Compilation of Past Practices and Interpretations by EPA Region VIII
on Air Quality Mining
I. Background
On December 5, 1974, EPA promulgated regulations under the 1970
version of the Clean Air Act for the prevention of significant deter-
ioration of air quality (PSD). These regulations established a pro-
gram for protecting areas with air quality cleaner than the national
ambient air quality standards (NAAQS). The primary mechanism for
implementation of that program was a preconstruction review program
applicable to specific categories of major stationary sources. Nine-
teen source categories were listed in those regulations. Under that
new source review program which has been implemented by EPA, a pro-
posed major facility was reviewed according to the following criteria:
(1) The combined impacts of that source and other new sources in
the area could not exceed prescribed ambient air quality
increments. Increments for total suspended particulates
(TSP) and sulfur dioxide were established and in a given area
are a function of the PSD classification of the area; and
(2) The new or modified source must utilize best available con-
trol technology (BACT).
On August 7, 1977, Congress amended the Clean Air Act and Part C
of the new Act contains specific requirements for the prevention of
significant deterioration.
For the most part the 1977 Amendments were a codification of the
EPA regulations. However, some additional requirements were inclu-
ded. A few of these additional requirements are:
(1) The source category list was expanded to 29 and the Amend-
ments added a general provision requiring applicability to
any new or modified source which will have potential emis-
sions of 250 tons per year;
(2) The air quality increments were revised;
(3) Certain areas were established as mandatory Class I areas and
the Federal Land Managers for these areas were given specific
responsibilities to protect the air quality related values of
the areas; and
(4) One calendar year of ambient air quality monitoring data may
be required to accompany a PSD application.
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The expansion of the applicability of the PSD program has resulted
in the inclusion of fugitive dust sources in the PSD coverage. In
fact, because of the nature of fugitive dust sources, such as surface
mines, the 1977 Amendments have applied the preconstruction review
program to relatively many small operations.
Because of the differences between point (stack) sources and fugi-
tive dust sources in terms of control technology, as well as localized
versus regional air quality impacts, it was necessary for EPA to de-
velop unique criteria in the review of preconstruction applications
for operations which cause fugitive dust. These provisions were cod-
ified in regulations published on June 19, 1978, (43 FR 26388). Since
promulgation of those regulations, EPA Region VIII has received more
than 40 permit applications from companies planning operations which
would cause fugitive dust emissions. During that period, because of
the complexity of the PSD program, particularly with respect to the
unique provisions for fugitive dust sources, numerous questions have
surfaced which need immediate resolution. The following discussions
are intended to address these questions and the manner in which they
were resolved, and are intended to provide insight as to the inter-
pretations by Region VIII staff regarding some portions of the PSD
regulations. Four general areas are addressed:
(1) General - Discussions of the interpretation of certain defin-
itions as they apply to fugitive dust sources and interpre-
tations of other general provisions of the PSD regulations.
(2) Monitoring - Region VIII interpretation of the intent of the
preconstruction/postoperation monitoring requirements as they
apply to operations which cause fugitive dust, and the design
of monitoring programs which have been approved by Region
VIII.
(3) BACT - Region VIII interpretaton of the applicability of the
BACT requirement with respect to fugitive dust and control
practices considered in reviewing pending applications.
(4) Modelinq - Region VIII's current thinking regarding available
models for fugitive dust sources.
II. General Interpretations
During the consideration of permit applications received to date a
number of clarifications and interpretations of the intent of the PSD
regulations with respect to fugitive dust have been necessary. Some
of these involved clarification of the definitions contained in the 40
CFR 52.21(b) of the PSD regulations. Others involved clarification of
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other portions of the regulations and their application to fugitive
dust sources. The following is a discussion of some of the issues
that have needed resolution and the interpretation which was imple-
mented by Region VIII.
(1) Fugitive Dust - Included in this category are overburden and
topsoil removal, grading, exposed soils, and haul roads. Not
included are operations involving the processing of product
or product ore (i.e., coal, uranium ore). The processing of
product includes the emissions resulting from the actual
removal of the product from the earth (e.g., blasting, and
removal of coal from the seam), as well as emissions resul-
ting from the conveying, crushing, screening, storage and
transfer of the product.
(2) Best Available Control Technology - This is usually expressed
as a numerical emission limitation. However, for operations
which cause fugitive dust it is expressed as a set of work
practices designed to minimize, to the maximum extent prac-
ticable, emissions of fugitive dust.
(3) Potential Emissions - Total uncontrolled emissions, including
fugitive dust.
(4) Allowable Emissions - Total controlled emissions. Depending
upon the application of allowable emissions, it may either
include or exclude fugitive dust (See Item I1-5).
(5) Review Criteria - Any source (i.e. mine) with potential emis-
sions greater than 250 tons per year is subject to PSD
review. Potential emissions are computed for al1 facilities
within an operation, including fugitive dust. BACT is
required of all facilities if the total allowable emissions
from all facilities are greater than 50 tons per year or 1000
pounds per day. In this portion of the review, controlled
fugitive dust emissions would be included in the determi-
nation as to whether the allowable emissions exceed 50 tons
per year or 1000 pounds per day. Air quality review, includ-
ing monitoring, modeling, and additional impact analyses, is
required if allowable emissions (excluding fugitive dust
emissions) exceed the above criteria given for BACT. As
described in 40 CFR 52.21(k)(5), the allowable emissions
would not include fugitive dust and the air quality review
could exclude impacts of fugitive dust.
(6) Boundaries - The air quality review need not consider impacts
within the applicant's boundaries or within the boundaries of
neighboring industrial operations. The source boundary is
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generally defined as the permitted area (or area owned by the
applicant) as specified in an approved mininq Dlan. On certain
occasions it may be necessary to define the boundaries in terms
of the leased area. If a well defined mine Plan Boundary does
not exist, then a case-by-case determination of such boundaries
must be made durinn the permit review.
(7) Modifications - A modification is referred to as a channe in
the operation which would increase potential emissions by 250
tons per .year. In the case of a mininq operation an annli-
cable modification would usually consist of an increase in
the production rate above that which existed on Auqust 7,
1977, or above that which is stipulated in a PSD or State new
source permit. Changes in the areas of an operation can also
be considered a modification if there is a net increase in
emissions of more than 250 tons per year. Specifically, for
an operation which has a PSD oerrrit, that permit will stip-
ulate those areas which can be mined without being considered
a modification.
(8) Emission Factors - The state-of-art for emission factors for
fugitive dust is extremely limited at present, and additional
field studies are absolutely necessary. Those factors which
Region VIII believes best represent particulate emissions
from mininq operations are shown in Section IV of this
paper. However, this list is not all inclusive and other
representative emission factors can be used after consul-
tation with Region VIII staff. EPA has recently contracted
Midwest Research Inc. and Pedco-Environmental to perform a
joint study to develop better emission factors for western
surface mining operations. This guideline document will be
updated to incorporate the new emission factors when they
become available in early 1980.
(9) Emission Categories - While the major facilities within a
operation which causes fugitive dust are taken into account
when determining the total potential emissions from the over-
all source, clarification is required concerning a few cate-
gories.
(a) Mobile Sources - Tail pipe emissions are ignored for PSD
purposes.
(b) Construction Emissions - These emissions are not con-
sidered in determinina whether a new or modified source
is subject to the PSD regulation. However, if a PSD
permit is required, the construction phase emissions of
an operation is subject to the BACT requirements.
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(c) Secondary Emissions - In computing potential emissions,
all on-site reentrained dust traffic emissions are
included. In addition, off-site reentrained dust from
hauling product or product ore are considered. However,
reentrained dust from off-site employee traffic is
ignored.
III. Monitoring
Section 52.21(n) of the PSD regulations provides the opportunity
for EPA to require ambient air quality monitoring both prior to sub-
mission of a PSD application and during the operation of the source.
This requirement applies only to a major source whose allowable emis-
sions, excluding fugitive dust, exceed 50 tons per year or 1000 pounds
per day.
The main purpose of this requirement is to assess the air quality
impact of the source and to determine if the source is contributing to
a violation of a national ambient air quality standard. The extent of
air quality data which must be collected is determined by EPA on a
case-by-case basis depending upon the need for data and the represen-
tativeness of the air quality data already being collected or
previously collected in the vicinity of the proposed operation.
Considerations which EPA has used in the review of PSD ambient air
monitoring network reviews are discussed in Appendix A. This internal
checklist may provide useful information for prospective applicants.
As an example, the type of ambient monitoring which is being per-
formed for various reasons by a few large surface mines in the west is
described below:
Preconstruction
For baseline levels, TSP data is collected for one year using
hi-vol samplers at one or more sites in the vicinity of the proposed
mining operations. To provide statistical confidence in the monitored
results, a sampling frequency of once-every-third day should be uti-
lized. State schedules which prescribe some other frequency, repre-
sentativeness of data collected on other less frequent sampling
schedules, availability of electrical power and manpower, and costs
are considerations which influence the choice of an optimum monitoring
frequency. In addition to TSP, one air monitor should be equipped to
provide information on particle size distributon. These data could
provide some insight to the general contribution of very large
particles to high concentrations of TSP. If sophisticated "level two"
diffusion modeling (as described in Section V) will be utilized to
predict ambient impacts, it would be to the applicant's advantage to
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collect continuous meteorological data at one location to collect data
needed as input to the model. Also "event-triggered" precipitation data
would be extremely useful for computing annual emissions where nredic-
tion of emissions is dependent upon precipitation.
Operational
In order to determine the variability of air quality impacts from
mininq activities, TSP data could be recorded on a more frequent basis
than durinq the baseline program at three locations (two in the pre-
vailing downwind direction and one uowind). One of the two downwind
sites should also collect particle size data. In addition, meteor-
ological data similar to that collected in the preconstruction nhase
should be recorded. Collection of these data should allow the mine
operator to be able to better demonstrate the contribution which his
operations are making toward recorded air quality concentrations.
IV. Modeling
The PSD regulations (40 CFR 52.21(1), (k) and (b)(6) require an
air quality impact analysis on the non-fuqitive dust portion of the
particulate matter emissions resulting from mininq activities if the
allowable emissions (excluding fugitive dust) from these sources ex-
ceed 50 tons per year or 1000pounds oer day, whichever is more
restrictive. EPA recommends that the impact analysis make use of
existing atmospheric dispersion models such as those discussed in the
"Guidelines on Air Ouality Models" (EPA-450/2-78-027). If the appli-
cant has access to a model, or models, which are equivalent to or an
improvement over those listed in the guidelines document, for a speci-
fic application, and can demonstrate their equivalence or improvement,
the applicant may use such models pursuant to the requirements of 40
CFR 52.21(m). Departures from the Guideline models must be subject to
public notice and opportunity for public comment.
Because model applications for particulate matter with an appre-
ciable settling, and model verification studies for such applications,
have not reached the same degree of acceptance as for gaseous pollu-
tants, it is recommended that two levels of sophistication be con-
sidered. The first level would be a rather simple approach which
would make use of screeninq techniques using acceptable models in
which the particulate matter would be assumed to behave much the same
as gaseous pollutants. This approach would make use of the commonly
acceptable dispersion models which are applicable for screening tech-
niques as referenced in the "Guidelines." This simple technique would
be expected to provide conservative estimates. If this analysis
demonstrates that the mining operation causes an insignificant impact
(e. g. one-half the controlling increment or less), no additional analysis
would be required. If the analysis shows a significant impact (e. g.
greater than one-half the controlling increment), additional, more
sophisticated modeling techniques may be necessary.
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Simple Gaussian models which consider both point and area sources
would be appropriate for this first level of review. Past practice at
EPA Region VIII has been to often use the EPA Valley Model. The usual
limitations which restrict the use of atmospheric dispersion models
(see Guideline on Air Quality Models) should be taken into consider-
ation in the impact analyses on mining activitie.
The second level of sophistication would require using models not
provided in the referenced guidelines document. Models appropriate
for this more refined analysis should consider fall velocity and
deposition velocity of particles. This approach requires emissions
data not commonly available; i.e., particle size of the point or area
emissions. This information must be provided by the applicant.
Because more sophisticated models are not referenced in the Guide-
lines, it will be necessary for the applicant to review model use with
EPA Region VIII and comply with the public review provisions of 40 CFR
52.21(m) and (r). Those models may range from Gaussian types such as
the Industrial Complex Source Model, ERTAQ, or others, to numerical
models such as Systems Applications, Inc., IBM, IMPACT, Lawrence
Liver-more Lab, SRI, or others.
Finally as discussed in Section II of this policy paper, air qual-
ity impacts will be assessed beyond the mine "permitted area" boun-
dary. Long term and short term simulation models will be required.
Application of the models will limit prediction of concentrations out
to a maximum distance of 50 kilometers and/or when the TSP concen-
tration becomes less than 1 ug/m^ for 24 hour average. However, any
reasonably expected impacts (such as greater than ten percent of the
Class I increment) must be considered for Class I areas regardless of
the above distance and significant criteria.
V. Best Available Control Technology (BACT)
BACT on all emissions from mining activities, both fugitive and
non-fugitive, is required pursuant to 40 CFR 52.21(j) if allowable
emissions (fugitive plus non-fugitive) exceed 50 tons per year or 1000
pounds per day. Under the Clean Air Act Amendments of 1977 and the
revised PSD regulations (43 FR 26388), BACT is to be determined on a
case-by-case basis rather than automatically applying an applicable
federal New Source Performance Standard (NSPS) as was the case under
the previous PSD regulation.
EPA has published general guidelines for determining BACT. (This
guideline document appears as Appendix B.) Case-by-case determin-
ations of BACT must take into account several factors including cost,
energy and technical feasibility. The procedure for determining BACT
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requires first, that the applicant propose in its PSD application air
pollution control systems which the applicant believes represents
BACT. EPA reviews the proposed controls and may request supporting
information and/or considerations of alternative control systems prior
to making a final decision on BACT. Pre-application meetings between
EPA Region VIII and potential applicants have proven to be a useful
tool in helping applicants to define BACT for their particular source
or operation.
Suggested factors that may be considered in a BACT impact analysis
include, but are not limited to: energy consumption; air, water and
solid waste pollution; economic costs; capital availability; geo-
graphical and climatic factors; or the physical characteristics of the
product (e.g., high moisture content).
Economic ratios such as the ratio of total control costs to total
investment costs, cost per unit of pollutant removed, and unit produc-
tion costs may prove helpful in defining the point at which a given
control measure becomes economically infeasible. The Appendix B
guideline discusses the above ideas in more detail.
In response to numerous questions during pre-application meetings
concerning what control practices would constitute BACT for surface
mining operations, we include Table 1. This table summarizes EPA
Region VIII's past practices and experiences with BACT determinations
for previously permitted large surface coal mines (greater than 4 MM
tons per year; and open pit uranium mines. Deviations from this list
of BACT practices may well be expected for smaller operations, oper-
ations in other geographical areas, various precipitation conditions,
and other types of surface mining operations. Again, we stress the
importance of determining BACT on a case-by-case basis considering
environmental, energy and economic factors. TAble 1 does not con-
stitute a definition of BACT for all_ surface mining operations.
Rather, it provides a concrete illustration of what Region VIII has
accepted as BACT for certain operations in areas of the western United
States. For example, baghouses and enclosed storage piles may be
economically infeasible for the small coal mine operator. The BACT
determination can reflect this and allow for alternate schemes of
control.
Table 1 also lists the emission factors and control efficiencies
used in past BACT analyses. The EPA Region VIII office will consider
the use of other emission factors if the applicant can demonstrate
their appropriateness.
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Table 1
Summary of Past BACT Determinations Made by Region VIII for Large
Surface Coal and Uranium Operations
Uncontrolled Emission Factor
Process Operation
1. Topsoll removal
2. Topsoll stock pile
3. Drilling
a. coal
b. overburden
4. Blasting
«*
a.' overburden
b. coal
5. Overburden removal
a. dragline
b. truck/shovel
c. scraper
6. Overburden stockpile
BACT Practice
Range
16 #/scraper hr.(4)
or 0,38 #/yd3 (1)
Best Estimate
Stabilization via either
a. rapid revegetatlon or>
b. mulch or,
c. chemical dust suppressant* or^
d. establish wind breaks
Use of bag type collector on air drill,
or water injected
a. Minimize area to be blasted
b. Prevent overshooting
14,2
25.1
0.22 #/hole (i
-1.5 #/ho1e (l
85.3 #/blast(l
78.1 #/blast(l
a. Minimize fall distance
of material
Stabilization via either
a. Temporary vegetation or,
b. Mulch or,
c. Chemical dust suppressant*
.0056 - .053 #/yd3 (1)
BACT Contro
Efficiency
75%
85*
85%
50%
90%
f(area blasted)
f(amount of
blasting)
.037 #/ton (1)
16 #/scraper hr.(4)
soil loss equation
** (3)
75%
85%
85%
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Process Operation
7. Overburden shaping
Table 1
BACT - Mining
BACT Practice
Uncontrolled Emission Factor
Range Best Estimate
BACT Contro
Efficiency
a. Leave ridges with
K = 2 - 5
b. Establish wind breaks
c. Orient piles perpendicular
to prevailing wind
d. Rapid revegetatlon (I.e. within one growing season)
e. Minimize spoil pile area
soil loss equation**
(3)
8. Product removal
a. Coal-Truck/shovel
Coal-Front end loader
b. Uranium
Minimize Fall Distance
0.0035-0.014 #/ton(1)
0.12 #/ton (1)
0.05 #/ton (4)
9. Product dumping
a. Coal-bottom dump
Coal-end dump
b. Uran1um-end dump
10. Product storage
a. Coal
wind erosion from
open pile
a. Negative pressure or,
b. Spray system on dumped
material
a. Enclosed
0.005-0.027 #/ton (1)
0.007 #/ton (1)
0.04 #/ton (4)
*1.6 u #/acre hr (1)
where u = wind speed, m/sec
8555
50*
99%
b. Uranium
a. Pile wetting
****
50%
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^ble 1
BACT - Mining
Process Operation
24. Miscellaneous
BACT Practice
Uncontrolled Emission Factor
Range Best Estimate
a. Extinguish smoldering or
burning areas In the mine
b. Chipping and mulching of
vegetative material;removal
from mine site rather than
open burning
c. Minimize all haulage distances
d. Prevent overloading of trucks
e. Covered haul trucks 1f haulage
1s on a public highway
BACT Control
Efficiency
100%
f(amount
burned)
f(VMT)
f(present
practice)
f(VMT)
* Note ~ Dilution ratio of dust suppressant, rate of application, and frequency of application is important.
An example for Coherex 1s shown. This example 1s provided for guidance only. Mention of trade names
does not mean endorsement of any material. Use of other suppressants shall meet equivalent specifi-
cations. Deviations from the specifications below shall be justified on a case-by-case basis, based
upon data submitted by the applicant. Also, 1t 1s anticipated that the PSD permit condition may need
to be revised upon adequate showing by the applicant or by the permitting authority.
Haul roads preparation
Access roads preparation
Road maintenance
Dilution of Coherex
1:4
1:4
1:10
Rate of application Frequency of Application
Disturbed areas not subject 1:10
to vehicles
1 gal/yd,
1 gal/yd2
1/2 gal/yd2
1/2 gal/yd2
Initial
Initial
Once per month when the number of
days when rainfall does not exceed
0.01 1n. = 10 days
Initial
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** Note — From Reference 3 Universal soil loss equation Is E.- 0.025 1KCLV
where E ¦ tons of suspended particulate per acre per year
I « soil erodlblHty factor
K ¦ soil ridge roughness factor
C = localized climate factor
L » field width
V » vegetative cover
*** Note — From Reference 2 E « 0
.6(n.81s)|_LUl65-W) . /,$ /365-M)
30)1.365 J (jss~J
where s ns11t content of road 1n percent
S ¦ vehicle speed In mph
W ¦ mean annual! (number of days with * 0.01 Inches of rain)
Corrections may be applied for vehicle speed and number of vehicle tires.
An alternative method Is to use the following:
E ¦5-9 Reterence 6
where E a #/VMT
s ¦ silt content In percent
S » average vehicle speed; mph'
W a average vehicle weight, tons
d » dry days per year (number of„davs.less than n.fil Inches. Gf rain)
****
E " 0-05^^5^(90) (tXon Reference 6
where s ° silt content In percent
d ° dry days per year
D ¦ duration of material storage, days
f ¦ % of time wind speed exceeds 12 mph.
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Table 1
BACT - Mining
Process Operation
16. Conveyors
a. Fully covered
b. Partially covered
17. Transfer points
18. Uranium
Crushing and
Screening
19. Coal crushing
a. Primary
b. Secondary
20. Coal Screening
PACT Practice
Eully Covered
a. Enclosed and vent
to baghouse or equivalent
b. Ducting to a central
baghouse
Uncontrolled Emission Factor
Range Best Estimate
DACT Control
Efficiency
Baghou& or equivalent
Baghouse or equivalent
Baghouse or equivalent
21. Coal Cleaning
a. Thermal dryer
b. Pneumatic cleaning
@9-10%
@8%
@6%
H20,E =
\E=
" »E=
0.002 #/ton
0.040 #/ton
0.16 #/ton
100%
90%
,0.2 #/ton (4)
for all conveyors 99%
and transfer points 20% opacity
99.0% and
0.01 gr/acf
20% opacity
(5)
0.02 tifton (4)
0.06 #/ton (4)
0.1 #/ton (4)
0.031 gr/dscf
0.018 gr/dscf
99.0% and
0.01 gr/acf
99.0% and
0.01 gr/acf
99.0% and
0.01 gr/acf
NSPS
NSPS
22. Transportation
Bus service
f(VMT)
23. Construction a. Chemical dust suppression of all 50%
roads and disturbed areas
b. Gravel parking lots 50%
c. Confine traffic to specified roads 100%
d. Minimize area of land disturbed 100%
e. Prewater areas to be disturbed 50%
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BACT - Mining
Process Operation
11. Product loading
a. Coal load Into silo
Coal load out from
silo
b. Uranium
12. Haul roads
13. Access roads
a. Jf public
b. if controlled by
operator
14. Road maintenance
BACT Practice
15. Disturbed areas
a. Baghouse on s1lo(
b. Retractable chute on load out,
c. Minimize no. of openlogs
d. Spraying of coal 1n cars
Uncontrolled Emission Factor
Range Best Estimate
0.0002 #/ton (l)
BACT ControF
Efficiency
a. Speed control, and
b. Chemical stabilization
worked Into road*
c. Restrict off road use
955?
(f.05 #/ton (4)
(2)
E =
a. Paving or equivalent
stabilization
b. Speed control, and
c. Restrict off road use
a. Removal of loose debris,
grading
b. Chemical stabilization of
roadbed after grading*
Stabilization via either
a. Chemical dust suppressant*r or
b. Mulch,or
c. Revegetatlon within one growing season, or5
d. Minimize area disturbed
(0.6)(0.81s)
30
Ci 365-wt**
(2)
f (sDeed)
loot
85 - 100*
f(speed)
100*
32 #/road
grader hour
(4)
Soil loss equation**
03)
85%
85*
75%
f(area)
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Refei
(1) f Fugitive Dust from Coal Mines, EPA 908/1-78-003, February
\ Region VIII, Denver, Oolorado
(2) (on of Air Pollutant Emission Factors, AP-42, Second
£
(3) G Wind Erosion Control on Cropland in the Great Plains States,
C Turelle, USDA-SCS, July 1964
(4) Evi of Fugitive Dust Emissions from Mining, prepared by PEDCO
fc:RL-Cin, June 1976
(5) 0R)03 "Correlation of Radioactive Waste Treatment Costs and
tftnmental Impact of Waste Effluents in the Nuclear Fuel Cycle
Establishing as Low as Practicable Guides Milling of
Unes" by Oak Ridge National Laboratory, May 1975
(6) Fuinrissions From Integrated Iron and Steel Plants, EPA - 600/2-78-
Mat by R. Bohn, et al, Midwest Research Institute
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APPENDIX A
PSD AMBIENT AIR MONITORING PLAN
EVALUATION CHECKLIST
Through sections 165(a)(2) and (e) of the Clean Air Act, Congress imposed
on the owner or operator of a proposed major source, who submits a PSD applica-
tion after August 7, 1978, the task of gathering and analyzing air quality
monitoring data for inclusion in the application. Since the PSD review now
includes a review against the applicable National Ambient Air Quality Standards
(NAAQS) the focus of the preconstruction monitoring requirements is on obtaining
reliable data for making that determination. The air quality monitoring as-
sociated with this effort must adhere to EPA's monitoring procedures in effect
at the time of the monitoring. Accordingly, we have attached for your information
a checklist completed by the Region VIII EPA staff as part of our evaluation
of your proposed PSD ambient air monitoring plan. However, this evaluation
does not address whether the proposed preconstruction monitoring is actually
required. This is because sources, under certain conditions, are not required
to perform preconstruction monitoring if such factors as projected emission
levels, adequacy of nearby data, projected air quality impact, etc., indicate
such monitoring is not necessary. If you believe such conditions exist, it is
recommended that you submit documentation supporting this decision to this
office in place of a monitoring plan.
The checklist was developed from the guide!ines included in the attached
EPA document entitled "Ambient Air Monitoring Guidelines for Prevention of
Significant Deterioration," EPA-450/2-78-019 and the proposed requirements
outlined in Appendix B (pp. 34913-34916) of the attached August 7, 1978,
Federal Register. Please note that Appendix B is simply a restatement of the
quality assurance section contained in the above mentioned guideline document.
However, you should be aware that the quality assurance requirements set forth
in Appendix B, as proposed, may be revised prior to final promulgation. Upon
final promulgation our checklist will be modified to reflect these changes.
For this reason, if our review of your air monitoring plan is completed prior
to the promulgation of Appendix B, you may wish to resubmit your plan to this
office for a reevaluation. If you do not resubmit your plan, it is important
that you carefully review the monitoring requirements in effect at the time
your preconstruction monitoring is initiated so that the data generated through
this effort will be considered acceptable by the appropriate PSD permitting
authority.
Because most preconstruction monitoring will take place in areas relatively
unaffected by existing point source emissions, our review has not included a
detailed evaluation of monitoring site locations. However, we would recommend
that if you plan to undertake postconstruction (operational) monitoring, the
preconstruction sites should be carefully selected so that they may be easily
incorporated into the postconstruction monitoring program.
Note: Copies of EPA-450/2-78-019 and the finalized Appendix B
(Quality Assurance Reauirements for PSD Air Monitoring,
44FR27582,Mav 10, 1979) are available from the Region VIII EPA
Offi ce.
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2
In many cases, monitoring plans submitted to this agency for review
do not contain sufficient information for our staff to make an accurate
determination of acceptability. For this reason satisfactory ratings are
given only for those items where sufficient information has been provided
to allow for a reliable assessment. It is also recommended that you reevaluate,
modify and resubmit to this office information concerning those items indicated
as being other than satisfactory.
We wish to reemphasize that our evaluation is being made solely on the
basis of the proposed ambient air monitoring plan you submitted. However,
the final determination of data acceptability will be based on the monitorinq
activities and quality assurance practices indicated in your data reports as
actually being implemented during the course of the monitoring effort.
If you have additional questions concerning our review of this monitoring
plan, please contact this office at 303-837-4261.
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PSD
AMBIENT AIR MONITORING
NETWORK REVIEW
Company Name
Company Address
Source Type
Plant Location
Date Submitted (S&A)
Date Reviewed (S&A):
Evaluated by (S&A):
Date Reviewed (AHMD)
Evaluated by (AHMD):
Remarks:
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TABLE OF CONTENTS
PAGE
I. Network Description 1
(Location and Number of Monitoring Sites and Pollutants Monitored)
II. Monitoring Site Description and Operation 2
(Probe Siting, Instrumentation, Duration and Frequency of Monitoring)
III. Quality Assurance Program 5
(Appendix B - August 7, 1978, Federal Register Proposal)
IV. Meteorological Monitoring 11
V. Data Reporting 13
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I. NETWORK DESCRIPTION (AHMD)
Region VIII
Assessment
Revi ew
Comments
A. Pollutants Monitored
B. Number of Monitoring Sites
C. Location of Monitoring Sites
Legend: (S) Satisfactory
(U) Unsatisfactory
(MIN) More information needed from source before an adequate assessment can be made.
-1-
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Ila. PROBE SITING (S&A)
TSP
a. Vertical placement
b. Spacing from obstructions
c. Spacing from roads
d. Other consideration
SO2
a. Horizontal vertical
probe placement
b. Spacing from obstructions
CO
a. Horizontal and vertical
b. Spacing from obstructions
c. Spacing from roads
(See pp. 17-26 of "PSD Monitoring
Guidelines"; EPA-450/2-78-019)
Site Site Site Site Remarks
-3-
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OZONE
a. Horizontal and vertical
probe placement
b. Spacing from obstructions
c. Spacing from roads
NO?
a. Horizontal and vertical
b. Spacing from obstructions
c. Spacing from roads
Site Site site Remarks
-4-
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III. QUALITY ASSURANCE PROGRAM (SKA)
(Section Numbers Refer to
August 7, 1978 Federal Register Proposal
Appendix B - Dp 34913-34916)
Region VIII Review
Assessment Consents
A. Activities to Demonstrate Within Control
Conditions for Continuous Monitors (2.1)
1. Calibration requirements (2.1.2)
a. Calibration curves generated using zero
plus a minimum of 5 points equally spaced
over analyzer range.
b. Initial calibration upon installation.
c. Recalibration rationale.
(1) When span check control limits are
exceeded.
(2) After instrument repair or replacement
of major components.
d. NBS Traceability Protocol (2.1.2)
(1) Establish NBS traceability between gaseous
calibration standards and NBS Standard
Reference Material (SRM).
2. One point span check requirements (2.1.3)
a. Frequency - at least once per week per analyzer
-5-
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Span check concentration -
(SO2, NO2, O3 - between 0.08 and 0.10 ppm;
CO-between 8 and 10 ppm and zero checks for
all analyzers). (Zero check is a Region VIII
requirement.)
Acceptance limits
(SO2, NO2, and O3 limit + 0.025 ppm;
CO 1imit + 2.0 ppm).
Corrective action
(1) If control limit is exceeded, the
instrument is to be taken off-line
until after problems are corrected.
(2) Recalibration (zero + 5 points) -
performed after analyzer is brought
back on-line.
B. Activities to Demonstrate Within Control Conditions
For Total Suspended Particulate (TSP) Reference
Method (Hi-Vol Sampler) (2.2)
1. Initial Sampling Flow Rate Check (2.2.1)
a. Must be within ± 15 percent of established
average initial flow rate for each sampling
day. (Average initial flow rate is
established based on the average of the
first four initial flow rate measurements
performed after each calibration).
b. If limit is exceeded recalibrate or take other
corrective action (see section 2.2.4 pages
10 and 11, Vol. II - Redbook).
c.
-6-
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2. Initial Calibration - (Region VIII Requirement)
a. Performed at start-up.
b. Calibration curve established using
a minimum of 5 Doints (if a Hi-Vol
sampler has a flow control device
the flow controller must be dis-
connected before the sampler is
calibra ted).
3. Exposed Filter Reweighing (2.2.1)
a. Reweigh a sample of randomly
selected exposed filters.
b. Acceptance limits ± 5.0 mg or
less of original weight of
exposed filter.
c. Corrective action - If acceptance
limit is exceeded entire filter
lot reweighed. (See part 8.1.3 of
section 2.2.8 of Volume II - Redbook).
4. Recalculation of TSP Concentrations (2.2.1)
a. Recalculate a sample of randomly selected
TSP values (ug/m3). Values must agree.
b. If values don't agree all calculations
for the lot are checked and corrected
as necessary. (See part 8.1.4, of
section 2.2.8 of Volume II - Redbook).
-7-
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C. General Description of Activities to Assess
Monitoring Data Precision and Accuracy
1. Precision calculated from periodic checks
made by routine operator/analyst during
normal operation.
2. Accuracy is calculated from audits.
Audits - Independent assessment achieved
using different personnel, audit standards
and equipment from those routinely used
during method calibration. As a minimum
different personnel and audit standards
are to be used. Preferred that different
auditing organization be used.
3. Recommended that quality control charts be
used to establish control limits for precision
and accuracy data in that Federal Register
1imits are 1iberal.
D. Activities to Assess Monitoring Data Precision
and Accuracy for Continuous Methods (2.4)
1. Assessment of data for precision (2.4.1).
a. Weekly one point span data for each
analyzer used to calculate precision
in accordance with (3.1.1).
2. Assessment of data for accuracy (2.4.2).
a. Independent audit data used to
calculate accuracy in accordance
with (3.1.2).
-8-
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1.
Frequency - Once per sampling
quarter for each analyzer operated.
2. Audit point - Five point audits
(S02, NO2 and O3 - 0.05, 0.10, 0.20,
0.30, 0.45 ppm all ± o.Ol ppm; CO - 5,
10, 20, 30, 45 ppm all i 1 ppm)
3. Concentration of audit gases
determined Independently using
NBS traceable standards different
from those used to calibrate the
analyzers being audited.
Activities to Assess Monitoring Data Precision
and Accuracy for Total Suspended Particulate
(TSP) (2.5)
1. Assessment of data for precision (2.5.1).
a. Precision determined from collocated
sampler data.
1. Number - At least one collocated
sampler.
2. Siting - At highest exoected 24-hour
pollutant concentration.
3. Location - Samplers located at same
elevation approx. 3 meters apart with
same roof orientation.
4. Designation - One samoler randomly
designated as official sampler with
same identity maintained thereafter.
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5. Operation - Collocated sampler
operated every third day (continuous
daily sampling) or once per week (for
less frequent sampling). All aspects
of operation, maintenance, calibration
are the same for both samplers.
Assessment of data for accuracy (2.5.2)
a. Accuracy determined bv auditing
a portion of the measurement process
(flow rate).
1. Frequency - Once per sampling
quarter for each sampler.
2. Equipment - Reference flow device
(orifice having five different
resistance plates).
3. Procedure - Obtain five different
flows using resistance plates and
calculate accuracy from difference
in resistance plate values and
measured sampler values.
-10-
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IV. METEOROLOGICAL MONITORING (AHMD)
(Section Numbers Refer to "PSD Monitoring Guidelines"; EPA-450/2-78-019)
Region VIII Review
Assessment Comments
A. Data Required (4.1)
B. Exposure of Meteorological Instruments (4.2)
C. Meteorological Instrumentation - Specifications
1. Horizontal wind systems (5.2.1)
2. Vertical wind systems (5.2.2)
3. Wind Fluctuation (5.2.3)
4. Vertical temperature difference (5.2.4)
5. Temperature (5.2.5)
6. Humidity (5.2.6)
7. Radiation - solar and terrestrial (5.2.7)
8. Mixing height (5.2.8)
9. Precipitation (5.2.9)
10. Visibility (5.2.10)
a. Instrument specifications
b. Number of sites
c. Location of sites
d. Target views
-11-
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D. Quality Assurance for Meteorological Data (7.0)
1. Completences of data - At least 90 percent
retrieval for each variable measured.
2. Calibration - Upon installation and at least
every 6 months thereafter.
3. Audits.
a. Independent - Audit performed by someone
other than normal operator.
b. Frequency - Within 60 days of start-up;
approximately every 6 months thereafter;
within 30 days of termination of measure-
ment program.
-12-
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V. DATA REPORTING (S&A)
Review
Comments
A. Quarterly Reports
1. National Ambient Air Quality Standards (NAAQS)
Violations - Report date, time, location and
concentration (with applicable averaging
times, units, etc.) for all NAAQS violations
measured during the reporting period.
2. Data Summary - Submit frequency distribution
for each pollutant concentration measured at
each site.
3. Data Completeness - Include percent data
completeness for each pollutant at each site.
4. Retention of Records - Applicant retains all
strip charts, log books, and other records
from each site and makes available upon
request including all data needed to
calculate precision and accuracy.
5. List of Deviations - Applicant submits with
Quarterly Data Report deviations between
proposed monitoring QA plan and QA
activities actually implemented.
Region VIII
Assessment
-13-
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5. Quality Assurance - Precision and Accuracy
Calculations (section numbers refer to
August 7, 1978 Federal Register Proposal;
Appendix B - pp 34914 - 34916)
a. Calculation for Continuous Methods (3.1)
(1) Single Instrument Precision (3.1.1)
(a) Calculate from weekly span checks,
excluding span data invalidated as
a result of excessive span drift.
(Described in section 2.1.3).
(b) Quarterly average percent
difference (dj) reported for
each analyzer.
(c) Quarterly standard deviation (sj)
reported for each analyzer.
(d) Copy of "Data Assessment Report
for PSD Air Quality Data - Part I"
(Table 3.3.1).
(2) Single Instrument Accuracy (3.1.2)
(a) Calculated from the results of
independent audits (described
in section 2.4.2).
(b) Quarterly average percent difference
(dj) reported for each analyzer.
(c) Quarterly standard deviation (sj)
reported for each analyzer.
(d) Copy of "Data Assessment Report for
PSD Air Quality Data - Parts I and II"
(Table 3.3.1).
-14-
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Calculation for TSP Method (3.2)
(1) Single Instrument Precision for TSP (3.2.1).
(a) Calculated from collocated sampler
data (described in section 2.5.1).
(b) Quarterly average percent difference
(dj) reported for all paired measure-
ments.
(c) Quarterly standard deviation (sj)
reported for each collocated site.
(d) Copy of "Data Assessment Report
for PSD Air Quality Data - Part I"
(Table 3.3.1).
(2) Single Instrument Accuracy for TSP (3.2.2)
(a) Calculated from the results of
independent audits (described in
section 2.5.2).
(b) Quarterly average percent differ-
ence (dj) reported for each sampler.
(c) Quarterly average standard deviation
(sj) reported for each sampler.
(d) Copy of "Data Assessment report for
PSD Air Quality Data - Parts I and
II (Table 3.3.1) (Report known and
measured flow rates for each
resistance plate for each sampler
in Table 3.3.1 Part II).
-15-
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Annual Reports
1. Annual Report includes fourth quarter data as well as
a summary of data collected during previous 12 months.
-16-
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APPENDIX B
GUIDELINES FOR DETERMINING
BEST AVAILABLE CONTROL TECHNOLOGY (BACT)
DECEMBER 1978
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
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GUIDELINES FOR DETERMINING BEST AVAILABLE
CONTROL TECHNOLOGY (BACT)
INTRODUCTION
The 1977 Clean Air Act Amendments establish more restrictive
conditions for the approval of pre-construction permit applications under
the Prevention of Significant Deterioration (PSD) program. One of the
new requirements is for best available control technology (BACT) to be
~
installed for all pollutants regulated under the Act. Under the revised
Act, BACT is to be determined on a case-by-case basis rather than auto-
matically applying an applicable Federal New Source Performance Standard
(NSPS), as was the case under the previous regulation. Concern has been
expressed that these determinations should be consistent from area to
area. In the context of case-by-case BACT, consistency does not ne-
cessarily mean that a new facility in one area will have an identical
emission limit as the same type of facility in another area. Consis-
tency means that a consistent approach is used in determining BACT and
that the impacts of alternative emission control systems are measured by
the same set of parameters, although evaluation of specific parameters
is done on a case-by-case basis.
PURPOSE
This guideline is intended for use by (1) EPA Regional Offices in
determining BACT during the interim period before the States adopt
*Pollutants subject to National Ambient Air Quality Standards, Standards
of Performance for New Stationary Sources, National Emission Standards
for Hazardous Air Pollutants, and Emission Standards for Moving Sources.
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2
State Implementation Plan (SIP) provisions for implementing the PSD
program, (2) by States in writing PSD regulations or determining BACT
and (3) by individual sources in preparing PSD permit applications.
The purpose of the guideline is to provide the framework for a con-
sistent approach to determining BACT. The emphasis is on the types
of data which should be required in a pre-construction permit applica-
tion and how the data should be used in order to determine BACT. The
guideline addresses the technological question of whether the emission
control system proposed in the permit application represents BACT or
whether a more stringent level of emission control is appropriate
considering available technology and economic, energy, and environmen-
tal impacts. The guideline assumes accomplishment of all other air
quality review requirements including, for example, the requirement
that air quality standards and appropriate PSD increments are met,
stack heights are appropriate, and siting is acceptable.
In accomplishing this purpose, the guideline lists a number of
factors which can be considered in assessing energy, environmental, and
economic impacts. While the full list represents the magnitude of the
analysis that could be required for a very large and complex source, many
of these factors will not be relevant to the typical BACT review. The
inclusion of any factor should be based on its relative merit consid-
ering such influences as source size, nature of the process and control
options, and local conditions. It is the clear intent of EPA not to
require an analysis of the full proportion described herein for small
sources or for the use of conventional control equipment whose impacts
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3
are well established. In short, the BACT analysis should be held to a
minimum with the depth of analysis being dependent on the difficulty of
the decision.
PHILOSOPHV OF BACT
The primary purpose of BACT is to optimize consumption of PSD air
quality increments thereby enlarging the potential for future economic
growth without significantly degrading air quality. The Act places the
responsibility of determining BACT with the State once a PSD SIP revision
is approved. The BACT decision is to take into account energy, environ-
mental, and economic impacts and other costs associated with application
of alternative control systems. This case-by-case approach allows
adoption of improvements in emission control technology to become widespread
more rapidly than would occur through the uniform Federal new source or
hazardous emission standards. In setting the NSPS, for example, emission
limits are selected which can reasonably be met by all new or modified
sources in an industrial category, even though some individual sources
are capable of lower emissions. Additionally, because of resource
limitations in EPA, revision of new source standards must lag somewhat
behind the evolution of new or improved technology. Accordingly, new or
modified facilities in some source categories may be capable of achieving
lower emission levels that NSPS without substantial economic impacts.
The case-by-case BACT approach provides a mechanism for determining and
applying the best technology in each individual situation. Hence, NSPS
and NESHAPS are Federal guidelines for BACT determinations and establish
minimum acceptable control requirements for a BACT determination.
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4
Where Federal standards do not exist, guidance on wel1-control!ed sources
is available through the OAQPS clearinghouse (discussed later).
A critical decision in the BACT analysis is the relative weight
assigned to the energy, environmental, ana economic impacts. Congress
implied that this decision should be made by the State, tnus allowing
some flexibility in emission control requirements depending on local
energy, environmental, and economic conditions and local preferences.
For example, in an area with unusually high unemployment, the economic
impacts may be weighted more heavily if the application of a strict BACT
emission requirement would reduce production or jobs. On the other
hand, if visibility protection is a major value of the area, then
environmental impacts could be weighted more heavily. This flexible
approach allows the permitting authority to consider a number of local
factors (for example the size of the plant, the amount of the air
quality increment that would be consumed, and desired economic growth
in the area) in deciding on a weighting scheme. State judgment and
the Federal emission standards are the foundations for the BACT deter-
mination. Accordingly, EPA does not consider it appropriate to assign
nationally applicable weighting factors in this guideline.
GENERAL GUIDELINES
The recommended approach to determining BACT is to place on the
applicant the responsibility for presenting and defending the technology
selection.* This approach recognizes that the applicant is best
suited for assessing the costs, environmental residuals, and energy
*Preliminary meetings between the applicant and the permitting authority
are encouraged as a means of promoting efficiency in the review process.
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5
penalties associated with alternative control options as they apply
to his processes. The permit application shoxild contain the following
elements relative to BACT:
(1) Proposal of a control system representing BACT. 3ACT should
address control of each emission point at a facility, including fugi-
tive process, fugitive dust, and stack emissions. Technology selection
should consider application of flue gas treatment, fuel treatment, and
processes or techniques which are inherently low-polluting. In no
circumstance should a system be proposed for any emission point unless
it is at least as stringent as the applicable SIP or Federal emission
requirement (whichever is more stringent). In cases where technolog-
ical or economic limitations on the application of measurement techniques
would make the imposition of an emission standard infeasible, a design,
operating, or equipment standard may be established.
(2) Presentation of alternative systems that could achieve a
higher degree of emission control. For each pollutant, the BACT permit
application should present control alternatives which have greater control
capabilities than the system proposed as BACT and which have been used or
proposed for the same or similar applications. In some cases, the BACT
decision may require a trade-off of control among pollutants. That is,
a technology may do slightly worse in controlling one pollutant, but do
significantly better in controlling another air, water, or solid waste
residual. Such alternatives should not be excluded from consideration,
but in justifying BACT for a given pollutant only those alternatives
which have greater control capabilities for that pollutant need be
presented in the permit application.
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6
¦ If no better control technology is available for an emission point,
then such finding should be stated and supported, and no further analysis
is required. Other equipment with similar control capabilities need not
be presented (e.g., a baghouse versus an equivalent ESP at a particulate
emitter). Unrealistic alternatives need not be presented such as placing
in series control equipment which is normally used alone (e.g., an ESP
followed by a baghouse). In some cases, a better control technology may
be available for a general type of operation, but unique processing
equipment or procedures may create a valid technical reason which would
preclude its selection as BACT. Such situations should be fully supported.
(3) Defense of the BACT selection. The BACT selection for a parti-
cular pollutant is defended by demonstrating that each alternative control
system (representing a more stringent level of control for that pollutant)
would cause unreasonable adverse energy, environmental, or economic impacts.
The rationale for rejecting each alternative should be presented in the
form of an incremental analysis of the impacts of each alternative
system relative to the proposed BACT system. Relevant energy, environmental
and economic impacts are described below.
IMPACT ANALYSIS
This section outlines the types of impacts that should be recognized
by the permitting authority as relevant issues in assessing the energy,
environmental, and economic impacts of alternative control systems. For
instance, if an applicant wishes to reject an alternative control system,
he would do so by demonstrating the adverse impacts which would result
from the selection of that alternative system. This section lists
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7
specific energy, environmental, and economic impacts which may be addressed
in this impact analysis and explains the data requirements for documenting
an adverse impact. Each of the factors discussed below need not be
addressed in every permit application. Rather this guideline presents a
set of potential impacts any number of which may be addressed in a
permit application depending on the individual situation. For example,
even though a control system may produce solid waste by-products, such
impacts need not be presented in the PSD permit application unless the
applicant wishes to use solid waste impact as an argument against selection
of a particular control alternative as BACT.
In general, the BACT analysis should focus on the direct (on-site)
impacts of alternative control systems. Indirect energy or environmental
impacts are not required but may be considered where such impacts are found
to be significant and well quantified. Indirect energy impacts include
such impacts as energy to produce raw materials for construction of
control equipment, increased use of foreign oil, or increased oil use in
the utility grid. Indirect environmental impacts include such consider-
ations as pollution at an off-site manufacturing facility which produces
materials needed to construct or operate a proposed control system.
Indirect impacts will generally not be considered, in the BACT review,
since the complexity of consumption patterns in the economy makes those
impacts difficult to quantify. For example, since manufacturers purchase
capital equipment and supplies from many suppliers, who in turn purchase
goods from the other suppliers, accurate tracing of indirect impacts may not
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8
be possible. Raw materials may be needed to operate control equipment,
and suppliers of these resources may change over time. Similarly, it
generally will not be possible to determine specific power stations and
fuel sources which would be used to satisfy electrical demand over the
lifetime of a control device.
Duplicative analyses will not be required in preparing the 8ACT
permit application. Any studies previously performed for Environmental
Impact Statements, water pollution permits, State New Source Review, or
other programs may be used when appropriate to demonstrate an adverse
energy, environmental,'or economic impact.
These guidelines are applicable to both new and modified sources.
Where appropriate, however, the review may consider any special economic
or physical constraints which might limit the application of
certain control techniques to a modification project. That is, the level
of control required for a process undergoing modification or reconstruction
may not be as stringent as that which would be required if the same pro-
cess were being constructed at a grass-roots facility. Such findings,
however, must be made on a case-by-case basis by the permitting authority
considering the relevant economic and environmental impacts.
The following discussion, under each of three headings of energy,
environmental, and economic impacts, lists and briefly describes a number
of factors which may be addressed in the respective impact analyses. These
factors are guidelines only and are not intended as an exclusive list of
considerations for BACT. Some of these factors may not be appropriate
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9
in all cases, while, in other instances, factors which are not included
here may be relevant to the BACT determination. The guideline does not
address the evaluation of each factor nor the weighting of any factor
relative to another. Such determinations should be made on a case-by-
case basis by the permitting authority. For purposes of this discussion,
terms such as "emission control system" or "BACT system" refer to design,
equipment, or operating standards and non-polluting processes as well as
flue gas control equipment.
I. Energy Impact
Energy impacts should address energy use associated with a control
system and the direct effects of such energy use on the facility and the
community. As noted earlier, indirect energy impacts (such as energy to
produce raw materials for construction of control equipment) are not
required but may be considered if the permitting authority determines, based
on a showing by the applicant, that the impact is significant and that
the impact can be well quantified. Some specific considerations for
energy impacts are presented below.
A. Energy Consumption
The amount, type (e.g., electric, coal, natural gas), and source
of energy required by each alternative emission control system should
be identified and compared to the quantities and types of energy re-
quired by the proposed BACT system. In analyzing for energy consumption,
various alternatives can be compared in terms of a) energy consumption
per unit of pollution removed (for example, Btu/ton hydrocarbon removed)
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10
and b) energy consumption versus the portion of the remaining PSD
increment which is preserved for future growth. If such comparisons are
made, they should be computed on both an overall and an incremental basis.
3. Impact on Scarce Fuels
The type and amount of scarce cuels (e.g., natural gas, distillate
oil) which are required to comply with each alternative control require-
ment should be identified and compared with the BACT requirement. The
designation of a scarce fuel may vary from area to area, but in general
a scarce fuel is one which is in short supply locally and can better be
used for alternative purposes, or one which may not be reasonably
available to the source either at present or in the future.
C. Impact on Locally Available Coal
Alternatives which require the use of a fuel other than locally or
regionally available coal should be discouraged if such a requirement
causes significant local economic disruption or unemployment.
D. Energy Production Impacts (electric utilities)
The 1977 Act Amendments imposed more stringent BACT requirements,
and may affect electric utility units that were well along in the
planning process prior to adoption of EPA regulations in June 1978.
Where the start-up of the more stringent PSD program would result in
construction delays for these units, the BACT determination may consider
such impacts. The impact of delay plant operation should be assessed
in terms of reserve capacities, system reliability, and additional costs
implied by such delays.
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11
11. Environmental Impact
The net environmental impact associated with each alternative
emission control system should be determined. Both beneficial impacts
(e.g., reduced emissions attributed to a control system) and adverse
impacts (e.g., exacerbation of another pollution problem through use of
a control system) should be discussed and quantified. As pointed out
above, indirect environmental impacts (such as pollution impacts at an
off-site plant which manufacturers chemicals for use in pollution control
equipment) normally need not be considered. The analysis should be
presented in the form of the incremental impact of alternative control
systems relative to the system proposed as BACT in the permit application.
Some specific considerations are presented below.
A. Air Pollution Impact
The impact of air pollutants emitted from a gas stream or a
fugitive emission source can be assessed terms of either quanity of
emissions, modeled effects on air quality, or both. If application of a
control system directly removes or releases other air pollutants (or
precursors to other air pollutants), then the pollutants affected and
the impact of these emission changes should be identified. The analysis
can consider any pollutant affecting local air quality including pollutants
which are not currently regulated under the Act, but which may be of
special concern locally.
In the absence of a more systematic technique (e.g., market-type
systems, etc.) for allocating PSD increments, BACT determinations are
important for executing such allocations. PSD programs which depend on BACT
determinations to implement the allocation of increments should project
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12
desired levels of growth in an area so that 8ACT determinations for
each source will serve to insure that the total air impacts of future
growth are no greater than the available increments. Since in the first
years of the PSD program many areas may have neither a functioning market
system for allocating increments no accurate projects of desired growth,
it is important that such areas use the BACT determinations during this
initial period to conserve the remaining increments as much as possible
until more systematic allocation mechanisms are put in place.
B. Water Impact
Relative quantities of water used and water pollutants produced
and discharged as a result of use of each alternative emission control
system should be identified. Where possible, the analysis should assess
their effect on such local surface water quality parameters as pH,
turbidity, dissolved oxygen, salinity, toxic chemical levels and any
other important considerations, as well as on groundwater. The analysis
should consider whether applicable water quality standards are met and
the availability and effectiveness of various techniques to reduce
potential adverse effects.
C. Solid Waste Disposal Impact
The quality and quantity of solid waste (e.g., sludges, solids) that
must be stored and disposed of or recycled as the result of the applica-
tion of each alternative emission control system should be compared
with the quality and quantity of wastes created if the emission control
system proposed as BACT is used. The composition and various other
characteristics of the solid waste (such as permeability, water retention,
rewatering of dried material, compression strength, leachability of
dissolved ions, bulk density, ability to support vegetation growth and
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hazardous characteristics) which are significant with regard to potential
surface water pollution or transport into and contamination of sub-
surface waters or aquifers should be considered. The relative effec-
tiveness, hazard and opportunity for solid waste management options,
such as sanitary landfill, incineration, ana recycling, should be
identified and discussed.
0. Irreversible or Irretrievable Commitment of Resources
The BACT decision may consider the extent to which the alternative
emission control systems may involve a trade-off between short-term
environmental gains at the expense of long-term environmental losses
and the extent to which the alternative systems may result in irrever-
sible or irretrievable commitment of resources (for example, use of
scarce water resources).
E. Other Environmental Impacts
Incremental differences in noise levels, radiant heat, or dis-
sipated static electrical energy should be considered where appropriate.
Ill. Economic Impact
This analysis should address the economic impacts associated with
the incremental costs of installing and operating alternative control
systems above the economic impact associated with the system proposed
as BACT. The review should include a complete explanation of pro-
cedures for assessing economic impacts and any supporting data. As
outlined below, economic considerations can address direct economic
impacts on the firm and impacts on local economic growth.
A. Direct Economic Impacts on the Plant
Direct economic impacts on the plant should be examined through
evaluation of the following:
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1. Direct Costs
The direct cost for each control alternative should be presented
both on an incremental and on an overall basis. Investment costs,
operations and maintenance costs and annualized costs should be presented
separately. Annualized costs are operations and maintenance costs plus
depreciation and interest charges on the investment. Costs should be
itemized and explained. Credit for tax incentives should be included
along with credits for product recovery costs and by-product sales
generated from the use of control systems. The lifetime of the invest-
ment should be stated. Where possible, costs should be broken down
into process change costs (costs of less polluting production process)
and direct pollution abatement costs (cost of pollution control equipment).
The costs of air treatment, water treatment and solid waste disposal
should be presented separately. The analysis should also include the
total investment cost of the new facility.
As a guide in determining when control costs become excessive,
alternative control systems can be compared in terms of certain cost
effectiveness ratios. Such ratios may include the following:
° ratio of total control costs to total investment costs.
° cost per unit of pollution removed (for example, dollars/ton).
0 cost versus additional portion of remaining PSD increment
preserved for future growth.
° unit production costs (for example, mill/kw-hr, dollars/ton
of steel).
In some cases, the unit of production output may be difficult to determine,
as in the case of a plant producing many different products. In such
cases, unit production costs can be expressed as cost per dollar of
total sales.
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15
2. Capital Availability
Capital availability addresses the difficulty that some sources
may face in financing alternative control systems. Proof of such
claims should be fully documented.
B. Local Economic Impacts
Local economic impacts address the economic feasibility of al-
ternative BACT requirements and the impact of the production decisions
of the firm in response to alternative levels of control. For example,
a BACT alternative may alter the economics of a project to the point
where the decision would be made to cancel the construction or expan-
sion of a facility, to relocate a plant, to reduce the scale of opera-
tion, or to change the production mix. The local economic impacts of
such decisions should be assessed in terms of local employment effects
including number of jobs, dollars paid in salaries, and changes in
employee skill levels required. The guideline does not imply that the
BACT decision should force new projects to the brink of cancellation.
The BACT decision must be based on sound judgment, balancing environment
benefits with energy, economic, and other impacts.
Local economic impacts also can address the effect of various BACT
alternatives on air quality increment consumption and the subsequent
impact on future growth potential in the surrounding area. The BACT
decision should reflect policy decisions to conserve the available air
quality increment for future growth.
IV. Other Costs
Other costs associated with alternative emission control systems
may be considered where appropriate.
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ASSISTANCE IN DETERMINING BACT
Assistance to the states and Regional Offices in evaluating control
technology will continue to be provided through the OAQPS new source
review clearinghouse (August 1, 1977 memo, Walter C. Barber to Regional
Offices, "OAQPS Assistance for BACT/RACT/LAER Determinations"). Through
its repository of information on past BACT/RACT/LAER decisions, the
clearinghouse provides a communication link for advising reviewing
authorities of each other's determinations, thereby promoting consistency
in BACT determinations. The degree to which the clearinghouse will be
effective as a consistency-improving tool will depend on the degree to
which the BACT determinations are reported to OAQPS. All Regional Offices
are requested to submit BACT findings to the clearinghouse. In addition
to the repository, the clearinghouse system also provides a focal point
for answering questions related to policy issues and control technology.
With respect to control technology, OAQPS can assist in establishing the
range of alternative controls for a particular process, but cannot
evaluate case-by-case energy, environmental, and economic impacts or
select BACT emission levels. In short, the clearinghouse can be an
important input to the reviewing authority's decision, but it cannot
substitute for the case-by-case analysis required to select the appropriate
control technology.
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-2-
If you have any questions on this document Dlease refer them to
Norman Huey or David Joseph of the Air Programs 3ranch, Air and Hazard-
ous Materials Division, at (303) 837-3763.
Attachment
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• £PflReR\on.V\.H.U8RMtt
m, Colorado , ^
ompi 1 ation of Past Practices and Interpretations by EPA Region VIU-^ ooU'
¦4 on Air Quality Mining
908R80027
I. Background
h
On December 5, 1974, EPA promulgated regulations under the 1970
version of the Clean Air Act for the prevention of significant deter-
ioration of air quality (PSD). These regulations established a pro-
gram for protecting areas with air quality cleaner than the national
ambient air quality standards (NAAQS). The primary mechanism for
implementation of that program was a preconstruction review program
applicable to specific categories of major stationary sources. Nine-
teen source categories were listed in those regulations. Under that
new source review program which has been implemented by EPA, a pro-
posed major facility was reviewed according to the following criteria:
(1) The combined impacts of that source and other new sources in
the area could not exceed prescribed ambient air quality
increments. Increments for total suspended particulates
(TSP) and sulfur dioxide were established and in a given area
are a function of the PSD classification of the area; and
(2) The new or modified source must utilize best available con-
trol technology (BACT).
On August 7, 1977, Congress amended the Clean Air Act and Part C
of the new Act contains specific requirements for the prevention of
significant deterioration.
For the most part the 1977 Amendments were a codification of the
EPA regulations. However, some additional requirements were inclu-
ded. A few of these additional requirements are:
(1) The source category list was expanded to 29 and the Amend-
ments added a general provision requiring applicability to
any new or modified source which will have potential emis-
sions of 250 tons per year;
(2) The air quality increments were revised;
(3) Certain areas were established as mandatory Class I areas and
the Federal Land Managers for these areas were given specific
responsibilities to protect the air quality related values of
the areas; and
(4)
One calendar year of ambient air quality monitoring data may
be required to accompany a PSD application.
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