Federal Register / Vol. 73, No. 6 / Wednesday, January 9, 2008 / Rules and Regulations 1497 

(i) The draw of the Belleair Beach 

Drawbridge, mile 131.8, Clearwater, FL 

shall open on signal, except that from 7 

a.m. to 7 p.m., the bridge shall open on 

the hour and half-hour. 

* * * * * 

Dated: December 10, 2007. 

William D. Lee, 

Captain, U.S. Coast Guard, Acting 

Commander, Seventh Coast Guard. 

[FR Doc. E8–191 Filed 1–8–08; 8:45 am] 

BILLING CODE 4910–15–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 50 

[EPA–HQ–OAR–2001–0017; FRL–8502–3] 

RIN 2060–AO59 

Interpretation of the National Ambient 

Air Quality Standards for PM2.5—

Correcting and Simplifying 

Amendment 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Direct final rule. 

SUMMARY: The EPA recently finalized 

changes to the data handling 

conventions and computations 

necessary for determining when the 

annual and 24-hour national ambient air 

quality standards (NAAQS) for fine 

particles (generally referring to particles 

less than or equal to 2.5 micrometers 

(μm) in diameter, PM2.5) are met. These 

changes were made in support of 

revisions to the NAAQS for particulate 

matter (PM) that were finalized in the 

same rulemaking. After publication, 

EPA discovered an inadvertent omission 

in the rule text explaining the 

procedures for calculating the key 

statistic (98th percentile) involved with 

determining compliance with the 24- 

hour PM2.5 standard in locations where 

extra samples of PM2.5 in ambient air 

were taken above the specified sampling 

frequency. If the error in the regulatory 

text is left unchanged, the resulting 

statistic for calculating compliance with 

the 24-hour PM2.5 standard would be 

biased low at some samplers, leading to 

potentially incorrect determinations that 

an area was attaining the NAAQS. In 

this direct final action, EPA is correcting 

this error. The correction involves the 

replacement of the currently used 

statistical formula and instructions with 

a simpler look-up table approach which 

is easier for readers to understand and 

which retains the intended numerical 

consistency with EPA’s historic 

practice. 

DATES: This rule is effective on April 8, 

2008 without further notice, unless EPA 

receives adverse comment by February 

8, 2008. If EPA receives adverse 

comment, EPA will publish a timely 

withdrawal in the Federal Register 

informing the public that this direct 

final rule will not take effect. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–HQ–

OAR–2001–0017 by one of the following 

methods: 

• www.regulations.gov. Follow the 

on-line instructions for submitting 

comments. 

• E-mail: a-and-r-docket@epa.gov. 

• Fax: (202) 566–9744. 

• Mail: Review of the National 

Ambient Air Quality Standards 

(NAAQS) for Particul0ate Matter (PM), 

Environmental Protection Agency, 

Mailcode: 2822T, 1200 Pennsylvania 

Avenue, NW., Washington, DC 20460. 

Please include a total of two copies. 

• Hand Delivery: EPA Docket Center, 

1301 Constitution Avenue, NW., EPA 

Headquarters Library, Room 3334, EPA 

West Building, Washington, DC 20460. 

Such deliveries are only accepted 

during the Docket’s normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information. 

Instructions: Direct your comments to 

Docket ID No. EPA–HQ–OAR–2001–

0017. The EPA’s policy is that all 

comments received will be included in 

the public docket without change and 

may be made available online at: 

http://www.regulations.gov including 

any personal information provided, 

unless the comment includes 

information claimed to be Confidential 

Business Information (CBI) or other 

information whose disclosure is 

restricted by statute. Do not submit 

information that you consider to be CBI 

or otherwise protected through 

www.regulations.gov or e-mail. The 

www.regulations.gov Web site is an 

‘‘anonymous access’’ system, which 

means EPA will not know your identity 

or contact information unless you 

provide it in the body of your comment. 

If you send an e-mail comment directly 

to EPA without going through 

www.regulations.gov, your e-mail 

address will be automatically captured 

and included as part of the comment 

that is placed in the public docket and 

made available on the internet. If you 

submit an electronic comment, EPA 

recommends that you include your 

name and other contact information in 

the body of your comment and with any 

disk or CD–ROM you submit. If EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, EPA may not be 

able to consider your comment. 

Electronic files should avoid the use of 

special characters, any form of 

encryption, and be free of any defects or 

viruses. For additional information 

about EPA’s public docket, visit the EPA 

Docket Center homepage at http:// 

www.epa.gov/epahome/dockets.htm. 

Docket: All documents in the docket 

are listed in the www.regulations.gov 

index. Although listed in the index, 

some information is not publicly 

available, e.g., CBI or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, will be publicly 

available only in hard copy. Publicly 

available docket materials are available 

either electronically in 

www.regulations.gov or in hard copy at 

the Review of the National Ambient Air 

Quality Standards (NAAQS) for 

Particulate Matter (PM) Docket, EPA/ 

DC, EPA West Building, EPA 

Headquarters Library, Room 3334, 

Constitution Ave., NW., Washington, 

DC. The Public Reading Room is open 

from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal 

holidays. The telephone number for the 

Public Reading Room is (202) 566–1744, 

and the telephone number for the Air 

Docket is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: For 

general questions, please contact Mr. 

Lewis Weinstock, U.S. Environmental 

Protection Agency, Office of Air Quality 

Planning and Standards, Air Quality 

Assessment Division, Ambient Air 

Monitoring Group (C304–06), Research 

Triangle Park, North Carolina 27711; 

telephone number: (919) 541–3661; fax 

number: (919) 541–1903; e-mail address: 

weinstock.lewis@epa.gov. For technical 

questions, please contact Mr. Mark 

Schmidt, U.S. Environmental Protection 

Agency, Office of Air Quality Planning 

and Standards, Air Quality Assessment 

Division, Air Quality Analysis Group 

(C304–04), Research Triangle Park, 

North Carolina 27711; telephone 

number: (919) 541–2416; fax number: 

(919) 541–1903; e-mail address: 

schmidt.mark@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Why Is EPA Using a Direct Final Rule? 

II. Does This Action Apply to Me? 

III. Authority 

IV. Judicial Review 

V. Overview of the October 17, 2006 NAAQS 

Rule Changes 

VI. This Action 

VII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

B. Paperwork Reduction Act 


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1498 Federal Register / Vol. 73, No. 6 / Wednesday, January 9, 2008 / Rules and Regulations 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer 

Advancement Act 

J. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

K. Congressional Review Act 

I. Why Is EPA Using a Direct Final 

Rule? 

The EPA is publishing this rule to 

correct and simplify 40 CFR part 50 to 

Appendix N, Interpretation of the 

National Ambient Air Quality Standards 

for PM2.5, without a prior proposed rule 

because we view this as a noncontroversial action and anticipate no 

adverse comment. The change does not 

alter the regulatory requirements on 

affected entities that were promulgated 

in the final rule that was published in 

the Federal Register on October 17, 

2006 (71 FR 61144). The amended rule 

also expresses EPA’s actual intentions, 

as explained in that rulemaking. 

However, in the ‘‘Proposed Rules’’

section of today’s Federal Register, we 

are publishing a separate document that 

will serve as a proposed rule if EPA 

receives significant adverse comments 

on this direct final rule. We will not 

institute a second comment period on 

this action. Any parties interested in 

commenting must do so at this time. For 

further information about commenting 

on this rule, see the ADDRESSES section 

of this document. If EPA receives 

adverse comment, we will publish a 

timely withdrawal in the Federal 

Register informing the public that this 

direct final rule will not take effect. We 

would address all public comments in 

any subsequent final rule based on the 

proposed rule. 

II. Does This Action Apply to Me? 

Categories and entities potentially 

regulated by this action include: 

Category NAICS 

code 1 Examples of regulated entities 

Federal government ....................................................................... 924110 Federal agencies that conduct ambient air monitoring similar to 

that conducted by States under 40 CFR part 58 and that wish 

EPA to use their monitoring data in the same manner as State 

data. 

State/territorial/local/tribal government ........................................... 924110 State, territorial, and local, air quality management programs that 

are responsible for ambient air monitoring under 40 CFR part 

58. The proposal also may affect Tribes that conduct ambient 

air monitoring similar to that conducted by States and that 

wish EPA to use their monitoring data in the same manner as 

State monitoring data. 

1 North American Industry Classification System. 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

regulated by this action. This table lists 

the types of entities that EPA is now 

aware of that could potentially be 

regulated by this action. Other types of 

entities not listed in the table could also 

be regulated. If you have questions 

regarding the applicability of this action 

to a particular entity, consult one of the 

persons listed in the preceding FOR

FURTHER INFORMATION CONTACT section. 

III. Authority 

Two sections of the Clean Air Act 

(CAA) govern the establishment and 

revision of the NAAQS and supporting 

appendices detailing associated Federal 

Reference Methods and NAAQS 

interpretation (data handling) 

procedures. 

Section 108 (42 U.S.C. 7408) directs 

the Administrator to identify and list 

‘‘air pollutants’’ that ‘‘in his judgment, 

may reasonably be anticipated to 

endanger public health and welfare’’

and whose ‘‘presence * * * in the 

ambient air results from numerous or 

diverse mobile or stationary sources’’

and to issue air quality criteria for those 

that are listed. Air quality criteria are 

intended to ‘‘accurately reflect the latest 

scientific knowledge useful in 

indicating the kind and extent of 

identifiable effects on public health or 

welfare which may be expected from the 

presence of [a] pollutant in ambient air 

* * *.’’

Section 109 (42 U.S.C. 7409) directs 

the Administrator to propose and 

promulgate ‘‘primary’’ and ‘‘secondary’’

NAAQS for pollutants listed under 

section 108. Section 109(b)(1) defines a 

primary standard as ‘‘the attainment and 

maintenance of which in the judgment 

of the Administrator, based on such 

criteria and allowing an adequate 

margin of safety, are requisite to protect 

the public health.’’ A secondary 

standard, as defined in section 

109(b)(2), must ‘‘specify a level of air 

quality the attainment and maintenance 

of which, in the judgment of the 

Administrator, based on such criteria, is 

requisite to protect the public welfare 

from any known or anticipated adverse 

effects associated with the presence of 

[the] pollutant in the ambient air.’’

IV. Judicial Review 

Under section 307(b)(1) of the Clean 

Air Act (CAA), judicial review of this 

direct final rule is available only by 

filing a petition for review in the U.S. 

Court of Appeals for the District of 

Columbia Circuit by March 10, 2008. 

Under section 307(d)(7)(B) of the CAA, 

only an objection to this direct final rule 

that was raised with reasonable 

specificity during the period for public 

comment can be raised during judicial 

review. Moreover, under section 

307(b)(2) of the CAA, the requirements 

established by this action may not be 

challenged separately in any civil or 

criminal proceedings brought by EPA to 

enforce these requirements. 

V. Overview of the October 17, 2006 

NAAQS Rule Changes 

On October 17, 2006 (71 FR 61144), 

EPA amended the primary and 

secondary NAAQS for PM to provide 

increased protection of public health 

and welfare by revising the NAAQS for 

PM2.5 and PM10 (generally referring to 

particles less than or equal to 10 

micrometers (μm) in diameter). The rule 

amendments also modified the data 

handling procedures associated with the 

PM10 and PM2.5 NAAQS (Appendices K 

and N of part 50, respectively). 

Appendix K and N describe the 

procedures and equations for 

determining whether a monitoring site 


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2 Guideline on Data Handling Conventions for the 

PM NAAQS, EPA–454/R–99–008, Office of Air 

Quality Planning and Standards, U.S. 

Environmental Protection Agency, Research 

Triangle Park, NC, April 1999. http://www.epa.gov/ 

ttn/oarpg/t1/memoranda/pmfinal.pdf. 

3 40 CFR 58.12(d) describes the required 

operating schedules for manual PM2.5 samplers. 

Although the majority of such samplers must 

operate on a 1-in-3 day operating schedule, a subset 

of samplers is required to operate on a daily 

schedule, and samplers that are collocated with a 

continuous operating PM2.5 monitor may be eligible 

for a reduction to 1-in-6 days sampling if approved 

by the Regional Administrator. 

4Make-up samples are samples taken to replace 

missed or invalidated required scheduled samples. 

Make-up samples can be made by either the 

primary or the collocated instruments. Make-up 

samples are either taken before the next required 

sampling day or exactly one week after the missed 

(or voided) sampling day. The guidance also made 

other suggestions regarding make-up sampling 

practices. 

5The term ‘‘annual 98th percentile value’’ refers 

to a single-year statistic required for the calculation 

of 24-hour PM2.5 design values and should not be 

confused with procedures required for calculation 

of the annual form of the PM2.5 standard that are 

not referenced or modified by this rulemaking. 

6Creditable samples are samples that are given 

credit for data completeness. They include valid 

samples collected on required sampling days and 

valid ‘‘make-up’’ samples taken for missed or 

invalidated samples on required sampling days. 

7The EPA notes that most sites do not take 

supplemental samples; hence, the total number of 

samples is generally equal to the creditable number 

of samples. Also, EPA notes that the collection of 

supplemental samples has a negligible impact on 

the determination of attainment for the annual 

PM2.5 NAAQS since the metric for that standard is 

weighted by quarter. Furthermore, data 

completeness, an integral consideration for 

evaluating attainment of a NAAQS, is based solely 

on creditable samples. 

meets the PM10 and PM2.5 NAAQS, 

respectively. Appendix N of part 50 

(Interpretation of the National Ambient 

Air Quality Standards for PM2.5) was 

revised to incorporate the revised 24- 

hour NAAQS level (i.e., 35 μg/m3), and 

also to make several notable 

enhancements to the previous data 

handling conventions and computations 

(adopted at 62 FR 38755, July 18, 1997). 

These enhancements expanded the 

existing instructions to include relevant 

details for certain special cases 

previously addressed only in a 1999 

EPA guidance document.2 EPA meant to 

make the rule text more explicit in order 

to avoid regulatory ambiguity in these 

special cases. The special cases 

addressed in the 1999 EPA guidance are 

situations in which a monitoring agency 

has performed ‘‘make-up’’ or 

‘‘supplemental’’ sampling of PM2.5. The 

1999 guidance, but not the previous 

version of Appendix N, provided details 

about how these samples could be taken 

into account in the calculation of design 

values used for determining whether 

areas are in compliance with the 24- 

hour PM2.5 NAAQS. 

The monitoring network used for 

determining compliance with the PM2.5

NAAQS is currently based solely on 

filter-based samplers that typically 

operate on a 1-in-3 day sampling 

frequency.3 Such filter-based samplers 

can malfunction resulting in missed or 

invalidated samples. The 1999 guidance 

encouraged monitoring agencies to 

collect make-up samples 4 for such lost 

data, and to use the make-up data in the 

calculation of the design values for the 

monitoring site. Monitoring agencies 

may also collect supplemental samples 

on days falling between required 

sampling days for local purposes, such 

as to better understand the nature and 

causes of a multi-day PM2.5 episode. 

The original (1997) Appendix N did not 

provide explicit procedures addressing 

make-up or supplemental samples. The 

1999 guidance suggested procedures for 

calculating design values in these cases 

which would ensure the appropriate 

treatment of such make-up and 

supplemental samples in the calculation 

of PM2.5 24-hour standard design values. 

As noted in the preamble to the 

October 17, 2006 NAAQS rulemaking, 

EPA intended to incorporate into 

regulation PM2.5 data handling 

procedures that previously had only 

been stated in guidance. 71 FR at 61211. 

In the course of making these intended 

changes, however, an error was made in 

section 4.5 of Appendix N dealing with 

procedures and equations for 

calculating the 24-hour PM2.5 NAAQS 

under certain conditions. As described 

in the following section, this action was 

inadvertent, contrary to EPA’s stated 

intentions, and necessitates correction. 

VI. This Action 

EPA is amending Appendix N in this 

action to correct the Agency’s 

inadvertent error. As a result, the 

procedures in Appendix N will give 

results that will be identical to the 

intended formula (instead of the 

formula that was misstated in the 

October 2006 rulemaking) and also to 

the previous method that had been 

recommended in EPA guidance. In 

addition, this action simplifies the 

procedures for calculating 24-hour 

PM2.5 design values. 

As noted, EPA intended in the 

October 2006 final rule to codify the 

1999 guidance’s procedure for avoiding 

a bias that could be introduced into 

calculations of the 98th percentile 

concentration if supplemental samples 

are unaccounted for in the statistical 

calculations. For example, if 

supplemental ambient samples were 

taken during periods of low PM2.5

concentrations, the annual 5 98th 

percentile value could be biased low 

using the previous (1997) Appendix N 

procedures compared with the statistic 

that would have been generated (using 

that same procedure) if supplemental 

samples were not taken or considered. 

To minimize this bias, the 1999 

guidance and the October 2006 version 

of Appendix N based the annual 98th 

percentile calculation on the creditable 6

number of monitoring samples as 

defined in section 1(c) of the October 

2006 version of Appendix N to 40 CFR 

part 50.7

In the 2006 rule, EPA intended to 

encompass certain relevant details 

previously addressed only in the 1999 

guidance by expanding the existing 

instructions in the text of Appendix N. 

The EPA’s 1999 guidance document 

recommended procedures for 

calculating regular annual PM2.5 98th 

percentile values for two distinct 

situations. Chapter 1 of the guidance 

document addressed a monitoring site 

which had sampled solely on official 

required sample days. One method for 

this situation simply reiterated the 

formula finalized in 1997 accompanied 

by an example. This formula utilized a 

generic sample count (‘‘n’’) which was 

only appropriate when no ‘‘extra’’ (nonscheduled) samples were taken at the 

monitoring site during the year. An 

alternate method for the same situation 

used a table look-up approach, but again 

specified the generic ‘‘n’’ and, hence, 

was also only accurate when there were 

no extra samples taken during the year. 

Chapter 2 of the guidance document 

explained that modifications should be 

made to the stated techniques if there 

were extra samples present for a siteyear. The guidance document 

recommended: (1) Utilizing a sample 

count that accounted for (specifically, 

subtracted) extra samples, and, (2) 

incorporating a term (specifically, 

adding) into the equation accounting for 

the extra sample count. This formula, 

which was misstated in the October 

2006 rulemaking, also produced 

accurate results when no extra samples 

were present since the total ‘‘n’’ was the 

same as ‘‘n’’ minus ‘‘extra samples’’ or 

zero, and also the extra sample term in 

the equation was zero. Chapter 2 in the 

guidance document also noted that the 

table look-up approach in Chapter 1 still 

produced the desired result when extra 

samples were present if only the 

adjusted sample count (‘‘n minus extra 

samples’’) were used in lieu of the total 

sample count (‘‘n’’). This approach also 

produced accurate results whether extra 

samples were present or not. 

In the October 2006 revisions to 

Appendix N, EPA intended to 

incorporate the ‘‘extra sample’’


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1500 Federal Register / Vol. 73, No. 6 / Wednesday, January 9, 2008 / Rules and Regulations 

adjustment logic into the existing 

equation method (71 FR at 61211). The 

sample count reference was modified 

(essentially changing ‘‘n’’ to ‘‘n minus 

extra samples’’) but the ‘‘extra sample’’

term was inadvertently omitted from 

equation 5 of section 4.5 (71 FR at 

61229). That omission would cause 

significant miscalculations to the annual 

98th percentile value when extra 

samples are present if the procedure 

were explicitly followed. The presence 

of extra samples with the misstated 

formula would result in a low bias in 

ascertaining the single-year 98th 

percentile statistic, as well as in 

determining the resulting PM2.5 NAAQS 

comparison metric (24-hour design 

value) based on the three-year average of 

98th percentile statistics. If 

implemented as explicitly stated, the 

misstated formula would improperly 

weaken the stringency of the 24-hour 

PM2.5 NAAQS by showing sites and 

areas to be in attainment of the NAAQS 

when they were actually violating the 

standard. This situation would result in 

the 24-hour standard no longer being 

sufficiently stringent in those areas to 

provide requisite protection to public 

health and welfare, in violation of the 

fundamental requirement for 

establishing NAAQS in section 109(b) of 

the Act. 

For this direct final rule, EPA 

considered two possible approaches to 

correct Appendix N. The first would be 

to correct equation 5 in Appendix N, 

section 4.5 by adding a term and 

footnote indicating that the number of 

extra samples, if taken, would have to 

be added to the current equation result 

(i.e., 1 plus the integer part of the 

product of 0.98 and the creditable 

number of samples) to determine where 

in the ascending data distribution to 

select the 98th percentile value. Such a 

correction would have restored EPA’s 

intention of preserving numerical 

consistency with previous practice in 

calculating the related metrics for 24- 

hour PM2.5 design values, but would 

also have preserved a set of procedures 

that is sensitive to the presence of extra 

samples and is hard to apply without 

providing relatively complex 

instructions. 

The second possible approach would 

be to incorporate a table look-up method 

into Appendix N instead of using an 

equation. The direct final rule uses this 

approach. The EPA believes that the 

incorporation of a table look-up method 

into the Appendix N procedures 

provides a simpler means for calculating 

98th percentile values by employing a 

more intuitive descending sort 

procedure that is unaffected by the 

presence of extra samples in the data 

distribution being examined. For 

example, if the annual number of 

creditable samples at a 1-in-3 day 

monitor is 125, then the appropriate 

98th percentile value is the third 

maximum value in the descending sort 

distribution as noted in the table. If a 1- 

in-6 day monitor has recorded 50 

creditable samples in a year, then the 

98th percentile value is the first 

maximum value in the descending sort 

distribution. 

Accordingly, the rule language of 

section 4.5(a)(1) of 40 CFR part 50, 

Appendix N is amended to replace 

equation 4.5 with a data look-up table 

(table 1) that determines where in the 

descending sorted data distribution the 

98th percentile value is located. EPA is 

also adding rule text to 4.5(a)(1) (labeled 

‘‘Regular procedure for identifying 

annual 98th percentile values’’ in the 

rule) to describe the procedures for 

performing the descending sort 

distribution and for determining the 

appropriate range for selecting the 

correct 98th percentile value based on 

the creditable number of samples. 

To reiterate, this direct final rule both 

eliminates the erroneous terms in the 

equation, and replaces the equationbased procedure for determining the 

98th percentile concentration with a 

table look-up approach that is 

equivalent to the intended equationbased procedure, because the table lookup approach is both correct and much 

easier to understand and execute. In 

fact, several public comments received 

on the proposed Appendix N procedure 

(the proposal underlying the 2006 final 

rule) for determining 98th percentiles 

noted that the treatment of extra 

samples (within that procedure) was 

complex, confusing, and difficult to 

program. Moreover, EPA believes that 

the equation-based procedure itself, 

especially when the extra sample 

adjustment is properly incorporated, is 

more indirect and hence more confusing 

than necessary. EPA’s 1999 guidance 

perhaps contributed to the confusion by 

describing multiple methods which 

could be used for calculating the 

statistical metric. Also, the equationbased procedure promulgated in 1997 

and described in the 1999 guidance 

utilized an ascending sorted data 

distribution which created another 

source of confusion. Descending sorts 

are generally utilized more frequently 

than ascending ones when 

characterizing air quality; for example, 

other criteria pollutant NAAQS focus on 

a fourth maximum concentration or a 

second maximum concentration. The 

alternate 98th percentile calculation 

method outlined in the 1999 guidance—

the table look-up approach—utilizes 

this more intuitive descending sort. EPA 

based the 1999 guidance on a 

descending sort since it was thought to 

be more comprehensible. In addition (as 

outlined in the 1999 guidance), when 

extra samples were present at a site in 

a given year, the promulgated equationbased procedure for the 98th percentile 

calculation required a critical 

adjustment (an added term) to the 

associated equation. (As noted earlier, 

this critical adjustment is what was 

omitted from equation 4.5 of Appendix 

N in the 2006 amendments.) However, 

as correctly stated in the 1999 guidance, 

when extra samples are present and the 

table look-up approach is utilized, no 

such adjustment is necessary. Thus, in 

conclusion and in retrospect, it would 

have been better if EPA had proposed 

and promulgated the table look-up 

approach. Now afforded a second 

opportunity because of the need to 

address the error of the missing term in 

the equation-based procedure, EPA is 

opting to switch to the table look-up 

approach in this rulemaking. 

EPA notes the retention of an 

equation-based procedure (equation 5 of 

section 4.5(a)(2) of 40 CFR part 50, 

Appendix N) to account for sites that 

operate on an approved seasonal 

sampling schedule. An equation-based 

approach is necessary to account for the 

different number of days present in 

‘‘High’’ and ‘‘Low’’ seasons. 

VII. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

This action is not a ‘‘significant 

regulatory action’’ under the terms of 

Executive Order 12866 (58 FR 51735, 

October 4, 1993) and is therefore not 

subject to review under the Executive 

Order. 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

provisions of the Paperwork Reduction 

Act, 44 U.S.C. 3501 et seq. There is no 

information collection requirement 

directly associated with revisions to a 

NAAQS or supporting appendices 

under section 109 of the CAA. 

Burden means the total time, effort, or 

financial resources expended by persons 

to generate, maintain, retain, or disclose 

or provide information to or for a 

Federal agency. This includes the time 

needed to review instructions; develop, 

acquire, install, and utilize technology 

and systems for the purposes of 

collecting, validating, and verifying 

information, processing and 

maintaining information, and disclosing 


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and providing information; adjust the 

existing ways to comply with any 

previously applicable instructions and 

requirements; train personnel to be able 

to respond to a collection of 

information; search data sources; 

complete and review the collection of 

information; and transmit or otherwise 

disclose the information. 

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 today’s rule on small entities, small 

entity is defined as: (1) A small business 

whose parent company has fewer than 

100 or 1,000 employees, or fewer than 

4 billion kilowatt-hr per year of 

electricity usage, depending on the size 

definition for the affected North 

American Industry Classification 

System code; (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 direct 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 direct final rule will not impose 

any requirements on small entities 

because it does not impose any 

additional regulatory requirements. 

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. 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 needed, 

section 205 of the UMRA generally 

requires EPA to identify and consider a 

reasonable number of regulatory 

alternatives and 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 rule contains no Federal 

mandates (under the regulatory 

provisions of Title II of the UMRA) for 

State, local, or tribal governments or the 

private sector. The rule imposes no 

enforceable duty on any State, local or 

tribal governments or the private sector. 

The correcting and simplifying 

change does not create additional 

regulatory requirements on affected 

entities compared to those that were 

promulgated in the final rule that was 

published in the Federal Register on 

October 17, 2006. The rule change only 

corrects and simplifies one error in 

Appendix N of part 50 (Interpretation of 

the National Ambient Air Quality 

Standards for PM2.5). Thus, this final 

rule is not subject to the requirements 

of section 202 and 205 of the UMRA. 

EPA has determined that this direct 

final rule contains no regulatory 

requirements that might significantly or 

uniquely affect small governments. The 

correcting and simplifying change does 

not create additional regulatory 

requirements. 

E. Executive Order 13132: Federalism 

Executive Order 13132 (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 direct 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 change 

being made only corrects and simplifies 

one error in Appendix N of part 50 

(Interpretation of the National Ambient 

Air Quality Standards for PM2.5); thus, 

Executive Order 13132 does not apply 

to this final 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 direct final rule 

does not have tribal implications, as 

specified in Executive Order 13175. The 

change being made only corrects and 

simplifies one error in Appendix N of 

part 50 (Interpretation of the National 

Ambient Air Quality Standards for 

PM2.5). Thus, Executive Order 13175 

does not apply to this rule. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

Executive Order 13045: ‘‘Protection of 

Children from Environmental Health 

Risks and Safety Risks’’ (62 FR 19885, 

April 23,1997) applies to any rule that: 

(1) Is determined to be ‘‘economically 

significant’’ as defined under Executive 

Order 12866, and (2) concerns an 

environmental health or safety risk that 

EPA has reason to believe may have a 

disproportionate effect on children. If 

the regulatory action meets both criteria, 


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1502 Federal Register / Vol. 73, No. 6 / Wednesday, January 9, 2008 / Rules and Regulations 

the Agency must evaluate the 

environmental health or safety effects of 

the planned rule on children, and 

explain why the planned regulation is 

preferable to other potentially effective 

and reasonably feasible alternatives 

considered by the Agency. 

EPA interprets Executive Order 13045 

as applying only to those regulatory 

actions that are based on health or safety 

risks, such that the analysis required 

under section 5–501 of the Order has 

the potential to influence the regulation. 

This direct final rule is not subject to 

Executive Order 13045 because, while it 

is based on the need for monitoring data 

to characterize risk, this direct final rule 

itself does not establish an 

environmental standard intended to 

mitigate health or safety risks. 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This rule is not subject to Executive 

Order 13211, ‘‘Actions Concerning 

Regulations That Significantly Affect 

Energy Supply, Distribution, or Use’’ (66 

FR 28355 (May 22, 2001)) because it is 

not a significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer 

Advancement Act 

As noted in the proposed rule, 

Section 12(d) of the National 

Technology Transfer 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 action does not involve any new 

technical standards for environmental 

monitoring and measurement. Ambient 

air concentrations of PM2.5 are currently 

measured by the Federal reference 

method in 40 CFR part 50, Appendix L 

(Reference Method for the 

Determination of Fine Particulate as 

PM2.5 in the Atmosphere) or by Federal 

Reference Method or Federal Equivalent 

Method that meet the requirements in 

40 CFR part 53. 

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 direct 

final rule will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations 

because it does not affect the level of 

protection provided to human health or 

the environment. The rule merely 

amends the October 17, 2006, final PM 

NAAQS rule (71 FR 61144) by 

correcting and simplifying existing 

PM2.5 data handling conventions and 

computations. 

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 rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. EPA will submit a 

report containing this rule and other 

required information to the U.S. Senate, 

the U.S. House of Representatives, and 

the Comptroller General of the United 

States prior to publication of the rule in 

the Federal Register. 

A Major rule cannot take effect until 

60 days after it is published in the 

Federal Register. This action is not a 

‘‘major rule’’ as defined by 5 U.S.C. 

804(2). This rule will be effective on 

April 8, 2008. 

List of Subjects in 40 CFR Part 50 

Environmental protection, 

Administrative practice and procedure, 

Air pollution control, Intergovernmental 

relations, Reporting and recordkeeping 

requirements. 

Dated: November 29, 2007. 

Stephen L. Johnson, 

Administrator. 

■ For the reasons stated in the preamble, 

title 40, chapter I, part 50 of the Code 

of Federal Regulations is amended as 

follows: 

PART 50—[AMENDED] 

■ 1. The authority citation for part 50 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

■ 2. Appendix N is amended by: 

■ a. Revising section 2.0(c); 

■ b. Revising section 4.2(c); and 

■ c. Revising section 4.5, as follows: 

Appendix N to Part 50—Interpretation 

of the National Ambient Air Quality 

Standards for PM2.5

* * * * * 

2.0 Monitoring Considerations 

* * * * * 

(c) Section 58.12 of this chapter specifies 

the required minimum frequency of sampling 

for PM2.5. Exceptions to the specified 

sampling frequencies, such as a reduced 

frequency during a season of expected low 

concentrations (i.e., ‘‘seasonal sampling’’), 

are subject to the approval of EPA. Annual 

98th percentile values are to be calculated 

according to equation 5 in section 4.5 of this 

appendix when a site operates on a ‘‘seasonal 

sampling’’ schedule. 

* * * * * 

4.2 24-Hour PM2.5 NAAQS 

* * * * * 

(c) The procedures and equations for 

calculating the 24-hour standard design 

values are given in section 4.5 of this 

appendix. 

* * * * * 

4.5 Procedures and Equations for the 24- 

Hour PM2.5 NAAQS 

(a) When the data for a particular site and 

year meet the data completeness 

requirements in section 4.2 of this appendix, 

calculation of the 98th percentile is 

accomplished by the steps provided in this 

subsection. Table 1 of this appendix shall be 

used to identify annual 98th percentile 

values, except that where a site operates on 

an approved seasonal sampling schedule, 

equation 5 of this appendix shall be used 

instead. 

(1) Regular procedure for identifying 

annual 98th percentile values. Identification 

of annual 98th percentile values using the 

regular procedure (table 1) will be based on 

the creditable number of samples (as 

described below), rather than on the actual 

number of samples. Credit will not be 

granted for extra (non-creditable) samples. 

Extra samples, however, are candidates for 

selection as the annual 98th percentile. [The 

creditable number of samples will determine 

how deep to go into the data distribution, but 

all samples (creditable and extra) will be 

considered when making the percentile 

assignment.] The annual creditable number 

of samples is the sum of the four quarterly 

creditable number of samples. 

Procedure: Sort all the daily values from a 

particular site and year by descending value. 

(For example: (x[1], x[2], x[3], * * *, x[n]). 


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Federal Register / Vol. 73, No. 6 / Wednesday, January 9, 2008 / Rules and Regulations 1503 

In this case, x[1] is the largest number and 

x[n] is the smallest value.) The 98th 

percentile is determined from this sorted 

series of daily values which is ordered from 

the highest to the lowest number. Using the 

left column of table 1, determine the 

appropriate range (i.e., row) for the annual 

creditable number of samples for year y (cny). 

The corresponding ‘‘n’’ value in the right 

column identifies the rank of the annual 98th 

percentile value in the descending sorted list 

of daily site values for year y. Thus, P0.98, y

= the nth largest value. 

TABLE 1 

Annual creditable 

number of samples 

for year ‘‘y’’ (cny) 

P0.98, y is the nth 

maximum value of 

the year, where n is 

the listed number 

1–50 .......................... 1 

51–100 ...................... 2 

101–150 .................... 3 

151–200 .................... 4 

201–250 .................... 5 

251–300 .................... 6 

301–350 .................... 7 

351–366 .................... 8 

(2) Formula for computing annual 98th 

percentile values when sampling frequencies 

are seasonal. 

Procedure: Calculate the annual 98th 

percentiles by determining the smallest 

measured concentration, x, that makes W(x) 

greater than 0.98 using equation 5 of this 

appendix: 

Equation 5

W x

d

d d

F x d

d d

F x High

High Low

High

Low

High Low

( ) = Low + ( ) +

+ ( )

Where: dHigh = number of calendar days in the 

‘‘High’’ season; 

dLow = number of calendar days in the ‘‘Low’’

season; 

dHigh + dLow = days in a year; and 

F x number a ( ) = of daily values in season a that are ≤ ×

number of daily values in season a

Such that ‘‘a’’ can be either ‘‘High’’ or ‘‘Low’’; 

‘‘x’’ is the measured concentration; and 

‘‘dHigh/(dHigh + dLow) and dLow /(dHigh + dLow)’’

are constant and are called seasonal 

‘‘weights.’’

(b) The 24-hour standard design value is 

then calculated by averaging the annual 98th 

percentiles using equation 6 of this appendix: 

Equation 6

P0.98

 y

= =

∑P y

0 98

1

3

3

. ,

(c) The 24-hour standard design value (3- 

year average 98th percentile) is rounded 

according to the conventions in section 4.3 

of this appendix before a comparison with 

the standard is made. 

[FR Doc. 07–5954 Filed 1–8 –08; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 180 

[EPA–HQ–OPP–2007–0541; FRL–8343–5] 

Difenoconazole; Pesticide Tolerance 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: This regulation establishes, 

increases, and removes tolerances for 

residues of difenoconazole and also 

establishes tolerances for combined 

residues of difenoconazole and its 

metabolite, CGA-205375, in or on 

various commodities. In addition, this 

regulation revokes tolerances for 

secondary residues in poultry, fat, meat, 

and meat byproducts. Syngenta Crop 

Protection, Inc., requested these 

tolerances under the Federal, Food, 

Drug, and Cosmetic Act (FFDCA). 

DATES: This regulation is effective 

January 9, 2008. Objections and requests 

for hearings must be received on or 

before March 10, 2008, and must be 

filed in accordance with the instructions 

provided in 40 CFR part 178 (see also 

Unit I.C. of the SUPPLEMENTARY

INFORMATION). 

ADDRESSES: EPA has established a 

docket for this action under docket 

identification (ID) number EPA–HQ–

OPP–2007–0541. To access the 

electronic docket, go to http:// 

www.regulations.gov, select ‘‘Advanced 

Search,’’ then ‘‘Docket Search.’’ Insert 

the docket ID number where indicated 

and select the ‘‘Submit’’ button. Follow 

the instructions on the regulations.gov 

website to view the docket index or 

access available documents. All 

documents in the docket are listed in 

the docket index available in 

regulations.gov. Although listed in the 

index, some information is not publicly 

available, e.g., Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available in the electronic docket at 

http://www.regulations.gov, or, if only 

available in hard copy, at the OPP 

Regulatory Public Docket in Rm. S–

4400, One Potomac Yard (South Bldg.), 

2777 S. Crystal Dr., Arlington, VA. The 

Docket Facility is open from 8:30 a.m. 

to 4 p.m., Monday through Friday, 

excluding legal holidays. The Docket 

Facility telephone number is (703) 305–

5805. 

FOR FURTHER INFORMATION CONTACT: 

Janet Whitehurst, Registration Division 

(7505P), Office of Pesticide Programs, 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460–0001; telephone number: 

(703) 305–6129; e-mail address: 

whitehurst.janet@epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. General Information 

A. Does this Action Apply to Me? 

You may be potentially affected by 

this action if you are an agricultural 

producer, food manufacturer, or 

pesticide manufacturer. Potentially 

affected entities may include, but are 


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