of solution per area), dilution ratio, and frequency
September 1992
3-17
-------
(number of applications per unit time) of the chemical applied to
the surface and also depends on the type and number of vehicles
using the road.
3.2.3.1 Watering—
The control efficiency of unpaved road watering depends
upon: (a) the amount of water applied per unit area of road
surface, (b) the time between reapplications, (c) traffic volume
during that period, and (d) prevailing meteorological conditions
during the period. All of these factors affect the road surface
moisture content. The control efficiency relationship shown in
Figure 3-1 is buried in field tests conducted at a coal-fired
power plant. Surface moisture grab samples over the daily
watering cycle along with the daily traffic flow cycle are needed
to determine an average control efficiency using this figure.
The low control efficiency for watering of unpaved roads and the
need for frequent (almost daily) reapplication preclude the use
of watering as possible BACM.
3.2.3.2 Chemical Treatments—
As noted, some chemicals (most notably salts) simulate wet
suppression by attracting and retaining moisture on the road
surface. These methods are often supplemented by some watering.
It is recommended that control efficiency estimates be obtained
using Figure 3-1 and enforcement be based on grab sample moisture
contents.
The more common chemical dust suppressants form a hard
cemented surface. It is this type of suppressant that is
considered below.
Besides water, petroleum resins (such as Coherex®) have
historically been the products most widely used in industry.
However, considerable interest has been shown at both the plant
and corporate level in alternative chemical dust suppressants.
As a result of this continued interest, several new dust
September 1992
3-18
-------
u
c
WATERING CONTROL
EFFICIENCY ESTIMATES
100%
« 75%
c
o
U
? 50% -
fi.
en
3
O
O
9
n
c
25% -
Ratio of Controlled to Uncontrolled
Surface Moisture Contents
95%
Figure 3-1.
Watering Control Effectiveness for Unpaved Travel
Surfaces.
3-19
September 1992
-------
suppressants have been introduced. These have included asphalt
emulsions, acrylics, and adhesives. In addition, the generic
petroleum resin formulations developed at the Mellon Institute
with funding from the American Iron and Steel Institute (AISI)
have gained considerable attention. These generic suppressants
were designed to be produced on-site at iron and steel plants.
On-site production of this type of suppressant in quantities
commonly used in iron and steel plants has been estimated to
reduce chemical costs by approximately 50 percent (Russell and
Caruso, 1984).
In an earlier test report, average performance curves were
generated for four chemical dust suppressants: (a) a
commercially available petroleum resin, (b) a generic petroleum
resin for on-site production at an industrial facility, (c) an
acrylic cement, and (d) an asphalt emulsion (Muleski and Cowherd,
1987). (Note that at the time of the testing program, these
suppressant types accounted for the majority of the market share
in the iron and steel industry.) The results of this program
were combined with other test results to develop a model to
estimate time-averaged PM-10 control performance. This model is
illustrated in Figure 3-2. Several items are to be noted:
The term "ground inventory" is a measure of residual
effects from previous applications. Ground inventory
is found by adding together the total volume (per unit
area) of concentrate (not solution) since the start of
the dust control season. An example is provided below.
Note that no credit for control is assigned until the
ground inventory exceeds 0.05 gal/yd2.
Because suppressants must be periodically reapplied to
unpaved roads, use of the time-average values given in
the figure are appropriate. Recommended minimum
reapplication frequencies (as well as alternatives) are
discussed later in this section.
September 1992
3-20
-------
CHEMICAL DUST SUPPRESSANT
CONTROL EFFICIENCY MODEL
100
0.05 0.1 0.15 0.2
Ground Inventory (gal/sq yd)
0.25
0.3
Figure 3-2. Average PM10 control efficiency for chemical
suppressants.
3-21
September 1992
-------
Figure 3-2 represents an average of the four
suppressants given above. The basis of the methodology
lies in a similar model for petroleum resins only
(Muleski and Cowherd, 1987). However, agreement
between the control efficiency estimates given by
Figure 3-2 and available field measurements is
reasonably good.
As an example of the use of Figure 3-2, suppose the Equation
(2-6) has been used to estimate a PM-10 emission factor of 2.0
kg/VKT. Further, suppose that starting on May 1, the road is
treated with 0.25 gal/yd2 of a (1 part chemical to 5 parts water)
solution on the first of each month until October. In this
instance, the following average controlled emission factors are
found:
Average
controlled
emission
factor,
kg/VKT
Period
May
June
July
August
September
Ground
inventor
y/ ,
gal /yd'2
0.042
0.083
0.12
0.17
0.21
Average
control
efficienc
y,
percent3
0
68
75
82
88
2.0
0.64
0.50
0.36
0.24
a From Figure 3-1; zero efficiency assigned if ground
inventory is less than 0.05 gal/yd2.
In formulating dust control plans for chemical dust
suppressants, additional topics must be considered. These are
briefly discussed below.
3.2.3.2.1 Use of Paved Road Controls on Chemically Treated
Unpaved Roads—Repeated use of chemical dust suppressants tend,
over time, to form fairly impervious surfaces on unpaved roads.
The resulting surface may permit the use of paved road cleaning
techniques to reduce aggregate loading due to spillage and track-
September 1992
3-22
-------
on. A field program conducted tests on surfaces that had been
flushed and vacuumed 3 days earlier (Muleski and Cowherd, 1987).
(The surfaces themselves had last been chemically treated 70 days
before.) Control efficiency values of 90 percent or more (based
on the uncontrolled emission factor of the unpaved roads) were
found for each particulate size fraction considered.
The use of paved road techniques for "housekeeping" purposes
would appear to have the benefits of both high control
(referenced to an uncontrolled unpaved road) and potentially
relatively low cost (compared to follow-up chemical
applications). Generally, it is recommended that these methods
not be employed until the ground inventory exceeds approximately
0.2 gal/yd2 (0.9 L/m2). Plant personnel should, of course, first
examine the use of paved road techniques on chemically-treated
surfaces in limited areas prior to implementing a full-scale
program.
3.2.3.2.2 Minimum Reapplic.ati.Qn Frequency—Because unpaved
roads in industry are often used for the movement of materials
and are often surrounded by additional unpaved travel areas,
spillage and carryout onto the chemically treated road required
periodic "housekeeping" activities. In addition, gradual
abrasion of the treated surface by traffic will result in loose
material on the surface which should be controlled.
It is recommended that at least dilute reapplications be
employed every month to control loose surface material unless
paved road control techniques are used (as described above).
More frequent reapplications would be required if spillage and
track-on pose particular problems for a road.
3.2.3.2.3 Weather Considerations—Roads generally have
higher moisture contents during cooler periods due to decreased
evaporation. Small increases in surface moisture may result in
large increases in control efficiency (as referenced to the dry
September 1992
3-23
-------
summertime conditions inherent in the AP-42 unpaved road
predictive equation). In addition, application of chemical dust
suppressants during cooler periods of the year may be inadvisable
for traffic safety reasons.
Weather-related application schedules should be considered
prior to implementing any control program. Responsible parties
and regulatory agency personnel should work closely in making
this joint determination.
Compared to the other open dust sources discussed in this
manual, there is a wealth of cost information available for
chemical dust suppressants on unpaved roads. Note that many salt
products are delivered and applied by the same truck. For those
products, costs are easily obtained by contacting a local
distributor.
3.3 STORAGE PILES
The control techniques applicable to storage piles fall into
distinct categories as related to materials handling operations
(including traffic around piles) and wind erosion. In both
cases, the control can be achieved by: (a) source extent
reduction, (b) source improvement related to work practices and
transfer equipment (load-in and load-out operations), and (c)
surface treatment. These control options are summarized in
Table 3-6. The efficiency of these controls ties back to the
emission factor relationships presented earlier in this section.
In most cases, good work practices which confine freshly
exposed material provide substantial opportunities for emission
reduction without the need for investment in a control
application program. For example, pile activity, loading and
unloading, can be confined to leeward (downwind) side of the
pile. This statement also applies to areas around the pile as
well as the pile itself, in particular, spillage of material
caused by pile load-out and maintenance equipment can add a large
September 1992
3-24
-------
TABLE 3-6. CONTROL TECHNIQUES FOR STORAGE PILES
Material handling
Source extent reduction
Mass transfer reduction
Source improvement
Drop height reduction
Wind sheltering
Moisture retention
Surface treatment
Wet suppression
Wind erosion
Source extent reduction
Disturbed area reduction
Disturbance frequency
reduction
Spillage cleanup
Source improvement
Spillage reduction
Disturbed area wind exposure
reduction
Surface treatment
Wet suppression
Chemical stabilization
3-25
September 1992
-------
source component associated with traffic-entrained dust.
Emission inventory calculations show, in fact, that the traffic
dust component may easily dominate over emissions from transfer
of material and wind erosion. The prevention of spillage and
subsequent spreading of material by vehicle tracking is essential
to cost-effective emission control. If spillage cannot be
prevented because of the need for intense use of mobile equipment
in the storage pile area, then regular cleanup should be employed
as a necessary mitigative measure.
Preventive methods for control of windblown emissions from
raw material storage piles include chemical stabilization,
enclosures, and wetting. Physical stabilization by covering the
exposed surface with less erodible aggregate material and/or
vegetative stabilization are seldom practical control methods for
raw material storage piles.
To test the effectiveness of chemical stabilization controls
for wind erosion of storage piles and tailings piles, wind tunnel
measurements have been performed. Although most of this work has
been carried out in laboratory wind tunnels, portable wind
tunnels have been used in the field on storage piles and tailings
piles (Cuscino, Muleski, and Cowherd, 1983; Bohn and Johnson,
1983). Laboratory wind tunnels have also been used with physical
models to measure the effectiveness of wind screens in reducing
surface wind velocity (Studer and Arya, 1988).
3.3.1 Chemical Stabilization
A portable wind tunnel has been used to measure the control
of coal pile wind erosion emissions by a 17 percent solution of
Coherex® in water applied at an intensity of 3.4 L/m2 (0.74
gal/yard2), and a 2.8 percent solution of Dow Chemical M-167
Latex Binder in water applied at an average intensity of 6.8 L/m2
(1.5 gal/yard2) (Cuscino, Muleski, and Cowherd, 1983). The
control efficiency of Coherex* applied at the above intensity to
September 1992
3-26
-------
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 percent for TP and approximately 62
percent for IP and FP. The control efficiency of the latex
binder on a low volatility coking coal is shown in Figure 3-3.
3.3.2 Enclosures
Enclosures are an effective means by which to control
fugitive particulate emissions from open dust sources.
Enclosures can either fully or partially enclose the source.
Included in the category of partial enclosures are porous wind
screens or barriers. This particular type of enclosure is
discussed in detail below.
With the exception of wind fences/barriers, a review of
available literature reveals no quantitative information on the
effectiveness of enclosures to control fugitive dust emissions
from open sources. Types of passive enclosures traditionally
used for open dust control include three-sided bunkers for the
storage of bulk materials, storage silos for various types of
aggregate material (in lieu of open piles), open-ended buildings,
and similar structures. Practically any means that reduces wind
entrainment of particles produced either through erosion of a
dust-producing surface (e.g., storage silos) or by a source
(e.g., front-end loader) is generally effective in controlling
fugitive particulate emissions. However, available data are not
sufficient to quantify emission reductions.
Partial enclosures used for reducing windblown dust from
large exposed areas and storage piles include porous wind fences
and similar types of physical barriers (e.g., trees). The
principle of the wind fence/barrier is to provide an area of
reduced wind velocity which allows settling of the large
particles (which cause saltation) and reduces the particle flux
from the exposed surface on the leeward side of the
September 1992
3-27
-------
100
6.8-rVm2 (1.5gol/yd2)of
2.8% solution in water
80
60-
o
ta»
hU
o
u
40-
Tunncl Wind
Speed * 17 m/s (38 mph)
at 15 cm (6.0 in)
above the test surface
20
Key:
o——
•oTP
•a IP
Time After Application (days)
Figure 3 - 3.
Decay in Control Efficiency of Latex Binder Applied
to Coal Storage Piles
3-28
September 1992
-------
fence/barrier. The control efficiency of wind fences is
dependent on the physical dimensions of the fence relative to the
source being controlled. In general, a porosity (i.e./ percent
open area) of 50 percent seems to be optimum for most
applications. Wind fences/barriers can either be man-made
structures or vegetative in nature.
A number of studies have attempted to determine the
effectiveness of wind fences/barriers for the control of
windblown dust under field conditions. Several of these" studies
have shown both a significant decrease in wind velocity as well
as an increase in sand dune growth on the lee side of the fence
(Chepil and Woodruff, 1963; Carnes and Drehmel, 1982; Larson,
1982; Westec Services, 1984).
Various problems have been noted with the sampling
methodology used in each of the field studies conducted to date.
These problems tend to limit an accurate assessment of the
overall degree of control achievable by wind fences/barriers for
large open sources. Most of this work has either not thoroughly
characterized the velocity profile behind the fence/barrier or
adequately assessed the particle flux from the exposed surface.
A 1988 laboratory wind tunnel study of windbreak
effectiveness for coal storage piles showed area-averaged wind
speed reductions of 50 percent to 70 percent for a 50
percent porosity windbreak with height equal to the pile height
and length equal to the pile base. The windbreak was located
three pile heights upwind from the base of the pile. This study
also suggested "that fugitive dust emissions on the top of the
pile may be controlled locally through the use of a windbreak at
the top of the pile" (Studer and Arya, 1988).
Based on the 1.3 power given in Equation (2-7), reductions
of ~ 50 percent to 70 percent would correspond to ~ 60 percent to
80 percent control requires source-specific evaluation because of
the interrelation of ut and u* (for both controlled and
uncontrolled conditions) in Equation (2-7).
September 1992
3-29
-------
This same laboratory study showed that a storage pile may
itself serve as a wind break by reducing wind speed on the
leeward face (Figure 2-4). The degree of wind sheltering and
associated wind erosion emission reduction is dependent on the
shape of the pile and on the approach angle of the wind to an
elongated pile.
3.3.3 Wet Suppression Systems
Fugitive emissions from aggregate materials handling systems
are frequently controlled by wet suppression systems. These
systems use liquid sprays or foam to suppress the formation of
airborne dust. The primary control mechanisms are those that
prevent emissions through agglomerate formation by combining
small dust particles with larger aggregate or with liquid
droplets. The key factors that affect the degree of
agglomeration and, hence, the performance of the system are the
coverage of the material by the liquid and the ability of the
liquid to "wet" small particles. This section addresses two
types of wet suppression systems—liquid sprays which use water
or water/surfactant mixtures as the wetting agent and systems
which supply foams as the wetting agent.
Liquid spray wet suppression systems can be used to control
dust emissions from materials handling at conveyor transfer
points. The wetting agent can be water or a combination of water
and a chemical surfactant. This surfactant, or surface active
agent, reduces the surface tension of the water. As a result,
the quantity of liquid needed to achieve good control is reduced.
For systems using water only, addition of surfactant can reduce
the quantity of water necessary to achieve a good control by a
ratio of 4:1 or more (USEPA, 1983; JACA Corp., 1979).
The design specifications for wet suppression systems are
generally based on the experience of the design engineer rather
than on established design equations or handbook calculations.
September 1992
3-30
-------
Some general design guidelines that have been reported in the
literature as successful are listed below:
1. A variety of nozzle types have been used on wet
suppression systems, but recent data suggest that hollow cone
nozzles produce the greatest control while minimizing clogging
(U.S. Bureau of Mines, 1982).
2. Optimal droplet size for surface impaction and fine
particle agglomeration is about 500 jim; finer droplets are
affected by drift and surface tension and appear to be less
effective (Courtney and Cheng, 1978).
3. Application of water sprays to the underside of a
conveyor belt improves the performance of wet suppression systems
at belt-to-belt transfer points (Seibel, 1976). Micron-sized
foam application is an alternative to water spray systems. The
primary advantage of foam systems is that they provide equivalent
control at lower moisture addition rates than spray systems.
However, the foam system is more costly and requires the use of
extra materials and equipment. The foam system also achieves
control primarily through the wetting and agglomeration of fine
particles (Seibel, 1976). The following guidelines to achieve
good particle agglomeration have been suggested.
1. The foam can be made to contact the aggregate material
by any means. High velocity impact or other brute force means
are not required.
2. The foam should be distributed throughout the product
material. Inject the foam into free-falling material rather than
cover the product with foam.
3. The amount applied should allow all of the foam to
dissipate. The presence of foam with the product indicates that
either too much foam has been used or it has not been adequately
dispersed within the material.
Available data for both water spray and foam wet suppression
systems are presented in AP-42. The data primarily included
estimates of control efficiency based on concentrations of total
September 1992
3-31
-------
particulate or respirable dust in the workplace atmosphere. Some
data on mass emissions reduction are also presented. The data
should be viewed with caution in that test data ratings are
generally low and only minimal data on process or control system
parameters are presented.
The data in AP-42 do indicate that a wide range of
efficiencies can be obtained from wet suppression systems. For
conveyor transfer stations, liquid spray systems had efficiencies
ranging from 42 percent to 75 percent, while foam systems had
efficiencies ranging from 0 percent to 92 percent. The data are
not sufficient to develop relationships between control or
process parameters and control efficiencies. However, the
following observations relative to the data are noteworthy:
1. The quantity of foam applied to a system does have an
impact on system performance. On grizzly transfer points, foam
rates of 7.5 ft3 to 10.5 ft3 of foam per ton of sand produced
increasing control efficiencies ranging from 68 percent to 98
percent (Volkwein et al., 1983). Foam rates below 5 ft3 per ton
produced no measurable control.
2. Material temperature has an impact on foam performance.
At one plant where sand was being transferred, control
efficiencies ranged from 20 percent to 65 percent when 120 F sand
was handled. When sand temperature was increased to 190 F, all
control efficiencies were below 10 percent (Volkwein et al.,
1983).
3. Data at one plant suggest that undesirable belt sprays
increase control efficiencies for respirable dust (56 percent to
81 percent) (Seibel, 1976).
4. When spray systems and foam systems are used to apply
equivalent moisture concentrations, foam systems appear to
provide greater control (Volkwein et al., 1983). On a grizzly
feed to a crusher, equivalent foam and spray applications
provided 68 percent and 46 percent control efficiency,
respectively.
September 1992
3-32
-------
3.4 CONSTRUCTION/DEMOLITION
Work practice controls refer to those measures which reduce
either emissions potential and/or source extent. These will be
discussed below for both construction and demolition activities.
For construction activities, a number of work practice
controls can be applied to reduce PM-10 emissions from the site.
These include paving of roads and access points early in the
project, compaction or stabilization (chemical or vegetative) of
disturbed soil, phasing of earthmoving activities to reduce
source extent, and reduction of mud/dirt carryout onto paved
streets. Each of these techniques is site-specific. However,
subdivisions, for example, can be constructed in phases (or
plats) whereby the amount of land disturbed is limited to only a
selected number of home sites. Also, subdivision streets can be
constructed and paved when the utilities are installed, thus
reducing the duration of land disturbance.
Finally, increased surface loading on paved city streets due
to mud/dirt carryout can be reduced to mitigate secondary site
impacts. This may involve the installation of a truck wash at
access points to remove mud/dirt from the vehicles prior to
exiting the site or periodic cleaning of the street near site
entrances. All of these techniques require preplanning for
implementation without substantially interfering with the conduct
of the project.
In the case of demolition sites, the work practice controls
which can be employed are far more limited than is the case for
construction. Normally, demolition is an intense activity
conducted over a relatively short timeframe; therefore, measures
to limit source extent are not usually possible. The most
significant technique to limit emissions potential is to control
mud/dirt carryout onto paved city streets. This could be
conducted by installing a truck wash and grizzly to remove mud
and debris from the vehicles as they leave the site. Also,
September 1992
3-33
-------
controlling dust generated by vehicle traffic on the site can be
significant.
Control efficiency values can be obtained by a site-specific
analysis of alternative site preparation schemes based on the
planned level of activity for the entire project using the
emission factors provided above. For mud/dirt carryout, a
quantitative value for control efficiency could be obtained if
street surface loading data for uncontrolled (i.e., those which
do not employ any measures to reduce carryout) and controlled
sites were collected.
3.4.1 Traditional Control Technology
In addition to work practices, a number of open source
controls are also available for reducing PM-10 emissions from
construction and demolition sites. These traditional controls
are: watering of unpaved surfaces; wet suppression for materials
storage, handling, and transfer operations; and wind fences for
control of windblown dust.
The use of water is probably the most widely used method to
control open source emissions. However, very little quantitative
data are available on the efficacy of wet suppression for the
control of fugitive PM-10. This is especially true for materials
storage and handling operations. Some limited data are available
for watering of unpaved surfaces, but estimation of control
efficiency (and thus a watering control plan) is difficult.
Those data which are available are presented below.
It should be noted that treatment of unpaved surfaces using
chemical dust suppressants has not been included in the list of
available controls for construction/demolition. This is due to
the fact that the temporary nature of these operations may not
warrant their use. The same travel surfaces may not be used for
sufficient time to allow reapplications of the chemicals and
achieve cost-effective use of the chemical suppressants. An
September 1992
3-34
-------
exception might be the use of hydroscopic salts which require
only one application at the beginning of the project.
With regard to wind fences, only three studies have been
identified for this particular control technique which attempt to
quantify the degree of control achieved. Wind fences (and other
types of barriers) are extremely cost effective in that they
incur little or no operating and maintenance costs. For this
reason wind fences are an attractive control alternative for
windblown PM-10 emissions.
3.4.2 Watering of Unpaved Surfaces
Watering of unpaved roads is one form of wet dust
suppression. This technique prevents (or suppresses) the fine
particulate from leaving the surface and becoming airborne
through the action of mechanical disturbance or wind. The water
acts to bind the smaller particles to the larger material thus
reducing emissions potential.
The control efficiency of watering of unpaved surfaces is a
direct function of the amount of water applied per unit surface
area (liters per square meter); the frequency of application
(time between reapplication); the volume of traffic traveling
over the surface between applications; and prevailing
meteorological conditions (e.g., wind speed, temperature, etc.).
As stated previously, a number of studies have been conducted
with regard to the efficiency of watering to control dust, but
few have quantified all parameters listed above.
The only specific control efficiency data which are
available for construction and demolition involve the use of
watering to control truck haulage emissions for a road
construction project in Minnesota (Kinsey et al., 1983). Using
the geometric means of the important source characteristics
(i.e., silt content, traffic volume, and surface moisture) and
September 1992
3-35
-------
the regression equation developed from the downwind concentration
data, a PM-10 control efficiency of approximately 50 percent was
obtained for a water application intensity of approximately 0.2
gal/yd2/hour.
It should be noted that truck travel at road construction
sites is only somewhat similar to travel on unpaved roads. The
road bed surface is generally not as compacted as a well-
constructed unpaved road. There are also subtle differences in
surface composition. Care should be taken, therefore, in
estimating control efficiency for noncompacted surfaces.
For more compacted, unpaved surfaces found in construction
and demolition sites, an empirical model for the performance of
watering as a control technique has been developed (Cowherd and
Kinsey, 1986). The supporting data base consists of 14 tests
performed in four States during five different summer and fall
months. The model is:
C * 100
0.. & p d t
i
(3-2)
where: C = average control efficiency, in percent
p = potential average hourly daytime evaporation rate
in mm/h
d = average hourly daytime traffic rate in vehicles
per hour
i = application intensity in L/m2
t = time between applications in h
The term p in the above equation is determined using Figure 3-4
and the relationship:
3-36
September 1992
-------
MEAN ANNUAL CLASS A PAN EVAPORATION
(In Inches)
Figure 3-4. Annual Evaporation Data. {Climatic Atlas, 1968)
3-37 September 1992
-------
0.0049 e (annual average)
p = {
0,0065 e (worst case)
where: p = potential average hourly daytime evaporation rate
(mm/h)
e = mean annual pan evaporation (inches) from Figure 3-4
An alternative approach (which is potentially suitable for a
regulatory format) is shown as Figure 3-1.
Figure 3-1 shows that, between the average uncontrolled
moisture content and a value of twice that, a small increase in
moisture content results in a large increase in control
efficiency. Beyond this point, control efficiency grows slowly
with increased moisture content.
3.4.3 Wet Suppression for Materials^ Storage and Hand!jjig
Wet suppression of materials storage and handling operations
is similar to that used for unpaved surfaces. However, in
addition to plain water, this technique can also use water plus a
chemical surfactant or micronized foam to control fugitive PM-10
Surfactants added to the water supply allow particles to
more easily penetrate the water droplet and increase the total
number of droplets, thus increasing total surface area and
contact potential. Foam is generated by adding a chemical (i.e.,
detergent-like substance) to a relatively small quantity of water
which is then vigorously mixed to produce small bubble, high
energy foam in the 100 to 200 pm size range. The foam uses very
little liquid volume and, when applied to the surface of the bulk
material, wets the fines more effectively than untreatesd water.
As with watering of unpaved surfaces, the control efficiency
of wet suppression for materials storage and handling is
dependent on the same basic application parameters. These
include: the amount of water, water plus surfactant, or foam
September 1992
3-38
-------
applied per unit mass or surface area of material handled (i.e.,
liters per metric ton or square meter); if not continuous, the
time between reapplications; the amount of surfactant added to
the water (i.e., dilution ratio), if any; the method of
application including the number and types of spray nozzles used;
and applicable meteorological conditions occurring on-site.
For suppression using plain water, the most applicable
efficiency information available is for feeder to belt transfer
of coal in mining operations. Control efficiencies of 56 percent
to 81 percent are reported for respirable particulate (particles
< ~ 3.5 /imA) at application intensities of 6.7 to 7.1 L/Mg (1.6
to 1.7 gal/ton), respectively. Assuming that respirable
particulate is essentially equivalent to PM-10, the above control
efficiencies would be representative of similar controls for
construction/demolition. (The above application intensities were
estimated assuming 5 min to discharge 7 Mg of coal and 1.4
L/min/spray nozzle.)
In the case of foam suppression, the most appropriate data
available are for the transfer of sand from a grizzly. Using the
respirable particulate control efficiencies at various foam
application intensities (and assuming respirable particulate is
equivalent to PM-10), the following equation was developed by
simple linear regression of the data compiled by Cowherd and
Kinsey (1986):
C =8.51 + 7..96 (A) . (3-4)
where: C = PM-10 control efficiency in percent
A = application intensity in ft3 foam/ton of material
A coefficient of determination (r^) of 99.97 percent was
obtained for the above equation based on the three data sets used
in its derivation.
September 1992
3-39
-------
An alternate approach (which is potentially suitable for
regulatory formats) involves the use of the recently developed
materials handling equations soon to be published in AP-42, by
determining the "uncontrolled" moisture content of the material
and again after wet suppression.
The above calculations would necessitate the determination
of the amount of water added to the material by laboratory
analysis. This could be accomplished by taking grab samples of
the material before and after application of the wet suppression
technique being employed.
3.4.4 Portable Wind Screens or Fences
The principle of wind screens or fences is to provide a
sheltered region behind the fenceline to allow gravitational
settling of larger particles as well as a reduction in wind
erosion potential. Wind screens or fences reduce the mechanical
turbulence generated by ambient winds in an area the length of
which is many times the physical height of the fence.
As stated previously, wind fences and screens are applicable
to a wide variety of fugitive dust sources. They can be used to
control wind erosion emissions from storage piles or exposed
areas as well as providing a sheltered area for materials
handling operations to reduce entrainment during load-in/load-
out, etc. Fences and screens can be portable and thus capable of
being moved around the site, as needed.
The control efficiency of wind fences is dependent on the
physical dimensions of the fence relative to the source being
controlled. In general, a porosity (i.e., percent open area) of
50 percent seems to be optimum for most applications. Note that
no data directly applicable to construction/demolition activities
were found. According to a recent field study of small soil
storage piles, a screen length of five times the pile diameter, a
screen-to-pile distance of twice the pile height, and SL screen
September 1992
3-40
-------
height equal to the pile height was found best (Zimmer et al.,
1986). Various problems were noted with the sampling methodology
used, however, and it is doubtful that the study adequately
assessed the particle flux from the exposed surface. These
problems tend to limit an accurate assessment of the overall
degree of control achievable by wind fences/barriers for large
open sources.
While not entirely applicable to construction/demolition
activities, results of a laboratory wind tunnel study were used
to estimate 60 percent to 80 percent control efficiencies for
materials handling emissions.
3.4.5 Control of Mud/Dirt Carryout
Mud and dirt carryout from construction and demolition sites
often accounts for a temporary but substantial increase in paved
road emissions in many areas. Elimination of carryout can thus
significantly reduce increases in paved road emissions.
At present, the efficacy of various methods to prevent or
reduce mud/dirt carryout have not been quantified. These
techniques include both methods to remove material from truck
underbodies and tires prior to leaving the site (e.g., a
temporary grizzly with high pressure water sprays) as well as
techniques to periodically remove mud/dirt carryout from paved
streets at the access point(s). The following method has been
developed, however, to conservatively estimate the reduction in
mass emissions due to carryout.
For an individual access point from a paved road to a
typical construction or demolition site, let N represent the
number of vehicles entering or leaving the area on a daily basis.
Let E be given by:
September 1992
3-41
-------
5.5 g/vehicle for N..4 25
(3-5)
13 g/vehicle for N > 25
where E is the unit PM-10 emission increase in g/vehicle pass.
Finally, if M represents the daily number of vehicle passes on
the paved road, then the net daily emission reduction (g/day) is
given by E x M, assuming complete prevention.
The emission reduction calculated above assumes that
essentially all carryout from the unpaved area is either
prevented or removed periodically from the paved surface and, as
such, is viewed as an upper limit. In use, a regulatory agency
may choose to assign an effective level of carryout control by
using some fraction of the E values given above to calculate an
emission reduction.
Alternatively, field measurements of the silt loadings on
paved surfaces at the construction site access point after
control has been implemented, compared with adjacent paved areas,
may also be used to gauge the effectiveness of control programs.
3.5 WIND EROSION OF OPEN AREAS
Wind erosion control of soil surfaces is accomplished by
stabilizing erodible soil particles. The stabilization process
is accomplished in three major successive stages: (a) trapping
of moving soil particles, (b) consolidation and aggregation of
trapped soil particles, and (c) revegetation of the surface
(Chepil and Woodruff, 1963).
The trapping of eroding soil is termed "stilling" of
erosion. This may be effected by roughening the surface, by
placing barriers in the path of the wind, or by burying the
erodible particles during tillage. Trapping is accomplished
naturally by soil crusting resulting from rain followed by a slow
process of revegetation. It should be stressed that the stilling
September 1992
3-42
-------
of erosion is only temporary; to effect a permanent control,
plant cover must be established or plant residues must be
maintained.
In bare soils containing a mixture of erodible and
nonerodible fractions, the quantity of soil eroded by the wind is
limited by the height and number of nonerodible particles that
become exposed on the surface. The removal of erodible particles
continues until the height of the nonerodible particles that
serve as barriers to the wind is increased to a degree that
affords complete shelter to the erodible fractions. If the
nonerodible barriers are low, such as fine gravel, a relatively
large number of pieces are needed for protection of soil from
wind erosion. The gravel in such a case would protect the
erodible portion more by covering than by sheltering from the
wind. Thus, all nonerodible materials on the ground that control
erosion have an element of cover in addition to the barrier
principle which protects the soil. The principles of surface
barriers and cover are, therefore, inseparable.
The above principles extend to almost all elements used in
wind erosion control. All of these control methods are designed
to (a) take up some or all of the wind force so that only the
residual force, if any, is taken up by the erodible soil
fractions; and (b) trap the eroded soil, if any, on the lee side
or among surface roughness elements or barriers, thereby reducing
soil avalanching and intensity of erosion.
In the sections that follow, various control methods are
discussed with respect to their characteristics and effectiveness
in controlling open area wind erosion. Methods include
vegetative cover, soil ridges, windbreaks, crop stirps, chemical
stabilizers, and irrigation.
September 1992
3-43
-------
3.5.1 Chemical Stabilization
A portable wind tunnel has been used to measure the control
of coal surface wind erosion emissions by a 17 percent solution
of Coherex® in water applied at an intensity of 3.4 L/m2 (0.74
gal/yd2), and a 2.8 percent solution of Dow Chemical M-167 Latex
Binder in water applied at an average intensity of 6.8 L/m2 (1.5
gal/yd2) (Cuscino et al., 1983). The control efficiency of
Coherex* applied at the above intensity to an undisturbed 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
percent for TP and approximately 62 percent for IP and FP. The
control efficiency of the latex binder on a low volatility coking
coal is shown in Figure 3-3.
3.5.2 Wind Fences/Barriers
Wind fences/barriers are an effective means by which to
control fugitive particulate emissions from open dust sources.
The principle of the wind fence/barrier is to provide an area of
reduced wind velocity which allows settling of the large
particles (which cause saltation) and reduces the particle flux
from the exposed surface on the leeward side of the
fence/barrier. Wind fence/barriers can either be man-made
structures or vegetative in nature.
Windbreaks consist of trees or shrubs in 1 to 10 rows, wind
and snow fences, solid wooden or rock walls, and earthen banks.
The effectiveness of any barrier depends on the wind velocity and
direction, shape, width, height, and porosity of the barrier.
Nearly all barriers provide maximum reduction in wind
velocity at leeward locations near the barrier, gradually
decreasing downwind. Percentage reductions in wind velocities
for rigid barriers remain constant no matter what the wind
velocity (Chepil and Woodruff, 1963).
September 1992
3-44
-------
Direction of wind influences the size and location of the
protected areas. The area of protection is greatest for winds
perpendicular to the barrier length and least for winds parallel
with the barrier.
The shape of the windbreak indicates that a vertically-
abrupt barrier will provide large reductions in velocity for
relatively short leeward distances, whereas porous barriers
provide smaller reductions in velocity but for more extended
distances.
Height of the barrier is, perhaps, the most important factor
influencing effectiveness. Expressed in multipliers of barrier
height, the zone of wind velocity reduction on the leeward side
may extend to 40 to 50 times the height of the barrier; however,
reductions at those distances are insignificant for wind erosion
control. If complete control is desired, then barriers must be
placed at frequent intervals.
3.5.2.1 Tree Windbreaks—
One-, two-, three-, and five-row barriers of trees are found
to be the most effective arrangement for planting to control wind
erosion. The type of tree species planted also has considerable
influence on the effectiveness of a windbreak. The rate of
growth governs the extent of protection that can be realized in
later years.
3.5.2.2 Artificial Barriers—
Snow fences, fences constructed of board or lath, bamboo and
willow fences, earthen banks, hand-inserted straw rows, and rock
walls have been used for wind erosion control on a rather limited
scale. Because of the high cost of both material and labor
required for construction, their use has been limited to where
high value crops are grown or where overpopulation requires
intensive agriculture.
September 1992
3-45
-------
In the United States, the application of artificial barriers
for wind erosion control has been limited. Snow fences
constructed from strips of lath held together with wire have been
used for protecting vegetable crops. Such fences provide only a
relatively short zone of protection against erosion,
approximately 10 times the height of the barrier.
3.5.2.3 Effectiveness—
A number of studies have attempted to determine the
effectiveness of wind fences/barriers for the control of
windblown dust under field conditions. Several of these studies
have shown both a significant decrease in wind velocity as well
as an increase in sand dune growth on the lee side of the fence
(Chepil and Woodruff, 1963; Carnes and Drehnel, 1982; Larson,
1982; Westec, 1984). The degree of emissions reduction varied
from study to study ranging from 0 to a maximum of about 90
percent depending on test conditions (Larson, 1982; Radkey and
MacCready, 1980). A summary of available test data contained in
the literature on the control achieved by wind fences/barriers is
provided in Table 3-7.
Various problems have been noted with the sampling
methodology used in each of the studies conducted to date. These
problems tend to limit an accurate assessment of the overall
degree of control achievable by wind fences/barriers for large,
open sources. Most of this work has either not thoroughly
characterized the velocity profile behind the fence/barrier or
adequately assessed the particle flux from the exposed surface.
3.5.3 Vegetative Cover
Natural vegetative cover is the most effective, easiest, and
most economical way to maintain an effective control of wind
erosion. In addition to the crops such as grasses, wheat,
sorghum, corn, legumes, and cotton, crop residues are often
September 1992
3-46
-------
TABLE 3-7.
SUMMARY OF AVAILABLE CONTROL EFFICIENCY DATA
FOR WIND FENCES/BARRIERS
Material or
control parameter
(Larson, 1982)
(Radkey and
MacCready, 1980)
/Type of
fence/barrier
Porosity of
fence/barrier
Height/length of
fence/barrier
Type of erodible
material
Material
characteristics
Incident wind
speed
Lee-side wind
speed
Particulate
measurement
technique3
Test data rating13
Measured
particulate
control
efficiency0
Textile fabric
50%
1.8 m/50 m
Fly ash
Percent H20 = 1.6
Percent <50 pm = 14.7
Percent <45 pm = 4.6
Average (no screen) =
4.3 m/s (9.7 mph)
Average (upwind) = 5.32
m/s (11.9 mph)
Average = 2 m/s (4.0
mph) or 64% reduction
U/D = hi-vol and hi-vol
w/SSI (11 tests)
TP = 64% (average)
TSP = 0% (average)
Wood cyclone fence
50%
3 ro/12 m
Mixture of topsoil
and coal
Unknown
Maximum 27 m/s
(60 mph)
Unknown
U/D - Bagnold
catchers (one
test)
TP = 88% (average)
a Hi-vol = high volume air sampler; hi-vol w/SSI = high volume
air sampler with 15 umA size-selective inlet, SSI.
b Data rated using criteria specified in Section 4.4.
c TP = total particulate matter, TSP = total suspended
particulate matter (particles < ~ 30
3-47
September 1992
-------
placed on fallow fields until a permanent crop is started. All
of these methods can remove 5 to 99 percent of the direct wind
force from the soil surface (Zingg, 1954).
3.5.3.1 Effectiveness—
Grasses and legumes are most effective because they provide
a dense, complete cover. Wheat and other small grains are
effective beyond the crucial 2 or 3 months after planting. Corn,
sorghum, and cotton are only of intermediate effectiveness
because they are planted in rows too far apart to protect the
soil.
After harvesting, vegetative residue should be anchored to
the surface (Chepil et al., 1960). Duley (1958) found that
legume residues decay rapidly, while corn and sorghum stalks are
durable. He found wheat and rye straw more resistant to decay
than oat straw.
3.5.3.2 Maintenance—
Excessive tillage, tillage with improper implements, and
overgrazing are the major causes of crop cover destruction.
Effective land management practices must be instituted if wind
erosion is to be controlled.
For grazing, the number of animals per acre should, be
controlled to maximize the use of grass and still maintain
sufficient vegetative cover.
Stubble mulching and minimum tillage or plow-plant systems
of farming tend to maintain vegetative residues on the surface
when the land is fallow. Stubble mulching is a year-round system
in which all tilling, planting, cultivating, and harvesting
operations are performed to provide protection from erosion.
This practice requires the use of tillage implements which
undercut the residue without soil inversion.
September 1992
3-48
-------
3.5.4 Limited Irrigation of Barren Field
The periodic irrigation of a barren field controls blowing
soil by adding moisture which consolidates all particles and
creates a crust upon the soil surface when drying occurs. The
amount of water and frequency of each irrigation during fallow to
maintain a desired level of control would be a function of the
season and of the crusting ability of the soil.
3.6 AGRICULTURE
3.6.1 Tilling
Operational modifications to tilling of the soil include the
use of novel implements or the alteration of cultural techniques
to eliminate some operations altogether. All operational
modifications will affect soil preparation or seed planting
operations. Furthermore, the suggested operational modifications
are crop specific. Estimated PM-10 efficiencies for agricultural
controls are presented in Table 3-8.
The punch planter is a novel implement which might have
applications for emissions reduction from planting cotton, corn,
and lettuce. The punch planter is already being used in sugar
beet production. The punch planter punches a hole and places the
seed into it, as opposed to conventional planters which make a
trough and drop the seeds in at a specified spacing. The
advantage is that punch planters can leave much of the surface
soil and surface crop residues undisturbed. Large-scale use of
the punch planters would require initial capital investments by
the farming industry for new equipment.
Herbicides for weed control is a cultural practice which
could reduce emissions from cultivation for most new crops with
wide enough spacing for cultivation and for some close-grown
crops like wheat. The use of herbicides, however, must be
September 1992
3-49
-------
TABLE 3-8. ESTIMATED PM-10 EFFICIENCIES FOR AGRICULTURAL
CONTROLS21
u>
1
in
o
GO
fl>
T3
<-«•
tt>
3
cr
n>
-5
I— '
vo
v£3
ro
Estimated control efficiency (percent) crop for applicable techniques
Operation affected Process
Control technique • Cotton Barley Alfalfa Rice Com Wheat tomatoes
Punch planter Planting 50 SO
Herbicides Cultivation 100 25a 25a b 100 25a 100
or soil
preparation
Sprinkler irrigation Land planing 90 90 90 c 90 90 90
Laser-directed land Land planing or 30 30 30 30 30 30 30
plane floating
Develop high quality All soil 75
alfalfa preparation
operations
Double crop corn with Disking or 50°
wheat plowing
Aerial seeding Planting 50 3e 50
a Eliminates only some soil preparation operations, whereas in other cases, all cultivation operations are eliminated.
k Herbicides already applied by airplane for majority of acreage.
c Flood irrigation necessary.
** Fifty percent control only for double-cropped acreage.
e Seeding already performed by airplane for majority of acreage.
Lettuce
50
100
90
30
-------
balanced against potential increased herbicide emissions caused
by wind and by water runoffs.
Sprinkler irrigation is an existing cultural technique which
could produce fugitive emission control for any crop which is
currently irrigated by surface watering systems. Sprinkler
irrigation eliminates the need for extensive land planting
operations which surface irrigation requires. However, the
capital investment for sprinkler irrigation equipment and the
increased costs of pumping the water are major deterrents.
The laser-directed land plane is a novel implement which
might yield some emissions controls for surface-irrigated crops.
Laser-guided grading equipment has been used in construction for
years and can be expected to reduce the amount of land planing
required due to its more precise leveling blade. This device
might be retrofitted to existing land planes, but capital
investment funds are required.
The developing of long lasting varieties of alfalfa with
high leaf protein content would help to reduce emissions, because
present.practices require replanting every 3 to 5 years. New
varieties already exist which can last up to 20 years, but the
protein content is low. If longevity and quality could be
combined, the soil would not have to be prepared so often, thus
yielding a subsequent reduction in emissions.
Double-cropping corn with wheat or other grain instead of
corn with corn might reduce fugitive emissions. Since corn
provides so much stubble, it must be plowed or disked under. The
beds must then be formed and shaped for the next corn seed
planting. If wheat or another grain were grown on a bedded
field, then corn could be planted on the beds after the wheat
harvest and stubble removal. The beds would require only
reshaping. This would eliminate a plowing or disking operation
and a bed-forming operation while adding a less dusty wheat
stubble removal operation.
September 1992
3-51
-------
Finally, aerial seeding, which is already used in rice
production, would probably reduce emissions somewhat from alfalfa
and wheat production. However, at least in the case of wheat,
the aerially applied seed must be covered. This covering
operation will produce dust, but it may be less dust than a
ground-planting operation would produce.
September 1992
3-52
-------
SECTION 4
ENVIRONMENTAL ANALYSIS OF BACM
This section discusses the positive environmental effects of
controlling PM-10 from fugitive dust sources. The unfavorable
cross-media impacts of control measures available for BACM
application, such as water pollution, solid waste production, and
energy consumption are also addressed.
The PM-10 emissions are known to adversely affect human
health (especially for sensitive persons), soil and water,
manmade materials, visibility, weather, and possibly climate.
Fine particles that disperse from sources and remain suspended
over relatively long periods of time also create hazards to
transportation, deterioration of economic values, and personal
discomfort.
Human beings at special risk from acute exposures to PM-10
include the elderly and those with preexisting cardiorespiratory
disease conditions. Chronic exposure to PM-10 has been reported
to decrease lung function and increase respiratory disease in
children. These and other studies are examined in the three-
volume document, "Air Quality Criteria for Particulate Matter and
Sulfur Oxides," EPA 600/8-82—029 (1982).
The cited EPA document also examines affects of particulate
emissions on terrestrial ecosystems, visibility, and materials.
Nontoxic fugitive particulate matter from natural and
anthropogenic sources has little impact on terrestrial
ecosystems, unless rates of deposition are very high. However,
suspended particulate matter often soils materials and
infiltrates into sensitive electrical and mechanical equipment.
4-1 September 1992
-------
The PM-10 substantially affects visibility, especially as a
relatively homogenous haze layer that reduces target image
clarity and range of viewing. Visual range is inversely related
to the total extinction value which is in itself closely
proportional to the fine particle mass concentration. Reductions
in visibility can adversely affect both air and ground
transportation, property values and aesthetics.
Climate may also be affected by high concentrations of
PM-10; If the amount of solar energy directed to the earth's
surface is reduced by reflection from a PM-10 haze, the
temperature balance and precipitation patterns may be altered
with conseguent effects upon agricultural production, sea levels
and energy usage.
4.1 COMPARISON OF BASELINE TO POST-BACM PM-10 EMISSIONS
The measures available for BACM application focus on
preventive measures to ensure that potentially emitting surfaces
are kept clean or are stabilized. In the following sections,
baseline emissions in the absence of controls are compared to
emissions after application of BACM. Emissions are
guantitatively assessed for each of the major fugitive dust
sources. The model units discussed in section 2 are used to
estimate the reduction in PM-10 emissions that can be expected
from application of BACM.
4.1.1 Paved Roads
As shown in Table 4-1, major and collector streets under
normal silt loading conditions present the best options for
control based on high emission density. Mitigative control
operations are presented in Table 4-2 for industrial roads and
Table 4-3 for urban roads, together with estimated control
efficiencies. Mitigative control of paved road emissions is
usually not safe for those roads that have traffic intensities
exceeding about 15,000 ADT (Cowherd et al., 1988), which would
4-2 September 1992
-------
TABLE 4-1. PAVED ROAD EMISSIONS POTENTIAL
Roadway category
Freeways/expressways
Major
streets/h ighways
Collection streets
Local streets
Lanes
2: 4
2: 4
2b
2C
Average
daily
traffic
(vehicles)
> 50,000
> 10,000
500-10,000
< 500
Silt loading3
(&'2)
0.022
0.36
0.92
1.41
N
1
26
10
7
Road
emission
potential
(veh-g/m2)
> 1,100
> 3,600
460-9,200
< 705
a 7 = Geometric mean based on corresponding n sample size; silt loading
data presented by city (Cowherd et al., 1988).
b Road width £ 32 ft.
c Road width < 32 ft.
4-3
September 1992
-------
TABLE 4-2. MEASURED EFFICIENCY VALUES FOR PAVED ROAD CONTROLS3
Method Cited Comments
efficiency
Vacuum sweeping 0-58% Field emission measurement
(PM-15) 12,000-cfm blower0
46% Reference 7, based on field
measurement of 30 fan
particulate emissions
Water flushing 69-0.231 Field measurement of PM-15
Vc'a emissions0
Water flushing 96-0.263 Field measurement of PM-15
followed by sweeping V * emissions
a All results based on measurements of air emissions from
industrial paved roads. Broom sweeping measurements
. presented in section 2.3.2.1 (Cowherd and Kinsey, 1986).
PM-10 control efficiency can be assumed to be the same as
that tested. -
|j Water applied at 0.48 gal/yd.
Equation yields efficiency in percent, V = number of vehicle
passes since application.
TABLE 4-3. ESTIMATED PM-10 EMISSION
CONTROL EFFICIENCIES*
Estimated
Method PM-10
efficiency,
%
Vacuum sweeping 34
Improved.vacuum 37
sweeping
a Estimated based on measured
initial and residual < 63-^m
loadings on urban paved roads
and Equation (2-1). Value
reported represents the mean of
13 tests for each method. Broom
sweeping mean (18 tests) given
. in section 2.3.2.1.
0 Sweeping improvements described
in Duncan et al. (1984).
4-4 September 1992
-------
exclude freeways/expressways. Because broom sweepers are
observed to cause, rather than mitigate, dust emissions from dry
roads, they are generally not recommended. Control measures that
aim to prevent, rather than clean up silt loadings on paved
roads, are preferable, with no restriction as to road
classification.
Candidate BACM for paved roads include those preventive
measures designed to keep the silt loading on the road surface as
low as possible. Mud/dirt track-on is the major cause of
elevated silt loadings that intensify particulate emissions from
paved roadways.
Available measures to prevent track-on include curbing to
prevent vehicle traffic on dirt surfaces adjacent to paved roads,
and construction and daily cleaning of paved or graveled access
aprons at construction sites. These aprons enable construction-
related vehicles to "clean" their tires on the apron before
movement to a more heavily travelled paved public roadway.
Candidate BACM also include mitigative measures applied
under specialized conditions. Regular road surface cleanup
operations must follow winter sanding of roads. Road cleaning
cannot be advised under dry conditions. Street cleaners should
operate only when water can be applied (or the road is otherwise
wet) and there is no possibility of refreezing on the roadway.
The model unit proposed in Figure 4-1 is a collector road
segment of 0.8 km (0.5 mi) length (1/4 mi in each direction from
a construction site). The collector road is assumed to have an
average daily traffic (ADT) of 5,000 vehicles, including the
traffic due to the construction site. The construction site is
estimated to be active for 90 days with about 40 truck accesses
each day. Application of the paved road equation with a default
silt loading for collector roads (Table 4-1) produces an emission
factor of 14.0 kg/day for baseline conditions. Emissions due to
carryout onto the portion of the collector road adjacent to the
construction site are estimated to be 65 kg/day.
The addition of a 100-foot long, paved asphalt apron at the
entrance to the construction site with daily cleaning is
4-5 September 1992
-------
estimated to control 86 percent of the track-on to the collector
road. In other words, truck traffic using this apron is expected
to deposit 95 percent of mud and dirt on this apron (to be
cleaned daily), rather than on the 5,000 ADT collector road.
Assuming 86 percent control of track-on to the collector
road, total uncontrolled emissions of 79.0 kg/day can be reduced
to 23.1 kg/day, with an estimated control efficiency of 71
percent for the half-mile length of collector road adjeicent to
the construction site. The cost items presented in Figure 4-1
are analyzed more fully in section 5. These include ceipital
costs, operation and maintenance costs, and enforcement costs.
By dividing the emission reduction by the annualized cost (from
section 5), a calculated cost effectiveness for this control
scenario is 0.61/kg of PM-10 emission reduction.
4.1.2 Unpaved Roads
Significant PM-10 emissions can be expected from unpaved
roads, especially those with traffic greater than 100 ADT and
travelling at speeds above 25 mph. The model unit proposed in
this section is a 1-km segment of unpaved road with 225 ADT, and
an average vehicle with weight of 9 Mg and with 6 wheels. As
shown in Figure 4-2, uncontrolled emissions from this road
segment are estimated as 217 kg/day.
For the model unit, a chemical suppression program has been
designed to control PM-10 emissions. From Table 4-4, it can be
calculated that seven applications of a latex binder are required
to be applied over a period of a year to this particular road to
achieve an estimated PM-10 control efficiency of 75 percent. The
application intensity will be 3.8 L/m2 of 20 percent solution for
the first application. A subsequent application of 4.5 L/m2 (12
percent solution) will occur every 2 weeks after the initial one
and will then be required every 52 days. This chemical
suppression program is estimated to produce a PM-10 emission
reduction of 195 kg/day.
4-6 September 1992
-------
MODEL UNIT
Source classification: Paved Road
Source description: Dirt carryout from construction site onto 0.8 km of paved road
adjacent to site. Resuspension of carryout by vehicles on paved road.
Source specifications: Collector road (5000 ADT) adjacent to construction site.
40 truck accesses/day.
Regulation: No person shall allow any visible accumulation of mud, dirt, dust, or
other material onto paved roads, including paved shoulders adjacent to the site
where construction/demolition activity occurs.
BACM: Pave 30 m of access apron. Flush and sweep paved access apron daily.
Variable Controlled: Surface loading on paved road.
Capital cost items: Paving equipment, material and labor, restoration costs
O&M cost items: Labor and water associated with cleanup (2 hours/day)
Enforcement: Permitting. Visual confirmation of apron cleaning. Silt loading
samples from paved road.
Environmental effects: Energy and fuel use; minor VOC emissions; disposal of
emulsified asphalt/base rock (expected to be very low due to short apron length)
Calculation of PM10 emission reduction:
Uncontrolled: (USEPA, 1988)
Background: 14 kg/day
Construction dirt carryout: 5000 ADT • 13 g/vehicie (if > 25
accesses/day) = 65 kg/day
Controlled:
1 -0.95 • (1-0.855) = 86% control efficiency from road emissions
due to construction site carryout [30m of paved apron
contains 95% of the carryout; from Table 4-2, water flushing
and sweeping yield a control efficiency of 85.5%)
Construction dirt carryout: 65 • (1-0.86) = 9.1 kg/day
Reduction:
R = 55.9 kg/day
Control efficiency: 71%
Figure 4-1. Proposed model unit—paved roads.
4_7 September 1992
-------
MODEL UNIT
Source classification: Unpaved Road
Source description: 1 km of unpaved road. Vehicle entrainment of surface dirt.
Source specifications: 1 km of road (225 AOT) with silt content 10%. No significant
annual rainfall. Vehicle characteristics: average speed of 32 km/h, vehicle weight of 9
Mg, 6 wheels.
Regulation: Unless otherwise exempted, no active unpaved road surfaces shall remain
in an unstabilized state.
BACM: Stabilize unpaved road surface with the chemical suppressant Coherex or
equivalent.
Variable Controlled: Silt content.
Capital cost items: Truck, storage tanks or areas, pumps, piping
O&M cost items: Truck maintenance and repair, labor, fuel, chemicals
Enforcement: Permitting. Reviews of chemical application records. Site inspection
including silt loading.
Environmental effects: Leaching of chemical suppressants; possible VOCs from
petroleum-based resins
Calculation of PM,0 emission reduction:
Uncontrolled: Equation (2-6)
-217kQfday
Controlled:
From Figure 3-4, 75% control is achieved with 3.8 L/m2 of 20%
solution initially. Applications of 4.5 L/m2 of 12% solution
begin two weeks after the initial application and continued
every 52 days following (from Table 4-4).
E = 21 7- (1-0.75) « 54.3 kg/day
Reduction:
R = 195 kg/day
Control efficiency: 75%
Figure 4*2. Proposed model unit—unpaved roads.
4_8 September 1992
-------
TABLE 4-4. EXAMPLE CONTROL PROGRAM DESIGN FOR
COHEREX® APPLIED TO TRAVEL SURFACES*>D
Days between
applications
as a function
of ADT
Average
percent
control
desired
50
75
90
Vehicle passes
between
applications
23,300
11,600
4,650
100
233
16
47
300
78
39
16
500
47
23
9
a Calculated time and vehicle passes between
application are based on the following
conditions:
Suppressant application: -
• 3.8 L of 20 percent solution/in^ (0.83 gallon
of 20 percent solution/yd ) initial
application ,,
• 4.5 L of 12 percent solution/m (1.0 gallon
of 12 percent solution/yd ); reapplications
Vehicular traffic:
• Average weight-9 Mg (8 tons)
• Average wheels-6
• Average speed-29 km/h (20 mph)
Road structure: bearing strength-low to
moderate
b PM-10 = Particles < 10 /miA.
c For reapplications that span time periods
greater than 365 d, the effects of the freeze-
thaw cycle are not incorporated in the reported
values.
4-9 September 1992
-------
The calculated cost effectiveness for chemical suppression
of PM-10 emissions from an unpaved road is estimated as $0.92/kg,
based on the presentation of annualized costs in section 6.
These costs include capital cost items, O&M cost items, and
estimated enforcement costs.
4.1.3 Construction/Demolition Activities
The model unit for construction/demolition activities
consists of a building demolition operation. It will include
control of emissions from loading of debris into trucks, unpaved
road traffic, and carry-out of mud and dirt onto surrounding
roads.
It has not been shown feasible to effectively control dust
emissions from building dismemberment. Explosive demolition will
produce a large cloud of dust emissions that disappears over a
period of several minutes. It is desirable for the settling out
of large particles near the demolition site that wind speeds be
light during explosive dismemberment, but this restriction is not
likely to be a candidate BACH because of low control efficiency
stemming from the fact that the settling velocity of PM-10 is so
small.
Additional control of PM-10 can be achieved by wet
suppression of the debris loadout process, but the following
calculations will demonstrate that this control measure; produces
only a small increase in control efficiency. Also, trucks should
be covered as they deliver the building debris to a burial site.
Figure 4-3 presents the model unit for building demolition.
A building with 18,500 m2 (200,000 ft2) floorspace is to be
explosively demolished, and the resulting debris will be loaded
onto trucks for transport to a burial site. For a period of a
month, 30 trucks will be loaded each day and will remove debris
from the site. The control measures to be applied include wet
suppression of debris handling and transfer, watering of the on-
site area to be travelled by the trucks, and the creation of an
access apron to be cleaned daily by broom sweeping/flushing to
4-10 September 1992
-------
MODEL UNIT
Source classification: Construction/Demolition Activities
Source description: Dismemberment of previous building, debris loading and carry out.
Source specifications: One acre site with 18,500 m2 single floor space. One access point to a
paved street (2000 ADT). Thirty vehicles/day removing debris. Thirty days of work. Mean
annual pan evaporation of 60 inches.
Regulations: The city and its contractors shall not engage in the loading, unloading, conveying or
transporting of bulk materials unless a dust control plan is approved by the APCO which
demonstrates that an overall (80%) efficiency reduction of PM10 emissions from storage piles end
related activities will be achieved.
No person shall allow any visible accumulation of mud, dirt, dust, or other material on the peved
roads, including paves shoulders adjacent to the site where construction/demolition activity
occurs.
BACM: Apply wet suppression to debris handling & transfer (6700 L/kg). Water unpaved travel
surfaces (2 L/m3/hr) daily. Pave 30 m of access apron. Flush and sweep access epron daily.
Variables controlled: Moisture content of traveled surface areas and debris transferred. Surface
loading on adjacent paved road.
Capital cost items: Paving equipment, material and labor, restoration costs, pumps, piping, and
application equipment
O&M cost Items: Labor and water associated with cleanup (2 hours/day)
Enforcement: Permitting. Visual confirmation of water suppression program and apron cleaning.
Moisture content of samples from travel areas and debris. Silt loading samples from paved road.
Environmental effects: Energy and fuel use; minor VOC emissions; disposal of emulsified
asphalt/base rock (expected to be very low due to short apron length); energy costs; leaching of
storage material into ground and surface water.
Calculation of PM10 emission reduction:
Uncontrolled: Figure 4-4
Dismemberment: 4.6 kg (will remain uncontrolled)
Debris loading: 85.1 kg
On-site traffic: 962 kg
Dirt carryout: 780 kg
Controlled:
Dismemberment: 4.6 kg {0% control efficiency)
Debris loading: 37.4 kg (56% control efficiency)
On-site traffic: 163.5 kg (83% control efficiency)
Dirt carryout: 109.2 kg (86% control efficiency)
Reduction: R « 1513kg
Control efficiency: 83%
Figure 4-3. Proposed model unit—building demolition.
4-11 September 1.992
-------
prevent mud/dirt trackout. With these BACM in place, the PM-10
emission reduction is estimated to be 1,517 kg of a total uncon-
trolled total of 1,832 kg. Figure 4-4 gives additional details
on the calculation methodology. Cost effectiveness is estimated
at §8.69/kg to achieve an 83 percent control efficiency for PM-
10. Eliminating wet suppression of the truck loading operation
will only slightly reduce this control efficiency to 80 percent,
and the cost effectiveness will decrease to a more favorable
value of $6.64/kg.
4.1.4 Storage Piles
Wind erosion from storage piles is not believed to produce
significant PM-10 emissions for most nonattainment areas.
control of wind erosion from most storage piles is not cost
effective.
Material transfer operations associated with storage pile
formation or loadout can be controlled by water sprays. The
model storage pile shown in Figure 4-5 is a conically-shaped coal
pile with daily reclaiming. About two-thirds of the pile is
replenished every 3 days. The fully-formed coal pile has
dimensions of 11 m height and 29.2 m base, and contains 11,797 Mg
coal. The amount of coal transferred by conveyor in and out of
the pile every 3 days is estimated at:
2 x 2/3 x 11,797 = 15,729 Mg/3 days
/2.2\l-3
E -= 0.35 (0.0016) \~^l— kg/Mg • 1913736 Mg/yr = 1603 kg/yr
Uncontrolled PM-10 emissions from these transfer operations over
the course of a year are estimated at 1,603 kg/yr. The water
spray system is estimated to control 60 percent of the emissions,
reducing PM-10 emissions by 962 kg/yr. This number, when
4-12 September 1992
-------
• Source Description:
18,500 m2 (200,000 ft2) floor space of a building on a 1-acre site
1 access point to a paved city street (2,000 ADT)
30 vehicles/day removing building debris
30 days project duration
• Assumptions:
No detailed data are available for debris removal activities
No dozing will be performed on site
Negligible exposed areas
8 h/day operation
• Calculation of Uncontrolled Emissions:
From Section 5.1 .2 of USEPA, 1 988, the uncontrolled PM,0 emissions from dismemberment
(E0), debris loading (EJ, and on site traffic (ETr) are calculated as:
EDUTr - (Eo + EL * ETr)
= (0.00025 + 0.0046 + 0.052) kg/ma • 18,500 m2
= 1 .05 Mg PM10 emissions
For mud/dirt carryout (E^ from haul trucks entering and leaving the site, the mean
increase in paved road emissions is calculated using Table 5-2 (USEPA, 1988) for sites
with greater than 25 vehicles/day:
=13 g/vehicle pass • 2,000 vehicles/day • 30 days
s 0.78 Mg PMIO emissions
Therefore, the total emissions (ET) over the duration of the project are:
ET = EOLT, + E^ * 1 .05 Mg + 0.78Mg
= 1 .83 Mg total PM10 emissions
Figure 4-4. Example PM,0 control plan for building demolition.
4-13 September 1992
-------
• Methods of Control:
•Wet suppression of debris handling and transfer (6.7 L/Mg application
intensity)
•Watering of unpaved travel surfaces (0.1 L/rrrVh application intensity)
•Broom sweeping/flushing for removal of mud/dirt earn/out
• Demonstration of Control Program Adequacy:
As stated in Section 5.3.2.1 of USER A, 1988, an efficiency of 56% is typical for wet
suppression of debris loading. Thus, the controlled emissions for debris loading (EcJ would
be:
EQ. « 0.0046 kg PM1(/m2 • 1 8,500 ma • (1 . 0.56) « 0.037 Mg PM10
Using water for dust control for unpaved surfaces. Equations 3-2 and 3-3 as well as
Rgure 3-4 will allow calculation of controlled emissions (assuming the site is located in Los
Angeles, California):
p = 0.0049 • e
= 0.0049 • 60 inches
s 0.29 mm/h
and
0.8 • Q.29 • (60/8) -1
g^
= 82.6%
Therefore, the controlled PM10 emissions for haul truck traffic (Ecr,) would be:
Ecrr = 0.052 kg/ma - 1 8,500 m2 • (1 - 0.826) • Mg/1000 kg
= 0.1674 Mg PM10 emissions
Finally, for removal of mud/dirt carryout using a combination of broom sweeping and
flushing, no prevention efficiency data are available. However, if it is assumed that the
emissions increase on the paved road for this source is reduced by 86%. Consequently,
the controlled emissions of mud/dirt carryout (Eon) = 0.109 Mg PM10 (see Section 5.3.5.1
of USEPA, 1985).
Figure 4-4. (continued)
4-14 September 1992
-------
The total emissions controlled (Eg) are:
EC •= ECL 4- ECT|, 4- ECMD
« (0.037 -I- 0.1674 4- 0.109) Mg
* 0.3134 Mg PM10 after control
Thus, the control efficiency (CE) with wet suppression of debris loading:
CE
(1.83 - Q.3134)
1.83
- 82.9%
Without wet suppression of debris loading:
CE . an
= 80.2%
As demonstrated, wet suppression will not be required as BACM because of its very
small influence in controlling PM10 emissions from construction/demolition activities.
Figure 4-4. (concluded)
4-15 September 1992
-------
MODEL UNIT
Source classification: Storage Piles
Source description: Conically shaped coal storage pile with conveyor transfer operations. Wind erosion
of pile. Ennainment of dust from transfer operations.
Source specifications: Storage pile characteristics: llm high pile, 292 m diameter. 21455 mj volume,
11,797 Mg capacity. 2/3 of pile transferred by conveyor in/out of storage every three days. Uncontrolled
moisture content of 1.5%. Mean wind speed of 2.2m/s.
Regulation: The city and its contractors shall not engage in the loading, unloading, conveying or
transporting of bulk material* unless a dust control plan is approve by the APCO which demonstrates that
an overall (60%) percent reduction of PM,0 emissions from storage piles and related activities will be
achieved.
BACM: Operate water spray system to achieve 60% control efficiency
Variable controlled: Moisture content
Capital cost items: Pumps, piping, nozzles and control system
O&M cost items: Fuel (electricity), water, repair parts, labor
Enforcement: Permitting and inspection of the site. Moisture content of samples from the storage pile.
Environmental effects: Energy costs; leaching of storage material into ground and surface water
Calculation of PM,, emission reduction:
Uncontrolled: Equation (2-6)
E «035 -0.0016 • y* I kg/Mg • 1.913.736Mg/yT
-1,603 kg/yr
Controlled:
E « 1603 • (1-0.60) - 641 kg/yr
Reduction:
R * 962 kg/yr
Control efficiency: 60%
Figure 4-5. Proposed model unit—storage pile
4-16 September 1992
-------
associated with the analytical costs presented in section 5, show
the calculated cost effectiveness to be $9.07/kg.
4.1.5 Open Areas
A good example of a potential BACM applied to open areas is
an unpaved parking lot that is subsequently covered with a
nonerodible surface material. By paving or graveling an unpaved
parking lot with traffic access of greater than 100 vehicles/day,
three sources of emissions are substantially eliminated. These
include the traffic emissions (substantially the same as on an
unpaved road), track-out of mud onto surrounding paved roadways
for subsequent resuspension, and wind erosion of the exposed
surface.
Figure 4-6 presents a model open area to which BACM is
applied for control of wind erosion. The PM-10 control cost
effectiveness is estimated at $12.17/kg for graveling the parking
lot to a depth of 2 inches.
4.1.6 Agricultural Tilling
Agricultural tilling is only partially amenable to effective
dust control practices, because land must be cultivated when the
ground is relatively dry. However, taking land out of production
and planting with permanent grasses or trees are control
alternatives for land classified as "highly erodible" under the
Food Securities Act of 1985. Figure 4-7 examines a model farm
unit of 320 acres, with 25 percent of the field classified as
"highly erodible." The PM-10 control cost effectiveness of
taking land out of agricultural production is calculated as
$7.45/kg, assuming a 100 percent control efficiency and,
$60/acre/yr in farmer payments.
4.2 CROSS MEDIA IMPACTS
Soil stabilization is a major bulwark of a PM-10 control
strategy. This has the added desirable effect of reducing soil
4-17 September 1992
-------
MODEL UNIT
Source classification: Wind Erosion of Open Areas
Source description: Wind erosion from an unpaved parking lot
Source specifications: Dirt lot 100 x 100m. Uniform daily disturbance. Average
particle size 0.56 mm. Local Climatological Data as shown in Figure 6-8 in USEPA
(1988).
Regulation: Effective , the City of shall not cause, permit, suffer, or allow the
operation or use, of an unpaved motor vehicle parking area.
BACM: Cover with a less erodible material, such as gravel, to 2" of depth (70%
control).
Variable controlled: Erodibility of exposed surface
Capital cost items: Material, application equipment, labor
O&M cost items: Periodic grading equipment and labor
Enforcement: Permitting. Visual confirmation of graveling. Silt loading samples from
parking area
Environmental effects: Energy costs
Calculation of PM,0 emission reduction:
Uncontrolled: Equation (2-9)
E = 0.5 • 32.8 g/m2/month • 10,000 m2 • 1 kg/1000 g = 164 kg/month
Controlled:
Using a material of threshold friction velocity u,' > 0.64 m/s
E = 164 • (1-0.70) = 49.2 kg/month
Reduction:
R« 115 kg/month
Control efficiency: 70%
Figure 4-6. Proposed model unit—wind erosion of open areas.
4-18 September 1992
-------
MODEL UNIT
Source classification: Agricultural Tilling
Source description: Suspension of dust by plowing, disking, harrowing, etc.
Source specifications: A 320-acre field tilled/cultivated 5x a year; 18% soil silt
content. 25% of land is classified as "highly credible* under the Food Securities Act
(FSA)
Regulation: Food Securities Act provides for revegetation of highly credible land.
BACM: Place 80 acres of the 320-acre field into the Conservation Reserve Program of
the FSA
Variable Controlled: Source extent
Capital cost items: Seed, fertilizer, fencing, gasoline, labor, transfer and implements.
O&M cost items: Labor, gasoline, fertilizer for grass maintenance; USDA annual
payments
Enforcement cost items: Soil Conservation Service inspection under Conservation
Reserve Program.
Environmental effects: No adverse environmental effects; soil loss by water and wind
reduced to minimal levels
Calculation of PM,0 emission reduction:
Uncontrolled: Equation (2-19)
E = 0.21 • 4.80 • 180-6 Ib/acre • 320 acres • 5/yr = 9136 Ib/yr • 4153 kg/yr
4153 kg = 3115 kg/yr (after grass is planted)
Reduction:
R = 1038 kg/yr
Control efficiency: 25%
Figure 4-7. Proposed model unit—agricultural tilling.
4-19 September 1992
-------
erosion by rainwater and eliminating tracking and washing of
soil-onto-paved traffic areas where it can be resuspended when
dried.
Street dirt contributes a significant amount of pollutants
to urban runoff. As discussed by Lorant (1986), samples
collected from street surfaces identified the smaller particles
as the major carriers of contaminants. Studies by Sartor and
Boyd (1972) indicated that up to 85 percent of pesticides, 95
percent of lead and 60 percent of other heavy metals are found in
sediment particles smaller than 850 microns. For example, Pitt
(1983) showed that concentrations measured in paved parking
runoff or street gutter flow were ten times higher than
concentrations observed from other urban sources. This suggests
that improved control of the silt loading on paved and unpaved
roads will result in a decrease in runoff pollution.
The application of BACM will have some minor influence on
increased water pollution, solid waste production, and energy
consumption. The primary environmental concerns are the leaching
of chemical dust suppressants and storage pile soluble material
into surrounding soils and waters, the disposal of temporary
paving material, and VOC emissions from petroleum-based dust
suppressants.
Chemical dust suppressant are likely to leach out over an
extended period of time. The Arizona DOT (1975) found that the
percentage reduction in extractable residues from areas treated
with chemical dust suppressants ranged between 16 percent and 70
percent and averaged 42 percent. This figure relates to a 56
percent leachout over the 14-month monitoring period.
Calcium chloride produces the same types of environmental
problems when used as a dust suppressant as when used for road
deicing, but when used as a dust suppressant is considerably less
because of the smaller amounts used. Little internal hazard is
connected with the use of calcium chloride due to its low
systemic toxicity. Calcium chloride, under conditions of high
duration or intensity rainfall, can move considerable distances
either as surface runoff or as soil leachate. However, calcium
4-20 September 1992
-------
added by way of dust suppressant is insignificant in comparison
to the amount already present in the environment. Chloride
itself is also present in all natural waters.
There is a potential for mobilizing mercury associated with
the use of calcium chloride. Since calcium and sodium ions
compete with mercury for exchange sites and the chloride ion
reacts with mercury to convert it to a soluble form, the runoff
of calcium chloride could result in the release of mercury from
soils or bottom sediments to lakes or streams.
Lignin sulfonates have very low mobility through soils and
pose little, if any, threat to groundwater when applied to the
surface. Except for trout, this dust suppressant seems to pose
little direct systemic toxicity problems in aguatic organisms,
animals and humans, or vegetation.
Temporary paving material used to create "cleaning aprons"
near construction sites must be disposed of. It is likely to be
both environmentally and cost beneficial to recycle this
gravel/asphalt mixture for construction of new roads in the
vicinity of the construction site.
Volatile organic compounds (VOC's) escape from paving
materials made with petroleum based solvents. The VOC emissions
from cutback asphalt are estimated in AP-42, section 4.5. Only
minor amounts of VOC's are emitted from emulsified asphalts and
asphaltic cement. Emulsified asphalts rely on water evaporation
to cure or on ionic bonding of the emulsion and the aggregate
surface, and can substitute for cutback in almost any
application.
4-21 September 1992
-------
SECTION 5
CONTROL COST ANALYSIS METHODOLOGY
The costs of implementing BACM for PM-10 emissions from
fugitive dust are presented in this section. These costs have
been developed for the model units presented in Section 4. All
costs presented in this chapter have been updated to second
quarter 1991 dollars.
The following discussion describes the process for
calculating the cost of an available control measure for BACM
application. Examples are given for selected model units for
paved roads, unpaved roads, construction/demolition activities,
and wind erosion from open areas.
5.1 ESTIMATING ANNUALIZED COST
Annualized cost is comprised of capital, operating,
overhead, and enforcement/compliance costs. Annualized cost, Ca,
is determined using the following equation:
• ca
where: CRF = capital recovery factor (defined in Equation 5-3).
Ce = direct capital costs.
C0 = annual direct operating costs.
0.5 = overhead cost rate.
C^ = direct annual enforcement and inspection costs.
5-1 September 1992
-------
Annualized cost for an individual control measure is likely
to vary because of economic and environmental conditions. Costs
will vary geographically due to differences in wage rates and
equipment/material costs by region. Costs will also vary because
of 4ifferences in availability of existing equipment and
personnel. For example, local governments that need to
chemically stabilize unpaved roads to meet PM-10 standards and
that already own tank trucks capable of distributing chemical
dust suppressants will have smaller initial costs than other
governments without tank trucks.
The individual elements for Equation 5-1 are described in
the following sections.
5.1.1 Capital Costs. Ce
The capital investment in a fugitive dust control system
consists of those costs incurred in purchase and installation of
equipment, development of support facilities (such as utilities),
and associated labor. In general, capital costs are divided into
direct and indirect costs. Direct capital costs are the costs of
control equipment, support facilities, and labor and materials
needed for installation of utilities. For example,
implementation of chemical dust suppression measures will require
tanks for storage and mixing, spray trucks, pumps, piping, etc.
Direct costs cover the cost of purchase of equipment,
support facilities and auxiliaries, and the cost of installation.
Structures may require certain restrictions which add to the
direct costs. General types of direct capital costs associated
with fugitive dust control systems include:
1. Equipment costs for items such as trucks, sweepers or
vacuums; chemical application equipment; storage tanks; and
facilities.
2. Installation, including adaption into current system
(or replacement of old system), and testing and adjustment of
control apparatus and procedures.
5-2 September 1992
-------
3. Support facility upgrading costs for items such as
newly paved roads or gravel placement over dirt roads.
4. Associated direct costs, such as utility lines and
connections, site development, and materials related to the
acquisition and installation of the capital items.
Indirect capital costs cover the expenses not attributable
to specific equipment or structures. General types of indirect
capital costs associated with fugitive dust emissions control
systems include:
1. Engineering and administrative costs such as
specifications and design work, overhead costs, training of
personnel, safety engineering, and modeling.
2. Construction and field expenses, including buildings
and equipment, warehouses, repair-work areas, temporary
facilities, and tools.
3. Contractor's fee and contingency costs.
The capital cost to be incurred is dependent on the maximum
amount of control desired. For instance, chemical suppressants
may be applied to unpaved roads a maximum of once every month.
In that case, sufficient capital equipment should be obtained to
apply chemical suppressants to the unpaved roads in about a
month's time. If, however, the maximum number of applications is
later increased to twice per month, the current capital
investment may not be able to accommodate the increased
application intensity, and additional capital equipment will have
to be purchased. On the other hand, if enough equipment is
purchased to allow a maximum of one application per week (on the
assumption that at some time it may be needed), and subsequently
only two applications are made per month, then excess capital
equipment is wasted. Therefore, the issue in determining capital
costs is one of optimization: minimizing the capital cost
subject to a minimum equipment utilization rate and minimum
emissions reduction percentage, or alternatively, maximizing the
emissions reduction percentage subject to a maximum equipment
utilization rate and maximum capital cost.
5-3 September 1992
-------
The annualized cost of capital equipment, support
facilities, and related capital expenses is calculated by using a
Capital Recovery Factor (CRF). The CRF provides an average level
of annualized cost associated with one dollar of initial capital
investment. The CRF takes into account the real interest rate of
borrowed funds (a pretax marginal rate of return on private
investment, annual percent as a fraction) and the economic life
of the control system (number of years):
where: i = annual interest rate.
n - economic life of the control system in years.
For instance, given an annual interest rate of 10 percent on
borrowed funds, and an economic life of 15 years on capital
equipment, the CRF will be approximately 0.13. This factor,
multiplied by the total capital costs, provides annualized
capital recovery cost, the annualized capital cost over the life
of the equipment.
5.1.2 Operating Cost. C0
Operating cost will be a major component of many control
measures. First, those control measures that are mechanical in
nature or require repeated applications or maintenance will
likely have operating costs exceeding capital costs over time.
An example is chemical stabilization of unpaved road surfaces
where the costs of labor, fuel, and materials (chemical
stabilizers) will, over time, exceed the cost of capital
equipment (storage tanks, tank truck, spray equipment). Second,
operating costs for many control measures will continue for as
long as control is required. Operating costs typically include:
5-4 September 1992
-------
Utilities: electricity, water, natural gas, telephone,
etc.
Raw materials/process inputs.
Operating labor.
Maintenance and repairs: labor and materials.
By-product costs: material collected during
application, or as a result of operations, that must be
disposed.
Fuel costs.
Generally, operating costs will increase linearly with
increases in application intensity or expansion of source extent
to be controlled (i.e., increase the number of miles of roadway
subject to BACM). However, there are many exceptions to this.
As an example, increasing application rates may result in an
increasing rate of maintenance and repair costs. Estimates of
operating costs need to reflect the impact of the varying
intensities of BACM application.
Operating costs are calculated for a particular year using
the following equation.
c.-cu
+ cz-
h CJ + Cm H
h Cj, * C> '
(5-3)
where: CQ = annual direct operating costs.
GU = annual direct utility costs.
Cr = annual direct raw materials/process inputs.
C^ = annual operating labor.
Cm = annual direct maintenance/repair costs.
GJ.J = annual direct by-product costs.
Cf = annual direct fuel costs.
All of these costs may not apply to a particular control measure.
5.1.2.1 Utilities, Cu—
Utility costs for the current year are calculated directly
based upon utility rates and estimated utility usage. Utility
5-5 September 1992
-------
usage can often be determined from the owner's manual or other
manufacturer product data.
5.1.2.2 Raw Materials/Process Inputs, Cr—
Some control measures, such as chemical stabilization or
paving roads, have raw material and/or process inputs.
Determination of these costs are accomplished by contacting area
vendors and determining unit costs for these materials.
Listed below are popular publications that provide current
cost data:
• Hydrocarbon (petroleum-based products)
• Oil and Gas Journal (petroleum-based products)
• Chemical Marketing Reporter (chemicals)
Purchasing World (major commodities and industrial
equipment)
Engineering News Research (construction costs, heavy
equipment costs, materials costs-gravel, cement, etc.)
McGraw Plant and Equipment Survey (buildings and
equipment)
• Means Building Construction Cost Data (construction and
materials)
It is important in the planning effort to allow for price
swings, because many raw materials and process inputs may be
subject to wide changes in price over narrow time frames. It is
not unusual to allow for a ±15 percent range in price for basic
raw materials like petroleum-based feedstocks. Moreover, an
estimate of miscellaneous losses should be added to the costs of
raw materials. Estimates for price variation allowance: and loss
allowance should be determined by local conditions and the
specific nature of the raw material. For example, if very little
loss is expected either due to the nature of the raw material or
the quality of the specific handling and storage equipment, then
an appropriately low percent loss should be used in estimating
loss allowance.
5-6 September 1992
-------
The amount of raw materials used during the year will depend
upon the application intensity which is dependent on the control
efficiency sought. (See Section 3 for discussion of emission
control effectiveness.) Annual costs for raw materials are
estimated using Equation 5-4.
Cr = (C^ * :N) * (1 + Fv + Fj,) ..: :(5~4).
where: Cr = Raw materials cost.
Cr' = Cost per raw material unit ($/unit).
N = Total units required.
FV = Price variation factor.
FL = Loss factor.
It is important that Cr' is estimated carefully. Many
materials are subject to seasonal price swings, and an estimate
based on a yearly low price may not reflect real costs. If the
material can be stored in sufficient quantities to last through
seasonal usage (i.e., it can be stored and storage facilities are
available), then the use of a yearly average price would be
appropriate. However, if the material is likely to be purchased
during a season of historically high prices* then the yearly high
price should be used for Cr. Moreover, it is important to
observe historic price fluctuations over at least a 5-year
period. Those raw materials that experience large changes in
price may require the use of a multiyear average or weighted
average to accurately reflect Cr.
5.1.2.3 Operating Labor, C^—
Operating labor costs depend on the control measure size and
frequency of application. Costs are calculated by determining
the types of labor (by Dictionary of Occupational Titles job
description) and hours needed for the annual utilization of the
control measure. Data on wage rates can be obtained from the
U.S. Department of Labor's Employment and Earnings (a quarterly
5-7 September 1992
-------
publication). Local wage rates can be estimated from data from
the State Job Service (Employment Security) agency or from the
State Occupational Information Coordinating Council. To cover
the costs of supervision, an additional 15 percent of estimated
labor costs is added.R Equation 5-5 illustrates the method for
calculating labor costs:
where: C1 = Labor costs ($).
W^ = Hourly wage rate for labor category i ($/hour).
H^ = Total annual hours for labor category i.
Fg = Supervision allowance; factor of 1.15.
5.1.2.4 Cost of Maintenance/Repairs, Cm—
Maintenance labor hours in practice are determined by the
maintenance recommendations (as specified by the
manufacturer/builder) of the equipment and property to be used.
If maintenance/repair labor is at a premium over operating labor,
a 10 percent premium should be added to the operating labor wage
rates for each operating labor category.
Unfortunately, the Department of Labor's data limitations do
not allow for distinguishing between operating labor for a
particular operation and the maintenance labor for the operation.
Therefore, maintenance labor costs are determined from operating
labor costs. There are a few common business service maintenance
categories that are recorded, such as heating and air
conditioning maintenance workers; however, for most industrial
machinery, there is no direct maintenance labor estimate.
In addition to labor, maintenance typically requires
materials such as lubricants, solvents, cooling fluids, and
replacement parts. Regularly used lubricant, cleaning, cooling,
etc. materials costs are usually estimated as 100 percent of
5-8 September 1992
-------
total maintenance labor costs. However, when manufacturers'
specifications can allow direct cost estimates, these should be
used instead.
Equation 5-6 shows the method for estimating
maintenance/repair cost.
Wj.flj + (Cp * CRF) + CB .. (5-6)
where: W^ = Hourly wage rate for category i.
H^ = Total annual hours for labor category i.
Cs = Cost of supplies ($).
C = initial cost of replacement parts, including
taxes and freight ($).
C^ = cost of labor ($).
CRF = capital recovery factor for replacement parts;
life span should be defined by manufacturers'
specifications (See Equation 5-4 for CRF
formula).
5.1.2.5 By-Product Costs, Cb—
Some BACM may result in by-product costs (or possibly by-
product revenues which would be a negative value in the direct
operating costs equation) because of possible costs for disposal,
reuse, etc. For example, street vacuuming produces waste
material (dirt, trash, organic material, etc.) that must be
disposed. These costs will have to be estimated directly based
upon local price quotes from local waste disposal firms.
5.1.2.6 Fuel Costs, Cf—
BACM that require machine vehicles, such as street sweepers,
will have fuel costs. These costs are calculated by multiplying
equipment hourly or mileage fuel consumption estimates by
5-9 September 1992
-------
estimated annual operation hours or miles. Due to volatility of
petroleum fuel prices, fuel costs should be estimated based on
anticipated prices. One method for estimating future prices is
to use predicted prices reported by the American Petroleum
Institute or other forecasting organization.
5.1.3 Overhead Costs
Overhead represents the costs associated with the control
measure activity, but not directly tied to the activity. Payroll
overhead costs include worker's compensation, Social Security,
pension contributions, vacations, and other fringe benefits.
System or operational overhead include security costs (like
outfitting vehicles with alarms or storing them in fenced parking
lots), facility lighting and heating, parking areas for
employees, etc. Overhead is typically calculated as 50 percent
of total annualized operating costs (USEPA, 1989).
5.1.4 Enforcement/Compliance Costs
A real cost of implementing control measures will be
enforcement/compliance costs. Government agencies or their
designees with responsibility for air quality programs will need
to insure BACM is being implemented. Industry will need to
document and demonstrate to agencies that they are complying with
the requirements of operating permits. Moreover, many control
measures will be implemented by local or State Government bodies
that will require the air pollution control agency to implement
monitoring programs with these government bodies. Likely costs
to be incurred by enforcement agency and/or industry and
government bodies in compliance and enforcement activities
include:
Additional labor to issue permits and conduct
inspections;
5-10 September 1992
-------
Other operating expenses such as recordkeeping
materials (such as forms, data bases, etc.)/ fuel,
overhead; etc.
• Capital costs such as inspection vehicles, computer
equ ipment; etc.
Many local governments will be able to add much of the
enforcement/compliance functions to existing personnel and
equipment. For example, BACH permitting activity at construction
sites may be easily handled by current inspection staff within
their normal duties. However, costs may vary tremendously from
agency to agency.
Likewise, industry operating under air quality permits that
cover BACM will have varying compliance costs. For example,
firms that currently staff an environmental regulation office may
easily be able to handle additional record-keeping activity, but
firms without such staffing may be forced to hire additional
staff.
Due to such variability, estimating compliance/enforcement
costs is very difficult. However, hours per
compliance/enforcement activity can be estimated. Typical
management/supervisory wage rates for the agency or industry
should be used to determine hourly cost. Generally, Government
time and resources will be spent on:
Permit issuance.
Site inspection/testing.
Permit review/renewal.
Enforcement action; issuance of warnings, fines,
administrative/legal proceedings.
For industry and Government bodies, time and resources will
be spent on:
Permit application preparation.
Additional planning necessary to fulfill permit
requirements.
Recordkeeping associated with control measures.
5-11 September 1992
-------
Total annual compliance/enforcement costs are the sum of
both government and industry annual compliance/enforcement costs.
5.2 ESTIMATING EMISSION REDUCTION
The annual unit emission reduction, AR, is calculated by:
where: AR = Annual unit emission reduction.
M = annual source extent.
e = uncontrolled emission factor.
c = average control efficiency expressed as a
fraction (see Section 3 for estimates of control
efficiencies and uncontrolled emission factors).
For comparison purposes, the source extent should be defined
as a model unit that typifies the sources to be controlled. By
using the same model unit (quantified source extent) for each
source, different control measures for each type of source can be
compared.
5.3 MODEL UNIT EXAMPLES
Example costs have been estimated for the model units of
paved collector roads, unpaved roads, construction/demolition
site, storage pile, and open areas. The calculations follow the
general format presented in the above sections and are shown in a
stepwise method.
5.3.1 Paved Collector Road Model Unit
The model unit is a paved collector road with 5,000 average
daily traffic passes. The collector road is adjacent to a
construction site with daily traffic volume of 40 trucks
5-12 September 1992
-------
(entering and exiting). The construction site operates for 250
days per year.
BACM for the road will be preventive in nature and will
consist of a 30 meter paved access apron to the construction
site. The operating permit for the construction site will
require sufficient flush and sweep cleaning of the apron (at
least once daily) to prevent trackout onto the collector road. A
71 percent control efficiency (control of trackout onto the
collector road) will be achieved.
5.3.1.1 Costs—
Capital costs will primarily consist of the equipment and
materials needed to construct the apron. Other equipment would
include hoses and sweeping equipment needed to clean the apron.
Given the temporary nature of the construction access apron,
asphaltic material will be most likely used. In addition, unless
the construction firm currently owns paving equipment, it will be
unlikely that any paving equipment will be purchased; rather the
firm will contract a paving firm to construct the apron. For
this model unit the construction site is assumed to only be
operational for a l-year period, therefore, there will be no
application of the CFR since all capital costs will be incurred
during the first year.
Operating costs will be limited to the labor and supervision
needed to clean the apron and ensure that it is in good
condition. Most likely 2 h of unskilled labor can handle the
cleaning demands. Overhead costs will be minimal due to the
small operation costs.
Compliance/enforcement costs will include permitting and
inspection costs. Inspection costs should be small since only
visual confirmation that the apron was put into place and is
being cleaned is all that is required. The air pollution control
agency may want to require the construction firm to keep a record
5-13 September 1992
-------
of when and how often the apron is cleaned. The compliance/
enforcement costs presented here are illustrative and may not
reflect actual costs.
Estimates for each of these costs are provided in Table 5-1.
5.3.1.2 Total Annual Reduction, AR—
Total annual reduction of PM-10 emissions is calculated
using Equation 5-7. Given a 5,000 ADT with an emission rate of
13 g/vehicle and a control efficiency of 71 percent, the total
daily emission reduction is 55.9 kg. Assuming the construction
site operates 250 days per year (5 day work week with 10
holidays) then total annual emission reduction is 13,975 kg (250
days x 55.9 kg/day). (See Figure 4-1.)
5.3.2 Unpaved Road Model Unit
The model unit is a 1-km unpaved public road with 225 ADT
and a 10 percent silt content. Average vehicle speed is 32 km/h,
average weight is 9 Mg, and average number of wheels is 6. BACM
is a chemical suppressant program using Coherex*. A 75 percent
control efficiency should be achievable with 7 applications per
year.
5.3.2.1 Costs—
Capital,costs will consist of the chemical truck(s) and
applicator(s), storage tanks or storage area, and pumps and
piping. The trucks and storage tanks may be purchased, or the
job may be contracted out. For this model unit, the items will
be purchased with intent to use for 5 years. For purposes of
annualizing the costs, the capital costs will be annualized using
the CRF with a 10 percent annual interest rate.
Operating costs will include labor costs for operation of
the truck and storage areas as well as maintenance and repair of
the equipment, fuel for the trucks and pumps, and the application
chemicals.
5-14 September 1992
-------
TABLE 5-1. MODEL PAVED ROAD
Model unit
Source:
Source extent;
BACM:
Paved collector roads
Carryout from unpaved area onto a paved road
adjacent to site; collector road (5000 ADT)
adjacent to construction site; 40 truck
access/day for 25 days
Pave 30 m of access apron; daily flush and sweep
paved access apron
Cost categories
Total
Annualized
cost
Capital costs:
Apron construction $1,500
Post-construction restoration costs 1,500
(Apron pavement reclamation revenues) 0
Sweep materials and hoses 50
Operations and maintenance costs:
Labor for sweep and flush (2 hours/day) 750
Supervision-15% of labor 113
Water for flush 500
Overhead costs: 3,988
Enforcement compliance costs:
Permitting 100
$8,501
Cost sources: MRI and Means Building Construction Cost Data.
5-15
September 1992
-------
Enforcement compliance costs include permitting for use of
the chemical, on-site inspection of the application process and
emissions reduction, and record keeping and review. The on-site
inspection will include sample analysis, and record keeping will
include documenting amount of chemical applied, emissions
reduction, and sample analysis results. Once again, these
estimates are illustrative and may not reflect actual costs.
Estimates for each of these costs is provided in Table 5-2.
5.3.2.2 Total Annual Reduction, AR—
Given a 225 ADT with emission rate of 0.964 kg/vehicle/km
and a control efficiency of 75 percent the total daily emission
reduction is 195 kg, or 71,175 kg/yr. (See Figure 4-2.)
5.3.3 Wind Erosion of Open Areas
The model unit is an unpaved parking lot, 100 m x 100 m,
with uniform daily disturbance. Average particle size of the lot
surface is 0.56 mm. BACM for the parking lot will consist of
using larger particle sizes for the surface cover. A 70 percent
control efficiency will be achieved using a less erodible
material, such as gravel.
5.3.3.1 Costs—
A gravel surface material with larger particle size is
estimated to have a life span of 10 yr, with 1,000 m2 of material
of 2 in depth being replaced yearly. Capital costs are
annualized using the CRF. The interest rate is set at 10 percent
for this model unit. Operating costs include periodical grading
of the surface, and operations costs associated with material
replacement in erosion areas. Enforcement compliance costs
include permitting for the lot, on-site inspection of material to
determine particle size and emission reduction, and record
keeping of material addition and grading. Table 5-3 lists
component cost categories and annualized costs.
5-16 September 1992
-------
TABLE 5-2. MODEL UNPAVED ROAD
Model unit
Source: Unpaved road
Source extent: 1 km of road (225 ADT) with silt content of 10%,
average speed of 32 km/h, average vehicle weight
9 Mg, with six wheels
BACM: Chemical suppressant program aimed at 75%
control^from Table 4-4, seven applications of
Coherex a year
Cost categories Annualized
'••'" '": ' • ' •' cost
Capital costs:
Chemical truck(s) with applicator $12,390
Storage tanks or area 5,310
Pumps 885
Piping
Operations and maintenance costs:
Labor for truck and storage area 10,000
Supervision—15% of labor 1,500
Fuel 4,512
Chemicals 5,000
Truck maintenance and repair 10,000
Overhead costs: 15,506
Enforcement compliance costs:
Permitting 100
On-site inspection (sample analysis) 200
Record reviews 50
Total : $65,453
Cost sources: MRI, Means Building Construction Cost Data, and
Chemical Marketing Reporter.
5-17 September 1992
-------
TABLE 5-3. MODEL OPEN AREA
Model unit
Source: Wind erosion
Source extent: Wind erosion from an unpaved parking lot; dirt
lot 100 m x 100 m; uniform daily disturbance;
average particle size 0.56 mm
BACM: Cover with a less erodable material (70%
efficiency)
Cost categories Annual!zed
'" : ' ' ' . ' '... . ' ' '' ' ' COSt
Capital costs:
Surface material and installation $4,069
Operations and maintenance costs:
Periodical grading 5,750
Material replacement in erosion areas 2,500
Overhead costs: 4,125
Enforcement compliance costs:
Permitting 100
On-site inspection 200
Recordkeeping 50
Total ' '' '' $16,794
Cost sources: MRI and Means Building Construction Cost Data.
5-18 September 1992
-------
5.3.3.2 Total Annual Reduction, AR—
Total annual emission reduction from Equation 5-8, given a
10,000 sq m lot with 70 percent control efficiency is 1,380 kg/yr
(see Figure 4-6).
5.3.4 Storage Piles
The model unit is a conically-shaped coal storage pile with
conveyor transfer operations. The pile stands 11 m high, 29.2 m
in diameter and has a volume of 2,455 cu m and capacity of 11,797
Mg. Two-thirds of the pile is transferred by conveyor into and
out of storage daily. The uncontrolled moisture content is 1.5
percent.
BACM for the storage pile will consist of a water spray
system during conveyor transfer to achieve 60 percent control
efficiency.
5.3.4.1 Costs—
Table 5-4 list annualized costs of $8,721. Capital costs
include a submersible pump, 1200 ft of piping, and a control
system for the water. For each conveyor belt, three (3) spray
bars will each provide 10 cc/s, using fanjet sprays.
Operating costs include fuel (electricity) for the pumps,
water, repair parts, and labor. Enforcement compliance costs
include on-site inspection (sampling), record keeping, and
permitting.
5.3.4.2 Total Annual Reduction, AR—
Total annual emission reduction to achieve 60 percent
control efficiency is 962 kg/yr (see Figure 4-5).
5-19 September 1992
-------
TABLE 5-4. MODEL STORAGE PILE
Model unit
Source: Storage piles
Source extent: Conically shaped storage pile; 11 m high; 29.2-ra
diameter; 838-m2 surface area; pile disturbed
every 3 days; moisture content 1.5%, LCD as
shown in Figure 11.2.7-4 of AP-42.
BACM: Watering to achieve 60% efficiency
Cost categories Annualized
' ; ,; • ' • ;"' ' ' • • . : : : COSt
Capital costs:
Pump system $90
Pipe/hose system $1,698
Control system $81
Operations and maintenance costs:
Labor for watering (1 hour/day) $3,163
Supervision-15% of labor $475
Water $56
Electricity $9
Repair parts/labor $633
Overhead costs: $2,167
Enforcement compliance costs:
Permitting $100
On-site inspection $200
Recordkeeping $50
Total ; $8,721
Cost sources: MRI and Means Building Construction Cost Data.
5-20 September 1992
-------
5.3.5 Agricultural Tilling
Conventional agricultural farming operations include
plowing, disking, harrowing, etc. This model unit is a 320-acre
field tilled/cultivated five times per year. The soil has an 18
percent silt content. Twenty-five percent of farmland is
typically classified as "highly erodible" under the Food
Securities Act (FSA).
BACM for the field will consist of placing 80 acres of the
320 acres into the Conservation Resource Program of the FSA.
5.3.5.1 Costs—
Table 5-5 lists annualized costs of $7,730. The
Conservation Resource Program requires specific grasses or trees
be planted and fertilized for a 10-yr period. Capital costs
include initial seed and fertilizer, fencing, gasoline, labor,
and use of tractor and implements. For this model unit, tractor
and implement costs are assumed zero.
Operating costs include periodical fuel, labor, and
fertilizer for grass maintenance. In addition, operating costs
include the payments made by USDA annually. Enforcement
compliance costs include on-site inspection by Soil Conservation
Service and record keeping.
5.3.5.2 Total Annual Reduction, AR—
Total annual emission reduction to achieve 25 percent
control efficiency is 1,038 kg/yr (see Figure 4-7).
5.3.6 Construction/Demolition Activities
The model unit is demolition of a building in an urban area.
The building is 18,500 sq ft located on a 1-acre site. There is
one access point to a paved road carrying 2,000 ADT. The
demolition will take 30 days, during which 30 vehicles per day
will be removing debris.
5-21 September 1992
-------
TABLE 5-5. MODEL AGRICULTURAL TILLING OPERATION
Model unit
Source: Agricultural tilling
Source extent: Wind erosion from agricultural activities; 320-
acre field tilled/cultivated five times per
year; 18% silt content; 25% classified "highly
erodable" under Food Service Act
BACM: Place 80 acres into the Conservation Resource
Program
Cost categories : ! '•••. Annualized
. • ;.'..:....:'.;;.. .':.-....:., •'..:...'..:.-..:'.:. .'. '':'...'• '.'''. ...':•'- cost
Capital costs:
Seed, fertilizer $1,630
Tractor and implements $0
Fuel $41
Fencing $103
Labor $130
Operations and maintenance costs:
Periodical fertilizing $5,000
Fuel $250
Labor $800
USDA annual payments ($4,800)
Overhead costs: $6,050
Enforcement compliance costs:
On-site inspection (sampling) $200
Record keeping $100
:Total ' ;;' ; '• • " ; "......... ... •.':•': $7,730
Cost source: MRI,
5-22 September 1992
-------
BACM for the site will consist of wet suppression of debris
loading and watering of unpaved travel surfaces on the 1-acre
site. A 30 m access apron will be constructed and then swept and
flushed daily.
5.3.6.1 Costs—
Table 5-6 lists annualized costs of $13,190 for BACM which
includes wet suppression of debris transfer operations. Capital
costs include a submersible pump, piping (and/or hoses)/ and
control systems. Capital costs remain the same whether debris
and handling are subject to wet suppression or not.
Operating costs include water and labor for sweeping and
flushing of the access apron, for watering of unpaved travel
surfaces, and for wet suppression of debris. Without wet
suppression of debris, labor costs are cut in half, and water
costs reduced by $20. Enforcement compliance costs include
permitting, on-site inspection (sampling), and record keeping.
5.3.6.2 Total Annual Reduction, AR—
Total emission reduction to achieve 83 percent control
efficiency is 1,517 kg over the 30-day period. Eliminating the
wet suppression of debris from the BACM results in total emission
reduction of 1,465 kg, a 80 percent control efficiency (see
Figures 4-3 and 4-4).
5-23 September 1992
-------
TABLE 5-6. MODEL CONSTRUCTION/DEMOLITION ACTIVITY
-- - Model unit '
Source: Construction/demolition activities
Source extent: Demolition of a building in an urban area;
18,500-m2 building on 1-acre site; one access
point to a paved road (2,000 ADT); 30 days of
work; 30 vehicles/day removing debris
BACM: Wet suppression of debris handling and
transfer (6.7 L/Mg); watering of unpaved
travel surfaces (0.1 L/m2; sweep and flush
access points
Cost categories : •••'.••,' :: Annualized
: ' : : :•••••-.•- ' '•'; . :'' '•'••• '•-.-:' ,• • '"••-••." ••••' . :•:• cost
Capital costs:
Apron construction $ 1,500
Post-construction restoration costs 1,500
Sweep material and hoses 50
Pump system 548
Piping system 774
Control system 50
Operations and maintenance costs:
Labor for wet suppression and watering 3,600
unpaved surfaces (8 hours/day)
Labor for sweeping and flushing access 900
apron (2 hours/day)
Supervision—15% of labor 675
Water for flush 550
Overhead costs: 2,851
Enforcement compliance costs:
Permitting 200
Inspection (included in permitting cost)
Record keeping (included in supervision
cost)
Total . • ' ' ' . ': ;'.•-:. ' :;''-. •: :'-"' '•• $13,190
Cost sources: MRI and Means Building Construction Cost Data.
September 1992
5-24
-------
SECTION 6
OPERATING PERMITS
This section outlines a framework of example dust control
regulations, plans, and operating permits for publicly-owned or
controlled PM-10 sources. Examples are presented to instruct
regulatory personnel who need to implement BACM for PM-10
nonattainment areas.
6.1 PAVED ROADS
Clear and specific enforceable plan provisions are needed to
gain credit for claimed emission reductions in State
implementation plans (SIP's), which for paved road dust sources
will likely rely on record keeping, reporting, and surrogate
factors rather than short-term mass emissions or opacity limits.
Surrogate factors will include control program regulations,
permits, or intergovernmental agreements to institute programs
such as vacuum sweeping, mud/dirt carryout precautions, spill
cleanup, erosion control, and/or measures to prevent or mitigate
entrainment from unpaved adjacent areas. Record review of
control programs (e.g., vacuum sweeping, road sand/salt
application, etc.) and field checks (i.e., road silt loading
sampling) will provide the likely means of compliance
determination for these sources. Because paved road emissions
are directly related to the surface silt loading, the most
reliable regulatory formats are based on loading. Formats viable
for other open dust sources, including opacity measurements,
visible emissions at the property line are generally not
6-1 September 1992
-------
applicable for paved roads because of the lower unit emission
levels involved (e.g., there are usually no visible plumes from a
vehicle pass).
Many States currently have regulations related to the
control of paved roads. Colorado, for example, may require a
control plan from any party that repeatedly deposits materials
which might create fugitive emissions from a public or private
roadway. Note, however, that no quantitative determination of
loading levels is specified.
An alternative format is presented below to suggest how a
quantitative method could be incorporated in a regulation.
Figure 6-1 presents a possible format for use with public paved
road sources. In this example, if the silt loading on a road
with an average traffic volume of 2,000 vehicles per day ever
exceeds 2.9 g/m2 (the "action level"), the regulatory agency may
require the city or its contractor and subcontractors (e.g., a
construction site with mud/dirt carryout) to reduce the silt
loading to a level less than the action level. The action level
is an agency-supplied multiple of baseline measurements of the
surface silt loading and should correspond to a minimum control
efficiency level.
The maximum allowed silt loading requirement could be made
part of a construction permit or an enforceable intergovernmental
agreement. Note that additional traffic due to the construction
activity should be included in the daily traffic volume* used to
determine the action level for the affected roadways. In
addition, a request for permit should be accompanied with a
description of the control technique(s) that will be employed.
Similarly, intergovernmental agreements should clearly and
specifically describe control techniques and associated record
keeping and reporting requirements.
The field measurement of silt loading could either be made a
requirement of the responsible party or be assigned to agency
inspection personnel, or a combination of the two could be used.
6-2 September 1992
-------
SURFACE SILT LOADING (g/ni2)
-n
•n
O
o
m
*<
m
x
O
o- cr —
« o t» o
S 8 =?
Figure 6-1. Possible quantitative format for public paved road
sources.
6-3
September 1992
-------
In either event, certain features of the measurement technique
must be specified.
1. The sampling and analysis methods used to determine silt
loading for compliance inspection should conform to the
techniques used to develop the AP-42 urban paved road equation.
These methods are described in Appendices D and E of the AP-42
document.
2. Arrangements must be made to account for spatial
variation of surface silt loading. Possible suggestions include
(a) visually determining the heaviest loading on the road and
selecting that spot for sampling, (b) sampling the midpoint of
the road length segment of interest, and (c) sampling preselected
strips on the road surface.
3. Provision should be made to grant a "grace period"
following a spill or other accidental increase in loading. An 8-
h period is suggested to allow time for the responsible party to
clean the affected area. This allowance should be made part of a
construction or other permit.
The control efficiency equations presented in Table 3-1
provide a potential regulatory format for paved road sources.
This approach involves inspection of both road cleaning records
and traffic counts. By combining the two sets of information,
regulatory personnel would be able to determine averages
efficiency values for the controlled paved roads. Provision must
be made to collect traffic information. Obtaining traffic data
may require more frequent inspections than for surface loading
samples; however, analysis of traffic data is more easily
accomplished. Surface loading sampling provides an additional
means for checking the success of achieving the estimated control
efficiency.
6.1.1 Example SIP Language
Public paved roads are important PM-10 sources in areas
across the country. Unlike the industrial sources described in
6-4 September 1992
-------
this manual, control of municipal paved roads generally requires
a close working agreement between various Government bodies and
the general public.
6.1.1.1 General Description—
The purpose of this rule is to reduce the amount of
particulate matter, especially the amount of fine particulate
matter (PM-10), reentrained in the ambient air as a result of
motor vehicle traffic on paved roadways and to control sources
that are contributing to particulate matter loadings on the
roadways.
6.1.1.2 Material Transport—
No person shall cause or permit the handling or
transporting of any material in a manner which allows or
may allow controllable particulate matter to become
airborne. Visible dust emissions from the
transportation of materials must be eliminated by
covering stock loads in open-bodied trucks or other
equivalently effective controls.
Earth or other material that is deposited by trucking
and earth-moving equipment on paved streets shall be
reported to the (local Department of Sanitation at
) and removed within 8 h subject to safety
considerations by the party or person responsible for
such deposits.
6.1.1.3 Motor Vehicle Parking Areas—
Effective , the City of
shall not cause, permit, suffer, or
allow the operation or use, of an unpaved motor vehicle
parking area.
Low-use parking area exemption: Motor vehicle parking area
requirements shall not apply to any parking area from which less
than (e.g., 10) vehicles exit on each day. Any person
6-5 September 1992
-------
seeking such an exemption shall: (1) submit a petition to the
Control Officer in writing identifying the location, ownership,
and person(s) responsible for control of the parking area, and
indicating the nature and extent of daily vehicle use; and (2)
receive written approval from the regulating agency that a
low-use exemption has been granted.
6.1.1.4 Erosion and Entraihment From Nearby Areas—
The City of will pave or treat by using
chemical binders, calcium chloride, or acceptable
equivalent materials the following: paved road
shoulders and approach aprons for unpaved roads and
parking areas that connect to paved roads, which are
within the City's right-of-ways or under the City's
control and within X feet (e.g., 25) of roadways
[specify location], in amounts and frequencies as is
necessary to effectively control PM-10 emissions to a
level of X percent control efficiency (e.g., paving—90
percent; chemical treatment per specified requirements—
70 percent). [Include list of roads in memorandum of
understanding and specify whether those areas will be
paved or treated.]
If loose sand, dust, or dust particles are found to
contribute to excessive silt loadings on nearby paved
roads, the Control Officer shall notify the contractor
or user of said public land that said situation is to be
corrected within a specified period of time, dependent
upon the scope and extent of the problem, but in no
case may such a period of time exceed X (e.g., 2) days.
The Control Officer, or a designated agent, must take such
remedial and corrective action as may be deemed appropriate to
relieve, reduce, or remedy the existent dust condition, where the
contractor or user of the subject land, fails to do so.
Any cost incurred in connection with any such remedial or
corrective action by the Control Officer shall be assessed
6-6 September 1992
-------
against the contractor or user of the involved property, and
failure to pay the full amount of such costs shall result in a
lien against contractor or user of real property, which lien
shall remain in full force and effect until any and all such
costs shall have been fully paid, which shall include, but not be
limited to, costs of collection and reasonable attorney's fee
therefore.
[A preferable option is to include provisions in applicable
city contracts that require specified dust control measures and
establish penalties for not meeting contract objectives.]
6.1.1.5 Road Sanding/Salting and Traffic Reduction—
The City of will, beginning with the
(year) winter season, restrict the use of sand used for
antiskid operations to a material with greater than X
percent (e.g., 95) grit retained by a number 100 mesh
sieve screen and a degradation factor of X.
The City of will conduct its street
cleaning once per year at the end of the winter season.
The street cleaning program shall be designed to provide
for maximum effort throughout spring months and shall
provide for adequate personnel and equipment to ensure
thorough cleanup within safety constraints. The City
will begin cleaning the roads sand/salt loadings from
streets per the following priority schedule: [include
schedule in memo of understanding].
6.2 UNPAVED ROADS
There are numerous regulatory formats possible for unpaved
roads. For example, some States rules have been developed using
opacity readings to determine compliance. Michigan and Illinois
formulated rules based on opacity and both resulted in
considerable debates of merit.
6-7 September 1992
-------
It is important to note that opacity has yet to be related
to emission levels from roads. One often-raised question deals
with prevailing wind speeds during opacity readings; ambient air
concentrations (and hence, opacity levels) tend to be greater
under lower wind speeds. Consequently, for a road with even a
constant emission rate, opacity readings would vary indirectly
with wind speed.
Record keeping offers another compliance tool for unpaved
road dust controls. The level of detail needed varies with the
control option employed. Record keeping, together with traffic
records as required, will allow the regulator to estimate control
performance for a variety of control programs, such as for
estimation of chemical suppressant efficiency between
applications. While record keeping affords a convenient method
of assessing long-term control performance, it is important that
regulatory personnel have "spot-check" compliance tools at their
disposal.
For chemically controlled surfaces, it has been found that
the control efficiency equation tends to overestimate the
controlled emission factor (and thus, underestimate instantaneous
control efficiency) (Muleski and Cowherd, 1987). Thus, an
inspector could collect an unpaved sample with a whisk broom and
dustpan and, after laboratory analysis for silt content,
calculate a conservatively low estimate of control efficiency
resulting from the chemical treatment. If a rule is written to
maintain a certain higher level of efficiency, the inspector
could then instruct the responsible party to reapply the chemical
or use paved road controls (if feasible).
6.3 STORAGE PILES
There are several possible regulatory formats for control of
dust emissions from formation and loadout of storage piles.
Opacity standards are suitable for observations at the point of
6-8 September 1992
-------
emissions, such as continuous drop from a stacker; however, in
some States they may not be legally applied at the property line.
For wet suppression and chemical stabilization, suitable
record keeping forms would provide evidence of control plan
implementation. In addition, simple measurements of moisture
level in transferred material or of the crust strength of the
chemically treated surface could be used to verify compliance.
In addition, the surface loading as well as the texture of
material deposited around the pile could be used to check whether
good work practices are being employed relative to pile
reclamation and maintenance operations. The suitability of these
measurements of surrogate parameters for source emissions stems
from the emission factor models which relate the parameters
directly to emission rate.
6.3.1 Example SIP Language
The purpose of this rule is to reduce the amount of
particulate matter, especially the amount of fine particulate
matter (PM-10), entrained in the ambient air related to the
loading or unloading of open storage piles of bulk materials.
6.3.2 Requirements
1. The city and its contractors shall not engage in the
loading, unloading, conveying or transporting of bulk materials
unless a dust control plan is approved by the APCO which
demonstrates that an overall X percent (e.g., 75 percent)
reduction of PM-10 emissions from storage piles and related
activities will be achieved. Control measures may include, but
are not limited to, the following: application of water or
chemical suppressants, application of wind breaks or wind fences,
enclosure of the storage piles, enclosure of conveyor belts,
6-9 September 1992
-------
minimizing material drop at transfer point, securing loads and
cleaning vehicles leaving worksite, and other means as specified
by the APCO.
2. The contractor/operator is in possession of a
currently-valid permit which has been issued by the APCO.
6.3.3 Control of Mud/Dirt Carryout
1. Street cleaning; No person shall engage in any dust-
producing storage pile related activity at any work site unless
the paved streets (including shoulders) adjacent to the site
where the storage pile-related activity occurs are cleaned at a
frequency of not less than X (e.g., once) a day unless:
a. vehicles do not pass from the work site onto
adjacent paved streets, or
b. vehicles that do pass from the work site onto
adjacent paved streets are cleaned and have loads
secured to effectively prevent the carryout or dirt
or mud onto paved street surfaces.
6.4 CONSTRUCTION/DEMOLITION
This section discusses record keeping, measures of control
performance, and enforcement issues as well as an example rule
which implements a permit system for construction and demolition
sites. Example regulatory formats are provided for the following
sources associated with construction/demolition: unpaved roads,
haul roads, disturbed soil, and mud carryout. These example
formats provide a starting point for development of construction
rules in a specific area.
The reader is especially encouraged to review a separate EPA
document issued September 25, 1990, Survey of Construction/
Demolition Open Source Regulations and Dust Control Plans. This
64-page final report issued under EPA Contract 68-02-4395, WA.48,
gives a detailed assessment of existing regulations, presents an
6-10 September 1992
-------
example regulation (reproduced in Table 6-1), and also offers
example dust control plans for four scenarios.
The example regulation presented in Table 6-1 was largely
based on features found during the review of existing and draft
regulations.
Several points should be noted about the example:
1. First, the example presents only a skeleton of a
regulation which must be "fleshed out" for use. For example,
agencies will need to decide if dust control plans are to be
attached to building permits or if a separate air regulatory
permit is to be issued.
6-11 September 1992
-------
TABLE 6-1. EXAMPLE REGULATION
Section 100—General
101 Purpose—To reasonably regulate construction and demolition
activities that release particulate matter emissions to the
ambient atmosphere
102 Applicability-This regulation applies to all construction
and demolition activities within the 's
jurisdiction unless specifically exempted below.
Section 200—Definitions
For the purpose of this regulation, the following definitions
apply
201 APCO (Air Pollution Control Officer)—The person heading the
(agency) or any of his/her designees.
202 Applicant—The individual, public and/or private
corporation, or any other legal entity preparing the dust
control plan described in Section 301.
203 Chemical Stabilization/Suppression—A means of dust control
implemented by any person to mitigate PM-10 emissions by
applying petroleum resins, asphaltic emulsion, acrylics,
adhesives, or any other APCO-approved materials.
204 Construction/Demolition Related Activities—Any on-site
mechanical activities preparatory to or related to the
building, alteration, rehabilitation, or demolition of an
improvement on real property, including but not limited to:
grading, excavation, loading, crushing, cutting, planing,
shaping, or breaking.
205 Disturbed Surface Area—A portion of earth's surface, or
materials placed thereon, which has been physically moved,
uncovered, destabilized, or otherwise modified, thereby
increasing the potential for emission of fugitive dust.
206 Dust Suppressants-Water, hygroscopic materials, chemical
stabilization/ suppression materials (see definition 203),
and other materials not prohibited for use by the
Environmental Protection Agency or any other applicable
law, rule, or regulation, as a treatment material to reduce
PM-10 emissions.
6-12 September 1992
-------
207 Fugitive Dust—The particulate matter entrained in the
ambient air which is caused from man-made and natural
activities such as, but not limited to, movement of soil,
vehicles, equipment, blasting, and wind. This excludes
particulate matter emitted directly in the exhaust of motor
vehicles, other fuel combustion devices, from portable
brazing, soldering, or welding equipment, and from pile
drivers.
208 Lot-A designated parcel, tract, or areas of land
established by plat, subdivision, or as otherwise permitted
by law, to be used, developed, or built upon a unit.
209 Open Area-An unsealed or unpaved motor vehicle parking
area, truck stop, vacant lot, or any other disturbed
surface area located on public or private property which is
subject to wind erosion, and is a source of PM-10
emissions.
210 Paved Surface—An improved street, highway, alley, public
way, easement, or other area that is covered by concrete,
asphaltic concrete, asphalt, or other materials specified
by the APCO.
211 PM-10—Particulate matter with an aerodynamic diameter
smaller than or equal to a nominal 10 n as measured by the
applicable Federal reference method.
212 (PM-10 Dust Prevention and) Control Plan—A written document
that describes dust emission sources present at the site
and identifies the means and strategies used to reduce the
emissions.
213 Site-The real property upon which construction/demolition
activities occur.
214 (Surface, Soil) Stabilization-The process used to mitigate
PM-10 emissions for an extended period of time by applying
petroleum resins, asphaltic emulsion, acrylics, adhesives,
or any other APCO-approved material or physical
stabilization by vegetation or the addition of aggregate
material to the surface.
215 Traffic Volume (ADT)-The average daily traffic (ADT) is the
number of vehicle trips on a paved or unpaved surface
during a 24-h period. The ADT value for a publicly owned
road shall be determined according to the regulations of
the public agency responsible for that road.
6-13 September 1992
-------
216 Unpaved Surface—Any surface not defined as paved in
definition 210 above.
Section 300-Prohibitions/Requirements
301 No person shall engage in any construction/demolition
related activity (as defined above) without having an APCO-
approved PM-10 dust prevention and control plan, unless
exempted below. This control plan will be in writing and,
at a minimum, will
1. briefly describe construction/demolition activities to
be performed at the site that will produce PM-10 dust
emissions. These dust-generating activities shall
include, but not be limited to:
I. Removal of Obstructions (Natural/Man-made)
a. Transfer of the debris into vehicles for
haulage
b. Transportation of the debris on-site
c. Additional transfers of the debris (if on-
site, as for fill material)
II. Preparation of the Site
a. Bulldozing and scraping operations
b. Truck transportation of materials (such as
"imported" fill) on-site
c. Transfers of materials
III. Construction Operations
a. Traffic on paved surfaces and staging areas
b. Traffic on unpaved surfaces and staging
areas
2. present estimated uncontrolled PM-10 emission rates for
each activity and summarize the total uncontrolled PM-
10 emissions expected.
3. describe the control measures (if any) to be applied to
each activity and estimate the corresponding controlled
emission rate for each activity.
4. estimate the overall efficiency of the control plan by
comparing the total controlled emissions to total
uncontrolled emissions. (Note that the APCO may choose
to prescribe a minimum target overall efficiency for
the control plan.)
The applicant is responsible for ensuring that each
contractor or subcontractor working at the site adhere to
the provisions of the dust control plan.
6-14 September 1992
-------
The APCO shall make available for inspection examples of
approved dust control plans at the offices of
301 Unless specifically exempted below, no person shall allow
any visible accumulation of mud, dirt, dust, or -other
material on the paved roads, including paved shoulders
adjacent to the site where construction/demolition
activity occurs. The methods used to prevent accumulation
as well as the scheduled frequency of cleaning must be
addressed in the dust control plan.
302 Unless specifically exempted below, disturbed surfaces may
not be allowed to remain in an unstabilized state.
Disturbed surfaces must be stabilized against wind and
water erosion within calendar days after the
disturbing activity ceases. In no event shall a disturbed
area be allowed to remain unstabilized for a period
greater than calendar days. The method(s) used to
stabilize the surface shall be described in the dust
control plan.
303 As evidence of control application, the applicant shall
keep dust control records on agency-supplied forms. These
forms will be included with the APCO's written approval of
the applicant's dust control plan. Records are to be kept
current, be submitted upon the request of the APCO, and be
open for inspection during unscheduled inspections.
304 For construction projects with a duration of at least
calendar days, the APCO shall perform at least one on-
site inspection. Prior to this scheduled inspection, the
APCO may require the applicant to furnish information or
other records.
305 For construction projects with a duration of at least
calendar days, the APCO will formally review the dust
control plan within calendar days of the on-site
inspection.
Section 400—Exemptions
The following sources are specifically exempted from the
provision of this regulation:
401 Construction/demolition activity involving a floor plan of
less than sq feet
6-15 September 1992
-------
402 Any construction/demolition meeting the following activity
levels or requirements
1. occurring entirely within an enclosed structure from
which no visible airborne particulate matter escapes;
2. modifications to the residential dwellings by the
owner/occupant that do not require building permits;
3. movement of less than cubic yards of dirt.
403 Disturbed surface areas of less than acre.
404 The implosion or mechanical dismemberment of any
structure. (Note, however, that this activity may be
subject to regulation , which requires a permit or
variance to be granted.
405 Blasting of rock or other earthen materials in conjunction
with construction/ demolition activities. (Note, however,
that this activity may be subject to regulation ,
which requires a permit or variance to be granted.)
6-16 September 1992
-------
Similarly, it is important that regulators have legal
counsel rephrase the example for consistency with State and local
laws. Table 6-1, for example, only prohibits persons from
"allowing" certain situations; many agencies will need to
supplement this with verbs such as "cause" or "permit." Also, no
specific mention of fees or penalties is made.
2. The example regulation contains several blank fields for
items such as the minimum size of areas to be considered or time
periods within which control must be applied. Agencies need to
determine an appropriate value for each blank.
3. As noted in the example, dust emissions resulting from
mechanical dismemberment or implosion of an existing structure or
from blasting of rock are not covered by the regulation.
However, it is recommended that agencies provide additional
phrasing referring to a separate permit or variance to cover this
type of emission source.
4. Readers are reminded that the regulation given in
Table 6-1 is meant solely as an example and is intended only to
provide a general framework around which regulations may be
developed. Agencies should freely add or delete material as
appropriate for their jurisdictions.
6.4.1 Permit System
The regulatory approach involves the implementation and
enforcement of a permit program for construction and demolition
sites. A permit system would require the site operator to file
an application with the appropriate regulatory agency having
jurisdiction. This permit application would include the specific
dust control plan to be implemented at the site which would
involve the individual elements discussed in Section 3.4.
The air permit for construction and demolition sites would
be coupled to the standard building or demolition permitting
process whereby no permit to conduct such activity would be
issued by the county or city until such time that the air permit
6-17 September 1992
-------
is approved. To reduce the burden of processing large numbers of
such permits, a de minimis level would be established whereby
construction and demolition projects below a certain cut-off size
would not require an air permit. This de minimis level would
depend on local factors such as the amount of emission reduction
required to meet the applicable PM-10 NAAQS.
As part of the permit application, record keeping should be
one of the main conditions for approval. Records of site
activity and control should be submitted to the regulatory agency
on a monthly basis as indicated above. These records must be
certified by a responsible party as to their completeness and
accuracy. All site records should be maintained by the local
agency for the duration of the project.
To enforce the dust control plan submitted as part of the
permit application, field audits of key control parameters should
be made by regulatory personnel. The results of these audits
would then be compared to site records for that period to
determine compliance with permit conditions. An example form to
be used by regulatory personnel during inspection of the site is
shown in Figure 6-2. An example permit for a contractor
operating a construction site is shown in Figure 6-3.
No quantitative data are required for enforcement of the
dust control plan. This eliminates the need for a set
performance standard (e.g., opacity limits) against which the
site operator is evaluated. This approach is, however,
predicated on the fact that strict implementation of the dust
control plan will achieve certain reductions in PM-10 emissions
associated with site operation.
6.4.2 Other Indirect Measures of Control Performance
The most obvious approach to indirectly measuring control
performance involves the collection and analysis of material
samples from various sources operating on-site. For mud/dirt
carryout, collection of surface samples at site access points and
6-18 September 1992
-------
Type of construction activity (check one)
a. Residential
b. Commercial
c. Industrial
.Additional description (i.e., multiunit, residential, or
suburban commercial, etc.)
2. How long have you worked at this location?
Note: In the case of a multiyear project, we are only
interested in the current season.
3. How long is the job projected to last?
4. What percentage of the work is completed?
5. What construction activities are you currently performing?
6. What construction activities have you been performing over
the past week to 10 days?
7. What is the construction activity's source extent which is
currently being performed (e.g., tons of earth moved/day or
yards of concrete poured/day)?
8. Estimate the number of daily vehicle passes through the site
entrance.
9. What types of vehicles enter the site daily and what
percentage of the traffic is of each type?
Vehicle type Percent
a. Cars
b. Pickups/vans
c. Medium-duty trucks
d. Other
10. Do you employ control measures to keep dust down? If
yes, what type?
11. What is the usual frequency and intensity of application?
When was the most recent application?
Figure 6-2. Questionnaire for construction site personnel.
6-19 September 1992
-------
THIS PERMIT HILL BE PROMINENTLY DISPLAYED IN THE
ON-SITE CONSTRUCTION OFFICE
Location: No. of Acres:
Name of Project:
PERMITTEE: Telephone No.:
Address:
Prime Contractor: Telephone No.:
Subcontractor: Telephone No.:
Issue Date of Permit: Expiration Date of Permit:
PERMIT NO.: FEE: $ RECEIPT NO.:
THE PERMITTEE SHALL COMPLY WITH THE FOLLOWING CONDITIONS:
1. (Reference to local APCD regulation for construction/demolition-related
activities.)
2. The PERMITTEE is responsible for dust control from commencement of
project to final completion. Areas which will require particular
.ATTENTION:
a. Unimproved access roads used for entrance to or exit from
construction site.
b. Areas in and around building(s) being constructed.
c. Dirt and mud deposited on adjacent improved streets and roads.
3. If wind conditions are such that PERMITTEE cannot control dust,
PERMITTEE shall shut down operations (except for equipment used for dust
control).
4. The PERMITTEE is responsible for ensuring his contractor(s) and/or
subcontracteds) and all other persons abide by the conditions of the
permit from commencement of project to final completion.
5. The PERMITTEE also is subject to compliance with all applicable state,
county, and local ordinances and regulations. Issuance of this permit
shall not be a defense to violation of above-referenced statutes,
ordinances, and regulations.
6. On-site permit conditions (attached)
Air Pollution Control Division (date)
Figure 6-3. Example dust permit.
6-20 September 1992
-------
analysis of these samples for silt content would indicate the
efficacy of control for this particular source. The silt
loadings obtained could be compared with "typical" surface
loading values for similar uncontrolled sites to determine the
degree of loading (and thus emissions) reductions achieved. This
would, of course, necessitate the availability of a data base of
"uncontrolled" silt loadings due to mud/dirt carryout for a wide
variety of construction and demolition sites for comparison with
site-specific data.
Another indirect measure of control efficiency can be
determined from the collection and analysis of material samples
from unpaved surfaces and materials handling and storage
operations. In this case, analysis of the moisture content of
these samples would indicate the amount of water applied and thus
the degree of control achieved by wet suppression. Appropriate
equations presented in Section 3.4 would be used to determine
control efficiency based on the sample data.
6.5 WIND EROSION
Potential regulatory formats for control of open area wind
erosion are listed in Table 6-2. These focus on appropriate
measures for compliance determination. An example regulation for
water mining activities is presented in Figure 6-4.
6.5.1 Example SIP Language
The purpose of this rule is to reduce the amount of
particulate matter, especially the amount of fine particulate
matter (PM-10), entrained in the ambient air as a result of
emissions from open areas.
6-21 September 1992
-------
TABLE 6-2. METHODS FOR COMPLIANCE DETERMINATION
Source types
Permits
Field audits
Work practices
(recordkeeping)
Emission measurement
Construction
areas
Yes
Vacant lots
Threshold friction velocity
Moisture content
Visible erosion (scouring)
Yes-cond. on area Threshold friction velocity
disturbed Moisture content
Visible erosion (scouring)
Unpaved parking Yes Threshold friction velocity
lots Moisture content
Feed lots
Staging area
<^ Off-road
N> recreation area
to
Landfills
Yes-cond. on
size-where
allowed
Yes
Yes
Yes
Moisture content
Threshold friction velocity
Moisture content
Visible erosion (scouring)
Wet stabilization
Chemical stabilization
Wind fences
Chemical stabilization Vegetative
cover (%)
Graveling
Chemical stabilization
Wet suppression (sprinklers)
Wind fences
Wet stabilization
Chemical stabilization
Wind fences
Limit area disturbed
Limit vehicles (emission
activity)
Limit working face
Wet suppression of
access and working
area
Vegetative cover (%)
% V.E. at property line/source;
PM-iQ/TSP concentration at
property line
% V.E. at property line/source;
PM.JQ/TSP concentration at
property line
% V.E. at property line/source; PM10/TSP
concentration at
property line
% V.E. at property line/source;
PM.JQ/TSP concentration at
property line
% V.E. at property line/source;
PM-jQ/TSP concentration at
property line
% V.E. at property line/source;
PMjQ/TSP concentration at
property line
a*
ro
vO
VO
NJ
Land disposal
(spreading)
Yes
Retired farm land No
H2O mining Yes
Dry washes & No
river beds
Unpaved air strip Yes
Threshold friction velocity
Moisture content
Visible erosion
Threshold friction velocity
Moisture content
Visible erosion
(continued)
Chemical stabilization
Vegetative cover (%)
Wind fences
Vegetative cover (%)
Vegetative cover (%)
Prohibit motor vehicles
Chemical stabilization
% V.E. at property line/source;
PM.JQ/TSP concentration at
property line
-------
REGULATION-PARTICULATE MATTER
RULE-WATER MINING ACTIVITIES
General
a. The purpose of this Rule is to reduce the amount of particulate matter,
especially fine particulate matter (PM-10) entrained in the ambient air
related to water mining activities.
Definitions
a. For the purpose of this Rule, water mining activities are defined as
those activities related to the production, diversion, storage, or
conveyance of water which has been developed for export purposes.
b. Dust: Particulate matter, excluding any materials emitted directly in
the exhaust of motor vehicles and other internal combustion engines, from
portable brazing, soldering, or welding equipment, and from piledrivers.
c. Particulate matter: Any material emitted or entrained into the air as
liquid or solid particles.
d. PM-10: Particulate matter with an aerodynamic diameter of a nominal
10 fan or less as measured by reference or equivalent methods that meet
the requirements specified for PM-10 in 40 CFR Part 50, Appendix J.
e. Reasonably available dust control measures: Techniques used to prevent
the emission and/or airborne transport of dust and dirt from water mining
activities including: application of water or other liquids, covering,
paving, enclosing, shrouding, compacting, stabilizing, planting,
cleaning, or such other measures the Air Pollution Control Officer (APCO)
may specify to accomplish equal or greater control.
Requirements
No person shall engage in any water mining activity unless all of the
following conditions are satisfied:
a. A dust control plan is approved by the APCO which demonstrates that an
overall x (e.g., 75) percent reduction from water mining activities will
be achieved by applying reasonably available control measures. Such
measures may include, but are not limited to, revegetation, chemical
stabilization, application of wind fences, and other means as specified
by the APCO.
b. The owner/operator is in possession of a currently valid permit which has
been issued by the APCO.
Record Control Application
The owner and/or operator shall record the evidence of the application of the
control measures. Records shall be submitted upon request from APCO, and
shall be open for inspection during unscheduled audits.
Figure 6-4. Example regulation for water mining activities.
6-23 September 1992
-------
6.5.2 Requirements
6.5.2.1 Parking Lots, Truck Stops, Driving, etc.—
The City of shall not operate, maintain,
use, or permit the use of any area larger than x (e.g., 5,000)
square feet for the parking, storage, or servicing of more than x
(e.g., 6) vehicles in any one day, unless a dust control plan is
approved by the APCO which demonstrates an overall x (e.g., 75
percent) reduction of PM-10.
6.5.2.2 Industrial, Manufacturing and Commercial Staging Areas—
The City of shall not allow the operation,
use or maintenance of a staging area larger than x (e.g., 5,000)
square feet, unless a dust control plan is approved by the APCO
which demonstrates an overall x (e.g., 75 percent) reduction of
PM-10 emissions from the staging area will be achieved by
reasonably available measures. Such measures may include, but
are not limited to, adequate use of chemical suppressants,
paving, and other means, as specified by the APCO.
6.5.2.3 Record Control Application—
The owner and/or operator shall record the evidence of the
application of the control measures. Records shall be submitted
upon request from APCO and shall be open for inspection during
unscheduled audits.
6.6 AGRICULTURAL TILLING
Land classified as "highly erodible" (HEL) is already
controlled for water and wind erosion through the Food Security
Act (FSA) of 1985. Another provision of the FSA has paid farmers
to take HEL out of production under the Conservation Reserve
Program. This program commits a minimum of 40 million acres to
permanent ground cover.
6-24 September 1992
-------
The Conservation Compliance provision of the FSA requires
that tillage practices be modified to leave more crop residue on
the surface. For example, V-blade implements undercut the roots
of surface vegetation, rather than plowing plants under the soil.
Other modified tillage practices may also have the potential
to reduce PM-10 emissions. Currently, the agricultural industry
is working with the EPA and California air quality organizations
to conduct a multiyear research study to identify and quantify
PM-10 emissions from agricultural operations and to develop
effective control measures.
Currently available data indicate that replacement of tilling
operations, where feasible, with plug and punch planting and
aerial seeding will reduce dust emissions.
6.7 OPACITY MEASUREMENT
Once a specific PM-10 control strategy has been developed and
implemented, it becomes necessary for either the control agency
or industrial concern to assure that it is achieving the desired
level of control. As stated previously, the control efficiency
actually attained by a particular technique depends on its proper
implementation. This section will discuss opacity measurement as
a means for determining compliance with various regulatory
requirements relating to PM-10 control strategies.
6.7.1 Method for Determining Visible Emissions
Visible emission measurement methods have been adopted by a
number of States as a tool for compliance. Although opacity
observations at the property line have commonly been employed in
earlier fugitive dust control regulations, recent court decisions
in Colorado and Alabama have found that rules of that type are
unconstitutional (failing to provide equal protection). It is
strongly recommended that property-line opacity observations
serve only as an indicator of a potential problem, thus
6-25 September 1992
-------
"triggering" further investigation. Source-specific opacity
determinations, on the other hand, have long been a court-tested
approach to regulation. The following section describes two
States' approach to fugitive dust regulation using visible
emission methods.
6.7.1.1 Tennessee Visible Emission Method—
The State of Tennessee has developed a method (TVEE Method 1)
for evaluating visible emissions (VE) from roads and parking lots
(Telecon, 1984). The following discussion focuses on TVEE Method
1 (Ml) in the technical areas: (1) reader position/techniques,
and (2) data reduction/evaluation procedures. Table 6-3
summarizes the relevant features of TVEE Ml.
As indicated in Table 6-3, TVEE Method 1 specifies an
observer location of 15 feet from the source. In most cases,
this distance should allow an unobstructed view and, at the same
time, meet observer safety requirements.
Ml also specifies that the plume be read at
approximately 4 feet directly above the emitting surface. This
specification presumably results from field experiments conducted
to support the method. It is probably intended to represent the
point (i.e., location) of maximum opacity. While there is no
quantitative supporting evidence, it seems likely that the height
and location of maximum opacity relative to a passing vehicle
will vary depending upon ambient factors (wind speed and
direction) as well as vehicle type and speed.
Implied in the Ml specification that the plume be read
approximately 4 feet above the emitting surface is the fact that
observations will be made against a terrestrial (vegetation)
background. The results of one study using a conventional smoke
generator, modified to emit horizontal plumes, indicated that
under these conditions observers are likely to underestimate
opacity levels. More specifically, the study found that as
opacity levels increased, opacity readings showed an increasing
negative bias. For example, at 15 percent opacity, the observers
6-26 September 1992
-------
TABLE 6-3. SUMMARY OF TVEE METHOD 1 REQUIREMENTS (Ml)
Reader position/techniques
Sun in 140° sector behind the reader.
Observer position ~ 15 ft from the source.
Observer line of sight should be as perpendicular as
possible to both plume and wind direction.
Only one plume thickness read.
Plume read at ~ 4 ft directly above emitting surface.
Individual opacity readings taken each 15 s, recorded to
nearest 5% opacity.
Readings terminated if vehicles passing in opposite
directions create intermixed plume.
Data reduction
2-min time-averages consisting of eight consecutive 15-s
readings.
Certification
Per Tennessee requirements
6-27 September 1992
-------
underestimated opacity by about 5 percent, and at 40 percent
opacity, observations averaged about 11 percent low (Rose, 1984).
Black plumes were underestimated at all opacity levels.
Ml specifies that only one plume thickness be read. It
includes qualifying provisions that: (1) readings terminate if
vehicles passing in opposite directions create an intermixed
plume, but (2) readings continue if intermixing occurs as a
result of vehicles moving in the same direction. Unlike (1), the
latter condition is considered representative of the surface.
The intent here is probably to minimize the influence of
increasing plume density which results from "overlaying" multiple
plumes.
There are two basic approaches that can be used to reduce
opacity readings for comparison with VE regulations. One
approach involves the time-averaging of consecutive 15-s
observations over a specified time period to produce an average
opacity value.
In the development of Ml, the State of Tennessee concluded
that a short averaging period—2 min (i.e., eight consecutive
15-s readings)—was appropriate for roads and parking lots,
because these sources typically produce brief, intermittent
opacity peaks.
Although not specified in Ml, discrete 15-s VE readings from
open sources could be evaluated in a time-aggregating framework.
In this case, the individual observations are compiled into a
histogram from which the number of observations (or equivalent
percent of observation time) in excess of an opacity limit may
then be ascertained. The principal advantage of using the time-
aggregate technique as a method to reduce VE readings is that the
resultant indicator of opacity conditions is then compatible with
regulations that include a time exemption clause. Under time
exemption standards, a source is permitted opacity in excess of
the standard for a specified fraction of the time (e.g.,
3 min/h). The concept of time exemption was originally developed
to accommodate stationary source combustion processes.
6-28 September 1992
-------
Without more detailed supporting information, it is difficult
to determine which of the two approaches is most appropriate for
evaluating VE from open sources. With respect to time-averaging,
statistics of observer bias in reading plumes from a smoke
generator do indicate at least a slight decrease in the
"accuracy" of the mean observed opacity value as averaging time
decreases. In Ml (2-min average), this is reflected in the
inclusion of an 8.8 percent buffer for observational error. This
buffer is taken into account before issuing a Notice of Violation
(Telecon, 1984).
One potential problem with applying time-averaging to opacity
from roads and parking lots is that the resulting average will be
sensitive to variations in source activity. For example,
interpreting one conclusion offered in support of Method 1, it is
likely that under moderate wind conditions a single vehicle pass
will produce only two opacity readings > 5 percent. Averaging
these with six zero (0) readings yields a 2-min value below any
reasonable opacity standard. Yet, under the same conditions with
two or more vehicle passes, the average value will suggest
elevated opacity levels. While there is no information available
on the use of time aggregation for open source opacity, it
appears that this approach would more easily accommodate varia-
tions in level of source activity. For this reason alone, it may
be the evaluation approach better suited to roads and parking
lots.
6.7.1.2 Ohio Draft Rule 3745-17-(03)(B)—
The State of Ohio submitted a fugitive dust visible emission
measurement technigue which the EPA proposed to approve in the
Federal .Register on January 2, 1987. Unlike the Tennessee
method, the Ohio draft rule contains provisions for sources other
than roads and parking lots. Average opacity values are based on
12 consecutive readings. Table 6-4 summarizes the Ohio method;
6-29 September 1992
-------
as can be seen from the table, many features of the Ohio draft
rule are similar to TVEE Method 1. Consequently, the remarks
made earlier in this section are equally applicable here.
6-30 September 1992
-------
TABLE 6-4. SUMMARY OF OHIO DRAFT RULE 3745-17-(03)(B)
Reader position/techniques
Roadways and parking lotsr
Line of vision approximately perpendicular to plume
.direction.
Plume read at - 4 ft above surface.
Readings suspended if vehicle obstructs line of sight;
subsequent readings considered consecutive to that taken
before the obstruction.
Readings suspended if vehicles passing in opposite
direction create an intermixed plume; subsequent readings
considered consecutive to that taken before intermixing.
If unusual condition (e.g., spill) occurs, another set of
readings must be conducted.
All other sources:
Sun behind observer.
Minimum of 15 ft from source.
Line of sight approximately perpendicular to flow of
fugitive dust and to longer axis of the emissions.
Opacity observed for point of highest opacity.
6-31 September 1992
-------
SECTION 7
REFERENCES
American Association of State Highway and Transportation
Officials (AASHTO). 1990. A policy on geometric design of
highways and streets.
American Association of State Highway and Transportation
Officials (AASHTO). 1976. AASHTO Maintenance Manual. 1st
Edition, Washington, D.C.
American Public Works Association (APWA). 1969. Water pollution
aspects of urban runoff. Chicago.
American Society for Testing and Materials (ASTM). 1990. Annual
Book of ASTM Standards, Philadelphia, Pennsylvania.
Arizona DOT. 1975. Soil erosion and dust control on Arizona
highways. ADOT-RS-13 (141) IV.
Bisal, F. and Ferguson, W. 1970. Effect of nonerodible
aggregates and wheat stubble on initiation of soil drifting.
Canadian Journal of Soil Science, 50:31-34.
Bonn, R., et al. 1978. Fugitive emissions from integrated iron
and steel plants. EPA-600/2-78-050, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
Bonn, R., and Johnson, J. D. 1983. Dust control on active
tailings ponds. Contract No. J0218024, U.S. Bureau of
Mines, Minneapolis, Minnesota.
7-1 September 1992
-------
Games, D., and Drehmel, D. C. 1982. The control of fugitive
emissions using windscreens. In: Third Symposium on the
Transfer and Utilization of Particulate Control Technology
(March 1981), Vol. IV, EPA-600/9-82-005d, NTIS
No. PB83-149617.
Changery, M. J. 1978. National Wind Data Index Final Report.
National Climatic Center, Asheville, North Carolina,
HCO/T1041-01 UC-60.
Chepil, W. S. 1952. Improved rotary sieve for measuring state
and stability of dry soil structure. Soil Science Society
of America Proceedings, 16, 113-117.
Chepil, W. S., and Woodruff, N. P. 1963. The physics of wind
erosion and its control. In: A. G. Norman (ed.), Advances
in Agronomy, Vol. 15. Academic Press, New York.
Chepil, W. S., Woodruff, N. P., Siddoway, F. H., and Lyles, L.
1960. Anchoring vegetative mulches. Agricultural
Engineering, 41:754-755.
Climatic Atlas of the United States. 1968. U.S. Department of
Commerce, Washington, D.C.
Courtney, W., and Cheng, L. 1978. Control of respirable dust by
improved water sprays. In: Respirable Dust Control
Proceedings, Bureau of Mines Technology Transfer Seminars,
Bureau of Mines Information Circular 8753, p. 96.
Cowherd, C., Jr., et al. 1974. Development of emission factors
for fugitive dust sources. EPA-450/3-74-037, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
Cowherd, C., Jr., and Englehart, P. J. 1984. Paved road
particulate emissions. EPA-600/7-84-077, U.S. Environmental
Protection Agency, Washington, D.C.
7-2 September 1992
-------
Cowherd, C., and Guenther, C. 1976. Development of a -
methodology and emission inventory for fugitive dust for the
regional air pollution study. EPA-450/3-76-003, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
Cowherd, C., Jr., and Kinsey, J. S. 1986. Identification,
assessment and control of fugitive particulate emissions.
EPA-600/8-86-023, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
Cowherd, C., Jr., Muleski, G. and Kinsey, J. S. 1988. Control
of open fugitive dust sources. EPA-450/3-88-008, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
Cuscino, T., Jr., Muleski, G. E., and Cowherd, C., Jr. 1983.
Iron and steel plant open source fugitive emission control
evaluation. EPA-600/2-83-110, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina.
Duley, F. L. 1958. U.S. Department of Agriculture Agronomy
Handbook, 136, 1-31.
Duncan, M., et al. 1984. Performance evaluation of an improved
street sweeper, EPA Contract No. 68-09-3902.
Englehart, P. J., and Kinsey, J. S. 1983. Study of construction
related mud/dirt carryout. EPA Contract No. 68-02-3177,
Work Assignment No. 21.
Gillette, D. A., et al. 1980. Threshold velocities for input of
soil particles into the air by desert soils. Journal of
Geophysical Research, 54(C10):5621-5630.
Grelinger, M. A. 1988. Gap filling PM-10 emissions factors for
selected open area dust sources. EPA-450/4-88-003, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
7-3 September 1992
-------
JACA Corporation. 1979. Control of air emissions from process
operations in the rock crushing industry. EPA-340/1-79-002,
U.S. Environmental Protection Agency, Washington, D.C.,
p. 15.
Kinsey, J. S., et al. 1983. Study of construction related dust
control. Contract No. 32200-07976-01, Minnesota Pollution
Control Agency, Roseville, Minnesota.
Kinsey, J. S., et al. 1991. Guidance document for selecting
antiskid materials applied to ice- and snow-covered
roadways. EPA Contract No. 68-DO-0123, Midwest Research
Institute.
Larson, A. G. 1982. Evaluation of field test results on wind
screen efficiency. In: Fifth EPA Symposium on Fugitive
Emissions: Measurement and Control, Charleston, South
Carolina.
Lorant, F. I. 1986. Non-point source pollution in urban areas—a
Canadian perspective. IAHS Publication 157 (Monit. Detect
Changes Water Quality Ser.).
Marshall, J. 1971. Drag measurements in roughness arrays of
varying density and distribution. Agricultural Meteorology,
8:269-292.
Midwest Research Institute. 1983. East Helena fugitive dust
controls for paved and unpaved roads. Final Report for Air
Quality Bureau, Department of Health and Environmental
.Services. Helena, Montana.
.Muleski, G. E. 1985. Coal yard wind erosion measurements.
Midwest Research Institute Final Report. Industrial client.
Muleski, G. .£,, and Hecht, D. 1990. Survey of construction
demolition open source regulations and dust control plans.
Final Report USEPA Contract 68-02-4395, WA 48. Research
Triangle Park, North Carolina.
7-4 September 1992
-------
Muleski, G. E., and Cowherd, C. , Jr. 1987. Evaluatiojir-ooDthe
effectiveness of chemical dust suppressants on unpaved
roads. EPA-600/2-87-102, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina.
National Climatic Center. Local Climatological Data. Monthly
summary available for each U.S. Weather Station. Asheville,
North Carolina 28801.
Nickling, W. G., and Gillies, J. A. 1986. Evaluation of aerosol
production potential of type surfaces in Arizona. Submitted
to Engineering-Science, Arcadia, California, for EPA
Contract No. 68-02-388.
Pitt, R. 1983. Urban runoff study program, Humber River,
Toronto. Blue Mounds, U.S.
R. S. Means Company. 1990. Means building construction cost
data-1990. 49th Annual Edition. Kingston, Massachusetts.
Radkey, R. L., and MacCready, P. B. 1980. A study of the use of
porous wind fences to reduce particulate emissions at the
Mohave Generating Station. AV-R-9563, AeroVironment, Inc.,
Pasadena, California.
Rose, T. H. 1984. Evaluation of trained visible emission
observers for fugitive opacity measurement. EPA-60/3-84-
093, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina.
Russell, D., and Caruso, S. C. 1984. The relative effectiveness
of a dust suppressant for use on unpaved roads within the
iron and steel industry. Presented at EPA/AISI Symposium on
Iron and Steel Pollution Abatement, Cleveland, Ohio.
Sartor, J., and Boyd, G. 1972. Water pollution aspects of
street surface contaminants. Report EPA-R2-72-081, U.S.
Environmental Protection Agency, Washington, D.C.
7-5 September 1992
-------
Seibel, R. , 1976. Dust control at a conveyor transfer point
using-foam and water sprays. Bureau of Mines, Technical
Progress Report 97.
Skidmore, E. L,, and Woodruff, N. P. 1968. Wind erosion forces
. in the United States and their use in predicting soil loss.
USDA, ARS, Agriculture Handbook No. 346. 42 pp.
Studer, B. J. B., and Arya, S. P. S. 1988. Windbreak
effectiveness for storage pile fugitive dust control: A
wind tunnel study. Journal of the Air Pollution Control
Association, 38:135-143.
Telecon. 1984. Englehart, P., Midwest Research Institute, with
Walton, J., Tennessee Division of Air Pollution Control,
Nashville, Tennessee.
U.S. Bureau of Mines. 1982. Dust knockdown performance of water
spray nozzles. Technology News, No. 150.
USEPA. 1982. Air quality criteria for particulate matter and
sulfur oxides. U.S. Environmental Protection Agency.
USEPA. 1983. Non-metallic processing plants, background
information for proposed standards. EPA-450/3-83-001a, NTIS
No. PB83-258103. U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
USEPA. 1985. Compilation of air pollution emission factors, AP-
42, Fourth Edition. U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina. Supplement A,
October 1986. Supplement B, September 1988. Supplement C,
September 1990.
USEPA. 1989. OAQPS Control Cost Manual, 4th Edition, Standards
Development Branch, Research Triangle Park, North Carolina.
Volkwein, J. C., Cecala, A. B., and Thimons, E. D. 1983. Use of
foam for dust control in minerals processing. Bureau of
Mines RI 8808.
7-6 September 1992
-------
Westec Services, Inc. 1984. Results of test plot studies^8t
Owens Dry Lake, Inyo County, California. San Diego,e
California.
Woodruff, N. P., and Siddoway, F. H. 1965. A wind erosion
equation. Soil Sci. Soc. Amer. Proc., 29(5):602-608.
Zimmer, R. A., et al. 1986. Field evaluation of wind screens as
a fugitive dust control measure for material storage piles.
EPA-600/7-86-027, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
Zingg, A. W. 1954. The wind erosion problem in the Great
Plains. Trans. Geophysics Union, 35:252-258.
7-7 September 1992
------- |