Approval and Promulgation of Air Quality Implementation Plan; Colorado; PM10 and NOINFX/INF Mobile Source Emission Budget Plans for Denver, CO

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[CO-001-0022 and CO-001-0023; FRL-5981-4]

Approval and Promulgation of Air Quality Implementation Plan;

Colorado; PM10 and NOX Mobile Source Emission Budget Plans

for Denver, CO

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is approving the State Implementation Plan (SIP) revisions

submitted by the Governor of Colorado on July 18, 1995 and April 22,

1996. The PM10 and NOX emissions budgets contained in these

SIP revisions are used to assess the conformity of transportation

plans, transportation improvement programs and, where appropriate,

federally funded projects for the applicable periods required by EPA's

conformity rules. EPA originally proposed approval of the two emissions

[[Page 15295]]

budget SIPs on October 3, 1996. Based upon comments received on that

proposal, EPA published a second proposal on August 5, 1997, seeking

additional input on certain issues. In reaching its final decision to

approve the July 18, 1995 and April 22, 1996 PM10 and NOX

SIP submittals, EPA has considered the comments it received on both its

October 3, 1996 and August 5, 1997 Federal Register documents.

EFFECTIVE DATE: This action is effective on April 30, 1998.

ADDRESSES: Copies of the State's original submittals, copies of

comments received on both the October 3, 1996 and August 5, 1997

proposals and other information are available for inspection during

normal business hours at the Air Program, Environmental Protection

Agency, Region VIII, 999 18th Street, Suite 500, Denver, Colorado

80202-2466. Copies of the State documents relevant to this action are

available for public inspection at the Colorado Department of Public

Health and Environment, Air Pollution Control Division, 4300 Cherry

Creek Drive South, Denver, Colorado 80222.

FOR FURTHER INFORMATION CONTACT: Callie Videtich, EPA Region

VIII,(303)312-6434.

SUPPLEMENTARY INFORMATION:

I. Background

On March 30, 1995, the Governor of Colorado submitted a SIP

revision for Denver for PM10 that included attainment and maintenance

demonstrations. In making that submittal, the Governor requested that

EPA not act on the motor vehicle emissions budgets (also referred to as

mobile source emissions budgets) for PM10 and NOX contained

in Chapter XI of the PM10 SIP element. Motor vehicle emissions budgets

are used under EPA regulations for making transportation related

conformity determinations as required by section 176(c) of the Clean

Air Act (CAA or Act). EPA's transportation conformity rule provides

that these budgets establish a cap on motor vehicle-related emissions

which cannot be exceeded by the predicted transportation system

emissions in the future unless the cap is amended by the State and

approved by EPA as a SIP revision and attainment and maintenance of the

standard can be demonstrated.

On July 18, 1995 and April 22, 1996, the Governor submitted SIP

revisions for Denver that included additional motor vehicle emissions

budgets for PM10 and NOX. EPA proposed approval of both of

these emissions budgets on October 3, 1996 (61 FR 51631) along with the

Denver PM10 SIP. Following a 60-day public comment period, EPA

finalized approval of the Denver PM10 SIP on April 17, 1997 (62 FR

18716). At that time, EPA did not take final action on the emissions

budget submittals in order to more thoroughly consider comments

received on the proposals during the public comment period. EPA

subsequently decided to seek additional public comment regarding the

budget submittals and, on August 5, 1997, published a second notice of

proposed rulemaking to take comment on certain issues raised by

commentors on the October 3, 1996 notice of proposed rulemaking.

Specifically, EPA sought additional comment on the following issues:

Whether Colorado met the notice and public hearing requirements of the

Clean Air Act in adopting the PM10 emissions budget; whether Colorado

adequately considered growth in non-mobile sources in setting the

emissions budgets; and whether Colorado should have identified a

separate NOX budget in 1998 (the maintenance year) of 102.7

tons per day, to maintain consistency with the maintenance

demonstration. For a more complete description of EPA's request for

additional comments, please see EPA's August 5, 1997 notice of proposed

rulemaking at 62 FR 42088.

II. Response to Public Comments

In this notice, EPA is taking final action and addressing comments

relating to its October 3, 1996 and August 5, 1997 notices of proposed

rulemaking. Generally, EPA has addressed comments on each notice

separately. Where this is not the case, EPA has so indicated.

A. October 3, 1996 Proposal: The following numbered paragraphs

contain summaries of the comments received on the October 3, 1996

notice of proposed rulemaking. Each comment summary is followed by

EPA's response.

1. The PM10 budget that the Governor submitted on July 18, 1995

includes permanent budgets of 54 and 60 tons. However, the Colorado Air

Quality Control Commission's (AQCC) rule provided that these budgets

would expire in 1998. Since the legislature did not eliminate the 1998

expiration of these budgets, rulemaking by the AQCC would have been

required to eliminate the 1998 expiration. The AQCC did not conduct

such rulemaking, and therefore, the permanent 54 and 60 ton budgets

that the Governor submitted are without authority and the notice and

hearing requirements of the CAA were not met.

This commentor augmented his comments on this point in response to

EPA's August 5, 1997 notice, as follows: The legislature did not even

mention, and therefore did not change or delete, the sunset language

contained in section C.4. of the AQCC's budget rule. Nor does S.B. 95-

110 specify what the text of the rule shall be or repeal or limit the

Commission's authority to revise the emission budgets. Because neither

the legislature nor the AQCC legally amended section C.4. of the rule

submitted to EPA, section C.4. remains a part of the rule, and EPA must

approve all or none of the rule. Also, other entities at the State

level lack authority to submit part of the AQCC's rule and omit other

parts. Only the AQCC or the legislature, following proper notice and

hearing procedures, had this authority.

EPA Response: Contrary to the commentor's assertion, EPA believes

the Colorado legislature, through its passage of Colorado S.B. 95-110,

did eliminate the 1998 expiration (or sunset) of the 54 and 60 ton

budgets. In EPA's view, the legislature specifically eliminated the

reversion to a 44 ton budget from the SIP revision and designated the

60 ton budget as the budget that would apply in the future for purposes

of federal transportation conformity. For example, the language of S.B.

95-110 reads as follows:

``The revisions to the Denver element of the PM10 State

Implementation Plan adopted by the Commission on February 16, 1995,

which contain a sixty tons-per-day PM10 mobile source emissions

budget which expires January 1, 1998, and reverts to a forty-four

tons-per-day budget, are amended to provide that such forty-four

tons-per-day reversion shall not be a part of the state

implementation plan * * * The sixty tons-per-day emissions budget

shall, unless modified by the Commission through rule-making, apply

for federal transportation conformity and is included in the State

Implementation Plan only as required by the federal Act.''

This language makes clear that the legislature intended that there

would be no reversion to a budget of 44 tons per day. Given this, the

commentor's reading appears to be inconsistent with the legislative

intent because such reading would result in the expiration of the 54

and 60 ton budgets on January 1, 1998 and their replacement with the 44

ton budget.

In addition, the legislature was explicit that the 60 ton budget

should apply for the purposes of federal transportation conformity. The

commentor reads this directive out of the legislation by focusing (in

his comments on both of EPA's notices) on the second clause of the

statute, which states ``and is included in the State Implementation

Plan only as required by the federal Act.'' The commentor

[[Page 15296]]

interprets this to mean that the legislature left it to the AQCC to

determine whether a budget was necessary to meet Clean Air Act

requirements.

Concluding that no budget is required to meet nonattainment area

SIP requirements, the commentor concludes that the legislature would

not have wanted the budget in the SIP. However, EPA believes the better

reading is that the legislature was indicating that the budget would be

part of the SIP as necessary for it to be used for federal

transportation conformity purposes, and that the legislature was not

leaving it to the AQCC to decide whether the budget was required by the

CAA. In this regard, it is noteworthy that the legislature used the

present tense--the 60 ton budget ``is included in the State

Implementation Plan * * * '' (emphasis added.) Under EPA's conformity

rule, the budget may not be used unless it is part of a submitted SIP.

In this sense, there is a mandate in EPA's rule that the budget be part

of the SIP prior to use for conformity purposes, and it is reasonable

to read Colorado S.B. 95-110 as mandating the use of the 60 ton budget.

EPA does not believe the legislature had to specify new rule

language in order to amend the SIP. The State legislature does not

adopt rules, and thus, there was no need for the legislature to specify

replacement rule language. It is also irrelevant that the legislature

did not repeal or limit the AQCC's authority to revise the emission

budgets. The legislature was indicating that the 60 ton budget would

apply unless modified by the AQCC through rulemaking at some future

date. The legislature was not providing that the 60 ton budget would

only apply if endorsed by the AQCC through rulemaking.

Comments submitted by the Colorado Attorney General's Office

support EPA's reading of the legislation. See February 13, 1997 letter

signed by Frank Johnson. EPA believes it is reasonable to accord the

interpretation of the Attorney General's Office some deference given

that it is State legislation and not federal law that is at issue.

Although section 25-7-124(1) provides that the AQCC is the

regulatory entity under Colorado law with authority to adopt SIP

revisions, EPA believes the legislature retains the authority to adopt

SIP revisions in a given instance. That is what the legislature did

through the passage of S.B. 95-110.

2. Submission of the 54 and 60 ton budgets violates State law

because State law prohibits submission to EPA of measures not required

by the CAA. Specifically, C.R.S. sections 25-7-105(1)(a)(III) and 25-7-

105.1(1) prohibit the submission of rules or requirements not required

by the federal act. Motor vehicle emission budgets are not required by

the CAA and therefore, the 54 and 60 ton budgets were not lawfully

submitted to EPA.

EPA Response: As a preliminary matter, EPA is not convinced that it

should or can take cognizance of the State's compliance or lack thereof

with C.R.S. section 25-7-105.1(1). It is well-established in case law

under the CAA that EPA must approve a SIP submission if it meets the

minimum requirements of section 110 and other relevant sections of the

CAA and does not otherwise conflict with the CAA. See, e.g., Union

Elec. Co. v. E.P.A., 96 S.Ct. 2518 (1976). Even if the State should not

have submitted the 54 and 60 ton budgets to EPA under State law,

nothing in C.R.S. section 25-7-105.1(1) suggests that the State will be

unable to implement or enforce the budgets. Thus, there is no apparent

conflict with the requirements of section 110(a)(2)(A) or (E) of the

CAA. To the extent C.R.S. section 25-7-105.1(1) purports to restrict

what constitutes part of the federally enforceable approved SIP, EPA

believes the State legislature lacks the authority to amend the

relevant sections of the CAA and the Administrative Procedures Act with

respect to SIP approval. The burden is on the State to comply with

C.R.S. section 25-7-105.1(1), and EPA should not be forced to assume

that burden. See Union Elec. Co. v. E.P.A., 96 S.Ct. 2518, 2528-2529

(1976). If the commentor believed the State violated C.R.S. section 25-

7-105.1(1), EPA believes the commentor's recourse would have been to

challenge the State's submission of the budgets in State court. It is

not EPA's role to assure compliance with this State law.

Notwithstanding the foregoing, EPA believes the State legislature

issued a specific directive in this case that the 60 ton budget would

apply for purposes of conformity determinations. See EPA's response to

comment II.A.1., above. Thus, even if the commentor is correct that

these budgets were not otherwise required by the CAA and thus, normally

could not have been properly submitted by the State pursuant to C.R.S.

section 25-7-105.1(1), the legislature had the authority to disregard

its general restriction on submitting SIPs not required by the CAA (as

set forth in C.R.S. section 25-7-105.1(1)) and to adopt and require the

use of the 60 ton budget. In EPA's view, the legislature's specific

directive regarding the 60 ton budget overrides the more general

proscription contained in C.R.S. section 25-7-105.1(1).

3. The motor vehicle emissions budget (MVEB) does not provide for

attainment of the NAAQS. Specifically, the 60 ton budget will result in

NAAQS violations at numerous receptor areas unless emissions are

reduced in those receptor areas below the levels allowed by the 60 ton

regional budget. The regional budget should reflect the values

necessary to show attainment in areas where the 60 ton budget would

result in NAAQS violations. Also, values necessary to show attainment

for areas that would otherwise violate should be used to establish

subregional budgets for those areas. The CAA does not allow the

substitution of future dispersion modeling for the setting of

appropriate emissions budgets.

EPA Response: Contrary to the commentor's assertion, the 60 ton

budget already reflects the necessary emissions reductions to show

attainment in all of the receptor grids. This is described in the SIP

itself and the October 19, 1995 Kevin Briggs 1 memo that the

commentor provided with his comments. According to the Kevin Briggs

memo, the uncontrolled 2015 scenario would result in mobile source

emissions of 68 tons per day with NAAQS violations in a number of

grids. The State reduced emissions sufficiently in the violating grids

to model attainment in those grids. After making these reductions, the

State summed the emissions from all grids and arrived at a budget of 60

tons.

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\1\ Mr. Briggs is a modeler in the Technical Services Program,

Air Pollution Control Division, Colorado Department of Public Health

and Environment.

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For purposes of responding to the comment, EPA will assume that the

commentor meant that the State had not adopted control measures in the

SIP that would achieve the 8-ton reduction (from 68 to 60 tons per day)

in the violating grids in 2015. The Act clearly requires adopted,

enforceable control measures as needed to support attainment and

maintenance demonstrations required by Part D of the Act. However, as

discussed in the preamble to the recently-adopted revisions to the

conformity rule (62 FR 43787, August 15, 1997), EPA believes that it

has the flexibility to approve budgets for years beyond the required

attainment or maintenance SIP for transportation conformity purposes

based on less rigorous demonstrations than are required for these SIPs.

In particular, EPA believes it has the authority to approve budgets for

years beyond the attainment or maintenance SIP based in

[[Page 15297]]

part on enforceable commitments in the SIP to adopt specific controls

in the future, or on commitments in the SIP to adopt offsetting

emission reductions in the future, as necessary to produce the required

emissions reductions.

In this case, the MVEB SIP goes beyond a simple commitment to adopt

any needed controls or reductions in the future, because the

requirement for dispersion modeling carries with it a mandate for

adoption of any future controls necessary to provide for attainment of

the NAAQS. DRCOG must achieve the adoption of or obtain enforceable

commitments for any control measures necessary to ensure that

dispersion modeling for each conformity determination shows no

violations of the NAAQS prior to making a conformity determination.

This approach to the adoption of controls has two advantages: First, it

is self-enforcing (if the dispersion modeling shows violations, DRCOG

cannot adopt transportation plans and TIPs); second, it requires a

reassessment of control strategies each time a conformity determination

is carried out, rather than a one-time effort to adopt controls in

advance which may later become obsolete due to changes in the location

or magnitude of emissions (and thus, modeled violations). EPA believes

that the SIP's requirement for dispersion modeling and future adoption

of necessary controls satisfactorily complies with the policy options

expressed at 62 FR 43787 for budgets for years beyond the attainment or

maintenance demonstration, and is approving this requirement and the 60

ton budget for Denver. EPA would not approve the 60 ton budget for

Denver without its companion modeling requirement and the associated

requirement for adoption of controls prior to each conformity

determination. It should also be noted that the State commits in the

SIP to adopt any control measures relied on for future conformity

determinations into the SIP if necessary to demonstrate continued

maintenance of the standard. See EPA's response at II.A.4., below.

The commentor is correct that the State did not establish

subregional budgets. However, EPA's regulations do not require that an

area establish subregional budgets. The preamble to EPA's November 24,

1993 conformity rule states, ``The SIP may specify emissions budgets

for subareas of the region, provided that the SIP includes a

demonstration that the subregional emissions budget, when combined with

all other portions of the emissions inventory, will result in

attainment and/or maintenance of the standard.'' 58 FR 62196 (emphasis

added.) This language makes clear that the establishment of subregional

budgets is optional.

Regarding the use of dispersion modeling, EPA agrees that the Act

precludes the use of dispersion modeling as a substitute for an

emissions budget test. However, EPA's conformity rule did not

anticipate situations where a regional dispersion modeling analysis

would be used in addition to an emissions budget test. EPA does not

believe that such an application of dispersion modeling is precluded by

either the Act or the conformity rule. As a practical matter,

dispersion modeling in conjunction with an emissions test is at least

as protective as establishing and using subregional budgets, because in

dispersion modeling a certain target level of emissions has to be met

in each grid in order for each grid to show attainment.2

Even if subregional budgets were adopted, it is quite likely that they

would not be developed for each grid. In such a case, it might be

possible to show conformity using subregional budgets in cases when it

would not be possible using dispersion modeling.

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\2\ In this case, the SIP requires that the Denver Regional

Council of Governments (DRCOG) support each conformity determination

with a dispersion modeling analysis that shows that each grid in the

modeling domain will be in attainment, considering the emissions

expected from implementation of the transportation plan or

Transportation Improvement Program (TIP). If the modeling analysis

shows that emissions reductions are needed in any locations in order

to provide for future maintenance of the NAAQS, it is incumbent upon

DRCOG to identify and ensure implementation of any measures needed

to provide those reductions. Thus, DRCOG must satisfy two tests to

demonstrate conformity: Compliance with the 60 ton budget, and a

dispersion modeling analysis showing no violations.

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The requirement for dispersion modeling in addition to a budget

test is certainly more protective of the NAAQS than the budget-only

process envisioned by the conformity rule. The conformity rule only

requires the identification of and compliance with a region-wide

budget. It is conceivable that an area could show conformity to a

region-wide budget and still have localized violations of the NAAQS

because growth in emissions occurs in different areas than anticipated.

In a dispersion modeling approach, these same localized violations of

the NAAQS would preclude a conformity finding.

In summary, the SIP's requirement for a region wide budget in

combination with dispersion modeling clearly meets the minimum

requirements of the conformity rule, and is at least as protective of

the NAAQS as subregional budgets would be.

This commentor also included comments indicating that the PM10 SIP

does not include necessary and/or enforceable control measures that

will lead to attainment and maintenance of the NAAQS. In particular,

the commentor indicated that VMT growth was higher than the SIP

anticipated and that the SIP contained no measures to ensure VMT would

remain at the SIP-anticipated levels. EPA responded to these comments

when it approved the PM10 SIP and will not repeat the comments or

responses here. See 62 FR 18716 (April 17, 1997). For purposes of this

notice, EPA would add that it does not believe Congress intended,

through section 176 of the CAA, to change the way in which States must

conduct attainment or maintenance demonstrations. As noted in the April

1997 notice, EPA believes that it may allow a reasonable margin of

error for VMT estimates in attainment and maintenance demonstrations,

and EPA concludes that no different result should be required for

purposes of establishing conformity-related motor vehicle emissions

budgets. It should also be noted that any increased VMT will have to be

taken into account in any future conformity determinations, and will

ultimately make it harder to demonstrate conformity.

4. The submitted MVEB unlawfully attempts to transfer authority to

adopt and implement control measures. The commentor objects to the 60

ton budget because the SIP gives DRCOG the responsibility for

identifying any necessary controls to achieve emission reductions

needed to demonstrate conformity. The commentor believes that this is a

delegation of responsibility from the AQCC to DRCOG, in violation of

the Act and State law. The commentor further states that any such

controls are without legal authority and may not be treated as part of

the SIP or be given emissions reduction credit for purposes of

conformity.

EPA Response: EPA's conformity rule envisions situations where

regulatory and non-regulatory control measures may be needed to provide

emissions reductions for a conformity determination. Here, the AQCC is

not delegating its authority to adopt control measures, only to

identify them. If any measures identified as necessary by DRCOG require

a State regulation in order to be implemented (for example, a revision

to the I/M or oxygenated fuels program regulations), the AQCC would

still need to adopt such regulation or regulation revision pursuant to

applicable State law, or meet one of the other requirements in 40 CFR

93.122(a)(3), before DRCOG could take

[[Page 15298]]

credit for these emissions reductions in its conformity determination.

However, the conformity rule does not require all regulatory

control measures needed for a conformity determination to be

incorporated into the SIP, as the commentor asserts. Also, not all

control measures for conformity purposes require a regulation in order

to be implemented, such as changes in localized street sanding and

sweeping practices. EPA is satisfied with DRCOG's current practice of

obtaining commitments from local entities to implement non-regulatory

control measures and incorporating these commitments into its

conformity determinations, just as it obtains commitments from local

entities to implement transportation improvement projects during the

time frame of the plan and TIP.

It is also worth noting that the SIP, at page XI-9, states, ``Any

control measure relied on for a conformity determination shall be

included in a revised attainment or maintenance SIP unless it is not

necessary to demonstrate attainment or maintenance of the standard.''

EPA views this as a commitment on the part of the State to adopt any

measures which are necessary to show continued attainment and

maintenance of the standard.

5. The mobile source emissions budgets will ensure that future

regional transportation plans and programs will continue to help the

region attain and maintain the PM10 standard. Additionally, the budgets

are entirely consistent with the conformity provisions of the Clean Air

Act Amendments of 1990 and EPA guidance.

EPA Response: EPA agrees that the budgets are consistent with the

CAA's conformity requirements.

6. Enforceable budgets that would have reduced emissions volumes in

the region were agreed to in February 1995, but the intercession by the

legislature reduced these to little more than a suggestion.

EPA Response: EPA agrees that the legislature changed the PM10

budgets. However, EPA believes the budgets are consistent with the

requirements of the CAA and EPA's conformity rule, as described in more

detail above.

B. The Colorado Attorney General's Office submitted comments in a

letter dated February 13, 1997, signed by Frank Johnson, Assistant

Attorney General, that respond to several of the comments described in

Section II.A., above. The following numbered paragraphs contain

summaries of the relevant comments from Mr. Johnson's February 13, 1997

letter. Each comment summary is followed by EPA's response.

1. The Colorado legislature amended the SIP to eliminate the

reversion to a 44 ton PM10 budget and to specify a 60 ton PM10 budget.

The language of C.R.S. section 25-7-105(1)(a)(III) itself and the

legislative history of the statute indicate that the legislature

intended a 60 ton PM10 budget to apply for purposes of federal

conformity. Thus, no further rulemaking action by the AQCC was

necessary.

EPA Response: EPA agrees with this interpretation of C.R.S. section

25-7-105(1)(a)(III) and believes the interpretation is entitled to

deference.

2. The references to the 60 ton budget in C.R.S. section 25-7-

105(1)(a)(III) include the smaller emissions budgets for the years

before the 60 ton budget applies. The Colorado legislature used ``sixty

tons-per-day emissions budget'' as a shorthand to describe the interim

budgets that apply before 2006 and the 60 ton budget that applies in

2006 and after. The legislature eliminated the provision of the budgets

that contained the expiration of the higher budgets and reversion to 44

tons; the legislature did not intend to change the structure of interim

budgets leading to a 60 ton budget in 2006.

EPA Response: Although the statute could have been drafted more

clearly, EPA believes the interpretation of the Attorney General's

Office is reasonable and is entitled to deference. Therefore, EPA

concludes that the statute should be interpreted consistent with the

letter submitted by the Attorney General's Office.

3. No further rulemaking by the AQCC was necessary to eliminate the

expiration of the 60 ton budget. A contrary reading would lead to the

result that the 44 ton budget would apply starting in 1998 when the

legislature clearly did not want this to happen. The legislature made

clear that the 44 ton reversion would only apply for purposes of state

law.

EPA Response: EPA agrees with this interpretation and believes it

is entitled to deference.

4. No further public hearings by the AQCC were necessary following

the Colorado legislature's amendment of the budgets. In addition, no

notice and hearing were required before the legislature itself. The

adoption of the SIP by the AQCC in February 1995 and the amendment of

the SIP by the legislature in May 1995 were steps in the process of

developing a single SIP revision. Nothing in EPA's rules requires

additional hearings at subsequent steps in the state review process. In

addition, the legislative process is open and public and the

legislators are accountable to the electorate.

EPA Response: EPA responds to these comments in Section II.C.,

below.

5. State statutes do not prohibit the submission of the 60 ton

budget for inclusion in the SIP. Other commentors' reading of C.R.S.

section 25-7-105(1)(a)(III) is not consistent with legislative intent.

When the Colorado legislature said the 60 ton budget ``is included in

the SIP only as required by the federal act'', the legislature meant

that the budget is included in the SIP only as required in order for

such emissions budget to apply for the purposes of transportation

conformity. Commentors' reading would negate the 60 ton budget and

result in the application of the 44 ton budget, something the

legislature clearly did not intend. The argument that C.R.S. section

25-7-105.1 prohibits the inclusion of the 60 ton budget in the SIP

because it is not required by the CAA or EPA regulations also fails.

The specific provisions of 25-7-105(1)(a)(III), that indicate the 60

ton budget will apply for federal transportation conformity, control

over the more general provisions of 25-7-105.1.

EPA Response: See EPA's response to comment II.A.2 above. In

addition, EPA believes the interpretation of the Attorney General's

Office is entitled to deference on this question of State law.

C. August 5, 1997 Notice: Procedural Issues. Comments on the

October 3, 1996 notice of proposed rulemaking raised concerns about the

process the State followed in adopting the PM10 budget. EPA sought

additional comment on the question whether the State met the CAA's

notice and public hearing requirements in adopting the PM10 budget. The

following numbered paragraphs contain summaries of the comments

received on the August 5, 1997 notice of proposed rulemaking that are

related to the notice and public hearing issue. EPA's response follows

the last comment summary related to this issue.

1. Hearings held by the AQCC were adequate to satisfy the CAA's

notice and hearing requirements. The hearings before the AQCC and the

subsequent action by the General Assembly should be viewed as a single

process that led to the adoption of the PM10 budgets SIP. There was no

requirement to hold additional hearings before the General Assembly.

The General Assembly was well aware there were parties opposed to the

adoption of the 60 tons-per-day emission budget.

2. The legislative process is open and public and the legislators

are

[[Page 15299]]

accountable to the electorate. The General Assembly provided an

opportunity for public input through a public hearing before a

committee of reference and public debate on the floor of each house.

Environmental groups were actively involved in the debate. In addition,

the public was on notice that the PM10 budgets SIP would be subject to

review by the legislature as provided by section 25-7-133(1), C.R.S.

Therefore, the legislative session itself complied with the notice and

hearing requirements for adoption of the SIP.

3. There was no need for the AQCC to hold a public hearing to

confirm actions taken by the General Assembly.

4. The adequacy of the legislative process with regard to

satisfying the public hearing requirement of section 110 of the CAA and

40 CFR 51.102 is irrelevant. The legislature, when it passed S.B. 95-

110, left discretion with the AQCC to determine the appropriate budget

to submit to EPA. (EPA describes and responds to this comment on this

issue in Sections II. A. and B., above, and will not respond further in

this section.)

5. If EPA decides that the legislature mandated the PM10 budget as

submitted, the legislature did not satisfy the requirements of 40 CFR

51.102 for notice and hearing. In addition, notice and hearing granted

by the AQCC did not satisfy the requirement for notice and hearing

before the legislature.

EPA Response: It has been particularly difficult for EPA to reach a

decision on this issue. EPA takes very seriously the CAA's notice and

public hearing requirements and believes that legitimate questions have

been raised regarding the process the State followed in adopting the

PM10 budget SIP. On balance, however, EPA agrees with the commentors

who asserted that notice and public hearing before the AQCC in February

1995 satisfied the notice and hearing requirements of the CAA and EPA's

regulations. 3 Although the General Assembly reached a

different result than the AQCC, relevant issues regarding the

appropriate size and applicability of the PM10 budgets were aired in

the hearing before the AQCC, and the budgets the General Assembly

ultimately adopted appear to be a logical outgrowth of the hearing

before the AQCC. As noted by one of the commentors, following the

AQCC's February 1995 hearing, the AQCC could have adopted the same

budgets the General Assembly ultimately adopted. Therefore, EPA

concludes that the budget established in the SIP was the result of

adequate notice and hearing.

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\3\ These notice and public hearing requirements can be found in

section 110(a)(2) of the CAA, 42 U.S.C. section 7410(a)(2), and 40

CFR 51.102.

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In finding that notice and public hearing were adequate in this

case, EPA wants to make two points. First, EPA is finding that the

process the State followed satisfied the minimum requirements for

notice and public hearing for purposes of Clean Air Act requirements

and EPA regulations; EPA is not making a finding that the State process

was ideal or should necessarily serve as a model for future actions.

Second, EPA wants to make it clear that legislative amendment of AQCC

rulemaking may not always satisfy the CAA's notice and hearing

requirements. EPA believes the legislative action must bear some

logical relationship to the notice and public hearing previously

concluded before the rulemaking agency, or the notice and public

hearing requirement must be satisfied by the legislature itself or by

subsequent administrative action.

As a prudential matter, EPA would recommend that the State take

steps to optimize public participation so that this type of issue does

not arise in the future. For example, although more than one commentor

suggested the General Assembly was aware of opposition to the 60 ton

budget, none of the commentors indicated whether the General Assembly

or relevant committees thereof actually considered the testimony and

evidence presented to the AQCC; EPA believes it would be prudent to

insure that they do so in the future.

EPA does not agree with those commentors who assert that the

legislative action standing alone met EPA's notice and public hearing

requirements. EPA's regulations are quite specific in their

requirements. Among other things, 30 days prior notice is required. See

40 CFR 51.102. No commentor has suggested that the legislature or one

of its committees complied with this requirement. Also, EPA does not

agree with the commentor who asserts that C.R.S. section 25-7-133(1)

satisfied the CAA's notice requirements, in particular since prior to

the General Assembly's adoption of the PM10 budget SIP, this statute

only provided for the General Assembly to accept or reject a SIP

revision adopted by the AQCC, rather than alter the budget SIP as was

done in this case.

Because EPA concludes that the CAA's notice and hearing

requirements were met in this case, EPA agrees with the commentors who

asserted there was no need for the AQCC to hold an additional hearing

after the General Assembly had acted. However, it is conceivable that

further notice and hearing before the AQCC would have been one way for

the State to satisfy EPA's notice and public hearing requirements if

the February 1995 AQCC hearing had not been sufficient for this

purpose. Another way would have been for the General Assembly itself to

comply with EPA's notice and hearing requirements.

Regarding one commentor's assertion that notice and hearing

requirements were met because environmental groups were actively

involved in the debate regarding the PM10 budgets SIP within the

General Assembly, EPA was unable to substantiate this claim through any

materials submitted by commentors or through independent research.

However, EPA's research revealed that several other parties, including

the AQCC's hearing officer for this SIP, did provide testimony before

the Legislative Council and/or a committee of reference.

D. August 5, 1997 Notice: Substantive Issues. EPA received comments

on its October 3, 1996 notice of proposed rulemaking that raised

concerns regarding the adequacy of the emissions budgets. Based on

these comments, EPA concluded that it needed additional input from

commentors in order to make an informed decision. Thus, in its August

5, 1997 notice, EPA sought additional comment regarding the following

two issues: (1) Whether it was appropriate for the budget SIP to

include a single NOX budget from the 1995 attainment

demonstration of 119.4 tons per day when the maintenance demonstration

NOX emissions inventory was 102.7 tons per day, and (2)

whether potential growth in non-mobile sources was adequately

considered in setting the emissions budgets for years beyond the PM10

SIP attainment and maintenance years. The numbered paragraphs below

contain summaries of the comments received on these issues. For each

issue, EPA's response follows the last comment summary for the

particular issue. EPA has noted where the comment summary includes

comments on the October 3, 1996 notice.

Issue 1: Whether it was appropriate for the budget SIP to include a

single NOX budget of 119.4 tons per day when the maintenance

demonstration NOX emissions inventory was 102.7 tons per

day.

Comment Summaries

1. EPA's analysis of this issue in its August 5, 1997 notice was

correct. The NOX emissions budget of 119.4 tons per day is

consistent with the available safety margin, and therefore need not

conform to the inventory in the maintenance demonstration.

[[Page 15300]]

2. The analysis of the 60 ton PM10 budget assumed NOX

emissions of 119.4 tons per day. This analysis showed that the area

would continue to attain the standard with these emissions values.

Thus, the maintenance year emissions of NOX are irrelevant.

3. Under EPA's conformity rule, projections of emissions in an

attainment SIP beyond the attainment year are not considered emissions

budgets unless the SIP explicitly states such an intent. The SIP states

no such intent.

4. EPA should consider the fact that the Denver area has not

violated the PM10 standard in nearly five years and the highest

recorded value in 1996 was well below the standard. Also, EPA's

promulgation of a new standard for PM10 may soon render these budget

and conformity issues moot.

5. Contrary to EPA's analysis in its August 5, 1997 notice, the

NOX mobile source emissions budget is based on motor vehicle

emission estimates in the Denver PM10 SIP, and not a margin of safety.

The AQCC did not adopt a margin of safety analysis in the SIP which is

why the analysis was not submitted by the State as part of the SIP

submission. The NOX budget submitted by the State offers no

basis for the rationale offered by EPA in its August 5, 1997 notice.

The conformity rule provides that transportation agencies may not infer

additions to budgets not explicitly intended by the SIP; the same rule

must apply to EPA. The SIP must quantify the amount by which motor

vehicle emissions could be higher while still allowing a demonstration

of maintenance and must specifically indicate that the excess emissions

are to be allocated to the MPO for transportation conformity purposes.

The SIP did not meet either of these requirements. In fact, in the

maintenance year there are no excess emissions to allocate. The RAQC

staff's analysis, which EPA cites in its August 5, 1997 notice, does

not consider emissions from all sources and does not require that

emissions be distributed to all grid receptors. The maintenance

demonstration approved by the AQCC and submitted as part of the PM10

SIP that EPA has approved shows that motor vehicle NOX

emissions must be no higher than 102.7 tons in order to demonstrate

maintenance. The RAQC staff's analysis shows that more emissions could

be added in portions of the Metro area not yet developed, but it

provides no basis for concluding that more emissions can safely be

added where vehicle travel is currently occurring. Since the SIP does

not restrict emissions to the undeveloped portions of the Metro area,

there is no basis to conclude there are excess emissions to be

allocated and there is no basis to rely on the RAQC staff's analysis.

Adding 17 additional tons of NOX in the developed portions

of the Metro area in the maintenance year would cause estimated

concentrations to exceed the NAAQS. In addition, the RAQC staff's

analysis was never officially adopted by anyone. We reiterate comments

made on the October 3, 1996 proposal that EPA approve the 119.4 ton per

day budget as the applicable budget only for analyses performed up to

the attainment year, and that EPA clarify that the applicable budget

after the attainment year is the NOX estimate contained in

the maintenance demonstration portion of the approved SIP.

This same commentor also indicated in comments on EPA's October 3,

1996 notice of proposed rulemaking that the use of a 119.4 tons per day

NOX emission budget for years after the attainment year

would not be consistent with the obligation to set an emission budget

consistent with the demonstration of maintenance. In those comments,

the commentor cited to the preamble statement in EPA's November 24,

1993 conformity rule that, ``[i]n all situations, the emissions budget

in the SIP must be consistent with the attainment or maintenance

demonstration * * *'' Because the 119.4 ton budget is not consistent

with the 102.7 ton inventory in the maintenance year, the commentor

argued that the appropriate NOX budget would be 119.4 tons

per day NOX up to the attainment year, but would be 102.7

tons per day NOX beyond the attainment year. EPA Response:

In its August 5, 1997 supplemental notice, EPA proposed approval of the

PM10 and NOX budgets for Denver based in part on the safety

margin analysis conducted by the RAQC. This analysis sought to

demonstrate that mobile source emissions in the Denver modeling region

could be as high as 221 tons per day of PM10 before violations of the

NAAQS would occur. After reviewing all of the comments and carefully

considering the requirements of the conformity rule and the Act, EPA

has determined that it can no longer endorse the RAQC's suggested

approach for defining a safety margin.

The conformity rule, as amended on August 15, 1997, defines safety

margin as the amount by which the total projected emissions from all

sources of a given pollutant are less than the total emissions that

would satisfy the applicable requirement for reasonable further

progress, attainment or maintenance of the relevant air quality

standard. For example, many maintenance plans include maintenance year

emission inventories which are lower than the attainment year

inventory. The difference between these two levels of emissions could

be considered a margin of safety. Some attainment SIPs are submitted

with modeled attainment values which are somewhat below the standard;

the difference in emissions between the SIP level and the level that

would just provide for attainment of the standard could be considered a

safety margin.

However, the RAQC's analysis is based on maximizing emissions in

all grids in the modeling domain, and as such is more of a ``carrying

capacity'' analysis. It bears no relation to the attainment or

maintenance year emission inventory; emissions in all portions of the

modeling domain were increased to levels equivalent to downtown Denver,

including remote rural regions, even though activity levels in the

remote grids in the attainment or maintenance year were not high enough

to create such emissions levels. The RAQC's approach to establishing a

safety margin would appear to conflict with the requirements of section

176(c)(2)(A) of the CAA.

It would have been more appropriate to calculate a safety margin

for Denver by determining the difference in emissions between the

modeled 1995 attainment value (147.7 ug/m3) and the standard of 150 ug/

m3, by proportionally increasing the 1995 inventory used in the

modeling until the standard had been reached. A safety margin

calculated in this way would likely only amount to a few tons per day.

However, the RAQC did not calculate its safety margin this way, and EPA

has decided it cannot rely on the RAQC's analysis for purposes of this

action, nor is EPA generally endorsing this approach for the

establishment of safety margins in other nonattainment or maintenance

areas. Thus, EPA is not relying on the RAQC's safety margin analysis to

justify approval of the 119.4 tons per day NOX budget.

In addition, EPA finds unconvincing the argument that 1998

projections of NOX emissions would not be a budget for

conformity purposes unless the SIP states explicitly states such an

intent. The conformity rule is clear that approved attainment and

maintenance demonstrations and any required milestone demonstrations

establish budgets which must be used for conformity until superseded by

subsequent approved SIPs for those same years. In this case, the PM10

SIP's 1998 maintenance demonstration was

[[Page 15301]]

required by section 189(c) of the CAA; i.e., it was a required

milestone. EPA notes that the State did establish a 1998 PM10 budget,

and that 1998 PM10 budgets have been established for other PM10

nonattainment areas within the State of Colorado. Also, EPA does not

agree with the approach of establishing a budget for one precursor of

PM10 for any given year, but not all of them. Since the PM10 and

NOX inventories work in tandem as part of the attainment and

maintenance demonstrations in Denver, it does not make technical sense

to regulate one pollutant through conformity but not the other. The

conformity rule is clear that these inventories are to be treated as

budgets for purposes of conformity; a state may not evade this

requirement by merely declaring an intent that a required attainment,

maintenance or milestone inventory for a pollutant or pollutant

precursor is not to be considered a budget. The conformity rule

language cited by the commentors in asserting that the 1998

NOX budget is not to serve as a budget refers to optional

projections of emissions in SIPs that are not otherwise required by the

Act or EPA SIP policy. In this case, both PM10 and NOX motor

vehicle emissions inventories were required as part of the maintenance/

milestone demonstration in the PM10 SIP.

However, EPA notes that the NOX budget of 119.4 tons per

day from the 1995 attainment demonstration was used in the modeling

analysis which the APCD used in adopting the 60 ton PM10 budget. EPA

also notes that projected NOX emissions from the

transportation plan and TIP (not to exceed the adopted budget of 119.4

tons per day) are required to be used in the dispersion modeling

conducted for each conformity determination. Therefore, since the

budgets and their associated dispersion modeling requirement will

provide for maintenance of the NAAQS, as discussed in section II. A.

3., above, EPA is also approving the 119.4 tons per day NOX

budget for all future years. EPA views the latest submission which

relied on this analysis as setting the valid budget for this period for

transportation conformity purposes, which is today approved into the

SIP.

Finally, as noted by one commentor, EPA promulgated a revised PM10

NAAQS on July 18, 1997. (See 62 FR 38652.) Specifically, the form of

the NAAQS was revised in a way that makes the standard less stringent

overall. As a result of the promulgation of the new PM10 NAAQS, EPA may

in the near future revoke the old PM10 NAAQS for Denver. However, EPA

has not yet decided whether conformity requirements will continue to

apply to areas for which the old PM10 NAAQS has been revoked and for

which no new nonattainment designation has been made. Furthermore, the

old PM10 NAAQS has not yet been revoked for Denver. Therefore, the

budgets are not moot, and the mere possibility that the new NAAQS may

render the budgets moot is not relevant to EPA's decision to approve

the budgets. Also, the fact that the area has been attaining the PM10

NAAQS, while providing an extra measure of comfort regarding the

attainment and maintenance/milestone demonstrations in the PM10 SIP,

does not by itself provide an adequate technical basis for EPA to

approve the budgets.

Issue 2: Whether potential growth in non-mobile sources was

adequately considered in setting the emissions budgets for years beyond

the PM10 SIP attainment and maintenance years.

Comment Summaries

1. As EPA noted in its August 5, 1997 notice, the conformity rule

does not require consideration of growth in non-mobile sources each

time a conformity determination is made. EPA's analysis in its August

5, 1997 notice is consistent with the application of conformity

requirements in nonattainment areas throughout the country. Further,

the conformity rule does not require the mobile source sector to offset

projected growth in emissions from non-mobile sources.

2. No growth in non-mobile sources is expected over the next 20

years. Thus, growth in non-mobile sources is a non-issue. This

commentor submitted data to support this assertion.

EPA Response: In addition to the comments received above, the

preamble to EPA's August 15, 1997 amended conformity rule is relevant

to this question and EPA has considered the preamble language in

addressing this issue.

In conducting the modeling that led to the establishment of the 60

ton budget, APCD held all non-mobile sources (and mobile source

NOX) constant at 1995 levels. There was concern that the 60

ton budget would not provide for attainment if non-mobile source

emissions were to increase in future years.

Normally, EPA would not approve a budget that had been established

without considering growth in all source categories. The Act and EPA

policy are clear that attainment and maintenance SIPs must consider

growth in all sources in demonstrating attainment or maintenance of the

NAAQS, and the conformity rule's budget test relies on the fact that

SIP budgets do consider growth in all sources to ensure that

transportation plans, programs and projects will not cause or

contribute to violations of the NAAQS. The preamble to EPA's August 15,

1997 conformity rule establishes that growth in non-mobile sources must

be considered in setting motor vehicle emission budgets for years

beyond the attainment or maintenance demonstration (62 FR 43787-

43788).4

---------------------------------------------------------------------------

\4\ A number of commentors indicated that the conformity rule

does not require consideration of growth in non-mobile sources for

conformity determinations. This is accurate but should be

distinguished from the initial setting of motor vehicle emission

budgets in SIPs. The preamble to EPA's August 15, 1997 conformity

rule is clear that growth in non-mobile sources must be considered

in setting ``out-year'' budgets. 62 FR 43787-43788.

---------------------------------------------------------------------------

However, in response to EPA's request for public comment, the RAQC

submitted documentation indicating there will be no growth in non-

mobile sources at any time in the near future. The RAQC has been

working since 1995 on development of a long-range air quality plan

known as the Blueprint for Clean Air for PM10 and two other pollutants.

As part of this plan, long-term projections of emissions from all

source categories have been developed by the RAQC and the State Air

Pollution Control Division. The information submitted to the docket for

this rulemaking by the RAQC demonstrates that non-mobile sources will

remain below 1995 levels through at least the year 2020, and will be

approximately 5 percent below 1995 levels in 2020.

Since it does not appear that there will be any growth in non-

mobile sources in the Denver area over the time period for which the

budgets were analyzed, EPA is approving the MVEB even though growth in

these sources was not assessed for purposes of developing and adopting

the MVEB.

In its August 5, 1997 supplemental notice, EPA proposed to approve

the budgets in part based on a safety margin analysis prepared by the

RAQC. In its analysis, EPA noted that the calculated safety margin of

221 tons per day of PM10 in 2015 was developed assuming 2015 levels of

non-mobile source emissions; i.e., growth, or lack thereof, in non-

mobile source emissions had been factored into the calculation of the

so-called safety margin. As described above, EPA no longer believes the

RAQC characterization of safety margin is consistent with the CAA or

the conformity rules. Therefore, EPA is not relying on the RAQC safety

margin analysis in approving the budgets.

[[Page 15302]]

III. Final Action

EPA is approving the Denver PM10 and NOX mobile source

emissions budget SIP revisions submitted by the Governor of Colorado on

July 18, 1995 and April 22, 1996 respectively as revisions to the

Colorado SIP. The revisions were submitted in order that they could be

used to assess the conformity of transportation plans, transportation

improvement programs and, where appropriate, federally funded projects

for applicable periods prescribed under conformity requirements within

the Denver PM10 nonattainment area.

The current and future year mobile source emissions budgets that

comprise part of these SIP revisions are as follows:

PM10: 54 tons per day, for analysis years 1998-2005

60 tons per day, for analysis years 2006 and beyond

NOX: 119.4 tons per day, for analysis years 1998 and

beyond

These budgets are applicable to the PM10 SIP modeling domain.

For these pollutants, these budgets supersede any prior budgets for

the Denver PM10 nonattainment area for the same time frames. The

metropolitan planning organization for the Denver PM10 nonattainment

area will have to demonstrate conformity to these budgets within 18

months of EPA's approval of these budget SIPs, in accordance with 40

CFR 93.104(e)(3).

It should be noted that, in addition to the budgets themselves, the

SIP revisions that EPA is approving today contain other provisions that

must be followed in making transportation conformity determinations

within the Denver PM10 nonattainment area. These provisions include,

but are not necessarily limited to, descriptions of relevant inventory

categories, definitions of applicability, and requirements related to

dispersion modeling.

IV. Administrative Requirements

A. Executive Order 12866

The Office of Management and Budget (OMB) has exempted this

regulatory action from E.O. 12866 review.

B. Regulatory Flexibility Act

Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA

must prepare a regulatory flexibility analysis assessing the impact of

any proposed or final rule on small entities. 5 U.S.C. 603 and 604.

Alternatively, EPA may certify that the rule will not have a

significant impact on a substantial number of small entities. Small

entities include small businesses, small not-for-profit enterprises,

and government entities with jurisdiction over populations of less than

50,000.

SIP approvals under section 110 and subchapter I, part D of the

Clean Air Act do not create any new requirements but simply approve

requirements that the State is already imposing. Therefore, because the

Federal SIP approval does not impose any new requirements, the

Administrator certifies that it does not have a significant impact on

any small entities affected. Moreover, due to the nature of the

Federal-State relationship under the CAA, preparation of a flexibility

analysis would constitute Federal inquiry into the economic

reasonableness of state action. The Clean Air Act forbids EPA to base

its actions concerning SIPs on such grounds. Union Electric Co. v. U.S.

EPA, 427 U.S. 246, 255-66 (1976); 42 U.S.C. 7410(a)(2).

C. Unfunded Mandates

Under Section 202 of the Unfunded Mandates Reform Act of 1995

(``Unfunded Mandates Act''), signed into law on March 22, 1995, EPA

must prepare a budgetary impact statement to accompany any proposed or

final rule that includes a Federal mandate that may result in estimated

costs to State, local, or tribal governments in the aggregate; or to

private sector, of $100 million or more. Under Section 205, EPA must

select the most cost-effective and least burdensome alternative that

achieves the objectives of the rule and is consistent with statutory

requirements. Section 203 requires EPA to establish a plan for

informing and advising any small governments that may be significantly

or uniquely impacted by the rule.

EPA has determined that the approval action promulgated does not

include a Federal mandate that may result in estimated costs of $100

million or more to either State, local, or tribal governments in the

aggregate, or to the private sector. This Federal action approves pre-

existing requirements under State or local law, and imposes no new

requirements. Accordingly, no additional costs to State, local, or

tribal governments, or to the private sector, result from this action.

D. Submission to Congress and the General Accounting Office

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the

Small Business Regulatory Enforcement Act of 1996, generally provides

that before a rule may take effect, the agency promulgating the rule

must submit a rule report, which includes a copy of the rule, to each

House of Congress and to the Comptroller General of the United States.

EPA will submit a report containing this rule and other required

information to the U.S. Senate, the U.S. House of Representatives, and

the Comptroller General of the United States prior to publication of

the rule in the Federal Register. This rule is not a ``major rule'' as

defined by 5 U.S.C. 804(2).

E. Petitions for Judicial Review

Under section 307(b)(1) of the Clean Air Act, petitions for

judicial review of this action must be filed in the United States Court

of Appeals for the appropriate circuit by June 1, 1998. Filing a

petition for reconsideration by the Administrator of this final rule

does not affect the finality of this rule for the purposes of judicial

review nor does it extend the time within which a petition for judicial

review may be filed, and shall not postpone the effectiveness of such

rule or action. This action may not be challenged later in proceedings

to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Hydrocarbons,

Incorporation by reference, Intergovernmental relations, Nitrogen

dioxide, Particulate matter, Reporting and recordkeeping requirements,

Sulfur oxides, Volatile organic compounds.

Dated: February 26, 1998.

William P. Yellowtail,

Regional Administrator, Region VIII.

40 CFR part 52 is amended as follows:

PART 52--[AMENDED]

1. The authority citation for part 52 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

Subpart G--Colorado

2. Section 52.320 is amended by adding paragraphs (c)(84) to read

as follows:

Sec. 52.320 Identification of plan.

* * * * *

(c) * * *

(84) The Governor of Colorado submitted the Denver PM10 mobile

source emissions budget State Implementation Plan (SIP) with a letter

dated July 18, 1995. The Governor submitted the Denver NOX

mobile source emissions budget State Implementation Plan (SIP) with a

letter dated April 22, 1996. The PM10 and NOX mobile source

emissions budgets and other provisions in these SIP

[[Page 15303]]

submittals are used to assess conformity of transportation plans,

transportation improvement programs, and transportation projects.

(i) Incorporation by reference.

(A) Colorado Air Quality Control Commission, ``Ambient Air Quality

Standards'' regulation 5CCR 1001-14, Section A.1. Budgets for the

Denver Nonattainment Area (Modeling Domain) PM10, Sections A.2. and

A.3., and Sections B and C, adopted on February 16, 1995, effective

April 30, 1995, as amended by the Colorado General Assembly through

enactment of Colorado Senate Bill 95-110, which Bill was enacted on May

5, 1995 and signed by the Governor of Colorado on May 31, 1995. (See

paragraph (c)(84)(i)(B) of this section).

(B) Colo. Rev. Stat. section 25-7-105(1)(a)(III), enacted by the

Colorado General Assembly on May 5, 1995 as part of Colorado Senate

Bill 95-110 and signed by the Governor of Colorado on May 31, 1995.

(C) Colorado Air Quality Control Commission ``Ambient Air Quality

Standards'' regulation 5CCR 1001-14, Section A.1. Budgets for the

Denver Nonattainment Area (Modeling Domain) Nitrogen Oxides, as adopted

June 15, 1995, effective August 30, 1995.

[FR Doc. 98-8214 Filed 3-30-98; 8:45 am]

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