Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Notices 10849

Discussions are likely to involve disclosure

of investigative records compiled for law

enforcement purposes, or information which

if written would be contained in such

records, the disclosure of which would

interfere with enforcement proceedings.

Discussions are also likely to specifically

concern the Commission’s participation in a

civil action or proceeding or the conduct of

a particular case involving a determination

on the record after opportunity for a hearing.

The relevant exemptions on which this

certification is based are set forth in the

following provisions of law:

Section 552b(c) of Title 5 of the United States

Code, (7)(A), (10)

Section 375.205(a) of Title 18 of the Code of

Federal Regulations, (7)(i), (10)(ii)

Dated: February 19, 1997.

David N. Cook,

Deputy General Counsel.

[FR Doc. 97–5989 Filed 3–6–97; 11:27 am]

BILLING CODE 6717–01–M

ENVIRONMENTAL PROTECTION

AGENCY

[AMS–FRL–5699–8]

Air Pollution Control; Motor Vehicle

Emission Factors

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of public workshop.

SUMMARY: The Environmental Protection

Agency is now in the process of

developing revision and improvements

to the highway vehicle emission factor

model (the MOBILE model). The current

version of the model, MOBILE5a, was

released for use March 26, 1993. The

next version of the model, MOBILE6, is

tentatively planned for completion early

in 1998 and release for use in the

summer of 1998. This notice announces

the first public workshop for the

purpose of discussing issues raised by

the pending revisions to the model, and

provides the first formal opportunity for

comment and reaction to the plans for

data collection, analysis, and proposed

model revisions. There will be at least

one additional MOBILE6 workshop,

most probably to be held late this year.

The workshop will also include a short

presentation concerning EPA’s plans for

development of a nonroad mobile

source emission inventory model.

DATES: The workshop will be held

Wednesday, March 19 and Thursday,

March 20, 1997. The times are from 8:30

am to 5:00 pm March, and 8:30 am to

3:00 pm March 20. Al times are Eastern

Standard Time.

ADDRESSES: The workshop will be held

in Powsley Auditorium of the Morris

Lawrence Building, Washtenaw

Community College, 400 East Huron

River Drive, Ann Arbor, MI 48106.

Directions to the workshop can be

requested from the contact person listed

below, or from the EPA Technology

Transfer Network (TTN) bulletin board

system (BBS), or through accessing the

OMS World Wide Web (WWW) site.

Information on how to electronically

access this and other workshop-related

information appears immediately below.

FOR FURTHER INFORMATION CONTACT: Ms.

Betty Measley, U.S. EPA Office of

Mobile Sources, Assessment and

Modeling Division, Emission Inventory

Group, 2565 Plymouth Road, Ann Arbor

MI 48105. Telephone: (313) 741–7903;

fax (313) 741–7939.

SUPPLEMENTARY INFORMATION: This

notice, as well as related information

concerning the workshop, may be found

in the OMS section of the EPA TTN

BBS. To access this information using

the WWW:

http://www.epa.gov/OMSWWW/

models.htm

gopher:

gopher.epa.gov menus‰Offices:

Air:OMS

ftp: ftp.epa.gov Chg Dir‰pub/gopher/

OMS

For those directly accessing the TTN

BBS by modem connection:

TTNBBS Dial-in: (919) 541–5742 [Voice

help: (919) 541–5384]

Web access to TTN: http://ttnwww.

rtpnc.epa.gov

telnet: ttnbbs.rtpnc.epa.gov (for reading/

leaving messages)

ftp: ttnftp.rtpnc.epa.gov Chg Dir‰HDrive/OMS

Workshop-related files, including a

copy of this notice, a map showing the

location of WCC, and later additional

information as described in the body of

this announcement, will be found at the

OMS Section, Models & Utilities

Subsection

Under Section 130 of the Clean Air

Act Amendments of 1990, EPA is

required to review, and to revise a

necessary, the emission factors used to

estimate emissions of volatile organic

compounds (VOC), carbon monoxide

(CO), and oxides of nitrogen (NOX) from

area and mobile sources. In the case of

highway vehicles, emission factors for

these pollutants as a function of various

parameters are estimated using the

highway vehicle emission factor model,

commonly referred to as MOBILE. This

model, which was first developed in the

late 1970s, has been revised, updated,

and improved periodically since that

time to account for increasing data and

analyses concerning in-use emissions

performance of highway vehicles,

changes in vehicle and emission control

technology, changes in fuel

composition, strengthening of

applicable emission standards,

refinements to applicable test

procedures, and other items that affect

emission levels in use.

Section 130 of the Act requires that

this emission factor review, and revision

as needed, be performed at least every

three years. As noted above, the current

official version of the model,

MOBILE5a, was released in March 1993.

Since that time, one interim update to

the model has been developed,

MOBILE5alH, released in November

1995. While not involving revision and

update to the entire model, this version

and developed to address specific needs

on the part of emission factor users.

MOBILE5alH incorporated a number

of changes intended to improve the

ability of modelers, particularly States

and local/regional governments, in

estimating the benefits of various

innovative inspection and maintenance

(I/M) programs and to improve the

accuracy of modeling situations in

which such programs change over time

or different programs are applied to

different subsets of the covered fleet.

The time elapsed since the last

complete revision to the model and the

additional test data and analyses

available since that time warrant

another thorough update and revision to

the model. OMS plans significant

changes not only to the underlying

emission factor estimates, but to how

emissions factors are modeled to

account for things such as a separation

of start and running exhaust emissions,

roadway facility type, average traffic

speeds, and a number of other important

changes that will affect the input

information required to use the model

as well as the type of information

produced by the model. Thus, this first

MOBILE6 workshop will present an

overview of the more important model

revisions being planned. The tentative

agenda for this workshop is discussed

below. Other aspects of the modeling of

highway vehicle emission that are not

specifically included within the

following discussion may also be briefly

addressed in this workshop; however,

the agenda discussed below is intended

to illustrate the major areas of

discussion for the workshop.

The workshop being announced by

today’s notice will span two days. In an

effort to facilitate travel plans on the

part of attendees, a preliminary agenda

for the two days is presented below.

Note that the first day (March 19) is

largely devoted to ‘‘technical’’ issues

involved in updating and revising the

model, while the second part-day
10850 Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Notices

(March 20) is focused more on ‘‘user

changes,’’ meaning those revisions

planned that will affect the input data

requirements and file structure and

output changes. Many attendees will

likely want to be present for both

sessions, however, some may find that

they can limit their attendance to one or

the other days based on their specific

interests and needs.

Topics To Be Discussed on March 19

The first day of the workshop is

planned to include presentations on the

new facility-specific speed correction

cycles, start emissions and separation of

start from running exhaust emissions,

technology fractions for future model

years, the findings of the in-use

deterioration team, effects of fuel

oxygenates and sulfur content on

emissions, ‘‘real-time’’ diurnal

evaporative emissions, and revisions to

the modeling of emissions from heavyduty vehicles. Each presentation will be

followed by a short discussion/question

and answer period, and there should be

some time left at the end of the day for

more general open discussion of the

material that has been presented.

New Facility-Specific Driving Cycles

One area of concern with respect to

the accuracy of modeled emission

factors has been the methods used to

correct emission estimates based on the

Federal Test Procedure (FTP), intended

to represent overall urban area driving

and with an average speed of 19.6 mph,

for other average speeds. EPA is

designing a plan for a much different

approach to this issue that we hope to

include in MOBILE6, which should

both improve the accuracy of emission

estimates over the range of travel speeds

of interest and improve the integration

of emission factor modeling with

transportation planning and modeling.

This would represent a major departure

from the approach taken in previous

versions of the model, and will result in

significant changes to both the input

data requirements and output emission

factor estimates relative to earlier

versions.

Start Emissions and Separation of Start

From Running Emissions

MOBILE has used operating mode

fractions (describing the portion of

overall vehicle miles travelled (VMT) by

vehicles in cold-start, hot-start, or

stabilized operation) as an input to

provide exhaust emission factors in

grams per mile that include start

emissions. Based on the needs of the air

quality and transportation planning

communities and the availability of data

suitable for this type of analysis, EPA is

proposing to make two major changes in

this area: Provision of start emissions (in

grams per vehicle per start) and

stabilized running exhaust emissions (in

grams per mile) at the option of the

model user, and basing start emission

estimates on time that a vehicle has

been off (rather than simply ‘‘cold’’ and

‘‘hot’’ starts, start emissions will be

modeled as a function of time that

vehicles have been off, or ‘‘soak time’’).

Technology Fractions

Emissions from highway vehicles are

estimated on a fleetwide basis using

information on the fractions of each

model years’ fleet that use different

technologies (e.g., fuel delivery systems,

catalytic converter type). Projecting

future year emission requires that

projections of future technology

fractions by model year be included in

the MOBILE model. A contractor

working for EPA has developed such

estimates for future years, which will be

presented and discussed.

In-Use Deterioration Team Findings

A team within OMS has spent

considerable effort reexamining the

extent of and causes of in-use

deterioration, or the increase in

emissions over time as vehicles

accumulate mileage and components,

including emission control components,

age and degrade in performance. The

team has worked in cooperation with

the In-Use Deterioration Work Group of

the Mobile Source Technical Advisory

Subcommittee (a subcommittee to the

Clean Air Advisory Committee

established under the Federal Advisory

Committee Act). All available data on

in-use emissions performance over time

have been used in an attempt to better

quantify the extent of in-use emissions

deterioration. An overview of the

findings of the team to date, and some

of the potential implications for the

modeling of in-use deterioration of

emissions in MOBILE6, will be

presented and discussed at this

workshop.

Fuel Sulfur and Oxygenate Content

Effects

EPA has known for some time that

other aspects of fuel (gasoline)

composition, beyond volatility as

measured by Reid vapor pressure (RVP),

have an impact on emissions.

MOBILE5a included the ability for the

modeler to specify the effects of RVP,

and of oxygenate type (i.e., alcohol or

ether blends) and content (% by wgt),

on emissions. At this workshop,

information on revising and improving

the modeling of oxygenate type of

content on emissions, and on the

impacts of sulfur on emissions, will be

presented and discussed.

Onboard Diagnostic System Effects

With the introduction of second

generation onboard diagnostic systems

(OBD–II) to the light-duty fleet, EPA

needs to develop methods of modeling

the impact of these systems on reducing

in-use deterioration of both exhaust and

evaporative emissions, in both

inspection/maintenance (I/M) program

areas and non-I/M areas. Proposed

approaches to including such effects on

MOBILE6, based on part on previous

work by the California Air Resources

Board and recommendations made by

the Modeling Work Group of the Mobile

Source Technical Advisory

Subcommittee, will be presented and

discussed.

Heavy-Duty Vehicle Emission Estimates

The estimation of in-use emissions

from heavy-duty vehicles is complicated

by the fact that such engines are

regulated on a mass/work basis (grams

per brake horsepower-hour), while users

of emission factors generally need

emissions on a mass/activity basis (i.e.,

grams per mile). This necessitates the

use of conversion factors to adjust g/

bhp-hr emissions to g/mi. These

conversion factors will be updated for

MOBILE6. In addition, plans are to

expand the number of vehicle categories

for which specific emission factors are

estimated by the model, replacing

‘‘heavy-duty gas vehicle’’ and ‘‘heavyduty diesel vehicle’’ emission factors

with estimates specific to a number of

subcategories (e.g., by GVW class, with

buses treated separately), EPA’s plans

for revisions in these areas will be

presented and discussed.

Fleet Characteristics

In order to model emission factors for

the entire in-use fleet of highway

vehicles, information on the total

numbers of vehicles by vehicle type, the

registration distributions by age of each

vehicle type, and the annual mileage

accumulation rates by age of each

vehicle type are required. Wile modelers

often substitute locality-specific data for

the national data that is included in

MOBILE, particularly for registration

distributions by age, it is still important

for national modeling and estimation of

the impact of new rules, standards, and

test procedures to update these types of

information periodically. EPA has

retained a contractor to develop more

recent information on fleet

characteristics, including detailed

information on the various subclasses of

heavy-duty gas and diesel vehicles, and

buses, for use in MOBILE6. A progress
Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Notices 10851

report on results to date and plans for

incorporating such data into MOBILE6

will be presented and discussed.

Real-Time Diurnal Emissions

For gasoline-fueled vehicle types,

non-exhaust emissions are a significant

portion of total emissions of volatile

organic compounds (VOC). Nonexhaust, or evaporative, emissions

consist of diurnal emissions, hot soak

(trip-end) emissions, refueling

emissions, and running and resting

losses. Diurnal emissions, generated

during times that a vehicle is not being

driven and ambient temperatures are

increasing, have in the past been based

on data obtained during one-hour forced

heat builds, with the temperature

increase representative of an entire

eight-hour period being performed over

one hour. More recent testing has shown

that if the emissions are measured over

longer periods of time, more

representative of the rate and duration

of temperature increases actually

experienced by in-use vehicles, the

results are not the same. To improve the

accuracy of diurnal emissions estimates,

and to provide users with the ability to

better model emissions over shorter

periods of time than full days (e.g.,

airshed models typically require

emissions on an hour-by-hour basis),

MOBILE6 will incorporate so-called

‘‘real time’’ diurnal emissions estimates

and means of estimating such emissions

over shorter time periods and lesser

temperature increases characteristic of

such shorter times. Plans for

implementing this approach in

MOBILE6 will be presented and

discussed.

Liquids Leaks, Trip Characteristics

Plans are for the new version of the

model to have means of explicitly

accounting for, and estimating

emissions due to evaporation of, liquid

leaks of fuel. Modeling liquid leaks

explicitly in MOBILE would have an

impact on estimates for other

nontailpipe emission factors (diurnals,

hot soaks, running and resting losses),

as the presumption is that liquid leaks,

if and when encountered, have been

included within these other emission

source categories. All of these

evaporative emission estimates are

affected by trip characteristics, or travel

patterns, such as average number of

trips per day, miles per day, miles per

trip, and so forth. EPA plans to have

updated these trip characteristics in

MOBILE6 on the basis of analysis of

data obtained from instrumented

vehicles.

These are the main areas in which

presentations are planned for the first

day of the workshop. Results of test

programs and data analyses will be

presented where available, and in all

subject areas plans for additional work

and proposed revisions to the model’s

treatment of each area will be discussed.

Topics To Be Discussed on March 20

As noted above, the focus of the

presentations and discussion on the

second day of the workshop will be

more toward changes that impact the

input data requirements and file

structure and on proposed output

changes. The second day will also

include a presentation concerning EPA’s

plans for development of a nonroad

emission inventory model.

Inspection/Maintenance (I/M) Programs

and Credits

One of the more important aspects of

the model from the perspective of many

States and local/regional entities is the

modeling of the benefits of various types

of periodic I/M programs.

MOBILE5alH was released in 1995 to

provide an interim tool for use in

modeling certain types of tests and

combinations of programs that could not

be modeled adequately using

MOBILE5a. The increasing variety of

test types (e.g., idle tests, IM240 tests,

use of remote sensing devices in

conjunction with other I/M programs,

the ASM and BAR90 tests), the

tendency toward greater use of multiple

sets of cutpoints (based, for example, on

age of vehicle at time of test), and the

frequency with which a given area is

using more than one type of I/M

program, whether simultaneously or

sequentially, all suggest that there is a

need for changes in how the emission

benefits resulting from such programs

are estimated and reflected in MOBILE

emission factors. In MOBILE6, EPA is

considering significant changes to the

means by which credits for I/M

programs are modeled. EPA will present

proposals for changes in the modeling of

I/M programs for discussion and

comment.

Input/Output Structure Changes

In past updates to the MOBILE model,

EPA has made a strong effort to

maintain upward compatibility of input

data files used to run the model. That

is, a MOBILE4.1 input file, for example,

can be used to run MOBILE5a, although

some features of MOBILE5a have no

corresponding feature in MOBILE4.1.

This has been accomplished through

adding new options as either (i)

additional permitted values assigned to

existing control flags, or (ii) additional

optional variables appended to the end

(right side) of existing input file lines,

set up so that if they are missing (as

would be the case if an input file for an

older MOBILE version not having that

feature) this in interpreted as ‘‘new

option not to be included in modeling.’’

The extent of changes planned and

proposed for MOBILE6 are such that it

wil not longer be possible to maintain

this ‘‘upward compatibility’’ of input

files. The output files are also likely to

change significantly.

Because this is likely to be of great

interest of State and local/regional

modelers in particular, EPA will devote

one presentation to specifically

outlining all of the input and output

changes implied by the model revisions

noted above, as well as others not the

subject of specific presentations at this

workshop. This information is still in

the proposal stage, and the input of and

reaction from modelers at and after the

workshop will assist in determining the

precise nature of these changes in

MOBILE6.

Nonroad Model—Overview of Plans

The final presentation at the

workshop will not be directly related to

MOBILE6, but instead will present an

overview of EPA’s plans for the

development of a nonroad mobile

source emission inventory (as versus

emission factor) model. Current nonroad

inventory development practices are

based on EPA’s Nonroad Engine and

Vehicle Emissions Study (NEVES), done

under the 1990 Clean Air Act

Amendment requirements, and

‘‘Procedures for Emission Inventory

Preparation, Volume IV: Mobile Sources

(EPA–450/4–81–026d (revised), 1992).

In consideration of the increased

recognition of the importance of

emissions from nonroad sources in

terms of overall emissions and air

quality, and the considerable practical

difficulty of implmenting the current

guidance, EPA is planning to develop a

SIP-related nonroad emissions

inventory model to meet the needs of

the modeling audidence. EPA will

present its plans and proposals for

development of a nonroad mobile

source emission inventory model, and

will be especially interested in input

from workshop attendees as to their

needs and preferences for such a model.

Specifically, EPA would lke to know the

types of locality-specific input data (e.g.,

equipment populations) that users of

such a model would anticipate

developing and using in order to

customize nonroad emission inventories

for the geographic domain of interest.

Such information obtained at the

workshop will assist EPA in

determining the best approaches to use
10852 Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Notices

in a nonroad emission inventory model

to maximize its utility.

Additional Information

To the extent possible, EPA will post

material at the TTN BBS site described

under FOR FURTHER INFORMATION

CONTACT above in advance of the

workshop. Those planning to attend,

and those interested in following the

progress of workshop planning more

closely, should periodically visit the

workshop information site. For

example, some of the presentation

materials that will be used at the

workshop will be posted in advance to

facilitate discussion and comment at the

workshop.

Dated: February 28, 1997.

Mary D. Nichols,

Assistant Administrator for Air and

Radiation.

[FR Doc. 97–5884 Filed 3–7–97; 8:45 am]

BILLING CODE 6560–50–M

[FRL–5700–7]

National Advisory Council for

Environmental Policy and Technology

Information Impacts Committee; Public

Meeting

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of public meeting.

SUMMARY: Under the Federal Advisory

Committee Act, PL 92463, EPA gives

notice of a two-day meeting, of the

National Advisory Council for

Environmental Policy and Technology

(NACEPT) Information Impacts

Committee (IIC). NACEPT provides

advice and recommendations to the

Administrator of EPA on a broad range

of environmental policy issues. The IIC

has been asked to review information

requirements, and provide

recommendations on how to effectively

position information resources to

support new, comprehensive and longterm Agency initiatives. This meeting is

being held to commence development of

the committee’s recommendations to the

Agency.

DATES: The two-day public meeting will

be held on Tuesday, April 15, 1997 from

9:00 a.m. to 5:00 p.m. and Wednesday,

April 16, 1997 from 9:00 a.m. to 3:00

p.m. The meeting will be held at the

Channel Inn Hotel 650 Water Street,

SW., Washington, DC 20024.

ADDRESSES: Although time will be

limited, there will be opportunity for

public comment. Interested parties may

submit written materials or comments,

or may choose to address the committee

directly. In either case, requests for

participation must be submitted no later

than March 31, 1997 to Joe Sierra,

Designated Federal Officer, NACEPT/

IIC, U.S. EPA, Office of the Cooperative

Environmental Management (1601F),

401 M Street, S.W., Washington, DC

20460.

FOR FURTHER INFORMATION CONTACT:

Joseph Sierra, Designated Federal

Officer for the Information Impacts

Committee at 202–260–5839.

Dated: February 25, 1997.

Joseph A. Sierra,

Designated Federal Official.

[FR Doc. 97–5888 Filed 3–7–97; 8:45 am]

BILLING CODE 6560–50–M

[FRL–5700–6]

National Advisory Council for

Environmental Policy and Technology

Reinvention Criteria Committee; Public

Meeting

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of public meeting.

SUMMARY: Under the Federal Advisory

Committee Act, PL 92463, EPA gives

notice of a two-day meeting of the

National Advisory Council for

Environmental Policy and Technology

(NACEPT) Reinvention Criteria

Committee (RCC). NACEPT provides

advice and recommendations to the

Administrator of EPA on a broad range

of environmental policy issues. The

RCC has been asked to identify criteria

the Agency can use to measure the

progress and success of specific

reinvention projects and its overall

reinvention efforts; and to identify

criteria to promote opportunities for

self-certification, similar to the concept

used for pesticide registration. This

meeting is being held to provide the

EPA with perspectives from

representatives of state and local

government, academia, industry,

environmental organizations, and

NGOs.

DATES: The two-day public meeting will

be held on Wednesday, April 2, 1997

from 8:30 am to 5:00 pm and on

Thursday, April 3, 1997 from 8:30 am to

4:00 pm. The meeting will be held at the

Ramada Plaza Hotel Old Town, 901 N.

Fairfax Street, Alexandria, Virginia.

ADDRESSES: Materials, or written

comments, may be transmitted to the

Committee through Gwendolyn Whitt,

Designated Federal Officer, NACEPT/

RCC, U.S. EPA, Office of Cooperative

Environmental Management (1601–F),

401 M Street, SW, Washington, D.C.

20460.

FOR FURTHER INFORMATION CONTACT:

Gwendolyn Whitt, Designated Federal

Officer for the NACEPT Reinvention

Criteria Committee at 202–260–9484.

Dated: February 25, 1997.

Gwendolyn C.L. Whitt,

Designated Federal Official.

[FR Doc. 97–5890 Filed 3–7–97; 8:45 am]

BILLING CODE 6560–50–P

[FRI–5701–4]

National Drinking Water Advisory

Council, Small Systems Working

Group; Notice of Open Meeting

Under Section 10(a)(2) of Public Law

92–423, ‘‘The Federal Advisory

Committee Act,’’ notice is hereby given

that a meeting of the Small Systems

Working Group of the National Drinking

Water Advisory Council established

under the Safe Drinking Water Act, as

amended (42 U.S.C. S300f et seq.), will

be held on March 20 and 21, 1997 from

8:30 am to 5:30 pm, at the Channel Inn,

650 Water Street, S.W., Washington, DC

20024. The meeting is open to the

public, but due to past experience,

seating will be limited.

The purpose of this meeting is to

review and discuss options for how EPA

might implement the capacity

development and state affordability

information provisions of the Safe

Drinking Water Act Amendments of

1996. The meeting is open to the public

to observe. The working group members

are meeting to gather information,

analyze relevant issues and facts and

discuss options. Statements will be

taken from the public at this meeting, as

time allows.

For more information, please contact,

Peter E. Shanaghan, Designated Federal

Officer, Small Systems Working Group,

U.S. EPA, Office of Ground Water and

Drinking Water (4606), 401 M Street

SW, Washington, D.C. 20460. The

telephone number is 202–260–5813 and

the email address is

shanaghan.peter@epamail.epa.gov.

Dated: March 3, 1997.

Charlene Shaw,

Designated Federal Officer, National Drinking

Water Advisory Council.

[FR Doc. 97–5880 Filed 3–7–97; 8:45 am]

BILLING CODE 6560–50–M

[FRL–5701–5]

National Drinking Water Advisory

Council, Source Water Protection

Working Group; Notice of Open

Meeting

Under Section 10(a)(2) of Public Law

92–423, ‘‘The Federal Advisory