Federal Register/Vol. 72, No. 165/Monday, August 27, 2007/Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2006-0583; FRL-8459-2]

Approval and Promulgation of

Implementation Plans; Designation of

Areas for Air Quality Planning,

Purposes; State of California; PM-10;

Affirmation of Determination of

Attainment for the San Joaquin Valley

Nonattainment Area

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Proposed rule.

SUMMARY: In a final rule published in

the Federal Register on October 30,

2006, EPA determined that the San

Joaquin Valley nonattainment area (SJV

or the Valley) in California attained the

National Ambient Air Quality Standards

(NAAQS) for particulate matter with an

aerodynamic diameter less than or equal

to a nominal 10 micrometers (PM-1O).

Since that final determination of

attainment, the State has flagged several

exceedances of the PM-10 standard in

2006 as being caused by exceptional

events, i.e., high winds, and requested

that these data be excluded from

attainment determinations. EPA is

proposing to concur with the State's

request to flag these exceedances and

thus to exclude that data from use in

determining PM-10 attainment for the

SJV. EPA is also proposing to exclude

from use in determining attainment for

the SJV exceedances recorded at a

monitor located at the Santa Rosa

Rancheria, tribal lands within the

boundaries of the SJV, on two bases:

The exceedances occurred while the

monitor was operating in very close

proximity to construction activities and,

as such, the monitor was not properly

sited during that time for purposes of

comparison to the NAAQS; and the

exceedances were caused by an

exceptional. event. EPA is proposing to

concur with the Santa Rosa Rancheria

Tribe's request to flag these exceedances

as due to an exceptional event. As a

result, EPA is proposing to affirm its

determination that the SJV has attained

the PM-10 standard based on EPA's

evaluation of quality-assured data

through December .2006. In addition to

providing the public, with an

opportunity to comment on EPA's

evaluation and proposed concurrence

on flagged exceedances that occurred

through the end of calendar year 2006,

EPA is in this proposed rule addressing

issues raised in petitions for

reconsideration and withdrawal of

EPA's 2006 determination of attainment,

filed by Earthjustice on behalf of the

Sierra Club, Latino Issues Forum and

others.

DATES: Written comments must be

received on or before September 26,'

2007.

ADDRESSES: Submit comments,

identified by docket number EPA-R09-

OAR-2006-0583, by one of the

following methods:

(1) Federal eRulemaking portal:

http://www.regulations.gov. Follow the

on-line instructions.

(2) E-mail: lo.doris@epa.gov.

(3) Mail or deliver: Doris Lo (AIR-2),

U.S. Environmental Protection Agency

Region IX, 75 Hawthorne Street, San

Francisco, CA 94105-3901.

Instructions: All comments will be

included in the public docket without

change and may be made available

online at www.regulations.gov,

including any personal information

provided, unless the comment includes

Confidential Business Information (CBI)

or other information whose disclosure is

restricted by statute. Information that

you consider CBI or otherwise protected

should be clearly identified as such and

should not be submitted through the

www.regulations.gov or e-mail.

www.regulations.gov is an anonymous

access system, and EPA will not know

your identity or contact information

unless you provide it in the body of

your comment. If you send e-mail

directly to EPA, your e-mail address

will be automatically captured and

included as part of the public comment.

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.

Docket: The index to the docket for

this action is available electronically at

www.regulations.gov and in hard copy

at EPA Region IX, 75 Hawthorne Street,

San Francisco, California. While all

documents in the docket are listed in

the index, some information may be

publicly available only at the hard copy

location (e.g., copyrighted material), and

some may not be publicly available in

either location (e.g., CBI). To inspect the

hard'copy materials, please schedule an

appointment during normal business

hours with the contact listed directly

below.

FOR FURTHER INFORMATION CONTACT:

Doris Lo, EPA Region IX, (415) 972-

3959, lo.doris@epa.gov.

SUPPLEMENTARY INFORMATION:

Throughout this document, wherever

"we," "us," or "our" are used, we mean

EPA.

Table of Contents

I. Background

H1. EPA's Proposed Actions

III. Summary of Litigation and

Administrative Proceedings

IV. EPA's Exceptional Events Rule

V. EPA's Evaluation of Flagged Exceedances

A. September 22, 2006 Exceedances at

Corcoran, Bakersfield and Oildale

1. Procedural Requirements

2. Technical Criteria

3. Mitigation Reqxirements

B. October 25, 2006 Exceedances at

Corcoran and Bakersfield

1. Procedural Requirements

2. Technical Criteria

3. Mitigation Requirements

C. December 8, 2006 Exceedances at

Corcoran and Bakersfield

1. Procedural Requirements

2. Technical Criteria

3. Mitigation Requirements

VI. EPA Evaluation of September 14,

September 20 and October 26, 2006

Exceedances Recorded at the Santa Rosa

Rancheria

A. Evaluation Under Principles Established

in 40 CFR Part 58, Appendix E

B. Evaluation Under the Exceptional

-Events Rule

1. Procedural Requirements

2. Technical Criteria

3. Mitigation Requirements

VII. Summary of Exceedances from 2004

through 2006

VIII. Petitions for Reconsideration and

Withdrawal

A. Winds and Wildfires on September 22

and October 25, 2006

B. Notice/Comment on September 22 and

October 25, 2006 Exceedances

C. Wind Conditions in the Valley

D. EPA's Natural Events Policy

1. BACM Implementation

2. District's Natural Events Action Plan

E. Harvest Activities

F. Exceedances at Corcoran and Stockton

in 2004, Bakersfield in 2005 and the

Santa Rosa Rancheria in 2006

IX. Statutory and Executive Order Reviews

I. Background

On October 17, 2006, EPA finalized

its determination that the SJV attained

the NAAQS for PM-IO, and on October

30, 2006, EPA published this

determination in the Federal Register.

71 FR 63642. This determination was

based upon monitored air quality data

for the PM-10 NAAQS 1 during the

years 2003-2005 and all available

quality-assured data through July 31,

2006. For a more detailed discussion of

the related background for the SJV,

please refer to the proposed and final

rules at 71 FR 40952 (July 19, 2006) and

71 FR 63642. Shortly before EPA isstied

the determination of attainment, EPA

learned of preliminary data indicating

that exceedances had occurred on

I EPA's final determination of attainment

addressed both the 24-hour and annual PM-10

standards; however, on October 17, 2006, effective

on December 18, 2006, EPA revoked the annual

PM-10 standard. 71 FR 61144.

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September 22, 2006, at several monitors, proceed with its determination of Since the October 2006 final

and that the State intended to flag 2 attainment at that time. EPA further determination of attainment, EPA has

them as caused by natural events and to indicated that once quality-assured data obtained information regarding the PMwequest that EPA concur with these were available EPA would review those 10 exceedances summarized in Table 1,

flags. EPA stated that because the data data and consider whether the which were recorded at various

were preliminary and because they may . determination of attainment should be monitors within the boundaries of the

qualify as natural events, EPA would withdrawn. SJV:

TABLE 1.-SUMMARY OF EXCEEDANCES EVALUATED FOR TODAY'S PROPOSED RULE

ConcentraDate of exceedance Monitor location (type(s)) tion

(jig/m3)

Septem ber 22, 2006 ................................... C orcoran (FR I , FEM ) ............................................................

215, 261

Bakersfield-G olden (FRM , FEM ) .....................................................

157, 170

O ildale (F R M ) ..................................................................

162

O ctober 25, 2006 ....................................... C orcoran (FE M ) .................................................................

304

Bakersfield-Golden State Highway (FEM) ...............................................

193

D ecem ber 8, 2006 ..................................... : C orcoran (FE M ) ................................................................

162

Bakersfield-Golden State Highway (FEM) ...............................................

213

Septem ber 14, 2006 ................................... Santa Rosa Rancheria (FRM ) ... ; . ................................................

190

Septem ber 20, 2006 ................................... Santa Rosa Rancheria (FRM ) .: . ...............................................

158

O ctober 26, 2006 ....................................... Santa Rosa Rancheria (FR M ) .......................................................

157

* FRM = Federal Reference Method; F.EM = Federal Equivalent Method, 3

On April 24, 2007, the State

submitted to EPA documentation

supporting its claim that the September

22, 2006 exceedances were caused by

high winds and wildfires. This

submittal was supplemented with

additional documentation on July 10,

2007. On May 1, 2007, the State

submitted to EPA documentation

supporting its claim that the October 25,

2006 exceedances were caused by high

winds. On June 12, 2007, the State

submitted to EPA documentation

supporting its claim that the December

8, 2006 exceedances were caused by

high winds. The State believes that all

of these exceedances qualify as natural

events and that the data should thus be

excluded from consideration in the

attainment determination.

On July 9, 2007, EPA met with a

representative of the Santa RosaRancheria EPA to discuss exceedances

recorded on September 14, September

20 and October 26, 2006. The Tribe has

flagged these exceedances as being

caused by an exceptional event related

to construction activities and EPA has

compiled documentation to support that

claim.

II. EPA's Proposed Actions

In this proposed rule, EPA is

proposing to concur with the State's

request to flag exceedances of the PM10 standard within the SJV on

20nce air quality data have been submitted to

EPA, it is possible to "flag" specific values for

various purposes. "Data flagging" refers to the act

of making a notation in a designated field of an electronic data record. The principal purpose of the

data flagging system in the Air Quality System

(AQS) data base is to identify those air quality

September 22, October 25 and December

8, 2006 as being caused by exceptional

events, Le., high winds, and thus to

exclude these data from use in

determining PM-10 attainment for the

SJV. EPA is also proposing to exclude

exceedances recorded at the Santa Rosa

Rancheria, tribal lands within the SJV,

on September 14, September 20 and

October 26, 2006 from use in

determining attainment for the SJV, on

two bases: (1) The exceedances occurred

while the monitor was operating in very

close proximity to construction

activities and, as such, the monitor was

not properly sited during that time for

purposes of comparison to the NAAQS;

and (2) the exceedances were caused by

an exceptional event, i.e., construction

activity in very close proximity to the

monitor. The Tribe has flagged those

exceedances, and EPA is proposing to

concur with those flags.

As a result, EPA is proposing to affirm

its October 2006 attainment

determination based on its evaluation of

quality-assured data from September 14

through December 31, 2006. After

receiving and considering all relevant

public comments on-our proposed rule,

we will publish our final determination

as to whether we will concur with the

State's and Tribe's requests to flag the

exceedances discussed above as affected

by exceptional events and to exclude

them from consideration in our

measurements for which special attention or

handling is warranted. These include, but are not

limited to, those measurements that are influenced

by exceptional events. See 71 FR 12592, 12598

(March 10, 2006).

3 A federal reference method (FRM) is an air

sample collection and analysis method which

attainment determination. We will also

publish our determination as to whether

we will exclude the exceedances at the

Santa Rosa Rancheria as a result of the

monitor siting. EPA is not taking

comment in these proposed actions on

any issues that were the subject of the

2006 attainment determination

rulemaking except to the extent that

they affect EPA's ability to determine

that the SJV continued to attain the PM10 standard through 2006.

In this proposed rule we are also

addressing relevant issues raised in the

petition for reconsideration and petition

to withdraw the determination of

attainment filed by the Latino Issues

Forum and others.

In our 2006 attainment determination

we stated that if, after the September 22,

2006 data were quality-assured, and

after further evaluating the State's

request for exclusion of these data, we

determine that the data do nof qualify

for exclusion and we believe that if

included that they would establish that

the area is in violation of the NAAQS,

EPA would proceed with appropriate

rulemaking action to withdraw its

determination of attainment. 71 FR

63642. Both EPA's natural/exceptional

events policies and its exceptional

events rule anticipate that the Agency

will concur or nonconcur on a state's

request to exclude data by letter rather

than rulemaking.

follows the procedures detailed in the appendices

to 40 CFR part 50. A federal equivalent method

(FEM) is an air sampling collection and analysis

method which does not follow the reference

procedures in 40 CFR part 50, but has been certified

and designated by the EPA as obtaining "equivalent" results.

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Generally we would initiate

rulemaking following an attainment

determination for an area only if we had

preliminarily concluded that a

withdrawal of that determination would

be appropriate. That is not the case here.

However, in this instance both because

EPA had indicated in its final action

that it would reassess the attainment

determination once it had qualityassured data for the September 22, 2006

exceedances and because of the issues

raised by the petitions pending before

the Agency and discussed below, we are

proposing to concur with the State's and

Tribe's requested flags and affirm our

2006 attainment determination via

notice and comment rulemaking.

Because we generally make

determinations of attainment on a

calendar year basis, our proposed rule

addresses quality assured exceedances

from September 14 through December

31, 2006. Moreover the petitions address

exceedances within this timeframe.

11. Summary of Litigation and

Administrative Proceedings

Earthjustice filed three petitions

related to EPA's determination of

attainmeht for the SJV. On.December 27,

2006, Earthjustice, on behalf of Latino

Is~ues Forum, Medical Advocates for

Healthy Air and Sierra Club, filed in the

U.S. Court of Appeals for the 9th Circuit a petition for review of EPA's October

2006 determination under the Clean Air

Act that the SJV has attained the PM10 standard. Latino Issues Forum v.

EPA, No. 06-75831 (9th Cir.). On

December 29, 2006, Earthjustice also

filed with EPA a petition for

reconsideration of our attainment

determination. In the petition,

Earthjustice alleges, among other things,

that EPA improperly ignored September

22, 2006 PM-10 exceedances in the SJV

that were not subject to public notice

and commerit. Finally, on March 21,

2007, Earthjustice'filed a petition for

withdrawal of our attainment

determination. In this petition,

Earthjustice alleges that the attainment

determination must be withdrawn

because, among other things, the

exceedances that occurred in September

and October 2006 do not qualify as

exceptional events. EPA addresses

issues raised in both of these

administrative petitions in this

proposed rule.

IV. EPA's Exceptional Events Rule

On March 22, 2007, EPA issued a

final rule governing the review and

handling of air quality data influenced

by exceptional events. 72 FR 13560. The

rule became effective on May 21, 2007

and implements section 319 of the CAA,

as amended by section 6013 of the Safe

Accountable Flexible EfficientTransportation Equity Act: A Legacy for

Users (SAFE-TEA-LU) of 2005. In the

rule, EPA establishes procedures and

criteria related to the identification,

evaluation, interpretation, and use of air

quality monitoring data related to the

ozone and particulate matter NAAQS

where states petition EPA to exclude

data that are affected by exceptional

events from certain regulatory actions

under the CAA. The rule is codified at

40 CFR 50.1, 50.14, and 51.920. 72 FR

at 13580-13581.

In the preamble to the final rule, EPA

also addresses its applicability to Indian

Tribes. Where, as here, the Santa Rosa

Rancheria Tribe operates an air quality

monitor only in order to gather data for

informational purposes but does not

implement other programs such as

mitigating the effects of exceptional

events, it is EPA's responsibility to

ensure that any exclusion or

discounting of data in Indian country

areas comports with the rule's

procedures and requirements. EPA

intends to work with tribes on the

implementation of the rule. 72 FR at

13563.

In 1986 and 1996 EPA issued

guidance to address the use of data

influenced by exceptional and natural

events: "Guidance on the Identification

and Use of Air Quality Data Affected by

Exceptional Events" (July 1986) and

"Areas Affected by PM-10 Natural

Events," May 30, 1996. CAA Section

319, as amended by SAFE-TEA-LU,

states that these guidance documents

continue to apply until the effective

date of a final regulation promulgated

under section 319(b)(2). See CAA

Section 319(b)(4). SAFE-TEA-LU did

not however address those situations

where EPA had not made a

determination prior to the effective date

of the rule whether an exceptional event

had occurred after a state had flagged

data and submitted a demonstration in

a timely manner to show that such data

reflected NAAQS exceedances that were

caused by an exceptional event. In these

circumstances, EPA believes that in the

interests of equity and administrative

efficiency, a state seeking to exclude

data affected by exceptional events

should, for a limited period of time, be

able to choose to comply with either the

provisions of the rule or those of the

guidance documents for a limited

period of time. This approach would

have some advantages, such as allowing

the state to avoid duplicating its

demonstration process and completing

the decisionmaking process already

underway. EPA believes that it is

reasonable to use this approach until

December 31, 2007 to complete the

transition from the policies to the rule.

However, unless the tate in the

circumstances described above,

specifically requests that EPA evaluate a

natural or exceptional event

demonstration under the guidance

documents, EPA will presume that the

rule applies.

Under 40 CFR 50.14(j), an

"exceptional event," with specified

exceptions not relevant here, is defined

as one "that affects air quality, is not

reasonably controllable or preventable,

is an event caused by human activity

that is unlikely to recur at a particular

location or a natural event, and is

determined by the Administrator in

accordance with 40 CFR 50.14

['treatment of air quality monitoring

data influenced by exceptional events']

to be an exceptional event." A "natural

event" is defined as one "in which

human activity plays little or no direct

causal role." 40 CFR 50.14(k).4

The rule establishes a multi-step

process for identification by states,

tribes and local agencies of data and

submission of the requisite

demonstrations to EPA. 72 FR at 13571.

In short, a state must notify EPA of its

intent to exclude measured exceedances

of a NAAQS as being due to an

exceptional event by "flagging" the data

in EPA's AQS database. 40 CFR

.50.14(c)(2)(i). For PM-IO, the state

should submit the flags, accompanied

by an initial description of the event, by

July 1st of the calendar year following

the year in which the flagged

measurement occurred. 40 CFR

50.14(c)(2)(iii). A state that has flagged

data as being due to an exceptional

event and is requesting its exclusion

must, after notice and opportunity for

public comment, submit a

demonstration that to EPA's satisfaction

shows that the flagged event caused a

specific concentration in excess of the

.NAAQS at the particular location to

justify data exclusion. This

demonstration must be submitted to

EPA within 3 years of the calendar

quarter following the event, but no later

than 12 months prior to an EPA

regulatory decision. A state must submit

the public comments it received along

with its demonstration to EPA. 40 CFR

50.14(c)(3)(i).

4 In the preamble to the final rule, EPA discusses

specific types of natural events, including high

wind events (i.e., those that affect ambient

particulate matter concentrations through the .

raising of dust or through the re-entrainment of

material that has been deposited). See 72 FR at

13565-13566 and 13576-13577. EPA's

interpretation of the rule with respect to high winds

is addressed in section V. below.

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In the preamble to the final rule, EPA

explained that it will generally review

the state's demonstration and provide a

concurrence or nonconcurrence on the

flag in the AQS database within 60 days

of the state's complete submission. EPA

expects that, in most cases, this time

period should be sufficient to review

and provide a concurrence or

nonconcurrence regarding a state's

request to exclude data affected by an

exceptional event. However, for more

complex demonstrations, EPA may

require additional time to make its

decision and will notify the state of the

additional time required. 72 FR at

13571. Upon its concurrence on a flag,

EPA Will exclude the data from use in

determinations of NAAQS exceedances

and violations. 40 CFR 50.14(b),

The requirements for the

demonstration to justify data exclusion

that the state must submit, in this

instance, to EPA are set forth at 40 CFR

50.14(a), (b)(1), and (c)(3)(iii). In order to

be considered for exclusion, the state

must show that the event satisfies the

criteria in section 50.1(j), there is a clear

causal connection between the

exceedances and the claimed

exceptional event, the event is

associated with measured concentration

in excess of normal historical

fluctuations including background and

there would have been no exceedance

"but for" the event. 40 CFR

50.14(c)(iii)(A)-(D).

One of the requirements of section

50.1(j) is that the exceptional event must

be shown to affect air quality, which is

met by establishing that the event is

associated with a measured exceedance

in excess of normal historical

fluctuations, including background. 40

CFR 50.14(c)(iii)(B). In addition,*as

noted above there must be a clear causal

relationship between the measurement

under consideration and the event that

is claimed to have affected the air

quality in the area. 40 CFR

50.14(c)(iii)(C). Air quality impact and

-causal connection may be shown

through a number of methods including

modeling and speciation analysis. EPA

will evaluate whether an event affected

air quality and caused a particular

concentration using the weight of

available evidence and considering the

historical frequency of such measured

concentrations. States must compare

contemporary concentrations with

distribution of historical values and

these may bepresented on a seasonal or

other temporal basis. 40 CFR 50.14(a)(2)

and (c)(3)(iii)(A) and (C); 72 FR at

13569.

Also, air quality data may not be

excluded except where states, tribes, or

local agencies show, through a weight of

evidence approach, that exceedances or

violations of applicable standards

would not have occurred "but for" the

influence of exceptional events. 40 CFR

50.14(c)(3)(iii)(D). 72 FR at 13570-

13571. Finally, states must demonstrate

that they have provided an opportunity

for public comment and must submit

any public comments it received to

EPA. 40 CFR 50.14(c)(3)(i) and (iv).

States, tribes, or local agencies must

also demonstrate that the claimed

exceptional event meets the other

requirements of § 50.1(j)-that the event

is not reasonably preventable or

controllable and that the event is either

caused by human activity that is

unlikely to recur at a particular location

or is a natural event. In this instance,

the claimed events are high winds, i.e.

natural events, and construction, i.e., an

event caused by human activity that is

unlikely to recur at the particular

location.

In order to concur on a state's request

to exclude data, EPA must determine

that the state's submission is complete

and demonstrates to EPA's satisfaction

that the exceptional event caused the

exceedances. Although states must meet

the minimum requirements (e.g. "but

for" test), EPA did not specify a

minimum level of documentation in the

rule because the facts and circumstances

could vary depending on, among others,

meteorology, and geography. Instead,

EPA illustrated through examples the

kind of information that states could

consider in meeting the demonstration

requirements of the rule. In describing

the documentation process and

requirement, EPA also stated that

acceptable documentation would be

determined through consultation with

the EPA regional offices. 72 FR at 13573.

Finally, under 40 CFR 51.930, a state

requesting to exclude air quality data

due to exceptional events must take

appropriate and reasonable actions,

including public notification, public

education and implementation of

measures, to protect public health from

exceedances or violations of the

NAAQS.

V. EPA's Evaluation of Flagged

Exceedances

The State and Tribe have not

specifically requested that EPA evaluate

the September 14 through December 31,

2006 exceedances (which occurred

before the effective date of the

Exceptional Events Rule) under EPA's

natural events policy or exceptional

events policy. Therefore we are

evaluating the State's submittals and the

Santa Rosa Rancheria exceedances

under the Exceptional Events Rule to

determine whether they meet both the

procedural requirements and the

technical criteria for showing that the

exceedances are exceptional. We will

discuss whether the State's submittal

and the exceedances at Santa Rosa

Rancheria meet each of these

requirements and criteria separately. For

each of the exceedances being discussed

in today's proposal, EPA bases. its

evaluation on the procedural

requirements and technical criteria and

mitigatibn requirements of the

Exceptional Events Rule, as discussed

above and summarized below:

Procedural Requirements:.

* Data are flagged ini EPA's AQS

database.

* Public had an opportunity to review

and comment on the state's

documentation.

* The documentation was submitted

to EPA.

* EPA concurs with the state's

demonstration.

Technical Criteria:

* The state must show that the event

satisfies the criteria in 40 CFR 50.1(j). 5

* There is a clear causal connection

between the exceedance and the

claimed exceptional event.

* The event is associated with

measured concentration in excess of

normal historical fluctuations including

background.

* There would have been no

exceedances "but for" the event.

Mitigation Requirements:

* Provide for prompt public

notification of exceedance events.

* Provide for public education on

how to minimize exposure.

* Provide for the implementation of

appropriate measures to protect the

public.

A. September 22, 2006 Exceedances at

Corcoran, Bakersfield, and Oildale

The 24-hour PM-10 NAAQS was

exceeded at three monitoring locations

on September 22, 2006: The Corcoran

monitoring site recorded concentrations

of 215 gg/m 3 and 261 gg/m 3 with a FRM

sampler and a FEM automated

continuous analyzer, 6 respectively; the

5 Section 50.1(j) provides the regulatory definition

of an exceptional event. "Exceptional event" means

an event that affects air quality, is not reasonably

controllable or preventable, is an event caused by

human activity that is unlikely to recur at a

particular location or a natural event, and is

determined by the Administrator in accordance

with 40 CFR 50.14 to be an exceptional event. It

does not include stagnation of air masses or

meteorological inversions, a meteorological event

involving high temperatures or lack of

precipitation, or air pollution relating to source

noncompliance.

6 The FEM monitor currently operated at the

Corcoran site is an automated continuous analyzer

known as a Tapered Element Oscillating

Microbalance (TEOM).

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Bakersfield-Golden State Highway

monitoring site recorded concentrations

of 157 4g/m 3 and 170 gg/m 3 with its

FRM sampler and FEM (TEOM)

analyzers, respectively; and the Oildale

monitoring site recorded a

concentration of 162 gg/m 3 with its

FRM sampler.

The State concludes that three sources

of PM-10 contributed to exceedances of

the 24-hour PM-10 NAAQS on this day:

Wind-entrained dust from sources in the

central and southern SJV, which is

identified as the primary source of PM10; wind-entrained dust from regional

sources from the northern SJV; and

emissions related to several wildfires

which are identified as secondary

sources of PM-IO. 7 Based on the

evidence submitted, EPA agrees with

the State's demonstration that high

wind-entrained dust from sources in the

central and southern SJV caused the

exceedances at the three monitoring

locations on September 22, 2006.

We do not however agree with the

State that emissions from wildfires or

regionally transported dust from the

northern SJV were significant

contributors.

After evaluating the State's

demonstration under the technical

criteria established in the Exceptional

Events Rule, EPA finds that for the

Corcoran, Bakersfield and Oildale areas,

the State does not demonstrate that

emissions from wildfires had a

significant impact on the PM-10

concentrations recorded on September

22, 2006. None of the fires cited in the

documentation was within the

boundaries of the SJV. Further, an

independent review of PM-2.5

speciation data collected at Bakersfield

and Fresno on the days preceding and

after September 22 shows no unusual

concentrations of carbon. See http://

www.epa.gov/cgi-bin/htmSQL/

nxplorer/query spehsql. If the fires had

had a significant effect on PM-IO

concentrations, there would have been

evidence of increased carbon (one of the

chemical constituents of wood smoke)

in the speciation data. The

documentation submitted by the State

includes mostly anecdotal evidence of

the wildfires' impact and satellite

photographs showing smoke over parts

of California. The anecdotal evidence

consists of newspaper reports of

reduced visibility due to smoke and the

odor of wood smoke, as well as

observations from trained weather

observers at Lemoore Naval Air

7

"Natural Event Documentation, Corcoran,

Oildale, and Bakersfield, California, September 22,

2006", April 20, 2007 (NED for September 22, Z006) at 10.

Station.8 EPA finds that the

documentation lacks data linking the

fires to the concentrations given the

distance of the fires and the lack of

corroborating speciation data and

satellite photographs of the smoke, and

newspaper reports do not rise above

general or anecdotal evidence to

establish a clear causal relationship

between the exceedances on September

22, 2006 and the emissions from

wildfires.

Similarly, EPA believes that the

State's documentation that regional

sources of entrained dust impacted*

monitors in the Corcoran and

Bakersfield areas does not show a clear

causal relationship between the

exceedances and regional transport of

PM-10 from the northern SJV. EPA

bases this conclusion on its review of

the documentation which indicates that

while there were high hourly averaged

winds and gusts in the northern central

valley of California, the State did not

present any facts, corroborating

evidence or any convincing argument to

demonstrate how PM-10 from this area

could have reached the southern SJV in

concentrations sufficient to contribute

to an exceedance of the 24-hour PM-10

NAAQS.

Because EPA does not agree with the

State's conclusions with respect to

regional transport of PM-10 from the

northern SJV and with respect to

wildfires, in the following discussion

regarding the September 22, 2006

exceedances we refer only to the State's

conclusion that these exceedances were

caused by wind-entrained dust from

sources in the central and southern SJV.

1. Procedural Requirements

a. Data Are Flagged in EPA's AQS

Database

All of the September 22, 2006

exceedances were flagged in EPA's AQS

database as of July 2007.

b. Public Had an Opportunity To

Review and Comment on the State's

Documentation

In February 2007, the SJV Air

Pollution Control District (SJVAPCD or

District} notified the public in local

newspapers and on its Web site of the

availability of the document entitled

"Natural Event Documentation, High

Winds, Corcoran and Bakersfield,

California, September 22, 2006," SJV

Unified Air Pollution Control District,

February 2007 and requested public

comments by March 5, 2007.

The SJVAPCD subsequently revised

the February 2007 document and

5NED for September 22, 2006 at 11, Table 3, 14

and 37-44.

submitted to the California Air

Resources Board (CARB) "Natural Event

Documentation, Corcoran, Oildale and

Bakersfield, California, September 22,

2006," SJV Unified Aii Pollution

Control District, April 20, 2007 (NED for

September 22, 2006) and posted it on its

Web site.

SJVAPCD thereafter provided

additional information to CARB in "Addendum, Natural Event

Documentation, Corcoran, Oildale and

Bakersfield, California, September 22,

2006," SJV Unified Air Pollution

Control District, May 23, 2007 (NED

Addendum for September 22, 2006) and

posted it on its Web site.

The District indicated that no public

comments were received during the

public process.

c. The Documentation Was Submitted to

EPA

The NED for September 22, 2006 and

the NED Addendum for September 22,

2006 were subsequently submitted by

the State to EPA on April 24, 2007 and

-July 10, 2007, respectively, and are the

documents upon which EPA is basing

its evaluation below.

d. EPA Concurs With the State's

Demonstration

In this proposed rule, EPA-is

proposing to concur with the State's

demonstration in the NED for

September 22, 2006 and the NED

Addendum for September 22, 2006 that

high wind-entrained dust from the

central and southern SJV caused the

exceedances at the three monitoring

locations on September 22, 2006.

2. Technical Criteria

a. Did this event satisfy the criteria in

section 50.1(j) of the Rule?

The State needs to show that the

September 22, 2006 event, windentrained dust from sources in the

central and southern SJV, affected air

quality in the Corcoran and Bakersfield

areas, 9 was not reasonably controllable

or preventable, was a natural event, and

is determined by EPA through the

process established in the Rule to be an

exceptional event. We believe the State

has supported its claims that winddriven dust from sources of PM-10 in

the central and southern SJV was the

cause of the September 22, 2006

exceedances, as discussed in detail

below.

9 The Bakersfield-Golden State Highway and

Oildale monitors are approximately 3.5 miles apart.

For the purposes of this discussion, the analysis for

the Bakersfield-Golden State Highway and Oildale

monitors is the same.

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i- Affected Air Quality

For an event to qualify as an

exceptional event, the state must show

that the event affected air quality. This

criterion can be met by establishing that

the event is associated with a measured

exceedance in excess of normal

historical fluctuations, including

background, and there is a causal

connection between the event and the

exceedance. The demonstration of a

clear causal relationship is necessary to

establish that the event affected air

quality and is also a separate statutory

requirement as discussed above.

In the NED for September 22, 2006

and the NED Addendum for September

22, 2006, the State provides

documentation that the measured

exceedances on September 22, 2006 were in excess of normal historical

fluctuations. See subsection c. below.

The State.also establishes a causal

connection between the high winds

recorded at Lemoore and the high

concentrations recorded at the Corcoran,

Bakersfield, and Oildale monitors. The

State's demonstration of the clear causal

relationship between, the event and the

exceedances on this day is discussed in

greater detail in subsection b. below.

ii. Not Reasonably Controllable or

Preventable

Section 50.1(j) of the Exceptional

Events Rule requires that for an event to

qualify as an exceptional event, whether

natural 6r anthropogenic, a state must

show that the event was not reasonably

preventable or controllable. Here this

requirement is met by demonstrating

that despite reasonable and appropriate

measures in place, the September 22,

2006 wind event caused the

exceedances. During this event there were no other unusual dust-producing

activities occurring in the SJV and

anthropogenic emissions were

approximately constant before, during

and after the event. In addition, the

State shows that reasonable and

appropriate measures were in place,

including Regulation VIII (the District's

general fugitive dust rules) and Rule

4550 which limits fugitive dust

emissions specifically from agricultural

operations through Conservation

Management Practices.' 0 Moreover, EPA

has approved the District's best

available control measure (BACM)

demonstration for all significant sources

of PM-10 in the SJV as meeting CAA

section 189(b)(1)(B). 11

1

0 NED for September 22, 2006 at 32. 1169 FR 30006, 30035 (May 26, 2004); 71 FR 7683

(February 14, 2006).

iii. Wag ia Natural Event

In the preamble to the Exceptional

Events Rule EPA states that ambient

particulate matter concentrations due to

dust being raised by unusually high

winds will be treated as due to

uncontrollable natural events where (1)

the dust originated from

nonanthropogenic sources, or (2) the

dust originated from anthropogenic

sources within the State, that are

determined to have been reasonably

well-controlled at the time that the

event occurred, or from anthropogenic

sources outside the State. 72 FR at

13576. In the preamble EPA also

explains that "[sitates must provide

appropriate doeumentation to

substantiate why the level of wind

speed associated with the event in

question should be considered unusual

for the affected area during the time of

year that the event occurred." Id. at

13566.

On September 22, 2006, the windentrained dust originated from

anthropogenic sources within

California, i.e., from usual dustgenerating activities such as agricultural

and industrial operations.' 2 We discuss

the fugitive dust control measures in

place in the SJV on September 22 above.

With respect to the wind speed, EPA concurs with the State's demonstration

-that the wind speeds in the central SJV were unusually high on September 22,

2006.13 Meteorological data show that

the winds at Lemoore reached speeds of

29 mph with gusts of approximately 40

mph. According to the State, the

Department of Water Resources' extreme

annual wind statistics indicate that the

mean annual peak gust for Lemoore is

42 mph.14 Thus wind gusts observed at

Lemoore were unusually high because

they are close to the typical highest

annual value of 42 mph. The State also

provides documentation that shows that

winds of approximately 18 mph will

entrain and transport dust.1 5 Winds

greater than this speed occurred at

Lemoore and Kettleman Hills, and were

responsible for transporting this

entrained dust. Meteorological data

indicate that the wind direction was from the north and northwest and hence

the entrained dust at that wind speed

was transported towards Corcoran.

Winds at Corcoran were not as iritense

during the peak hours at Lemoore. Table

1

2 NED for September 22, 2006 at 32-33.

13NED for September 22, 2006 at 29; NED

Addendum for September 22, 2006 at section 4. 14 NED for September 22, 2006 at 29.

isNED for September 22, 2006 at 13; David Bush,

T&B Systems Contribution to CRPAQS Initial Data

Analysis of Field Program Measurements, Final

Report Contract 2002-O6PM Technical & Business

Systems, Inc., November 9, 2004 (Bush Report).

3 of the State's submittal indicates the

winds at Corcoran at 10 a.m. were 9

mph with gusts to 12 mph.16 These

wind speeds, though not sufficient to

erode dust, were sufficient to keep the

entrained and transported dust from the

high winds at Lemoore suspended for

the period during which the

exceedances occurred.

iv. Determined by EPA To Be an Exceptional Event

Finally, EPA must determine through

the process established in the

Exceptional Events Rule whether an exceptional event occuired. We believe

that the State has met the procedural

requirements of the rule including

flagging of the data, submission of

demonstration, evidence of the public

opportunity to review and comment on the demonstration and mitigation

requirements al discussed in section

V.A.1. and 3. of this proposed rule. We

further believe that the State has also

met the technical criteria in the

Exceptional Events;Rule as discussed in

section V.A.2. Therefore, we are

proposing to concur with the State's

determination that an exceptional event,

i.e., a high wind event, occurred

resulting in the exceedances on September 22, 2006.17

b. Does the State's documentation show a clear causal connection between the

exceedances and the claimed

exceptional event?

Under 40 CFR 50.14(c)(3)(iii)(B), a

state's demonstration must establish a

clear causal relationship between the

measured exceedance and the claimed

exceptional event. In addressing this

requirement for the September 22, 2006

exceedances, the State identifies a source region for the PM-IO, an area

northwest of Corcoran around the area

of Lemoore. The State provides a

convincing demonstration showing that

the winds in the area of the central SJV

were of sufficient speeds to erode soils

and entrain dust and that the wind

direction moved the PM-10 southeast

towards Corcoran and further to the

Bakersfield area.-

Meteorological measurements in

Lemoore show that this area had the

highest hourly averaged winds in the

SJV that day, peaking at 10 a.m. with a

speed of 29 mph from the NNW and

gusts at the same time reaching 37

16NED Addendum for September 22, 2006 at 11,

Table 3. 17 Generally EPA concurs or nonconcurs by letter

with requests to flag data as caused by exceptional

events. See our explanation in section I. above

regarding why we are proceeding by a rulemaking

here.

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mph.18 Lemoore is approximately 25

miles northwest of Corcoran.

Meteorological measurements were also

obtained from a site at Kettleman Hills,

which showed a peak hourly wind at 11

am of 20 mph from the NNW with gusts

up to 32 mph. 19 Kettleman Hills is

approximately 28 miles west of

Corcoran. The wind speed, direction,

time and distance from monitors

indicate that the high winds at Lemoore

entrained the dust carrying it toward

Corcoran. 20 The State cites a 2002

California.Regional PM-10/PM-2.5 Air

Quality Study (2002 CRPAQS study)

that established a dust-generating wind

speed threshold of 17.8 mph to support

its conclusion that these wind speeds

were sufficient to erode soils and

entrain dust into the atmosphere as well

as to exacerbate the entrainment of dust

from the anthropogenic activities.2 1

At about 9:30 a.m. and 10:30 a.m. the

District received complaints about dust

emissions in Leinoore. 22 This was at the

time of peak winds in Lemoore. The

District followed up on the complaints

but did not issue notices of violation.

The State indicates that there were PM10 generating activities in the area of

Lemoore on the morning of September

22, 2006 but that these activities were typical for the area and subject to the

District's fugitive dust regulations.23

The State shows a clear relationship

between the wind speeds at Lemoore

and Kettleman Hills and increased

concentrations at the Corcoran

monitoring site. The documentation

clearly shows that as hourly average

wind speeds increased at the three

meteorological sites, hourly

concentrations at Corcoran also

increased. The peak hourly

concentrations at Corcoran were at 10

a.m. and 11 a.m. (725 jg/m3 and 695 Jg/

M 3 , respectively).24 These

concentrations coincide with the

highest winds at Lemoore and

Kettleman Hills.

The winds at Corcoran showed the

same pattern of increasing wind speeds

but at a lower intensity. Hourly average

winds at Corcoran peaked at 8 a.m. at

11 mph with a peak average minute gust

of 15 mph. While these wind speeds

were not high enough to erode and

entrain soil, based on the wind speed

threshold referenced above, they were

sufficient to keep the coarse particles

suspended in the atmosphere. The

18 NED for September 22, 2006 at 11, Table 3.

-led"

20 fd.

21Id. at 13; Bush Report. 22 NED for September 22, 2006 at 33, Table 15.

23Id. at 5 and 32-33.

24Id. at 11, Table 3.

winds were also consistently from the

northwest, which demonstrates that the

coarse particles which impacted

Corcoran originated in the areas

northwest of the monitor, e.g. Lemoore

where the winds were unusually high.

Using the threshold wind speed in the

2002 CRPAQS study, the State shows

that most of the PM-10 was generated

upwind of the Corcoran site and then

transported to the Corcoran area.25

Based on available data, wind speeds at

Corcoran were not high enough to

generate dust on their own but were

high enough to sustain the entrainment

of PM-10 from upwind areas.

- The wind-driven dust from sources in

the central and southern SJV, beginning

in Lemoore, also impacted the

Bakersfield area on September 22, 2006.

The State provides the analysis and

supporting information needed to

demonstrate that the winds between the

Corcoran and Bakersfield areas were of

sufficient intensity to transport the

plume of PM-10 from Corcoran to the

Bakersfield and Oildale monitors. The

Bakersfield area monitors began to

record hourly c6ncentrations in excess

of the level of the 24-hour PM-la

NAAQS two hours after the peak

Corcoran hourly PM-10 concentration,

with the Bakersfield hourly PM-10

concentrations peaking five hours after

the Corcoran peak hourly PM-10

concentration. In order to transport a

plume of dust from Corcoran to the

Bakersfield area, approximately 55

miles, wind speeds would have to

average approximately 11 mph in order

for the maximum amount of PM-10 to

impact the Bakersfield area monitors

five hours later.26 The winds at

Alpaugh, which is located between

Corcoran and Bakersfield, averaged 11

mph.27 As Would be expected, the

concentration of PM-10 in the

Bakersfield area was lower than in

Corcoran, but still significant enough to

exceed the NAAQS. The lower PM-10

concentrations at Bakersfield are likely

due to the dispersion of the dust plume

and possibly deposition of a portion of

the dust particles along the path from

the Corcoran area to Bakersfield.

The State's demonstration for

September 22, 2006 includes

information on wind speed and

direction 28 that shows the correlation

between the hourly wind speeds at

meteorological sites in Alpaugh and

Bakersfield-Meadows Airfield and the

25 Id. at 13; Bush Report.

26 NED Addendum for September 22, 2006 at 7. 27 

Id. at 8, Table A-1.

28 NED Addendum for September 22, 2006 at 8,

Table A-1.

hourly PM-10 concentrations recorded

in the Bakersfield area. 29

The State also includes the results of

a basic meteorological model known as

Hybrid Single-Particle Lagrangian

Integrated Trajectory. model

(HYSPLIT).30 It is important to note that

while this modeling is not meant to

quantify the particle concentration

recorded in the Bakersfield area, it does

offer support of the State's

demonstration that the winds on

September 22, 2006 were of the

appropriate intensity and direction to

move a plume of dust from the central

SJV to the Bakersfield area.

c. Did the State demonstrate that the

event is associated with measured

concentration in excess of normal

historical fluctuations including

background?

For EPA to concur with a state's claim

that an exceptional event caused an

exceedance, one of the requirements

that the state must meet is to show that

the event is associated with

concentrations that are beyond the

normal historical fluctuations. See 40

CFR 50.14(c)(3)(iii)(C).

The NED for September 22, 2006 and

NED Addendum for September 22, 2006

include sections that show the

unusualness of the concentrations

recorded on that date. Section 4 of the

Addendum includes Figure A-5 that

compares the peak 24-hour PM-10

concentrations recorded at Corcoran,

Bakersfield and Oildale during the

month of September for the years 2000

through 2006.31

The FRM monitor at the Corcoran site

has mostly operated on a once-in-everythree-days schedule since 2000.32 The

Corcoran FRM has collected 786

samples since 2000 and has recorded

only four exceedances of the 24-hour

PM-10 NAAQS. 33 A further analysis

shows that, with the exception of a

flagged natural event in 2004, 24-hour

29The Oildale monitoring site does not record

hourly PM-10 concentrations but uses a manual

PM-10 sampler that provides only 24-hour average

concentrations. The Bakersfield-Golden State

Highway monitoring site utilizes both a manual

sampler for ai'erage 24-hour PM-10 concentrations

and a continuous PM-la analyzer to provide hourly

concentrations. Since the Bakersfield-Golden State

Highway site and the Oildale site are relatively

close to each other (see footnote 9 above), we

believe it is appropriate to ue the BakersfieldGolden State Highway continuous analyzer to

characterize the temporal distribution of hourly

contentrations at both sites.

30 NED Addendum for September 22, 2006 at 10.

31 NED Addendum for September 22, 2006 at 14. 32 From September 1, 2000 to March 22, 2001 the

Corcoran monitor operated on a once-in-every-sixdays schedule.

33 PM-10 Raw Data Report Corcoran 2000-2006,

EPA AQS Database, July 30, 2007.

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PM-10 concentrations exceeded a level

of 100 gg/m 3 only three times during the

month of September for a seven year

period, i.e, when we look at the 59

samples collected during the September

for the past seven years, a concentration

greater than .100 gg/m 3. occurred only

five percent of the time. 34 Exceedances

of the NAAQS have occurred twice in

September, which is less than four

percent of the days sampled.

Comparisons for the month of

September are more relevant than for

the entire year because September has

the highest concentration of dust but

does not typically have the highest PM10 concentrations, which occur in the

winter season. Dust is typically less

than 50% of the PM-10 during

September. 35 During the winter season

nitrates are the largest contributor,

particularly in the southern part of the

central valley.

For Bakersfield, which utilizes a FRM

operating on a once-in-every-six-days "

schedule, 413 samples were collected

since the year 2000. During this time the

NAAQS was exceeded three times.

Again, when we look at data collected

during the September months from 2000

to 2006, only one day out of 33 days

sampled recorded a level greater than

100 gg/m 3 (128 jig/m 3 on September 18,

2003), three percent of the time. 36

For Oildale, also operating a FRM on

a once-every-six-days schedule, 432

samples were collected from 2000 to

2006. The PM-10 NAAQS was exceeded

once during this seven-year period.

During the September nionths, only one

day out of 35 days sampled recorded a

level greater than 100 g.g/m3 (111 jig/m 3

on September 14, 2006), less than three

percent of the time. 37

d. Did the State demonstrate that there

would have been no exceedance "but

for" the event?

As discussed above, to qualify as an

exceptional event the state must also

demonstrate that there would have been

no exceedance "but for" the event. 40

CFR 50.14 (c)(3)(iii)(D). To meet this

"but for" criterion, states must include

analyses to demonstrate that an

exceedance or violation would not have

occurred but for the event. Such

analyses do not require a precise

34 138 1 ig/m3 on September 9, 2004, a 102 gig/m3

on September 24, 2004 and a 112 pg/m 3 on

September 23, 2006; See Id. 3

5 "What are the Sources of Particulate Matter",

Presentation by Karen L. Magliano, California Air

Resources Board, May 17, 2006 (Magliano

Presentation). 3

6 PM-10 Raw Data Report Bakersfield Golden

2000-2006, EPA AQS Database, July 30, 2007. 37 PM-10 Raw Data Report Oildale 2000-2006,

EPA AQS Database, July 26, 2007.

estimate of the'estimated air quality

impact from the event. 72 FR at 13570.

To meet this "but for" criterion, the

State first shows that there were no

unusual activities occurring in the

affected areas in the Valley on

September 22, 2006 that could have

resulted in the exceedances.

Specifically, based on information from

District field staff and discussions with

representatives of agricultural and

industrial operations in the Valley,

anthropogenic emissions were

approximately constant in the Valley

immediately before, during and after the

event. The State indicates that there

were PM-10 generating activities, such

as agricultural and construction

operations, in the area of Lemoore on

the morning of September 22, 2006.

These types of activities are typical for

the area. 36

The State next indicates that the

greatest fraction of PM-Ia at the

Corcoran and Bakersfield sites on

September 22 consisted of particles in

the size fraction between PM-10 and

PM-2.5. 39 This information indicates

that geologic dust, as opposed to

secondary PM or PM from combustion

sources, was the primary contributor to

the exceedances. The-fraction of coarse

particles at Corcoran and Bakersfield on

September 22 was 89% and 79%

respectively. 40 These values must be

compared to the typical geologic values

for the Valley during September of

approximately 30 Igg/m 3 which are less

than 50% of the measured PM-10.4 1

Based-on the reported 89% value, the

estimated geologic material for Corcoran

was approximately 190 to 230 .g/m3 for

September 22, 2006. The corresponding

values for Bakersfield were 123-134.pg/

M 3

. Compared to the typical September

value of approximately 30 gig/m 3, the

September 22, 2006 values represent an

excess geologic contribution of

,approximately 160 to 200 gig/m3 for

Corcoran and approximately 94 to 104

for Bakersfield. If the typical value of 30

ig/m3 were used instead of the high

estimated geologic values derived from

the PM-10-2.5 size fraction, the.

resulting "adjusted" PM-1a values for

Corcoran and Bakersfield would be 50-

65 gg/m 3. This result favorably

compares to the typical average

September concentration of less than 60

ig/m 3. Allowing fer a PM-10 geologic

value of 60 jg/m3, which is twice the

September norm, would only yield an "adjusted" concentration of 84 to 96 gg/

M 3 . All of these sets of adjusted values

38NED for September 22, 2006 at 32-33.

391d. at 32, Figure 13. 40Id

41 Magliano Presentation.

for September 22 are consistent with the

aforementioned historical September

levels which rarely exceeded 100 gg/m 3 ,

showing that very few days in

Bakersfield and Corcoran over the

period 2000-2006 exceeded the level of

100 gg/m 3.

In addition, the NED for September

22, 2006 includes Table 2 that lists the

PM-10 24-hour average concentrations

recorded using continuous analyzers for

the days immediately preceding and

after September 22, 2006.42 This table

indicates that 24-hour average PM-10

concentrations at Corcoran were over

100% higher on September 22 as

compared to September 20, 21, 23, and

24. At Bakersfield, concentrations on

September 22 were over 100% higher

than on September 20 and September 24

and 86% higher than on September 21.

Compared to September 23 the increase

was 14%.

Finally, as discussed above, there

were reasonable and appropriate

measures in place to control PM-10 in

the SJV on September 22, 2006,

Regulation VIII and Rule 4550. 4 3

Moreover, EPA has approved the

District's BACM demonstration for all

significant sources of PM-la in the SJV

as meeting CAA section 189(b)(1)(B).44

Furthermore, District staff performed 46

inspections in the Valley on September

22 to ensure that regulated sources were

complying with the District's fugitive

dust rules. 4 5 The District's Natural

Events Action Plan, discussed below,

also addresses the reasonable and

appropriate measures that the District

has implemented to address high wind

events in the SJV.

Based on the weight of evidence

presented, EPA concludes that the

State's documentation demonstrates that

the exceedances at Corcoran, and

Bakersfield and Oildale on September

22, 2006 would not have occurred but

for the wind event on this day.

3. Mitigation Requirements

Under 40 CFR 51.930, a state

requesting to exclude air quality data

due to exceptional events must take

appropriate and reasonable actions,

including public notification, public

education,'and implementation of

measures, to protect public health from

exceedances or violations of the

NAAQS.

The SJVAPCD adopted the "Natural

Exvents Action Plan for High Wind

Events in the San Joaquin Valley Air

42 NED for September 22, 2006 at 9. 4 3

Id. at 32.

4469 FR 30006, 30035 (May 26, 2004); 71 FR 7683

(February 14, 2006). 45

NED for September 22, 2006 at 45-46.

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Basin" (NEAP) on February 16, 2006.

The NEAP provides the SJVAPCD's

approach to forecasting high wind

events, notifying the public prior to the

event and educating the public on how

to minimize exposure during high wind

events. The document also discusses

measures that are in place to help

minimize exposure to elevated PM-10

levels. EPA believes that the detailed

processes and measures described in the

NEAP satisfy the mitigation

requirements under 40 CFR 51.930.

a. Provide for Prompt Public

Notification of Exceedance Events

I Section 6 of the NEAP provides the

meteorological forecasting criteria that

the SJVAPCD uses to determine whether

or not to declare NEAP episodes. When

the criteria indicate that a NEAP

episode should be declared, the

SJVAPCD has a public notification

program, discussed in Section 7 of the

NEAP, which involves informing the

local media, SJVAPCD staff and

community groups.

b. Provide for Public Education on How

To Minimize Exposure

Section 7 of the NEAP provides a list

of precautions that can be taken to limit

exposure during a NEAP episode. The

list includes keeping windows shut,

using air conditioners or heaters on the

recycle/recirculating air mode, limiting

strenuous activity, and other

precautions. Section 8 of the NEAP

discusses the SJVAPCD's general'public

outreach program on NEAP episodes

which includes developing and

providing a brochure and information

about NEAP episodes by means of

community events, health fairs, schools

and civic engagements.

c. Provide for the Implementation of

Appropriate Measures To Protect the

Public

Section 10 of the NEAP discusses the

SJVAPCD's measdres that reduce PM-10

emissions. These measures, including

those approved by EPA as BACM for the

SJV, in combination with the

.SJVAPCD's process for declaring NEAP

episodes and educating the public on

how to minimize their exposure during

a NEAP episode, meet the requirements

for appropriate measures to protect the

public during high wind exceptional.

events.

Conclusion

EPA believes that the high winds in

the area of Lemoore on September 22,

2006 were an exceptional event as

defined in 40 CFR 50.1(j). EPA also

believes that the State has provided a

sufficientweight of evidence

demonstration to show that these high

winds generated and transported PM-10

from the area of Lemoore to Corcoran,

causing an exceedance of the 24-hour

PM-10 NAAQS. Winds between

Corcoran and the Bakersfield area were

sufficient to transport the dust that

originated in the Lemoore area such that

they caused the monitors at BakersfieldGolden State Highway and Oildale to

also exceed the NAAQS. The

documentation submitted by the State

demonstrates that but for the high winds

in the area of Lemoore, the Corcoran,

Bakersfield and Oildale monitors would

not have exceeded the 24-hour PM-10

NAAQS on September 22, 2006.

Because EPA believes that the State has

satisfied the provisions of the

Exceptional Events Rule, EPA proposes

to concur with the State's request to flag

these exceedances as being due to

exceptional events and to exclude the

data from consideration in determining

whether the area has attained the PM10 standard.

B. October 25, 2006 Exceedances at

Corcoran and Bakersfield

On October 25, 2006, the SJV

recorded exceedances of the 24-hour

PM-10 NAAQS at two sites, Corcoran

and Bakersfield-Golden State Highway,

using continuous PM-10 analyzers

designated as FEM monitbrs. 46 The 24-

hour average concentrations recorded

were 304 .g/m3 at Corcoran and 193 kg/ m 3 at Bakersfield-Golden State

Highway. The conditions that

contributed to these exceedances were

very similar to those that occurred on

September 22, 2006. Based on the

evidence submitted, EPA agrees with

the State's demonstration that high

wind-entrained dust from the central

and southern SJV caused the

exceedances at the two monitoring

locations on October 25, 2006.

1. Procedural Requirements

a. Data Are Flagged in EPA's AQS

Database

The October 25, 2006 exceedances

were flagged in EPA's AQS database as

of July 2007.

46 The District operates Tapered Element

Oscillating Microbalance (TEOM) continuous

automated analyzers at these two sites in addition

to the manual high-volume Federal Reference

Method (FRM) monitors. The FRMs operate at a less

than everyday schedule, as allowed by EPA

regulations, but neither of the FRM monitors was

operating on October 25, 2006. The District operates

the continuous analyzers so that they may report

daily PM-10 air quality data to the public.

b. Public Had an Opportunity To

Review and Comment on the State's

Documentation

In February 2007, the SJVAPCD

notified the public in local newspapers

and on its Web site of the availability of

the document entitled "Natural Event

Documentation, High Winds, Corcoran

and Bakersfield, California, October 25,

.2006," SJV Unified Air Pollution

Control District, February 2007 and

requested public comments by March 5,

2007.

The SJVAPCD subsequently revised

the February 2007 document and

submitted to CARB the "Natural Event

Documentation, Corcoran and

Bakersfield, California, October 25,

2006," San Joaquin Valley Unified Air

Pollution Control District, April 23,

2007 (NED for October 25, 2006), and

posted it on its Web site..

The SJVAPCD indicated that no

public comments were received during

its public process.

c. The Documentation Was Submitted to

Epa

The NED for October 25, 2006 was

submitted by the State to EPA on May

1, 2007 and is the document upon

which EPA is basing its evaluation

below.

d. EPA Concurs With the State's

Demonstration

In this proposed rule, EPA is

proposing to concur with the State's

demonstration in the NED for October

25, 2006 that high wind-entrained dust

caused the exceedances at the two

monitoring sites.

2. Technical Criteria

a. Did this event satisfy the criteria in

section 50.1(j) of the Rule?

i. Affected Air Quality

For an event to qualify as an

exceptional event, the state must show

that the event affected air quality. This

criterion can be met by establishing that

the event is associated with a measured

exceedance in excess of normal

historical fluctuations, including

background, and there is a causal

connection between the event and the

exceedance. The demonstration of a

clear causal relationship is necessary to

establish that the event affected air

quality and is also a separate statutory

requirement as discussed above.

In the NED for October 25, 2006, the

State provides documentation that the

measured exceedances recorded on

October 25, 2006 were in excess of

normal historical fluctuations. See

subsection c. below. The State also

establishes a causal connection between

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the high winds recorded at Lemoore and

the high concentrations at the monitors

recorded at Corcoran and Bakersfield.

The State's demonstration of the clear

causal relationship between the

exceptional event and the exceedances

on this day is discussed in greater detail

in subsection b. below.

ii. Not Reasonably Controllable or

Preventable

Section 50.1(j) requires that for an

event to qualify as an exceptional event,

whether natural or anthropogenic, a

state must show that the event was not

reasonably preventable or controllable.

Here this requirement is met by

demonstrating that despite reasonable

and appropriate measures in place, the

October 25, 2006 wind event caused the

exceedances. During this event, there

were no other unusual dust-producing

activities occurring in the SJV and

anthropogenic emissions Were

approximately constant before, during

and after the event. In addition, the

State showed that reasonable and

appropriate measures were in place,

including Regulation VIII (the District's

general fugitive dust rules) and Rule

4550 which limits fugitive dust

emissions specifically from agricultural

operations through Conservation

Management Practices. 47 Moreover, EPA

has approved the District's BACM

demonstration for all significant sources

of PM-10 in the SJV as meeting CAA

section 189(b)(1)(B). 48

iii. Was a Natural Event

In the preamble to the Exceptional

Events Rule, EPA states that ambient

particulate matter concentrations due to

dust being raised~by unusually high

winds will be treated as due to

uncontrollable natural events where (1)

the dust originated from

nonanthropogenic sources, or (2) the

dust originated from anthropogenic

sources within the State, that are

determined to have been reasonably

well-controlled at the time that the

event occurred, or from anthropogenic

sources outside the State. 72 FR at

13576. In the preamble EPA also

explains that "[sItates must provide

appropriate documentation to

substantiate why the level of wind

speed associated with the event in

question should be considered unusual

for the affected area during the time of

year that the event occurred." Id. at

13566.

The wind-entrained dust on October

25, 2006 originated from anthropogenic

sources within California, i.e., from

4 7

NED for October 25, 2006 at 29.

4869 FR at 30035; 71 FR 7683.

usual dust-generating activities such as

agricultural and industrial operations. 49

We discuss the fugitive dust control

measures in place in the SJV on October

25 above.

With respect to the wind speed, EPA

concurs with the State's demonstration

that the wind speeds in the central SJV

were unusually high on October 25,

2006.50 Table 1 of the NED for October

25, 2006 lists the wind speeds in the

Hanford and Lemoore areas. The peak

hourly averaged winds were in the

range of 29 to 31 mph at Lemoore,-with

gusts reaching 40 mph. Peak hourly

winds at Hanford were lower, in the

range of 17 to 18 mph, but still in line

with the threshold wind speed of 17.8

mph. Hanford also recorded peak gusts

of 22 to 30 mph during the 10 a.m. to

12 noon period.51 Tables 8, 9, and 11 of

the NED for October 25, 2006 also

include information on wind speeds

throughout the central valley of

California and the central and southern

SJV.52 The documentation also states

that wind speeds of these intensities are

relatively rare in the southwestern part

of the SJV and occur less than 5% of the

time, based on long-term monitoring

records. 53

EPA concurs with the State's

demonstration in the NED for October

25, 2006 that the wind speeds occurring

in the central SJV were unusually high

on October 25, 2006. While the winds

at Corcoran were not as high as those in

Lemoore and Hanford, as described in

the State's documentation, the winds at

Corcoran during the peak hourly PM-10

concentrations (8 a.m. to 11 a.m.) ranged

from 10to 13 mph, which are unusual

for this time of year in that 'rea. These

wind speeds, though not sufficient to

erode dust, were sufficient to keep the

entrained and transported dust from the

high winds at Lemoore suspended for

the period during which the

exceedances occurred.

iv. Determined by EPA To Be an

Exceptional Event

Finally, EPA must determine through

the process established in the

Exceptional Events Rule whether an

exceptional event occurred. We believe

that the State has met the procedural

requirements of the Rule including

flagging of the data, submission of

demonstration, evidence of the public

opportunity to review and comment on

the demonstration and mitigation

requirements as discussed at section

4

9 NED for October 25, 2006 at 29. 5 0 d. at sections 4 and 5.

51 Id. at 11.

5

2 Id. at 22-23.

53Id. at 24.

.V.B.1. and 3. of this proposed rule. We

further believe that the State has also

met the technical criteria of the Rule as

discussed at section V.B.2. of this

proposed rule. Therefore we are

proposing to concur with the State's

determination that an exceptional event,

i.e., a high wind event, occurred

resulting in the exceedances on October

25, 2006.

b. Does the State's documentation show

a clear causal connection between the

exceedances and the claimed

exceptional event?

Under 40 CFR 50.14(c)(3)(iii)(B), a

state's demonstration must establish a

clear causal relationship between the

measured exceedances and the claimed

exceptional event. In addressing this

requirement for the October 25, 2006

exceedances, the NED for October 25,

2006 submitted by the State identifies

the area northwest of Corcoran as the

source of PM-10 during the October 25,

2006 event. Winds in the Lemoore area

were again in excess of the threshold

wind speed for eroding and entrainingdust as discussed above. Table 1 of the

NED for October 25, 2006 shows a clear

correlation between the wind speeds in

the Hanford and Lemoore areas and the

increased hourly concentrations at

Corcoran. 54 In fact the peak wind speeds

at Lemoore and Hanford, which

occurred between 10 a.m. and 12 noon

at Lemoore, coincide with the peak

hourly concentrations at Corcoran. The

peak hourly averaged winds were in the

range of 29 to 31 mph at Lemoore, with

gusts reaching 40 mph. Peak hourly

winds at Hanford were lower, in the

range of 17 to 18 mph, but still in line

with the threshold wind speed of 17.8

mph. Hanford also recorded peak gusts

during the 10 a.m. to 12 noon period of

22 to 30 mph. Figure 2 of NED for

October 25, 2006 compares the hourly

wind speed and PM-10 concentration

data from Corcoran with the hourly

wind speed data from Lemoore in a

graphical format.5 5 This graphic shows

the almost perfect correlation between

increased wind speeds at Corcoran and

Lemoore with the increased PM-10

hourly concentrations at Corcoran.

The dust plume that iffected the

Corcoran monitoring site on October 25,

2006 continued moving south and

ultimately impacted the continuous

PM-10 analyzer operating at the

Bakersfield-Golden State Highway

monitoring site. The State provides

information on wind speed and

direction from the Alpaugh

meteorological monitoring station,

54 NED for October 25, 2006 at 11.

55 Id. at 12.

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located between Corcoran and

Bakersfield about 16 miles south

southeast of the Corcoran monitoring

site.56 Between the hours of 9 a.m. and

4 p.m., wind speeds at Alpaugh

averaged about 12 mph.5s Since the

meteorological data measured at

- Alpaugh is taken at 2 meters Above

Ground Level (AGL), the average wind

speed at 10 meters AGL is about 15

mph.5 8 EPA believes this average wind

speed would have been sufficient to

keep the dust plume suspended, and

that it facilitated the transport of the

dust plume to the Bakersfield area..

The data in Table 1 of the NED for

October 25, 2006 show the Bakersfield

hourly PM-10 concentrations beginning

to exceed the level of the 24-hour PM10 NAAQS at 11 a.m. (177 gg/m 3) and

peaking between the hours of 2 p.m. and

5 p.m. (415 gg/m 3 and 416 jig/m 3,

respectively). Figure 4 provides a graph

of PM-10 hourly concentrations for

three continuous PM-10 analyzers

operated by the District at Corcoran,

Bakersfield-Golden State Highway, and

Tracy.5 9 The graph shows hourly PM10 concentrations at Bakersfield-Golden

State Highway slowly increasing

through the morning hours of October

25 until 8 a.m. Hourly concentrations

increase at a higher rate between 8 a.m.

and 1 p.m., mirroring the increase at

Corcoran, but not as dramatic. As the

Corcoran hourly concentrations are

dropping between 11 a.m. 4 p.m. we see

a corresponding sharp increase in

hourly concentrations at BakersfieldGolden State Highway. This behavior of

the hourly concentrations supports the

State's explanation that the dust plume

that first affected Corcoran traveled

south over a period of several hours and

then impacted the Bakersfield monitor.

As with the September 22, 2006

event, the State includes for the October

25, 2006 event the results of a basic

meteorological model known as the

Hybrid Single-Particle Lagrangian

Integrated Trajectory model

(HYSPLIT).60 It is important to note that

while this modeling is not meant to

quantify the particle concentration,

recorded in the Bakersfield area, it does

supportthe State's demonstration that

the winds on October 25, 2006 were of

the appropriate intensity and- direction

to move a plume of dust from the

central SJV to the Bakersfield area.

5

6 d. at 22-26.

57M. at 58.

s5id. at 24-26.

59M. at 14.

6Old. at 27.

c. Did the State demonstrate that the

event is associated with measured

concentrations in excess of normal

historical fluctuations including

background?

For EPA to concur with a state's claim

that an exceptional event caused an

exceedance, one of the requirements

that the state must meet is to show that

the event is associated with

concentrations that are beyond the

normal historical fluctuations. See 40

CFR 50.14(c)(3)(iii)(C).

The State provides data on PM-10

levels on the days before and after

October 25, 2006, PM-10 concentrations

before and after October 25, 2006 were

significantly lower than the

concentration recorded on October 25,

2006. An EPA review of continuous

PM-IO data from Corcoran and

Bakersfield-Golden State Highway

showed that 24-hour average

concentrations from October 1, when

the TEOM continuous analyzers began

reporting data, through October 24 did

not exceed 100, and while there were a

number of higher concentrations on the

days after October 25, not counting the

exceedances recorded on December 8,

2006, which are discussed further below

in subsection d, the PM-10

concentrations at Corcoran and

Bakersfield-Golden State Highway fell

to mostly less than 100 again fromOctober 28 through June 30, 2007.61

Historically we can compare data

from these continuous analyzers only

with the separate manual FRM samplers

operated at the sites. When we look at

typical PM-10 concentrations recorded

in the month of October from 2000 to

2006 the maximum value recorded at

Bakersfield was 116 gg/m 3 measured on

October 16, 2001 and the maximum

non-exceedance value recorded at

Corcoran was 150 jg/m3 measured on

October 31, 2006.62 These

concentrations indicate that the

exceedances recorded on October 25,

2006 were unusual and not

representative of typical high

concentrations recorded at these

monitoring locations.

d. Did the State demonstrate that there

would have been no exceedance "but

for" the event?

As discussed previously, to qualify as

an exceptional event the State must also

demonstrate that there would have been

6 "Continuous PM-10 Data Collected with

TEOMs, Data Reported to EPA's AIRNOW

Website," July 30, 2007, Excel Spreadsheet, Bob

Pallarino. 62 Corcoran exceeded the 24-hour NAAQS on

October 29, 2002 with a value of 168 ptg/m3; PM10 Raw Data Reports, Corcoran 2000-2006 and

Bakersfield-Golden 2000-2006.

no exceedance "but for" the event. 40

CFR 50.14(c)(3}(iii)(D). To meet this

"but for" requirement, the state must

include analyses to demonstrate that an

exceedance or violation would not have

occurred but for the event. Such

analyses do not require a precise

estimate of the estimated air quality

impact from the event. 72 FR at 13570.

To meet this "but for" requirement

the State first shows that there were no

unusual activities occurring in the

affected areas in the Valley that could

have resulted in the exceedances,

Specifically, based on information from

District field staff and discussions with

representatives of agricultural and

industrial operations in the Valley,

anthropogenic emissions were

approximately constant in the Valley

immediately before, during and after the

event. The District staff observed no

unusual emissions other than those

associated with" the wind event. The

PM-10 generating activities were

BACM-controlled sources that are usual

for the area.63 District staff conducted 90

inspections throughout the SJV on

October 25 to ensure sources were in

compliance with District air pollution -

rules.64

The State notes in the NED for

October 25, 2006 that the PM-2.5 to

PM-10 ratio on this day was very low,

which indicates that mostly coarse PM

was present on the filter, supporting its

claim that the concentrations recorded

on this day were affected by a blowing

dust event.

65

When we examine the typical makeup of PM-10 in the SJV during October

we generally see particle concentrations

that are mostly in the size fraction of

PM-2.5, roughly 60-65%, with the

remaining mass being particles in the

PM-10-2.5 size fraction.66 Typically,

fugitive dust is the major constituent of

the PM-10-2.5 size fraction and makes

up about 25 to 35% of the total PM-10.

When we look at a comparison of PM2.5 and PM-10 concentrations recorded

on October 25, 2006, we find that the

PM-10-2.5 portion of the total PM-10

represents about 93% of the total PM10 at Corcoran and 85 percent of total

PM-10 at Bakersfield. This high

percentage of PM-10-2.5, which is

mostly fugitive dust, is atypical for this

time of year and supports the State's

demonstration that the PM-10

concentrations on this day consisted of

mostly coarse geologic material.

We can also look at the days

immediately preceding and following

63 NED for October 25, 2006 at 7 and 29.

4Id. at35.

r5I. at 28. 6 6 Magliano Presentation.

I

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the exceedance day to see if the

concentrations on October 25 were

unusual. The PM-10 concentrations

recorded on October 25 at Corcoran and

Bakersfield were over three times higher

than they were on October 24.67 PM-10

concentrations after the event decreased

dramatically and by October 28, PM-10

concentrations at both sites were below

100. See also the discussion of the

historical levels at these monitors set

forth in subsection c. above, which

further demonstrates that the

concentrations recorded on October 25

were unusual.

Finally, as discussed above, there

were reasonable and appropriate

measures in place to control PM-10 in

the SJV on October 25, 2006, Regulation

VIII and Rule 4550.68 Moreover, EPA

has approved the District's BACM

demonstration for all significant sources

of PM-10 in the SJV as meeting CAA

section 189(b)(1)(B). 69 Section 9.2 of the

NED for October 25, 2006 indicates that

the District staff performed 90

inspections on that date to ensure that

regulated sources were complying with

District fugitive dust rules.70 The

District's Natural Events Action Plan,

discussed in section V.A.3. above, also

addresses the reasonable and

appropriate measures that the District

has implemented to address high wind

events in the SJV.

Based on the weight of evidence

presented, EPA concludes that the

State's documentation demonstrates that

the exceedances at Corcoran and

Bakersfield on October 24, 2006 would

not have occurred but for the wind

event on this day.

3. Mitigation Requirements

See section V.A.3. above.

Conclusion

EPA believes that the high winds in

the area of Lemoore on October 25,

2006, were an exceptional event as

defined in 40 CFR 50.1(j). EPA also

believes that the State has provided a

sufficient weight of evidence

demonstration to show that these high

winds generated and transported PM-10

from the area of Lemoore to Corcoran,

causing an exceedance of the 24-hour

PM-IO NAAQS. Winds between

Corcoran and the Bakersfield area were

sufficient to transport the dust that

originated in the Lemoore area such that

they caused the monitor at BakersfieldGolden State Highway to also exceed

the NAAQS. The documentation

67NED for October 25, 2006 at 16, Table 3. 6 8 1d. at 29.

696 9 FR at 30035; 71 FR 7683. 70 NE for October 25, 2006 at 35.

submitted by the State demonstrates

that but for the high winds in the area

of Lemoore, the Corcoran and

Bakersfield monitors would not have

exceeded the 24-hour PM-10 NAAQS

on October 25, 2006. Because EPA

believes the State has satisfied the

provisions of the Exceptional Events

Rule, EPA proposes to concur with the

State's request to flag these exceedances

as being due to exceptional events and

to exclude the data from consideration

in determining whether the area has

attained the PM-10 standard.

C. December 8, 2006 Exceedances at

Corcoran and Bakersfield

The SJV recorded exceedances of the

24-hour PM-10 NAAQS on December 8,

2006 at two sites, Corcoran and

Bakersfield-Golden State Highway,

using continuous PM-10 analyzers

designated as FEM monitors. The 24-

hour average PM-10 concentrations

recorded were 162 lig/m 3 at Corcoran

and 213 gg/m 3 at Bakersfield-Golden

State Highway.

The State demonstrates that unusually

high winds in the Bakersfield area

eroded and entrained dust that

impacted the continuous PM-10

analyzer at Bakersfield. Unlike

September 22 and October 25, 2006, the

winds in the SJV on this day were

generally from the southwest, south and

southeast, transporting dust northward

and ultimately impacting the

continuous PM-10 analyzer at Corcoran.

Based on the evidence submitted, EPA

agrees with the State's demonstration

that high wind-entrained dust caused

the exceedances at the two monitoring

-locations on December 8, 2006.

1. Procedural Requirements

a. Data Are Flagged in EPA's AQS

Database

The December 8, 2006 exceedances

,were flagged in EPA's AQS database as

of July 2007.

b. Public had an opportunity to review

and comment on the State's

documentation

In February 2007, the SJVAPCD

notified the public in local newspapers

and on its Web site of the availability of

the document entitled "Natural Event

Documentation, High Winds, Corcoran

and Bakersfield, California, December 8,

2006," SJV Unified Air Pollution

Control District, February 2007 and

requested public comments by March 5,

2007.

The SJVACPD subseqluently revised

the February 2007 document and

submitted to the California Air

Resources Board (CARB) the "Natural

Event Documentation, Corcoran and

Bakersfield, California, December 8,

2006," SJV Unified Air Pollution

Control District, May 23, 2007 and

posted it on its Web site.

SJVAPCD thereafter made revisions

per CARB's request and submitted to

CARB the "Natural Event

Documentation, Corcoran and

Bakersfield, California, December 8,

2006," SJV Unified Air Pollution

Control District, June 6, 2007 (NED for

December 8, 2006) and posted it on its

Web site.

The District indicated that no public

comments were received during the

public process.

c. The Documentation Was Submitted to

EPA

The NED for December 8, 2006 was subsequently submitted by the State to

EPA on June 12, 2007 and is the

document upon which EPA is basing its

evaluation below.

d. EPA Concurs With the State's

Demonstration

In this proposed rule, EPA is

proposing to concur with the State's

demonstration in the NED for December

8, 2006 thfat high wind-entrained dust

caused the exceedances at the two

monitoring locations on December 8,

2006.

2. Technical Criteria

a. Did this event satisfy the criteria in

section 50.1(j) of the Rule?

As with the previous events discussed

in this proposed rule, the State needs to

show that this event, identified in the

NED for December 8, 2006 as unusually

high winds, affected air quality in the

Corcoran and Bakersfield areas, was not

reasonably controllable or preventable, was a natural event, and is determined

by EPA to be an exceptional event.

i. Affected Air Quality

For an event to qualify as an exceptional event, the state must show

that the event affected air quality. This

criterion can be met by establishing that

the event is associated with a measured

exceedance in excess of normal

historical fluctuations, including

background and there is a causal

connection between the event and the

exceedance. This demonstration of a causal connection is necessary to

establish that the event affected air

quality and is also a separate statutory

requirement as discussed above.

In the NED for December 8, 2006, the

State provides documentation that these

measured exceedances were in excess of

normal historical fluctuations. See

subsection c. below. The State also

establishes a causal connection between

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the high winds recorded in the

Bakersfield and Southern SJV area and

the high concentrations recorded at the

Corcoran and Bakersfield monitors. The

State's demonstration of the clear causal

relationship between the event and the

exceedances on this day is discussed in

greater detail in subsection b. below.

ii. Not Reasonably Controllable or

Preventable

Section 50.1 (j) of the Exceptional

Events Rule requires that for an event to

qualify as an exceptional event, whether

natural or anthropogenic, a state must

show that the-event was not reasonably

preventable or controllable. Here this

requirement is met by demonstrating

that despite reasonable and appropriate

measures in place, the December 8, 2006

wind event caused the exceedances.

During this event, there were no other

unusual dust-producing activities

occurring in the SJV and anthropogenic

emissions were approximately constant

before, during and after the event. In

addition, the State shows that

reasonable and appropriate measures

were in place, including Regulation VIII

(the District's general fugitive dust

rules) and Rule 4550 which limits

fugitive dust emissions specifically from

agricultural operations through

Conservation Management Practices. 71

Moreover, EPA has approved the

District's BACM demonstration for all

significant sources of PM-10 in the SJV

as meeting CAA section 189(b)(1)(B). 72

iii. Was a Natural Event

In the preamble to the Exceptional

Events Rule, EPA states that ambient

particulate matter concentrations due to

dust being raised by unusually high

winds will be treated as due to

uncontrollable natural events where (1)

the dust originated from

nonanthropogenic sources, or (2) the

dust originated from anthropogenic

sources within the State, that are

determined to have been reasonably

well-controlled at the time that the

event occurred, or from anthropogenic

sources outside the State. 72 FR at

13576. In the preamble EPA also

explains that "[sitates must provide

appropriate documentation to

substantiate why the level of wind

speed associated with the event in

question should be considered unusual

for the affected area during the time of

year that the event occurred." Id. at

13566.

On December 8, 2006, the windentrained dust originated from

anthropogenic sources within

71 NED for December 8, 2006 at 25. 7269 FR at 30035; 71 FR 7683.

California, i.e., from usual dust- -

generating activities such as agricultural

and industrial operations. 73 We discuss

the fugitive dust control measures in

place in the SJV on December 8, 2006

above.

With respect to the wind speed, EPA

concurs with the State's demonstration

that the wind speeds in the southern

SJV were unusually high on December

8, 2006. The State includes information

on the unusual nature of the windspeeds in the SJV on December 8, 2006,

stating that winds of these magnitudes

are rare, occurring less than 5% of the

time. The NED for December 8, 2006

reports that during the blowing dust

event, Bakersfield reported winds up to

25 mph with gusts up to 35 mph.

Farther north in the area of Kettleman

Hills, located on the west side of the

San Joaquin Valley, gusts up to 50 mph

were reported. Kettleman Hills also

reported a twenty-two hour period with

gusts of 20 mph or greater (from 6 a.m.

on December 8, 2006 to 4 a.m. on

December 9, 2006). Maricopa, located

on the southwest side of the San Joaquin

Valley approximately 25 miles

southwest of Bakersfield, reported a

one-minute average wind speed of 56

mph.74

iv. Determined by EPA To Be an

Exceptional Eevent

Finally, EPA must determine through

the process established in the

Exceptional Events Rule whether an

exceptional event occurred. We believe

that the State has met the procedural

requirements of the Rule including

flagging of the data, submission of

demonstration, evidence of the public

opportunity to review and comment on

the demonstration and mitigation

requirements as discussed at section

V.C.1. and 3. of this proposed rule. We

further believe that the State has also

met the technical requirements of the

Rule as discussed at section V.C.2.

Therefore, we are proposing to concur

with the State's determination that an

exceptional event, i.e., a wind event,

occurred resulting in the exceedances

on December 8, 2006.

b. Does the State's documentation show

a clear causal connection between the

exceedances and the claimed

exceptional event?

Under 40 CFR 50.14(c)(3)(iii)(B), a

state's demonstration must establish a

clear causal relationship between the

measured exceedances and the claimed

exceptional event. Unlike September 22

and October 25, 2006, the winds on

73 NED for December 8, 2006 at 25.

74 Id. at 17.

December 8, 2006 were erratic and

generally from the east, south, and

southwest.75 Wind speeds at

meteorological stations near Bakersfield

recorded hourly average wind speeds in

excess of 35 mph and wind gusts in

excess of 50 mph..Winds at Bakersfield

on December 8 were from both the

southwest and southeast during the time

when peak hourly PM-10

concentrations were recorded. The

winds continued to blow from the

southeast up the Valley, pushing the

dust plume towards the Corcoran

monitoring site. The peak hours for

hourly PM-10 concentrations were from

1 p.m. to 3 p.m. at both the Corcoran

and Bakersfield sites, with a second set

of high hourly concentrations at

Bakersfield occurring from 5 p.m. to 8

p.m. Winds measured at Alpaugh,

located between Bakersfield and

Corcoran, were highest from 12 p.m. to

4 p.m. and from the southeast,

supporting the State's argument that the

dust plume moved from the southeast to

northwest.76

Table 3 and Figure 2 of the NED for

December 8, 2006 77 show the

correlation of wind speeds and

increasing hourly concentrations of PM10 recorded by the continuous PM-10

analyzers at Corcoran and Bakersfield.

Figure 7 of the NED for December 8,

2006 includes the results of a basic

meteorological model known as Hybrid

Single-Particle Lagrangian Integrated

Trajectory model (HYSPLIT). 7 It is

important to note that while this

modeling is not meant to quantify the

particle concentration recorded in the

Bakersfield and Corcoran areas, it does

offer support of the State's

demonstration that the winds on

December 8,.2006 were of the

appropriate intensity and direction to

move a plume of dust from the

southeastern SJV to the Bakersfield area

and northward to Corcoran.

c. Did the State demonstrate that the

event is associated with measured

concentration in excess of normal

historical fluctuations including

background?

For EPA to concur with a state's claim

that an exceptional event caused an

exceedance, one of the requirements

that the state must meet is to show that

the event is associated with

concentrations that are beyond the

normal historical fluctuations. See 40

CFR 50.14(c)(3)(iii)(C).

75 Id. at 11, Table 3. 76 Id. at 56. 77 Id. at 11-12. ':

78 I . at.2 3". 'i ,u " ! I

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As with the discussion above on the

September 22 and October 25, 2006

exceedances, we can compare data from

the continuous analyzers only with the

separate manual FRM samplers operated

at the sites, since the continuous

analyzers have only been in operation

since late 2006. Figures 8 and 9 of the

NED for December 8, 2006 demonstrate

the relative infrequency, over the last 10

years, of the concentrations recorded at

Corcoran and Bakersfield on December

8, 2006. When we look at PM-10 FRM

concentrations recorded at Corcoran in

the month of December from 1997 to

2006, the last non-flagged exceedance of

the standard was a 174 recorded on

December 17, 1999. 79 Levels exceeding

100 only occurred 10 times in December

in the past 10 years, out of 96 FRM days

sampled. Even when we include the

continuous daily data collected at

Corcoran in 2006, there are only the 10

values over 100 described above.

For Bakersfield, the last non-flagged

day exceeding the standard in December

was 159 recorded on December 30,

1998. Of the 42 December FRM sample

days since 1997, 9 days exceed 100.

Again, even when we include the

continuous daily data from 2006, the

result remains 9 days exceeding 100 in

the last 10 years. 80

d. Did the State demonstrate that there

would have been no exceedance "but

for" the event?

As discussed above, to qualify as an

exceptional event the state must also

demonstrate that there would have been

no exceedance "but for" the event. 40

CFR 50.14(c)(3)(iii)(D). To meet this

"but for" requirement, the state must

include analyses to demonstrate that an

exceedance or violation would not have

occurred but for the event. Such

analyses do not require a precise

estimate of the estimated air quality

impact from the even. 72 FR at 13570.

To meet this "but for" requirement

the State first shows that there were no

unusual activities occurring in the

affected areas in the Valley that could

have resulted in the exceedances.

Specifically, based on information from

District field staff and discussions with

representatives of agricultural and

industrial operations in the Valley,

activities that generate anthropogenic

PM-10 were approximately constant in

the Valley immediately before, during

and after the event. As on September 22

and October 25, 2006, activity levels in

the SJV were typical for the time of year

79 PM-10 Raw Data Report Corcoran 1997-2006,

EPA AQS Database, July 30. 2007.

BoPM-10 Raw Data Report Bakersfield Golden

1997-2006, EPA AQS Database, July 30, 2007.

and PM-10 emission control programs

were being implemented, not only for

fugitive dust-generating activities, but

also agricultural burning and residential

wood combustion in parts of the SJV.81

The State provides frequency

distributions of the maximum PM-10

24-hour December concentrations for

the past 10 years. These figures indicate

that PM-10 concentrations at Corcoran

and Bakersfield-Golden State Highway

rarely exceeded the level of the 24-hour

PM-10 NAAQS. 82 This fact is an

indication that December 8, 2006 was

unusual in that the normal emission

activity levels do not cause

exceedances, based on historical data.

Examining the make-up of PM-10 on

this day using PM-2.5 data collected at

the sites with a continuous PM-2.5

analyzer, we can see that coarse

particles, or PM-10-2.5, which are

associated with windblown dust,

represented 78% of the total PM-10

mass collected at Corcoran and 88% of

the total PM-10 mass at Bakersfield.

CARB studies indicate that at this time

of year, fugitive dust generally

contributes less than 20% of the total

PM-10 mass. 83 The atypical

contribution of fugitive dust. to the

exceedances recorded on December 8,

2006 indicates that but for the wind

event these exceedances would not have

occurred.

As discussed above, the State also

looked at data from the days

immediately preceding and after

December 8, 2006.84 Twenty-four hour

PM-10 concentrations on December 4-

6 were less than 100 gg/m3 at both sites

and were just over 100 gg/m 3 on

December 7. On December 8, the

concentration at Corcoran increased by

more than 50%, exceeding the NAAQS

with a level of 162 tg/m3, but then fell

to 32 9g/M 3 on December 9 and

continued dropping for weeks after this

event. At Bakersfield, on December 8

there was a greater than 100% increase

over the December 7 concentration.

Again, concentrations dropped

dramatically on December 9 and

remained low for weeks after.

Finally, as discussed above, there

were reasonable and appropriate

measures in place to control PM-10 in

the SJV on December 8, 2006,

Regulation VIII and Rule 4550. 85

Moreover, EPA has approved the

District's BACM demonstration for all

significant sources of PM-10 in the SJV

81 NED for December 8, 2006 at 25.

82 Id. at 28-29, Figures 8 and 9. 83 Magliano Presentation.

84 NED for December 8, 2006 at Table 1.

8sW. at 25. "

as meeting CAA section 189(b)(1)(B). 86

The District's Natural Events Action

Plan, discussed in section V.A.3. above,

also addresses the reasonable and

appropriate measures that the District

has implemented to address high wind

events in the SJV.

Based on the weight of evidence

presented, EPA concludes that the

State's documentation demonstrates that

the exceedances at Corcoran and

Bakersfield on December 8, 2006 would

not have occurred but for the wind

event on this day.

3. Mitigation Requirements

See section V.A.3.c above.

Conclusion

EPA believes that the high winds in

the southeastern SJV on December 8,

2006 were an exceptional event as

defined in 40 CFR 50.1(j). EPA also

believes that the State has provided a

sufficient weight of evidence

demonstration to show that these high

winds generated and transported PM-10

from the area of Bakersfield to Corcoran

causing exceedances of the 24-hour PM10 NAAQS at the Bakersfield and

Corcoran monitors. The NED for

December 8, 2006 submitted by the

State demonstrates that but for the high

winds in the southern SJV, the Corcoran

and Bakersfield monitors would not

have exceeded the 24-hour PM-10

NAAQS on December 8, 2006. Because

EPA believes that the State has satisfied

the provisions of the Exceptional Events

Rule, EPA proposes to concur with the

State's request to flag these exceedances

as due to exceptional events and to

exclude the data from consideration in

determining whether the area has

attained the PM-10 standard.

VI. EPA Evaluation of September 14,

September 20 and October 26, 2006

Exceedances at the Santa Rosa

Rancheria

The 24-hour PM-10 NAAQS was

exceeded on September 14, 20 and

October 26, 2006 at a monitor on the

Santa Rosa Rancheria (SRR), tribal land

located in Kings County within the SJV.

The 24-hour average PM-la

concentrations were 190 pg/m3 , 158

M3 , and 157 tig/m 3, respectively. The

SRR Tribe flagged the exceedances as

caused by an exceptional event, i.e.,

construction activities.

The Santa Rosa Rancheria EPA

Department (SRREPA) operates a

monitoring site on the SRR, located on

the roof of a pumping station at the

SRR's water treatment facility. The PM10 sampler is a high volume size

8869 FR at 30035; 71 FR 7683.

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selective inlet (SSI) Anderson sampler

designated as a FRM by EPA. The

monitoring site also measures ozone and

meteorological parameters including

wind speed and wind direction.

The PM-10 sampler is located near

the northeast corner on the roof of the

pumping station. The current land cover

around the pump station is paved

parking. There are no obstructions of

any kind and there is unrestricted

airflow 360 degrees around the sampler

inlet.87

To the east of the monitor is a paved

parking lot, beginning about 25 feet east

of the monitor location and extending

approximately 50 feet to the east.

Beyond the parking area are trailers and

undeveloped land. To the north of the

monitor is a larger parking lot,

beginning about 100 feet north of the

monitor location and extending north

approximately 525 feet. Beyond the

parking lot are a casino hotel, casino,

and additional parking lots. To the

immediate south (150 feet) and west

(300 feet) are the remaining physical

plant facilities (tanks, pumps, etc.) and

the area is paved. Further south and

west are agricultural fields (currently

alfalfa). Agricultural -fields also lie to the

north beyond the casino and parking lot

(approximately 0.5 mile). To the east is

the SRR residential area. PM-10 is measured once-in-every-six

days by the SRREPA according to the

national sampling schedule. Sampling

began on August 3, 2006 and continues

to the present time.

In 2006 there was a major

construction project at the SRR, which

involved construction of a casino hotel

and associated parking lots. This

construction activity, located near the

monitor, was ongoing prior to the time

the monitor began operation. The

original intention of the SRREPA was to

begin operation of the monitor and

sampling only after completion of the

parking lots and external portion of the

'hotel. Due to delays, however, the

construction was not completed until

November 2006. The monitor began

operating as scheduled on August 3,

2006.

The SRREPA's environmental

technician informed EPA that he

believes that many of the samples

collected since PM-10 monitoring began

on August 3, 2006, through midNovember 2006, were unduly

influenced by the grading and paving of

parking lots immediately adjacent to the

monitoring site on the north and east

sides of the pump station building

a7July 18, 2007 Memorandum, "On-Site Visit to

Santa Rosa Rancheria," from Bob Pallarino, EPA, to

Sean Hogan, EPA (Site Visit Memorandum).

where the PM-IO sampler monitor is

located. a

8 In addition to the exceedance

days, much of the data between August

3 and November 25, 2006 submitted to

the AQS database, has been flagged as

affected by construction activity8 9

EPA believes there are two bases for

excluding the September 14, September

20 and October 26, 2006 exceedances

from consideration in determining

whether the SJV has attained the PM10 standard. First, as explained in more

detail below, EPA believes that, during

the time period the monitor was

operating in such close proximity to the

construction, the monitor should be

considered to have been improperly

sited under the principles established in

40 CFR part 58, appendix E. Second,

EPA believes that, under its Exceptional

Events Rule, the construction activity

that occurred within such close

proximity to the monitor constitutes an

exceptional event that caused the

exceedances. EPA believes that both of

these rationales, separately or together,

support EPA's proposal not to include

the SRR monitor data recorded during

the period of parking lot construction in our determination of whether the SJV

has attained the PM-10 NAAQS.

A. Evaluation Under Principles

Established in 40 CFR Part 58,

Appendix E

40 CFR part 58 establishes criteria and

requirements for ambient air quality

monitoring, and appendix E sets forth

the probe and monitoring path siting

criteria for ambient air quality

monitoring. 71 FR 61236 (October 17,

2006). These include both binding

requirements and goals. Section 1(b) of

appendix E, the Introduction, provides

that "[t]he probe and monitoring path

siting criteria discussed in this

appendix must be followed to the

maximum extent possible." Section

58.20 provides that Special Purpose

Monitors, which may include monitors

on tribal lands, must meet certain

requirements of.part 58, including

appendix E, -if the data they collect are

to be used for purposes of comparison

to the NAAQS. It is not clear whether

the monitor in Santa Rosa Rancheria is

intended to be designated a Special

Purpose Monitor. It is clear, however,

that EPA does not intend data from a

monitor to be used for purposes of

comparison to the NAAQS unless the

data meet the criteria set forth in section

58.20, including appendix E. Under the

principles established in part 58,

appendix E, EPA believes that it is not

88 Site Visit Memorandum. 8

9 AQS Raw Data Report, Santa Rosa Rancheria

PM-10 2006 to 2007.

a reasonable monitoring practice to

locate a PM-10 monitor, intended for

purposes of comparison to the NAAQS,

so close to an obviously temporary dust

source, as was the case at the SRR.

Section 3(a) of appendix E, Spacing

from Minor Sources, addresses the

siting of monitors, including PM-10

monitors. It states that close spacing

between a monitor and a minor source

may be proper if the purpose of that

monitoring site is to investigate

emissions from that source and other

local sources. However, if, as is the case

with the SRR monitor here, the site is

to be used to determine air quality over

a larger area, such as a neighborhood or

city, it should not be placed near local,

minor sources, because the plume from

the local minor source would

inappropriately impact the air quality

data collected at the site. It is plain that

this occurred in the SRR situation,

where the monitor, when it began

operating, was only 25 feet from one

parking lot construction zone and 100

feet from another.

We believe that in general it is

important to avoid placing a particulate

monitor inordinately close to a location

where active but temporary construction

activity is generating dust emissions. As

noted above, the SRREPA originally had

not intended to start operating the

monitor until after the conclusion of the

construction activity. As a consequence

of monitoring while this construction

was still ongoing, the SRR Tribe was

compelled to flag data for 12 of the 19

sampling days that occurred between

August 3 and November 25, when the

construction concluded. Thus more

than 60% of the data collected during

this time period was considered to be

unusable for regulatory purposes.

The dramatic contrast between

concentrations monitored while

construction was ongoing and postconstruction concentrations also

testifies to the impact that the improper

siting had on the monitored data. After

construction ceased, average monitored

PM-10 concentrations declined 50%.

See discussion below in section

VI.B.2.d. below. EPA believes that after

the construction concluded the monitor

met the appropriate siting criteria. 90

EPA has concluded that under the

very unusual circumstances presented

in the SRR, it was not appropriate,

according to the principles established

in part 58 appendix E, to deploy a new

PM-10 monitor, for purposes of

comparison to the NAAQS, so close to

temporary construction activity, for the

duration of that activity. EPA believes it

would be unreasonable for the Agency

90 Site Visit Memorandum.

I

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to allow the data from such a monitor

to determine the attainment status of th

Siv.

Conclusion

EPA is proposing to conclude that th(

exceedances in the SJV at the SRR

monitor that occurred on September 14

2006, September 20, 2006 and October

26, 2006 should be excluded from

consideration in determining whether

the SJV has attained the PM-10

standard, because during this time

period EPA deems that the monitor waE

not properly sited, under the principles

established in part 58, appendix E.

In proposing to find that, during the

period of construction, the monitor was

not properly sited for the purpose of

comparison to the NAAQS, EPA is

addressing only the particular facts and

circumstances presented by the SRR

monitoring operation. EPA notes that

the construction activity at the SRR,

which occurred in extremely close

proximity to the monitor and on tribal

land, predated the start of monitoring

operation.s, and that monitoring was

originally intended to begin only after

the conclusion of construction activity.

Under these circumstances, EPA

believes that the September 14,

September 20 and October 26, 2006

exceedances should be excluded from

consideration in determining whether

the SJV has attained the PM-10

standard.

B. Evaluation Under the Exceptional

Events Rule

In addition to the rationale regarding

the siting of the monitor, set forth abovt

EPA proposes to concur with the SRR

Tribe's flagging of the exceedances at

the SRR because EPA believes that the

construction activity constitutes an

exceptional event under EPA's

Exceptional Events Rule. Our

application of the requirements of the

Rule to the SRR exceedances is set fort

below.

1. Procedural Requirements

a. Data Are Flagged-in EPA's AQS

Database

The three exceedances were flagged

by the SRR Tribe by the time the data

were submitted to the AQS database in

2006.

b. Public Had an Opportunity To

Review and Comment on the Tribe's

Documentation

EPA is assisting the SRR Tribe by

compiling and evaluating the

documentation for the exceedances

which have been flagged as being

caused by exceptional events. The

Exceptional Events Rule recognizes thai

.tribes may not be in a position to

e address all of the requirements of the

Rule and thus states that EPA will

"* * * work with tribes on the

implementation of this rule, which may

inclde appropriate implementatioii by

EPA of program elements ensuring that

any exclusion * * * of data in Indian

country with air quality affected by

exceptional events comports with the

procedures and requirements of this

rule." 72 FR at 13563. EPA, through this

proposed rule, is providing the public

with an opportunity to review and

comment on the documentation of these

exceptional events.

c. The Documentation Was Submitted to

EPA

As discussed above, EPA is assisting

the SRR Tribe by compiling and

evaluating the documentation of the

exceedances which they have flagged as

being caused by exceptional events.

d. EPA Concurs With the Tribe's

Flagging and Demonstration

EPA is proposing to concur with the

SRR Tribe's flagging of these

exceedances as affected by exceptional

events. As discussed above, EPA is

assisting the SRR Tribe by compiling

and evaluating the documentation of the

&xceedances it has flagged as being

caused by exceptional events, and by

ensuring that the public has an

opportunity, through this rulemaking, to

review and comment upon it.

2. Technical Criteria

a. Did this event satisfy the criteria in

section 50.1(j) of the Rule?

i. Affected Air Quality

For an event to qualify as an

exceptional event, the state or tribe must

show that the event affected air quality.

Here, EPA, on behalf of the SRR Tribe,

needs to show that the event, identified

as construction activity, affected air

quality at the SRREPA PM-10 monitor.

This criterion can be met by establishing

that the event is associated with a

measured exceedance in excess of

normal historical fluctuations, including

background, and there is a causal

connection between the event and the

exceedance, This demonstration of a

causal connection is necessary to

establish that the event affected air

quality, and it is also a separate

statutory requirement as discussed

above.

Because the SRREPA PM-10 monitor

has been in operation only since August

2006, it is not possible to compare the

data from exceedance days to historical

levels. In this case, however, we can

look at data that have been collected

since the construction and parking lot

paving was completed to determine

representative concentrations of PM-10

in the absence of a large, earthdisturbing project such as the

construction, grading and paving of

parking lots. We discuss the range of

data and its fluctuation in more detail

in subsection c. below.

We also need to show the causal

connection between the exceptional

event, in this case construction activity,

and the exceedances recorded. In

addition to other information provided

during EPA's on-site visit, the SRREPA

has provided EPA with wind speed and

wind direction data collected at its site

that show the wind was blowing in the

appropriate direction and demonstrates

that the PM-10 monitor was downwind

of the construction activity on the

exceedance days. We discuss the causal

connection between the construction

activity and the exceedances in more

detail in subsection b. below.

ii. Not Reasonably Controllable or

Preventable

Section 50.1(j) of the Exceptional

Events Rule requires that for an event to

qualify as an exceptional event, whether

natural or anthropogenic, a state, tribe

(or, in this case, EPA) must show that

the event was not reasonably

preventable or controllable.

EPA believes that it would not -ave

been reasonable to prevent the activity,

i.e., paving of parking lots that were

needed for the SRR Tribe's facilities.

Paving a parking lot (which involves

grading the ground, applying a base

material such as gravel and applying

asphalt) is a generally accepted form of

control of PM-10.91 To prevent the

paving of a parking lot would not only

be unreasonable, but illogical.

With respect to whether the event was

reasonably controllable, we note that the

SRR Tribe does not have PM-I control

measures in place and is not subject to

the fugitive dust control regulations

adopted by the SJVAPCD. As discussed

in the Exceptional Events Rule, "Tribes

are not required to develop TIPs or

otherwise implement relevant programs

under the CAA. * * *" 92 "EPA

recognizes Tribal Governments as

sovereign entities with primary

authority and responsibility for the

reservation populace. Accordingly, EPA

will work directly with Tribal

Governments as the independent

91 See, for example, SJV.Rule 8051 Open Areas

(Adopted November 15, 2001; Amended August 19,

2004) and Rule 8071 Unpaved Vehicle/Equipment

Traffic Areas (Adopted November 15, 2001;

Amended September 16, 2004). 0263 FR 7254, 7265 (February 12, 1998); 72 FR

at 13563.

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authority for reservation affairs, and not

as political subdivisions of States or

other governmental units." 93

While paving itself is a control

measure, EPA recognizes that other

control measures may bq reasonable

during a paving process. For example,

the SJVAPCD regulations require,

among other things, that regulated

construction sites apply-as appropriate

water or chemical/organic stabilizers or

construct and maintain wind barriers.9 4

In the circumstances of the SRR,

however, even if these types of

measures had been actively employed,

we cannot be certain that they would

have prevented exceedances at the PM10 monitor. This is due in large part to

the unusual circumstance presented

here of the very close proximity of the

construction activity to the monitor. As

noted above, one of the parking lots was

within 25 feet of the monitor, and the

other was within 100 feet.

EPA's evaluation of the parking lot

construction activity's impact on the

monitor, and whether it was reasonably

controllable, during the activity, is

informed by EPA's views on what

constitutes acceptable monitor siting. As

EPA has set forth in detail above, EPA

believes that, for the duration of the

construction activity, the monitor was

not properly sited for the purposes of

determining attainment of the SJV, and

that as a result it was inordinately

impacted by that activity.

The provisions of 40 CFR part 58,

appendix E regarding the siting of PM10 mohitors, are instructive with respect

to EPA's analysis of the exceedances

under the Exceptional Events Rule. We

cannot conclude that the activity was

reasonably controllable given that the

exceedances were measured at a

monitor that EPA's rule provides should

not be operated at such a time and

place, for the purposes of determining

attainment. Thus, under .the particular

set of circumstances presented here, for

the purposes of evaluating the

"reasonably controllable" criterion of

the-Exceptional Events Rule, we deem

this criterion to have been satisfied.

iii. Was an Event Caused by Human

Activity That is Unlikely to Recur at a

Particular Location

In this case, the event was paving of

parking lots in the vicinity of the PM10 monitor, and is a construction

activity that is not expected to recur at

that location.

9359 FR 43956 (August 25, 1994).

94 SJV Rule 8021 Construction, Demolition,

Excavation, Extraction, and Other Earthmoving

Activities (Adopted November 15, 2001; Amended

August 19, 2004).

iv. Deterjnined by EPA To Be an

Exceptional Event

Finally, EPA must determine through

the process established in the

Exceptional Events Rule whether an

exceptional event occurred. The

Exceptional Events Rule has both

procedural requirements and technical

criteria that we are assisting the

SRREPA in meeting. We believe that by

the initial flagging of the data, and

through the vehicle of this proposed

rulemaking we will demonstrate that the

procedural requirements and technical

criteria of the rule will have been met.

b. Is there a clear causal connection

between the exceedances and the

claimed exceptional event?

- Under 40 CFR 50.14(c)(3)(iii)(B), a

clear causal relationship must be

- established between the measured

exceedance and the claimed exceptional

event. The information compiled by

EPA shows a clear causal connection

between the exceedances and the

construction activity at the nearby'

parking lots. The SRREPA

environmental technician observed the

conditions at the time the monitor was

operating and noted on the sample

tracking forms, which are completed

with each sampling run, that there was

construction nearby. Copies of these

tracking forms are included in the

documentation for this rulemaking.

The SRREPA measures wind speed

and wind direction at the SRR

monitoring site. These meteorological

data indicate that on the three days that

exceeded the NAAQS, winds were

predominantly from the northwest to

northeast. This would indicate that any

dust-producing activity north and

northeast of the monitor would result in

high concentrations of geologic dust

being blown towards the monitor.

The meteorological data lend support

to the environmental technician's

account of the events of that day. EPA

also discussed these events with the

SRR construction superintendent, Who

agreed with the environmental

technician's account of the construction

activity. A private consultant working

for the SRREPA also stated that he had

witnessed major earth-disturbing

activities on these days.9a

Based on the meteorological data,

eyewitness accounts, and an on-site

inspection of the monitoring site

location and its proximity to the parking

lots, we believe that there was a clear

causal connection between the

construction activity and the recorded

PM-10 exceedances.

95 Site Visit Memorandum.

c. Can it be demonstrated that the event

is associated with a measured

concentration in excess of normal

historical fluctuations including

background?

For EPA to concur with the SRREPA's

claim that an exceptional event caused

an exceedance, one of requirements is to

show that the event is associated with

concentrations that are beyond the

normal historical fluctuations. See 40

CFR 50.14(c)(3)(iii)(C).

Of the 44 samples colleeted by the

SRREPA, nearly 80% of the samples (35

days) were less than 100 gg/m 3 . After

completion of the paving projects in

mid-November, 2006, average PM-10

concentrations dropped by more than

50%, from an average of 97 jig/m3 to an

average of 45 gg/m3. 96 This would

indicate that the construction activity

had an obvious effect on the

concentrations recorded by the SRR

monitor and that the data collected

during this construction period,

including the exceedances recorded in

September and October, 2006, were not

representative of typical postconstruction PM-10 concentrations at

the location of the monitor.

d. Can it be demonstrated that there

would have been no exceedance "but

for" the event?

To qualify as an exceptional event,

there must be an analysis which

demonstrates that there would have

been no exceedance "but for" the event.

40 CFR 50.14(c)(3)(iii)(D). Such analyses

do not require a precise estimate of the

estimated air quality impact from the

event. 72 FR at 13570.

To meet this requirement, EPA

believes the SRREPA environmental

technician, consultant and the SRR

construction superintendent have

clearly indicated that the exceedances

occurred on days where nearby

construction was also occurring. As EPA

has shown, the proximity of the monitor

to the construction activity and the

concomitant infeasibility of control

measures to prevent the exceedances

also demonstrate that there would have

been no exceedances but for the

construction activity. Given these

factors and the fact that the average PM10 concentrations dropped by more than

50% after the completion of the paving

projects, we believe the weight of

evidence shows that the exceedances

would not have occurred but for the

construction activity.

96 Santa Rosa Rancheria PM-10 24 hour average

concentrations, Excel spreadsheet, Bob Pallarino.

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3. Mitigation Requirements

Under 40 CFR 51.930, a state or tribe

requesting to exclude air quality data

due to exceptional events must take

appropriate and reasonable actions,

including public notification, public

education and implementation of

measures, to protect public health from

exceedances or violations of the

NAAQS. In the case of the SRR, EPA

recognizes that tribes may implement

only portions of air quality programs

and not be in a position to address each

of the procedures and requirements

associated with excluding or

discounting data. In the preamble to the

Exceptional Events Rule, EPA cites an

example of tribes that"* * * may

operate a monitoring network for

purposes of gathering and identifying

appropriate data, but may not

implement relevant programs for the

purpose of mitigating the effects of

exceptional events. * * " 72 FR at

13563. That is the case with the SRR.

Under these circumstances, as indicated

in the preamble to the Exceptional

Events Rule, EPA intends to work with

the SRR on the implementation of the

Rule.

Conclusion

EPA believes that the construction

activities at the SRR on September 14,

2006, September 20, 2006 and October

26, 2006 were exceptional events as

defined under 40 CFR 50.1(j). EPA

believes that there is sufficient weight of

evidence to conclude that the

construction activities caused the

exceedances on the exceedance days,

and that the exceedances would not

have occurred but for the construction

activity. The proximity of the

construction activities to the monitor

and the wind direction recorded at the

monitor support this conclusion.

Because EPA believes that the

provisions of the Exceptional Events

Rule have been satisfied, EPA is

proposing to concur with the SRR

Tribe's flags indicating that these

exceedances were due to exceptional

events, and to exclude the data from

consideration in determining whether

the SJV has attained the PM-IO

standard.

In proposing to concur with the SRR

Tribe's flags that construction activity at

SRR constituted exceptional events,

EPA is addressing only the particular

facts and circumstances presented by

the SRR monitoring operation. In

general, fugitive dust control measures

employed during construction activities

are helpful in reducing ambient PM-10

concentrations and avoiding

exceedances of the NAAQS. However,

in the specific circumstances of the SRR

during the days when exceedances were

recorded, we are not able to conclude

that the event was reasonably

controllable due to the very close

proximity of the monitor to the

construction activity, and the other

factors discussed above. Given this

singular constellation of factors, EPA is

proposing to concur with the Tribe's

flagging of the exceedances on

September 14, September 20 and

October 26, 2006 as caused by

exceptional events.

VII. Summary of Exceedances From

2004 Through 2006

The table below provides a summary

of exceedances relevant to today's

proposed rule that were recorded at

monitors located within the boundaries

of the SJV. The table indicates, whether

in determining attainment, EPA has

excluded or proposes to exclude the

exceedance, based on a finding that it

was due to an exceptional event. The

24-hour standard is attained when the

expected number of days per year with

levels above 150 gg/m 3 (averaged over a

three-year period) is less than or equal

to one. 40 CFR part 50, appendix K. As

shown in the table, all of the monitoring

locations are meeting the PM-10

standard.

TABLE SUMMARIZING PM-10 24-HOUR EXCEEDANCES IN THE SJV

[From 2004 through 2006]

Recorded (observed) - Number of estimated exceedances Average number

Monitor Operating schedule exceedances 2004-2006 of annual Included in Reason for excluding exceedances

Date Conc aftn. deter. exceedance 2004-2006

Corcoran Manual FRM ... 1 in 3 day ...................... 9/3/04 217 No ............... Exceptional Event ..... 0

9/22/06 215 No ................ Exceptional Event ...........................

Corcoran TEOM ............. Continuous ................... ..9/22/06 261 No ................ Exceptional Event .......... 0

10/25/06 304 No ................ Exceptional Event ..................

12/8/06 162 No ................ Exceptional Event ...........................

Bakersfield Golden Man- 1 in 6 day ...................... 9/22/06 157 No ................ Exceptional Event .......... 0

ual FRM.

Bakersfield Golden BAM Continuous .................... 11/22/05 156 Yes .............. N/A ................................. 0.67

11/23/05 180 Ypes .............. N/A ......................................

Bakersfield Golden Continuous .................... 9/22/06 157 No ............... Exceptional Event .......... 0

TEOM.

10/25/06 193 No ................ Exceptional Event ...........................

12/8/06 213 No ................ Exceptional Event ..........................

Tracy BAM ...................... Continuous .................... 9/22/06 161 Yes .............. N/A ................................ 0.33

Oildale Manual FRM ...... 1 in 6 day ........ ............. 9/22/06 162 No ................ Exceptional Event .......... 0

Santa Rosa Rancheria 1 in 6 day ...................... .9/14/06 190 No ................ Exceptional Event .......... 0

Manual FRM.

9/20/06 158 No ................ Exceptional Event ...........................

10/26/06 157 No ............... Exceptional Event ...........................

Sources:

EPA Air Quality System Database.

E-mail from Steven Shaw, SJVAPCD to Bob Pallarino, EPA Region 9, April 20, 2006..

E-mail from Steve Shaw, SJVAPCD to Bob Pallarino, EPA Region 9, October 12, 2006.

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VIII. Petitions for Reconsideration and

Withdrawal

A. Winds and Wildfires on September

22 and October 25, 2006

Earthjustice filed its 2006 Petition for

Reconsideration (PFR) before the State

provided its exceptional event

documentation for the September 22,

2006 exceedances to the public or EPA.

At that time CARB and the District had

simply informed EPA that, based on

preliminary analysis, they believed that

these exceedances were due to high'

wind and wildfire natural events.

Similarly, when Earthjustice filed its

2007 Petition for Withdrawal (PFW) and

the accompanying Jan Null declaration,

the State had not yet submitted the

complete documentation for the

September and October 2006

exceedances on which EPA is basing

this proposed rule. Therefore

Earthjustice's conclusion in the

petitions that the September 22, 2006

and October 25, 2006 exceedances do

not qualify as natural events does not

address the technical analysis of the

winds and wildfires as ultimately

submitted by the State and which EPA

has evaluated in section V. above. To -

the extent that Earthjustice's

assessments in the petitions of the

nature and effect of the winds and

wildfires are currently relevant, we

believe our evaluation in section V.

addresses the significant points raised

in them.

In addition, since EPA, as stated in

section V. above, agrees with the

petitioners that regional transport from

north of the SJV and the northern SJV

and wildfires were not the cause of the

exceedances on September 22 and

October 25, it is unnecessary for EPA to

further address the arguments raised by

petitioners with respect to these

theories.

B. Notice/Comment on September 22

and October 25, 2006 Exceedances

The gravamen of the 2006 petition,

which is reiterated in the Petition for

Withdrawal, is Earthjustice's claim that

EPA did not provide the public with an

opportunity to comment on the

September 22, 2006 exceedances and

thus should not have finalized the

attainment determination for the SJV.

PFR at 2-4. Petitioners also complained

that EPA did not require adequate

documentation that these exceedances

were caused by exceptional events. PFR

at 3-4.

Contrary to Earthjustice's assertions,

EPA did not abuse its discretion in

addressing the September 22, 2006

exceedances in its October 2006

determination of attainment. EPA noted

at the time that the exceedances were

based on preliminary data only:

"Because these data, which were

collected using manual reference

method samplers, are preliminary and

have not been quality assured, and

because EPA believes that they may

qualify as caused by natural events, and

thus be excluded from consideration in

an attainment determination, EPA is

proceeding to finalize its determination

that the area is in attainment." 71 FR

63642. Thus the data had not been

quality assured, and in addition EPA

was on notice that CARB and the

District intended to flag the data as due

to exceptional events and to request

EPA's concurrence on excluding the

data from consideration in an

attainment determination.

EPA went on to note that "[i]f, after

the dafa is quality assured, and after

further evaluating CARB's request with

respect to these data, EPA determines

that the data do not qualify for

exclusion under EPA's natural events

policy, and EPA further believes that if

included that they would establish that

the area is in violation of the NAAQS,

EPA will proceed with appropriate

rulemaking action to withdraw its

determination of attainment." Id. It was

thus clear that EPA's determination was

subject to revision based onsubsequent

quality assurance and evaluation of the

data, and EPA outlined its projected

procedure for dealing with the data once

they were quality assured and EPA had

an opportupity to evaluate the

documentation of the potential

exceptional events.

In this proposed rule, EPA is

following through with this procedure,

and is now providing for full notice and

an opportunity for comment, in the

context of a rulemaking, on whether

those exceedances qualify as caftsed by

exceptional events. EPA is also

providing notice and opportunity for

comment on additional claims that

exceedances were caused by exceptional

events on October 25, 2006, and

December 8, 2006, and at the Santa Rosa

Rancheria on September 14 and 20 and

October 26, 2006.

Contrary to Earthjustice's contention

in its Petition for Reconsideration and

Petition for Withdrawal, EPA did not

reverse the burden of proof required to

establish an exceptional event, or

relieve the State from the obligation to

document its claims. PFR at 4; PFW at

17. In the final determination, it is clear

that EPA did not conclusively concur in

excluding the data without requiring

appropriate documentation and a

showing from the State. Rather, EPA

deferred its determination on the impact

of the preliminary data until the data

could be quality assured and the State

would have an opportunity to meet its

burden of showing that an exceedance

qualified as caused by an exceptional

event. . Finally EPA notes that Earthjustice

alleges in its 2007 petition that the

Agency ignored in its final attainment

determination the October 25, 2006

exceedances as well as the September

22, 2006 exceedances. PFW at 2. This is

not the case. The exceedances in

October occurred eight days after EPA

promulgated its final determination of

attainment, on October 17, 2006. (The

notice was published on October 30, but

the determination had been signed and

disseminated to the public on October

17). Thus, EPA had no information on

these exceedances at the time of its final

action.

C. Wind Conditions in the Valley

With respect to the existence of high

winds in the Valley generally,

Earthjustice, in both petitions,

characterizes statements in the 2003

PM-10 Plan for the area as concluding

that wind erosion is not a significant

contributing factor in dust emissions

and as suggesting that winds with

enough velocity to cause erosion

disperse PM-tO concentrations and/or

transport PM-tO out of the Valley. PFR

at 4; PFW at 8. Earthjustice in its 2007

petitionalso cites a letter from the

District to EPA which states that "there

is no evidence of any significant linkage

between high winds and PM-10 federal

exceedance events [in the Valley]." Id.

at 8-9.

Earthjustice has taken the statements

in the 2003 Plan to attain the PM-10

standard out of context. Chapter 2 of the

Plan, quoted by Earthjustice, is a 12-

page general overview of the San

Joaquin Valley Air Basin, the purpose of

which is to describe normal or typical

meteorological conditions. It is not

intended to nor does it address unusual

winds such as those under

consideration here that may occur in the

Valley. Nevertheless, the District did'

determine that windblown dust is not a

significant problem in the SJV for the

purposes of attaining the PM-tO

standard. For example, the Plan states

that "[w]ind related PM-10 events are

rare but possible when conditions are

right" and that "PM-tO readings in the

SJVAB are most severe during the fall

and winter periods when wind speed

and direction are not conducive to

interregional transport." 2003 PM-10

Plan, ES-10, 2-6. The District also states

that "winds are effective in dispersing

PM-10 concentrations and/or

transporfing"PM-O but-of the Valley"

in explaihihg'whytthe spring and

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summer months, which are the windier

months of the year in the SJV, do not

yield higher PM-10 levels.

However, the fact that PM-10

pollution from windblown dust is not

generally a significant enough problem

in the SJV that it needs to be controlled

for the purposes of attaining the PM-10

standard, does not mean that

windblown dust cannot cause an

exceedance of the standard. In addition,

even if windblown dust were a

significant problem, there could be

individual situations where particular

conditions make it unreasonable to

expect the District and State to be able

to control sources in those

circumstances. For such situations, EPA

has issued the Exceptional Events Rule,

and previously its policies, which as

discussed above allows exceedances

caused by exceptional events to be

excluded from regulatory considerations

as appropriate if certain conditions are

met. Since there are many variables that

can cause exceptional event

exceedances, EPA believes the analyses

for such events should be reviewed on

a case by case basis 72 FR 13560. For

example, not all high wind days will

lead to exceedances and not all

exceedances monitored when high

winds are recorded are necessarily due

to those high winds. For the

exceedances discussed in today's

proposal, however, EPA believes the

State has made an adequate

demonstration that they were caused by

exceptional events and have met all of

the Exceptional Events Rule

requirements, and thus the data for

these particular events should be

excluded from regulatory consideration.

Earthjustice also cites a letter from the

District to EPA responding to a letter

from Charles Swanson to EPA

commenting on the 2003 PM-10 Plan.

April 15, 2004 letter from James Sweet,

SJVAPCD, to Doris Lo, EPA (Sweet

letter). Mr. Swanson disputes the

following passage from Table G-15 in

Appendix G entitled"BACM

Comparative Analysis for 'On-Field

Activities' concerning the BACM

justification discussion associated with

the "Other" category of the District's

proposed Agricultural Conservation

Management Practices:

The SJV does not have a windblown dust

problem to anywhere near the extent of the

other nonattainment areas. The SJV has some- of the lowest average wind speeds in the

country. No wind related exceedances have

been recorded in the basin during the last

three years. Wind speeds are highest during

the spring when PM-10 levels are at their

lowest. The majority of the fugitive dust

emissions are generated from earth disturbingactivities. Certain soil types and crops are

more prone to windblown dust problems.

The "Other" category will give the farmers

with the potential to experience wind blown

dust emissions the flexibility to address this

issue with a CMP.

March 18, 2004 letter from Charles

Swanson to Doris Lo, EPA (Swanson

letter) at 1.

In responding to Mr. Swanson, the

District stated in its April 15, 2004 letter

that "[the statements in the Plan

provide a general characterization of the

San Joaquin Valley (SJV) and, as with all

generalizations, are not without

exception." Sweet letter at 1.

Furthermore, while, as Earthjustice

points out, the District did also state

that an analysis of all wind events since

1990 did not establish a linkage to PM10 exceedances, the District also

enumerated technical limitations that

bear directly on this conclusion. For

example, the data used did not report

wind gusts and the 1 in 6 day sampling

for PM-10 will not capture all wind

events. Sweet letter at 7-8. Therefore,

Earthjustice's attempts to characterize

the statements in the Sweet letter

regarding windblown dust as absolute is

not warranted. Finally, the District also

asserts that:

Evaluation of past events indicates that

often the area with the highest PM-10 levels

is not where the wind is highest, but rather

where the wind begins to slow. To

understand the dynamics of this pattern we

need only review the mechanisms for

entrainment and deposition. When the wind

slows, it can no longer keep the larger PM10 particles aloft and they settle toward the

surface. The settling of particulates aloft * * * results in an increased concentration

in the deposition area.

Sweet letter at 2. This scenario is

precisely what occurred on September

22 and October 25, 2006 as discussed in

section V. above.

D. EPA's Natural Events Policy

1. BACM Implementation

In both petitions Earthjustice asserts

that EPA's 1996 Natural Events Policy

requires that the State demonstrate that

BACM were in place and that all

sources were in compliance in order for

EPA to concur on a high wind natural

event request. PFR at 5; PFW at 9.

Earthjustice contends that the State

cannot demonstrate that agricultural

sources were in compliance at the time

of the wind event since it is not clear

if any compliance inspections had been

conducted.

As discussed in sections IV. and V.,

EPA is evaluating the State's

exceptional event documentation under

EPA's Exceptional Event Rule and not

under its pre-existing policies. The Rule

does not require either a showing that

BACM was in place at the time of the

event or proof that sources were in

compliance. Rather, in the preamble to

the Rule EPA states that the State must

take reasonable and appropriate

measures under these circumstances. 72

FR at 13576-135 77. That said, -EPA has

approved the District's BACM

demonstration for all significant sources

of PM-10 in the Valley, including

agricultural sources, as meeting CAA

section 189(b)(1)(B). 69 FR at 30035; 71

FR 7683. Moreover-the State's

documentation for the September 22

and October 25, 2006 events includes

information on compliance inspections

throughout the SJV. See section V.

above.

2. District's Natural Events Action Plan

In its 2007 petition Earthjustice

claims that for the September 22, 2006

exceedances the District failed to meet

the requirements of its Natural Events

Action Plan for "[aicceptable

documentation for establishing an

extraordinary natural event * * *.

Specifically, Earthjustice contends that -

acceptable documentation for

establishing."an extraordinary natural

event" includes issuance by the national

Weather Service of a high wind or

blowing dust advisory, the occurrence

of strong winds aloft and surface wind

maps showing potential for high winds

to occur at the site. According to

Earthjustice no adequate documentation

of these factors was offered. PFW at 11.

Earthjustice's statements regarding the

requirements for documentation under

the District's "Natural Events Action

Plan for High Wind Events in the San

Joaquin Valley Air Basin," February 16,

2006 (NEAP) appear in the portion of its

2007 petition that addresses the causal

relationship between high winds and

the September 22, 2006 exceedances. Id..

Section 3 of the NEAP concerns the

documentation of high wind events and

lists specific sources of documentation

suggested by EPA: Filter analysis,

meteorological data, modeling and

receptor analysis, videos and/or

photographs, maps, news accounts and

BACM 97 requirements. Section 6 of the

NEAP concerns meteorological

forecasting criteria. This section states

that if certain enumerated criteria are

met, the District, in consultation with

CARB, will declare a NEAP episode.

The items that Earthjustice contends are

required to document an exceptional

event are among these criteria. Thus

Earthjustice has confused forecasting an

exceptional event with the

documentation of it. EPA believbs that

07 As noted above, BACM implementation is not

required under EPA's exceptional events rule.

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the State has adequately documented.

the September 22, 2006 exceedances as

being caused by all exceptional events

as discussed above in section V.A.

Finally we note again that EPA is

proceeding in this rulemaking under its

Exceptional Events Rule rather than the

1996 policy it replaces. In the preamble

to the Rule, EPA explained that

"following the promulgation of this

rule, States will no longer be required to

keep NEAPs in place that were not

approved as a part of a SIP for an area."

72 FR at 13576.

E. Harvest Activities

Earthjustice asserts in its 2006

petition that September is the peak

harvest season for cotton and almonds

and that EPA should investigate the

contribution of these activities to the

September 22 exceedances. PFR at 6. In

the 2007 petition Earthjustice states that

the end of October is generally when

two of the dustiest crop harvests, cotton

and almonds, take place and that these

activities caused the October 25

exceedances. PRW at 13-14. EPA

discusses the effect of anthropogenic

sources on the 2006 exceedances in

section V. above.

F. Exceedances at Corcoran and

Stockton in 2004, Bakersfield in 2005

and the Santa Rosa Rancheria in 2006

The 2007 petition raises issues

regarding several exceedances that have

already been addressed by the October

2006 attainment determination. These

exceedances occurred on September 3,

2004 at Corcoran and Stockton and on

November 22-23, 2005 at Bakersfield.

EPA's position on these exceedances is

found in the final rule at 71 FR at

63658-63661.

Regarding the September 3, 2004

exceedance, Earthjustice states that EPA

must now evaluate whether the Agency

can concur on the State's request to flag

the exceedance as a high wind event

and cannot continue to rely on the

argument that it is irrelevant because

"even if EPA had not concurred with

the exclusion of this data, the Corcoran

site would still attainthe 24-hour

NAAQS * * *." Earthjustice takes this

position because it believes there are

now other exceedances at Corcoran that

cannot be excluded and that the

September 3, 2004 exceedance will thus

be important in determining the SJV's

PM-10 attainment status. PFW at 9.

EPA disagrees with Earthjustice's

contention that there are now other

exceedances that cannot be excluded.

As discussed above, EPA believes the

exceedances on September 22, October

25 and December 8, 2006 are all due to

exceptional events and is proposing to

concur with the State's request to flag

these data as caused by high wind

events. Thus our conclusion that the

September 3, 2004 exceedance is not

significant for the attainmentdetermination is still valid.

Regarding the November 2005

exceedances at Bakersfield, EPA stated

in its determination of attainment that

"[elven if the Bakersfield-Golden State

Highway BAM and TEOM data are

considered together (and even if they

were quality-assured data not subject to

natural events), the exceedances

recorded at these-monitors would not

show that the area is in violation of the

standard." 71 FR at 63659. As discussed

above, EPA believes that the

exceedances at Bakersfield in 2006 were

due to exceptional events and is

proposing to concur with the State's

request to flag these data. Thus we still

believe that the 2005 Bakersfield-Golden

exceedances, when considered for

purposes of our 2006 attainment

determination, would not contribute to

or constitute a violation.

In the 2007 petition Earthjustice also

raises questions about exceedances

recorded at the Santa Rosa Rancheria on

September 14, 20 and October 26, 2006.

PFW at 15-16. EPA addresses these

exceedances in section VI. above.

IX. Statutory and Executive Order

Reviews

Under Executive Order 12866 (58 FR

51735, October 4, 1993), this proposed

action is not a "significant regulatory

action" and therefore is not subject to

review by the Office of Management and

Budget. For this reason, this action is

also not subject to Executive Order

13211, "Actions Concerning Regulations

That Significantly Affect Energy Supply,

Distribution, or Use" (66 FR 28355, May

22, 2001). This action merely proposes

a determination based on air quality

data and does not impose any additional

requirements. Accordingly, the

Administrator certifies that this

proposed rule will not have a significant

economic impact on a substantial

number of small entities under the

Regulatory Flexibility Act (5 U.S.C. 601

et seq.). Because this proposed rule does

not impose any additional enforceable

duty, it does not contain any unfunded

mandate or significantly or uniquely

affect small governments, as described

in the Unfunded Mandates Reform Act

of 1995 (Pub. L. 104-4).

Executive Order 13175 (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." Several Indian tribes

have reservations located within the

boundaries of the SJV. EPA is aware of

only one tribe in the SJV that operates

a PM-10 monitor, the Santa Rosa

Rancheria. EPA has consulted with

representatives of the Santa Rosa

Rancheria Tribe on the data recorded by

their monitor, and the flagging of the

data, and will continue to work with the

Tribe, as provided for in Executive

Order 13175. Accordingly, EPA has

addressed Executive Order 13175 to the

extent that it. applies to this action: This

proposed action also, does not have

Federalism implications because it does

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 (64 FR 43255,

August 10, 1999). This proposed action

merely makes a determination based on

air quality data and does not alter the

relationship or the distribution of power

and responsibilities established in the

CAA. Executive Order 12898 establishes

a Federal policy for incorporating

environmental justice into Federal

agency actions by directing agencies to

identify and address, as appropriate,

disproportionately high and adverse

human health or environmental effects

of their programs, policies, and

activities on minority and low-income

populations. Today's action involves

proposed determinations based on air

quality considerations and proposes to

affirm that the San Joaquin area has

attained the PM-10 NAAQS. It will not

have disproportionately high and

adverse effects on any communities in

the area, including minority and lowincome communities.

This proposed rule also is not subject

to Executive Order 13045 "Protection of

Children from Environmental Health

Risks and Safety Risks" (62 FR 19885,

April 23, 1997), because it is not

economically significant. The

requirements of section 12(d) of the

National Technology Transfer and

Advancement Act of 1995 (15 U.S.C.

272 note) do not apply. This proposed

rule does not impose an information

collection burden under the provisions

of the Paperwork Reduction Act of.1995

(44 U.S.C. 3501 et seq.).

List of Subjects

40 CFR Part 52

Environmental protection, Air

pollution control, Incorporation by

reference, Particulate matter, Reporting

and recordkeeping requirements.

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Federal Register/Vol. 72, No. 165/Monday, August 27, 2007/Proposed Rules

40 CFR Part 81

Environmental protection, Air

pollution control, National parks,

Wilderness areas.

Dated: August 15, 2007.

Wayne Nastri,

Regional Administrator, Region 9.

[FR Doc. E7-16693 Filed 8-24-07; 8:45 am]

BILLING CODE 6560-50-P

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