APPENDIX ONE 

Redesignation Guidance from U.S. EPA 
From: Dagostino.Kathleen@epamail.epa.gov

To: Hoch, Joseph A - DNR; 

CC: Aburano.Douglas@epamail.epa.gov; Mooney.John@epamail.

epa.gov; 

Subject: Re: Fw: Ozone Redesignation Questions

Date: Wednesday, February 18, 2009 4:05:22 PM

Attachments:

Hi Joe, 

It is likely that I will be writing the Federal Register notice for the 

Wisconsin areas, so I'd be happy to work with you on the redesignation 

requests. I have answered your specific questions below, but it might 

be useful to set up a call so that we can make sure all of the 

redesignation requirements are covered and I can answer any other 

questions you may have. I will be out of the office the rest of this 

week but will be back in the office on Monday and Wednesday next week. 

Let me know if either of those days work for you. 

Kathleen 

______________________ 

Kathleen D'Agostino 

Environmental Engineer 

U.S. EPA - Region 5 

Phone: (312) 886-1767 

email: dagostino.kathleen@eap.gov 

----- Forwarded by Douglas Aburano/R5/USEPA/US on 02/18/2009 09:53 AM 

----- 

 "Hoch, Joseph A 

 - DNR" 

 <Joseph.Hoch@wis 

 consin.gov> To 

 Douglas Aburano/R5/USEPA/US@EPA 
 02/18/2009 09:50 cc 

 AM 

 Subject 

 Ozone Redesignation Questions 

Hi Doug, 

I'm currently working on a redesignation request for our nine 

nonattainment counties and have a few questions for you. The current 

nonattainment counties include Door, Kenosha, Manitowoc, Milwaukee, 

Ozaukee, Racine, Sheboygan, Washington, and Waukesha. 

1. We intend to use the 2002 inventory for our nonattainment inventory, 

a 2007 inventory grown from the 2005 inventory for our attainment 

inventory, a projected 2012 inventory for our interim inventory, and a 

projected 2020 inventory as our maintenance inventory. Does this sound 

alright? It sounds fine. 

2. Do you have any recommendations for developing a 2020 inventory? 

The majority of available growth factors, such as the Pechan factors 

from LADCO, are only available until 2018. Would it be appropriate to 

switch growth factors after 2018 or do a linear interpolation? We need 

to use at least a 2020 inventory so the maintenance inventory is 10 

years following the EPA's redesignation determination. Linear 

interpolation is fine. 

3. Are we still to use the following guidance documents for the 

redesignation request: These guidance documents remain applicable. I 

can provide you with a list of other supporting guidance documents (also 

issued circa 1992-1994). 
- “Procedures for Processing Requests to Redesignate Areas to 

Attainment,” issued September 4, 1992, to EPA Regional Air Directors 

- A September 17, 1993 memo, "State Implementation Plan (SIP) 

Requirements for Areas Submitting Requests for Redesignation to 

Attainment of the Ozone and Carbon Monoxide (CO) National Ambient Air 

Quality Standards (NAAQS) on or after November 15, 1992" from Michael H. 

Shapiro to the EPA Regional Air Division Directors. 

- "Reasonable Further Progress, Attainment Demonstration, and Related 

Requirements for Ozone Nonattainment Areas Meeting the Ozone National 

Ambient Air Quality Standard" dated May 10, 1995 from John S. Seitz to 

the EPA Regional Air Division Directors. 

4. Has there been any updated redesignation guidance issued recently? 

No. 

Thank you for any information you can provide. 

Joe Hoch 

Air Pollution Control Specialist 

Bureau of Air Management 

Wisconsin Department of Natural Resources 

phone: (608) 264-8861 

e-mail: Joseph.Hoch@wisconsin.gov 
From: Dagostino.Kathleen@epamail.epa.gov

To: Hoch, Joseph A - DNR; 

CC:

Subject: RE: 1997 8-Hour Ozone Standard Redesignation Guidance

Date: Wednesday, April 01, 2009 10:57:31 AM

Attachments:

No problem. I probably won't get a chance to review your draft until 

next week though. Sorry. 

______________________ 

Kathleen D'Agostino 

Environmental Engineer 

U.S. EPA - Region 5 

Phone: (312) 886-1767 

email: dagostino.kathleen@eap.gov 

 "Hoch, Joseph A 

 - DNR" 

 <Joseph.Hoch@wis 

 consin.gov> To 

 Kathleen 

 04/01/2009 10:49 Dagostino/R5/USEPA/US@EPA 

 AM cc 

 Subject 

 RE: 1997 8-Hour Ozone Standard 

 Redesignation Guidance 
Thanks! 

-----Original Message----- 

From: Dagostino.Kathleen@epamail.epa.gov 

[mailto:Dagostino.Kathleen@epamail.epa.gov] 

Sent: Wednesday, April 01, 2009 10:48 AM 

To: Hoch, Joseph A - DNR 

Subject: Re: 1997 8-Hour Ozone Standard Redesignation Guidance 

Here they are. 

(See attached file: 11-30-1993 Maintenance Demo.pdf)(See attached file: 

4-30-1992 Maintenance Plans.pdf)(See attached file: 5-10-1995 Clean 

Data.pdf)(See attached file: 6-1-1992 Contingency Measures.pdf)(See 

attached file: 6-18-1990 Laxton.pdf)(See attached file: 8-17-1993 TSDs - 

Redes.pdf) 

(See attached file: 9-4-1992 Calcagni.pdf)(See attached file: 9-17-1993 

Shapiro.pdf)(See attached file: 9-28-1992 SIPs-CAA Deadlines.pdf)(See 

attached file: 10-14-1994 NSR Redesignation.pdf)(See attached file: 

11-16-1994 Limited Maintenance.pdf) 

______________________ 

Kathleen D'Agostino 

Environmental Engineer 

U.S. EPA - Region 5 

Phone: (312) 886-1767 

email: dagostino.kathleen@eap.gov 

 "Hoch, Joseph A 

 - DNR" 

 <Joseph.Hoch@wis 

 consin.gov> To 

 Kathleen 

 03/31/2009 01:09 Dagostino/R5/USEPA/US@EPA 

 PM cc 
 Subject 

 1997 8-Hour Ozone Standard 

 Redesignation Guidance 

Hi Kathleen, 

In an email dated February 18, 2009 you stated that you could provide me 

with a list of other supporting guidance documents (also issued circa 

1992-1994) besides the following four documents: 

- "Procedures for Processing Requests to Redesignate Areas to 

Attainment," issued September 4, 1992. 

- "State Implementation Plan (SIP) Actions Submitted in Response to 

Clean Air Act (Act) Deadlines," issued October 28, 1992. 

- "State Implementation Plan (SIP) Requirements for Areas Submitting 

Requests for Redesignation to Attainment of the Ozone and Carbon 

Monoxide (CO) National Ambient Air Quality Standards (NAAQS) on or after 

November 15, 1992," issued September 17, 1993. 

- "Reasonable Further Progress, Attainment Demonstration, and Related 

Requirements for Ozone Nonattainment Areas Meeting the Ozone National 

Ambient Air Quality Standard," issued May 10, 1995. 

Could you send me that list? I'm working on putting the EPA guidance 

appendix together for our redesignation request. 

Thanks, 

Joe 

1

Hoch, Joseph A - DNR

From: Doty.Edward@epamail.epa.gov

Sent: Wednesday, May 27, 2009 3:02 PM

To: Hoch, Joseph A - DNR

Cc: Rosenthal.Steven@epamail.epa.gov

Subject: RE: Nonpoint Controls

Hi Joe,

My reading of a May 30, 2007 EPA policy memorandum, "Emission Reduction Credit fo Three 

Federal Rules for Categories of Consumer and Commercial Products under Section 183(e) of 

the Clean Air Act", leads me to conclude that you can also apply 75 percent of the total 

possible VOC emission reductions expected for the expected AIM and consumer products rules

in 2007. The policy memorandum mentions "immediate" emission reduction credits and 

acknowledges that, of the date of the policy memorandum, some AIM coatings and consumer 

products were already complying with the expected emission reduction credits. This tells 

me that it is correct to assume the 75 percent crediting is also appropriate for 2007, as 

well as for 2008.

Unfortunately, EPA has yet to publish the final rules. Therefore, it is incorrect to take

100 percent of the emission reduction credits for 2009 and later. Until EPA completes the

promulgation and implementation of the rules, or the State has adopted and implemented its

own AIM and consumer products rules, it is not acceptable to assume that 100 percent of 

the possible emission reductions have been achieved. We would continue to accept the 75 

percent of possible emission reductions for the 2009 and post-2009 periods.

 Ed Doty

 

 "Hoch, Joseph A 

 - DNR" 

 <Joseph.Hoch@wis 

 consin.gov> To 

 Edward Doty/R5/USEPA/US@EPA 

 05/26/2009 02:42 cc 

 PM 

 

 Subject 

 RE: Nonpoint Controls 

Hi Ed,

I am developing a 2007 emissions inventory for our ozone redesignation request. I have a 

question for you regarding nonpoint emission reduction credits. This relates to the email

below from Grant Hetherington. What percentage of reduction would be acceptable for a

2007 emission inventory for the rules mentioned.
2

Thanks,

Joe Hoch

_____________________________________________

From: Hetherington, Grant D - DNR

Sent: Tuesday, May 26, 2009 1:19 PM

To: Hoch, Joseph A - DNR

Subject: Nonpoint Controls

Joe,

Here are the nonpoint controls that Ed Doty agreed to for the 2008 EI.

 a. For revised architectural and industrial maintenance (AIMS)

 coatings rule, take 75% of 31% (i.e. 23.25%) for a control factor.

 The reductions apply to 2401001000 and 2401100000.

 b. For revised household and institutional consumer products rule,

 take 75% of 29% (i.e. 21.75%) for a control factor. The

 reductions apply to 2460100000, 2460200000, 2460400000,

 2460500000, 2460600000, 2460800000 and 2460900000.

For 2007, you need ask Ed Doty about allowed controls. For 2010 on, you can assume that 

100% credit for the controls can be taken.

Grant
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

RESEARCH TRIANGLE PARK. NC 27711

I

\.

M,4YIO 1995

MEMORANDUM

OFFICE OF

AIR QUALITY PLANNING

AND STANDARDS

(MD-10)

John S. seitz, Directo

Office of Air Quality P

FROM:

SUBJECT: Reasonable Further Progress~

and Related Requirements for

Meeting the Ozone Nationa

TO: Director, Air, Pesticides and Toxics

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI .

Director, Air and Toxics Division,

Regions VII, VIII, IX, and X

I. policy

This memorandum sets forth EPA's interpretation of certain

requirements of subpart 2 of part D of title I of the Clean Air

Act as they relate to ozone nonattainment areas that are meeting

the ozone NAAQS. Specifically, it addresses whether such areas

must submit SIP revisions concerning reasonable further progress

and attainment demonstrations. The requirements at issue include

the 15 percent plan and attainment demonstration requirements of

section 182(b) (1) for moderate and above ozone nonattainment

areas and the attainment demonstration and post-1996 RFP

requirements of section 182(c) (2) for serious and above ozone

nonattainment areas. Related requirements include the moderate

ozone nonattainment requirements of section 172(c) (9) concerning

contingency measures, the serious ozone nonattainment area

requirements of section 182(c) (9) concerning contingency

measures, section 182(c) (5) concerning transportation control

measures and section 182(g) concerning milestones. They also

include the elements of the severe and extreme ozone

nonattainment area requirements of section 182(d) (1) (A)

concerning vehicle miles traveled that are related to RFP

requirements.
2

For the reasons described below, EPA believes that it is

reasonable to interpret these provisions so as not to require

areas that are meeting the ozone standard to make the SIP

submissions to EPA described in the provisions as long as the

areas continue to meet the standard. If such an area were to

monitor a violation of the standard prior to being redesignated

to attainment, however, the area would have to address the

pertinent requirements and submit the SIP revisions described in

those provisions to EPA. .

This memorandum also describes the process by which EPA will

determine that an area is attaining the ozone standard and need

not make these SIP submissions.

II. Interpretation and Legal Rationale

The EPA believes it is reasonable to interpret prov1s10ns

regarding RFP and attainment demonstrations, along with related

requirements, so as not to require SIP submissions if an ozone

nonattainment area sUbject to those requirements is in fact

attaining the ozone standard (i.e., attainment of the NAAQS is

demonstrated with 3 consecutive years of complete, qualityassured air quality monitoring data). The EPA has previously

interpreted the general provisions of subpart 1 of part D of

title I (sections 171 and 172) so as not to require the'

submission of SIP revisions concerning RFP, attainment

demonstrations, or contingency measures, and EPA believes it is

appropriate to interpret the ozone-specific provisions of subpart

2 in the same manner.

First, with respect to RFP, section 171(1) states that, for

purposes of part D of title I, RFP "means such annual incremental

reductions in emissions of the relevant air pollutant as are

required by this part or may reasonably be required by the

Administrator for the purpose of ensuring attainment of the

applicable NAAQS by the applicable date." Thus, whether dealing

with the general RFP requirement of section 172(c) (2), or the

more specific RFP requirements of subpart 2 for classified ozone

nonattainment areas (the 15 percent plan requirement of section

182(b) (1) and the 3 percent per year requirement of section

182(c) (2»,1 the stated purpose of RFP is to ensure attainment by

the applicable attainment date. If an area has in fact attained

the standard, the stated purpose of the RFP requirement will have

lEPA notes that paragraph (1) of subsection 182(b) is

ent,itled "PLAN PROVISIONS FOR REASONABLE FURTHER PROGRESS" and

that subparagraph (B) of paragraph 182(c) (2) is entitled

"REASONABLE FURTHER PROGRESS DEMONSTRATION,II thereby making it

clear that both the 15 percent plan requirement of section

182(b) (1) and the 3 percent per year requirement of section

182(c) (2) are specific varieties of RFP requirements.
(

3

already been fulfilled and EPA does not believe that the area

need submit revisions providing for the further emission

reductions described in the RFP provisions of section 182(b) (1)

and 182(c) (2) (B) and (C).

The EPA notes that it took this view with respect to the

general RFP requirement of section 172(c) (2) in the General

Preamble for the Interpretation of Title I of the Clean Air Act

Amendments of 1990 (57 FR 13498 (April 16, 1992», and it is now

extending thatlnterpretation to the specific provis'lons of

subpart 2. In the General Preamble, EPA stated, in the context

of a discussion of the requirements applicable to the evaluation

of requests to redesignate nonattainment areas to attainment,

that the "requirements for RFP will not apply in evaluating a

request for redesignation to attainment since, at a minimum, the

air quality data for the area must show that the area has already

attained. Showing that the State will make RFP towards

attainment will, therefore, have no meaning at that point" (57 FR

13564) .2

Second, with respect to the attainment demonstration

requirements of section 182(b) (1) and 182(c) (2), an analogous

rationale leads to the same result. section 182(b) (1) requires

that the plan provide for "such specific annual reductions in

emissions . . . as necessary to attain the primary NAAQS by the

attainment date applicable under this Act." Section 182(c) (2) (A)

simply requires a "demonstration that the plan, as revised, will

provide for attainment of the ozone NAAQS by the applicable

attainment date." As with the RFP requirements, if an area has

in fact monitored attainment of the standard, EPA believes there

is no need for an area to make a further submission containing

additional measures to achieve attainment. This is also

consistent with the interpretation of the section 172(c)

requirements provided by EPA in the General Preamble to title I,

as EPA stated there that no other measures to provide for

attainment would be needed by areas seeking redesignation to

attainment since "attainment will have been reached" (57 FR

13564; see also September 4, 1992 Calcagni memorandum).

other SIP submission requirements are linked with these

attainment demonstration and RFP requirements, and similar

reasoning applies to them. The first of these additional

2See also "Procedures for Processing Requests to Redesignate

Areas to Attainment," from John Calcagni, Director, Air Quality

Management Division, to Regional Air Division Directors,

September 4,1992, at page 6 (stating that the "requirements for

reasonable further progress . . . will not apply for

redesignations because they only have meaning for areas not

attaining the standard") (hereinafter referred to as "September

1992 Calcagni memorandum").
/ 4

requirements are the contingency measure requirements of section

172{c) (9) and section 182{c) (9). The EPA has previously

interpreted the contingency measure requirement of section

172{c) (9) as no longer being applicable once an area has attained

the standard since those "contingency measures are directed at

ensuring RFP and attainment by the applicable date" (57 FR 13564;

see also September. 4, 1992 Calcagni memorandum). Similarly, as

the section 182{c) (9) contingency measures are linked with the

RFP requirements of section 182{b) (1) and 182{c) (2), the

requirement of section 182{c) (gO) no longer applies once an area

has attained the standard.

other requirements related to the attainment demonstration

and RFP provisions include: (1) the section 182(c) (5)

requirement regarding the submission of a demonstration as to

whether various parameters related to transportation "are

consistent with those used for the area's demonstration of

attainment"; (2) the section 182{g) requirements concerning

milestones that are based on the section 182{b) (1) and

182(c) (2) (B) and (C) submissions; and (3) the elements of the

section 182(d) (1) (A) requirement for SIP revisions identifying

and adopting transportation control strategies to achieve

reductions in motor vehicle emissions that relate to the RFP

requirements of section 182(b) (1) (A) and 182(c) (2) (B). Inasmuch

as each of these requirements is linked with the attainment

demonstration or RFP requirements of section 182(b) (1) or

182(c) (2), if an area is not SUbject to the requirement to submit

the underlying attainment demonstration or RFP plan, it need not

submit the related SIP revision either.

The EPA emphasizes that this interpretation does not extend

to requirements of subpart 2 that are not linked by the language

of the Act with the attainment demonstration and RFP

requirements. For example, this interpretation does not apply to

requirements such as VOC RACT requirements, for which, in

contrast to NOx RACT requirements under section 182(f), the Act

does not establish a mechanism to grant exemptions if an area has

attained the standard, or to the requirements to submit SIP

revisions providing for basic or enhanced liM programs.

The EPA also emphasizes that the lack of a requirement to

submit SIP revisions concerning these RFP, attainment

demonstration, and other related requirements exists only for as

long as a nonattainment area continues to monitor attainment of

the standard. If such an area experiences a violation of the

NAAQS,the basis for the requirements not being applicable would

no longer exist. Therefore, the area would again be SUbject to a

requirement to submit the pertinent SIP revision or revisions and

would need to address those requirements. Thus, a determination

that an area need not submit one of the SIP submittals amounts to

no more than a suspension of the requirement for so long as the

area continues to attain the standard. If EPA ultimately
( 5

redesignates the area to attainment, then the area will be

entirely relieved of these requirements to the extent the

maintenance plan for the area does not rely on them.

Also, EPA notes that in the case of a multistate

nonattainment area, the entire multistate nonattainment area must

have monitoring data demonstrating attainment for the SIP

submission requirements to be suspended. Thus, the requirements

applicable to one part of such an area may not be suspended on

the basis of a determination only that that part of the

nonattainment area is monitoring attainment. The EPA's Regional

Offices should coordinate these determinations for any multistate

nonattainment ~reas that involve more than one Region.

III. Process

The EPA Regional Offices will conduct individual rUlemakings

concerning areas that have 3 consecutive years of clean air

quality monitoring data demonstratfng attainment of the ozone

standard to make binding determinations that the areas have

attained the standard and need not make whichever of the SIP

revisions discussed above are pertinent. Since EPA has the

relevant air quality data in its possession, no submission from a

State would be required to initiate this process. Howe~er, a

State would be free to submit a petition to the appropriate EPA

Regional Office to notify the office that it believes that a

certain nonattainment area is eligible for these determinations

on the basis of monitored attainment of the ozone NAAQS.

As noted above, these determinations would be contingent on

the existence of monitoring data for the·areas that continue to

demonstrate attainment. If EPA sUbsequently determines that an

area has violated the standard, the basis for the determination

that the area need not make the pertinent SIP revisions would no

longer exist. The EPA would notify the State of that

determination and would also provide notice to the pUblic in the

Federal Register. Such a determination would mean that the area

would thereafter have to address the pertinent SIP requirements

within a reasonable amount of time, which EPA would establish

taking into account the individual circumstances surrounding the

particular SIP submissions at issue.

The State must continue to operate an appropriate air

quality monitoring network, in accordance with 40 CFR part 58, to

verify the attainment status of the area. The air quality data

relied upon for the above determinations must be consistent with

40 CFR part 58 requirements and other relevant EPA guidance and

recorded in EPA's Aerometric Information Retrieval System (AIRS).

Determinations made by EPA in accordance with this

interpretation.would not shield an area from EPA action to

require emission reductions from sources in the area where there
6

is evidence, such as photochemical grid modeling, showing that

emissions from sources in the area contribute significantly to

nonattainment in, or interfere with maintenance by, other

nonattainment areas. The EPA has authority under the Act

(section 110{a) (2) (D) in the case of areas in other states and

section 110{a) (2) (A) in the case of intrastate areas) to require

emissions reductions if necessary and appropriate to deal with

transport situations.

IV. Consequences for Redesiqnations, Sanctions, and Conformity

Determinations made by EPA that an area has attained the

NAAQS and need not make one or more of the SIP submissions

discussed above is not equivalent to the redesignation of the

area to attainment. Attainment of the standard is only one of

the criteria set forth in section 107(d) (3) (E) that must be

satisfied for an area to be redesignated to attainment. To be

redesignated, the State must submit and receive full approval of

a redesignation request for the area that satisfies all of the

criteria of that section, including the requirement of a

demonstration that the improvement in the area's air quality is

due to permanent and enforceable reductions, and the requirements

that the area have a fully-approved SIP which meets all of the

applicable requirements under section 110 and part D, and a

fully-approved maintenance plan. '

If an area for which the determination of attainment is made

has submitted or subsequently submits a redesignation request,

the SIP submissions discussed in this memorandum would not be

required for the area's redesignation request to be approved

since they would no longer be considered applicable requirements

under section 107{d) (3) (E). If the area violates the standard

prior to final action on the redesignation request, however, not

only would the requirements again become applicable, but the

redesignation request could not be approved because the area

would no longer meet the criterion of having attained the

standard.

As a consequence of a determination that an area has

monitoring data demonstrating attainment of the ozone standard,

thereby removing, at least temporarily, the pertinent SIP

submittal requirements discussed above, any sanction clock that

had been started as a consequence of the failure to make such a

sUbmission, the incompleteness of such a submission, or the

disapproval of such a sUbmission, would be stopped since the

deficiency that had led to the starting of the clock would no

longer exist.

The issuance of a determination pursuant to this pOlicy will

have no immediate impact on the way conformity is demonstrated.

Areas will continue to demonstrate conformity using the build/nobuild test and less-than-1990 test (section 51.436-51.446 of the
I

(

7

conformity rule), and the 15 percent SIP if one has been

submitted (and attainment/RFP SIP, if one with a budget has been

sUbmitted) .

Since areas that are the sUbject of determinations pursuant

to this policy will not be required to submit RFP or attainment

demonstration SIP's, those areas will not generally be in the

control strategy period for conformity purposes (i.e., have a

control strategy SIP approved and build/no-build test no longer

required) for so long as the area aoes not violate the standard.

Those areas will not generally have approved budgets until a

maintenance plan is approved as part of the approval of a

redesignation request, so the build/no-build test and less-than1990 test--in addition to any applicable submitted budgets--will

be required until then. (A maintenance plan budget does not

apply for conformity purposes until the maintenance plan has been

approved, except as provided by section 51.448(i) of the

conformity rule (which applies to areas that are required to

submit a 15 percent SIP but submit a maintenance plan instead).)

If an area receiving a determination pursuant to this policy

had previously submitted a 15 percent or attainment SIP, it may

choose to withdraw the submitted SIP through the submission of a

letter from the Governor or his or her designee in order to

eliminate the applicability of its motor vehicle emission budget

for conformity purposes. This is because that area would not be

sUbject to the 15 percent and attainment demonstration

requirements of section 182(b) (1) for so long as the area

continues to attain the standard. If the submitted SIP is not

withdrawn, the budget in that submission will continue to apply

for conformity purposes. If the submitted 15 percent or

attainment SIP is withdrawn, only the build/no-build and lessthan-1990 tests would apply until a maintenance plan is approved.

However, areas that are already demonstrating conformity to

a submitted maintenance plan pursuant to section 51.448(i) may

continue to do so, or may elect to withdraw the applicability of

the submitted maintenance plan budget for conformity purposes

until the maintenance plan is approved. The applicability may be

withdrawn through the submission of a letter from the Governor or

his or her designee. If the applicability of the submitted

maintenance plan budget is withdrawn for conformity purposes, the

build/no-build and less-than-1990 tests will apply until the

maintenance plan is approved.

For areas which receive a determination pursuant to this

policy and whose conformity status has lapsed due to a failure to

submit a 15 percent SIP or to the submission of an incomplete 15

percent SIP without a protective finding, the lapse imposed by

section 51.448(b) and (c) (1) (ii) will be removed. However, the

conformity status of the plan and TIP cannot be restored if
/

(

8

conformity has lapsed for any other reason (e.g., failure to

redetermine conformity by a certain date).

If you have any questions, please feel free to call me or

Sally Shaver. The contact persons for this policy are Carla

Oldham at (919) 541-3347 and Kathryn Sargeant at (313) 668-4441

for transportation conformity requirements.

cc: Rob Brenner

Alan Eckert

Tom Helms

Phil Lorang

Rich Ossias

Margo Oge

Joe Paisie

John seitz

Sally Shaver

Lydia Wegman

Dick Wilson
I·

C"

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

Office of Air Quality Planning and Standards

Research Triangle Park, North Carolina 27711

NOV 161994

MEMORANDUM

SUBJECT:

FROM:

, TO:

Limited Maintenance Plan option for Nonclassifiable

o~,-el ~o~at~reas'

s~~aver, Director

Air Quality Strategies & Standards,Division (MO-15)

Director, Air, Pesticides and Toxics

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director,- Air and Toxics Division,·

Regions VII, VIII, IX, and X

I. Purpose

This memorandum sets forth new guidance on maintenance plan

requirements for certain nonclassifiable ozone nonattainment

areas seeking redesignation to attainment.· In particular,

nonclassifiable ozone areas whose design values are at or below

0.106 ppm (85 percent of exceedance levels of the ozone NAAQS) at

the time of redesignation may choose to submit a less rigorous

maintenance plan than was formerly required. This new option is

being termed a limited maintenance plan. Nonclassifiable ozone

areas with design values greater than 0.106 ppm will continue to

be sUbject to full maintenance plan requirements described in the

September 4, 1992 memorandum, "Procedures for Processing Requests

to Redesignate Areas to A'Ctainment," from John calcagni, former

Director of the OAQPS Air Quality Management Division to the

Regional Air Division Directors.

There are three types of nonclassifiable ozone· areas:

sUbmarginal, transitional, and incomplete/no data. A description

of these areas is included as Attachment A.
2

( II. Background

section 107(d) (3) (E) of the Act provides that a

nonattainment area can be redesignated to attainment if the

following criteria are met:

,i

1. The -EPA has-determined that the "NAAQS for the "applicable

pollutant has been attained.

2. The applicable implementatiori plan has been fully

adopted under section 110(k).

3. The EPA has determined that the improv.ement in air.

quality is due to permanent and enforceable reductions in

emissions.

4. The state- has met all app"licable requirements" for the

area under section 110 and part D.

5. The EPA has fully approved a-maintenance plan, including

a contingency plan, for the area under section 175A.

section 175A- of- the Act _provides the -genera-I-framework· for . maintenance· plans. The maintenance plan must provide for

maintenclnce of-th-e-"-NAAQSfor- at-lea-st--lo-yearsafter - - - --- ---

redesignation,-t- -including -any additional control measures as -may --- be -necessary -to-.:.ensure- such maintenance. I"n addition,

maintenance plans are to contain such contingency provisions as . EPA deems necessary to- assure the prompt correction ·of a _

-violation of the NAAQS that occurs-after redesignation.The

-contingency measures must include, at a minimum, a requirement

that the·State.wil1 implement all control measures contained in

the nonattainment SIP prior to redesignation.

Beyond these requirements, however, section 175A does not

define the content of a maintenance plan. Thus, EPA has the

authority to exercise reasonable discretion to determine those

requirements. The EPA has previously issued guidance on meeting

all five criteria for redesignation including maintenance plans

(see Attachment B). The EPA now believes that it is justifiable

and appropriate to apply a djfferent set of maintenance plan

requirements (described herein) to a limited category of ozone

nonattainment areas--nonclassifiable areas whose monitored air

quality is equal to or less than 85 percent of exceedance levels

of the ozone NAAQS. The EPA does not believe that the full

maintenance plan requirements need be applied to these areas

because they have achieved air quality levels well below the

'Section l75A also requires that 8 years after

redesignation, the State must submit an additional plan to

provide for maintenance for a second follow-on lO-year period.
(:

3

standard without the application of control measures required by

the Act for classified ozone nonattainment areas. Also, these

areas do not have either a recent history of monitored violation

of the ozone NAAQS or a long prior history of monitored air

quality problems. The EPA believes that the continued

applicability of prevention of signif~cant deterioration (~SD)

requirements, any control measures already in the SIP, and

Federal measures (such as the Federal motor vehicle control

program) should provide adequate 1assurance of maintenance for

these areas.

III. Qualifying for the Limited Maintenance Plan option . .

To qualify for the limited maintenance plan option, the

ozone design value for the a~ea, based on the 3 years of data

used to demonstrate attainment, must be at or below 0.106 'ppm

(85 percent of exceedance·levels·of the-·ozone-NAAQS)-~-·-· ---' .. - Additionally, the design value for the area must continue to be

at or below 0.106 ppmunti-l thetimeo·f f·i-nal--EPA action· on-theredesignation. The method for calculating design values is

presented in the June_ 18, 1990.memorandum,_ "Ozoneand.Carbon

Monoxide Design Value Calculations," from William G. Laxton,

former Director of the ·OAQPSTechnical Support-~Division-to

Regional Air Directors• The memorandum ·focuses--primarily on

determining design values for nonattainment areas in order to

classify the areas as. marginal, moderate, -serious, severe, or

extreme. Therefore,--.the document discusses determining the

design value for an a-reabased on the monitors .which· are '.

exceeding the standard. _In the case of a nonattainment area

seeking redesignation to attainment, all monitors must be meeting

the standard. To assess whether a nonclassifiable area meets the

applicability cutoff for the limited maintenance plan, a separate

design value must be developed for every monitoring site. The

highest of these design values is the design value for the whole

area. If the area design value is at or below 0.106 ppm, the

State may select the limited maintenance plan option for the

first 10-year maintenance period. If the design value for the

area exceeds 0.106 prior to final EPA action on the

redesignation, the area no longer qualifies for the limited

maintenance plan and must instead submit a full maintenance plan.

The EPA will issue guidance in the future on the applicability of

the limited maintenance plan option to the second follow-on 10-

year maintenance period.

IV. Limited Maintenance Plan Elements

Following is a list of core provisions which should be

included in a limited maintenance plan. Any final EPA

determination regarding the adequacy of a limited maintenance

plan will be made following review of the plan submittal in light

of the particular circumstances facing the area proposed for

redesignation and based on all relevant available information.
c~·

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a. Attainment Inventory

The state should develop an attainment emissions inventory

to identify a level of emissions in the area which is sufficient

to attain theNAAQS. This inventory should be consistent with

EPA's most recent guidance2 on emissio~s inventories for _ nonattainmentareas avaiiable at the time and should represent

emissions during the time period-associated with the monitoring

data showing attainment. The inventory should be based on actual

"typical summer day" emissions of VOC'and NOx (ozone precursors).

Emissions of CO are not necessary in the attainment inventory

because they will not be tracked for maintenance purposes.

b. Maintenance Demonstration

The maintenance demonstration.requirement is considered to

be-satisfied for--nonclassifiable-areas--if-the-mon±toring data -- --- --- --- show the area is meeting·the air quality criteria discussed

·above.. There is· -no- requirement to- project-emissions over the .... --.- . -- ----- maintenance period. The EPA believes if the area begins the

maintenance period.'at- or below. as. percent of- .exceedancelevelsr .

the air quality along with the continued applicability of PSD

requirements, ·any control measures'already in the SIP, and

Federal measures, should provide adequate-assurance of

maintenance over the initial 10-year-maintenance period.

When EPA approves a limited maintenance·plan, EPA is

concluding that ·an· emissions budget:may -.be .treated as essentially

not constraining for the length of ·the maintenance period because

it is unreasonable to expect that··such -an area will experience so

much growth in. that period that a violation of the ozone NAAQS

would result.

c. Monitoring Network/Verification of continued Attainment

To verify the attainment status of the area over the

maintenance period, the maintenance plan should contain

provisions for continued operation of an appropriate, EPAapproved air quality monitoring network, in accordance with 40

CFR part 58. This is particUlarly' important for areas using a

limited maintenance plan bec~use there will be no cap on

emissions. .

2The EPA's current guidance on the preparation of emissions

inventories for ozone areas is contained in the following

documents: "Procedures for the Preparation of Emission

Inventories for Carbon Monoxide and Precursors of Ozone: Volume

I" (EPA-450/4-91-016), "Emission Inventory Requirements for Ozone

State Implementation Plans" (EPA-450/4-91-010), and "Procedures

for Emission Inventory Preparation: Volume IV, Mobile Sources"

(EPA-450/4-81-026d) .
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d. contingency Plan

section 175A of the Act requires that a maintenance plan

include contingency provisions, as necessary, to promptly correct

any violation of the NAAQS that occurs after redesignation of the

area. These contingency ~easures do ~t have to be fully adopted

at the time of redesignation. However, the contingency plan is

considered to be an enforceable part of the SIP and should ensure

that the contingency measures are~adopted expeditiously once they

are triggered by a specified event. The contingency plan should

identify the measures to be promptly adopted and provide a

schedule and procedure for adoption and implementation of the

measures. The State should also identify specific indicators., or

triggers, which will be used to determine when the contingency

measures need to be implement~d. While a violation of the NAAQS

is an acceptable trigger, States may wish to choose a previolation action level as a trigger, such as an exceedance of the

NAAQS. By taking early action, a State may be able to prevent

any actual violation -of -the NAAQS -and, there-fore," eliminate any

need on the part of EPA to redesignate an area back to

nonattainment.

v. Conformity Determinations Under Limited Maintenance Plans

The transportation conformity rule (58 FR 62188;

November 24, 1993) and the general conformity rule (58 FR 63214;

November 30, 1993) apply to nonattainment areas and maintenance

areas operating under maintenance plans. " Under either rule,' one

means of demonstrating"conformity of Federal actions· is to . indicate that expected emissions from planned actions are

consistent with the emissions budget for the area. As discussed

above in section IV(b) , emissions budgets in limited maintenance

plan areas may be treated as essentially not constraining for the

length of the initial maintenance period because it is

unreasonable to expect that such an area will experience so much

growth in that period that a violation of the ozone NAAQS would

result. In other words, EPA would be concluding that emissions

need not be capped for the maintenance period. Therefore, in

areas with approved limited maintenance plans, Federal actions

requiring conformity determinations under the transportation

conformity rule could be con~idered to satisfy the "budget test"

required in sections 93.118,'93.119, and 93.120 of the rule.

Similarly, in these areas, Federal actions subject to the general

conformity rule could be considered to satisfy the "budget test"

specified in section 93.158(a) (5) (i) (A) of the rule.

For further information regarding the limited maintenance

plan option for nonclassifiable ozone areas, please contact Carla

Oldham at (919) 541-3347. For information regarding

transportation conformity requirements, please contact Kathryn

Sargeant of the Office of Mobile Sources at (313) 668-4441. For
6

(.... information regarding general conformity requirements, please

contact Doug Grano at (919) 541-3292.

Attachments

...

..
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ATTACHMENT A

The EPA used 1987-89 as the primary data years in

determining designations and classifications for ozone areas set

forth in the November 6, 1991 final rule on Air Quality

Designations and Classifications (56 FR 56694) . certain ozone

nonattainment areas could not be classified as marginal or above

under Table 1 of section 18I(a) (1) of~the Clean Air Act either

because of- incomplete monitoring data-or because they were

nonattainrnent pre~enactment but did not violate the standard

during 1987-89. These areas are·collectively called

nonclassifiable areas. Nonclassifiable ozone areas consist of

transitional, submarginal, and incomplete/no data areas.

Transitional areas

An area is considered t~ansitional under section 185A if it

was designated nonattainment both prior to enactment and at the

time of enactment,-and did not-violate the primary NAAQS for

ozone over the 3-year period from 1987-1989.

section 185A of the Act required EPA to make a

determination, by June 30, 1992, whether the designated

transitional areas had continued to meet the ozone NAAQS through

December 31, 1991. - All 12 transitional areas were attaining the

NAAQS through December 31, 1991 and none are known to have

-violated the standard since. In May-and June of 1992; Regional

Administrators sent letters to Governors of States with -transitional areas notifying them of EPA's determination.

Submarginal areas

compliance with -the ozone NAAQS is determined on the basis

of expected exceedances which include an adjustment for missing

data.! The submarginal category includes areas that violated the

ozone NAAQS during 1987-89 but had a design value for the period

of less than .121 ppm (the lower limit for marginal areas) due to

the adjustment for missing data when calculating expected

exceedances. Presently, there are no submarginal areas.

Incomplete/no data areas

certain ozone areas designated nonattainment prior to - enactment and at enactment aid not have sufficient air quality

monitoring data to determine whether they were or were not

violating the NAAQS. These areas are termed incomplete/no data

areas. These include areas which do not have monitors.

Currently, there are 47 incomplete/no data areas.

IThis adjustment procedure is described in 40 CFR part 50.9,

appendix H.
· '

ATTACHMENT B '.

(' The EPA policies for implementing sections 107 and 175A of

the Act for redesignations are contained in the following'

memorandums.

1. "Procedures for .processing Re,quests to Redesignate Areas

to Attainment," John Calcagni, Director, Air Quality Management

Division, September 4,1992.

2. "State Implementation Plan (SIP) Requirements for Areas

SUbmitting Requests for Redesignation to Attainment of the Ozone

and Carbon Monoxide (CO) National Ambient Air Quality Standards

(NAAQS)on or after N·ovember· ~5, 1992,-" Michael Shapiro, ·:Acting

Assistant Administrator for Air and Radiation, September 17,

1993.

3. "State Implementation Plan (SIP) Actions·Submitted in

Response to Clean Air Act (CAA) Deadlines," John Calcagni,

.Director, Air. Quality Management Division, October 28,1992.

4. "Contingency Measur.es_for Ozone and.Carbon.Monoxide (CO)

Redesignations," G.T. Helms, Chief, Ozone/Carbon Monoxide

Programs Branch, June 1, 1992.

5. "General Preamble· for the Implementation of Title I of

the Clean Air Act Amendments of 1990" (57 FR 13498; April·16,

1992) •
57

•

UNITED STATES ENVIRONMENTAl PROTECTION AGENCY

WASHINGTON, D.C. ~O .

orRCE OF

AM AND MDlATJON

MEMORANDUM

.SUBJECT: Part D New Source Review (part D NSR) R.quirements for

Areas Recntestinq Rec1esignation to Attainment .

FROM: Nichols. ~1('~t Admini tor

'tor Air and Radiation (6101)

•

I. Introduction

TO: Director, Air, Pes~icides and Toxics

Management Division, Regions I and IV

Director, Air and Waste Management D~vision,

Region II .

Director, Air, Radiation and Toxies Division,

Region III .

Oirector, Air and Radiation Division, . Region V .

Director, Air, Pesticides and Toxies Division

Region VI

Director, Air and Toxies Division,

Regions VI~, VIII, IX, and X

with this memorandum, EPA is amending one aspect of guidance

issued september 4, 19921 and september 17, 19932 regarding

requirements for nonattainment areas requesting redesignation to

attainment. In these previous memoranda, EPA indicated that

states must submit and receive full approval of any part D NSR

regulations that were req~ired by the Act to be sUbmitted ta EPA

prior to or at the time of the submission of a complete

redesignation request. The EPA has'reconsidered that policy,

however, and is establishing a new policy under which

IMemorandum entitled, "Procedures for Processing Requests to

Redesignate Areas to Attainment, II from John Calcagni, Director;·

Air Quality Management Division, to Regional Air Division

Directors.

2Memorandum entitled, "SIP Requirements for Areas Submitting

Requests for Redesignation to Attainment of the Ozone and CO

NAAQS On or After November 15, 1992," from Michael H. Shapiro,

Acting Assistant Administrator for Air and Radiation, to Regional Air Division Directors.

•

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nonattainment areas may redesignated to attainment

notwithstanding the lack of a fully-approved part D NSR program,

provided the program is not relied upon for maintenance. In

addition, EPA is not requiring that existing part 0 NSR rules be

placed in the-contingency portion of the maintenance plan

pursuant to section 17SA ot the' Act. As discussed below,' , however, EPA believes it$ new policy will assure that the

statutory goals o~ part 0 NSR and section 17SA to protect"ana :maintain the NAAQS are achieved. -

The EPA

the Agency's

to statutory

requirements

(See Alabama

1979) .]

believes that this new policy is justifiable under

general authority to establish de minimis exceptions

requirements where the application of the statutory

would be of trivial or no value environmentally.

Power Co. v. Costle, 636 F.2d 323, 360-61 (D.C. Cir.

"

•

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II. BacKground/Clean Air Act Requirements

Section 107(d) (J)(E) of the Act requir~s that a state have

in place a fully-approved SIP meeting all the requirements

applicable to a nonattainment area under section 110 and part ,0

of title I ot the Act in order for the area to be redesignated to

attainment•

, In addition, section 175A requires that the area must have a

fUlly-approved.maintenance plan containing contingency

provisions, as necessary, to promptly correct any violation of

the applicable NAAQS that occurs after redesignation of the area.

At a minimum, the contingency plan must "include a requirement

that the state will implement all measures with respect to the

control of the air pollutant concerned which were contained in

the state implementation plan for the area before redesignation

of the area as an attainment area."

The NSR requirements are contained in section 110(a) (2)(C)

and in parts C'~nd 0 of title I of the Act. Broadly speaking,

section 110(a) (2) (C) of the Act mandates the development of a

preconstruction review program to assure that the construction or

modification of any stationary source is consistent with

attainment of the NAAQS. The nonattainment NSR program in part 0

NSR and the attainment area prevention of significant

deterioration (PSO) program in part C apply to major new sources

and modifications of existing major sources. (Implementing . regUlations that set forth minimum requirements for state or

local programs and Federal permitting programs have been

promulgated at 40 CFR part 51 SUbpart I and appendix S, and 40

CFR section 52.21, respectively.)

To assure'that major new or modified sources do not

interfere with reasonable further progress towards attainment,

nonattainment area part D NSR requires installation of control

,.. ... "
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,technology representing the lowest achievable eais.ions rate (LAE.~) and emission offsets. To prevent "clean air" areas from

significant degradation, the PSD program requires in.tallation of

best available control technology (BACT) and modeling to show

that the new ormodi~ied source will not cause or contribute to

violation ot a NAAQS or.a PSO air quality growth ~ncremen~.

Previously, EPA interpreted these provisions tovether."to-.

~equire that any area seeking redesignation to attainment ~ust

have ~ully-approved part 0 NSR rules as part o~ the required fully-approved SIP. In addition, upon ~edesignation, the part 0

NSR rules were to be placed in the maintenance plan contingency

provisions in accordance with section 175A of the Act unless the

area needed to continue implementing part 0 NSR as one element of

the maintenance strategy_

III. NSR Policv and Legal Rationale

The EPA now believes that a de minimis exception.to the

requirement of section 1~7(~U~)(E) ~or part 0 NSR 1. justi~iAble

because requiring the adoption and full approval of • part 0 NSR

program as a prerequisite to redesignation would not be of . signi~icant environmental value in certain circumstances. The

EPA has reconsidered its ear~ier posit~on because, once an area ' is redesiqnated to attainment, the part 0 NSR proqrq py be.

replaced by the corollary 'PSDproqram', if it is shown through the

maintenance demonstration that the area will maintain without

part 0 NSR and because part 0 NSR need not become partot··the

contingency plan. . .

A. Preconstruction Review Programs in Attainment: "Areas "

There are several provisions in the Act and in EPA'S

regulations that require preconstruction review of new or

modified major sources in attainment areas to assess the impact

of the proposed emissions increases on the applicable NAAQS.

These include the PSO program which covers 100 ton per year (tpy)

or 250 tpy or greater sources (depending on the source category),

the preconstruction review requirements of 40 CFR Sl.165(b) that

cover 100 tpy or greater sources, and the Interpretive offset

Rule. As to ozone, there are some partiCUlar requirements that

apply. The EPA believes these programs will ensure that major'

new sources and modifications are given adequate preconstruction

review.

After redesignation to attainment, state PSD rUles, or

Federal PSD rules in a delegated program, must ensure, as

required by sections 165(a) (3)(B) and 110(a) (2) (C) of the Act,

that preconstruction review of new and modified major sources

will prevent increases in emissions that would cause or

contribute to violations of the NMQS. [See 40 CFR 51. 166 (k), 40

CFR 52.21 (k) • J

1501

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In addition, EPA's regulations at 40 CFR 51.165(b) require

that SIP's contain preconstruction review requirementa that

apply to new or modified 100 tpyor greater sources ot a

pollutant in areas designated attainment or unclassifiable for

the pOllutant.in cases where the new or modified source would

contribute to a violation of a NAAQS. This requirement provides

for preconstruction review for sources that are exempt from PSD

due to PSD's higher (250 tpy) major source threshold tor certain

source categories. , .

In the absence of SIP provisions that comply with 40 CFR

51.165(b) or a part D NSR program, States would have to use the

Interpretive Offset Rule at 40 CPR Sl appendix S as a surrogate

rule for permitting new and modified major sources in these

attainment areas. (See 45 FR 31310, May 13, 1980.)

For so" PH-l0, N01 , and CO, EPA has established levels of

ambient impacts to determine whether the major new or modified

source would cause or contribute to a violation: Where the

source is found to cause or contribute to aViolation~ the source

would be sUbj ect··to Dlore stringent technology and emiSsions

mitigation requirements of appendix S or a 40 CFR 5l.165(b)

program.

With particular respect to ozone, because ot the difficulty

in modeling the impact··of emissions from specific sources on

ozone formation, EPA regulations [40 CFR Sl.16S(b) (3) and

appendix S] do not fully address how emissions of ozone

precursors shou~d be treated to assure that major new or modified

sources do not cause or contribute to a NAAQS violation.

Nevertheless·, if preconstruction monitoring or other intormation

indicates the area is not continuing to meet the standard after

redesignation to attainment, appendix S or a 40 eFR Sl.16S(b)

program would also apply. The EPA believes that in any area that

is designated or redesignated as attainment under section 107,

but experiences violations of the NAAQS, these provisions· (and

any implementing SIP provisions) should be interpreted as

requiring major new or modified sources to obtain voe emission

offsets of at least a 1:1 ratio, and as·presuming [consistent

with section 182(f») that 1:1 NOx off~ets are necessary.)

In addition, attainment (PSO) plans require that major new

and modified sources apply BACT. Generally, BACT differs from

LAER by enabling permitting authorities to justify, based on

)The EPA is in the process of revlslng EPA's rules for NSR

and PSD, some of which will replace appendix S. However, the

proposed revisions will not change the substantive permitting

requirements where an attainment area is violating the ozone

NAAQS.

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5

economic, energy, and environmental impacts, the u•• of control

technologies less e~fective than the most stringent available.

In an area that is not meeting the NAAQS, EPA believes that due

to consideration'ot the NAAQS violations, the state may impose a

more stringen~ level of control than might be otherwise selected

as BACT. (See Draft New Source Review Manual, page 8. 54 (,october 1990).) .

". .. Taken together, these preconstruction review programs can

','assure that major new or 1Iodified sources achieve the statutory

goals ot part D NSR and the maintenance provisions of section

175A.

B. Part D NSR and contingency Provisions

Requiring the full appr~val of a part 0 NSR program would

ensure that the program would. become a contingency provision in

the maintenance plan. As stated above, pursuant to section

175A(d) and section 107(d) (3)(E), the contingency plan must

contain, at a minimum, all measures contained in th."

nonattainment SIP." However; EPA is interpreting the term

"measure" as used in se'ction 175A(d) ,so as not to inolude part D

NSR,'

The term "measure- is, not defined in section 17SA(d) and'

Congress utilized that term differently, in different provisions

of the Act with'respect to the PSO and part.D NSR permitting. programs. For example, in section 110 (a) (2) (A), Congress

required that SIP's include "enforceable emission limitations and

other control measures, means, o~ techniques • " '., as may be

necessary or appropriate to meet the applicable requirements of

the Act." In section 110(a)(2)(C), Congress required that SIP's

include "a program to provide for the enforcement of the measures

described in subparagraph (A), ADS regulation of the modification

and construction of any stationary source within the areas

covered by the plan as necessary to assure that national ambient

air quality standards are achieved, inclUding a permit program as

required in parts C and 0 (i.e., PSO and part 0 NSR) ." (Emphasis

added. )

If the term lImeasures,ll as used in sections 110(a) (2) (A) and

110(a) (2) (C), had been intended to include PSO and part 0 NSR,

there would have been no point to requiring that SIP's include

both measures and preconstruction review under parts C and 0 (PSD

or part 0 NSR). Thus, in sections 110(a)(2)(A) and (C), it is

apparent that Congress distinguished the requirement for

IImeasures" from the requirement for preconstruction review

programs. On the other hand, in other provisions of the Act,

such as section 161, Congress appears to have included pSD within__ the scope of the term "measures. 1I

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The fact that Congress used the undefined term "me.sure"

differently in different provisions of the Act indicate. that the

term is susceptible to more than one interpretation and that EPA

has the discretion to interpret it in a reasonable manner in the

context of section 175A. Inasmuch as Congress itself h•• used

the term in a manner that excluded PSD and part D NSR from its

scope, EPA believes it is reasonable to interpret "meaaure,· ~s

used in section 17SA (d) ,. not to inclUde part 0 NSR. The.· .... f "reasonableness of this interpretation is further supported by the , fact that PSD, a program that is the corollary of part D NSR for

attainment areas, goes into effect in lieu of part D NSR,4 and

that, as discussed above, EPA intends to implement the PSD and

other NSR programs in a way that will achieve the basie atatutory

goals of part 0 NSR. Therefore, EPA does not believe that part 0

NSR need be part of an area's contingency plan.

IV. other Required Programs··

The EPA is not changing its previously stated p~licy with

respect to the need for states to adopt and receive fUll approval

of other programs required by the Act prior. to or at the time of

the submission of a redesignation request. The existence of a

corollary program for attainment areas distinguishes part 0 NSR

from other required programs under the Act, such as enhanced

inspection and maintenance and reasonably available centrol

technology (RACT) programs, which have no corollary program.

Moreover, EPA believes that those other required programs are

clearly within the scope of the term "measure" as used 1n section

175A.

For further information regarding part 0 NSR requireroents

for areas redesignating to attainment, please contact Carla

Oldham at (919) 541-3347; for general information about PSo

requirements for attainment areas, contact Dennis crumpler at

(919) 541-0871.

cc: . Air Branch Chief, Regions I-X

~EPA is not suggesting that NSR and PSD are equivalpnt, but

merely that they are the same type of program. ~I 6: 4
MEMORANDUM

UN"~lJ STAll::S ENVIRONMENTAL PIiOILUI()1\! A(;I r'J( 't

Oflice of All Ouallty Planl1lf1!-l ,IIHI Sldlh~,11 d'.

Fh~~l~dlcll lrlitl1!-llt~ Park, Nurllll:.".oIl1l.t :' i"; :

NOV 301993

SUBJECT:

FROM:

TO:

Use of Actual Emissions in Maintenance Demonstrations

for Ozone and Carbon Monoxide (CO) Nonat;ainme~ Areas

D. Kent Berry, Acting Director (MD-1 j)~~j-f-5':~r Air Quality Kanaqement Division £;' tI

Director, Air, Pesticides and Toxics

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III . Director, Air and Radiation Division,

Region V ~irector, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics. Division,

Regions VII, VIII, IX, and X

This memorandum provides guidance on the use of actual

emissions in maintenance demonstrations for ozone and CO

nonattainment areas seeking redesignation to attainment. This

guidance supersedes previous Environmental Protection Agency

(EPA) guidance set forth in the September 4, 1992 memorandum from

John calcagni to Air Division Directors, "Procedures for

Processing Requests to Redesignate Areas to Attainment"

(redesignation policy), which required emission projections for

these areas to be based on allowable emissions.

The EPA has previously issued guidance on the use of actual

emissions in projecting emissions to meet the requirements for

the 15 percent rate-of-progress plans for ozone nonattainment

areas. 1 For consistency, this memorandum extends the policy of

using actual emissions to maintenance projections for ozone and

CO areas, as well. This guidance is not intended to apply to

emission projections in control programs for the other criteria

pollutants (see discussion under"Other pollutants").

lSee Guidance for Growth Factors, Projections, and Control

Strategies for the 15 Percent Rate-of Progress Plans (EPA-452/R93-002, March 1993).

7-14
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2

Ozone and CO Policy

Actual emissions from a source are the emissions based on

the source's actual operating hours, production rates, and

control equipment for the processes carried out at the source.

Actual emissions take into consideration normal operating

conditions as well as instances when deviations occur. For ozone

and CO areas, the term allowable emissions refers to emissions

estimates based on enforceable emission rates and actual

production rates and hours.

Consistent with the earlier rate-of-progress plan guiaance,

ozone and CO maintenance projections may be based on actual

emissions for sources or source categories that are currently

sUbject to a regulation and that the state does not anticipate

sUbjecting to additional regulation. Similarly, the maintenance

projections may be based on actual emissions for sources or

source categories that are currently unregulated and are not

expected to be sUbject to future regulation. (The State still

has the option of using allowable emissions for these"' two cases.)

However, for sources that are expected to be sUbject to

additional regulation, the projections. must be based on the new

allowable emissions limits because the new actual emissions are

not yet known.

Upon approval of aredesignation request and associated

maintenance plan by EPA, all futurep-lUissions calculations or

projections to implement other air quality requirements for an

area must be consistent with the maintenance demonstration

(unless a more stringent requirement applies). For example, if

projected emissions from a source used in the maintenance

demonstration are based on actual emissions, that source must use

actual emissions in determining the credit available for

emissions trading, innovative strategies, economic incentive

plans, and emissions bUdgets.

Other Pollutants

Under the redesignation policy, emissions projections for

particulate matter (PM-10), sulfur dioxide (S02) , nitrogen

dioxide, and lead (Pb) nonattainment areas are still required to

follow current EPA modeling guidance. 2 The modeling guidance

requires that maximum allowable emission limits for major point

sources be used in demonstrating maintenance of short-term

2Irhe EPA-approved modeling guidance may be found in the

following documents: "Guideline on Air Quality Models (Revised)lI

(EPA-450/2-78-027R, July 1987) and "PM-10 SIP Development

Guideline" (EPA-450/2-86-001, June 1987).

7-15
3

standards.] It is necessary to continue the use of maximum

allowable emissions when projecting emissions for these

nonattainment areas because, in some cases, large point sources

operating at full capacity could by themselves cause an

exceedance of the applicable national ambient air quality

standard. In contrast, large point sources are not likely to be

dominant emission sources in inventories for ozone and CO

nonattainment areas, and it is unlikely that the multitude of

smaller sources would be operating at maximum capacity

simultaneously.

For further information regarding the use of actual aAd

allowable emissions for maintenance demonstrations for ozone and

CO areas, please contact Carla Oldham at (919) 541-3347. For

information on projecting emissions for S02, PM-10, and Pb

nonattainment areas, please contact Robin Dunkins at (919) 541-

5335.

cc: Air Branch Chief, Regions I-X

John Cabaniss, OMS

Mary Henigin, OAQPS

Bob Kellam, TSD

Rich Ossias, OGC

John Rasnic, SSCD

John Seitz, OAQPS

Ann Goode, OAR

Lydia Wegman, OAQPS

]Maxicurn allowable emissions are calculated using the

enforceable (i.e., allowable) emission rate mUltiplied by the

maximum operating capacity of that source at continuous operation

(unless there are federally-enforceable limits on the hours of

operation).

7-16
MEMORANDUM

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

SEP I 7 1993 OFFICE OF

AIR AND RADIATION

SUBJECT:

FROM:

TO:

I.

State Implementation Plan (SIP) Requirements for Areas

Submitting Requests for Redesignation to Attainment of

the Ozone and Carbon MonOXide~(co) National Ambient Air

Quality Standards (N QS) on 0 a eF November 15, 1992 . Michael H. Shapiro . Acting Assistant A ministra 0

for Air and Radiation (ANR~443)

Director, Air, Pesticides and Toxics

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II . Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics Division,

Regions VII, VIII, IX, and X

Purpose

The purpose of this memorandum is to address State requests

to redesignate from nonattainment to attainment of the ozone and

CO NAAQS under section 107. Specifically at issue are requests

submitted on or after November 15, 1992 where outstanding Clean

Air Act (Act) requirements have not been met. This memo provides

guidance on the statutorily-mandated control programs that must

be in the EPA-approved SIP if EPA is to approve the redesignation

request. The Act's requirements for redesignation and a list of

EPA's redesignation pOlicy and guidance are included in

Attachments A and B. In the future, further guidance may be

provided for redesignations submitted after November 15, 1993.

ro Recycled/Recyclable n- n Printed with Soy/canola Ink on paper that

'0<;7 contains at least 50% recyded fiber
2

II. Policy Summary

section 107(d) (3) (E) (v) of the Act as amended (amended Act)

provides that the state must have met all applicable requirements

of section 110 and part D in order to be redesignated.

Furthermore, section 107(d) (3) (E) (ii) provides that the State

must have a fully-approved SIP for the area seeking

redesignation.

The EPA is interpreting these section 107 provisions to

require satisfactory completion of the current Act planning

requirements. Specifically, before EPA can act favorably upon

any State redesignation request, the statutorily-mandated control

programs of section 110 and part D (that were due prior to the

time of the redesignation request) must have been adopted by the

State and approved by EPA into the SIP.

Thus, with respect to redesignation requests submitted on or

after the Act's deadline for submittal of the required programs,

States must generally adopt and provide for implementation of

their regulations for all of the programs that were due. States

must submit these plans to EPA for incorporation into the SIP. l

This would include such requirements as emissions inventories

andlor emission statements. Such requirements must be met in

order for the area to have a fully-approved' SIP that meets all

requirements applicable to the area under section 110 and part D.

The amended Act, however, also provides that upon

redesignation, a State may move measures from the implemented SIP

to the contingency plan portion of the SIP if the State

demonstrates that such measures are not needed for maintaining

the NAAQS. Many areas sought redesignation at or about the same

time they were required to adopt and implement the requirements

due on November 15, 1992. In many instances, the State will be

able to immediately move these measures to the contingency plan

without implementation.

III. Exceptions to Policy

The EPA decided to review the requirements to determine if

something less than full adoption of these regulations would be

acceptable under the Act for areas seeking redesignation.

Exceptions to this policy on the States' need to complete the

full planning and adoption process for the November 15, 1992

mandated programs are very limited. The language in the Act

allows a degree of flexibility in only four program areas. These

are: (1) basic inspection and maintenance (11M), (2) annual

updates of vehicle miles traveled (VMT) forecasts and annual

lNote that this represents a departure from earlier guidance

for part D new source review (NSR) regulations.
3

estimates of actual VMT for CO nonattainment areas, (3) nitrogen

oxides (NOx) reasonably available control technology (RACT), and

(4) small business programs (SBP).

These exceptions are only applicable in areas for which EPA

approves a redesignation. The states should be aware that if EPA

denies a redesignation request, rules submitted in accordance

with this guidance may also be disapprovable. Finally, because

EPA anticipates issuing onboard regulations by January 1994,

states seeking redesignation of areas classified as moderate may

have some flexibility with respect to the stage II requirement.

Our guidance for state submittals covering these four

programs is described in the following paragraphs.

Basic 11M

For areas where maintenance plans do not rely on

implementation of a basic 11M program immediately following

redesignation, the 11M component of the SIP should include:

1. Legislative authority for basic 11M such that

implementing regulations can be adopted without any further

legislative action.

2. A provision in the SIP providing that basic 11M be

placed in the contingency measures portion of the maintenance

plan upon redesignation.

3. An enforceable schedule and commitment by the Governor

or his designee for adoption and implementation of a basic 11M

program upon a specified, appropriate triggering event.

Note that, for purposes of consideration of a redesignation

request submitted after November 15, 1992, the commitment as

described in the 11M regulation (see 57 FR 52950, November 5,

1992) is not sufficient to meet the Act's requirement for a

fUlly-approved SIP.

In addition, please note that, EPA's final 11M regulations

in 40 CFR part 51 require a fully-adopted 11M program by

November 15, 1993. At this time, our preliminary interpretative

guidance on basic 11M in this memo is not discussed in the 11M

regulations. Therefore, EPA is proceeding to establish this

interpretation through regulatory action, thus enabling EPA to

accept legislative authority and a commitment to adopt and

implement basic 11M regulations for those areas being

redesignated to attainment.
4

VMT Forecasting

The VMT forecasting SIP for CO should include:

1. Annual forecasts of VMT (i.e., average daily VMT for the

peak 3-month CO seasons for 1993, 1994, and 1995 in moderate

areas above 12.7 ppm, and until 2000 in serious areas).

2. An enforceable commitment by the Governor or his

designee to estimate actual annual VMT for each of these years

(by September 30 of the following year) and to update the

forecast of the VMT in the remaining years.

3. A request that the commitment be moved to the

contingency plan portion of the SIP upon redesignation, becoming

a contingency provision triggered by a specified triggering

event.

4. Adopted contingency measures to reduce CO emissions.

The implementation of such measures is contingent upon either:

(a) an annual estimate of actual VMT or updated forecast of VMT

exceeding the previous forecast for that year, or (b) the area

failing to attain by the CO attainment deadline. These

contingency measures must meet the requirements of section

187(a) (3) as interpreted by the April 16, 1992, "General Preamble

for the Implementation of Title I of the Clean Air Act Amendments

of 1990," including the requirement that no further action by the

State is needed for them to take effect.

NOx RACT

section 182(f) provides that States may request an exemption

from the NOx RACT requirements. The NOx RACT requirements of

section 182(f) do not apply if additional reductions of NOx would

not contribute to attainment. 2 In an area that did not implement

the section 182(f) NOx requirement but did meet the ozone

standard, as demonstrated by adequate monitoring data consistent

with EPA guidance, it is clear that the additional NOx reductions

required by section 182(f) would not contribute to attainment,

although they might contribute to maintenance. Therefore, EPA

believes that if a State submits a redesignation request along

with a section 182(f) exemption request based on monitoring data

demonstrating attainment of the ozone NAAQS, further

documentation is not required. The State may follow one of two

approaches in making such a submittal:

2Note that the section 182(f) exemption for NOx RACT and NSR

requirements described in this section is applicable only for

States outside an ozone transport region, since only those States

fall under the section 182(f) "contribute to attainment"

provision.
5

1. Submit a redesignation request along with a section

182(f) exemption request based solely upon monitoring data

showing that the area's air quality is meeting the ozone NAAQS;

and submit a maintenance plan SIP revision, which includes a NOx

RACT program as a contingency measure. In lieu of adopted NOx

RACT rules, such a NOx RACT program may consist of an enforceable

schedule and commi~ment by the Governor or his designee to adopt

and implement the NOx RACT rules upon a specified, appropriate

triggering event.

2. An exemption request based on both ambient monitoring

and urban airshed modeling consistent with EPA guidance that

shows additional NOx reductions would not contribute to

attainment in the area. In this case, NOx RACT rules do not have

to be included as a contingency measure of the maintenance plan.

For several reasons, the Act can be interpreted as not

requiring the section 507 SBP submittal in order for EPA to

approve a redesignation request. The SBP submittal is required

regardless of whether there are any designated nonattainment

areas within the State. In addition, the SBP is not a control

measure intended to contribute to the emission reductions

achieved by an area; rather it is a service provided to help

small businesses comply with requirements of the Act. For the

above reasons, EPA is interpreting the SBP as not being an

applicable requirement for any specific nonattainment area that

is seeking redesignation. However, EPA will continue to ensure

that States make SBP submittals in a timely fashion.

Stage II Vapor Recovery

stage II vapor recovery remains an applicable requirement

for moderate ozone nonattainment areas until EPA promulgates

onboard vapor recovery regulations. section 202(a) (6) of the Act

provides that once onboard regulations are promulgated, the Stage

II regulations required under section 182(b) (3) are no longer

applicable for moderate ozone nonattainment areas. Therefore,

final redesignation for a moderate nonattainment area that occurs

after EPA's onboard regulations are promulgated does not have to

include a Stage II SIP control program. For redesignation

requests that are submitted before EPA promulgates onboard rules

and that do not include Stage II rules for moderate areas,

Regional Offices may prepare rulemaking actions proposing to

approve the redesignation, if appropriate, as long as final

approval occurs after EPA promulgates onboard regulations.
6

IV. Coordination of SIP Submittals and Redesignation

Reguests

If the State elects to follow the approach above, the State

should submit the SIP control program as described above along

with the redesignation request and maintenance plan. The EPA

will review the required SIP sUbmittal(s) against EPA policy and

guidance and in coordination with the redesignation request and

maintenance plan. Approvability of the redesignation is directly

related to the approvability of the SIP submittals (i.e., EPA is

precluded from approving a redesignation to attainment if the SIP

is not approvable).

As a general policy, a State may not relax the adopted and

implemented SIP for an area upon the area's redesignation to

attainment. States should continue to implement existing control

strategies in order to maintain the standard. However, section

175A recognizes that States may be able to move SIP measures to

the contingency plan upon redesignation if the State can

adequately demonstrate that such action will not interfere with

maintenance of the standard. The type of demonstration necessary

is dependent upon the pollutant for which the area has been

redesignated to attainment.

In order to make such a demonstration for an area

redesignated to attainment for CO, EPA believes that the State

could submit a revised control strategy demonstration showing

that the measure is not necessary to maintain the standard. For

ozone, the State would need to submit an attainment modeling

demonstration consistent with EPA's current "Guideline on Air

Quality Models," showing that the control measure is not needed

to maintain the standard. The EPA intends to be very cautious in

approving such revisions in cases where the control measures were

implemented during the time the area attained the standard; the

State's demonstration should indicate an ample margin of safety

with respect to maintenance of the standard.

V. Conclusion

In summary, full adoption of all of the statutorily-required

programs, as well as a schedule and an enforceable commitment for

an implementation date, are necessary for redesignation to

attainment from nonattainment for ozone or CO if the

redesignation request is submitted after the statutory due date

for the program. The few exceptions to this requirement are

basic 11M, annual updates of VMT forecasts, and estimates of

actual VMT, NOx RACT, and SBP.

If you have any questions, please contact Sharon Reinders at

(919) 541-5284, or Annie Nikbakht at (919) 541-5246.
Attachment A

criteria For Redesignation Under Section 107(d)

section 107{d) (3) (E) of the Act states five criteria that

must be met before the Administrator may redesignate an area to

attainment. The criteria are:

1. The EPA has determined that the NAAQS have been

attained.

2. The applicable implementation plan has been fully

approved by EPA under section 110{k).

3. The EPA has determined that the improvement in air

quality is due to permanent and enforceable reductions in

emissions.

4. The State has met all applicable requirements for the

area under section 110 and part D.

5. The EPA has fUlly approved a maintenance plan, including

a contingency plan, for the area under section 175A.
Attachment B

The EPA policies for implementing section 107 of the Act for

redesignations are contained in the following memorandums.

1. "Procedures for Processing Requests to Redesignate Areas

to Attainment," John Calcagni, Director, Air Quality Management

Division, september 4, 1992.

2. "state Implementation Plan (SIP) Actions Submitted in

Response to Clean Air Act (CAA) Deadlines," John calcagni,

Director, Air Quality Management Division, October 28, 1992.

3. "contingency Measures for Ozone and Carbon Monoxide (CO)

Redesignations," G. T. Helms, Chief, Ozone/Carbon Monoxide

Programs Branch, June 1, 1992.

4. "Maintenance Plans for Redesignation of Ozone and Carbon

Monoxide Nonattainment Areas," G. T. Helms, Chief, ozone/Carbon

Monoxide Programs Branch, April 30, 1992.

In the event that EPA does not approve the redesignation,

the applicable I/M program requirements and guidance can be found

in 57 FR 52950, November 5, 1992 and in 40 CFR part 51. The

applicable VMT forecast guidance is described in the document

entitled, "Section 187 VMT Forecasting and Tracking Guidance,"

January 1992.
./

UNITED STATES ENVIRONMENTAL P~OTECTION AGENCY

Office of Air Quality Plannlng and Standards

Research Triangle Park, North Carolina 27711

1'1 AUG 1993

MEMORANDUM

SUBJECT: Technical support Documents (TSD's) for

Redesignation Ozone and Carbon Monoxide (CO)

Nonattainment Areas

.' /~-~. FROM: G. T. Helms, Chief //0)

Ozone/Carbon Monoxide Programs Branch (MD-15)

TO: Air Branch Chief, Regions I-X

The purpose of· this memorandum is to request your help in

trying to upgrade the TSD's prepared by the Regional Offices

which support Federal Register notices of proposed and final

rulemaking actions on ozone and CO redesignations.

To make the review process flow more efficientl

reduce Headquarters review time and move State' ement ion

plan (SIP) actions from Table 1 to Table 2, 1t is important for

Headquarters to quickly process redesignation packages. To do

this, we will rely heavily on the Regional Offices to review the

State submittals and present the results of their reviews in the

TSD. 1 Therefore, it is important that the Regional Offices

present documentation in the TSD to support the Environmental

Protection Agency's (EPA's) evaluation of the submittals along

with the complete technical basis for EPA's rulemaking action.

For redesignations, the TSD should answer basic questions

such as:

- What years are the supporting air quality data covering?

Where are the monitors located? What are the relevant

concentrations?

- For what years were emissions inventories prepared and how

were they developed? In the interim, what are the total

lNote that a TSD should be prepared for the proposed rUlemaking

action or a direct final action. If EPA's position changes prior

to final rUlemaking, the reasons for the changes are normally

addressed in the notice of final rulemaking rather than redrafting

the TSD. General information on TSD's is in the document entitled,

"Processing Procedures For SIP Revisions For Part 52, Part 62

111(d) Plans, and Part 81 Redesignations."
• J

2

season-day and/or annual emissions by pollutant for point,

area, and mobile sources for the attainment and maintenance

years?

- What transportation, emission, and/or dispersion models

were used? What were the significant input parameters;

including air quality data and assumptions used in the

demonstration? What are the model results?

- What are the maintenance plan triggers, commitments, and

contingency measures? What is the process for tracking the

plan and reportiqg results to EPA? What are the adoption

and implementation schedules for the contingency measures?

How is maintenance demonstrated in the interim years? Are

additional controls to be adopted and implemented in the

future to offset emission increases, and what is the impact

of these controls on emissions inventory planning cap(s)?

- When was the public hearing and what are the results of

any comments received by the state? What is the status of

an outstanding SIP call or findings letter, if any?

-What is EPA's evaluation of the State's supporting

materials that accompanied the sUbmittal, such as the

technical data and commitment letters, and how do these

materials conform to EPA policy, guidance, and the Clean Air

Act?

Hopefully, you are checking the emissions inventories

submitted for redesignations and they are of the same quality as

those submitted to meet nonattainment area requirements. If this

is not the case, you should start transitioning to better

inventories. You may use the relevant portions of the document

entitled, "Quality Review Guidelines For Base Year 1990 Emission

Inventories," as a guide to summarizing the inventories in the

TSD.

If you have any questions, please contact Sharon Reinders at

(919) 541-5284.
• UNITED S~AT,ES ~NVIRONMENTAL PROTECTION AGENCY

Office (ri,A!r Quality Planning and Standards

Research Triangle Park. North CarOlina 27711

OCT 281992

MEMORANDUM

.'

SUBJECT:

FROM:

TO:

State Implementation Plan (SIP)_Actions Submitted in

Response to Clean Air Act ~ct) D~ines .." .~. ".~.:.

John Calcagni, Director ~. I..Z ;.~~

Air Quality Management D~~ision, OAQPS\{MO-15)

, .'

Director, Air, Pestici~s and Tdxics:

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation, and Toxics Division,

Region III

Director, Air aryd Radiation Division,

Region V

Director, Air, Pesticides, and Toxics Division,

Region VI ' ':

Director, Air and Taxies Division,

.Regions VII, VIII, IX, and X

•

The purpose of this memorandum is to cla~ify issues related

to redesignation requests and SIP actions submitted in response

to Act deadlines, and specifically address SIP elements that are

due November 15, 1992. The following topics are addressed below:

completeness determinations on commitment submittals; requests

for parallel processing to meet Act deadlines; effect of

redesignation requests on mandatory Act SUbmittals; completeness

determinations on emission inventory SUbmittals; and issuing

letters to the States making a finding of failure to submit a

required SIP, or SIP element.

Completeness Determinations on Commitment Submittals

In anticipation of commitment SIP's being SUbmitted to the

Environmental Protection Agency (EPA) as authorized by section

110(k)(4) of the Act, my staff are working with the Office of

General Counsel (OGe) to revise the completeness criteria in

Appendix V of 40 CFR Part 51.~ Specifically, it is our intent to

include specific completeness criteria for committal SIP's.

A July 22, 1992 memorandum from Michael Shapiro identified a

number of statutory requirements for which EPA is inclined to

accept committal SIP's. (A clarification of that memorandum was

issued by Michael Shapiro on September 16, 1992.)

61 21, -/- r' I,., .)
•

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•

2

The current completeness criteria do not address commitments

submitted under section 110(k)(4) of the Act. However, we are

interpreting section 110(k)(4) as allowing EPA to accept commitments from a State as complete submittals even though commitments

will .~ack some of the substantive elements required under the

current completeness criteria. Consequently, committal SIP's

submitted to EPA should be reviewed against only those e~ements

of the completeness criteria that are directly applicable to

commitments in order to be determined complete. The elements of

the completeness cri~eria that are.applicable to commitments are:

1. A formal letter of submittal from the Governor or his

designee requesting EPA approval of the commitment.

2. The commitment was SUbject to a pUblic hearing pursuant

to 40 eFR 51.102.

3. The submittal contains a schedule for the adoption of

the statutorily required measures.

Additionally, States should be encouraged to submit documentation

and a justification explaining the need for a commitment ..

If a Regional Office receives a submittal that contains one

or more commitments in association 'with other rules or control

measures, the Region should consult with the responsible

Headquarters program office to determine if a commitment is

acceptable in that specific circumstance. (Please refer to my

July 9, 1992 memorandum entitled "Processing of State

Implementation Plan SUbmittals," specifically the part on

conditional approvals.) If EPA determines that it will consider

the commitment under the conditional approval process, the

commitment should be reviewed only as to the criteria that would

be applicable for commitments. However, if EPA determines that a

commitment cannot be used to meet the statutory requirement, the

submittal should be reviewed against all elements of the

completeness criteria.

Requests for Parallel Processing to Meet Act peadlines

The EPA expects a number of States to request parallel

processing of draft rules as a way to meet Act deadlines. A

State request for parallel processing is not an official

submittal satisfying a statutory deadline since it is a draft

rule (i.e., the State has yet to adopt the regulation).

When the completeness criteria were promulgated with an

exception for parallel processing, EPA was not anticipating

submittals SUbject to statutory deadlines. The intent was to

continue the timesaving concept of parallel processi~g Stateinitiated actions. However, the exceptions in the completeness

criteria could be interpreted ~s ~equiring EPA to accept draft

2076
•

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3

rules in order to meet statutory deadlines. As noted above,

draft submittals are not considered plan submittals under the Act

because they have not been adopted by the State. Consequently,

EPA is not precluded from making a finding of failure to submit a

required SIP element when a State submits a draft rule.

If a request for parallel processing is sUbmitted. to EPA

before the statutory deadline, EPA may agree to parallel process

the action. However, EPA will not make a completeness finding

under section 110(k)(1) since that section applies to official

plan submittals and hot draft rules. However, it the statutory

deadline passes and a State has not submitted the fully-adopted

regulation, the Regions should make a finding of failure to

submit under section 179(a)(1). This will initiate the sanctions

time clock.

Subsequently, if a State submits a fUlly-adopted rule or

maintenance plan, EPA will review the submittal aqainst the

completeness criteria. The EPA will commence rulemaking action

if the submittal is complete. If the completene•• criteria are

met, a finding of completeness will stop the time clock for . sanctions~ If the completeness criteria are not met, EPA should

make a finding of incompleteness, thereby maintaining the

previous time clock for sanctions.

Because the parallel processing exception could be

interpreted to require EPA to accept draft rules as meeting a

statutory deadline, we are presently revising the completeness

criteria to remove the parallel processing exception. It should

be noted, however, that although parallel processing submittals

are not official plan SUbmittals, EPA will continue to use

parallel processing as an effective avenue for approving State

rules expeditiously.

Effect of Redesignation Requests on Mandatory Act Submittals

It has come to our attention that some States plan to submit

redesignation requests prior to November 15, 1992 with the

understanding that this will exempt them from implementing

mandatory Act programs due to start in November (e.g., oxygenated

fuels program, stage II vapor recovery rules, etc.). The

approvability of a redesignation request is ba7ed on the

requirements applicable as of the date of submlttal of.a complete

redesignation request. 2 States, however, are statutorlly

2 For a redesignation request to be complete, any portions of the

redesignation request that are SIP revisions (e.g.,

maintenance_plans and any additional control measures) must meet

the completeness criteria for SIP revisions. Redesignation request~ submitted for parallel proces7ing will not" be considered

official submittals; therefore, they wl11 not be treated as

complete submittals. 20 ! !
2D/e)

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4

obligated to meet SIP requirements that become due any time

before an area is actually redesignated to attainment. Such

redesignation occurs when EPA has taken final rulemaking action

to approve 8 redesignation request.

-.".

Hence, if there is a failure by the State to meet a

statutory deadline' for an area (before EPA has redesiqnated the

area as attainment), a finding of failure to submit should be

made. This, in turn, begins the sanctions process under section

179(a) (see September 4, 1992 memorandum, entitled "Procedures

for Processing Requests to Redesignate Areas to Attainment").

The findings letter should recognize any pending redesiqnation

request, note the State's statutory obligation to implement any

mandatory requirements that are due, and indicate that one of the sanct~ons ~ill be imposed after 18 months unless EPA approves the

redes1gnat10n request before the 18-month period has ended.

Thus, .the Regions S~9~ld ~p. ":e all reasonable attempts to ensure

that the redesignation approval process does not take over 18

months.

completeness Determinations on Emission Inventory Submittals

In a September 29, 1992 memorandum from William Laxton and

myself addressing pUblic hearing requirements for emission

inventory submittals, it was stated that EPA was providing a "de

minimis" deferral of the pUblic hearing requirement tor emission

inventory submittals. In that memorandum, it-was also stated

that if emission inventory submittals do not meet the

completeness criteria (except for the deferred public hearing

requirement), EPA should make a finding of incompleteness.

However, that memorandum did not specify the process for making

completeness determinations on emission inventory sUbmittals that

only lack the pUblic hearing element.

After discussion with OGe, we have determined that for the

·emission inventory submittals that are only lacking evidence of a

public hearing, EPA should make a finding of completeness

contingent upon the state fulfilling the pUblic hearing

requirement. The completeness letter to the state should

indicate that the completeness determination is contingent upon

the state's fulfilling the pUblic hearing requirement by the time

identified in the September 29 memorandum. If the pUblic hearing

requirement is not met by the time specified, then EPA will make

a finding of incompleteness on the original emission inventory . submittal. The completeness letter should further state that the

public hearing requirement must be met before or at the time of

submittal of a rate-of-progress or maintenance plan, or at the

time the inventory takes on regulatory significance Such as

providing a basis for banking or trading.
•

•

•

-

5

As noted in the September 29 memorandum, EPA also is

providing a "de minimis" deferral of the requirement for EPA to

take action on the emission inventory submittals. The 12-month

statutory timeframe for approving or disapproving the emission inven~ory submittal will start at the time the public hearing

requirement is met. If EPA has found the submittal incomplete,

EPA will not be required to take approval action on the . submittal.

Issuing Letters to the States Making a Finding Qf Failure tQ

Submit a Required SlY Qr SIP Element

The Regional Offices should be planning tQ issue fin~ings Qf

failure to submit to States nQt meeting the NQvember 1992 (and

other) statutory deadlines. The Agency has taken a strong stance

that such findings shQuld be made soon after a due date has

passed. Notice that a State has failed tQ sUbmit. SIP, or SIP

element, is made in the form of a letter from the Regional

Administrator.to the GQvernQr of a State. Please refer ~o the

July 22, 1992 Shapiro memorandum, entitled "Guidelines for State

Implementation Plan (SIP) Submittals Due November 15, 1992," for

further information. Further guidance will be made available on

the schedule and format of the findings •

If you have any questions on this memorandum, please contact

Denise Gerth at (919) 541-5550.

cc: Chief, Air Programs Branch, Regions I-X

JQhn Cabaniss

Jeff Clark

Denise Devoe

TQm Helms

Steve Hitte

Steve·HQQver

Ed Lillis

David MQbley

Rich ossias

JQe Paisie

Lydia Wegman

2013
!

'., ,. '", .'

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

Office of Air Quality Plannmg and Standards

Research Triangle Park, North Carolina 27711

4SEP 1992

MEMORANDUM

SUBJECT: Proce~ures for Processing

to Attainment

Director, Air, Pestic' es and Toxics nt

Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III '

Director, Air and Radiati6n Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics Division,

Regions VII, VIII, IX, and X

FROM: ~6hn Calc~ni, Directo~~~~

Air Quality Management

TO:,

Purpos@

The Office of Air Quality Planning and Standards (OAQP5)

expects that a number pf redesignation requests will be submitted

in the near future. Thus, Regions will need to have guidance on

the applicable procedures for handling these requests, including

maintenance plan provisions. This memorandum, therefore,

consolidates the Environmental Protection Agency's (EPA's)

guidance regarding the processing of requests for redesignation

of nonattainment areas to attainment for ozone (03)' ca~bon

monoxide (CO), particulate matter (PM-10), sulfur dioxide (502)'

nitrogen dioxide (N02 ), and lead (Pb). Regions should use th1s

guidance as a general framework for drafting Federal Register

notices pertaining to redesignation requests. 5pe~ial concerns

for areas seeking redesignation from unclassifiable to attainment

will be addressed on a case-by-case basis.

Background

Section l07(d)(3)(E) of the Clean Air Act, as amended,

states that an area can be redesignated to attainment if the

following conditions are met:
2

1. The EPA has determined that the national ambient air

quality standards (NAAQS) have been attained.

2. The applicable implementation plan has been fUlly

approved by EPA under section 110(k).

3. The EPA has,determined that the improvement in air

quality is due to permanent and enforceable reductions in

emissions.

4. The state has met all applicable requirements for the

area under section 110 and Part D.

5. The EPA has fully approved a maintenance plan, including

a contingency plan, for the area under section 175A.

Each of these criteria is discussed in more detail in the

following paragraphs. Particular attention is given to

maintenance plan provisions at the end.of this document since

maintenance plans constitute a new requirement under the amended

Clean Air Act. Exceptions to the guidance will be considered on

a case-by-case basis.

1. Attainment of the standard

The state must show that the area is· attaining the

applicable NAAQS. There are two components involved in making

this demonstration which should be considered interdependently.

The first component relies upon ambient air quality data. The

data that are used to demonstrate attainment should be the

product of ambient monitoring that is representative of the area

of highest concentration. These monitors should remain at the

same location for the duration of the monitoring period required

for demonstrating attainment. The data should be collected and

quality-assured in accordance with 40 CFR 58 and recorded in the

Aerometric Information Retrieval System (AIRS) in order for it to

be available to the pUblic for review. For purposes of

redesignation, the Regional Office should verify that the

integrity of the air quality monitoring network has been

-preserved.

For PM-10, an area may be considered attaining the NAAQS if

the number of expected exceedances per year, according to 40 CPR

50.6, is less than or equal to 1.0. For 0 3 , the atea must show

that the average annual number of expected exceedances, according

to 40 CFR 50.9, is less than or equal to 1.0 based on data from

all monitoring sites in the area or its affected downwind

environs. In making. this showing, both PM-IO ~nd 0 3 must r 7ly on

3 complete, consecut1ve calendar years of qual1ty-assured a1r

quality monitoring data, collected in accordance with 40 CFR 50,

Appendices Hand K. For CO, an area may be considered attaining

the NAAQS if there are no violations, as determined in accordance
3

with 40 CFR 50.8, based on 2 complete, conSecutive calendar years

of quality-assured monitoring data. For S02' according to 40 CFR

50.4, an area must show no more than one exceedance annually and

for Pb, according to section 50.12, an area may show no

exceedances on a quarterly basis.

The second component relies upon supplemental EPA-approved

air quality modeling. No such supplemental modeling is required

for 0 3 nonattainment areas seeking redesignation. Modeling may

be necessary to det~rmine the representativeness of the monitored

data. For pollutants such as S02 and CO, a small number of

monitors typically is not representative of areawide air quality

or areas .of highest toncentration. When dealing with S02' Pb,

PM-10 (except. for a limited number of initial moderate

nonattainment areas), and CO (except moderate areas with. design

values of 12.7 parts per million or lower at the time of passage

of the Clean Air Act Amendments of 1990), dispersion modeling

will generally be necessary to evaluate comprehensively sources'·

impacts and to determine the areas of expected high

concentrations based upon current conditions. Areas which were

designated nonattainment based on modeling will generally not be

redesignated to attainment unless an acceptable modeling analysis

indicates attainment. Regions should consult with OAQPS for

further guidance addressing the need for modeling in specific

circumstances.

2. state Implementation Plan (SIP) Approval

Thr SIP for the area must be fully approved under section

110(k),and must satisfy all requirements that apply to the

area. It should be noted that approval action on SIP elements

and the redesignation request may occur simultaneously. An area

cannot be redesignated if a required element of its plan is the"

SUbject of a disapproval; a finding of failure to submit or to

implement the SIP; or partial, conditional, or limited approval.

However, this does not mean that earlier issues with regard to

the SIP will be reopened. Regions should not reconsider those

things that have already been approved and for which the Clean

Air Act Amendments did not alter what is required. In contrast,

to the extent the Amendments add a requirement or alter "an

existing requirement so that it adds something more, Regions

should consider those issues. In addition, requests from areas

known to be affected by dispersion techniques which are

inconsistent with EPA guidance will continue to be/considered

unapprovable under section 110 and will not qualify for

redesignation.

1Section 110(k) contains the requirements for EPA action on

plan submissions. It addresses completeness, deadlines, full and

partial approval, conditional approval, and disapproval.
4

3. Permanent and Enforceable Improvement 'in Air Quality

The state must be able to reasonably attribute the

improvement in air quality to emission reductions which are

permanent and enforceable. 2 Attainment resulting from temporary

reductions in emission rates (e.g., reduced production or

shutdown due to temporary adverse economic conditions) or

unusually favorable meteorology would not qualify as an air

quality improvement due to permanent and enforceable emission

reductions. .

In making this showing, the state should estimate the

percent reduction (rrom the year that was used to determine the

design value for designation and classification) achieved from

Federal measures such as the Federal Motor Vehicle Control

Program and fuel volatility rules as well as control measures

that have been adopted and implemented by the state. This

estimate should consider emission rates, production capacities,

and other related information to clearly show that the air

quality improvements are the result of implemented controls. The

analysis should assume that sources are operating at permitted

levels (or historic peak levels) unless evidence is presented

that such an assumption is unrealistic.

4. section 110 and Part D Requirements

For the purposes of redesignation, a state must meet all

requirements of section 110 and Part D that were applicable prior

to submittal of the complete redesignation request. When

evaluating,a redesignation request, Regionsshouid not consider

whether the state has met requirements that come due undjr the

Act after submittal of a complete redesignation request.

2This is consistent with EPA's existing policy on

redesignations as stated in an April 21, 1983 memorandum titled

"Section 107 Designation Policy summary." This memorandum states

that in order for an area to be redesignated to attainment, the

State must show that "actual enforceable emission reductions are

responsible for the recent air quality improvement." This

element of the policy retains its validity under the amended Act

pursuant to section 193. [Note: other aspects of the April 21,

1983 memorandum have since been superseded by sUbsequent

memorandums; interested parties should consult with'OAQPS before

relying on these aspects, e.g. those relating to required years

of air quality data.]

3under section 175A(c), however, the requirements of Part D

remain in force and effect for the area until such time as it is

redesignated. Upon redesignation to attainment, ~the requirements

that became due under section 175A(c) after submittal of the

complete redesignation request would no longer be applicable.
for

section are

We will

5

However, any requirements that came due prior to submittal of the

redesignation request must be fully approved into the plan at or

before the time EPA redesignates the area.

To avoid confusion concerning what requirements will be

applicable for purposes of redesignation, Regions should

encourage states to work closely with the appropriate Regional

Office early in the process. This will help to ensure that a

redesignation request submitted py the State has a high . likelihood of being approved by EPA. Regions should-advise

States of the practical planning consequences if EPA disapproves

the redesignation request or if the request is invalidated

because of violations recorded during EPA's review. Under such

circumstances, EPA does not have the discretion to adjust

schedules for implementing SIP requirements. As a result, an

area may risk sanctions and/or Federal implementation plan

implementation that could result from failure to meet SIP

submittal or implementation requirements.

a. section 110 Requirements

section 110(a)(2) contains general requirements

nonattainment plans. Most of the provisions of this

the same as those contained in the pre-amended Act.

provide guidance on these requirements as ~eeded.4

b. Part DRequirements

Part D consists of general requirements applicable to all

areas whicp are designated nonattainment based on a violation of

the NAAQS •. The general requirements are followed by a series of

subparts specific to each pollutant. The general requirements

appear in sUbpart 1. The requirements relating to 03 , CO, PM-10,

S02' N02 , and Pb appear in subparts 2 through 5. In those

instances where an area is sUbject to both the general

nonattainment provisions in subpart 1 as well as one of the

pollutant-specific subparts, the general provisions may be

subsumed within, or superseded by, the more specific requirements

of sUbparts 2 through 5.

If an area was not classified under section 181 for 03 , or

section 186. for CO, then that area is only subject to the

provisions of sUbpart 1, "Nonattainment Areas in General." In

addition to relevant provisions in sUbpart 1, an 0 3 'and CO area,

which is classified, must meet all applicable requlrements in

subpart 2, "Additional Provisions for Ozone Nonattainment Areas,"

and subpart 3, "Additional Provisions for Carbon Monoxide

4General guidance regarding the requirements for SIP's may

be found in the "General Preamble to Title I of the 1990 Clean

Air Act Amendments," 57 FR 13498 (April 16, 1992).
6

Nonattainment Areas," respectively, before" the area may be

redesignated to attainment. All PM-IO nonattainment areas

(whether classified as moderate or serious) must similarly meet

the applicable general provisions of subpart 1 and the specific

PM-I0 provisions in subpart 4, "Additional Provisions for

Particulate Matter Nonattainment Areas." Likewise, S02' N0 2 , and

Pb nonattainment areas are sUbject to the applicable general

nonattainment provisions in subpart 1 as well as the more

specific requirements in sUbpart, 5, "Additional Provisions for

Areas Designated Nonattainment for Sulfur oxides, Nitrogen

Dioxide, and Leaa. ,,'

i. Section 1?2(c) Reguirements

This section contains general requirements for nonattainment

plans. A thorough discussion of these requirements may be found

in the General Preamble to Title I [57 FR 13498 (April 16,

1992)]. The EPA anticipates that areas will already have met

most or all of these requirements to the extent that they are not

superseded,by more specific Part D requirements. The

requirements for reasonable further progress, identification of

certain emissions increases, and other measures needed for

attainment will not apply for redesignations because they only

have meaning for areas not attaining the standard. The

requirements for an emission inventory will be satisfied by the

inventory requirements of the maintenance'plan. The requirements

of the Part D new source review program will be replaced by the

prevention of significant deterioration (PSD) program once the

area has been redesignated. However, in order to ensure that the

PSD progr~m will become fully effective immediately upon

redesignation, either the State must be delegated the Federal PSD

program or the State must make any needed modifications to its

rules to have the approved PSD program apply to the affected area

upon redesignation.

ii. Conformity

The State must work with EPA to show that its SIP

provisions are consistent with section 176(c)(4) conformity

requirements. The redesignation request should include"

conformity procedures, if the State already has these procedures

in place. Additionally, we currently interpret the conformity

requirement to apply to attainment areas. However, EPA has not

yet issued its conformity regulations specifying wHat areas are

sUbject to the conformity requirement. Therefore, if a State

does not have conformity procedures in place at the time that it

submits a redesignation request, the state must commit to follow

EPA'S conformity regulation upon issuance, as applic~ble. If the

State submits the redesignation request SUbsequent to EPA's

issuance of the conformity regulations, and the -conformity

requirement became applicable to the area prior to SUbmission,
7

the state must adopt the applicable conformity requirements

before EPA can redesignate the area.

5. Maintenance Plans

section 107(d)(3)(E) of the amended Act stipulates that for

an area to be redesignated, EPA must fUlly approve a maintenance

plan which meets the requirements of section 175A. A state may

submit both the redesignation request and the maintenance plan at . the same time and rUlemaking on both .may proceed on a parallel

track. Maintenance" plans may, of course, be submitted and

approved by EPA before a redesignation is requested. However,

according to sectio~ 175A(c), pending approval of the maintenance

plan and ·redesignation request, all applicable nonattainment area

requirements shall remain in place.

section 175A defines the general framework of a maintenance

plan. The maintenance plan will constitute a SIP revision and

must provide for maintenance of the relevant NAAQS in the area

for at least 10 years after redesiqnation. section 175A further

states that the plan shall contain such additional measures, if

any, as may be necessary to ensure such maintenance. Because the

Act requires a demonstration of maintenance for 10 years after an

area is redesignated (not 10 years after submittal of a

redesignation request), the State should plan for some lead time

for EPA action on the request. In other words, the maintenance

demonstration should project maintenance for 10 years, beginning

from a date which factors in the time necessary" for EPA review

and approval action on the redesignation request. In determining

the amoun~ of lead time to allow, States should consider that

section 107(d)(3)(D) grants the Administrator up to 18 months

from receipt of a complete submittal to process a redesignation

request. The statute also requires the State to submit a

revision of the SIP 8 years after the original redesignation

request is approved to provide for maintenance of the NAAQS for

an additional 10 years following the first la-year period [see

section 175A(b)].

In addition, the maintenance plan shall contain such

contingency measures as the Administrator deems necessary to

ensure prompt correction of any violation of the NAAQS [see

section 175A(d)]. The Act provides that, at a minimum, the

contingency measures must include a requirement that the state

will implement all measures contained in the nonatt~inment SIP

prior to redesignation. Failure to maintain the NAAQS and

triggering of the contingency plan will not necessitate a

revision of the SIP unless required by the Administrator, as

stated in section 175A(d).

The following is a list of core provisions that we

anticipate will be necessary to ensure maintenance of the

relevant NAAQS in an area seeking redesignation from
8

nonattainment to attainment. We therefore" recommend that states

seeking redesignation of a nonattainment area consider these

provisions. However, any final EPA determination regarding the

adequacy of a maintenance plan will be made following review of

the plan submittal in light of the particular circumstances

facing the area proposed for redesignation and based on all

relevant information. available at the time.

a. Attainment Inventory

The State should develop an att~inmeni emissions inventory

to identify the level of emissions in the area which is

sufficient to attai" the NAAQS. 5 This inventory should be

consistent with EPA's most rece{l.t guidance on emission.

inventories for nonattainment areas available at the time and

should include the emissions during the time period associated

with the monitoring data showing attainment. 6

Source size thresholds are 100 tons/year for so , NO , and

PM-10 areas, and 5 tons/year for Pb based upon 40 CFi 51.fOO(k)

and 51.322, as well' as established practice for AIRS data. ·The

source size threshold for serious PM-I0 areas is 70 tons/year

5Where the state has made an adequate demonstration that air

quality has improved as a result of the SIP (as discussed

previously), the attainment inventory will generally be the

actual inventory at the time the area attained -the standard.

6The EPA's current guidance on the PFeparation of emission

inventories for 0 and CO nonattainment areas is contained in the

following documen.fs: "Procedures for the p'reparation of Emission

Inventories for Carbon Monoxide and Precursors of Ozone: Volume

I" (EPA-450j4-91-016), "Procedures for the Preparation of

Emission Inventories for Carbon Monoxide and precursors·lof Ozone:

Volume II" (EPA-450/4-91-014), "Emission Inventory Requirements

for Ozone State Implementation Plans" (EPA-450j4-91-010),

"Emission Inventory Requirements for Carbon Monoxide

Implementation Plans" (EPA-450/4-91-011), "Guideline for

Regulatory Application of the Urban Airshed Model" (EPA~450j4-91­

013), "Procedures for Emission Inventory Preparation: Volume IV,

Mobile Sources" (EPA-450/4-81-026d), and "Procedures for

Preparing Emission Inventory Projections" (EPA-450/4-91-019).

The EPA does not currently have specific guidance on attainment

emissions inventories for S02. In lieu thereof, States are

referred to the guidance on emissions data to be used as input to

modeling demonstrations, contained in Table 9.1 of EPA's

"Guideline on Air Quality Models (Revised)" (EPA-450/2-78-027R),

July 1987, which is generally applicable to all criteria

pollutants. Emission inventory procedures and ~equirements

documents are currently being prepared by OAQPS for PM-I0 and Pbi

these documents are due for release by summer 1992.
9

according to Clean Air Act section 189(b)(3). However, the

inventory should include sources below these size thresholds if

these smaller sources were included in the SIP attainment

demonstration. Where sources below the 100, 70, and 5 tons/yearsize thresholds (e.g., areas with smaller source size

definitions) are sUbject to a State's minor source permit

program, these sources need only be addressed in the aggregate to

the extent that they result in areawide growth.

For 03 nonattainment areas, the inventory should be based on

actual "typical sumnier day" emissions of 03 precursors (volatile

organic compounds and nitrogen oxides) dur1ng the attainment

year. This will gen~rally correspond to one of the periodic

inventories required for nonattainment areas to reconcile

milestones. For CO.nonattainment areas, the inventory should be

based on actual "typical CO season day" emissions for the

attainment year. This will generally correspond to one of the

periodic inventories requ\red for nonattainment areas. ib. Maintenance Demonstration

A State may generally demonstrate maintenance of the NAAQS

by either showing that future emissions of a pollutant or its

.precursors will not exceed the level of the a~tai~m8nt inventor~,

or by modeling to show that the future mix of sources and

emission rates will not cause a violation of -th~ NAAQS. Under

the Clean Air Act, many areas are required to submit modeled

attainment demonstrations to show that proposed -reductions in

emissions will be sufficient to attain the~applicable NAAQS. For

these area~, the maintenance demonstration·' should -be based upon

the same level of modeling. In areas where no such modeling was

required, the State should be able to rely on the attainment

inventory approach. In both instances, the demonstration should

be for a period of 10 years following the redesignation.

Where modeling is relied upon to demonstrate maintenance,

each plan should contain a summary of the air quality

concentrations expected to result from application of the control

strategy. In the process, the plan should identify and describe

the dispersion model or other air quality model used to project

ambient concentrations (see 40 CFR 51.46).

In either case, to satisfy the demonstration requirement the

State should project emissions for the 10-year period following

redesignation, either for the purpose of showing that emissions

will not ~ncrease over the attainment inventory or for conducting

modeling. The projected inventory should consider future

growth, including population and industry, should be consistent

7Guidance for projecting emissions may be found in the

emissions inventory guidance cited in footnote 6.
10

with the attainment inventory, and should document data inputs

and assumptions. All elements of the demonstration (e.g.,

emission projections, new source growth, and modeling) should be

consistent with current EPA modeling guidance. 8 For 03 and CO,

the projected emissions should reflect the expected actual

emissions based on enforceable emission rates and typical

production rates.

For CO, a State should address the areawide component of the

maintenance demonstration either· by showing that future CO

emissions will not increase or by conducting areawide modeling.

Preferably, the State should carry out hot-spot modeling that is

consistent with the ~uideline on Air Ouality Models (Revised), in

order to demonstrate maintenance of the NAAQS. In particular, if

the nonattainment problem is related to a pattern of hot~spots

then hot-spot modeling should generally be conducted. However,

hot-spot modeling is not automatically required. For example, if

the nonattainment problem was related solely to stationary point

sources, or if highway improvements have been implemented and the

associated emission reductions and travel characteristics can be

qualitatively documented, then hot-spot modeling is not required.

In such cases, adequate documentation as well as the concurrence

of Headquarters is needed.

Any assumptions concerning emission rates must reflect

permanent, enforceable measures. In other.words, a State

generally cannot take credit in the maintenance demonstration for

reductions unless there are regulations in place requiring those

reductions or the reductions are otherwise shown to be permanent.

Therefore, the State will be expected to maintain its implemented

control strategy despite redesignation to attainment, unless such

measures are shown to be unnecessary for maintenance or are

replaced with measures that achieve equivalent reductions (see

additional discussion under "contingency Plan"). Emission

reductions from source shutdowns can be considered permanent and

enforceable to the extent that those shutdowns have been

reflected in the SIP and all applicable permits have been

modified accordingly.

Modeling used to demonstrate attainment may be reli$d upon

in the maintenance demonstration where the modeling conforms to

current EP~ guidance and where the state has projected no

significant changes in the modeling inputs during the intervening

time. Where the original attainment demonstration may no longer

be relied upon, states will be expected to remodel using current

8The EPA-approved modeling guidance may be found in the

following documents: "Guideline on Air Quality Models

(Revised)," OAQPS, RTP, NC (EPA-450/2-78-027R), July 1986; and

"PM-10 SIP Development Guideline," OAQPS, RTP, NC (EPA-450/2-86~

001), June 1987.
11

EPA referenced techniques. 9 This may be necessary where, for

example, there has been a change in emissions or a change in the

siting of new sources or modifications such that air quality may

no longer be accurately represented by the existing modeling.

c. Monitoring Network

Once an area has been redesignated, the state should

continue to operate an appropriate air quality monitoring

network, in accordance with 40 CFR Part 58, to verify the

attainment status" of the area. The maintenance plan should

contain provisions for continued operation of air quality

monitors .that will provide such verification. In cases where

measured mobile source parameters (e.g., vehicle miles traveled

congestion) have changed over time, the state may also need to

perform a saturation monitoring study to determine the need for,

and location of, additional permanent monitors.

d. Verification of Continued Attainment

Each state should ensure that it has the legal authority to

implement and enforce all measures necessary to attain and to

maintain the NAAQS. Sections 110(a)(2)(B) and (F) of the Clean

Air Act, .as amended, and regulations promulgated at 40 eFR

51.110(k), suggest that one such measure is the acquisition of

ambient and source emission data to demonstrate attainment and

maintenance.

Regardless of whether the maintenance demonstration is based

on a showing that future emission inventories will not exceed the

attainment'inventory or on modeling, the state submittal should

indicate how the state will track the progress of the maintenance

plan. This is necessary due to the fact that the emission

projections made for the maintenance demonstration depend on ~ssumptions of point and area source growth.

One option for tracking the progress of the maintenance

demonstration, provided here as an example, would be for the . state to periodically update the emissions inventory. In this

case, the maintenance plan should specify the frequency of any

planned inventory updates. Such an update could be based, in

part, on the annual AIRS update and could indicate new source

growth and other changes from the attainment inventory (e.g.,

changes in vehicle miles travelled or in traffic patterns). As

an alternative to a complete update of the inventory, the state

may choose to do a comprehensive review of the factors that were

used in developing the attainment inventory to show no

significant change. If this review does show a significant

change, the State should then perform an update of the inventory .

. 9See references for modeling guidance cited in footnote 8.
.-"

12

Where the demonstration is based on modelihg, an option for

tracking progress would be for the state to periodically

(typically every 3 years) reevaluate the modeling assumptions and

input data. In any event, the state should monitor the

indicators for triggering contingency measures (as discussed

below) .

e. contingency Plan

section 175Aof the Act also requires that a maintenance

plan include contingency provisions, as necessary, to promptly

correct any violation of the NAAQS that occurs after

redesignation of the" area. These contingency measures are

distinguished from those generally required for nonattainment

areas under section 172(c)(9) and those specifically required for

0 3 and co nonattairiment areas under sections 182(C)(9) and

187(a)(3), respectively. For the purposes of section 175A,

State is not required to have fully adopted contingency measures

that will take effect without further action by the State in

order for the maintenance plan to be approved. However, the

contingency plan is considered to be an enforceable part of the

SIP and should ensure that the contingency measures are adopted

expediently once they are triggered. The plan should clearly

identify the measures to be adopted, a schedule and procedure for

adoption and implementation, and a specific time limit for action

by the State. As a necessary part of the 'plan, the State should

also identify specific indicators, or triggers, which will be

used to determine when the contingency measures" need to be

implemented.

Where'the maintenance demonstration is based on the

inventory, the State may, for example, identify an "action level"

of emissions as the indicator. If later inventory updates show

that the inventory has exceeded the action level, the State would

take the necessary steps to implement the contingency measures.

The indicators would allow a State to take early action to

address potential violations of the NAAQS before they occur. By

taking early action, States may be able to prevent any actual

violations of the NAAQS and, therefore, eliminate the ne.ed on the

part of EPA to redesignate an area to nonattainment.

other indicators to consider include monitored or modeled

violations of the NAAQS (due to the inadequacy of monitoring data

in some situations). It is important to note that air quality

data in excess of the NAAQS will not automatically necessitate a

revision of the SIP where implementation of contingency measures

is adequate to address the cause of the violation. The need for

a SIP revision is sUbject to the Administrator's discretion.

The EPA will review what constitutes a contingency plan on a

case-by-case basis. At a minimum, it must require that the state

will implement all measures contained in the Part 0 nonattainment
13

plan for the area prior to redesignation [see section 175A(d)].

This language suggests that a state may submit a SIP revision at

the time of its redesignation request to remove or reduce the

stringency of control measures. Such a revision can be approved

by EPA if it provides for compensating equivalent reductions. A

demonstration that measures are equivalent would have to include

appropriate modeling or an adequate justification. Alternatively, a state might ·be able to demonstrate (through

EPA-approved modeling) that the measures are not necessary for

maintenance of the standard. In either case, the contingency

plan would have to provide for implementation of any measures

that were reduced or removed after redesignation of the area.

Summary

As stated previously, this memorandum consolidates EPA's

redesignation and maintenance plan guidance and Regions should

rely upon it as a general framework in draftinq Federal Register

notices. It is strongly suggested that tne Regional Office~

share this document with the appropriate states. This should

give the states a better understanding of what is expected from a

redesignation request and maintenance plan under existing policy.

Any necessary changes to existing Agency policy will be made

through our action on specific redesignation requests and the

review of section 175A maintenance plans for these particular

areas, both of which are sUbject to notice -and commentrulemaking

procedures. Thus, in applying this memorandum to specific

circumstances in a rulemaking, Regions should' consider the . applicability of the underlying policies to the particular facts

\'and to comments submitted by any person. If your staff members

have questions which require clarification, they may contact

Sharon Reinders at (919) 541-5284 for 0 3- and CO-related issues,

and Eric Ginsburg at (919) 541-0877 for S02-' PM-10-, and

Pb-related issues.

cc: Chief, Air Branch, Regions I-X

John Cabaniss, OMS

Denise Devoe, OAQPS

Bill Laxton, TSD

Rich Ossias, OGC

John Rasnic, SSCD

John Seitz, OAQPS

Mike Shapiro, OAR

Lydia Wegman, OAQPS
".

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

Office of Air Quality Planning and Standards

Research Triangle Park, North Carolina 27711

COpy

1JUN 1992

-

MEMORANDUM

SUBJECT: Contingency Measures for Ozone and Carbon Monoxide (CO)

Redesignations

FROM: G.T. Helms, Chief

Ozone/Carbon Monoxide Programs Branch (MD-15)

TO: Air Branch Chief, Regions I-X

Several Regions have asked for specific examples of what a

contingency plan should contain. In general, a contingency plan

should identify the measures that the State will adopt and the

factors that will determine when the measures will be adopted.

An example of this is attached. The attached example is only one

approach to the contingency plan; it is not the only approach.

If you have any further questions concerning this sUbject,

please contact Laurel Schultz at (919) 541-5511.

Attachment

OAQPS:AQMD:OCMPB:LAURELSCHULTZ:JKING:EXT. 5511:5/22/92

I • 1,\'-/ CONCURRENCES =:..~~ :'J,! - - - . OAT~ ···~iiii~i·· . - - .

I!P4 P_ 1320-1 02.70)
ATTACHMENT

Example of Ozone contingency Plan Provisions:

The following provisions might be included in a contingency plan:

1) Inclusion of several potential scenarios that could

trigge~ implementation of the contingency plan - ...•

A state may choose to establish a number of indicators to

trigger contingency measures. For example, one scenario for

ozone may be an increase in volatile organic compounds (VOC)

emissions which exceeds a predetermined "action line" level

(encroaching into the emission margin of safety), but does not

necessarily produce ozone violations. Another situation,

regardless of the actual VOC emissions, may involve actual

violations of the national ambient air quality standards (NAAQS)

for ozone. For CO, the trigger will probably have to be based on

ambient concentrations, but a specified emission level may be

used as a supplement in some situations.

2) structured levels of measures to be implemented due to

the extent of the problem -

Once the state has established the indicators and trigger

levels, it may identify specific measures to correspond to each

of the triggers. For example, if the first scenario involving

ozone occurs with no violations, then certain defined measures

may be taken, such as: (a) requirement for VOC emission offsets

for new and modified major sources at 1.1 to 1, as required for

"marginal" areas under the Clean Air Act; (b) completion of

comprehensive VOC emission inventory; and (c) implementation of

one or more transportation control measures sufficient to achieve

at least 0.5 percent reduction in actual areawide VOC emissions.

Where violations do occur, additional defined measures may be

implemented, such as stage II vapor recovery or enhanced

inspection/maintenance program. Finally, if the above controls

still are not successful in curtailing violations of the ozone

NAAQS, additional measures may be employed (e.g., requirement

for VOC emission offsets for new and modified major sources at

1.15 to 1, as required for "moderate" areas pursuant to the Act).

Even more extreme measures may be implemented, such as requiring

VOC controls on minor new sources (less than 100 tons) and

requiring reasonably available control technology on sources

covered by new Environmental Protection Agency (EPA) control

techniques guidelines documents. As a last resort, if the above

measures fail to bring the area back into attainment, the state

could commit in its contingency plan that it will request

designation to nonattainment at the appropriate classification.

This last measure is not essential, as EPA has the authority

under section 107 to unilaterally redesignate an area.
2

3) Detailed description of particular measures to be

undertaken -

The state should provide as much detail as possible

concerning the contingency measures to be implemented. For

example, if transportation control measures are included, the

plan s~ould specify the levels to which they will apply. For

instance, such specifications could include trip reduction

programs for employers of more than number of employees that

will mandate a specified vehicle occupancy rate; transit

improvements such as purchase of y number of buses to be placed

on specified routes; traffic flow improvements (e.g., no left

turns at specified blocks); alternative fuels programs for fleet

vehicle operations over a specified size fleet; vehicle antitampering programs; and other innovative transportation control

measures.

4) Discussion of preparatory actions necessary before actual

implementation of certain measures -

The plan should identify the procedure to be used to adopt

and implement the contingency measures to ensure promptness. For

instance, before implementation of stage II vapor recovery,

affected individuals/industries need proper notification. Local

and state officials should be well informed of any changes. An

official notification scheme should be included as part of the

contingency plan. In addition, the state should submit a .

schedule of when each of these elements of the procedure will be

completed. The schedule should also account for the time needed

by the state to adopt specific measures.
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

 Office of Air Quality Planning and Standards 

 Research Triangle Park, North Carolina 27711 

 June 18, 1990 

MEMORANDUM 

SUBJECT: Ozone and Carbon Monoxide Design Value Calculations 

FROM: William G. Laxton, Director 

 Technical Support Division (MD-14) 

TO: See Below 

 In discussions related to the Clean Air Act legislation, design 

values for ozone and carbon monoxide are receiving particular 

attention. Previously, it sufficed to designate areas as either 

attainment or nonattainment but now areas will be further classified 

into different categories based upon the magnitude of the appropriate 

design value. This additional classification step places added 

emphasis on the need to accurately determine these design values. The 

classification will be done according to concentration cutpoints, and 

on a schedule, specified in the legislation. 

 Obviously, once this process is set in motion we will be working 

very closely with you to develop these design values. However, I 

thought it would be appropriate to reiterate our design value 

computation procedures in advance to help people anticipate the types 

of data review questions that may arise. The computation procedures 

stated here are consistent with our previous methods. There are 

differences between the procedures for ozone and carbon monoxide 

because the National Ambient Air Quality Standard (NAAQS) is 

structured in terms of expected exceedances while the carbon monoxide 

NAAQS uses the older "once per year" format. The most apparent 

difference is that the CO design values are based upon 2 years of data 

while design values for ozone use 3 years. Another difference is that 

the ozone NAAQS uses the daily maximum ozone value while the CO NAAQS 

considers running 8-hour averages so that, even though they must be 

non-overlapping, it is possible to have more than one CO exceedance per 

day. Because of these differences, it is convenient to discuss each 

pollutant separately. With respect to terminology, you may hear the CO 

design value approach referred to as "the highest of the second highs', 

while the ozone design value is frequently simplified as "the fourth 

high in 3 years." 

 One point to remember is that all locations within an area have to 

meet the standard (NAAQS). Therefore, when we do our evaluations, we 

look at each individual site to make sure that every site meets the 

standard. A separate design value is developed for each site that does 

not meet the NAAQS, and the highest of these design values is the 

design value for the area. 

 

Page 2 

Carbon Monoxide 
 CO design values are discussed in terms of the 8-hour CO NAAQS, 

rather that the 1-hour NAAQS, because the 8-hour NAAQS is typically the 

standard of concern. However, a 1-hour design value would be computed 

in the same manner. For 8-hour CO, we simply look at the maximum and 

second maximum (non-overlapping) 8-hour values at a site for the most 

recent 2 years of data. These values may be readily found on an AIRS 

AMP450, "Quick Look", printout. Then we choose the highest of the 

second highs and use this as our design value for that site. We then 

look at all design values within an area and the highest of these 

serves as the design value for the area. Note that, for each site, 

individual years of CO data are considered separately to determine the 

second maximum for each year - CO data are not combined from different 

years. It is probably worth commenting on this. The CO NAAQS requires 

that not more than one 8-hour average per year can exceed 9 ppm 

(greater than or equal to 9.5 ppm to adjust for rounding). We evaluate 

attainment over a 2-year period. If an area has a design value greater 

that 9 ppm, it means there was a monitoring site where the second 

highest (non-overlapping) 8-hour average was greater that 9 ppm in at 

least 1 year. Therefore, there were at least two values above the 

standard during 1 year at that site and thus the standard was not met. 

 Hypothetical Case (two CO sites in an area) 

 (8-Hour Averages) 

 MAX 2nd High 

 SITE 1 1987 14.6 8.9 

 1988 13.9 10.9 

 10.9 is the Design Value 

 for Site 1 

 (8-Hour Averages) 

 MAX 2nd High 

 SITE 2 1987 12.2 11.1 

 1988 10.8 10.4 

 11.1 is the Design Value 

 for Site 2 

 11.1 ppm would be the design value for the area. 

Ozone 

 The form of the ozone NAAQS requires the use of a 3-year period to 

determine the average number of exceedances per year. In its simplest 

form, the ozone standard requires that the average number of 

exceedances over a 3-year period, cannot be greater than 1.0. An area 

with four exceedances during a 3-year period, therefore, does not meet 

the ozone standard because four exceedances in 3 years averages out to 

more than once per year. Now, if the fourth highest value was equal to 

the level of the ozone standard, i.e. 0.12 ppm, then the area would 

have no more than three exceedances during the 3-year period and the 

average number of exceedances per year would not be greater 

3 

 

Page 3 

than one. This assumes no missing data and is how the fourth high 

value in 3-years came to be used as the design value. Actually, an 

adjustment is specified in the ozone NAAQS to account for missing data 
in determining the expected exceedances for ozone. Because of 

considerations associated with control strategy modeling, the following 

basic approach for ozone design values has been in use since 1981. If 

there are 3 complete years of ozone data, then the fourth highest daily 

maximum during the 3-year period is the data, then the fourth highest 

daily maximum during the 3-year period is the design value for that 

site. If only 2 complete years of data are available, then the third 

highest is used and, if only one complete year is available, then the 

second highest is used. In this approach, a year of ozone data is 

considered complete if valid daily maximums are available for at least 

75 percent of the ozone season. Note that because of the form of the 

ozone NAAQS, data are combined over multiple years but they are not 

combined from different sites. 

 Hypothetical Case (two O3 sites in an area, each year at 

 least 75% complete) 

 FOUR HIGHEST DAILY MAXIMUM VALUES 

 Max 2nd Hi 3rd Hi 4th Hi 

 SITE 1 1986 .127 .123 .122 .110 

 1987 .129 .124 .121 .116 

 1988 .142 .136 .134 .115 

 The design value for Site 1 is 0.129 ppm, the fourth highest 

 daily maximum value during the three year period. 

 FOUR HIGHEST DAILY MAXIMUM VALUES 

 Max 2nd Hi 3rd Hi 4th Hi 

 SITE 2 1986 .110 .100 .095 .090 

 1987 .110 .100 .095 .090 

 1988 .180 .175 .160 .110 

 

 The design value for Site 2 is 0.110, the fourth highest 

 value during the three year period. 

 0.129 ppm would be the design value for the area. 

 There are a few additional comments warranted on the ozone 

example. First, note that data from each site was treated 

independently in computing the design value for that site. Assuming no 

missing data, the second site would meet the ozone NAAQS but the area 

would not because the other site shows that the NAAQS is not being met. 

Also, it should be noted that the high 

 

Page 4 

values for a year are considered even if the data for that year did not 

satisfy the 75 percent data completeness criterion. For example, if a 

site had 2 years of data that met the 75 percent data completeness 

requirement and 1 year that did not, then the third highest value 

during the 3-year period would be the design value because there were 
only 2 complete years of data but the data from all 3 years would be 

considered when determining the third highest value. This ensures that 

valid high ozone measurements in a particular year are not ignored 

simply because other data in that year were missing. When computing 

data completeness, the number of valid days can be increased to include 

days that may be assumed to be less than the standard level as stated 

in the ozone NAAQS. Also, for new sites that have just come on line, 

the 75 percent data completeness requirement for the start-up year may 

be applied beginning with the first day of actual monitoring as long as 

the data set is at least 75 percent complete for June through August. 

 A final practical complication that must be addressed in 

determining ozone design values is the case where a site reports data 

but has no year that meets the 75 percent data completeness 

requirement. Admittedly, this is an unusual situation but, for the 

sake of completeness, it needs to be addressed. At the same time, 

however, the reason for this consistent data completeness problem 

should be examined because ozone monitoring data completeness is 

typically greater that 90 percent. In general, if a site has no 

complete years of data and fewer than 90 days of data during the 3-year 

period, the design value will be determined on a case by case basis. 

In such cases, the data base is so sparse that it would be extremely 

difficult to describe general rules that would apply and a careful 

evaluation would have to be made to determine why this situation 

occurred and what is the most appropriate way to use the data. For a 

site without a single complete year of data but at least 90 days of 

data during the 3-year period, the following steps are followed in 

determining the ozone design value: 

 1. Divide the number of valid daily maximums during the 3-year 

 period by the required number of monitoring days per year. 

 As noted earlier, the number of valid days can be increased 

 by including the number of days that may be assumed to be 

 less than the standard level as specified in the ozone NAAQS. 

 2. Add 1.0 to the above total and then use the integer portion 

 of the result as the rank of the design value. 

 These steps are not as complicated as they may initially appear. 

For example, suppose a site with a required ozone monitoring season of 

214 days each year reports 0, 121, and 130 valid days of ozone data 

during the 3-year period. Step 1 would give (0+121+130)/214=1.17. In 

step 2, 1.0 is added to this total giving 2.17. The integer portion of 

2.17 is 2 and so the design value is the second highest value during 

the three year period. Again, this type of situation should not occur 

that often and the reasons for the data completeness problems should be 

identified. 

 When discussing data completeness for ozone, it is important to 

recognize that monitoring sites are occasionally discontinued for valid 

 

Page 5 

practical reasons. In such cases, if data are available from another 

site that is representative of the same situation, then data from the 

discontinued site may be superceded by data from the other site. The 

intent is to ensure that a single year of data from a monitor that was 

discontinued 2 years ago, does not dictate the design value if data are 
available from another, equally representative, site. This is not 

intended to eliminate the missing data penalty when a site is 

discontinued and there is no data available from a similar monitor. 

 I have not discussed certain basic data handling 

conventions, such as computing 8-hour CO averages with missing 

data, determining the non-overlapping second maximum 8-hour 

average, or the definition of a valid daily maximum 1-hour ozone 

daily maximum. All of these conventions have been in place since 

the 1970's and are routinely incorporated into AIRS outputs so I 

have not bothered to discuss these points. 

Addressees: 

Director, Environmental Services Division, Regions I-VIII, X 

Director, Office of Policy and Management, Region IX 

Director, Air Management Division, Region III 

Director, Air and Waste Management Division, Region II 

Director, Air, Pesticides and Toxics Management Division, Regions 

 I and IV 

Director, Air and Radiation Division, Region V 

Director, Air, Pesticides and Toxics Division, Region VI 

Director, Air and Toxics Division, Regions VII, VIII, IX, and X 

cc: J. Calcagni (MD-15) 

 R. Campbell (MD-10) 

 T. Curran (MD-14) 

 D. DeVoe (ANR-443) 

 J. Farmer (MD-13) 

 T. Helms (MD-15) 

 W. Hunt (MD-14) 

 S. Meiburg (MD-11) 

 R. Ossias (LE-132A) 

------------------------- end of original document ----------------- 

Note to reader: 

This copy of the Laxton memo is a retyped version of the original. As 

a result, the page breaks had to be forced after the last word on each 

page on the original document. 
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

Office of Air Quality Planning and Standards .

Research Triangle Park, North Carolina 27711

COpy

:3 0APR 1992

MEMORANDUM

SUBJECT: Maintenance Plans for Redesignation of Ozone and Carbon

Monoxide Nonattainment Areas

FROM: G.T. Helms, Chief

Ozone/Carbon Monoxide Programs Branch (MD-15)

TO: Air Branch Chief, Regions I-X

The purpose of this memorandum is to provide clarification

of an issue related to maintenance plans for ozone and carbon

monoxide. This issue concerns the maintenance demonstration and,

in particular, the projection of emissions. In order to make the

review of the demonstration easier for both EPA Regions and

Headquarters, State submittals should clearly show the procedure

used to project future emissions. There has been some concern

that if the procedure is not clear, it is very difficult to

evaluate the demonstration. The procedure used should be

consistent with the guidance contained in the EPA document

"Procedures for Preparing Emission Inventory Projections" (EPA450/4-91-019). According to this document, projected emissions

should reflect the allowable emission rate and the expected

actual production or activity level.

If you have any further questions concerning this subject,

please contact Laurel Schultz at (919) 541-5511.