California Infrastructure SIP 

Emergency Episode Planning 

Technical Support Document 

Evaluation of California Infrastructure SIPs for CAA section 110(a)(2)(G)/emergency 

episode planning

U.S. EPA, Region 9 

September 2014 
1 

Table of Contents 

Table of Contents......................................................................................................................... 1

Summary ...................................................................................................................................... 1

Statutory and Regulatory Requirements ...................................................................................... 1

Guidance....................................................................................................................................... 3

Evaluation Introduction................................................................................................................ 3

Evaluation of State’s Authority.................................................................................................... 4

Emergency Episode Contingency Plans for 1997 and 2008 Ozone NAAQS.............................. 6

Emergency Episode Contingency Plans for 1997, 2006, and 2012 PM2.5 NAAQS .................. 10

Emergency Episode Contingency Plans for 2008 Pb NAAQS.................................................. 16

Emergency Episode Contingency Plans for 2010 NO2 NAAQS ............................................... 19

Emergency Episode Contingency Plans for 2010 SO2 NAAQS................................................ 20

Summary 

We have evaluated California’s Infrastructure State Implementation Plan (SIP) Submittals with respect 

to the emergency episode planning requirements of Clean Air Act (CAA, or the Act) section 

110(a)(2)(G) and 40 Code of Federal Regulations (CFR) part 51, subpart H (“Prevention of Air 

Pollution Emergency Episodes”). In the following pages, we describe the requirements, summarize 

California’s submittals, and present our evaluation for emergency episode planning for each applicable 

air pollutant. 

We have concluded that California’s Infrastructure SIP Submittals and certain state statutes provide for 

authority for the state and air districts comparable to that granted to the U.S. Environmental Protection 

Agency (EPA) Administrator to act in the face of an imminent and substantial endangerment to public’s 

health or welfare, or the environment. We propose to grant five of California’s ten requests to reclassify 

air quality control regions (AQCRs) for ozone, NO2, or SO2, thereby relieving such areas of the 

requirement to have an emergency episode contingency plan for a given set of air pollutants. We also 

propose to reclassify Great Basin Valley and San Joaquin Valley AQCRs for particulate matter (PM). 

We propose to approve a new particulate matter (PM) emergency episode rule for Great Basin Valley 

into the California SIP. Finally, for those AQCRs that are required to have emergency episode 

contingency plans, we find that California’s Infrastructure SIP Submittals and the California SIP provide 

such plans for the five air pollutants that are subject to this rulemaking, except Mountain Counties 

AQCR for ozone and San Joaquin Valley AQCR for PM.1

Please refer to our Overarching Technical Support Document (TSD), which accompanies this TSD, for 

our general summary and background of California’s Infrastructure SIP Submittals, which national 

ambient air quality standards (NAAQS) those submittals address, and references to applicable EPA 

guidance memos. In particular, the abbreviations for submittals and guidance titles (e.g., California’s 

2014 Submittal, 2013 Infrastructure SIP Guidance, etc.) are incorporated by reference into this TSD. 

Statutory and Regulatory Requirements 

Section 110(a)(2)(G) of the CAA requires infrastructure SIPs to “provide for authority comparable to 

that in [CAA section 303],” which reads as follows: 

 

1 See Appendix A (“California Air Quality Control Regions, Classifications, and Regulations”) to this TSD. 
2 

Notwithstanding any other provision of this chapter, the Administrator, upon receipt of evidence 

that a pollution source or combination of sources (including moving sources) is presenting an 

imminent and substantial endangerment to public health or welfare, or the environment, may 

bring suit on behalf of the United States in the appropriate United States district court to 

immediately restrain any person causing or contributing to the alleged pollution to stop the 

emission of air pollutants causing or contributing to such pollution or to take such other action 

as may be necessary. If it is not practicable to assure prompt protection of public health or 

welfare or the environment by commencement of such a civil action, the Administrator may issue 

such orders as may be necessary to protect public health or welfare or the environment. Prior to 

taking any action under this section, the Administrator shall consult with appropriate State and 

local authorities and attempt to confirm the accuracy of the information on which the action 

proposed to be taken is based. Any order issued by the Administrator under this section shall be 

effective upon issuance and shall remain in effect for a period of not more than 60 days, unless 

the Administrator brings an action pursuant to the first sentence of this section before the 

expiration of that period. Whenever the Administrator brings such an action within the 60-day 

period, such order shall remain in effect for an additional 14 days or for such longer period as 

may be authorized by the court in which such action is brought. 

Thus, the EPA Administrator has authority to bring suit to immediately restrain an air pollution source 

that presents an imminent and substantial endangerment to public health or welfare, or the environment. 

If such action may not practicably assure prompt protection, then the Administrator has authority to 

issue temporary administrative orders to protect the public health or welfare, or the environment, which 

can be extended if the Administrator subsequently files a civil action. 

EPA promulgated regulations for emergency episodes in 1971 and revised those regulations in 1986 to 

clarify state requirements related to emergency episodes found in section 110(a)(2)(G). These 

regulations appear at 40 CFR part 51, subpart H (51.150 through 51.153). The following is addressed in 

each sub-section: 

· 51.150 – how regions are classified for sulfur oxides (SOx), PM, carbon monoxide (CO), 

nitrogen dioxide (NO2), and ozone; 

· 51.151 – the requirement for a contingency plan for any region classified as Priority I to prevent 

air pollution levels from reaching the significant harm levels (SHLs) established therein; 

· 51.152 – the specific content requirements for a contingency plan; a requirement that regions 

classified as Priority IA or II have a contingency plan that addresses a subset of those content 

requirements; a provision that regions “classified Priority III do not need to develop episode 

plans;” and an exemption mechanism for the Administrator; and 

· 51.153 – how states should review the classification of regions using the most recent three years 

of data; and a requirement to revise emergency episode plans if a higher classification is 

warranted by the recent air pollution levels.2

 

2 We interpret 40 CFR 51.153 as establishing a means for states to review air quality data and request a higher and lower 

classification for any given region, while the requirement to revise emergency episode plans applies only if a region is to be 

reclassified to a higher priority (e.g., to Priority I). In other words, states can retain their emergency episode plans, even if the 

air quality data indicate that the likelihood of an air pollution emergency has decreased. EPA must respond to reclassification 

requests in rulemaking as we bear the responsibility for revising the classification of any such region in each state’s 

respective SIP. 
3 

Guidance

EPA has issued several national memos that provide guidance on emergency episode planning, 

including the 2007 Infrastructure SIP Guidance (for the 1997 ozone and 1997 fine particulate matter 

(PM2.5) NAAQS), the 2009 Infrastructure SIP Guidance (for the 2006 PM2.5 NAAQS), the 2011 

Infrastructure SIP Guidance (for the 2008 lead (Pb) NAAQS), and the 2013 Infrastructure SIP Guidance 

(for the 2008 ozone, 2010 NO2, 2010 sulfur dioxide (SO2), and all future NAAQS). The latter represents 

EPA’s most recent guidance, which we summarize at the outset of this TSD given its broad 

applicability, while the older guidance memos, which addressed only one or two pollutants, are 

summarized in their respective sections below.3

EPA’s 2013 Infrastructure SIP Guidance states that the best practice for states is to submit, for inclusion 

in the SIP, the statutory or regulatory provisions that provide authority comparable to CAA section 303 

or to cite and include a copy of such provisions, without including them in the SIP, with a narrative of 

how they meet the requirements of section 110(a)(2)(G).4 The guidance also clarifies that contingency 

plans should be submitted for approval into the SIP (if not already in the SIP) for regions classified 

Priority I, IA, or II. 

It notes that EPA has not promulgated regulations to provide PM2.5 ambient air quality levels on which 

to base formal classifications, and that EPA has not established an SHL for PM2.5 or Pb. For those 

pollutants where EPA has established an SHL, the SHL is an important part of emergency episode plans 

and, for all NAAQS pollutants, “the central components of a contingency plan would be to reduce 

emissions from the source(s) at issue... and public communication as needed.” 

For PM2.5 and Pb, based on the emissions inventories and historic ambient air quality data, if a state 

believes “that it does not need a more specific contingency plan beyond having authority to restrain any 

source from causing or contributing to an imminent and substantial endangerment,” then it can provide a 

detailed rationale to that effect. For NO2 and SO2, the 2013 Infrastructure SIP Guidance states that 

ambient air quality levels approaching the SHL are likely to be due to a single facility’s malfunction, 

and therefore contingency plans may specify facility- or equipment-specific measures to be taken during 

an air pollution emergency. 

Evaluation Introduction

We first evaluated the state’s provisions that provide authority to act in the face of air pollution 

emergencies, comparable to those granted to the EPA Administrator. As California has requested 

reclassification of several regions for ozone, NO2, or SO2 emergency episode planning, we then 

determined whether to grant or deny each request consistent with the most recent three years of air 

quality data. We also considered reclassification of two regions for PM emergency episode planning. 

Finally, for those regions that remain classified Priority I, IA, or II, we evaluated whether the state has 

provided adequate emergency episode contingency plans. 

California has numerous regions classified Priority I, IA, or II for one or more air pollutants5and has 

requested that EPA reclassify several AQCRs for ozone, NO2, and SOx to reflect air quality 

 

3 With respect to the 1997 ozone NAAQS, EPA’s 2007 Infrastructure SIP Guidance simply reaffirmed the applicability of the 

existing regulations at 40 CFR part 51, subpart H. Thus, we do not include additional background on this guidance in our 

evaluation of emergency episode planning for ozone. 

4 2013 Infrastructure SIP Guidance, pp. 47-50. 

5 40 CFR 52.221 (“Classification of regions [in California]”). 
4 

improvements over the last four decades.6 California’s 2014 Submittal provides tables that name each of 

the state’s 14 AQCRs with citations to the respective area definitions in 40 CFR part 81, subpart B and 

presents the threshold concentrations for Priority I and II areas and the SHLs for ozone, NO2, and SOx.

7

We include a map of California’s AQCRs as Appendix B to this TSD.8 

Also, California’s 2014 Submittal notes that the Great Basin Valley AQCR exceeded EPA’s 

recommended threshold above which a PM2.5 emergency episode contingency plan is needed and 

indicates that, at the time of California’s 2014 Submittal, Great Basin Unified Air Pollution Control 

District (APCD) was in the process of developing such a contingency plan. 

Given these facets of California’s emergency episode planning landscape, we have broken our 

evaluation into several sections – one section to address the authority requirement, and five sections to 

address the contingency plan requirement for each of the five air pollutants addressed by California’s 

Infrastructure SIP Submittals. Our discussion of reclassification of AQCRs for ozone, NO2, SOx, and 

PM are included in the evaluation sections for each respective pollutant. 

Evaluation of State’s Authority 

California’s response to this requirement 

California’s Infrastructure SIP Submittals consistently cite California Health and Safety Code (HSC) 

Section 42400, et seq. as vesting the California Air Resources Board (ARB) and the air districts with 

authority comparable to the emergency powers granted to the EPA Administrator under CAA section 

303.9 They also note that these state laws apply to a range of emission violations and impose penalties 

equivalent to or exceeding federal penalties for comparable violations. 

California’s 2011 Submittal additionally states that: 

ARB and districts are authorized to take action to halt pollutant emissions that could cause a 

public health emergency or nuisance. California Health and Safety Code section 41509 specifies 

that ARB or other local agency rules cannot infringe upon a district’s authority to declare, 

prohibit, or abate a nuisance. This section also specifically authorizes California’s Attorney 

General to enjoin any pollution or nuisance, at the request of a district or ARB.10 

California’s 2014 Submittal reiterates the statement regarding HSC Section 41509 and further states 

that: 

ARB is responsible for controlling emissions from vehicular sources, while districts are 

responsible for controlling emissions from non-vehicular sources. Under H&SC Section 41700, 

sources are prohibited from emitting any pollutant(s) that cause injury, detriment, nuisance, or 

 

6 California’s 2012 Submittal, Enclosure 1, Appendix A, p. A-11 (reclassification request with respect to NO2); and 

California’s 2014 Submittal, Enclosure 1, pp. 28, 31-32 (reclassification request with respect to ozone and SOx). 

7 California’s 2014 Submittal, Enclosure 1, p. 30, Table 11 and p. 31, Table 12. 

8 The 14 federal AQCRs closely, but not exactly, correspond to the 15 air basins defined in California’s Code of Regulations 

(CCR) Title 17 (“Public Health”), Division 3 (“Air Resources”), Chapter 1 (“Air Resources Board”), Subchapter 1.5 (“Air 

Basins and Air Quality Standards”), Article 1 (“Descriptions of California Air Basins”). Notably the Salton Sea Air Basin is 

distinct from the Mojave Desert Air Basin and several air basins’ borders differ from those of the federal AQCRs, including 

the borders between the following air basins from North to South: Sacramento Valley/Northeast Plateau, San Joaquin 

Valley/Mojave Desert, South Central Coast/South Coast, and South Coast/Salton Sea. A map of these air basins is available 

at http://www.arb.ca.gov/ei/maps/statemap/abmap.htm. 

9 California’s 2007 Submittal, Appendix B, p. 5; California’s 2011 Submittal, Appendix A, p. A-9; California’s 2012 

Submittal, Enclosure 1, Appendix A, p. A-10; and California’s 2014 Submittal, Enclosure 1, p. 29. 

10 California’s 2011 Submittal, Appendix A, p. A-9. 
5 

annoyance to the public or that endanger the comfort, repose, health, or safety of the public. 

Furthermore, H&SC Section 42450, et seq., gives districts specific authority to abate emissions 

from any source violating H&SC Section 41700 or any other order, rule, or regulation that 

prohibits or limits the discharge of pollutants, consistent with applicable notice and hearing 

requirements.11

Copies of HSC Sections 41509, 41700, 42400, et seq., and 42450, et seq. appear in California’s 2014 

Submittal, Enclosure 1, Attachment 1. 

EPA’s evaluation 

We have reviewed California’s provisions, both those presented in the California Infrastructure SIP 

Submittals and in the current California Government Code (GC) and Health and Safety Code (HSC), for 

evidence that the state has authorities comparable to those in section 303. 

With regard to the authority to bring suit, HSC Section 41509 establishes that no state or district 

provision can limit, per paragraph (b), the California Attorney General’s power to bring an action to 

enjoin any pollution or nuisance, whether at the request of the state board (i.e., ARB) or a local or 

regional authority (e.g., the air districts), or on its own motion. In a similar vein, GC section 12607 

authorizes the Attorney General to “maintain an action for equitable relief... against any person for the 

protection of the natural resources of the state from pollution, impairment, or destruction.” In addition, 

GC section 12606 authorizes the California Attorney General to intervene in any judicial or 

administrative proceeding “concerning pollution or adverse environmental effects which could affect the 

public generally.” 

By virtue of using terms such as “any pollution or nuisance” and “pollution, impairment, or destruction,” 

and “pollution or adverse environmental effects” these statutes provide the Attorney General with broad 

authority, on its own motion or at the request of administrative agencies, to bring suit against persons 

causing pollution of varying degrees of urgency, including pollution that presents an imminent and 

substantial endangerment. Arguably, these provisions provide even broader authority than what CAA 

section 303 provides to EPA, as they do not by their terms first require the Attorney General to assert 

that the would-be enjoined pollution constitutes imminent and substantial endangerment. As further 

discussed below, we propose to find that these provisions, while not employing the literal definition of 

“welfare” found in CAA section 302(h) or specifically tying threats to “public health,” “welfare,” or the 

“environment” to the phrase “imminent and substantial endangerment” used in CAA section 303 and 

other federal environmental statutes as a threshold for taking action, provide authority to bring civil 

action that is nonetheless comparable to that of section 303. These provisions broadly address protection 

of public health (e.g. from pollution), welfare (e.g. from nuisance), and the environment (e.g. protection 

of natural resources from pollution, impairment, or destruction) from any imminent and substantial 

endangerment. 

California’s HSC statutes also provide for authority to issue administrative orders to protect the public 

health, welfare, and the environment when civil action may not provide such protection in a prompt 

manner. HSC Section 41700 prohibits the discharge of any air contaminant12 or other material that 

“cause injury, detriment, nuisance, or annoyance... to the public, or that endanger the comfort, repose, 

health, or safety... of the public, or that cause... injury or damage to business or property.” HSC Section 

 

11 California’s 2014 Submittal, Enclosure 1, p. 29. 

12 California’s defines “air contaminant” in California HSC Section 39013 as “any discharge, release, or other propagation 

into the atmosphere,” which includes all NAAQS. 
6 

42450, et seq. provide that an air district board may issue orders for abatement whenever it finds, among 

other things, violations of HSC Section 41700 “or of any order, rule, or regulation prohibiting or 

limiting the discharge of air contaminants into the air.” Under HSC Section 42451, an air district hearing 

board may similarly issue orders for abatement when it finds such violations. HSC Section 42450 et seq.

also provide the form of how such abatement orders and injunctions against violations are to be executed 

and the proceedings for such injunctions. In sum, HSC Section 41700 prohibits air contaminant 

discharges that endanger public health or welfare (e.g., comfort, repose, or safety) and HSC Section 

42450, et seq. provide air districts and air district hearing boards with the power to issue abatement 

orders when they find that a person is discharging an air contaminant that endangers the public health or 

welfare. 

In order to enforce such abatement orders, HSC Section 42400, et seq. provide authority and 

mechanisms for issuing criminal and civil penalties, sanctions, imposition of fines, and filing injunctions 

related to a wide variety of offenses, including: 

· Negligent emission of air contaminants, 

· Willful and intentional emissions of air contaminants, 

· Knowing violations, including those pertaining to a federally enforceable permit condition, fee, 

or filing requirement, 

· Violation of abatement order or emission limits, 

· Failure to take action, and 

· Knowing falsification of document. 

Beyond the authority already noted in HSC section 41509(b) with respect to the Attorney General’s 

authority to bring suit, HSC section 41509 establishes that no state or district provision can limit (a) the 

local air districts’ power to declare, prohibit, or abate nuisances (for example, those that may be caused 

by stationary sources); or (c) that the state agency’s (i.e., ARB’s) power to enforce or administer laws 

that it is permitted or required to enforce (such as those for mobile sources). This reinforces the air 

districts’ and ARB’s broad authority to curtail emissions of air pollution that present an imminent and 

substantial endangerment to public health or welfare or the environment by issuing orders to abate 

nuisances and enforce state air pollution laws, respectively. 

While no single California statute mirrors the authorities of CAA section 303, we propose to find that 

the combination of the GC and HSC laws discussed above provide for authority comparable to section 

303 to immediately bring suit to restrain, and issue orders against, any person causing or contributing to 

air pollution that presents an imminent and substantial endangerment to public health or welfare, or the 

environment. None of these state laws have been submitted for incorporation into the California SIP. 

However, consistent with EPA’s 2013 Infrastructure SIP Guidance, the narratives provided in 

California’s Infrastructure SIP Submittals about California’s authorities that apply to emergency 

episodes, plus additional California statutes that we have considered (i.e., GC sections 12606 and 

12607), are sufficient to meet the comparable authority requirement of CAA section 110(a)(2)(G). 

Because these laws apply to air contaminants, which by state law definition includes all NAAQS, we 

therefore propose that California has met the comparable authority requirement of CAA section 

110(a)(2)(G) for all NAAQS. 

Emergency Episode Contingency Plans for 1997 and 2008 Ozone NAAQS

California’s response to this requirement 

California’s 2007 Submittal, with respect to the 1997 ozone NAAQS, simply committed to submit any 

necessary SIP revisions upon amended guidance by U.S. EPA. 
7 

California’s 2014 Submittal, which addresses the 1997 and 2008 ozone NAAQS, asserts that “California 

air quality has improved substantially and[,] in most areas, is now much better than the specified 

thresholds” and that the SHL for ozone (2-hour: 0.6 ppm) hasn’t been reached in decades. As such, ARB 

requests that EPA reclassify the following seven AQCRs from Priority I to Priority III for ozone, with 

the resulting outcome that no contingency plan be required: 

· Lake Tahoe, Mountain Counties, North Central Coast, Sacramento Valley, San Diego, San 

Francisco Bay Area, and Southeast Desert.13

The submittal then notes that nine AQCRs were originally classified Priority I, while the remaining five 

AQCRs were classified Priority III.14 It asserts that the classifications were based on the former 1979 1-

hour ozone NAAQS and that EPA has not classified the AQCRs for the 1997 or 2008 ozone NAAQS. It 

refers to EPA’s proposed implementation rule for the 2008 ozone NAAQS as indicating that the existing 

SHL for ozone (0.6 ppm, 2-hour average) remains appropriate for the 2008 ozone NAAQS,15 and asserts 

that the proposed AQCR reclassifications would apply for the 1979, 1997, and 2008 ozone NAAQS. 

ARB then constructs an argument that California has attained the 1979 1-hour ozone NAAQS in all 

AQCRs of the state originally classified Priority I except Metropolitan Los Angeles and San Joaquin 

Valley, which would be required to retain their SIP-approved emergency episode plans. For most of the 

seven AQCRs for which ARB requests reclassification, ARB cites final rules that redesignated to 

attainment areas that had been nonattainment for the 1979 ozone NAAQS and were located within the 

various AQCRs. For the one AQCR, Southeast Desert, that has not been redesignated to attainment for 

the 1979 ozone NAAQS, the submittal cites the SIP-approved emergency episode plans for each of the 

five air districts within the AQCR. Similarly, for Metropolitan Los Angeles and San Joaquin Valley 

AQCRs, the submittal cites the SIP-approved emergency episode plans for each air district within each 

AQCR. 

Thus, ARB requests reclassification of the seven AQCRs named above from Priority I to Priority III, 

which would relieve the requirement for an emergency episode contingency plan, and states that for the 

remaining two AQCRs, the SIP contains adequate contingency plans. For the regulatory basis of the 

request, California’s 2014 Submittal cites 40 CFR 51.152(d)(1), which provides a mechanism for 

exemption from the requirements of AQCRs classified Priority I, IA, or II for the portions of such 

AQCRs that have been designated as attainment or unclassifiable. 

EPA’s evaluation 

EPA must first evaluate whether to grant or deny the reclassification requests made by ARB, consistent 

with the requirements of 40 CFR part 51, subpart H, and then evaluate the existence and adequacy of 

emergency episode plans for any AQCRs that retain a Priority I classification. 

California’s 2014 Submittal reflects a slight, but important, misconception about the basis for classifying 

AQCRs for emergency episode planning purposes. Unlike designations under CAA section 107(d), 

which are specific to a given revision of the NAAQS (e.g., the 2008 ozone NAAQS),16 classifications of 

AQCRs for emergency episode planning are merely pollutant-specific (e.g., they apply to all ozone 

 

13 See Appendix A (“California Air Quality Control Regions, Classifications, and Regulations”) to this TSD; and California’s 

2014 Submittal, Enclosure 1, Table 13 (p. 32). 

14 California’s 2014 Submittal, Enclosure 1, pp. 33-34. 

15 78 FR 34178 at 34210, June 6, 2013. 

16 Note that the system of designation classifications for nonattainment areas under the various subparts of CAA Title I, part 

D is distinct from the system of classification for emergency episode planning under 40 CFR part 51, subpart H. 
8 

NAAQS) and governed by the regulations of 40 CFR part 51, subpart H. So, we agree that ARB’s 

requested reclassifications would apply for the 1979, 1997, and 2008 ozone NAAQS, or indeed any 

future ozone NAAQS. 

In essence, the nonattainment area designations regime is designed to protect public health and welfare 

within an adequate margin of safety and involves emission control strategies that are implemented over 

months and years. By contrast, the emergency episode planning regime is designed to protect the public 

from an imminent and substantial endangerment to public health or welfare where emission reductions 

and public notification must be implemented within hours and days. 

In short, the test for classifying AQCRs is prescribed in 40 CFR 51.150. For ozone, an AQCR with a 1-

hour ozone level greater than 0.10 ppm must be classified Priority I. Consistent with the provisions of 40 

CFR 51.153, reclassification of AQCRs must rely on the most recent three years of air quality data. 

With respect to 40 CFR 51.152(d)(1), the Administrator may exempt a Priority I, IA, or II AQCR from 

the contingency plan requirements for the portions of the AQCR “which have been designated as 

attainment or unclassifiable for national primary and secondary standards under section 107 of the Act.” 

Read literally, “national primary and secondary standards” would encompass all NAAQS, not just the 

1979 1-hour ozone NAAQS. Because the emergency episode planning requirements act in parallel, but 

semi-independently, of the NAAQS, another plausible reading of “national primary and secondary 

standards” would encompass all NAAQS for a given air pollutant (e.g., the 1979, 1997, and 2008 ozone 

NAAQS). We have based our evaluation on this latter interpretation. In other words, the EPA 

Administrator has authority to exempt an area that is designated or unclassifiable for all ozone NAAQS 

from the emergency episode plan requirements for ozone. However, the Administrator must make an 

affirmative determination to such effect and an area’s attainment or unclassifiable status alone does not 

automatically exempt such an area from the emergency episode contingency plan requirements. 

Accordingly, we have reviewed California’s 2011-2013 air quality data and have determined the 

following with respect to California’s ozone AQCR reclassification requests: 

· We propose to grant reclassification for (high 1-hour ozone value for AQCR in parentheses): 

o Lake Tahoe (0.049 ppm),17 and 

o North Central Coast (0.078 ppm).18

· We propose to deny reclassification for (high 1-hour ozone values greater than 0.10 ppm, by 

relevant air district, in parentheses):19

o Mountain Counties (El Dorado County: 0.117 ppm; and Placer County: 0.111 ppm), 

o Sacramento Valley (Sacramento Metro: 0.125 ppm), 

o San Diego (San Diego County: 0.114 ppm), 

o San Francisco Bay Area (Bay Area: 0.115 ppm), and 

o Southeast Desert (Antelope Valley: 0.115 ppm; Imperial County: 0.164 ppm; Mojave 

Desert: 0.132 ppm; and South Coast: 0.127 ppm). 

As a result, California would have seven Priority I AQCRs for ozone. We then assessed the existence 

and adequacy of emergency episode plans for each of these seven AQCRs. Five of these AQCRs have 

adequate SIP-approved emergency episode rules applicable to ozone as cited in Appendix A 

 

17 See Appendix C.1 to this TSD. The Lake Tahoe AQCR has just one ozone monitor, which has been operating since 

November 2013. 

18 See Appendix C.2 to this TSD. 

19 See Appendix C.3 to this TSD. 
9 

(“California Air Quality Control Regions, Classifications, and Regulations”) to this TSD. The relevant 

air districts (in parentheses below) of these five AQCRs are as follows: 

· Metropolitan Los Angeles (Santa Barbara County, South Coast, and Ventura County), 

· San Diego (San Diego County), 

· San Francisco Bay Area (Bay Area), 

· San Joaquin Valley (San Joaquin Valley), and 

· Southeast Desert (Antelope Valley, Eastern Kern, Imperial County, Mojave Desert, and South 

Coast) 

The remaining two AQCRs that retain the Priority I classification – Sacramento Valley and Mountain 

Counties – required further evaluation. Sacramento Valley includes portions of eight air districts,20 just 

one of which (Sacramento Metro) recorded a 1-hour ozone level above 0.10 ppm during 2011-2013. 

Sacramento Metro air district already has an adequate SIP-approved emergency episode rule applicable 

to ozone.21 Mountain Counties includes portions of seven air districts,22 just two of which (El Dorado 

County and Placer County) recorded a 1-hour ozone level above 0.10 ppm during 2011-2013. Unlike 

Sacramento Metro, these two air districts do not have SIP-approved emergency episode rules. Within 

these two AQCRs, the population and concentration of emission sources is greatest in the greater 

Sacramento metropolitan area and the air districts of El Dorado County, Placer County, and Sacramento 

Metro (i.e., Sacramento County) each share a county border with one another. 

As per the requirements of 40 CFR 51.151: 

Each such plan for a Priority I region must include a contingency plan which must, at a 

minimum, provide for taking action necessary to prevent ambient pollutant concentrations at any 

location in such region from reaching the [significant harm level for]... Ozone-1,200 μg/m3 (0.6 

ppm) 2-hour average. 

At the time of promulgation of this regulation in the 1970s, the ozone air pollution levels might have 

warranted a broad number of the air districts in Sacramento Valley and Mountain Counties AQCRs to 

adopt emergency episode rules to prevent ambient ozone levels reaching the SHL. However, the ambient 

ozone concentrations in recent decades have not reached anywhere near the SHL for ozone. In fact, the 

lowest 1-hour ozone threshold for a Stage 1 alert (i.e., level at which emissions should start to be 

curtailed to avoid an ozone air pollution emergency) that appears in EPA’s example emergency episode 

regulations at 40 CFR part 51, Appendix L, or in California’s SIP-approved emergency episode rules is 

0.20 ppm. That level has not been reached anywhere in California since 1998.23

Because recent ambient air quality data do not indicate that ozone levels are likely to approach the 

general Stage 1 one-hour ozone alert level of 0.20 ppm, much less the 2-hour SHL of 0.6 ppm, we 

propose to find that to satisfy the requirements of 40 CFR 51.151 for contingency plans for these two 

AQCRs classified Priority I, California needs to provide emergency episode contingency plans for the 

three air districts that have recorded a 1-hour ozone level above 0.10 ppm. If no air district within these 

two AQCRs had recorded a 1-hour ozone level above 0.10 ppm, then we would be able to grant 

California’s reclassification request. Because only Sacramento Metro, El Dorado County, and Placer 

County air districts recorded such levels, and because no district in California has exceeded the 0.20 

ppm Stage 1 level that would trigger curtailment actions since 1998, we propose that California can 

 

20 Butte, Colusa, Feather River, Glenn, Sacramento Metro, Shasta, Tehama, and Yolo-Solano air districts. 

21 65 FR 53602, September 5, 2000. 

22 Amador, Calaveras, El Dorado, Mariposa, Northern Sierra, Placer, and Tuolumne air districts. 

23 See Appendix C.4 to this TSD. 
10 

meet its 40 CFR 51.151 obligations if the three air districts that have recorded a 1-hour ozone level 

above 0.10 ppm provide adequate emergency episode contingency plans. 

We conclude that Sacramento Valley has an adequate emergency episode contingency plan for ozone by 

virtue of the SIP-approved contingency plan for Sacramento Metro air district – the only district within 

the AQCR to have recorded 1-hour ozone levels above 0.10 ppm during the most recent three years. 

However, we conclude that Mountain Counties does not have an adequate contingency plan in place, 

and would need to provide such plans at minimum for the El Dorado County and Placer County air 

districts. 

In sum, of the AQCRs in California that remain classified Priority I, after we grant reclassification for 

Lake Tahoe and North Central Coast AQCRs, all but one – Mountain Counties – have adequate SIPapproved emergency episode contingency plans. For the AQCRs that will be classified Priority III upon 

finalization of these proposed reclassifications,24 there is no requirement for an emergency episode 

contingency plan. We therefore propose to approve California’s Infrastructure SIP Submittals for section 

110(a)(2)(G) for ozone for all AQCRs in California except Mountain Counties, which we propose to 

disapprove on the basis of the lack of an emergency episode contingency plan, as discussed above. We 

are prepared to work with El Dorado County and Placer County air districts to develop adequate 

emergency episode plans that best fit the air pollution emission concerns of these two air districts. 

Emergency Episode Contingency Plans for 1997, 2006, and 2012 PM2.5 NAAQS 

Additional Background 

EPA’s 2009 Infrastructure SIP Guidance serves as operative interim guidance for section 110(a)(2)(G) 

for the various PM2.5 NAAQS. That guidance memo recommends that a state with at least one 

monitored 24-hour PM2.5 value exceeding 140.4 μg/m3 establish an emergency episode plan and 

contingency measures to be implemented should such level be exceeded again.25 It also refers to EPA’s 

February 2007 issue paper on revising the air quality index (AQI) and setting a significant harm level 

(SHL) for PM2.5.

26 While EPA has not yet promulgated a significant harm level for PM2.5, this issue 

paper may be considered in the course of state and EPA discussions on the framing and content of any 

emergency episode plan for PM2.5 that may be necessary to adequately implement a state’s emergency 

episode authority pursuant to CAA section 110(a)(2)(G). 

Given the provision of 40 CFR 51.153(a) for states to review the most recent three years of air quality 

data, we reviewed California’s 24-hour PM2.5 air quality data from 2011-2013.27 Upon identifying areas 

that recorded 24-hour PM2.5 values above 140.4 μg/m3 during this period, we considered the appropriate 

classification of such areas based on the provisions of 40 CFR 51.150 for PM, for which we also 

reviewed California’s 24-hour PM10 data.28 Unlike the thresholds for ozone, NO2, SOx, and CO that rely 

on monitoring of distinct indicator pollutants, the thresholds for PM are simply for “particulate matter” 

 

24 These include the following seven AQCRs: Great Basin Valley, Lake County, Lake Tahoe, North Central Coast, North 

Coast, Northeast Plateau, and South Central Coast. 

25 2009 Infrastructure SIP Guidance, pp. 6-7 and Attachment B (“Recommended Interim Significant Harm Level, Priority 

Levels, and Action Levels for PM2.5 Emergency Episode Plans (EEPs)”). 

26

“Revising the Air Quality Index and Setting a Significant Harm Level for PM2.5,” EPA’s Office of Air Quality Planning 

and Standards Issue Paper for Discussion at National Air Quality Conference, February 2007. 

27 See Appendix D.1 to this TSD. This spreadsheet also includes 2010 data since ARB had reviewed 2010-2012 data during 

its development of California’s 2014 Submittal. 

28 See Appendix D.2 to this TSD. 
11 

and therefore do not distinguish between PM2.5 and PM10. The thresholds for PM classification for 

Priority I and II are as follows: 

· Priority II: annual geometric mean between 60-95 μg/m3; 24-hour max. between 150-325 μg/m3. 

· Priority I: annual geometric mean greater than 95 μg/m3; 24-hour max. greater than 325 μg/m3. 

This could present a case where PM2.5 measurements imply a different and lower classification than 

PM10 measurements since PM2.5 is a component of PM10. For instance, if an area recorded PM values 

during 2011-2013 of 200 μg/m3 for 24-hour PM2.5 and 350 μg/m3for 24-hour PM10, the PM2.5 value 

would imply a classification of Priority II while the PM10 value would imply a classification of Priority 

I. Therefore, we propose to classify such areas based on PM10 values (of which PM2.5 is a component), 

where available, in order to ensure adequate protection from PM emergency episodes as a whole. 

Following classification, however, we also propose that such differences could be relevant in 

determining the adequacy of a PM emergency episode plan. For instance, if the PM2.5 values for an area 

imply classification as Priority III, for which no emergency episode plan is required, and the PM10

values imply classification as Priority II, then a PM emergency plan that included episode criteria for 

PM10, but not PM2.5, could be adequate to meet CAA section 110(a)(2)(G) for PM as a whole. 

California’s response to this requirement 

California’s 2014 Submittal, which addresses the 1997 PM2.5, 2006 PM2.5, and 2012 PM2.5 NAAQS for 

CAA section 110(a)(2)(G), refers to EPA’s 2009 Infrastructure SIP guidance and states that during 2010 

to 2012, 24-hour PM2.5 concentrations at California’s federal reference method (FRM) monitors were no 

greater than 140.4 μg/m3 with one exception.29 On December 1, 2011, a concentration of 208 μg/m3 was 

recorded at the Keeler-Cerro Gordo Road monitor in Great Basin Unified APCD due to a windblown 

dust event. ARB requests that EPA treat Great Basin Valley as a Priority II region, and all other regions 

of the state as Priority III, for emergency episode classification purposes. 

The submittal asserts that high concentrations in Great Basin Valley “are caused by windblown dust 

from the anthropogenically-dried Owens Lake bed and are unique to the Great Basin Valley area” and 

that best available control measures (BACM) are already in place for most of the emissive area of the 

lake bed, with more to come over the next few years. It notes that Great Basin Unified APCD has an 

existing health advisory program for high wind dust events and that the air district was planning to adopt 

an emergency episode rule for windblown dust and smoke-related impacts for incorporation into the 

California SIP. 

Great Basin Unified APCD Rule 701 (“Air Pollution Episode Plan for Particulate Matter”), was adopted 

by the air district’s board on March 3, 2014 and submitted by ARB to EPA on June 2, 2014 (Great Basin 

Rule 701). The rule establishes requirements for episode criteria (i.e., hourly PM10 and PM2.5 ambient air 

concentrations at which certain actions must be taken), measuring ambient air quality, notifying the 

public, special actions for prescribed burns, inter-district coordination, and episode termination, and 

provides a regulatory basis for investigating the nature of the air pollution episode and determining if 

any abatement actions could be taken. It is accompanied by the Great Basin Unified APCD’s Supporting 

Technical Document (Great Basin’s 2014 TSD), which provides background and technical analysis for 

the rule. Among other things, Great Basin’s 2014 TSD notes that the Rule 701 is a refined and expanded 

version of the district’s health advisory program that has been in place since 1995.30 The submittal also 

includes adverse comments from Los Angeles Department of Water and Power and the air district’s 

responses thereto. We address the specific details of Great Basin Rule 701 in our evaluation below. 

 

29 California’s 2014 Submittal, Enclosure 1, pp. 34-35. 

30 Great Basin Rule 701, Staff Report, p. 1. 
12 

EPA’s evaluation 

As an initial screen, we reviewed 24-hour PM2.5 air quality data from California’s FRM and federal 

equivalent method (FEM) monitors during 2011-2013, as well as data from 2010, consistent with the 

2010-2012 period used by ARB in its review, to identify areas where concentrations exceeded EPA’s 

recommended threshold.31 For the identified areas, we also reviewed the 24-hour PM10 data from the 

FRM and FEM monitors available in those areas to determine the appropriate emergency episode 

classification under 40 CFR 51.150. 32 We then evaluated the provisions applicable to such areas against 

the CAA section 110(a)(2)(G) requirement that the SIP include adequate emergency episode 

contingency plans and against EPA’s implementing regulations at 40 CFR part 51, subpart H. 

There were two occasions where the concentrations exceeded 140.4 μg/m3: 

· 208 μg/m3 on December 1, 2011 at the Keeler-Cerro Gordo Road monitor operated by Great 

Basin Unified APCD in the Keeler Dunes and Owens Lake area of Inyo County, and 

· 167 μg/m3 on May 5, 2013 at the Bakersfield-Planz monitor operated by ARB in San Joaquin 

Valley. 

California’s 2014 Submittal requested that we treat all areas of the state as though they were classified 

Priority III, with the exception of Great Basin Valley, for which ARB requested treatment as a Priority II 

area. ARB did not make any special request for San Joaquin Valley, which resulted from their review of 

2010-2012 data, without supplemental review of the preliminary data for 2013. However, we must 

consider this recent data, consistent with 40 CFR 51.153(a). 

The FRM and FEM monitors in Great Basin Valley AQCR recorded over 90 instances during 2011-

2013 where 24-hour PM10 levels exceeded the Priority I threshold of 325 μg/m3. As such, we propose to 

revise the PM emergency episode classification of Great Basin Valley AQCR from Priority III to 

Priority I in 40 CFR 52.221. The FRM and FEM monitors in San Joaquin Valley AQCR recorded 15 

instances during 2011-2013 where 24-hour PM10 levels were within the Priority II range of 150-325 

μg/m3, with no exceedances of the Priority I threshold of 325 μg/m3 during that time. We therefore 

propose to revise the PM emergency episode classification of San Joaquin Valley AQCR from Priority I 

to Priority II in 40 CFR 52.221. Based on these classifications, we have reviewed the adequacy of each 

area’s PM emergency episode plans. 

As per the requirements of 40 CFR 51.152:

(a) Each contingency plan must— 

(1) Specify two or more stages of episode criteria such as those set forth in appendix L to this 

part, or their equivalent; 

(2) Provide for public announcement whenever any episode stage has been determined to 

exist; and 

(3) Specify adequate emission control actions to be taken at each episode stage. (Examples of 

emission control actions are set forth in appendix L.) 

(b) Each contingency plan for a Priority I region must provide for the following: 

(1) Prompt acquisition of forecasts of atmospheric stagnation conditions and of updates of 

such forecasts as frequently as they are issued by the National Weather Service. 

(2) Inspection of sources to ascertain compliance with applicable emission control action 

requirements. 

 

31 See Appendix D.1 to this TSD. 

32 See Appendix D.2 to this TSD. 
13 

(3) Communications procedures for transmitting status reports and orders as to emission 

control actions to be taken during an episode stage, including procedures for contact with 

public officials, major emission sources, public health, safety, and emergency agencies and 

news media. 

(c) Each plan for a Priority IA and II region must include a contingency plan that meets, as a 

minimum, the requirements of paragraphs (b)(1) and (b)(2) of this section. Areas classified 

Priority III do not need to develop episode plans. 

Stemming from 40 CFR 51.152(c) and our data review, California does not need to develop emergency 

episode contingency plans for PM2.5 for any region classified Priority III for PM and therefore meets the 

requirements of CAA section 110(a)(2)(G). For the two remaining regions – Great Basin Valley and San 

Joaquin Valley – we present our evaluation of their emergency episode rules below. 

Great Basin Valley 

Background for Rule 701 

As described in Great Basin’s 2014 TSD, Great Basin Valley is composed of desert, forest, and alpine 

ecosystems, has a small population and few emission sources, and is located at the eastern edge of the 

Sierra Nevada Mountains.33 Topographical and meteorological conditions often produce high wind 

events. In the area of the dry lakebed of Owens Lake and its surrounding dunes, such high winds entrain 

dust from the lakebed and dunes resulting in very high PM10 and PM2.5 concentrations at the surrounding 

communities and monitoring sites. For instance, the air district’s monitors have recorded numerous 24-

hour PM10 concentrations above the classification threshold for a Priority I area of 325 μg/m3found at 

40 CFR 51.150(b).34 Furthermore, Great Basin’s 2014 TSD describes the high wind event of December 

1, 2011 as having hourly average wind speeds over 45 miles per hour wherein the Keeler-Cerro Gordo 

Road monitor recorded a 24-hour PM2.5 level of 208 μg/m3 – well above the recommended threshold for 

a Priority II area – and a 24-hour PM10 level of 2,994 μg/m3.

35

The areas surrounding Mono Lake and Owens Lake, in Mono and Inyo counties, respectively, are 

designated nonattainment for the 1987 PM10 NAAQS. Water from each lake has historically been 

diverted for use by the City of Los Angeles, resulting in the appearance of the dry lakebeds. For most 

years since 2000, the monitors around either Mono Lake or Owens Lake have recorded the highest PM10

levels in the nation, as shown in Figure 2.1 of Great Basin’s 2014 TSD. Beyond the severe fugitive dust 

levels observed in the Great Basin Valley, its counties also experience high PM levels as a result of 

infrequent wildfires in the Sierra Nevada Mountains, as was the case with the large Aspen and Rim fires 

in summer 2013, which impacted several Great Basin Valley communities. 

Because of the unique challenge in Great Basin Valley posed by high PM levels from windblown dust, 

the air district has implemented a health advisory program in the Owens Lake area since 1995 that alerts 

the public when high PM levels occur and describes protective measures to be taken to reduce the 

public’s exposure. As described in California’s 2014 Submittal and Great Basin Rule 701, that health 

advisory program has now been refined, expanded (to cover the whole air district and to address wildfire 

smoke impacts), adopted, and submitted to EPA for inclusion in the SIP as Rule 701.36

 

33 Great Basin’s 2014 TSD, p. 3. 

34 Id. at 1. 

35 The relationship between wind speed and PM levels (i.e., high winds produce high PM levels) is shown in Great Basin’s 

2014 TSD, Figures 4.1 and 4.2. 

36 California’s 2014 Submittal, Enclosure 1, pp. 34-35 and Great Basin’s 2014 TSD, pp. 1-2. 
14 

Evaluation of Rule 701 

We have evaluated Rule 701 against the requirements of 40 CFR part 51, subpart H as follows. 

Paragraph C.4 specifies two stages of episode criteria using hourly PM10 levels for dust and wildfire 

smoke and hourly PM2.5 levels for dust. It also requires that a Stage 1 or Stage 2 health advisory be 

issued when ambient air concentrations exceed the episode criteria. These criteria are summarized in 

Attachment 1 to Rule 701 and are reproduced in the table below. 

Table 1: Great Basin Unified APCD Rule 701, Attachment 1 (“Episode Criteria”)

For the purpose of Rule 701, the following episode criteria shall apply: 

Air Pollutant Averaging 

Time 

Stage 1 Health Advisory Stage 2 Health Advisory 

PM10 - Dust 1 Hour 400 μg/m3 800 μg/m3 

PM2.5 - Dust 1 Hour 150 μg/m3 300 μg/m3 

PM10 - Wildfire Smoke 1 Hour 100 μg/m3 200 μg/m3 

The levels for each respective stage in Rule 701 are higher than those listed in 40 CFR 51.150(b) for PM 

(Priority II: 24-hour PM between 150-325 μg/m3; Priority I: 24-hour PM above 325 μg/m3) and in 

EPA’s 2009 Infrastructure SIP Guidance for PM2.5 (Priority II: 24-hour PM2.5 greater than 140.4 μg/m3). 

Also, the 1-hour averaging time is shorter than the 24-hour averaging period that appears in EPA’s 

regulations and guidance. The following reason is given for the shorter averaging period: 

...elevated PM events within the District are typically short in duration, yet drastic and extreme 

in regards to pollution exposure levels. Because of these unique circumstances in the [Great 

Basin Unified APCD], the need for hourly monitoring breakpoints is pertinent to achieving 

adequate public health protection goals.37

Great Basin’s 2014 TSD then presents analysis of the protectiveness of the episode criteria selected for 

Rule 701 by reviewing available data (1993-2013 data for PM10 and 2009-2013 data for PM2.5 at the 

Keeler-Cerro Gordo Road monitor) against the federal 24-hour thresholds. The analysis concludes that 

the Stage 1 one-hour thresholds captured all instances where the federal 24-hour PM10 NAAQS (150 

μg/m3) and 24-hour PM2.5 NAAQS (35 μg/m3) were exceeded and that the Stage 2 one-hour thresholds 

captured all instances where the federal 24-hour PM10 and PM2.5 levels for the air quality index (AQI) 

category of Hazardous 1/warning were exceeded.38 For example, the PM2.5 Stage 2 one-hour dust 

threshold of 300 μg/m3captured all instances where the Hazardous 1/warning threshold of 250.5 μg/m3

was exceeded, and even all instances exceeding the Priority I level of 210.5 μg/m3recommended by 

EPA’s 2009 Infrastructure SIP Guidance. Therefore, Great Basin’s 2014 TSD asserts that the 

combination of the 1-hour averaging period and selected levels are slightly more protective than the 

federal standards. We have reviewed this analysis and agree with its conclusions. The episode criteria 

are adequate for PM10 and PM2.5 emergency episode planning purposes. 

In addition, Rule 701 includes thresholds for PM10 for wildfire smoke to leverage data from several 

continuous PM10 monitors throughout Great Basin Valley as a surrogate for PM2.5 data since the air 

district operates only one continuous PM2.5 monitor (i.e., in Keeler). The tighter PM10 thresholds for 

 

37 Great Basin’s 2014 TSD, p. 16. Note also in Figure 5.1 that when the PM10 levels exceed the SHL (600 μg/m3

), the PM10

levels on the following day are all below the SHL. Thus, the opportunity to notify the public during the first 24 hours when 

the air pollution is worst would be lost if a 24-hour averaging time were used in the episode criteria. 

38 Great Basin’s 2014 TSD, p. 18 and Figures 5.2 and 5.3. Also, for more information on the federal AQI, see 40 CFR part 

58, Appendix G (“Uniform Air Quality Index (AQI) and Daily Reporting”). 
15 

wildfire smoke relative to those for dust reflect the general premise that PM2.5 represents a higher 

proportion of PM10 in wildfire smoke than in windblown dust. Given that the PM10 wildfire smoke 

thresholds are more stringent than the PM10 and PM2.5 thresholds for dust, they are adequate for 

purposes of meeting the emergency episode planning requirements for PM10 and PM2.5 in the event of 

wildfire. Thus, Rule 701 meets the requirements of 40 CFR 51.152(a)(1). 

Rule 701, paragraph C.2 requires the air pollution control officer (APCO) to notify the “[EPA], [ARB], 

news media, schools, medical facilities, child day care facilities and the general public when an episode 

is declared.” It also requires the APCO to maintain on-line access to monitoring data, to provide for online notification subscriptions, and to monitor air quality and disseminate information by phone, text 

messaging, the subscription service, and the air district’s website. Paragraph C.3 specifies the content of 

such notifications, which includes the stage level, the impacted area, the relevant pollutant, and an 

associated health message. Paragraph C.5 further requires that Stage 1 and 2 health advisories 

recommend protective measures to limit the public’s exposure, with Stage 2 recommendations being 

more stringent (e.g., eliminate outdoor activity vs. minimize outdoor activity). 

Paragraph C.6 requires that an episode be terminated when the pollutant concentration has been verified 

to have fallen below the episode criteria and is expected to continue to decrease. Finally, paragraph C.8 

provides a means for the APCO to respond to requests from an APCO of an adjoining air basin (e.g., 

San Joaquin Valley APCD) by evaluating the need for, and then directing, implementation of abatement 

actions. In sum, Rule 701 requires public announcement of a Stage 1 or 2 episode and communication 

procedures for notifying the public, news media, schools, medical facilities, and other governmental 

agencies, and provides mechanisms to terminate an episode and to coordinate action with nearby air 

districts. Thus, we propose to find that Rule 701 meets the requirements of 40 CFR 51.152(a)(2) and 

(b)(3). 

Regarding emission control actions, Rule 701, paragraph C.7 requires that, upon declaration of a 

predicted Stage 1 or 2 episode, that “all coinciding scheduled prescribed burning, shall be prohibited” 

and that upon declaration of a Stage 1 or 2 episode “all prescribed burning, if already ignited, shall be 

terminated.” In other words, when the APCO declares an emergency episode, Rule 701 provides a 

means to avoid or reduce PM emissions that would otherwise be produced by prescribed burns. More 

broadly, California’s 2014 Submittal states that BACM level controls are “already in place for most of 

the dried emissive areas [of the Owens Lake bed] to control the fugitive dust events.”39 Great Basin’s 

2014 TSD credits 45 square miles of such BACM controls as reducing by 90% the annual tons of 

potential PM10 emitted from the lake bed.40 The air district predicts further emission reductions if 

supplemental controls are fully implemented. However, the determination of how much area to control 

in successive years is a medium- to long-term process that is infeasible to implement in an emergency 

episode timeframe of hours or days. Unlike a classic emergency episode event where an APCO may 

require a major stationary source or companies with fleets of vehicles to curtail their emissions within 

hours, the controls applied to the lakebed such as flooding, vegetation, gravel application, etc. take 

months and years to fully implement. Thus, while the emission control actions of Rule 701 are limited, 

in this unique case such a limitation is reasonable given the dominance of PM emissions from the 

Owens Lake bed and surrounding dunes and the longer term efforts to resolve this air pollution problem. 

Thus, we propose to find that Rule 701 meets the requirements of 40 CFR 51.152(a)(3). 

 

39 California’s 2014 Submittal, Enclosure 1, p. 35. 

40 Great Basin’s 2014 TSD, p. 23. 
16 

Paragraph C.1 requires the APCO to maintain strategic, continuous air pollution monitors to predict and 

measure air pollution episodes and that the APCO use other sources of information such as “the National 

Weather Service, the Tribal Environmental Exchange Network, and the Incident Information System for 

episode notification and forecasting.” Paragraph C.2.d reinforces the continuous nature of this 

monitoring requirement. Lastly, paragraph C.9 requires the APCO to investigate the nature of the Stage 

1 or Stage 2 episode and “determine if abatement actions could be taken to reduce the pollution levels.” 

While such abatement is not required (beyond the abatement embodied by the prescribed burning 

provisions of paragraph C.7), this provides a regulatory basis for investigating the cause of such an 

emergency episode. Thus, Rule 701 provides for prompt acquisition of atmospheric conditions and 

inspection of sources and therefore meets the requirements of 40 CFR 51.152(b)(1) and (b)(2). 

On the merits of Great Basin Unified APCD Rule 701, we propose to find that Rule 701 meets the 

emergency episode planning requirements of CAA section 110(a)(2)(G) and 40 CFR part 51, subpart H 

for PM. 

San Joaquin Valley 

As noted above, we propose to revise the PM emergency episode classification of San Joaquin Valley 

AQCR from Priority I to Priority II. We reviewed the existing emergency episode contingency plan in 

the California SIP to determine if it is adequate for PM2.5, as California has not made any recent 

submittal for emergency episode planning for San Joaquin Valley. 

San Joaquin Valley’s emergency episode contingency plan, made up of multiple rules under Regulation 

6 (“Air Pollution Emergency Episodes”), was approved into the California SIP on March 18, 1999.41 We 

did not find provisions specific to PM2.5 within Regulation 6. Due to the 24-hour PM2.5 value of 167 

μg/m3recorded at the Bakersfield-Planz monitor, which is above the Priority II threshold for PM in 40 

CFR 51.150(d), we propose to conclude that the California SIP does not have an emergency episode 

contingency plan applicable to PM2.5 and therefore does not meet the requirements of CAA section 

110(a)(2)(G) and 40 CFR part 51, subpart H for PM. 

Emergency Episode Contingency Plans for 2008 Pb NAAQS

Additional Background 

EPA has not promulgated regulations to provide Pb ambient air quality levels on which to base formal 

classifications nor to establish an SHL. EPA’s 2011 Infrastructure SIP Guidance states that an 

emergency episode for Pb “would be unlikely and if it were to occur, would be a result of a malfunction 

or other emergency situation at a relatively large source of Pb. Accordingly, EPA believes the central 

components of a contingency plan would be to reduce emissions from the source at issue (if necessary 

by curtailing operations) and public communication as needed.”42 EPA’s 2011 Infrastructure SIP 

Guidance also notes that the provisions of 40 CFR part 51, subpart H and 40 CFR part 51, Appendix L 

do not apply to Pb but that states may wish to consult such provisions in developing their Pb emergency 

episode contingency plans. 

California’s response to this requirement 

California’s 2011 Submittal states that “California will use a lead concentration of 0.60 μg/m3averaged 

over a three-month period to define [an SHL for Pb]”, which is four times the NAAQS level of 0.15 

 

41 64 FR 13351, March 18, 1999. 

42 EPA’s 2011 Infrastructure SIP Guidance, p. 13. 
17 

μg/m3and is consistent with the model of SHLs for other NAAQS.43 It also asserts that monitoring data 

do not show concentrations approaching this level, except near large Pb-acid battery recycling facilities 

in the Los Angeles County Pb nonattainment area. For sources outside this area, the submittal states that 

the state’s authority to act is sufficient to implement an emergency response for Pb. For sources inside 

this nonattainment area, the South Coast air district adopted Rule 1420.1, “which applies to any large 

lead-acid battery recycling facility in the South Coast Air Basin that processes or has ever processed 

50,000 tons or more of lead per year.” California’s 2011 Submittal then states the following: 

Rule 1420.1 requires total enclosures for any process associated with the preparation, recovery, 

refining, and storage of lead-containing material and requires pollution control devices on the 

enclosures and on lead emission point sources. Rule 1420.1 also includes housekeeping, 

monitoring, and recordkeeping requirements. The trigger level specified in Rule 1420.1 is 0.15 

μg/m3 averaged over any consecutive 30-day period. In addition, as of July 1, 2011, any facility 

exceeding an ambient lead concentration of 0.12 μg/m3 averaged over any consecutive 30-day 

period must submit a Compliance Plan identifying additional lead emission reduction measures, 

thereby ensuring subsequent compliance with the federal lead standard. 

California’s 2014 Submittal requests that EPA treat the Los Angeles County Pb nonattainment area as a 

Priority I region for emergency episode planning and all other areas as Priority III.44

EPA’s evaluation 

We have reviewed the California’s 2011 and 2014 Submittals and find that California’s approach is 

acceptable in its focus on the Los Angeles County Pb nonattainment area and in the substance of its SIPapproved measure to address the sources therein of greatest concern for potential emergency episodes. 

In particular, we have evaluated South Coast Rule 1420.1 against the emergency episode contingency 

plan requirement of CAA section 110(a)(2)(G) with respect to the Los Angeles County Pb 

nonattainment area. 

California treatment of Pb as a toxic air contaminant 

Several rules by the South Coast air district provide context for how Pb emissions have been regulated 

prior to designation of the Los Angeles County nonattainment area for the 2008 Pb NAAQS. The 

California Office of Environmental Health Hazard Assessment (OEHHA) classifies Pb as a carcinogenic 

toxic air contaminant (TAC) and, as such, it is subject to California HSC Section 44362(a) requirements 

for air toxics.45 Consistent with these requirements, Pb is included in South Coast Rule 1401 list for 

TAC’s, and Rule 1401 specifies limits for the maximum individual cancer risk (MICR). 

South Coast Rule 1402 (“Control of Toxic Air Contaminants from Existing Sources”) was developed to 

reduce health risks associated with toxic air contaminants from existing sources by specifying limits for 

the MICR, cancer burden, and noncancerous acute and chronic hazard index (HI) applicable to total 

facility emissions. Rule 1402 requires facilities to implement risk reduction plans to achieve specific risk 

limits as required by the California Air Toxics “Hot Spots” Act and the rule itself. The rule also 

specifies public notification and inventory requirements. 

 

43 California’s 2011 Submittal, Appendix A, p. A-9. 

44 California’s 2014 Submittal, Enclosure 1, p. 34. 

45 California Air Pollution Control Officers Association (CAPCOA) Air Toxic Hot Spots Program Risk Assessment 

Guidelines, Appendix A-1 (“Substances for Which Emissions Must be Quantified”), approved by the California Office of 

Administrative Law on August 27, 2007, p. A-8. 
18 

South Coast Rule 1420 (“Emission Standards for Lead”) was adopted in 1992 to meet the 1978 Pb 

NAAQS of 1.5 μg/m3 measured on a quarterly basis. This rule applies to all facilities in South Coast air 

district that use or process Pb-containing materials. This rule addresses the now-revoked 1978 Pb 

NAAQS by requiring emission control systems, monitoring, and good housekeeping practices. Although 

this rule also applies to Pb-acid battery recycling facilities, South Coast air district found that it does not 

contain specific and adequate control measures for this source category to minimize Pb exposure 

consistent with the 2008 Pb NAAQS.46

Designation and regulation for the 2008 Pb NAAQS 

Pb concentrations throughout California, including most of Los Angeles County, are generally far below 

the 2008 Pb NAAQS.47 However, fence line monitors near Exide Technology’s large, Pb-acid battery 

facility in the city of Vernon exceeded the 2008 Pb NAAQS from February 2008 through January 

2010.48 Emissions from this facility are believed to be the sole contributor to Pb violations in the South 

Coast Air Basin. A portion of Los Angeles County was designated nonattainment for the 2008 Pb 

NAAQS on November 22, 2010 and it is the only Pb nonattainment area in California.49

South Coast Rule 1420.1 (“Emission Standards for Lead and other Toxic Air Contaminants from Large 

Lead-Acid Battery Recycling Facilities”) was adopted in November 2010. The purpose of this rule is to 

protect public health by reducing emissions of and exposure to Pb and to attain the 2008 Pb NAAQS. 

Compliance with Rule 1420.1 is primarily based on ambient concentration of Pb at fence line monitors. 

Beginning in July 2011, any facility exceeding an ambient air Pb concentration of 0.12 μg/m3 averaged 

over any consecutive 30-day period must submit a compliance plan. Specific compliance plan details are 

outlined in section (g) (“Compliance Plan”) of Rule 1420.1. The compliance plan must identify 

additional measures to be implemented if emissions exceed 0.15 μg/m3 averaged over any consecutive 

30-day period – the limit set in section (d)(2) of the rule. Rule 1420.1 requirements are more stringent 

than the 2008 Pb NAAQS because of, among other things, the shorter averaging time. 

We have determined that feedstock reductions, outlined in Table 1 of Rule 1420.1, and the requirements 

in section (d) (“General Requirements”), which prohibit discharges of Pb resulting in fence line 

concentrations above 0.15 μg/m3averaged over any 30 consecutive day period, are adequate to prevent 

ambient Pb concentrations from reaching California’s proposed SHL of 0.60 μg/m3averaged over a 3-

month period. EPA has also approved California’s attainment plan for the Los Angeles County Pb 

nonattainment area, whose control strategy relies primarily on Rule 1420.1 to meet the 2008 Pb 

NAAQS.50 Numerous violations of the 0.15 μg/m3threshold in Rule 1420.1 by Exide Technology’s Pbacid battery facility have been recorded at the facility’s fence line. Since its adoption, Rule 1420.1 has 

been the basis of enforcement actions against the facility by South Coast air district51 and, since its 

inclusion in the California SIP, by EPA.52

 

46 South Coast Air Quality Management District (AQMD) Staff Report Proposed Rule 1420.1 (“Emissions Standard for Lead 

from Large Lead-Acid Battery Recycling Facilities”), November 2010, p. 1-1. 

47 See Appendix E to this TSD for 2013 and partial 2014 Pb data for Los Angeles County. 

48 South Coast AQMD Staff Report Proposed Rule 1420.1 (“Emissions Standard for Lead from Large Lead-Acid Battery 

Recycling Facilities”), November 2010, p. 1-7. 

49 75 FR 71033, November 22, 2010. 

50 79 FR 13875, March 12, 2014. 

51 See South Coast air district’s website regarding compliance with Rule 1420.1 at 

http://www.aqmd.gov/home/regulations/compliance/exide-updates/compliance-permitting-toxics. 

52 See EPA’s “Finding and Notice of Violation in the Matter of: Exide Technologies, Vernon, California, Proceeding under 

Section 113(a), Clean Air Act, As Amended,” Docket No. R9-2014-05, May 22, 2014. 
19 

Section (n) (“Reporting”) of Rule 1420.1 outlines public notification requirements. Per section (n)(1) of 

the rule, the facility shall report any exceedance of the ambient air Pb concentrations specified in the 

rule with a notification to 1-800-CUT-SMOG followed by a written report to the South Coast air district 

Executive Officer within three days of such notification. Section (n)(2) specifies the additional 

conditions pertaining to public notification as follows: 

· (n)(2)(A) Notify the Executive Officer and the public within one hour after an unplanned shut 

down. 

· (n)(2)(B) Notify the Executive Office and the public at least ten calendar days prior to a planned 

turnaround or shutdown of equipment specified in the rule. 

· (n)(2)(D) Notify the public at least ten calendar days prior to the beginning of building 

construction, renovation, demolition and other construction or maintenance activities specified in 

the rule. 

· (n)(2)(F) Notification to the public for the three scenarios above must be provided “through a 

facility contact or pre-recorded notification center that is accessible that is accessible 24 hours a 

day, 7 days a week, and through electronic mail using a list of recipients provided by the 

Executive Officer.” 

In addition, section (n)(2)(G) requires the facility to install a sign that is visible to the public and 

displays a phone number for the facility contact or the pre-recorded notification center. 

As stated above, EPA’s 2011 and 2013 Infrastructure SIP Guidance suggests that, in absence of a SHL, 

the central components of a contingency plan would be to reduce emissions if necessary by curtailing 

operations, and public communication as needed. South Coast air district Rule 1420.1 incorporates 

stringent control measures and emergency actions including emissions curtailment and public 

notification necessary to protect public health with respect to Pb. Rule 1420.1 adequately serves to 

minimize the likelihood of exceeding the 2008 Pb NAAQS and to prevent ambient Pb concentrations 

from reaching the SHL identified in California’s 2014 Submittal. EPA approved November 2010 

version of Rule 1420.1 into the SIP on January 25, 2013.53 Therefore, we propose to find that the 

California SIP meets the requirements of CAA section 110(a)(2)(G) with respect to Pb. 

Future recommendations 

Rule 1420.1 was amended in January and March of 2014, but the amendments have not been submitted 

to EPA for SIP approval. While not critical for EPA approval of California’s 2011 and 2014 Submittals, 

we recommend that CARB submit the latest version of Rule 1420.1 to EPA for incorporation into the 

California SIP. Such a SIP revision could also explain if or how Rule 1420.1 acts in concert with South 

Coast Regulation 7 (“Air Pollution Emergency Contingency Actions”), which EPA approved into the 

California SIP on March 25, 1999.54

Emergency Episode Contingency Plans for 2010 NO2 NAAQS

California’s response to this requirement 

California’s 2012 Submittal states that annual average concentrations of NO2 range from 1 to 25 ppb, 

which is well below the Priority I classification threshold of 60 ppb, and therefore no area of the state is 

required to have an NO2 emergency episode contingency plan.55 The submittal notes that the 

Metropolitan Los Angeles AQCR was historically classified as the sole Priority I area in California, 

 

53 78 FR 5305, January 25, 2013. 

54 64 FR 14391, March 25, 1999. 

55 California’s 2012 Submittal, Enclosure 1, p. A-10. 
20 

having annual average concentrations up to 94 ppb in the 1970s. The area was also formerly designated 

nonattainment for the 1971 NO2 NAAQS. In light of the significant decrease in NO2 concentrations 

since the 1970s ARB requests that, for the Metropolitan Los Angeles, EPA either exempt the region 

from the emergency episode contingency plan requirement, as provided under 40 CFR 51.152(d)(1), or 

reclassify the region to Priority III.56

California’s 2014 Submittal reiterates the themes of California’s 2012 Submittal with respect to NO2

emergency episode planning, and asserts that the SHL for NO2 (1-hour: 2.0 ppm; 24-hour: 0.5 ppm) 

hasn’t been reached in decades. It also narrows the request for Metropolitan Los Angeles to one of 

reclassification to Priority III, rather than one of exemption or reclassification. 

EPA’s evaluation 

EPA evaluated whether to grant or deny the reclassification request made by ARB, consistent with the 

requirements of 40 CFR part 51, subpart H. As described above for ozone, the test for classifying 

AQCRs is prescribed in 40 CFR 51.150(b) and should use the most recent three years of data, consistent 

with 40 CFR 51.153. For NO2, an AQCR with an annual average NO2 level greater than 0.06 ppm must 

be classified Priority I. 

Accordingly, we have reviewed California’s 2011-2013 air quality data for the three air districts that 

comprise portions of the Metropolitan Los Angeles (i.e., Santa Barbara County, South Coast, and 

Ventura County).57 The highest annual average NO2 concentration was 25.27 ppb – well below the 

Priority I threshold, as noted by ARB. Thus, we propose to grant the reclassification of Metropolitan Los 

Angeles to Priority III for NO2. Upon finalization of the reclassification, Metropolitan Los Angeles 

AQCR, including the Ventura County air district and the relevant portions of the Santa Barbara County 

and South Coast air districts, would no longer be required to have an emergency episode contingency 

plan (e.g., episode criteria) for NO2, though each air district would need to retain such plans to the extent 

they address the contingency plan requirement for ozone, as discussed above. 

We agree with California’s 2012 Submittal that upon such reclassification, the whole state will be 

classified Priority III, and therefore no emergency episode contingency plan for NO2 would be required 

for any of the state’s 14 AQCRs. In brief, we propose to find that California’s 2012 and 2014 Submittals 

meet the contingency plan requirement of CAA section 110(a)(2)(G) for NO2. 

Emergency Episode Contingency Plans for 2010 SO2 NAAQS

California’s response to this requirement 

As noted for ozone and NO2, California’s 2014 Submittal states that California’s SOx concentrations 

have decreased substantially, have not reached the SHL for SO2 (24-hour SO2: 1.0 ppm) in decades, and 

are now better than the Priority II classification thresholds. The submittal notes that California’s AQCRs 

were originally classified either Priority II (including the Metropolitan Los Angeles and San Francisco 

Bay Area AQCRs) or Priority III.58

It then states that ARB recommended that all of California be designated as attainment for the 2010 1-

hour SO2 NAAQS, that EPA has not yet designated any area of California for this NAAQS, and that the 

state’s 33 SO2 monitors show attainment of the NAAQS. The submittal asserts that the maximum 1-hour 

 

56 Id, p. A-11. 

57 See Appendix F to this TSD. 

58 California’s 2014 Submittal, Enclosure 1, p. 32. 
21 

SO2 concentration during 2010 through 2012 was 0.073 ppm, which is well below the 3-hour and 24-

hour thresholds for classification as Priority II. Similarly, it states that California has attained the 1971 

annual SO2 standard of 0.03 ppm since the 1980s. Therefore, ARB requests that EPA reclassify the 

Metropolitan Los Angeles and San Francisco Bay Area AQCRs to Priority III for SO2, thereby relieving 

the requirement for an emergency episode contingency plan. 

EPA’s evaluation 

As with ozone and NO2, EPA evaluated whether to grant or deny the reclassification request made by 

ARB, consistent with the requirements of 40 CFR part 51, subpart H. The classification thresholds for 

SO2 are unique in that thresholds are prescribed for three different averaging periods. The thresholds and 

ranges for Priority II classification are as follows: 

· 3-hour: greater than 0.5 ppm, 

· 24-hour: 0.10 – 0.17 ppm, and 

· Annual arithmetic mean: 0.02 – 0.04 ppm. 

Accordingly, we have reviewed California’s 2011-2013 air quality data for the three air districts that 

comprise portions of the Metropolitan Los Angeles AQCR (i.e., Santa Barbara County, South Coast, and 

Ventura County) and the Bay Area AQMD, which covers the entirety of the San Francisco Bay Area 

AQCR.59 The highest SO2 levels in Metropolitan Los Angeles were 24.3 ppb for the 24-hour average 

and 1.99 ppb for the annual arithmetic mean. The highest SO2 levels in San Francisco Bay Area were 

8.1 ppb the 24-hour average and 3.26 ppb for the annual arithmetic mean. In addition, the highest 1-hour 

SO2 concentrations during this period were 85.5 ppb in Metropolitan Los Angeles and 68.1 ppb in San 

Francisco Bay Area.60 While there are no 1-hour SO2 classification thresholds in 40 CFR 51.150(b), by 

definition these concentrations reinforce the fact that 3-hour and 24-hour levels have not exceeded the 

respective Priority II classification thresholds because they are lower than such thresholds. 

Thus, we propose to grant the reclassification of the Metropolitan Los Angeles and San Francisco Bay 

Area AQCRs to Priority III for SO2. Upon finalization of the reclassification, Metropolitan Los Angeles 

AQCR, including the Ventura County air district and the relevant portions of the Santa Barbara County 

and South Coast air districts, would no longer be required to have an emergency episode contingency 

plan (e.g., episode criteria) for SO2, though each air district would need to retain such plans to the extent 

they address the contingency plan requirement for ozone, as discussed above. We agree with 

California’s 2014 Submittal that upon such reclassification, the whole state will be Priority III, and 

therefore no emergency episode contingency plan for SO2 would be required for any of the state’s 14 

AQCRs. In brief, we propose to find that California’s 2014 Submittal meets the contingency plan 

requirement of CAA section 110(a)(2)(G) for SO2. 

 

59 See Appendix G.1 (for Metro Los Angeles) and G.2 (for San Francisco Bay Area) to this TSD. 

60 Appendix G.1 includes a 1-hour SO2 concentration of 117.0 ppb in Lompoc, Santa Barbara County. However, this monitor 

is located outside the Metropolitan Los Angeles AQCR (i.e., the southern, coastal portion of Santa Barbara County) and is 

therefore irrelevant to the classification of Metropolitan Los Angeles. It was included for simplicity of pulling the data from 

the Air Quality System database. Also, this concentration does not make the South Central Coast AQCR, which includes San 

Luis Obispo County and a portion of Santa Barbara County, a Priority II area because the 2nd highest 1-hour SO2 level for the 

same year was 5.0 ppb, resulting in 3-hour, 24-hour, and annual averages well below the respective Priority II classification 

thresholds for SOx.