[Federal Register Volume 63, Number 236 (Wednesday, December 9, 1998)]
[Proposed Rules]
[Pages 67818-67834]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-32571]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58

[FRL-6198-6]
RIN 2060-AH92


Air Quality Index Reporting

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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

SUMMARY: EPA proposes to change the uniform air quality index used by 
States for daily air quality reporting to the general public in 
accordance with section 319 of the Clean Air Act (Act). These proposed 
changes include the addition of the following elements: a new category 
described as ``unhealthy for sensitive groups,'' new breakpoints for 
the ozone (O3) sub-index in terms of 8-hour average 
O3 concentrations, a new sub-index for fine particulate 
matter (PM2.5), and conforming changes to the sub-indices 
for inhalable particulate matter (PM10), carbon monoxide 
(CO), and sulfur dioxide (SO2). These proposed changes 
reflect the revisions to the health-based primary national ambient air 
quality standards (NAAQS) for O3 and particulate matter (PM) 
published in the Federal Register on July 18, 1997. This document 
discusses the development of related informational materials on 
pollutant-specific health effects and sensitive groups and on 
precautionary actions that can be taken by individuals to reduce 
exposures of concern. This document also discusses the 
interrelationship between the uniform air quality index and other 
programs that provide air quality information and related health 
information to the general public, including State and local real-time 
air quality data mapping and community action programs.

DATES: Written comments on this proposed rule must be received by 
January 25, 1999.

ADDRESSES: Submit comments (in duplicate if possible) on the proposed 
rule to: Air and Radiation Docket and Information Center (6102), Attn: 
Docket No. A-98-20, Environmental Protection Agency, 401 M St., SW, 
Washington, DC 20460.

FOR FURTHER INFORMATION CONTACT: Terence Fitz-Simons, MD-14, Office of 
Air Quality Planning and Standards, EPA, Research Triangle Park, NC 
27711, telephone (919) 541-0889, e-mail fitz-
[email protected]. For health effects information contact 
Susan Lyon Stone, MD-15, Office of Air Quality Planning and Standards, 
EPA,

[[Page 67819]]

Research Triangle Park, NC 27711, telephone (919) 541-1146, e-mail 
[email protected].

SUPPLEMENTARY INFORMATION: In compliance with President Clinton's June 
1, 1998 Executive Memorandum on Plain Language in government writing, 
this package is written using plain language. Thus, the use of ``we'' 
or ``us'' in this package refers to EPA. The use of ``you'' refers to 
the reader and may include industry, State and local agencies, 
environmental groups and other interested individuals.

Docket

    Docket No. A-98-20, containing information relating to the EPA's 
revision of the uniform air quality index, is available for public 
inspection in the Air and Radiation Docket and Information Center of 
the Environmental Protection Agency, 401 M St. SW, room M-1500, 
Washington, DC. The docket may be inspected between 8:00 a.m. and 4:00 
p.m., Monday through Friday, excluding holidays. A reasonable fee may 
be charged for copying.

Availability of Related Information

    Certain documents are available from the U.S. Department of 
Commerce, National Technical Information Service, 5285 Port Royal Road, 
Springfield, VA 22161. Available documents include:
    (1) The Review of the National Ambient Air Quality Standards for 
Ozone: Assessment of Scientific and Technical Information (``Staff 
Paper'')(EPA-452/R-96-007, June 1996, NTIS # PB-96-203435, $67.00 paper 
copy and $21.50 microfiche). (Add a $3.00 handling charge per order.)
    (2) Review of the National Ambient Air Quality Standards for 
Particulate Matter: Policy Assessment of Scientific and Technical 
Information (``Staff Paper'') (EPA-452/R-96-013, July 1996, NTIS #PB-
97-115406, $47.00 paper copy and $19.50 microfiche). (Add a $3.00 
handling charge per order.)
    The following document will be available in January 1999 from the 
National Center for Environmental Publications and Information (NCEPI). 
Requests for this publication can be mailed to: U.S. Environmental 
Protection Agency, NCEPI, P.O. Box 42419, Cincinnati, OH, 45242. Your 
request may also be phoned in to NCEPI at 1-800-490-9198 or faxed to 
513-489-8695.
    (1) Community Action Programs: Blueprint for Program Design (EPA 
420-R-98-003).

Table of Contents

I. Background
    A. What are the Legislative Requirements?
    B. What is the History of the Air Quality Index?
    C. What Programs are Related to the PSI?
    1. Ozone and Particulate Matter NAAQS Revisions
    2. Real-Time Data Reporting Initiative (Ozone Mapping Project)
    3. Community Action Programs
II. Rationale for Proposed Revisions
    A. What was the Early Input from State/local Agencies?
    B. Staff Draft Revisions to PSI Sub-index for Ozone
    1. Availability for Use in the 1998 Ozone Season
    2. What were the Staff Draft Revisions?
    3. Related Informational Materials
    4. What was the Feedback on the Staff Draft?
    C. What is the Basis for the Proposed Revisions?
    1. What are the Proposed General Changes?
    2. What are the Proposed Changes to the Sub-Indices?
    3. What are the Changes to Related Informational Materials?
III. Regulatory and Environmental Impact Analyses
    A. Executive Order 12866: OMB Review of ``Significant Actions''
    B. Regulatory Flexibility Analysis/Small Business Regulatory 
Enforcement Fairness Act
    C. Unfunded Mandates Reform Act
    D. Paperwork Reduction Act
    E. Executive Order 13045: Children's Health
    F. Executive Order 12848: Environmental Justice
    G. Executive Order 12875: Enhancing Intergovernmental 
Partnerships
    H. Executive Order 13084: Consultation and Coordination with 
Indian Tribal Governments
    I. National Technology Transfer and Advancement Act
IV. References

I. Background

A. What Are the Legislative Requirements?

    Section 319 of the Act governs the establishment of uniform air 
quality index for reporting of air quality. This section directs the 
Administrator to ``promulgate regulations establishing an air quality 
monitoring system throughout the United States which utilizes uniform 
air quality monitoring criteria and methodology and measures such air 
quality according to a uniform air quality index'' and ``provides for 
daily analysis and reporting of air quality based upon such uniform air 
quality index* * *''.

B. What Is the History of the Air Quality Index?

    In 1976, we established a nationally uniform air quality index 
(AQI), called the Pollutant Standard Index (PSI), for use by State and 
local agencies on a voluntary basis (41 FR 37660). This uniform index 
was established in light of a study conducted by EPA and the 
President's Council on Environmental Quality (CEQ, 1976). This study 
found that the 55 urban areas in the U.S. and Canada reporting an index 
of air quality used 14 different indices, in conjunction with different 
cautionary messages, such that in essence 55 different indices were 
being used to report air quality. This diversity of indices sent a 
confusing message about air quality to the public. Based in part on 
this study, we developed an index to meet the needs of State and local 
agencies that has the following advantages: it sends a clear and 
consistent message to the public by providing nationally uniform 
information on air quality; it is keyed to the NAAQS and the 
significant harm level (SHL) 1 which have a scientific basis 
relating air quality and public health; it is simple and easily 
understood by the public; it provides a basis for accommodating changes 
to the NAAQS; and it can be forecasted to provide advance information 
on air quality.
---------------------------------------------------------------------------

    \1\ Significant harm levels are those ambient concentrations of 
air pollutants that present an imminent and substantial endangerment 
to public health or welfare, or to the environment, as established 
in 40 CFR part 51.151.
---------------------------------------------------------------------------

    The PSI, which is also commonly referred to by some State and local 
agencies as the AQI, includes sub-indices for O3, PM, CO, 
SO2, and nitrogen oxide (NO2), which relate 
ambient pollutant concentrations to index values on a scale from 0 
through 500. This represents a very broad range of air quality, from 
pristine air to air pollution levels that present imminent and 
substantial endangerment to the public. The index is normalized across 
pollutants by defining an index value of 100 as the numerical level of 
the primary NAAQS for each pollutant and an index value of 500 as the 
SHL.2 Such index values serve to divide the index into 
categories, with each category being

[[Page 67820]]

identified by a simple informative descriptor. The descriptors are 
intended to convey to the public information about how air quality 
within each category relates to public health, with increasing public 
health concerns being conveyed as the categories range to the upper end 
of the scale. Additional information about the general health effects 
associated with each category, and precautions that sensitive groups 
and the general public should take to avoid exposures of concern, has 
been made available through an informational booklet, updated as 
appropriate, that also presents and explains the PSI (EPA, 1994).
---------------------------------------------------------------------------

    \2\ Intermediate index values of 200, 300, and 400 were defined 
and are the basis for the Alert, Warning, and Emergency episode 
levels included in 40 CFR part 51, appendix L, as part of the 
Prevention of Air Pollution Emergency Episodes program. This program 
requires specified areas to have contingency plans in place and to 
implement these plans during episodes when high levels of air 
pollution, approaching the SHL, are in danger of being reached. 
Changes to this emergency episode program will be proposed in the 
near future.
    Below an index value of 100, an intermediate value of 50 was 
defined either as the level of the annual standard if an annual 
standard has been established (for PM10 and 
SO2), or as a concentration equal to one-half the value 
of the short-term standard used to define an index value of 100 (for 
O3 and CO). Inhalable particulate matter, 
PM10, refers to particles with an aerodynamic diameter 
less than or equal to a nominal 10 micrometers.
---------------------------------------------------------------------------

    In 1979, we made changes to the PSI, in part to reflect revisions 
to the NAAQS for O3, and to establish requirements for PSI 
reporting (44 FR 27598). The requirement for State and local agencies 
to report the PSI appears in 40 CFR part 58.50, and the specific 
requirements (e.g., what to report, how to report, reporting frequency, 
calculations) are in appendix G to 40 CFR part 58.

C. What Programs Are Related to the PSI?

    Historically, State and local agencies have used primarily the PSI, 
or other AQIs, to provide general information to the public about air 
quality and its relationship to public health. In recent years, many 
States and local agencies, as well as EPA, have been developing new and 
innovative programs and initiatives to provide more information to the 
public, in a more timely way. These initiatives, including real-time 
data reporting through the Ozone Mapping Project and community action 
programs, can serve to provide useful, up-to-date, and timely 
information to the public about air pollution and its effects. Such 
information will help individuals take actions to avoid or reduce 
exposures of concern and can encourage the public to take actions that 
will reduce air pollution on days when levels are projected to be in 
air quality categories of concern to local communities. Thus, these 
programs are significantly broadening the ways in which State and local 
agencies can meet the nationally uniform AQI reporting requirements, 
and are contributing to State and local efforts to provide community 
health protection and to attain or maintain compliance with the NAAQS. 
We and State and local agencies recognize that these programs are 
interrelated with AQI reporting and with the information on the effects 
of air pollution on public health that is generated through the 
periodic review, and revision when appropriate, of the NAAQS.
    The most recent revisions to the O3 and PM NAAQS, the 
Ozone Mapping Project, and community action programs are discussed 
briefly below. In light of the interrelationships among these programs, 
we have developed the revisions to the uniform AQI being proposed today 
with the goal of creating a revised AQI that can effectively serve as a 
nationally uniform link across these programs. In so doing, we intend 
to support and encourage State and local participation in real-time 
data reporting initiatives and the development and implementation of 
community action programs that serve public education and health 
protection goals.
1. Ozone and Particulate Matter NAAQS Revisions
    On July 18, 1997, we revised the primary NAAQS for O3 
and PM based on a thorough review of the scientific evidence linking 
exposures to ambient concentrations of these pollutants to adverse 
health effects at levels allowed by the previous NAAQS. In particular, 
we replaced the 1-hour O3 NAAQS with an 8-hour O3 
NAAQS and supplemented the PM NAAQS with 24-hour and annual standards 
for fine particulate matter (measured as PM2.5 
3). These revisions provide the basis for changes to the PSI 
to maintain the relationship between an index value of 100 and the 
level of the NAAQS, as well as to establish the relationships between 
ambient concentrations of these pollutants and index values across the 
full scale of index values from 0 to 500.
---------------------------------------------------------------------------

    \3\ PM2.5 refers to particles with an aerodynamic 
diameter less than or equal to a nominal 2.5 micrometers.
---------------------------------------------------------------------------

    In addition, as a result of the reviews of the scientific 
information upon which the O3 and PM NAAQS are based, an 
expanded understanding emerged as to the nature of the relationships 
between exposure to ambient concentrations of these pollutants and the 
health effects likely to be experienced, especially near the level of 
the NAAQS. We and the Clean Air Scientific Advisory Committee (CASAC) 
4 recognized that for these pollutants there are no 
discernible thresholds below which health effects are not likely to 
occur in the most sensitive individuals, but rather there is a 
continuum of effects potentially extending down to background levels. 
As ambient concentrations increase, the proportion of individuals 
likely to experience effects and the seriousness of the health effects 
increase. Thus, the standards are not risk free. While the standards 
protect public health with an adequate margin of safety, in accordance 
with sections 108 and 109 of the Act, including the health of sensitive 
groups, exposures to ambient concentrations just below the numerical 
level of the standards may result in exposures of concern for the most 
sensitive individuals. Conversely, exposures to ambient concentrations 
just above the numerical level of the standards are not likely to 
result in exposures of concern for most healthy people. This expanded 
understanding is reflected in the new forms of the standards, which 
allow for multiple days above the numerical level of the standards.
---------------------------------------------------------------------------

    \4\ CASAC is a scientific advisory committee established under 
the Act to review the scientific criteria and standards and to 
advise the Administrator on revision of the NAAQS, as appropriate.
---------------------------------------------------------------------------

    These understandings were reflected in CASAC's advice to the 
Administrator during the O3 NAAQS review, urging expansion 
of the public health advisory system (i.e., a uniform AQI) and 
communication to the public of the nonthreshold nature of the health 
effects. More specifically, a number of CASAC panel members recommended 
``that an expanded air pollution warning system be initiated so that 
sensitive individuals can take appropriate `exposure avoidance' 
behavior'' (Wolff, 1995). Consistent with this advice, in the preamble 
to the proposed revisions to the O3 NAAQS (61 FR 65733-4), 
the Administrator requested comment on the usefulness of providing 
specific health effects information when ambient concentrations are 
around the numerical level of the standard, the appropriateness of 
using the PSI to convey such information to the public, the possible 
addition of two new PSI categories (one just above and one just below 
the numerical level of the standard) and associated descriptors and 
levels, as well as related health effects and cautionary statements.
    Broad support for modifying the PSI was received in public comments 
on this aspect of the O3 NAAQS proposal, as discussed in the 
final rule establishing revisions to the O3 NAAQS (62 FR 
38873-4). Commenters overwhelmingly endorsed expanding the use of the 
PSI for various reasons, while many expressed concern with the possible 
category descriptors suggested in the proposal (i.e., ``moderately 
good'' and ``moderately unhealthful''). Many commenters felt that an 
expanded PSI could help particularly sensitive people take action to 
minimize their exposures, and that the PSI could be combined with 
community action programs to reduce ambient concentrations when the 
numerical level of the standard was forecasted to be exceeded. Some 
commenters endorsed increasing the

[[Page 67821]]

specificity of health and cautionary statements related to the PSI 
categories. Commenters from State and local agencies encouraged us to 
develop any approaches to revising the PSI in consultation with them, 
specifically in the areas of sharing real-time monitoring data, risk 
communication with the public, and coordination of a national program.
2. Real-time Data Reporting Initiative (Ozone Mapping Project)
    The Ozone Mapping Project is part of EPA's Environmental Monitoring 
for Public Access and Community Tracking (EMPACT) initiative--a new 
approach to providing timely environmental information to communities. 
It is a cooperative effort of the EPA, State and local air pollution 
control agencies, and regional organizations including the Mid-Atlantic 
Regional Air Management Association (MARAMA), the Northeast States for 
Coordinated Air Use Management (NESCAUM), the northeast Ozone Transport 
Commission (OTC), and the Lake Michigan Air Directors Consortium 
(LADCO). During the summer of 1998, EPA's Office of Air Quality 
Planning and Standards assumed coordination of the project.
    The Ozone Map provides simple and timely information about ground-
level O3. During the 1998 O3 season it was 
available on EPA's AIRNOW web site (http://www.epa.gov/airnow) and on 
some local television and news reports. It is an animated contour map 
that shows concentrations of O3, in categories ranging from 
good to moderate to varying degrees of unhealthy, based on PSI values, 
as it develops across the eastern U.S. It was created from real-time, 
hourly O3 data provided by a network of more than 400 air 
monitoring stations from South Carolina to Wisconsin and Maine. When 
accessed on a computer, cautionary statements for each category could 
be displayed by running a cursor over the legend. Also available on the 
AIRNOW web site were still maps of maximum values and forecasted 
values, and archived animated maps.
    Along with the Ozone Map, the AIRNOW web site contains information 
about O3 health effects in the ``Health Facts'' section, and 
emission reduction activities in the ``What You Can Do'' section. It 
also provides links to real-time data, and community action program web 
sites, that are maintained by State and local agencies around the 
country. The goals of the web site are to: (1) Provide real-time air 
pollution data in an understandable, visual format, (2) provide 
information about the public health and environmental effects of air 
pollution, and (3) provide the public with information about ways in 
which they can protect their health and actions they can take to reduce 
pollution.
3. Community Action Programs
    The implementation of community action programs (also referred to 
as episodic emission control programs) is becoming increasingly popular 
across the country as an innovative approach used to reduce emissions 
of O3 precursors, CO, and PM. Motivation for implementation 
of this type of program often stems from local government and business 
concerns about the NAAQS attainment status of the area and the 
restrictions, additional controls, and costs associated with being 
classified as a nonattainment area. Many areas are also motivated by 
public health concerns and believe that increasing the amount of air 
quality information available to sensitive populations raises awareness 
and results in significant health benefits. Specific goals which are 
usually associated with community action programs include: (1) Educate 
the public and enhance protection of public health; (2) attain or 
maintain NAAQS attainment status and the associated economic benefits; 
(3) meet specific emission reduction targets; and (4) manage/reduce 
traffic congestion.
    Community action programs are usually voluntary and generally 
provide multiple steps that the public, business, and industry can take 
to reduce emissions when higher levels of air pollution are forecast to 
occur, including in particular transportation-related measures such as 
trip reduction, postponement of certain activities such as vehicle 
refueling, and maintenance of cars. The programs emphasize educating 
the public about the impact of individual activities on local air 
quality and the basics of air pollution. The educational component of 
these programs also helps to create a strong link between environmental 
goals and associated public health benefits.
    Most of these programs are based on the categories of the PSI and 
make use of the PSI descriptors and related health effects and 
cautionary statements on action days. By linking action days to the 
PSI, local control programs hope to alter individual behavior to reduce 
emissions and to reduce exposures to the population. In addition to 
reduced pollutant exposure of the general population due to improved 
air quality, there are other health benefits directly associated with 
community action programs that can be enhanced by linkage to the PSI. 
Different population groups are more sensitive to the harmful effects 
of the different air pollutants included in the PSI, and the revisions 
to the PSI proposed today, together with related informational 
materials, will significantly improve the effectiveness of 
communications with these groups. Public education or programs directly 
targeting these groups may provide the most significant benefits of a 
community action program. Forecasting days with elevated pollution 
levels, and then communicating effectively about air quality and 
associated health effects, may help these groups selectively limit 
their outdoor activities and, therefore, limit their potential for 
exposures of concern.
    We are committed to providing States and local agencies with 
support in their efforts to meet air quality standards, to inform the 
public about air quality, and to educate the public about the impacts 
of air pollution. The revisions to the PSI being proposed today have as 
a goal the creation of a revised PSI that can effectively serve as a 
nationally uniform link across the range of programs (e.g., real-time 
data reporting initiatives, community action programs) that have these 
functions.
    In support of community action programs, we have developed 
informational materials related to the PSI, including the health 
effects and cautionary statements associated with each category and 
more detailed health effects information (see section II.B.3), 
available on the AIRNOW web site, that State and local agencies may use 
to enhance their community action programs. Focusing on transportation 
measures that are often a major component of community action programs, 
EPA's Office of Mobile Sources (OMS) has developed a report entitled, 
``Community Action Programs: Blueprint for Program Design.'' This 
document describes the major steps needed to put together a successful 
episodic control program and provides criteria that State and local 
agencies can use to examine and evaluate their own programs. The report 
will be available in January 1999 from NCEPI (See Availability of 
Related Information).

II. Rationale for Proposed Revisions

    In developing the revisions to the PSI that are being proposed 
today, we sought extensive input from State, local agencies, and from 
the public. As discussed below, we sponsored a workshop with State and 
local agencies, participated in numerous meetings, prepared and made 
available a staff draft revision to the PSI sub-index for O3 
for use during the 1998 O3 season, and conducted several 
focus groups to obtain public input on the effectiveness

[[Page 67822]]

of draft revisions to the PSI and related O3 maps and 
informational materials.

A. What Was the Early Input From State/local Agencies?

    In January 1998, we conducted a workshop for State and local air 
pollution control agencies on the PSI and related programs. The 
objectives of the Workshop were: (1) To give State/local agencies a 
preview and opportunity for input on anticipated revisions to the PSI, 
with particular focus on the O3 sub-index; (2) to provide 
information and generate discussion regarding the expansion of the 
Ozone Mapping Project and air quality forecasting approaches; (3) to 
share information about State/local real-time data reporting and Ozone 
Action Day programs (community action programs); and (4) to explore 
cross-cutting issues focusing on how these tools to facilitate 
communication (i.e., the PSI, Ozone Maps, forecasting) can best be 
linked to State/local programs. The Workshop provided a forum for broad 
discussion of these topics, among the participants, with many different 
points of view expressed.
    With regard to revisions to the PSI, broad consensus seemed to 
exist on the key issues of maintaining simplicity in the structure of 
the PSI and of providing up-to-date, consistent information relating 
air quality and public health. More specifically, it was the consensus 
view that the PSI should be kept as simple as possible, while being 
consistent with the expanded health information that emerged from the 
recently completed review of the O3 and PM NAAQS. The 
creation of two possible new categories (i.e., one just above and one 
just below the numerical level of the standard), as described in the 
O3 NAAQS proposal (61 FR 65733-4) and final decision (62 FR 
38873-4) notices, seemed to evoke negative reactions from most 
participants for varying reasons (e.g., too complex, too much 
information, too difficult to forecast in the narrow ranges suggested). 
Most participants favored creation of a new category above the 
numerical level of the standard (i.e., dividing the current 
``unhealthful'' category into two categories) considering both the 
expanded health information and linkages to community action programs. 
Creation of a new category below the level of the standard (i.e., 
dividing the current ``moderate'' category into two categories) was 
less generally supported--some felt that a new category just below the 
level of the standard was important for communicating risks and 
appropriate cautions, whereas many seemed to feel it was an unnecessary 
complication that could be confusing to the public.
    The Workshop discussion also produced consensus among the 
participants that any revisions to the descriptors used for PSI 
categories above the numerical level of the NAAQS should maintain the 
root word ``health'' rather than more neutral air quality descriptors 
(e.g., unsatisfactory). The Workshop participants generally preferred 
the use of the plain English word ``unhealthy'' to the currently used 
word ``unhealthful.''
    The Workshop participants generally encouraged us to revise the 
calculation methods for the PSI to be consistent with the conventions 
used in defining the NAAQS. More specifically, the participants 
supported changing the conventions for rounding numbers in calculating 
the PSI to be consistent with the rounding conventions used for the 
NAAQS. This revision would avoid situations where a health advisory 
could be issued that describes the air as unhealthy, when in fact the 
numerical level of the standard has not been exceeded.
    With regard to forecasting air quality and associated PSI values, 
Workshop participants generally recognized that for standards that have 
an averaging period longer than 1 hour (e.g., the 8-hour O3 
NAAQS), forecasting becomes increasingly important. Such forecasts can 
help people plan to avoid exposures of concern and can provide a basis 
for providing advance public notice of community action programs. There 
was strong support for us to prepare guidance on air quality 
forecasting, especially on using hourly O3 concentrations as 
predictors for 8-hour averages.
    The Workshop participants expressed strong support in general for 
enhancements to the Ozone Mapping Project, including real-time data 
reporting and forecasting. The selection of colors to be associated 
with the PSI categories depicted on the maps was the subject of much 
discussion. While there was broad recognition of the importance of 
using colors with such air quality maps, different views were expressed 
as to which colors should be associated with specific categories. For 
example, some participants from areas that had already developed or 
were developing community action programs expressed the view that the 
use of the color red on the map should be used for the category that 
triggers their programs' ``code red'' days. However, different programs 
have or intend to use different PSI index values to trigger action 
days, depending on the general level of air quality in the area and the 
objectives of the action day program in that area.
    In summary, Workshop participants encouraged us to develop 
revisions to the PSI with immediate emphasis on a revised sub-index for 
O3, reflecting the 8-hour O3 NAAQS. Many 
participants expressed an interest in using such a revised index during 
the 1998 O3 season. The participants also encouraged us to 
prepare additional information, including appropriate cautionary 
statements that could be used in conjunction with reporting a revised 
O3 sub-index and more in-depth information on O3 
health effects to help meet the educational goals of community action 
programs.
    Following the Workshop, we continued coordination with State and 
local air agencies and associations as part of the process of 
developing draft revisions to the PSI, particularly the O3 
sub-index, and related informational materials. Some of the agencies 
and associations that participated in meetings and discussions with us 
were the State and Territorial Air Pollution Program Administrators and 
the Association of Local Air Pollution Control Officials (STAPPA/
ALAPCO), the OTC, NESCAUM, MARAMA, the California Air Resources Board, 
the California Air Pollution Control Officers Association (CAPCOA), and 
the South Coast Air Quality Management District. While different points 
of view were expressed, all of these discussions reflected the 
importance of having a nationally uniform advisory system to present 
consistent health effects information that is related to air quality 
levels. These discussions helped shape the preparation of a staff draft 
PSI sub-index for O3, related O3-specific 
cautionary statements, and a draft booklet on O3 health 
effects, ``SMOG--Who Does It Hurt?''.

B. Staff Draft Revisions to PSI Sub-index for Ozone

1. Availability for Use in the 1998 Ozone Season
    Building on health effects information from the review of the 
O3 and PM standards, comments received on the O3 
NAAQS proposal, and input from State, local agencies, and associations, 
EPA staff prepared draft revisions to the PSI sub-index for 
O3. Recognizing that some State and local agencies wanted to 
use a sub-index based on the new 8-hour O3 NAAQS for the 
1998 O3 season, in early March we made the draft revised 
O3 sub-index available through our AIRNOW web site and 
through appropriate organizations across the nation. The availability 
of this revised

[[Page 67823]]

O3 sub-index made possible uniform reporting of the PSI 
during the 1998 O3 season based on the 8-hour O3 
NAAQS for those agencies that chose to do so.5 The draft 
sub-index categories, descriptors, and related O3 
concentrations, together with related cautionary statements, were the 
basis for the 1998 O3 maps produced by the Ozone Mapping 
Project. The draft O3 sub-index also provided a link to the 
8-hour O3 standard for use in O3 action programs 
around the country.
---------------------------------------------------------------------------

    \5\ For the 1998 O3 season, State and local air 
agencies could use either the staff draft revised O3 sub-
index based on the 8-hour O3 standard, or the PSI based 
on the 1-hour O3 standard.
---------------------------------------------------------------------------

2. What Were the Staff Draft Revisions?
    Draft revisions to the PSI and the O3 sub-index, 
together with new O3 specific cautionary statements, were 
based on the expanded understanding of O3 health effects 
gained during the review of the O3 NAAQS, comments received 
on the O3 NAAQS proposal and subsequent input from State and 
local agencies, and consideration of the implications of the draft 
revisions for the pollutants other than O3 that are included 
in the PSI.
    The staff draft O3 sub-index reflected general changes 
to the structure of the PSI as well as specific changes to reflect the 
new 8-hour O3 NAAQS. In particular, the primary change to 
the structure of the PSI was to divide the ``unhealthful'' category 
(PSI values of 101 to 200) into two categories, ``unhealthy for 
sensitive groups'' and ``generally unhealthy.'' The use of the 
descriptor ``unhealthy for sensitive groups,'' for PSI values from 101 
to 150, was intended to appropriately caution members of sensitive 
groups 6 without unduly alarming the general public. This 
revision recognized that the NAAQS are established to protect sensitive 
groups, such that at air quality concentrations just above the 
numerical level of NAAQS the general population is unlikely to 
experience exposures of concern. Secondly, while the ``moderate'' 
category (PSI values of 51 to 100) was not divided into two categories, 
allowance was made to create, in essence, a sub-category in the upper 
half of this range (PSI values of 76 to 100) for pollutants for which a 
limited health notice might be appropriate. Such a limited notice would 
recognize that the NAAQS are not risk free, and that even at 
concentrations below the numerical level of a NAAQS some extremely 
sensitive individuals may experience exposures of concern for some 
pollutants. The only other change made to the PSI was to replace the 
descriptor ``very unhealthful'' (PSI values from 201 to 300) with the 
descriptor ``very unhealthy.'' The other categories of ``good'' (PSI 
values from 0 to 50) and ``hazardous'' (PSI values from 301 to 500) 
were left unchanged.
---------------------------------------------------------------------------

    \6\ The staff draft recognized that groups may be ``sensitive'' 
or particularly at-risk to the effects of a pollutant due to 
inherent sensitivity, medical conditions and exposure conditions. 
More specifically, sensitive groups at increased risk to 
O3 effects, include active children and outdoor workers 
who regularly engage in outdoor activities and people with 
preexisting respiratory disease (e.g., asthma, chronic obstructive 
lung disease). Some individuals within these groups are unusually 
responsive to O3 and may experience much greater 
functional and symptomatic effects from exposure to O3 
than the average person in the group.
---------------------------------------------------------------------------

    Consistent with these structural changes and with the new 8-hour 
03 NAAQS, the staff draft identified breakpoints for the 
03 sub-index in terms of 8-hour 03 concentrations 
to the extent possible based on the available health effects 
information. A breakpoint between the good and moderate categories 
needed to be defined since there is no annual standard for 
03 to use as the breakpoint. An 8-hour 03 
concentration of 0.06 ppm was identified based in part on risk 
estimates done in conjunction with the review of the 03 
NAAQS which suggested that risk to healthy people likely becomes 
negligible at this level (Whitfield et al., 1996). This consideration 
was judged by staff to be a more appropriate basis for distinguishing 
between good and moderate categories than the historical approach of 
setting this breakpoint equal to one-half the numerical level of the 
short-term standard in the absence of an annual standard. Further, a 
breakpoint at this level would result in a sufficiently broad range of 
concentrations for the moderate category to facilitate forecasting and 
to make gradations in air quality more visually apparent in the Ozone 
Map. On the other hand, the concentration of 0.07 ppm, 8-hour average, 
was judged by staff as the appropriate breakpoint for starting to 
convey a limited health message for extremely sensitive individuals. 
Thus, this intermediate level of 0.07 ppm, associated with a PSI value 
of 75, resulted in essentially creating a sub-category in the upper 
half of the moderate category. Conveying such a limited health message 
for extremely sensitive individuals at concentrations just below the 
level of the NAAQS is consistent with the advice of CASAC during the 
review of the 03 NAAQS (Wolff, 1995).
    For PSI categories above the numerical level of the 03 
NAAQS, staff again drew in part upon the risk assessment (Whitfield et 
al., 1996) done in conjunction with the review of the NAAQS to provide 
a basis for selecting the breakpoint between the generally unhealthy 
and very unhealthy categories (corresponding to a PSI value of 200). 
Our risk assessment estimates that above a level of 0.12 ppm, 8-hour 
average, healthy individuals (adults and children) at prolonged, 
moderate exertion would likely experience the following risks: (1) 
Approximately 50 percent are estimated to experience temporary moderate 
lung function impairment, (2) approximately 20 percent are estimated to 
experience temporary large lung function impairments, and (3) 
approximately 10 to 15 percent are estimated to experience temporary 
moderate to severe respiratory symptoms (e.g., chest pain and 
aggravated cough). Individuals with asthma or other respiratory 
conditions would be more severely impacted than healthy individuals, 
leading some to increase medication usage and seek medical attention, 
such as increased doctor visits, increased emergency room and clinic 
visits, and increased hospital admissions. Staff judged that it was 
appropriate to characterize risks at these levels and above as being 
very unhealthy. The draft breakpoint between the two new categories 
(corresponding to a PSI value of 150) was set at 0.10 ppm, 8-hour 
average. This is the level at which staff judged that exposures are 
associated with an increase in the number of individuals who could 
potentially experience effects, including possible respiratory effects 
in the general population and a greater likelihood of respiratory 
symptoms and breathing difficulty in sensitive groups. For many 
locations across the country, this 8-hour average breakpoint of 0.10 
ppm approximately corresponds to a 1-hour average concentration of 0.12 
ppm, the level of the 1-hour 03 standard.
    Since no human health effects information was available for 8-hour 
average O3 concentrations at significantly higher levels, 
the breakpoints at the upper end of the PSI scale (between the very 
unhealthy and hazardous categories and the SHL which corresponds to the 
top of the PSI scale of 500) were retained in terms of the existing 1-
hour average concentrations.
3. Related Informational Materials
    In April, 1998, we put on the AIRNOW Web site a draft booklet, 
called ``SMOG--Who Does It Hurt? What You Need To Know About Ozone and 
Your Health,'' that provides information for the general public about 
O3 health effects and is based on

[[Page 67824]]

scientific information gained in the recent review of the O3 
standard. The impetus for the development of this booklet was the 
recognition that many members of the public would appreciate more 
detailed information about the health effects associated with different 
levels of air pollution, especially since better understanding of 
health effects empowers individuals to make personal decisions 
regarding exposure reduction. This recognition was encouraged by 
commenters on the O3 NAAQS proposal who endorsed increasing 
the specificity of warnings with regard to health effects. Such 
commenters noted that citizens are capable of dealing with complex 
information and that individuals with respiratory disease and their 
families appreciate such information. ``SMOG--Who Does It Hurt?'' was 
designed to provide, in simple language, enough detail for individuals 
to understand who is at most risk from O3 exposure and why, 
the nature of O3 health effects, and a detailed explanation 
of how individuals can reduce the likelihood of exposure using common 
everyday activities as examples. This booklet was also intended to 
support programs such as the Ozone Mapping Project and State/local 
community action programs.
    Currently, there are other materials available that provide 
information about O3 and the PSI on the AIRNOW web site. 
Information about ground-level as contrasted to stratospheric 
O3 may be found in EPA's publication ``Ozone: Good Up High, 
Bad Nearby.'' The EPA's video ``Ozone Double Trouble'' also provides 
information about ground-level and stratospheric O3 and the 
health effects associated with exposure to ground-level O3, 
or smog. A short fact sheet, called the ``Air Quality Guide,'' provides 
information about O3 health effects and the sources of 
ground-level O3. The brochure ``The Pollutant Standards 
Index'' (EPA 1994) will be updated to reflect final revisions to the 
PSI and will include as guidance pollutant-specific health effects and 
cautionary statements.
4. What Was the Feedback on the Staff Draft?
    a. Focus Groups. We sponsored eight focus groups to help evaluate 
how effectively the PSI descriptors and the colors used with the Ozone 
Map, the related cautionary statements, and the O3 health 
effects booklet communicate air quality and health effects information. 
The focus groups were conducted by a contractor, including the 
selection of participants, securing meeting facilities, and producing 
necessary materials. The methods and materials used and the results 
from the focus groups are summarized below and presented in a final 
report, ``Report of the Focus Groups on the Ozone Map, the Pollutant 
Standards Sub-Index for Ozone, and the Ozone Health Effects Booklet,'' 
(SAIC, 1998) available in the docket.
    Background. From August to October, 1998, focus groups were held in 
eight locations around the country that have different air quality with 
respect to ozone. Five focus groups, held in Denver, CO; Atlanta, GA; 
Houston, TX; San Bernardino, CA; and St. Louis, MO; were comprised of 
members of the general public. A focus group held in Miami, FL was 
comprised of people over 50 years of age with chronic lung disease 
(asthma, chronic bronchitis, or emphysema). Another focus group, held 
in Chicago, IL was comprised of urban parents of children with asthma. 
Lastly, in October, a focus group was conducted in Los Angeles that was 
comprised of journalists. Twelve participants and three alternates were 
recruited for each of the eight focus groups. Participants in the 
general public focus groups were selected to fit a profile that matched 
the demographic characteristics of each city in terms of ethnicity, 
age, gender, and education level. The participants in the Miami and 
Chicago focus groups were selected to represent target audiences that 
EPA believes may benefit most from understanding and applying the 
information provided by the PSI, the Ozone Map, and the O3 
health effects booklet. Journalists were selected as a target audience 
because they use these informational materials to inform and educate 
the public.
    At the focus groups, participants were asked about various versions 
of the Ozone Map, and the PSI descriptors presented in the legends of 
the maps, related informational materials such as the cautionary 
statements and O3 health effects booklet, and the Index 
name. Four different versions of the Ozone Map were compared for 
effectiveness in conveying information about air quality and associated 
health effects. Each version of the map showed O3 levels in 
the eastern third of the U.S. on a day with high O3 
concentrations. The first three maps differed only in the descriptors 
used in the legend (Maps 1 and 2) and in the addition of the definition 
of sensitive groups to the bottom of the map (Map 3). The fourth map 
used two shades of yellow in the moderate category to depict a 
subcategory that could be associated with a limited health message. The 
comparison of these maps evaluated the most basic configuration of 
information, the colors and descriptors associated with different PSI 
categories, which are used not only with the Ozone Map, but are also 
often used in newspaper reports. With a minimal introduction, the 
participants were asked questions about each map to determine if they 
understood what that map says about air quality and associated health 
effects. In addition, the four maps were displayed side-by-side and 
participants were asked: Which map does the best job of communicating 
whether air quality was good or bad for your health? Which map did you 
prefer?
    Lastly, because comments received earlier from many State and local 
agencies indicated a preference for the name ``Air Quality Index 
(AQI),'' rather than the ``PSI,'' participants in four of the seven 
focus groups (Atlanta, Houston, Miami and Chicago) were asked which of 
two names (Pollutant Standards Index or Air Quality Index) they 
preferred and why.
    Participants also were shown the cautionary statements included 
with the staff draft (and used in conjunction with the Ozone Map) for 
the ``moderate,'' ``unhealthy for sensitive groups,'' and ``generally 
unhealthy'' categories, and were asked questions to evaluate the 
effectiveness of the statements in providing cautionary information. In 
addition, the O3 health effects booklet, ``SMOG--Who Does It 
Hurt?'' was evaluated to assess how well it conveys information in an 
easily understandable form about three basic concepts, O3 
health effects, sensitive groups, and ways to minimize exposures of 
concern. The booklet was designed to communicate these three basic 
concepts that staff believe are important to enhance people's 
understanding of the PSI. Participants read the booklet and then 
answered questions to determine if they understood the three basic 
concepts.
    Results. The results of the focus groups held across the nation 
were fairly consistent. Only the results pertaining to the maps and 
descriptors are discussed below, since these results were considered in 
the development of this proposal. Results pertaining to the cautionary 
statements and the O3 health effects booklet have been 
considered in revising these related informational materials.
    The messages of the maps were generally well understood. Comments 
indicated that the descriptor ``unhealthy for sensitive groups'' 
communicates the intended health effects information. Participants 
identified that at this level only members of sensitive groups, and not 
the general population, should be concerned about personal exposure.

[[Page 67825]]

Many participants in each group preferred the simpler descriptor 
``unhealthy'' to ``generally unhealthy.''
    Considering the first three maps, participants commented that the 
definition of sensitive groups, added in Map 3, provides information 
that they found useful. Whereas most participants expected the 
sensitive groups to include those with respiratory diseases, such as 
asthma, the inclusion of healthy active children and outdoor workers in 
the definition of sensitive group was a surprise to many participants. 
The majority of participants agreed that Map 3 communicated air quality 
and health effects information most effectively, and it was also the 
preferred Map. There were a couple of participants in each group who 
preferred a simpler map.
    The responses from the focus groups about Map 4 reflected confusion 
on the part of many participants about the two shades of yellow used to 
depict the moderate category. This confusion was due in part because 
only one shade of yellow was apparent in the legend. Although many 
participants understood that the lighter shade of yellow represented 
better air quality, many felt this information was of questionable 
value since the legend did not explain what this meant in terms of a 
health message. Some noted that without an associated health message, 
it was not clear why different colors or shadings would be used to 
depict the ``moderate'' category. As part of further discussion on the 
cautionary statement associated with the ``moderate'' category, 
participants learned that there was, in essence, a subcategory at the 
upper end of this range for extremely sensitive individuals. Some 
participants then questioned why the lower end of the moderate range 
should not just be included in the good category if there was no 
associated health message.
    Almost all of the participants preferred the name Air Quality Index 
to Pollutant Standards Index. In general, participants felt that the 
name Air Quality Index communicates what the index is about more 
effectively than the name Pollutant Standards Index. Participants 
noted, for example, that the name Pollutant Standards Index does not 
indicate that the index is about air quality rather than pollution in 
general.
    b. State/local agencies. In the many meetings with State and local 
agencies and national and regional associations, one key issue that 
continued to be discussed in the context of the Ozone Map and community 
action programs was the issue of what colors to associate with the 
``unhealthy for sensitive groups'' and ``generally unhealthy'' 
categories in particular. These discussions typically focused on which 
category should be associated with the color red. As at the January 
workshop, some have maintained that red should be used for the 
``unhealthy for sensitive groups'' category. Others expressed the view 
that red should be used when air quality is in the ``generally 
unhealthy'' category and that orange should be used for the ``unhealthy 
for sensitive groups'' category. These commenters have argued that 
given the form of the standard, using red at the level of the standard 
could allow many days to be classified as ``code red'' days in 
community action programs, even when the standard is attained in that 
area and public health is being protected. One commenter from a State 
agency that used the categories and health advisories from the staff 
draft, together with the color orange when air quality was in the 
``unhealthy for sensitive groups'' category and red when air quality 
was in the ``generally unhealthy'' category, indicated that their 
agency encouraged the same emissions reductions activities when air 
quality was in either category. The commenter reported that people 
appeared to understand the difference in the health advisories and to 
take both levels of air quality advisories seriously.

C. What Is the Basis for the Proposed Revisions?

    The primary consideration that shaped these proposed revisions is 
the importance of providing nationally uniform health information 
associated with daily ambient levels of the air pollutants included in 
the index, consistent with the requirement of section 319 of the Act 
for an index to achieve national uniformity in daily air quality 
reporting. More specifically, the revisions to the O3 and PM 
NAAQS provide the basis for the proposed specific changes to the PSI 
sub-indices for O3 and PM to maintain the relationship 
between an index value of 100 and the level of the NAAQS, and to 
establish the relationships between ambient concentrations of these 
pollutants and index values across the full scale of index values from 
0 to 500. The proposed general changes to the structure of the PSI and 
to related informational materials are based on the expanded 
understanding that emerged during these reviews as to the nature of the 
relationships between exposure to ambient concentrations of these 
pollutants and the health effects likely to be experienced, 
consideration of the implications of changes for the other pollutants, 
and the broad input from State and local agencies and the public 
discussed above. The proposed general changes to the PSI and related 
informational materials will expand the use of the PSI to provide more 
pollutant-specific health information, especially when ambient 
concentrations are close to the level of the primary NAAQS.
1. What Are the Proposed General Changes?
    a. Categories and related descriptors, index values and colors. The 
PSI currently incorporates the pollutants O3, PM, CO, 
SO2, and NO2. Index values range from 0 to 
500,7 and the index is segmented into five categories named 
by descriptor words that were chosen to characterize the relationship 
between daily air quality and public health. To reflect better the 
current understanding of the health effects associated with exposure to 
these air pollutants, we are proposing to revise the PSI index values, 
descriptors, and associated colors as shown below in Table 1.
---------------------------------------------------------------------------

    \7\ For NO2, the index ranges from 200 to 500, since 
there is no short-term NAAQS for this pollutant.

[[Page 67826]]



                        Table 1.--Proposed Category Index Values, Descriptors, and Colors
----------------------------------------------------------------------------------------------------------------
   Index
  Values                   Descriptor                              Color                        Purpose
----------------------------------------------------------------------------------------------------------------
0-50......  Good....................................  Green.........................  Convey positive message
                                                                                       about air quality.
51-100....  Moderate................................  Yellow........................  Convey message that daily
                                                                                       air quality is acceptable
                                                                                       from public health
                                                                                       perspective, but every
                                                                                       day in this range could
                                                                                       result in potential for
                                                                                       chronic health effects;
                                                                                       and for O3, convey a
                                                                                       limited health notice for
                                                                                       extremely sensitive
                                                                                       individuals.
101-150...  Unhealthy for Sensitive Groups..........  Orange........................  Health message for members
                                                                                       of sensitive groups.
151-200...  Unhealthy...............................  Red...........................  Health advisory of more
                                                                                       serious effects for
                                                                                       sensitive groups and
                                                                                       notice of possible
                                                                                       effects for general
                                                                                       population when
                                                                                       appropriate.
201-300...  Very Unhealthy..........................  Purple........................  Health alert of more
                                                                                       serious effects for
                                                                                       sensitive groups and the
                                                                                       general population.
301-500...  Hazardous...............................  Maroon........................  Health warnings of
                                                                                       emergency conditions.
----------------------------------------------------------------------------------------------------------------

    These proposed changes reflect the addition of a new category above 
the level of the standard (above a PSI of 100), created by dividing the 
current ``unhealthful'' category into two categories. The ``unhealthy 
for sensitive groups'' category would start just above the level of the 
standard, and index values would range from 101 to 150. The 
``unhealthy'' category would start at an index value of 151 and range 
to an index value of 200.
    When air quality is in the ``unhealthy for sensitive groups'' 
range, people that are in the sensitive group, whether the sensitivity 
is due to medical conditions, exposure conditions, or inherent 
sensitivity, may experience exposures of concern. However, exposure to 
ambient concentrations in this range are not likely to result in 
exposures of concern for most healthy people. The descriptor 
``unhealthy for sensitive groups'' was chosen to convey this message 
clearly. Participants in focus groups clearly understood that 
``sensitive groups'' does not refer to the general public, indicating 
that this descriptor effectively communicates the intended health 
message. This category would include a caution that while perhaps of 
interest to all citizens, would be of particular interest to 
individuals and families of individuals who are members of sensitive 
groups.
    As air quality moves into the ``unhealthy'' range, exposures are 
associated with an increase in the number of individuals who could 
potentially experience effects and includes a greater proportion of 
members of the general public. Based on input received on the staff 
draft revisions, the descriptor ``unhealthy'' appropriately 
characterizes air quality in this range and does not need to be 
modified further by the word ``generally'' as in the staff draft.
    In addition to an increasing number of exposures of concern, when 
air quality moves into the ``unhealthy'' range and above, individuals 
who were affected at lower levels, typically members of sensitive 
groups, are likely to experience more serious health effects than 
members of the general public. To reflect this understanding, it is 
appropriate to convey two messages in the cautionary statements for 
both the ``unhealthy'' and ``very unhealthy'' categories. One message 
is directed to members of sensitive groups, and the other is directed 
to the general public. The use of a distinct cautionary message for 
members of sensitive groups is entirely consistent with an original 
goal that the index be based on the relationships between pollutant 
concentrations and adverse health effects within various groups, e.g., 
aggravation of disease in people with respiratory disease and incidence 
of respiratory effects in healthy people. Guidance on pollutant-
specific cautionary statements related to the categories of the PSI is 
discussed below in section II.C.3.
    We are not proposing to add a new category or subcategory below the 
numerical level of the standard to caution extremely sensitive 
individuals, as was previously contemplated or included in the staff 
draft. While commenters on the O3 NAAQS proposal broadly 
endorsed expanding the use of the PSI to provide more specific health 
information around the level of the standard, many commenters did not 
support the addition of another category below the level of the 
standard to convey this message. Many commenters expressed the view 
that the addition of two new categories would unduly complicate the 
index. Further, we recognize that while such a category may be 
meaningful and appropriate for O3, based on the expanded 
information from the most recent O3 NAAQS review, it would 
not be an appropriate distinction for the other pollutants included in 
the index. Rather, this proposal addresses these issues by setting the 
breakpoint between good and moderate categories for O3 at 
the concentration where a limited health message for extremely 
sensitive individuals could appropriately be conveyed and by providing 
guidance on pollutant-specific cautionary statements for use in 
conjunction with PSI reporting (discussed in section II.C.3 below and 
in a related guidance document). This approach is intended to retain 
simplicity in the index while allowing for more detailed cautionary 
information to be made available to the public when appropriate.
    Consistent with the overarching goal of national uniformity in the 
reporting of air quality, we are proposing that the specific colors 
listed in Table 1 be associated with each category. While the PSI can 
be reported without the use of colors (through text and numbers alone), 
when the index is reported using colors, we propose to require that 
only these specified colors be used. Three examples of PSI reports that 
use color are the color bars that appear in many newspapers, the color 
scales on State and local agency web sites, and the color contours of 
the Ozone Map. We have participated in many discussions with State and 
local agencies and associations regarding which specific colors should 
be associated with the PSI categories, particularly above the level of 
the standard. These discussions typically have been in the context of 
either the Ozone Mapping Project or community action programs. It is 
clear that the color associated with a category can be part of the 
health effects and cautionary message being conveyed, and that 
different colors convey different messages to different people. Were 
various State and local agencies to use different colors to represent 
the same category, and thus the same level of air quality, it could 
well send a confusing message about air quality and associated health 
effects to the public. Because it is a fundamental goal of the PSI to

[[Page 67827]]

provide nationally uniform information about daily air quality and the 
public health messages that are appropriately associated with various 
daily air quality levels, in a format that is timely and easily 
understood, we believe that requiring specified colors when the PSI 
categories are reported in color format is both necessary and 
appropriate.
    Further, we believe that the specific colors being proposed are 
appropriate for the health messages being conveyed in each category. As 
discussed in the section above, the results of the focus groups 
indicate that, above the level of the standard, the combination of 
colors and descriptors proposed by us effectively communicates the 
intended health effects message. The comments of focus group 
participants (SAIC, 1998) support the generally accepted view that the 
color red sends a strong cautionary message. We believe that this color 
is most appropriate to use when effects are likely to occur in the 
general population, and when more serious effects are likely in members 
of sensitive groups. We believe that the combination of the use of 
orange and red for the two categories above the level of the standard 
appropriately conveys a gradation of concern that is consistent with 
our understanding of the likely public health effects associated with 
these categories. We note that the numerical levels of the 8-hour 
average O3 NAAQS and the 24-hour average PM NAAQS were set 
in conjunction with specific forms of these standards which have the 
effect of allowing multiple days a year during which the level of the 
standard can be exceeded. These combinations of levels and forms 
provide the requisite degree of public health protection, even when 
some days reach air quality levels above the level of the standards. 
Thus, it is consistent with the selection and definition of these NAAQS 
that a gradation of colors be used, and that the color red be specified 
for the PSI category with a stronger cautionary message.
    As an alternative to requiring the use of specified colors, we are 
soliciting comment on the option of recommending, rather than 
requiring, the use of these colors when reporting agencies choose to 
report the PSI in color format. In soliciting comment on this 
alternative, we are seeking to allow communities maximum flexibility in 
PSI reporting, while still preserving a nationally uniform air quality 
index. We therefore request that commenters addressing this issue 
discuss how this more flexible approach would satisfy the statutory 
language requiring a nationally uniform air quality index if different 
colors may be used across the nation to represent the same range of air 
quality.
    b. Reporting requirements. We propose to change 40 CFR part 58.50 
to require reporting of the PSI in all Metropolitan Statistical Areas 
(MSAs) 8 with a population over 350,000, instead of all 
urbanized areas with a population over 200,000. This change is being 
proposed for consistency with the other monitoring regulations in part 
58, which are or will be based on MSAs. This change does not, however, 
have a significant impact on who is required to report, since virtually 
the same number of cities would be covered under the proposed reporting 
requirement as are covered under the existing requirement.
---------------------------------------------------------------------------

    \8\ A complete list of MSAs and their boundaries can be found in 
the Statistical Abstract of the United States (1998).
---------------------------------------------------------------------------

    Consistent with early input from State and local agencies, we are 
proposing to change the rounding conventions used to calculate index 
values corresponding to pollutant concentrations at and above the 
numerical level of the NAAQS to be consistent with the rounding 
conventions used in defining the NAAQS for each pollutant. This will 
avoid situations where a health advisory could be issued that describes 
the air as unhealthy, when in fact the numerical level of the standard 
has not been exceeded. The revised rounding conventions are presented 
below in the proposed appendix G--Uniform Air Quality Index and Daily 
Reporting.
    The proposed rule retains the requirements to identify the area for 
which the PSI is being reported, the time period covered by the report, 
the ``critical'' pollutant for which the reported PSI value was 
derived, the PSI value, and the associated category descriptor. The 
proposed rule adds two requirements, (1) to report the associated 
category color if a color format is used and, (2) to report all PSI 
values greater than 100. Because different sensitive groups are at-risk 
from different pollutants, issuing advisories for all sensitive groups 
who may be affected at PSI values greater than 100 clearly improves 
public health protection. The proposed rule continues to encourage, but 
does not require, that PSI reports include the PSI for sub-divisions of 
the MSA (if there are important differences in air quality across sub-
divisions of the MSA), the actual pollutant concentrations, possible 
causes for high index values, and appropriate health effects and 
cautionary statements (based on the guidance discussed in section 
II.C.3 below). These topics are also discussed in our updated 
``Guideline for Public Reporting of Daily Air Quality--Pollutant 
Standards Index (PSI)'' (EPA 1998b).
    The proposed rule emphasizes the importance of forecasting the PSI 
by specifying that forecasted values should be reported, when possible, 
but does not require that forecasted values be reported. Given the 
importance of the O3 sub-index in a large number of MSAs, 
and the use of an 8-hour averaging time for calculating the 
O3 sub-index value, forecasting the O3 index 
value is now more beneficial than before. For a health advisory system 
to be effective, people need to be notified as early as possible to be 
able to avoid exposures of concern. Because the proposed O3 
sub-index is based on the 8-hour O3 NAAQS, forecasting 
O3 concentrations clearly would have increased value in 
providing cautionary statements to the public. In the past, when a 
health advisory was issued because the PSI value of 100 had been 
exceeded for the 1-hour O3 NAAQS, people potentially had 
time to avoid exposures of concern because O3 levels tend to 
remain elevated for several hours during the day. With an 8-hour 
standard, however, this would not be the case, since by the time the 
level of the 8-hour NAAQS has been exceeded and a health advisory 
issued, the potential for exposures of concern would likely have passed 
for that day. Forecasting 8-hour maximum O3 concentrations 
would facilitate the risk-reduction function of the PSI by giving 
people time to limit or avoid exposures of concern. We recognize that 
many State and local air agencies are already issuing health advisories 
based on forecasted O3 concentrations. Since we have 
determined that forecasting would add much to the benefits of PSI 
reporting, we will be making available guidance on starting a 
forecasting program (EPA 1999) in an area or MSA where forecasting is 
not presently done. Included in the document will be guidance on using 
hourly O3 concentrations as predictors for 8-hour averages.
    c. Index name. Many State and local agencies have encouraged us to 
change the name of the PSI to the Air Quality Index, or AQI, since many 
agencies already use the name AQI when reporting the PSI value to the 
public. Most participants in the focus groups preferred the name AQI, 
commenting that it more clearly identified the index as relating to the 
quality of the air rather than to environmental pollution in general. 
On the other hand, we note that changing the name may result in 
confusion due to historical familiarity and usage, not only in the U.S. 
but

[[Page 67828]]

internationally, since the PSI has been used by many countries 
throughout the world for many years. Based on these considerations, we 
are soliciting comment on changing the name of the Pollutant Standards 
Index (PSI) to the Air Quality Index (AQI).
2. What Are the Proposed Changes to the Sub-Indices?
    To conform to the proposed general changes to the PSI discussed 
above, and to reflect the recent revisions to the O3 and PM 
NAAQS, we are proposing changes to the sub-indices for O3, 
PM, CO, and SO2; no conforming changes are necessary for the 
NO2 sub-index. The proposed sub-indices are summarized below 
in Table 2, in terms of pollutant concentrations that correspond to 
breakpoints in the index, and are discussed in the following sections. 
These sub-indices are presented in more detail in the proposed appendix 
G to reflect the proposed changes to the numerical rounding conventions 
for calculating index values.

                       Table 2.--Breakpoints for O3, PM2.5, PM10, CO, and SO2 Sub-indices
----------------------------------------------------------------------------------------------------------------
                                O3                              PM
                -----------------------------------------------------------------
   PSI value                                       PM2.5, 24-hr     PM10, 24-hr   CO, 8-hr (ppm)    SO2, 24-hr
                    8-hr (ppm)      1-hr (ppm)     (g/    (g/                        (ppm)
                                                        m3)             m3)
----------------------------------------------------------------------------------------------------------------
 50............   0.07            ..............            15              50               4            0.03
100............   0.08                    0.12              65             150               9            0.14
150............   0.10                    0.16            100*             250              12            0.22
200............   0.12                    0.20            150*             350              15            0.30
300............   0.40 (1-hr)             0.40            250*             420              30            0.60
400............   0.50 (1-hr)             0.50            350*             500              40            0.80
500............   0.60 (1-hr)             0.60            500*             600              50            1.00
----------------------------------------------------------------------------------------------------------------
*If a different SHL for PM2.5 is promulgated, these numbers will change accordingly.

    a. Ozone sub-index. On July 18, 1997, we revised the O3 
primary NAAQS to replace the 1-hour standard with a new standard with 
an 8-hour average at a level of 0.08 ppm and a form based on the 3-year 
average of the annual fourth-highest daily maximum 8-hour average 
O3 concentrations measured at each monitor within an area 
(62 FR 38856-38896). These revisions were based on findings from the 
most recent review of the NAAQS indicating that the new primary 
standard will provide increased protection to the public, especially 
children active outdoors and other sensitive groups, against a wide 
range of O3-induced health effects, including decreased lung 
function; increased respiratory symptoms; hospital admissions and 
emergency room visits for respiratory causes, among children and adults 
with pre-existing respiratory disease such as asthma; inflammation of 
the lung; and possible long-term damage to the lungs. In setting this 
standard, we recognized that there is no discernible threshold below 
which health effects do not occur, that the standard is not risk free, 
and, thus, that exposures of concern are possible below the numerical 
level of the standard for some extremely sensitive individuals.
    Based on feedback on the staff draft, above a PSI value of 100, we 
propose to adopt the revisions to the O3 sub-index that were 
presented in the staff draft, and to make changes to the staff draft 
below that value. The proposed revisions to the O3 sub-index 
above the level of the standard, and the rationale for these proposed 
revisions, are discussed above in section II.B.2. Below the level of 
the standard, at a PSI value of 50, we propose that 0.07 ppm, 8-hour 
average, be the breakpoint between the good and moderate categories. As 
in the staff draft, this concentration is judged by staff as an 
appropriate breakpoint for starting to convey a limited health message 
for extremely sensitive individuals. This breakpoint was adopted 
because comments received indicated that the draft subcategories within 
the moderate category created confusion, and that having a distinct 
subcategory within moderate with no health message was unnecessary. We 
recognize that this breakpoint defines a category with a somewhat 
narrower range of concentrations. However, we believe this breakpoint 
makes an important distinction to emphasize the limited health message 
for extremely sensitive individuals. The effect of this range on 
forecasting is addressed in the forecasting guidance. Beyond this 
issue, comments received on the staff draft O3 sub-index, 
discussed in section II.B.4, have been generally positive and have 
focused on the presentation of the sub-index through the Ozone Mapping 
Project and on the wording of associated cautionary statements included 
as guidance. These proposed revisions are consistent with the proposed 
general changes to the PSI discussed above in section II.C.1.a.
    These proposed revisions reflect the new 8-hour O3 NAAQS 
and will in almost all areas result in a more health protective index 
than the current index based on the 1-hour O3 standard. 
However, we recognize that a very small number of areas in the U.S. 
have atypical air quality patterns, with very high 1-hour daily peak 
O3 concentrations relative to the associated 8-hour average 
concentrations. In such areas, the use of the current 1-hour sub-index 
may be more health protective on a given day than the proposed 8-hour 
sub-index. To allow for the reporting of the more health protective 
sub-index value, we also propose to retain the 1-hour sub-index at and 
above PSI values of 100 and to allow the reporting of the higher of the 
two O3 sub-index values. Thus, both the new 8-hour and the 
current 1-hour sub-indices, as shown in Table 2, are included in the 
proposed appendix G. To conform to the proposed general changes to the 
PSI, a breakpoint of 0.16 ppm, 1-hour average, has been added to the 1-
hour sub-index at a PSI value of 150. This value is the mid-point of 
the breakpoints at PSI values of 100 and 200. Since for the large 
majority of areas the 8-hour sub-index will be more health protective, 
we are not proposing to require all areas to calculate both sub-index 
values. Rather, we are proposing to allow areas the flexibility to 
calculate both sub-index values and, when both sub-index values are 
calculated, to require that the higher value be reported. We are 
specifically soliciting comment on this proposed approach.
    b. PM sub-index. On July 18, 1997, we revised the PM NAAQS by 
adding a new set of standards for fine particles, or PM2.5, 
set at levels of 15 g/m3 (annual) and 65 
g/m3 (24-hour average) (62 FR 38652-38760). These 
revisions were based on findings from the most recent review of the PM 
NAAQS that recently published studies have

[[Page 67829]]

indicated that serious health effects were more closely associated with 
the levels of the smaller particle subset of PM10. These 
health effects include premature mortality and increased hospital 
admissions and emergency room visits, primarily in the elderly and 
individuals with cardiopulmonary disease; increased respiratory 
symptoms and disease in children and individuals with cardiopulmonary 
disease such as asthma; decreased lung function, particularly in 
children and individuals with asthma; and alterations in respiratory 
tract defense mechanisms. In addition, PM10 standards were 
retained at the same levels of 50 g/m\3\ (annual) and 150 
g/m\3\ (24-hour average) to continue to provide protection 
against health effects associated with the coarse particle subset of 
PM10, including aggravation of asthma and respiratory 
infections. To reflect these revisions to the PM NAAQS, we are 
proposing to add a new sub-index for PM2.5, and to make 
conforming changes to the sub-index for PM10, consistent 
with the proposed general changes to the PSI described above in section 
II.C.1.a. These proposed sub-indices are summarized above in Table 2 
and discussed below.
    New PM2.5 sub-index. Consistent with the basic structure 
of the PSI, an index value of 100 corresponds to the level of the 24-
hour PM2.5 NAAQS, 65 g/m\3\, and an index value of 
50 corresponds to the level of the annual NAAQS, 15      g/
m\3\. Also consistent with the basic structure of the PSI, the upper 
bound index value of 500 corresponds to the SHL, established in section 
51.16 of the CFR under the Prevention of Air Pollution Emergency 
Episodes program. The SHL is set at a level that represents an imminent 
and substantial endangerment to public health. In mid-1999, we will 
propose revisions to the Prevention of Air Pollution Emergency Episodes 
program, which will include an SHL for PM2.5. In advance of 
proposing an SHL for PM2.5, we are now proposing to 
establish a PM2.5 concentration 9 to be 
associated with a PM2.5 index value of 500.
---------------------------------------------------------------------------

    \9\ Should the final SHL for PM2.5, when promulgated, 
be different from this concentration, we will revise this 
PM2.5 sub-index accordingly.
---------------------------------------------------------------------------

    In proposing to establish this PM2.5 concentration to be 
associated with a PM2.5 index value of 500, the primary 
focus is on evidence linking mortality with increases in PM 
concentration. The current SHL for PM10 (600 g/
m\3\) was established on the basis of the increased mortality found 
during historical wintertime pollution episodes in London, where PM 
concentrations, measured as British Smoke, were in the range of 500 to 
1000 g/m\3\ (52 FR 24687-24688). We believe that these studies 
still provide the best scientific support for significant harm levels 
for PM. British Smoke provides an approximate measurement of fine 
particles, since it is considered to measure PM with a cut-point of 
approximately 4.5 microns. While some coarse mode particles are 
included, it has been found that mainly fine mode particles are 
collected using the British Smoke method. In establishing the SHL for 
PM10, we used an assumption that a concentration of 
PM10 can be estimated by adding 100 to a concentration 
measured in terms of British Smoke (52 FR 24688). For the purposes of 
proposing to establish a PM2.5 concentration to be 
associated with a PM2.5 index value of 500, we are assuming 
that particle mass concentration measured by the British Smoke method 
is approximately equivalent to a PM2.5 mass concentration.
    For intermediate breakpoints in the PSI between values of 100 and 
500, PM2.5 concentrations are proposed that generally 
reflect a linear relationship between increasing index values and 
increasing PM2.5 values. The available scientific evidence 
of health effects related to population exposures to PM2.5 
concentrations between the 24-hour NAAQS level and the proposed SHL 
suggest a continuum of effects in this range, with increasing 
PM2.5 concentrations being associated with increasingly 
larger numbers of people likely experiencing serious health effects (62 
FR 38675; Staff Paper, p. VII-27) The proposed generally linear 
relationship between PSI values and PM2.5 concentrations in 
this range, rounded to increments of 50 g/m3 to 
reflect the approximate nature of such a relationship, is consistent 
with this evidence.
    Conforming changes to the PM10 sub-index. Consistent 
with the retention of the levels of the PM10 NAAQS, we are 
proposing to retain the PM10 sub-index generally and to add 
a new breakpoint at an index value of 150 to conform to the proposed 
additional PSI category. We propose that this breakpoint be set at a 
PM10 24-hour average concentration of 250 g/
m3, the mid-point between the breakpoints associated with 
index values of 100 and 200. We believe that the PM10 sub-
index, with this conforming change, remains appropriate for the public 
health protection purposes of the PSI.
    c. Conforming changes to the CO and SO2 sub-indices. 
Since the current PSI sub-indices reflect the current NAAQS for CO and 
SO2, the only change being proposed today for these sub-
indices is to add a breakpoint to each sub-index at an index value of 
150 to conform to the proposed additional PSI category. We propose that 
these breakpoints be set at concentrations at the mid-points between 
the breakpoints associated with index values of 100 and 200, consistent 
with the approach described above for conforming changes to both the 1-
hour O3 sub-index and the PM10 sub-index. These 
proposed breakpoints are summarized in Table 2 and presented in more 
detail in appendix G to reflect the proposed changes to the numerical 
rounding conventions used to calculate index values. These sub-indices 
will be reviewed in conjunction with the future reviews of the CO and 
SO2 NAAQS.
3. What are the Changes to Related Informational Materials?
    We have edited related informational materials on O3 
prepared in conjunction with the staff draft O3 sub-index, 
such as the cautionary statements, to reflect the input from the focus 
groups and from national, State and local agencies and associations. 
The edits include some of the wording changes suggested to the 
cautionary statements, as well as clarification of the health/air 
quality message associated with the moderate category. In the 
``unhealthy'' and ``very unhealthy'' categories, there are distinct 
cautionary statements for members of sensitive groups and the general 
public. In addition, because different conditions make individuals and 
groups susceptible to the effects of different air pollutants, we have 
developed pollutant-specific health effects and cautionary statements 
for the other pollutants in the index, including PM2.5, 
PM10, CO, SO2, and NO2. The health 
effects and cautionary statements may be found on AIRLINKS (http://
www.epa.gov/airlinks). Our draft guidance on PSI reporting, ``Guideline 
for Public Reporting of Daily Air Quality--Pollutant Standards Index 
(PSI)'' (EPA 1998b), which includes the health effects and cautionary 
statements, is available in the docket and on AIRLINKS.
    The brochure ``The Pollutant Standards Index'' (EPA 1994), contains 
information about the general health effects associated with each 
category, and precautions that sensitive groups and the general public 
should take to avoid exposures of concern. Currently, it contains one 
set of health effects and cautionary statements that are generally 
applicable to all of the pollutants currently included in the PSI, and 
does not identify specific sensitive groups for each of the pollutants. 
In changes to this

[[Page 67830]]

brochure, we will revise the categories and descriptors to be 
consistent with final revisions to the PSI, identify sensitive groups 
in the health effects statements for each of the pollutants, and will 
include the pollutant-specific health effects and cautionary statements 
discussed above.
    The booklet, ``SMOG--Who Does It Hurt?,'' was developed using 
health effects information from the review of the standard and 
therefore already incorporates the concepts of sensitive groups and a 
continuum of effects to background levels of O3. Revisions 
to this booklet will be based on final revisions to the PSI, 
information from the focus groups, and comments from national, State 
and local agencies and associations. Based on these comments, the 
distinction between stratospheric and ground-level O3 will 
be made clearer, and the section ``What does exertion have to do with 
O3-related health effects?'' will include clarification of 
the effect of individual conditioning on exertion levels. In addition, 
we are planning to develop a shorter, summary brochure about 
O3 health effects to complement the ``SMOG--Who Does It 
Hurt?'' booklet, to translate both ``SMOG--Who Does It Hurt?'' and the 
shorter summary booklet into Spanish, and to develop informational 
materials about O3 health effects for primary care 
providers. All of these documents will be made available when revisions 
to the PSI are final, including on the AIRNOW web site.

III. Regulatory and Environmental Impact Analyses

A. Executive Order 12866: OMB Review of ``Significant Actions''

    Under Executive Order 12866, the Agency must determine whether a 
regulatory action is ``significant'' and, therefore, subject to Office 
of Management and Budget (OMB) review and the requirements of the 
Executive Order. The order defines ``significant regulatory action'' as 
one that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of 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 or 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. The OMB has advised us this proposal should be 
construed as a ``significant regulatory action'' within the meaning of 
Executive Order 12866. Accordingly, this action was submitted to the 
OMB for review. Any changes made in response to OMB suggestions or 
recommendations will be documented in the public record and made 
available for public inspection at EPA's Air and Radiation Docket 
Information Center (Docket No. A-98-20).

B. Regulatory Flexibility Analysis/Small Business Regulatory 
Enforcement Fairness Act

    Under the Regulatory Flexibility Act (RFA), 5 U.S.C. 601 et seq., 
EPA must prepare a regulatory flexibility analysis assessing the impact 
of any proposed or final rule on small entities. Under 6 U.S.C. 605(b), 
this requirement may be waived if EPA certifies that the rule will not 
have a significant economic impact on a substantial number of small 
entities. Small entities include small businesses, small not-for-profit 
enterprises, and governmental entities with jurisdiction over 
populations less than 50,000 people.
    Today's proposal to revise the PSI program modifies existing air 
quality reporting requirements for MSA's with populations over 350,000 
people. Today's proposal, if promulgated, will not establish any new 
regulatory requirements affecting small entities. On the basis of the 
above considerations, EPA certifies that today's proposal will not have 
a significant economic impact on a substantial number of small entities 
within the meaning of the RFA. Based on the same considerations, EPA 
also certifies that the new small-entity provisions in Section 244 of 
the Small Business Regulatory Enforcement Fairness Act (SBREFA) do not 
apply.

C. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 
104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, local and tribal governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
1 year.
    EPA has determined that today's proposal, if promulgated, would not 
include a Federal mandate that may result in estimated costs of $100 
million in any 1 year to either State, local, or tribal governments, in 
the aggregate, or to the private sector. Accordingly, EPA has 
determined that the provisions of section 202 of the UMRA do not apply 
to this rulemaking.

D. Paperwork Reduction Act

    Today's proposal does not establish any new information collection 
requirements beyond those which are currently required under the 
Ambient Air Quality Surveillance Regulations in 40 CFR part 58 (OMB 
#2060-0084, EPA ICR No. 0940.15). Therefore, the requirements of the 
Paperwork Reduction Act do not apply to today's action.

E. Executive Order 13045: Children's Health

    Executive Order 13045, entitled ``Protection of Children from 
Environmental Health Risks and Safety Risks'' (62 FR19885, April 23, 
1997), requires Federal agencies to ensure that their policies, 
programs, activities, and standards identify and assess environmental 
health and safety risks that may disproportionately affect children. In 
today's proposal, EPA identified children as one of the sensitive 
groups which may be at increased risk of experiencing the effects of 
concern following exposure to ozone. The proposed PSI categories, 
descriptors, and cautionary statements all take into consideration the 
increased health risk to children which may result from such exposures. 
Therefore, today's action does comply with the requirements of E.O. 
13045.

F. Executive Order 12848: Environmental Justice

    Executive Order 12848 requires that each Federal agency make 
achieving environmental justice part of its mission by identifying and 
addressing, as appropriate, disproportionately high and adverse human 
health or environmental effects of its programs, policies, and 
activities on minorities and low-income populations in the United 
States.
    The nature of today's action is to inform the general public, 
including minorities and low-income populations, about the nature of 
the air pollution in the areas they live. Today's action establishes a 
uniform tool for States to use to develop programs which will caution 
particularly sensitive people to minimize their exposures and educate 
the public about general health effects

[[Page 67831]]

associated with exposure to different pollution levels. States may also 
use information established as part of the PSI to trigger programs 
designed to reduce emissions to avoid exceedances of the NAAQS. 
Therefore, today's action will help facilitate public participation, 
outreach, and communication in areas where environmental justice issues 
are present.

G. Executive Order 12875: Enhancing Intergovernmental Partnerships

    Under Executive Order 12875, EPA may not issue a regulation that is 
not required by statute and that creates a mandate upon a State, local 
or tribal government, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by those 
governments, or we will consult with those governments. If EPA complies 
by consulting, Executive Order 12875 requires us to provide to OMB a 
description of the extent of our prior consultation with 
representatives of affected State, local and tribal governments, the 
nature of their concerns, copies of any written communications from the 
governments, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 12875 requires us to develop 
an effective process permitting elected officials and other 
representatives of State, local and tribal governments ``to provide 
meaningful and timely input in the development of regulatory proposals 
containing significant unfunded mandates.''
    Today's rule implements requirements specifically set forth by the 
Congress in section 319 of the Act without the exercise of any 
discretion by us. Accordingly, the requirements of section 1(a) of 
Executive Order 12875 do not apply to this rule.

H. Executive Order 13084: Consultation and Coordination with Indian 
Tribal Governments

    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments, or EPA will consult with 
those governments. If EPA complies by consulting, Executive Order 13084 
requires us to provide to OMB, in a separately identified section of 
the preamble to the rule, a description of the extent of our prior 
consultation with representatives of affected tribal governments, a 
summary of the nature of their concerns, and a statement supporting the 
need to issue the regulation. In addition, Executive Order 13084 
requires us to develop an effective process permitting elected 
officials and other representatives of Indian tribal governments ``to 
provide meaningful and timely input in the development of regulatory 
policies on matters that significantly or uniquely affect their 
communities.''
    Today's rule implements requirements specifically set forth by the 
Congress in section 319 of the Act without the exercise of any 
discretion by us. Accordingly, the requirements of section 3(b) of 
Executive Order 13084 do not apply to this rule.

I. National Technology Transfer and Advancement Act

    As noted in the proposed rule, Section 12(d) of the National 
Technology Transfer and Advancement Act of 1995 (NTTAA), Pub L. No. 
104-113, Sec. 12(d) (15 U.S.C. 272 note) directs EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. Voluntary 
consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, and business 
practices) that are developed or adopted by voluntary consensus 
standards bodies. The NTTAA directs EPA to provide Congress, through 
OMB, explanations when the Agency decides not to use available and 
applicable voluntary consensus standards. This action does not involve 
technical standards. Therefore, EPA did not consider the use of any 
voluntary consensus standards.

IV. References

    EPA, (1994) ``Measuring Air Quality: The Pollutant Standards 
Index,'' U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards (MD-10), Research Triangle Park, NC, 27711, EPA 
451/K-94-001.
    EPA, (1997) Review of the National Ambient Air Quality Standards 
for Particulate Matter: Policy Assessment of Scientific and Technical 
Information, OAQPS Staff Paper, Office of Air Quality Planning and 
Standards, Research Triangle Park, NC 27711, EPA-452/R-96-013.
    EPA, (1998a) Community Action Programs: Blueprint for Program 
Design, U.S. Environmental Protection Agency, Office of Mobile Sources, 
Ann Arbor, MI, EPA 420-R-98-003.
    EPA, (1998b) Guideline for Public Reporting of Daily Air Quality--
Pollutant Standards Index (PSI), U.S. Environmental Protection Agency, 
Office of Air Quality Planning and Standards, Research Triangle Park, 
NC, 27711, draft document.
    EPA, (1999) Guideline for Starting an Air Pollution Forecasting 
Program, U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards, Research Triangle Park, NC, 27711, in 
preparation.
    Science Applications International Corporation, (1998) Report of 
Eight Focus Groups on the Ozone Map, the Pollutant Standards Sub-Index 
for Ozone, and the Ozone Health Effects Booklet, Science Applications 
International Corporation, McLean, VA.
    U.S. Department of Commerce, Statistical Abstract of the United 
States, 1998, U.S. Bureau of the Census.
    Whitfield, R.G.; Biller, W.F.; Jusko, M.J.; Keisler, J.M. (1996) A 
probabilistic assessment of health risks associated with short-term 
exposure to tropospheric ozone . Report prepared for U.S. EPA, OAQPS. 
Argonne National Laboratory; Argonne, IL.
    Wolff, G.T., (1995) Letter from Chairman of Clean Air Scientific 
Advisory Committee to the EPA Administrator, dated November 30, 1995. 
EPA-SAB-CASAC-LTR-96-002.

List of Subjects in 40 CFR Part 58

    Environmental protection, Air pollution control, Air quality 
surveillance and data reporting, Ambient air quality monitoring network 
design and siting, Intergovernmental relations, pollutant standards 
index, Quality assurance program.

    Dated: December 1, 1998.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, chapter I of title 40 of 
the Code of Federal regulations is proposed to be amended as follows:

PART 58--AMBIENT AIR QUALITY SURVEILLANCE

    1. The authority citation of part 58 continues to read as follows:

    Authority: 42 U.S.C. 7410, 7601(a), and 7619.

    2. Section 58.50 is revised to read as follows:


Sec. 58.50  Index reporting.

    (a) The State shall report to the general public through prominent 
notice an air quality index in accordance with the requirements of 
appendix G to this part.
    (b) Reporting is required by all Metropolitan Statistical Areas 
with a population exceeding 350,000.

[[Page 67832]]

    (c) The population of a Metropolitan Statistical Area for purposes 
of index reporting is the most recent decennial U.S. census population.
    3. Appendix G is revised to read as follows:

Appendix G--Uniform Air Quality Index and Daily Reporting

General Requirements
    1. What is the PSI?
    2. Why report the PSI?
    3. Must I report the PSI?
    4. What goes into my PSI report?
    5. What colors do I use when I report the PSI?
    6. Is my PSI report for my MSA only?
    7. How do I get my PSI report to the public?
    8. How often must I report the PSI?
    9. May I make exceptions to these reporting requirements?

Calculation

    10. How does the PSI relate to air pollution levels?
    11. Where do I get the pollutant concentrations to calculate the 
PSI?
    12. Do I have to forecast the PSI?
    13. How do I calculate the PSI?
    14. How do I use Table 2 and Equation 1 to calculate the PSI?

Background and Reference Materials

    15. What additional information should I know?
    16. References

General Requirements

1. What Is the PSI?

    The Air Quality Index (PSI) is a tool that simplifies reporting 
air pollution to the general public. The PSI incorporates into a 
single index concentrations of 5 criteria pollutants: ozone 
(O3), particulate matter (PM), carbon monoxide (CO), 
sulfur dioxide (SO2), and nitrogen dioxide 
(NO2). The scale of the index is divided up into general 
categories that are associated with health messages.

2. Why Report the PSI?

    The PSI offers various advantages:
    a. It is simple to create and understand.
    b. It conveys the health implications of air quality.
    c. It promotes uniform use throughout the country.

3. Must I Report the PSI?

    You must report the PSI daily if yours is a metropolitan 
statistical area (MSA) with a population over 350,000.

4. What Goes Into My PSI Report?

    Your PSI report must contain the following:
    a. The reporting area(s) (the MSA or subdivision of the MSA).
    b. The reporting period (the day for which the PSI is reported).
    c. The critical pollutant (the pollutant with the highest index 
value).
    d. The PSI (the highest index value).
    e. The category descriptor and index value associated with the 
PSI and, if reported in a color format, the associated color. Use 
only the following descriptors and colors for the six PSI 
categories:

------------------------------------------------------------------------
             PSI                    Descriptor               Color
------------------------------------------------------------------------
0 to 50.....................  ``Good''..............  Green.
51 to 100...................  ``Moderate''..........  Yellow.
101 to 150..................  ``Unhealthy for         Orange.
                               Sensitive Groups''.
151 to 200..................  ``Unhealthy''.........  Red.
201 to 300..................  ``Very Unhealthy''....  Purple.
301 and above...............  ``Hazardous''.........  Maroon.
------------------------------------------------------------------------

    When appropriate, your PSI report may also contain the 
following:
    a. The name and index value for other pollutants, particularly 
those with an index value greater than 100.
    b. The index values for sub-areas of the reporting area.
    c. Actual pollutant concentrations.
    d. Causes for unusual PSI values.

5. What Colors Do I Use When I Report the PSI?

    If reporting in color format, you must use the colors listed 
above. More specifically the colors you must use are defined in the 
following table for both red, green, blue (RGB) and cyan, magenta, 
yellow, and black (CMYK) color formulas.\1\

                                                 Table 1.--Color Formulations for Reporting the PSI.\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                            Color                                   R            G            B            C            M            Y            K
--------------------------------------------------------------------------------------------------------------------------------------------------------
Green........................................................        0          228            0          224            0          224           30
Yellow.......................................................      255          255            0            0            0          255            0
Orange.......................................................      255          126            0            0          132          255            0
Red..........................................................      255            0            0          255          255            0            0
Purple.......................................................      153            0           76            0          153           80          102
Maroon.......................................................       76            0           38            0           76           38          179
--------------------------------------------------------------------------------------------------------------------------------------------------------
\2\ The color models are based on a 0-255 scale (e.g., 50 percent is 126).

6. Is My PSI Report for My MSA Only?

    Generally, your PSI report applies to your MSA only. However, 
your report does not apply to just your MSA in two situations:
    a. If a significant air quality problem exists (PSI greater than 
100) in areas next to your MSA but not in it (for example 
O3 concentrations are often highest downwind and outside 
an urban area), your PSI report should apply to these areas also.
    b. If different PSI categories apply to different definable 
parts of your MSA, you should report a separate PSI for each part of 
your urban area.
---------------------------------------------------------------------------

    \1\ The RGB model is traditionally used for TV or computer 
monitor colors while CMYK is traditionally used for color printers.
---------------------------------------------------------------------------

7. How Do I Get My PSI Report to the Public?

    You must furnish the daily report to the appropriate news media 
(radio, television, and newspapers). You may make the daily report 
publicly available at one or more places of public access, or you 
may disseminate it by a recorded phone message or a public Internet 
site.

8. How Often Must I Report the PSI?

    You must report the PSI at least 5 days per week. Exceptions to 
this requirement are in Section 9 below.

9. May I Make Exceptions to These Reporting Requirements?

    If the index for a particular pollutant remains below 50 for a 
season or year, then you may exclude the pollutant from your 
calculation of the PSI in Section 13.
    If the PSI remains below 50 for a year, then you may report the 
PSI at your discretion.

Calculation

10. How Does the PSI Relate to Air Pollution Levels?

    For each pollutant, the PSI transforms ambient concentrations to 
a scale from 0 to 500. The PSI is related to the National Ambient 
Air Quality Standard (NAAQS) for each pollutant. The index value of 
100 is always associated with the numerical level of the standard 
for each pollutant. The index value of 50 is associated with annual 
standards (if they exist) for each pollutant. Higher categories of 
the index are based on increasingly serious health effects and 
increasing proportions of the population that are affected. The EPA 
relates the index to other air pollution concentrations through 
linear interpolation based on these levels. The PSI is equal to the 
highest of the numbers corresponding to each pollutant. The 
pollutant responsible for the highest number (the reported PSI) is 
called the ``critical'' pollutant.

11. Where Do I Get the Pollutant Concentrations To Calculate the 
PSI?

    You must use concentration data for four of the five PSI 
criteria pollutants from the State/Local Air Monitoring Station 
(SLAMS) or parts of the SLAMS required under 40 CFR

[[Page 67833]]

58.20. For PM, you need only calculate and report the PSI on days 
for which you have measured air quality data (e.g., particulate 
monitors often report values only every sixth day). You may use 
particulate measurements from monitors that are not reference or 
equivalent methods if you can relate these measurements by linear 
regression to reference or equivalent method measurements.

12. Do I Have to Forecast the PSI?

    You should forecast the PSI at least 24-hours in advance using 
the most accurate and reasonable procedures considering meteorology, 
topography, availability of data, and forecasting expertise. Since 
ozone is a dominant pollutant in air pollution and the form of the 
ozone standard is an 8-hour average, the timing of how the public is 
informed is an important issue. In order for affected people to take 
advantage of this information, it is necessary to consider at least 
a short term forecast or prediction of 8-hour ozone levels for the 
purposes of reporting the PSI. Guidance to this appendix suggest 
ways to do this which require less resources than 24-hour advance 
forecasts (EPA 1999).

13. How Do I Calculate the PSI?

    The PSI is the highest value calculated for each pollutant as 
follows:
    a. Truncate the pollutant concentration from the monitor 
recording the highest concentration in the reporting area to one 
more than the significant digits used in the NAAQS for that 
pollutant. This is equivalent to the rounding conventions used in 
the NAAQS.
    b. Using Table 2, find the two breakpoints that contain the 
concentration.
    c. Using Equation 1, calculate the index.
     d. Round the index to the nearest integer.

                                                            Table 2.--Breakpoints for the PSI
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          These breakpoints--
-------------------------------------------------------------------------------------------------------
                                    PM10      PM2.5  (3 (ppm)  8-hour  O3 (ppm)  1-  (g/      m>g/m3)       CO (ppm)      SO2 (ppm)     NO2 (ppm)       PSIs
                     hour 1          m3)
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.000-0.069.....       -          0-54        0.0-15.4        0.0-4.4       0.000-0.034       (2)         0-50        Good.
0.070-0.084.....       -        55-154        15.5-65.4       4.5-9.4       0.035-0.144       (2)       51-100        Moderate.
0.085-0.104.....  0.125-0.164   155-254       65.5-100.4 5    9.5-12.4      0.145-0.224       (2)       101-150       Unhealthy for sensitive groups.
0.105-0.124.....  0.165-0.204   255-354       100.5 5-150.4
                                                    5         12.5-15.4     0.225-0.304       (2)       151-200       Unhealthy.
0.125-0.374.....  0.205-0.404   355-424       150.5 5-250.4
                                                    5         15.5-30.4     0.305-0.604   0.65-1.24     201-300       Very unhealthy.
(0.155-0.404) 4.
(3).............  0.405-0.504   425-504       250.5 5-350.4
                                                    5         30.5-40.4     0.605-0.804   1.25-1.64     301-400
(3).............  0.505-0.604   505-604       350.5 5-500.4
                                                    5         40.5-50.4     0.805-1.004   1.65-2.04     401-500       Hazardous.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Areas are required to report the PSI based on 8-hour ozone values. However, there are areas where a PSI based 1-hour ozone values would be more
  protective. In these cases, the index for both the 8-hour and the 1-hour ozone values may be calculated and the maximum PSI reported.
\2\ NO2 has no short-term NAAQS and can generate a PSI only above a PSI value of 200.
\3\ 8-hour O3 values do not define higher PSI values (301). PSI values of 301 or higher are calculated with 1-hour O3 concentrations.
\4\ The numbers in parentheses are associated 1-hour values to be used in this overlapping category only.
\5\ If a different SHL for PM2.5 is promulgated, these numbers will change accordingly.

    If the concentration is equal to a breakpoint, then the index is 
equal to the corresponding index in Table 2. However, Equation 1 can 
still be used. The results will be equal. If the concentration is 
between two breakpoints, then calculate the index of that pollutant 
with Equation 1. You must also note that in some areas, the PSI 
based on 1-hour O3 will be more protective than using 8-
hour values (see footnote 1 to Table 2). In these cases you may use 
1-hour values as well as 8-hour values to calculate the index and 
then use the maximum PSI value as the index for O3.

[GRAPHIC] [TIFF OMITTED] TP09DE98.040

Equation 1
Where Ip = the index for pollutant p
    Cp = the truncated concentration of pollutant 
p
    BPHi = the breakpoint that is greater than or equal 
to Cp
    BPLo = the breakpoint that is less than or equal to 
Cp
    IHi = the PSI value corresponding to BPHi
    Ilo = the PSI value corresponding to BPLo.
    If the concentration is larger than the highest breakpoint in 
Table 2 then you may use the last two breakpoints in Table 2 when 
you apply Equation 1. If your O3 values (1-hour and 8-
hour) are in the overlapping category (very unhealthy, see footnote 
4 to Table 2) then you must use Equation 1 for both values and use 
the larger index value for O3.

14. How Do I Use Table 2 and Equation 1 To Calculate the PSI?

    If you observe a 1-hour O3 value of 0.156 ppm, an 8-
hour O3 value of 0.130 ppm, and a PM10 value 
of 210 g/m\3\, then do this:
    a. Find the breakpoints for PM10 at 210
g/m\3\ as 205 g/m\3\ and 354 g/m\3\ 
corresponding to index values 151 and 200;
    b. Find the breakpoints for 1-hour O3 at 0.156 ppm as 
0.155 ppm and 0.404 ppm corresponding to index values 201 and 300;
    c. Find the breakpoints for 8-hour O3 at 0.130 ppm as 
0.125 ppm and 0.374 ppm corresponding to index values 201 and 300;
    d. Apply Equation 1 for 210 g/m\3\, PM10:
    [GRAPHIC] [TIFF OMITTED] TP09DE98.041
    
    e. Apply Equation 1 for 0.156 ppm, 1-hour O3:
    [GRAPHIC] [TIFF OMITTED] TP09DE98.042
    
    f. Apply Equation 1 for 0.130 ppm, 8-hour O3:
    [GRAPHIC] [TIFF OMITTED] TP09DE98.043
    
    g. Find the maximum, 203. This is the PSI.

Background and Reference Materials

15. What Additional Information Should I Know?

    The EPA has developed a computer program to calculate the PSI 
for you. The program works with Windows 95, it prompts for inputs, 
and it displays all the pertinent information for the PSI (the 
index, color, category, health effects, and cautionary language). 
You can download the program at www.epa.gov/airnow. The EPA also 
publishes a brochure on the PSI that explains the index in detail 
(EPA 1999b), guidance that provides associated health effects and 
cautionary statements (EPA 1998), and guidance that explains the 
steps necessary to start an air pollution forecasting program (EPA 
1999a).

16. References

    EPA, (1998) Guideline for Public Reporting of Daily Air Quality-
Pollutant Standards Index (PSI), U.S. Environmental Protection 
Agency, Office of Air Quality Planning and Standards, Research 
Triangle Park, NC, 27711, draft document.
    EPA, (1999a) Guideline for Starting an Air Pollution Forecasting 
Program, U.S. Environmental Protection Agency, Office of

[[Page 67834]]

Air Quality Planning and Standards, Research Triangle Park, NC, 
27711, in preparation.
    EPA, (1999b) Measuring Air Quality: The Pollutant Standards 
Index, Printing Management Office, U.S. Environmental Protection 
Agency, 401 M Street, SW, Washington, DC 20460, in preparation.

[FR Doc. 98-32571 Filed 12-8-98; 8:45 am]
BILLING CODE 6560-50-P