[Federal Register Volume 61, Number 241 (Friday, December 13, 1996)]
[Proposed Rules]
[Pages 65764-65778]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31343]



[[Page 65763]]

_______________________________________________________________________

Part V





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 51



Implementation of New or Revised Ozone and Particulate Matter (PM) 
National Ambient Air Quality Standards (NAAQS) and Regional Haze 
Regulations; Proposed Rule

  Federal Register / Vol. 61, No. 241 / Friday, December 13, 1996 / 
Proposed Rules  

[[Page 65764]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 51

[FRL-5661-5]
RIN 2060-AF34


Implementation of New or Revised Ozone and Particulate Matter 
(PM) National Ambient Air Quality Standards (NAAQS) and Regional Haze 
Regulations

AGENCY: Environmental Protection Agency (EPA).

ACTION: Advance notice of proposed rulemaking (ANPR).

-----------------------------------------------------------------------

SUMMARY: The EPA is providing advance notice of key issues for 
consideration in the development of new or revised policies and/or 
regulations to implement revised NAAQS for ozone and PM, and 
development of a regional haze program. The EPA is under court order to 
issue a proposed decision on whether to retain or revise the PM NAAQS 
by November 29, 1996, and to issue a final rulemaking for PM by June 
29, 1997. The Agency anticipates following the same schedule for the 
ozone standard and also intends to propose a regional haze program in 
mid-1997. If revised NAAQS replace existing NAAQS, there would be a 
period of time to phase in new requirements while continuing to address 
the requirements of the current programs. Further, ozone, PM and 
regional haze are products of interrelated chemical conversions in the 
atmosphere, and new approaches will be needed to identify and 
characterize affected areas and to assign planning, management and 
control responsibilities. This could lead to integrated implementation 
policies for ozone, PM and regional haze control programs. This ANPR 
provides a broad scientific and policy perspective on these issues and 
addresses implementation issues that have been identified, such as the 
need for regional strategies, and is a continuation of the advisory 
process first announced on September 11, 1995 (60 FR 47171) and further 
explained by the Agency on June 12, 1996 (61 FR 29719). Through today's 
action, the Agency is providing a brief discussion of a broad range of 
options, principles and questions related to each of these key issues. 
The options/principles/questions in this ANPR were designed to provide 
sufficient background information to stimulate public interest and 
comments and are not intended to indicate preferences or decisions by 
the EPA. By publishing this information at this time, the EPA is 
providing more time for the public to develop input and comments than 
would occur following the publication of the subsequent regulatory 
notices for the implementation strategies and regional haze program. An 
explanation and structure of the Federal Advisory Committee Act (FACA) 
Subcommittee is provided in SUPPLEMENTARY INFORMATION. Applicable terms 
and definitions are provided in the Appendix.

DATES: Written comments on this proposal must be received by February 
18, 1997.

ADDRESSES: Comments. Comments should be submitted (in duplicate if 
possible) to the Air and Radiation Docket and Information Center, 401 M 
Street, SW, Washington, DC 20460, Attention Docket Number A-95-38.
    Docket. The public docket for this action is available for public 
inspection and copying between 8:00 a.m. and 4:00 p.m., Monday through 
Friday, at the Air and Radiation Docket and Information Center (6102), 
Attention Docket A-95-38, South Conference Center, Room 4, 401 M 
Street, SW, Washington, DC 20460. A reasonable fee for copying may be 
charged.

FOR FURTHER INFORMATION CONTACT: For general FACA Subcommittee 
questions and comments, contact Ms. Denise Gerth, U.S. EPA, MD-15, 
Research Triangle Park, NC 27711, telephone (919) 541-5550. For 
specific questions and comments on the ANPR, contact Ms. Sharon 
Reinders, U.S. EPA, MD-15, Research Triangle Park, NC 27711, telephone 
(919) 541-5284.

SUPPLEMENTARY INFORMATION: The following communications and outreach 
mechanisms have been established:
    Overview information--A World Wide Web (WWW) site has been 
developed for overview information on the NAAQS and the ozone/PM/
regional haze FACA process. The Uniform Resource Location (URL) for the 
home page of the web site is http://www.epa.gov/oar/faca/
 Detailed and technical information--Available on the O3/PM/RH 
Bulletin Board on the Office of Air Quality Planning and Standards 
(OAQPS) Technology Transfer Network (TTN), which is a collection of 
electronic bulletin board systems operated by OAQPS containing 
information about a wide variety of air pollution topics. The O3/PM/RH 
Bulletin Board contains separate areas for each of the FACA 
Subcommittee's five work groups and includes meeting materials, issue 
papers, as well as general areas with information about the process, 
participants, etc. The TTN can be accessed by any of the following 
three methods:

--By modem; the dial-in number is (919) 541-5742. Communications 
software should be set with the following parameters: 8 Data Bits, No 
Parity, 1 Stop Bit (8-N-1) 14,400 bps (or less).
--Full Duplex.
--ANSI or VT-100 Terminal Emulation.

    The TTN is available on the WWW site at the following URL: http://
ttnwww.rtpnc.epa.gov. The TTN can also be accessed on the Internet 
using File Transfer Protocol (FTP); the FTP address is 
ttnftp.rtpnc.epa.gov. The TTN Helpline is (919) 541-5384.

I. Purpose and Objectives

    This ANPR outlines policy and technical implementation issues and 
identifies a broad range of options/principles/questions for each issue 
associated with the potential revision of the ozone and PM NAAQS and 
with the development of a regional haze program. Although the proposals 
to change the ozone and PM NAAQS have been made, the possibility that 
such changes may be promulgated necessitates this advance notice, as 
well as the ongoing implementation discussions under the FACA discussed 
elsewhere in this notice. The alternative approach of waiting until 
possible standard revisions are actually promulgated would, in the 
Agency's judgement, cause inevitable delays and disruptions in 
national, State and local efforts to achieve clean, healthy air, 
especially those related to attainment of the NAAQS for ozone. The 
ozone and PM NAAQS proposals are scheduled for publication in December 
1996 with final action scheduled for mid-1997. The EPA intends to 
propose a regional haze program in mid-1997.
    In advance of these actions, the EPA published an ANPR entitled, 
National Ambient Air Quality Standards for Ozone and Particulate 
Matter, on June 12, 1996 (61 FR 29719) which announced the Agency's 
plans to propose decisions on whether to retain or revise the ozone and 
PM NAAQS. That ANPR also described the FACA process and the 
Subcommittee for Ozone, PM and Regional Haze Implementation Programs 
(Subcommittee). The Subcommittee is composed of 60 representatives from 
State, local and tribal organizations; environmental groups, industry 
and trade groups (including small business representatives), 
consultants; academic/scientific communities; and Federal agencies. The 
organization of the Subcommittee includes a Coordination

[[Page 65765]]

Group and four work groups: (1) Base Programs Analyses and Policies 
Work Group, (2) National and Regional Strategies Work Group, (3) 
Science and Technical Support Work Group, and (4) Communications and 
Outreach Work Group. The Subcommittee was established under the Clean 
Air Act Advisory Committee (CAAAC) to provide advice and 
recommendations to the EPA on developing new, integrated approaches for 
implementing potential revised NAAQS for ozone and PM, as well as for 
implementing a new regional haze reduction program. Through this 
process, EPA is engaging in communications with segments of society 
that may be affected by the implementation of NAAQS and the regional 
haze program. This announcement is a further attempt to invite 
stakeholders to participate in the implementation development process, 
to assure that their concerns will be addressed and their options 
assessed, and, ultimately increase the effectiveness of NAAQS 
implementation strategies and the regional haze program.
    The implementation issues described in this ANPR form the basis of 
the Subcommittee's deliberations and for the most part were developed 
through the various work groups and the Coordination Group. The 
presentation of these issues and corresponding options/principles/
questions is designed primarily to provide advance notice for the 
public who are not directly involved in the FACA process. Interested 
readers are directed to EPA's TTN and WWW site for an up-to-date status 
of the work groups' and Subcommittee's deliberations on these issues. 
This includes work group issue papers with options and, where 
appropriate, draft recommendations.
    While the EPA is interested in considering new and innovative 
approaches to implementation, it is imperative to ensure that momentum 
is maintained in the current implementation programs, and that current 
programs and efforts such as the Ozone Transport Assessment Group 
(OTAG) continue in order to protect public health and welfare. As a 
consequence, the Subcommittee is providing recommendations to EPA 
regarding the development of an interim implementation policy (IIP), 
which was published in December 1996. The IIP will provide EPA's 
guidance to the State and local agencies on appropriate actions during 
the transitional period of time between any revision of the NAAQS and 
the development of new integrated implementation strategies. This is 
especially important since it is expected that any new NAAQS will be at 
least as stringent as the current NAAQS, and reductions in emissions to 
achieve the current NAAQS will be beneficial in achieving the revised 
NAAQS. While the IIP will provide guidance during the transition 
period, EPA will also develop implementation strategies for the 
potential new ozone/PM/regional haze programs.
    The final integrated implementation programs for ozone, PM and 
regional haze are being developed in two phases. In Phase I, the air 
quality management framework issues will be addressed (proposal--mid-
1997). Phase II will focus on more detailed control strategy 
development (proposal--mid-1998). These phases are described in more 
detail in subparagraph IV.

II. Scientific and Technical Discussion

    The following discussion relies on the Scientific and Technical 
Support Work Group of the FACA Subcommittee. This group is developing a 
draft conceptual model framing our current scientific understanding of 
ozone, fine particles and haze, the associated gaps and uncertainties, 
and based on the technical basis and issues underlying the integration 
of regulatory programs for ozone, fine particles and regional haze, and 
the specification of geographic scales required for air quality 
management. This conceptual model provides a technical basis for the 
Subcommittee's deliberations of these issues. This document is 
undergoing further review prior to acceptance by the CAAAC. Regarding 
the rationality of integration, the initial response of the Science and 
Technical Support Work Group was a qualified yes, given the regional 
nature of the pollutants (i.e., regionalization), spatial patterns of 
air quality indices, precursors, sources, atmospheric chemistry and 
meteorological processes which affect more than one pollutant, and 
control options. The following discussion focuses on the relationships 
between ozone and fine particles, given the close linkage between fine 
particle levels and regional haze (the widespread impairment of 
visibility in every direction, mostly attributed to fine particle light 
scattering and absorption), with the following assumptions:

--Understanding the emission sources and atmospheric processes which 
are responsible for elevated air pollutant levels requires an 
examination of urban and regional geographical scales;
--Ozone and fine particles may exhibit similar spatial patterns, 
although the frequency (and importance) of concurrent patterns is not 
well understood;
--Many of the emission precursors (and sources of precursors) to ozone, 
fine particles and regional haze are the same;
--Many of the atmospheric processes (chemistry and meteorology) 
affecting ozone, fine particles, and regional haze are the same; and
--Several critically-important information gaps exist which create very 
difficult challenges for air quality management of these pollutants.

A. Interacting Spatial Scales of Emissions, Atmospheric Processes and 
Air Quality Indices

    As explained in greater detail below, there are a variety of 
emissions that are precursors to elevated levels of ozone, fine 
particles, and regional haze and of sources to these emissions. 
Historically, attempts at air quality management of these problems 
focused on local sources in the context of an anonymous background term 
quantifying imported air quality. The evolution in our understanding of 
the spatial and temporal scales of the effects on ozone, fine 
particles, and regional haze of the emissions from all sources has, 
however, spawned the recognition of the need for a larger geographical 
perspective. This larger geographical perspective, which considers 
individual sources over regional, as well as local scales, is needed to 
support quantitative analysis of the relative contribution of the 
various source types and of their emission types (species) that 
contribute to nonattainment levels and regional haze. The need for an 
altered perspective has been recognized by the establishment of the 
Ozone Transport Commission (OTC), the OTAG, and the Grand Canyon 
Visibility Transport Commission (GCVTC).
    Air quality management in the metropolitan statistical area or 
consolidated metropolitan statistical area (MSA or CMSA) has worked 
well historically to control the local source effect on nonattainment 
problems. This is evidenced by the significant decrease in the number 
of ozone nonattainment areas over the past decade. As these controls 
have reduced emissions and as modeling tools have progressed, the role 
of the effect of sources beyond the MSA or CMSA and the varying spatial 
scales of air quality indices and atmospheric processes continue to be 
investigated and supported by a strong body of scientific evidence:

--The 1991 National Academy of Science (NAS) Report, Rethinking Ozone 
in Urban and Regional Scales

[[Page 65766]]

(National Research Council (NRC), 1991);
--The 1993 NAS Report, Protecting Visibility in National Parks and 
Wilderness Areas (NRC, 1993);
--The National Acid Precipitation Assessment Program (Trijonis et al., 
1990); and
--The Southern Oxidant Study (Chameides and Cowling, 1995).

    Recent analyses based on ambient air monitoring data (Rao, 1995) 
and regional acid deposition model air quality modeling (Appleton, 
1995) suggest a very broad spatial air pollution region covering the 
greater part of the Eastern United States (U.S.). These studies 
indicate that, while sources still have their largest influence in the 
near field, the zones of potential influence of source regions (e.g., 
an urban city) can under certain conditions extend out hundreds of 
kilometers (km) for ozone, fine particles, and regional haze. Moreover, 
these scales appear to be similar for ozone and fine particles. In 
other words, sources once thought to be remote with respect to 
nonattainment levels of ozone, fine particles, and regional haze are 
seen as potential contributors to those levels. The analyses suggest 
that chemical and meteorological processes which influence pollutant 
generation, air mass movement and pollutant removal (e.g., clouds and 
precipitation) are key factors in defining regional zones of influence. 
When the various nonattainment areas of the Eastern U.S. are surrounded 
by even conservative estimates of the zones of influence of these other 
sources, what results is a modeling domain that may span the greater 
part of the Eastern U.S. Accordingly, efficient air quality management 
requires addressing these additional sources, atmospheric processes and 
related impacts as scales of interactions over multiple spatial and 
temporal frames.
    In air quality management practice, the term ``transport'' has been 
used in a very broad context beyond the strict meteorological 
definition of the term. This broad context includes: (1) The overall 
regionalization of both the scale of pollutant distributions and zone 
of influence of sources, (2) the interaction (or effect of one area on 
another) among local, urban and regional source scales, and (3) meso 
and large-scale meteorological phenomena (such as recirculation due to 
stagnant high pressure systems and land-sea interactions, large-scale 
movement of air masses with fairly uniform motion, and other events 
perhaps as simple as widespread elevated temperatures). The prevalence 
and importance of biogenic volatile organic compounds (VOC) emissions 
(e.g., emissions from trees) in the Eastern U.S. are ``regionwide,'' as 
are many other area source emissions such as those emitted by motor 
vehicles. All of these regional attributes are enhanced by the 
relatively flat and consistent terrain in the East and Midwest, 
contrasting the greater topographic and meteorological effects in the 
Western U.S., although the West can also experience regional problems.
    Several physical and chemical events act together in determining 
pollutant concentrations over multiple space and time scales. Moving 
air masses carry all chemical species including precursors, fast-
reacting intermediates, and chemical sinks, as well as the specific 
pollutant species of interest (e.g., fine particles and ozone). Removal 
of pollutants occurs continuously through deposition. Also, the impact 
of these pollutants is not simply additive. Ozone (or precursors) 
transported from one location can affect ozone levels downwind by 
indirectly accelerating atmospheric chemical reactions through the 
production of chemical intermediates (e.g., hydroxyl radicals). Clouds 
play several roles in modifying concentrations by: (1) Dissolving 
soluble gases (e.g., nitric acid, sulfur dioxide (SO2), hydrogen 
peroxide) and generating aerosols through aqueous phase reactions, (2) 
circulating and venting pollutants to high altitudes where strong winds 
promote large horizontal transport, and (3) removing pollutants through 
precipitation. Cloud-related dissolution and transport also contribute 
to pollutant removal. Vertical air mass movements, or phenomena as 
basic as the daily mixed layer growth, affect air concentrations on 
various scales. Superimposed on these processes are a variety of 
emission sources with their own spatial, temporal and component 
(speciation) scales. Depending on location, pollutant and season, one 
particular spatial scale (e.g., urban) may (or may not) exert a 
dominating influence on air quality relative to another scale (e.g., 
regional). Even in cases where local and urban sources are responsible 
for most of the ``local'' air quality, an assessment of the 
contribution of distant sources to local air quality is required to 
reach such a conclusion. Thus, to avoid the exclusion of potentially 
important considerations in air quality analysis, ``regionality'' or 
``interacting scales'' is a more descriptive term (than transport) 
which encompasses the broader meaning and effects of several complex 
interacting phenomena operating over extensive and multiple time and 
space scales.
    The Eastern U.S. differs markedly, topographically and 
climatologically, from the West, so any extension to the West based on 
Eastern analyses (or vice versa) is not necessarily appropriate 
(important differences exist between Northern and Southern regions as 
well). The monitoring data and modeling analyses of the GCVTC process 
highlight the challenge of identifying and quantifying specific 
sources, some at great distances in order to estimate their effects in 
Western national parks and wilderness areas. The variations in 
topography, meteorology and source distribution across regions require 
that area- and case-specific differences be accounted for in any air 
management approach. The effects of emission reduction strategies 
should be viewed through multiple scales, considering regional and 
urban scale consequences (i.e., health and welfare protection).
    A few points summarizing ``interacting scales'' and ``regionality'' 
should be considered in air management practices:

--Air quality modeling and historical monitoring trends have shown that 
local air management practices have the greatest influence on near 
field concentration impacts.
--Analyses of observations in the Eastern U.S. reveal the existence of 
very broad multistate regions (interacting scales approaching linear 
scales of 1000 km or more) of elevated pollutant levels and zones of 
influence (Rao, 1996).
--Air quality modeling data for the East suggest that similar regions 
of influence exist for ozone and fine particles (Dennis, 1996), 
although only sparse monitoring data exist to support these 
similarities.
--Modeling analyses for the Grand Canyon National Park (and other) 
Class 1 areas show that fine particles and precursors causing 
visibility impairment episodes are derived from both nearby (less than 
50 km) and more distant (up to 1000 km) regions of influence (NRC, 
1993; GCVTC, 1996).
--Area and case-specific analyses are required to delineate reasonable 
geographic areas for air quality planning purposes because of the wide 
regional variations in meteorology, topography and source distribution.
--The use of terms such as ``transport'' or ``background'' inadequately 
describes the complex set of emissions, chemistry, meteorological 
processes and interacting scales which contribute to the 
regionalization of air pollution.

[[Page 65767]]

--Because of broad spatial extents and gradations of interacting scales 
ranging from regional down to sub-grid cell scales, an air quality 
assessment focusing on a particular scale (e.g., urban) must consider 
effects due to interactions across various space and time scales. The 
concept of a single MSA/CMSA nonattainment area may be inconsistent 
with the spatial and temporal scales for ozone, fine particles and haze 
problems.

B. Technical Basis and Considerations for Integrating Ozone, Fine 
Particles and Regional Haze Implementation Programs

    The technical and scientific rationale for underlying the 
integration of ozone, fine particles and regional haze air quality 
management practices is based on a mix of empirical observations, 
atmospheric processes and practical administrative concerns. While this 
discussion focuses on common attributes across pollutant groups, it is 
important to recognize and distinguish those attributes where there is 
little linkage. Many examples and inferences presented here tend to 
reflect what is known about Eastern U.S. air quality issues (e.g., 
ozone) with possibly little relation to Western U.S. phenomena. At the 
risk of generalizing (and simplifying) air quality descriptions for 
illustrative purposes, recognition that a generalized approach cannot 
operate effectively everywhere must be retained. The discussion focuses 
on the relationship between ozone and fine particles, with the implicit 
assumption that fine particle levels and chemical composition directly 
relate to regional visibility impairment, given the strong relationship 
between the constituents of fine particles and the manmade portion of 
visibility impairment. Regional haze is a widespread, largely uniform 
impairment of visibility in every direction over a large area, mostly 
due to light scattering from fine particles from multiple sources.
1. Empirical Evidence for Integration
    Ozone and PM-10 (particles with an aerodynamic diameter less than 
or equal to a nominal 10 micrometers) concentrations in the Eastern 
U.S. can exhibit similar spatial patterns during summer time episodes 
(Northeast States for Coordinated Air Use Management (NESCAUM), 1995). 
Analyses of PM data consistently indicate that fine particles 
constitute the majority mass fraction of PM-10 in the summertime East 
(EPA, 1996). In combination, these observations qualitatively imply 
concurrence of elevated ozone and fine particles. However, 
quantification of the similarity and frequency of such events is 
severely restricted by a lack of a fine particles data base in the 
East. While more data exist in certain Western locations, the episodic 
relationships between ozone and PM appears to be more complex than in 
the East. For example, a major component of the fine particle problem 
in Los Angeles (as well as the San Joaquin Valley, Salt Lake City and 
Denver) is wintertime formation of ammonium nitrate, which is not 
stable at the high temperatures associated with elevated ozone. High 
levels of fine particles in Western nonattainment areas can impair 
visibility when high ozone concentrations are not observed. 
Nevertheless, ``smog'' events in Los Angeles are almost always 
accompanied by impaired visibility, and visibility is directly 
associated with fine particle levels. Although some limited empirical 
evidence is highly suggestive of area specific concurrent events, other 
considerations as described below provide a stronger rationale for the 
appropriate level of integration across ozone, fine particles and 
regional haze control programs.
2. Emissions and Atmospheric Process Linkages Across Ozone, Fine 
Particles and Regional Haze
    Several connections exist among ozone, PM and the resulting effect 
of visibility impairment. The linkages are based on the existence of 
common emission precursors, source categories and atmospheric chemistry 
and meteorological processes which affect more than one pollutant. For 
example, emissions of oxides of nitrogen (NOX) potentially can 
lead to both ozone and fine particle formation. A combustion source 
often emits both SO2 (a fine particle precursor) and NOX (an 
ozone precursor). The sequence of atmospheric chemistry reactions 
underlying ozone formation is in part responsible for fine particle 
formation. Similar meteorological processes affect the movement, mixing 
and removal of ozone, fine particles and precursors. Some of these 
connections are complicated and will be explained more completely in 
forthcoming FACA science documents. The following are very brief 
descriptions of the connections across pollutant categories.

--Common ``direct'' precursor emissions. Emissions of NOX, VOC and 
carbon monoxide (CO) are considered precursors for ozone formation. The 
NOX, VOC and sulfur (SOX, mostly as SO2) emissions can 
also lead to fine particle formation through ``secondary'' atmospheric 
chemical reactions. Both ozone and a substantial fraction (which can 
vary greatly with season and location) of fine particles are the result 
of secondary formation processes. The major components (which also are 
highly variant) of secondary fine particles include sulfates, carbon 
(elemental and organic) and nitrates. The fraction of fine particles 
due to secondary processes is highly variant in space and time. During 
certain conditions (e.g., available ammonia, negligible sulfate, low 
temperatures), NOX emissions can lead to fine PM ammonium nitrate 
formation. Several directly-emitted organic compounds contribute to 
fine particle organic aerosols. These organic compounds may contribute 
as ``primary'' organic aerosols, that is, they almost immediately 
condense to the aerosol phase during the emissions process or shortly 
downstream. Or, certain VOC (e.g., toluene) which exist as gases under 
most conditions can undergo atmospheric reactions and transform into 
condensible ``secondary'' organic aerosols. Thus, a VOC like toluene 
can contribute to both ozone or fine particle formation as a precursor 
emission.
--Common source categories. Based on the multiple roles of precursors, 
a particular source (natural or anthropogenic) emitting one precursor 
(e.g., NOX or VOC) can affect ozone and fine particles, and a 
single source emitting multiple precursors (e.g., combustion process 
releasing NOX, VOC, CO and SOX) can affect multiple pollutant 
source categories. In this case, integration is not dependent on 
atmospheric chemical linkages. This commonality among sources should 
lead to a more consistent approach in estimating emissions of multiple 
precursors within a specific source category. For instance, a 
consistent approach needs to be applied for estimating and projecting 
both NOX and SOX emissions from a combustion source.
--Interaction of atmospheric chemistry reaction cycles and ``indirect'' 
precursors. Much of the general atmospheric chemistry involved in ozone 
formation can affect fine particle formation, as alluded to above, in 
certain instances. For example, ozone is the major initiator of 
hydroxyl radicals, a chemical intermediate which converts SO2 and 
nitrogen dioxide (NO2) to more oxidized sulfate (e.g., sulfuric 
acid) and nitrate (nitric acid) forms. Both sulfates and nitrates can 
contribute to fine particle formation. Clearly, a linkage between ozone 
and fine

[[Page 65768]]

particles exists through the role of ozone in generating hydroxyl 
radicals. Note that this linkage between ozone and fine particles is at 
the process level and does not require coexisting ``high'' ozone and 
fine particle levels. Many other important linkages involving oxidizing 
chemical species (radicals and peroxides) exist within the NOX, 
VOC, SOX, ozone chemistry system. A correct characterization of 
the basic ozone chemistry and the associated linkages among the 
precursors is needed to predict the affect of changing emissions on air 
quality indices. Consequently, the predictive air quality models used 
to assess ozone and fine particle impacts should include a basic core 
set of atmospheric chemical reactions (i.e., a gas phase ozone 
chemistry mechanism).

    Because of their common atmospheric chemical linkages, many 
precursors associated with one pollutant might be considered as an 
``indirect'' precursor for another pollutant as well. Virtually all 
precursor emissions (NOX, SOX, VOC, CO) undergo initial 
attack by hydroxyl radicals and participate in the general cycling of 
various chemical intermediate species. Therefore, precursors that 
typically may not be associated with a particular secondary pollutant, 
such as the effect of VOC on either sulfate or nitrate, indirectly 
participate through their roles in atmospheric chemistry. In this 
general context, the term precursor does not imply a positive effect on 
an associated secondary species as the emission precursor may only 
share in certain atmospheric chemical processes without leading to 
increases in a secondary pollutant. Multiple possibilities exist. For 
example, NOX, which affects the cycling of hydroxyl radicals 
(which convert SOX to sulfate), could act indirectly as a sulfate 
particle precursor. The majority of VOC species that do not transform 
into organic aerosols could nevertheless be fine particle precursors 
through their general role (i.e., cycling of radicals) in atmospheric 
chemistry. Nitrogen oxides could serve as indirect precursors for 
aerosol sulfate formation. This ``universal'' pool of precursors does 
not imply that reductions of any specific precursor lead to reductions 
of every pollutant. Just as reductions in NOX potentially can 
raise local ozone levels, a reduction of a fine particle precursor 
possibly can increase ozone or increase a different fine particle 
component (e.g., SOX reductions leading to increased ammonium 
nitrate, or NOX reductions increasing sulfate formation). These 
examples are some of several conceivable indirect precursor 
relationships. Many other relationships with similarly unknown degrees 
of effect exist. Thus, integrated implementation is far from a 
straightforward exercise. Complex air quality simulation models (in 
combination with simpler models and receptor/observational methods) 
which include approximations of these process linkages will need to be 
exercised to account for the multiple nonlinearities and positive and 
negative feedbacks. This complexity demands that high quality emission 
inventories, technically credible models, and spatially and temporally 
representative monitoring data will be needed in predicting pollutant 
concentrations and control strategies.
3. Integrating Control Strategy Development Through an Air Quality 
Modeling Approach
    What does integration mean from an implementation perspective? 
Given the complex mechanisms for and linkages between ozone and fine 
particle formation, the formulation of control strategies should 
acknowledge the need to optimize control options; control of one 
precursor might affect both ozone and fine particles or might be 
detrimental for one or both. For example, one might start with ozone 
management strategies being developed as part of ongoing urban and 
regional planning efforts and attempt to quantify the future impact on 
secondary aerosols. On the other hand, because NOX controls might 
increase ozone levels in certain localized urban areas or because 
SO2 reductions might lead to increased concentrations, efficient 
air quality management would attempt to optimize the system in relation 
to VOC, NOX and SOX emission reductions.
    The real benefit of integration is the prospect of a more 
systematic, efficient and comprehensive treatment of emission 
inventories, episode selection, and atmospheric physics and chemistry 
that might empower the air quality manager to characterize source-to-
receptor effects in an orderly way. The addition of data on the costs 
and effectiveness of control options would enable the air quality 
manager to identify the cost-effective means for attaining a variety of 
air quality goals.
    To this end, emission bases underlying most current ozone modeling 
efforts include most of the sources for aerosol formation (but not 
necessarily the aerosol-specific emissions such as organic aerosols 
from motor vehicles). Notable exceptions include emissions from many of 
the fugitive primary particle sources and most sources of ammonia. The 
result of this hypothetical exercise could produce the residual 
aerosol- (and regional haze-) related air quality benefits from an 
ozone precursor control perspective. [Additional analysis directed at 
the specific needs for meeting fine particle and visibility concerns 
could follow this ozone oriented approach. Ideally, an objective (and 
likely iterative) ability to assess the benefits and tradeoffs 
associated with managing all three pollutant categories would evolve.] 
Although this example does not represent ``full'' integration given the 
unidirectional information flow (ozone to particles), it does 
acknowledge similarities among programs and avoids mistakes and 
inefficiencies incurred from independent analyses. Aside from any 
direct regulatory policy, the linkages across pollutants and emissions 
are reasons by themselves for planning for more effective and efficient 
development and use of emissions, air quality models and monitoring 
networks which address sometimes confounding multiple pollutants and 
their related health/welfare effects, and control options.
4. Distinctions Among Ozone, Fine Particles and Regional Haze
    Concurrent ozone and fine particle episodes may be expected to 
occur given similarities in the meteorological and atmospheric 
chemistry processes underlying ozone and fine particle formation, 
maintenance and destruction. As discussed above, the linkages 
associated with emission source categories and physical and chemical 
processes exist more frequently than the occurrence of coepisodic 
events. For example, several basic atmospheric chemical reactions 
involved in ozone and fine particle formation occur whether or not high 
ozone and fine particle levels are generated in the atmosphere. 
Nevertheless, several distinctions among the pollutants persist. These 
differences include the contribution of primary particles to total fine 
particles (and especially PM-10) and wintertime (actually 
nonsummertime) fine particle events. Some primary particles are 
generated by strong wind conditions (e.g., soil/geologic material) and 
other mechanical processes (e.g., roadway fugitives). A fraction of 
primary PM peaks in summer in most of the Western third of the country 
where there is little precipitation for 6-8 months per year, and dry, 
windy conditions lead to the generation and movement of geologic 
materials. As discussed earlier, ammonium nitrate, a significant fine

[[Page 65769]]

particle component in the West, is stable at relatively low wintertime 
temperatures and therefore does not form significant levels during the 
high summertime temperatures. Meteorological effects which influence 
the creation, maintenance or removal of high levels of ozone and fine 
particles may be significantly different between pollutants, regions of 
the country, and times of the year. Other specific emissions-driven 
events such as forest burning and wintertime woodsmoke (a major 
wintertime source of urban PM) bear virtually no relation to ozone. 
Many of these PM episodes can be dominated by either primary or 
secondary fine particle components, or by primary anthropogenic coarse 
PM emissions. Research exploring the frequency and characterization of 
coepisodic and uni-episodic events would yield further insight into 
underlying causes of events and provide direction for integrated 
implementation opportunities.
    Visibility protection presents several additional considerations 
beyond the scope of topics covered under ozone and fine particles. 
First, fine particle concentrations that are far below any potential 
NAAQS can adversely affect visibility in a significant manner, 
particularly in more pristine environments, such as Federal Class I 
areas in the rural West. For this reason, visibility management needs 
to consider the protection of ``clean'' days separately from 
assessments focusing on highly impaired days. The meteorology and 
emissions characteristics during ``clean'' days differ from those 
common during high pollution episodes. This concern raises complex 
technical issues related to the ability of models and monitoring 
instruments, which often have been designed or tested for meeting 
``high'' concentration requirements, to characterize ``low'' level 
conditions. Second, relative humidity plays a significant role in 
enhancing visibility impairment, particularly in the East. In humid 
conditions, particularly above 70 percent relative humidity, sulfates, 
nitrates, and certain organics readily take on water and expand to 
sizes comparable to the wavelength of light. Particles in this size 
range (e.g., 0.1 to 1.0 micron in diameter) are efficient scatterers of 
light. Third, unlike the NAAQS approach of setting a national standard, 
the regional haze program has as its goal the prevention of any future, 
and the remedying of any existing, impairment of visibility in 
mandatory Federal Class I areas which impairment results from manmade 
air pollution. States are required to make ``reasonable progress'' 
toward this goal. The notion of background versus manmade air pollution 
raises several technical and policy challenges, particularly in the 
protection of visibility in ``cleaner'' environments, where small 
increases of fine particles can lead to significant visibility changes.
    Generally, PM-10 is not considered in the integration discussions 
of ozone, fine particles and regional haze. This is because the coarse 
fraction (e.g., greater than 2.5 micron) typically is derived from 
primary emissions (e.g., fugitives and geologic material) with little 
association to ozone from a process (or episodic) perspective. In 
addition, visibility impairment leading to regional haze is 
overwhelmingly associated with the fine particle fraction of PM-10.

C. Major Technical Issues

    The principal technical issues associated with integrated air 
quality management involve the adequacy of data bases and models 
(including specific process formulations) on which to base credible 
assessments. Generally, the tools (ambient data, models and emissions 
data) underlying ozone analyses are better developed than those for 
fine particles. Major efforts in chemical mechanism development, 
ambient monitoring methods and establishment of national and special 
study efforts for monitoring, emissions and modeling have resulted in a 
wealth of information and familiarity with these tools. This relative 
abundance of knowledge for ozone should not be construed as a science 
lacking uncertainty as significant technical issues remain (e.g., the 
current North American Research Strategies for Tropospheric Ozone 
(NARSTO) effort) and even more are yet to be defined. A sampling of 
these issues include the representativeness of emission inventories, 
particularly biogenic emissions; uncertainties in the modeling system 
(e.g., chemical characterizations of aromatics and biogenics, treatment 
of vertical mixing processes); difficulties in monitoring techniques 
(carbonyls, NOX-NO2, polar VOC); and lack of measurements 
(e.g., total reactive nitrogen, upper air data). In some cases, these 
gaps are significant and could compromise our ability to perform highly 
credible ozone analyses and to ascribe confidence levels in our 
results.
    Consideration of fine particles and regional haze presents several 
additional issues which are a result of: (1) A very complex multiphase, 
multicomponent, multiseason aerosol system; (2) the complex covariance 
of these data; and 3) the present PM-10 form of the NAAQS which has 
resulted in few regulatory needs to hasten an improved 
characterization. Significant concerns include major positive and 
negative measurement artifacts (related to gas-particle phase changes); 
a simple lack of ambient data, especially urban fine particle 
measurements; poor quality assurance/control of ambient sampler data; 
emissions data with poor general spatial applicability; limited 
availability, limited application and evaluation of regionally-accurate 
air quality models; and highly empirical treatment of organic aerosols 
within the available models. These gaps are interconnected in the sense 
that quality model evaluation and improvement rely on available quality 
measurements. The issue is further complicated by difficulties (due to 
complexities, lack of precedence and resource constraints) in designing 
a data collection program to evaluate a gridded model's ability to 
characterize fine particles covering wide scales of time (annual, 
seasonal, daily) and spatial resolution (regional, urban, local). On 
the positive side, a strong history of using ambient data for PM source 
apportionment is probably more adaptable to fine particle analyses than 
ozone, given that the measurable components of secondary fine particles 
(e.g., sulfate) have some direct linkage to precursors, whereas an 
ozone measurement by itself provides no inference regarding 
contributing precursors.
    Several interesting atmospheric chemistry questions remain to be 
answered; two examples include nitrate fine particle formation and 
organic aerosols. Where and when do ammonia and sulfate become limiting 
factors in ammonium nitrate formation? The relatively abundant nitrate 
fine particles at sites in the urban West contrast with abundant 
regional sulfate fine particles in the East. Substantive decreases in 
SO2 emissions could lead to increased nitrate fine particle 
formation in the East if sufficient ammonia (a highly uncertain 
emissions category) is available. What impacts will NOX emission 
reductions have on fine particles? Many possibilities exist. If nitrate 
is significant, one would expect a reduction in fine particles. 
However, if sufficient sulfur remains available, NOX reductions 
could increase or decrease sulfate formation (and, therefore, fine 
particles) depending on a complex cycling of oxidizing species. 
Reductions in NOX emissions could actually lead to sulfate 
increases by reducing competition (between SOX and NOX) for 
gas phase oxidizing radicals, or by increasing peroxide levels leading 
to

[[Page 65770]]

greater aqueous phase sulfate production. Or, NOX reductions could 
slow down sulfate formation through overall reductions in ozone and 
other oxidants. This relationship is very complex, and we must exercise 
caution in associating fine particle benefits with NOX reductions 
in the Eastern U.S.
    What are the relative contributions of primary and secondary 
organic aerosols across varying spatial (and time) scales? The 
potential for large secondary organic aerosol production from biogenic 
sources (e.g., pinene emissions) exists throughout the East. How 
significant are biogenic-derived aerosols compared to local/urban 
contributions from primary anthropogenic organic aerosols? How 
different are these relative contributions across seasons, given that 
secondary organic aerosol formation increases during the summer? Many 
uncertainties underlie the integration of primary and secondary 
particles, aside from integrating particles and ozone. For instance, 
what are the interactive roles exerted by elemental carbon emissions 
and other products of incomplete combustion and geologic materials in 
both primary contribution to PM and as formation nuclei for highly 
complex secondary PM? On balance, the ability to perform ozone air 
quality assessments far exceeds that of fine particles. However, the 
infrastructure for conducting fine particle analyses appears to be in 
place as a result of progress gained from ozone and acid deposition 
modeling and existing monitoring programs for ozone and visibility 
(i.e., the Interagency Monitoring of Protected Visual Environments 
(IMPROVE) program). Finally, although uncertainties remain in 
transforming particles into visibility impairment within short 
averaging times, the IMPROVE methodologies for particle and visibility 
measurements (and the relationships between particles and visibility) 
are widely accepted.
    Specific issues across PM and ozone include the ability to 
formulate fully-integrated models accounting for multidirectional 
effects on several pollutants. For example, the formation of secondary 
organic aerosols is a loss mechanism for VOC which presently is not 
accounted for in ozone modeling efforts. Many other integration topics 
exist, and collectively there is uncertainty regarding the overall 
importance of one pollutant imparting an effect on another.
    Two basic issues span the gap between science and policy: (1) The 
manner in which tools are applied, and (2) accommodating scientific 
findings and uncertainties in air quality management decision making. 
The first topic reflects the concerns of how one applies deterministic 
(i.e., models that establish exact cause and effect relationships) and 
uncertain air quality models to probabilistic forms of the standard in 
ascribing rigid control requirements. The selection of ``severe'' 
meteorological episodes versus ``prototypical'' episodes for ozone and 
PM-10 modeling has been controversial and remains a difficult model 
application issue. Equally complicated is the emerging need to model 
seasonal and annual cases. The debate on the credibility of models is 
fueled by the manner in which they are applied as much as by concerns 
about their formulations and supporting data bases. The second topic 
acknowledges the need for conducting policy-relevant as opposed to 
policy-driven research and recognizing the different time scales 
operating in research and policy arenas (where the timeframe demands 
move much faster than research results). Extremely useful information 
emerges continuously from research programs, yet a separate, sometimes 
very significant, time-lag occurs before information is considered in 
the policy-setting process. Hence, opportunities must be available to 
incorporate the latest science into policy.

D. Integrating Models and Observations for Sound Air Quality Management 
Practice

    Much emphasis has been placed on the complementary and integrated 
use of models and ambient data in air quality management practice (Rao 
et al., 1996). Several facets are associated with this topic, ranging 
from the need to evaluate models with sound data bases to conducting 
fully integrated analysis optimized through the separate, strong 
attributes of data and models. As the technical debate on the use of 
models and data continues to mature, perceptions such as ``model'' or 
``data'' are replaced by the intelligent and integrated use of ``models 
and data.'' Clearly, the demand for measurements initiated by the 
National Academy of Sciences Ozone Report (NRC, 1991) to provide 
feedback information loops, as well as empirically-based corroboration 
of predictive tools, has been adopted by large segments of the air 
quality community and reflected in major efforts such as the 
Photochemical Assessments Measurement Stations (PAMS) and NARSTO.
    An appreciation of the strengths of models and observations can 
assist the understanding of current analyses and lead to improved 
techniques. A model's strength is its ability to: (1) Integrate an 
enormous spectrum of data (e.g., emissions and meteorological 
variables) and process understandings (e.g., chemical mechanisms and 
flow phenomena), and (2) serve as an exceptional space and time mapping 
tool. This latter attribute reflects the model's unique ability to 
predict into the future and to supplement (or fill in) present gaps in 
observed data. The process formulations embedded in models enable the 
addressing of many ``what if'' questions related to emissions control. 
However, models are engineering tools that invoke substantial 
approximations of scientific understandings of natural phenomena, both 
their formulations and application methods reflect engineering 
principles more than fundamental science. Observations provide a basis 
for testing and diagnosing models. Also, in some instances, 
observations add another benefit. They can capture process-type 
relationships by themselves (e.g., the emergence of observational-based 
models for defining NOX and VOC control preferences). However, 
often observations are very sparse.
    Applied in isolation, the use of either models or observations 
alone is not desirable. Space and time constraints often bias the 
interpretation of observational analyses (i.e., analysis results 
reflect time and space of monitors which may or may not reflect the 
scales of concern). Models suffer from a very large spectrum of 
weaknesses because they attempt to portray so many phenomena. Most 
critical though is the risk of using a potentially biased model that is 
assumed bias free. The integrated use of observations and models 
mitigates the individual weaknesses of both approaches and produces a 
powerful air quality management tool, especially when applied in an 
iterative (even retrospective) manner to continually assess model 
results and related implementation strategies.

E. Summary

    Air quality assessments for fine particles, ozone, and regional 
haze must consider emissions, meteorological processes, atmospheric 
chemistry, and deposition, all of which interact over multiple spatial 
and temporal scales. Examining in detail the sources only from the MSA/
CMSA surrounding the monitor reporting nonattainment levels of air 
quality may need to be augmented (on a space and time basis) for 
responsibly allocating those levels to the sources causing them. When 
examining the issues on expanded time and space scales, the air quality 
management should also take into account the similarities of these air 
quality indices,

[[Page 65771]]

such as their common precursor emissions (e.g., NOX, VOC); common 
emissions sources (e.g., mobile sources, stationary and area source 
combustion emissions, biogenics); and shared chemical and 
meteorological processes (e.g., transport, transformation, 
precipitation, and removal).
    The principal technical issues associated with integrated air 
quality management involve the adequacy of data bases and models 
(including specific-process formulations) on which to base credible 
assessments. Many of these gaps are interconnected since model 
evaluations rely on available high quality measurements of emissions, 
atmospheric processes (such as wind fields) and ambient concentrations. 
On balance, the ability to perform ozone air quality assessments far 
exceeds that of fine particles, due mostly to the development of ozone 
research as well as a lack of urban fine particle measurements and 
important emissions components. However, many of the components of the 
infrastructure for conducting fine particle analyses appears to be in 
place as a result of progress gained from ozone, acid deposition, and 
visibility modeling and monitoring programs. The integrated application 
of models and observed data is strongly encouraged. In combination, 
both approaches help to mitigate the weakness of an isolated approach, 
producing a powerful tool for air quality management.

III. Schedules

    Both the ozone NAAQS notice of proposed rulemaking (NPR) and the PM 
NAAQS NPR are expected to be published in December 1996 with 
promulgation of both the PM and ozone NAAQS scheduled for mid-1997. The 
previously-described IIP will be proposed for comment in late 1996 and 
finalized in mid-1997 and will apply during the time period following 
promulgation of any revised NAAQS. The ozone, PM and regional haze 
programs are tentatively planned to be developed on a common schedule.
    As indicated above, the integrated implementation strategy for 
ozone and PM NAAQS will be issued in two phases. The Phase I 
implementation strategy which will give guidance to State and local 
agencies concerning actions prior to and including designation of areas 
not attaining potential new PM and ozone NAAQS will be proposed in mid-
1997 with a public comment period prior to adoption of the strategy. 
The EPA expects that the Subcommittee and CAAAC will make 
recommendations regarding formulation of the Phase I strategy prior to 
proposal. In mid-1998, the Phase I implementation strategy will be 
finalized. (Note that prior to recommendations from the Subcommittee 
and CAAAC, EPA will refer to areas not attaining new NAAQS as 
nonattainment areas.)
    Also in mid-1998, the Phase II implementation strategy will be 
proposed. This strategy will provide guidance for the events and 
actions between area designation and submittal and approval of State 
implementation plans (SIP's). This will include control strategies. The 
EPA expects that the Subcommittee and the CAAAC will also make 
recommendations regarding formulation of the Phase II strategy prior to 
proposal. In mid-1999, the Phase II implementation strategy will be 
finalized.
    Unlike the NAAQS, the regional haze rule will not set a specific 
ambient pollutant standard. However, the rule will include criteria for 
measuring reasonable progress and the methods to measure progress. The 
EPA currently intends to publish the regional haze NPR in mid-1997 
(with Phase I). The EPA is exploring ways to coordinate regional haze 
program implementation with NAAQS implementation.

IV. Framing of Phase I Implementation Issues

    The Phase I issues below were identified by EPA with substantial 
input from the Subcommittee and represent the priority issues which 
must be addressed as soon as possible after the revision of the NAAQS. 
These issues and options are subject to change as the FACA process and 
deliberations continue. The options/principles/questions which are 
presented are not all inclusive and are designed to stimulate public 
discussion. These options/principles/questions are not intended to 
indicate preference or represent any decisions and are under active 
FACA consideration. Consistent with the broad mandate given to the 
Subcommittee, the EPA is actively seeking new ways to implement the 
potential revised ozone and PM NAAQS and regional haze programs, and at 
this time is not evaluating legal constraints in the Clean Air Act 
(Act) which may limit or change some policy options identified below. 
For example, revision of an ozone or PM NAAQS will require EPA to 
determine the effect of the new planning requirements triggered by the 
revised NAAQS on the existing planning requirements in the various 
subparts of part D of title I of the Act. The EPA is not addressing 
such legal issues in this notice. The purpose of this advance notice is 
to stimulate public interest and comments on a wide range of policy 
issues and options, without limitation at this stage, from legal 
constraints. After the FACA process produces policy options and 
recommendations and as the EPA develops a proposed and final integrated 
implementation strategy, the EPA will consider legal authorities and 
constraints which may be present in the current Act.
    The issues identified below regarding implementation of a potential 
ozone or PM NAAQS revision generally use as their frame of reference 
the basic planning requirements of part A of title I of the Act and the 
basic nonattainment planning requirements of subpart 1 of part D of 
title I of the Act. Similarly, the discussion below addressing 
development of a regional haze program does not analyze pertinent legal 
issues but endeavors to use as a general frame of reference the 
visibility protection provisions in sections 169A and 169B of the 
current Act. Rather than focusing on the statutory requirements, 
however, the following discussion identifies technical and policy 
issues and options under consideration. Again, interested readers are 
directed to the EPA TTN and WWW site for an up-to-date status of FACA 
deliberations on these issues. The EPA is including the issues with 
sufficient background information in this ANPR to allow interested 
individuals to comment on the development of the implementation 
strategies.
    Upon a proposal to revise current NAAQS or promulgate new NAAQS for 
ozone and PM and regulations for regional haze, the following 
characterize the most important implementation issues identified so far 
that should be considered. The issues are divided into two phases of 
implementation development. The options/principles/ questions are 
presented as a broad range of possibilities and are not listed in any 
order of preference.

A. Phase I Issues

1. Regional Haze Program Development
    In order to place the following discussions on the issues 
associated with joint programs in the proper perspective, this section 
begins with a discussion of issues and questions related to the 
development of a regional haze program. As described in section II, 
regional haze is produced by emissions of fine particles and their 
precursors from a multitude of manmade and natural sources located 
across a broad geographic area. Fine particles impair visibility by 
scattering and absorbing light. Average visual range in most of the 
Western U.S. is

[[Page 65772]]

100-150 km. In most of the East, the average visual range is less than 
35 km. The following discussion includes general background on the 
existing visibility protection program, recommendations to EPA for 
improving regional haze conditions, and key issues for consideration in 
a new regional haze program.
    Under a national visibility goal that calls for the prevention of 
any future, and the remedying of any existing, impairment of visibility 
in mandatory Federal Class I areas which impairment results from 
manmade air pollution, the EPA's 1980 visibility regulations addressed 
local visibility impairment that was ``reasonably attributable'' to a 
single source or small group of nearby sources. Under these rules, the 
36 States containing mandatory Federal Class I areas were required to: 
(1) develop a program to assess and remedy visibility impairment from 
new and existing sources, (2) develop a long-term strategy to assure 
progress toward the national goal, (3) develop a visibility monitoring 
strategy, (4) consider ``integral vistas'' outside of Federal Class I 
areas in all aspects of visibility protection, and (5) notify Federal 
land managers (FLM) of proposed new major stationary sources and 
consider visibility analyses conducted by FLM in their permitting 
decisions.
    The 1980 rules were designed to be the first phase in EPA's overall 
program to protect visibility. The EPA explicitly deferred action 
addressing impairment from regional haze due to the need for further 
research and improvements in several technical areas, including 
visibility monitoring, modeling, and the relationship between specific 
emitted pollutants and visibility impairment. The GCVTC was established 
to assess scientific and technical information regarding adverse 
impacts on visibility in the transport region and provide 
recommendations to the EPA for addressing these adverse impacts. Within 
18 months of receipt of the GCVTC recommendations, the Administrator is 
required to carry out her ``regulatory responsibilities under section 
169A, including criteria for measuring 'reasonable progress' toward the 
national goal.'' In developing the regional haze program, EPA will also 
have the benefit of recommendations from the 1993 report of the NRC 
Committee on Haze in National Parks and Wilderness Areas, Protecting 
Visibility in National Parks and Wilderness Areas, and from the work of 
the FACA Subcommittee on Ozone, PM and Regional Haze Implementation 
Programs. The following addresses key issues for consideration in 
developing a regional haze program.
    Issue: Applicability--Currently, States containing mandatory 
Federal Class I areas where visibility has been identified as an 
important value, or having sources which may reasonably be anticipated 
to cause or contribute to any impairment of visibility in any such 
area, must revise their SIP's to make reasonable progress toward the 
national visibility goal. Existing visibility regulations apply to the 
36 States containing one or more mandatory Federal Class I areas. 
Studies have shown that regional haze can be caused by fine particles 
that are transported hundreds or even thousands of kilometers. Thus, 
sources in States having no mandatory Federal Class I areas could 
potentially contribute to impairment in Federal Class I areas in other 
States. The regional haze program should address the potential 
applicability to all States.
    Issue: Regional Haze Planning Areas--It has been recognized in many 
forums that programs to mitigate regional haze may require multistate 
or regional approaches to technical assessment, planning, and/or 
control strategy implementation. Potential regional approaches are 
currently under discussion through the FACA process. Key questions to 
be considered are: (a) if regional approaches are taken, should one set 
of multistate groupings be developed to address ozone, PM, and regional 
haze implementation programs, or should separate approaches be taken 
for each of the three programs; and (b) should existing or new 
institutions be responsible for future planning activities related to 
these three programs?
    Issue: Definition of Reasonable Progress--The term ``reasonable 
progress'' was not specifically defined in the 1980 visibility 
regulations for purposes of regional haze. Current regulations require 
SIP's to contain such emission limits, schedules of compliance and 
other measures as may be necessary to make reasonable progress toward 
the national goal, including: (1) requirements for best available 
retrofit technology (BART) for certain major sources of pollution, and 
(2) a long-term strategy for making reasonable progress toward meeting 
the national goal.
    In the June 1996 report from the GCVTC, the Public Advisory 
Committee defines reasonable progress as ``achieving continuous 
emission reductions necessary to reduce existing impairment and attain 
steady improvement in visibility in mandatory Federal Class I areas, 
and managing emissions growth so as to prevent perceptible degradation 
of clean air days.'' In the GCVTC report, visibility impairment is 
defined in terms of total light extinction and deciview. The 
legislative history of the 1990 Amendments to the Act also addresses 
the issue of reasonable progress and perceptible improvement. Senator 
Adams, the sponsor of the 1990 revisions to the visibility protection 
program stated that, ``At a minimum, progress and improvement must 
require that visibility be perceptibly improved compared to periods of 
impairment, and that it not be degraded or impaired during conditions 
that historically contribute to relatively unimpaired visibility.''
    Question: What should be the criteria for measuring reasonable 
progress?
    The assessment of reasonable progress can involve quantitative and 
nonquantitative factors. From a quantitative perspective, measurement 
of reasonable progress could incorporate assessments of visibility 
trends, emission reductions, or a combination of both. Tracking 
visibility trends suggests a periodic assessment of visibility 
conditions (e.g., averages of 20 percent best and worst days, annual 
average) as derived from visibility monitoring data and use of a common 
metric nationally. The light extinction coefficient would be a logical 
choice since it has been used widely for years and is routinely 
calculated from optical and aerosol measurements for all IMPROVE sites. 
Tracking progress will also require the initial documentation of a 
baseline level of anthropogenic visibility impairment at mandatory 
Federal Class I areas. The GCVTC has recommended an emission reduction 
target approach, including review of compliance with an SO2 
percent emission reduction target in the year 2000 and 5-year progress 
reviews thereafter. Nonquantitative progress factors could address 
whether a State has taken certain administrative or technical actions 
determined necessary for measuring and achieving progress over time.
    Other questions related to reasonable progress include:
    Question: How frequently should progress be measured?
    Question: Since monitors are located at only about one-quarter of 
the 156 mandatory Federal Class I areas, how can progress be 
demonstrated for sites without monitoring?
    Question: Should reasonable progress be demonstrated on a 
``regional'' basis (i.e., for groups of Federal Class I areas), with 
certain IMPROVE sites deemed

[[Page 65773]]

representative of others lacking monitoring?
    Question: Would tracking of emissions reductions and conducting 
regional modeling be an acceptable surrogate to using monitoring data?
    Question: Would the GCVTC approach, which specifies maintaining 
(rather than improving) average ``clean day'' conditions, be 
appropriate for areas with higher levels of anthropogenic pollution and 
thus greater room for improvement (such as most of the Eastern U.S. and 
selected areas in the West)?
    Question: How should a reasonable progress determination take into 
account the degree of improvement in visibility which may reasonably be 
anticipated, the costs of compliance, the time necessary for 
compliance, and the energy and nonair quality environmental impacts of 
compliance, and the remaining useful life of any existing source 
subject to such requirements?
    Question: What should be required in a State's long-term strategy 
for making reasonable progress under the regional haze program?
    One element of the reasonable progress demonstration should 
describe the State's strategies for preventing future impairment and 
ensuring continued progress for a long-term strategy. Estimates of 
future population growth and associated changes in emissions, and a 
plan to ensure reasonable progress under these anticipated conditions, 
could be required by the program. Current visibility regulations 
require States to revise their long-term strategies every 3 years with 
respect to reasonably attributable impairment. A regional haze program 
should address long-term strategies for mitigating all types of 
visibility impairment, including regional haze impacts.
    Another consideration is the implementation of current statutory 
requirements. An EPA Report to Congress dealing with the effects of the 
1990 Act Amendments on visibility in Class I areas estimated that Class 
I areas from Maine to Georgia would see perceptible improvements in 
summer and winter visibility under expected implementation of the 
Amendments. The most significant improvements are expected for Class I 
areas along the Central and Southern portions of the Appalachian 
Mountains. The 1993 report indicates that modeled future improvements 
in annual average Eastern regional visibility are directly related to 
expected reductions of SO2 emissions under title IV of the Act 
(i.e., the acid rain program). Note, however, that current models are 
not reliable enough to estimate the extent of improvement in the number 
of clear and hazy days at specific locations.
    Question: How should regional haze regulations address the 
requirement for BART for sources that may reasonably be anticipated to 
contribute to regional haze?
    Rules for regional haze are required to address BART for any major 
source placed in operation between 1962 and 1977 that ``emits any air 
pollutant which may reasonably be anticipated to cause or contribute to 
any impairment of visibility'' in a mandatory Federal Class I area. The 
EPA's current visibility rules limit BART to major stationary sources 
whose contribution is ``reasonably attributable'' to impairment in a 
Federal Class I area. Recognizing that determinations of BART for 
regional haze involves contributions from multiple sources, EPA 
solicits comment on how technological controls, costs, the degree of 
improvement in visibility which may reasonably be anticipated, and 
other factors contained in section 169A(g)(2) should be considered.
    Section 169A(g)(2) defines BART as follows: ``* * * in determining 
best available retrofit technology, the State (or the Administrator in 
determining emission limitations which reflect such technology) shall 
take into consideration the costs of compliance, the energy and nonair 
quality environmental impacts of compliance, any existing pollution 
control technology in use at the source, the remaining useful life of 
the source, and the degree of improvement in visibility which may 
reasonably be anticipated to result from the use of such technology * * 
*.'' (42 U.S.C. 7491(g)(2).
    Under the existing visibility program, the BART process has 
involved extensive technical assessments to demonstrate that emissions 
from a specific major source contribute a specific amount of impairment 
at a specific Federal Class I area. The regional haze program should 
address whether the BART requirement would be interpreted differently 
for the purposes of remedying existing impairment due to the cumulative 
emissions from sources located across broad regions.
    One alternative interpretation could involve the identification of 
sources potentially subject to BART, development of emission rates 
determined to be equivalent to BART for key source categories, the 
estimation of total emission reductions that would be achieved if BART-
level emission rates are implemented, incorporation of these reductions 
into regional emission reduction targets, and implementation of 
programs by the States to achieve these emission reductions. Regional 
emission reduction targets for BART could be met through reductions 
from BART-eligible stationary sources, or the program could potentially 
allow an equivalent level of reductions through some other means, such 
as a trading program. Under such an approach, proposed emission 
reductions planned for attaining any new NAAQS will improve visibility 
conditions to some degree. Thus, program integration is needed to 
assess the extent to which strategies for attaining the NAAQS will help 
meet section 169A requirements for making reasonable progress and 
implementing BART.
    Question: What should be the process for FLM's and EPA involvement 
in reviewing SIP revisions and reasonable progress demonstrations?
    States are required to consult in person with the appropriate FLM's 
before holding a public hearing on any SIP revisions for visibility. 
The regional haze program, therefore, should define roles and 
responsibilities of FLM's, States, and EPA in the review of SIP 
revisions and reasonable progress demonstrations. It should include 
ways that input from FLM's and EPA can be incorporated early in program 
planning activities.
    Issue: Visibility SIP revisions due after 12 months--States will be 
required to revise their SIP's within 12 months of promulgation of 
regional haze regulations.
    The regional haze rules will need to identify the program elements 
to be addressed in these SIP's. Monitoring strategies, emissions 
inventories and tracking, emission limitations, schedules of 
compliance, and adequacy of personnel, funding, and authority for 
program implementation are all important areas for consideration. The 
EPA seeks input on other elements that should be included in visibility 
SIP's and how to coordinate regional haze program implementation with 
NAAQS implementation.
    Issue: Monitoring Program--Since 1987, EPA has supported the 
IMPROVE network in cooperation with the National Park Service, other 
FLM's, and State organizations. The IMPROVE network employs aerosol, 
optical (i.e., nephelometers and transmissometers) and scene (i.e., 35 
mm photography) measurements. Direct measurements are taken of fine 
particles and precursors that contribute to visibility impairment at 
more than 40 mandatory Federal Class I areas across the country. 
Aerosol measurements are taken twice a week

[[Page 65774]]

for PM-10 and fine particle masses and for key constituents of fine 
particles, such as sulfate, nitrate, organic and elemental carbon, soil 
dust, and several other elements. Measurements for specific aerosol 
constituents are used to calculate ``reconstructed'' aerosol light 
extinction by multiplying the mass for each constituent by its 
empirically-derived scattering and/or absorption efficiency. These 
reconstructed light extinction levels are cross-checked with 
nephelometer and/or transmissometer measurements. Knowledge of the main 
constituents of a site's light extinction ``budget'' is critical for 
source apportionment and control strategy development. These 
methodologies allow estimates of how proposed changes in atmospheric 
constituents would affect future visibility conditions.
    Currently, the IMPROVE monitoring protocols for aerosol, optical, 
and scene measurements are not included as Federal reference methods 
because visibility is not regulated under the NAAQS. The EPA is 
developing a visibility monitoring guidance document, however, that 
will identify important methods and procedures for effective aerosol, 
optical, and scene monitoring.
    Question: Will the current IMPROVE network be sufficient to 
determine reasonable progress for mandatory Federal Class I areas?
    States implementing a new regional haze program can benefit from 
the existing infrastructure of the IMPROVE network, established 
protocols, existing sites, and historical data available. The fact that 
monitoring equipment is located at only about a quarter of the 156 
mandatory Federal Class I areas, however, raises the issue of whether 
the current configuration is representative of all sites, and whether 
the network needs expansion. The GCVTC, in its recommendations on 
future technical needs, states that: ``The current IMPROVE monitoring 
network only measures aerosol samples twice a week and at only a few 
Federal Class I sites * * *. Consideration should be given to expanding 
the coverage or redeployment of resources in the IMPROVE network to 
enhance completeness of the data set, including on tribal lands. In 
addition, background surveillance sites could be established at 
intermediate locations between Federal Class I areas and large regional 
sources (metropolitan areas) to provide a better understanding of the 
intermediate course of atmospheric chemistry and transport. Monitoring 
should be maintained at existing sites in order to allow for long-term 
trend analysis.''
    As discussed above, visibility SIP submittals and State reasonable 
progress demonstrations likely will rely on monitored data from the 
IMPROVE network. Thus, it should be determined whether the existing 
geographic distribution of IMPROVE network sites is adequate for making 
future determinations of reasonable progress in all Federal Class I 
areas and for verifying models for predicting possible visibility 
effects of future air quality management strategies. In addition, the 
ability for the current cooperative arrangement between EPA, FLM's and 
the States for managing and funding the network in the future should be 
assessed.
2. Designations for New NAAQS and Regional Haze Planning Areas
    Under the current statutory requirements and EPA policy, EPA is 
required to designate areas as attainment, nonattainment, or 
unclassifiable after promulgation of a new or revised NAAQS. The 
designation process allows EPA to identify geographic regions where the 
public is subject to potential health risks, to alert the public to the 
existence of those areas, and to require States to establish control 
programs to mitigate those health risks.
    The EPA is giving advance notice that regional haze planning areas 
(to address Federal Class I areas) may need to be established for the 
purposes of conducting technical assessments and developing plans to 
abate haze on a regional basis. This is the approach to reducing haze 
recommended by the NRC, as well as the GCVTC. Because haze results from 
direct emissions of fine particles and fine particle and ozone 
precursors, the Subcommittee is considering whether regional haze 
planning areas should coincide with nonattainment areas or other types 
of control strategy areas established to reduce ozone and PM.
    Given that EPA will designate areas and may establish regional haze 
planning areas, there are several issues that must be resolved. These 
relate mainly to the timing of designations, the basis for designations 
(e.g., the use of monitoring or modeling data), the size of 
nonattainment areas, and the role of transport in the designations 
process. These requirements raise questions such as the following.
    Question: What are EPA's options in developing designation schemes 
for areas violating the new revised NAAQS?
    Question: Should there be differentiation in designations between 
areas where violations are occurring and the source areas contributing 
to the problem?
    Question: Should nonattainment status be changed to indicate only a 
public health risk or should nonattainment both indicate the public 
health risk and trigger control strategies?
    Other questions identified to date include the following.
    Question: What information should be used as a basis for 
designating areas and establishing regional haze planning areas, e.g., 
monitoring data, modeling data, other data, or combinations of 
monitoring, modeling, and other data?
    Question: If monitoring or modeling data are relied upon, will 
adequate information be available within the appropriate timeframe?
    Question: To what extent, if any, should the boundaries of 
nonattainment areas, control strategy areas and regional haze planning 
areas coincide or should there be separate areas for ozone, PM, and 
regional haze?
    Question: How can incentives be created to monitor air quality in 
order to gain a better scientific understanding of the pollutants and 
avoid disincentives when NAAQS violations are measured? How can 
incentives be created for private sectors to form monitoring 
partnerships with EPA and States?
3. Mechanisms to Address Regional Strategies
    Question: How do we develop or use existing institutional 
mechanisms to effectively implement control strategies incorporating 
multistate regionally--or nationally-applicable measures?
    Reviews of monitoring/modeling data suggest that violations of new 
ozone NAAQS in the center of the range described by the Clean Air 
Science Advisory Committee (CASAC) are likely to be more widespread 
than is the case with the current NAAQS. Further, data available at 
this time suggest that if a PM-2.5 NAAQS is established in the lower 
end of the range being considered, it too may result in a problem which 
is regional in scope. By its definition, regional haze is a regional 
problem. Areas that present the most concerns for visibility protection 
(i.e., Federal Class I areas such as national parks and wilderness 
areas) are often located at considerable distances from anthropogenic 
sources of visibility degradation.
    The likely regional scope of problems meeting new NAAQS or 
visibility goals implies a need for measures applied over large (e.g., 
multistate) geographical areas.
    Question: Should a framework for institutional mechanisms be 
identified

[[Page 65775]]

and developed for facilitating development and implementation of 
strategies to reduce regional transport of ozone, fine particles, and 
their precursors?
    Recently, several cooperative efforts have emerged to better 
understand and address regional problems. Some of these have been 
mandated, others are voluntary. Examples include NESCAUM, Mid-Atlantic 
Regional Air Management Association (MARAMA), Lake Michigan Air 
Directors Consortium (LADCO), OTC, Southeast States Air Regional 
Management (SESARM), OTAG, Western States Air Resources Council 
(WESTAR), GCVTC, State and Territorial Air Pollution Program 
Administrators/Association of Local Air Pollution Control Officials 
(STAPPA/ALAPCO) and the Environmental Commissioners of States 
organization (ECOS).
    Question: What attributes of existing multistate institutions have 
been successful or appear essential for assisting in the development 
and implementation of a regional strategy? Can or should multistate 
institutions be developed using one or more existing institutions as a 
starting point?
    To identify an appropriate institutional mechanism to facilitate 
State implementation of programs to meet several air quality goals 
which are regional in scope, it is first necessary to more specifically 
define what principles are appropriate for such a group. The following 
principles, developed by the National and Regional Strategies Work 
Group to guide their deliberations, are proposed for consideration.
    Principle: The institutional mechanism which is established should 
develop an operating protocol whereby participating States can reach 
agreement on regional measures to implement. The protocol would address 
such issues as, who gets to vote?; what constitutes consensus?; to what 
extent are consensus decisions binding?; what should be the role of the 
private sector?; what steps should be followed if there is no 
compliance with an agreement?
    Principle: The institutional mechanism should develop a means for 
summarizing and distributing information on the scientific basis, 
technical viability and capital/operating costs associated with 
measures under consideration. In addition, the institution should 
provide a means, along with the EPA, for facilitating distribution of 
consistent information regarding emissions, air quality, meteorological 
data and modeling results to member States.
    Question: When considering possible regional strategies, what 
limitations are imposed by State laws or other constraints? Are clear 
priority options or ``operating principles'' needed for any 
institutional mechanism which is formed to help implement regional 
control measures? The following principles serve as possible examples.
    Principle: Use the institutional mechanism as a means to establish 
positive incentives for upwind areas to reduce precursor emissions. 
Possible approaches to consider include: having downwind areas/sources 
defray some of the control costs at upwind locations in exchange for 
not having to implement the most costly controls in their area, use of 
performance goals rather than specific measures, and providing a 
``bonus credit'' for early implementation.
    Principle: Use the institutional mechanism as a means for fostering 
communication among States and the private sector involved with 
implementing measures. This goal envisions the mechanism as providing 
an information clearinghouse on what different States are doing and the 
appropriate contacts for further details. The institutional mechanism 
might also serve as the means for facilitating periodic meetings on 
various subjects related to implementing regional strategies in a 
coordinated fashion.
    Principle: Use the institutional mechanism as a means for promoting 
use of improved analytical tools and data bases as well as to promote 
use of consistent assumptions among the States which are implementing 
regional measures.
4. Integration of NAAQS and Regional Haze Implementation Programs
    Question: When and where does it make sense to develop and 
implement integrated criteria and policies for urban ozone, fine 
particles and regional haze control programs?; for regional ozone, fine 
particle and regional haze control programs?
    As discussed in the previous science section, the photochemical 
reactions involving VOC, NOX and sunlight which produce ozone also 
produce other secondary pollutants. The photochemical reactions can 
result in oxidation of SO2 and NOX to produce visibility-
reducing species which may be regarded as fine PM or as haze. This 
realization leads to the question of whether control of ozone, fine 
particles and haze can be optimized through consideration of all of 
them together in an integrated fashion rather than considering each 
separately. This issue considers first how to decide if integration is 
appropriate and second, if it is, then what integrated control 
strategies should be implemented to reduce the impact on public health 
and improve visibility caused by regional haze?
    Before key national/regional/multipollutant control strategies can 
be developed, a clear understanding of what integration of ozone, PM, 
and regional haze means to the implementation process must be 
established. For instance, if the goal is to minimize the burden on the 
regulated industry, then the outcome of the control strategy may look 
different from one with the goal of maximizing the risk reduction to 
public health and welfare. Will the knowledge and understanding of 
these approaches be understood and the technical tools needed to 
integrate the programs be available, or must new state-of-the-science 
and technical tools be developed?
    While the focus of control strategy integration centers around the 
ozone, PM and regional haze programs, some consideration of how other 
programs affect these programs will need to be assessed (i.e., acid 
rain, climate change, stratospheric ozone, ecosystem protection, 
toxics). A number of questions arise when considering the feasibility 
of an integrated strategy.
    Question: What should be the basis for designing control 
strategies?
    Question: Should integration utilize consistent or uniform modeling 
approaches to understanding long-range transport? What is the most 
practical way to accomplish this?
    Question: Is an atmospheric chemistry linkage needed between all 
the programs? Currently, efforts are under way for fine particles and 
ozone. There may be some SO2 chemistry included and limited toxics 
integration. Are these adequately characterized?
    Question: How should multipollutant integration fit into the 
development and initiation of control strategies and programs?
    Question: How can contributing sources be identified?
    Question: If equity between control of long-range transport and 
control of local generation of pollutants is important, how could it be 
defined?
    Question: What qualitative considerations can be made to provide 
assurance that control programs for ozone, PM, regional haze, toxics, 
acid deposition, etc., are integrated with one another?
    To identify an appropriate framework for implementing efficient 
programs that meet several air quality goals for pollutants which are 
regional in scope, it is first necessary to more specifically define 
what principles are appropriate. As indicated above, the following

[[Page 65776]]

principles are guiding the National and Regional Strategies Work Group 
deliberations and could provide an initial set for consideration:
    Principle: Pursue integrated control strategies for simultaneously 
reducing ambient concentrations of tropospheric ozone and fine PM if 
there are sufficient observation-based data to demonstrate both an 
environmental and economic benefit to integration.
    Principle: Emphasize performance-based control strategies in lieu 
of prescriptive command-and-control strategies.
    Principle: Develop controls that establish emission reduction 
responsibility based on the contribution to the problems, while also 
considering cost-effectiveness.
    Principle: Emphasize broad-scale control strategies for 
contributing sources where dictated by sound science.
    Principle: Focus on the interactions of the pollutants and the 
interactions between control strategies, identifying both positive and 
negative interactions.
    Principle: Integrate the implementation of the three programs 
(ozone, PM, and regional haze) to the greatest extent possible.
    Principle: Recognize that decisions need to be made based on 
scientific information that is improving and find institutional 
mechanisms to allow for mid-course corrections when significant new 
information is available.
5. Prevention of Significant Deterioration (PSD) of Air Quality and 
Nonattainment New Source Review (NSR)
    Protection of the NAAQS, including new and revised standards, is 
provided in part under Federal regulations requiring the 
preconstruction review of large new and modified stationary sources of 
air pollution, referred to as ``major stationary sources.'' As 
described below, the nature of the changes which EPA will be proposing 
to the implementation policies for the NAAQS for both ozone and PM will 
necessitate consideration of significant changes to these regulations 
commensurate with the types of issues already described in this ANPR.
    Two separate preconstruction review programs exist, based on the 
air quality attainment status of the proposed location of source 
construction. Major stationary sources locating in areas designated 
attainment or unclassifiable for a particular pollutant are subject to 
requirements for the PSD of air quality. Major stationary sources 
located in areas designated nonattainment for a particular pollutant 
must undergo review via nonattainment NSR requirements.
    Under the PSD program, a major stationary source is defined as one 
that emits or has the potential to emit 250 tons per year (tpy) or more 
of any air pollutant, except where a source is one in a category 
specifically listed as a 100 tpy major source category. In addition to 
the pollutant for which the source is major, the PSD preconstruction 
review applies to each regulated pollutant which the major source will 
have the potential to emit in significant amounts, as defined by EPA 
regulations. Sources required to undergo PSD review generally must 
demonstrate to the applicable permitting authority that proposed 
emissions increases will not cause or contribute to violations of the 
NAAQS or maximum allowable pollutant concentration increases (known as 
increments). Under certain circumstances, the source may also need to 
demonstrate that emissions will not have an adverse impact on air 
quality related values in Federal Class I areas. The air quality impact 
analyses associated with these demonstrations rely upon the use of both 
predicted (modeled) air quality and measured (ambient monitoring) data. 
The predictions of air quality using air dispersion models require the 
use of emissions data for the new or modified source and certain 
existing sources within the potential area of impact. Where adequate 
ambient data are not available, the permitting authority may require 
the PSD applicant to collect 1 year of ambient monitoring data. As 
described earlier in this ANPR, changes in the way which air quality 
assessments are made, considering how emissions, meteorological 
processes, atmospheric chemistry, and deposition occur over multiple 
spacial and temporal scales, will likely affect the way in which future 
PSD air quality impact analyses are carried out for ozone and PM.
    In addition, the PSD applicant must demonstrate that proposed 
emissions increases will be controlled through the use of best 
available control technology (BACT). The determination of BACT involves 
the selection of the most effective control technology for reducing 
emissions of a particular pollutant on a case-by-case basis, taking 
into consideration energy, environmental and economic impacts and other 
costs. Decisions for controlling PM, for example, could be affected by 
the particle size, as well as the chemical composition, of the PM 
proposed to be emitted. Moreover, changes to the requirements for 
applying BACT to individual sources may be needed to more adequately 
address the consideration of precursor contributions and atmospheric 
chemistry in selecting the best controls to provide the most effective 
ambient benefits for ozone and PM.
    Increments for PM were originally defined for total suspended 
particulate (TSP). The EPA later replaced those increments with PM-10 
increments following replacement of the TSP NAAQS with the PM-10 NAAQS. 
Should EPA adopt NAAQS for PM which include standards for both PM-10 
and fine particles, then EPA will need to consider how that will affect 
the current PM-10 increments. Increments for ozone have never been 
established because of the technical difficulty associated with 
predicting ambient concentration changes resulting from individual 
stationary sources of VOC.
    Under the nonattainment NSR regulations, ``major source'' is 
defined generally as any stationary source that emits, or has the 
potential to emit, in consideration of controls, 100 tpy or more of the 
nonattainment pollutant, except in specific cases where lower 
thresholds apply to more serious nonattainment classifications. The 
basic nonattainment NSR requirements for the construction or 
modification of major stationary sources in nonattainment areas and the 
ozone transport region include the requirement that the lowest 
achievable emission rate technology be installed, and that the 
increased emissions of the nonattainment pollutant from the proposed 
new major source or major modification be offset by actual emissions 
decreases of the same pollutant from one or more existing sources. The 
offsets may come from the same nonattainment area or another 
nonattainment area of equal or higher classification as long as the 
offsetting emissions contribute to the air quality problem in the area 
where the decrease is being credited. As with PSD, the NSR requirements 
for control technology application and offsets do not adequately 
account for precursor activities or for the complexities associated 
with atmospheric chemistry.
    Any revised ozone and PM NAAQS may suggest that existing 
implementing guidance, EPA's nonattainment NSR rules, and the States' 
nonattainment NSR programs will need to be reviewed and revised in 
various ways to address the integrated implementation approach being 
contemplated.
    The FACA Subcommittee and work groups will look into how the 
current PSD/NSR programs for ozone and PM-10 attainment, unclassifiable 
and nonattainment areas could be adapted

[[Page 65777]]

or modified. Some PSD/NSR questions that may consider include:
    Question: What types of mitigation procedures should be required of 
major new or modified sources that would contribute to violations of 
the revised NAAQS for ozone or PM, or to visibility impairment in 
Federal Class I areas?
    Question: Should PSD/NSR requirements reflect the potential for 
broad intra and interstate nonattainment areas, control areas, and 
regional haze planning areas that could result when addressing 
implementation under revised NAAQS for ozone and PM?
    Question: What approach should be developed for the treatment of 
ozone and fine particle precursors for PSD/NSR applicability purposes?
    Question: Should the PSD/NSR programs allow for precursor 
substitutions when environmentally beneficial to meet offset and 
control technology requirements?
    Question: How can availability, crediting, and location of 
emissions offsets be restructured under a more regionalized 
implementation strategy for PM?
6. Attainment Dates
    Areas designated nonattainment with respect to a primary NAAQS are, 
under the current statutory structure, required to achieve attainment 
as expeditiously as practicable, but no later than 5 years from the 
date the area was designated nonattainment. The EPA may extend this 
date up to an additional 5 years. This extension may be a full 5 years 
or any 1 year increment in between. Additionally, the Administrator may 
grant two 1-year extensions.
    With respect to a potential new secondary ozone NAAQS, areas 
designated nonattainment are required, under the current statutory 
structure, to achieve attainment of the secondary NAAQS as 
``expeditiously as practicable'' following designation. Secondary 
nonattainment areas are not bound to the same 10-year deadline as 
primary areas.
    Question: Given the preceding discussion, how should attainment 
dates for primary and secondary NAAQS be established?

B. Phase II Issues

    As discussed earlier in this notice, in Phase I, the FACA 
Subcommittee and work groups will address air quality management 
framework issues. The EPA plans to propose the resulting Phase I 
strategy in mid-1997. Phase II of the integrated implementation 
strategy will focus on more detailed control strategy development. The 
EPA plans to propose the Phase II strategy in mid-1998. The Phase II 
implementation issues include:

--Classifications of nonattainment areas;
--Control requirements (e.g., reasonably available control measures 
including reasonably available control technology);
--Economic incentive programs;
--State implementation plan requirements;
--Overall control program integration;
--Measures of progress; and,
--Institutional processes.
All of these issues will be discussed in greater detail at a later 
date. Interested readers are directed to EPA's TTN and WWW site for an 
up-to-date status of the work groups and Subcommittee deliberations on 
these issues.

V. Administrative Requirements

A. Executive Order 12866

    Under Executive Order 12866, 58 FR 51735 (October 4, 1993), the 
Administrator must determine whether the regulatory action is 
significant and therefore subject to the Office of Management and 
Budget (OMB) review and the requirements of the Executive Order. The 
Order defines significant regulatory action as one that is likely to 
result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, productivity, 
competition, jobs, the environment, public health or safety or State, 
local, or tribal governments or communities;
    (2) create a serious inconsistency or otherwise interfere with an 
action taken or planned by another Agency;
    (3) materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that this ANPR announces a significant regulatory action, 
and as such, will be submitted to OMB for review. Any written comments 
from OMB to EPA, any written EPA responses to those comments, and any 
changes made in response to OMB suggestions or recommendations will be 
included in the docket. The docket is available for public inspection 
at the EPA's Air and Radiation Docket and Information Center, which is 
listed in the ADDRESSES section of this notice.

B. Miscellaneous

    Requirements under the Unfunded Mandates Act of 1995, the Paperwork 
Reduction Act, and the Regulatory Flexibility Act will be addressed if 
and when the Agency issues a proposed rule based on the comments 
received on this ANPR.

List of Subjects in 40 CFR Part 51

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Carbon monoxide, Nitrogen dioxide, Ozone, 
Particulate matter, Sulfur oxides, Volatile organic compounds.

    Dated: December 4, 1996.
Carol M. Browner,
Administrator.

Appendix

Definitions

    Annual sulfate conversion: Although significant gas phase 
transformation of sulfur dioxide occurs, aqueous phase oxidation is 
believed to be responsible for the majority of annual sulfate 
conversion in the Eastern U.S.
    ``Best'' and ``worst'' days: Can be defined as the average of 
the 20 percent best and worst days, respectively, as measured in 
terms of total light extinction.
    Chemical sinks: Termination compounds that essentially remove 
other compounds (e.g., nitric acid, hydrogen and organic peroxides). 
Some ``sinks'' can eventually break down and reform precursor 
compounds (e.g., peroxy acetyl nitrate, PAN).
    Deciview: Derived from the light extinction coefficient and 
describes changes in uniform atmospheric extinction that can be 
perceived by a human observer. It is designed to be linear with 
respect to perceived visual changes over its entire range in a way 
that is analogous to the decibel scale for sound. A 1-deciview 
change is roughly equivalent to a 10 percent change in visibility.
    Improve: A federally-administered visibility monitoring network 
for Federal Class I areas in several States that failed to submit 
SIP's containing monitoring strategies as required in the 1980 
visibility regulations. Intermediates: Include the short-lived 
radicals (hydroxyl, hydro-, and organic-peroxy) which perform many 
of the important atmospheric oxidation reactions.
    Mandatory Federal Class I Areas: Areas designated as mandatory 
Federal Class I areas are those national parks exceeding 6000 acres, 
wilderness areas and memorial parks exceeding 5000 areas, and all 
international parks which were in existence on August 7, 1977.
    Precursors: Compounds which contribute or lead to the formation 
of a secondary pollutant. For example, NOx and VOC are ozone 
precursors.
    Reasonably attributable: Visibility impairment, as defined in 40 
CFR 51.301, that is ``attributable by visual observation or any 
other technique the State deems appropriate.'' It includes impacts 
to mandatory Federal Class I areas caused by

[[Page 65778]]

smoke, plumes or layered hazes from a single source or group of 
sources.
    Visibility regulations: See 45 FR 80084 (December 2, 1980) 
(codified at 40 CFR 51.300-307).
    VOC species: Most low molecular weight VOC species (which are 
most prevalent in ambient air) are not expected to contribute 
significantly to secondary aerosol formation. Certain aromatics, and 
higher molecular weight alkanes and alkenes (>6 carbons) are 
believed to be the major contributors to secondary organic aerosol 
formation.

References

    1. Appleton, E.L., ``A Cross-Media Approach to Saving the 
Chesapeake Bay,'' Environ. Sci. Technol., 1995, 29, 550A-555A.
    2. Dennis, R.L., Personal Communication, 1996.
    3. EPA, 1996, ``PM Criteria Document.''
    4. GCVTC, ``Report of the Grand Canyon Visibility Transport 
Commission'' to the U.S. EPA, June 1996.
    5. NESCAUM, ``Preview of 1994 Ozone Precursor Concentrations in 
the Northeastern U.S.,'' 1995 Northeast States for Coordinated Air 
Use Management, Boston, MA.
    6. NRC, ``Rethinking the Ozone Problem in Urban and Regional Air 
Pollution,'' National Academy Press, 1991.
    7. NRC, ``Protecting Visibility in National Parks and Wilderness 
Areas,'' National Academy Press, 1993.
    8. Rao, 1996, Personal Communication, 1996.
    9. Rao et al., ``Dealing with the ozone nonattainment problem in 
the Eastern United States'', 1996.
    10. Rao, S.T.E. Zalewsky and I.G. Zurbenko, ``Determining 
Temporal and Spatial Variations in Ozone Air Quality,'' J. Air & 
Waste Management Association; 1995,45, 57-61.
    11. Trijonis, J. et al., ``Report 24--Visibility: Existing and 
Historical Conditions--Causes and Effects,'' from Acidic Deposition: 
State of Science and Technology,'' Volume III, National Acid 
Precipitation Assessment Program, 1990.
    12. U.S. Senate, Committee on Environment and Public Works, ``A 
Legislative History of the Clean Air Act Amendments of 1990,'' 
Volume IV, p. 6093.

[FR Doc. 96-31343 Filed 12-12-96; 8:45 am]
BILLING CODE 6560-50-P