1. federal register
Wednesday
August 4, 1999
Part III
Environmental
Protection Agency
40 CFR Part 58
Air Quality Index Reporting; Final Rule

2. 42530 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations
ENVIRONMENTAL PROTECTION FOR FURTHER INFORMATION CONTACT: 214–4897, or sent by e-mail to
AGENCY Terence Fitz-Simons, EPA (MD–14), ball.michael@epa.gov.
Research Triangle Park, NC 27711, (1) Community Action Programs:
40 CFR Part 58 telephone (919) 541–0889, e-mail fitz- Blueprint for Program Design (EPA 420–
simons.terence@epa.gov. For health R–98–003).
[FRL–6409–7] effects information, contact Susan Lyon
Table of Contents
Stone, EPA (MD–15), Research Triangle
RIN 2060–AH92 I. Background
Park, NC 27711, telephone (919) 541–
1146, e-mail stone.susan@epa.gov. A. What Are the Legislative Requirements?
Air Quality Index Reporting B. What Is the History of the Air Quality
SUPPLEMENTARY INFORMATION: In
AGENCY: Environmental Protection Index?
compliance with President Clinton’s C. What Programs Are Related to the AQI?
Agency (EPA). June 1, 1998 Executive Memorandum on 1. Ozone and Particulate Matter NAAQS
ACTION: Final rule. Plain Language in government writing, Revisions
this package is written using plain 2. Real-Time Data Reporting Initiative
SUMMARY: Today, EPA adopts revisions language. Thus, the use of ‘‘we’’ or ‘‘us’’ (Ozone Mapping Project)
to the uniform air quality index used by in this package refers to EPA. The use 3. Community Action Programs
States for daily air quality reporting to of ‘‘you’’ refers to the reader and may II. Rationale for Final Revisions
the general public in accordance with include industry, State and local A. What Revisions Did We Propose?
section 319 of the Clean Air Act (Act). agencies, environmental groups and 1. What Were the Proposed General
These changes include the addition of Changes?
other interested individuals. 2. What Were the Proposed Changes to the
the following elements: a new category
Availability of Related Information Sub-Indices?
described as ‘‘unhealthy for sensitive B. What Were the Significant Comments
groups;’’ two new requirements, first, to Certain documents are available from and Our Responses?
report a pollutant-specific sensitive the U.S. Department of Commerce, 1. Comments and Responses on General
group statement when the index is National Technical Information Service, Changes
above 100, and second, to use specific 5285 Port Royal Road, Springfield, VA 2. Comments and Responses on Changes to
colors if the index is reported in a color 22161. Available documents include: the Sub-Indices
format; new breakpoints for the ozone (1) The Review of the National C. What Are the Final Revisions?
(03) sub-index in terms of 8-hour Ambient Air Quality Standards for 1. What Are the General Changes?
Ozone: Assessment of Scientific and 2. What Are the Changes to the Sub-
average 03 concentrations; a new sub-
Technical Information (‘‘Staff Paper’’) Indices?
index for fine particulate matter (PM2.5); D. What Are the Related Informational
and conforming changes to the sub- (EPA–452/R–96–007, June 1996, NTIS
Materials?
indices for coarse particulate matter # PB–96–203435, $67.00 paper copy and III. Regulatory and Environmental Impact
(PM10), carbon monoxide (CO), and $21.50 microfiche). (Add a $3.00 Analyses
sulfur dioxide (SO2). In addition, EPA is handling charge per order.) A. Executive Order 12866: OMB Review of
changing the name of the index from the (2) Review of the National Ambient ‘‘Significant Actions’’
Pollutant Standards Index (PSI) to the Air Quality Standards for Particulate B. Regulatory Flexibility Analysis/Small
Air Quality Index (AQI). This document Matter: Policy Assessment of Scientific Business Regulatory Enforcement
and Technical Information (‘‘Staff Fairness Act
discusses the development of related
Paper’’) (EPA–452/R–96–013, July 1996, C. Unfunded Mandates Reform Act
informational materials on pollutant- D. Paperwork Reduction Act
specific health effects and sensitive NTIS # PB–97–115406, $47.00 paper
E. Executive Order 13045: Children’s
groups and on precautionary actions copy and $19.50 microfiche). (Add a
Health
that can be taken by individuals to $3.00 handling charge per order.) F. Executive Order 12848: Environmental
reduce exposures of concern. This The guidance documents associated Justice
document also discusses the with this rulemaking are available from G. Executive Order 12875: Enhancing
interrelationship between the uniform EPA’s Office of Air Quality Planning Intergovernmental Partnerships
air quality index and other programs and Standards in Research Triangle H. Executive Order 13084: Consultation
that provide air quality information and Park, NC. Requests for these and Coordination with Indian Tribal
publications can be mailed to: Terence Governments
related health information to the general I. National Technology Transfer and
public, including State and local real- Fitz-Simons, EPA (MD–14), Research
Triangle Park, NC 27711. Your request Advancement Act
time air quality data mapping and J. Congressional Review Act
community action programs. may also be phoned in to Terence Fitz- IV. References
Simons at 919–541–0889, or sent by e-
EFFECTIVE DATE: October 4, 1999.
mail to fitz-simons.terence@epa.gov. I. Background
ADDRESSES: A docket containing (1) Guideline for Public Reporting of
information relating to EPA’s revisions A. What Are the Legislative
Daily Air Quality—Air Quality Index
of the air quality index (Docket No. A– Requirements?
(AQI) (EPA–454/R–99–010).
98–20) is available for public inspection (2) Guideline for Developing an Section 319 of the Act governs the
in the Air and Radiation Docket and Ozone Forecasting Program (EPA–454/ establishment of a uniform air quality
Information Center, U.S. Environmental R–99–009). index for reporting of air quality. This
Protection Agency, South Conference The following document is available section directs the Administrator to
Center, Room M–1500, 401 M St., SW, from EPA’s Office of Mobile Sources ‘‘promulgate regulations establishing an
Washington, DC 20460, telephone (202) (OMS) in Ann Arbor, MI. Requests for air quality monitoring system
260–7548. The docket may be inspected this publication can be mailed to: throughout the United States which
between 8 a.m. and 5:30 p.m. on Michael Ball, US EPA—National utilizes uniform air quality monitoring
weekdays, and a reasonable fee may be Vehicle and Fuel Emissions Laboratory criteria and methodology and measures
charged for copying. For the availability (NVFEL), 2000 Traverwood Dr., Ann such air quality according to a uniform
of related information, see Arbor, MI 48103. Your request may also air quality index’’ and ‘‘provides for
SUPPLEMENTARY INFORMATION. be phoned in to Michael Ball at 734– daily analysis and reporting of air

3. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42531
quality based upon such uniform air index values serve to divide the index broadening the ways in which State and
quality index * * *’’. into categories, with each category being local agencies can meet the nationally
identified by a simple informative uniform AQI reporting requirements,
B. What Is the History of the Air Quality
descriptor. The descriptors are intended and are contributing to State and local
Index?
to convey to the public information efforts to provide community health
In 1976, we established a nationally about how air quality within each protection and to attain or maintain
uniform AQI, called the Pollutant category relates to public health, with compliance with the NAAQS. We and
Standards Index (PSI), for use by State increasing public health concerns being State and local agencies recognize that
and local agencies on a voluntary basis conveyed as the categories range to the these programs are interrelated with
(41 FR 37660). This uniform index was upper end of the scale. Additional AQI reporting and with the information
established in light of a study conducted information about the general health on the effects of air pollution on public
by EPA and the President’s Council on effects associated with each category, health that is generated through the
Environmental Quality (CEQ, 1976). and precautions that sensitive groups periodic review, and revision when
This study found that the 55 urban areas and the general public can take to avoid appropriate, of the NAAQS.
in the U.S. and Canada reporting an exposures of concern, has been made
index of air quality used 14 different The most recent revisions to the O3
available through an informational and PM NAAQS, the Ozone Mapping
indices, in conjunction with different booklet, updated as appropriate, that
cautionary messages, such that in Project, and community action programs
also presents and explains the PSI (EPA,
essence 55 different indices were being are discussed briefly below. In light of
1994).
used to report air quality. This diversity the interrelationships among these
In 1979, we made changes to the AQI,
of indices sent a confusing message programs, we have developed today’s
in part to reflect revisions to the
about air quality to the public. Based in revisions to the uniform AQI with the
NAAQS for O3, and to establish
part on this study, we developed an goal of creating a revised AQI that can
requirements for AQI reporting (44 FR
index to meet the needs of State and effectively serve as a nationally uniform
27598). The requirement for State and
local agencies that has the following link across these programs. In so doing,
local agencies to report the AQI appears
advantages: it sends a clear and we intend to support and encourage
in 40 CFR part 58.50, and the specific
consistent message to the public by State and local participation in real-time
requirements (e.g., what to report, how
providing nationally uniform data reporting initiatives and the
to report, reporting frequency,
information on air quality; it is keyed as development and implementation of
calculations) are in appendix G to 40
appropriate to the national ambient air community action programs that serve
CFR part 58.
quality standards (NAAQS) and the public education and health protection
significant harm level (SHL) 1 which C. What Programs Are Related to the goals.
AQI?
have a scientific basis relating air 1. Ozone and Particulate Matter NAAQS
quality and public health; it is simple Historically, State and local agencies Revisions
and easily understood by the public; it have used primarily the AQI, or other
provides a framework for reflecting AQIs, to provide general information to On July 18, 1997, we revised the
changes to the NAAQS; and it can be the public about air quality and its primary NAAQS for O3 and PM based
forecasted to provide advance relationship to public health. In recent on a thorough review of the scientific
information on air quality. years, many States and local agencies, as evidence linking exposures to ambient
The PSI, which is also commonly well as EPA, have been developing new concentrations of these pollutants to
referred to by some State and local and innovative programs and initiatives adverse health effects at levels allowed
agencies as the AQI, includes sub- to provide more information to the by the previous NAAQS. In particular,
indices for O3, PM, CO, SO2, and public, in a more timely way. These we replaced the 1-hour O3 NAAQS with
nitrogen oxide (NO2), which relate initiatives, including real-time data an 8-hour O3 NAAQS and
ambient pollutant concentrations to reporting through the Ozone Mapping supplemented the PM NAAQS with 24-
index values on a scale from 0 through Project and community action programs, hour and annual standards for fine
500. This represents a very broad range can serve to provide useful, up-to-date, particulate matter (measured as PM2.5 3).
of air quality, from pristine air to air and timely information to the public These decisions were challenged in the
pollution levels that present imminent about air pollution and its effects. Such U.S. Court of Appeals for the District of
and substantial endangerment to the information will help individuals take Columbia Circuit, and on May 14, 1999,
public. The index has historically been actions to avoid or reduce exposures of the Court remanded them to the Agency
normalized across pollutants by concern and can encourage the public to for further consideration, principally in
defining an index value of 100 as the take actions that will reduce air light of constitutional concerns
numerical level of the short-term (i.e., pollution on days when levels are regarding section 109 of the Act as
averaging time of 24-hours or less) projected to be in air quality categories interpreted by EPA. American Trucking
primary NAAQS for each pollutant and of concern to local communities. Thus, Associations v. EPA, Nos. 97–1440, 97–
an index value of 500 as the SHL.2 Such these programs are significantly 1441 (D.C. Cir. May 14, 1999). On June
28, 1999, the U.S. Department of Justice
1 Significant harm levels are those ambient pollution, approaching the SHL, are in danger of on behalf of EPA filed a petition for
concentrations of air pollutants that present an being reached. Changes to this emergency episode rehearing seeking review of the Court’s
imminent and substantial endangerment to public program will be proposed in the near future.
health or welfare, or to the environment, as
decision by the entire Court of Appeals.
Below an index value of 100, historically an
established in 40 CFR 51.151. intermediate value of 50 was defined either as the The EPA is continuing to assess what
2 Intermediate index values of 200, 300, and 400 level of the annual standard if an annual standard further legal or administrative
were defined and are the basis for the Alert, has been established (for PM10 and SO2), or as a proceedings may be appropriate in
Warning, and Emergency episode levels included in concentration equal to one-half the value of the response to the Court’s decision, as well
40 CFR part 51, appendix L, as part of the short-term standard used to define an index value
Prevention of Air Pollution Emergency Episodes of 100 (for O3 and CO). Coarse or inhalable
program. This program requires specified areas to particulate matter, PM10, refers to particles with an 3 PM
2.5 refers to particles with an aerodynamic
have contingency plans in place and to implement aerodynamic diameter less than or equal to a diameter less than or equal to a nominal 2.5
these plans during episodes when high levels of air nominal 10 micrometers. micrometers.

4. 42532 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations
as its relevance to other rulemakings In this regard, the AQI is essentially a days above the numerical level of the
such as this one. way of conveying scientific/medical standards.
With respect to the present advice to the public in an easily These understandings were also
rulemaking, we have concluded that it understood form. reflected in CASAC’s advice to the
is appropriate to proceed with final As indicated below, there was broad Administrator during the O3 NAAQS
action on the proposed AQI revisions. support in public comments for review, urging expansion of the public
As indicated previously, section 319 of modifying and expanding the use of the health advisory system (i.e., a uniform
the Act requires the Agency to establish AQI to take into account the expanded AQI) and communication to the public
a uniform air quality index, and this understanding of air quality-health of the apparent nonthreshold nature of
requirement is independent of the relationships that resulted from EPA’s the health effects. More specifically, a
statutory provisions governing review of the latest scientific number of CASAC panel members
establishment and revision of the information on the effects of PM and O3. recommended ‘‘that an expanded air
NAAQS. Moreover, there is no statutory Other proposed revisions were designed pollution warning system be initiated so
requirement that the AQI be linked to to enhance the effectiveness of the AQI that sensitive individuals can take
the NAAQS, although EPA has used generally. The function the AQI serves appropriate ‘exposure avoidance’
NAAQS levels in the past as reference of conveying to the public information behavior’’ (Wolff, 1995). Consistent with
points for the establishment of specific on daily air quality and associated this advice, in the preamble to the
breakpoints within sub-indices. Nothing health risks is clearly important, and the proposed revisions to the O3 NAAQS
in the Court’s opinion alters the season of higher pollution levels is (61 FR 65733–65734), the Administrator
conclusions EPA reached in revising the imminent. For all the above reasons, we requested comment on the usefulness of
air quality criteria for PM and O3 under see no reason to delay final action on providing specific health effects
section 108 of the Act, or in the NAAQS the proposed revisions of the AQI. The information when ambient
rulemakings, concerning the occurrence remainder of this section discusses concentrations are around the numerical
of specific health effects at varying aspects of the O3 and PM NAAQS level of the standard, the
concentrations of PM and O3 in the air. rulemakings as they relate to today’s appropriateness of using the AQI to
Regardless of the outcome of the remand action. convey such information to the public,
as to the NAAQS themselves, we believe As a result of the reviews of the the possible addition of two new AQI
the scientific record and conclusions scientific information upon which the categories (one just above and one just
underlying them are more than 1997 NAAQS for O3 and PM are based, below the numerical level of the
sufficient as a basis for decisions on the an expanded understanding emerged as standard) and associated descriptors
levels at which the public should be to the nature of the relationships and levels, as well as related health
notified about health risks associated between exposure to ambient effects and cautionary statements.
with daily air quality.4 concentrations of these pollutants and Broad support for modifying the AQI
We do not regard this notification the health effects likely to be was received in public comments on
function as involving the constitutional experienced, especially near the level of this aspect of the O3 NAAQS proposal,
concerns raised in the Court’s opinion. the NAAQS. We and the Clean Air as discussed in the final rule
The AQI has no bearing on pollution Scientific Advisory Committee establishing revisions to the O3 NAAQS
control requirements for specific (CASAC) 5 recognized that for these (62 FR 38873–38874). Commenters
sources; nor does it serve to implement pollutants there may be no thresholds overwhelmingly endorsed expanding
the NAAQS involved in the litigation. below which health effects are not likely the use of the AQI for various reasons,
Rather, it provides information on air to occur, but rather a continuum of although many expressed concern with
quality and health that will help effects potentially extending down to the possible category descriptors
individual citizens take prudent, self- background levels. As ambient suggested in the proposal (i.e.,
protective actions to avoid or reduce concentrations increase, the proportion ‘‘moderately good’’ and ‘‘moderately
exposures of concern and to avoid of individuals likely to experience unhealthful’’). Many commenters felt
contributing to air pollution on days effects and the seriousness of the health that an expanded AQI could help
when unhealthy air quality is projected. effects increase. Thus, the 1997 particularly sensitive people take action
standards were not considered risk free. to minimize their exposures, and that
4 Under section 319, the levels that are While the standards were intended to the AQI could be combined with
appropriate for this purpose do not necessarily protect public health with an adequate community action programs to reduce
depend on the NAAQS levels that may be
appropriate under section 109. Depending on how
margin of safety, in accordance with ambient concentrations when the
the Agency chose to set an ambient standard, for section 109(b) of the Act, including the numerical level of the standard was
example, it might conclude that the standard does health of sensitive groups, exposures to forecasted to be exceeded. Some
not need to preclude certain effects falling below ambient concentrations just below the commenters endorsed increasing the
the level of public health concern, and at the same
time set the AQI in such a way as to assure that numerical level of the standards may specificity of health and cautionary
sensitive individuals who might experience those result in exposures of concern for the statements related to the AQI categories.
effects receive notification and advice on actions most sensitive individuals. Conversely, Commenters from State and local
they might take to avoid them. Similarly, AQI exposures to ambient concentrations
values might be set that are higher than the
agencies encouraged us to develop any
standard would permit but that would require more just above the numerical level of the approaches to revising the AQI in
serious health warnings. This is not to say, standards are not likely to result in consultation with them, specifically in
however, that the levels of the 1997 NAAQS are exposures of concern for most healthy the areas of sharing real-time monitoring
irrelevant to decisions on the AQI breakpoints. To people. This expanded understanding is
the contrary, the levels of the 1997 NAAQS are
data, risk communication with the
useful surrogates for a series of scientific
reflected in the forms of the new public, and coordination of a national
conclusions reached in the NAAQS rulemakings, standards, which allow for multiple program.
based on the revised air quality criteria, regarding
the nature, extent, and severity of health effects 5 CASAC is a scientific advisory committee 2. Real-time Data Reporting Initiative
associated with varying concentrations of PM and established under the Act to review the scientific (Ozone Mapping Project)
O3 in the air. Accordingly, later sections of this criteria and standards and to advise the
notice make reference as appropriate to relevant Administrator on revision of the NAAQS, as The Ozone Mapping Project is part of
levels of the 1997 NAAQS. appropriate. EPA’s Environmental Monitoring for

5. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42533
Public Access and Community Tracking they can protect their health and actions to the AQI being adopted today, together
(EMPACT) initiative—a new approach they can take to reduce pollution. with related informational materials,
to providing timely environmental will significantly improve the
3. Community Action Programs
information to communities. It is a effectiveness of communications with
cooperative effort of the EPA, State and The implementation of community these groups. Public education, or
local air pollution control agencies, and action programs (also referred to as programs directly targeting these
regional organizations including the voluntary action programs or episodic groups, may provide the most
Mid-Atlantic Regional Air Management emission control programs) is becoming significant benefits of a community
Association (MARAMA), the Northeast increasingly popular across the country action program. Forecasting days with
States for Coordinated Air Use as an innovative approach used to elevated pollution levels, and then
Management (NESCAUM), the northeast reduce emissions of O3 precursors, CO, communicating effectively about air
Ozone Transport Commission (OTC), and PM. Motivation for implementation quality and associated health effects,
the Lake Michigan Air Directors of this type of program often stems from may help these groups selectively limit
Consortium (LADCO), SouthEast States local government and business concerns their outdoor activities and, therefore,
Air Resource Managers (SESARM), and about the NAAQS attainment status of limit their potential for exposures of
Central States Air Resource Agencies the area and the restrictions, additional concern.
(CenSARA). During the summer of 1998, controls, and costs associated with We are committed to providing States
EPA’s Office of Air Quality Planning being classified as a nonattainment area. and local agencies with support in their
and Standards assumed coordination of Many areas are also motivated by public efforts to meet air quality standards, to
the project. health concerns and believe that inform the public about air quality, and
increasing the amount of air quality to educate the public about the impacts
The Ozone Map provides simple and
information available to sensitive of air pollution. The revisions to the
timely information about ground-level
populations raises awareness and AQI being adopted today have as a goal
O3. During the 1998 O3 season it was
results in significant health benefits. the creation of a revised AQI that can
available on EPA’s AIRNOW web site
Specific goals which are usually effectively serve as a nationally uniform
(http://www.epa.gov/airnow) and on
associated with community action link across the range of programs (e.g.,
some local television and news reports.
programs include: (1) Educate the real-time data reporting initiatives,
It is an animated contour map that
public and enhance protection of public community action programs) that have
shows concentrations of O3, in
health; (2) attain or maintain NAAQS these functions.
categories ranging from good to attainment status and the associated In support of community action
moderate to varying degrees of economic benefits; (3) meet specific programs, we have developed
unhealthy, based on AQI values, as they emission reduction targets; and (4) informational materials related to the
develop across the eastern United manage/reduce traffic congestion. AQI, including the health effects and
States. In 1998, the map was created Community action programs are cautionary statements associated with
from real-time, hourly O3 data provided usually voluntary and generally provide each category and more detailed health
by a network of more than 400 air multiple steps that the public, business, effects information (see section II.D.),
monitoring stations from South Carolina and industry can take to reduce available on the AIRNOW web site, that
to Wisconsin and Maine. When emissions when higher levels of air State and local agencies may use to
accessed on a computer, cautionary pollution are forecast to occur, enhance their community action
statements for each category could be including in particular transportation- programs. Focusing on transportation
displayed by running a cursor over the related measures such as trip reduction, measures that are often a major
legend. Also available on the AIRNOW postponement of certain activities such component of community action
web site were still maps of maximum as vehicle refueling, and maintenance of programs, EPA’s OMS has developed a
values and forecasted values, and cars. The programs emphasize educating report entitled, ‘‘Community Action
archived animated maps. In 1999, the the public about the impact of Programs: Blueprint for Program
ozone mapping coverage is being individual activities on local air quality Design.’’ This document describes the
expanded to include 31 States and over and the basics of air pollution. The major steps needed to put together a
1500 monitors across the eastern and educational component of these successful episodic control program and
central U.S., and California. In addition, programs also helps to create a strong provides criteria that State and local
TV weather service providers are link between environmental goals and agencies can use to examine and
planning to carry the Ozone Map and associated public health benefits. evaluate their own programs. The report
forecasts as part of their traditional Most of these programs are based on is available from OMS (see Availability
weather packages for local TV stations. the categories of the AQI and make use of Related Information).
Along with the Ozone Map, the of the AQI descriptors and related
AIRNOW web site contains information health effects and cautionary statements II. Rationale for Final Revisions
about O3 health effects in the ‘‘Health on action days. By linking action days In developing the revisions to the AQI
Facts’’ section, and emission reduction to the AQI, local control programs hope that are being adopted today, we sought
activities in the ‘‘What You Can Do’’ to alter individual behavior to reduce extensive input from State and local
section. It also provides links to real- emissions and to reduce exposures to agencies and from the public. We
time data, and community action the population. In addition to reduced sponsored a workshop with State and
program web sites, that are maintained pollutant exposure of the general local agencies, participated in numerous
by State and local agencies around the population due to improved air quality, meetings, prepared and made available
country. The goals of the web site are to: there are other health benefits directly a staff draft revision to the AQI sub-
(1) Provide real-time air pollution data associated with community action index for O3 for use during the 1998 O3
in an understandable, visual format, (2) programs that can be enhanced by season, and conducted several focus
provide information about the public linkage to the AQI. Different population groups across the nation to obtain
health and environmental effects of air groups are more sensitive to the harmful public input on the effectiveness of draft
pollution, and (3) provide the public effects of the different air pollutants revisions to the AQI and related O3
with information about ways in which included in the AQI, and the revisions maps and informational materials. A

6. 42534 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations
detailed history of the process leading to TABLE 1.—PROPOSED CATEGORY for members of sensitive groups is
the proposal and the rationale for the INDEX VALUES, DESCRIPTORS, AND entirely consistent with an original goal
proposed revisions are described more COLORS that the index be based on the
fully in the December 9, 1998 proposal relationships between pollutant
notice (63 FR 67818–67834). The sub- Index values Descriptor Color concentrations and adverse health
sections below contain a description of effects within various groups, e.g.,
the revisions we proposed, a discussion 0–50 ............. Good ................... Green aggravation of disease in people with
of the significant comments we received 51–100 ......... Moderate ............. Yellow respiratory disease and incidence of
101–150 ....... Unhealthy for sen- Orange respiratory effects in healthy people.
and our responses to them, and a
sitive groups.
summary of the AQI we are adopting Guidance on pollutant-specific
151–200 ....... Unhealthy ............ Red
today. 201–300 ....... Very unhealthy .... Purple cautionary statements related to the
301–500 ....... Hazardous ........... Maroon categories of the AQI is discussed below
A. What Revisions Did We Propose? in section II.D.
The primary consideration that These proposed changes reflected the Consistent with the overarching goal
shaped the proposed revisions was the addition of a new category above an AQI of national uniformity in the reporting
importance of providing nationally of 100, created by dividing the current of air quality, we proposed that the
uniform health information associated ‘‘unhealthful’’ category into two specific colors listed in Table 1 be
with daily ambient levels of the air categories. associated with each category. While the
pollutants included in the index, When air quality is in the ‘‘unhealthy AQI can be reported without the use of
consistent with the requirement of for sensitive groups’’ range, people that colors (through text and numbers alone),
section 319 of the Act for an index to are in the sensitive group, whether the when the index is reported using colors,
achieve national uniformity in daily air sensitivity is due to medical conditions, we proposed to require that only these
quality reporting. More specifically, the exposure conditions, or inherent specified colors be used. Three
proposed changes to the AQI sub- sensitivity, may experience exposures of examples of AQI reports that use color
indices for O3 and PM reflected the 1997 concern. However, exposures to ambient are the color bars that appear in many
revisions to the O3 and PM NAAQS. The concentrations in this range are not newspapers, the color scales on State
proposed general changes to the likely to result in exposures of concern and local agency web sites, and the
for most healthy people. The descriptor color contours of the Ozone Map. We
structure of the AQI were based on the
‘‘unhealthy for sensitive groups’’ was participated in many discussions with
expanded understanding that emerged
chosen to convey this message clearly. State and local agencies and
during the O3 and PM reviews as to the
Participants in focus groups (SAIC 1998) associations regarding which specific
nature of the relationships between
clearly understood that ‘‘sensitive colors should be associated with the
exposure to ambient concentrations of
groups’’ does not refer to the general AQI categories, particularly above an
these pollutants and the health effects
public, indicating that this descriptor index value of 100. These discussions
likely to be experienced, consideration
effectively communicates the intended typically were in the context of either
of the implications of changes for the
health message. This category would the Ozone Mapping Project or
other pollutants, and broad input from
include a caution that while perhaps of community action programs. It was
State and local agencies and the public.
interest to all citizens, would be of clear that the color associated with a
The proposed general changes to the particular interest to individuals and
AQI, together with related informational category can be part of the health effects
families of individuals who are and cautionary message being conveyed.
materials, were intended to expand the members of sensitive groups.
use of the AQI to provide more Were various State and local agencies to
As air quality moves into the use different colors to represent the
pollutant-specific health information, ‘‘unhealthy’’ range, exposures are same category, and thus the same level
especially when ambient concentrations associated with an increase in the of air quality, it could well send a
are close to the level of the primary number of individuals who could confusing message about air quality and
NAAQS. potentially experience effects and associated health effects to the public.
1. What Were the Proposed General includes a greater proportion of
As an alternative to requiring the use
Changes? members of the general public. Based on
of specified colors, we solicited
input received in the development of
comment on the option of
a. Categories and related descriptors, the proposal, the descriptor
recommending, rather than requiring,
index values and colors. The AQI ‘‘unhealthy’’ appropriately characterizes
the use of these colors when reporting
currently incorporates the pollutants O3, air quality in this range.
agencies choose to report the AQI in
PM, CO, SO2, and NO2. Index values In addition to an increasing number of
color format. In soliciting comment on
range from 0 to 500 6, and the index is exposures of concern, when air quality
this alternative, we sought to allow
segmented into five categories named by moves into the ‘‘unhealthy’’ range and
communities maximum flexibility in
descriptor words that were chosen to above, individuals who were affected at
AQI reporting, while still preserving a
characterize the relationship between lower levels, typically members of
nationally uniform AQI. We, therefore,
daily air quality and public health. To sensitive groups, are likely to
requested that commenters addressing
reflect better the current understanding experience more serious health effects
this issue discuss how this more flexible
of the health effects associated with than members of the general public. To
approach would satisfy the statutory
exposure to these air pollutants, we reflect this understanding, it is
language requiring a nationally uniform
proposed to revise the AQI categories appropriate to convey two messages in
AQI if different colors may be used
and descriptors, and to associate the cautionary statements for both the
across the nation to represent the same
specific colors with the categories as ‘‘unhealthy’’ and ‘‘very unhealthy’’
range of air quality.
shown below in Table 1. categories. One message is directed to
members of sensitive groups, and the b. Reporting requirements. We
6 For NO , the index ranges from 200 to 500, since other is directed to the general public. proposed to change 40 CFR part 58.50
2
there is no short-term NAAQS for this pollutant. The use of a distinct cautionary message to require reporting of the AQI in all

7. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42535
Metropolitan Statistical Areas (MSAs) 7 at-risk from different pollutants, issuing forecasted O3 concentrations. Since we
with a population over 350,000, instead advisories for all sensitive groups who have determined that forecasting would
of all urbanized areas with a population may be affected at AQI values greater add much to the benefits of AQI
over 200,000. This change was proposed than 100 clearly improves public health reporting, we indicated that we would
for consistency with the other protection. Therefore, the proposed rule be making available guidance on
monitoring regulations in part 58, which encouraged, but did not require, that starting a forecasting program (EPA
are or will be based on MSAs. This AQI reports include: appropriate health 1999b) in an area or MSA where
proposed change would not, however, effects and cautionary statements, all forecasting is not presently done.
have a significant impact on who is AQI values greater than 100, the AQI for Included in the document is guidance
required to report, since virtually the sub-divisions of the MSA (if there are on using hourly O3 concentrations as
same number of cities would be covered important differences in air quality predictors for 8-hour averages.
under the proposed reporting across sub-divisions of the MSA), c. Index name. Many State and local
requirement as are covered under the possible causes for high index values, agencies encouraged us to change the
existing requirement. and the actual pollutant concentrations. name of the PSI to the Air Quality
Consistent with early input from State These topics were also discussed in our Index, or AQI, since many agencies
and local agencies, we proposed to draft ‘‘Guideline for Public Reporting of already use the name AQI when
change the rounding conventions used Daily Air Quality—Pollutant Standards reporting the AQI value to the public.
to calculate index values corresponding Index (PSI)’’ that was made available on Most participants in the focus groups
to pollutant concentrations at and above the AIRLINKS web site. preferred the name AQI, commenting
the numerical level of the NAAQS to be The proposed rule emphasized the that it more clearly identified the index
consistent with the rounding importance of forecasting the AQI by as relating to the quality of the air rather
conventions used in defining the specifying that forecasted values should than to environmental pollution in
NAAQS for each pollutant. This would be reported, when possible, but did not general. Based on these considerations,
avoid situations where a health advisory require that forecasted values be we solicited comment on changing the
could be issued that describes the air as reported. Given the importance of the index name from Pollutant Standards
unhealthy, when in fact the numerical O3 sub-index in a large number of Index (PSI) to Air Quality Index (AQI).
level of the standard has not been MSAs, and the use of an 8-hour
exceeded. 2. What Were the Proposed Changes to
averaging time for calculating the O3
The proposed rule retained the the Sub-Indices?
sub-index value, forecasting the O3
requirements to identify the area for index value is now more beneficial than To conform to the proposed general
which the AQI is being reported, the before. For a health advisory system to changes to the AQI discussed above,
time period covered by the report, the be effective, people need to be notified and to reflect the recent revisions to the
‘‘critical’’ pollutant for which the as early as possible to be able to avoid O3 and PM NAAQS, we proposed
reported AQI value was derived, the exposures of concern. Because the O3 changes to the sub-indices for O3, PM,
AQI value, and the associated category sub-index is based on 8-hour O3 CO, and SO2; no conforming changes are
descriptor. Recognizing that many averages, forecasting O3 concentrations necessary for the NO2 sub-index. The
agencies use a color format to report the clearly would have increased value in proposed sub-indices are summarized
AQI, the proposed rule added the providing cautionary statements to the below in Table 2, in terms of pollutant
requirement to report the associated public. We recognized that many State concentrations that correspond to
category color if a color format is used. and local air agencies are already breakpoints in the index, and are
Because different sensitive groups are issuing health advisories based on discussed in the following sections.
TABLE 2.—PROPOSED BREAKPOINTS FOR O3, PM2.5, PM10, CO, AND SO2 SUB-INDICES
O3 PM
AQI value CO, 8-hr SO2, 24-hr
PM2.5, 24-hr PM10, 24-hr (ppm) (ppm)
8-hr (ppm) 1-hr (ppm) (µg/m3) (µg/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 be revised accordingly.
a. Proposed ozone sub-index. On July hour average O3 concentrations protection to the public, especially
18, 1997, we revised the O3 primary measured at each monitor within an children active outdoors and other
NAAQS to replace the 1-hour standard area (62 FR 38856–38896). These sensitive groups, against a wide range of
with a new standard with an 8-hour proposed revisions were based on O3-induced health effects, including
average at a level of 0.08 ppm and a findings from the most recent review of decreased lung function; increased
form based on the 3-year average of the the NAAQS indicating that the new respiratory symptoms; hospital
annual fourth-highest daily maximum 8- primary standard will provide increased admissions and emergency room visits
7 A complete list of MSAs and their boundaries
can be found in the Statistical Abstract of the
United States (1998).

8. 42536 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations
for respiratory causes, among children average) (62 FR 38652–38760). These PM2.5 concentration to be associated
and adults with pre-existing respiratory revisions were based on findings from with a PM2.5 index value of 500 suggest
disease such as asthma; inflammation of the most recent review of the PM a continuum of effects in this range,
the lung; and possible long-term damage NAAQS that recently published studies with increasing PM2.5 concentrations
to the lungs. In setting this standard, we have indicated that serious health being associated with increasingly larger
recognized that there is no apparent effects were more closely associated numbers of people likely experiencing
threshold below which health effects do with the levels of the smaller particle serious health effects (62 FR 38675; Staff
not occur, that the standard is not risk subset of PM10. These health effects Paper, p. VII–27). The proposed
free, and, thus, that exposures of include premature mortality and generally linear relationship between
concern are possible below the increased hospital admissions and AQI values and PM2.5 concentrations in
numerical level of the standard for some emergency room visits, primarily in the this range, rounded to increments of 50
extremely sensitive individuals. elderly and individuals with µg/m3 to reflect the approximate nature
We proposed to set an index value of cardiopulmonary disease; increased of such a relationship, is consistent with
100 equal to the level of the 8-hour O3 respiratory symptoms and disease in this evidence.
standard. Recognizing the continuum of children and individuals with Proposed conforming changes to the
health effects, we considered the results cardiopulmonary disease; decreased PM10 sub-index. Consistent with the
of a quantitative risk assessment lung function, particularly in children retention of the levels of the PM10
(Whitfield et al., 1996) in selecting 8- and individuals with asthma; and NAAQS, we proposed to retain the PM10
hour O3 concentrations to correspond to alterations in respiratory tract defense sub-index generally and to add a new
index values of 50, 150 and 200. Since mechanisms. In addition, PM10 breakpoint at an index value of 150 to
no human health effects information standards were retained at the same conform to the proposed additional AQI
was available for 8-hour average O3 levels of 50 µg/m3 (annual) and 150 µg/ category. We proposed that this
concentrations at significantly higher m3 (24-hour average) to continue to breakpoint be set at a PM10 24-hour
levels, we proposed to retain the provide protection against health effects average concentration of 250 µg/m3, the
breakpoints at the upper end of the AQI associated with the coarse particle mid-point between the breakpoints
scale (between the ‘‘very unhealthy’’ subset of PM10, including aggravation of associated with index values of 100 and
and ‘‘hazardous’’ categories and the SHL asthma and respiratory infections. To 200. We believe that the PM10 sub-
which corresponds to the top of the PSI reflect these revisions to the PM index, with this conforming change,
scale of 500) in terms of the existing 1- NAAQS, we proposed to add a new sub- remains appropriate for the public
hour average concentrations. index for PM2.5, and to make conforming health protection purposes of the AQI.
These proposed revisions reflect the changes to the sub-index for PM10, c. Proposed conforming changes to
new 8-hour O3 NAAQS and will in consistent with the proposed general the CO and SO2 sub-indices. Since the
almost all areas result in a more changes to the AQI. The proposed sub- current AQI sub-indices reflect the
precautionary index than the current 1- indices are summarized in Table 2 and current NAAQS for CO and SO2, the
hour sub-index. However, we discussed below. only change we proposed for these sub-
recognized that a very small number of Proposed new PM2.5 sub-index. indices was to add a breakpoint to each
areas in the U.S. have atypical air Consistent with the historical method of sub-index at an index value of 150 to
quality patterns, with very high 1-hour selecting breakpoints of the AQI, we conform to the proposed additional AQI
daily peak O3 concentrations relative to proposed to set an index value of 100 category. We proposed that these
the associated 8-hour average at the level of the 24-hour PM2.5 breakpoints be set at concentrations at
concentrations. In such areas, the use of NAAQS, 65 µg/m3, and an index value the mid-points between the breakpoints
the current 1-hour sub-index may be of 50 at the level of the annual NAAQS, associated with index values of 100 and
more precautionary on a given day than 15 µg/m3. Also consistent with the basic 200, consistent with the approach
the proposed 8-hour sub-index. To structure of the AQI, the proposed described above for conforming changes
allow for the reporting of the more upper bound index value of 500 to both the 1-hour O3 sub-index and the
precautionary sub-index value, we corresponds to the SHL, established in PM10 sub-index. These proposed
proposed to retain the 1-hour sub-index section 51.16 of the CFR under the breakpoints are summarized in Table 2
at and above AQI values of 100 and to Prevention of Air Pollution Emergency and will be reviewed in conjunction
allow the reporting of the higher of the Episodes program. The SHL is set at a with the future reviews of the CO and
two O3 sub-index values. Thus, both the level that represents an imminent and SO2 NAAQS.
new 8-hour and the current 1-hour sub- substantial endangerment to public
indices, as shown in Table 2, were health. When we propose revisions to B. What Were the Significant Comments
included in the proposed appendix G. the Prevention of Air Pollution and Our Responses?
Since for the large majority of areas the Emergency Episodes program, the This section describes the significant
8-hour sub-index will be more proposal will include a SHL for PM2.5. comments we received on proposed
precautionary, we did not propose to In the interim, we proposed to establish revisions to the index and our general
require all areas to calculate both sub- a PM2.5 concentration of 500 µg/m3 to be responses to them. More detailed
index values. Rather, we proposed to associated with a PM2.5 index value of comment summaries and responses are
allow areas the flexibility to calculate 500. contained in a Response to Comments
both sub-index values and, when both For intermediate breakpoints in the Document that is available in the docket
sub-index values are calculated, to AQI between values of 100 and 500, (see ADDRESSES).
require that the higher value be PM2.5 concentrations were proposed
reported. We specifically solicited that generally reflect a linear 1. Comments and Responses on General
comment on this proposed approach. relationship between increasing index Changes
b. Proposed PM sub-index. On July values and increasing PM2.5 values. The a. Categories and related descriptors,
18, 1997, we revised the PM NAAQS by available scientific evidence of health index values and colors. With regard to
adding a new set of standards for fine effects related to population exposures the proposed changes to the general
particles, or PM2.5, set at levels of 15 µg/ to PM2.5 concentrations between the 24- structure of the index, we received
m3 (annual) and 65 µg/m3 (24-hour hour NAAQS level and the proposed comments that focused on two major

9. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42537
issues. The first major issue was air pollution warning system (to) be initiated public. As noted by one State
whether to add a category above or so that sensitive individuals can take commenter:
below the standard, or both. In addition, appropriate exposure avoidance behavior,’’
however EPA has misrepresented the health We are satisfied and support the proposed
related to that issue were comments category index values, descriptors and colors.
threat with the levels it has proposed.
about the proposed descriptor for the (Docket No. A–98–20, IV–D–17). [We] believe that the Air Quality Index * * *
category we proposed to add above the has been a very effective communication tool
level of the standard. The second major A State commenter that supported during the ozone season. It has been our
issue regarded the particular colors, adding a category below the level of the experience that a category above the standard
listed in Table 1, we proposed to standard observed that adding such a provides the proper communication to the
affected populations without alarming or
associate with each category. category would be consistent with desensitizing others. (Docket No. A–98–20,
With regard to the general structure of EPA’s conclusion ‘‘that exposures to IV–G–04).
the index, most commenters supported ambient concentrations just below the
our proposal to add a category above the numerical level of the standard may Further, given the changes we have
level of the standard. However, result in exposures of concern for the made to the PM2.5 sub-index, and the
commenters from environmental groups most sensitive individuals.’’ (Docket No. expanded ‘‘moderate’’ range and the
and several States suggested adding a A–98–20, IV–D–19). cautionary statements we have made
category below the level of the standard available in guidance for use below the
We understand and agree with the
to provide additional caution for level of the 8-hour O3 standard, we do
issues related to communication of risk
members of sensitive groups, instead of, not believe a category below the level of
below the levels of the 24-hour PM2.5 the standard to caution members of
or in addition to one above. These and 8-hour O3 standards. For the PM2.5
commenters expressed the view that the sensitive groups would be an
sub-index, we have addressed concerns appropriate distinction for any of the
proposed sub-indices, that added a about health effects below the level of
category above the standard, did not pollutants included in the index. We
the 24-hour PM2.5 standard by revising believe that the approach we have
sufficiently caution members of the PM2.5 sub-index so sensitive groups
sensitive groups about health effects adopted retains the simplicity of the
are cautioned below the 24-hour PM2.5 index while allowing for more detailed
occurring below the level of the standard. Based on review of the
standard. Specifically, their comments cautionary information to be made
suggested revisions to the PM2.5 sub- available to the public when
were in reference only to potential index that we received in comments, we
health effects occurring below the 8- appropriate.
believe this approach fully addresses With regard to the descriptor
hour O3 and 24-hour PM2.5 standards. their concerns. The revision is
Regarding health effects below the PM2.5 ‘‘unhealthy for sensitive groups,’’ some
discussed in section II.B.2 below. commenters expressed the view that
standard, one State commenter took
For better communication of health this descriptor is misleading because it
exception with the statement in the
risk below the 8-hour O3 standard, we encompasses a large segment of the
proposal that an additional category
have addressed the issues raised by population. In addition, they argued, the
below the standard, while perhaps
commenters by revising the O3 sub- public will not know that for certain
meaningful for O3, would not be an
index. We have expanded the pollutants healthy people, especially
appropriate distinction for the other
‘‘moderate’’ range of the 8-hour O3 sub- healthy children, are members of
pollutants in the index. This commenter
index to make it more precautionary. sensitive groups. Noting that it is
noted that ‘‘such a distinction would be
When air quality is in the ‘‘moderate’’ prudent policy to assume that most risk
more imperative for other pollutants,
range of the 8-hour O3 sub-index, we communication regarding air quality
especially for PM where the level of the
have provided health effects and impacts will be limited to the general
24-hour standard may be less protective
cautionary statements, available in our descriptors, some of these commenters
of sensitive groups than the ozone
AQI Reporting Guidance document requested that if we continue to
standard.’’ (Docket No. A–98–20, IV–D–
(EPA, 1999a) (discussed in section II.D), distinguish sensitive groups from the
19). Agreeing with the importance of
that may be used by State and local general population, that the descriptor
cautioning sensitive groups below the
agencies to caution unusually sensitive be changed from ‘‘unhealthy for
level of the 24-hour PM2.5 standard,
individuals below the level of the 8- sensitive groups’’ to ‘‘unhealthy for
another commenter noted ‘‘We believe
hour O3 standard. This revision is children and other sensitive groups,’’ so
that adding a category below the level
discussed in section II.B.2 below. that the public would receive a clear
of the standard is of particular
importance with respect to fine We do not believe it is necessary or message that children are members of a
particles.’’ (Docket No. A–98–20, IV–D– appropriate to change the general sensitive group that may be at increased
11). Regarding the O3 sub-index, some structure of the index by adding a new risk from exposure to ozone. (Docket
of the States and the environmental category below the level of the standard No. A–98–20, IV–D–2, IV–D–4 and IV–
groups that endorsed adding a category to caution extremely sensitive D–11). We agree with the view of these
below the level of the standard individuals. Based on the concerns of commenters, based on the responses of
supported that position by noting that State and local agencies that the participants in the focus groups, that the
we and CASAC stated that extremely addition of two new categories would public will not know that healthy
sensitive individuals may be affected unduly complicate the index, we are people, including healthy children, may
down to background levels of O3. One adding just one new category to be at risk when air quality is in the
comment from an environmental group maintain the degree of simplicity ‘‘unhealthy for sensitive groups’’ range.
noted that: strongly supported by State and local The suggested descriptor, however, is
agencies, none of whom advocated the only appropriate for pollutants for
The CASAC recognized that for O3 and fine addition of two new categories. As which children are a sensitive group.
particle pollution, ‘‘there are no discernible described in section II.A.1 above, we Since the sensitive groups differ from
thresholds below which health effects are not
likely to occur in the most sensitive believe that adding a category above the one pollutant to another, and children
individuals’ as it was advising EPA to set level of the standard makes a distinction are only part of the sensitive group for
new health standards. We agree with CASAC that is useful for members of sensitive O3, PM2.5 and NO2, this descriptor is not
and support the idea of setting ‘‘an expanded groups without alarming the general appropriate for the other pollutants. For

10. 42538 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations
example, the descriptor ‘‘unhealthy for the same or a similar color scheme below the level of the standard, as
children and other sensitive groups’’ noted that it effectively and described above.
would not be appropriate for use in the appropriately portrayed the full range of In considering these comments, we
CO sub-index, where people with heart local air quality values. On the other recognize that the NAAQS are set to
disease are the group most at-risk. Use hand, some environmental groups and protect public health with an adequate
of this descriptor when CO levels are several States commented that the color margin of safety, including the health of
above an index value of 100 could lead red should be used for the category just sensitive groups. When the standards
to confusion about the health effects above standard, instead of the color are met, public health is protected.
associated with high levels of CO. orange that we proposed. Primarily, Exposures to ambient concentrations
Therefore, we do not believe it would be these commenters expressed the view just above the numerical level of the
useful or prudent to adopt the that the color orange would not send a standards are not likely to result in
descriptor ‘‘unhealthy for children and sufficiently strong message that the exposures of concern for most healthy
other sensitive groups.’’ To increase standard has been exceeded. In the people. This is especially true for the 8-
public awareness that healthy children proposal we indicated that because the hour O3 standard, which has a
are members of the sensitive group for color red sends a strong cautionary concentration-based form designed to
O3, we are adding the requirement that message, it is most appropriately used offer more protection from higher
when the AQI value is above 100, when effects are likely to occur in the concentrations than from multiple
reporting agencies include in their general population, and when more smaller exceedances of the standard.
published report a statement describing serious effects are likely in members of The form of the 8-hour O3 standard
the sensitive group for that particular sensitive groups. Many of these allows for multiple days above the level
pollutant. The reporting requirement for commenters noted that since up to 30 of the standard, provided the 3-year
pollutant-specific statements describing percent of the population could be average of the fourth-highest maximum
sensitive groups is discussed below in considered to be in the sensitive group concentrations does not exceed the level
section II.C.1.b on reporting for O3, when the standard is exceeded of the standard. This means that public
requirements, and listed in appendix G. the general public should be alerted. health is protected, even when there are
We believe that the requirement for These commenters expressed the view multiple days each year when ambient
agencies to report the pollutant-specific that it is appropriate to use the color red O3 concentrations are above the level of
statements identifying the groups at just above the level of the standard both the standard, as long as the standard is
risk, when air quality is above an index to alert the public of potential health met. Therefore, it is inappropriate on
value of 100, will more effectively risks and to encourage emission any given day to express a high level of
communicate the risk associated with reduction actions. An environmental concern when air quality just exceeds
specific air pollutants, and thereby group commented: the level of the standard. Besides
better help members of the public While individuals that are sensitive to poor sending an inaccurate health effects
reduce personal exposure. To the extent air quality may look at the daily listing in the message by using the color red with the
possible with AQI reporting, this newspaper or call a message recorded by the category ‘‘unhealthy for sensitive
requirement will also ensure that the state or local air agency, we know from groups,’’ another concern is the
public is informed that children are part experience that air quality does not receive potential loss of credibility that could
of the sensitive group for O3. This broad public attention until it is predicted or result from repeatedly sending a signal
requirement will not only improve reaches the level of ‘‘code red.’’ At that point, disproportionate to the expected
protection for healthy children, but also the television and radio media announces incidence of noticeable symptoms. If
that people should restrict outdoor activity
healthy adults, the elderly, and people this were to happen, the AQI could lose
and take steps to not add more pollution to
with heart and lung disease. We believe the air by carpooling, using less electricity, the power to influence people’s
that another good way to address this or using mass transit. (Docket No. A–98–20, behavior to protect their health. One
lack of awareness is to educate the IV-D–17). commenter from a State agency
public, and the media and health care expressed this concern:
Another commenter from a State
professionals that inform the public, One of our key concerns * * * is that the
agency noted:
about the health effects message general public will become ambivalent if we
associated with the category ‘‘unhealthy Considering that the definition of sensitive forecasted 20, 30, or more Code Red days
for sensitive groups.’’ To help individuals for ozone includes healthy active over the course of an ozone season. Under
children and outdoor workers, a clear this scenario, people may not take adequate
accomplish the goal of educating the
unambiguous message needs to be sent to the precautions to protect themselves when an
public, we will be expanding the public so that they can respond accordingly. actual unhealthy level is reached. (Docket
development of education and outreach For parents of active children, a message No. A–98–20, IV–G–05).
materials and activities as described in which states that air quality is unhealthy,
section II.D below. and displays it using the color red, sends a A commenter from another State
clear message—even though it may carry agency expressed a similar view:
With regard to the colors listed in
Table 1, we received comments with it the risk that individuals not in the It is important to make sure that this
sensitive population might also take general message is not jeopardized by
concerning both the particular colors
exposure avoidance measures. Issuing a treating the new 85 ppb, 8-hour standard as
associated with the different categories message that air quality is unhealthy for the bright line between healthy and
and whether specific colors should be sensitive individuals and displays it with a unhealthy. The Code Red message will not be
required or recommended. The majority code orange runs the risk of having sensitive considered credible if it is issued between 40
of commenters, including most State individuals, or those guiding sensitive to 60 times a summer in our area. Last year
and local agencies commenting, individuals (i.e., doctors and parents) not there were 54 days * * * where the 8-hour
supported our proposed color scheme. prescribe any avoidance action because of the standard was exceeded. (Docket No. A–98–
Many of those (commenters that did ambiguity of the message. (Docket No. A–98– 20, IV–G–13).
support it), had used the same or a 20, IV-G–19). From the comments we have received
similar color scheme associated with Additionally, these commenters and from our focus group research, we
either community action programs or suggested that the color orange be used believe that the color red sends too
ozone maps. Commenters that had used for the category they wanted us to add strong a message for use in the