area of the country.  This is the basis for allowing Regional
Administrators the authority to use their discretion to require
additional monitors.  The process by which an Regional Administrator
would use this authority usually is part of a collaborative process with
state agencies.  Typically, Regional Administrators will work with state
and local agencies to design and/or maintain the most appropriate NO2
network to service the needs for a given area.  For all the situations
proposed where a Regional Administrator may require additional
monitoring, EPA expects that Regional Administrators would work on a
case-by-case basis in requiring any additional monitors.  One example
might be a location impacted by a stationary source where the required
near-road NO2 monitor site is not the location of maximum hourly
concentration in a CBSA. As a result, that location could be the
location of expected maximum concentration in the area.  This situation
could arise due to impacts from one of or a combination of multiple
sources that could include point, area, and non-road source emissions in
addition to on-road mobile source emissions. Alternatively, in this
example, if the sources responsible for this situation are producing
more widespread impacts on a community or area, the Regional
Administrator may require an area-wide monitor to assess population
exposures, or support other monitor objectives served by area-wide
monitors such as photochemical pollutant assessment or pollutant
forecasting.  Another example might be in a CBSA where a state or local
agency is fulfilling its minimum monitoring requirements near-road
monitors, but an additional location is identified where near-road
population exposure exists, at concentrations near or above the NAAQS,
that is unique, relative to the minimally required near-road monitor
locations.  For this example, the unique situation might be due to the
particular population or community that is affected, or the differences
in fleet mix, congestion patterns, terrain, or geographic area, relative
to any minimally required monitoring site(s) in that area.

EPA recognizes that a variety of exposures scenarios can occur in an
area, and we believe that Regional Administrators should have the
discretion to require additional monitoring if such a unique situation
is recognized in an area.  In such situations, the actual locations
where additional monitoring could be required would likely have already
been identified by state or EPA Regional staff through data analysis,
such as the evaluation of existing ambient data and/or emissions data,
or through air quality modeling. Such information may indicate that an
area might have ground-level NO2 concentrations that may exceed the
NAAQS, and that a there is potential for population exposure to those
concentrations.

c.	Conclusions on Regional Administrator Authority

Due to the fact that EPA recognizes that a nationally applied monitoring
network may not always provide the intended monitoring coverage due to
case-by-case type situations, we are finalizing, as proposed, that (1)
Regional Administrators shall have the discretion to require monitoring
above the minimum requirements as necessary to address situations where
the required near-road monitors do not represent a location or locations
where the expected maximum hourly NO2 concentrations exist in a CBSA.
(2) Regional Administrators shall have the discretion to require
additional near-road monitoring sites to address situations where
minimum monitoring requirements are not sufficient to meet monitoring
objectives, such as a situation where there is a variety of exposure
potential in an area due to variety in the amount or types of fleet mix,
congestion patterns, terrain, or geographic areas within a CBSA.  (3)
Regional Administrators shall have the discretion to require additional
area-wide NO2 monitoring sites above the minimum monitoring requirements
where the minimum monitoring requirements for area-wide monitors are not
sufficient to meet monitoring objectives.  In any case where a Regional
Administrator might be in a position to use their authority to require
additional monitoring, EPA expects that the state and the Regional
Administrator would work together to evaluate evidence that suggests an
area may warrant additional monitoring.  EPA also notes that if
additional monitoring should be required, the state would present
information on any potential new sites through its Annual Monitoring
Network Plan, as required by 40 CFR §58.10, which includes a
requirement for public inspection or comment, and approval by the EPA
Regional Administrator.

5.	Monitoring Network Implementation

The following paragraphs provide background, rationale, and details for
the final changes to the approach for the monitoring network
implementation.

a.	Proposed Monitoring Network Implementation Approach

	EPA proposed that state and, when appropriate, local air monitoring
agencies provide a plan for deploying monitors in accordance with the
proposed network design by July 1, 2011.  EPA also proposed that the
proposed NO2 network be physically established no later than January 1,
2013

b.	Comments

	Most environmental and public health group commenters made comments
that suggested EPA change the implementation date from the proposed
January 1, 2013 to a date that would require the minimally required NO2
network deployed sooner than proposed.  Most states and state group
commenters, along with industry group commenters, recommended that EPA
keep the network implementation date as January 1, 2013, or move it
later than proposed.  Some of the commenters who suggested moving it
later noted that issues with monitoring site identification, site
development, and overall lack of experience working in the near-road
environment would make implementation difficult under the proposed
implementation deadline.

EPA recognizes that a lot of work must occur to deploy the two-tier
network design by the January 1, 2013 date.  We recognize the need for
guidance and  plan to aid state agencies in the network implementation
process, particularly through guidance documentation that will be
developed.  EPA agrees with the suggestion by NACAA that the CASAC
Ambient Air Monitoring Methods subcommittee should be consulted as part
of any guidance development for near-road monitoring.  Further, EPA
believes that collaboration with the states and state groups in
developing guidance will be highly beneficial to the implementation
process.  This would allow for those states that do have increased
experience in near-road monitoring to lend to guidance development and
provide a conduit for sharing experiences amongst all stakeholders.

In perspective, EPA believes that the approximate 2 years and 11 months
between promulgation of this rulemaking and the mandated January 1, 2013
network implementation date include extra time relative to what was
traditionally allowed for network implementation following rulemakings
such as this.  Additionally, we note that are being cognizant of the
time needed to collect complete data that would allow data from the
two-tier network to be considered in the next NO2 NAAQS review.  EPA
would need to have data from 2013, 2014, and 2015 to have a chance to
include data in the next NAAQS review since it is intended to be
performed on a 5-year cycle.  Finally, delaying the installation of the
minimally required monitors, particularly the near-road NO2 sites, will
also delay the acquisition of the three years of data that are needed to
use in determining attainment, which, as noted in XX of this document,
would not occur until 2017, at the earliest.

c.	Conclusions on Monitoring Network Implementation

	We are finalizing the date by which state and, when appropriate, local
air monitoring agencies shall establish the required NO2 monitoring
network as January 1, 2013, as was proposed.  We believe that the
allotted time for implementation will allow for the development of
guidance documentation, particularly allowing for interactions with
CASAC and NACAA, and for the processes that will be involved in
deploying this network, including the assessment of road segments in
CBSAs, identifying and working with local transportation officials as
needed on issues regarding access and safety, and the exchange of
information and feedback on potential sites with EPA, prior to any
commitment to any sites in an annual monitoring plan. However, based on
feedback received through public comments, and to allow for more time to
process guidance information, to carry out the previously mentioned
deployment processes, and to allow for information exchanges to occur,
we are changing the date by which state and, when appropriate, local air
monitoring agencies shall provide a plan for deploying monitors in
accordance with required network design from July 1, 2011 to July 1,
2012. However, EPA encourages states and local air agencies to supply as
much information as possible on the NO2 sites they may be considering,
or have possibly selected, to satisfy the minimum NO2 network monitoring
requirements in their Annual Monitoring Network Plan submitted July 1,
2011.

6.	Near-road Site Selection

The following paragraphs provide background, rationale, and details for
the final changes to the approach and criteria by which required
near-road sites shall be selected.

a.	Proposed Near-road Site Selection Criterion

EPA proposed that minimally required near-road NO2 monitoring stations
shall be selected by ranking all road segments within a CBSA by AADT and
then identifying a location or locations adjacent to those highest
ranked road segments where maximum hourly NO2 concentrations are
expected to be highest and siting criteria (discussed below) can be met
in accordance with that proposed for 40 CFR Part 58 Appendix E. Where a
state or local air monitoring agency identifies multiple acceptable
candidate sites where maximum hourly NO2 concentrations are expected to
occur, the monitoring agency should consider taking into account the
potential for population exposure in the criteria utilized to select the
final site location. Where one CBSA is required to have two near-road
NO2 monitoring stations, we proposed that the sites shall be
differentiated from each other by one or more of the following factors:
fleet mix; congestion patterns; terrain; geographic area within the
CBSA; or different route, interstate, or freeway designation.

b.	Comments

	EPA received many comments from CASAC, public health groups, states and
state groups, and industry groups on the proposed procedure by which
states will select near-road sites.  CASAC, along with some health group
and state commenters noted that interpreted proposed language to intend
that states should select a site near the road with the highest ranked
AADT possible, without considering other factors.  For example, one
CASAC panel member noted that siting monitors based on traffic counts
alone might miss locations where maximum NO2 concentrations would occur.
They proceeded to recommend the use of modeling to assist in the site
selection process.  In another example, the ALA, EDJ, EJ, and NRDC,
stated that “Near-road monitor placement should be determined not only
by the highest AADT volumes in a given CBSA, but also by the highest
heavy-duty truck volumes.”  In one more example, in NACAA statements
they make a comment about “…basing monitor locations on the annual
average daily traffic (AADT) without regard to vehicle mix or dispersion
characteristics…”.

EPA does not intend for AADT counts to be the sole reason a near-road
site is selected.  As noted earlier in paragraph 2(b) of this section,
there is a general relationship between AADT and mobile source
pollution, where higher traffic counts correspond to higher mobile
source emissions.  The use of AADT counts is intended to be a mechanism
by which the locations of expected maximum NO2 concentrations due to
mobile sources are identified.  EPA notes that there other factors that
can influence which road segment in a CBSA may be the actual location
where the maximum NO2 concentrations might occur.  These factors include
vehicle fleet mix, roadway design, congestion patterns, terrain, and
meteorology.  When states identify their top-ranked road segments by
AADT, EPA intends for states to evaluate all of the factors listed above
that influence where the location of expected maximum NO2 concentration
may occur from the pool of candidate target road segments and monitoring
sties. As a result of the comments on this interpretation of the
proposal, EPA will specifically list the factors that will be used
considered by states in their site selection process once a state has
identified the most heavily trafficked roads in a CBSA via AADT counts.
In addition, these same factors were proposed to be considered by states
who are required to place two near-road monitors in one CBSA.  EPA
maintains that these factors will be key to differentiate the two
monitoring sites from each other, providing further characterization of
near-road environments in larger urban areas that are more likely to
have a greater number of major roads across a potentially larger
geographic area, and a corresponding increase in potential for exposure
in different settings.

	EPA received comments from some state and industry commenters (e.g.
Iowa, NY DEC, Edison Electric, and Savannah River Nuclear Solutions) who
suggested that population exposure should be a first-level consideration
in the near-road monitoring site selection, instead of a second-level
consideration which EPA proposed it to be.

EPA notes that the intent of the revised primary NO2 NAAQS is to protect
against the maximum allowable NO2 concentration anywhere in an area,
which includes ambient air on and around roads, which would limit
exposures to peak NO2 concentrations, across locations and over time,
with a relatively high degree of confidence.  We also note the
agency’s historical practice of locating monitors in locations of
maximum concentration, at the appropriate spatial scale, so long as the
monitor is characterizing ambient air.  If EPA were to allow population,
population density, or another population weighted metric to influence
where near-road monitors are located, it is possible that the required
near-road monitors in a CBSA would not be where the location of expected
maximum NO2 concentration, due to mobile sources, would occur.  By
monitoring in the location of expected maximum 1-hour concentrations,
near-road monitoring sites will likely represent the highest NO2
concentrations in an area directly attributable to mobile sources or a
group of sources that includes mobile sources.  EPA agrees that
population should not be ignored, however, which is reflected in the
rule language as it was proposed that says that if a states  identifies
multiple acceptable candidate sites where maximum hourly NO2
concentrations are expected to occur, the monitoring agency should
consider taking into account the potential for population exposure in
the criteria utilized to select the final site location.

	EPA received commenters from [NEED PUBLIC COMMENTER ID] who suggested
that near-road monitoring site selection should take into consideration
the location of other major mobile and point sources for NO2 emissions,
such as airports, seaports, and power plants.  Further, some of these
commenters also suggested that state and local agencies have increased
flexibility in determining the appropriate balance between locating
near-road monitors along the busiest roadways, areas most likely to have
the highest NO2 concentrations, and diverse types of roadways.

EPA agrees that other major NO2 sources that have the potential to
violate the NAAQS should be monitored.  The issue is whether such
monitoring should be handled through a more inclusive set of minimum
requirements or whether case-by-case treatment is appropriate.  EPA
believes that any of these mobile sources and any stationary source that
may be causing ground-level NO2 concentrations that are near or above
the NAAQS are able to be monitored through a requirement by the Regional
Administrator (discussed above) or possibly through state and local
initiative.  The reason that Regional Administrators have discretion to
require additional monitors is to provide the ability to deal with
situations where other locations in an area might warrant monitoring,
which EPA believes was the root of the respondent’s comment.

	One state commenter, the Wisconsin Department of Natural Resources,
requested that the term “major road” be defined and also requested
clarification on what “top-ranked” means with regard to AADT counts
on road segments.  The term “major road” is widely used in
literature and can be found to be defined differently from one
scientific study to another.  In this document and the proposal, EPA
simply means for “major road” to be synonymous with a road that is
relatively heavily trafficked.  EPA also does not believe it is
appropriate to define whether “top-ranked” means, for example, 5%,
10%, or 15%, of all road segments, as this would be arbitrary.  Each
CBSA will have a different distribution of total road segments and
corresponding AADT counts on those segments.  The intent of the
requirement to rank all road segments by AADT counts and select a site,
considering the other local factors noted above, near a “top-ranked”
road segment is to focus attention on the most heavily trafficked roads,
around which there is higher potential for maximum NO2 concentrations to
occur.

c.	Conclusions on Near-road Site Selection

	We are finalizing the near-road site selection criteria as proposed,
and are clarifying the original intent that the selection criteria
include the consideration of localized factors. As a result, minimally
required near-road NO2 monitoring stations shall be selected by ranking
all road segments within a CBSA by AADT and then identifying a location
or locations adjacent to those highest ranked road segments, considering
fleet mix, roadway design, congestion patterns, terrain, and
meteorology, where maximum hourly NO2 concentrations are expected to be
highest and siting criteria can be met in accordance with 40 CFR Part 58
Appendix E.  As was noted in the network implementation section above,
EPA will work with states to assist with the near-road site selection
process through the development of guidance material and through
information exchanges amongst the air monitoring community.

	We are also finalizing the requirement, as proposed, that when one CBSA
is required to have two near-road NO2 monitoring stations, the sites
shall be differentiated from each other by one or more of the following
factors: fleet mix; congestion patterns; terrain; geographic area within
the CBSA; or different route, interstate, or freeway designation, as was
proposed.

7.	Near-road Siting Criteria

The following paragraphs provide background, rationale, and details for
the final changes to the siting criteria for required near-road
monitoring sites.

a.	Proposed Near-road Siting Criteria

We proposed that near-road NO2 monitoring stations must be sited so that
the NO2 monitor probe is no greater than 50 meters away, horizontally,
from the outside nearest edge of the traffic lanes of the target road
segment, and shall have no obstructions in the fetch between the monitor
probe and roadway traffic such as noise barriers or vegetation higher
than the monitor probe height. We solicited comment on whether the
near-road sites should be located on the predominantly downwind side of
the target roadways.

We proposed that the monitor probe be located within 2 to 7 meters above
the ground, as is required for microscale PM2.5 sites.  We also proposed
that monitor probe placement on noise barriers or buildings, where the
inlet probe height is no less than 2 meters and no more than 7 meters
above the target road, will be acceptable, so long as the inlet probe is
at least 1 meter vertically or horizontally away (in the direction of
the target road) from any supporting wall or structure, and the
subsequent residence time of the pollutant in the sample line between
the inlet probe and the analyzer does not exceed 20 seconds.

b.	Comments

	EPA received many comments state (e.g. LIST) and industry groups (e.g.
LIST) indicating that the near-road network poses significant safety
issues and a related need for increased logistical flexibility for
installing a monitoring site. [INSERT QUOTE HERE].

EPA notes that in all instances of field work, safety is a top priority.
 EPA believes that there are various ways to install near-road sites
while ensuring worker and traffic safety, and that safety is an
important part of the logistical considerations that states should
account for when selecting and installing near-road sites.  An example
of a step that could be taken to alleviate safety concerns might be
purposefully placing a monitoring site behind existing barriers like
guardrails and fencing, or possibly by installing a short distance of
such barriers to protect the site workers, site infrastructure, and
nearby traffic.  In addition to intentional measures that can be taken
to enhance safety, EPA notes that the 50m distance proposed is wide
enough to accommodate a sites that would satisfy many setback provisions
that exist for private or commercial building permits near roads, and
may be viewed as a confirmation that our proposed siting criteria are
safely attainable.

	Many commenters suggested that the allowable maximum distance a
near-road monitoring probe can be from the target road be increased from
50 meters to something wider, such as 200 meters.  Conversely, there
were some commenters who suggested that EPA reduce the allowable
distance to as close as 30 meters to the target road.  EPA believes that
increasing the allowable distance above 50 meters would compromise the
intent of near-road monitoring.  As was noted in the proposal language,
scientific literature indicates that on-road, mobile source derived NO2
exhibits a peak concentration on or very near the source road, and those
concentrations decay over a variable but relatively short distance back
to near area-wide or background (upwind of the target road)
concentrations.  Literature values indicate that the distance required
for NO2 concentrations to return to near area-wide or background
concentrations away from major roadways can range up to 500 meters. The
actual distance is variable, and highly dependent on topography,
roadside features, meteorology, and the related photochemical reactivity
conditions (Baldauf et al., 2008; Beckerman et al., 2007; Clements et
al., 2008; Gilbert et al. 2003; Hagler et al., 2009; Rodes and Holland,
1980; Singer et al., 2003; Zhou and Levy, 2007).  Therefore, monitor
probe placement at increasing distances from a road, such as 200 meters,
will correspondingly decrease the potential for sampling maximum
concentrations of NO2 due to the traffic on the target road.  Baldauf et
al. (2009) indicate that monitoring probes would ideally be situated
between 10 and 20 meters from the nearest traffic lane for near-road
pollutant monitoring.

Having received comments suggesting widening and shortening the
allowable distance that an NO2 monitor probe may be from the target
road, EPA believes the proposed allowable distance a near-road NO2 probe
can be from the target road of 50 meters provides enough flexibility for
site placement while not sacrificing the potential to actually monitor
the peak NO2 concentrations.  However, in light of the information
provided here on how NO2 peak concentrations can decay over relatively
short distances, EPA encourages states to place near-road sites as close
as safely possible to target roads to increase the probability of
measuring the peak NO2 concentrations that occur in the near-road
environment, again noting that Baldauf et al. (2009) indicate that
monitor probes would ideally be situated between 10 and 20 meters from
the nearest traffic lane for near-road pollutant monitoring.

EPA received several comments on the solicitation for comment on
requiring near-road monitoring sites to be placed on the downwind side
of the target road where the commenters encouraged such a requirement.
Conversely, other commenters suggested that such a requirement is
unnecessary, with one commenting that siting monitors in downwind
locations would not be feasible for all locations and that EPA should
allow upwind monitoring so long as upwind monitors are used in
conjunction with air dispersion modeling.  EPA noted in its proposal
that research literature indicates that in certain cases, mobile source
derived pollutant concentrations, including NO2, can be detected upwind
of roads, above background levels, due to a phenomenon called upwind
meandering.  Kalthoff et al. (2007) indicates that mobile source derived
pollutants can meander upwind on the order of tens of meters, mainly due
to vehicle induced turbulence, while Beckerman et al. (2008) note that
near-road pollutant concentrations on the predominantly upwind side of
their study sites dropped off to near background levels within the first
50 meters, but were above background in this short and variable upwind
range, which could be due, at least in part, to vehicle induced
turbulence.  This upwind meandering characteristic of pollutants in the
near-road environment provides an additional basis for locating
near-road sites within 50 meters of target road segments, but also
reduces the absolute need to be downwind of the road.  EPA believes that
very few, if any, near-road sites would be able to be situated in a
location that was always downwind.  For example, a hypothetical site may
have winds routinely out of several different cardinal directions
throughout the year, without one being a dominant direction. As a
result, for some period of a year, and given the variability
meteorology, some period of a day, or even an hour, the near-road site
may not be downwind of the target road, no matter which side of the road
its on.  EPA is not going to finalize a requirement that near-road sites
must be climatologically downwind of the target road segment because of
the additional limitations this introduces to finding potential site
candidates in exchange for what may be a small increase in the
opportunity to monitor peak NO2 concentrations.  However, EPA encourages
states to place monitors in the climatologically downwind direction
whenever possible, in an attempt to measure the peak NO2 concentrations
more often than not.

EPA proposed that required near-road NO2 monitor probes be located
within 2 to 7 meters above the ground, as is required for microscale
PM2.5 sites.  Two commenters commented that monitor probes distributed
across the range of 2 to 7 meters may generate variability in
concentrations from site to site.  One of those two went further to
suggest that the allowable height range be reduced to 2.5 to 3.5 meters
above the ground.  Another group of commenters commented that the 2 to 7
meter range may not be practical for many sites and suggested guidelines
for alternate siting requirements. Finally, another group of commenters
commented that “the lower end of the proposed height of 2 to 7 meters
appears to capture the highest NO2 concentrations, and more accurately
represents human exposure at the breathing zone.”  In the proposal,
EPA noted that near-road monitoring sites will be adjacent to a variety
of road types, where some target roads will be on an even plane with the
monitoring station, while others may be cut roads (i.e., below the plane
of the monitoring station) or fill and open elevated roads (i.e., where
the road plane is above the monitoring station). EPA noted in the
proposal that it is appropriate to place the NO2 monitor probe as close
to the plane of the target road segment as possible, while staying
between 2 to 7 meters above the ground.  An allowable range between 2
and 7 meters provides more flexibility in site installation, which EPA
considers important because of the variety of siting situations each
state may have to deal with for each individual site.  While EPA agrees
that tighter allowable range such as 2.5 to 3.5 meters would reduce site
to site variability and keep probes nearer the “breathing zone” as
it was commented, the wider range of 2 to 7 meters is still appropriate.
EPA encourages states, where possible, to have monitor probes closer to
the suggested heights of 2.5 to 3.5 meters, while also attempting to
keep monitor probes as close to the plane of the target road as
possible.

In the proposal, EPA proposed in the siting criteria language that the
subsequent residence time of the pollutant in the sample line between
the inlet probe and the analyzer can not exceed 20 seconds.  EPA
received two comments regarding guidelines for maximum allowable inlet
length and sample residence time.  EPA notes that in 40 CFR Part 58
Appendix E, paragraph (9)(c), it is written that sample probes for
reactive gas analyzers at NCore monitoring sites must have a sample
residence time less than 20 seconds.  EPA believes this rule is also
appropriate for NO2 monitors, particularly if a monitor inlet manifold
is extended away from the main monitoring shelter. EPA also notes that
this concept was proposed in the proposal preamble language, but was
omitted from the proposed regulation text.  The final version of the
regulation text will have the revised language for this requirement in
40 CFR Part 58 Appendix E, paragraph (9)(c).

c.	Conclusions on Near-road Siting Criteria

We are finalizing the near-road NO2 monitor siting criteria, as
proposed, where (1) required near-road NO2 monitor probes shall be as
near as practicable to the outside nearest edge of the traffic lanes of
the target road segment; but shall not be located at a distance greater
than 50 meters, in the horizontal, from the outside nearest edge of the
traffic lanes of the target road segment, (2) required near-road NO2
monitor probes shall have an unobstructed air flow, where no obstacles
exist at or above the height of the monitor probe, between the monitor
probe and the outside nearest edge of the traffic lanes of the target
road segment, (3) required near-road NO2 monitors are required to have
sampler inlets between 2 and 7 meters above ground level, and (4)
residence time of NO2 in the sample line between the inlet probe and the
analyzer does not exceed 20 seconds.

8.	Area-wide Monitor Site Selection and Siting Criteria

The following paragraphs provide background, rationale, and details for
the final changes to the site selection and monitor siting criteria for
required area-wide monitoring sites.

a.	Proposed Area-wide Monitor Site Selection and Siting Criteria

	EPA proposed that sites required as part of the second tier of the NO2
monitoring network design, known as the area-wide monitoring component,
be sited to characterize the highest expected NO2 concentrations at the
neighborhood and larger (area-wide) spatial scales in a CBSA.

b.	Comments

	While many commenters made comment supporting area-wide monitoring in
regard to the adoption of the alternative area-wide network design in
lieu of the proposed approach, only a relative few made comments that
related to the actual sites and siting criteria.  Of those comments
related to the siting of area-wide monitors, one respondent noted that
they should be located at least 1,000 meters away from any major roads
or intersections to ensure that the concentration of NO2 measured is
representative of an area-wide concentration instead of peak near-road
concentrations.  EPA notes that in order for an NO2 monitoring site to
be classified as a neighborhood (or larger) spatial scale site, it must
meet the roadway set-back requirements in Table E-1 of 40 CFR Part 58
Appendix E.  EPA believes that this existing set-back table is
appropriate to use to ensure that any NO2 site that may be intended to
be an area-wide site will be sufficiently distanced from any major road.

c.	Conclusions on Area-wide Monitor Site Selection and Siting Criteria

	We are finalizing the requirement that any sites required as part of
the second tier of the NO2 monitoring network design, known as the
area-wide monitoring component, be sited to characterize the highest
expected NO2 concentrations at the neighborhood and larger (area-wide)
spatial scales in a CBSA.

9.	Meteorological Measurements

The following paragraphs provide background, rationale, and details for
the final changes to the requirement of meteorological monitoring at
near-road monitoring sites.

a.	Proposed Meteorological Measurements

	In further support of characterizing the peak NO2 concentrations
occurring in the near-road environment, EPA proposed to require
three-dimensional anemometry, providing wind vector data in the
horizontal and vertical planes, along with temperature and relative
humidity measurements, at all required near-road monitoring sites.

b.	Comments

	EPA received comments from several states (e.g. LIST) that did not
support the proposed meteorological measurement requirements.  They
noted issues with siting the probe nearer to structures and to the
ground than is typically done and averaging periods were called into
question.  One respondent commented that the recording of air turbulence
data at near-road monitoring stations ought to be encouraged but not
required.  As a result, EPA will not require meteorological monitoring
at near-road NO2 monitoring stations, but encourages states to do some
form of meteorological monitoring to better inform the conditions in
which they are acquiring NO2 data.  At a minimum, basic anemometry data
would be useful in identifying whether the site is upwind, downwind, or
otherwise oriented, relative to the target road.

c.	Conclusions on Meteorological Measurements

	We are not finalizing the proposal to require three-dimensional
anemometry, providing wind vector data in the horizontal and vertical
planes, along with temperature and relative humidity measurements, at
all required near-road monitoring sites.

C.	Data Reporting

The following paragraphs provide background, rationale, and details for
the final changes to the data reporting requirements, data quality
objectives, and measurement uncertainty.

1.	Proposed Data Quality Objectives and Measurement Uncertainty

In the proposal, EPA noted that state and local monitoring agencies are
required to report hourly NO, NO2, and NOx data to AQS within 90 days of
the end of each calendar quarter. We also noted that many agencies also
voluntarily report their pre-validated data on an hourly basis to
EPA’s real time AIRNow data system, where the data may be used by air
quality forecasters to assist in ozone forecasting. We believe these
data reporting procedures are appropriate to support the revised primary
NO2 NAAQS.

EPA proposed to develop data quality objectives (DQOs) for the proposed
NO2 network.  We proposed a goal for acceptable measurement uncertainty
for NO2 methods to be defined for precision as an upper 90 percent
confidence limit for the coefficient of variation (CV) of 15 percent and
for bias as an upper 95 percent confidence limit for the absolute bias
of 15 percent.

2.	Comments

	EPA received no substantive comments that disagreed with the proposed
language on data reporting, the data quality objectives, or goals for
measurement uncertainty.

3.	Conclusions on Data Quality Objectives and Measurement Uncertainty

	We are finalizing the approach to develop data quality objectives, and
the proposed goal for measurement uncertainty, as proposed.

IV. 	Appendix S--Interpretation of the Primary NAAQS for Oxides of
Nitrogen and Revisions to the Exceptional Events Rule

	The EPA proposed to add Appendix S, Interpretation of the Primary
National Ambient Air Quality Standards for Oxides of Nitrogen, to 40 CFR
part 50 in order to provide data handling procedures for the proposed
NO2 1-hour primary standard and for the existing NO2 annual primary
standard.  The proposed Appendix S detailed the computations necessary
for determining when the proposed 1-hour and existing annual primary NO2
NAAQS are met. The proposed Appendix S also addressed data reporting,
data completeness considerations, and rounding conventions.

	Two versions of Appendix S were proposed. The first applied to a 1-hour
primary standard based on the annual 4th high value form, while the
second applied to a 1-hour primary standard based on the 99th percentile
daily value form.

	The final version of Appendix S is printed at the end of this notice
and applies to an annual primary standard and a 1-hour primary standard
based on the 98th percentile daily value form.  Appendix S is based on
the near-roadway approach to the setting the level of the 1-hour
standard and to siting monitors.  As such, these versions place no
geographical restrictions on which monitoring sites’ concentration
data can and will be compared to the 1-hour standard when making
nonattainment determinations and other findings related to attainment or
violation of the standard.

	The EPA is amending and moving the provisions of 40 CFR 50.11 related
to data completeness for the existing annual primary standard to the new
Appendix S, and adding provisions for the proposed 1-hour primary
standard.  Substantively, the data handling procedures for the annual
primary standard in Appendix S are the same as the existing provisions
in 40 CFR 50.11 for that standard, except for an addition of a
cross-reference to the Exceptional Events Rule, the addition of
Administrator discretion to consider otherwise incomplete data complete,
and the addition of a provision addressing the possibility of there
being multiple NO2 monitors at one site.  The procedures for the 1-hour
primary standard are entirely new.

	The EPA is also making NO2-specific changes to the deadlines, in 40 CFR
50.14, by which States must flag ambient air data that they believe have
been affected by exceptional events and submit initial descriptions of
those events, and the deadlines by which States must submit detailed
justifications to support the exclusion of that data from EPA
determinations of attainment or nonattainment with the NAAQS. The
deadlines now contained in 40 CFR 50.14 are generic, and are not always
appropriate for NO2 given the anticipated schedule for the designations
of areas under the final NO2 NAAQS.

	The purpose of a data interpretation appendix in general is to provide
the practical details on how to make a comparison between multi-day and
possibly multi-monitor ambient air concentration data and the level of
the NAAQS, so that determinations of compliance and violation are as
objective as possible. Data interpretation guidelines also provide
criteria for determining whether there are sufficient data to make a
NAAQS level comparison at all.  The regulatory language for the
pre-existing annual NO2 NAAQS, originally adopted in 1977, contained
data interpretation instructions only for the issue of data
completeness. This situation contrasts with the situations for ozone,
PM2.5, PM10, and most recently Pb for which there are detailed data
interpretation appendices in 40 CFR part 50 addressing more issues that
can arise in comparing monitoring data to the NAAQS.

A.	Interpretation of the primary NAAQS for oxides of nitrogen for the
annual primary standard

	The purpose of a data interpretation rule for the NO2  NAAQS is to give
effect to the form, level, averaging time, and indicator specified in
the regulatory text at 40 CFR 50.11, anticipating and resolving in
advance various future situations that could occur. Appendix S provides
common definitions and requirements that apply to both the annual and
the 1-hour primary standards for NO2. The common requirements concern
how ambient data are to be reported, what ambient data are to be
considered (including the issue of which of multiple monitors’ data
sets will be used when more than one monitor has operated at a site),
and the applicability of the Exceptional Events Rule to the primary NO2
NAAQS.

	The proposed Appendix S also addressed several issues in ways which are
specific to the individual primary NO2 standards, as described below.

1.	Proposed interpretation of the annual standard

	The proposed data interpretation provisions for the annual standard are
consistent with the pre-existing instructions included along with the
statement of the level and form of the standard in 40 CFR 50.11.  These
are the following:  (1) At least 75% of the hours in the year must have
reported concentration data. (2) The available hourly data are
arithmetically averaged, and then rounded (not truncated) to whole parts
per billion. (3) The design value is this rounded annual average
concentration.  (4) The design value is compared with the level of the
annual primary standard (expressed in parts per billion).

	In the proposal, EPA noted that it would be possible to introduce
additional steps for the annual primary standard which in principle
could make the design value a more reliable indicator of actual annual
average concentration in cases where some monitoring data have been
lost.  For example, averaging within a calendar quarter first and then
averaging across quarters could help compensate for uneven data capture
across the year. For some aspects of the data interpretation procedures
for some other pollutants, the current data interpretation appendices do
contain such additional steps. The proposed provisions for the proposed
1-hour NO2 standard also incorporated some such features.

2.	Comments on interpretation of the annual standard

	We received four comments, all from state agencies, on data
interpretation for the annual NO2 standard.  Of the four commenters, two
recommended the use of a weighted annual mean to appropriately implement
the annual primary standard.  Two other commenters asserted that there
is no strong seasonality in NO2 concentrations, and that therefore there
is no need to use a weighted annual mean or to require data completeness
quarter-by-quarter.

3.	Conclusions on interpretation of the annual standard

Upon investigating the issue of NO2 seasonality using data from AQS as
part of considering the comments, we have found that there are notable
variations in quarterly mean NO2 concentrations.  It is therefore quite
possible that an unweighted annual mean calculated without a
quarter-by-quarter data completeness requirement might not represent the
true annual mean as well as a weighted annual mean calculated with a
quarter-by-quarter completeness requirement. However, the current
practice of requiring 75% completeness of all of the hours in the year
and calculating the annual mean without weighting has been retained in
the final rule, because of its simplicity and because we believe it will
not interfere with effective implementation of the annual NAAQS.  No
area presently is nonattainment for or comes close to violating the
annual standard.  Therefore, the choice between the two approaches can
only have a practical effect, if any, on whether at some time in the
future an area is determined to be newly violating the annual standard.
 If a monitor has a complete and valid design value below the standard
using the unweighted mean approach (with only an annual data
completeness requirement) but the design value would be considered
incomplete and invalid under a hypothetical weighted mean approach (with
a quarterly completeness requirement), the monitor would in either case
be considered not to be violating and its data would not be the basis
for a nonattainment designation.  If a monitor has a design value above
the standard using the unweighted annual mean approach but is incomplete
with respect to a hypothetical quarterly completeness requirement, then
the two approaches would have different implications for the
determination of a violation.  A quarterly completeness requirement
would make a finding of violation impossible, unless the Administrator
chose to treat the data as if complete under another provision of the
final rule. The unweighted annual mean approach would allow but not
force a finding of violation, because the Administrator will have
discretion to make any such findings because there will be no mandatory
round of designations for the annual standard given that the annual
standard has not been revised in this review.  The Administrator will be
able to consider the representativeness of the unweighted annual mean
when deciding whether to make a discretionary nonattainment
redesignation.  Given that the annual standard requires only one year of
monitoring data for the calculation of a design value, little time will
be lost if the Administrator chooses to work with a state to obtain a
new design value based on more complete and/or seasonally balanced
monitoring data.

B.	Interpretation of the primary NAAQS for oxides of nitrogen 1-hour
primary standard

1.	Proposed interpretation of the 1-hour standard

	With regard to data completeness for the 1-hour primary standard with a
4th highest daily value form, the proposed Appendix followed past EPA
practice for other NAAQS pollutants by requiring that in general at
least 75% of the monitoring data that should have resulted from
following the planned monitoring schedule in a period must be available
for the key air quality statistic from that period to be considered
valid. For the 1-hour primary NO2 NAAQS, the key air quality statistics
are the daily maximum 1-hour concentrations in three successive years.
It is important that sampling within a day encompass the period when
concentrations are likely to be highest and that all seasons of the year
are well represented.  Hence, the 75% requirement was proposed to be
applied at the daily and quarterly levels.

	Recognizing that there may be years with incomplete data, the proposed
text provided that a design value derived from incomplete data would
nevertheless be considered valid in either of two situations.

	First, if the design value calculated from at least four days of
monitoring observations in each of these years exceeds the level of the
1-hour primary standard, it would be valid.  This situation could arise
if monitoring was intermittent but high NO2 levels were measured on
enough hours and days for the mean of the three annual 4th high values
to exceed the standard.  In this situation, more complete monitoring
could not possibly have indicated that the standard was actually met.

	Second, we proposed a diagnostic data substitution test which was
intended to identify those cases with incomplete data in which it
nevertheless is very likely, if not virtually certain, that the daily
1-hour design value would have been observed to be below the level of
the NAAQS if monitoring data had been minimally complete.

	It should be noted that one possible outcome of applying the proposed
substitution test is that a year with incomplete data may nevertheless
be determined to not have a valid design value and thus to be unusable
in making 1-hour primary NAAQS compliance determinations for that 3-year
period.

	Also, we proposed that the Administrator have general discretion to use
incomplete data based on case-specific factors, either at the request of
a state or at her own initiative.  Similar provisions exist already for
some other NAAQS.

	The second version of the proposed Appendix S contained proposed
interpretation procedures for a 1-hour primary standard based on the
99th percentile daily value form.  The 4th high daily value form and the
99th percentile daily value form would yield the same design value in a
situation in which every hour and day of the year has reported
monitoring data, since the 99th percentile of 365 daily values is the
4th highest value.  However, the two forms diverge if data completeness
is 82% or less, because in that case the 99th percentile value is the
3rd highest (or higher) value, to compensate for the lack of monitoring
data on days when concentrations could also have been high.

	Logically, provisions to address possible data incompleteness under the
99th percentile daily value form should be somewhat different from those
for the 4th highest form.  With a 4th highest form, incompleteness
should not invalidate a design value that exceeds the standard, for
reasons explained above. With the 99th percentile form, however, a
design value exceeding the standard stemming from incomplete data should
not automatically be considered valid, because concentrations on the
unmonitored days could have been relatively low, such that the actual
99th percentile value for the year could have been lower, and the design
value could have been below the standard.  The second proposed version
of Appendix S accordingly had somewhat different provisions for dealing
with data incompleteness.  One difference was the addition of another
diagnostic test based on data substitution, which in some cases can
validate a design value based on incomplete data that exceeds the
standard.

	The second version of the proposed Appendix S provided a table for
determining which day’s maximum 1-hour concentration will be used as
the 99th percentile concentration for the year.  The proposed table is
similar to one used now for the 24-hour PM2.5 NAAQS, which is based on a
 98th percentile form, but adjusted to reflect a 99th percentile form
for the 1-hour primary NO2 standard.  The proposed Appendix S also
provided instructions for rounding (not truncating) the average of three
annual 99th percentile hourly concentrations before comparison to the
level of the primary NAAQS.

2.	Comments on interpretation of the 1-hour standard

	Three commenters expressed the view that the 75% completion per quarter
requirement should apply with respect to the 1-hour standard.  A fourth
commenter recommended that the requirement be increased to 82%.  Another
person commented that the requirement of 75% of the hours in a day is
too stringent.  The commenter noted that it would be inappropriate not
to count the day if the maximum concentration observed in the hours
measured is sufficiently high to make a difference with regard to
compliance with the NAAQS.  A comment was received that the substitution
test should not be included, on the grounds that nonattainment should
not be declared without irrefutable proof. This commenters also said
that the same completeness requirement as used for nonattainment should
be used for attainment.  We received one comment that the computation of
design values where multiple monitors are present at a site should be
averaged and not taken from a designated primary monitor.

3.	Conclusions on interpretation of the 1-hour standard

	Consistent with the Administrator’s decision to adopt a 98th
percentile form for the 1-hour NAAQS, the final version of Appendix S is
based on that form. Table 1 has been revised from the version that was
proposed, so that it results in the selection of the 98th percentile
value rather than the 99th percentile value.

	We agree with the three comments expressing the view that the
requirement for 75% data completeness per quarter should apply with
respect to the 1-hour standard.  A fourth comment recommended that the
requirement be increased to 82%.  We believe 82% is too stringent
because of the number of monitors that would not achieve such a
requirement and we believe that 75% captures the season.  We agree that
an incomplete day should be counted if  the maximum concentration
observed in the hours measured is sufficiently high to make a difference
with regard to compliance with the NAAQS, and we have accounted for that
in section 3.2.c.i by validating the design value if it is above the
level of the primary 1-hour standard when at least 75 percent of the
days in each quarter have at least one reported hourly value.  We agree
that substitution should not be used for the establishment of
attainment/nonattainment.  The commenter who remarked on this issue
appears not to have understood that the specific proposed substitution
tests have essentially zero probability of making a clean area fail the
NAAQS, or vice versa, because the substituted values are chosen to be
conservative against such an outcome. As noted in section 3.2(c)(i),
when substitution is used, the 3-year design value based on the data
actually reported, not the ‘‘test design value’’, shall be used
as the valid design value.

	In the course of considering the above comment regarding data
substitution tests to be used in cases of data incompleteness, EPA has
realized that there could be some cases of data incompleteness in which
the proposed procedure for calculating the 1-hour design value might
result in an in appropriately low design value.  As proposed, only days
with measurements for at least 75% of the hours in the day would be
considered in any way when identifying the 99th percentile value (99th
for purposes of the adopted NAAQS).  However, there could be individual
hours in other, incompletely monitored days that had measured
concentrations higher than the identified 98th percentile value from the
complete days. It would be inappropriate not to consider those hours and
days in some way. However, if all days with at least one hourly
concentration were used to identify the 99th percentile value without
any regard to their incompleteness, this could also result in a design
value that is biased low because the extra days could increase the
number of “annual number of days with valid data” enough to affect
which row of Table 1 of Appendix S is used.  It could, for example,
result in the 8th highest ranked daily maximum concentration being
identified as the 98th percentile value (based on Table 1 of Appendix S)
rather than a higher ranked concentration; this would also be
inappropriate because days which were not monitored intensively enough
to give a reasonable likelihood of catching the maximum hourly
concentration would in effect be treated as if they had such a
likelihood.  For example, 50 days with only one hourly measurement
during a time of day with lower concentrations would “earn” the
state the right to drop one notch lower in the ranking of days when
identifying the 98th percentile day, inappropriately.  The final version
of Appendix S solves this problem by providing that two procedures be
used to identifying the 98th percentile value, the first based only on
days with 75% data completeness and the second based on all days with at
least one hourly measurement.  The final design value is the higher of
the two values that result from these two procedures.

	Lastly, with regard to situations with multiple monitors operating at
one site, we think that designation of a primary monitor is preferable
to averaging the data from multiple monitors based on administrative
simplicity and transparency for the public, and is unbiased with respect
to compliance outcome provided the state is able to make the designation
only before any data has been collected.

C.	Exceptional Events Information Submission Schedule

	The Exceptional Events Rule at 40 CFR 50.14 contains generic deadlines
for a state to submit to EPA specified information about exceptional
events and associated air pollutant concentration data.  A state must
initially notify EPA that data has been affected by an event by July 1
of the year after the data are collected; this is done by flagging the
data in AQS and providing an initial event description.  The state must
also, after notice and opportunity for public comment, submit a
demonstration to justify any claim within 3 years after the quarter in
which the data were collected.  However, if a regulatory decision based
on the data (for example, a designation action) is anticipated, the
schedule to flag data in AQS and submit complete documentation to EPA
for review is foreshortened, and all information must be submitted to
EPA no later than one year before the decision is to be made.

	These generic deadlines are suitable for the period after initial
designations have been made under a NAAQS, when the decision that may
depend on data exclusion is a redesignation from attainment to
nonattainment or from nonattainment to attainment.  However, these
deadlines present problems with respect to initial designations under a
newly revised NAAQS.  One problem is that some of the deadlines,
especially the deadlines for flagging some relevant data, may have
already passed by the time the revised NAAQS is promulgated.  Until the
level and form of the NAAQS have been promulgated a state does not know
whether the criteria for excluding data (which are tied to the level and
form of the NAAQS) were met on a given day.  The only way a state could
guard against this possibility is to flag all data that could possibly
be eligible for exclusion under a future NAAQS.  This could result in
flagging far more data than will eventually be eligible for exclusion.
EPA believes this is an inefficient use of state and EPA resources, and
is potentially confusing and misleading to the public and regulated
entities.  Another problem is that it may not be feasible for
information on some exceptional events that may affect final
designations to be collected and submitted to EPA at least one year in
advance of the final designation decision.  This could have the
unintended consequence of EPA designating an area nonattainment as a
result of uncontrollable natural or other qualified exceptional events.

	When Section 50.14 was revised in March 2007, EPA was mindful that
designations were needed under the recently revised PM2.5 NAAQS, so
exceptions to the generic deadline were included for PM2.5.  The EPA was
also mindful that similar issues would arise for subsequent new or
revised NAAQS.  The Exceptional Events Rule at section 50.14(c)(2)(v)
indicates “when EPA sets a NAAQS for a new pollutant, or revises the
NAAQS for an existing pollutant, it may revise or set a new schedule for
flagging data for initial designation of areas for those NAAQS.”

	EPA proposed revised exceptional event data flagging and documentation
deadlines in FR 34404 [Federal Register / Vol. 74, No. 134 / Wednesday,
July 15, 2009 / Proposed Rules] and invited comments from the public.
The Agency received no comments related to the revised proposed schedule
for NO2 exceptional event data flagging and documentation deadlines.

	For the specific case of NO2, EPA anticipates that initial designations
under the revised NAAQS may be made by January 22, 2012 based on air
quality data from the years 2008-2010. (See Section VI below for more
detailed discussion of the designation schedule and what data EPA
intends to use.)    If final designations are made by January 22, 2012,
all events to be considered during the designations process must be
flagged and fully documented by states one year prior to designations,
by January 22, 2011.  This date also coincides with the Clean Air Act
deadline for Governors to submit to EPA their recommendations for
designating all areas of their states.

	The final rule text at the end of this notice shows the changes that
will apply if a revised NO2 NAAQS is promulgated by January 22, 2010,
and designations are made two years after promulgation of a NO2 NAAQS
revision.

	Table 1 below summarizes the data flagging and documentation deadlines
corresponding to the two year designation schedule discussed in this
section.  If the promulgation date for a revised NO2 NAAQS occurs on a
different date than January 22, 2010, EPA will revise the final NO2
exceptional event flagging and documentation submission deadlines
accordingly to provide states with reasonably adequate opportunity to
review, identify, and document exceptional events that may affect an
area designation under a revised NAAQS.

Table 1.  Schedule for Exceptional Event Flagging and Documentation
Submission for Data to be Used in Designations Decisions for New or
Revised NAAQS

NAAQS Pollutant/

Standard/(Level)/

Promulgation Date	Air Quality Data Collected for Calendar Year	Event
Flagging & Initial Description Deadline	Detailed Documentation
Submission Deadline

NO2/1-Hour Standard(100 PPB)	2008	July 1, 2010a	January 22, 2011

	2009	July 1, 2010 	January 22, 2011

	2010	 April 1, 2011a	July 1, 2011a

aIndicates change from general schedule in 40 CFR 50.14.

Note:  EPA notes that the table of revised deadlines only applies to
data EPA will use to establish the final initial designations for new or
revised NAAQS.  The general schedule applies for all other purposes,
most notably, for data used by EPA for redesignations to attainment.

V.	Designation of Areas

A.  	Proposed process

	The CAA requires EPA and the states to take steps to ensure that the
new or revised NAAQS are met following promulgation.  The first step is
to identify areas of the country that do not meet the new or revised
NAAQS.  Section 107(d)(1) provides that, “By such date as the
Administrator may reasonably require, but not later than 1 year after
promulgation of a new or revised NAAQS for any pollutant under section
109, the Governor of each state shall * * * submit to the Administrator
a list of all areas (or portions thereof) in the state” that should be
designated as nonattainment, attainment, or unclassifiable for the new
NAAQS.  Section 107(d)(1)(B)(i) further provides,  “Upon promulgation
or revision of a NAAQS, the Administrator shall promulgate the
designations of all areas (or portions thereof) * * * as expeditiously
as practicable, but in no case later than 2 years from the date of
promulgation.”

No later than 120 days prior to promulgating designations, EPA is
required to notify states of any intended modifications to their
designations as EPA may deem necessary.  States then have an opportunity
to comment on EPA's tentative decision. Whether or not a state provides
a recommendation, the EPA must promulgate the designation that it deems
appropriate.

Accordingly, Governors must submit their initial NO2 designation
recommendations to EPA no later than January 2011.  If the Administrator
intends to modify any state’s recommendation, the EPA will notify the
Governor no later than 120 days prior to designations in January 2012.
States that believe the Administrator’s modification is inappropriate
will have an opportunity to demonstrate why they believe their
recommendation is more appropriate before designations are finalized.

B.	Public comments

	Several industry commenters requested that EPA slow the timeline for
implementing a near-roadway monitoring network and designating roadway
areas because they believe EPA lacks significant information about the
implementation and performance of a national, near-roadway monitoring
network.  Two commenters also requested that if a near-roadway
monitoring network is deployed, that 1-hour NO2 standards be made more
lenient until the next review period so that more information will be
available about near-roadway NO2 concentrations before a stringent
standard is selected.

	A response to commenters’ requests that EPA slow the monitoring
implementation schedule and the request that EPA make the 1-hour NO2
standard more lenient until the next review period are addressed in
sections III.B.5 and II.F.4.D, respectively.

	Section 110(d)(1)(B) requires the EPA to designate areas no later than
2 years following promulgation of a new or revised NAAQS (i.e., by
January 2012).  While the CAA provides the Agency an additional third
year from promulgation of a NAAQS to complete designations in the event
that there is insufficient information to make NAAQS compliance
determinations, we anticipate that delaying designations for an
additional year would not result in significant new data to inform the
initial designations.  A near-roadway monitoring network is not expected
to be fully deployed until January 2013 therefore, EPA must proceed with
initial designations using air quality data from the existing NO2
monitoring network.  Because none of the current NO2 monitors are sited
to measure near-roadway ambient air, we expect that most areas in the
country with current NO2 monitors will not violate the new NO2 NAAQS.
In the event that a current NO2 monitor indicates a violation of the
revised standards, EPA intends to designate such areas
“nonattainment” no later than 2 years following promulgation of the
revised standards.  We intend to designate the rest of the country as
“unclassifiable” for the revised NO2 NAAQS until sufficient air
quality data is collected from a near-roadway monitoring network.  Once
the near-roadway network is fully deployed and 3 years of air quality
data are available, the EPA has authority under the CAA to redesignate
areas as appropriate from “unclassifiable” to “attainment” or
“nonattainment.”  We anticipate that sufficient data to conduct
designations would be available after 2015.

	A number of commenters, largely from industry groups, focused on the
concern that a near-roadway monitoring network would lead to regional
nonattainment on the basis of high NO2 concentrations found near
roadways.  These commenters requested that any future nonattainment
areas be limited to the area directly surrounding roadways found to have
above-standard NO2 concentrations.

The CAA requires that any area that does not meet a NAAQS or that
contributes to a violation in a nearby area that does not meet the NAAQS
be designated “nonattainment.”  States and EPA will need to
determine which sources and activities contribute to a NAAQS violation
in each area.  Depending on the circumstances in each area this may
include sources and activities in areas beyond the area directly
surrounding a major roadway.  EPA intends to issue nonattainment area
boundary guidance after additional information is gathered on the
probable contributors to violating near-roadway NO2 monitors.

C.  	Final designations process

	The EPA intends to promulgate initial NO2 designations by January 2012
(2 years after promulgation of the revised NAAQS).  Along with today’s
action EPA is also promulgating new monitoring rules that focus on
roadways.  As noted in section III, states must site required NO2
near-roadway monitors and have them operational by January 1, 2013.
States will need an additional 3 years thereafter to collect air quality
data in order to determine compliance with the revised NAAQS.  This
means that a full set of air quality data from the new network will not
be available until after 2015.  Since we anticipate that data from the
new network will not be available prior to the CAA designation deadlines
discussed above, the EPA intends to complete initial NO2 designations by
January 2012 using the 3 most recent years of quality-assured air
quality data from the current monitoring network, which would be for the
years 2008-2010.  The EPA will designate as “nonattainment” any
areas with NO2 monitors recording violations of the revised NO2 NAAQS.
We intend to designate all other areas of the country as
“unclassifiable” to indicate that there is insufficient data to
determine whether or not they are attaining the revised NO2 NAAQS.

	Once the NO2 monitors are positioned in locations meeting the
near-roadway siting requirements and monitoring data become available,
the Agency has authority under section 107(d)(3) of the CAA to
redesignate areas as appropriate from “unclassifiable” to
“attainment” or “nonattainment.”  The EPA intends to issue
guidance on the factors that states should consider when determining
nonattainment boundaries after additional information is gathered on the
probable contributors to violating near-roadway NO2 monitors.

VI.	Clean Air Act Implementation Requirements

This section of the preamble discusses the Clean Air Act (CAA)
requirements that states and emissions sources must address when
implementing new or revised NO2 NAAQS based on the structure outlined in
the CAA and existing rules.   EPA may provide additional guidance in the
future, as necessary, to assist states and emissions sources to comply
with the CAA requirements for implementing new or revised NO2 NAAQS.

The CAA assigns important roles to EPA, states, and, in specified
circumstances, Tribal governments to achieve the NAAQS.  States have the
primary responsibility for developing and implementing State
Implementation Plans (SIPs) that contain state measures necessary to
achieve the air quality standards in each area.  EPA provides assistance
to states by providing technical tools, assistance, and guidance,
including information on the potential control measures that may help
areas meet the standards.

States are primarily responsible for ensuring attainment and maintenance
of ambient air quality standards once they have been established by EPA.
 Under section 110 of the CAA, 42 U.S.C. § 7410, and related
provisions, states are required to submit, for EPA approval, SIPs that
provide for the attainment and maintenance of such standards through
control programs directed at sources of NO2 emissions.  If a state fails
to adopt and implement the required SIPs by the time periods provided in
the CAA, the EPA has responsibility under the CAA to adopt a Federal
Implementation Plan (FIP) to assure that areas attain the NAAQS in an
expeditious manner.

The states, in conjunction with EPA, also administer the prevention of
significant deterioration (PSD) program for NO2 and nonattainment new
source review (NSR).  See sections 160-169 of the CAA.   In addition,
Federal programs provide for nationwide reductions in emissions of NO2
and other air pollutants under Title II of the Act, 42 U.S.C.
§§7521–7574, which involves controls for automobiles, trucks, buses,
motorcycles, nonroad engines, and aircraft emissions; the new source
performance standards (NSPS) for stationary sources under section 111 of
the CAA, 42 § U.S.C. 7411.

	CAA Section 301(d) authorizes EPA to treat eligible Indian tribes in
the same manner as states (TAS) under the CAA and requires EPA to
promulgate regulations specifying the provisions of the statute for
which such treatment is appropriate.  EPA has promulgated these
regulations – known as the Tribal Authority Rule or TAR – at 40
C.F.R. Part 49.  See 63 Fed. Reg. 7254 (February 12, 1998).  The TAR
establishes the process for Indian tribes to seek TAS eligibility and
sets forth the CAA functions for which TAS will be available.  Under the
TAR, eligible tribes may seek approval for all CAA and regulatory
purposes other than a small number of functions enumerated at section
49.4.  Implementation plans under section 110 are included within the
scope of CAA functions for which eligible tribes may obtain approval.
Section 110(o) also specifically describes tribal roles in submitting
implementation plans.  Eligible Indian tribes may thus submit
implementation plans covering their reservations and other areas under
their jurisdiction.

	Under the CAA and TAR, tribes are not, however, required to apply for
TAS or implement any CAA program.  In promulgating the TAR EPA
explicitly determined that it was not appropriate to treat tribes
similarly to states for purposes of, among other things, specific plan
submittal and implementation deadlines for NAAQS-related requirements.
40 C.F.R. § 49.4(a).  In addition, where tribes do seek approval of CAA
programs, including section 110 implementation plans, the TAR provides
flexibility and allows them to submit partial program elements, so long
as such elements are reasonably severable – i.e., “not integrally
related to program elements that are not included in the plan submittal,
and are consistent with applicable statutory and regulatory
requirements.”  40 C.F.R. §49.7.

	To date, very few tribes have sought TAS for purposes of section 110
implementation plans.  However, some tribes may be interested in
pursuing such plans to implement today’s proposed standard.  As noted
above, such tribes may seek approval of partial, reasonably severable
plan elements, or they may seek to implement all relevant components of
an air quality program for purposes of meeting the requirements of the
Act.  In several sections of this preamble, EPA describes the various
roles and requirements states will address in implementing today’s
proposed standard.  Such references to states are generally intended to
include eligible Indian tribes to the extent consistent with the
flexibility provided to tribes under the TAR.  Where tribes do not seek
TAS for section 110 implementation plans, EPA will promulgate Federal
implementation plans as “necessary or appropriate to protect air
quality.”  40 C. F. R. §49.11(a).  EPA also notes that some tribes
operate air quality monitoring networks in their areas.  For such
monitors to be used to measure attainment with this primary NAAQS for
NO2, the criteria and procedures identified in this rule would apply.

A.	Classifications

1.	Proposal

Section 172(a)(1)(A) of the CAA authorizes EPA to classify areas
designated as nonattainment for the purpose of applying an attainment
date pursuant to section 172(a)(2), or for other reasons.  In
determining the appropriate classification, EPA may consider such
factors as the severity of the nonattainment problem and the
availability and feasibility of pollution control measures (see section
172(a)(1)(A) of the CAA).  The EPA may classify NO2 nonattainment areas,
but is not required to do so.  The primary reason to establish
classifications is to set different deadlines for each class of
nonattainment area to complete the planning process and to provide for
different attainment dates based upon the severity of the nonattainment
problem for the affected area. However, the CAA separately establishes
specific planning and attainment deadlines for certain pollutants
including NO2 in sections 191 and 192: 18 months from nonattainment
designation for the submittal of an attainment plan, and as
expeditiously as possible, but no later than 5 years from nonattainment
designation for areas to attain the standard.  In the proposal, EPA
stated its belief that classifications are unnecessary in light of these
relatively short deadlines.

2.	Public comments

One commenter stated that they disagree with EPA’s decision not to
impose non-attainment classifications on areas with measured near-road
NO2 concentrations in excess of the new NO2 standard, and urged EPA to
provide a graduated non-attainment classification system for the new
standard.  According to the commenter, “a classification system
defining higher levels of non-attainment with increasingly stringent
requirements at those levels is one that allows for finer calibration of
air quality regulatory response defined at the federal level.”

As stated in the proposed rule, Section 192(a), of part D, of the CAA
specifically provides an attainment date for areas designated as
nonattainment for the NO2 NAAQS.  Therefore, EPA has legal authority to
classify NO2 nonattainment areas, but the 5-year attainment date
addressed under section 192(a) cannot be extended pursuant to section
172(a)(2)(D).  Based on this limitation, EPA proposed not to establish
classifications within the 5- year interval for attaining any new or
revised NO2 NAAQS.  It is also EPA’s belief that given the short
deadlines that States have to develop and submit SIP’s and for areas
to achieve emissions reductions in order to attain the standard within
the 5 year attainment period, a graduated classifications system would
not be appropriate.  Therefore, EPA is using it’s discretion under the
CAA not to establish classifications.

3.	Final

	EPA is not making any changes to the discussion on classifications in
the proposed rule. Therefore, there will be no classifications for the
revised NO2 NAAQS.

B. 	Attainment Dates

	The maximum deadline by which an area is required to attain the NO2
NAAQS is determined from the effective date of the nonattainment
designation for the affected area.  For areas designated nonattainment
for the revised NO2 NAAQS, SIPs must provide for attainment of the NAAQS
as expeditiously as practicable, but no later than 5 years from the date
of the nonattainment designation for the area (see section 192(a) of the
CAA).  The EPA will determine whether an area has demonstrated
attainment of the NO2 NAAQS by evaluating air quality monitoring data
consistent with the form of the NAAQS for NO2 if revised, which will be
codified at 40 CFR part 50, Appendix F.

1.	Attaining the NAAQS

a.	Proposal

In order for an area to be redesignated as attainment, the state must
comply with the five requirements as provided under section 107(d)(3)(E)
of the CAA.  This section requires that:

- 	EPA must have determined that the area has met the NO2 NAAQS;

- 	EPA has fully approved the state’s implementation plan;

- 	the improvement in air quality in the affected area is due to
permanent and enforceable reductions in emissions;

- 	EPA has fully approved a maintenance plan for the area; and

- 	the state(s) containing the area have met all applicable requirements
under section 110 and part D.

b.	Final

	EPA did not receive any comments on this aspect of the proposed rule
and is not making any changes to the discussion on attaining the NAAQS
in the proposed rule.

2.	Consequences of Failing to Attain by the Statutory Attainment Date

a.	Proposal

	Any NO2 nonattainment area that fails to attain by its statutory
attainment date would be subject to the requirements of sections 179(c)
and (d) of the CAA.  EPA is required to make a finding of failure to
attain no later than 6 months after the specified attainment date and
publish a notice in the Federal Register.  The state would be required
to submit an implementation plan revision, no later than one year
following the effective date of the Federal Register notice making the
determination of the area’s failure to attain, which demonstrates that
the standard will be attained as expeditiously as practicable, but no
later than 5 years from the effective date of EPA’s finding that the
area failed to attain.  In addition, section 179(d)(2) provides that the
SIP revision must include any specific additional measures as may be
reasonably prescribed by EPA, including “all measures that can be
feasibly implemented in the area in light of technological
achievability, costs, and any nonair quality and other air
quality-related health and environmental impacts.”

b.	Final

	EPA did not receive any comments on this aspect of the proposed rule
and is not making any changes to the discussion on consequences of
failing to attain by the statutory attainment date in the proposed rule.

C.	Section 110(a)(2) NAAQS Infrastructure Requirements

1.	Proposal

	Section 110(a)(2) of the CAA requires all states to develop and
maintain a solid air quality management infrastructure, including
enforceable emission limitations, an ambient monitoring program, an
enforcement program, air quality modeling, and adequate personnel,
resources, and legal authority.  Section 110(a)(2)(D) also requires
state plans to prohibit emissions from within the state which contribute
significantly to nonattainment or maintenance areas in any other state,
or which interfere with programs under part C to prevent significant
deterioration of air quality or to achieve reasonable progress toward
the national visibility goal for Federal class I areas (national parks
and wilderness areas).

	Under section 110(a)(1) and (2) of the CAA, all states are required to
submit SIPs to EPA which demonstrate that basic program elements have
been addressed within 3 years of the promulgation of any new or revised
NAAQS.  Subsections (A) through (M) of section 110(a)(2) listed below,
set forth the elements that a state’s program must contain in the SIP.
 The list of section 110(a)(2) NAAQS implementation requirements are the
following:

Ambient air quality monitoring/data system:  Section 110(a)(2)(B)
requires SIPs to provide for setting up and operating ambient air
quality monitors, collecting and analyzing data and making these data
available to EPA upon request.

Program for enforcement of control measures:  Section 110(a)(2)(C)
requires SIPs to include a program providing for enforcement of measures
and regulation and permitting of new/modified sources.

Interstate transport:  Section 110(a)(2)(D) requires SIPs to include
provisions prohibiting any source or other type of emissions activity in
the state from contributing significantly to nonattainment in another
state or from interfering with measures required to prevent significant
deterioration of air quality or to protect visibility.

Adequate resources:  Section 110(a)(2)(E) requires states to provide
assurances of adequate funding, personnel and legal authority for
implementation of their SIPs.

Stationary source monitoring system:  Section 110(a)(2)(F) requires
states to establish a system to monitor emissions from stationary
sources and to submit periodic emissions reports to EPA.

Emergency power:  Section 110(a)(2)(G) requires states to include
contingency plans, and adequate authority to implement them, for
emergency episodes in their SIPs.

Provisions for SIP revision due to NAAQS changes or findings of
inadequacies:  Section 110(a)(2)(H) requires states to provide for
revisions of their SIPs in response to changes in the NAAQS,
availability of improved methods for attaining the NAAQS, or in response
to an EPA finding that the SIP is inadequate.

Consultation with local and Federal government officials:  Section
110(a)(2)(J) requires states to meet applicable local and Federal
government consultation requirements when developing SIP and reviewing
preconstruction permits.

Public notification of NAAQS exceedances:  Section 110(a)(2)(J) requires
states to adopt measures to notify the public of instances or areas in
which a NAAQS is exceeded.

PSD and visibility protection:  Section 110(a)(2)(J) also requires
states to adopt emissions limitations, and such other measures, as may
be necessary to prevent significant deterioration of air quality in
attainment areas and protect visibility in Federal Class I areas in
accordance with the requirements of CAA Title I, part C.

Air quality modeling/data:  Section 110(a)(2)(K) requires that SIPs
provide for performing air quality modeling for predicting effects on
air quality of emissions of any NAAQS pollutant and submission of data
to EPA upon request.

Permitting fees:  Section 110(a)(2)(L) requires the SIP to include
requirements for each major stationary source to pay permitting fees to
cover the cost of reviewing, approving, implementing and enforcing a
permit.

Consultation and participation by affected local government:  Section
110(a)(2)(M) requires states to provide for consultation and
participation by local political subdivisions affected by the SIP.

2.	Final

	EPA did not receive any comments on this aspect of the proposed rule
and is not making any changes to the discussion on section 110(a)(2)
NAAQS infrastructure requirements in the proposed rule.

D.  	Attainment Planning Requirements

1.	Nonattainment Area SIPs

a.	Proposal

Any state containing an area designated as nonattainment with respect to
the NO2 NAAQS must develop for submission a SIP meeting the requirements
of part D, Title I, of the CAA, providing for attainment by the
applicable statutory attainment date (see sections 191(a) and 192(a) of
the CAA).  As indicated in section 191(a) all components of the NO2 part
D SIP must be submitted within 18 months of the effective date of an
area’s designation as nonattainment.

Section 172 of the CAA includes general requirements for all designated
nonattainment areas.  Section 172(c)(1) requires that each nonattainment
area plan “provide for the implementation of all reasonably available
control measures (RACM) as expeditiously as practicable (including such
reductions in emissions from existing sources in the area as may be
obtained through the adoption, at a minimum, of  Reasonably Available
Control Technology (RACT)), and shall provide for attainment of the
national primary ambient air quality standards.”  States are required
to implement RACM and RACT in order to attain “as expeditiously as
practicable”.

  tc " " 	Section 172(c) requires states with nonattainment areas to
submit a SIP for these areas which contains an attainment demonstration
that shows that the affected area will attain the standard by the
applicable statutory attainment date.  The state must also show that the
area will attain the standards as expeditiously as practicable, and it
must include an analysis of whether implementation of reasonably
available measures will advance the attainment date for the area.

	Part D SIPs must also provide for reasonable further progress (RFP)
(see section 172(c)(2) of the CAA).  The CAA defines RFP as “such
annual incremental reductions in emissions of the relevant air pollution
as are required by part D, or may reasonably be required by the
Administrator for the purpose of ensuring attainment of the applicable
NAAQS by the applicable attainment date.” (See section 171 of the CAA)
Historically, for some pollutants, RFP has been met by showing annual
incremental emission reductions sufficient to maintain generally linear
progress toward attainment by the applicable attainment date.

All NO2 nonattainment area SIPs must include contingency measures which
must be implemented in the event that an area fails to meet RFP or fails
to attain the standards by its attainment date. (See section 172(c)(9))
These contingency measures must be fully adopted rules or control
measures that take effect without further action by the state or the
Administrator. The EPA interprets this requirement to mean that the
contingency measures must be implemented with only minimal further
action by the state or the affected sources with no additional
rulemaking actions such as public hearings or legislative review.

	Emission inventories are also critical for the efforts of state, local,
and Federal agencies to attain and maintain the NAAQS that EPA has
established for criteria pollutants including NO2.  Section 191(a) in
conjunction with section 172(c) requires that areas designated as
nonattainment for NO2 submit an emission inventory to EPA no later than
18 months after designation as nonattainment.  In the case of NO2,
sections 191(a) and 172(c) also require that states submit periodic
emission inventories for nonattainment areas.  The periodic inventory
must include emissions of NO2 for point, nonpoint, mobile (on-road and
non-road), and area sources.

b.	Public comments

Several commenters indicated that EPA should take steps to ensure that
states actually require mobile source emissions reductions in order to
attain the NO2 NAAQS as opposed to controlling point sources.  Another
commenter went further and stated that states be required to control
on-road emissions as opposed to emissions from stationary sources and in
particular EGUs.  This commenter also indicated that EPA should delay
nonattainment designations until states had a cost effective means of
reducing on-road emissions of NO2.

EPA cannot require states to develop a SIP that only addresses one type
of source, in this case on-road mobile sources.  States may select
appropriate control measures to attain the NAAQS and EPA must approve
them if they otherwise meet all applicable requirements of the Act.  See
CAA § 116.  EPA expects that states will evaluate a range of control
measures that will reduce NO2 emissions within the time allowed to
attain the standard.  This would include the emissions reductions
attributable to Federal controls on on-road and non-road mobile sources,
and controls that they have put in place to reduce NOX emissions in
order to attain the 8-hour ozone NAAQS and/or the PM2.5 NAAQS.  If these
existing controls are not sufficient for an area to reach attainment
with the NO2 NAAQS, EPA would expect the state to implement additional
control measures that would bring the area into attainment by the
deadline.  For a designation based on data from a near roadway monitor
EPA would expect the states to give primary consideration to controlling
emissions from on-road sources; however, it is likely that other types
of sources contribute to the concentrations that are measured at a near
roadway monitor and a state may decide to implement controls on these
other contributing sources.

The Clean Air Act requires that EPA finalize designations within two
years after a NAAQS is revised unless the available air quality data is
insufficient to make designations by that time.  In that case, EPA must
finalize designations within three years after the NAAQS is revised.  As
discussed elsewhere in today’s final rule, EPA believes that it has
sufficient data to make designations within two years and that most
areas will be designated as unclassifiable at that time.  Taking the
additional year provided by the CAA would not allow additional data from
the new near roadway monitors to be factored into the designations
process in any event.  Therefore, it is EPA’s intention to designate
areas within two years as required by the Act.  EPA intends to
redesignate areas once it has sufficient data from the new monitoring
network to designate areas as clearly attaining or not attaining the
standard.

c.	Final

	The EPA is not making any changes to the discussion on nonattainment
area SIPs in the proposed rule.

2.	New Source Review and Prevention of Significant Deterioration
Requirements

a.	Proposal

The Prevention of Significant Deterioration (PSD) and nonattainment New
Source Review (NSR) programs contained in parts C and D of Title I of
the CAA govern preconstruction review of any new or modified major
stationary sources of air pollutants regulated under the CAA as well as
any precursors to the formation of that pollutant when identified for
regulation by the Administrator.  The EPA rules addressing these
programs can be found at 40 CFR 51.165, 51.166, 52.21, 52.24, and part
51, appendix S.  States which have areas designated as nonattainment for
the NO2 NAAQS must submit, as a part of the SIP due 18 months after an
area is designated as nonattainment, provisions requiring permits for
the construction and operation of new or modified stationary sources
anywhere in the nonattainment area. SIPs that address the PSD
requirements related to attainment areas are due no later than 3 years
after the promulgation of a revised NAAQS for NO2.

The NSR program is composed of three different permit programs:

Prevention of Significant Deterioration (PSD)

Nonattainment NSR (NA NSR)

Minor NSR.

The PSD program applies when a major source, that is located in an area
that is designated as attainment or unclassifiable for any criteria
pollutant, is constructed, or undergoes a major modification.  The
nonattainment NSR program applies on a pollutant-specific basis when a
major source constructs or modifies in an area that is designated as
nonattainment for that pollutant.  The minor source NSR program
addresses both major and minor sources which undergo construction or
modification activities that do not qualify as major, and it applies, as
necessary to assure attainment, regardless of the designation of the
area in which a source is located.

	The PSD requirements include but are not limited to the following:

installation of Best Available Control Technology (BACT);

air quality monitoring and modeling analyses to ensure that a
project’s emissions will not cause or contribute to a violation of any
NAAQS or maximum allowable pollutant increase (PSD increment);

notification of Federal Land Manager of nearby Class I areas; and

public comment on permit.

Nonattainment NSR requirements include but are not limited to:

installation of Lowest Achievable Emissions Rate (LAER) control
technology;

offsetting new emissions with creditable emissions reductions;

a certification that all major sources owned and operated in the state
by the same owner are in compliance with all applicable requirements
under the CAA;

an alternative siting analysis demonstrating that the benefits of a
proposed source significantly outweigh the environmental and social
costs imposed as a result of its location, construction, or
modification; and

public comment on the permit.

Minor NSR programs must meet the statutory requirements in section
110(a)(2)(C) of the CAA which requires “…regulation of the
modification and construction of any stationary source …as necessary
to assure that the [NAAQS] are achieved.” Areas which are newly
designated as nonattainment for the NO2 NAAQS as a result of any changes
made to the NAAQS will be required to adopt a nonattainment NSR program
to address major sources of NO2 where the program does not currently
exist for the NO2 NAAQS and may need to amend their minor source program
as well.  Prior to adoption of the SIP revision addressing major source
nonattainment NSR for NO2 nonattainment areas, the requirements of 40
CFR part 51, appendix S may apply.

b.	Public comments

One commenter claimed that EPA’s setting of a more stringent standard,
i.e., short-term NO2 NAAQS, could have important implications for NSR
and PSD and title V permits.

Another commenter indicated that the promulgation of a new 1-hr NO2
short-term standard could create the need for a short-term PSD
increment.  Another commenter stated that a 1-hr NO2 Significant Impact
Level (SIL) should be developed.

The EPA acknowledges that a decision to promulgate a new short-term NO2
NAAQS will clearly have implications for the air permitting process.
The full extent of how a new short-term NO2 NAAAQS will affect the NSR
process will need to be carefully evaluated.  First, major new and
modified sources applying for NSR/PSD permits will initially be required
to demonstrate that their proposed emissions increases of NOX will not
cause or contribute to a violation of either the annual or 1-hour NO2
NAAQS and the annual PSD increment.  In addition, we believe that
section 166 of the CAA authorizes us to consider the need to promulgate
a new 1-hour increment.  Historically, EPA has developed increments for
each applicable averaging period for which a NAAQS has been promulgated.
 However, increments for a particular pollutant do not necessarily need
to match the averaging periods that have been established for NAAQS for
the same pollutant.  Environmental Defense Fund, Inc. v. EPA, 898 F.2d
183, 189-190 (D.C. Cir. 1990)(“… the ‘goals and purposes’ of the
PSD program, set forth in § 160, are not identical to the criteria on
which the ambient standards are based.”)  Thus, we would need to
evaluate the need for a new 1-hour NO2 increment in association with the
goals and purposes of the statutory PSD program requirements.

We also believe that there may be a need to revise the screening tools
currently used under the NSR/PSD program for completing NO2 analyses.
These screening tools include the significant impact levels (SILs), as
mentioned by one commenter, but also include the significant emissions
rate for emissions of NOX and the significant monitoring concentration
(SMC) for NO2.  EPA intends to evaluate the need for possible changes or
additions to each of these important screening tools for NOX/NO2 due to
the addition of a 1-hour NO2 NAAQS.  If changes or additions are deemed
necessary, EPA will propose any such changes for public notice and
comment in a separate action.

c.	Final

	The EPA is not making any changes to the discussion concerning the
requirements for NSR and PSD as stated in the proposed rule.

3.	General Conformity

a.	Proposal

Section 176(c) of the CAA, as amended (42 U.S.C. 7401 et seq.), requires
that all Federal actions conform to an applicable implementation plan
developed pursuant to section 110 and part D of the CAA.  The EPA rules,
developed under the authority of section 176(c) of the CAA, prescribe
the criteria and procedures for demonstrating and assuring conformity of
Federal actions to a SIP.  Each Federal agency must determine that any
actions covered by the general conformity rule conform to the applicable
SIP before the action is taken.  The criteria and procedures for
conformity apply only in nonattainment areas and those areas
redesignated attainment since 1990 (“maintenance areas”) with
respect to the criteria pollutants under the CAA:  carbon monoxide (CO),
lead (Pb), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM2.5
and PM10), and sulfur dioxide (SO2).  The general conformity rules apply
one year following the effective date of designations for any new or
revised NAAQS.

	The general conformity determination examines the impacts of direct and
indirect emissions related to Federal actions.  The general conformity
rule provides several options to satisfy air quality criteria, such as
modeling or offsets, and requires the Federal action to also meet any
applicable SIP requirements and emissions milestones. The general
conformity rule also requires that notices of draft and final general
conformity determinations be provided directly to air quality regulatory
agencies and to the public by publication in a local newspaper.

b.	Final

	EPA did not receive any comments on this aspect of the proposed rule
and is not making any changes to the discussion concerning general
conformity stated in the proposed rule.

4.	Transportation Conformity

a.	Proposal

Transportation conformity is required under CAA section 176(c) (42
U.S.C. 7506(c)) to ensure that transportation plans, transportation
improvement programs (TIPs) and federally supported highway and transit
projects will not cause new air quality violations, worsen existing
violations, or delay timely attainment of the relevant NAAQS or interim
reductions and milestones.  Transportation conformity applies to areas
that are designated nonattainment and maintenance for
transportation-related criteria pollutants:  carbon monoxide (CO), ozone
(O3), nitrogen dioxide (NO2), and particulate matter (PM2.5 and PM10).
Transportation conformity for a revised NO2 NAAQS does not apply until
one year after the effective date of a nonattainment designation. (See
CAA section 176(c)(6) and 40 CFR 93.102(d)).

EPA’s Transportation Conformity Rule (40 CFR 51.390, and Part 93,

Subpart A establishes the criteria and procedures for determining
whether transportation activities conform to the SIP.  The EPA is not
making changes to the Transportation Conformity rule in this rulemaking.
 However, in the future, EPA will review the need to conduct a
rulemaking to establish any new or revised transportation conformity
tests that would apply under a revision to the NO2 NAAQS for
transportation plans, TIPs, and applicable highway and transit projects.

b.	Public comments

Several commenters stated that transportation conformity could stop the
funding of highway and transit projects in NO2 nonattainment areas.
These commenters stated that if an area fails to demonstrate conformity
it enters a conformity lapse and only certain types of projects can be
funded during a lapse.  The commenters further stated that the NO2 NAAQS
will require more areas to determine conformity for the first time.  The
commenters also expressed concern that the NO2 NAAQS proposal did not
contain sufficient information to understand to what extent revisions to
the NAAQS, and the NO2 monitoring requirements, will result in
transportation conformity requirements for individual transportation
projects such as the need for a hot-spot analysis.  The commenters
further stated that hot-spot analyses could result in needless delays
for transportation improvement projects.

With regard to the comment that more areas will have to demonstrate
conformity for the first time due to the revisions to the NO2 NAAQS,
given that today’s final rule is requiring that near roadway
monitoring be carried out in urban areas with populations greater than
350K, EPA believes that most areas with such populations that would be
designated nonattainment for NO2 are already designated nonattainment or
maintenance for one or more of the other transportation-related criteria
pollutants (ozone, PM2.5, PM10 and carbon monoxide).  As such, these
areas would have experience in making transportation conformity
determinations.  If areas with no conformity experience are designated
nonattainment for the NO2 NAAQS, EPA and US DOT would be available to
assist areas in implementing the transportation conformity requirements.

The commenter expressed concern that transportation conformity could
stop highway and transit funding because areas could experience a
conformity lapse and in such cases only certain types of projects could
be funded.  A conformity lapse occurs when an area misses a deadline for
a required conformity determination.  A new nonattainment area must
demonstrate conformity within one year after the effective date of its
designation.  For any areas designated nonattainment for the revised NO2
NAAQS in early-2012, they would have to determine conformity within one
year of the effective date of that designation which would be in
early-2013.  If that date was missed, a lapse would occur and only
projects exempt from conformity such as safety projects, transportation
control measures in an approved SIP for the area and projects or project
phases that were approved by US DOT before the lapse began can proceed
during the lapse.  EPA’s experience in implementing the 1997 ozone and
PM2.5 NAAQS shows that nearly all areas make their initial conformity
determinations within the one-year grace period.  Areas can also lapse
if they fail to determine conformity by an applicable deadline such as
determining conformity within two years after motor vehicle emissions
budgets are found adequate.  However, areas that miss one of these
conformity deadlines have a one-year grace period before the lapse goes
into effect.  During the grace period, the area can continue to advance
projects from the transportation plan and transportation improvement
program.  EPA’s experience is that areas generally are able to make a
conformity determination before the end of the grace period.

The commenter expressed concern that the NO2 NAAQS proposal did not
contain sufficient detail concerning possible project-level requirements
for transportation projects and that any requirements for hot-spot
analyses could needlessly delay transportation projects.  As EPA
indicated in the NPRM, EPA is considering whether to revise the
transportation conformity rule to establish requirements that would
apply to transportation plans, transportation improvement programs
and/or transportation projects in NO2 nonattainment and maintenance
areas.  If EPA concludes that the conformity rule must be revised in
light of the final NO2 NAAQS, we will conduct notice and comment
rulemaking to accomplish the revisions.  At that time interested parties
will have the opportunity to comment on any transportation conformity
NPRM.  This is the same course of action that EPA has taken with respect
to revising the transportation conformity rule for the ozone and PM2.5
NAAQS.

With regard to the commenter’s assertion that a requirement for
hot-spot analyses for individual projects would needlessly delay
transportation projects, EPA disagrees.  First, CAA section 176(c)(1)(B)
requires that transportation projects not cause new violations or make
existing violations worse, or delay timely attainment or cause an
interim milestone to be missed.  EPA would only impose a hot-spot
requirement for projects in NO2 nonattainment and maintenance areas if
they are necessary to comply with CAA conformity requirements and
therefore are needed to protect public health by reducing exposures to
unhealthy levels of NO2 that could be created by the implementation of a
proposed highway or transit project. The public would be exposed to
unhealthy levels of NO2 if a highway or transit project caused a new
violation of the NO2 NAAQS, made an existing violation worse, or delayed
timely attainment or delayed achieving an interim emissions milestone.
If any delay in the project did occur, it would not be viewed as
needless as it occurred for the important purpose of protecting the
exposed public’s health. Second, EPA does not agree that requiring a
hot-spot analysis would needlessly delay projects in NO2 nonattainment
areas.  Such hot-spot analyses, if they are eventually required,
generally would be done as part of the NEPA process, which these
projects are already subject to; therefore, conducting an NO2 hot-spot
analysis would not be introducing a new step to a project’s approval
process, but rather would add one additional analysis which must be
completed as part of an existing project approval process.

c.	Final

EPA is not making any changes to the discussion concerning
transportation conformity as stated in the proposed rule.

VII.	Communication of Public Health Information

Information on the public health implications of ambient concentrations
of criteria pollutants is currently made available primarily through
EPA’s Air Quality Index (AQI) program.  This section describes the
conforming changes that were proposed, major comments received on these
changes, EPA’s responses to these comments and final decisions on the
AQI breakpoints.  Recognizing the importance of revising the AQI in a
timely manner to be consistent with any revisions to the NAAQS, EPA
proposed conforming changes to the AQI in connection with the final
decision on the NO2 NAAQS if revisions to the primary standard were
promulgated.  Conforming changes would include setting the 100 level of
the AQI at the same level as the revised primary NO2 NAAQS and also
setting the other AQI breakpoints at the lower end of the AQI scale
(i.e., AQI values of 50 and 150).  EPA did not propose to change
breakpoints at the higher end of the AQI scale (from 200 to 500), which
would apply to state contingency plans or the Significant Harm Level (40
CFR 51.16), because the information from this review does not inform
decisions about breakpoints at those higher levels.

With regard to an AQI value of 50, the breakpoint between the good and
moderate categories, EPA proposed to set this value to be between 0.040
and 0.053 ppm NO2, 1-hour average.  EPA proposed that the figure towards
the lower end of this range would be appropriate if the standard is set
towards the lower end of the proposed range for the standard (e.g. 80
ppb), while figures towards the higher end of the range would be more
appropriate for standards set at the higher end of the range for the
standard (e.g., 100 ppb).  EPA noted that historically this value is set
at the level of the annual NAAQS, if there is one, or one-half the level
of the short-term NAAQS in the absence of an annual NAAQS, and solicited
comments on this range for an AQI of 50 and the appropriate basis for
selecting an AQI of 50 within this range.

With regard to an AQI value of 150, the breakpoint between the unhealthy
for sensitive groups and unhealthy categories, the range of 0.360 to
0.370 ppm NO2, 1-hour average, represents the midpoint between the
proposed range for the short-term standard and the level of an AQI value
of 200 (0.64 ppm NO2, 1-hour average). Therefore, EPA proposed to set
the AQI value of 150 to be between 0.360 and 0.370 ppm NO2, 1-hour
average.

EPA received comments from several state environmental agencies and
organizations of state and local agencies that generally expressed the
view that the AQI was designed to provide the public with information
about regional air quality and therefore it should be based on
community-wide monitors.  These commenters went on to state that using
near-road NO2 monitors for the AQI would present problems because they
would not represent regional NO2 concentrations and it would be
difficult to communicate this type of information to the public using
the AQI.  Some expressed concern that NO2 measured at near-roadway
monitors could be the critical pollutant and could drive the AQI even
though it may not represent air quality across the area.  Other agencies
expressed concern that there is currently no way to forecast ambient NO2
levels near roadways.  One state agency commented that the AQI is
intended to represent air quality where people live work and play.

EPA agrees with commenters that the AQI should represent regional air
quality, and that measurements that apply to a limited area should not
be used to characterize air quality across the region.  Community-wide
NO2 monitors should be used to characterize air quality across the
region.  However, the AQI reporting requirements encourage, but do not
require, the reporting of index values of sub-areas of an MSA.  We agree
with the commenter that stated the view that the AQI is intended to
represent air quality where people live work and play.  To the extent
that near-roadway monitoring occurs in areas where people live, work or
play, EPA encourages reporting of the AQI for that specific sub-area of
the MSA (64 FR 42548, August 4, 1999).  We also agree that it may be
difficult to communicate this type of information and we plan to work
with state and local air agencies to figure out the best way to present
this information to the public using the AQI.  Air quality forecasting
is recommended but not required (64 FR 42548, August 4, 1999).  EPA will
work with state agencies that want to develop a forecasting program.

With regard to the proposed breakpoints, EPA received few comments.  The
National Association of Clean Air Agencies commented that it would be
confusing to the public to have an AQI value of 50 set below the level
of the annual NO2 standard.  No other comments were received on the
basis for setting this value.  We agree with this comment, and therefore
have decided that it is appropriate to leave the AQI value of 50, the
breakpoint between the good and moderate ranges, set at the numerical
level of the annual standard, 53 ppb NO2, 1-hour average.  The AQI value
of 100, the breakpoint between the moderate and unhealthy for sensitive
groups category, is set at 100 ppb, 1-hour average, the level of the
primary NO2 NAAQS.  EPA is setting an AQI value of 150, the breakpoint
between the unhealthy for sensitive groups and unhealthy categories, at
0.360 ppm NO2, 1-hour average.

VIII.	Statutory and Executive Order Reviews

A.	Executive Order 12866: Regulatory Planning and Review

Under section 3(f)(1) of Executive Order 12866 (58 FR 51735, October 4,
1993), this action is an “economically significant regulatory
action” because it is likely to have an annual effect on the economy
of $100 million or more.  Accordingly, EPA submitted this action to the
Office of Management and Budget (OMB) for review under EO 12866 and any
changes made in response to OMB recommendations have been documented in
the docket for this action.  In addition, EPA prepared a Regulatory
Impact Analysis (RIA) of the potential costs and benefits associated
with this action. However, the CAA and judicial decisions make clear
that the economic and technical feasibility of attaining ambient
standards are not to be considered in setting or revising NAAQS,
although such factors may be considered in the development of State
plans to implement the standards.  Accordingly, although an RIA has been
prepared, the results of the RIA have not been considered in developing
this final rule.

B.	Paperwork Reduction Act

The information collection requirements in this final rule have been
submitted for approval to the Office of Management and Budget (OMB)
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.  The
Information Collection Request (ICR) document prepared by EPA for these
revisions to part 58 has been assigned EPA ICR number 2358.02.

The information collected under 40 CFR part 53 (e.g., test results,
monitoring records, instruction manual, and other associated
information) is needed to determine whether a candidate method intended
for use in determining attainment of the National Ambient Air Quality
Standards (NAAQS) in 40 CFR part 50 will meet the design, performance,
and/or comparability requirements for designation as a Federal reference
method (FRM) or Federal equivalent method (FEM).  We do not expect the
number of FRM or FEM determinations to increase over the number that is
currently used to estimate burden associated with NO2 FRM/FEM
determinations provided in the current ICR for 40 CFR part 53 (EPA ICR
numbers  2358.01).  As such, no change in the burden estimate for 40 CFR
part 53 has been made as part of this rulemaking.

The information collected and reported under 40 CFR part 58 is needed to
determine compliance with the NAAQS, to characterize air quality and
associated health impacts, to develop emissions control strategies, and
to measure progress for the air pollution program.  The amendments would
revise the technical requirements for NO2 monitoring sites, require the
siting and operation of additional NO2 ambient air monitors, and the
reporting of the collected ambient NO2 monitoring data to EPA’s Air
Quality System (AQS).  The annual average reporting burden for the
collection under 40 CFR part 58 (averaged over the first 3 years of this
ICR) is $3,616,487.  Burden is defined at 5 CFR 1320.3(b).  State,
local, and tribal entities are eligible for State assistance grants
provided by the Federal government under the CAA which can be used for
monitors and related activities.

An agency may not conduct or sponsor, and a person is not required to
respond to, a collection of information unless it displays a currently
valid OMB control number.  The OMB control numbers for EPA's regulations
in 40 CFR are listed in 40 CFR part 9.

C.	Regulatory Flexibility Act

The Regulatory Flexibility Act (RFA) generally requires an agency to
prepare a regulatory flexibility analysis of any rule subject to notice
and comment rulemaking requirements under the Administrative Procedure
Act or any other statute unless the agency certifies that the rule will
not have a significant economic impact on a substantial number of small
entities.  Small entities include small businesses, small organizations,
and small governmental jurisdictions.

For purposes of assessing the impacts of this rule on small entities,
small entity is defined as:  (1) a small business that is a small
industrial entity as defined by the Small Business Administration’s
(SBA) regulations at 13 CFR 121.201;  (2) a small governmental
jurisdiction that is a government of a city, county, town, school
district or special district with a population of less than 50,000; and
(3) a small organization that is any not-for-profit enterprise which is
independently owned and operated and is not dominant in its field.

After considering the economic impacts of this final rule on small
entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities.  This final
rule will not impose any requirements on small entities.  Rather, this
rule establishes national standards for allowable concentrations of NO2
in ambient air as required by section 109 of the CAA.  American Trucking
Ass’ns v. EPA, 175 F. 3d 1027, 1044-45 (D.C. cir. 1999) (NAAQS do not
have significant impacts upon small entities because NAAQS themselves
impose no regulations upon small entities). Similarly, the amendments to
40 CFR part 58 address the requirements for States to collect
information and report compliance with the NAAQS and will not impose any
requirements on small entities.

D.	Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public Law
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.  Unless otherwise prohibited by law,
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 one year.  Before
promulgating an EPA rule for which a written statement is required under
section 202, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and to adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule.  The provisions of section 205
do not apply when they are inconsistent with applicable law.  Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted.  Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan.  The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.

This action is not subject to the requirements of sections 202 and 205
of the UMRA.  EPA has determined that this final rule does not contain a
Federal mandate that may result in expenditures of $100 million or more
for State, local, and tribal governments, in the aggregate, or the
private sector in any one year.  The revisions to the NO2 NAAQS impose
no enforceable duty on any State, local or Tribal governments or the
private sector.  The expected costs associated with the monitoring
requirements are described in EPA’s ICR document, but those costs are
not expected to exceed $100 million in the aggregate for any year.
Furthermore, as indicated previously, in setting a NAAQS EPA cannot
consider the economic or technological feasibility of attaining ambient
air quality standards.  Because the Clean Air Act prohibits EPA from
considering the types of estimates and assessments described in section
202 when setting the NAAQS, the UMRA does not require EPA to prepare a
written statement under section 202 for the revisions to the NO2 NAAQS.

With regard to implementation guidance, the CAA imposes the obligation
for States to submit SIPs to implement the NO2 NAAQS. In this final
rule, EPA is merely providing an interpretation of those requirements.
However, even if this rule did establish an independent obligation for
States to submit SIPs, it is questionable whether an obligation to
submit a SIP revision would constitute a Federal mandate in any case.
The obligation for a State to submit a SIP that arises out of section
110 and section 191 of the CAA is not legally enforceable by a court of
law, and at most is a condition for continued receipt of highway funds.
Therefore, it is possible to view an action requiring such a submittal
as not creating any enforceable duty within the meaning of 2 U.S.C. 658
for purposes of the UMRA. Even if it did, the duty could be viewed as
falling within the exception for a condition of Federal assistance under
2 U.S.C. 658.

EPA has determined that this final rule contains no regulatory
requirements that might significantly or uniquely affect small
governments because it imposes no enforceable duty on any small
governments.  Therefore, this rule is not subject to the requirements of
section 203 of the UMRA.

E.	Executive Order 13132: Federalism

Executive Order 13132, entitled “Federalism” (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
“meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.”
 “Policies that have federalism implications” is defined in the
Executive Order to include regulations that have “substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.”

This final rule does not have federalism implications.  It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132.  The rule does not alter the
relationship between the Federal government and the States regarding the
establishment and implementation of air quality improvement programs as
codified in the CAA.  Under section 109 of the CAA, EPA is mandated to
establish NAAQS; however, CAA section 116 preserves the rights of States
to establish more stringent requirements if deemed necessary by a State.
 Furthermore, this rule does not impact CAA section 107 which
establishes that the States have primary responsibility for
implementation of the NAAQS.  Finally, as noted in section E (above) on
UMRA, this rule does not impose significant costs on State, local, or
tribal governments or the private sector.  Thus, Executive Order 13132
does not apply to this rule.

F.	Executive Order 13175: Consultation and Coordination with Indian
Tribal Governments

Executive Order 13175, entitled “Consultation and Coordination with
Indian Tribal Governments” (65 FR 67249, November 9, 2000), requires
EPA to develop an accountable process to ensure “meaningful and timely
input by tribal officials in the development of regulatory policies that
have tribal implications.”  This final rule does not have tribal
implications, as specified in Executive Order 13175.  It does not have a
substantial direct effect on one or more Indian tribes, on the
relationship between the Federal government and Indian tribes, or on the
distribution of power and responsibilities between the Federal
government and tribes.  The rule does not alter the relationship between
the Federal government and tribes as established in the CAA and the TAR.
 Under section 109 of the CAA, EPA is mandated to establish NAAQS;
however, this rule does not infringe existing tribal authorities to
regulate air quality under their own programs or under programs
submitted to EPA for approval.  Furthermore, this rule does not affect
the flexibility afforded to tribes in seeking to implement CAA programs
consistent with the TAR, nor does it impose any new obligation on tribes
to adopt or implement any NAAQS.  Finally, as noted in section E (above)
on UMRA, this rule does not impose significant costs on tribal
governments.  Thus, Executive Order 13175 does not apply to this rule.

G.	Executive Order 13045: Protection of Children from Environmental
Health & Safety Risks

This action is subject to Executive Order (62 FR 19885, April 23, 1997)
because it is an economically significant regulatory action as defined
by Executive Order 12866, and we believe that the environmental health
risk addressed by this action has a disproportionate effect on children.
 The final rule will establish uniform national ambient air quality
standards for NO2; these standards are designed to protect public health
with an adequate margin of safety, as required by CAA section 109.  The
protection offered by these standards may be especially important for
asthmatics, including asthmatic children, because respiratory effects in
asthmatics are among the most sensitive health endpoints for NO2
exposure.  Because asthmatic children are considered a sensitive
population, we have evaluated the potential health effects of exposure
to NO2 pollution among asthmatic children.  These effects and the size
of the population affected are discussed in chapters 3 and 4 of the ISA;
chapters 3, 4, and 8 of the REA, and sections II.A through II.E of this
preamble.

H.	Executive Order 13211: Actions that Significantly Affect Energy
Supply, Distribution or Use

This rule is not a “significant energy action” as defined in
Executive Order 13211, “Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355
(May 22, 2001)) because it is not likely to have a significant adverse
effect on the supply, distribution, or use of energy.  The purpose of
this rule is to establish revised NAAQS for NO2.  The rule does not
prescribe specific control strategies by which these ambient standards
will be met.  Such strategies will be developed by States on a
case-by-case basis, and EPA cannot predict whether the control options
selected by States will include regulations on energy suppliers,
distributors, or users.  Thus, EPA concludes that this rule is not
likely to have any adverse energy effects.

 I.	National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement Act of
1995 (NTTAA), Public Law 104-113, section 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 final rulemaking involves technical standards with regard to
ambient monitoring of NO2.  The use of this voluntary consensus standard
would be impractical because the analysis method does not provide for
the method detection limits necessary to adequately characterize ambient
NO2 concentrations for the purpose of determining compliance with the
revisions to the NO2 NAAQS.

J.	Executive Order 12898: Federal Actions to Address Environmental
Justice in Minority Populations and Low-Income Populations

Executive Order 12898 (59 FR 7629; Feb. 16, 1994) establishes Federal
executive policy on environmental justice.  Its main provision directs
Federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high and adverse
human health or environmental effects of their programs, policies, and
activities on minority populations and low-income populations in the
United States.

EPA has determined that this final rule will not have disproportionately
high and adverse human health or environmental effects on minority or
low-income populations because it increases the level of environmental
protection for all affected populations without having any
disproportionately high and adverse human health effects on any
population, including any minority or low-income population.  The final
rule will establish uniform national standards for NO2 in ambient air.

K.	Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating the