Air Program Strategy for Attainment
and Maintenance of Ambient Air Quality
Standards and Control of Other Pollutants
U. S. Environmental Protection Agency
Washington, D. C. 20460
1977
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TABLE OF CONTENTS
Preface i
I. Introduction 1
A. Overview 1
B. Legislative Philosophy and Objectives 10
1. Overview of Legislative Authorities 10
2. Legislative Objectives 11
3. State Implementation Plans 13
C. Overview of Status of Implementation of the Act's
Requirements and Future Actions 15
D. Issues Related to the National Ambient Air
Quality Standards 18
1. Overview 18
2. Total Suspended Particulates 22
3. Sulfur Dioxide and Sulfates 26
4. Photochemical Oxidants 27
5. Nitrogen Dioxide 33
E. Monitoring Air Pollution. . .- 33
II. Status of Air Pollution Control and Future Actions 37
A. Overview of Progress to Date 37
B. SIP Revisions 40
C. Emission Reductions from Sources—Issues and Policy ... 42
1. Introduction 42
2. Total Suspended Particulates and Sulfur Dioxide ... 43
a. Primary Non-Ferrous Metals Smelters 45
b. Iron and Steel Mills/Coke Plants 47
c. Coal-Fired Power Plants 48
d. Tall Stacks and Supplemental Control Systems. . . 49
e. EPA's Policy on SIP Revisions Aimed at
Permitting Use of Higher Sulfur Fuels 51
3. Photochemical Oxidants, Carbon Monoxide, and
Nitrogen Dioxide 54
a. Introduction 54
b. Motor Vehicle Emissions Control 56
c. Motor Vehicle Emissions Inspection
and Maintenance 62
d. Control of Stationary Sources 64
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TABLE OF CONTENTS - (CONT'D)
D. Attainment/Maintenance of Standards in Problem
Areas and New Sources Control 67
1. Introduction 67
2. Development of a Comprehensive Planning
and Decision-Making Process 69
3. EPA's Formal Planning Requirements 73
4. New Stationary Sources Review and Control 75
a. Introduction 75
b. New Sources in Nonattainment Areas--
"Emissions Offset" Policy 77
c. Prevention of Significant Deterioration
of Air Quality 78
d. Federal New Source Performance Standards
(NSPS) for Criteria Pollutants 32
III. The Control of Other Than Criteria Pollutants 85
A. Introduction 85
B. National Emission Standards for Hazardous
Air Pollutants 87
C. Control of Selected Pollutants 90
D. Lead 90
E. Arsenic 91
F. High Volume Industrial Organic Chemicals (HVIOC) 92
R. Polycyclic Organic Matter 95
H. Polychlorinated Biphenyls (PCBs) 96
I. Cadmium 97
J. Manganese 97
K. Other Trace Metals 97
L. Odors 98
Table I
Summary of NESHAP 89
Table II
High Volume Industrial Organic Chemicals Being
Assessed for Air Pollution Potential 94
Appendix A
1. National Ambient Air Quality Standards A-l
2. Sources of Information on Health Effects
of Air Pollutants A-2
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TABLE OF CONTENTS - (CONT'D)
Appendix B
Summary of New Source Performance Standards B-l
Appendix C
Determination of Best Available Control Technology
and Reasonably Available Control Technology C-l
A. Best Available Control Technology C-l
B. Reasonably Available Control Technology C-2
1. General C-2
2. Specific Application of the RACT Concept. . . . C-4
a. As an Aid in Defining BACT C-4
b. RACT coupled with Tall Stacks and/or SCS. . C-5
C. Reasonably Available Control Measures for
' CO and Ox C-8
Appendix D
Summary of States Issued Calls for SIP Revisions
July 1, 1976, and Pollutants for Which Plan
Revisions Are Required D-l
Aopendix E
List of Abbreviations, Symbols, and Acronymns E-l
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Preface
This Air Program Strategy for Attainment and Maintenance of Ambient
Air Quality Standards states EPA's strategy for implementation of the
Clean Air Act's requirements for compliance with ambient air quality
standards, to be achieved principally through adherence to air quality-
based emission limitations. This strategy also applies to the control
of pollutants less pervasive than those covered by air quality standards.
These less pervasive pollutants are generally subject to direct emission-
oriented controls.
The discussion which follows is a statement of the Agency's objectives
and plans for future air pollution control efforts, based on the require-
ments and philosophy of the Clean Air Act and on the national status of
air pollution control. This document should be considered both as a
status report and as an outline of directions for the future.
The discussion is not intended as a complete statement of the
Environmental Protection Agency's air pollution control program; it is
related primarily to the operational objectives and programs of the
Agency and the requisite companion programs of the States in achieving
the Clean Air Act's goals. Thus, the discussion does not cover the
Agency's substantial effort to define health effects, welfare effects,
control technology for mobile and stationary sources, or the definition
of mechanisms for atmospheric transportation of pollutants, nor is it
an exhaustive compendium of all matters related to air pollution control.
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AIR PROGRAM STRATEGY FOR THE ATTAINMENT AND
MAINTENANCE OF AMBIENT AIR QUALITY STANDARDS
AND CONTROL OF OTHER POLLUTANTS
I. Introduction
A. Overview
The 1970 Amendments to the Clean Air Act have been considered a
landmark in the nation's efforts to control air pollution both in terms
of their comprehensiveness and in terms of their setting forth the
institutional framework for State and Federal action. Pursuant to that
Act, National Ambient Air Quality Standards were established for six
significant and widespread air pollutants, implementation plans for the
attainment and maintenance of these standards were developed by the
States, a program for the establishment of Federal emission standards
for significant new air pollution sources and for hazardous air pollu-
tants was initiated, and statutorily specified limitations on emissions
from light duty motor vehicles were imposed.
The Clean Air Act's fundamental goal is the protection of public
health and welfare from the effects of air pollution. This goal is to be
attained through: the restoration of unhealthy air (and its preservation,
once restored) to at least acceptable status through State controls on
stationary sources and transportation systems and Federal controls on
new motor vehicles; clean air is to be preserved from unnecessary and
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significant degradation; future increases in emissions are to be
minimized in an equitable manner (that does not put particular regions
of the country at a competitive disadvantage or advantage) through
Federal new source emissions limits based on best technology (considering
cost); and national emission limits are to be set for the strict control
of hazardous localized pollution problems. In achieving these goals,
the Act recognizes the high priority need for State control actions.
The Act, in general, envisions the development and implementation
of air pollution controls as a State responsibility, with the Federal
government setting minimally acceptable criteria for assuring that
public health and welfare are adequately protected. For all cases in
which the Federal government has not set standards, the States are free
to impose whatever controls they see fit. For cases in which the
Federal government has set controls, the States may establish a more
stringent requirement but may not set a more lenient requirement. The
Act largely reserves to the Federal government the control of new motor
vehicles, and also places on it primary responsibility for the control
of hazardous pollutants and the setting of emissions standards for new
significant stationary sources. In the case of both hazardous emissions
standards and new stationary sources controls the States may request the
delegation of enforcement responsibilities. Given the policy of State
primacy in the Act, it has been EPA policy to defer to the States and to
take action (generally after extensive consultation with States) only in
cases of State failure to act or in cases where Federal action is
directly indicated.
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The past six years have served as a major testing ground for both
the fundamental goals of the Act and the institutional arrangements
contemplated for their achievement.
Six years after the passage of the Act, violations of the National
Ambient Air Quality Standards for one or more pollutants still exist in
at least 160 of the 247 air quality control regions. These standards
were to have been attained in the 1973-1975 time frame. Yet substantial
progress has been made:
. The estimated number of people exposed to total suspended
particulates in excess of the annual primary standard decreased
from 73 million in 1970 to less than 50 million in 1975, i.e.,
the exposed population has been reduced by more than one-third
since the passage of the Clean Air Act.
. The concentrations of sulfur dioxide in urban areas have
decreased by an average of 30 percent since 1970. Only a few
monitors in a small number of urban areas report violations of
standards.
. At monitoring sites where data exist covering three or more
years, some 80 percent show improvement in measured levels of
carbon monoxide.
Outside of California, monitoring data for oxidants and nitrogen
dioxide are inadequate to characterize trends since the passage of the
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Clean Air Act. With more stringent automobile standards, some improvement
in oxidant levels would be expected. However, widespread violations of
one-hour ambient air quality standards are reported and the problem of
hydrocarbon emission remains as one of the more pressing priorities in
air pollution control. With respect to nitrogen dioxide, the reverse is
true. Only limited controls over stationary source emissions have been
imposed and no Federal limits for emissions from new motor vehicles
existed prior to the 1973 model year. With increased energy consumption,
the trends in ambient levels of nitrogen dioxide would be expected to be
up. However, in contrast to oxidants, very few areas have violations of
the ambient air quality standards. Control considerations with respect
to nitrogen dioxide are, in general, ones more of prevention of future
pollution problems than of remedial action directed at current levels.
Other air pollutants that have been of traditional concern, such as
polycyclic organic matter (POM), show decreasing trends in ambient air
concentrations. These trends are generally due to the imposition of
controls under the State Implementation Plans for other pollutants
(e.g., general particulate control leads to reductions in the emissions
of many of the specific substances that may be of concern), to the shift
in the use of certain fuels (e.g., the reduction in POM is due to the
decreasing use of coal as a fuel for home and commercial heating), or to
the imposition of specific controls for the pollutants in question
(e.g., control of the lead content of gasoline). Additional, newer
evidence indicates that certain substances not heretofore considered
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significant air pollutants may represent an increasing threat to public
health. An example of these substances is sulfates (which may account
for, at least partially, the health effects associated with sulfur
dioxide and/or particulates), whose concentrations have not been reduced
in keeping with the reductions achieved for sulfur dioxide. Other such
substances are the organic chemicals emitted by the chemical industry;
these substances are increasingly suspected of being toxic and/or
carcinogenic, yet emissions are increasing and the ambient concentrations
(as well as the effects) are not known. Other substances have only
recently been found to be of great concern in terms of environmental
impacts through the air. An example of these is polychlorinated biphenyls
(PCB), which may have to be controlled as an air pollutant due to the
contribution of air emissions to water pollution problems.
Air pollution control is predicated upon the development of regulations
covering emitting sources and the compliance with regulations by the
affected sources. More than 200,000 sources are subject to the limitations
prescribed in State Implementation Plans. Of these sources, some 22,000
are defined as major, i.e., capable of emitting more than 100 tons of
pollutants a year. As a class, these major sources produce about 85
percent of all air pollution from stationary sources. Consequently,
enforcement efforts (both State/local and Federal) have concentrated on
bringing these emitters into compliance with applicable regulations. As
a result, some 90 percent of these sources are either now in compliance
or on firm schedules leading to compliance.
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Although the Clean Air Act clearly sets forth the concept of
State primacy in enforcing State Implementation Plan-based air pollution
regulations, a major Federal effort has been required. Since 1972, the
Federal enforcement staff has increased by 640 percent. Over 10,000
investigations a year are being conducted by Federal enforcement personnel.
This situation has resulted from both the insufficiency of State/local
resources for enforcement related work (it is estimated that on a
nationwide basis State/local air pollution control agency staffing is
only about 70 percent of what is required to implement Clean Air Act
requirements) and the extremely difficult task of imposing control
requirements on certain inherently dirty industries (i.e., steel, primary
smelters, coal fired electric power generation) that are national in
scope. Also, the responsibility for enforcing Federal New Source
Performance and Hazardous Air Pollutant regulations continues to be with
the Federal government. Less than 15 States have been delegated responsi-
bility to carry out these provisions of the Clean Air Act.
Failure to achieve air quality standards in many areas despite
substantial reductions in emissions due to a major Federal program to
both promulgate and enforce air pollution regulations under State
Implementation Plans represents the six-year reality of the implementation of
the Clean Air Act. What happens next and what are the priorities of
EPA are the questions addressed and put into perspective in the strategy
document discussion. Essentially the strategy projects a continuation
into the future of the basic programs which have served to define the
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implementation of the Clean Air Act over the past six years, modified
where appropriate on the basis of the experience gained and new infor-
mation obtained during that time:
1. The primary objective is the attainment of ambient air quality
standards. On July 1, 1976 the Governors of 45 States were
notified that their implementation plans were inadequate to
attain standards and were requested to develop appropriate
revisions. These revisions are expected to involve the appli-
cation of reasonably available controls to all sources as
required to attain and maintain standards. Additionally, to
the extent that (even after the application of these restrictions)
an area still does not meet, or will not maintain, the air
quality standards, more long-range actions are required,
dealing with growth, polluting facility siting, and institutional
changes. Pollution emitting facilities are expected to come
into compliance with new regulations as soon as practicable,
but not more than three years after the effective date of the
regulation except in exceptional circumstances.
2. A major Federal role in meeting ambient air quality standards
will continue. Failures by the States in some cases to develop
the requisite regulatory framework for air pollution control
will continue to necessitate Federal action to fill the gaps
in otherwise adequate State control programs. Likewise, the
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extension of air pollution control to a large number of
sources not presently covered, or covered inadequately, will
intensify the need for enforcement action. EPA will seek to
supplement State/local resources to facilitate State assump-
tion of enforcement responsibilities,but, as necessary, it
will continue to undertake Federal enforcement action under
State implementation plan regulations.
3. EPA activities to identify and control pollutants other than
those covered by National Ambient Air Quality Standards are
likely to expand. The definition of the substances emitted
by the chemicals manufacturing industry in terms of the sources,
amounts, and potential health effects of the substances is
underway. It is expected that a number of these substances will
turn out to be of a toxic and/or carcinogenic nature, requiring
control as hazardous air pollutants. As a precautionary measure,
the setting of new source performance standards will be aimed
at minimizing increases in the emissions of these substances.
Additional studies of the emissions of various substances
(e.g., metals and other chemicals) from various sources are
likely to result in the identification of the need for the
development of control requirements, such as the control of
PCB's from incinerators and the control of arsenic from
smelters. Other work in the occupational health and
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environmental health fields can be expected to reveal the need
for protection of the public health from the effects of many
substances not heretofore identified as air pollutants.
To a large extent the hardest phase of the efforts to meet ambient
air quality standards is yet to come. The previously mentioned progress
has been achieved through the application of controls to sources generally
amenable to control requirements. The problems of the future may be of
such a magnitude and of such inherent difficulty that ambient air quality
standards may not be achieveable in some areas for many years or even
decades. However, new regulatory requirements, new approaches to
difficult problems, and continued attention to problems of sources
compliance (including the continuing compliance of mobile sources with
Federal new car emission standards) are all needed before it can be
concluded that all possible efforts have been made to meet the goals of
the Clean Air Act.
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B. Legislative Philosophy and Objectives
1. Overview of Legislative Authorities
In order to protect health and welfare, the Clean Air Act* establishes
several mechanisms to reduce and prevent air pollution while minimizing air
pollution control as either an impediment to interstate commerce or a
factor in interstate competition for new polluting facilities. As the
basic objectives to be achieved in the abatement of existing pollution,
the Clean Air Act calls for National Ambient Air Quality Standards (NAAQS).
The NAAQS set forth the allowable concentrations in ambient air for a set
of pollutants associated with diverse sources widely distributed throughout
the nation.** To attain and maintain the NAAQS, States (or EPA, if
necessary) must establish appropriate emission limits and other necessary
measures for specific facilities or activities. These emission limits
are set forth in a State Implementation Plan (SIP).
To prevent pollutant buildups (and to aid in maintaining as well as
attaining the NAAQS), the Clean Air Act provides several mechanisms
aimed particularly at new sources: New Source Performance Standards
(NSPS), emission standards for new vehicles, and prevention of significant
* References to the Clean Air Act (or simply the "Act") in this document
imply reference to all its amendments, notable among them being the
Energy Supply and Environmental Coordination Act (ESECA) of 1974
(PL 93-319), Clean Air Amendments of 1970 (PL 91-604), and the Air
Quality Act of 1967 (PL 90-148). The 1970 amendments specified the
mandatory time frames for attainment and maintenance of standards.
** Appendix A summarizes these standards.
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deterioration. Of course, the NAAQS-based and derived emission restrictions
(i.e., those set under SIPs) apply to new sources as well.
For the control of pollutants other than those for which NAAQS are
set, the Clean Air Act provides two basic alternatives. First, National
Emission Standards for Hazardous Air Pollutants (NESHAP) can be set to
abate less widespread new and existing sources of pollutants that are
very harmful even in limited, localized concentrations. Second, New
Source Performance Standards provisions of the Act also provide authority
for the control of new or modified sources of localized pollutants.
Except where NSPS relate to pollutants controlled by NAAQS or NESHAP,
establishment of NSPS trigger requirements for States to control
existing sources of specified pollutants pursuant to Federal guidelines.
In addition, authorities are available for the control of fuel additives
and aircraft emissions.
2. Legislative Objectives
The Act gives first priority to the protection of health, establishing
mandatory times for the attainment of standards protective of health.
For standards protective of welfare, the Act provides for limited administrative
discretion as to the time of attainment.* The setting of environmental
standards that are to be met nationally reflects the Congressional
decision to provide for an adequate level of health and welfare protection
* NAAQS set for the protection of public health are called primary
standards; those set for protecting welfare are called secondary
standards.
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(through Federal standards) while preserving State* prerogatives in
making specific control decisions (through the development and imple-
mentation of State air pollution control plans).
Several interrelated types of action make up the process by which
environmental standards are to be attained. The Act mandates the adoption
of legally enforceable emission reduction plans. It also provides for
emission limitations to be achieved on a nationwide basis. For example,
emission limits achievable by best adequately demonstrated technology
(considering cost) are to be set for new or modified stationary air
pollution sources and mandated emission reductions are set for new light
duty motor vehicles. The Act further requires the use of certain
controls not traditionally applied to air pollution control, such as
the control of land use and transportation when conventional emission
limits are inadequate to meet the environmental goals within the mandatory
time schedules set forth in the Act, or when States choose to use such
controls in lieu of more traditional control measures.
The philosophy circumscribing the State Implementation Plan process
is as follows:
. The Federal Government is to set environmental standards.
. The States are required to design and implement the plan for
achieving the environmental standards.
* The Act defines as States the 50 states, the District of Columbia,
Puerto Rico, Guam, American Samoa, and the Virgin Islands.
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. Opportunity must be provided for public participation in the
development of Federal standards, State plans, and subsequent
changes in such standards or plans. Furthermore, information
must be made available to the public on State progress in
carrying out the plan.
. The Federal Government is to take action when States do not
adopt or carry out an adequate plan for achieving .the standards.
3. State Implementation Plans
The setting of National Ambient Air Quality Standards triggers the
planning and control program development and implementation requirements
of Section 110 of the Act. The promulgation of National Ambient Air
Quality Standards on April 30, 1971, for six pollutants* set in motion
the Act's planning and plan execution, process for achieving those
primary NAAQS by the mandatory 1975 to 1977 period.**
* Although NAAQS have been set for six pollutants, the standard for
hydrocarbons is to be used as a guide in devising implementation
plans to achieve the oxidants standard. The control of hydrocarbons
is treated in this document as a part of the oxidants control program.
** Since 1970, court decisions have helped define certain parts of
of the Act as follows: transportation and land use controls must
be included in SIPs where necessary to attain or maintain the
ambient standards; the control of indirect sources of air pollution
(such as shopping centers and highways) is an appropriate method of
reducing the direct pollution from the automobiles which they attract;
SIPs must prevent significant deterioration of air quality where the
air is now cleaner than the ambient standards; and constant emission
controls must be used to the maximum extent achievable in preference
to pollutant dispersion techniques.
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The Act places primary responsibilities for air pollution control
on the States. The development of control strategies by the States for
the achievement of NAAQS constitutes the essence of the planning process.
The State Implementation Plans (SIPs) set forth the control strategies
that will be followed and enforced by a State (within given time frames),
for achievement of NAAQS within specified geographic areas, i.e., Air
Quality Control Regions (AQCR). The SIPs are to specify the plan of
action for achieving the Act's objectives, i.e., reduction in emissions
levels requisite for meeting NAAQS and the prevention of excessive
increases in emissions in the future in order that NAAQS be maintained
and that significant deterioration of air quality be prevented.*
As a planning process, the SIPs are dynamic. Constant review and
necessary improvements of the plans are a part of this process. The Act
as well as EPA's implementing regulations include important features for
reviewing, updating, and changing plans for the purpose of accommodating
changing requirements (be they social or economic conditions, growth
patterns, or the changing status of technology), provided these are
consistent with the Act's essential requirements, i.e., the achievement
of air quality levels consistent with protection of public health and
welfare within specified time frames and the preservation of the nation's
air resources.
* The semi-annual reports on State progress provide summaries of the
status of each State plan. The report State Air Pollution Implementation
Plan Progress Report, January 1 to June 30, 1975, U.S.E.P.A. Office
of Air and Waste Management, Office of Air Quality Planning and
Standards, Research Triangle Park, N.C. 27711; September 1975 (EPA
450/2-75-008) contains detailed information on the status of each
SIP. Subsequent reports provide additional information.
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C. Overview of Status of Implementation of the Act's
Requirements and Future Actions
The highest priority Federal and State action has generally been
directed towards those Air Quality Control Regions where pollutant
concentrations exceed national standards which are protective of health.
The Agency has had the most success in carrying out those parts of the
law that involve the control of specific sources of emissions by the
application of a specific emission limitation. It has had less success
in trying to implement pollution control measures that involve very real
changes in lifestyles and land use patterns. These are changes that can
take place only over periods of time; they entail very basic social,
economic and environmental choices and tradeoffs which can best be made
by the people involved, i.e., through the political process at the
State, local and regional levels.
In some areas, the standards cannot be attained in the mandatory
time period with all achievable control measures. In some Air Quality
Control Regions, the level of social and economic change which may be
required to meet ambient standards on time is unacceptable in the near
future, in terms of economic and social impact. In other areas, there
are problems associated with deficiencies in the SIPs1 provisions for
attainment and/or maintenance of the standards, or with the degree of
source compliance with requisite emission limitations. The net effect
has been that many areas have not attained the standards by the statutory
deadlines.
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In areas affected by control requirements having a severe economic
and social impact, the Act provided only limited flexibility: Two-year
extensions of time for a given Air Quality Control Region and an additional
one-year extension for compliance of specific sources (or classes of
sources) with plan requirements. The strict time-tables imposed by the
Act and the limited discretion provided were the result of Congressional
decisions that progress in controlling air pollution would only be made
if stringent criteria for performance were imposed.
In areas that are not attaining standards due to SIP or SIP imple-
mentation deficiencies, actions for the near future have to concentrate
3
on defining and implementing requisite solutions (i.e., additional
enforcement activity and derivation and implementation of better control
plans). Control actions aimed at the prevention of future problems
(e.g., new source controls) and aimed at the development of control
measures (or other solutions) for problems which have been recently
documented (e.g., long-range transport of air pollutants), should also
be implemented expeditiously.
One major future challenge in air pollution control is to deal
effectively with the issues of growth—the issues involved in trying to
preserve and maintain air quality—and to relate and reconcile different
environmental concerns such as clean air with social and economic
concerns such as housing, jobs, and energy. This issue involves
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an increasing shift in emphasis from the abatement to the prevention of
pollution, including an increased emphasis on the control of those
pollutants likely to lead to future air pollution problems. The air
pollution issues associated with growth will require the development
of planning and control processes which recognize and accommodate the
extraordinary diversity of needs, conditions, and aspirations which make
up this country.
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D. Issues Related to the National Ambient Air Quality Standards
1. Overview
The key element in the control of air pollution under the air
quality management concept embodied in the Clean Air Act is the setting
of ambient air quality standards, since control requirements are derived
on the basis of calculations as to the emissions reductions necessary to
attain and maintain the ambient standards. Other systems for developing
control plans exist and are in use in other countries. In developing
the Clean Air Act, the Congress adopted this system as the one most
desirable for air pollution control in this country. This basic policy
decision of the Congress is not reassessed in this document. The Agency
does not believe that there is reason for a change in this basic policy.
Any consideration of NAAQS must-take into account the statutory
basis and the policy decisions made to develop the legislative mandates.
The Congress provided that public health protection should be of the
highest priority and that no other considerations enter into the setting
of the standards. The statute reflects this policy.* The Clean Air
Act, in Section 109, states that:
"National primary ambient air quality standards...shall be ambient
air quality standards the attainment and maintenance of which in
the judgement of the Administrator...allowing an adequate margin of
safety, are requisite to protect the public health...
* It should be noted that the consideration of other factors related
to the control of air pollution under the NAAQS, such as costs and
feasibility of control, may be taken into account as part of the
state control plan development process provided that the plan is
sufficient to attain and maintain the ambient standards; for this
purpose, the Act specifies that the Administrator is to provide
information to the States on control techniques.
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"Any national secondary ambient air quality standard...shall
specify a level of air quality the attainment and maintenance of
which in the judgement of the Administrator...is requisite to
protect the public welfare from any known or anticipated adverse
effects associated with the presence of such air pollutant in the
ambient air..."*
The Act specifies that the basis for setting the NAAQS be documented
in criteria documents. The issuance of a criteria document is to be
accompanied by proposed NAAQS, which are to be finalized within 90 days
of proposal. In the words of Section 108, the criteria are to:
"...Accurately reflect the latest scientific knowledge useful in
indicating the kind and extent of all identifiable effects on
public health or welfare which may be expected from the presence of
such pollutant in the ambient air, in varying quantities. The
criteria for an air pollutant, to the extent practicable, shall
include information on -
"(A) those variable factors (including atmospheric conditions)
which of themselves or in combination with other factors may
alter the effects on public health or welfare of such air
pollutant;
"(B) the types of air pollutants which, when present in the
atmosphere, may interact with such pollutant to produce an
adverse effect on public health or welfare; and
"(C) any known or anticipated adverse effects on welfare..."
On April 30, 1971, NAAQS were set for total suspended particulates
(TSP), sulfur dioxide ($02), carbon monoxide (CO), photochemical oxidants
hydrocarbons (HC) and nitrogen dioxide (N02). With the
Welfare effects are defined by Section 302 of the Act as including
but not limited to, "effects on soils, water, crops, vegetation,
manmade materials, animals, wildlife, weather, visibility, and
climate, damage to and deterioration of property, and hazards to
transportation, as well as effects on economic values and on
personal comfort and well being."
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exception of the criteria for nitrogen oxides, all other criteria
documents had been published prior to 1971.*
The basis for the NAAQS and the costs of attaining them have been
thoroughly assessed by various review groups. In general, these groups
have concluded that there is no basis for changing the NAAQS. The most
extensive recent reassessment was carried out by the National Academy
of Sciences (NAS) under contract with the U. S. Senate. The NAS,
although dissatisfied with the available data bases for setting standards,
concluded that:
"In general the evidence that has accumulated since the
promulgation of the Federal ambient air quality standards
by the E.P.A. Administrator on April 30, 1971, supports
those standards. Hence, on balance, the panels found no
substantial basis for changing the standards."
In relation to the implementing controls on motor vehicles, the NAS
stated that:
"Weighing all of these estimates, and their uncertainties,
we conclude that the benefits in monetary terms that could
reasonably be expected to accrue from implementing the
Federal statutory emission control standards for automobiles
are commensurate with the expected cost."**
*A portion of the criteria on S02 (effects on vegetation) was
revised in 1973, resulting in a change in the secondary NAAQS
for this pollutant.
** Air Qua1ity and Automobile Emission Control, A Report by the
Coordinating Committee on Air Quality Studies, National Academy
of Sciences-National Academy of Engineering, prepared for the
Committee on Public Works United States Senate, pursuant to
S. Res. 135 approved August 2, 1973. Volume 1, Summary Report,
September 1974. Serial No. 93-94, pages 1 and 3. U. S. Government
Printing Office, Washington, D. C. 1974.
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Similarly, the Agency's Science Advisory Board (SAB) found the standards
to be adequate.
The MAS and SAB findings indicate that there is no reason to change
the Agency's concerns with respect to pollutants covered by NAAQS.
Additional data that have become available since the publication of the
criteria documents confirm the need for control.
Pursuant to the advice of the National Air Quality Criteria Advisory
Committee, the criteria are being updated to incorporate recent findings
of research work. It is expected that the criteria will be revised in
the following order: photochemical oxidants and related organic substances;
nitrogen oxides; carbon monoxide; and sulfur oxides and particulates.
Draft revisions are expected to be available starting in late 1977 and
extending through 1980. The revisions of the criteria documents will
result in an improvement of the data base available in support of the
standards. If the evidence so indicates, the Agency will initiate
actions for revising the NAAQS.
Although the current standards are judged to be necessary and
proper, the Agency recognizes issues associated with them. A summary
discussion of the issues associated with particulates, oxidants, and
nitrogen dioxide is provided below. The issues related to carbon
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monoxide and sulfur dioxide* are limited to those related to the implementation
of controls; these issues are discussed later in this document. Since
evidence exists that some of the effects ascribed to TSP and/or $03 may
be due to sulfates, a short discussion of sulfates and SC^ is also
provided.**
2. Total Suspended Particulates
The issues associated with the total suspended particulates (TSP)
NAAQS are related to the health effects associated with the non-specific
complex known as TSP, and the difficulty in developing control measures
for certain sources of particulates that have not traditionally been
associated with air pollution control programs.
The NAAQS are set for total suspended particulates which is opera-
tionally defined as the material that is captured on the filter of a
high volume sampler. In general, particulates of concern are those in
the respirable size range (i.e., those that can penetrate
* In relation to sulfur dioxide, it should be noted that the recent
public controversy on the use of data from the Community Health
Effects Surveillance Studies (CHESS), although widely publicized, has
no bearing on the validity of the NAAQS for sulfur oxides or on
EPA's standard-setting process. Exhaustive investigations carried
out by Congressional committees and the EPA have not substantiated
the allegations made in the press in relation to the conduct of
the studies or the publication of the findings. In any event, the
CHESS investigations have no bearing on the current NAAQS since
the CHESS were initiated after the NAAQS were set. The CHESS data,
along with all other relevant data, will be used for updating
the criteria documents.
** For information on the effects of air pollutants, the reader is
referred to the publications listed in Appendix A.
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deeply into the lungs and be deposited there). The high volume
measurement method, however, does not discriminate between respirable
and non-respirable particles. This factor becomes a matter of concern
where large quantities of particulate matter are collected by the
sampling method during dust storms, leading to violations of the NAAQS.
Although these natural emissions and associated air quality levels can
be discounted from total ambient pollutant loadings where they can be
documented, available information indicates a distinction between
natural and other sources of particulates cannot be readily made.
Another dimension of particulate-related issues is that of the
actual composition of the particulate. There is health effects evidence
that incriminates specific substances as being responsible for observed
health effects currently ascribed to total suspended particulates.
Examples of such substances are sulfate, sulfite, nitrate, heavy metals,
and polycylic organic matter. Controls for each of these substances
cannot be set at this time, although the Agency is proceeding to develop
the requisite data for setting appropriate standards (e.g., sulfates)
or has already initiated control action for a specific substance
(i.e., lead).
Certain sources of particulates present a third category of issues.
Difficult to control sources can contribute significantly to TSP levels.
Examples of these types of sources are the "urban particulate background,"
the natural sources mentioned earlier, fugitive emissions, and the
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formation of participates in the atmosphere as a result of photochemical
or other reactions involving gaseous substance emissions. These
problems are addressed to a very limited extent by existing SIP
control strategies.
The control of "urban particulate background," such as particulates
emitted by automobiles and resuspended dust from roads, is of a long-
term nature, to be addressed in the future. Longer-term or more
difficult solutions, such as the reduction of secondary particulates
formation, must await the implementation of controls for specific
pollutants (e.g., oxidants, sulfates) or the development of long-term
air quality maintenance plans which can take into account these problems.
Fugitive emissions from stationary 'sources generally escape to the
atmosphere in ways other than through'a primary exhaust system or are
more directly emitted to the atmosphere from industrial processes that
operate out-of-doors, such as coke ovens and rock-crushing operations
at quarries. Fugitive emissions also result from poor maintenance of
process equipment and from careless process operations. Once captured,
fugitive emissions can be ducted to available emission control systems,
such as baghouses for particulates and scrubbers for gaseous pollutants,
where they can be effectively collected. A regulatory approach which
requires the elimination of or the capture and cleaning of fugitive
emissions is the recommended control strategy for control of fugitive
particulate emissions at the present time.
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Fugitive dust emissions from natural or non-point sources* are found
in the more arid areas of the nation, such as the Southwest, and also
where farming operations and unpaved roads are prevalent. Windblown
dust (both natural dust and soil exposed by man, e.g., farms, roads)
and dust generated directly by man's activity (e.g., driving on unpaved
roads), creates high ambient concentrations of particulate matter. The
control strategies determined necessary to attain national standards
in AQCR's impacted by fugitive dust generally indicate that unconventional
air pollution control techniques may be required, such as:
. Chemical stabilization of soils;
Implementation of soil management control programs;
. Paving of more heavily traveled unpaved roads in generally
urbanized portions of AQCRs;
Speed control on all unpaved roads; and
. Stabilization or watering of construction sites, material
storage piles, tailing piles, and animal feedlots.
These fugitive dust control strategies have not been fully
implemented because they include some controls that are considered to
be socially disruptive and unreasonable. Some of the areas which would
* The term "fugitive dust" should be distinguished from the term
"fugitive emissions." "Fugitive emissions" generally refer to
industrial process emissions which do not pass through a
stack or chimney.
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have to implement these control measures for fugitive dust control also
tend to be impacted by high particulate levels resulting from natural
wind-blown dust from storms.
3. Sulfur Dioxide and Sulfates
The issue associated with sulfates is whether or not the health
effects currently ascribed to sulfur dioxide are actually related to
sulfates in general, or perhaps, to specific sulfur-containing compounds,
such as sulfuric acid, zinc ammonium sulfate, ferric sulfate, and cupric
sulfate. The significance of this is that sulfates tend to be more
persistent in the atmosphere than S02 itself, and much of a 24-state area
in the Northeast has sulfate levels approaching or exceeding the ambient
concentrations which may be associated with health effects even where
S02 levels are meeting the S02 NAAQS: In addition, there may be synergistic
health effects associated with the action of sulfates and other pollutants.
The sulfate issue is further compounded by the long-term environmental
effects that are suspected but not yet proven, such as acidification of
rain. The information currently available is sufficient to cause concern,
but not sufficient to warrant specific regulatory action.
EPA's policy on sulfates (outlined in the September 1975 Position
Paper on_ the Regulation of Atmospheric Sulfates*) recommends 1 imiting
* U. S. Environmental Protection Agency, Office of Air and Waste
Management, Office of Air Quality Planning and Standards, Research
Triangle Park, North Carolina 27711; EPA - 450/2-75-007
September 1975.
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increases in SOX emissions. Health effects studies are continuing, but
the complexity of the problem is such that standards specific to sulfates
will probably not be set prior to 1982. EPA's policy recommends limiting
any SOX emission increases in a broad 24-state area of the heavily
industrialized eastern and northern states until better data are collected
on the adverse health effects of sulfates.
4. Photochemical Oxidants
Issues associated with the NAAQS for photochemical oxidants are
related to regional transport, natural ozone levels, the components of
photochemical oxidants other than ozone, and the relationship between
hydrocarbon emissions and photochemical oxidants in the ambient air.
A significant new dimension is added to the oxidant air pollution
problem by two recently acknowledged factors: It appears that all non-
methane hydrocarbons and other reactive organic substances eventually
participate in photochemical reactions, and oxidant precursors are
transported large distances in stagnant air parcels associated with high
pressure systems. Although oxidant (and precursor) transport has been
identified as one of the causes of ambient air quality levels in excess
of NAAQS in some areas, it should be noted that the primary cause of
violations of the NAAQS is the emission of oxidant precursors in the
area where high readings are found. The oxidant levels measured
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in or immediately downwind of a major urban area are principally due
to emissions in that urban area, not to rural emissions or emissions
from other urban areas upwind. Control within broad urban areas will
continue to be most effective in reducing peak oxidant levels.
The mechanism postulated for oxidant transport is as follows:
As high pressure systems travel through the U. S. in the summer, they
provide ideal conditions for oxidant formation—large amounts of HC
and NOX are injected into the air mass by the multiplicity of sources
in these areas (both urban and rural), extended time periods are
provided for all HC to participate in photochemical reactions, the
high temperatures and insolation associated with these systems enhances
photochemical reactions, and little opportunity exists for dissipation
of oxidants formed. In brief, these atmospheric systems enhance
photochemical reactions and impede natural cleansing of the atmos-
phere. In addition, evidence indicates that all non-methane hydrocarbons
and other reactive organic substances eventually react photochemically
if given sufficient time to react. (Studies in the past had concen-
trated on limited timeframes and limited geographical areas.) This
means that all non-methane hydrocarbon and other reactive organic
substance emissions are of significance for the control of photochemical
oxidants, and that emissions in one city or area can result in high
oxidant levels in other areas or cities.
EPA is currently attempting to better define the nature and
magnitude of precursor transport, but the implications for control
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programs are clear: control programs will have to consider and
encompass wide geographic areas,and all sources of photochemical
oxidant precursor emissions may have to be abated. Although the
adequacy of our understanding of emission reductions required to
attain NAAQS for oxidants is not as good as would be desirable
(current techniques being less than ideal for deriving control require-
ments*), it is clear that reductions of HC emissions lead to improvement
in oxidant air pollution. Trends in the Los Angeles area (which has
available the largest data base on oxidants) and laboratory data
support this conclusion. Therefore, EPA's strategy for oxidant control
is to reduce hydrocarbon emissions whenever it is feasible- Oxidant
control plans are to focus on the areas responsible for the greatest
proportion of hydrocarbon emissions, i.e., urban areas. (States can,
if they so choose, extend controls for hydrocarbons to areas outside
the urban concentrations which are the focus of EPA's strategy.)
* The factors which determine the concentrations of oxidants formed
in the atmosphere include: the amount and kinds of organic
compounds initially present and the rate at which additional
organics are emitted into the atmosphere, the amount of nitrogen
oxides initially present and their emission rates, and sunlight
ultra-violet intensity, temperature, and other meteorological
factors. The interactions of these factors and the chemical
reactions involved are very complex and have been the subject of
continuing scientific investigation during the last 20 years,
including atmospheric studies, laboratory smog chamber studies,
and computer simulation of the oxidant forming process. Nitric
oxide (NO) is the major form of nitrogen oxide emitted in combustion
processes. Nitrogen dioxide (N02) is formed from NO and is the
compound which decomposes in sunlight to initiate the formation of
ozone. Because the relationship between hydrocarbon emissions and
oxidant concentrations is dependent on so many factors, various
attempts have been made to develop a simplified relationship. These
bases for control strategy derivation are not discussed in this
document.
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It should be noted that in many cases SIPs do not provide for
oxidant precursor control for areas violating NAAQS since data on
ambient air concentrations of oxidants were not available at the
time of plan preparation. Furthermore, current SIP control strategies
for the attainment of the oxidant NAAQS were developed on the assumption
that local high readings of oxidants were the result of precursors
emitted in the area surrounding the monitor reporting the high readings.
The new data on air quality and photochemical oxidant formation indicate
that very complex and far-reaching control programs will have to be
developed if the standards are to be attained in the future. The
clear implication is that controls probably will be required on a
much broader geographic scale than has been the case to date.
In urban areas, the ratio of hydrocarbons to nitrogen oxides
tends to be low so that changes in levels of photochemical oxidants
locally generated are quite sensitive.to changes in the levels of
hydrocarbon present. Thus, hydrocarbon emission control programs
would be expected to be effective in reducing the amount of photo-
chemical oxidants locally generated in the urban area, thus also
reducing the amount transported to neighboring rural areas.
An investigation is underway to determine the extent of the
geographical area around urbanized locations where hydrocarbon
emission control programs will be most effective in reducing photo-
chemical oxidant levels. Early findings of this investigation
indicate that these areas may be proportional to city size and may
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extend up to 85 miles from major metropolitan areas. In addition,
upwind-downwind measurements around smaller urban areas and isolated
point sources of hydrocarbons and nitrogen oxides indicate that there
is little if any increase in observed photochemical oxidant concen-
trations as a result of the emissions from such smaller urban areas
and isolated point sources. Although very limited data are available,
it appears that urban areas with a population less than 200,000
produce little, if any, measurable increase in photochemical oxidant
levels.
In view of the widespread nature of oxidant problems, emphasis
for setting new source performance standards for stationary sources
is being shifted to sources of oxidant precursors. Mobile sources
controls also concentrate on this objective—all significant mobile
sources of HC and NOX emissions are in the process of being covered by
stringent standards applicable to new sources. However, new source
controls will not lead to attainment of the standards in many areas
of the nation, nor is there assurance that purely technological
solutions will lead to requisite emission reductions to attain and
maintain the NAAQS. A rethinking of many of the ways in which
transportation sources are used is required, as well as long-term
consideration of the air pollution impact of the sources of hydrocarbons,
An additional issue encountered with the NAAQS for photochemical
oxidants is the low value of the standard (0.08 parts per million,
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one hour average) when compared to reported natural background values,
which range in the order of 0.04 to 0.06 ppm. It has been argued that
many areas with reported violations of the NAAQS are violating NAAQS due
to natural causes (due to ozone formed from natural HC sources, such as
forests, or due to ozone advected from the stratosphere), and, therefore,
that no control actions are possible. Whatever merit these arguments may
have, levels in excess of the NAAQS are generally related to human
sources of photochemical oxidant precursors, so the need for HC controls
will not be diminished.
Another issue is related to the measurement of oxidants. The NAAQS
for photochemical oxidants were established on the basis of evidence
related to the health effects of oxidants; the currently accepted
Federal Reference Method (FRM) for ambient air quality monitoring of
oxidants is specific for ozone, one of the components of photochemical
oxidants. (The oxidant found in largest amounts is ozone; oxidants also
include the group of compounds referred to as PAN, or peroxyacetyl
nitrates, and other compounds produced in much smaller quantities.) It
has been argued that ozone, by itself, is a poor proxy for the complex
known as photochemical oxidants, and that control plans derived on the
basis of measurements made with the FRM are not necessarily justified.
However, it should be noted that ozone measurements are closely related
to measurements for total net oxidants.*
* Air Quality Criteria for Photochemical Qxidants, U. S. DHEW,
NATCA, March 1970, Publication AP-63.
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5. Nitrogen Dioxide
The review of the NAAQS indicated that a possible deficiency of the
N02 NAAQS was the lack of a short-term standard for protection against
the effects of peak levels of this pollutant. Current evidence suggests
that the ambient air quality standard should include a limitation on
peak levels of exposure; the data suggest that the limitation should be
on repeated peak levels rather than a limitation on one peak per year,
but the health effects data base is not yet sufficient to warrant control
action on this basis. The short-term standard is expected to be in
addition to the current annual average standard, which will continue to
be used to assess plan adequacy and to implement controls for NC^-
E. Monitoring Air Pollution
Proper judgments about the attainment and maintenance of the
NAAQS can only be made with data obtained from an adequate monitoring
program. It is essential that strategies for the control of pollut-
ants also include monitoring of these pollutants. Monitoring covers
those activities which are related to establishing the concentration
or quantity of a pollutant. These activities include ambient air
monitoring, source emission monitoring, and dispersion modelling.
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In recognition of the critical role that monitoring plays in
air quality management decisions at all organizational levels, EPA
has established the Standing Air Monitoring Work Group. The Work
Group has reviewed air monitoring activities performed in support
of SIP's and has developed an overall monitoring strategy which,
when fully implemented, should correct identified problems and
improve current monitoring operations. (The final strategy
document is to be available by summer 1977.) The implementation
of this strategy is intended to be phased over a five year period
since it is recognized that rapid changes to on-going monitoring
programs entail the risk of decreasing the effectiveness of con-
trol program activities dependent on monitoring data.
The monitoring strategy emphasizes the need for quality
assurance. Since the quality of the monitoring data has profound
impact and implications on the soundness of pollution control
decisions, the implementation of a minimum quality assurance program
for both source and ambient air monitoring activities is to be given
greater emphasis. The goal is to assure that all agencies involved
in air monitoring use the best available instrumentation and quality
assurance techniques within their limited resources.
Key changes in air monitoring are directed towards increasing
EPA's and State/local agencies' ability to make decisions concerning
attainment and maintenance of the NAAQS through a refined ambient
air monitoring program. These changes are to be made after a
comprehensive review of existing state air monitoring networks.
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The strategy recommends that as a result of this review, a small
core of fixed National Air Quality Trend Stations operated by
State and local agencies be established. Data from these stations
will in most cases be adequate to meet EPA HQ minimum needs for
determining trends and evaluating and developing national control
policies.
Since the national trend stations will meet only a part of the
State and local agency needs for air monitoring data, additional
sites will be operated by these agencies as required. These moni-
toring sites will be used to supplement the national trend site data
and provide for more complete geographic coverage, especially in
non-attainment areas. The sites comprising this network would be
reviewed annually as to the need for relocation. All monitoring
performed apart from these fixed networks would be flexible and
thus easily adaptable to changing priorities and needs of the
State and local agencies. This type'of monitoring should enhance
the usefulness of the fixed station data by increasing the coverage
,•
of that network for short time periods and by producing data where
none existed previously or where data are no longer valid.
In the future, State and local agencies will need to rely more
heavily upon dispersion models to augment their capabilities to
predict the impact on air quality of individual sources or source
categories. This is especially important to support activities
involving new source reviews. Multi-source urban dispersion
modelling can also be used to evaluate effectiveness of proposed
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SIP revisions and, in conjunction with population distribution infor-
mation, is an extremely valuable tool in estimating the exposure of
the population to levels above the ilAAijS. This latter effort is
valuable in displaying information to the public in a readily under-
standable manner as well as providing a good measure of the success
of control programs.
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II. Status of Air Pollution Control and Future Actions
A. Overview of Progress to Date
The air has become measurably cleaner since 1970.* Reductions
in emissions have resulted in improvements of ambient air quality in
terms of the actual levels of air pollutants in the air and in terms
of the number of times that the NAAQS are exceeded. Both of these
measures indicate that population exposures to unhealthy levels of air
pollution are decreasing. Although standards are not universally met
at this time, important reductions in population exposure have been
achieved. Continued progress in reducing population exposures is
expected in the future and is the focus of control programs.
The concentration of particulate"s in the ambient air has decreased
annually at an average rate of 5 percent through 1975. A review of
the most recent sulfur dioxide ambient data shows that concentrations
in urban areas have decreased an average of 30 percent since 1970.
Fewer than 10 percent of all urban monitors are exceeding the sulfur
dioxide standards.
For carbon monoxide, associated mainly with motor vehicles,
historical data are limited. Available data in the several States
* Additional material on environmental status is available in
National Air Quality and Emissions Trends Report, 1975, U. S.
E.P.A., Office of Air and Waste Management, Office of Air
Quality Planning and Standards, Research Triangle Park, North
Carolina 27711; November 1976 (EPA-450/1-76-002). This report
is issued annually.
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and major cities suggest a continuation in the general improvement
noted previously in EPA trend reports. The average number of occa-
sions in which 8-hour concentrations exceed the carbon monoxide
standard has declined, typically by 50 percent in many of the urbanized
portions of these States.
Historical data on oxidants, which are produced largely by
hydrocarbon and nitrogen oxides emissions from both stationary and
mobile sources, are non-existent in all but a few urban areas. Los
Angeles and San Francisco have shown notable improvements where the
number of hours in excess of the oxidant standard has been reduced
by as much as 50 percent since 1970 at many of the monitoring stations.
(It should be noted that California has imposed stringent HC emission
control programs.).
Nitrogen dioxide emissions have increased nationally about 10
percent since 1970. Because of recent changes in measurement methodology
for monitoring nitrogen dioxide, few areas have sufficient historical
data to assess trends. Valid data indicate that only a few areas of
the country have ambient nitrogen dioxide concentrations in excess of
the national standard.
Although significant progress has occurred, many problems remain.
The solutions to these problems affect fundamental activities of the
nation such as power generation, industrial production, transportation,
and agriculture. Some pollutant levels can be reduced through better
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compliance with existing regulations. Others require new and
innovative revisions to existing control strategies.
Particulates and sulfur dioxide are predominantly associated with
stationary sources of pollution. Approximately 22,000 major indus-
trial emitters (those capable of emitting over 100 tons of pollutants
each year) account for about 85 percent of the stationary source air
pollution. By July 1977, EPA expects over 90 percent of these major
emitters to be in compliance with existing State Regulations. For
particulate matter, numerous small sources in urban centers require
control. Some areas will require control strategies beyond the
classic stack controls, including controls of fugitive emissions,
other particulates, and fugitive (windblown) dust. For sulfur dioxide,
non-attainment results primarily from'delayed implementation of
existing regulations for emissions from power plants and non-ferrous
smelters.
For photochemical oxidants, strategies are based on controls of
hydrocarbon emissions from both stationary and mobile sources. Oxidant
and carbon monoxide concentrations are expected to improve somewhat
in most areas of the country as controlled automobiles replace older,
uncontrolled vehicles. Even with substantial improvement in air
quality for oxidants and carbon monoxide, however, a large number of
AQCRs are expected to experience violations of the ambient standards
during the next 10 years. Additional urban areas will require
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transportation control measures in order to attain standards even by the
mid-1980's.
For nitrogen dioxide, the typical problem, where it does exist, is
in an urban area where observed nitrogen dioxide concentrations are
either slightly above or below the standard. Such conditions generally
represent a problem for maintenance rather than for attainment of the
standard.
B. SIP Revisions
Actions taken by EPA and the States with respect to non-attainment
areas involve a mix of actions aimed at continued implementation of
emission reduction provisions of the SIPs, at identifying areas which
require revisions of the SIP, and at revising the SIPs where current
SIPs are found to be substantially inadequate to attain the NAAQS. The
process involves identifying non-attainment AQCRs, identifying the
factors that result in non-attainment, developing plans for corrective
action, and implementing the corrective actions.
Initial calls for SIP revisions were issued by July 1, 1976, for
SIPs which were determined to be substantially inadequate to attain the
NAAQS. Calls for SIP revisions were issued as follows:
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Pollutants for Which a
Plan Revision Is Required
ISP. sp_2 co gx
Number of States issued
a call for revision* 31 12 22 29
* Appendix E identifies the specific States.
The indication that a State needs a SIP revision does not necessarily
indicate that conditions exceeding the national ambient standards prevail
throughout the State. The calls for revision indicate that a State has
to reassess its air pollution problem and develop, if warranted, addi-
tional control measures for attaining standards. In addition, special
planning procedures must be followed for 119 areas identified as air
quality maintenance problem areas.
The State implementation plan revisions now being required are
subject to two submission dates. First, if needed, all achievable
emission limitations must be submitted as SIP revisions no later than
July 1, 1977. The term "achievable" is intended to require reasonable
"technology forcing" regulations if necessary, rather than regulations
based simply on "off-the-shelf" technology. Second, all other measures
needed to attain and maintain the NAAQS must be submitted no later
than July 1, 1978. These "other measures" should be comprehensive and
innovative where needed, and may include items such as land use measures,
transportation controls, transit improvements, zoning ordinances,
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building codes (such as to increase insulation, thereby decreasing
energy use), and inspection/maintenance programs (for stationary
and/or mobile sources). This schedule for plan revision is under-
going revision as EPA and the States determine the actual controls
required. Some delays beyond these dates are to be expected in the
process for plan revision, especially in relation to oxidants.
By 1978, it is expected that all achievable control measures
would have been identified if required for the attainment of the
NAAQS, that a plan for the implementation of these measures will have
been submitted by the states and approved by EPA, and that the process for
identification and adoption of the measures requisite for the maintenance
of the standards will have been implemented. Beyond 1978, actions
would be related to the implementation of the control plans. It is
expected that a relatively greater emphasis will be placed in this
time period on new sources, both for purposes of prevention of air
pollution (including prevention of significant deterioration) as well
as the maintenance of NAAQS.
C. Emission Reductions from Sources — Issues and Policy
1. Introduction
The preceding discussion of issues associated with the NAAQS
highlighted the factors that affect the current status of the national
air pollution control program and that have dictated the Agency's
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strategy in implementing the Clean Air Act. The currently documented
widespread need for revisions of the SIPs reflects the improved under-
standing, developed over the last few years, as to the factors that
affect air quality and the actions that still must be taken if the
environmental protection goals are to be achieved. Another factor that
has contributed to the lack of attainment of the standards has been the
lack of action on the part of pollutant sources in reducing emissions.
The significant issues that have impeded full implementation of these
controls are examined below.
2. Total Suspended Particulates and Sulfur Dioxide
The stationary sources of particulates and sulfur oxides (e.g.,
factories, power plants, home heating) have traditionally been the
focus of air pollution abatement efforts since these sources have been
recognized as responsible for the bulk of the particulate and sulfur
dioxide air pollution. Based on an overall assessment of the status
of compliance of sources and the need for corrective actions, EPA
generally has placed highest priority on the implementation of control
requirements for sources of sulfur oxides and particulates. This
emphasis has resulted in the improvements in air quality indicated in
the preceding section.
With a few minor exceptions (e.g., particulates emission limitations
for the State of Illinois) all states now have enforceable emission
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limitations for stationary installations.* Except for portions of
16 States (where extensions of up to 2 years were granted for one or
more pollutants), the primary National Ambient Air Quality Standards
were to be achieved by May 31, 1975, i.e., substantially all sources
should have been in compliance with the SIP emission limitations by this
date. EPA, State, and local enforcement programs have focused first on
ensuring compliance by major emitters in order to produce the greatest
reduction in pollution levels with available resources. Despite progress
in SIP enforcement, a number of facilities within major source categories
have not achieved compliance with emission standards within the time
limits prescribed by the Act. Notable among these source categories are
coal-fired power plants, iron and steel manufacturing plants, and
smelters; these sources are discussed below.
In addition to the problems caused by continuing violations by
classes of heavy industrial emitters, it is becoming increasingly apparent
that in many areas of the country poor air quality is the result of
large numbers of violations by smaller emitters (i.e., less than 100
tons per year). EPA and States are conducting analyses of non-attainment
AQCRs to identify those where minor sources are responsible for delays
in the attainment of health-related air quality standards so that enforce-
ment efforts and adoption of adequate regulations can be initiated where
needed.
* On the order of 200,000 stationary sources are subject to SIP emission
limitations. Of this number, approximately 22,000 are major emitters.
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Furthermore, it is clear that, in many cases, traditional control
of stationary sources (e.g., limitations placed on emissions from a
smokestack) will not suffice to attain and maintain the NAAQS. Ambient
air loadings of particulates often are significantly influenced by other
than stack emissions: the formation of particulates in the atmosphere
from gaseous emission; the contributions from motor vehicle exhausts;
the re-entrainment of dust from streets; and dust-producing activities
such as construction, unpaved roads, and farming operations. These
issues are discussed earlier, under the TSP NAAQS section.
In relation to sulfur dioxide, shortages of low-sulfur-content fuels
and the national policy of reducing reliance on insecure foreign sources
of petroleum will result in the utilization of higher sulfur content
fuels (e.g., coal rather than fuel oil, fuel oil rather than natural gas)
in the future. EPA views these developments with concern since they have
potential for aggravating sulfur dioxide air pollution problems as well
as increasing the resulting atmospheric loading of sulfates.
a. Primary Non-Ferrous Metals Smelters
The nation's 25 non-ferrous smelters account for about 10 percent
of the total sulfur oxides emitted by stationary sources. Regulations
for control of smelters located in several States* were proposed by
EPA in 1972. Numerous court suits were filed by the individual non-ferrous
* These states are Arizona, New Mexico, Nevada, Utah, Idaho and Montana.
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metal smelters against both the proposed regulations as well as
subsequent final rulemaking. The issue involved is the degree to
which utilization of Supplementary Control Systems (SCS) and increased
stack height is to be permitted and the amount of emission reductions
that should be required through the application of constant emission
reduction systems.
The regulations applicable to smelters require application of best
available control technology (BACT) as a long-term goal, but during
the interim permit the use of reasonable available retrofit control
technology (RACT) and, if necessary, also allow the interim use of SCS
and tall stacks until BACT-calibre techniques that are less costly than
those that exist today become available. Each smelter using SCS is
further required to accept liability for NAAQS violations in its area
of liability and to conduct a research and development program to hasten
the development of less-costly, BACT-calibre emission reduction technology.
For some smelters, the alternative to the use of SCS and RACT would
be economically unrealistic. This industry is mostly composed of older
plants and is. in competttion with foreign smelters. EPA has taken into
account the specific problems affecting this industry. Thus, special
dispensation has been granted and EPA, for the interim, is not requiring
that NAAQS be met solely through emission reduction techniques. It
should be noted that, in general, EPA is not requiring any changes in
process equipment,as would be required in many instances if BACT-calibre
equipment were the present-day standard. EPA is requiring only that
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RACT emission control facilities be installed and maintained and, for
the interim, is also allowing SCS to be used for gas streams that would
otherwise require BACT-calibre control equipment. In all events the
control strategy permitted must demonstrate attainment and maintenance
of national ambient standards.
b. Iron and Steel Mills/Coke Plants
The iron and steel industry presents one of the most difficult
compliance problems for state and Federal air pollution enforcement
programs. There are about 246 steel and coke-making installations in
the United States, of which 218 produce iron and steel (and may or may
not produce coke). The remainder solely produce coke to be used in
metallurgical and other industries. Nearly all of these installations
are located in areas where the primary NAAQS have not been attained. At
least one SIP emission limitation is being violated at almost every
installation.
The steel industry is characterized by less than half the degree of
compliance of all major sources. Although the iron and steel industry
industry faces difficult problems in meeting emission limitations and,
in general, in complying with air pollution control requirements, this
industry generally has failed to make reasonable progress in controlling
air pollution. The Agency judges the lack of progress to have been
caused, in many cases, by industry failure to do what is achievable
rather than the magnitude of the task facing the industry. However, there
are substancial differences in control levels from company to company,
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and significant recent progress has been made at a number of iron and
steel mills. The Agency will continue to concentrate its enforcement
efforts to assure that iron and steel mills come into compliance with
SIP requirements.
c. Coal-Fired Power Plants
Coal-fired power plants account for approximately 55 percent of
sulfur air loadings. By mid-1973, it became evident to EPA that many
coal-fired power plants were not making plans to comply with sulfur
oxide emission limitations because supplies of low-sulfur coal (the
favored approach to compliance with emission standards) were becoming
scarce, and the principal alternative means to compliance, the stack gas
scrubber, was viewed by the industry as unreliable. National public
.hearings were held in the fall of 197-3 to determine the validity of the
utilities' contentions regarding optional means of compliance. The 1973
hearing panel concluded that the basic technology problems associated
with flue gas desulfurization (FGD) had been solved or were within the
scope of current engineering and, further, that FGD could be applied at
reasonable cost. A special EPA enforcement program was then initiated
for power plants on the basis of these findings.
EPA recognized, when it approved the State Implementation Plans,
that there would be shortages of acceptable coal if all the States
enforced their control regulations. To alleviate this potential shortage,
EPA developed a policy (the "Clean Fuels Policy") of encouraging State
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review of plans in order that sulfur emission limits be modified
whenever this could be done without exceeding the primary air quality
standards. A similar policy was adopted by the Congress in the Energy
Supply and Environmental Coordination Act of 1974 (ESECA). The policy
encouraged the States to analyze their control requirements in a more
detailed fashion than was generally done at the time of initial SIP
development. These actions are specific to each State, as the degree
of control required to achieve the primary standard varies widely
between air quality control regions and individual sources in each
region. Reviews of SIPs (required by ESECA) have been carried out. The
results have been submitted to the States for their consideration and
action.
d. Tall Stacks and Supplemental Control Systems
EPA's policy on the use of pollution dispersion techniques, such
as tall stacks and supplemental control systems (SCS)*, was published
in the Federal Register of February 18, 1976 (41FR7450). The policy
is also contained in a guideline to EPA regional offices on the
acceptability of tall stacks and SCS as part of the SIP control strategy
* The term "supplemental control system" means any system which limits
the amount of pollutant emission during periods when meteorological
conditions conducive to ground-level concentrations in excess of
national standards exist or are anticipated. SCS will be generally
effective only for isolated sources.
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for SC>2 control.* This policy is effective as of January 13, 1976.
The policy (derived pursuant to opinions rendered by three United
States Circuit Courts of Appeal), in essence, is that stack height
increases and/or SCS are acceptable control strategy measures only after
the application of other available control measures and are never permitted
as a means of allowing the increase of emissions at any source. Constant
emission limitation is the preferred strategy for attaining and maintaining
the national standards. For smelters and certain older power plants,
SCS is acceptable only as a temporary measure in conjunction with the
use of reasonably available control technology (acid plants for smelters
and coal washing for power plants) and only in circumstances wherein the
SCS can reliably attain and maintain the national standards. SCS is not
allowed for new sources.
The EPA guidance is used by the regional offices in reviewing plan
revisions and in re-evaluating existing State Implementation Plans to
determine whether any such plans have the potential for, or explicitly
permit, the use of dispersion dependent technology as a means of achieving
ambient air quality standards. The principles set forth in the document
will also be used in reviewing State new source construction permits.
* There is no guidance provided in regulatory format. Regulatory
action on tall stacks and SCS is part of the specific SIP approval/
disapproval and promulgation actions. The EPA guideline document
is Legal Interpretation and Guideline to_ Implementation of Recent
Court Decisions on the Subject of_ Stack Height Increase as a_
Means_ of Meetin'gTederal Ambient Air Quality Standards, 0"A~QPS
No. 3.0-003.
-------
There are generally three situations--!imited to SC^ emissions--
which permit the application of SCS:
(1) Under prohibition orders issued by_ FEA under the Energy Supply
and Environmental Coordination Act. Power plants required to convert to
coal must install control equipment and/or use fuel which would comply
with the SIP as expeditiously as possible. In the interim, ESECA
requires that the primary standards be met; an enforceable and reliable
SCS can be used to achieve this purpose when primary standards are
attained and coal which conforms with SIP requirements is unavailable.
(2) Under Enforcement Orders. When EPA issues an enforcement
order to a source to come into compliance with the SIP, it may be
necessary to require the source to apply an SCS for an interim period
in order to protect the ambient standards.
(3) AJ Part of an SIP Revision. Under this mechanism, a source
cannot operate an approved SCS unless a number of conditions are met,
including installation of Reasonably Available Control Technology (RACT)
e. EPA's Policy on SIP Revisions Aimed at Permitting
Use of Higher Sulfur Fuels
The energy situation, the economy, and to some extent the low S02
levels being reported in most areas are causing a number of States to
consider revisions to SIPs which will permit higher sulfur fuel to be
used in selected AQCRs. However, changes in fuel use will tend to
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increase emissions of sulfur, resulting in increased sulfate concen-
trations. Given the lack of a defined control requirement for sulfates,
the Agency cannot deny State requests for changing regulations appli-
cable to fuel sulfur content if the State demonstrates that the S02
standard will be attained and maintained. On the other hand, evidence
available to date indicates that the effect of sulfates may be as
important, if not more so, than the effects of currently controlled
pollutants. Therefore, the Agency views with concern the trend to
increase the emissions of sulfur to the atmosphere by the use of higher
sulfur content fuels.
EPA's policies and programs involving sulfates, significant
deterioration, tall stacks, SCS and New Source Performance Standards are
aimed principally at minimizing S0_ increases. The sulfate policy
recommends limiting any SC^ emission increases in a broad 24-state area
of the heavily industrialized eastern and northern States until better
data are collected on the adverse health effects of sulfates.
The prevention of significant deterioration regulations legally limit
SOp air quality increases by establishing constraints below the NAAQS
for S02-* The tall stack and SCS policies, recently confirmed by
Federal court decision, require the application of all available permanent
control measures before dispersion techniques can be used to attain
standards.
* It should be noted that a change to the use of fuels which lead to
increased emissions is not covered by the PSD regulations.
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On the other hand, the Clean Fuels Policy, which was initiated
early in 1972 for coal-burning sources, was an attempt by EPA to permit
continued burning of relatively high-sulfur coal, where this would not
lead to violations of the ambient standards, in order to release
presently limited supplies of lower sulfur coal for use in other, more
critical, areas. If a State emission reduction schedule prevented
continued burning of high sulfur coal that was adequate to meet the
NAAQS, the Clean Fuels Policy encouraged the State to revise its SIP to
make it legal. Congress reinforced and extended the philosophy of the
Clean Fuels Policy by its passage of ESECA in 1974. The intent of
Section 4 of ESECA was to encourage States to relax S02 emission limits
where possible without causing violations of the ambient S02 standards,
even if this means an actual increase in SCL emissions. The Clean Fuels
Policy and the ESECA legislation reflect a policy of cooperating with
States which want to relax emission constraints, provided that the S02
standard is attained and maintained.
Given the potential conflicts among the foregoing policies, the
general policy on SIP revisions which relax SCL emission limitations is:
First, the basis for approval must be whether the national primary
standards will be attained and maintained in accordance with the Clean
Air Act. The secondary standard must be attained within a reasonable
time. Second, EPA must cooperate with national energy programs to the
fullest extent possible consistent with the timely attainment and
maintenance of standards. Finally, in view of the concern over other
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pollutants and effects related to S02 emissions (e.g., sulfates,
secondarily formed particulate, and acid rain), rigorous demonstrations
that proposed SIP revisions will attain and maintain standards will be
demanded.
It is expected that the end result of these policies and activities
will be:to attain the current primary sulfur dioxide standards everywhere
as rapidly as possible; ensuring that the health effects from sulfate
particulates are minimized; electrical power generation capability will
not be disrupted; and domestic energy resources will be used. This
approach will also allow electric utilities to continue to use available
high sulfur coal production to meet the nation's energy demands where
such fuel will not cause violations of NAAQS.
3. Photochemical Oxidants, Carbon Monoxide, and
Nitrogen Dioxide*
a. Introduction
Motor vehicles are responsible for virtually all man-made emissions
of CO in all areas of the nation; they account for a variable (yet
substantial) proportion of hydrocarbon and NOX emissions (between 27
percent and 87 percent for hydrocarbons and 25 percent to 65 percent
for NOX). The control of CO, oxidants, and NOX is significantly
* For convenience, the pollutants will be referred to as CO (for
carbon monoxide) and N02 (for nitrogen dioxide). These pollutants
are also referred to as automotive-related pollutants due to the
predominance of motor vehicles as the principal emissions source.
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related to the control of motor vehicle emissions. However, the
variations in the contributions of sources for different areas of the
nation have resulted in the development of specific control measures
unique to each area.* Control strategies are primarily concentrated
on reducing emissions of photochemical oxidants precursors (i.e.,
organics**) and carbon monoxide. Somewhat lower emphasis has been
placed to date on the control of NOV (also an oxidant precursor***)
A
emissions due to the lesser magnitude of the N02 air pollution problem,
the reliance on organics control for achieving oxidant reductions, and
limited available control techniques.
EPA policy for control actions limits implementation to those controls
which are not economically or socially disruptive. Highest priority for
control has been given to attaining emission reductions from stationary
sources of HC through the application of Reasonably Available Control
Technology and the implementation of State motor vehicle emissions
inspection and maintenance programs for those areas for which SIPs
* In relation to automotive-related pollutants, it should be kept in
mind that SIPs are less well advanced in terms of development and
implementation of adequate planning processes and controls than
are the SIPs for TSP and S02.
** The principal sources of organic compounds are the hydrocarbon
emissions from automobile and truck exhausts, gasoline vapors,
paint solvent evaporation, open burning, dry cleaning fluids, and
industrial operations. There are also natural sources such as
seepage from the ground and emissions from vegetation.
*** Nitrogen oxides are emitted primarily from combustion sources such
as electric power generation units, gas and oil-fired space heaters,
and automobiles, diesel and jet engines.
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already provide for such measures. Adoption of control measures for
areas requiring SIP revisions will follow guidelines as to reasonableness
of control measures.*
b. Motor Vehicle Emissions Control**
Given the nature of the automobile industry and the universal use
•
of automobiles, the most effective point for controlling motor vehicle
emissions is by providing for the incorporation of controls into new
vehicles prior to sale to the ultimate user. The Clean Air Act provides
for a comprehensive control strategy aimed at the control of new
vehicles. '
The Federal Motor Vehicle Control Program (FMVCP) provides for a
cumulative improvement in ambient air quality (all other factors being
equal) as vehicles covered by increasingly stringent standards are
introduced and replace higher emitting cars. Full turnover of the
vehicle population requires about ten years. Therefore, although
significant emission reductions from motor vehicles may have already
been achieved, the statutorily mandated new motor vehicle emission
* A summary of these guidelines is provided in Appendix C.
** For background material on the motor vehicle emissions control
programs of the Agency, the reader is referred to the report
Progress in the Implementation pjf Motor Vehicle Emission Standards
June 1975"TU.S. EPA, Publication EPA 230/1-76-001; U. S. Government
Printing Office, 1976) which provides a good summary description of
the activities carried out for the control of motor vehicles and
presents the status of programs implemented to that date.
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reductions in CO and HC emissions impact only minimally on the ability
to meet ambient air quality objectives prior to the 1985-90 period in
the areas not currently attaining standards.
Growth of both the vehicle population and vehicle use, deterioration
of emission control systems on vehicles in use, the slow turnover of
the vehicle population, and changes in the date by which automobiles are
to meet statutory emission standards greatly reduce the impact of the
motor vehicle standards. However, it is also clear that the FMVCP will
have a significant impact on the achievement and maintenance of the
NAAQS in most areas of the country. In addition, in keeping with the
strategy of placing controls on new vehicles, more stringent controls
for heavy duty and medium duty vehicles, and controls for motorcyles
are being developed; these controls will further reduce the future air
pollution impact of these sources.
Available data indicate that many in-use motor vehicles do not
meet emission standards. It is clear that if in-use motor vehicles
met the emissions standards for CO through their useful life, the
problems related to CO air pollution would be solved relatively soon
through the operation of the Federal Motor Vehicle Pollution Control
Program. The failure of in-use vehicles to perform in a way that is
consistent with the intent of the emission standards appears to be
due primarily to a lack of proper maintenance; surveillance testing
of vehicles that were tuned-up prior to the emission test has shown
that tuned-up vehicles have mean emissions that do comply with applicable
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emission standards, whereas vehicles that were tested in their as-is
condition typically had mean emissions that exceeded some of the
standards. Other factors affecting emissions performance are deterior-
ation of the vehicles' emission control systems, real-world conditions
that are not properly accounted for by the Federal standards and the
associated testing and compliance programs, and tampering with emission
control systems. Recent data on 1975 model year in-use vehicles
indicate that CO emissions from such cars are in many instances sub-
stantially higher than had been anticipated. Similar problems have been
encountered with 1976 model year vehicles. The cause for such high CO
emissions has yet to be fully determined, but preliminary analysis
suggests that a major factor in these high emissions involves maladjustment-
whether accidental or purposeful—of idle mixtures and choke settings.
Such problems are amenable to correction by State programs (i.e., by
inspection and maintenance and anti-tampering programs, and mechanic
training). EPA expects that with the implementation of assembly-line
testing, an expanded recall program, the promulgation during the latter
part of calendar year 1977 of short-tests that (in conjunction with
inspection and maintenance programs) can trigger the warranty provisions
of Section 207(b) of the Clean Air Act, and the eventual implementation
of I/M programs, problems of maladjustment or tampering with vehicles
will be reduced sharply, and the expected degree of emission control
will be achieved in actual use. (It should be noted that in-use
performance of emissions controls for HC and NOY is not significantly
/\
different from that expected.)
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The Agency's strategy for motor vehicles emissions control is
to place the burden for compliance with emissions limitations, throughout
the useful life of the vehicle, on the manufacturers rather than the
owners of the vehicles. The Agency considers this the most effective
point of control. To this end, EPA is assessing the reasons for in-use
vehicle failure to meet emissions standards and will develop appropriate
corrective measures. As an initial step in this direction, EPA has
requested the manufacturers to correct deficiencies in the maintenance
procedures followed by the service organizations in the country and to
improve the manufacturers' recommended procedures for maintenance.
EPA intends to concentrate more thoroughly on reviewing the appropriate-
ness of manufacturers' maintenance instructions and intends to issue
maintenance regulations which define guidelines for acceptable maintenance.
The Agency also intends to expand its recall efforts to encourage
manufacturers to produce complying vehicles and through this enforcement
tool to foster greater maintainability of in-use cars. If warranted,
EPA will set appropriate regulations and additional requirements under
the certification process for prototype vehicles to correct deficiencies.
It is expected that these actions will result in a much improved service
industry capability for maintaining in-use vehicles according to
manufacturers' specifications and, by improving vehicle design, will greatly
increase the potential of vehicles for meeting emissions standards while
in actual consumer use.
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Although actions aimed at the manufacturers are expected to
result in future improvements in newer model year vehicles insofar
as in-use emissions performance is concerned, the totality of the
vehicle population will not be impacted by the actions taken at the
manufacturer level until approximately the early 1980's when new model
years (incorporating emissions control features which reflect the need
for in-use emissions performance that is improved over that currently
experienced) start to replace the existing vehicle population. In
addition, the Agency has no authority (except in the anti-tampering
area) to take action for improving emissions performance for vehicles
beyond 5 years or 50,000 miles since the Clean Air Act defines useful
life at these levels. However, typical vehicles last approximately
10 years or 100,000 miles. Only in-use control strategies are effec-
tive for the control of vehicle emissions from vehicles that are more
than 5 years old or have accumulated more than 50,000 miles.
It will only be in the late 1980's, at the earliest, that there
will be a significant impact from the Federal certification efforts at
improving in-use vehicle emissions performance. Additional action that
can be taken to improve emission performance of the vehicles that will
be on the roads up to that time will be in the area of improvements
in the maintenance of vehicles, recall of vehicles, and anti-tampering
activities. In this regard, State and local programs for improving
maintenance of vehicles, including their inspection and mandatory
maintenance if the inspection is failed, have a significant role to play.
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Reducing emissions from in-use vehicles can be achieved by two
types of actions: (1) Reductions in emissions by improved maintenance
or vehicle modification (e.g., recall fixes or retrofitting) for
achieving emission reductions from individual vehicles beyond those
achieved by the Federal (or California, for that State) standards for
new vehicles applicable to the specific model year, and (2) reductions
in total motor vehicle emissions by reducing the use, or vehicle miles
traveled (VMT)*, of all vehicles. VMT reduction measures, in general,
require changes in established patterns with respect to use of privately
owned passenger cars. Technological approaches to reductions in
emissions from individual vehicles require no changes in vehicle use.
Given the present and projected status of attainment of the NAAQS
with currently implementable new vehicle control strategies, the need
for the imposition of additional transportation control measures exists.
Some means of lowering VMT below current levels (and, for CO, reducing
congestion) will have to be 1n effect in some AQCRs indefinitely. CO
air pollution can be effectively reduced by the lessening of congestion
and other actions aimed at vehicle use related factors in addition to
inspection and maintenance,since CO is essentially a "hot spot" problem
related to concentrations of motor vehicles generally traveling at
speeds that are lower than average urban speeds. It is expected that
* VMT reductions are an alternative total emissions control measure
in addition to Individual vehicle emission reductions, since total
emissions are also a function of vehicle use as well as vehicle
emissions.
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States will address the non-vehicle emissions factors that affect CO air
quality through the Metropolitan Planning Organizations (MPO) and
transportation system planning processes. It is EPA's policy that new
and revised transportation strategies be developed by transportation
agencies, 1n coordination with air pollution control agencies, through
the normal urban transportation planning process. It is expected that
the SIP revisions will Incorporate improved transportation plans that
take Into account the air quality Impact of transportation-related
sources.
c. Motor Vehicle Emissions Inspection and
Maintenance
Motor vehicle inspection and maintenance (I/M) is a program of
periodic vehicle emissions inspection- and the mandatory performance of
maintenance for those vehicles found to emit excessive amounts of a
pollutant.* In a given metropolitan area with an inspection/maintenance
program in effect, the latest estimates indicate that the vehicle fleet,
on the average, will emit up to 50 percent fewer pollutants over several
years than would be the case without such a program. Initial reductions
of 24 and 37 percent are possible for HC and CO respectively. Depending
on the particular mix of stationary and mobile sources in an area,
Inspection/maintenance can obtain at least 6 to 18
* The amount found to be excessive is determined by the locality or
State carrying out the program. Emissions pass/fail points vary
with the model year of the vehicle; this is to take into account
the variations in the standards which the vehicles were built to
meet.
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percent of the needed hydrocarbon reduction and 20 to 40 percent of
the needed carbon monoxide reductions.*
Although I/M has not been widely implemented, largely due to
doubts as to its benefits and inconvenience it may cause the public,
the implementation of programs to date indicates their feasibility
and illustrates their financially self-supporting capability. For
example, in Arizona a franchised contractor operates the program for
the State without State funds being utilized in program operation.
In Arizona, as well as other areas, costs are recovered through inspec-
tion fees.
Given the need for achieving emission reductions of both CO and HC
from in-use vehicles, I/M is the highest priority program for control
of motor vehicle emissions under the SIPs. EPA considers this measure
to be implementable and effective in reducing motor vehicle emissions
and is proceeding with actions aimed at facilitating their implementation--
mechanics1 training is being supported; warranties for properly maintained
and used vehicles are to be implemented; and additional technical support
data are being developed.
* By serving as a check to insure that vehicles are maintained properly
throughout their lifetime, an inspection/maintenance program
contributes to the goal of reducing fuel consumption by motor
vehicles. The fuel savings to vehicles which are repaired in order
to pass the inspection check can be significant—fuel consumption
can be reduced by 4 to 10 percent on these cars.
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d. Control of Stationary Sources
Essentially no problems are presented by stationary sources of
CO. However, large amounts of hydrocarbons and other photochemically
reactive substances are emitted to the atmosphere as a result of
evaporation resulting from the storage, handling, use and transpotation
of hydrocarbon-containing substances as well as from the chemical
industry. Controls available for these emissions vary. Storage vessels
can be constructed and operated in a fashion such that emissions are
minimized and that economic benefits are accrued; an example of this
type of control is the use of floating roofs on tanks used for storage
of petroleum and petroleum products—net savings occur by keeping
valuable products from evaporating. (New source performance standards
for storage vessels require the use of floating roofs.)
Certain sources of organic substances, such as solvents (used for
dry cleaning and in paints), can be controlled by using substitutes
if they are available. Substitution of materials is based on the concept
of reactivity, i.e., certain types of organic substances tend to more
readily participate in photochemical reactions than do other types.
Control is based on substituting the less reactive organics for those
judged to be more reactive. (This approach has been extensively used
in the Los Angeles area.) However, more recent understanding of the
organics1 role in photochemical reactions (i.e., all organic substances
react photochemically if given sufficient time) indicates that the
substitution of one type of organic substance for another on the basis
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of reactivity considerations cannot be considered as a long-term
control strategy for oxidants control. The replacement of organic
substances with other substance, e.g., water based paints, is an
effective long-term strategy for reducing HC emissions. EPA will not
allow credit in the SIP control strategy for substitution of less
reactive organics for those considered to be more reactive.
The amount of control achievable by the foregoing techniques is
generally not sufficient to assure attainment of the NAAQS. Additional,
more effective controls must be implemented. These controls are
generally the recovery or capture of the gases and their incineration
or recovery for additional use. Current issues related to these means
of control are the energy consumption aspects of some of these systems
(i.e., incineration, with net energy losses and the use of scarce
natural gas supplies) and the technical feasibility of the control of
evaporative emissions from the refueling of motor vehicles. (It should
be noted that process losses and transportation or transfer losses can
also be minimized by the use of equipment and proper housekeeping
procedures.)
One of the most significant control requirements currently in
effect for the control of HC from stationary sources are those applicable
to gasoline marketing. Gasoline vapor control regulations require the
control of evaporative hydrocarbons emissions during the storage,
transport, and dispensing of gasoline. Uncontrolled emissions from
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these operations account for about six percent of HC emissions in a
typical AQCR, divided equally among terminal operations, gasoline
delivery to service station storage tanks, and refueling of automobiles.*
Significant emissions reductions and fuel saving are ascribable
to vapor recovery controls. Uncontrolled emissions from vehicle
refueling are approximately equal to th.e hydrocarbons that will be
emitted from the tailpipes of vehicles meeting statutory Federal
standards. Controls on gasoline marketing operations will generally
capture about 11 percent of the needed reductions of hydrocarbons in
an urban area and may, in certain cases, capture as much as 20 percent
of the needed reductions.
The control of evaporative emissions when gasoline is delivered
to storage tanks at service stations is being implemented since
available technology is simple and clearly capable of providing the
requisite control. Likewise, control of terminal operations presents
no technical issues. Issues related to control of evaporative emissions
during refueling of automobiles are the imprecise definition of control
requirements, lack of control equipment that has been adequately demon-
strated in actual use, the absence of test and certification procedures,
and the general risks (technical and financial) to be assumed by service
station owners or operators. Technical issues are being resolved--EPA
* In the EPA regulations, these controls are referred to as Stage I
(for delivery to service station) and Stage II (for refueling
of automobiles).
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has reproposed the Stage II regulations for additional public review
of the issues. It is EPA's policy to require earlier application of
control measures by the larger gasoline marketers since they are
generally better able to assume the risks associated with the instal-
lation of control equipment that is not yet fully proven in actual use.
D. Attainment/Maintenance of Standards in Problem Areas
and New Sources Control
1. Introduction
Practically all major urbanized or industrialized areas of the
country are not meeting one or more of the NAAQS. Although there have
been significant improvements in air quality both in terms of reduc-
tions in ambient concentrations of the pollutants and in terms of the
number of times that the standards are exceeded, it is expected that
the violations of the NAAQS will continue in the future. The principal
issues currently related to air pollution control are those associated
with the attainment of the standards and how to assure overall
reduction in total emissions (and, eventually, attaining NAAQS), while
at the same time allowing for necessary growth of industry, commerce,
and services associated with population increases (e.g., housing,
schools, entertainment facilities, transportation).
The Agency has focused planning for the future maintenance of
standards on selected areas that will most likely require long-term
planning, the Air Quality Maintenance Areas (AQMA). The planning
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that focuses on AQMA, however, will not solve the current attainment
problems. Most growth will occur in areas currently above the
standards—the issue is one related to growth in areas that have yet to
attain the standards, not one of growth in areas that may have to be
concerned with future air pollution problems. Growth must be handled in
the context of attainment of the standards. As far as air pollution
impact is concerned, growth considerations are limited to consideration
of the impact on ambient air quality of changes in emissions from
sources (e.g., new sources, changes in fuel use or industrial processes,
increased production or capacity of existing sources, and increased
motor vehicle use or congestion).
Air quality standards attainment issues often require complex,
long-term solutions. The air quality planning process provides the
tools to address these long-term problems. The solution to such
problems as growth in emissions involves tradeoffs that cannot always be
adequately assessed on a case-by-case basis and must be viewed within
the larger framework of community goals. The support of the community
is necessary to implement complex control strategies. Many controls
require a long lead time for development and implementation. All of
this requires a systematic planning process.
EPA's policy is to address long-term problems, or plan revisions
that may have wide-ranging effects on a community (be they related to
attainment or maintenance), through the process specified in regulations
stating the criteria for the revision of SIPs for the maintenance of
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standards. Any required plan revision (including revisions for
attainment) can be developed using this process.
EPA's aim is the development of an air quality management process
which would more explicitly establish the relationship among all air
quality related requirements. This would be aimed at making trade-offs
at the State and local levels, with citizen participation, among the
various means of achieving the standards. EPA has established a flexible
process for SIP revision so that State and community participation is
assured and to permit the integration of all other planning requirements,
such as 208 area-wide waste treatment management, coastal zone management,
and transportation planning.
2. Development of a Comprehensive Planning and
Decision-Making Process
For areas that have attainment problems, SIP revisions are generally
required,and difficult choices as to new sources have to be made. For
areas that have no significant attainment problems, actions will have
to be taken to avoid future emission increases that would violate
standards. After existing sources have reduced their emissions to the
lowest practical level, further air pollution control can only be
accomplished by implementing rational planning procedures for management
of all new sources of air pollution. This will require extensive
cooperation among the air pollution control community--regional, state,
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and local planning agencies; state and local governments; and the
general public—in order to ensure that future growth plans include
appropriate air quality considerations.
In addition, it should be noted that case-by-case review of new
sources as to air quality impact usually cannot adequately provide for
maintenance of the standards—such reviews alone would tend to ignore
the cumulative impact on air quality of the sources which may be
individually approved,and would not provide for consideration of the
small individual (but, in the aggregate, significant) contribution of
the types of sources that would not be subject to individual review.
Furthermore, a source-by-source review procedure allocates the air
resource on a first-come, first-served basis. For example, the first
source to receive approval may preclude the later approval of all other
sources in the future since the first source may have emissions suffi-
cient to approach the NAAQS in a way that would preclude approval for
any additional sources. A more rational allocation of the air resource
requires more than a source-by-source decision making process.
The nature and magnitude of the restrictions necessary to implement
the provisions of the Act requiring maintenance of standards will vary
with the nature of the specific issue addressed, but determination of
the nature of land use and an assessment of the air pollution impact
of a variety of types of human activity are required. The maintenance
of standards on a regional basis is to be achieved by the development
and implementation of air quality maintenance plans for specific air
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quality maintenance areas (AQMAs) as a minimum. Plans must be developed
for other areas with identified maintenance problems as well.*
The planning process requires a preliminary analysis of work that
may be required to be carried out for plan development and, on the basis
of this preliminary analysis, an agreement between states and EPA regional
offices as to the timing of plan revisions. Issues that States and
localities will have to resolve during the planning for attainment and
maintenance of standards are related to (1) the development and implementation
of a planning process that will lead to the identification and incorporation
of all relevant factors affecting ambient air quality, and (2) the
extent to which emission reductions can be adopted and implemented once
identified. It is clear that a comprehensive air quality plan should
incorporate consideration of all social and economic aspects of the
affected areas. Rational control choices have to be made by the affected
communities. It is EPA's policy to assure as widespread as possible
participation in this decision-making process.
The success of air quality planning depends not only on the ability
to control emissions but also on the ability to guide development in
ways that will minimize the deterioration in specific areas and the
expected long-term growth in emissions. Location decisions for
* An "Air Quality Maintenance Area" is a sub-regional geographic area
in which the maintenance of NAAQS is deemed to warrant special attention.
When an AQMA is established, one or more pollutants are designated as
having the potential of being in future violation of NAAQS. A
regional-scale analysis of such potential violations is then carried out.
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major pollution sources such as power plants and industries must be
checked carefully for their air quality effects; existing regulations
are aimed at doing this. More difficult to take into account, however,
are decisions on such matters as housing, sewer and water systems, and
so on. Thus, to be effective in the long run, air quality planning
must be a factor in decisions on land use, resource development, trans-
portation, housing, and commercial and industrial development.
The Metropolitan Planning Organizations (or similar organizations),
acting in coordination with air pollution control agencies, should have
the principal responsibility for developing the transportation measures
needed to achieve the ambient air quality standards. This activity
should take place as part of the normal urban transoortation planning
process and should be oriented toward developing transnortation plans
and programs that are consistent with air quality requirements and other
community objectives. Ideally, the transportation plans and programs
developed through the urban transportation planning process should be
adequate for inclusion in SIP's with no other transportation control
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measures required.*
3. EPA's Formal Planning Requirements
Regulations pertaining to the analysis and development of plans
for Air Quality Maintenance Areas (AQMA's) were promulgated on May 3, 1976.**
The regulations specify the procedures to be used in estimating future
air quality concentrations and for developing any new control strategies
necessary to ensure the maintenance of the national ambient air quality
standards. They specify the approvable form and content of the analysis
* On September 17, 1975, DOT issued the Transportation Improvement
Program regulations which govern the planning and programming of
Federally sponsored urban transportation improvements (40 FR 42979).
The most significant air pollution control aspects of the DOT regula-
tion are the requirements for the preparation of a Transportation
System Management (TSM) plan and a-short-range Transportation
Improvement Program (TIP). The TSM plan is oriented toward making
efficient use of existing transportation resources and providing
for the movement of people in an efficient manner. It involves
traffic engineering, public transportation, regulatory , pricing,
management, and operational improvements to the existing urban
transportation system,not including new transportation facilities
or major changes in existing facilities. Examples of TSM measures
are traffic flow improvements, preferential treatment of buses,
parking management, pricing policies, and auto-free zones. The
TIP is a staged 3- to 5-year program of transportation improvement
projects recommended for advancement during the program period.
The TIP identifies priorities and includes estimates of program
costs and revenues for the program period. In effect, the TIP is
a plan for transportation improvements over a 3- to 5-year period.
The TSM plan and TIP are developed by the Metropolitan Planning
Organization (MPO) in each urban area. The MPO provides a forum
for cooperative decision-making by principal elected officials of
general purpose local governments.
** Federal Register, May 3, 1976, pages 18382 to 18391. These regula-
tions modify key parts of Part 51 regulations and add a Subpart D,
Maintenance of National Standards, to Part 51. Part 51 regulations
set forth EPA's criteria for development and approval of SIPs.
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and plan revisions required in AOMAs and other areas identified by
EPA. Although the procedures are aimed at the planning for maintenance
of standards, they are generally applicable to air quality planning.
At the Regional Administrator's discretion, these procedures can be
applied to other areas in need of implementation plan revisions for
attainment and maintenance.
Briefly, the process for developing a maintenance plan consists
of the following tasks: Projecting emissions into the future;
allocating emissions according to estimated projections of location of
sources; calculating air quality resulting from the future emission
pattern; developing a control strategy needed to maintain the national
ambient air quality standards; and adopting regulations to make the
control strategy enforceable.
The regulations leave in the hands of the States the choice of
measures that are needed to maintain the national air duality standards.
EPA's policy is to be flexible with regard to these plans to allow
maximum consideration of varying local conditions. EPA will call for
plan revisions for maintenance whenever their need is determined on a
case-by-case basis. The time period for which maintenance is to be
insured will also vary from area to area. The date by which such plan
revisions are to be submitted will be determined by EPA in consulta-
tion with States. EPA requires a reanalysis of all areas of all States
at least every five years to determine if any areas are in need of
plan revisions.
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The regulations require States to analyze air nualit.y for 20
years. EPA Regional Administrators, however, have the authority to
shorten the analysis period to no less than 10 years. Where long-ranee
data are unreliable, the Regional Administrators can set a shorter
period (at least three years) for the period over which a plan must
demonstrate maintenance of the NAAOS. The analysis beyond 10 years
is designed to foster awareness of existing State land use and trans-
portation plans that extend beyond 10 years, so that the State can
consider the air quality implications of these other plans. Additionally,
the regulations limit EPA's discretion on actinci on State reauests for
modification: The Administrator must act within 45 days of receipt of
the request, or the request will be deemed automatically approved.
4. New Stationary Sources'Review and Control
a. Introduction
A key element in the control of increases in emissions is reviewing
the air pollution impact of new sources (or modifications of existing
sources) prior to the time a commitment to construct or modify is made.
Conceptually, the aim of new source review is to assure that the proposed
source's impact on air quality does not interfere with the attainment
or maintenance of the NAAOS or other ambient air Quality goal (e.g.,
the prevention of significant deterioration of air quality).* New
* Of course, new sources also have to comply with all other emission
limitations, such as New Source Performance Standards or hazardous
pollutant emission standards. New source reviews can also be
carried out to verify compliance with these emission limitations.
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sources have basically two options under a new source review process.
They can either meet emissions limitations that are consistent with the
air quality goals that are applicable to the proposed location of the
source (sometimes derived during the review process), or they can select
an alternative site where air quality is not a problem or control needs
are less. In order to consider decisions on new sources in their proper
social and economic as well as air quality context, EPA's policy.is one
of encouraging the development of appropriate decision-making processes
at the State and local level. The policies for developing comprehensive
plans were discussed above. Policy decisions on new sources in nonattainment
areas are discussed below.
State Implementation Plans are required by 40 CFR 51.18 to contain
procedures for preconstruction review of new sources to assure that such
sources will not cause violations of the ambient standards or any
applicable control strategy. Most SIPs have approved State procedures
(and State responsibility for action), while a few have provisions
promulgated by EPA (and EPA is responsible for carrying out new source
review).* Specific decisions on individual sources may require much
technical analysis and the commitment of significant resources to comply
with emission limitations.
* New source reviews are generally administered through a permit system.
Under such systems, a source applies for permission to construct
or operate; the permit application generally includes data on the
facility, its air quality impact, etc. The procedural outcome of a
review, then, is the approval or disapproval of permission to operate
or construct the facility.
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In general, the first determination that must be made for a new
source review is whether or not the source is covered by an applicable
emission requirement and, if so, if it meets the limitation of that
requirement. In those cases where the proposed new source will not meet
the applicable emission requirements, a permit to construct must be
denied.
If the appropriate emission limitations will be met, an air quality
impact analysis is required for major sources. If the air quality
impact analysis indicates that the source's emissions will not lead to
the violation of the NAAQS or contribute to it, a permit to construct is
issued. However, this presents a difficult situation for those areas of
the country where NAAQS are currently exceeded. Arguably, no new source
should be permitted in these areas since any increase in emissions could
aggravate air quality problems.
b. New Sources in Nonattainment Areas--
"Emissions Offset" 'Policy
It is EPA's policy to allow the location of major new and expanded
sources in areas where NAAQS are currently exceeded only to the extent
that the resulting emissions do not exacerbate current violations of the
primary standards and do not interfere with making reasonable progress
toward the timely attainment of the standards.
EPA's policy, based on its conclusions as to the most flexible yet
rational interpretation of the Clean Air Act's requirements, has been
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documented In an Interpretative Ruling.* This ruling addresses the
issue of whether and to what extent national air quality standards
established under the Clean Air Act may restrict or prohibit growth of
major new or expanded stationary air pollution sources. The ruling
provides in general that a major new source may locate in an area with
air quality worse than a national standard only if stringent conditions
can be met. These conditions are designed to insure that the new
source's emissions will be controlled to the greatest degree possible;
that more than equivalent offsetting emission reductions ("emission
offsets") will be obtained from existing sources; and that there will be
progress toward achievement of the standards. The reader is referred to
the ruling itself for its specific provisions. While the ruling is
effective now, EPA is actively soliciting public comment on the ruling's
basic policies and detailed provisions. (EPA also intends to modify the
Part 51 regulations, specifying SIP requirements, in keeping with this
ruling.)
c. Prevention of Significant Deterioration
of Air Quality
The Clean Air Act requires the prevention of significant deteriora-
tion of air quality in currently clean areas. EPA has promulgated
regulations which implement this requirement of the Act. (Final regulations
were promulgated on December 5, 1974.) EPA's requirements are implemented
* This ruling was published in the December 21, 1976 Federal Register,
pages 55524 to 55528. This ruling interprets the way in which the
requirements of 40 CFR 51.18 are to be implemented.
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through a new source review procedure. In developing its implementing
regulations, EPA had to decide what degree of air quality deterioration
would be considered "significant" since there has been no specific
judicial or Congressional guidance. In areas having very clean air, it
was not possible to set standards based on any measurements of damage to
the public health and welfare. On the other hand, it was the intent of
the law to prevent air quality everywhere from being uniformly degraded
through a "leveling out" of the Nation's air pollution. The EPA regulations
seek to define "significant" in a reasonable way that will allow for
protection of clean areas and for national economic growth. Any growth
that occurs will be with the application of best available control
technology.
For purpose of implementation, the country will ultimately be
divided into three types of areas:
Class I—regions where practically any air quality deterioration
would be considered significant.
Class II--regions where deterioration in air quality that would
normally accompany moderate, well-planned growth, would not be con-
sidered significant.
Class Ill—regions where intensive major industrial growth is
desired.
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The benchmarks to be used in judging the impact of new sources on
clean areas are increments of ambient concentrations of total suspended
particulates and sulfur dioxide. The start for assessing source impact
against these increments was January 1, 1975. These increments for
areas are:
Area TSP Qug/m3) S02 (ug/m3)
Classification*
Class I
Class II
Annual
5
10
24 hr.
10
30
Annual
2
15
24 hr.
5
100
3 hr
25
700
Issues related to these regulations concern industrial development
and impacts of development in Class III areas on surrounding Class I or
II areas. EPA believes that normal, orderly growth is possible within
the framework of the regulations. The air pollution limit for a Class
II area, for example, would (under normal circumstances) permit construction
of any of the major source categories listed below. In a Class III
area, an aggregation of major industrial projects may be constructed as
long as air quality standards are not exceeded. (These standards must
be met everywhere even in the absence of these regulations.)
The increments for Class II areas were developed taking into
account the impact that they would have on industrial development. The
Class II increment will permit construction and operation of major,
economically sized industrial facilities. The increments do place
constraints on control technology requirements and siting considerations.
* Class III areas would be allowed to reach the levels of the most
restrictive NAAQS.
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None of the limitations in spacing of plants would lead to a general
prohibition on industrial growth.
EPA has initially designated all areas of the country as Class II.
Under the EPA regulations, the States (including sovereign Indian
governing bodies) may request redesignation of an area to Class I or
Class III. (Managers of Federal land, however, may request designation
only from Class II to Class I.) The redesignation of an area may be
necessary to achieve the social, economic or environmental objectives of
its population or of the Nation as a whole. The regulations give
the primary decision-making responsibility to the States to help them
achieve their various objectives. The area reclassification process is
expected to be similar to the process for public participation for
development of maintenance of NAAQS plans.
Apart from the reclassification process, which is a planning and
decision-making process, compliance with the regulations is strictly a
new source review procedure; new sources can be approved until the point
that the air quality increments applicable to an area are exhausted. In
case that the air quality increment is exhausted, an area can be
reclassified if additional growth in emissions is desired. However, at
no time can the NAAQS be exceeded.
The prevention of significant deterioration regulations require the
application of BACT for major source categories as a condition for the
permit to construct: Fossil-fuel steam electric plants of more than
1,000 million B.T.U. per hour heat input; coal cleaning plants; kraft
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pulp mills; portland cement plants; primary zinc smelters; iron and
steel mills; primary aluminum ore reduction plants; primary copper
smelters; municipal incinerators capable of burning more than 250 tons
of refuse per day; sulfuric acid plants; petroleum refineries; lime
plants; phosphate rock processing plants; by-product coke oven batteries;
sulfur recovery plants; carbon black plants; primary lead smelters; fuel
conversion plants; and ferroalloy production facilities.
EPA believes that decisions about development of affected areas
should not be based only on environmental factors. For this reason, as
long as proper procedures are followed and decisions are not arbitrary
or capricious in light of the relevant factors, State and local decisions
about whether to reclassify an area to Class I (minor development) or
Class III (whatever development the air quality standards will allow)
will not be questioned.
d. Federal New Source Performance Standards
(NSPS) for Criteria Pollutants
The setting of performance standards for new sources is authorized
under Section 111 of the Act. NSPS prevent or reduce the magnitude of
increases in emissions from stationary sources resulting from expanded
industrial activity and/or new or modified sources, provide a mechanism
by which the Federal Government determines (and makes available to
States) the feasibility of control for emerging industries (i.e.,
defines BACT), and provide the only means for control of stationary
sources of selected pollutants for which a NAAQS or hazardous pollutant
designation is not applicable.
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The setting of NSPS must (as required by the Act) take into
consideration the costs of achieving the emission levels to be required.
Therefore, issues related to the NSPS largely revolve around the standard-
setting process rather than source compliance with emission limitations.
In general, the courts have upheld the NSPS challenged to date.
As indicated earlier, the prevention of air pollution problems due
to future growth in hydrocarbon emissions and nitrogen oxide emissions
is highly dependent on the controls that are to be applied to new
sources of these pollutants. The problem related to N02 is currently of
low significance; only five AQCRs are classified as requiring emission
controls. However, there is a clear danger that increases in emissions
due to expanded economic activity will lead to widespread NAAQS violations
by the 1980s unless new sources are controlled. The current control
philosophy for mobile sources emissions stresses the need for stringent
NOX controls in the 1980s; a complementary program for the control of
stationary sources is required. The setting of standards for new
sources now is preferable to the setting of control requirements under
the SIP process later in order to prevent the possibility of widespread
NAAQS violations in the future. The need to prevent increases in
emissions of hydrocarbons for new stationary sources is similar to the
need for such control of NOX. NSPS to be set in the future concentrate
on sources of these pollutants. The sources covered by NSPS and sources in the
process of, or under consideration 'for, being covered are listed in Appendix B.
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Procedural requirements applicable to sources covered by NSPS are
minimal. In brief, compliance with emissions limitations is required as
well as compliance with certain self-monitoring requirements.
State* or EPA enforcement of NSPS entails maintaining surveillance over
sources covered, preconstruction review at the request of the source
owner or operator, observation of source tests and evaluation of
results, and enforcement proceedings against sources found not to be in
compliance. EPA involvement with delegated NSPS entails the monitoring
and evaluation of State enforcement progress, making determinations on
how the standards are to be applied, the provision of technical advice
and support, and, if needed, direct enforcement action.
* EPA may delegate to States the enforcement of NSPS. It is the
policy to delegate the authority to enforce these standards.to. the
States whenever States meet requisite criteria, i.e., the State
submits a plan for enforcement of the NSPS and EPA approves it.
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III. The Control of Other Than Criteria Pollutants
A. Introduction
The Clean Air Act provides various mechanisms for the control of
pollutants depending on such factors as their effects, the types of
sources that emit them, ^and the best means of controlling them. The
preceding discussion dealt with those pollutants for which criteria have
been issued and NAAQS set. This part of the discussion outlines the
controls in effect or projected for pollutants not controlled by NAAQS.
For pollutants emitted from less widespread sources or a limited class
of sources, or having limited effects, possible control mechanisms are
provided by sections 112 (hazardous pollutants), 111(d) (control of air
pollutants not covered by NAAQS and not determined to be hazardous
under section 112), and section 211 (regulation of fuels, for control of
pollutants which are emitted as a result of having been incorporated
into motor vehicle fuels).*
Pollutants with significant localized effects are of concern to
EPA. It is EPA's policy to proceed as expeditiously as possible with
control actions, under the most appropriate authorities of the Act,
* Pollutants controlled under these authorities are generally known
as "noncriteria" pollutants, i.e., not covered by criteria documents
issued under section 108 of the Act. Only TSP, S02, CO, Ox, ^2>
and HC are covered by criteria documents. There are additional
authorities related to non-criteria pollutants under section 119(d)
(3) (B). These authorities are limited to prohibition orders
issued by FEA for the use of coal and are of limited applicability.
They are not discussed here.
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for the control of those pollutants which present a significant risk to
health or welfare and those pollutants for which Federal action is the most
effective means of control. (It should be noted that there are cases
for which State action is appropriate in the absence of Federal action;
States are encouraged to utilize their authorities for the control of
air pollutants whenever warranted.) For those pollutants for which
Federal control action is appropriate, the philosophy of the Act requires
primary Federal action for the control of sources of hazardous air
pollutants, with provisions for delegation of enforcement responsibilities
to the States. Furthermore, the Act requires primary State action for
the control of existing sources of the pollutants controlled under
section 111 *(based on EPA guidance) with a secondary Federal role
thereafter, i.e., EPA action is required only upon State failure to act.
If a pollutant is of such a hazardous nature that immediate abatement
of emissions is desired from both existing and new facilities (i.e., the
Administrator of EPA finds that there .is no applicable ambient air
quality standard and the pollutant, in the judgement of the Administrator,
causes or contributes to an increase in mortality or an increase
in serious irreversible, or incapacitating reversible, illness) then
direct Federal control under section 112 is indicated. Under Section
112, all new sources are subject to control immediately upon promulgation
of standards by EPA,and all existing sources are to be in compliance
within 90 days of the EPA action unless granted waivers.
But not controlled by NAAQS or NESHAP,
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Where a non-criteria pollutant is not hazardous (as that term is
defined by section 112), i.e., it has a lower potential for impacting
public health, then section 111 would be the mechanism for action.
Pollutants emitted by only specific sources may be controlled under the
provisions of section 111 by the setting of performance standards for
new sources; if such a standard is set for a pollutant not covered by
criteria and not determined to be hazardous under section 112, then
existing sources of the pollutant are to be controlled by the States
(or, in the absence of State action, by EPA) subsequent to the issuance
of NSPS by EPA. Under section lll(d), States prepare plans for the
control of existing sources under a process similar to the State :
Implementation Plans.
B. National Emission Standards for Hazardous Air Pollutants
Section 112 of the Clean Air Act requires the Administrator to
establish national emission standards for hazardous air pollutants. A
list of such substances (identifying asbestos,beryl 1iurn, and mercury as
hazardous pollutants) was published in the Federal Register on
March 31, 1971. In accordance with waiting periods and public hearing
requirements of the Act, proposed regulations for their control were
published in the Federal Register on December 7, 1971. Final regulations
were promulgated April 6, 1973. Clarifying regulations were promulgated
May 3, 1974, October 14, 1975, and March 2, 1977. Sources and pollutants
covered by the NESHAP are listed in Table I.* EPA also has promulgated
* The regulations are contained under 40 CFR 61; a detailed explanation
of the Agency's positions on the control of asbestos, mercury, and
beryllium may be found in the April 6, 1973, Federal Register,
38 FR 8820, et. seg.
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regulations to control emissions of vinyl chloride from facilities that
manufacture both vinyl chloride monomer and polyvinyl chloride.* At
this time benzene and organic compounds emitted from coke ovens are
scheduled to be added to the list of hazardous air pollutants. In
addition, investigations are currently underway for several pollutants
to determine the optimum control option for each, which may include
Section 112.
EPA Regional Offices are maintaining surveillance over sources,
observing source tests and evaluating results, and carrying out
enforcement proceedings against sources found not to be in compliance.
These activities may be carried out by States when they are delegated
enforcement authority, i.e., when they submit an acceptable plan for
carrying out such actions. It is the Agency's policy to delegate
enforcement authority to States; they are encouraged to develop programs
for enforcing these regulations.
* The regulations for vinyl chloride were published in the October 21,
1976, Federal Register (4 FR 46560 et. seq.).
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Table I - Summary of NESHAP
Pollutant
Asbestos
Applicable to:
10/14/75
Beryllium
4/6/73
Mercury
Vinyl Chloride
4/6/73
10/14/75
10/21/76
Asbestos mills
Roadway surfacing (asbestos
tailings)
Manufacturing of products
containing asbestos (textiles,
cement, fireproofing and
insulating materials,
friction products, paper,
millboard, felt, floor tile,
paints, coatings, caulks,
adhesives, and sealants)
Chlor-alkali manufacture
Demoli ti on
Manufacture of shotgun shells
and asphalt concrete
Fabricating
Waste disposal
Extraction plants
Ceramic plants
Foundries
Incinerators
Propellant plants
Machining operations
Rocket motor firing
Ore processing
Chlor-alkali manufacture
Sludge dryers or incinerators
Ethylene dichloride manufacture
by reaction of oxygen and
hydrogen chloride with
ethylene.
Vinyl chloride manufacture
Polymer manufacture via vinyl
chloride
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C. Control of Selected Pollutants
Section lll(d) of the Act provides a mechanism for the control
of pollutants not covered by criteria (Section 108) or National Emission
Standards for Hazardous Air Pollutants (Section 112). The Act provides
that States set up a system for the control of existing sources of the
non-criteria pollutants for which EPA sets NSPS. Sulfuric acid mist
from sulfuric acid plants and fluorides from primary aluminum reduction
and phosphate fertilizer plants are currently covered by this requirement.
The criteria to be used for developing State control programs
require a separate rule-making action on the part of EPA. These
separate State guidelines will specify the levels of emissions control
that are achievable for existing sources and will provide guidance
as to economic factors to be considered by the States in the development
of control plans applicable to existing sources. States are to submit
their control plans nine months after EPA promulgation of the guidance
document.
D. Lead
EPA has chosen to control lead as a fuel additive since this is
the most effective means of reducing environmental exposures: 90
percent of lead emissions to the atmosphere come from motor vehicles.
The reduction of lead in gasoline is required under regulations issued
under the authorities of section 211 of the Clean Air Act. These
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regulations are currently effective, EPA's position having prevailed
after two years of litigation initiated by fuel additive manufacturers.
(Another set of regulations set under Section 211, requiring the
availability of lead-free gasoline for use in vehicles equipped with
catalysts, is also in effect.)
Another court case has resulted in an order requiring the listing
of lead as one of the air pollutants for which the EPA Administrator
intends to issue criteria and NAAQS. EPA will issue a criteria document
and proposed NAAQS for lead during August 1977.
E. Arsenic
Available ambient air quality data indicate that airborne arsenic
is not a widespread air pollution problem. However, both air quality
data and emission estimates indicate that substantial amounts of arsenic
can be emitted during non-ferrous ore smelting operations. The need
for emission standards is being investigated for the several smelter
sites where a local problem may exist. Other sources of arsenic
emissions do not appear to be a significant problem.
Because the air quality level and estimated emissions of arsenic
around some non-ferrous smelters appear to be significant, regulatory
action on arsenic may be necessary. However, the current data base
is not comprehensive enough to support such action. Studies carried
out by EPA should provide sufficient basis for and background upon
-------
which to make a decision regarding action on arsenic, with the decision
for control action probably to be made in two years. In the interim,
EPA will initiate studies to develop control technology information
to be used in the regulation (if warranted) of arsenic emissions from
smelters.
F. High Volume Industrial Organic Chemicals (HVIOC)
Increasingly, the industry viewed as a significant source of toxic
and carcinogenic agents is that of the rapidly expanding manufacture of
synthetic organic chemicals. EPA is aiming at widespread control of
many types of organic pollutants through the use of new source performance
standards (NSPS) under Section 111 of the Act. Section 111 can be used
to cover most of the organic compounds which have potential adverse
health effects in addition to those organics that contribute to the
oxidant problem, i.e., setting NSPS for these sources will result in
control for both criteria and non-criteria pollutant emissions.
Significant emission reduction through this mechanism will require many
years, but the growth of the chemical industry is rapid, replacement
of obsolete processes is common, and new source standards represent a
good start for control of emissions.
There are approximately 11,000 commercial organics currently
marketed with hundreds of new compounds synthesized each year. An
initial group of these chemicals has been selected for assessment as
potential toxic atmospheric pollutants. (Table II lists these
- 92 -
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pollutants.) One of the 22, benzene, has been identified as a
pollutant for which a more detailed assessment should be conducted
in the near future. It is expected that such an assessment will be
completed by the end of FY 1977. An additional group of substances,
numbering about 700, is under review.
As a group, these materials are of concern as toxic agents,
contributors to oxidant formation, and, some species (freons), as a
threat to upper atmospheric stability. Wide ranging information
gathering and engineering activities are underway in each of these areas.
Emission standards are anticipated for several industries where emissions
contribute significantly to oxidant formation. Although EPA has made
studies to assess the impact of controlling freons, at this time
evidence does not warrant control for- these chemicals under the Clean
Air Act.
Recent examples of chemicals causing concern from an air pollution
standpoint include vinyl chloride and nitrosamines. Most of the members
of the class of nitrosamine compounds are documented carcinogens in
animals. Nitrosamine levels in the atmosphere have been found to be
the result of direct emissions from a rocket fuel manufacturing facility
and amine producing plants. They may also be produced in the atmos-
phere or in the body by reactions of nitrogen oxides and certain amine
precursors. At present and over the near-term, efforts will be focused
on the identification of sources of nitrosamines, their precursors,
- 93 -
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Table II - High Volume Industrial Organic Chemicals
Being Assessed for Air Pollution Potential
cresols
toluene
ethylene dibromide
trichloroethylene
perchloroethylene
vinylidene chloride
"carbon tetrachloride
nitrobenzene
phthalic anhydride
Maleic anhydride
dimethyl terephthalate
acetylene
acrylonitrile
acetone
cyclohexanone
formaldehyde
methyl methacrylate
oxylene (1,3 dimethyl benzene)
methyl alcohol
adipic acid
ethylene dichloride
benzene
- 94 -
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and techniques for control. Regulatory action for vinyl chloride was
completed in October 1976.
Virtually all organic chemicals also are photochemically reactive,
with some compounds reacting quickly to form oxidants while others react
more slowly, thus causing oxidant problems many miles away. Many
organic chemicals have the potential for reacting with other chemicals
in the atmosphere or deteriorating to produce other potentially
dangerous compounds. There is evidence that the combination of a number
of these compounds in the atmosphere may cause synergistic effects or
act as co-carcinogens.
In the short term, use of NSPS minimizes emission increases of
pollutants which may already be a problem but have not been recognized,
or for which documentation is not sufficient to initiate other
regulatory options. In the longer term, the use of NSPS should result
in substantial decreases in organic chemical emissions due to the rapid
equipment replacement rate typical of the chemical industry.
G. Polycyclic Organic Matter
Ambient air concentrations of POM have been decreasing since 1966
as a result of control of smoke and general particulates.
The remaining significant source, coke ovens, may be controlled by
Federal regulation under section 112 of the Act.
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H. Polychlorinated Biphenyls (PCBs)
"PCBs are primarily a human health problem due to their bioaccumulation
in fish. Also of significance are the potential effects of PCBs on
aquatic food chains. The significance of the air route of direct human
exposure has not yet been assessed. These problems associated with PCBs
may necessitate the control of selected sources of air emissions (e.g.,
transformer and/or capacitor plants) if current monitoring work confirms
these plants as significant sources of PCBs. Such action may be
required even with the stringent control of PCBs required by the Toxic
Substances Control Act.
Municipal incinerators are also being investigated to determine
their impact as sources of PCBs. Should these investigations confirm
that they are significant sources, the upgrading of control systems for
PCBs control will be quite costly and probably justifiable only on the
basis of the control of a number of toxic organics, as opposed to
control of PCBs alone. These control actions are also dependent on the
success or failure of efforts to eliminate PCBs by substitution.
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I. Cadmium
EPA is concerned over environmental loading of cadmium via the
air route; however, even under the most pessimistic assumptions, it
cannot be concluded that collective environmental exposure to all
routes of body entry present a human health problem. The primary route
of entry of cadmium to the body is through food ingestion. A secondary
source is from inhalation of cigarette smoke. Inhalation of ambient
air represents the least important route of entry to the body and it
would require air concentrations five times those found under worst
case conditions to be of concern to human health.
J. Manganese
Manganese does not present a human or environmental health threat
at existing ambient levels and warrants no national regulatory program.
However, EPA will reassess this conclusion if manganese becomes widely
used as a fuel additive.
K. Other Trace Metals
Screening and assessment of other trace metals (chromium, nickel,
selenium, zinc, copper, platinum, vanadium, iron, barium) is underway
both through the National Academy of Sciences and within EPA. There
is no evidence to date that would require control action for any of
these materials at this time.
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L. Odors
Odors are considered primarily a problem that should be handled
by state and local authorities. With the exception of Federal emission
standards for total reduced sulfur from pulp mills and sulfur recovery
plants, no national regulatory program for odors is being pursued.
- 98 -
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APPENDIX A
a/
1. National Ambient Air Quality Standards-
Pollutant
Particulate
matter-7
Sulfur
Dioxide
Carbon
Monoxide
Photochemical
oxidants-
Hydrocarbons-
(nonmethane)
Nitrogen ,
Dioxide^
Averaging
Time
Annual (Geo-
metric mean)
24-hour
Annual (Arith-
metic mean)
24-hour
3-hour
8-hour
1-hour
1-hour
3-hour
(6 to 9 a.m.)
Annual (Arith-
metic mean)
n • b/
Primary-'
Standards
75 ug/m3
260 ug/m3
80 ug/m3
(0.03 ppm)
365 ug/mj
(0.14 ppm)
10 mg/m
(9 ppm)3
40 mg/m
(35 ppm)
160 ug/nr
(0.08 ppm)
160 ug/m
(0.24 ppm)
•100 ug/m
(0.05 ppm)
c/
Secondary-
Standards
60 yg/m
150 ug/m
1300
(0.5 ppm)
Same as
primary
Same as
primary
Same as
primary
Same as
primary
a/ All standards (other than annual standards) are specified as not to
be exceeded more than once per year. The measurement methods are
also specified as Federal Reference Methods. The air quality
standards and a description of the reference methods were published
on April 30, 1971 in 42 CFR 210, recodified to 40 CFR 50 on
November 25, 1972.
b/ Set for the protection of health.
c_/ Set for the protection of welfare, which, in the words of the Act
"includes, but is not limited to, effects on soils, water, crops,
vegetation, manmade materials, animals, wildlife, weather, visibility,
and climate, damage to and deterioration of property, and hazards
to transportation, as well as effects on economic values and on
personal comfort and well being." (Section 302 (b).)
d_/ The secondary annual standard (60 ug/m ) is a guide to be used in
assessing implementation plans to achieve the 24-hour secondary standard.
e/ Expressed as ozone by the Federal Reference Method.
f_/ This NAAQS is for use as a guide in devising implementation plans
to achieve oxidant standards.
g_/ No Federal Reference Method currently in effect.
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2. Sources of Information on Health Effects
of Air Pollutants
The following pubications provide information on the effects of
air pollutants:
1. Air Quality Criteria for Particulate Matter. U. S. Department of
of Health, Education, and Welfare, Public Health Service
Environmental Health Service, National Air Pollution Control
Administration, Washington, D. C., January 1969, Publication
No. AP-49.
2. Air Quality Criteria for Sulfur Oxides, U. S. Department of Health,
Education, and Welfare, Public Health Service, Environmental Health
Service, National Air Pollution Control Administration, Washington,
D. C., Publication No. AP-50.
3. Effects of Sulfur Oxides in the Atmosphere on Vegetation; Revised
Chapter 5 for Air Quality Criteria for Sulfur Oxides, National
Environmental Research Center, Office of Research and Development,
U. S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, September 1973, EPA-R3-73-030.
4. Air Quality Criteria for Carbon Monoxide, U. S. Department of
Health, Education, and Welfare, Public Health Service, Environmental
Health Service, National Air Pollution Control Administration,
Washington, D. C., March 1970, Publication No. AP-62.
5. Air Quality Criteria for Carbon Monoxide, NATO Committee on the
Challenges of Modern Society, Air Pollution Technical Information
Center, Office of Air Programs, Environmental Protection Agency,
Research Triangle Park, North Carolina 27711, N. 10.
6. Air Quality Criteria for Photochemical Oxidants, U. S. Department
of Health, Education, and Welfare, Public Health Service,
Environmental Health Service, National Air Pollution Control
Administration, Washington, D. C., March 1970, Publication No. AP-63.
7. Air Quality Criteria for Hydrocarbons, U. S. Department of
Health, Education, and Welfare, Public Health Service,
Environmental Health Service, National Air Pollution Control
Administration, Washington, D. C., March 1970, Publication No. AP-64.
A-2
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3. Air Quality Criteria for Photochemical Oxidants and Related
Hydrocarbons, Committee on the Challenges of Modern Society,
North Atlantic Treaty Organization, Air Pollution Technical
Information Center, Office of Air and Water Programs, Environmental
Protection Agency, Research Triangle Park, North Carolina 27711,
U.S.A., N. 29.
9. Air Quality Criteria for Nitrogen Oxides, Environmental Protection
Agency, Air Pollution Control Office, Washington, D. C., January
1971, Publication No. AP-84.
10. Air Quality Criteria for Nitrogen Oxides, NATO Committee on the
Challenges of Modern Society, Air Pollution Technical Information
Center, Office of Air Programs, Environmental Protection Agency,
Research Triangle Park, North Carolina 27711, N. 15.
11. Automotive Air Pollution and Human Health: A Seminar in Hartford,
Connecticut, October 1975. U. S. Environmental Protection Agency,
Air & Hazardous Materia-ls Division, Region I, Boston, Massachusetts,
October 1975.
12. The Health Implications of Photochemical Oxidant Air Pollution
to Ypur Community, U. S. Environmental Protection Agency,
August 1976.
A-3
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APPENDIX B
Summary of New Source Performance Standards
Date
Effective*
August 17,
1971
August 17,
1971
August 17,
1971
August 17,
1971
August 17,
1971
June 11,
1973
June 11,
1973
June 11,
1973
Sources Covered
Pollutants
Controlled
Fossil fuel-fired S02, NOX &
steam generators particulate
matter
Incinerators
Portland cement
plants
Nitric acid
plants
Sulfuric acid
plants
Asphalt concrete
plants
Petroleum
refineries
Storage vessels
for petroleum
liquids
Particulate
matter
Particulate
matter
NO,
S02, acid
mist
Particulates
carbon monox-
ide and hydro-
gen sulfide
Affected Facility
Each fossil fuel-fired steam
generating unit of more than
250 million B.T.U. per hour
heat input.
Each incinerator of more
than 50 tons per day
charging rate.
Kiln, clinker cooler, raw
mill system, finish mill
system, raw mill dryer, raw
material storage, clinker
storage, finished product
conveyor transfer points,
bagging and bulk loading and
unloading systems.
Each nitric acid production
unit.
Each sulfuric acid
production unit.
Particulates Process equipment.
Catalyst regenerators
fluid catalytic cracking
units, process gas burners
Hydrocarbons Entire facility
The effective date for NSPS is that of proposal in the Federal
Register. All affected sources that are being or have been modified
or construction started as of this date must comply with the standards.
Definitions of applicability of standards are contained in 40 CFR 60.
-------
NSPS
(Continued)
Date
Effective
June 11 ,
1973
June 11 ,
1973
Sources Covered
Secondary lead
smelters
Secondary brass
and bronze and
Pollutants
Controlled
Particulates
Particulates
Affected
Furnaces
Furnaces
Facility
June 11,
1973
June 11,
1973
October 21,
1974
October 22,
1974
October 23,
1974
October 21,
1974
October 24,
1974
October 16,
1974
ingot production
plants
Iron and steel
plants
Particulates
Sewage treatment Particulates
plants
Electric arc
furnaces
Particulates
Phosphate fertil- Fluorides
izer plants
Primary aluminum Fluorides
plants
Ferroalloy
production
Particulates
and CO
Coal preparation Particulates
plants
Non-ferrous Particulates,
smelters: copper, S02
zinc, and lead
Basic oxygen process
furnaces
Sludge incinerators
Electric submerged arc
furnaces and dust
handling equipment
B-2
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Currently in process for NSPS-setting are the following:
Source Category Pollutant
Lignite steam generators
Grain terminals
Kraft pulp mills
Coal/refuse boilers
Coke ovens - charging
Sulfur recovery at refineries
Gas turbines
Chior-alkali
Crushed stone plants
Degreasing
Phosphate rock preparation
Carbon black
Iron & steel sintering
Gasification of fossil fuel
Stationary internal combustion engines
Lime plants
Coke ovens-pushing
Grey iron-electric arc furnaces
Asphalt roofing
Sulfur recovery at oil fields
NO , Part.
Particulates
Part., odors*
Particulates
Particulates
SOX and Particulates
SOX NOX, HC, Part.
Mercury
Particulates
HC
Particulates
HC, Part. CO
Particulates, SOX
Particulates, SOX
NOX, HC, Particulates
Particulates
Particulates, HC
Particulates
Particulates, HC
SOv
Under consideration for action are:
Source Category
Boilers (3 sizes)
Taconite 'beneficiation
Wood waste boilers
Motor vehicle surface coating
Coal liguefaction
Ethylene oxide manufacturing
Explosives
Charcoal manufacture
Farm machinery surface coating
Industrial machinery surface coating
Pollutant
NOY, particulates
HC
Particulates, SO?
HC
NOX, SOX, particulates
HC
HC
HC
TRS, or total reduced sulfur, is to be controlled.
B-3
-------
(Continuation)
Source Category Pollutant
Commercial machinery surface coating HC
Major appliances surface coating HC
Dry cleaning HC
Foundries-steel Particulates
Auto body incineration Particulates, HC
Cast iron boundry (Coke Ovens) Particulates, HC
Coke ovens-pushing operations Particulates, HC
Nylon acetate fibers HC
Industrial/commerical incinerators HC, Particulates
Plywood manufacture HC, Particulates
Shale oil processing $03, HC, TRS
B-4
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APPENDIX C
Determination of Best Available Control
Technology and Reasonably Available Control Technology
A. Best Available Control Technology
BACT is defined in 40CFR §52.01 (f) as follows:
The term "best available control technology," as applied to any
affected facility subject to New Source Performance Standards, means any
emission control device or technique which is capable of limiting
emissions to the levels proposed or promulgated as NSPS. Where no
standards of performance has been proposed or promulgated for a source
or portion thereof, best available control technology is determined on a
case-by-case basis considering the following:
(1) The process, fuels, and raw materials available and to be
employed in the facility involved;
(2) The engineering aspects of the application of various types of
control techniques which have been adequately demonstrated;
(3) Process and fuel changes;
(4) The respective costs of the application of all such control
techniques, process changes, alternative fuels, etc.;
(5) Any applicable State and local emission limitations; and
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(6) Locational and siting considerations.*
This definition is applicable to all EPA regulatory actions related to
SIPs, specifically in relation to the use of tall stacks for new
facilities and the prevention of significant deterioration of air
quality.
B. Reasonably Available Control Technology
1. General
BACT may not always be applicable to sources, especially existing
ones that require retrofitting under SIPs. For these cases, the Agency
requires the application of RACT. At the present time, the concept
of RACT is important in regard to:
Determining whether existing SIP regulations are
"adequate" or not.
. Determining whether a given overall control strategy represents
the most comprehensive and aggressive control program that is
reasonably practicable. This determination will be important
as states develop and EPA reviews (or promulgates) SIP revisions
in the actions scheduled for the period July 1976 to July 1978.
When all RACT is applied, other measures are required to demon-
strate attainment. If all RACT is not applied by a state, EPA
* 40 CFR 52.01
C-2
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would require the state to do so or will promulgate its
own regulations.
. Determining when SCS or a tall stack may be used to prevent
violations of NAAQS by existing sources.
The concept of RACT was involved in the SIPs developed in late
1971 and early 1972. It served as a basis for determining whether a
State could be granted an 18-month extension of the date when plans to
attain the secondary standards were to be submitted. If control
measures more stringent than those defined as RACT were needed to attain
secondary standards, an extension could be granted. To assist in
creating an understanding of what RACT meant, a series of examples of
emission limitations attainable by various source classes with RACT
was prepared and was incorporated as Appendix B of 40 CFR 51. Appendix B
was also used as one input in determining whether a two-year extension
of the primary standards attainment date would be granted. If control
technology needed to attain was not available soon enough to permit
implementation in three years, an extension could be granted.
EPA is engaged in a number of projects to provide additional
guidance and reference publications which will be useful in determining
what RACT means in a wide variety of situations, and in making use of
such information in conducting various air pollution control operations.
These documents will be used in development of SIP revisions in the
C-3
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July 1976 - 1978 time period. Specifically, the guides* for use in
preparation of SIPs for several pollutants make reference to the various
publications that can be used to acquire information on RACT. EPA
expects these guides to be used as basic manuals (or references) in the
SIP preparation process. They address policy, conceptual, and technical
matters.
2. Specific Application of the RACT Concept
a. As an Aid in Defining BACT
The definition of BACT is based on either the applicable NSPS or
(when no NSPS is applicable) a case-by-case determination
(taking into account the factors listed under the BACT definition).
When no NSPS is applicable, the availability of information as to what
RACT is will provide a presumptive ceiling of emissions which could not
be exceeded and still qualify as BACT and, in most cases, will provide
assistance in determining how much lower than RACT the BACT limit might
be.
The Agency has already developed specific criteria applicable to
determinations of RACT for sources wishing to use tall stacks and/or
* These guides document policy statements, technical information and
guidance on control strategies relating to NOx, TSP, and oxidants.
They include a discussion of the Agency's concept of RACT, describe
procedural methods for determining RACT, and reference appropriate
detailed guidance. It should be emphasized that much material is
currently available on defining RACT. Support documents for emissions
standards (NSPS and NESHAP) provide valuable reference documents
for reaching a definition of RACT.
C-4
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SCS, and in relation to the application of certain measures for oxidants
and carbon monoxide controls. These policies are discussed below.
b. RACT Coupled with Tall Stacks and/or SCS*
In given instances, the technology envisioned by the BACT concept
may be available in a state-of-the-art sense; however, its retrofit onto a
specific existing source may be extremely onerous for economic reasons
or ill-advised for engineering or siting reasons. It is expected that
such instances will occur only in the cases of a few smelters and some
power plants.
Where these circumstances do occur, particularly where a source is
threatened with shutdown, the Agency believes that administrative relief
can be considered. Accordingly, where a source demonstrates to the
State (and the State thereafter demonstrates to EPA) that, as applied to
the source, BACT is economically unreasonable or technologically
unsound, EPA will approve a control strategy demonstration which, for
that source, is based upon reasonably available (as opposed to best
available) control technology coupled with unlimited stack height.
However, such a control strategy will only be approved as a temporary
measure for attaining and maintaining ambient air quality standards and
is conditioned according to the tall stack and SCS policies.
For this purpose, RACT is not necessarily equivalent to the
40 CFR 51, Appendix B definition; RACT becomes a factor only after it
*Extracted from EPA's Stack Height Increase Guideline, 41 F.R. 7450
(February 18, 1976).
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has been determined, on a case-by-case basis, that retrofit of BACT
on the existing source would be unreasonable. This requires that RACT
be determined by considering the processes, fuels, and raw materials
to be employed; the engineering aspects of the application of various
types of control techniques, process and fuel changes; the cost of
employing the available techniques; and the cost of certain control
techniques due to plant location, configuration, basic process design
and expected remaining life.
Remaining life and capacity are major factors determining the
reasonableness of an FGD installation for existing coal-fired power
plants. For these plants, the following should be considered in
determining reasonableness:
(i) Plant Life: If a plant has ten to fifteen years remaining
life or less, and is projected to operate at an annual average of no
more than 25 percent capacity, F^D installation might be considered
unreasonable. In such instances, the source owner should provide the
anticipated shutdown date, and that date must be included in the
compliance schedule.
(ii) Space Limitations: FGD may be unreasonable due to space
limitations.
C-6
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In the event that it is determined on a case-by-case basis that
FRD is not reasonable for a specific power plant, alternate control
measures must still be considered. The use of low sulfur coal and
coal washing, either separately or in combination, might be appropriate
options and acceptable in meeting RACT criteria. The capital as well as
operating costs of applying these control techniques are to be taken
into account in making the case-by-case determination and, when the
cost of using low sulfur coal is not significantly less than the cost
of FRD, coal washing alone might be considered RACT.* Only after
application of whatever measures are determined to be RACT would the
source be able to take any credit for stack height increase.
In the case of existing smelters, BACT will, in most cases, be
economically unreasonable and could, in some cases, result in shutdown.
Under such circumstances, RACT will usually eouate to control of all
strong gas streams through pronerly operated and maintained double
contact acid plants (or single contact acid plants where single acid
plants are already on line). Hhere increased acid olant capacity is
required to treat presently untreated strong gas streams, RACT for
such gas streams must be double acid plants.
Since RACT involves a decision that is based principally upon
economic and engineering considerations, the definition of RACT
* The circumstances under which the use of low sulfur coal would be
deemed to be unreasonable are expected to be extremely rare. EPA
analyses indicate that low sulfur coal supplies are sufficient to
accommodate demand.
C-7
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should be subject to future re-evaluation to determine if more effective
control measures would be applicable.
C. Reasonably Available Control Measures for CO and Ox
EPA's guidelines for the development of control measures aimed at
hydrocarbon and carbon monoxide sources* provide guidance as to
"reasonably available" control measures in terms of the stage of SIP
development and the severity of the air pollution problem. Reasonably
available measures are:
Source Control Measures
i) Inspection/Maintenance
ii) Vapor Controls for Organic
Solvents
iii) Petroleum Refinery,
Chemical Plant and Other
Industry Controls
iv) Vapor Controls for Gasoline
Marketing
v) HDV Retrofits
Transportation Measures
i) Transit Improvement
ii) Employer Incentives
iii) Parking Management/
Restrictions
iv) Traffic Management/
Restraints
Every one of these control measures is considered reasonably available
and should be included in SIP revisions where necessary for attainment.
* Policies for the Inclusion of Carbon Monoxide and Oxidant Controls
in State Implementation Plans (TCP Policy Paper), Office of Trans-
portation and Land Use Policy, Office of Air and Waste Management,
Environmental Protection Agency, December 1975.
C-8
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However, the most cost-effective mix of measures must be locally
detennined. The policies governing the application of control
measures are:
Policy for changing existing transportation and
stationary sources measures included in Oxidant
and Carbon Monoxide Control Strategies of SIPs:
EPA's policy is that revisions should be made to the existing
transportation and stationary source control measures for Ox and CO
in SIPs only if, on the basis of valid technical analysis, the measures
are found not to reduce pollutant emissions. In this case, changes
should be made. If states develop measures that are eaual or better in
effectiveness, in terms of reducing emissions, than are the reasonably
available measures EPA promulgated, then such substitute measures should
be adopted. (If standards cannot be attained by using the reasonably
available source control measures promulgated by EPA, new State measures
may supplement, but not replace, the EPA promulgated measures.)*
Policy for transportation measures being revised
pursuant to court orders or for new transportation
measures now being developed for addition to SIPs:
States are expected to adopt all reasonably available transportation
control measures.
* Gasoline rationing and catalytic retrofits for light-duty vehicles
(included in some SIPs) are not considered reasonably available measures
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Policy for inclusion of transportation measures
for non-attainment areas for which calls for SIP
revisions are issued:
Reasonably available measures should be identified,and the State
is to submit the required measures.
Policy for areas where transportation measures
are included in SIPs and where standards will
be attained by Clean Air Act deadlines:
Some areas to which transportation measures apply are not designated
air quality maintenance areas. However, SIP revisions may be needed
for standards maintenance. Needed SIP revisions should be determined
through the analyses required for maintenance revisions.
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APPENDIX D
Summary of States Issued Calls for SIP Revisions
July 1, 1976, and Pollutants for Which
Plan Revisions Are Required
POLLUTANTS*
TSP
S02
x
x
CO
0>
X
X
X
X
X
X X
XXX
XXX
X
X X
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Hawaii
Idaho
111inois
Indiana
Iowa
Kansas
Kentucky
* Where an "x" is shown, EPA has asked the State to revise its
implementation plan for that pollutant for at least one area.
x
x
N02
-------
POLLUTANTS*
TSP SO? CO Ox N02
Louisiana x
Maine x x
Maryland x x
Massachusetts x x x
Michigan
Minnesota
Mississippi
Missouri x x
Montana x x
Nebraska x
Navada x
New Hampshire x x
New Jersey x x x
New Mexico x x x
New York x x x
North Carolina x
North Dakota
Ohio x
Oklahoma
Oregon x x
Pennsylvania x x x
Rhode Island x x x
South Carolina x
* Where an "x" is shown, EPA has asked the State to revise its
implementation plan for that pollutant for at least one area.
D-2
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POLLUTANTS'*
State TSP S02 CO Ox N02
South Dakota x
Tennessee x x
Texas x
Utah x
Vermont x x
Virginia x x
Washington
West Virginia x x
Wisconsin x
Wyoming x
American Samoa
Guam
Puerto Rico x x
Virgin Islands
* Where an "x" is shown, EPA has asked the State to revise its
implementation plan for that pollutant for at least one area.
D-3
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APPENDIX E
List of Abbreviations, Symbols, and Acronyms
AQCRs
AQMA
AQMP
BACT
BOAs
CFP
CO
DOT
EPA
FEA
FGD
FMVCP
FRM
FY
GVW
gm/m
HC
HQ
MPO
NMQS
NESHAP
Air Quality Control Regions
Air Quality Maintenance Area
Air Quality Maintenance Plan
Best Available Control Technology
Basic Ordering Agreements
Clean Fuels Policy
Carbon monoxide
(U.S.) Department of Transportation
(U.S.) Environmental Protection Agency
Federal Energy Administration
Flue gas desulfurization
Federal Motor Vehicle Control Program
Federal Reference Method
Fiscal year
Gross vehicle weight
Grams per mile
Hydrocarbons
Headquarters (EPA)
Metropolitan Planning Organization
National Ambient Air Quality Standard
National Emission Standards for Hazardous
Air Pollutants
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NOX Nitrogen oxides
N02 Nitrogen dioxide
NSPS New Source Performance Standards
Ox Total oxidants
RACT Reasonably Available Control Technology
SCS Supplementary Control Systems
SIPs State Implementation Plans
SMSA Standard Metropolitan Statistical Area
SOX Sulfur oxides
S02 Sulfur dioxide
TCPs Transportation Control Plans
TIP Transportation Improvement Program
TRS Total reduced sulfur
TSM Transportation System Management
TSP Total suspended particulates
VMT Vehicle miles travelled
Micrograms per cubic meter
E-2
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