Adequacy Status of 8-hour Ozone and PM2.5 Motor Vehicle 

Emissions Budgets in 2007 South Coast State Implementation 

Plan 

 We have found adequate for transportation conformity 

purposes certain 8-hour ozone and PM2.5 motor vehicle 

emissions budgets in the 2007 South Coast State 

Implementation Plan (2007 South Coast SIP), as amended on 

April 30, 2008. As a result of our adequacy findings, the 

Southern California Association of Governments (SCAG) and 

the U.S. Department of Transportation must use the adequate 

budgets in future transportation conformity determinations 

once the findings become effective. 

 By letter dated November 28, 2007, the California Air 

Resources Board (CARB) submitted the 2007 South Coast SIP 

to EPA as revisions to the California State Implementation 

Plan. On February 1, 2008, CARB submitted supplemental 

technical information related to RFP for the 8-hour ozone 

NAAQS. On February 12, 2008, we announced receipt of the 

plans on the Internet and requested public comment by March 

13, 2008. We received one set of public comments from 

Coalition for Clean Air, Earthjustice, and Natural 

Resources Defense Council. Our responses to these comments 

are contained in an attachment to this letter. 

On March 25, 2008, CARB proposed revisions to the 8-

hour ozone and PM2.5 motor vehicle emissions budgets in the 

2007 South Coast SIP and posted these revised budgets on 

its website. In its March 26, 2008 letter to EPA, CARB 

indicated that the proposed motor vehicle emissions budgets 

would replace the motor vehicle emissions budgets in the 

2007 South Coast SIP and requested that EPA parallel 

process its adequacy review of the revised motor vehicle 

emissions budgets. On March 27, 2008, we announced our 

adequacy review of the revised budgets and requested public 

comment by April 28, 2008. CARB adopted the budgets as 

proposed, and submitted them to EPA on April 30, 2008. We 

received one set of comments during the second comment 

period from Robert E. Yuhnke, Adrian Martinez, and Michael 

Replogle (representing the Coalition for Clean Air,

Coalition for a Safe Environment, Endangered Habitats 

League, Environmental Defense Fund, East Yard Communities 

for Environmental Justice, and the Natural Resources 
2

Defense Council). Our responses to these comments are 

contained in the enclosure. 

 Through its April 30, 2008 submittal, CARB has 

replaced the original set of motor vehicle emissions 

budgets in the 2007 South Coast SIP with two sets of motor 

vehicle emissions budgets, referred to as “SIP-based” 

budgets and “baseline” budgets. CARB states that the “SIPbased” budgets are consistent with the 8-hour ozone and 

PM2.5 attainment and reasonable further progress 

demonstrations submitted to EPA on November 28, 2007, but 

are not identical to the original motor vehicle emissions 

budgets in the 2007 South Coast SIP. The “SIP-based” motor 

vehicle emissions budgets differ from the original budgets 

in two ways. First, emissions reductions attributable to 

the State’s strategy have been removed from the 2008 8-hour 

SIP’s ozone motor vehicle emissions budgets and the 2009 

PM2.5 SIP’s motor vehicle emissions budgets. Second, the

budgets, originally calculated using the South Coast Air 

Quality Management District’s CEPA emission factor model, 

were re-calculated using EMFAC2007. EPA approved the 

EMFAC2007 model for SIP and conformity purposes on January 

18, 2008 (73 FR 3464); EPA has not approved CEPA for SIP 

development or transportation conformity analyses. 

The “baseline” motor vehicle emissions budgets reflect 

emissions reductions from rules that were adopted as of 

October 2006 but, in contrast to the “SIP-based” budgets, 

do not include new emissions reductions from the State’s 

strategy as reflected in the 2007 South Coast SIP. The 

“baseline” motor vehicle emissions budgets are also based 

on EMFAC2007. 

The State requests that EPA gives primary 

consideration to the “SIP-based” budgets in its adequacy 

review, and only find the “baseline” budgets to be adequate 

if EPA cannot find the “SIP-based” budgets adequate in 

their entirety. Both sets of motor vehicle emissions 

budgets, as submitted on April 30, 2008, are shown in the 

following tables: 

“Baseline” 8-hour Ozone Motor Vehicle Emissions Budgets

8-hour ozone – summer average tons per day 

(tpd)

Budget Year

ROG NOx
3

“Baseline” 8-hour Ozone Motor Vehicle Emissions Budgets

2008 215 427 

2011 176 354 

2014 150 287 

2017 131 232 

2020 116 190 

“Baseline” PM2.5 Motor Vehicle Emissions Budgets

Budget Year PM2.5 – annual average tons per day (tpd)

ROG NOx PM2.5

2009 196 413 38 

2012 163 337 38 

“SIP-based” 8-hour Ozone Motor Vehicle Emissions Budgets

8-hour ozone – summer average tons per day

(tpd)

Budget Year

ROG NOx

2008 215 427 

2011 162 320 

2014 125 196 

2017 111 167 

2020 101 145 

2023 93 128 

“SIP-based” PM2.5 Motor Vehicle Emissions Budgets

Budget Year PM2.5 – annual average tons per day (tpd)

ROG NOx PM2.5

2009 196 413 38 

2012 139 276 37 

2014 122 201 33 

2023 89 131 37 

2030 75 121 39 
4

 This transmits our decision that the 8-hour ozone and 

PM2.5 reasonable further progress “baseline” motor vehicle 

emissions budgets in the 2007 South Coast SIP, as amended 

on April 30, 2008, are adequate for transportation 

conformity purposes. These “baseline” budgets are 

consistent with the State’s reasonable further progress 

demonstrations for 8-hour ozone and PM2.5, and these budgets 

are based adopted control measures that have already been 

implemented. The budgets also meet the other adequacy 

criteria, including being precisely quantified and clearly 

related to the overall SIP. Therefore, these budgets meet 

the transportation conformity adequacy criteria found in 40 

CFR 93.118(e)(4). 

This also transmits our finding that the 8-hour ozone 

and PM2.5 “SIP-based” motor vehicle emissions budgets in the

2007 South Coast SIP are inadequate for transportation 

conformity purposes. The “SIP-based” budgets include 

estimated emission reductions associated with a number of 

commitments for future rule adoption that lack specificity. 

As such, SCAG will not be able to accurately quantify 

future emission reductions associated with the commitments. 

Without additional specificity, it is also unclear how the 

“SIP-based” budgets are precisely quantified or related to 

the overall emissions inventory and other measures.

Therefore, these “SIP-based” budgets do not meet the 

adequacy criteria found in 40 CFR 93.118(e)(4). 

We have detailed our findings in additional enclosure. 

A copy of the transmittal letter, this, and the transmittal 

letter’s other enclosures will soon be posted on the 

Internet at 

http://www.epa.gov/otaq/stateresources/transconf/adequacy.h

tm. We will also announce the findings of adequacy and 

inadequacy in the Federal Register. The findings will 

become effective 15 days after the Federal Register

announcement pursuant to 40 CFR 93.118(f). 

 
Enclosure 1 

Transportation Conformity Adequacy Review 

2007 South Coast SIP [Reasonable Further Progress (RFP) and Attainment Demo

8-Hour Ozone and PM2.5] 

Adopted September 27, 2007 (2007 South Coast SIP), November 15, 2007 (original motor vehic

(revised motor vehicle budgets); Submitted November 28, 2007 (2007 South Coast SIP, inc

February 1, 2008 (supplemental material related to eight-hour ozone RFP), April 30, 200

budgets). 

Adequacy Review Criteria 

(40 CFR part 93) 

Is 

Criterion 

Satisfied? 

Reference in SIP document/commen

Sec. 93.118(e)(4)(i) 

The plan was endorsed by the Governor (or designee) and was subject to a public hearing by the State. 

Y The November 28, 2007 transmittal letter submitting the 2007 So

original budgets was sent by CARB’s Executive Officer, James G

designee. CARB held a public hearing on September 27, 2007 on 15, 2007 on the original motor vehicle emissions budgets. The Asubmitting the revised motor vehicle emissions budgets was sent Officer, James Goldstene, the governor’s designee. CARB held a 2008 on the revised motor vehicle emissions budgets. 

Sec. 93.118(e)(4)(ii) 

The plan was developed through consultation with federal, state and local agencies; full implementation plan documentation was provided to EPA and EPA’s stated 

Y Documentation accompanying the plan describes a public and ag

e.g., the SCAQMD’s Response to Comments on the Draft 2007 A(February 2007), submitted by CARB on November 28, 2007 as regional workshops held from October 24 through December 6, 2Air Quality Management Plan (AQMP) released on October 10, meetings held to discuss the elements of the draft State Strategy (State Strategy) is described in the CARB staff report developed consideration prior to adoption of the State Strategy. The State SSeptember 27, 2007, and submitted to EPA on November 28, 20South Coast SIP. EPA received a copy of the draft 2007 AQMP 

EPA’s comments were addressed. The revised motor vehicle em
concerns, if any, were addressed. 

CARB on April 24, 2008, and submitted to EPA on April 30, 200consultation process, in which EPA’s comments on the draft revibudgets were addressed. 

Sec. 93.118(e)(4)(iii) 

The motor vehicle emission budgets are clearly identified and precisely quantified. 

Y/N Both the “SIP-based” and “baseline” budgets are clearly identifie

the following website: http://www.arb.ca.gov/planning/sip/sip.ht

down the page at the section titled “2007 South Coast and CoachPM2.5 Plans” (Attachments 1 and 2). The “SIP-based” budgets ar

because the new emission reductions do not result from adequateIn contrast, the “baseline” budgets reflect control measures that ado not include new emission reductions attributed to general combudgets are precisely quantified. 

Sec. 93.118(e)(4)(iv) 

The motor vehicle emissions budgets, when considered together with all other emission sources, are consistent with applicable requirements for reasonable further progress, attainment, or maintenance (whichever is relevant to the given plan). 

Y/N EPA has preliminarily concluded that the “baseline” budgets, wh

all other emission sources, are consistent with the requirement to 

further progress for eight-hour ozone (years 2008, 2011, 2014, 2

(years 2009 and 2012). With respect to ozone, this finding is basozone RFP demonstration, as supplemented on February 1, 2008the required 3% annual rate of progress (averaged over each threEPA’s eight-hour ozone implementation rule. With respect to PM

review of the State’s RFP modeled demonstration that reasonably 

attainment targets and thus establishes approximate levels of emiachieve generally linear progress for the 2009 and 2012 PM2.5 RF

EPA’s PM2.5 Implementation Rule. EPA cannot determine that th

emissions budgets are consistent with the requirement to demonsbased” motor vehicle emissions budgets incorporate new emissiofrom specified control measures that have been drafted or adoptebeen adequately supported as a voluntary measure). 

Sec. 93.118(e)(4)(v) 

The plan shows a clear relationship between the emissions budgets, 

Y/N The emission inventories for all point, area, and mobile sources f

2023 are contained in Chapter 3 of SCAQMD’s Final 2007 Air Q

(AQMP). The control strategy that is relied upon for the “SIP-baChapter 4 of SCAQMD’s Final 2007 AQMP and Appendix IV-A
control measures and the total emissions inventory. 

(http://www.arb.ca.gov/planning/sip/2007sip/southcoast/scstaffre

The tables on pages ES-3 and ES-4 of the CARB Staff Report prsource emission reductions for PM2.5 and 8-hour ozone, respectiv

CARB submitted supplemental information concerning 8-hour osupplemented on February 1, 2008, shows a clear relationship beand the emissions inventory, but does not show a clear relationshemissions budgets, control measures, and the total emissions invApril 30, 2008 made changes to the budgets to reflect the use of (relative to those calculated using SCAQMD’s CEPA model) are estimates remain consistent with the RFP demonstrations for 8-h

2007 South Coast SIP, as supplemented for 8-hour ozone RFP on model” adjustments to the baseline inventory, as referenced in thvehicle emissions budgets, for the motor vehicle emission budge(NOx), 76 (ROG) and 79 (PM2.5) of Appendix A, the Emission I

the May 7, 2007 update to the Revised Statewide Strategy for Cathe document can be found at: http://www.arb.ca.gov/planning/sip/2007sip/2007sip.htmThe doc

http://www.arb.ca.gov/planning/sip/2007sip/apr07draft/revdrftap

associated with the following rules adopted through December 3Fleets, Idling, AB1493, and the Carl Moyer Program. The emissiwith the Carl Moyer Program have been adjusted by 47% to reflereductions from Moyer programs. As stated elsewhere, the “SIP-emissions budgets incorporate new emission reductions from the result from specified control measures that have been drafted or 

have been adequately supported as a voluntary measure). 

Sec. 93.118(e)(4)(vi) 

Revisions to previously submitted control strategy or maintenance plans explain and 

Y The budgets found adequate in this action constitute a revision to 

on November 28, 2007. The revision, submitted on April 30, 200

changes to previously submitted budgets. 
document any changes to any previous submitted budgets and control measures; impacts on point and area source emissions; any changes to established safety margins (see 93.101 for definition), and reasons for the changes (including the basis for any changes to emission factors or estimates of vehicle miles traveled). 

Sec. 93.118(e)(5) 

EPA has reviewed the State’s compilation of public comments and response to comments that are required to be submitted with any implementation plan. 

Y SCAQMD compiled public comments submitted during the June 

during the public comment periods. These comments and the resFebruary 2007 “Response to Comments” (http://www.aqmd.gov/aqmp/07aqmp/modified/Response_to_Copublic comments submitted during the September 27, 2007, Nov24, 2008 public hearings and during the public comment periodsresponses are included in adoption hearing transcripts (http://www.arb.ca.gov/board/meetings.htm). We have reviewed and responses and find SCAQMD’s and CARB’s responses to be might have affected our adequacy findings remain unanswered. 

Reviewer: Rebecca Rosen Date of Review: May 6, 2008
1

Enclosure 2 

Response to Comments 

Response to Comments from Coalition for Clean Air, Earth 

Justice, and Natural Resources Defense Council (Received: March 

13, 2008)

Comment 1: The commenter requests that EPA deny approval of the 

budgets on the basis that the emissions budgets are built on the 

foundation of an unapprovable SIP. The commenter further notes 

that their comments on the deficiencies in the budgets also 

highlight several areas where California’s 2007 State 

Implementation Plan (SIP) does not comply with the minimum 

requirements of the Clean Air Act. 

Response 1: EPA appreciates the above comments and will consider 

all comments relevant to SIP approvability at the time of its 

comprehensive review of the SIP. EPA has considered all issues 

in the SIP that are relevant to its budget adequacy decision, 

and has determined the “SIP-based” budgets (except for the 2008 

8-hour ozone and the 2009 PM2.5 budgets) to be inadequate 

pursuant to 40 CFR 93.118(e). In contrast, the “baseline” 

budgets are consistent with the State’s reasonable further 

progress demonstrations for 8-hour ozone and PM2.5, and these 

budgets are based on adopted control measures that have already 

been implemented. The budgets also meet the other adequacy 

criteria, including being precisely quantified and clearly 

related to the overall SIP. Therefore, these budgets meet the 

transportation conformity adequacy criteria found in 40 CFR 

93.118(e)(4). 

Comment 2: The commenter asserts that the budgets must be 

adjusted to exclude benefits of the federal motor vehicle 

control program. The commenter notes that the revised reasonable 

further progress (RFP) demonstration submitted by the SCAQMD 

purports to include some credit for the federal program, but 

that the budgets have not been, and must be, revised to reflect 

these changes to the RFP demonstration. 

Response 2: EPA understands this comment to pertain only to 8-

hour ozone Reasonable Further Progress. Additional information 

provided by the state demonstrates that RFP for South Coast is 

met after adjusting for the non-creditable emission reductions 

from the pre-1990 California Motor Vehicle Control Program 

(MVCP) as required under section 182(b)(2)(D). The MVCP 

benefits are deducted from the total baseline emission inventory 
2

and not the conformity budgets themselves. The additional 

information was provided to EPA by the State on February 1, 2008 

and made available to the public through EPA’s adequacy posting 

on March 27, 2008. EPA has made a preliminary review of this 

information to support its adequacy finding today. Further 

details regarding the specifics of the RFP demonstration are 

outside the scope of the adequacy process, and would be 

considered during EPA’s SIP review. 

Comment 3: The commenter asserts that the budgets should be 

adjusted to reflect the unenforceability of marine vessel 

controls given that the Pacific Merchant Shipping Association 

succeeded in PMSA v. Goldstene, No. 07-16695 (9th Cir. 2008) 

challenging CARB’s Auxiliary Engine Rule and thereby undermining 

the basis for the associated SOx emissions reductions included 

in the emissions budgets for the South Coast. The commenter also 

has concerns about certain emissions reductions claimed in the 

plan, including the 10 tpd of NOx emissions reductions in 2014 

from EPA controls on locomotives. If the Federal emissions 

reductions are uncertain, then the commenter believes that the 

budgets cannot assume them. 

Response 3: The first part of the comment is outside the scope 

of EPA’s adequacy review. The State did not establish SO2 motor 

vehicle emissions budgets in its PM2.5 SIP, since on-road SO2

emissions are not a significant source of emissions for the PM2.5

attainment demonstration. Therefore, the comment related to the 

9

th Circuit court decision on marine vessel control measures is 

not relevant to EPA’s adequacy review. EPA will consider this 

comment, as appropriate, during its review of the State’s PM2.5

attainment demonstration. 

Second, EPA is finding the 2014 PM2.5 motor vehicle emissions 

budget inadequate for transportation conformity purposes, in 

part because CARB relies on additional locomotive NOx reductions 

from federal rules to demonstrate PM2.5 attainment in 2014. On 

March 13, 2008, the EPA adopted standards to reduce emissions of 

diesel particulate matter and NOx from locomotives and marine 

diesel engines. Although EPA’s 2008 final rule establishes new 

emissions standards for locomotives and marine diesel emissions 

that will require aftertreatment devices for marine vessels, the 

final rule does not require that the implementation of these 

controls occur in the timeframe necessary to meet the 10 tpd of 

NOx emissions reductions assumed by CARB in the South Coast PM2.5

attainment demonstration for the year 2014. 
3

Comment 4: The commenter is also concerned about the inclusion 

of emissions reductions for the Refinery Pilot Program. 

Response 4: This comment is outside the scope of EPA’s adequacy

review. We appreciate the comments relating to the pilot 

program and we will examine, when we take rulemaking action on 

the plan, issues relating to the assignment of emission 

reductions to this measure. However, we believe that neither the 

RFP provisions nor the motor vehicle emissions budgets that we 

are finding adequate depend upon emissions reductions from the 

pilot program. 

Comment 5: The commenter asserts that California’s proposed use 

of “black box” measures in the 2007 SIP fails to meet the 

requirements and intent of the Clean Air Act. The commenter 

identifies three fundamental problems with the way California is 

using this allowance in the Clean Air Act: the magnitude of the 

black box (approximately 280 tons per day or 55% of the 

reductions needed from measures that still need to be adopted to 

attain federal air quality standards), the misuse of the “black 

box” to delay implementation of necessary and available measures 

needed from vehicle retirement, and the vagueness of the black 

box measures. In addition, the commenter believes that EPA 

should take into account the expected failure to attain the 1-

hour ozone standard by applicable attainment date of 2010 and 

the purported lack of success by the State with respect to 

“black box” measures in previously-approved 1-hour ozone plans 

in reviewing the “black box” commitments in the current plan 

submittal. In sum, the commenter believes that EPA must direct 

CARB to extract from the black box needed reductions they know 

will not come from future technologies, reduce the overall size 

of the black box to a reasonable level, and better define where 

the remaining black box reductions are expected to come from. 

Response 5: This comment is outside the scope of EPA’s adequacy

review. EPA will consider these comments and the issues they 

raise when we take rulemaking action on the 8-hour ozone 

attainment demonstration for 2023. The question of whether the 

"black box" portion of the plan is approvable affects only the 

adequacy of the attainment year budgets, since the plan does not 

rely on "black box" measure reductions for RFP. As discussed 

elsewhere, we are determining that the 8-hour ozone attainment 

year budgets in the “SIP-based” budgets are inadequate for 

reasons documented elsewhere in EPA’s adequacy finding. Please 

refer to other parts of today’s finding for further information. 
4

Comment 6: The commenter asserts that the control measures in

the plan fail to satisfy the minimum CAA requirements. Commenter 

asserts that many of the control measures in California’s SIP 

submittal must, but fail to, include the following elements, 

which commenter has compiled citing various EPA documents: 

(1) evidence of adoption of the measures in legally 

enforceable form or a binding schedule for adoption; 

(2) a description of each measure with “detail and

clarity,” identifying which entity is responsible for 

implementation and what “actions are to be taken;” 

(3) a “thorough demonstrate[ion] that the measures are 

capable of achieving the estimated emission reduction 

benefits;”

(4) an emission reduction estimate for each measure; 

(5) provisions for monitoring and reporting on 

implementation and effectiveness; and 

(6) an “identification of and commitment to the financial 

and manpower resources necessary to carry out the 

plan.” 

Response 6: EPA has found the motor vehicle emissions budgets 

that include new emissions reductions from the general 

commitments submitted in the 8-hour ozone and PM2.5 SIP to be 

inadequate for transportation conformity purposes. EPA has 

determined that these budgets are inadequate because these motor 

vehicle emissions budgets do not meet the adequacy criteria in 

40 CFR 93.118(e)(4)(iii), (iv) and (v), as described elsewhere 

in today’s finding. EPA will consider the comments on the 

control measures at the time that we review the SIP’s attainment 

demonstration for PM2.5 nonattainment areas and 8-hour ozone 

extreme areas. 

Comment 7: The commenter states that EPA must require CARB and

the SCAQMD to include new measures and strengthen existing 

measures to achieve additional reductions. The commenter asserts 

that the 2007 SIP does not include all feasible measures, and 

that several of the measures in the plan must be strengthened to 

achieve additional emissions reductions. Moreover, the commenter 

asserts that CARB continues to rely on more polluting diesel 

technologies rather than requiring the use of cleaner 

technologies and fuels to reach attainment sooner. 

The commenter lists and describes nine new or revised measures 

that EPA should require CARB to pursue, including: 

(1) cleaner in-use off-road equipment; 

(2) cleaner in-use heavy duty truck rule; 
5

(3) smog check improvements, particularly related to accurate 

SIP accounting for the failure rates for vehicles shortly 

after being repaired for emissions problems and/or 

passing smog check, accelerating the use of remote 

monitoring of OBD systems to ensure that vehicle owners 

fix faulty emissions systems, and expanding the testing 

program to include PM; 

(4) commitment to developing an in-use monitoring emissions 

standard for PM for heavy-duty vehicles; 

(5) expanded proposal related to passenger vehicle retirement 

above and beyond natural fleet turnover; 

(6) improved measure related to consumer products in relation 

to magnitude, specificity, and apparent reliance on a 

relative reactivity approach; 

(7) expanded commitment to create emission standards for 

recreational boats to include lower limits for ROG and 

NOx, a tighter implementation schedule, and inclusion of 

evaporative emission limits; 

(8) better use of the SIP development and approval process to 

achieve synergies with State programs related to 

climate, lower carbon fuels, and advanced clean vehicles 

to achieve the greatest pollution reductions; and 

(9) improved commitment for off-road mobile agricultural 

equipment to address enforceability concerns. 

With respect to the South Coast AQMD, the commenter lists and 

describes five new or revised measures, including: 

(1) certification and emission reductions from use of 

consumer products at institutional and commercial 

facilities, including such elements as tracking largevolume use of VOC emitting consumer products, developing 

and publicizing an inventory of the least VOC-forming 

cleaning products available in the market, and greatly 

accelerating the evaluation and certification of low- and 

non-polluting alternatives; 

(2) extended exchange program, including specific provisions 

as they relate to recreational boats within the SORE 

exchange program. 

(3) backstop measure for indirect source of emissions from 

ports and port-related facilities; 

(4) strengthened AB 923 light- and medium-duty vehicle highemitter identification programs to include heavier 

vehicles, address particulate emissions, prioritize

assistance to lower income participants, and increase 

public disclosure of the programs performance; and 

(5) tighter, and better defined, timeline for to achieve 

further SOx reductions for RECLAIM. 
6

Response 7: EPA appreciates the commenters’ thorough comments on 

specific control measures included in the SIP by CARB and 

SCAQMD, and will further consider these comments during its SIP 

review. EPA has considered whether the SIP demonstrates 

attainment for PM2.5 or 8-hour ozone for purposes of its adequacy 

review of the SIP-based budgets. In taking action on the plan, 

EPA will consider whether any additional commitments would 

expedite attainment for these pollutants as well as other 

details related to the new commitments in the SIP (other than 

on-road mobile commitments). The budgets that we are finding 

adequate at this time are only those associated with the 

baseline emissions for RFP milestones, and neither the RFP 

provisions nor these motor vehicle emissions budgets depend upon 

new emissions reductions from the stationary, non-road, or area 

source commitments described in the above comment. 

EPA will further consider the above comments when we act on the 

8-hour ozone and PM2.5 SIPs. As noted elsewhere, EPA's adequacy 

review process is separate from EPA's completeness review or any 

future SIP approvability actions. 

EPA's adequacy process involves a cursory review of the SIP's 

motor vehicle emissions budgets according to the adequacy 

criteria at 40 CFR 93.118(e)(4). As described elsewhere in 

today's finding, EPA believes that the State's "baseline" 

budgets meet this adequacy criteria, including that budgets are 

precisely quantified and consistent with and clearly related to 

control measures (40 CFR 93.118(e)(4)(iii) and (v)). EPA has 

determined for its adequacy review that the Smog Check 

reductions in the "baseline" budgets are consistent with the 

Inspection and Maintenance (I/M) reductions included in the 

EMFAC2007 emissions factor model, which EPA approved this model 

for SIP development purposes on January 18, 2008 (73 FR 3464). 

The technical support documents to EMFAC2007 reflect the most 

current information used to assess the effectiveness of the Smog 

Check program. 

EPA notes that CARB uses the EMFAC motor vehicle emissions model 

to estimate emission reductions for the Smog Check program. The 

EMFAC model uses emission regimes to define the emission level 

for each vehicle. Vehicles that fail Smog Check and then get 

repaired are redistributed among the emission regimes according 

to an after-repair move matrix. The after-repair move matrices 

used in EMFAC are based on data collected by ARB during in-use 

vehicle studies. As part of the 2004 Smog Check Program 
7

evaluation, Sierra Research analyzed data collected from 

roadside testing of vehicles. EPA will consider any results 

from this and other documentation in its future SIP action on 

the South Coast SIP. 

Further, the commenters do not provide any quantification of the 

impact of these issues on the motor vehicle emissions budgets, 

nor do we have any other information regarding the magnitude of 

any potential miscalculation. Without this evidence, we are 

unable to consider the comment in our adequacy finding. 

Comment 8: The commenter asserts that EPA should require CARB to 

achieve greater emissions reductions from the use of retrofits, 

especially tailpipe (after treatment) retrofits as has been 

mentioned in the International Sustainable Systems Research 

Center’s report, and from requirements to use cleaner 

alternative fuels in the heavy-duty or light-duty vehicle 

sector. 

Response 8: This comment is outside the scope of EPA’s adequacy

review. We appreciate the comments relating to retrofits and 

the use of cleaner alternative fuels and we will examine, when 

we take rulemaking action on the plan, whether the SIP 

sufficiently demonstrates attainment for PM2.5 or 8-hour ozone. 

In this future rulemaking action, we will consider whether any 

additional measures will be needed to meet attainment for these 

pollutants. As documented elsewhere in this letter, EPA has 

found the 8-hour ozone and PM2.5 attainment budgets to be 

inadequate for transportation conformity purposes. 

Comment 9: The commenter asserts that EPA cannot allow the 

SCAQMD to assume a 100% rule effectiveness rate for its control 

measures and cites various EPA documents for support for this 

assertion. 

Response 9: The comment primarily addresses SCAQMD's calculation 

of stationary and area source emissions, rather than the State's 

estimation of motor vehicle emissions. As such, this comment is 

not relevant to EPA’s adequacy review of the motor vehicle 

emissions budgets. We intend to examine the issue raised by the 

commenters regarding the compliance rate assumptions in the plan 

as we undertake our rulemaking action on the SIP. 

Comment 10: The commenter concludes that the contingency 

measures in the plan are based on an erroneous interpretation of 

the law, and asserts that EPA must require that California 

include legally adequate contingency measures. 
8

Response 10: This issue is outside the scope of EPA’s adequacy 

review of the budgets, which is separate from EPA’s completeness 

and approval reviews. We will review the approvability of the 

contingency provisions when we undertake rulemaking on the plan. 

Comment 11: Citing EPA’s failure to adopt and implement 

necessary pollution reduction measures as an ongoing problem 

with the SIP process, the commenter states that EPA must 

contribute more pollution reductions and include those 

reductions in California’s SIP. The commenter observes that EPA 

has authority to regulate certain sources of pollution that 

neither CARB nor the Air Districts have and that attainment of 

the NAAQS, EPA must exercise the authority it has or must 

delegate more authority to air quality agencies in California. 

Response 11: This comment is outside the scope of today’s 

decisions regarding the adequacy of the submitted motor vehicle 

emissions budgets. However, EPA notes the commenter’s concerns 

regarding EPA’s responsibility and authority to regulate certain 

sources of pollution. EPA has adopted several national 

regulations that will result in significant emissions reductions 

benefits in the South Coast Air Basin, including the Clean Air 

Nonroad Diesel Rule (69 FR 38957, June 29, 2004) and the Heavy 

Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur 

Control Requirements (66 FR 5002, Jan. 18, 2001). Most recently, 

on March 13, 2008, the EPA adopted standards to reduce emissions 

of diesel particulate matter and NOx from locomotives and marine 

diesel engines. 

Comment 12: The commenter concludes that EPA cannot reasonably

deem the emissions budgets adequate at this time, in light of 

the specific defects in the emissions budgets, as well as the 

many defects in the currently-submitted SIP, that have been 

identified by the commenter, and must therefore find the 

submitted budgets inadequate. 

Response 12: As stated above, EPA has found the motor vehicle 

emissions budgets that include new emissions reductions from 

general commitments submitted in the 8-hour ozone and PM2.5 SIP 

to be inadequate for transportation conformity purposes. EPA has 

determined that these budgets are inadequate because they do not 

meet the transportation conformity adequacy criteria found at 40 

CFR 93.118(e)(4)(iii), (iv) and (v). The budgets that we are 

finding adequate at this time are only those associated with the 

baseline emissions for RFP milestones and control measures that 

are already being implemented (“baseline” budgets).
9

Response to Comments from Coalition for Clean Air, Coalition for 

a Safe Environment, Endangered Habitats League, Environmental 

Defense Fund, East Yard Communities for Environmental Justice, 

and the Natural Resources Defense Council (Received: April 28, 

2008)

Comment 1: The commenter objects to the submitted interim 

budgets for PM2.5 based on two broad concerns. First, the 

commenter finds that the attainment demonstration fails to 

identify the elevated concentrations of PM2.5 in the near-highway 

environment, to estimate the emissions reductions needed to 

attain the NAAQS in the near-highway environment, and to include 

a control strategy designed to reduce these elevated nearhighway concentrations to the level of the NAAQS. Second, the 

commenter objects to the plan’s reliance on measures that may 

not be implemented in the relevant horizon year (or at all), for 

the purposes of demonstrating attainment and RFP, citing several 

source categories for which assumed emissions reductions may not 

occur due to legal challenges, outlying implementation dates, or 

reliance upon voluntary compliance. 

Response 1: EPA believes that these comments are outside of the

scope of its adequacy action on the motor vehicle emissions 

budgets. EPA will consider these comments on the PM2.5 attainment 

demonstration and near-roadway particulate matter emissions when 

it takes rulemaking action on the 8-hour ozone and PM2.5 2007 

South Coast SIP. 

Although EPA believes that these comments are outside of the 

scope of its adequacy action on the motor vehicle emissions 

budgets, EPA is concerned about the particulate matter exposure 

that is described by the commenters. EPA Region 9, CARB, and 

SCAQMD are currently undertaking both area-specific and more 

general monitoring and analytical projects to improve our 

understanding of the location, amount, and causes of elevated 

near-roadway ambient concentrations. For example, the SCAQMD has 

initiated a monitoring study to measure air pollutants generated 

by the freeway traffic and to determine the impacts on adjacent 

residential communities along the I-710 corridor. The study will 

compare pollutant levels measured at monitors located adjacent 

to the freeway to pollutant levels at distances representative 

of community exposure located further downwind (100-300 meters). 

First, EPA is only taking action on the 2009 and 2012 PM2.5 RFP 

budgets, which do not rely on the new emission reductions about 

which commenters expressed concern. These “baseline” budgets are 

consistent with the State’s reasonable further progress 
10

demonstrations for 8-hour ozone and PM2.5 as well as adopted 

control measures that have already been implemented. Today, we 

have also concluded for purposes of motor vehicle emissions 

budget adequacy that the budgets, when considered together with 

all other emissions sources, are consistent with the requirement 

to achieve reasonable further progress pursuant to 40 CFR 

93.118(e)(4)(iv). This finding is based EPA’s cursory review of 

the State’s RFP modeled demonstration that reasonably identifies 

PM2.5 precursor attainment targets for the South Coast Air Basin. 

Thus, this demonstration establishes approximate levels of 

emissions reductions necessary to achieve generally linear 

progress for the 2009 and 2012 PM2.5 Reasonable Further Progress 

milestones, as required by EPA's PM2.5 Implementation Rule. The 

“baseline” budgets also meet the other adequacy criteria, 

including being precisely quantified and clearly related to the 

overall SIP, as described elsewhere in today’s finding. 

In addition, we are not finding adequate the motor vehicle 

emissions budgets associated with the attainment year because of 

our conclusion that new emissions reductions upon which the PM2.5

attainment demonstration rests do not comply with the 

transportation conformity adequacy criteria in 40 CFR 

93.118(e)(4) that relate to having specified control measures. 

EPA will consider these concerns when we take action on the PM2.5

SIP's modeled attainment demonstration, reasonable further 

progress demonstration, and control strategies. 

Finally, EPA believes that the commenters’ request to conduct 

additional procedures for adequacy review is outside the scope 

of today’s adequacy review on the South Coast SIP budgets. In 

its July 1, 2004 final “Transportation Conformity Rule 

Amendments for the New 8-hour Ozone and PM2.5 National Ambient 

Air Quality Standards and Miscellaneous Revisions for Existing 

Areas” (69 FR 40041), EPA held that adequacy findings do not 

need to be made through APA notice and comment rulemaking. 

Today’s action followed the EPA’s established adequacy process 

under 40 CFR 93.118(f), providing a 30-day public comment period 

and the findings will be published in the Federal Register 

before becoming effective. EPA has sent its response to comments 

received on the adequacy of the submitted SIP budgets to the 

State along with its adequacy finding letter. EPA will also send 

our letter, response to comments, and Federal Register notice to 

individuals who request a copy of these documents. EPA will also 

post its adequacy finding and FR notice on its adequacy website, 

as required by the transportation conformity rule. Please see 

the preamble to the July 2004 final rule for further information 

regarding EPA’s adequacy process (40 CFR 40038-40047).