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

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 52and 81 [EPA-R09-OAR-2006-0583; FRL-8459-2]
Approval and Promulgation of Implementation Plans; Designation of Areas forAir Quality Planning, Purposes; State of California; PM-10; Affirmationof Determination of Attainmentforthe San JoaquinValley Nonattainment Area
AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule.

SUMMARY: Inafinal rule published in the Federal Register on October 30, 2006, EPA determined that the San Joaquin Valley nonattainment area (SJV

orthe Valley) in California attained the National Ambient Air Quality Standards (NAAQS) forparticulate matter with an aerodynamic diameter lessthan or equal
to anominal 10 micrometers (PM-1O). Since that final determination of attainment, the State has flagged several exceedances ofthe PM-10 standard in 2006 as being caused by exceptional events, i.e., high winds, andrequested thatthese 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 datafrom use in determining PM-10 attainment for the SJV. EPA is also proposing to exclude fromuse in determining attainment for the SJV exceedances recorded at a monitor located at the Santa Rosa Rancheria, tribal lands within the boundaries ofthe 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 duringthat time forpurposes of comparison to the NAAQS; and the exceedances were caused by an exceptional.event. EPA is proposing to

concur withthe Santa Rosa Rancheria Tribe'srequest 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 thePM-10 standard based onEPA's evaluation ofquality-assured data through December .2006.In addition to providing the public,with an opportunity to comment onEPA's evaluation and proposed concurrence

on flagged exceedances that occurred through the end ofcalendar year 2006, EPA is in this proposed rule addressing issuesraised in petitions for reconsideration and withdrawal of EPA's 2006 determination ofattainment, filed by Earthjustice on behalfofthe Sierra Club, Latino Issues Forum and others. DATES: Written comments mustbe received on or before September 26,' 2007. ADDRESSES: Submit comments, identified by docket number EPA-R09- OAR-2006-0583, by one ofthe 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 willbe included inthe public docket without change andmay 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 orotherwise protected should be clearly identified as such and should notbe submitted through the www.regulations.govor e-mail. www.regulations.govis an anonymous

access system,and EPA will not know your identity or contact information unless you provide it inthe body of your comment. Ifyou send e-mail directly to EPA, your e-mail address will be automatically captured and included as part ofthe public comment. IfEPA cannot readyour 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.govand 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 maybe 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: DorisLo, 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 ofContents I.Background H1. EPA's Proposed Actions III. Summary ofLitigation and Administrative Proceedings IV.EPA's Exceptional Events Rule V. EPA's Evaluation ofFlagged 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 ofSeptember 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 ofExceedances 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, 2006Exceedances C. Wind Conditions in theValley 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 andExecutive Order Reviews

I. Background
On October 17, 2006, EPA finalized its determination thatthe SJV attained the NAAQS for PM-IO, and on October 30, 2006, EPA published this determination inthe Federal Register. 71 FR 63642. This determination was based upon monitored air quality data for the PM-10 NAAQS 1during the
years 2003-2005 and all available quality-assured data throughJuly 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 ofattainment, EPA learned ofpreliminary dataindicating thatexceedances had occurred on

IEPA's final determination ofattainment 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 ofattainment, EPA has them as caused by natural events and to indicated that once quality-assured data obtained information regarding thePMwequest that EPA concur with these were available EPA would review those 10 exceedances summarized inTable 1, flags. EPA stated that because the data data andconsider whether the which were recorded at various

were preliminary and because they may .determination ofattainment should be monitors within the boundaries ofthe 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)

September 22, 2006

................................... C

orcoran (FRI, FEM)

.................................................................................................. 215, 261 Bakersfield-Golden (FRM

, FEM)

................................................................................... 157, 170 Oildale (FRM )

................................................................................................................ 162 October 25, 2006

....................................... Corcoran (FEM )

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

..................................................................... 193 D

ecember 8, 2006

..................................... : C orcoran (FEM )

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

..................................................................... 213 September 14, 2006

................................... Santa Rosa Rancheria (FRM)

... ;

. ...................................................................... 190 September 20, 2006

................................... Santa Rosa Rancheria (FRM)

.:

. ................................................................... 158 October 26, 2006

....................................... Santa Rosa Rancheria (FRM )

....................................................................................... 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 onJuly 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 ofthese exceedances qualify as natural
events and that the data should thus be excluded from consideration in the attainment determination.

OnJuly 9, 2007, EPA met with a representative ofthe Santa RosaRancheria EPA to discuss exceedances recorded on September 14, September 20 and October 26, 2006. The Tribe has flagged these exceedances asbeing caused by an exceptional event related
to construction activities and EPA has compiled documentation to support that claim.

II. EPA's Proposed Actions

Inthis proposed rule, EPA is proposing to concur with the State's request to flag exceedances ofthe PM10 standard within the SJV on

20nce airquality data have been submitted to EPA, it ispossible to "flag" specific values for various purposes. "Data flagging" refers to the act ofmaking anotation ina designated field ofan electronic datarecord. The principal purpose ofthe data flagging system inthe Air Quality System (AQS) database isto identifythose airquality September 22, October 25 and December 8, 2006 as being caused by exceptional events, Le., highwinds, 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 invery close proximity to construction activities and, as such, the monitor was notproperly sited during that time for purposes of comparison to the NAAQS; and (2)the exceedances were causedby

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 aresult, 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 willpublish 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 iswarranted. These include, but arenot limitedto, those measurements that are influenced by exceptional events. See 71 FR 12592, 12598 (March 10, 2006).

3 Afederalreference 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 ofthe monitor siting. EPA is not taking
comment in these proposed actions on any issues that were the subject ofthe 2006 attainment determination rulemaking except to the extent that they affect EPA's abilityto determine that the SJV continued to attain the PM10 standard through 2006.

In thisproposed rule we are also addressing relevant issues raised inthe petition for reconsideration and petition
to withdraw the determination of attainment filed bythe 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 ofthese 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 ofthe NAAQS, EPA would proceed with appropriate rulemaking action to withdraw its determination ofattainment. 71 FR 63642. Both EPA's natural/exceptional
events policies and its exceptional
events rule anticipate that the Agency willconcur or nonconcur on a state's request to exclude data by letterrather than rulemaking.

follows the procedures detailed inthe appendices to 40CFR part 50. A federal equivalent method (FEM)isan air sampling collection and analysis method which does not follow thereference procedures in40 CFRpart 50, but hasbeen certified and designated by the EPAas obtaining "equivalent" results. 

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Generally we would initiate rulemaking following an attainment determination for an area only ifwe had preliminarily concluded that a withdrawal ofthat determination would be appropriate. That is not the case here. However, in this instanceboth 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 oftheissues raised by thepetitions pendingbefore the Agency and discussed below, we are proposing to concur with the State's and Tribe'srequested flags and affirm our 2006 attainment determination via notice and comment rulemaking. Because we generally make determinations ofattainment on a calendar year basis, ourproposed rule addresses quality assured exceedances from September 14 through December 31, 2006. Moreover thepetitions address exceedances within this timeframe.

11. Summary ofLitigation and Administrative Proceedings

Earthjustice filedthree petitions related toEPA's determination of attainmeht for the SJV. On.December 27, 2006, Earthjustice, on behalf ofLatino Is~ues Forum, Medical Advocates for Healthy Air and Sierra Club, filed in the U.S. Court ofAppeals for the 9th Circuit

a petition for review ofEPA's October 2006 determination under the Clean Air Actthat the SJV has attained the PM10 standard. LatinoIssuesForumv. 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 otherthings, that EPA improperly ignored September 22, 2006 PM-10 exceedances in the SJV thatwere not subject to public notice and commerit. Finally, on March 21, 2007, Earthjustice'filed a petitionfor withdrawal of our attainment determination. In this petition, Earthjustice alleges thatthe attainment determination mustbe 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 ofthese administrative petitions in this proposedrule.

IV. EPA's Exceptional Events Rule

On March 22, 2007, EPA issued a finalrule governing the review and handling ofairquality data influenced by exceptional events. 72 FR 13560. The rule became effective on May 21, 2007 and implements section 319 ofthe CAA, as amended by section 6013 ofthe 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 datarelated to the

ozone and particulate matter NAAQS where states petition EPA to exclude data that are affected byexceptional
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 airquality monitor only in order to gather data for informational purposes but does not implement otherprograms such as mitigating the effects ofexceptional events, itis EPA's responsibility to

ensure that any exclusion or discounting ofdata in Indian country

areas comports with the rule's procedures and requirements. EPA intends to work with tribes on the implementation ofthe rule. 72 FR at 13563.

In 1986 and 1996 EPA issued guidance to address the use ofdata influenced by exceptional and natural
events: "Guidance on the Identification and Use ofAir 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 ofa 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 priorto the effective date ofthe rule whether an exceptional event hadoccurred after astate had flagged data and submitted a demonstration in

atimely manner to show that such data reflected NAAQS exceedances thatwere caused by an exceptional event. In these circumstances, EPA believes thatin the interests of equity and administrative efficiency, a state seeking to exclude data affected by exceptional events should, for a limited period oftime, be able to choose to comply with either the provisions ofthe rule or those ofthe guidance documents for a limited period oftime. This approach would have some advantages, such as allowing the stateto avoid duplicating its demonstration process and completing the decisionmaking process already underway. EPAbelieves that itis reasonable touse 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 notrelevant here, is defined

as one "that affects airquality, is not reasonably controllable or preventable, is an event caused byhuman activity that is unlikely to recur at a particular location ora natural event, and is determined by the Administrator in accordance with 40 CFR 50.14 ['treatment ofair qualitymonitoring data influenced by exceptional events']
tobe 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 ofdata and submission ofthe requisite demonstrations to EPA. 72 FR at 13571. In short, a state mustnotify EPA ofits intentto exclude measured exceedances ofa NAAQS asbeing due to an exceptional eventby "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 ofthe event,by July 1st of the calendar year following the year inwhich 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 isrequesting its exclusion must, after notice and opportunity for public comment, submita demonstration thatto EPA's satisfaction shows that the flagged event caused a specific concentration in excess ofthe .NAAQS atthe particular location to justify data exclusion. This demonstration mustbe submitted to EPA within 3 years ofthe calendar quarterfollowing the event, but no later than 12 months prior to an EPA regulatory decision. A statemust submit the public comments itreceived 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 ofnatural events, including high wind events (i.e., those that affect ambient particulate matter concentrations through the

. raising ofdust or through there-entrainment of material that has been deposited). See 72 FR at 13565-13566 and 13576-13577. EPA's interpretation ofthe rule with respect to high winds is addressed in section V.below. 

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Inthe preamble to the final rule, EPA explained that it will generally review the state's demonstration and provide a

concurrence ornonconcurrence on the flag in the AQS database within 60 days ofthe state's complete submission. EPA expects that, inmost 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 ofthe additional time required. 72 FR at 13571. Upon its concurrence on a flag, EPA Will exclude the data from use in determinations ofNAAQS exceedances and violations. 40 CFR 50.14(b),

Therequirements for the demonstration to justify data exclusion that the state must submit, in this instance, to EPA are setforth at 40 CFR 50.14(a), (b)(1),and (c)(3)(iii). In order to be considered for exclusion, the state must showthat 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 ofnormal historical fluctuations including background and there would have been no exceedance "but for" the event.40 CFR 50.14(c)(iii)(A)-(D).

One ofthe 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 ofnormal 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). Airquality impact and -causalconnection may be shown through a number ofmethods including modeling and speciation analysis. EPA will evaluate whether an event affected air quality and caused a particular concentration usingthe weight of available evidence and considering the historical frequency ofsuch measured concentrations. States must compare contemporary concentrations with distribution ofhistorical values and these may bepresented ona 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 nothave occurred "but for" the influence ofexceptional 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. Inthis 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 atthe 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 ofdocumentation inthe rule because the facts and circumstances could vary depending on, among others, meteorology, and geography. Instead, EPA illustrated through examples the kind ofinformation that states could consider in meeting the demonstration requirements ofthe 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 toexclude 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 ofthe NAAQS.

V. EPA's Evaluation ofFlagged Exceedances

The State andTribe have not specifically requested that EPA evaluate the September 14 through December 31, 2006 exceedances (whichoccurred before the effective date ofthe 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 underthe 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 ofthese requirements and criteria separately. For each ofthe exceedances being discussed intoday's proposal, EPA bases.its evaluation on the procedural requirements and technical criteria and mitigatibn requirements ofthe 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 aclear 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 promptpublic notification ofexceedance events. * Provide for public education on how to minimize exposure. * Provide for the implementation of appropriate measures to protect the public.

A. September22,2006Exceedancesat Corcoran, Bakersfield,andOildale
The 24-hour PM-10 NAAQS was exceeded at three monitoring locations

on September 22, 2006: The Corcoran monitoring siterecorded concentrations of 215 gg/m 3 and 261 gg/m 3 with a FRM sampler and a FEM automated continuous analyzer, 6respectively; the

5 Section 50.1(j) provides the regulatory definition ofan exceptional event. "Exceptional event" means

an event that affects air quality, is notreasonably controllable orpreventable, 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 CFR50.14 to be an exceptional event. It does not include stagnation ofair masses or meteorological inversions, ameteorological event involving high temperatures orlack of precipitation, or air pollution relating to source noncompliance.

6The FEM monitor currently operated atthe
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 3with 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 ofPM-10 contributed to exceedances of the 24-hour PM-10 NAAQS on this day: Wind-entrained dust from sources inthe central and southern SJV, which is identified as the primary source ofPM10;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 SJVcaused the exceedances at the three monitoring locations on September 22, 2006.

We donot 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 thetechnical criteria established in the Exceptional Events Rule, EPA findsthat 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 ofthe fires cited inthe documentation was within the boundaries ofthe SJV. Further, an independent review ofPM-2.5 speciation data collected at Bakersfield and Fresno on the days preceding and after September 22 shows nounusual concentrations ofcarbon. See http:// www.epa.gov/cgi-bin/htmSQL/ nxplorer/queryspehsql.Ifthe fires had had a significant effect on PM-IO concentrations, there would have been evidence ofincreased carbon (oneofthe 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 ofCalifornia. The anecdotal evidence consists ofnewspaper reports of reduced visibility due to smoke and the odor ofwood 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 forSeptember 22, Z006)

at 10. Station.8 EPA finds that the documentation lacks data linking the fires to the concentrations given the distance ofthe fires and the lack of corroborating speciation data and satellite photographs ofthe 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, EPAbelieves that the State's documentation thatregional

sources ofentrained 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 thenorthern SJV. EPA bases this conclusion on its review of the documentation which indicates that while there were high hourly averaged winds and gusts inthe northern central valley ofCalifornia, 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 tocontribute to an exceedance ofthe 24-hour PM-10 NAAQS.

Because EPA does not agree with the State's conclusions with respect to regional transport ofPM-10 from the northern SJV and with respect to wildfires, in thefollowing discussion regarding the September 22, 2006 exceedances we refer only to the State's conclusionthat 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'sAQS Database

All ofthe September 22, 2006 exceedances were flagged inEPA's AQS database as ofJuly 2007.

b. Public Had an Opportunity To Review and Comment on the State's Documentation

In February 2007, the SJVAir Pollution Control District (SJVAPCD or District} notified the public inlocal newspapers and on its Web site ofthe availability ofthe 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 theFebruary 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 onits 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 toEPA onApril 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

Inthis 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) oftheRule?

The State needs to show thatthe September 22, 2006 event, windentrained dust from sources in the central and southern SJV, affected air quality inthe Corcoran and Bakersfield
areas, 9 was not reasonably controllable

or preventable, was a natural event, and is determined byEPA through the process established in the Rule to be an exceptional event. We believe the State has supported its claims thatwinddriven dust from sources ofPM-10 in the central and southern SJV was the

cause ofthe September 22, 2006 exceedances, as discussed in detail below.

9The Bakersfield-Golden State Highway and Oildale monitors areapproximately 3.5 miles apart. For the purposes ofthis discussion, the analysis for the Bakersfield-Golden State Highway and Oildale monitorsis the same. 

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i-

Affected AirQuality

For an event toqualify as an exceptional event, the state must show that the event affected air quality. This criterion can be metby establishing that the event is associated with a measured exceedance in excess ofnormal historical fluctuations, including background, and there is a causal connection between the event and the exceedance. The demonstration ofa 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 Stateprovides documentation thatthe measured exceedances on September 22, 2006

were in excess ofnormal 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 ofthe clear causal relationship between,the event and the exceedances onthis day is discussed in greater detail in subsection b. below.

ii. Not Reasonably Controllable or Preventable

Section 50.1(j) ofthe Exceptional Events Rule requires that for an event to qualify as an exceptional event, whether natural 6ranthropogenic, 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 (theDistrict'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 ofPM-10 inthe SJV as meeting CAA section 189(b)(1)(B). 1 1

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 dustbeing raised byunusually 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. Inthe preamble EPA also explains that "[sitates mustprovide appropriate doeumentation to substantiate why the level ofwind 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.' 2We discuss the fugitive dust control measures in place inthe SJVon September 22 above.

With respect to the wind speed,EPA

concurs with the State's demonstration -thatthe 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 ofapproximately 40 mph. According tothe State, the Department ofWater Resources' extreme annual wind statistics indicate that the

mean annual peak gust forLemoore is 42 mph. 14 Thus wind gusts observed at Lemoore wereunusually highbecause they are close tothe typical highest annual value of42 mph. The State also provides documentation that shows that winds ofapproximately 18 mph will entrain and transport dust.1 5Winds 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 atthat wind speed

was transported towards Corcoran. Winds at Corcoran were not as iritense during thepeak hours at Lemoore. Table

12NED 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 ofField Program Measurements, Final Report Contract 2002-O6PM Technical &Business Systems, Inc., November 9, 2004 (Bush Report). 3 ofthe 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 fromthe 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. Webelieve that the State has met theprocedural requirements oftherule including flagging ofthe data, submission of demonstration, evidence ofthe public opportunity toreview and comment on the demonstration and mitigation requirements al discussed in section V.A.1. and 3. ofthis proposed rule. We further believe thatthe State has also met thetechnical 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 inthe 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 thePM-IO, an area northwest of Corcoran around the area ofLemoore. The State provides a convincing demonstration showing that the winds in the area ofthe central SJV

were of sufficient speeds toerode soils and entrain dust and that the wind direction moved thePM-10 southeast towards Corcoran and further to the Bakersfield area.-

Meteorological measurements in Lemoore show that this area hadthe highest hourly averaged winds in the SJV thatday, peaking at 10 a.m. with a speed of29 mph from the NNW and gusts atthe same time reaching 37

16NED Addendum for September 22, 2006 at 11, Table 3.

17Generally EPA concurs ornonconcurs by letter with requests to flag data as caused by exceptional
events. See ourexplanation in section I. above regarding why we are proceeding by arulemaking here. 

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mph.18 Lemoore is approximately 25 miles northwest ofCorcoran. Meteorological measurements were also obtained from a site at Kettleman Hills, which showed apeak hourly wind at 11

am of20 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. 2 0 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 of17.8 mph to support its conclusion that thesewind speeds

were sufficient to erode soils and entrain dustinto 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 Districtreceived complaints about dust emissions inLeinoore. 22This was at the time ofpeak winds in Lemoore. The District followed up on the complaints butdid not issue notices ofviolation. The State indicates thatthere were PM10 generating activities inthe area of Lemoore onthe morning ofSeptember 22, 2006 but thatthese activities were typical for the area and subject tothe District's fugitive dust regulations.23

The State shows a clear relationship between the wind speeds at Lemoore and Kettleman Hills andincreased concentrations at the Corcoran monitoring site. The documentation clearly shows that as hourly average wind speeds increased atthe three meteorological sites, hourly concentrations at Corcoran also increased. The peak hourly concentrations atCorcoran 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 of15 mph. While these wind speeds

were nothigh enough to erode and entrain soil,based on the wind speed threshold referenced above, they were sufficient to keep the coarse particles suspended inthe atmosphere. The

18

NED for September 22, 2006 at 11, Table 3.
-led"
20

fd. 21Id. at 13; Bush Report. 22NED for September 22, 2006 at 33, Table 15.
23Id. at 5 and 32-33.

24Id.at 11, Table 3. windswere also consistently from the northwest, which demonstrates that the

coarse particles which impacted Corcoran originated inthe areas northwest ofthe monitor, e.g. Lemoore where the winds were unusually high.

Using the threshold wind speed in the 2002 CRPAQS study, the State shows thatmost ofthe PM-10was generated upwind ofthe 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 dustfrom 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 ofPM-10 from Corcoran to the Bakersfield and Oildale monitors. The Bakersfield area monitors began to record hourly c6ncentrations in excess ofthe level ofthe 24-hour PM-la NAAQS two hours after the peak Corcoran hourly PM-10concentration, with the Bakersfield hourly PM-10 concentrations peaking five hours after the Corcoran peak hourly PM-10 concentration. Inorder 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 themaximum amount ofPM-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 ofPM-10 inthe Bakersfield area was lower than in Corcoran, but still significant enough to exceed theNAAQS. The lower PM-10 concentrations atBakersfield are likely due tothe dispersion ofthe dust plume and possibly deposition ofaportion of the dust particles along the path from the Corcoran area toBakersfield.

The State's demonstration for September 22, 2006 includes information onwind speed and direction 28that shows the correlation between the hourly wind speeds at meteorological sites inAlpaugh and Bakersfield-Meadows Airfield and the

25Id.at 13; Bush Report.

26

NED Addendum for September 22, 2006 at 7.
27Id.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 theresults of

a basic meteorological model known as Hybrid Single-Particle Lagrangian Integrated Trajectory.model (HYSPLIT).30 Itis important to note that while this modeling is not meant to quantify the particle concentration recorded in the Bakersfield area, it does offer support ofthe State's demonstration that the winds on September 22, 2006 were ofthe appropriate intensity and direction to

move a plume ofdust from the central SJV to the Bakersfield area.

c. Did the State demonstrate that the
event is associated with measured concentration in excess ofnormal historical fluctuations including background?

ForEPA toconcur with a state's claim that an exceptional event caused an exceedance, one ofthe requirements that the state mustmeet is to showthat the event is associated with concentrations that are beyondthe 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 ofthe concentrations recorded on that date. Section 4 ofthe Addendum includes Figure A-5 that
compares the peak 24-hour PM-10 concentrations recorded at Corcoran, Bakersfield and Oildale during the month ofSeptember 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 andhas recorded only four exceedances ofthe 24-hour PM-10 NAAQS. 33 A further analysis shows that, with the exception ofa flagged natural event in 2004, 24-hour

29The Oildale monitoring site does not record hourly PM-10 concentrations but usesa 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 anda continuous PM-la analyzer to provide hourly concentrations. Since the Bakersfield-Golden State Highway site and the Oildale siteare relatively close to each other (see footnote 9 above), we believe itis appropriate to ue the BakersfieldGolden State Highway continuous analyzer to characterize the temporal distribution ofhourly contentrations atboth sites.

30

NED Addendum for September 22, 2006 at 10. 31

NED Addendumfor September 22, 2006 at 14.
32From September 1, 2000 to March 22, 2001 the Corcoran monitor operated ona once-in-every-sixdays schedule.

33PM-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 ofSeptember for a seven year period, i.e, when we look atthe 59 samples collected during the September for the past seven years, a concentration greater than.100 gg/m 3

. occurred only five percent ofthe time.34 Exceedances ofthe NAAQS have occurred twice in September, which is less than four percent ofthe days sampled. Comparisons forthe month of September are more relevant than for the entire year because September has the highest concentration of dust but does not typically havethe highest PM10 concentrations, which occur in the winter season. Dust is typically less than 50% ofthe PM-10 during September. 35 During the winter season nitrates are the largest contributor, particularly in the southern part ofthe 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 outof33 days sampled recorded a level greater than 100 gg/m 3 (128 jig/m 3 on September 18, 2003), three percent ofthe time. 36

For Oildale, also operating a FRM on

a once-every-six-days schedule, 432 samples were collected from 2000to 2006. The PM-10 NAAQS was exceeded

once during this seven-year period. During the September nionths, only one day out of35 days sampled recorded a level greater than 100 g.g/m3 (111 jig/m 3

on September 14, 2006), less than three percent ofthe time.37

d. Did the State demonstrate that there wouldhave 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 mustinclude 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/m3on September 9, 2004, a 102 gig/m3

on September 24, 2004 and a 112pg/m 3 on September 23, 2006; See Id.

35"What are the Sources ofParticulate Matter", Presentation by Karen L.Magliano, California Air Resources Board, May 17, 2006 (Magliano Presentation).

36PM-10 Raw Data Report Bakersfield Golden 2000-2006, EPA AQS Database, July 30, 2007.

37PM-10 Raw Data Report Oildale 2000-2006, EPA AQS Database, July 26, 2007. estimate ofthe'estimated airquality impact from the event. 72 FRat 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 thatthere

were PM-10 generating activities, such

as agricultural and construction operations, in the area ofLemoore on the morning ofSeptember 22, 2006. These types ofactivities aretypical for the area. 3 6
The State next indicates that the greatest fraction ofPM-Ia at the Corcoran and Bakersfield sites on September 22 consisted ofparticles in the size fraction between PM-10 and PM-2.5. 39 This information indicates that geologic dust,as opposed to secondary PM orPM from combustion
sources, was theprimary contributor to the exceedances. The-fraction ofcoarse particles at Corcoran and Bakersfield on September 22 was 89% and 79% respectively. 4 0 These values mustbe compared to the typical geologic values for the Valley during September of approximately 30 Igg/m 3 which are less than 50% ofthe measured PM-10.4 1
Based-on the reported 89% value, the estimated geologic material forCorcoran

was approximately 190 to 230 .g/m3for September 22, 2006. The corresponding values for Bakersfield were 123-134.pg/
M 3

. Compared to the typical September value ofapproximately 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. Ifthe typical value of30 ig/m3 were used instead ofthehigh estimated geologic values derived from the PM-10-2.5 size fraction, the. resulting "adjusted" PM-1a values for Corcoran and Bakersfield wouldbe 50- 65 gg/m 3

.This result favorably
compares to the typical average September concentration ofless than 60 ig/m 3

. Allowing fer a PM-10 geologic value of60jg/m3

,which is twice the September norm, would onlyyield an "adjusted" concentration of 84 to 96 gg/

M 3

. All ofthese sets ofadjusted values

38NED for September 22, 2006 at 32-33. 391d.at 32, Figure 13. 40Id

41Magliano 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

.

Inaddition, the NED for September 22, 2006 includes Table 2 that liststhe 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. 43 Moreover, EPA has approved the District's BACM demonstration for all significant sources ofPM-la inthe SJV

as meeting CAA section 189(b)(1)(B).44 Furthermore, District staffperformed 46 inspections in the Valley on September 22 to ensure that regulated sources were complying withthe District's fugitive dust rules. 45The 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 inthe SJV.

Based onthe weight ofevidence 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 ofthe NAAQS.

The SJVAPCD adopted the "Natural Exvents Action Plan for High Wind Events in the SanJoaquin Valley Air

42NED for September 22, 2006 at 9.
43Id.at 32.

4469 FR 30006, 30035 (May 26, 2004); 71 FR 7683 (February 14, 2006).

45NEDfor September 22, 2006 at45-46. 

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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 priorto the
event and educating thepublic on how
to minimize exposure during high wind
events. The document also discusses

measures that are in place tohelp minimize exposure toelevated PM-10 levels. EPA believes that the detailed
processes and measures described inthe NEAP satisfy the mitigation requirements under 40 CFR 51.930.

a. Provide for Prompt Public Notification ofExceedance Events I Section 6 oftheNEAP 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 ofthe NEAP, which involves informing the local media, SJVAPCD staffand community groups.
b. Provide for Public Education on How To Minimize Exposure

Section 7 of theNEAP provides a list ofprecautions that can be taken to limit
exposure during a NEAP episode. The listincludes keeping windows shut, using air conditioners or heaters on the recycle/recirculating airmode, limiting
strenuous activity, and other precautions. Section 8 ofthe NEAP discusses the SJVAPCD's general'public outreach program on NEAP episodes which includes developing and providing a brochure and information about NEAP episodes bymeans of community events, health fairs, schools and civic engagements.

c. Provide for the Implementation of Appropriate Measures To Protect the Public
Section 10 ofthe NEAP discusses the SJVAPCD's measdres that reduce PM-10 emissions. These measures, including those approved by EPA as BACM forthe 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

EPAbelieves that the high winds in the area ofLemoore 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 ofevidence demonstration to show thatthese high winds generated and transported PM-10 from the area ofLemoore to Corcoran, causing an exceedance ofthe 24-hour PM-10 NAAQS. Winds between Corcoran and the Bakersfield area were sufficient to transportthe 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 highwinds inthe area ofLemoore, the Corcoran, Bakersfield and Oildale monitors would
nothave exceeded the 24-hour PM-10 NAAQS on September 22, 2006. Because EPA believes thatthe State has satisfied the provisions ofthe Exceptional Events Rule, EPAproposes to concur with the State's request to flag these exceedances asbeing dueto exceptional events and toexclude the data from consideration in determining whether the area has attained the PM10 standard.

B. October25, 2006Exceedancesat Corcoran andBakersfield

On October 25, 2006, the SJV recorded exceedances ofthe 24-hour PM-10 NAAQS at two sites, Corcoran and Bakersfield-Golden State Highway, using continuous PM-10 analyzers designated asFEM 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 tothese 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 dustfrom the central and southern SJV caused the exceedances at the twomonitoring locations on October 25, 2006.

1.Procedural Requirements

a. Data Are Flagged in EPA's AQS Database

The October 25, 2006 exceedances

were flagged inEPA's AQS database as ofJuly 2007.

46The District operates Tapered Element Oscillating Microbalance (TEOM) continuous automated analyzers at thesetwo sites in addition
to themanual high-volume Federal Reference Method (FRM) monitors. The FRMs operate at a less than everyday schedule, as allowed by EPA regulations,but neither ofthe 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. PublicHad 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 ofthe 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 byMarch 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," SanJoaquin Valley Unified Air Pollution ControlDistrict, April 23, 2007 (NEDfor October 25, 2006), and posted it on its Web site..

The SJVAPCD indicated thatno public comments were received during its public process.

c. TheDocumentation Was Submitted to Epa
TheNED 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 thisproposed rule, EPA is proposing to concur with the State's demonstration in the NED for October 25, 2006 that highwind-entrained dust caused the exceedances at thetwo monitoring sites.

2. Technical Criteria

a. Didthis 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 canbe metby establishing that the event is associated with a measured exceedance in excess ofnormal historical fluctuations, including background, and there is a causal connection between the event and the exceedance. The demonstration ofa clear causal relationship is necessary to establish that the event affected air quality and is also aseparate statutory requirement as discussed above.

In the NED for October 25, 2006, the Stateprovides 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 acausal connection between 

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the high winds recorded at Lemoore and the high concentrations at the monitors recorded atCorcoran andBakersfield. The State's demonstration ofthe clear causal relationship between the exceptional event and the exceedances

on this dayis 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 wasnot reasonably preventable or controllable. Here thisrequirement is metby demonstrating that despite reasonable and appropriate measures in place, the October 25, 2006 wind eventcaused the exceedances. During this event, there

were no other unusual dust-producing activities occurring in the SJVand 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 (theDistrict's general fugitive dust rules) andRule 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 ofPM-10 in the SJV as meeting CAA section 189(b)(1)(B). 48

iii. Was aNatural Event

In the preamble to the Exceptional Events Rule, EPA states that ambient particulate matter concentrations due to dust beingraised~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 atthe 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 forthe affected area during thetime of yearthat the event occurred." Id. at 13566.

The wind-entrained dust on October 25, 2006originated from anthropogenic

sources within California, i.e., from

47 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 thatthe wind speeds in the central SJV

were unusually high on October 25, 2006.50 Table 1 ofthe NED for October 25, 2006 lists the wind speeds inthe Hanford and Lemoore areas. The peak hourly averaged winds were in the range of29 to 31 mph at Lemoore,-with gusts reaching 40 mph.Peak hourly winds at Hanford were lower, in the
range of17 to 18 mph,but still in line with thethreshold wind speed of 17.8 mph. Hanford also recorded peak gusts of22 to 30 mph duringthe 10 a.m. to 12 noonperiod.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 ofthese intensities are relatively rare in the southwestern part ofthe SJV and occurless than 5% ofthe time, based on long-term monitoring records. 53

EPA concurs with the State's demonstration inthe NED for October 25, 2006 that the wind speeds occurring in the central SJV wereunusually high

on October 25, 2006. While the winds at Corcoran were not ashigh as those in Lemoore andHanford, as described in the State's documentation, the winds at Corcoran during the peakhourly PM-10 concentrations (8 a.m. to 11 a.m.) ranged from 10to 13 mph, which are unusual for this time ofyear inthat 'rea. These wind speeds, though notsufficient to erode dust, were sufficient to keep the entrained and transported dust from the high winds at Lemoore suspended for the period during whichthe exceedances occurred.

iv. Determined byEPA To Be an Exceptional Event

Finally, EPA must determine through the process established in the Exceptional Events Rule whether an exceptional eventoccurred. Webelieve that the State has metthe procedural requirements ofthe Rule including flagging ofthe data, submission of demonstration, evidence ofthe public opportunity to review and comment on the demonstration and mitigation requirements as discussed at section

4 9NED for October 25, 2006 at 29.

50 d. at sections 4 and 5.
51Id. at 11.

52 Id. at 22-23.

53Id. at 24. .V.B.1. and 3. ofthis proposed rule. We further believe that the State has also
met thetechnical criteria ofthe Rule as discussed at section V.B.2. ofthis 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 clearcausal 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 bythe Stateidentifies the area northwest ofCorcoran as the

source ofPM-10 during the October 25, 2006 event. Winds in the Lemoore area

were again in excess ofthe threshold wind speed for eroding and entrainingdust as discussed above. Table 1 ofthe NED for October 25, 2006 shows a clear correlation between the wind speeds in the Hanford andLemoore areas and the increased hourly concentrations at Corcoran. 54 In fact the peakwind speeds
at Lemoore and Hanford, which occurredbetween 10 a.m. and 12noon at Lemoore, coincide with the peak hourly concentrations at Corcoran. The peak hourly averaged winds were in the range of29 to 31 mph at Lemoore, with gusts reaching 40 mph.Peak hourly winds at Hanford were lower, in the
range of 17to 18 mph, but still in line with thethreshold 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 ofNED for October 25, 2006 compares the hourly wind speed and PM-10 concentration data from Corcoran with the hourly wind speed data from Lemoore ina graphical format.5 5 This graphic shows the almost perfect correlation between increased wind speeds atCorcoran and Lemoore with the increased PM-10 hourly concentrations at Corcoran.

The dust plumethat 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 theAlpaugh meteorological monitoring station,

54 NED for October 25, 2006 at11.

55 Id.at 12. 

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located between Corcoran and Bakersfield about 16 miles south southeast ofthe Corcoran monitoring site.56 Between the hours of9 a.m. and 4 p.m., wind speeds at Alpaugh averaged about 12 mph.5 s Since the meteorological data measured at

-Alpaugh is taken at 2meters Above

Ground Level (AGL), the average wind speed at 10 meters AGL is about 15 mph.5 8 EPA believes this average wind speed wouldhave been sufficient to keep the dustplume suspended, and that it facilitated the transport ofthe dust plume to the Bakersfield area..

The data inTable 1 ofthe NED for October 25, 2006 show the Bakersfield hourly PM-10 concentrations beginning
to exceed the level ofthe 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 ofPM-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 hourlyPM10 concentrations at Bakersfield-Golden State Highway slowly increasing through themorning hours ofOctober 25 until 8 a.m. Hourly concentrations increase at a higher rate between 8 a.m. and 1p.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

acorresponding sharp increase in hourly concentrations at BakersfieldGolden State Highway. Thisbehavior of the hourly concentrations supports the State's explanation that the dust plume thatfirst affected Corcoran traveled south over a period ofseveral hours and then impacted the Bakersfield monitor.

As with the September 22, 2006 event, the State includes forthe October 25, 2006 event the results ofabasic meteorological model known as the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT).6 0 It is important to note that while this modeling is notmeant to quantify the particle concentration, recorded inthe 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 ofdust fromthe central SJV to the Bakersfield area.

56 d. at 22-26. 57M.at 58.
s5id. at 24-26.

59M. at 14. 6Old.at 27. c. Didthe State demonstrate that the
event is associated withmeasured concentrations in excess ofnormal historical fluctuations including background?

For EPAto concur with a state's claim that an exceptional eventcaused an exceedance, one ofthe requirements thatthe state must meet is to show that the event is associated with concentrations that arebeyond 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 thanthe concentration recorded on October 25, 2006. An EPAreview ofcontinuous PM-IO data fromCorcoran 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, andwhile there were a number ofhigher concentrations on the days after October 25, notcounting the exceedances recorded onDecember 8, 2006, which are discussed further below in subsection d, thePM-10 concentrations at Corcoran and Bakersfield-Golden State Highway fell
to mostlyless than 100 again fromOctober 28 throughJune 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 themonth of October from 2000 to 2006 the maximum value recorded at Bakersfield was 116 gg/m 3 measured on October 16, 2001 andthe 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 andnot representative oftypical high concentrations recorded at these monitoring locations.

d. Did the State demonstrate that there would have beenno exceedance "but for" the event?

As discussed previously, to qualify as
anexceptional eventthe 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.

62Corcoran exceeded the 24-hourNAAQS on October 29, 2002 with a value of168 ptg/m3; PM10Raw 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 orviolation would not have occurred but forthe event. Such analyses do not require a precise estimate ofthe estimated air quality impact from the event. 72 FR at 13570.

To meetthis "but for" requirement the State firstshows that there were no unusual activities occurring in the affected areas in theValley that could have resulted in the exceedances, Specifically, based on information from District field staffand 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 staffobserved no unusual emissions other thanthose associated with" the wind event. The PM-10 generating activities were BACM-controlled sources that areusual for the area.63 District staffconducted 90 inspections throughout the SJV on October 25 to ensure sources were in compliance with District airpollution

- rules.64

The State notes in theNED for October 25, 2006 that thePM-2.5 to PM-10 ratio onthis day was very low, which indicates that mostly coarse PM

was present on the filter, supporting its claim thatthe concentrations recorded

onthis day were affected by a blowing dust event.65

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

we generally see particle concentrations that are mostlyin 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% ofthe totalPM-10. When we look at a comparison ofPM2.5 and PM-10 concentrations recorded

on October 25, 2006, we find that the PM-10-2.5 portion ofthetotal PM-10 represents about 93% ofthe total PM10 atCorcoran and 85 percent oftotal PM-10 atBakersfield. This high percentage ofPM-10-2.5, which is mostlyfugitive dust, is atypical forthis time ofyear and supports the State's demonstration that the PM-10 concentrations onthis day consisted of mostly coarse geologic material.

We can alsolook at the days immediately preceding and following

63 NED for October 25, 2006 at 7 and 29.
4Id.at35.

r5I. at 28. 6 6Magliano Presentation. 

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the exceedance day to see ifthe concentrations on October 25 were unusual. The PM-10 concentrations recorded on October 25 at Corcoran and Bakersfield were over three timeshigher than they were on October 24.67 PM-10 concentrations afterthe event decreased dramatically and by October 28, PM-10 concentrations atboth sites were below 100. See also the discussion ofthe 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 SJVon October 25, 2006, Regulation VIII and Rule 4550.68 Moreover, EPA has approved the District's BACM demonstration for all significant sources ofPM-10 in the SJVasmeeting CAA section 189(b)(1)(B). 69Section 9.2 ofthe NED for October 25, 2006 indicates that theDistrict staffperformed 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 ofevidence 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 forthe wind
event on thisday.
3. Mitigation Requirements

See section V.A.3. above.
Conclusion

EPA believes that the high winds in the area ofLemoore 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 ofevidence demonstration to showthat these high winds generated and transported PM-10 from the area ofLemoore to Corcoran, causing an exceedance ofthe 24-hour PM-IO NAAQS. Winds between Corcoran andthe Bakersfield area were sufficient to transport the dust that originated in the Lemoore area such that they caused the monitor atBakersfieldGolden State Highwayto also exceed the NAAQS. The documentation

67NED for October 25, 2006 at 16, Table 3. 68 1d. at 29.

696 9 FR at 30035; 71 FR 7683. 70NE for October 25, 2006 at 35. submitted bythe State demonstrates that but for the high winds in the area ofLemoore, the Corcoran and Bakersfield monitors would nothave exceeded the 24-hour PM-10 NAAQS

on October 25, 2006. Because EPA believes the State has satisfied the provisions ofthe Exceptional Events Rule, EPA proposes to concur with the State's request to flag these exceedances

as being dueto exceptional events and to exclude the data fromconsideration in determining whether the area has attained the PM-10 standard.

C.December8,2006Exceedancesat CorcoranandBakersfield

The SJVrecorded exceedances ofthe 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 162lig/m 3 at Corcoran and 213 gg/m 3 at Bakersfield-Golden StateHighway.

The State demonstrates that unusually high winds inthe 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 SJVon thisday were generally from the southwest, south and southeast, transporting dust northward and ultimately impacting the continuous PM-10 analyzer atCorcoran. Based on the evidence submitted, EPA agrees with the State's demonstration thathigh wind-entrained dust caused the exceedances atthe 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 ofJuly 2007.

b. Public had an opportunity to review and comment onthe State's documentation

In February 2007, the SJVAPCD notified thepublic inlocal newspapers and on its Web site ofthe availability of the document entitled "Natural Event Documentation, High Winds, Corcoran and Bakersfield, California, December 8, 2006," SJVUnified 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," SJVUnified Air Pollution Control District, May 23, 2007 and posted it on itsWeb site.

SJVAPCD thereafter made revisions per CARB's request and submitted to CARB the "Natural Event Documentation, Corcoran and Bakersfield, California, December 8, 2006," SJVUnified Air Pollution Control District, June 6, 2007 (NED for December 8, 2006) and posted iton its Web site.

The District indicated that no public comments were received duringthe public process.

c. The Documentation Was Submitted to EPA

The NED for December 8, 2006 was subsequently submitted by the State to EPA onJune 12, 2007 and is the document upon which EPA is basing its evaluation below.

d.EPA Concurs With the State's Demonstration

In this proposedrule, EPA is proposing to concur with the State's demonstration in theNED for December 8, 2006 thfat high wind-entrained dust caused the exceedances at thetwo monitoring locations on December 8, 2006.

2. Technical Criteria

a. Did this event satisfy the criteria in section 50.1(j) ofthe Rule?

As with the previous events discussed in this proposed rule,the State needs to show that this event, identified in the NED forDecember 8, 2006 as unusually high winds, affected airquality inthe Corcoran and Bakersfield areas, was not reasonably controllable or preventable,

was a natural event, and is determined byEPA to be an exceptional event.
i. Affected Air Quality

For an eventto qualify as an exceptional event, the state must show that the event affected airquality. This criterion can be met by establishing that the event is associated with a measured exceedance in excess ofnormal historical fluctuations, including background and there isa causal connection between the event and the exceedance. This demonstration ofa causal connection is necessary to establish thatthe event affected air quality and is also a separate statutory requirement as discussed above.

In theNED 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 windsrecorded in the Bakersfield and Southern SJV area and the high concentrations recorded at the Corcoran and Bakersfield monitors. The State's demonstration ofthe 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)oftheExceptional Events Rule requires that for anevent to qualify as an exceptional event, whether natural or anthropogenic, a state must showthat 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 inplace, including Regulation VIII (theDistrict's general fugitive dust rules) andRule 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 ofPM-10 in the SJV

asmeeting CAA section 189(b)(1)(B). 72

iii. Was aNatural Event

In the preamble to theExceptional Events Rule, EPA states that ambient particulate matter concentrations due to dust beingraised byunusually 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 tohave beenreasonably well-controlled at thetime that the
event occurred, orfrom 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 withthe event in question should be considered unusual forthe affected area during thetime of
yearthat the eventoccurred." Id. at 13566.

On December 8, 2006, the windentrained dust originated from anthropogenic sources within

71

NED forDecember 8, 2006 at25.

7269 FR at 30035; 71 FR 7683. California, i.e., from usual dust-

- generating activities such as agricultural and industrial operations. 73We discuss the fugitive dustcontrol measures in place inthe 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 onDecember 8, 2006. The State includes information

on theunusual nature ofthe windspeeds inthe SJV onDecember 8, 2006, stating that winds ofthese magnitudes

are rare, occurring less than 5% ofthe time. The NED forDecember 8, 2006 reports that during the blowing dust event, Bakersfield reported winds up to 25 mph with gusts up to 35mph. Farther north in the area ofKettleman Hills, located onthe west side ofthe San JoaquinValley, gusts up to 50 mph

were reported. Kettleman Hills also reported a twenty-two hourperiod with gusts of 20 mph or greater (from6 a.m.

on December 8, 2006 to 4 a.m. on December 9, 2006). Maricopa, located

on the southwest side ofthe San Joaquin Valley approximately 25 miles southwest ofBakersfield, reported a one-minute average wind speed of56 mph.74

iv. Determined by EPA To Be an Exceptional Eevent

Finally, EPA must determine through theprocess established in the Exceptional Events Rule whether an exceptional event occurred. Webelieve thatthe State has met the procedural requirements oftheRule including flagging of the data, submission of demonstration, evidence ofthe public opportunity to review and comment on the demonstration and mitigation requirements as discussed at section V.C.1. and 3. ofthisproposed rule. We further believe thatthe State has also
met the technicalrequirements ofthe 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

onDecember 8, 2006.

b. Does the State's documentation show

a clear causal connection between the exceedances andthe 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

73NED forDecember 8, 2006 at 25.
74Id. at 17. December 8, 2006 were erratic and generally from the east, south, and southwest.75Wind speeds at meteorological stations near Bakersfield recorded hourly average wind speeds in

excess of35 mph and wind gusts in

excess of50 mph..Winds at Bakersfield

on December 8 were from both the southwest and southeast during thetime whenpeak 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 1p.m. to 3 p.m. atboth the Corcoran and Bakersfield sites, with a second set ofhigh 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 fromthe southeast, supporting the State's argument thatthe dust plume moved fromthe southeast to northwest.76

Table 3 and Figure 2 ofthe NED for December 8, 2006 77 show the correlation ofwind speeds and increasing hourly concentrations ofPM10 recorded by the continuous PM-10 analyzers atCorcoran and Bakersfield.

Figure 7 ofthe NED for December 8, 2006 includes the results of abasic meteorological model known asHybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT).7 It is important to note that while this modeling is not meantto quantify the particle concentration recorded in the Bakersfield and Corcoran areas, it does offer support ofthe State's demonstration that the winds on December 8,.2006 were ofthe appropriate intensity and direction to

move a plume ofdust from the southeastern SJV tothe Bakersfield area and northward to Corcoran.

c.Didthe State demonstrate that the
event is associated with measured concentration in excess ofnormal historical fluctuations including background?

ForEPA toconcur with a state's claim that an exceptional event caused an exceedance, one ofthe requirements thatthe 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).

75Id.at11, Table 3. 76Id.at 56. 77Id. at 11-12. ': 78I

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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 ofthe NED forDecember 8, 2006 demonstrate therelative infrequency, over the last 10 years, ofthe concentrations recorded at Corcoran and Bakersfield on December 8, 2006. When we look at PM-10 FRM concentrations recorded atCorcoran in themonth ofDecember 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 of96 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 inDecember

was 159 recorded onDecember 30, 1998. Ofthe 42 December FRM sample days since 1997, 9 daysexceed 100. Again, even when we include the continuous daily data from 2006, the result remains 9 days exceeding 100 in the last 10years. 80

d. Didthe 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 havebeen

no exceedance "but for" the event. 40 CFR 50.14(c)(3)(iii)(D). Tomeet this "but for" requirement, the state must include analyses to demonstrate that an exceedance or violation wouldnot have occurred but for the event. Such analyses do notrequire aprecise estimate ofthe estimated air quality impact from the even. 72FR at 13570.

To meetthis "but for" requirement the State first shows that there were no unusual activities occurring in the affected areas in the Valley thatcould have resulted inthe exceedances. Specifically, based oninformation from District field staffand discussions with representatives ofagricultural and industrial operations in theValley, activities that generate anthropogenic PM-10were approximately constant in theValley immediately before, during and after the event. As on September 22 and October 25, 2006, activity levels in the SJV were typical forthe time ofyear

79PM-10 Raw DataReport Corcoran 1997-2006, EPA AQS Database,July 30. 2007.

BoPM-10 Raw DataReport 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 ofthe SJV.81

The State provides frequency distributions ofthe maximum PM-10 24-hour December concentrations for the past 10 years. These figures indicate that PM-10 concentrations at Corcoran and Bakersfield-Golden StateHighway rarely exceeded the level ofthe 24-hour PM-10 NAAQS. 82This fact is an indication that December 8, 2006 was unusual inthat the normal emission activity levels do not cause exceedances, based on historical data.

Examining the make-up ofPM-10 on this day using PM-2.5 data collected at the sites with a continuous PM-2.5 analyzer, we can seethat coarse particles, or PM-10-2.5, which are associated with windblown dust, represented 78% ofthe total PM-10

mass collected at Corcoran and 88% of the total PM-10 mass at Bakersfield. CARB studies indicate that at this time ofyear, fugitive dust generally contributes less than 20% ofthetotal PM-10mass. 83 The atypical contribution offugitive dust.tothe 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 fromthe days immediately preceding and after December 8, 2006.84 Twenty-four hour PM-10concentrations on December 4- 6 were lessthan 100gg/m3 atboth sites and werejust over 100 gg/m 3 on December 7. OnDecember 8, the concentration at Corcoran increased by

morethan 50%, exceeding the NAAQS with a level of 162 tg/m3, but then fell
to 32 9g/M 3 onDecember 9 and continued dropping for weeks after this
event. AtBakersfield, onDecember 8 therewas agreater than 100%increase

overtheDecember 7 concentration. Again, concentrations dropped dramatically onDecember 9 and remained low for weeks after.

Finally, as discussed above, there

werereasonable and appropriate

measuresin place to control PM-10in the SJVon December 8, 2006, RegulationVIII and Rule 4550. 85 Moreover, EPA has approved the District's BACM demonstration for all significant sources ofPM-10in the SJV

81

NED forDecember 8, 2006 at 25. 82Id.at 28-29, Figures8 and 9. 83Magliano Presentation.

84NEDfor December 8, 2006 atTable 1.
8sW.at25. " 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 inthe SJV.

Based on the weight ofevidence presented, EPA concludes that the State's documentation demonstrates that the exceedances at Corcoran and Bakersfield on December 8, 2006 would
nothave occurred but forthe 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 ofevidence demonstration to showthat thesehigh winds generated and transported PM-10 from the area ofBakersfield to Corcoran causing exceedances ofthe 24-hour PM10 NAAQS atthe Bakersfield and Corcoran monitors. The NED for December 8, 2006 submitted bythe State demonstrates that but for thehigh winds inthe southern SJV, the Corcoran and Bakersfield monitors would not have exceeded the 24-hour PM-10 NAAQS onDecember 8, 2006. Because EPAbelieves that the State has satisfied the provisions ofthe Exceptional Events Rule, EPAproposes 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 ofSeptember 14, September 20 and October 26,2006 

### Exceedances attheSantaRosa Rancheria

The 24-hourPM-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 157tig/m3

,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 onthe SRR, located on theroofofapumping station at the SRR's water treatment facility. ThePM10 sampler is ahigh volume size

8869 FR at30035; 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.

ThePM-10 sampler is located near the northeast corner on the roofofthe pumping station. The current land cover around the pump station ispaved parking. There are no obstructions of any kind andthere is unrestricted airflow 360 degrees around the sampler inlet.87

To the east ofthe monitor is apaved parking lot, beginning about 25 feet east ofthe monitor location and extending approximately 50 feet tothe east. Beyond the parking area are trailers and undeveloped land.To the north ofthe monitor is a larger parking lot, beginning about 100 feet north ofthe 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 theremaining physical plant facilities (tanks, pumps, etc.) and the area is paved. Further south and west are agricultural fields (currently alfalfa). Agricultural -fieldsalso lie to the north beyond the casino and parking lot (approximately 0.5 mile). To the east is the SRRresidential area.

PM-10 is measured once-in-every-six days by the SRREPA according tothe national sampling schedule. Sampling began onAugust 3, 2006 and continues
to thepresent time.

In 2006 there was a major construction project at the SRR, which involved construction ofa 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 ofthe SRREPA was to begin operation ofthe monitor and sampling only after completion ofthe parking lots and external portion ofthe '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 thatmany ofthe samples collected since PM-10 monitoring began

onAugust 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 ofthe 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 ofthe data between August 3 and November 25, 2006 submitted to the AQS database, hasbeen 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 thetime period the monitor was operating in such close proximity to the construction, the monitor shouldbe considered tohave been improperly sited under theprinciples 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 tothe monitor constitutes an exceptional eventthat caused the exceedances. EPAbelieves thatboth of these rationales, separately or together, supportEPA's proposal not toinclude the SRR monitor data recorded during the period ofparking lot construction in

our determination ofwhether the SJV has attained the PM-10 NAAQS.

A. Evaluation Under Principles Establishedin 40 CFRPart 58, AppendixE

40 CFR part 58 establishes criteria and requirements forambient air quality monitoring, and appendix E sets forth the probe and monitoring path siting criteria for ambient airquality 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 extentpossible." 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 datathey collect are tobe used for purposes ofcomparison tothe NAAQS. Itis not clear whether the monitor in Santa Rosa Rancheria is intended tobe designated a Special Purpose Monitor. Itis 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, EPAbelieves that it is not



### 88Site Visit Memorandum. 89AQS Raw Data Report, Santa Rosa Rancheria

PM-10 2006 to 2007. a reasonable monitoring practice to locate a PM-10 monitor,intended for purposes ofcomparison to theNAAQS,

so close to an obviously temporary dust
source, as was the case atthe SRR.

Section 3(a) ofappendix E, Spacing fromMinor Sources, addresses the siting ofmonitors, including PM-10 monitors. It states that close spacing between amonitor and a minor source may be proper ifthe purpose ofthat monitoring site isto investigate emissions from that source and other local sources. However, if, as is the case with the SRR monitor here, the site is tobe used to determine airquality over
a larger area, such as a neighborhood or city, it shouldnot be placed near local, minor sources, because the plume from the local minor source would inappropriately impact the air quality data collected atthe site. Itis plain that this occurred in the SRR situation, where the monitor, when itbegan 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 afterthe conclusion ofthe construction activity. As a consequence ofmonitoring while this construction

was still ongoing, the SRR Tribe was compelled to flag data for 12 ofthe 19 sampling days that occurred between August 3 and November 25, when the construction concluded. Thus more than 60% ofthe datacollected during thistime period was considered to be unusable forregulatory purposes.

The dramatic contrastbetween concentrations monitored while construction was ongoing and postconstruction concentrations also testifies to the impact thatthe improper siting had onthe monitored data. After construction ceased, average monitored PM-10 concentrations declined 50%. See discussion below in section VI.B.2.d. below. EPAbelieves that after the construction concluded themonitor
met the appropriate siting criteria. 9 0 EPA has concluded that underthe very unusual circumstances presented in the SRR, itwas not appropriate, according to the principles established in part 58 appendix E, to deploy anew PM-10 monitor, forpurposes of comparison to the NAAQS, so close to temporary construction activity, for the duration ofthat activity. EPAbelieves it wouldbe unreasonable forthe Agency

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to allow the data from such amonitor
to determine the attainment status ofth Siv.

Conclusion

EPA is proposing toconclude that th( exceedances in the SJV atthe SRR monitorthat 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 themonitor waE
not properly sited, under the principles established in part 58, appendix E.

Inproposing to find that,during the period ofconstruction, themonitor was not properly sited for the purpose of comparison tothe 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 ofmonitoring operation.s, and that monitoring was originally intended to begin only after the conclusion ofconstruction 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 SJVhas attained the PM-10 standard.

B.EvaluationUndertheExceptional EventsRule

In addition tothe rationale regarding the siting ofthemonitor, set forth abovt EPA proposes to concur with the SRR Tribe's flagging ofthe exceedances at the SRRbecause EPAbelieves thatthe construction activity constitutes an exceptional event under EPA's Exceptional Events Rule. Our application ofthe requirements ofthe Rule to the SRR exceedances is set fort below.

1.Procedural Requirements

a. DataAre Flagged-in EPA's AQS Database

The three exceedances were flagged by the SRR Tribe by the time the data

were submittedto theAQS database in 2006.

b. PublicHad 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 havebeen flagged asbeing caused by exceptional events. The Exceptional Events Rule recognizes thai .tribes may notbe in a position to

e address all ofthe requirements ofthe Rule and thus states that EPA will "* * * work with tribes on the implementation ofthis rule,which may inclde appropriate implementatioii by EPA ofprogram elements ensuring that
any exclusion * * * ofdata in Indian country with air quality affected by exceptional events comports with the procedures and requirements ofthis rule." 72 FR at 13563. EPA, through this proposed rule, is providing the public with an opportunity to review and
comment on the documentation ofthese exceptional events.

c. The Documentation Was Submitted to EPA

As discussed above, EPA is assisting the SRR Tribe bycompiling and evaluating the documentation ofthe exceedances which they have flagged as being caused byexceptional events.
d. EPA Concurs With the Tribe's Flagging andDemonstration

EPA isproposing to concur with the SRR Tribe's flagging ofthese exceedances as affected byexceptional
events. As discussed above, EPA is assisting the SRR Tribe by compiling and evaluating the documentation ofthe &xceedancesit has flagged as being caused by exceptional events, and by ensuring thatthe public has an opportunity, through this rulemaking, to review and comment uponit.

2. Technical Criteria

a. Did this event satisfy the criteria in section 50.1(j) oftheRule?
i. Affected Air Quality

For an event toqualify as an exceptional event, the state or tribe must show that the event affected air quality. Here, EPA, onbehalf ofthe SRR Tribe, needs to show that theevent, identified

as construction activity, affected air quality at the SRREPA PM-10 monitor. This criterion can be met byestablishing that the event is associated with a measured exceedance inexcess of normal historical fluctuations, including background, andthere is a causal connection between the event and the exceedance, This demonstration ofa causal connection isnecessary to establish thatthe event affected air quality, and itis also a separate statutory requirement as discussed above.

Because the SRREPA PM-10 monitor hasbeen in operation only since August 2006, itis not possible to compare the data from exceedance days tohistorical levels. In this case, however, we can look at data that havebeen collected since the construction and parking lot paving was completed to determine representative concentrations ofPM-10 in the absence of alarge, 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 ofthe 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) ofthe Exceptional Events Rule requires that for an event to qualify as an exceptional event, whether natural oranthropogenic, a state, tribe (or,in this case, EPA) must show that the event was notreasonably preventable or controllable.

EPA believes that it would not-ave beenreasonable to prevent the activity, i.e., paving ofparking lots that were needed for the SRR Tribe's facilities. Paving a parking lot (whichinvolves grading the ground, applying abase material such as gravel and applying asphalt) is a generally accepted form of control ofPM-10.91 To prevent the paving ofa parking lot would not only be unreasonable, but illogical.

Withrespect towhether the event was reasonably controllable, we note thatthe SRR Tribe does nothave 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 underthe CAA. * * *"92 "EPA recognizes Tribal Governments as sovereign entities with primary authority and responsibility for the reservation populace. Accordingly, EPA willwork directly with Tribal Governments as theindependent

91See, for example, SJV.Rule 8051 Open Areas (AdoptedNovember 15, 2001; Amended August 19, 2004) and Rule 8071 Unpaved Vehicle/Equipment Traffic Areas (AdoptedNovember 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 ofStates or other governmental units." 93

While paving itself is a control

measure, EPArecognizes that other control measures may bq reasonable during a paving process. For example, the SJVAPCD regulations require, among otherthings, that regulated construction sites apply-as appropriate
water or chemical/organic stabilizers or construct and maintain wind barriers.94

In the circumstances ofthe SRR, however, even ifthese types of

measures had been actively employed,

we cannot be certain that they would have prevented exceedances atthePM10 monitor.This is due in large partto the unusual circumstance presented here ofthe very close proximity ofthe construction activity to themonitor.As noted above, one ofthe parking lots was within 25 feet ofthemonitor, and the other was within 100 feet.

EPA's evaluation oftheparking lot construction activity's impact onthe monitor, andwhether it was reasonably controllable, during the activity, is informed by EPA's views onwhat constitutes acceptable monitor siting. As EPA has set forth in detailabove, EPA believes that, for the duration ofthe construction activity, the monitor was not properly sited for the purposes of determining attainment ofthe 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 ofPM10 mohitors, are instructive with respect to EPA's analysis ofthe exceedances under the Exceptional Events Rule. We
cannot conclude thatthe activity was reasonably controllable given that the exceedances were measured at a monitor thatEPA's rule provides should
not be operated at such a time and place, for the purposes of determining attainment. Thus, under .theparticular
set ofcircumstances presented here, for the purposes ofevaluating the "reasonably controllable" criterion of the-Exceptional Events Rule, we deem this criterion to have been satisfied.

iii. Was an Event Causedby Human Activity That is Unlikely toRecur at a Particular Location

In this case, the event was paving of parking lots in the vicinity ofthe PM10 monitor, and is a construction activity that is not expected to recur at that location.

9359 FR 43956 (August 25,1994).
94SJVRule 8021 Construction, Demolition, Excavation, Extraction, and OtherEarthmoving Activities (AdoptedNovember 15, 2001; Amended August 19, 2004). iv.Deterjnined byEPA To Be an Exceptional Event

Finally, EPA must determine through the process established inthe 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. Webelieve that by the initial flagging ofthe data, and through the vehicle ofthis proposed rulemaking we will demonstrate that the procedural requirements and technical criteria oftherule willhave 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 causalrelationship mustbe

-established between the measured exceedance andthe claimed exceptional
event. The information compiled by EPA shows aclear 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,thatthere was construction nearby. Copies ofthese 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 onthe three days that exceeded the NAAQS, winds were predominantly from thenorthwest to northeast.This would indicate that any dust-producing activity north and northeast ofthe monitorwould result in high concentrations of geologic dust being blown towards themonitor.

The meteorological data lend support to the environmental technician's
account ofthe events ofthat day.EPA also discussed these events with the SRR construction superintendent, Who agreed with the environmental technician's account ofthe construction activity. Aprivate consultant working for the SRREPA also stated that he had witnessed major earth-disturbing activities on these days.9 a Based on the meteorological data, eyewitness accounts, and an on-site inspection ofthe monitoring site location and its proximity to the parking lots, we believe thatthere was a clear causal connection between the construction activity andthe recorded PM-10 exceedances.

95Site VisitMemorandum. c. Can itbe demonstrated that the event is associated with ameasured concentration in excess ofnormal historical fluctuations including background?

ForEPA 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).

Ofthe 44 samples colleeted bythe SRREPA, nearly 80% ofthe samples (35 days) were less than 100 gg/m 3

.After completion ofthe paving projects in mid-November, 2006, average PM-10 concentrations dropped by more than 50%, from an average of 97jig/m3 to an average of45 gg/m3. 96This would indicate that the construction activity had an obvious effect on the concentrations recorded by the SRR monitor and thatthe datacollected during this construction period, including the exceedances recorded in September and October, 2006, were not representative oftypical postconstruction PM-10 concentrations at the location ofthe monitor.

d. Can itbe demonstrated that there wouldhave been no exceedance "but for" the event?

To qualify as an exceptional event, there mustbe 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 notrequire a precise estimate ofthe 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, theproximity ofthemonitor
tothe construction activity and the concomitant infeasibility ofcontrol

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 ofthepaving projects, we believe the weight of evidence shows that the exceedances would not have occurred but for the construction activity.

96SantaRosa Rancheria PM-10 24 hour average concentrations, Excel spreadsheet, BobPallarino. 

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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 protectpublic health from exceedances orviolations ofthe NAAQS. In the case ofthe SRR, EPA recognizes that tribesmay implement only portions of air quality programs and notbe in a position to address each ofthe procedures and requirements associated with excluding or discounting data. In the preamble to the Exceptional Events Rule, EPAcites an example oftribes that"* * * may operate amonitoring network for purposes ofgathering and identifying appropriate data,but may not implement relevant programs for the
purpose ofmitigating the effects of exceptional events. * * " 72 FR at 13563. That is the case with the SRR. Under these circumstances, as indicated in thepreamble to the Exceptional Events Rule, EPA intends to workwith the SRR on the implementation ofthe 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 thatthe exceedances would not have occurred butfor the construction activity.The proximity ofthe construction activities to the monitor and the wind direction recorded at the monitor support this conclusion. Because EPA believes that the provisions ofthe Exceptional Events Rule have been satisfied, EPA is proposing to concur with the SRR Tribe's flags indicating thatthese exceedances were due to exceptional events, and to exclude the data from consideration in determining whether the SJVhas attained the PM-IO standard.

In proposing to concur with the SRR Tribe's flags that construction activity at SRRconstituted exceptional events, EPA is addressing only theparticular facts andcircumstances presented by the SRR monitoring operation. In general, fugitive dust control measures employed during construction activities

are helpful inreducing ambient PM-10 concentrations and avoiding exceedances ofthe NAAQS. However, in the specific circumstances ofthe 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 ofthe monitor to the construction activity, and the other factors discussed above. Given this singular constellation offactors, EPA is proposing to concur with the Tribe's flagging ofthe exceedances on September 14, September 20 and October 26, 2006 as caused by exceptional events.
VII. Summary ofExceedances From 2004 Through 2006

The table below provides a summary ofexceedances relevant to today's proposed rule that were recorded at monitors located within the boundaries of theSJV. The table indicates, whether in determining attainment, EPA has excluded orproposes 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 ofdays peryear with levels above 150gg/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 ofthe monitoring locations are meeting the PM-10 standard.

TABLE SUMMARIZING 

### PM-1024-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 Reasonfor 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 andWildfireson September 22 andOctober 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 thepublic or EPA. Atthat time CARB and the Districthad 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 forWithdrawal (PFW)and the accompanying Jan Null declaration, the State had notyet submitted the complete documentation for the September and October 2006 exceedances on which EPA is basing this proposed rule. Therefore Earthjustice's conclusion inthe petitions thatthe September 22, 2006 and October 25, 2006 exceedances do
not qualify as natural events does not address thetechnical analysis of the winds and wildfires as ultimately submitted bythe State and which EPA has evaluated in section V. above. To

- the extentthat Earthjustice's
assessments in the petitions ofthe
nature and effect ofthe winds and wildfires arecurrently relevant, we believe our evaluation in section V. addresses the significant pointsraised in them.

In addition, since EPA, as stated in section V. above, agrees with the petitioners thatregional transport from north ofthe SJV and the northern SJV and wildfires were notthe cause ofthe exceedances on September 22 and October 25, it is unnecessary forEPA to further address the arguments raised by petitioners with respect tothese theories.

B. Notice/CommentonSeptember22 andOctober 25, 2006Exceedances
The gravamen ofthe 2006 petition, which is reiterated inthe Petition for Withdrawal, is Earthjustice's claim that EPA did not provide thepublic with an opportunity to comment onthe 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 byexceptional 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 EPAbelieves 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 thatthe areais in attainment." 71 FR 63642. Thus the data hadnot 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 onexcluding 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 tothese data, EPA determines that the data do not qualify for exclusion under EPA's natural events policy, andEPA further believes that if included that they would establish that the area is in violation oftheNAAQS, EPA will proceed with appropriate rulemaking action to withdraw its determination ofattainment." Id.It was thus clear thatEPA's determination was subject torevision based onsubsequent quality assurance andevaluation ofthe 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 ofthe potential exceptional events.

In this proposed rule, EPA is following through with this procedure, and is nowproviding forfull notice and

an opportunity for comment, inthe
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 SantaRosa Rancheria on September 14 and 20 and October 26, 2006.

Contrary toEarthjustice's contention in its Petition for Reconsideration and Petition for Withdrawal, EPA did not

reverse the burden ofproofrequired to establish an exceptional event, or relieve the State fromthe obligation to document its claims. PFRat 4; PFW at 17. In the final determination, itis clear thatEPA did not conclusively concur in excluding the datawithout requiring appropriate documentation and a showing from the State. Rather, EPA deferred its determination on the impact ofthe preliminary data untilthe data could be quality assured and the State wouldhave an opportunity to meet its burden of showing that an exceedance qualified as causedby an exceptional
event.

.Finally EPA notes thatEarthjustice 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 afterEPA promulgated its final determination of attainment, on October 17, 2006. (The notice was published on October 30,but the determination hadbeen signed and disseminated to the public on October 17). Thus,EPA had no information on these exceedances at the time ofits final action.

C. Wind Conditionsin the Valley

With respect to the existence ofhigh winds in the Valley generally, Earthjustice, in both petitions, characterizes statements in the 2003 PM-10 Plan for the area as concluding that wind erosionis not a significant contributing factor in dustemissions and as suggesting that winds with enough velocity to cause erosion disperse PM-tO concentrations and/or transport PM-tO outoftheValley. PFR
at4; PFW at8. Earthjustice in its 2007 petitionalso cites a letter fromthe District to EPA which states that "there is no evidence ofany significant linkage between high winds and PM-10 federal exceedance events [inthe Valley]." Id.
at 8-9.

Earthjustice has taken the statements inthe 2003 Plan to attainthe PM-10 standard out ofcontext. Chapter 2 ofthe Plan, quoted by Earthjustice, is a 12- page general overview ofthe San Joaquin Valley Air Basin, the purpose of which is to describe normal ortypical meteorological conditions. Itis not intendedto nor does it address unusual winds such as those under consideration here thatmay occur in the Valley. Nevertheless, the District did' determine that windblown dust is nota significant problem in the SJV for the
purposes ofattaining the PM-tO standard. For example, thePlan states that "[w]ind related PM-10 events are

rare butpossible when conditions are right" and that "PM-tO readings in the
SJVAB aremost 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-ofthe Valley" in explaihihg'whytthe spring and 

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summer months, which are the windier months ofthe yearin the SJV,donot yield higher PM-10 levels.

However, the factthat PM-10 pollution from windblown dust is not generally a significant enough problem in the SJV that itneeds to be controlled for the purposes of attaining the PM-10 standard, doesnot mean that windblown dust cannot cause an exceedance ofthe standard. In addition,

even ifwindblown 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
tocontrol 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 ifcertain 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 caseby casebasis 72 FR 13560. For example, not allhigh wind days will lead to exceedances and not all exceedances monitored when high winds arerecorded are necessarily due
tothose 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 theExceptional Events Rule requirements, and thus the data for these particular events should be excluded from regulatory consideration.

Earthjustice also cites a letterfrom the Districtto EPAresponding to a letter from Charles Swanson to EPA commenting onthe 2003 PM-10 Plan. April 15, 2004 letter fromJames 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 oftheDistrict's proposed Agricultural Conservation Management Practices:

The SJVdoes nothave a windblown dust problem to anywhere nearthe extent ofthe other nonattainment areas. The SJVhas some- ofthe lowestaverage wind speeds inthe country.Nowind related exceedances have been recorded inthebasin duringthe last three years. Wind speeds are highestduring the spring when PM-10 levels are attheir lowest. The majority ofthefugitive dust emissions aregenerated from earthdisturbingactivities. Certain soil types and cropsare more prone to windblown dustproblems. The "Other" category willgive the farmers withthe 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 ofthe 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 notreport wind gusts and the 1 in 6 day sampling forPM-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 ofpast events indicates that often the area with thehighest PM-10 levels is not where the wind ishighest, but rather wherethe wind begins to slow.To understandthe dynamics ofthis pattern we need only review the mechanisms for entrainment and deposition. When the wind slows, itcan no longer keep the larger PM10particles aloft and they settle toward the surface. The settling ofparticulates aloft * * * resultsin an increased concentration inthe 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'sNaturalEventsPolicy

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 ofthe 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'sExceptional Event Rule and not under itspre-existing policies. TheRule does not require either a showing that BACM was in place at the time ofthe event or proofthat sources were in compliance. Rather, in the preamble to the Rule EPA states that the Statemust take reasonable and appropriate

measures under these circumstances. 72 FR at 13576-135 77. That said, -EPAhas approved theDistrict's BACM demonstration for all significant sources ofPM-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 tomeet the requirements ofits 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 ofa 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 ofthese factors was offered. PFW at 11.

Earthjustice's statements regarding the requirements for documentation under the District's "Natural Events Action Plan for HighWind Events in the San Joaquin Valley Air Basin," February 16, 2006 (NEAP) appear in the portion ofits 2007 petition thataddresses the causal relationship between high winds and the September 22, 2006 exceedances. Id.. Section 3 ofthe NEAP concerns the documentation ofhigh wind events and lists specific sources ofdocumentation suggested by EPA: Filter analysis, meteorological data, modeling and receptor analysis, videos and/or photographs, maps, news accounts and BACM 97 requirements. Section 6 ofthe NEAP concerns meteorological forecasting criteria. This section states thatifcertain 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 ofit.EPA believbs that

07As 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 allexceptional events

as discussed above in section V.A.

Finally we note again that EPA is proceeding inthis rulemaking under its Exceptional Events Rule rather than the 1996policy itreplaces. In the preamble
to the Rule, EPA explained that "following the promulgation ofthis rule, Stateswill no longer be required to keep NEAPs inplace that were not approved as apart of a SIP for an area." 72 FRat 13576.

E.HarvestActivities

Earthjustice asserts in its 2006 petition that September is the peak harvest season for cotton and almonds and thatEPA should investigate the contribution ofthese activities tothe September 22 exceedances. PFR at 6. In the 2007 petition Earthjustice states that the end ofOctober is generally when
two ofthe dustiest crop harvests, cotton and almonds, take place and thatthese activities caused the October 25 exceedances. PRW at 13-14. EPA discusses the effect ofanthropogenic

sources onthe 2006 exceedances in section V. above.

F. Exceedancesat Corcoranand Stockton in 2004,Bakersfieldin 2005 andthe SantaRosaRancheriain 2006

The 2007petition raises issues regarding several exceedances thathave already been addressed by the October 2006 attainment determination. These exceedances occurred on September 3, 2004 atCorcoran and Stockton and on November 22-23, 2005 at Bakersfield. EPA's position onthese exceedances is found inthe 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 itis irrelevant because "even ifEPAhad not concurred with the exclusion ofthis data, the Corcoran site would still attainthe 24-hour NAAQS * * *." Earthjustice takes this positionbecause itbelieves there are

now other exceedances at Corcoran that
cannotbe 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 arenow other exceedances that cannot be excluded. As discussed above, EPAbelieves 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 inits determination ofattainment that "[elven if the Bakersfield-Golden State Highway BAM and TEOM data are considered together (andeven ifthey

were quality-assured data not subject to natural events), the exceedances recorded at these-monitors would not show that the area is in violation ofthe standard." 71 FR at 63659. As discussed above, EPA believes thatthe exceedances at Bakersfield in 2006 were due toexceptional events and is proposing to concur with the State's request to flag these data. Thus we still believe thatthe 2005 Bakersfield-Golden exceedances, when considered for purposes ofour 2006 attainment determination, would not contribute to

or constitute a violation.

In the 2007 petition Earthjustice also raises questions about exceedances recorded atthe 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 andExecutive 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 ofManagement and Budget. Forthis 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 rulewill nothave 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, itdoes not contain anyunfunded mandate or significantly or uniquely affect small governments, as described inthe Unfunded Mandates Reform Act of1995 (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 inputby tribal officials in the development of regulatory policies that have tribal implications." Several Indian tribes have reservations located within the boundaries ofthe SJV. EPA is aware of only one tribe in the SJV that operates

a PM-10 monitor,the SantaRosa Rancheria. EPA has consulted with representatives ofthe Santa Rosa Rancheria Tribe on the data recorded by their monitor, and the flagging ofthe data, and willcontinue to work with the Tribe, as provided for inExecutive Order 13175. Accordingly, EPA has addressed Executive Order 13175 to the
extent thatit.applies tothis action: This proposed action also,does nothave Federalism implications because it does
not have substantial direct effects on the States, onthe relationship between the national government and the-States, or
onthe distribution ofpower and responsibilities among the various levels of government, as specified in Executive Order 13132 (64FR 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 ofpower 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 oftheir programs, policies, and activities on minority and low-income populations. Today's action involves proposed determinations based on air quality considerations and proposes to affirmthat the SanJoaquin area has attained the PM-10 NAAQS. Itwillnot have disproportionately high and adverse effects on any communities in the area, including minority and lowincome communities.

This proposed rule alsois notsubject
to Executive Order 13045 "Protection of Children from Environmental Health Risks and Safety Risks" (62 FR 19885, April 23, 1997), because itis not economically significant. The requirements ofsection 12(d) ofthe National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) do notapply. Thisproposed rule does not impose an information collection burden underthe provisions ofthePaperwork Reduction Act of.1995 (44 U.S.C. 3501 et seq.).


### List ofSubjects

40 CFRPart 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 CFRPart 81

Environmental protection, Air pollution control, National parks, Wilderness areas. Dated: August 15, 2007. Wayne Nastri, Regional Administrator, Region9. [FR Doc.E7-16693 Filed 8-24-07; 8:45 am]
BILLING CODE 6560-50-P 

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