28830 Federal Register / Vol. 69, No. 97 / Wednesday, May 19, 2004 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 51 

[FRL–7663–6] 

Official Release of the MOBILE6.2 

Motor Vehicle Emissions Factor Model 

and the December 2003 AP–42 

Methods for Re-Entrained Road Dust

AGENCY: Environmental Protection 

Agency (EPA).

ACTION: Notice of availability.

SUMMARY: EPA is approving and 

announcing the availability of the 

MOBILE6.2 motor vehicle emissions 

factor model for official use in 

particulate matter (PM10 and PM2.5) SIPs 

and transportation conformity 

determinations outside of California. 

MOBILE6.2 is an update to MOBILE6 

which adds the capability to estimate 

direct exhaust and brake and tire wear 

particulate matter emission factors for 

PM10 and PM2.5, and exhaust emission 

factors for particulate precursors to the 

MOBILE6 model. MOBILE6.2 is a 

substantial improvement over previous 

methods for estimating PM emissions 

and incorporates EPA’s most current 

estimates of PM emissions for use by 

state and local governments to meet 

Clean Air Act requirements. 

EPA is also approving and 

announcing the availability of new 

methods for the estimation of reentrained road dust emissions from cars, 

trucks, buses, and motorcycles on paved 

and unpaved roads for PM10 and PM2.5

state implementation plans (SIPs) and 

transportation conformity analyses. 

These new methods are incorporated in 

the December 2003 edition of Chapter 

13 of Compilation of Air Pollutant 

Emission Factors, AP–42, Fifth Edition, 

Volume I: Stationary Point and Area 

Sources. 

Today’s action also starts time periods 

after which MOBILE6.2 and the 

December 2003 AP–42 methods are 

required to be used in new 

transportation conformity analyses for 

PM10 emissions. 

EPA strongly encourages areas to use 

the interagency consultation process to 

examine how MOBILE6.2 and the 

December 2003 AP–42 methods will 

affect future transportation conformity 

analyses, so, if necessary, PM10 SIPs and 

motor vehicle emissions budgets can be 

revised with MOBILE6.2 and AP–42 or 

transportation plans and programs can 

be revised as appropriate prior to the 

end of the conformity grace period.

DATES: EPA’s approval of the 

MOBILE6.2 emissions factor model and 

December 2003 AP–42 methods for reentrained road dust is effective May 19, 

2004. See below for further information 

regarding how today’s approval starts 

time periods after which MOBILE6.2 

and the December 2003 AP–42 methods 

are required in new transportation 

conformity analyses and certain SIP and 

motor vehicle emissions budget 

revisions.

FOR FURTHER INFORMATION CONTACT: If 

you have questions on this notice, 

please send an e-mail to EPA at 

mobile@epa.gov or contact EPA at (734) 

214–4636 for technical model questions 

about MOBILE6.2. Please send an e-mail 

to EPA at info.chief@epa.gov or contact 

EPA at (919) 541–1000 for technical 

questions about the December 2003 AP–

42 methods.

SUPPLEMENTARY INFORMATION: 

Availability of Models and Support 

Materials 

Copies of the official version of the 

MOBILE6.2 model are available on 

EPA’s MOBILE Web site, http://

www.epa.gov/otaq/m6.htm. The 

MOBILE Web site also contains the 

following support materials for 

implementing the new model: a detailed 

MOBILE6.2 User’s Guide; EPA’s ‘‘Policy 

Guidance on the Use of MOBILE6.2 and 

the December 2003 AP–42 Method for 

Re-Entrained Road Dust for SIP 

Development and Transportation 

Conformity’’; EPA’s ‘‘Technical 

Guidance on the Use of MOBILE6.2 for 

Emission Inventory Preparation’’; and a 

list of Frequently Asked Questions 

about MOBILE6.2. EPA will continue to 

update this Web site in the future as 

other MOBILE6.2 support materials are 

developed. 

Individuals who wish to receive EPA 

announcements related to the MOBILE 

model should subscribe to the EPAMOBILENEWS e-mail listserver. To 

subscribe to the EPA-MOBILENEWS 

listserver, write the following in the 

body of the e-mail message: 

subscribe EPA-MOBILENEWS 

FIRSTNAME LASTNAME where 

FIRSTNAME and LASTNAME is your 

name (for example: John Smith) and 

send the e-mail to the EPA Listserver at 

listserver@unixmail.rtpnc.epa.gov.

Your e-mail address will then be 

added to the list of subscribers and a 

confirmation message will be sent to 

your e-mail address. Whenever a 

message is posted to the EPAMOBILENEWS listserver by the 

listserver owner (the Assessment and 

Standards Division of the EPA Office of 

Transportation and Air Quality), a copy 

of that message will be sent to every 

person who has subscribed. 

You can remove yourself from the list 

by sending another message to the 

listserver address. This message must be 

sent from the same e-mail address that 

you used to subscribe, and should 

contain the message: unsubscribe EPAMOBILENEWS. 

Copies of the official version of the 

December 2003 edition of Sections 

13.2.1 and 13.2.2 of AP–42 can be found 

at www.epa.gov/ttn/chief/ap42/ch13/

index.html. In the rest of this document, 

unless otherwise indicated, ‘‘AP–42’’

refers to the December 2003 edition of 

Sections 13.2.1 and 13.2.2 of AP–42.

I. What Is MOBILE6.2 and How Is It 

Different From MOBILE6? 

MOBILE is an EPA emissions factor 

model for estimating pollution from onroad motor vehicles in states outside of 

California. The model accounts for the 

emission impacts of factors such as 

changes in vehicle emission standards, 

changes in vehicle populations and 

activity, and variation in local 

conditions such as temperature, 

humidity, fuel quality, and air quality 

programs. 

MOBILE is used to calculate current 

and future inventories of motor vehicle 

emissions at the national and local 

level. These inventories are used to 

make decisions about air pollution 

policies and programs at the local, state 

and national level. Inventories based on 

MOBILE are also used to meet the 

federal Clean Air Act’s state 

implementation plan (SIP) and 

transportation conformity requirements. 

The previous version of MOBILE, 

known as MOBILE6, calculated 

emissions of volatile organic 

compounds (VOCs), nitrogen oxides 

(NOX) and carbon monoxide (CO) from 

passenger cars, motorcycles, buses, and 

light-duty and heavy-duty trucks. 

MOBILE6.2 is an update to MOBILE6 

which adds the capability to estimate 

direct particulate matter (PM) emission 

factors for PM10 and PM2.5, and emission 

factors for particulate precursors, to the 

original MOBILE6 model. In other 

words, MOBILE6.2 allows the 

estimation of emission factors for HC 

(and air toxics), NOX, CO, gaseous SO2, 

ammonia, and direct PM from vehicle 

exhaust and brake and tire wear. 

MOBILE6.2 also corrects some minor 

coding errors in the portion of the 

model code that estimates HC, NOX, and 

CO emission factors, and it adds the 

capability of entering hourly relative 

humidity values. MOBILE6.2 also 

incorporates some revisions to CO 

emission factors for cars and light-duty 

trucks that meet national low emission 

vehicle (NLEV), low emission vehicle 

(LEV), and Tier 2 vehicle standards. 

Federal Register / Vol. 69, No. 97 / Wednesday, May 19, 2004 / Rules and Regulations 28831

Functionally, MOBILE6.2 now replaces 

MOBILE6 as the highway vehicle 

emission factor model that EPA will 

maintain and support. 

II. What Is the Impact of MOBILE6.2 on 

Ozone and CO SIPs and Conformity 

Determinations? 

Although MOBILE6.2 includes some 

corrections and enhancements to parts 

of the model that estimate emissions of 

HC, NOX, and CO, the impact of these 

changes is generally small. Even though 

MOBILE6.2 is very similar to MOBILE6 

for these pollutants, states and local 

agencies outside of California should 

use MOBILE6.2 for future HC, NOX, and 

CO SIPs and conformity analyses in 

order to take full advantage of the 

improvements incorporated in this 

version. SIPs and conformity analyses 

already in progress with MOBILE6 can 

be completed using MOBILE6 as 

determined through the interagency 

consultation process. Because the 

changes in HC, NOX, and CO emissions 

in MOBILE6.2 are generally very small, 

the release of MOBILE6.2 does not start 

a new grace period before MOBILE6.2 is 

required to be used for all new 

transportation conformity analyses in 

ozone or CO nonattainment or 

maintenance areas and it does not 

trigger the need for any new ozone or 

CO SIP revisions. 

III. What Are the December 2003 AP–42 

Methods? 

Motor vehicle emissions inventories 

for PM are comprised of four 

components: exhaust emissions, 

emissions from brake wear, emissions 

from tire wear, and re-entrained road 

dust. MOBILE6.2 does not include the 

capability of estimating the emissions of 

re-entrained road dust as the result of 

motor vehicle activity. EPA has 

developed separate revised AP–42 

methodologies for estimating reentrained road dust from paved and 

unpaved roads. These new methods for 

estimating road dust emission factors for 

paved and unpaved roads are being 

incorporated in EPA’s document AP–42. 

These new AP–42 methodologies (AP–

42, Sections 13.2.1, Paved Roads and 

13.2.2, Unpaved Roads, each dated 

December 2003) replace previous 

methods for estimating re-entrained 

road dust emissions for these categories 

with some limitations. AP–42 is the 

approved method only for situations for 

which silt loading, mean vehicle weight, 

and mean vehicle speed fall within 

ranges given in AP–42 section 13.2.1.3 

and with reasonably free-flowing traffic. 

For other conditions, areas may use an 

appropriate method approved by EPA 

on a case-by-case basis. In some areas, 

alternate methods may be more 

appropriate than AP–42 given specific 

local conditions even within the 

parameters given in AP–42 section 

13.2.1.3. State and local agencies should 

consult with EPA for approval of 

alternative approaches. This policy is 

described in more detail in the 

document ‘‘Policy Guidance on the Use 

of MOBILE6.2 and the December 2003 

AP–42 Method for Re-Entrained Road 

Dust for SIP Development and 

Transportation Conformity’’ (available 

at http://www.epa.gov/otaq/models/

mobile6/mobil6.2_letter.pdf). The 

following discussion of the use of AP–

42 in SIPs and conformity 

determinations also applies to approved 

alternatives to AP–42.

IV. PM10 SIP Policy for MOBILE6.2 and 

AP–42 

EPA has articulated its policy 

regarding the use of MOBILE6.2 and 

AP–42 in PM10 SIP development in its 

‘‘Policy Guidance on the Use of 

MOBILE6.2 and the December 2003 AP–

42 Method for Re-Entrained Road Dust 

for SIP Development and Transportation 

Conformity.’’ Today’s action highlights 

certain aspects of the guidance, but state 

and local governments should refer to 

the guidance for more detailed 

information on how and when to use 

MOBILE6.2 and AP–42 in attainment 

and maintenance PM10 SIPs, inventory 

updates, and other PM10 SIP submission 

requirements. See Availability of 

Related SIP Policies to obtain the 

MOBILE6.2 and AP–42 policy guidance. 

PM10 SIPs that EPA has already 

approved are not typically required to 

be revised now that EPA has approved 

MOBILE6.2 and AP–42. Although 

MOBILE6.2 and AP–42 should be used 

in new PM10 SIP development as 

expeditiously as possible, EPA also 

recognizes the time and level of effort 

that States have already undertaken in 

PM10 SIP development with previous 

models or methods. States that have 

already submitted PM10 SIPs or will 

submit PM10 SIPs shortly after EPA’s 

approval of MOBILE6.2 and AP–42 are 

not required to revise these SIPs simply 

because a new motor vehicle emissions 

model is now available. States can 

choose to use MOBILE6.2 in these SIPs, 

for example, if it is determined that 

future conformity determinations would 

be ensured through such a SIP revision. 

However, EPA does not believe that a 

State’s use of an earlier model such as 

PART5 should be an obstacle to EPA 

approval for SIPs that have been or will 

soon be submitted, assuming that such 

SIPs are otherwise approvable and 

significant SIP work has already 

occurred (e.g., attainment modeling for 

an attainment SIP has already been 

completed with an earlier model). It 

would be unreasonable to require States 

to revise these SIPs with MOBILE6.2 

and AP–42 since significant work has 

already occurred, and EPA intends to 

act on these SIPs in a timely manner. 

States should use MOBILE6.2 and 

AP–42 where PM10 SIP development is 

in its initial stages or hasn’t progressed 

far enough along that switching to 

MOBILE6.2 and AP–42 would create a 

significantly adverse impact on State 

resources. For example, PM10 SIPs that 

will be submitted late in 2004 should be 

based on MOBILE6.2 and AP–42 since 

there is adequate time to incorporate the 

new model’s results. MOBILE6.2 and 

AP–42 should be incorporated into 

these SIPs since emissions estimates in 

these models are based on the best 

information currently available, as 

required by Clean Air Act section 

172(c)(3) and 40 CFR 51.112(a)(1). 

V. PM10 Transportation Conformity 

Policy for MOBILE6.2 and AP–42 

Transportation conformity is a Clean 

Air Act requirement to ensure that 

federally supported highway and transit 

activities are consistent with (‘‘conform 

to’’) the SIP. Conformity to a SIP means 

that a transportation activity will not 

cause or contribute to new air pollution 

violations; worsen existing violations; or 

delay timely attainment of federal air 

quality standards. 

The transportation conformity rule 

(40 CFR part 93) requires that 

conformity analyses be based on the 

latest motor vehicle emissions model 

approved by EPA. Section 176(c)(1) of 

the Clean Air Act states that ‘‘. * * * 

[t]he determination of conformity shall 

be based on the most recent estimates of 

emissions, and such estimates shall be 

determined from the most recent 

population, employment, travel, and 

congestion estimates * * *.’’ When we 

approve new emissions models such as 

MOBILE6.2 and AP–42, a grace period 

is established before the models are 

required for conformity analyses. The 

conformity rule provides for a grace 

period for new emissions models of 

between 3–24 months. 

EPA articulated its intentions for 

establishing the length of a conformity 

grace period in the preamble to the 1993 

transportation conformity rule (58 FR 

62211):

‘‘EPA and [the Department of 

Transportation (DOT)] will consider 

extending the grace period if the effects of the 

new emissions model are so significant that 

previous SIP demonstrations of what 

emission levels are consistent with 

attainment would be substantially affected. 

In such cases, States should have an 

28832 Federal Register / Vol. 69, No. 97 / Wednesday, May 19, 2004 / Rules and Regulations 

opportunity to revise their SIPs before MPOs 

must use the model’s new emissions factors.’’

In consultation with the DOT, EPA 

considers many factors in establishing 

the length of the grace period, including 

the degree of change in emissions 

models and the effects of the new model 

on the transportation planning process 

(40 CFR 93.111).

Upon consideration of all of these 

factors, EPA is establishing a 2-year 

grace period, which begins today and 

ends on May 19, 2006, before 

MOBILE6.2 and AP–42 are required for 

new PM10 conformity analyses in most 

cases. During this grace period, areas 

should use the interagency consultation 

process to examine how MOBILE6.2 and 

AP–42 will affect their future 

conformity determinations. 

However, the grace period will be 

shorter than 2 years for PM10 if an area 

revises its SIP and budgets with 

MOBILE6.2 and AP–42 and such 

budgets become applicable for 

conformity purposes prior to the end of 

the 2-year grace period. For example, if 

an area revises a previously submitted 

(but not approved) PART5-based PM10

SIP with MOBILE6.2 and AP–42 and 

EPA finds the revised budgets adequate 

for conformity, such budgets would 

apply for conformity on the effective 

date of the Federal Register notice 

announcing EPA’s adequacy finding. 

During the grace period, areas can use 

earlier models such as PART5 for PM10

conformity determinations or choose to 

use MOBILE6.2 and AP–42 on a faster 

time frame. When the grace period ends 

on May 19, 2006, MOBILE6.2 will 

become the only approved motor 

vehicle emissions model for new PM10

transportation conformity analyses 

outside of California and AP–42 will 

become the approved method for 

estimating re-entrained road dust unless 

an alternate method is approved as 

described in section III above. In 

general, this means that all new PM10

conformity analyses started after the end 

of the 2-year grace period must be based 

on MOBILE6.2 and AP–42, even if the 

SIP is based on PART5. As discussed 

above, the grace period for new 

conformity analyses would be shorter 

for PM10 if an area revised its SIP and 

budgets with MOBILE6.2 and AP–42 

and such budgets became applicable for 

conformity purposes prior to the end of 

the 2-year grace period. EPA strongly 

encourages areas to use the consultation 

process to examine how MOBILE6.2 and 

AP–42 will affect future conformity 

determinations, so, if necessary, PM10

SIPs and budgets can be revised with 

MOBILE6.2 and AP–42 or transportation 

plans and programs can be revised as 

appropriate prior to the end of the grace 

period. 

Finally, the conformity rule provides 

some flexibility for analyses that are 

started before or during the grace 

period. Regional conformity analyses 

that began before the end of the grace 

period may continue to rely on earlier 

models such as PART5. Conformity 

determinations for transportation 

projects may also be based on an earlier 

model if the regional analysis was begun 

before the end of the grace period, and 

if the final environmental document for 

the project is issued no more than three 

years after the issuance of the draft 

environmental document (see 40 CFR 

93.111(c)). The interagency consultation 

process should be used if it is unclear 

whether an analysis based on an earlier 

model was begun before the end of the 

grace period. 

The release of MOBILE6.2 and AP–42 

does not trigger the need for quantitative 

conformity hot-spot modeling to 

estimate concentrations of PM10 at this 

time. However, qualitative hot spot 

analyses are still required in PM10

nonattainment and maintenance areas. 

VI. PM2.5 SIP and Transportation 

Conformity Policy for MOBILE6.2 and 

AP–42 

EPA has not yet finalized 

implementation policy for the PM2.5

National Ambient Air Quality Standards 

(NAAQS). However, when that policy is 

finalized and PM2.5 nonattainment areas 

have been designated, MOBILE6.2 

(except in California) and AP–42 (except 

in areas where another dust 

methodology has been approved) will be 

the approved models for estimating 

motor vehicle exhaust, brake and tire 

wear, and re-entrained road dust 

emissions in PM2.5 SIPs and conformity 

determinations, until they are replaced 

by newer models or methods. No PM2.5

SIPs have previously been done using 

other models and therefore, the release 

of MOBILE6.2 and AP–42 does not 

constitute a change in models which 

might result in inconsistencies between 

the SIP and transportation analyses. As 

a result, there is no need for a PM2.5

conformity grace period for MOBILE6.2 

and AP–42. MOBILE6.2 (except in 

California) and AP–42 (except in areas 

where another dust methodology has 

been approved) must be used in all 

PM2.5 conformity analyses, until they 

are replaced by newer approved 

methods or models.

Dated: May 11, 2004. 

Margo Tsirigotis Oge, 

Director, Office of Transportation and Air 

Quality.

[FR Doc. 04–11340 Filed 5–18–04; 8:45 am] 

BILLING CODE 6560–50–P

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 180 

[OPP–2004–0130; FRL–7359–1] 

Indoxacarb; Time-Limited Pesticide 

Tolerance

AGENCY: Environmental Protection 

Agency (EPA).

ACTION: Final rule.

SUMMARY: This regulation establishes a 

time-limited tolerance for residues/

combined residues of indoxacarb, (S)-

methyl 7-chloro-2,5-dihydro-2-

[[(methoxycarbonyl) [4-

(trifluoromethoxy) 

phenyl]amino]carbonyl] indeno[1,2-

e][1,3,4]oxadiazine-4a(3H)-carboxylate, 

and its R-enantiomer, (R)-methyl 7-

chloro-2,5-dihydro-2- 

[[(methoxycarbonyl)[4-

(trifluoromethoxy) 

phenyl]amino]carbonyl]indeno[1,2-

e][1,3,4]oxadiazine-4a(3H)-carboxylate, 

in or on cherry, sweet and cherry, tart. 

E.I. DuPont de Nemours and Company, 

DuPont Crop Protection requested this 

tolerance under the Federal Food, Drug, 

and Cosmetic Act (FFDCA), as amended 

by the Food Quality Protection Act of 

1996 (FQPA). The tolerance will expire 

on May 21, 2007.

DATES: This regulation is effective May 

19, 2004. Objections and requests for 

hearings must be received on or before 

July 19, 2004.

ADDRESSES: To submit a written 

objection or hearing request follow the 

detailed instructions as provided in 

Unit VIII. of the SUPPLEMENTARY

INFORMATION. EPA has established a 

docket for this action under Docket ID 

number OPP–2004–0130. All 

documents in the docket are listed in 

the EDOCKET index at http://

www.epa.gov/edocket. Although listed 

in the index, some information is not 

publicly available, i.e., CBI or other 

information whose disclosure is 

restricted by statute. Certain other 

material, such as copyrighted material, 

is not placed on the Internet and will be 

publicly available only in hard copy 

form. Publicly available docket 

materials are available either 

electronically in EDOCKET or in hard 

copy at the Public Information and 

Records Integrity Branch (PIRIB), Rm.