[Code of Federal Regulations]
[Title 40, Volume 2]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR51.100]
[Page 138-143]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS--Table of Contents
Subpart F--Procedural Requirements
Sec. 51.100 Definitions.
Authority: 42 U.S.C. 7401, 7411, 7412, 7413, 7414, 7470-7479, 7501-
7508, 7601, and 7602.
As used in this part, all terms not defined herein will have the
meaning given them in the Act:
(a) Act means the Clean Air Act (42 U.S.C. 7401 et seq., as amended
by Pub. L. 91-604, 84 Stat. 1676 Pub. L. 95-95, 91 Stat., 685 and Pub.
L. 95-190, 91 Stat., 1399.)
(b) Administrator means the Administrator of the Environmental
Protection Agency (EPA) or an authorized representative.
(c) Primary standard means a national primary ambient air quality
standard promulgated pursuant to section 109 of the Act.
(d) Secondary standard means a national secondary ambient air
quality standard promulgated pursuant to section 109 of the Act.
(e) National standard means either a primary or secondary standard.
(f) Owner or operator means any person who owns, leases, operates,
controls, or supervises a facility, building, structure, or installation
which directly or indirectly result or may result in emissions of any
air pollutant for which a national standard is in effect.
(g) Local agency means any local government agency other than the
State agency, which is charged with responsibility for carrying out a
portion of the plan.
(h) Regional Office means one of the ten (10) EPA Regional Offices.
(i) State agency means the air pollution control agency primarily
responsible for development and implementation of a plan under the Act.
(j) Plan means an implementation plan approved or promulgated under
section 110 of 172 of the Act.
(k) Point source means the following:
(1) For particulate matter, sulfur oxides, carbon monoxide, volatile
organic compounds (VOC) and nitrogen dioxide--
(i) Any stationary source the actual emissions of which are in
excess of 90.7 metric tons (100 tons) per year of the pollutant in a
region containing an area whose 1980 urban place population, as defined
by the U.S. Bureau of the Census, was equal to or greater than 1
million.
(ii) Any stationary source the actual emissions of which are in
excess of 22.7 metric tons (25 tons) per year of the pollutant in a
region containing an area whose 1980 urban place population, as defined
by the U.S. Bureau of the Census, was less than 1 million; or
(2) For lead or lead compounds measured as elemental lead, any
stationary source that actually emits a total of 4.5 metric tons (5
tons) per year or more.
(l) Area source means any small residential, governmental,
institutional, commercial, or industrial fuel combustion operations;
onsite solid waste disposal facility; motor vehicles, aircraft vessels,
or other transportation facilities or other miscellaneous sources
identified through inventory techniques similar to those described in
the ``AEROS Manual series, Vol. II AEROS User's Manual,'' EPA-450/2-76-
029 December 1976.
(m) Region means an area designated as an air quality control region
(AQCR) under section 107(c) of the Act.
(n) Control strategy means a combination of measures designated to
achieve the aggregate reduction of emissions necessary for attainment
and maintenance of national standards including, but not limited to,
measures such as:
(1) Emission limitations.
[[Page 139]]
(2) Federal or State emission charges or taxes or other economic
incentives or disincentives.
(3) Closing or relocation of residential, commercial, or industrial
facilities.
(4) Changes in schedules or methods of operation of commercial or
industrial facilities or transportation systems, including, but not
limited to, short-term changes made in accordance with standby plans.
(5) Periodic inspection and testing of motor vehicle emission
control systems, at such time as the Administrator determines that such
programs are feasible and practicable.
(6) Emission control measures applicable to in-use motor vehicles,
including, but not limited to, measures such as mandatory maintenance,
installation of emission control devices, and conversion to gaseous
fuels.
(7) Any transportation control measure including those
transportation measures listed in section 108(f) of the Clean Air Act as
amended.
(8) Any variation of, or alternative to any measure delineated
herein.
(9) Control or prohibition of a fuel or fuel additive used in motor
vehicles, if such control or prohibition is necessary to achieve a
national primary or secondary air quality standard and is approved by
the Administrator under section 211(c)(4)(C) of the Act.
(o) Reasonably available control technology (RACT) means devices,
systems, process modifications, or other apparatus or techniques that
are reasonably available taking into account:
(1) The necessity of imposing such controls in order to attain and
maintain a national ambient air quality standard;
(2) The social, environmental, and economic impact of such controls;
and
(3) Alternative means of providing for attainment and maintenance of
such standard. (This provision defines RACT for the purposes of
Sec. 51.341(b) only.)
(p) Compliance schedule means the date or dates by which a source or
category of sources is required to comply with specific emission
limitations contained in an implementation plan and with any increments
of progress toward such compliance.
(q) Increments of progress means steps toward compliance which will
be taken by a specific source, including:
(1) Date of submittal of the source's final control plan to the
appropriate air pollution control agency;
(2) Date by which contracts for emission control systems or process
modifications will be awarded; or date by which orders will be issued
for the purchase of component parts to accomplish emission control or
process modification;
(3) Date of initiation of on-site construction or installation of
emission control equipment or process change;
(4) Date by which on-site construction or installation of emission
control equipment or process modification is to be completed; and
(5) Date by which final compliance is to be achieved.
(r) Transportation control measure means any measure that is
directed toward reducing emissions of air pollutants from transportation
sources. Such measures include, but are not limited to, those listed in
section 108(f) of the Clean Air Act.
(s) Volatile organic compounds (VOC) means any compound of carbon,
excluding carbon monoxide, carbon dioxide, carbonic acid, metallic
carbides or carbonates, and ammonium carbonate, which participates in
atmospheric photochemical reactions.
(1) This includes any such organic compound other than the
following, which have been determined to have negligible photochemical
reactivity: methane; ethane; methylene chloride (dichloromethane);
1,1,1-trichloroethane (methyl chloroform); 1,1,2-trichloro-1,2,2-
trifluoroethane (CFC-113); trichlorofluoromethane (CFC-11);
dichlorodifluoromethane (CFC-12); chlorodifluoromethane (HCFC-22);
trifluoromethane (HFC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-
114); chloropentafluoroethane (CFC-115); 1,1,1-trifluoro 2,2-
dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-
dichloro 1-fluoroethane (HCFC-141b); 1-chloro 1,1-difluoroethane (HCFC-
142b); 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124); pentafluoroethane
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1-trifluoroethane
(HFC-143a); 1,1-
[[Page 140]]
difluoroethane (HFC-152a); parachlorobenzotrifluoride (PCBTF); cyclic,
branched, or linear completely methylated siloxanes; acetone;
perchloroethylene (tetrachloroethylene); 3,3-dichloro-1,1,1,2,2-
pentafluoropropane (HCFC-225ca); 1,3-dichloro-1,1,2,2,3-
pentafluoropropane (HCFC-225cb); 1,1,1,2,3,4,4,5,5,5-decafluoropentane
(HFC 43-10mee); difluoromethane (HFC-32); ethylfluoride (HFC-161);
1,1,1,3,3,3-hexafluoropropane (HFC-236fa); 1,1,2,2,3-pentafluoropropane
(HFC-245ca); 1,1,2,3,3-pentafluoropropane (HFC-245ea); 1,1,1,2,3-
pentafluoropropane (HFC-245eb); 1,1,1,3,3-pentafluoropropane (HFC-
245fa); 1,1,1,2,3,3-hexafluoropropane (HFC-236ea); 1,1,1,3,3-
pentafluorobutane (HFC-365mfc); chlorofluoromethane (HCFC-31); 1 chloro-
1-fluoroethane (HCFC-151a); 1,2-dichloro-1,1,2-trifluoroethane (HCFC-
123a); 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxy-butane
(C4F9OCH3); 2-(difluoromethoxymethyl)-
1,1,1,2,3,3,3-heptafluoropropane
((CF3)2CFCF2OCH3); 1-ethoxy-
1,1,2,2,3,3,4,4,4-nonafluorobutane
(C4F9OC2H5); 2-
(ethoxydifluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane
((CF3)2CFCF2OC2H5)
; methyl acetate and perfluorocarbon compounds which fall into these
classes:
(i) Cyclic, branched, or linear, completely fluorinated alkanes;
(ii) Cyclic, branched, or linear, completely fluorinated ethers with
no unsaturations;
(iii) Cyclic, branched, or linear, completely fluorinated tertiary
amines with no unsaturations; and
(iv) Sulfur containing perfluorocarbons with no unsaturations and
with sulfur bonds only to carbon and fluorine.
(2) For purposes of determining compliance with emissions limits,
VOC will be measured by the test methods in the approved State
implementation plan (SIP) or 40 CFR part 60, appendix A, as applicable.
Where such a method also measures compounds with negligible
photochemical reactivity, these negligibility-reactive compounds may be
excluded as VOC if the amount of such compounds is accurately
quantified, and such exclusion is approved by the enforcement authority.
(3) As a precondition to excluding these compounds as VOC or at any
time thereafter, the enforcement authority may require an owner or
operator to provide monitoring or testing methods and results
demonstrating, to the satisfaction of the enforcement authority, the
amount of negligibly-reactive compounds in the source's emissions.
(4) For purposes of Federal enforcement for a specific source, the
EPA shall use the test methods specified in the applicable EPA-approved
SIP, in a permit issued pursuant to a program approved or promulgated
under title V of the Act, or under 40 CFR part 51, subpart I or appendix
S, or under 40 CFR parts 52 or 60. The EPA shall not be bound by any
State determination as to appropriate methods for testing or monitoring
negligibly-reactive compounds if such determination is not reflected in
any of the above provisions.
(t)-(w) [Reserved]
(x) Time period means any period of time designated by hour, month,
season, calendar year, averaging time, or other suitable
characteristics, for which ambient air quality is estimated.
(y) Variance means the temporary deferral of a final compliance date
for an individual source subject to an approved regulation, or a
temporary change to an approved regulation as it applies to an
individual source.
(z) Emission limitation and emission standard mean a requirement
established by a State, local government, or the Administrator which
limits the quantity, rate, or concentration of emissions of air
pollutants on a continuous basis, including any requirements which limit
the level of opacity, prescribe equipment, set fuel specifications, or
prescribe operation or maintenance procedures for a source to assure
continuous emission reduction.
(aa) Capacity factor means the ratio of the average load on a
machine or equipment for the period of time considered to the capacity
rating of the machine or equipment.
(bb) Excess emissions means emissions of an air pollutant in excess
of an emission standard.
[[Page 141]]
(cc) Nitric acid plant means any facility producing nitric acid 30
to 70 percent in strength by either the pressure or atmospheric pressure
process.
(dd) Sulfuric acid plant means any facility producing sulfuric acid
by the contact process by burning elemental sulfur, alkylation acid,
hydrogen sulfide, or acid sludge, but does not include facilities where
conversion to sulfuric acid is utilized primarily as a means of
preventing emissions to the atmosphere of sulfur dioxide or other sulfur
compounds.
(ee) Fossil fuel-fired steam generator means a furnance or bioler
used in the process of burning fossil fuel for the primary purpose of
producing steam by heat transfer.
(ff) Stack means any point in a source designed to emit solids,
liquids, or gases into the air, including a pipe or duct but not
including flares.
(gg) A stack in existence means that the owner or operator had (1)
begun, or caused to begin, a continuous program of physical on-site
construction of the stack or (2) entered into binding agreements or
contractual obligations, which could not be cancelled or modified
without substantial loss to the owner or operator, to undertake a
program of construction of the stack to be completed within a reasonable
time.
(hh)(1) Dispersion technique means any technique which attempts to
affect the concentration of a pollutant in the ambient air by:
(i) Using that portion of a stack which exceeds good engineering
practice stack height:
(ii) Varying the rate of emission of a pollutant according to
atmospheric conditions or ambient concentrations of that pollutant; or
(iii) Increasing final exhaust gas plume rise by manipulating source
process parameters, exhaust gas parameters, stack parameters, or
combining exhaust gases from several existing stacks into one stack; or
other selective handling of exhaust gas streams so as to increase the
exhaust gas plume rise.
(2) The preceding sentence does not include:
(i) The reheating of a gas stream, following use of a pollution
control system, for the purpose of returning the gas to the temperature
at which it was originally discharged from the facility generating the
gas stream;
(ii) The merging of exhaust gas streams where:
(A) The source owner or operator demonstrates that the facility was
originally designed and constructed with such merged gas streams;
(B) After July 8, 1985 such merging is part of a change in operation
at the facility that includes the installation of pollution controls and
is accompanied by a net reduction in the allowable emissions of a
pollutant. This exclusion from the definition of dispersion techniques
shall apply only to the emission limitation for the pollutant affected
by such change in operation; or
(C) Before July 8, 1985, such merging was part of a change in
operation at the facility that included the installation of emissions
control equipment or was carried out for sound economic or engineering
reasons. Where there was an increase in the emission limitation or, in
the event that no emission limitation was in existence prior to the
merging, an increase in the quantity of pollutants actually emitted
prior to the merging, the reviewing agency shall presume that merging
was significantly motivated by an intent to gain emissions credit for
greater dispersion. Absent a demonstration by the source owner or
operator that merging was not significantly motivated by such intent,
the reviewing agency shall deny credit for the effects of such merging
in calculating the allowable emissions for the source;
(iii) Smoke management in agricultural or silvicultural prescribed
burning programs;
(iv) Episodic restrictions on residential woodburning and open
burning; or
(v) Techniques under Sec. 51.100(hh)(1)(iii) which increase final
exhaust gas plume rise where the resulting allowable emissions of sulfur
dioxide from the facility do not exceed 5,000 tons per year.
(ii) Good engineering practice (GEP) stack height means the greater
of:
(1) 65 meters, measured from the ground-level elevation at the base
of the stack:
(2)(i) For stacks in existence on January 12, 1979, and for which
the owner
[[Page 142]]
or operator had obtained all applicable permits or approvals required
under 40 CFR parts 51 and 52.
Hg = 2.5H,
provided the owner or operator produces evidence that this equation was
actually relied on in establishing an emission limitation:
(ii) For all other stacks,
Hg = H + 1.5L
where:
Hg = good engineering practice stack height, measured from
the ground-level elevation at the base of the stack,
H = height of nearby structure(s) measured from the ground-level
elevation at the base of the stack.
L = lesser dimension, height or projected width, of nearby structure(s)
provided that the EPA, State or local control agency may require the use
of a field study or fluid model to verify GEP stack height for the
source; or
(3) The height demonstrated by a fluid model or a field study
approved by the EPA State or local control agency, which ensures that
the emissions from a stack do not result in excessive concentrations of
any air pollutant as a result of atmospheric downwash, wakes, or eddy
effects created by the source itself, nearby structures or nearby
terrain features.
(jj) Nearby as used in Sec. 51.100(ii) of this part is defined for a
specific structure or terrain feature and
(1) For purposes of applying the formulae provided in
Sec. 51.100(ii)(2) means that distance up to five times the lesser of
the height or the width dimension of a structure, but not greater than
0.8 km (\1/2\ mile), and
(2) For conducting demonstrations under Sec. 51.100(ii)(3) means not
greater than 0.8 km (\1/2\ mile), except that the portion of a terrain
feature may be considered to be nearby which falls within a distance of
up to 10 times the maximum height (Ht) of the feature, not to
exceed 2 miles if such feature achieves a height (Ht) 0.8 km
from the stack that is at least 40 percent of the GEP stack height
determined by the formulae provided in Sec. 51.100(ii)(2)(ii) of this
part or 26 meters, whichever is greater, as measured from the ground-
level elevation at the base of the stack. The height of the structure or
terrain feature is measured from the ground-level elevation at the base
of the stack.
(kk) Excessive concentration is defined for the purpose of
determining good engineering practice stack height under
Sec. 51.100(ii)(3) and means:
(1) For sources seeking credit for stack height exceeding that
established under Sec. 51.100(ii)(2) a maximum ground-level
concentration due to emissions from a stack due in whole or part to
downwash, wakes, and eddy effects produced by nearby structures or
nearby terrain features which individually is at least 40 percent in
excess of the maximum concentration experienced in the absence of such
downwash, wakes, or eddy effects and which contributes to a total
concentration due to emissions from all sources that is greater than an
ambient air quality standard. For sources subject to the prevention of
significant deterioration program (40 CFR 51.166 and 52.21), an
excessive concentration alternatively means a maximum ground-level
concentration due to emissions from a stack due in whole or part to
downwash, wakes, or eddy effects produced by nearby structures or nearby
terrain features which individually is at least 40 percent in excess of
the maximum concentration experienced in the absence of such downwash,
wakes, or eddy effects and greater than a prevention of significant
deterioration increment. The allowable emission rate to be used in
making demonstrations under this part shall be prescribed by the new
source performance standard that is applicable to the source category
unless the owner or operator demonstrates that this emission rate is
infeasible. Where such demonstrations are approved by the authority
administering the State implementation plan, an alternative emission
rate shall be established in consultation with the source owner or
operator.
(2) For sources seeking credit after October 11, 1983, for increases
in existing stack heights up to the heights established under
Sec. 51.100(ii)(2), either (i) a maximum ground-level concentration due
in whole or part to downwash, wakes or eddy effects as provided in
[[Page 143]]
paragraph (kk)(1) of this section, except that the emission rate
specified by any applicable State implementation plan (or, in the
absence of such a limit, the actual emission rate) shall be used, or
(ii) the actual presence of a local nuisance caused by the existing
stack, as determined by the authority administering the State
implementation plan; and
(3) For sources seeking credit after January 12, 1979 for a stack
height determined under Sec. 51.100(ii)(2) where the authority
administering the State implementation plan requires the use of a field
study or fluid model to verify GEP stack height, for sources seeking
stack height credit after November 9, 1984 based on the aerodynamic
influence of cooling towers, and for sources seeking stack height credit
after December 31, 1970 based on the aerodynamic influence of structures
not adequately represented by the equations in Sec. 51.100(ii)(2), a
maximum ground-level concentration due in whole or part to downwash,
wakes or eddy effects that is at least 40 percent in excess of the
maximum concentration experienced in the absence of such downwash,
wakes, or eddy effects.
(ll)-(mm) [Reserved]
(nn) Intermittent control system (ICS) means a dispersion technique
which varies the rate at which pollutants are emitted to the atmosphere
according to meteorological conditions and/or ambient concentrations of
the pollutant, in order to prevent ground-level concentrations in excess
of applicable ambient air quality standards. Such a dispersion technique
is an ICS whether used alone, used with other dispersion techniques, or
used as a supplement to continuous emission controls (i.e., used as a
supplemental control system).
(oo) Particulate matter means any airborne finely divided solid or
liquid material with an aerodynamic diameter smaller than 100
micrometers.
(pp) Particulate matter emissions means all finely divided solid or
liquid material, other than uncombined water, emitted to the ambient air
as measured by applicable reference methods, or an equivalent or
alternative method, specified in this chapter, or by a test method
specified in an approved State implementation plan.
(qq) PM10 means particulate matter with an aerodynamic
diameter less than or equal to a nominal 10 micrometers as measured by a
reference method based on appendix J of part 50 of this chapter and
designated in accordance with part 53 of this chapter or by an
equivalent method designated in accordance with part 53 of this chapter.
(rr) PM10 emissions means finely divided solid or liquid
material, with an aerodynamic diameter less than or equal to a nominal
10 micrometers emitted to the ambient air as measured by an applicable
reference method, or an equivalent or alternative method, specified in
this chapter or by a test method specified in an approved State
implementation plan.
(ss) Total suspended particulate means particulate matter as
measured by the method described in appendix B of part 50 of this
chapter.
[51 FR 40661, Nov. 7, 1986, as amended at 52 FR 24712, July 1, 1987; 57
FR 3945, Feb. 3, 1992; 61 FR 4590, Feb. 7, 1996; 61 FR 16060, Apr. 11,
1996; 61 FR 30162, June 14, 1996; 61 FR 52850, Oct. 8, 1996; 62 FR
44903, Aug. 25, 1997; 63 FR 9151, Feb. 24, 1998; 63 FR 17333, Apr. 9,
1998]