FEDERAL LAND MANAGERS’

AIR QUALITY RELATED VALUES

WORKGROUP (FLAG)

RESPONSE TO PUBLIC COMMENTS

ON DRAFT PHASE I REPORT

U.S. FOREST SERVICE – AIR QUALITY PROGRAM

NATIONAL PARK SERVICE – AIR RESOURCES DIVISION

U.S. FISH AND WILDLIFE SERVICE – AIR QUALITY BRANCH

Table of Contents

A. INTRODUCTION ....................................................................................................................1

B. RESPONSE TO POLICY COMMENTS ..................................................................................3

C. RESPONSE TO VISIBILITY COMMENTS .........................................................................15

D. RESPONSE TO OZONE COMMENTS .................................................................................31

E. RESPONSE TO DEPOSITION COMMENTS .......................................................................42

APPENDIX

SUMMARY OF PUBLIC COMMENTS ON DRAFT FLAG PHASE I REPORT
A. INTRODUCTION

The Federal Land Managers' Air Quality Related Values Work Group (FLAG) was formed to

develop a more consistent approach for the Federal Land Managers (FLMs) to evaluate air

pollution effects on their resources. Of particular importance is the New Source Review (NSR)

program, especially in the review of Prevention of Significant Deterioration (PSD) of air quality

permit applications. The goals of FLAG have been to provide consistent policies and processes

both for identifying air quality related values (AQRVs) and for evaluating the effects of air

pollution on AQRVs, primarily those in Federal Class I air quality areas, but in some instances,

in Class II areas. FLAG members include representatives from the three FLMs that administer

the nation's Federal Class I areas: the U.S. Department of Agriculture Forest Service

(USDA/FS), the U.S. Department of the Interior National Park Service (NPS), and the U.S. Fish

and Wildlife Service (FWS).

This Response to Public Comments on Phase I Report accompanies the FLAG Phase I report.

The FLAG Phase I report describes the work accomplished in Phase I of the FLAG effort. That

work includes identifying policies and processes common to the FLMs and developing new

policies and processes using readily available information. The Phase I report provides State

permitting authorities and potential permit applicants a consistent and predictable process for

assessing the impacts of new and existing sources on AQRVs, including a process to identify

those AQRVs and potential adverse impacts. The report also discusses non-new source review

considerations and managing emissions in Federal areas.

The FLAG Phase I report also focuses on the effects of the air pollutants that could affect the

health of resources in Class I areas, primarily pollutants such as ozone, particulate matter,

nitrogen dioxide, sulfur dioxide, nitrates, and sulfates. FLAG concentrated on three effects

issues: (1) visibility impairment; (2) terrestrial effects of ozone; and (3) aquatic and terrestrial

effects of wet and dry pollutant deposition. FLAG formed a subgroup to address each of these

issues. The Phase I report consolidates the results of each effects subgroup, as well as the policy

subgroup. The chapters prepared by these subgroups contain issue-specific technical and policy

analyses, recommendations for evaluating AQRVs, and guidelines for completing and evaluating

NSR permit applications. These recommendations and guidelines are intended for use by the

FLMs, permitting authorities, NSR permit applicants, and other interested parties. The report

also includes background information on the roles and responsibilities of the FLMs under the

NSR program.

In Phase I, FLAG findings and technical recommendations underwent scientific peer review, as

well as review by agency decisionmakers, such as Class I area Park Superintendents, Refuge

Managers, and Forest Supervisors. FLAG products have also undergone public review and

comment. A “notice of availability” of the draft FLAG report was published in the Federal

Register, and the FLMs conducted a public meeting to discuss the draft FLAG report and

provided a 90-day public comment period.

During the public comment period, the FLMs received many comments. The FLMs considered

all comments received and revised the Phase I report accordingly. This "Response to Public

Comments" document discusses the public comments and provides the rationale for accepting or
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rejecting the comment. Many of the comments addressed common themes. Therefore, to the

extent possible, the FLMs responded to common issues raised, rather than addressing each

comment individually. The FLMs' responses to specific Policy, Visibility, Ozone, and

Deposition issues follow in subsequent sections of this report. Please note that although the

comment/response format for each subgroup is somewhat different, each subgroup did consider

all comments. The Appendix includes a list of all public commenters (in no particular order), and

a brief summary of issues raised in their comments. Finally, the FLMs appreciate the interest

shown in the FLAG process. The FLAG Phase I report benefited from the public review process

and is an improved report as a result of public comments received.
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B. RESPONSE TO POLICY COMMENTS

This section identifies, and responds to, “recurring themes” found throughout the public

comments on the policy sections of the draft FLAG Phase I report. Approximately 40

commenters addressed policy issues within the draft FLAG report. The following 11 repeated

comments have been prioritized according to the number of responses per issue. Following the

section dealing with FLM responses to the 11 recurring themes is a separate section dealing with

15 individual/specific comments.

Major Recurring Themes and FLM Responses

1. Comment: Several commenters stated that by asking permit applicants to perform AQRV

impact analyses, FLAG exceeds the FLM's statutory authority by shifting the burden of proof

from the FLM to the permit applicant when the PSD Class I increment is not violated. The

commenters assert that when the increment is not violated, it is the FLM's responsibility to

perform all AQRV analyses.

Response: The commenters' assertion that a permit applicant is not required to perform an

AQRV impact analysis unless the proposed source would cause or contribute to a Class I

increment violation is incorrect. The applicant must perform the AQRV analysis as part of a

complete application, regardless of the increment status. The legislative history and current EPA

regulations and guidance support the FLMs' position that it is the applicant's responsibility to

provide the information necessary to allow the FLM to make an informed decision about

potential deterioration of air quality in a Class I area and potential adverse impacts on AQRVs.

(See EPA’s New Source Review Workshop Manual (October 1990), Guideline on Air Quality

Models (Revised) (EPA-450/2-78-02R (Revised 1996)), Interagency Workgroup on Air Quality

Modeling (IWAQM) Phase 1 Report: Interim Recommendation for Modeling Long Range

Transport and Impacts on Regional Visibility (EPA-454/R-93-015, April 1993). For example,

EPA’s New Source Review Workshop Manual, which has been widely disseminated to permitting

agencies and relied on in permit appeals (See Inter-Power of New York, Inc., 5 E.A.D. 130, March

16, 1994), states on page E.12, “When a proposed major source’s or major modification’s modeled

emissions may affect a Class I area, the applicant analyzes the source’s anticipated impact on

visibility and provides the information needed to determine its effect on the area’s other

AQRVs.” (emphasis added). Other references throughout Chapter E also refer to the applicant’s

AQRV analysis (e.g., page E.20 states that EPA recommends that the State not consider a permit

application complete “until the FLM certifies that it is “complete” in the sense that it contains

adequate information to assess adverse impacts on AQRVs.”)

A September 10, 1991, EPA Memorandum from the Director, Air Quality Management Division,

states that a source is required to perform an AQRV analysis even if it has insignificant impacts on

Class I increments. In this policy memorandum, EPA makes clear that the increment test is not to

be used for determining whether a source would conduct an AQRV analysis or have an adverse

impact on a Class I area. Rather, the FLM determines the need for an applicant to perform a full

assessment of impacts on AQRVs based on an analysis of the proposed source’s (and other

cumulative) potential impacts on a value for that particular Class I area. This analysis is

independent of the inquiry into whether a proposed source would have a significant impact on any
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applicable Class I increment. In addition, the visibility protection provisions require FLM

notification of a proposed source that may affect visibility in a Class I area and that notification

“must include an analysis of the anticipated impacts on visibility.” (See 40 CFR 51.307(a)(1)).

As stated in the FLAG report, the FLMs believe that those wishing to add pollution to the air

should bear the burden of estimating the potential, resulting concentrations of air pollutants that

affect AQRVs, both from the individual source and the cumulative impacts. FLMs view this

analysis as just one part of the permit application. It is the permit applicant's responsibility to

provide BACT and increment/NAAQS modeling analyses to enable the permitting authority to

determine whether the proposed source complies with these requirements. Similarly, the permit

applicant should provide analyses that project fine particle concentrations and deposition

associated with sulfur and nitrogen oxide-related emissions from the proposed source or

modification. To assist the permit applicant in performing any necessary AQRV-related

analyses, the FLMs will provide all available information about any AQRV for that particular

federal Class I area that may be adversely affected by emissions from the proposed source and

recommend methods the applicant should use to analyze the potential effects on such AQRV(s).

Several commenters suggested that, because it is the FLM's responsibility to make an adverse

impact demonstration, it is also the FLM’s responsibility to perform any air quality analyses

needed to assess AQRV impacts. The FLMs agree that when the Class I increments are not

violated, it is the FLM's responsibility to “demonstrate” to the permitting authority that a proposed

source would cause or contribute to adverse impacts on AQRVs. However, this demonstration is

to be based on the applicant's analyses of changes in relevant air quality parameters (e.g., visibility

extinction, acid deposition), and these analyses are required as part of a complete application. The

FLM then considers the results of these analyses and any other relevant information in the adverse

impact demonstration. If the FLM determines adverse impacts would occur, the FLM would bear

the burden of demonstrating such to the permitting authority. If the permitting authority is

“satisfied” with the FLM’s demonstration, no permit will be issued without mitigation (e.g.,

emission offsets). FLAG guidance reflects the respective responsibilities of the FLMs, permit

applicants, and permitting authority, and does not shift any burden from one party to another.

Furthermore, Section 165 of the Clean Air Act (CAA) sets forth no statutory “burden” relating to

whom should bear the costs for studying the impacts of a proposed facility on Class I areas.

Therefore, since there is no statutory burden, the question is not whether the burden is being

shifted, but rather whether the public or the PSD applicant should pay for analyses that will be

used in private ventures. As the statute is silent on this matter, it is well settled that the agency

charged with implementing a statute is given deference by the courts to its interpretation, so long

as this interpretation is reasonable and not contrary to Congressional intent.

Therefore, the position of the FLMs is, and remains, that the PSD applicant should bear the costs

of analyses which will ascertain the impact of the applicant’s proposed project on natural

resources under the control and jurisdiction of the FLMs, even when this information is used to

satisfy the FLMs’ affirmative duty to protect Class I areas. Further, as noted above, this position

is consistent with long standing EPA practices in its BACT and other programs, and is grounded

in law and common sense.
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2. Comment: Several commenters state that Clean Air Act section 165(d), 42 U.S.C. § 7475(d),

only requires an analysis of an individual permit applicant’s impact, as opposed to an analysis of

the cumulative impacts of other operating and proposed sources, on Class I areas.

Response: This alleged limited review requirement calling for only an analysis of an individual

permit applicant's impact is not present in Section 165. Additionally, to only analyze the

anticipated impacts of one individual source, and then to ignore the cumulative impacts of other

sources on these same resources, defies logic and would trivialize Section 165’s intent. The

most logical and most scientifically sound manner in which to assess the real impacts of a

proposed pollution source is to consider it as it relates to, and may add to, already present

activities, and those permitted polluting activities that are pending but may not already be in

operation. To fulfill the affirmative obligation to protect Class I values in PSD applications, as

mandated by section 165(d), the FLM must consider a proposed new source in the context of

existing and known impacts. Furthermore, Section 165(d)(2)(C)(i) makes clear the need to

consider cumulative impacts in making an adverse impact determination. This section states in

part, "...where the Federal official...or the Federal Land Manager ...files a notice alleging that

emissions from a proposed major emitting facility may cause or contribute to a change in the

air quality..." (emphasis added)

3. Comment: The FLM should clarify which “very large" sources located greater than 100 km

are subject to FLM review.

Response: The FLMs retained the “very large sources” language as it was in the draft FLAG

report because that language is consistent with EPA guidance. However, the FLMs added the

following clarifying language to better define which sources are of FLM concern (see bottom of

page 9 and top of page 10 of the final FLAG report):

"Given the multitude of possible size/distance combinations, the FLMs can not precisely

define in advance what constitutes a "very large source" located more than 100 km away

that may impact a particular Class I area. Therefore, the FLM and permitting authority

should work together to determine which PSD applications the FLM is to be made aware

of in excess of 100 km. The FLM and permitting authority should make this

determination on a case-by-case basis, considering such factors as:

• Current conditions of sensitive AQRVs;

• Magnitude of emissions;

• Distance from the Class I area;

• Potential for source growth in an area/region;

• Existing/prevailing meteorological conditions;

• Cumulative effects of several sources to AQRVs.

Additionally, such dialogue facilitates coordination between permitting authorities and

the FLMs. The significance of the impact to AQRVs is more important than the distance

of the source. Not all PSD permit applications that the FLM is notified of will be

analyzed in-depth by the FLM. FLM notification of a PSD permit application for a
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project located greater than 100 km does not mean that that application will be reviewed

by the FLM in detail. Notification of PSD permit applications in excess of 100 km by the

permitting authority allows the FLM to gauge the level of potential cumulative effects.

As indicated above, the FLM decides which PSD permit applications to review on a caseby-case basis depending on the potential impacts to AQRVs."

4. Comment: Several commenters contend that FLAG is a legislative rule that must comply with

the Administrative Procedures Act and other statutory requirements, including an assessment of

economic consequences of FLAG implementation.

Response: Although the FLMs have an "affirmative responsibility" to protect AQRVs, they have

no permitting authority under the CAA, and they have no authority under the CAA to establish

air quality-related rules or standards. The FLM role consists of considering whether emissions

from a new source may have an adverse impact on AQRVs and providing comments to

permitting authorities (States or EPA). The FLAG report is a guidance document that explains

factors and information the FLMs expect to use when carrying out their consultative role.

Therefore, it is not a legislative rule subject to informal rulemaking procedures under the

Administrative Procedures Act (APA), or any other statutory requirements. Guidance documents

themselves do not create rights and responsibilities under the law, and guidance documents are

not legally binding on outside parties or on the agencies. Instead, guidance documents explain

how the agency believes the law applies to certain regulated activities. As such, it is not binding

on the agency or the public; that is, it represents the agencies' current thinking on the kinds of

information permittees should include in permit applications so the FLMs can assess whether the

proposed emissions cause or contribute to adverse impacts on AQRVs at Class I areas. For the

benefit of the agencies and the public, the FLAG report describes the steps and process that an

agency intends to go through in order to perform its statutory duties.

Although FLAG, as a guidance document, cannot legally bind the participating FLMs, each FLM

recognizes the value of guidance documents in providing consistency and predictability.

Therefore, each FLM will take steps to encourage their employees to conduct their permit

reviews consistent with the process in the FLAG report, recognizing that there is flexibility and

discretion for case-by-case consideration built into the process. Based on our past experiences,

permittees want assurances that the FLMs will act in a certain manner, and that if they (the

permittees) follow certain recommended procedures, the FLMs will be satisfied. Moreover, the

agencies issue guidance to their staffs so that they will apply the CAA and its regulations in a

consistent manner.

Again, the FLAG report is not a rule. Rules are generally defined as agency statements of general

applicability and future effect that the agency intends to have the force and effect of law. As

discussed above, the FLAG report does not purport to do so.

Finally, even if the FLAG report were something more than a guidance document, the FLMs

have complied with the requisite notice and comment procedures required by the APA. The

public received notice that the FLMs intended to develop the FLAG report and had the

opportunity to comment and to discuss the FLAG report with the FLMs.
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5. Comment: Several commenters state that FLAG should not expand FLM review to include

Class II lands. They assert that the FLM role regarding AQRV protection under the CAA is

limited to Class I areas, not impacts to Class II lands.

Response: The FLMs have significant congressional direction other than the Federal Clean Air

Act for protecting lands that they manage. The Property clause of the United States Constitution

delegates the power to Congress to make all needful rules respecting property belonging to the

United States (U.S. Constitution, Article IV, Section 3, c12). For example, this authority has

been delegated to the Secretary of Agriculture and to the Forest Service through the Organic

Administration Act of 1897 (16 U.S.C. 551). This Act directs the Secretary of Agriculture to

“...make provisions against destruction by fire and depredations upon the public forests and

national forests...” The magnitude of air pollution impacts to National Forest System lands can

be classified as a depredation. The Organic Administration Act does not specify that certain

lands should not be considered for protection from air pollution depredations because of their air

quality designation. As such, the Agency should exercise all legal authorities to protect all

National Forest Systems lands from air pollution depredations.

The National Park Service’s Organic Act (16 U.S.C. 1) directs the National Park Service to:

“...conserve the scenery and the natural and historic objects and wildlife therein and to

provide for the enjoyment of the same in such a manner and by such means as will leave

them unimpaired for the enjoyment of future generations.”

This Congressional direction applies to all NPS units, not only those designated as Class I

through the Clean Air Act.

The National Wildlife Refuge Administration Act (16 U.S.C. 668dd(a)(4)(B)) directs the Fish

and Wildlife Service to manage Refuge System lands to:

"...ensure that the biological integrity, diversity, and environmental health of the System

are maintained for the benefit of present and future generations of Americans.”

Again, this Congressional direction applies to the management of all Refuge System lands, not

only those designated as Class I through the Clean Air Act.

The Wilderness Act of 1964 applies to all wilderness lands administered by the Departments of

Interior and Agriculture, not only those lands provided with a certain air quality designation by

the Clean Air Act. It is evident in the language of the Wilderness Act that Congress wanted all

wildernesses to be protected from human-caused influences.

“Section 2. (a) In order to assure that an increasing population, accompanied by

expanding settlement and growing mechanization, does not occupy and modify all areas

within the United States and its possessions, leaving no lands designated for preservation

and protection in their natural condition, it is hereby declared to be the policy of Congress

to secure for the American people of present and future generations the benefits of an

enduring resource of wilderness.”
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“Section 2. (c) An area...which is protected and managed so as to preserve its natural

conditions...”

Air pollution modifies the natural conditions of air quality related values in wilderness.

The Clean Air Act (42 U.S.C. 7401 et. seq.) does not limit federal agencies' responsibilities and

authorities in other statutes such as their respective Organic Acts and the Wilderness Act.

“42 U.SC. 7610 (a) ...this Act shall not be construed as superseding or limiting the

authorities and responsibilities, under any other provision of law, of the Administrator or

any other Federal officer, department or agency.”

The Clean Air Act provides an opportunity for FLMs and members of the public to make

recommendations on major source permitting activities regardless of whether or not the land area

under consideration is designated Class I or Class II. Every new source permitted under the

Prevention of Significant Deterioration sections of the Clean Air Act must demonstrate that it is

installing and operating air pollution control equipment that meets or exceeds a level of control

defined as best available control technology (BACT). BACT is determined on a case-by-case

basis by the permitting agency which must consider economics, energy costs, and environmental

impacts when determining a level of air pollution control to be achieved. FLMs have the

opportunity to provide information to the permitting agency on the environmental impacts of the

proposed facility. If the FLM can make the case that proposed facility will, by itself or in

combination with other sources, cause or contribute to an adverse impact to an air quality related

value on Class II or other federal lands, the permitting agency has the authority to require

additional control equipment to be installed on the proposed facility to mitigate all or part of the

adverse impact.

Given the above direction from Congress on how FLMs should manage and protect federal lands

and the opportunities provided by the Prevention of Significant Deterioration sections of the

Clean Air Act for protecting all federal lands, it is appropriate for FLMs to extend their review to

Class II lands.

In summary, Congress has given FLMs clear direction and authority to protect the lands they

administer other than just through the Clean Air Act. Air pollution has the ability to significantly

impact lands designated either as Class I or Class II through the Clean Air Act. Congress, in the

Clean Air Act, recognized that federal agencies and departments have other statutes to comply

with and specifically stated that the Clean Air Act shall not supersede or limit their authorities

and responsibilities. It would be inconsistent with other federal law if FLMs did not take

advantage of all legal opportunities to prevent air pollution impacts to all the lands they

administer including Class II lands. Therefore, it is proper and appropriate for FLMs to exercise

their respective authorities in protecting Class II lands from air pollution impacts.

6. Comment: Several commenters stated that FLAG should have included more stakeholder

involvement.
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Response: As FLAG was being formed, the FLMs considered establishing a multi-stakeholder

process under the Federal Advisory Committee Act. However, the FLMs decided that it would

be better to first agree on recommended guidance internally, and then seek public input.

Nevertheless, information regarding the FLAG effort has been available on the agencies’ web

sites since December 1997; papers regarding the effort have been presented at professional

association meetings (e.g., Air and Waste Management Association); and status has been

reported regularly in the trade press (e.g., Environment Reporter, Clean Air Report). Once the

FLMs developed the draft guidance contained in the October 1999 Draft Report, the public

received notice that the draft report was available through publication in the Federal Register.

The Federal Register notice also announced an opportunity to comment and to discuss the FLAG

report with the agencies at a public meeting. A 90-day public comment period was provided to

obtain input from other interested parties. The FLMs considered all comments received, and

revised the report where appropriate.

7. Comment: FLAG should not review BACT nor LAER determinations.

- and -

8. Comment: Regarding applicants obtaining emission offsets, States should not require

emission offsets if the source would not cause an adverse impact on an AQRV by itself.

Response: The FLMs can review BACT and LAER determinations just like any other interested

party can. In addition, the role of the FLM regarding permit conditions is to make

recommendations to the permitting authority that will protect or benefit AQRVs. Often the intent

of FLM recommendations and comments regarding permit conditions is to mitigate impacts to

AQRVs or prevent an adverse impact determination. The FLM does not determine what permit

conditions will be required or administer permit conditions; that is the responsibility of the

permitting authority. The final FLAG report makes this distinction clear in Appendix D,

paragraph 3, regarding BACT, and in the discussion of offsets and LAER under Reducing

Pollution in Nonattainment Areas (see page 17, section f, last sentence of first paragraph).

Nevertheless, in the final report, the FLMs added the following further clarification to the

discussion of air pollution permit conditions that benefit Class I areas:

Pg. 16, “e. Air Pollution Conditions that Benefit Class I Areas”

Added as new opening sentence:

"The FLM does not determine what permit conditions will be required or administer

permit conditions; that is the responsibility of the permitting authority."

Reworded original sentence (to become 2nd sentence of paragraph 1, section e.):

"However, the FLMs view the inclusion of certain PSD permit condition by the

permitting authority as a means to help protect or enhance the conditions of AQRVs

when:"

9. Comment: FLMs need to address/better address fire emissions. Fire emissions can be

significant and their impacts should be addressed.
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Response: As stated in the FLAG report, the goal of FLAG is to develop a consistent approach

on how FLMs evaluate the impacts of air pollution on public land resources with major emphasis

on new source review under the Clean Air Act. Fire can have significant short-term impacts on

visibility. However, fire and other temporary non-stationary sources are not considered under

the new source review requirements of either EPA or States and, accordingly, the fire section in

the FLAG report is not extensive.

Nevertheless, there are other venues where FLMs, in concert with EPA and States, are trying to

better address fire emissions. For example, EPA’s “Interim Air Quality Policy on Wildland and

Prescribed Fires, April 23, 1998” considers the impacts of smoke from fire. This policy was the

product of deliberations between FLMs, EPA, industry, and other stakeholders..

Also, the emissions from fire and their impacts are currently undergoing review by the Fire

Emissions Joint Forum as directed by the Western Regional Air Partnership (WRAP). The

WRAP is a group comprised of 12 Western States, and a number of tribal nations, FLMs, and

EPA. A major goal of the WRAP is to carry out the recommendations of the Grand Canyon

Visibility Transport Commission, which determined that fire could have significant, albeit

infrequent, impacts on visibility, but it also acknowledged the need for fire in ecosystem

management.

Finally, States are required to consider smoke management in developing their State

Implementation Plans for regional haze. It will be during the development of those plans that the

specific impacts of fire will be addressed.

10. Comment: More discussion is needed regarding FLAG’s relationship to other regulatory

programs (e.g., Regional Haze Rule, NEPA, NSR Reform).

Response: The FLMs added the following clarifying language as a new paragraph at the end of

section “3. LEGAL RESPONSIBILITES” (see page 5 of the final FLAG report):

It is important to emphasize that the FLAG report is only a guidance document. It is

separate from Federal regulatory programs. The scope of the FLAG report is to provide a

more consistent approach for the three FLM agencies to evaluate air pollution effects on

their resources, and to provide guidance to permitting authorities and permit applicants

regarding necessary AQRV analyses. Although FLAG strives to be consistent with

regulatory programs and initiatives such as the Regional Haze Rule and New Source

Review Reform, no direct ties exist between FLAG and these regulatory requirements.

11. Comment: FLAG is not consistent with Federal authority under the Property Clause of the

Federal Constitution because the FLMs are not authorized to regulate non-Federal property.

Response – The FLAG Report is in no way intended to regulate non-Federal property. FLAG is

merely a guidance document.
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Individual, Non-repeated, Comments and FLM Responses

Note: FLM Reviewers of the public comments attempted to provide responses to all of the

repeated themes. Of the remaining comments, the FLMs focused on those that suggested that the

FLMs were proposing guidance that was either:

(1) arbitrary and capricious, or

(2) beyond the FLM's authority.

1. Comment: "Err on side of protecting AQRVs" quote is not indicative of Congress' true intent.

Response: FLMs disagree with this point; the Legislative history supports the FLMs' position

regarding Congressional intent (see page 5 of the FLAG final report).

2. Comment: FLMs' attempt to coerce research funding through the permitting process is not

appropriate.

Response: In certain situations, the FLMs may request that the permitting authority require

permit applicants to conduct post-construction air quality/AQRV monitoring and/or studies. If

the FLMs can convince the permitting authority that such monitoring/studies are needed in order

to determine the effect emissions from a proposed source may have on an AQRV, the permitting

authority could include such requirement as a permit condition. This is consistent with the postconstruction monitoring provisions of the PSD regulations (see 40 CFR 51.166(m)(2)).

Examples of such monitoring/studies could include the applicant installing a nephelometer,

conducting a stream acidification study, performing a fumigation study to assess ozone

exposure/response effects, conducting ambient ozone monitoring, etc.

3. Comment: FLMs should not only focus on PSD sources but should also work with States to

develop SIPs targeted at minor and grandfathered source reductions.

Response: This is beyond the scope of FLAG, but the FLMs do work with the States to address

the impacts from minor and grandfathered sources.

4. Comment: Supports emissions offsets, but FLAG must clarify how such a program would be

administered.

Response: The State/permitting authority would administer any such program.

5. Comment: Definition of AQRVs and the criteria for identifying them need to be sharpened.

Response: The AQRV definition in FLAG is consistent with definitions that appear in other

publications and is adequate as written.

6. Comment: A clearer process for identifying "adverse impact" is needed.
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Response: FLAG provides more certainty to the adverse impact process and is adequate as

written.

7. Comment: Focusing on nonattainment areas and seeking SIP revisions is a waste of the

FLMs time --they should focus on their own responsibilities.

Response: FLM responsibilities include the review of SIP revisions, because minimizing the

effects of pollutants from nonattainment areas on AQRVs are most effectively addressed through

the SIP revision process.

8. Comment: It is troublesome that the FLMs refuse to prioritize AQRVs.

Response: The FLMs consider all AQRVs equally important.

9. Comment: Key information is missing from the FLAG report on which the public cannot

comment.

Response: Key information currently available can be found on NPS, FWS, and FS air resource

websites. However, all of the information that the FLMs wish to be there is not there at the

current time. The websites are “works in progress” and will be fully populated once the

information becomes available.

10 Comment: What is the basis for requiring States to revise their SIP to eliminate increment

violations even though the FLM certified no adverse impacts for a new source?

Response: A FLM certification of no adverse impacts for a specific source does not relieve the

State of the requirement to revise its SIP to correct Class I increment violations (see 40 CFR

51.166(a)(3)).

11. Comment: How would any post-construction monitoring data affect the new source if high

levels were monitored?

Response: Post-construction monitoring is a permitting authority decision, not the FLMs.

However, the FLMs assume the permitting authority would use any such data to make any

necessary revisions to its SIP, which may affect equally the new source as well as existing

sources.

12. Comment: FLAG should clarify that the States, not the FLMs, have the statutory authority to

make a final determination that a source will have an adverse impact.

Response: The CAA legislation speaks for itself with regard to respective authorities. FLAG

does acknowledge that the permitting authority has the ultimate responsibility to issue or deny a

permit. However, FLMs have the responsibility to determine that a source will have an adverse

impact on our AQRVs, whether the permitting authority agrees or not.
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13. Comment: FLAG recommendations would usurp state authority and exceed FLM authority

given them in the CAA by establishing standards that are more stringent than NAAQS.

Response: FLAG does not establish any standards.

14. Comment: FLAG should address how and when methodologies and AQRVs will be revised.

Response: The FLMs added the following language as a new section regarding Phase I updates

(see page 149 of the FLAG report):

"The FLAG Phase I report is intended to clearly state FLM guidance regarding

NSR/PSD as it exists in December 2000. As the FLMs learn more about how to

better assess the health and status of AQRVs, and as EPA produces new modeling

tools, the FLAG guidance will be revised accordingly. As periodic revisions

become necessary, any such revisions will be made to the web-based FLAG

report. Any revisions to the report will be clearly stated on the FLAG web site.

Additionally, once EPA promulgates the New Source Review Reform regulations,

the FLMs may need to revise the FLAG Phase I report to address any

inconsistencies that may result."

15. Comment: The requirement for cumulative assessment of visibility and AQRV impacts, and

consideration of applying better than BACT controls and obtaining emission offsets, are

inconsistent with WY and EPA regulations.

Response: FLAG guidance is consistent with EPA's regulations and guidance. The FLMs

assume that Wyoming's regulations are, at a minimum, as stringent as EPA's regulations.

16. Comment: It would be helpful to provide the procedures used to identify the applicable

AQRVs for each Class I area and a reference as to where a current AQRV list can be obtained.

Response: Page 6 of the FLAG Report (a. Identifying AQRVs) discusses the procedures used to

identify AQRVs. USFS AQRV information is listed on their website for each Class I area. The

NPS and FWS websites are under construction. Nevertheless, the FLMs recommend that

interested parties contact them directly for current information on AQRVs for specific Class I

areas.

17. Comment: FLMs should announce preliminary adverse impact determinations in the Federal

Register so public can comment.

Response: The permitting procedures included on pages 13 and 14 of the FLAG report provide

for separate notice in the Federal Register, if time permits and the permitting authority does not

provide adequate public notice and participation.

18. Comment: FLAG fails to establish deadlines for FLM action.

Response: The FLMs operate within permitting authority mandated deadlines.
14

19. Comment: Recommend that FLMs consider incentives to industry, i.e., the FLM could agree

to a decreased review time and acceptance of a project if the facility included LAER and agreedupon offsets in the initial application.

Response: This is a constructive comment that the FLMs will consider doing on a case- by-case

basis.

20. Comment: FLMs should publish AQRVs in the Federal Register for public comment.

Response: The public has been involved in AQRV identification in the past. There have been

appropriate opportunities for public involvement, and the FLMs will continue to provide such

opportunities.
15

C. RESPONSE TO VISIBILITY COMMENTS

This section identifies, and responds to, “recurring themes” found throughout the public

comments on the visibility section of the draft FLAG Phase I report.

1. FLAG is Inconsistent with EPA's Regional Haze Rule (RHR)

Basis for Comments: 1) FLAG’s definition of “current conditions” for evaluating possible new

source impacts is not defined as the mean of the 20% best days, one of the

key metrics used in the EPA regional haze rule.

2) FLAG uses extinction and not deciview as its visibility metric.

3) FLAG should defer to RHR for visibility protection, not PSD.

4) FLAG recommends using 24-hour averages, not annual averages.

General Response: Several commenters raised concerns over perceived conflicts with FLMs'

approaches to assessing visibility impacts and the way in which “reasonable progress” is

addressed in EPA’s regional haze rule. It is important to distinguish between the visibility

protection provisions under PSD and those of the regional haze rule. In general, the FLMs feel

there is no conflict between the procedures described in the FLAG report for reviewing the

impacts of major new sources on visibility and the provisions of the regional haze rule which

apply to States to develop plans to address regional haze conditions. The overall goal of

visibility protection, as set forth in 40 CFR Part 51, Subpart P, is to ensure reasonable progress

toward the national visibility goal of no man-made impairment in the Class I areas. The

provisions of Subpart P include addressing existing sources of “reasonably attributable

impairment,” conducting reviews under the Prevention of Significant Deterioration and New

Source Review programs for visibility impacts, and implementing the regional haze rule to

address existing source impacts on regional haze. The regional haze rule did not change the

mechanisms or requirements for FLM participation in and review of major new sources that may

affect visibility in Class I areas. As noted in the preamble to the regional haze rule (64 FR

35715) “(t)oday’s final rule established a comprehensive visibility protection program for Class

I areas.”(emphasis added) The EPA left in place all of the 1980 provisions linking a visibility

review of major new sources to State requirements for visibility protection as a means to assure

protection of the clearest days as well as the entire distribution of visibility conditions.

Responses to specific issues:

Issue 1: FLAG’s definition of “current conditions” for evaluating possible new source impacts is

not defined as the mean of the 20% best days, one of the key metrics used in the EPA regional

haze rule.

Response: The goals of new source review for visibility impacts are to assure that new sources,

many of which will be operating for decades, do not interfere with the goals of the visibility

protection program which is to work toward no man-made impairment. The regional haze rule
16

tracks the 20 percent clearest days to ensure that programs designed to address the haziest days

are not simply set up to “redistribute” effects from the haziest to the clearest days, but in fact

improve the entire distribution. The new source review assessment of a single new source

should assure that it will have the least effect on the clearest of days so that it does not interfere

with the overall long-term goals of the visibility protection program.

The RHR establishes a simple metric for tracking progress towards the national visibility goal of

no man-made impairment. The rule selects the mean of the 20% clearest days and the mean of

the 20% haziest days, as determined from “reconstructed” extinction based on 24-hour

monitored particle concentrations (expressed in deciviews), as the means for tracking this

progress.

The FLMs considered using the mean of the clearest 20% days as the FLAG benchmark, but

discarded this option because this value often represented severely impaired conditions. It did

not seem appropriate that the FLMs not object to an industrial expansion, thereby allowing

current conditions to worsen, just because the current conditions were so hazy that the new

source's projected contribution might not be evident. Estimated natural background (which is

also the long-term goal expressed in the RHR) seemed a more appropriate benchmark.

Issue 2: FLAG uses extinction and not deciview as its visibility metric.

Response: In the case of regional haze, tracking the deciview scale is appropriate for tracking

how uniform changes in atmospheric extinction resulting from broad regional changes in

emissions affect visibility perception of scenic vistas. However, when reviewing the impacts of

a single source, as in the new source permit review procedures, the impacts should be assessed

for specific impacts on sight paths and views as well as haze effects caused by that source in a

specific Class I area usually less than 300 km away. Changes in extinction coefficients are the

better metrics for this type of haze impacts.

The FLMs considered the use of the deciview (dv) metric, but discarded it for new source review

applications. The dv is appropriate for the RHR, which addresses visibility impairment across

very broad geographic regions due to emissions from sources widely distributed and frequently

long distances away. The FLAG prescription is intended for use in new source review

applications for sources, at most, 300 km away. The prescription presented in the FLAG report

does not address regional haze assessments; consequently, the FLMs recommended the

fundamental extinction coefficient as its metric. In any case, the dv and the extinction

coefficient are related by a simple mathematical transformation.

Issue 3: FLAG should defer to the regional haze rule for visibility protection, not PSD and NSR.

Response: EPA did not change the PSD and NSR requirements for visibility assessment of major

new sources at Class I areas when it revised the overall visibility protection program

requirements. The regional haze rule relies on new source review requirements as part of the

suite of requirements which work towards the national goal, and in particular, assures that the

clearest days, if near natural conditions, remain that clear. In addition, for areas where even the

clearest measured days are impaired by man-made emissions, the PSD and NSR review
17

processes will assure that new sources do not prevent the attainment of the national goal of

having those days move towards natural conditions.

Issue 4: FLAG recommends using 24-hour averages, not annual averages like the regional haze

rule.

Response: The regional haze rule uses daily monitored data to review the distribution of the

clearest and haziest day over a long-term planning horizon. The use of 24-hour data as the basis

for assuring that new source impacts are minimal assures the ability to prevent new sources from

have a detrimental effect on any part of the distribution of days which are to be improved over

time by the regional haze program.

The CAA through the PSD provisions direct the FLMs to exercise affirmative action to protect

natural resources for possible injury due to new sources. This responsibility must be carried out

in the new source review process and would not be effectively addressed by the long-term RHR

provisions. Furthermore, the FLMs are not confident that any averaging time longer than 24-

hours would be useful for gauging the contribution of a specific source to visibility impairment

in a specific Class I area.

2. Issues Associated with Natural Background Estimates

Basis for Comments: 1) FLAG's assumed natural background estimates are arbitrary.

2) Regional NAPAP estimates are not representative of specific Class I

areas and should be improved. The temporal and spatial resolution as well

as the overall accuracy of NAPAP natural background estimates are poor.

3) Alternatives are available that are better estimates for certain Class I

areas. For example, Grand Canyon Visibility Transport Commission

estimates, or clearest conditions based on site-specific monitoring data,

may be better for some western Class I areas.

4) The Rayleigh component is set at 10 Mm-1 nationwide, yet it can vary

with elevation.

5) Contribution of smoke from fires is not included in background

estimate.

6) The EPA document, Workbook for Plume Visual Impact Screening and

Analysis (Revised), provides values that are different than those proposed

in FLAG.

7) The FLMs have no authority to change EPA guidance.

8) The IWAQM Phase 2 report uses different background visibility values.
18

General Response: The most appropriate visibility goal and benchmark for visibility assessment

is one representative of the clearest possible conditions. Therefore, the FLMs have based their

recommended new source assessment prescription on natural background reference levels. In

addition, EPA guidance on background conditions is flexible and does not preclude the use of

different estimates of the background visibility than is described in the various documents.

Responses to specific issues:

Issue 1: FLAG's assumed natural background estimates are arbitrary.

Response: The FLMs recognize the uncertainty associated with estimating natural background

for specific Class I areas. The FLMs also understand that the EPA, as part of the RHR

implementation, will be providing guidance on how to estimate natural background. Until EPA

provides this guidance, the FLMs have chosen to rely on the particulate concentration estimates

derived and published by NAPAP (NAPAP, 1990).

Issue 2: Regional NAPAP estimates are not representative of specific Class I areas.

Response: The FLMs recognize that the NAPAP background visibility estimates (including both

particle concentrations and estimated humidity effects) are not Class I area specific. The FLMs

did refine these estimates to a degree by using interpolated site specific relative humidity data.

Issue 3: Alternatives are available that are better estimates for certain Class I areas.

Response: As stated elsewhere in this response, the FLMs considered using the mean of the

clearest 20% days as the FLAG benchmark, but discarded this option because this value often

represented severely impaired conditions. The FLMs will reconsider their assumptions for

estimated natural condition estimates when EPA provides its technical guidance on the Regional

Haze Rule.

Issue 4: The Rayleigh component is set at 10 Mm-1 nationwide, yet it can vary with elevation.

Response: The FLMs have adopted a constant Rayleigh contribution to extinction, as practiced

by IMPROVE. If the forthcoming EPA guidance recommends an elevationally adjusted Rayleigh

term, the FLMs will adopt that recommendation.

Issue 5: Contribution of smoke from fires is not included in background estimate.

Response: The FLMs recognize that smoke has been for the most part omitted from the NAPAP

estimates. Only the elemental carbon contribution of smoke from wildland fires was addressed.

However, the FLMs are not aware of the availability of better estimates. EPA guidance is also

forthcoming on what types of smoke will be considered “natural” and the contribution of this

category to natural background.

Issue 6: The EPA document, Workbook for Plume Visual Impact Screening and Analysis

(Revised), provides values that are different than those proposed in FLAG.
19

Response: The Workbook for Plume Visual Impact Screening and Analysis (Revised) (EPA454/R-92-023) includes a map giving “default” values for background visibility. These are

based on the median observations from airport data. Those values provide an estimate of the

background visibility conditions absent other information. EPA guidance states: “In cases where

there is more applicable onsite data, source owners should consult with the Federal Land

Manager for the Class I area in question concerning appropriate regional background visual

range values for input to VISCREEN or other plume visibility models.” The FLMs consider

clean conditions to be the “appropriate regional background visual range” in these analyses and

have been using clean conditions in these analyses for many years.

Issue 7: The FLMs have no authority to change EPA guidance.

Response: The FLMs are not changing the guidance. We are following EPA guidance in using

more appropriate background visibility values; they are not changing the guidance. Furthermore,

the FLMs are charged with making the determinations on a case-by-case basis as to whether

emissions constitute an adverse affect on a Class I area, based on frequency, magnitude, and

duration of a visibility impairment. The FLAG report is simply delineating some of the criteria

the FLMs will use in making that determination.

Issue 8: The IWAQM Phase 2 report uses different background visibility values.

Response: The Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary

Report and Recommendations for Modeling Long Range Transport Impacts (EPA-454/R-98-

019) is primarily directed toward describing long-range transport modeling techniques. The

initial thrust of the IWAQM was the application of these modeling techniques to Class I area

analyses, especially the impacts on AQRVs. To that extent, the document discusses methods

that can be used to evaluate the impacts on AQRVs, including values to use for background

visibility conditions. The discussion includes: “The background conditions provided for a Class

I visibility analysis will be representative of clean conditions. Changes in visibility are most

sensitive under clean conditions. By using clean conditions for all comparisons in a Class I

analysis, it ensures that already clean conditions will not be impaired. Additionally, the Clean

Air Act states as a national goal that the visibility in Class I areas is to be unimpaired by manmade air pollutants and that any such impairment is to be remedied. To represent clean

conditions, the average of the cleanest 20% of the data from IMPROVE, at that site, is generally

used. Even the data from the cleanest days usually exhibit some made-made influence. This

average of 24-hour values for the 20% cleanest conditions is used as representative of a clean

background condition.”

In the course of re-examining what statistic to use to represent clean conditions during the FLAG

process, the FLMs examined the 20% cleanest conditions. It became apparent that in many

cases, the 20% cleanest measured conditions are still significantly impaired. Furthermore, when

even the 5% cleanest conditions were examined, it was evident that these data also included

significant impairment, particularly in the Eastern U.S. The FLMs do not find it appropriate to

use significantly impaired conditions as a benchmark. Therefore, the FLMs believe that an

estimate of natural conditions is the only viable value to use.
20

Furthermore, the changes between the FLAG report and the IWAQM Phase 2 report were

anticipated by IWAQM. The Phase 2 report states:

While drafting this report, the National Park Service, the U.S. Fish and Wildlife Service

and the U.S. Forest Service have been holding intensive meetings to promote a greater

consistency in the procedures Federal Land Managers use in identifying and evaluating

AQRV impacts. We have discussed in this report the assessment of regional visibility

impacts using the deciview, which at the time of the drafting of this report was the

preferred metric. As time progresses, it is looking more like the change of extinction may

become the preferred metric. Hence, although the information provided here is useful, the

details and implementation may be somewhat different as a consequence of the ongoing

discussions. For the latest information on procedures and metrics, we suggest visiting the

web site:

http://www.nature.nps.gov/ard/flagfree/index.html.

3. Issues Associated with Threshold Values

Basis of Comments: 1) FLAG's assumed visibility threshold values are arbitrary (no scientific

basis).

2) FLAG's assumed visibility threshold values are not perceptible and are

too restrictive (i.e., too low) or that they are not restrictive enough.

3) FLAG should use an averaging time for analyses longer than 24-hr in

order to avoid undue influence of extreme episodes.

4) FLMs should provide guidance on how it will assess magnitude,

frequency, duration, and geographic extent of visibility impairment to

make adverse impact determinations. Using 24-hour basis contradicts this

concept. Also, the FLMs should define the level of acceptable impairment.

5) FLMs need to provide analyses to show permitting authorities the

consequences of these thresholds.

6) The 0.4% threshold for exempting a new source from further review is

too low (not perceptible) and should be relaxed. Also, the 0.4% threshold

should be used as the trigger for cumulative analyses.

General Response: The underlying principle of the FLAG recommendation is the need to ensure

that a new source should not cause visibility impairment, either by itself or in combination with

other new sources. Toward this end, the FLMs selected levels of concern that represent values

representative of the lower end of human perceptibility and values representative of the higher

end of human perceptibility for single sources and multiple sources, respectively. The FLMs

also chose to define a de minimis level to provide a threshold below which a new source needed
21

no further visibility impact analyses, and below which the FLM was unlikely to object to the

issuance of a permit.

Responses to specific issues:

Issue 1: FLAG's assumed visibility threshold values are arbitrary.

Response: The levels of concern were selected from EPA guidance documents or the published

literature (references provided in the Phase I Report).

Issue 2: FLAG's assumed visibility threshold values are not perceptible and are too restrictive

(i.e., too low) or that they are not restrictive enough.

Response: The FLMs assert the levels are not “too low,” since they do represent the possible

extremes of human perceptibility. However, if new information becomes available, the FLMs

will take it into consideration. The selection of the de minimis level followed an approach

similar to that used by EPA in the proposed new source review reform regulations to define

significant impact levels for the PSD increments.

Issue 3: FLAG should use averaging time for analyses longer than 24-hr in order to avoid undue

influence of extreme episodes.

Response: In the context of visitation to Class I areas, visibility and human perception of the

visibility condition is actually a short-term phenomenon. Therefore, 24-hour averages, if

anything, are too long of an averaging time for visibility assessments. FLMs selected this

averaging time given the confidence in the model results for far-field applications and because it

provided a surrogate for the spatial averaging more appropriate for applying the selected

thresholds. For near-field model applications, the FLMs concur with using the 1-hour averaging

time as recommended in EPA guidance documents.

Issue 4: The FLMs should provide guidance on how they will assess magnitude, frequency,

duration, and geographic extent of visibility impairment to make adverse impact determinations.

Response: The adverse impact determination remains a case-by-case determination. Given the

multitude of possible impact combinations (i.e., magnitude/frequency), the FLMs can provide no

a priori guidance except to say that the determination will be based on the magnitude, frequency,

duration, and geographic extent of the predicted effect. The FLMs have provided the guidance

on the levels of concern and parameters that would be used to make the determination. For

example, the FLM could make a determination based on the number of 24-hour estimates of

extinction over the level of concern, the amount over the level of concern, or the duration of

multi-day episodes.

Issue 5: FLMs need to provide analyses to show permitting authorities the consequences of these

thresholds.
22

Response: Permitting authorities should already be familiar with applying steady-state models to

assess near field impacts, so the FLMs did not feel it was necessary to provided any sample

applications. For the less familiar distant/multiple-source applications, very detailed guidance,

including one sample application, has been provided in the FLAG report. The consequences of

applying the recommended prescription are strongly dependent on meteorology, the number and

distribution of sources, distance to Class I areas, and emissions. Therefore, it would not be

possible to meaningfully represent the wide range of possible scenarios. Qualitative assessments

of the consequences are probably possible because the basic prescription has been in use by the

FLMs (and some permitting authorities) for several years.

Issue 6: The 0.4% threshold for exempting a new source from further review is too low (not

perceptible) and should be relaxed.

Response: The 0.4% threshold was established in order to exempt sources from further review if

they are not a major contributor to a circumstance where visibility impairment due to new source

growth exceeds a 10% change in extinction. The FLMs' desired condition would be to see no

contribution in this case, but are willing to accept practical considerations in setting this

threshold. Hence, the threshold was set purposefully low, but not zero. As the FLMs gain more

experience with the application of this threshold, it will be revisited to ascertain whether it is

achieving a desired level of protection. 

The FLMs rejected the recommendation of using this threshold as the sole basis of determining

the need for conducting cumulative analyses.

4. An Annual Reference Level is Inappropriate for the FLAG Visibility Application.

Basis for Comments: 1) Comparison of an annual average estimate of natural conditions with a

24-hour average model concentration is inappropriate.

General Response: Estimates of natural conditions are only available as estimates of the longterm average.

Responses to specific issues:

Issue 1: Comparison of an annual average estimate of natural conditions with a 24-hour average

model concentration is inappropriate.

Response: There will obviously be some fluctuation about the mean of the annual average, but

how that would vary on any given day is unknown. The average conditions could occur on any

given day. The FLMs see no viable alternative to comparison with an annual average number.

5. CALPUFF is not Suited for the Task Described

Basis for comments: 1) CALPUFF is inappropriate for visibility calculations greater than 50

kilometers.

2) CALPUFF can not be used for multiple source impacts.
23

3) The sulfate chemistry in CALPUFF underestimates aqueous phase

formation and overall chemical processes are treated too simply.

4) The maximum applicable distance of the modeling system needs to be

defined.

5) CALPUFF is too resource intensive; it requires special computers with

gigabytes of memory.

6) Requiring 5 years of meteorological analysis is too onerous.

7) CALPUFF is not applicable to oil and gas operations.

General Response: There are a number of contentions about the suggested use of CALPUFF as a

tool for analyzing visibility impacts for source/receptor pairs at distances beyond 50 kilometers.

Commenters dealing with the general applicability of the model should refer to the Interagency

Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and Recommendations

for Modeling Long Range Transport Impacts (EPA-454/R-98-019). That document should help

make it clear that the modeling system is well suited for the task at hand; that is, calculating

concentrations of visibility impairing pollutants, both primary and secondary, from single or

multiple sources, at distances within and beyond 50 kilometers. This was the goal of the

IWAQM.

The CALPUFF modeling system was proposed as a long-range transport model by the EPA

during the seventh modeling conference. (See Federal Register, Vol. 65, No. 78, Friday, April

21, 2000, Proposed Rules, pages 21506-21546.) FLAG is essentially using the model as the

EPA proposes it for use.

Responses to specific issues:

Issue 1: CALPUFF is inappropriate for visibility calculations greater than 50 kilometers.

Response: The CALPUFF modeling system is being proposed by the EPA as the refined

modeling tool for analyzing long-range transport, defined as transport beyond 50 kilometers.

Again, please refer to the Federal Register, Vol. 65, No. 78, Friday, April 21, 2000, Proposed

Rules, pages 21506-21546. The commenters are also referred to the Interagency Workgroup on

Air Quality Modeling (IWAQM) Phase 2 Summary Report and Recommendations for Modeling

Long Range Transport Impacts (EPA-454/R-98-019).

Issue 2: CALPUFF can not be used for multiple source impacts.

Response: CALPUFF treats multiple sources and multiple source types. The commenters are

referred to the references above and to the CALPUFF users guide available at:

http://www.src.com/calpuff/calpuff1.htm

The comments about multiple sources are based on a single quote taken out of context pertaining

to the screening mode. In context the quote should read:
24

All of the reviewers expressed concerns regarding the use of the screening technique.

They agreed that it was inherently conservative (would provide estimates of impacts

greater than likely would result if a more refined analysis was performed), but also

recognized that it could not be guaranteed to always yield conservative concentration and

deposition flux impacts. They suggested that if the screening technique is recommended,

it should be made clear that it may not provide conservative impact estimates, and that

the technique is applicable for one or several closely spaced sources of emissions (not for

multiple sources that are widely spaced around a Class I area).

The FLMs agree that the constraint on the screening mode is appropriate.

Issue 3: The sulfate chemistry in CALPUFF underestimates aqueous phase formation and overall

chemical processes are treated too simply.

Response: Several commenters indicated that the model does not adequately handle aqueous

phase conversion of sulfur dioxide to sulfate. This is an area where the model is likely to

underestimate impacts of visibility impairing pollutants. The FLMs have long recognized this

and have considered it an area that needs improvement. In the interim, however, the FLMs have

considered the estimates from the CALPUFF system to be preferable to no estimates at all, and

are willing to abide by those results.

There are more sophisticated chemical treatments available in various models than are currently

available in CALPUFF. If an applicant wishes to use a more detailed chemical scheme and it is

deemed technically appropriate, its use would certainly be entertained. The suggested modeling

schemes put forth in FLAG are not meant to be the only alternatives for analyzing visibility

effects.

Issue 4: The maximum applicable distance of the modeling system needs to be defined.

Response: The FLAG report did not specify how far beyond 50 kilometers the model should be

applied. The formulation of the model allows for receptors to be placed at any distance from a

source, from meters to hundreds of kilometers. The model can readily be applied to distances up

to 300 kilometers. The latest revision of the model contains horizontal and vertical puff splitting

algorithms that help compensate for wind shear when puffs travel great distances. At this time

there is no recommended maximum limit, although the maximum distance for most applications

will be between 200 to 300 kilometers.

Issue 5: CALPUFF is too resource intensive; it requires special computers with gigabytes of

memory.

Response: With respect to the resources required to do a cumulative analysis, the model runs

easily on any Pentium class computer, with 128Mb of memory. Disk storage used to be an issue,

however, one can obtain disk drives in excess of 30Gb for a few hundred dollars. Most of the

resources involved in running the model involve obtaining the appropriate data and putting in the

proper formats for input to the modeling system.
25

Issue 6: Requiring 5 years of meteorological analysis is too onerous.

Response: With respect to the amount of meteorology to be analyzed (5 years), FLAG is simply

following the recommendations of the IWAQM and EPA's proposed modeling guidance for

using the CALPUFF model. Those documents allow the use of hourly meteorology if Four

Dimension Data Assimilation (FDDA) prognostic model output is used.

Issue 7: CALPUFF is not applicable to oil and gas operations.

Response: One concern raised about applying CALPUFF to oil and gas operations was that

CALPUFF was not the most appropriate model for treating multiple small sources, such as are

found in oil and gas development. The contention was that treating multiple plumes or

aggregations of plumes was only appropriate for major sources. The methodology outlined in

FLAG tried to identify the visibility calculations from CALPUFF by plume phenomena. In

general, a haze is considered to be a relatively uniform distribution of pollution over great

distances. The CALPUFF model by its construction treats the emissions from all sources as a

series of discrete puffs to represent a plume. Thus, the discussion of discrete plumes or

aggregation of plumes was simply intended to distinguish the modeled phenomena from a haze.

There is nothing inherent in the model that would restrict its use only to major sources.

The comments regarding oil and gas development specifically mentioned some analyses done

with CALPUFF in Wyoming. The FLMs feel that those efforts have been successful and

validate the use of CALPUFF for those types of applications. Other modeling techniques, such

as a grid model, may be appropriate in some applications. However, the FLMs feel that for the

permit and EIS related applications discussed in FLAG that the CALPUFF model is a useful

tool. The FLMs do not intend to preclude a more sophisticated modeling approach by an

applicant if it is deemed appropriate.

6. There Should Not be Different Contrast and Color Thresholds for Screening and

Refined Near-field Analyses

Basis for Comments: 1) The FLAG visibility guidance is inconsistent with EPA Guidance.

2) Using more than one threshold is confusing.

General Response: The thresholds used in visibility analyses are tied to the potential for a plume

to be visible to an observer; those thresholds cover a range of values. In a screening analysis,

conservative assumptions are used to estimate the pollutant concentrations and optical

parameters, therefore, a higher threshold is used, recognizing the conservative nature of the

analysis. For more refined analyses, more mid-range values are used, since the techniques are

not as conservative.

Responses to Specific Issues:

Issue 1: The FLAG visibility guidance is inconsistent with EPA Guidance.
26

Response: The FLMs followed the EPA guidance explicitly in setting the threshold levels for

the near-field analyses. The EPA guidance is found in several documents. The document most

people initially turn to is the Workbook for Plume Visual Impact Screening and Analysis

(Revised) (EPA-454/R-92-023). This document describes Level 1, Level 2, and Level 3

analyses. Level 1 and Level 2 analyses use the VISCREEN model, and Level 3 analyses suggest

using a more refined analysis tool, such as PLUVUE II. The guidance for running the PLUVUE

II model is found in the User’s Manual for the Plume Visibility Model, PLUVUE II (REVISED)

(EPA-454/B-92-008) and in Addendum to the User’s Manual for the Plume Visibility Model,

PLUVUE II (REVISED) (EPA-454/B-95-001). The recommended thresholds are also included

in these documents.

The Workbook for Plume Visual Impact Screening and Analysis (Revised) tries to “characterize

our current understanding of perceptibility:”

Contrast ΔE

Lower-bound threshold 0.005 0.2

Best-estimate threshold 0.02 0.8

Upper-bound threshold 0.05 2

The document goes on to say, “For Levels 1 and 2 plume visual impact screening, we

recommend that the higher set of threshold values (contrast of 0.05; ΔE of 2) be used as the

criteria for screening.”

For Level 3 analyses, the PLUVUE II model is suggested. When discussing plume perceptibility

the Addendum to the User’s Manual for the Plume Visibility Model, PLUVUE II (REVISED)

states: “Plumes that subtend angles between roughly 0.1 and 1 degree and have contrasts with

absolute values greater than 0.02 are generally perceptible. A two percent contrast is used to

define visual range.” For the color contrast parameter it states, “Under ideal viewing conditions,

when the viewing background is uniform and the plume is sharp-edged, a just perceptible ΔE

would be equal to one. For cases of plumes with diffuse edges that subtend angles between

roughly 0.1 and 1 degree, a just perceptible ΔE threshold would be greater than one, perhaps

two.”

The FLMs have only indicated that they will continue to use the threshold levels suggested by

EPA: |C|=0.05 and ΔE=2 for Level 1 and 2 analyses and |C|=0.02 and ΔE=1 for Level 3 analyses.

The FLMs recognize that there are conditions where somewhat higher thresholds may apply and

would consider those cases when those conditions occur. There are also cases where much lower

thresholds are appropriate. As a first step, the FLMs anticipate that the aforementioned criteria

will be used unless other, technically defensible criteria apply.

Issue 2: Using more than one threshold is confusing.

Response: The different levels are used when modeling techniques are changed, going for

VISCREEN to PLUVUE II. It should not be difficult to deal with changing thresholds when

switching modeling techniques. FLAG does recognize that by using different thresholds one

might be in the situation of passing a screen, but ultimately failing the refined analysis. It is
27

unlikely that an applicant will go on to do a refined analysis if the screening analysis indicates

there is not a problem. Since all decisions are on a case-by-case basis, depending on magnitude,

frequency and duration, this would be a factor to be considered when the FLMs make their

decision.

7. Emission Decreases need to be Considered

Basis for comments: 1) FLAG needs to account for emission decreases to avoid penalizing new

sources when significant emission decreases have occurred.

General Response: The basis for the prescription outlined in FLAG for visibility analysis is to

ensure that the national visibility goal, “no manmade impairment,” is not hampered by new

source growth.

Responses to specific issues:

Issue 1: FLAG needs to account for emission decreases to avoid penalizing new sources when

significant emission decreases have occurred.

Response: The issue of accounting for emission decreases in the visibility analyses was raised.

As the prescription is currently defined, there is no opportunity to account for emission decreases

since the recommended background condition used for comparison is “natural,” which by default

has no emissions to decrease. When doing a cumulative analysis it is recommended that all new

source growth be considered. Any sources that would have been in that category, but have been

decommissioned would not be included in the analysis.

8. Cumulative Analysis is Not Possible Using Near-field Visibility Models and Parameters

Basis for Comments: 1) It is not practical to calculate contrast and ΔE for multiple plumes.

General Response: The FLMs agree that the plume visibility models are not suited for simulating

the effects of multiple plumes. FLAG's recommendation suggests that a multiple source model,

such as CALPUFF, be used to perform multiple source impact analyses. The FLMs are

recommending that extinction be the visibility parameter used for these multiple source analyses,

rather than the more traditional contrast and ΔE parameters.

Responses to specific issues:

Issue 1: It is not practical to calculate contrast and ΔE for multiple plumes.

Response: The FLMs have a real concern about multiple source impacts, from both near-field

and far-field sources. The proposed methods are reasonable for analyzing this situation. The

CALPUFF model, suggested for multi-source applications in the report, is ideally suited for

providing the ambient concentrations to calculate visibility impairment for multiple sources. The

Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and

Recommendations for Modeling Long Range Transport Impacts (EPA-454/R-98-019) discusses
28

local-scale impacts and “...is recommending the use of the CALPUFF modeling system for the

characterization of all sources being explicitly modeled. . .A benefit of using one model for all

sources is that CALPUFF has the MESOPUFF II chemistry, which provides characterization of

pollutant species that are not treated by currently available local-scale models...” The

recommendation is primarily contemplating what to do for cases where long-range transport and

local sources can impact an area simultaneously, but these techniques are equally applicable to

multiple sources in the near-field alone.

Light extinction was chosen as the visibility parameter to analyze because it can be relatively

easily calculated from the pollutant components derived from CALPUFF. This parameter may

not be the best choice for examining the effects of a near-field analysis. However, multiple

source impacts, even from relatively near sources, are going to be somewhat more diffuse than a

single source due to different source locations and due to differences in stack height and plume

rise between sources. Therefore, using light extinction, rather than contrast and ΔE is

reasonable. It must be noted, that the technique as currently outlined, only accounts for groundlevel concentrations. Lofted plumes are not considered, thus potentially grossly underestimating

the potential impacts of multiple near-field sources. Thus, it may be necessary to conduct both

single-source impact analysis with a plume visibility model as well as a multiple source analysis,

using CALPUFF.

The near-field, multiple-source analysis techniques have not been widely tested. The visibility

thresholds used for long-range transport analyses may not be as applicable for the near-field

analysis, but will be applied as an initial screening criteria. Further refinement of this technique

needs to be conducted.

8. NO2 Should be Included in the Distant/Multi-Source Prescription

Basis for comments: 1) Nitrogen dioxide is often present in measurable concentrations in

Class I areas located near source areas and should be considered.

General Response: As originally conceived, the Distant/Multi-Source Prescription was only

going to be applied for distant sources. For those situations, NO2 is not usually a significant

contributor to overall light extinction. However, when applied to sources locating near Class I

areas or for Class I areas located near source areas, the FLMs agree that NO2 may be a

contributor to visibility impairment and should be included in the prescription.

Responses to specific issues:

Issue: Nitrogen dioxide is often present in measurable concentrations in Class I areas located

near source areas and should be considered.

Response: The FLMs need to provide an NO2 extinction value to use in the multi-source, near

field analysis. The following relationship should be used for cases where NO2 is a contributor to

light extinction: bNO2 = 0.17 [NO2] Where bNO2 is in Mm-1 and [NO2] is in μg/m3 (Based on

Workbook for Plume Visual Impact Screening and Analysis (EPA-450/4-88-015).
29

10. Issues Regarding Relative Humidity (RH) Factors

Basis for Comments: 1) RH has diurnal, seasonal, and elevational differences which are not

represented by annual average regional values.

2) The RH regimes identified in the appendix are too coarse.

3) FLAG should use only daytime RH.

4) Averaging 1-hour values of extinction is preferable to using 24-hour

average aerosol concentrations and applying an annual f(RH).

General Response: The draft FLAG recommendations indicated that the preferred relative

humidity adjustment factor (f(RH)) to use in visibility analyses should be obtained from annual

average regional values in the appendix. The option was left open to use the hour-by-hour RH

values used in the modeling to calculate hour-by-hour f(RH) and hourly extinction. Based on

comments, the FLMs now recommend using the hour-by-hour values as the preferred method,

allowing the annual average values in the appendix to be used if the hourly values are not

representative. For the distant screening analysis, FLAG still recommends using the annual

average values in the appendix.

Responses to specific issues:

Issue 1: RH has diurnal, seasonal, and elevational differences which are not represented by

annual average regional values.

Response: The revised recommendation is to use the temporally and spatially varying relative

humidity fields from the model. To the extent possible, RH data representative of the Class I

area should be included in the input fields for the model. This will help alleviate the concerns

raised about the diurnal, seasonal, and elevational differences.

Issue 2: The RH regimes identified in the appendix are too coarse.

Response: The FLMs agree that the broad RH regions presented in the draft recommendations

were not appropriate. To correct this deficiency, the revised recommendation is to use the

spatially and temporally varying RH data used in the modeling for refined analyses and to use

seasonal values of f(RH) based on interpolated observations of RH for screening analyses.

Issue 3: FLAG should use only daytime RH.

Response: Some commenters suggested only using day-time RH values in the analysis. Aerosol

growth occurs throughout the night due to increased RH. This can dramatically affect the

visibility in the early morning and later in the day as pollutants are transported.
30

Issue 4: Averaging 1-hour values of extinction is preferable to using 24-hour average aerosol

concentrations and applying an annual f(RH).

Response: The FLMs agree that averaging 1-hour average extinction values is the preferred

method for calculating light extinction. The suggested modeling system allows for this and is the

revised recommendation for refined analyses.
31

D. RESPONSE TO OZONE COMMENTS

This section provides FLM responses to public comments received on the ozone chapter of the

draft FLAG Phase I report. The section is organized by key issues raised by the commenters.

1. Ozone Effects Modeling

Comment: With limitations, models are available for estimating ozone from single sources; the

report should recommend dispersion models to use to demonstrate that NOx emission offsets will

benefit the FLM area.

Response: The commenter lists the limitations of available models for estimating ozone, and

further suggests that “Absent of model validation and emission inventory efforts, applying these

atmospheric models to Class I and other remote areas may not be in the best interests of the

science.” FLAG agrees that such model validation and emission inventories are not available.

Further, the EPA does not currently recommend a specific source receptor model to use for

ozone. FLAG recommends that emission offset discussions take place on a case-by-case basis,

and that, in each case, the permitting authority, EPA, and the FLM agree on the appropriate

model to use for the analysis. FLAG welcomes the input of EPA on recommended models to use.

Comment: The ozone chapter should be withdrawn until appropriate source/receptor models are

available. Recommend deleting the ozone section from the report, primarily because of the

absence of a single source model to determine impacts on vegetation. The absence of single

source models suggest it is premature to restrict PSD permits based on ozone impacts on

vegetation. Until appropriate screening models are developed, FLAG should not deal with ozone

impacts on AQRVs and should not pursue additional NOx emission controls as an ozone

reduction strategy.

Response: FLAG agrees that reliable models do not exist for single source ozone impacts. The

chapter is useful without the dispersion models to allow the FLMs to identify sensitive AQRVs

and critical levels of concern. The FLMs cannot restrict PSD permits, but only recommend

remedial action based on ozone impact on AQRVs. FLAG appreciates the commenter's

recognition that FLM needs to make timely decisions addressing ozone issues and not wait until

a regional modeling center is implemented.

Comment: The draft report says the FLM may recommend the permitting authority conduct

regional modeling if there is concern about ozone. Numerous issues would need to be addressed

before such modeling could be performed. In addition, regional modeling is resource-intensive

and would probably not be undertaken without a regulatory mandate.

Response: FLAG recognizes the difficulties associated with performing a regional modeling

analysis. Nevertheless, given that ozone is a regional pollutant, FLAG believes it is valid to

include the recommendation for regional modeling as an option to help address ozone impacts.

Comment: The effects of mobile sources of ozone formation need to be evaluated.
32

Response: Regional assessments do include mobile sources.

2. VOC/NOx Control Issues

Comment: Focusing on NOx emissions controls is a broad generalization. FLMs should state that

they are depending on VOC controls for ozone at this time. Language should be added to

recognize that ozone impacts might result from VOC emissions. Assuming all Class I areas are

NOx limited needs to be justified.

Response: FLAG recognizes that VOC emissions also contribute to ozone formation, and the

FLMs will recommend VOC controls where VOC emissions are a concern. The FLMs will also

consider any information indicating a specific area is not NOx limited.

Comment: NOx controls or offsets will be mandated by the FLMs.

Response: FLMs have no regulatory authority, and can only recommend, not mandate, emissions

controls.

Comment: FLAG’s view of ozone formation chemistry is overly simplistic, and tries to regulate

ozone precursors based on this flawed understanding.

Response: The FLMs agree that FLAG's discussion of ozone chemistry is simplistic. The FLMs

attempted to simplify the ozone discussion for the non-technical reader. FLMs do not try to

regulate, and can only recommend remedial action.

3. Regulatory Issues

Comment: The report should address the current 1-hr NAAQS.

Response: The FLMs have added a footnote to indicate that the 1-hr NAAQS is still in effect

(see page 74 of the final FLAG report).

Comment: Certain state regulations do not allow Lowest Achievable Emission Rate (LAER) or

offsets unless a source is in (or will impact) a nonattainment area (suggests that LAER or offsets

are imposed by FLM).

Response: FLMs can only recommend, not impose, possible approaches to reduce impacts on

AQRVs. However, even if states are prohibited from requiring LAER or offsets in attainment

areas, states should be able to offer permit applicants the option of installing better controls or

obtaining offsets to avoid denial or permits.

Comment: States cannot comply with a metric unrelated to NAAQS. If the FLMs feel the

secondary NAAQS is inadequate, they should participate in the national NAAQS

development/revision process.

Response: FLAG presents procedures for FLMs to identify air quality impacts and to

recommend remedial action. FLAG is not a regulatory process. Nevertheless, the FLMs have
33

participated in NAAQS development by providing ozone effects information to EPA and

commenting on proposed NAAQS. However, States can adopt a standard that is more stringent

than the NAAQS (for example California Air Quality standards are different than the NAAQS),

and can also adopt a metric that is more suited to plant response, if the State so chooses.

Comment: The following concerns are raised regarding the perception that FLAG is providing

prescriptive regulatory elements for ozone:

1. Establishes threshold values and metrics for determining adverse impacts.

2. Defines visible symptoms below background exposure levels as “damage.”

3. Requires the permitting authority to conduct regional modeling.

4. Establishes experimental ozone exposure protocols for “damage.”

5. Establishes ozone-modeling requirements.

Response:

1. Adverse impact determinations must be based on sound data. Threshold values and

metrics for adverse impacts are from data obtained by scientific experimentation and

available research.

2. Visible symptoms have been defined as “damage” by scientists since the 1960’s and

earlier if they are considered to have negative impacts on aesthetic values. The FLMs

find it inappropriate to re-define definitions long accepted by the scientific

community. The definitions for injury and damage are independent of, and have no

relationship to, ambient concentrations. See references in ozone chapter and literature

cited.

3. FLMs cannot require regional modeling. This authority resides with the State

regulatory agencies. FLMs only recommend impact assessment techniques.

4. FLMs can recommend scientifically sound experimental procedures to determine

vegetation effects.

5. The FLMs suggest ozone modeling be conducted under certain conditions of

expected ozone impact on vegetation. The FLMs do not claim expertise in ozone

modeling, and do not set requirements for ozone modeling.

Comment: FLAG is “penalizing new or modified sources for existing condition.”

Response: The ozone chapter provides guidelines for identifying impacts of ozone on vegetation

in natural ecosystems and recommends remedial action. It does not penalize sources. FLMs can

only recommend protective action and have no authority or intent to penalize sources. Only

regulatory agencies can mandate mitigation for existing or proposed impacts.

Comment: The FLMs may conservatively assume the proposed source would result in

unacceptable impacts, and assume culpability without actual evidence.

Response: The FLMs have a clear mandate to protect AQRVs, and to err on the side of

protecting resources when evaluating impacts of source emissions on AQRVs in Class I areas.

The FLM will recommend remedial action only when there is evidence of an impact

(phytotoxicity present) or concentrations of ozone are at a level that have been shown to cause an

impact.
34

Comment: Any general requirement forcing PSD applicants to conduct ozone studies without

showing compelling evidence that such studies are warranted, is overbearing.

Response: FLMs cannot require or force PSD applicants to conduct ozone studies. Permitting

authority is with the State agencies and/or EPA. The FLAG Report is clear that FLAG actions

are recommendations and that the permitting authority ultimately decides to issue or deny a

permit.

Comment: FLAG is setting an ozone standard for the west, with the burden of addressing ozone

problems falling on new sources.

Response: FLAG provides guidance and does not establish any standards.

Comment: FLMs assume that recommending LAER will reduce or eliminate phytotoxic effects.

FLAG should not assume visible symptoms result from ozone emissions.

Response: There is no text in the FLAG report that says LAER will reduce or eliminate

phytotoxic effects. FLMs do not make these assumptions. FLAG only assumes that additional

ozone from precursors from point sources might cause additional phytotoxic effects. Further, the

FLMs have added text to indicate the lack of a close cause/effect relationship between precursor

emissions and ambient ozone.

Comment: FLAG substitutes their alternative procedure for assessing impact, rather than using

source receptor modeling. FLMs are not free to substitute their own judgment.

Response: FLMs can use their scientifically based judgment to assess ozone impacts on

vegetation, and can recommend remedies based on that assessment.

Comment: FLMs do not have the authority to base their assessment of ozone impacts from a new

source on existing conditions at the Class I area.

Response: The Clean Air Act directs FLMs to assess whether a new source will cause or

contribute to adverse impacts at a Class I area. While it would be preferable to model a source's

contribution to ozone concentrations is a Class I area, as discussed in the FLAG report, singlesource modeling is not an option at this time. Therefore, FLMs will evaluate existing conditions

and determine if it is likely that the new source's emissions would reach the Class I area. If so,

and if phytotoxic ozone concentrations and/or vegetation damage have been documented, then it

is reasonable to assume that the new source will exacerbate existing conditions.

Comment: The FLAG report is a direct attack on the scientific validity of EPA’s secondary

ozone standard. The EPA secondary standard is protective of plant life. FLMs propose to use a

different standard.

Response: FLAG recognizes that an EPA secondary standard exists and that the new 8-hr

standard is more protective of plant life than the 1-hr standard. The FLMs have added text to that
35

effect in the report. The FLAG statement quote that “biologically relevant ozone metrics for

plants cannot be directly related to, nor can they be calculated from, the 8-hour NAAQS for

ozone” is well supported by scientific data. See U.S. EPA (1996) literature citation.

Furthermore, under Section 160 of the Clean Air Act, one of the primary purposes of the PSD

program is to protect public health and welfare from any adverse air pollution effects below the

NAAQS.

Comment: The fact that the FLMs propose to use a different standard than the existing NAAQS

could lead to an FLM recommending against a project that meets the ozone NAAQS but which

in the FLM’s view nevertheless damages plants. FLMs have neither the statutory authority nor

the expertise to set themselves up as alternative air quality regulators.

Response: FLAG cannot and does not propose to use a different NAAQS, nor does it propose to

regulate air quality. FLMs do have the statutory requirement to evaluate air quality impacts on

AQRVs and may recommend remedial action when effects are documented. There is no statutory

requirement to use the NAAQS to evaluate ozone effects on AQRVs.

Comment: FLMs should only consider ozone in a permit review if 1) elevated ozone occurs in

the project area, and 2) the proposed source would add “the missing parameter” for ozone

formation.

Response: FLAG agrees that the FLMs will be concerned if: 1) there are elevated ozone levels

in an area, and 2) the source adds precursors for ozone formation.

4. Use of Passive Ozone Sampling Data

Comment: Passive monitors should be used in remote locations for determining year-to-year

changes in total ozone and for indicating where continuous monitors should be located.

Response: The FLMs agree. On page 82 of the FLAG report regarding passive monitoring data,

it states, “The data are useful for indicating year-to-year changes in total ozone exposure at an

individual site, and for indicating where continuous monitors should be installed.”

Comment: Because passive samplers provide only limited information on ozone exposure,

continuous monitors should be used to calculate W126 and N100 parameters. Only data from

continuous monitors should be used for calculating W126 and N100 metrics.

Response: The FLMs agree. Page 82 of the report also states, “Continuous monitoring is also

necessary to determine the temporal dynamics of ozone exposure to vegetation, and is necessary

to calculate the W126 and N100 parameters.”

Comment: Passive monitors should not be used for assessing vegetation effects. Passive ambient

data have no value in assessing adverse impacts or validating a model.

Response: The FLMs agree. The FLAG report recommends passive monitors to “... give total

exposure loading values for a specified period of time. The data are useful for indicating year-to
36

year changes in total ozone exposure at an individual site and for indicating where continuous

monitors should be installed. However, FLMs recognize the limitation of passive samplers in

relating ozone exposure to plant response” (see page 82 of the FLAG report). FLAG does not

recommend assessing adverse impacts using passive samplers. In fact, FLAG specifically

cautions against it.

5. Experimental Fumigations

Comment: FLAG should not recommend unrealistic experimental exposures such as 1.5 and 2.0

times ambient. NCLAN protocol exposures of 1.5 and 2.0 times ambient are unrealistic and

should not be used for experimental exposures. FLAG should use realistic exposures to develop

quantitative relationships between growth loss and ozone exposure.

Response: The FLMs has revised the FLAG report to indicate plants should be exposed to

concentrations simulating increased levels of ambient ozone that might occur above current

ambient levels in the future.

Comment: Agencies should join forces to construct and operate experimental facilities, and

eastern facilities might not be appropriate for western species and vice versa.

Response: The FLMs agree. The final FLAG report retains the draft report language that stated,

“...it would be appropriate for agencies to join resources and develop regional fumigation

facilities” and “...ambient conditions at an eastern facility might not be appropriate for western

species and vice versa.” (see page 81 of the final report).

Comment: Experimental fumigations should focus on growth loss measurements.

Response: The FLMs agree that growth loss is important; but injury symptoms can also be

monitored and should not be ignored if they occur in these experiments. Many FLMs are as

concerned with injury as a negative aesthetic impact as they are with growth loss. FLAG

recommends experimental fumigations to “verify ozone-induced foliar injury symptoms

(observed) in the field" (see page 81 of the FLAG report).

Comment: Growth response data were from experiments grown under optimum conditions, and

may not represent the real world.

Response: The FLMs agree. Further, FLAG points out that conditions for production of defenses

against ozone impact are also optimum under these conditions.

Comment: Experimental chamber work should not be used for determining sensitivity

classifications.

Response: The FLAG report does not suggest that chamber fumigations be used for determining

sensitivity classification. FLAG recommends chamber fumigations “to verify ozone-induced

foliar injury symptoms (observed) in the field...” (see page 81).
37

6. Uncertainty Factor

Comment: FLMs should include uncertainty factors with the growth loss predictions and in

growth response data.

Response: Uncertainty data are unavailable to the FLM at this time. The FLMs agree these data

should be included where available.

7. Background Ozone Levels

Comment: The FLAG report does not address background ozone levels. The report does not

address the effect of natural background levels of ozone on AQRV impact assessment.

Response. The FLMs have added text discussing background ozone. The FLMs are concerned

about impact of additional ozone on vegetation independent of background ozone concentrations.

Comment: Delete Appendix 3.B, because oxidant stipple injury can occur at ambient

concentrations that are background. The information cannot be used for assessing damage and

relating the information to a mathematical ozone exposure relationship.

Response: FLAG recognizes that oxidant stipple injury can occur at background ambient

concentrations. Injury from natural sources does not negate FLM concerns about additional

ozone impacts on vegetation from anthropogenic sources. Even though background ozone might

cause injury, FLMs are concerned about impact of additional ozone on sensitive species. Text

has been added to the report to indicate the recognition of the weak mathematical relationship

between ozone exposure and plant response.

Comment: FLAG should not use phytotoxic effects shown to occur at background ozone

concentrations as an indicator of damage. Science does not support the assumption that oxidant

stipple injury can be damage. FLAG should not assume visible symptoms constitute damage

since EPA recognized that many ozone effects on vegetation are not attributable to

anthropogenic sources, but rather arise from natural processes.

Response: Damage has been specifically defined in the scientific literature for more than 40

years to include a negative impact on aesthetic value. Most FLMs have determined that foliar

injury is a negative aesthetic value. Thus, considering visible symptoms to be damage does not

conflict with the classic definitions of injury and damage. See the definitions of injury and

damage in the text and their citations.

8. W126/N100 Concerns

Comment: The basis and relevancy of the W126 metric needs to be provided.

Response: Section D.3.c. of the FLAG report (pages 76-78) provides a detailed discussion as to

why the W126 was selected.
38

Comment: The N100 has no averaging time.

Response: The N100 is the number of hours of ozone concentration above 100 ppb. It is a

cumulative parameter and cannot be averaged. The definition of N100 in the text has been

clarified.

Comment: Data tables for growth and injury losses are not available for many species,

preventing assessment of adverse impacts.

Response: The FLMs recognize that data are unavailable for many species, but this does not

negate the use of the table for those species for which information is available.

Comment: FLAG should use both the W126 and the N100 together for growth response. The

W126 must be tightly coupled with the N100 for estimates of growth loss. Coupling the W126

and N100 values in both experimental and ambient exposures is necessary if experimental results

are used to predict growth losses under ambient conditions.

Response: The FLAG report does not recommend using either the W126 or the N100 alone for

growth response, but included both in the Table of response.

Comment: The W126 and N100 are not threshold values; Table O-1 should be eliminated from

the report.

Response: The FLMs agree that these values are not thresholds, and did not call them threshold

values in the table. The FLMs have chosen to retain the table in the FLAG report. However, to

avoid confusion, text has been added to specifically state that injury may occur at exposure levels

lower than those listed in the table.

Comment: Additional effort should be expended to develop exposure response relationships for

the W126 and N100 for predicting growth loss.

Response: The FLMs agrees additional effort should be expended and additional data are needed.

Comment: FLAG shouldn't use the N100 metric because vegetation effects occur well below this

level.

Response: The FLMs have revised the FLAG report to acknowledge that foliar injury occurs

well below N100. However, the N100 was closely coupled with the W126 for experimental

fumigations that determined growth loss, and is thus included in the exposure/response

relationship. FLAG does not recommend that the N100 be used alone to indicate plant response.

Comment: Using the N100 is not justified. Tables O-1 and O-2 are misleading because they

imply causality when only an association has been demonstrated. There are no caveats to the data

regarding experimental condition. In order to establish critical levels there should be additional

studies performed across environments.
39

Response: Using the N100 is closely associated with the W126. The Tables simply show

experimental exposures where injury or growth effects occurred. The data in the tables are valid.

The FLMs have added a caveat to the text that results may differ under different experimental

conditions.

9. 24-hr Time Period

Comment: Using the 24-hr time period is unjustified. The supporting reference is trivial with

little real substance, and should not be used in the chapter. FLAG needs a connection between

species found in FLM areas and those showing nighttime conductance identified in the

Musselman and Minnick paper before a 24-hr time period for the W126 metric can be used.

Response: The peer reviewed Musselman and Minnick paper provides numerous citations

documenting nocturnal stomatal conductance of plant species, and indicates that most species do

not completely close their stomata at night. Further, it documents decreased plant defenses

against ozone injury at night. Thus, the FLMs believe that using the 24-hr time period for the

W126 is justified. One commenter suggests that citations indicating open stomata are not as

valuable as those showing stomatal conductance. The FLMs agree that “open stomata” is not the

same as “conductance.” The commenter is reminded that neither open stomata nor stomatal

conductance prove ozone uptake. But since science generally recognizes that ozone

concentration is zero or near zero inside leaf tissue, an open pathway and an ozone gradient

between ambient air and leaf tissue strongly suggest ozone uptake.

10. Miscellaneous Comments

Comment: Suggest FLAG change “sensitive species” to “sensitive genotypes.”

Response: The FLMs agree, but removing sensitive genotypes could well eliminate certain

sensitive species.

Comment: FLAG should state that field staff must be experienced and tested in data collection

for field assessment of injury.

Response: The FLMs agrees and have added a statement to that effect in the FLAG report.

Comment: Information in Appendix 3.A is not documented in the literature.

Response: The FLMs have added a statement in the Appendix that this information was

determined by scientists each having more that 20 years of experience identifying oxidant stipple

injury in the field.

Comment: Why the concern about foliar injury of invasive species such as tree-of-heaven?

Response: These species can be used as bioindicators for injury. They may occur in FLM

managed areas.
40

Comment: There are inconsistencies in Appendix 3.B. For example, Eastern red bud is listed for

Okefenokee, but not in other Class I areas where it is currently found. Red spruce listed as

sensitive in Dolly Sods, but it is not sensitive.

Response: The FLMs have indicated that the species listing for each Class I area is not complete,

but a work in progress. Text in the FLAG states, “Unfortunately, AQRV identification is limited

by incomplete species inventories...” (see page 78). The FLMs welcome information on the

occurrence of species for specific areas. The FLMs agree on red spruce and have removed it

from the list for Dolly Sods.

Comment: FLAG should solicit input from the applicant regarding likely impacts. FLAG needs

to involve stakeholders and quantify economic impacts.

Response: The FLMs will continue to work with applicants in any NSR permit analysis.

Economic analyses are not required for FLM evaluation of ozone impacts on vegetation and

recommended remedies.

Comment: FLMs need to pay more attention to human health.

Response: The FLAG report indicates that plants are more sensitive to ozone than humans (page

74), and has chosen to focus on the most sensitive receptor, plants. It is EPA's responsibility to

set HAAQS to protect human health.

Comment: Regarding the flow chart, "If vegetation effects are unknown the FLM is unlikely to

object to a permit. There is concern for inaction where an impact is unknown.

Response: It is difficult for the FLMs to recommend a remedial action without specific data to

support a negative impact.

Comment: It is not clear why the SUM06 metric wasn’t used.

Response: Reasons for selecting the W126 were detailed in the ozone chapter in section D.3.c,

pages 76-78. The EPA dropped their support for the use of a secondary standard based on

SUM06. It should be noted that the SUM06 considers ozone values less than 60 ppb as not

important in plant response, where the W126 includes values below 60 ppb.

Comment: Substitute “exposure” for “concentration” in the second paragraph of the Introduction.

The last sentence is misleading in implying that the EPA has not taken any action to provide

increased protection for vegetation.

Response: The FLMs have made changes in the final report to address these issues.

Comment: Encourages FLM effort to gather information on AQRVs.

Response: The FLMs agree, but have limited resources to gather such information.
41

Comment: The decision chart proposed for potential ozone effects bears no correlation to any

effects from a proposed new source. Recommend that the ozone section be removed because of

the difficulty of measuring ozone impacts and that sources causing such impacts would also

present visibility and deposition concerns.

Response: The decision chart is a guideline for FLMs to determine current impact of ozone on

vegetation and to recommend FLM response based on current impacts. The FLMs consider the

procedures described in the decision chart to be an appropriate method for identifying ozone

impacts and recommending remedial action for protection from proposed new sources, and the

ozone chapter should not be removed. The FLMs recognize that visibility and deposition effects

may be easier to identify and quantify, but the FLMs place equal value on protecting all AQRVs

from ozone, deposition, and visibility impacts.
42

E. RESPONSE TO DEPOSITION COMMENTS

This section provides FLM responses to public comments received on the deposition chapter of

the draft FLAG Phase I report.

1. Comment: Deposition critical loads are not available in the report and should be included in

an appendix.

Response: As described in the Introduction of the Deposition Chapter (page 117 of the FLAG

report), the FLMs have agreed that site-specific air quality related values (AQRV) and critical

load information would be maintained on FLM web sites, rather than included in the FLAG

report. In this way, information can be updated and the most recent versions made quickly

available to the public. Some of this information is already available on web sites referenced in

the report, and the FLMs are committed to entering remaining available information as soon as

possible.

2. Comment: The report refers to web sites where deposition critical loads should be available.

However, the information is not always available on the web sites. Web sites are incomplete.

Response: As noted above, some critical load information is now available on FLM web sites, as

referenced in the FLAG report. However, as discussed in the report, establishing critical loads is

a complex process, requiring information that is not currently available for many FLM areas. As

discussed in the Introduction of the Deposition Chapter, the Deposition subgroup recognizes that

developing and refining site-specific critical load values for all FLM areas are crucial for AQRV

protection. However, because of the complexity of this undertaking, and the lack of information

for many areas, it was deferred to Phase II of FLAG. PSD permit applicants are advised

throughout the FLAG report to consult with the FLM on AQRV analyses to ensure that the

applicant obtains the most recent information on AQRVs and critical loads.

3. Comment: Deposition monitoring data are not given in the report. It should be provided in

summary form.

Response: The “Available Deposition Monitoring Data” section of the chapter (page 134) notes

that the FLMs have agreed that it is preferable to obtain wet and dry deposition data from the

National Atmospheric Deposition Program (NADP) and Clean Air Status and Trends Network

(CASTNet) web sites, rather than summarizing deposition data in the FLAG report. In this way,

the entire data record for a site, including the most recent data, can be easily accessed by FLMs

and the public. This is useful for estimating current deposition rates. For example, in the section

“Estimation of Current and Future Deposition Rates” (page 139), the applicant is advised to

estimate deposition rates using all years with complete data records. Summary values developed

for the FLAG report would be gradually outdated, as new data become available both from

existing monitors and newly established monitors.

4. Comment: Critical loads should be established through a public review process rather than ad

hoc collaborative processes. Public input is needed to establish critical loads.
43

Response: The FLMs appreciate the participation of the public in the AQRV identification

process and the establishment of critical loads. Section C.1 on page eight of the FLAG report

states, “Public involvement in this process is necessary and will be accomplished through

participation in the land management planning process or reply to an announcement in the

Federal Register.”

However, FLMs agree that they have the primary responsibility to identify AQRVs and set

critical loads. Congress charged the FLM and the Federal officials with direct responsibility for

management of Class I lands (e.g., Park Superintendent, Refuge Manager, or Forest Supervisor)

with an affirmative responsibility under Section 165 of the Clean Air Act to protect and enhance

the AQRVs of Class I areas from the adverse effects of air pollution. Further, Congress directed

the FLM to “assume an aggressive role in protecting the air quality related values of land areas

under their jurisdiction. In cases of doubt the land manager should err on the side of protecting

the air quality-related values for future generations.” (Senate Report No. 95-127, 95th Congress,

1st Session, 1977)

The FLMs interpret this assignment as a responsibility to identify AQRVs and establish critical

loads, when appropriate, to protect those AQRVs, and to take a conservative approach when

doing this.

Identifying AQRVs and establishing critical loads have been based on information from the

peer-reviewed scientific literature. In cases where site-specific peer-reviewed literature is not

available, the FLM may rely on best available information and expert judgement, guided by

Congress’ direction to “err on the side of protecting air quality-related values for future

generations.”

5. Comment: FLAG should recognize the complexity of deposition analyses. FLAG does not

provide clear guidance for deposition modeling.

Response: The Deposition subgroup recognizes that deposition analyses are very complex.

Many physical, chemical, meteorological, and biological processes interact to determine

deposition rates of pollutants onto vegetation, soils, water, and other surfaces. Deposition

models attempt to characterize these complex processes in order to estimate deposition rates.

The FLAG report advises using guidance for deposition modeling developed by the Interagency

Workgroup for Air Quality Modeling (IWAQM). A permit applicant can be reasonably expected

to run the recommended model and derive deposition estimates without undue hardship, while

providing the FLM with the information necessary for evaluating potential impacts to AQRVs.

For their part, the FLMs are often required to review and respond to permit applications and

modeling analyses for new or modified sources within a short time frame and the standardized

IWAQM guidance facilitates this process.

6. Comment: FLAG should recognize the unavailability of adequate monitoring methods. More

deposition monitoring is needed.

Response: The Final FLAG Deposition Chapter has expanded its discussion (in Section 4.f) on

the limitations of deposition monitoring methods, particularly for dry deposition and deposition
44

from clouds, fog, and snow. The report states that even wet deposition may not be well

characterized at an area with large elevation differences because deposition can increase with

elevation at many areas. Data from a deposition sampler at a low elevation may be very different

from data at higher elevations. Modeling may be used to estimate deposition in these situations.

As discussed in the chapter, the FLM recognizes that for areas with significant cloud, fog, or

snow deposition, deposition monitoring is difficult and data for very few areas are available. In

some areas, deposition from cloud water and fog may equal or exceed deposition from rainwater.

Applicants are advised to consult with the FLM to determine how to characterize deposition for

these areas.

The chapter also recognizes that dry deposition measurements are difficult to make. Extensive

site-specific information is needed in order to model deposition rates from dry gas and particle

concentrations. Various dry deposition measurement methods are described in the chapter and

their suitability for certain locations discussed.

Regardless of the limitations of available deposition monitoring methods, the FLM must obtain

estimates of deposition in order to evaluate potential effects to resources. Therefore, the FLAG

report provides guidance to applicants for estimating deposition based on readily accessible

monitoring data, recognizing that these data have their limitations. As noted above, applicants

are always advised to consult with the FLM so that the most current and appropriate data may be

used.

7. Comment: Deposition limits (i.e., critical loads) are extremely difficult to establish. Critical

load information should be based on direct studies in Class I areas.

Response: The FLAG report recognizes that critical loads are difficult to establish. The

Deposition Chapter states that “FLMs agree that a critical load should protect the most sensitive

AQRVs within each FLM area and should be based on the best science available.” It is a

challenge to identify these most sensitive AQRVs and establish critical loads for their protection.

FLMs are guided by Congress, who gave the FLM an affirmative responsibility to protect

AQRVs and, when in doubt, to err on the side of protecting the resource. Therefore, the FLM

must establish critical loads to protect AQRVs even when information is incomplete, using the

best available science.

Establishing critical loads depends on the large body of scientific literature on AQRVs. In

addition, considerable site-specific AQRV information is needed for this task, requiring direct

studies in the FLM area. Because of temporal differences in AQRV sensitivities (as well as

spatial differences), AQRVs must be monitored over the long-term to discern these differences.

8. Comment: FLAG fails to clarify the rationale for establishing critical loads and does not make

supporting documents available.

Response: The Introduction to the Deposition Chapter notes that Phase I tasks would include the

summarization of information currently available about deposition and its effects on FLM areas.

Critical load values, where available from previous FLM guidance documents, would be
45

referenced. FLMs agreed that site-specific AQRV and critical load information would be

maintained on FLM web sites, rather than included in the Phase I report.

In the section, “Critical Loads in FLM Areas,” the chapter describes the efforts of the National

Park Service and the Forest Service to establish critical loads through regional reviews and

regional and national workshops. The section references the Regional Review documents and

Proceedings Documents from the regional and national workshops. These documents provide

the rationale for establishing critical loads and are listed in Appendix H of the report. Because of

their length, these documents were not directly included in the FLAG report. They are available

through the appropriate FLM.

9. Comment: The public needs access to AQUIMS to evaluate the merits of this database.

Response: The Deposition Chapter has been revised to note that AQUIMS (Air Quality

Information Management System), developed by the FWS and NPS, is now known as Synthesis.

During the course of the development of AQUIMS, resource managers recognized that it was a

valuable tool for managing resources other than air. As its use broadened, the name was changed

to Synthesis. Geological and water quality data, as well as air quality data, now resides in

Synthesis. Synthesis is still under development and will be available through the NPS web site

at:

http://www.nature.nps.gov/ard

10. Comment: Deposition impacts are likely to be understated because cloud water impaction is

not addressed.

Response: FLMs recognize that, in some areas, deposition from cloudwater and fog may be very

significant. The “Wet Deposition” section of the chapter discusses the importance of cloudwater

and fog deposition. Cloud water is generally more acidic than rain water and deposition from

clouds may equal or exceed deposition from rain water. Deposition estimates that do not include

the contribution from clouds and fog may result in underestimates of wet deposition. The section

describes monitoring and modeling efforts to quantify cloud water and fog deposition.

While recognizing the importance of including cloud water and fog contributions to deposition,

the FLM is often faced with a lack of information regarding such contributions. In the section,

“Estimation of Current and Future Deposition Rates,” applicants are advised to consult with the

FLM when addressing impacts in high-elevation sites to determine if deposition from

cloudwater, fog, dew, or snow should be considered.

11. Comment: FLAG fails to address impacts of fires and mobile sources.

Response: The Deposition Chapter provides guidance to permit applicants wishing to construct

or modify sources of air pollution near FLM areas. This guidance may also be applied to NEPA

analysis, for example, for a proposed fire management plan or a proposed highway. The

influence of existing fire activity and mobile sources is reflected in background deposition

measurements.
46

12. Comment: FLAG sets different and more stringent standards than those developed by EPA.

Response: FLAG does not set standards. Rather, FLAG has provided guidance, at the request of

EPA, States, and industry, for protecting AQRVs. EPA, while having the regulatory authority to

set standards, has not done so for deposition.

FLMs have established critical load guidelines for certain FLM areas in response to Congress’

mandate to the FLM to protect AQRVs and to err on the side of protecting the resource. However,

these are guidelines, not standards.

13. Comment: It is recommended that FLAG build on Europe’s advances on establishing critical

loads.

Response: The FLAG report discusses the work done in Europe and Canada on establishing

critical loads in the section “Determining Critical Loads.” The FLMs have considered the

scientific literature from Europe in establishing critical loads in FLM areas. This literature is

referenced in the FLM Regional Reviews and Proceedings Documents from regional and

national workshops on AQRVs (Appendix H).

14. Comment: Critical loads should be updated based on 5-yr reviews.

Response: In the chapter Introduction, the report notes that critical loads previously established

should be reviewed and revised, as necessary. The FLM recognizes that the best available

information should be used to refine critical loads.

15. Comment: Assumption that dry equals wet deposition may be inappropriate in many areas.

Response: The section “Dry Deposition” discusses the limitations of making the assumption that

dry equals wet deposition. This assumption may result in over- or under-estimates of total

deposition. However, for some areas it may be the best available estimate. The discussion on

dry deposition includes various methods for dry deposition measurements, as well as modeling

estimates.

16. Comment: FLM needs to be more proactive in areas where impacts are unknown, e.g., by

requesting applicant perform pre-construction and post-construction monitoring.

Response: Figure D-1 in the Deposition Chapter notes that for areas where effects are unknown,

or if the proposed source may cause or contribute to an adverse effect, the FLM may recommend

deposition and deposition effects monitoring and/or research.
1

SUMMARY OF PUBLIC COMMENTS ON DRAFT FLAG PHASE I REPORT

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

1 Colorado Assoc.

of Commerce and

Industry (Dennis

Arfmann)

Clarify that FLAG is only

guidance and not binding on

any permitting authority; "err

on side of protecting AQRVs"

quote is not indicative of

Congress' true intent; should

clearly delineate which

portions relate to PSD permits

for Class I areas vs. Class II or

"beyond NSR" situations;

guidance exceeds statutory

authority---no basis to require

cumulative impacts on

AQRVs, cites proposed

facility "will have" language

in Sec. 165; no basis for

LAER, offsets, or enhance

technology in PSD context;

FLMs attempt to coerce

research funding through the

permitting process is not

appropriate; the stringent

analysis and onerous

recommendations are arbitrary

in light of impacts from FLM

activities--e.g., fire and

mobile emissions.

Using very low visibility

thresholds and comparing

to arbitrarily set

background levels is

unsupportable and

arbitrary; cumulative

impact analysis described

in the report contains many

technical flaws, e.g.,

inconsistencies with

IWAQM guidance,

emission decreases should

also be included; visibility

modeling, depending on

whether the source is < or >

50 km is inconsistent (24-hr

vs. hourly averages,

inconsistencies w.r.t.

Regional Haze Rule).

Deposition section is nearly

impossible to analyze when

websites for deposition

monitoring data and critical

loads are unavailable; until

such data are available,

FLMs should withdraw the

deposition sections of the

report; no basis for

assuming dry = wet

deposition; fails to address

deposition effects of FLM

activities, i.e., fire and

mobile sources are

significant contributors to

sulfate and nitrate

deposition and must be

addressed.

The decision chart

proposed for potential

ozone effects bears no

correlation to any

effects from a proposed

new or modified

source; given problems

with assessing

individual source

impacts, recommend

that FLAG rely on

deposition and/or

visibility concerns and

remove the ozone

section from the report

until better individual

source assessment

methods are available.

2 Steel Manufact.

Assoc. (Thomas

Danjezek)

Supports the efforts of FLAG;

agrees with FLAG that there

needs to be a consistent,

predictable, and objective

FLMs should defer to

EPA's regional haze

regulations as a means of

fulfilling their visibility
2

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

approach to identify and

assess impacts on AQRVs;

FLMs should not only focus

on PSD sources but should

also work with States to

develop SIPs targeted at

minor and grandfathered

source reductions; the final

report should make clear that

the permitting authority has

the ultimate responsibility to

make the BACT

determination; supports

emissions offsets, but FLAG

must clarify how such a

program would be

administered.

protection obligations.

3 Arizona DEQ

(Nancy Wrona)

Commends FLMs on FLAG

effort; What is schedule for

Phase II? What support exists

for continuation of the

project? Suggests FLAG

consider coordinating with

universities to promote

necessary research (e.g.,

Northern Arizona Univ. is

equipped to perform ozoneinjury research); in addition to

"sound smoke management

practices", FLMs must

conduct very careful

prescribed fires in

consultation with State air

Do FLMs anticipate

moving to Class I-area

specific definitions of

natural conditions? FLMs

should support monitoring

and using NO2 data in

visibility analyses; the light

extinction for NO2 should

be included in the formulas

and calculations;

combining 1-hr RH values

into a 24-hr average is

problematic--it is not

representative of

atmospheric conditions,

given the diurnal range of

Unlike visibility, there are

no deposition screening

values to allow for a quick

evaluation of potential

impacts; ADEQ was unable

to review the referenced

websites and recommends

that this information be

included in the FLAG

report as an appendix.

There actually are

several atmospheric

models that have the

capability of estimating

changes in O3

concentrations from a

single source (e.g.,

UAM, Models3,

SAQM-AERO), but

model validation and

adequate emission

inventories would be

needed before applying

these models to rural

Class I areas.
3

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

regulators. RH across AZ; perhaps it

would be better to process

RH data in the model as 1-

hr averages to calculate

sulfate and nitrate

formation and then

calculate the 24-hr average

extinction; given the

diurnal variation of RH,

classification schemes

should include elevation

and meteorological season

as a minimum; given the

elevation range of 2,000 to

11,000 for AZ Class I

areas, the Reference Level

Values can not be the same-

--they should be specific to

the area in question.

4 National

Environmental

Development

Assoc./Clean Air

Reg. Proj. (Leslie

Ritts/Ellen Siegler)

Would welcome opportunity

to meet w/FLMs to discuss

Class I issues; definition of

AQRVs and the criteria for

identifying them need to be

sharpened; a clearer process

for identifying "adverse

impact" is needed--better

technical support for listed

benchmarks and additional

public comment; report must

be made more consistent with

the CAA's provisions

regarding relative

Essential to accurately

estimate natural conditions-

-effects from fire should

not be expected to be

mitigated by PSD sources;

questions the basis for

chosen thresholds--further

analysis is needed; don't

rely on PSD program to

mitigate problems caused

by existing sources.

Deposition sections are

weak and should be

withdrawn and deferred to

the Phase II report, once

data and methodological

issues have been resolved;

FLMs should establish de

minimis values for all

effects not just visibility;

can't penalize new sources

if existing sources are

causing critical loads to be

exceeded; websites and

AQRV lists are incomplete;

Ozone sections are

weak and should be

withdrawn and deferred

to the Phase II report,

once data and

methodological issues

have been resolved;

FLMs should establish

de minimis values for

all effects not just

visibility; passive

monitoring data is of

no value in assessing

potential impacts from
4

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

responsibilities of the FLMs,

permitting authorities, and

permittees (i.e., burden

shifting from FLM to the

applicant when no increment

is violated); focusing on

nonattainment areas and

seeking SIP revisions is a

waste of the FLMs time--they

should focus on their own

responsibilities; FLMs should

defer to permitting authority

regarding data and modeling

and BACT issues; it is

troublesome that the FLMs

refuse to prioritize AQRVs;

"current" and "existing"

conditions should not be

addressed in the context of

PSD permitting.

critical loads should be

established through a public

review process rather than

ad hoc "collaborative"

processes.

a new source.

5 Department of

Energy (Bill

Hochheiser)

The analysis required

doesn't seem to take into

account the kind of

operations represented by

oil and gas development--

many distributed small

sources whereas

CALPUFF/CALMET

model is designed to

address a small number of

large sources; using broad

temporal and geographic

averages for both natural
5

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

conditions, RH, and impact

modeling fails to account

for wide variations in

conditions; the

recommended methodology

should include comparison

of modeling results with

monitoring data; the

visibility discussion should

be broadened to include

other scientists with various

expertise.

6 Oregon DEQ (Pat

Hanrahan)

Current "very large sources"

>100 km language appears to

only consider sources with

emissions of tens of

thousands of TPY--

recommend FLAG expand the

distance criteria from 100 km

to 200 km.

The same decision

thresholds should be used

for both screening and

refined modeling; drop the

0.4% criteria until the

consequences of this level

are evaluated further;

provide examples of how

"magnitude, frequency,

duration, and other factors"

could be considered; need

to clarify that "Estimates of

Natural Conditions" does

not consider smoke for

wildfires and/or prescribed

burning; having seasonal

average background data

would improve modeling

applications.

This section is very weak

and needs to be more

definitive--should list

critical loads for Class I

areas, identify areas that

exceed critical loads, and

include significant impact

criteria for single source

impacts on those areas;

recommend that FLAG

summarize the available

deposition data in report

tables.

Although the focus is

on NOx reductions in

NOx limited areas,

recommend that

language be added to

recognize that ozone

impacts also result

from VOC emissions.

7 WESTAR (Dan

Johnson)

Very similar to Oregon

DEQ above.

See Oregon DEQ above. See Oregon DEQ

above.
6

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

8 Alabama DEM

(Ronald Gore)

The information provided is

largely procedural with little

technical justification for the

action levels or critical values

recommended.

FLAG efforts seem

duplicative with efforts of

the Regional Haze Rule to

attain the same goals; what

is the regulatory or

scientific basis for

suggested levels of concern

and analysis/decision

thresholds? These levels

seem to be arbitrarily

selected; consider seasonal

averages or longer, rather

than 24-hr averages to

account for wind/weather

patterns.

The absence of single

source model for ozone

impacts suggests it is

premature to restrict

PSD permits on the

basis of ozone impacts

on vegetation; States

cannot comply with

other metrics unrelated

to the NAAQS; if the

FLMs feel the

secondary ozone

NAAQS is inadequate

to protect public

welfare, they should

participate in the

national NAAQS

development/revision

process; ADEM

regulations to not allow

LAER or offsets unless

a source is in (or will

impact) a

nonattainment area.

9 Colorado Utilities

Coalition for Clean

Air (Christine

Kadlub)

The FLAG document

proposes a framework for

NSR that is inconsistent with

Section 165 of the CAA--

shifts burden of proof to

applicant when increment not

violated, can't require new

source to assess cumulative

impacts or Class II impacts;

Fire emissions on federal

lands are not adequately

addressed in visibility

discussion.

Fire emissions on

federal lands are not

adequately addressed in

the ozone discussion.
7

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

FLAG report is a legislative

rule that must comply with the

procedural safeguards of the

Administrative Procedure Act;

FLAG is not consistent with

federal authority under the

Property Clause of the federal

Constitution because the

FLMs are not authorized to

regulate non-federal property;

FLMs must assess potential

economic consequences

associated with implementing

FLAG recommendations; Key

information is missing from

the FLAG report on which the

public cannot comment; the

FLAG process places a

disproportionate burden on

new or modified sources in

the western U.S.

10 North Dakota

Dept. of Health

(Jeffrey Burgess)

Recommend removing the

ambiguities of "large sources

beyond 100 km" by requiring

notification of all

new/modified sources within

300 km; what is the basis for

requiring States to revise their

SIP to eliminate increment

violations even though the

FLM certified no adverse

impacts for a new source?

Suggested editorial changes

on pages 6 and 32;

"cumulative analysis" in

ozone and deposition

sections appears to imply

total impact, including

baseline sources, whereas

in visibility section it seems

to exclude baseline sources-

-the omission of the impact

of baseline sources in the

FLAG visibility guidance

Recommend that this

section include specific

critical load and existing

levels of wet and dry

deposition, rather than

referring to websites.
8

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

does not make sense,

especially if a baseline

source is already creating

considerable visibility

degradation.

11 Alaska DEC (Tom

Chapple)

Periodic increment

consumption SIP revisions

should not be required, but if

they are it should be every 10

years, not every 5 years.

FLMs should carefully

manage prescribed fires to

minimize visibility and air

quality impacts; question

the use of PLUVUE II,

especially at Alaska altitude

(cites Healy analysis and

associated problems).

References lack of data

discussed in WESTAR

comments; mentions

"anomalous behavior" in

ISCST3's deposition

algorithm; recognizes that

CALPUFF deposition

algorithm works but

CALPUFF is currently a

non-guideline model.

Alaska is not aware of

any ozone problems in

their State; they object

to any general

requirement for PSD

applicants to conduct

ozone studies without

showing compelling

evidence that such

studies are warranted.

12 Utah Governor's

Office of Planning

and Budget (Brad

Barber)

Since the FLAG

recommendations could affect

States much the same as new

NAAQS, FLAG should

undergo a similar scientific

review and public comment

process; how would any postconstruction monitoring data

affect the new source if high

levels were monitored?

Use Delta E = 2 for both

refined and screening

plume analyses; can they

assume no plume analysis

required for sources >50

km from a Class I area?

They do not agree that use

of CALPUFF in the most

appropriate approach to

address far-field haze

impacts because of the high

cost and limited technical

expertise to run the models-

-recommend a regional

scale CALPUFF modeling

system be developed and

administered by the FLMs;

0.4% level is too restrictive;

The FLAG report is

essentially setting an

O3 standard for the

west, with the burden

of addressing O3

problems falling on the

new sources; the report

should address

background and

"natural" ozone levels;
9

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

what is the FLMs intent

regarding Integral Vistas?

13 Oglethorpe Power

Corp. (Graham

Holden)

FLAG should clarify that the

States, not the FLMs, have the

statutory authority to make a

final determination that a

source will have an adverse

impact; the CAA does not

require cumulative "adverse

impact" analyses (cites source

"will have an adverse impact"

(not "cause or contribute to")

language in Section 165);

FLAG shifts the burden of

demonstrating AQRV impacts

from the FLM to the applicant

when no increment is

violated; FLAG report does

not add needed certainty to

new source permitting; FLAG

report establishes legal

standards for a successful

permit and as such is a formal

rule subject to the

Administrative Procedures

Act; FLMs must assess

potential economic

consequences associated with

FLAG implementation.

FLAG does not justify its

threshold levels

14 Western Regional

Council (Bob

Wood)

FLAG recommendations

would usurp state authority

and exceed FLM authority

given them in the CAA by

Visibility thresholds are

arbitrary and can neither be

detected or measured; the

determination of "natural
10

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

establishing standards that are

more stringent than NAAQS;

the new FLAG standards

would eliminate nearly all

manmade activities near Class

I areas; FLAG shifts burden

of proof from FLM to

applicant when increment not

exceeded; no basis to require

cumulative impact analyses

(source "will have" language

in CAA); FLAG does not

adequately assess impacts of

fire and mobile emissions;

AQRV is not clearly defined

and appears to be a moving

target; FLAG should not

expand their review to include

Class II areas or BART

reviews for existing sources;

FLAG report is a substantive

rule that should meet

Administrative Procedure Act

requirements and include an

economic impact analysis;

key FLAG information has

not been made available to the

public; FLAG report was

done by the FLMs behind

closed doors and did not have

stakeholder involvement.

conditions" is extremely

subjective and arbitrary,

does not include fire, and is

not based upon sound

science.

15 ASARCO

(Krishna

FLAG report is a substantive

rule that should meet

FLAG prescribes using

modeling techniques that

FLAG should recognize the

complexity of deposition

FLAG's view of ozone

formation chemistry is
11

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

Parameswaran) Administrative Procedure Act

requirements and include an

economic impact analysis;

FLMs should broaden the

FLAG process to be a more

participatory stakeholder

process; FLAG attempts to

expand FLM authority from

evaluating new sources

impacts on Class I areas

(shifts burden of proof to

applicant when increment not

violated, requires cumulative

analyses when CAA requires

only analysis of the impacts

that an individual source "will

have" on AQRVs, looks at

Class II areas); FLAG process

would interfere with federalstate relationships established

by the CAA; FLAG

diminishes predictability for

certain permitting analyses.

are inappropriate or that

yield unreliable results;

FLAG establishes arbitrary

visibility thresholds; FLAG

provides inadequate

guidance for assessing

cumulative visibility

impacts; FLAG

inappropriately bases

determination of potential

impacts on changes to

natural conditions;

thresholds for refined and

screening plume analyses

should be the same.

analyses and the

unavailability of adequate

monitoring methods;

deposition limits (i.e.,

critical loads) are extremely

difficult to establish; FLAG

should more thoroughly

develop its discussion of

baseline deposition data;

FLAG does not provide

clear guidance for

deposition modeling;

ASARCO agrees with

WEST Associates

recommendations.

overly simplistic;

FLAG should not use

phytotoxic effects

known to occur at

exposure

concentrations within

the range of

background O3

concentrations as an

indicator of vegetation

damage; both the W126

and N100 values must

be used together to

estimate vegetation

growth loss; FLMs

should collect ambient

O3 monitoring data;

FLAG should revise its

criteria for assessing

damage to vegetation

resulting from O3

exposure.

16 Arizona Chamber

of Commerce

(Amy Porter)

FLAG report is a substantive

rule that should meet

Administrative Procedure Act

requirements and include an

economic impact analysis;

FLAG must include

stakeholder involvement and

peer review of technical

material; FLAG attempts to

expand FLM authority under

Cumulative analysis should

take into account emission

decreases as well as

increases; visibility

thresholds are overly strict;

visibility approach is

inconsistent with the

Regional Haze Rule.

FLAG fails to clarify the

rationale for establishing

critical loads and does not

make supporting

documents available; a

LAC of 0% is unrealistic;

more information is needed

regarding deposition

models; FLAG should

provide more substantial

FLAG should not

assume that visible

symptoms (e.g.,

oxidant stipple)

constitute O3

"damage"; both the

W126 and N100 values

must be used together

to estimate vegetation

growth loss; FLAG's
12

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

the CAA (shifts burden of

proof to applicant when

increment not violated,

requires cumulative analyses

when CAA requires only

analysis of the impacts that an

individual source "will have"

on AQRVs, looks at Class II

areas); PSD regulations do not

require that permits be denied

based solely on the FLM's

visibility analysis--permitting

authority has discretion to

balance several factors;

uncertainty does not represent

an adverse impact finding.

methodology for estimating

baseline deposition levels.

recommended exposure

protocol is

inappropriate because it

result in higher hourly

average concentrations.

17 NESCAUM

(Jason Grumet)

Encourages State participation

in the FLAG process;

supports cumulative

modeling, but requests

guidance on which sources to

include in such an analysis;

clarify what "very large

sources" >100 km would

require FLM notification.

Supports goal of achieving

natural background

conditions, but the FLAG

background visual range

recommendation is

inconsistent with EPA

guidance; the f(RH) values

are too conservative for the

Northeast areas and do not

adequately reflect the lower

humidity during daylight

hours; recommends that

f(RH) values be consistent

with the Regional haze

Rule (i.e., 5 years and

based on 20% best/worst

days).

Dry = wet deposition is a

reasonable default

assumption, but

refinements are needed for

site-specific areas; suggests

that 10 kg/ha/yr nitrate

deposition represents

adverse impact level.
13

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

18 TVA (John Shipp) FLM role regarding AQRV

protection under the CAA is

limited to Class I areas; the

referenced databases need to

be more available to the

public; recommends as

AQRV-impact audit process

to check for FLM consistency;

rather than stating "very large

sources" >100km are of

concern, develop some

specific size/distance criteria;

guidance should reflect that a

cumulative increment analysis

is only required if the source

exceeds significant impact

levels; FLM should specify

time limits for when they will

provide necessary data to

applicants.

Better distinction is needed

for the various thresholds

provided; visibility

prescription discussed on

pages 31-33 is inconsistent

with that in Figure V-1 on

p.33; the RH region for the

eastern U.S. needs to be

subdivided to reflect the

more humid conditions in

the southeast; TVA request

FLAG also include a plume

impact example calculation.

More specifics are needed

for nitrogen deposition

indicators; public needs

assess to AQUIMS to

evaluate the merits of this

database; the deposition

effects procedure needs to

be better defined and

clarified.

This section overstates

ozone research

findings; using a 24-hr

time period for W126

is unjustified; add a

column to Tables O-1

and O-2 and provide a

published reference for

each species;

recommend a

certification process for

FLM personnel who

conduct O3 injury

assessments; why is the

FLM concerned about

foliar injury on

invasive exotics?

Appendix 3B contains

many inconsistencies

and should be revised.

19 Gas Research

Institute (Jeffrey

Panek)

Would like a meeting to

discuss the comments; more

stakeholder involvement

should have been provided;

the FLAG report contains

insufficient documentation on

many fundamental technical

assumptions; FLAG should

address how and when

methodologies and AQRVs

will be revised; FLAG should

provide a discussion of

consistent Class I significant

FLAG metric is

inconsistent with the

Regional Haze Rule (Bext vs

deciview); clarification is

needed regarding natural

background visual range

calculations; FLAG should

provide the basis and

support for the various

visibility thresholds; FLAG

should define the nature of

a cumulative analysis and

how it should be

Recommended method to

quantify cumulative

impacts should be revised;

methods used to quantify

impacts to sensitive

receptors from ambient

pollutant concentrations is

not provided; deposition

impacts are likely to be

understated because cloud

water impaction is not

addressed.

Until appropriate

screening models are

developed, FLAG

should not deal with

O3 impacts on AQRVs

and should not pursue

additional NOx

emission controls as an

O3 reduction strategy;

not all areas are NOx

limited and further

justification of this

assumption is needed;
14

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

impact levels and define

criteria required to

demonstrate insignificant

impacts; FLAG should

address the relationship

between NSR, NEPA , and

the Regional Haze Rule;

FLAG should develop

guidelines regarding use of

emission offsets to mitigate

adverse impacts; fire and

mobile emissions can be

significant and their impacts

should be addressed.

conducted; cumulative

impacts from NEPA and

PSD analyses are not

interchangeable; basis for

RH and f(RH) assumptions

need to be provided;

applicants should provided

flexibility regarding which

CALPUFF modeling

assumptions to make.

the averaging time of

the N100 metric is not

defined; the basis and

relevancy of the W126

metric needs to be

provided; effects of

mobile sources on

ozone formation needs

to be evaluated as part

of any ozone study.

20 Lignite Energy

Council (John

Dwyer)

FLAG report is a substantive

rule that should meet

Administrative Procedure Act

requirements and include an

economic impact analysis;

FLAG should make clear that

the FLM bears the

responsibility for analysis and

must provide the input to the

State (don't shift this burden

to the applicant); FLMs

should reconsider the

requirement that applicants

provide cumulative impact

analyses and establishing

conditions when uncertainty

exists regarding potential

adverse impacts; FLAG

should not be used to
15

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

circumvent legislation or

judicial decisions. FLAG

should define "very large

sources" > 100km (coal-fired

sources 500 MW or less at a

distance greater than 100 km

from a Class I area should be

exempt from FLM

notification).

21 Wyoming DEQ

(Dan Olson)

The requirement for

cumulative assessment of

visibility and AQRV impacts,

and consideration of applying

better than BACT controls

and obtaining emission offsets

are inconsistent with WY and

EPA regulations; revise p.152

to reflect Clif Benoit's recent

retirement.

Some of the natural

conditions presented in

Table 2.B-1 are dirtier than

that of the mean of the

cleanest 20% days

monitored in some Class I

areas--the cleaner values

should be used; please cite

the basis for the 95%

relative humidity cutoff--

EPA guidance cites only a

90% and 98% RH cutoff;

please print the f(RH) value

next to each RH region on

p.39.

22 Colorado Mining

Assoc. (Dianna

Orf)

FLMs have seized upon a

single charge set forth in

Section of 165 of the CAA

and have constructed an entire

program of environmental

protection under the guise of

"guidance"; FLAG usurps the

authority of EPA and State

permitting authorities; FLAG
16

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

establishes de facto standards

and circumvents the

Administrative Procedures

Act and ignores balancing of

economic interests; FLAG

improperly expands the

definition of AQRVs; FLAG

expands FLM authority

beyond role set by Congress;

FLAG improperly shifts the

legal and financial burdens of

demonstrating impacts;

"Adverse Impact" is vague

and subject to arbitrary

interpretation.

23 Vermont DEC

(Paul Wishinski)

Recognizes adverse visibility

and deposition (S and N) exist

at Lye Brook WA; supports

FLAG process 100%;

encourages NESCAUM

coordination in Phase II;

guidance on what constitutes a

"very large source" beyond

100 km should be developed,

recognizing that utilities as

much as 1000 km have

transport potential.

Clarification is needed as to

how current baseline

conditions mesh with the

requested cumulative

impact modeling; FLAG's

recommendation regarding

use of natural background

and f(RH) values are

appropriate.

Provided copy of report

entitled, "Is Nitrogen

Deposition a Serious

Issue?, and requested that

FLAG reference it in the

final report; dry = wet

deposition is a reasonable

default assumption, but

refinements are needed for

site-specific areas; suggests

that 10 kg/ha/yr nitrate

deposition represents

adverse impact level.

24 American Public

Power Association

(Bill Wemhoff)

Supports comments provided

by WEST Associates and

UARG; FLAG should not be

used to push states to a

different program by

Supports comments

provided by WEST

Associates and UARG.

Supports comments

provided by WEST

Associates and UARG.

Supports comments

provided by WEST

Associates and UARG.
17

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

establishing new standards;

FLAG should be integrated

with other programs

(Regional Haze Rule, NSR

Reform, NAAQS, MACT,

etc.); FLMs should assess

economic impacts of FLAG

implementation; request for

greater public participation.

25 Phelps Dodge

(Shawn Kendall)

Provided extensive

comments and analysis of

visibility section, including

the following key points:

cumulative analyses must

consider emission

reductions as well as

increases; CALPUFF

limited for multi-source

applications; technical and

operational resource

requirements of the

modeling analysis are

severe and far exceed PSD

requirements (small

businesses can't afford

associated consulting

expenses); visibility

thresholds are unworkable,

arbitrary, and can't be

detected or measured; PSD

regulations provide States

discretion to balance

several factors, including
18

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

potential visibility impacts;

visibility techniques are

inconsistent with the

Regional Haze Rule.

26 American Forest &

Paper Assoc.; API;

Assoc. of Imported

Auto

manufactures;

National Mining

Assoc. (Ellen

Siegler)

FLAG shifts burden of proof

when increment not violated;

definitions of AQRV and

adverse impact are imprecise

and subjective; no basis to

require cumulative impacts--

should look at new source

only; no basis for LAER

control---FLMs shouldn't

waste valuable time doing

BACT reviews; FLAG will

result in significant burdens

and delays without achieving

environmental benefits.

Reliance on

CALPUFF/CALMET is

misplaced; no basis for

established visibility

thresholds.

Recommend FLMs

withdraw this section until

better data and models to

assess impacts are

available; public input

needed in establishing

critical loads.

Premature to address

O3 impacts since no

models available--

recommend FLMs

delete this section and

defer it to Phase II;

W126 alone will not

provide an accurate

estimate of vegetation

growth loss; too broad

of a generalization to

assume all areas are

NOx limited.

27 WEST Associates

(Nader Mansour)

WEST Associates

commissioned Paul Seby to

review the policy section. Mr.

Seby provided detailed

comments and

recommendations including:

FLAG is inconsistent with

CAA requirements of Section

165---shifts burden of proof to

applicant when increment not

violated, can't require new

source to assess cumulative

impacts or Class II impacts;

FLAG report is a legislative

rule that must comply with the

WEST Associates

commissioned Dr. Ivar

Tomback to review the

visibility section. Dr.

Tomback provided detailed

comments and

recommendations

including: FLAG approach

is inconsistent with EPA

"Plume Visibility

Workbook" and IWAQM

guidance (e.g., use of

natural background,

different thresholds for

"refined" plume analysis);

WEST Associates

commissioned Dr. George

Hidy to review the

deposition section. Dr.

Hidy provided detailed

comments and

recommendations

including: critical load

information should be

based on direct studies in

Class I areas; FLAG fails to

address impacts of fire and

mobile sources.

WEST Associates

commissioned Dr.

Allen Lefohn to review

the ozone section. Dr.

Lefohn provided

detailed comments and

recommendations

including: much

information presented

is inconsistent with the

realities of current

knowledge and should

be eliminated; both

W126 and N100 values

must be used together
19

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

procedural safeguards of the

Administrative Procedure Act;

FLAG is not consistent with

federal authority under the

Property Clause of the federal

Constitution because the

FLMs are not authorized to

regulate non-federal property;

FLMs must assess potential

economic consequences

associated with implementing

FLAG recommendations; key

information is missing from

the FLAG report on which the

public cannot comment; the

FLAG process places a

disproportionate burden on

new or modified sources in

the western U.S.

f(RH) definition for

different areas of the

country is unsound;

CALPUFF is unable to

compute credible sulfate

impacts in the presence of

clouds; FLAG fails to

account for fire emissions

in estimating natural

conditions.

to establish vegetation

growth loss; should

only rely on continuous

O3 monitoring data to

calculate W126 and

N100 metrics---passive

samplers provide only

limited data relating O3

exposure to plant

response; FLAG should

not rely on unrealistic

experimental exposure

protocols (i.e., 1.5 and

2.0 time ambient);

FLAG must develop

regional fumigation

facilities to produce

exposure-response

information that takes

into account east-west

differences.

28 EPA-Region 4

(Doug Neeley)

Suggests that the report be

limited to Class I areas; if

Class II areas included, they

should be explicitly identified

with corresponding AQRV

identification and evaluation

techniques; to the extent

possible, FLAG should

discuss effects of other

pollutants (e.g., heavy

metals); although cultural

resources are included in the

Report should also

address the current 1-hr

O3 NAAQS; include

reference on models

used to show NOx

offsets would result in

O3 benefit; numerous

issues would need to be

addressed before EPA

could institute regional

ozone permit modeling.
20

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

definition of AQRV, it

appears that cultural effects

are not addressed in the

report; the basis and definition

should be provided for each

de minimis level used; it

would be helpful to provide

the procedures used to

identify the applicable

AQRVs for each Class I area

and a reference as to where a

current AQRV list can be

obtained; more definitive

guidance should be provided

regarding "very large sources"

> 100km; provides some

suggestions to clarify

individual FLM, applicant,

and permitting authority

responsibilities; replace

"polluter" with "applicant";

recommend that all

appendices be placed at the

end of the report instead of at

the end of each section; SIPs

do not provide a mechanism

to address AQRV impacts in

nonattainment areas

29 Maine DEP (Tom

Downs)

Report was well organized,

researched and written; FLAG

should define "screening"

criteria for determining what

constitutes "very large

Visibility thresholds should

be consistent for Class I

areas on a regional basis;

using natural background

visual ranges in the plume

Table D2---RooseveltCampobello was omitted

from these tables.
21

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

sources" >100 km;

discussions regarding the

revised PM and O3 NAAQS

should reflect recent Court of

Appeals decisions.

impact modeling is too

conservative causing an

unnecessary burden on the

applicant; because the

cumulative visibility

analysis would be resource

intensive, recommend a

regional modeling approach

be undertaken as suggested

in IWAQM; FLAG's

recommended cumulative

visibility analysis approach

is inconsistent with the

Regional Haze Rule;

recommend that f(RH)

factors be calculated and

used for daylight hours; to

be consistent with the

Regional Haze Rule, the

f(RH) values should be

based on 5-yrs of relevant

data using the 20% least

impaired days.

30 Appalachian

Mountain Club

(Bruce Hill)

Support FLAG and

recommends that it move

forward, including Phase II;

FLAG should play a stronger

role in mitigating existing

source impacts; recommends

that FLAG include statistics

regarding past permits near

Class I areas (i.e., #, year,

location, etc.) and a map

Recommends tighter

visibility thresholds and

ratcheting down over time.

Recommend FLMs

continue efforts to establish

critical loads; recommend

more deposition

monitoring, perhaps

cooperative ventures with

applicants.

FLMs need to pay

more attention to

human health as an

AQRV; don't concur

with using N100 metric

because vegetation

effect occur well below

this level; not clear

why SUM06 metric

wasn't used.
22

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

showing areas currently

adversely impacted;

encourages formation of

research partnerships; strongly

supports FLAG's approach to

assess cumulative impact--

can't just look at proposed

source alone; to protect

downwind areas, recommend

adoption of a 500-1000 km

FLM notification threshold

for "very large sources";

FLMs should announce

peliminary adverse impact

det. in the Federal Register so

public can comment.

31 Minnesota Power

(Brandon Krogh)

Need to better clarify roles of

the FLM and permit

applicant---believe the AQRV

analysis should be conducted

by the FLM, not the applicant;

"very large sources" > 100 km

leads to unnecessary

confusion---recommend

providing specific numbers

and limiting review to sources

within 100 km.

32 Illinois Power

(Aric Diericx)

The FLM, not the applicant,

should assess potential

impacts on AQRVs; no basis

to require cumulative impact

modeling or for a State to

require emission offsets if the

FLAG should acknowledge

the modeling limitations for

assessing impacts >50 km.
23

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

source would not cause an

adverse impact on an AQRV

by itself; "very large sources"

> 100 km leads to

unnecessary confusion.

33 Independent

Petroleum Assoc.

of Mountain States

(Marc Smith)

FLAG report is a substantive

rule that should meet

Administrative Procedure Act

requirements and include an

economic impact analysis;

Congress established the

Class I increments to protect

AQRVs while FLAG

attempts to establish new

standards that obviates the

existing Class I standards;

FLAG process would disrupt

the federal-State relationship

established by the CAA;

FLAG's definition of AQRV

is more expansive that that

defined by Congress and

extends the definition to

encompass ecosystem

management; no basis for

cumulative impact studies

when the statute only allows

evaluation of the impact of the

proposed source; no basis to

require LAER or offsets;

determining sensitive AQRVs

is the FLM's responsibility,

research money should be

Definition of natural

conditions does not include

considerations of fire is

assessing AQRV impacts;

FLAG does not recognize

the existing limitations of

air quality models;

visibility thresholds are

extremely low; listed

backgrounds are not

consistent with

backgrounds given during

permit modeling efforts;

CALPUFF in screen mode

can only handle single

sources, full mode option is

very costly and not listed in

the IWAQM protocol;

FLMs without adequate

background in air modeling

are allowed to choose

parameters for modeling;

flawed assumptions

regarding humidity regions.

Deposition websites used

for reference in the report

do not have populated data

fields.
24

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

sought through Congressional

appropriation, not applicant

extortion; in many areas, the

FLAG report lacks supporting

or credible data.

34 U.S. Steel (Willian

Kubiak)

Clarify assessment method

when closest point is w/in

50 km and farthest point is

>50 km; plume analysis

using natural background is

inconsistent with EPA

guidance; there is no basis

for separate screening and

refined impairment for

plume analysis; FLAG haze

assumptions are overly

conservative.

Facility should be given the

opportunity to show what

the deposition impacts of

the new sources would be.

FLAG should solicit

input from the

applicant regarding

likely impacts.

35 Utility Air

Regulatory Group

(Mike Teague)

States have primacy role in

NSR; CAA does not require

cumulative AQRV impact

analyses (facility "will have",

not cause or contribute to"

language); FLAG expands

FLM statutory authority by

shifting AQRV analysis

requirements from the FLM to

the applicant; FLAG raises

more questions that it

answers; requests more

stakeholder involvement.

FLAG doesn't justify its

threshold levels.

36 Center for Energy

and Economic

Development and

Recommends FLMs withdraw

the report and seek

stakeholder input w.r.t. "next

FLAG's proposal to

establish new standards and

new analytical methods is

FLAG sets different and

more stringent standards

than those developed by

FLAG is a direct attack

on the scientific

validity of EPA
25

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

Western Fuels

Assoc. (Fred

Palmer/Terry

Ross)

steps"; key flaw is that FLMs

don't have CAA authority to

define AQRVs and

unacceptable AQRV impacts-

-these responsibilities clearly

rest with the States; FLAG

exceeds FLM's statutory

authority--shifts burden of

proof; no basis for cumulative

analysis (must show source

"will have" adverse impact,

not "cause or contribute to");

FLAG fails to establish

deadlines for FLM action.

duplicative, wasteful,

unnecessary, and

destructive of the CAA

visibility program; 0.4% de

minimis threshold is too

stringent and far below the

range of human

perceptibility.

EPA. secondary O3 NAAQS.

37 Hoosier Energy

(Paul Reynolds)

Recommends broader

stakeholder input; FLAG

report is a substantive rule

that should meet

Administrative Procedure Act

requirements and include an

economic impact analysis;

FLAG exceeds FLM's

statutory role by shifting the

burden of proof when the

increment is not violated; no

basis to require cumulative

analysis (source "will have"

language).

Using natural background

is inconsistent with EPA

and IWAQM guidance and

is problematic because

natural conditions are not

well defined; CALPUFF

doesn't adequately address

how clouds or fog affect

sulfate formation.

FLAG falls short in

providing a rational basis

for evaluating deposition

impacts; FLMs must

establish realistic LACs.

FLAG doesn't

adequately address the

effect of natural O3

background; must use

both W126 and N100

metrics to establish

vegetation growth loss;

must rely on

continuous O3

monitoring data, not

passive data.

 38 Petroleum Assoc.

of WY (Tom

Clayson)

Concerned about potential for

significant impacts to the oil

and gas industry; recommends

further stakeholder

involvement; supports

Supports comments filed by

Research Gas Institute.

Supports comments filed by

Research Gas Institute.

Supports comments

filed by Research Gas

Institute.
26

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

comments filed by Research

Gas Institute.

39 South Carolina

DHEC (Pat

Walker)

What is the definition of "very

large sources" > 100 km?; any

available screening out

criteria?; a common

concerned voiced by states

and industry is the FLM

making changes concerning

Class I analyses during the

permit review process--are

there plans to hold Class I

analysis requirement stable

provided the application is

moving forward at an

acceptable pace?; is there a

list of Class I areas that

certified existing adverse

impacts?; what process must

the FLM go through to certify

existing adverse impacts?; it's

the permitting authority's

responsibility, not the FLM's,

to make a final determination

on the impact status; clarify

when economics would be of

lesser importance in BACT

analysis; SC can not require

LAER in attainment areas for

pollutants other than VOC;

SC recommends FLMs

consider incentives to

industry, i.e., the FLM could

State may not have

authority to consider

cumulative effects of

visibility in the review of a

specific project's visibility

impact; FLAG needs to

more adequately define

what minimal impact can

be considered "acceptable."
27

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

agree to a decreased review

time and acceptance of a

project if the facility included

LAER and agreed-upon

offsets in the initial

application.

40 State of Montana

(Bob Habeck)

Explain what happens when

the State does not agree with

the FLM regarding source

impact on visibility---what

legal recourse is available to

the FLMs?; don't exclude

permitting authorities when

determining adverse impact

levels; activity fuel burning

for hazard reduction and

silvicultural treatment also

represent a large amount of

emissions that should be

addressed.

41 Nucor Corp.

(Steve Rowlan)

FLMs should publish AQRVs

in the Federal Register for

public comment; clarify "very

large sources" > 100km;

FLMs should not routinely

review BACT; replace

"polluter" with "permit

applicant"; FLAG shifts the

burden of proof from FLM to

applicant when increment not

violated; need to clarify basis

and intent of cumulative

analyses; no basis to expand

Clarify use of CALPUFFscreen vs. CALPUFFrefined mode; recognize

monitoring option (i.e.,

IMPROVE data) for

assessing cumulative

visibility impacts.
28

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

AQRV review to Class II

areas; address historical

degradation through SIP

process not NSR; need to

define "adequate mitigation".

42 Environmental

Defense (Vickie

Patton/Elissa Gutt)

Must examine new sources in

the context of actual & known

environmental concerns (i.e.,

cumulative impact analyses);

applicant has responsibility to

assess impacts and provide

necessary information to

FLMs; FLMs must remedy

existing source impacts; use

the power of the internet to

inform the public.

Recommend FLMs build

on Europe's advances on

establishing critical loads;

FLMs should update

critical load information

based on 5-yr reviews;

dry=wet assumption may

be inappropriate in many

areas; need to clarify

specific terms and

definitions; concerned

about inaction when

impacts unknown--need to

be more proactive

(preconstruction vs. postconstructing monitoring).

Concerned about

inaction when impacts

unknown--need to be

more proactive

(preconstruction vs.

post-constructing

monitoring).

43 Colorado

Petroleum Assoc.

(Stan Dempsey)

Supports comments submitted

by GRI and CACI; lack of

stakeholder involvement in

the FLAG process is

troubling; more discussion is

needed regarding FLAG's

relationship to other

regulatory programs (e.g.,

Regional Haze Rule, NEPA,

NSR Reform);

44 Idaho DEQ (Diane

Riley)

Document is trying to reach

too large of an audience, as a
29

No. ORG. POLICY VISIBILITY DEPOSITION OZONE

result the report is lengthy and

difficult to wade through;

classifying visibility

impairment caused by

naturally ignited fires as

natural is still being hotly

debated; clarify when land

management plans are

grandfathered from

conformity determinations.

45 Golder Associates

(Steve Marks)

Applicants should be

allowed to propose more

realistic ammonia and O3

background values in full

CALPUFF modeling.