This is a preliminary document prepared by a subgroup member of the Base Programs Analyses and Policies work group as part of the Federal Advisory Committee Act (FACA) Subcommittee process. It is not an EPA document. This document has not been reviewed by the work group and is subject to further work group discussion. Interested people should forward their comments to a member of the Base Programs Analyses and Policies (BPA&P) work group.

Phase II Implementation Strategy for Contingency Measures/Maintenance Plans

Date: April 28, 1997

Status: Draft #3 - Incorporates comments from the BPA&P work group conference call (April 15, 1997) and a working call with David Cole, Annie Nikbakht and Eric Skelton on April 17, 1997. The notes in the text are mainly from Eric Skelton.

Contact: Eric Skelton, representing the BPA&P work group @ (509) 456-4727 x121, FAX: (509) 459-6828

Introduction

This paper addresses contingency measures and maintenance plans in both attainment and nonattainment areas under the new/revised ozone and PM national ambient air quality standard (NAAQS) as well as the regional haze program.

Background

There are two types of contingency measures used in a SIP program. First, contingency measures are used to promptly correct a violation of the NAAQS in a maintenance area after attaining the standard. Second, contingency measures are also used to assist a nonattainment area in meeting reasonable further progress (RFP) or to attain the NAAQS by a certain date [sec. 172(c)(9) and sec. 182(c)(9)]. The contingency provisions in subpart 1 [sec. 172(a)(9)] are the general contingency measures and apply to all SIPs for criteria pollutants. The contingency provisions found in subpart 2 [sec. 182(c)(9)] were part of the Clean Air Act Amendments of 1990 (CAAA) and apply only to those SIPs for ozone nonattainment areas. The general preamble to implement Title I of the CAAA (57 FR 13498) attempted to suggest what should be in the list of contingency measures (i.e., 3 percent of VOC or NOX) however, there was never a clear definition as to how much correction would be triggered. In the context of the RFP discussions for the new/revised standards, the general idea of contingency measures seems to be a process that first triggers a set of reductions, and at the same time initiates an analysis to determine the seriousness of the problem. Additional reductions may be implemented as part of mid-course corrections to ensure full remedy of the problem. In practice, contingency measures have basically required the implementation of some new reductions that at face value seem sufficient to correct the problem. The new/revised standards are proposed to be covered under the subpart 1 contingency provisions. How the new/revised standard relate to subpart 2 contingency provisions [sec. 182(c)(9)] will be discussed in greater detail as part of Issue 9. Maintenance plans ensure continued attainment of the air quality standards after an area violating the standard attains the standard [sec. 175A(d)].

Contingency Measures for Nonattainment Areas or Areas of Violation

Historically contingency measures have also been defined as specific measures to be undertaken if a nonattainment area fails to make RFP, or to attain the NAAQS (i.e., ozone or PM-10) by the applicable attainment date. These contingency measures are included in a State's SIP. Reductions must be achieved promptly (i.e., in the year following that in which the failure was identified).

For ozone, contingency measures must be fully adopted rules or measures. The measures do not have to be implemented unless and until they are triggered by either failure to meet a milestone in RFP or attain the NAAQS. The SIP should clearly state the trigger mechanisms, a schedule of the implementation of the measures, and an indication that the measures will be implemented with no further action by the State or EPA. Contingency measures prior to November 15, 1996 (pre-1996), had to address VOC reductions while post-1996 contingency measures could address reductions for VOC and/or NOX. EPA allows for the post-1996 contingency measures to provide for less than 3 percent in VOC reductions as long as the difference is made up in Nox reductions. Examples of ozone contingency plan measures include, but are not limited to, Stage II vapor recovery, enhanced inspection/maintenance programs, or VOC control on minor (i.e., less than 100 tons per year) new sources.

PM-10 contingency plans generally have no set rules other than allowing the area to regain RFP or attain the PM-10 NAAQS. Examples of PM-10 contingency plan measures include, but are not limited to, substituting liquid deicers for sand and/or road salt, and implementing residential wood combustion (RWC) curtailment programs.

Contingency Measures for Attainment Areas

1. Areas Redesignated as Attainment for the NAAQS

When the redesignated area has violated the relevant NAAQS, contingency provisions listed in the maintenance plan are invoked to make prompt corrections that will bring the area back into attainment. There are two types of contingency measures which can be used in the maintenance plan.

The first types of contingency measures are statutorily-mandated control programs that were not implemented prior to submittal of the redesignation request. [Question: Under the new/revised NAAQS, would EPA adopted national measures take the place of subpart 2 control measures?] In this case, EPA allows the State to move these measures from the implemented SIP to the contingency measures portion of the SIP provided the State demonstrates that such measures are not needed for maintaining the NAAQS. These contingency measures can then be folded into the maintenance plan for the area. Certain specific programs, such as basic I/M, were required to be adopted by the state and approved by EPA in order for the State to have a fully approved SIP. EPA will accept, in lieu of actual adoption, legislative authority for such programs and allow such measures to be placed as contingency measures in the maintenance plan, provided the State demonstrates such measures are not needed to maintain the NAAQS.

The second type of contingency measures initially do not need to be fully adopted and can simply be listed. However, the contingency measures in the maintenance plan are considered an enforceable part of the SIP, and the measures must be adopted expediently once they are triggered. The maintenance plan identifies the specific triggers or indicators used, the specific measure(s) to be adopted, a schedule and procedure for adoption and implementation of the measure, and a specific time limit for action by the State.

2. Area Always in Attainment with the NAAQS

These are the areas that have always attained the standard and are included in the maintenance SIPs submitted to EPA in 1972. As a rule, these SIPs do not include contingency measures to correct any violation of the standard.

Maintenance Plans

When a State submits a request to EPA to redesignate a nonattainment area to attainment for a particular pollutant, the package must contain an approvable maintenance plan. The maintenance plan constitutes a SIP revision and must provide for maintenance of the NAAQS in the area for at least 10 years after redesignation. Eight years after the original redesignation request is approved, the area must submit a revision to the SIP to provide for maintenance of the NAAQS for an additional 10 years following the first 10-year period. The maintenance plan contains contingency measures to ensure prompt correction of any violation of the NAAQS that might occur after redesignation to attainment.

A base year attainment inventory identifies the level of emissions from various sources in the area sufficient to attain and maintain the NAAQS. This inventory includes all the sources included in the SIP attainment demonstration (i.e., stationary, area, and mobile sources). For ozone areas, the base year inventory is based on a typical summer day during the attainment year and generally corresponds to one of the 3 years for which monitored air quality data were collected. This is analogous to the emissions budget under conformity. Any relationship between the attainment inventory and emissions budget will be discussed further in the Transportation Conformity issue paper.

There are two methods by which an area may develop an emissions inventory for the maintenance plan. The first method involves the use of actual emissions from the sources included in the attainment inventory. Stationary and area sources emissions are based on actual operating hours, production rates and control equipment for the processes in operation. Mobile sources emissions are based on factors such as vehicle fleet mix, vehicle miles traveled (VMT), and average vehicle speeds. The base year emissions inventory must be based on actual emissions. When developing maintenance projections for the ten-year period, the State may base the projections on actual or allowable emissions. As long as the State does not anticipate subjecting the source to any future or additional regulations, actual emissions can be used. However, if the State anticipates subjecting a source to future or additional regulations, the projection must be based on the new allowable emissions limits because the new actual emissions are not yet known.2

The second method is generally used to develop attainment inventories for PM-10 nonattainment areas. This emissions inventory uses the maximum allowable emissions based on enforceable (i.e., allowable or permitted) emission rates, the maximum operating capacity, and continuous operations (unless there are federally enforceable limits on operating hours) for each major point source.2 EPA requires the use of maximum allowable emission limits for major point sources to demonstrate maintenance of short-term standards. This differs from the ozone requirement since large point sources have the ability to cause an exceedance of the applicable NAAQS when operating at full capacity.

An area may demonstrate maintenance of the NAAQS by showing that future emissions of a pollutant or its precursors will not exceed the level of the attainment inventory, or by modeling to show that the future mixes of sources and emission rates will not cause a violation of the NAAQS. In both instances, the demonstrations should be for a period of 10 years following the area's redesignation to attainment. Any assumptions concerning emission rates must reflect permanent, enforceable measures. Thus, the area is expected to maintain its implemented control strategy despite redesignation to attainment. The only exceptions would be if the control strategy was shown to be unnecessary for maintenance or replaced with measures that achieve equivalent reductions. At a minimum, previously adopted and/or implemented measures that are no longer needed for maintenance must be rolled over as contingency measures for the maintenance plan.

[Note: I am not so sure that this exception is very applicable to the new NAAQS. The cases where this was used were measures prescribed by the CAAA, such as enhanced I/M. If the new programs prescribe specific measures for all AOIs, then this substitution/exemption provision may be necessary, but if there are no new prescribed measures, then presumably nobody would be adopting control measures which they later determine to be unnecessary.]

The area also needs to indicate how it will track the progress of the maintenance plan. One example is to periodically update the emissions inventory. In this case, the maintenance plan should specify the frequency (i.e., annually, every 3 years, etc.) of any planned inventory updates. An alternative to a complete update of the inventory could be a comprehensive review of the factors used to develop the inventory, such as VMT growth, population growth, spatial distribution shifts in population and sources. If this review does show significant changes, then the area could perform an update of the inventory. If modeling was used to demonstrate maintenance of the standard, an option for tracking progress is to periodically reevaluate the modeling assumptions and input data.

[Question: In order to reevaluate the modeling assumptions, don't you have to reevaluate the inventory? If so, then is a modeling assumption review really an option to an updated inventory?]

ISSUES

1. Can contingency measures be episodic? Can episodic contingency measures be included in the core measures for the SIP? Historically, episodic measures have been more applicable to area and mobile sources of emissions than to point sources of emissions. Episodic measures may be difficult to apply to point sources since most point sources are already controlled to some degree. Additional reductions may not be available from these point sources to the degree required for episodic measures to have a significant impact on ambient concentrations. However, this does not preclude the use of episodic control strategies on a point source especially if the source is well controlled to start with and the next level of continuous control should prove to be cost prohibitive. To what extent does cost factor into the use of episodic measures as part of the contingency measures?

Ozone strategies, according to EPA guidance, were required to be real, permanent, quantifiable, and enforceable. Episodic strategies traditionally have not been viewed as providing real, permanent, quantifiable, and enforceable emissions reductions, and therefore have not been considered as approvable for the contingency measure requirement under the existing NAAQS. The use of episodic strategies is a departure from the current interpretation of section 123 of the 1990 CAAA.

Currently, many western states have seasonal residential wood combustion (RWC) curtailment programs that curtail all wood burning except for sole-source heating. Such seasonal programs have proved successful and have subsequently been adopted in the SIP. These programs are generally triggered by the ambient concentration of PM-10 reaching a certain threshold (approximately 90 to 110 g/m3) and generally last for 24 hours or until temperature inversion conditions dissipate.

Pros: Episodic measures can be used to supplement SIP contingency measures. Episodic measures can achieve desired results. Some episodic measures may prove effective over time as public attitudes/awareness changes. Episodic measures can increase the public's understanding of their role in abatement.

Cons: There is some difficulty in predicting when episodic control measures are needed. In order to respond in a timely fashion, the threshold ambient concentration has to be set relatively low. This can result in a number of false positives (i.e., an area predicts a potential exceedance of the standard and episodic measures are implemented when the standard would not have been exceeded if the are did not take any actions). However, the modeling tools available today allow an area to reasonably predict ambient concentrations to avoid exceedances of the standard.

2. Can contingency measures be voluntary? For each AOI/AOV or nonattainment area, there is a core set of prescribed measures that are designed to bring the area into attainment with the standard. There may be some circumstances in which these measures may not get the area to attainment but rather close to attaining the standard. In this situation, voluntary measures may provide enough reductions to bring the area the rest of the way to attaining the standard. To what degree can voluntary measures be included as contingency measures? To what extent can cost factor into the use of voluntary measures as contingency measures? Examples of voluntary measure include, but are not limited to, no-drive days on ozone alert days.

Pros: Voluntary measures can be used to supplement SIP contingency measures. Voluntary measures can achieve desired results. Some voluntary measures may prove effective over time as public attitudes/awareness changes.

Cons: One of the work group members suggested that voluntary measures are "window dressing" serving only to make people feel good. States cannot tell ahead of time how effective a voluntary measure would be. Voluntary measure are not enforceable. Providing credit for voluntary programs may not be permissible under the Act.

3. What is the time frame for adoption of contingency measures in newly designated nonattainment areas? In the past, ozone SIPs were required to be submitted by November 1993. EPA allowed the States to submit contingency measures by November 1994. Will comparable separate submittal dates be allowed for the new/revised standards for ozone and PM-fine as well as regional haze?

Option 1. Allow a longer period of time.

Pros: Allow the area to determine what is needed for contingency measures. The area may not know the effect of the core SIP measures. Until the area knows the effectiveness of these measures, the area cannot develop effective contingency measures.

Cons: If the areas are allowed a long lead time and contingency measures are not in place, the area will have nothing to fall back on if it violates the standard or misses an RFP milestone.

Option 2. Allow a shorter period of time.

Pros: Contingency measures would be ready in a short period of time. This would provide the area with a fall back position if the area violates the standards or misses an RFP milestone.

Cons: The area may adopt contingency measures which may not provide enough emission reductions or the wrong type of emission reductions.

4. Is an area that implements maintenance plan contingency measures early, to avoid a violation of the new/revised standard, required to backfill with additional contingency measures? [Note: The Helms memorandum (8/13/93) suggested that nonattainment areas should not have to backfill. EPA has applied this reasoning to both maintenance and nonattainment areas.]

Option 1. The area is required to backfill with additional contingency measures.

Pros: Contingency measures would be ready to implement if needed by the area.

Cons: There will be additional resources expended to develop additional contingency measures. The area may develop contingency measures that may not be needed.

Option 2. The area will not be required to backfill with additional contingency measures.

Pros: The area can use the resources that would have been used to develop additional contingency measures for other attainment issues.

Cons: The area may not have contingency measures available as a fall back position if there is a violation of the standard or a missed RFP milestone.

[Propose that this issue be deleted and replaced with Issue 15.]

6. [This issue should be addressed in the Areas at Risk issue paper.] Could a contingency measure be used to expand the area of an AOI and broaden the applicability of the control measures? This would be a contingency measure that expanded the area of the AOI and made the requirements of the original area apply to the sources in the newly expanded area. One work group member commented that how the data are collected could have a tremendous impact on determining the area's designation status. If the data are averaged on a rolling 3-year period instead of a set 3-year time period, an AOV could conceivably fall in and out of attainment.

Pros: This would allow the expeditious implementation of control measures on applicable new sources in the expanded area of the AOI.

Cons: All the control measures in the original AOI may not be necessary for the sources in the expanded AOI. The AOI may have only needed to control the major sources in the expanded area. This may result in the AOI over controlling the sources included in the area. Could result in delays to increase the area from which to obtain reductions.

7. Will contingency measures be required for Class I areas for visibility purposes? Areas that violate the visibility standard will have specific goals and a time frame to attain the standard. Contingency measures will be required as a means to get the area back on track if it deviates from the implementation plan.

8. [There is an analogous relationship between the Transportation Conformity Emission budget and the attainment emission inventory. This issue should be addressed in the Transportation Conformity issue paper.]

9.

10.

New Issues from the Joint Work Group meeting (March 13 and 14, 1997)

11.

12.

[This issue should be addressed in the Economics Incentives issue paper.]

13. What can be used as a contingency measure other than emission reductions when an area determines they have controlled all that can be controlled and no additional measures are available? Additional contingency measure requirements may include, but not be limited to, reinventory of sources in the AOI, expand the AOI to capture more emissions, use technology forcing regulations, implement behavior based controls, obtain a waiver/extension of the attainment date [see recommendations in the Attainment Dates for New National Ambient Air Quality Standards (NAAQS), currently being revised], etc. Should a State have the ability to petition EPA for relief? What level of proof would be required for the area to demonstrate that they have truly done all they can? To what extent do economic factors determine the feasibility of a contingency measure?

14. [This issue should be addressed in the Integrated Implementation issue paper.]

15. Should measures that were used by an area to bring it into attainment for a pollutant standard be dropped from the maintenance plan?

[Note: Under what circumstances could you drop measures that you used to make attainment? Wouldn't this put you back into nonattainment?]

If an area drops a measure from a maintenance plan, the area must roll the measure over as a contingency measure and provide a technical demonstration showing the measure is no longer needed for maintenance. If a nonattainment area contingency measure(s) [under sec. 172(c)(9)] helps bring an area to attainment, the measure(s) should continue to be used in the maintenance plan in the event the area wishes to redesignate to attainment. If the State shows the measure is not needed to maintain the standard, it can be rolled over as a contingency measure in the maintenance plan. [Note: This issue is proposed to replace Issue 5.]

16. [This issue should be addressed in the Control Strategies issue paper.]

17. Should there be federally prescribed contingency measures for attainment and/or maintenance plans? Not referring to the rolling over of unimplemented prescribed measures into the contingency category, but rather the EPA formulation of measures that should be used as contingencies.