8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 20 ATTACHMENT

3 WRITTEN COMMENTS AND RESPONSES ON THE DRAFT RATE-OF-PROGRESS PLANMr. Greg Tholen Associate Air Quality Planner Sacramento Metropolitan Air Quality Management District (SMAQMD) Street, 3 rd Floor Sacramento,
CA 95814 Subject: Comments
on Sacramento Regional Nonattainmeni Area 8-hourOzone Rate-.of Progress Plan (ROt’)—Draft Report Dear Mr. Tholen: Thank you for the opportunity

to review and. comment on.the draft Rate of Progress (ROP) plan and the new emission inventories being considered for the Sacramento area. Along with our air quahty consultant. CH2M HILL, the Sacramento County Airport System (County Airport System, or SCAS) has reviewed the draft Rate of Progress (ROP) plan and its emission estimates. We offer the following, comments for consideration during the ROP adoption processes that will take place in early 2006. 1. Introduction and Overview Comment 1-1 Comment 1-2
As demonstrated below, the region’s air quality plans do not sufficiently
ac ount for the current and future level of aircraft operations, and for the construction activity urgently needed
to sup port those operations. Among other factors, the emergence

of STow’ cost” commercial
air carriers has made air travel truly affordable

to the public. The growth of such service
in the Sacramento area has eliminated the need for air travelers
to use distant airports such as Oakland and San Francisco. Postponing

or expanding the construction period for airport improvement prcects will potentially result In even higher emissions due to airfield and ground transportation congestion. Included

in the comments below
is a proposal for a two-part approach for ensuring an adequate future nitrogen oxide (NOx) emission budget for SCAS facilities: 1. Aircraft emissions budget
in 1994 ozone State Implementation Plan (SIP): consider trad ing the surplus volatile organic compounds (VOC) identified

in the plan for nitrogen ox ides (NOx); and 2. Under the new draft ozone SIP to. te completed

in June 2007. consider transferring any NOx surplus that may be indicated

in the on-road vehicle emssion budget to the aircraft budget. In addition,
as you know, SCAS has engaged

in a number of voluntary effoits to reduce emis sions at SMF. including the recently completed Inherently Low Emission Airport Vehicle (ILEAV) Comment Letter #1 8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 21 County Executive Terry Schutten Sacramento County Airport System G. Hardy Acree, Director
of Airports County of Sacramei October 27, 2005

Mather Airport Executive Airport Franklin Field 6900 Airport Boulevard

• Sacramento. California 95837

• phone (916) 8740719

• fax (916) 8740636 www.saccounty.net

• www.sacarports.org8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page22 Comment 1-3 SCASRATEOF PROGRESS COMMENT lITTER OCTOBER27, 2005 PAGE2OF8 pilot program partially funded bythe Federal Aviation Administration (FAA). The County Airport System will soonbegin preparing Emission Reduction Credit (ERC) applications
for theILEAV program,and looks forward
tothe assistance and supportof SMAQMD

in obtaining such ERCs. 2. General Comments__________

Itis imperative thatthe emission budget established for regional aircraft operations

inthe State Implementation Plan (SIP) reflect anticipated growth
inall regional aviation activities. Theair craft emission budget will serveasthe basis for determining compliance with the General Con__________ formity requirements associated with future growth ofallthe airports
inthe multi-county nonat tainment area.The aircraft emission budgets applytothe17 airports located
inthe Sacramento nonattainment area.An inadequate budget for aircraft emissions willlimitthe ability of thes.e airports
tomodernize and provide services
tomeetthe continued demand forairtravel. The Sacramento County Airport System (SCAS)

is responsible
forfour ofthese airports includ ing Sacramento International Airport (SMF), Mather Field (MHR), McClellan (MCC), Sacramento Executive (SAC), and Franklin Field (F72). SAC airport
is comprised
of approximately 740__________ acresowned bythe Cityof Sacramento (City). The facility
is leased and operated by SCASuderan agreementwith the City. SACisthe primary general aviation airport serving the Sacra mento Valley.
In addition, the Sacramento County Department

of Economic Development operatesMcClellan Airport (MCC). The County Airport System maintains portions
ofthe airfield under anagreementwith Economic Development Sacramento County
is striving tomake eachof the airportsflnancially viable by expanding operations and attracting newtenants. The remaining
12 airports
inthe rionattainment areaare operated by other entities with whichComment the County Airport System hasnoaffiliation
orinvolvement. Each ofthese airports function dif 1$ J ferently,
toservethe needs ofits tenantsand users.

ItIs prudent
to assume, however, that eachof these airports willalso experience future growth asthe regional poputation increases. Comment 1.7 The County Airport System’s July20. 2005 letterto SMAQMD
onthe draft ROP requested

a larger emissions budget for future aircraft activities because ofthe manyuncertainties

in making accurateaviation forecasts. Aircraft emissions aredriven bythe aircraft fleet mix, andawide variety ofaircraft types commonly operate
ateachofthe regional airports. Fleetmixis driven by demand, and demand

is largely driven by changes

in national economic environment, cou pledwith growth
inthe regional population and economy.

In addition, airlines constantly reas sign aircraft
to city pairs” based onfactors such as fluctuating market demand, load factors (percentage

of seats filled), and aircraft availability. An example
ofthe dynamic natureof aircraft scheduling

isthe recent elimination and rapid reinstatement

of flights by several airlines
in re— sponse
tofuel price spikes resulting from theukatrinan hurricane. Thenetresult
isthatin any given time spanthe samescheduled service maybe served byawide rangeof aircraft typesof varying age, engine vintage and emission levels.1 I Comment L 14 Comment 1-5

3. Aircraft Emission Budget A. Aircraft Variability 1 For example.

it can generally be assumed that
aBoeing 737-300 Willhave older, higher emitting engines than thenewermodel737-800.8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 23SCASRATEOFPROGRESSCOMMENTLETTEROCTOBER27.2005PAGE3Of8 B. Relationship Between Noise and Emissions In recent years the manufacturers

of airframes and aircraft engines have made great strides
In Comment reducing noise caused by commercial aircraft. The latest “Stage 3” engines with high pressure 1-8 ratios have resulted

in reduced noise, fuel use and emissions

of carbon monoxide (GO) and volatile organic compounds (VOCs) 2 ,but the higher operating temperatures

of these engines has had the unfortunate result of causing increased nitrogen oxide (NOx) emissions.

a factor not accounted for In the 1994 SIP budget developed

in the early 1990s. C. Aircraft Characteristics C mment

I Jet-powered (turbofan) aircraft are high NOx, and low VOC emitters, while piston aircraft are° 1-9

I high VOC. low NOx emitters. Turbo-prop powered aircraft are significant emitters of both pre J cursor pollutants. The amount of time an aircraft spends
in each flight mode (take-off, dimb-out, approach, and taxi/delay) also influences emissions. Thus, aircraft emissions

at each airport can vary greatly depending upon the activities and performance

of each type of aircraft, and numerous operational conditions

at each airfield. D. Air Travel Demand The current and forthcoming period of rapidly changing economic conditions, particularly

in the Comment commercial aviation industry, makes the activities
of future aircraft operations very hard to pre 1-10 dict. High fuel costs have forced many airlines
to change the aIrcraft fleet mix, and to make constant readjustments.

Air cargo activities have Increased due to congested marine ports and rail terminals, increased internet sales, and “just in time” inventory procedures. The stringent securityprocedures brought about by the 9-11 attacks have also increased the use of corporate aircraft at smaller airports. E. Airport Master Plans An airport operator

is held responsible
for airport emissions, but has no control of travel de Comment mend, the types of aircraft used, or of ongoing military activities. Regional airport operators will 1-11 not be able to modernize and expand
to meet travel demand

If the SIP emission budgets estab lished for aircraft are inadequate. Past experience with the delay in constructing Terminal

A at SMF has shown that aIr travel demand continues

to increase, even when airfield facilities are limited, Inadequate airport facilities generate greater emissions due to congestion and ineffi dent operations

of aircraft, ground support equipment (GSE), and ground access vehicles (GAy).V The SCAS recently prepared Airport Master Plans for SMF and MHR that forecast activities Comment over
a 20-year period. These plans anticipate growth
in passengers,

air cargo, aircraft opera- 1-12 J tions, and emissions, and identified

a number of improvements

to increase the efficiency
of each airfield. However, SMF is currently growing faster than anticipated. Attachment

I is a ta ble summarizing aircraft activity at SMF, MHR and SAC for the 12 months ending August 30, 2005. During that period SMF air passenger use grew by more than eight percent, air cargo grew by more than two percent, and aircraft operations grew by almost 0.6 percent. (This growth
is not related
to post terrorist attach recovery, because SMF passenger traffic returned to pre-September 2001 levels by April 2002.) Significantly,
the 12-month SMF passenger count2ema&yreferredtoashydrocarbons(HC).3ThapricetopayforveiyhighbypassratIoenginesIsIncreasedsize,weightanddrag,whichresultingreaterfuelburn.Inaddition,higherbypassratioenginesrequiremuchhigherpressureratios,whichimplyhigherenginecoretemperaturesandmayhaveanegativeeffectonemissions,especiallyoxidesofnitrogen.Thesecostsmustbeweighedagainstthenoisebenefits.’EnvironmentalReview2004,InternationalAirTransportAssociaBon(JATA),p.7.8-Hour Ozone Rate-of-Progress
Plan January 26, 2006 Page24 SCASRATE OF PRCORESS COMMENT 1.ETTER OCTOBER 272005 PAGE4OF

B reached tenmillion for the first time in August 2005, having increased from nine million annually just14 months earlier for the12months ending June 2004. The future fleet mix may change
to anincreased useof larger aircraft and smaller regional jets (RJs).
A master plan will soonbe prepared forSAC and F72, and perhaps MCC. The growth impact ofthese airports wasnot anticipated

intheSIP budget currently available for future aircraft emissions. 4. Conformity Concerns During the recentROP workshop

atthe SMAQMD.

awide variety of regional sourcesweredis cussed. The emissions
of on-road vehicles wereof particular interest because
ofthe recent withholding

of federal funding and approvals for needed roadway Improvement projects.

A “Transportation Conformity” lapse occurred

in October 2004 because the regional transportation plansdid notmeetthe emissions budget that had been established
for region-wide vehicle activities. The 1994 SIP on-road vehicle emission budgets werebased onold EMFAC7F com putermodel emission factors and travel assumptions developed during the early 1990s. Themostcurrenton-road vehicle emission estimates arebased on improved EMFAC2002 Comment computermodel emission factors and updated travel assumptions. These latest ROP estimates1-14 have provided

alarger emissions budget for on-road vehicles. The transportation improvement plans maynowlit within the revised budget andbeabletomoveforward after reevaluation
US lugthelatest information. There areeven surplus NOx vehicle reductions anticipated, and someare planned
tobe substituted for hydrocarbons (HC), toreach the ROPHC reduction goals. However, aircraft emissions are regulated
bythe requirements

of “General Conformity”, thataredifferent from Transportation Conformity. The SMAQMD has recently become awarethat (unlike Transportation Conformity) USEPA guidelines
donot recognize the recentROP ernis sion updates asan “applicable SIP”,andthe latest emission aircraft estimates cannotbe used toestablish
anupdated budget. Thus,

averysimilar conformity lapse situation mayoccurwiththe regional airports

if their airfield improvement plans donotmeettheold 1994 SIP budget established
for aircraft. New General__________ Conformity budgets willbe established withthe “attainment SIP” scheduled for June 2007. The budgets established

inthis newSIPwillnotbecome applicable until approved bythe USEPA, which maytake six months ormore. Therefore, regional airport improvement projects will have tocontinue
tobe approved using the outdated 1994SIP aircraft budget, which leaves little roomforfuture airport growth. Muchhas changed since the early 1990’s when theold 1994SIP budget for aircraft waspre pared. Atthat time,SIP budget emission forecasts only extended

to2005. SMFwas growing rapidly, andMHR wasinthe processof being converted into
acivilian airport. The future activi tiesofMCC wereuncertain because
its future asanAirForce base wasunknown
atthattime. Regional general aviation activities wereonthe decrease, andmostofthesmall airfields wereassumed

tobe stagnant. Also,the accuracy
ofthe aircraft fleet mix operations maynothave adequately represented general aviation emissions because consistent records werenot keptatthe various smaller airports. CommentAnalyses
of currentaircraft emissions show thatSMF andMHRnowconsumemostofthe NOx 1-18budget allotted
inthe 1994 SIP. Recent Master PlansforSMF and MHR have estimated that__________ aircraft operations will increase
atboth airports between nowand 2020. Emission calculations, based onthe2010 forecasted aircraft fleet mix, showthat 99%ofthe NOX budget, and 41%of theHC budgetwill be consumed
bythese two airports alone. This leaves little margin for error. Comment 1.16 Comment 1-178-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 25SCASRP.TEOFPROGRESSCOMMENTLETTEROCTO0ER272005PAGE5OF and may hamper plans for SCAS improvements until
a larger aircraft emissions budget be comes available

in the attainment SIP. 5. Timing of “Attainment SIP” Budget with Planned SCAS Airfield Improvements Comment 1-21 SCAS has many airport improvement projects planned between 2006 and 2010 that are likely to make

it difficult
to stay within the outdated 1994 budget. The forecast growth
in flight operations may increase aircraft emissions

at the SCAS airports faster than the approval schedules
of the new SIP aircraft budget The SMAQMD and the Airport System must continue
to work together to increase the aircraft budget while resoMng other General Conformity issues. SCAS recently began preparation

of environmental documents for the SMF Master Plan. Preparation

of environmental documents for the MHR Master Plan is expected
to begin in mid- 2006.

It is anticipated that approximately two years will be required
to gain environmental
ap proval for each of the Master Plans before the projects
at these airports can move forward. SCAS also plans to begin

a new Master Plan for SAC airport and Franklin Field in 2006, with preparation

of environmental documents anticipated

to begin in 2008. The Federal Aviation Administration

is the lead agency responsible
for determining that the air field projects expected by 2010 meet the requirements

of General Conformity. Approval
of the environmental documents for the various Master Plans will require that future aircraft emissions fit within the applicable budget, and that total direct and indirect emissions growth does not ex ceed the 50 tons!calèndar year de minlmus threshold established

by General Conformity. Dur ing this period

it will likely be hard to stay within the outdated and inadequate SIP aircraft budget, and gain environmental document approvals needed
to construct the various planned airfield improvements. Anticipated major SCAS construction projects by 2010 indude: SMF 2006—2010 Construct new FAA control tower Extend the east runway and construct new cross field taxiway Improve on-airport roadways Expand the rental car facility Construct air cargo building and apron Overlay taxiway

D Demolish and rebuild terminal

B MHR 2006—2010 Rehabilitate runway pavement Install instrument landing system Construct air cargo access roadway Upgrade roadways and vehicle parking lots Extend runway 4L-22R, and upgrade taxiways8-Hour Ozone Rate-of-Progress Plan January 26,2006 Page26 SCASRATEOF PROGRESS COMMENT LETTER OCTOBER27. 20C5 PAGE

6OFB Construct
anadditional runway Construct air cargofeeder rampand warehouse/sort facility Construct miscellaneous improvements SAC 2006—2010 Improve aircraft ramp pavement areas Construct airfield maintenance facility 6. Potential Solutions A. Emission Budgets The outdated 1994 aircraft SIP budgets currently applicable arevery tightfor NOx emissions,Comment but contain morethan adequate amountsof hydrocarbon (MC) emissions. We requestthat1-22 SMAQMD consider allocating

aportion ofthe someofthe surplus HGfor NOX.
Ifthis substitu tionis possible,

itwould increase the NOx budget available for future aircraft operations andal lowthe SCAS projects
tomoveforward
inthe interim.
Anew larger emissions budget forair craft would needtobe established

inthe upcoming attainment SIP budget that would continue to supportincreases

in aircraft emissions. Once theROP hasbeen approved, the region must prepareanozoneattainment plan demonComment stration thatwillbe based upon photochemical modeling. This newplanwill project the regional 1.23

I emissions inventory and motorvehicle emission budgets through the attainment deadline
of1 2013. Photochemical modeling will determine

ifthe anticipated total emission reductions within the region will meetthe 8-hour ozonestandard.

Ifitis shown that the standard willbe met,the region will concentrate

oninsuring that emissions aremaintained within the emission budgets established

inthe attainment plan. Should this occurthere maybe waystoincrease the budget for aircraft emissions without exComment ceeding the overall regional emission quantities. TheROP inventory currently anticipates that124 about 25 tonslday
of surplus NOx reductions from on-road vehicles maybe available.

Ifthis NOx surplus

is showntostillbe available after photochemical modeling, perhaps

asmall portion ofitcanbe allocated
tothe aircraft budget portion ofthe attainment SIP. However,

if photochemical modeling shows that attainment cannotbe demonstrated

by 2013,Comment
the SMAQMD may request

a“bump up”to“severe” nonattainment statusthat would extend the125 attainment deadline
to2019. Unfortunately,
this could have major implications
forthe airport Improvements because the “bump up”would decrease the General Conformity
de minimus threshold
to25 tons/year. Giventhe number of construction projects included the Master Plans, construction equipment emissions could potentially exceed the 25-ton/year threshold, making

it difficulttoachieve the mitigation reductions needed
to approvethe environmental documents for the airport Master Plans. B. Emission Reduction Credits (ERCs) rSMFwasoneoftencommercial airports that received

a matching grantfrom theFAA for the Comment purposeof demonstrating
the efficacy of various technologies

in reducing airport related emis 1.26sions. The projects implemented

atSMF under theILEAV programindude replacement

ofL

I twentydiesel powered busses with CNG busses, an upgrade
tothe CNG refueling facility, re8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 27SCASRb.TEOFPROGRESSCOMMENTLETTEROCIOBER27.2D05PAGE708 placement

of gasoline-powered
OSE by three airlines, and other accomplishments.

In addition to the ILEAV projects, emissions from aircraft auxiliary power units (APUs) have been greatly reduced through the provision
of 28 jet bridges equipped with 400 hz power and preconditioned air. SCAS anticipates submitting Emission Reduction Credit (ERC) applications
for many of these projects,

in anticipation

of applying the credits toward construction-related emissions.
Si erra Research,

a consultant

to SCAS, submitted
an ERC application for the recently completed jet fuel pipeline and fuel storage facilities, which WILT eliminate about 30 roundtrip diesel powered delivery trips daily. Earlier this year the FAA and USEPA developed ERC guidelines for such activities pursuant

to the Voluntary Airport Low Emissions (VALE) program. Finally, as you know, SMAQMD successfully nominated the above activities for recognition

as a “Clean Air Champion”
by the Sacramento-Emigrant Trails chapter of the American Lung Association. 7. Conclusions It is imperative that the emission budgets established within the applicable SIP be adequate
to Comment permit the future growth of aircraft operations

in the region. Currently, only the outdated 1994 SIP aircraft budgets are applicable, and they are based on outdated information. Many future improvements
are planned for the airports operated

in Sacramento County by the Comment SCAS. These improvements
are needed
to meet the demand for air travel services that grows 1.28 With the regional population and economy. Numerous small airports iocated within the nonat tainment area may also wish to expand their activities, and the SIP does not adequately account For that posslbiflty. The timing of SCAS airport improvement projects

is out of phase with the regulatory schedule
of Comment preparing and approving

a new attainment SIP budget. This makes

it difficult for the environ- 1-29 mental documents associated with the SMF and MHR Master Plans to be approved. Additional Master Plans and environmental documents will be prepared for the remaining SCAS airports that will eventually encounter the same difficulty

in obtaining approval

in a timely manner.

In the interim, we recommend that the SMAQMD allocate some of the excess HC emissions (currently available

in the 1994 SIP aircraft budget)
to the NOx aircraft budget. This will enable the airport projects
to move forward until
a new attainment SIP budget

Is available. if the current ROP emissions inventory

is carried forward into the attainment SIP, and proves to Comment

be adequate

to demonstrate attainment, there should be excess NOx emissions available within 1-30 the region.
A small portion of this NOx excess could then be allocated
to the aircraft budget without threatening attainment progress. An increased NOx budget for future aircraft activities will enable the planned airport projects
to move forward and meet the future demands
of re gIonal air travel services. Please contact me at 916-874-0698

if you have any questions about the above comments. Sincerely, ‘cWQ Senior Environmental Analyst C: Leonard Takayama, Deputy Director— Planning and Development George Munson, Airport Planner— Planning and Development8-I-tour Ozone Rate-of-Progress Plan January 26, 2006 Page 28 SCASPATE06 PROGnESS COMMENTLETtER OCTOBER 27, 2006 PAGE

BOFB Attachment

I SOAS Flight Statistics for the 12 Months Ending August 30. 2005 August August Last 12 Months Last 12 Months 1f!1 IU rrt

2004 o=————— InAugust2005coniparedto Passengers 932,688 893)985 10,027,321 9,266,821 August2004. NFreight(rcns)
6795 5,479 66,391 64)910 Aircraft operations

at Executive Akcalt Operations 16,405 15,659 163,496 164,448 Alrpott were q2&4%

in August 2005 compared

to August 2004 i4kpj Aircraft Operations 13,206 10,521 114,372 136,493 ),..-rEjt E’J $M!

, Air Freight (lbns) 5,960 6,448 63,099 64,161 Aircraft Operations 8,507 8,014 82,108 78,891 Source: Airmail, October 19, 2005. Sacramento County Airport System WPLANNING’ENVIRONMENTALWr QuaIitySIP Update_ 2004Rate
of Progress Plan20D5ROP_Comments(2)4oc8-Hour Ozone Rate-of-Progress
Plan January 26, 2006 Page 29 Responses

to Comment Letter #1— Greg Rowe, Sacramento County Airport System (12112105) Thank you for your comments (Greg Rowe letter, dated 10/27/05)
on the Sacramento Regional Nonattainment Area 8-Hour Ozone Rate-of-Progress Plan (Draft Report, dated September 2005). We understand your concerns regarding the proposed emissions inventories
for airports, especially for 2008 and beyond. SMAQMD staff will work closely with Sacramento County Airport System (SCAS) staff to document and evaluate potentially higher than anticipated growth
at Sacramento International, Mather Field, McClellan Airport, Sacramento Executive, and Franklin Field as we develop the regional airports emissions inventory for the upcoming 8-hour ozone attainment plan due in 2007.
In addition, SMAQMD staff will continue
to explore options available

in the General Conformity Rule for showing general conformity for near-term airport projects under the existing SIP aircraft emissions inventory. Below are responses

to your specific comments

in your letter: 1. Introduction and Overview Response

to Comment 1-1: Comments noted. The surge
in current and anticipated airport activity must be documented

so that we can incorporate revised growth rates for aircraft and ground support equipment activity
in the next state implementation plan (SIP) submittal. Response

to Comment 1-2: Comments noted. Regarding your Proposal

I for ensuring
an adequate future aircraft NOx emissions inventory budget, General Conformity Rules (40 CFR §93, Subpart
B) do not allow the trading of volatile organic compound emissions budget surplus for nitrogen oxide emissions budget shortfalls. EPA is revising the General Conformity Rule which
is anticipated

to be published

in June 2006. To the extent this revision of the rule allows for inter-pollutant trading, the District will work with SCAS to evaluate incorporating surplus emissions. Regarding your Proposal

2 for ensuring
an adequate future aircraft NOx emissions inventory budget, preliminary photochemical modeling results indicate that additional ozone precursor emission reductions will be needed
to demonstrate attainment

of the ozone standard by the 2013 attainment year in the Sacramento region. Because
of the need for additional NOx for the attainment demonstration,
the transfer
of surplus NOx will be evaluated during that attainment demonstration planning process.8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 30 General Conformity Rules do address the following conformity requirement options as follows: For a required action to meet the conformity determination emissions criteria, the total of direct and indirect emissions from the action must be in compliance

or consistent with all relevant requirements and milestones contained

in the applicable SIP (40 CFR §93.158(c)), and in addition must meet other specified requirements, such as: • For any criteria pollutant, the total of direct and indirect emissions from the action
is specifically identified and accounted
for in the applicable SIP’s attainment

or maintenance demonstration
(40 CFR §93.158(a)(1));

or • For ozone or nitrogen dioxide, the total of direct and indirect emissions from the action
is fully offset within the same nonattainment

(or maintenance) area through

a revision
to the applicable SIP or a similarly enforceable measure that effects emission reductions
so that there
is no net increase

in emissions

of that pollutant (40 CFR §93.158(a)(2));or • For ozone or nitrogen dioxide, the total of direct and indirect emissions from the action
is determined and documented

by the State agency primarily responsible
for the applicable SIP to result
in a level of emissions which, together with all other emissions

in the nonattainment

(or maintenance) area, would not exceed the emissions inventory specified

in the applicable SIP (40 CFR §93.158(a)(5)(i)(A));

or • For ozone or nitrogen dioxide, the total of direct and indirect emissions from the action
is determined
by the State agency responsible
for the applicable SIP to result in a level of emissions which, together with all other emissions

in the nonattainment (or maintenance) area, would exceed the emissions inventory specified

in the applicable SIP and the State Governor
or the Governor’s designee for SIP actions makes

a written commitment

to EPA for specific SIP revision measures reducing emissions

to not exceed the emissions inventory (40 CFR §93.158(a)(5)Q)(B)). Response

to Comment 1-3: Your comments are noted regarding SCAS efforts
to reduce emissions

at SMF. SMAQMD staff will work with SCAS staff to determine the eligibility
of SMF emission reductions for emission reduction credits. 2. General Comments Response

to Comment 1-4: Comments noted. SMAQMD staff worked very closely with SCAS contractor CH2M Hill on the recent update
to the aircraft emission inventory for the region. Together we8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 31 reviewed and updated emission factors, future aircraft fleet mix) and mixing height calculations which were used to update the 2002 emissions inventory. SMAQMD will continue
to work with Sacramento County Airport System (SCAS) staff to document and evaluate potentially higher than anticipated growth at Sacramento International, Mather Field) McClellan Airport, Sacramento Executive, and Franklin Field as we develop the regional airports emissions inventory for the upcoming 8-hour ozone attainment plan due in 2007. Response

to Comment 1-5: Comments noted. Response

to Comment 1-6: Comments iioted. Future growth for the remaining

12 airports

in the region
is included

in the forecast using California Air Resources Board (GARB) growth factors. 3. Aircraft Emission Budget Response

to Comment 1-7: Your comments are noted regarding the SCAS July 20, 2005 letter to SMAQMD requesting

a larger emissions budget for future aircraft activities due to the uncertainties in making accurate aviation forecasts. SMAQMD staff sent you a response letter (dated November

7, 2005) requesting more specific information and documentation

for airport activity growth and emissions) and timing of conformity determinations

for upcoming actions. Response

to Comment 1-8: Comments noted. SMAQMD staff worked very closely with SCAS contractor CH2M Hill on the recent update to the aircraft emission inventory for the region. This work resulted in an update to the growth and control methodology incorporating
the impacts
of engine design changes and increases

in passenger loading providing

a more accurate projection
of aircraft emissions. Response

to Comment 1-9: Comments noted. Updated aircraft inventory reflects the time spent in each flight mode as provided by CH2M Hill. Response

to Comment 1-10:8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 32 Comments noted. Growth estimates included

in the various Master Plans arebased on the best available data atthe time. SMAQMD used these estimates

to calculate growth and control factors for future yearsoutto2020. Greater than anticipated growth can only be addressed

in subsequent revisions and updates
tothe inventory. SMAQMD staff will continue

towork closely with SCAS contractor CH2M Hill to update future aircraft emission inventories for the region. Response

to Comment 1-li: See Response

to Comment 1-1. Response

to Comment 1-12: See Response

to Comments
1-4 and 1-10 4. Conformity Concerns Response

to Comment 1-13: Comments noted. Response

to Comment 1-14: Comments noted. Response

to Comment 1-15: Comments noted. Current federal rules (40 CFR §93.158) do not currently allow for the emissions inventory

in this Rate-of-Progress
Plan tobe applicable
for general conformity purposes,since the inventory mustbe from an applicable SIP’s attainment

or maintenance demonstration. Therefore, the existing attainment demonstration
SIP emissions inventory

is established

in the 1994 Sacramento Area Regional Ozone Attainment Plan. The next attainment demonstration
SIP submittal for the Sacramento nonattainment areawill be for the federal 8-hour ozonestandard due in 2007. However, EPA is revising the General Conformity Rule which
is anticipated

tobe published

in June 2006. To the extent this revision
of the rule allows for general conformity emissions levels tobe updated through the ROP process,the District will work diligently with State, local, and other agencies

to incorporate the ROP’s 2008 aircraft emission levels. Response

to Comment 1-16:8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 33 Comments noted. SMAQMD staff will continue

to work with Department

of Airports staff to explore options available

in the General Conformity Rule (mentioned

in Response

to Comment 1-2) for showing general conformity. Response

to Comment 1-17: The 2002 ROP inventory reflects improvements

to more accurately represent the current level of aircraft emissions and future emissions based on currently available data. Growth factors, aircraft fleet mix, and meteorological parameters used
in calculating aircraft emission factors were reviewed and updated

in coordination with CH2M Hill, CARB, and SMAQMD staff. Response

to Comment 1-18: See Response

to Comment 1-4. 5. Timing of “Attainment SIP” Budget with Planned SCAS Airfield Improvements Response

to Comment 1-19: See Response

to Comment 1-4 and 1-15 Response

to Comment 1-20: Current inventory uses forecasted activities from the approved Airport Master Plans,

It should be noted that the inventory documentation needed
to address the issues raised in these comments

is required by July 2006 to be incorporated into the 2007 Attainment Demonstration SIP. Response

to Comment 1-21: See Responses

to Comments 1-16, 1-15, and 1-4. 6. Potential Solutions Response

to Comment 1-22: See Responses

to Comments 1-2, 1-1, and 1-4. Response

to Comment 1-23: Comments noted.‘8-Hour Ozone Rate-of-Progress Plan January 26, 2006 Page 34 Response

to Comment 1-24: Comments noted. Preliminary photochemical modeling results indicate that additional ozone precursoremission reductions will be needed
to demonstrate attainment

of the ozonestandard
by the 2013 attainment yearin the Sacramento region. Also, see Responses

to Comments
1-1 and 1-4. Response

to Comment 1-25: The region will consider this issue when the need for a “bump up” is considered. Response

to Comment 1-26: See Response

to Comment 1-3. 7. Conclusions Response

to Comment 1-27: The Air District staff will work diligently with SCAS and other Federal, State, and local agencies

to prepareanaircraft emissions inventory that addresses growth for the region’s airports and demonstrate attainment.
To reach this goal, growth data, aircraft fleet mix, and operations data mustbe provided

in time to accommodate

a thorough review and validation prior to updating the inventory for submittal along with the 2007 Attainment Demonstration SIP. Response

toComment 1-28: See Responses

to Comments 1-1, 1-4 and 1-6. Response

to Comments 1-29 and 1-30: Unfortunately,
the current General Conformity rules do notallow this ROP SIP to update the aircraft emission inventory. Therefore, this important issue mustbe addressed

in the 2007 Attainment Demonstration SIP.