Tracking Visibility Progress in the Regional Haze Rule: Focusing the Reasonable Progress Framework on Controllable Emissions July 28 & 29, 2015 1:00 –

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Tracking Visibility Progress in the Regional

Haze Rule:Focusing the Reasonable Progress

Framework on Controllable Emissions

July 28 & 29, 20151:00 – 3:00 pm EDT (both days)

Call-in: 1-866-299-3188/Code: 919-541-5676#

Do Not Circulate Outside Agencies Involved in this Call

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Purpose of discussion:• Check-in to ensure EPA understands states’ concerns with the

current visibility tracking metric• Provide an update on EPA’s development of guidance to focus the

visibility tracking metric on controllable emissions• Receive input from states, tribes, and RPOs on the options presented

• During the calls and/or via email by August 7• High level reactions and/or comments on the details

Overview:• Review of the current framework for tracking visibility progress• Summary of what EPA has heard on this issue from states so far• Report out on recent technical workgroup activities• Present, in detail, options for focusing the glidepath on controllable

emissions

Purpose and Overview of the July 28 & 29 calls


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Current Progress Tracking Framework20

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• Elements of the framework• The annual metric to be calculated from

IMPROVE data• The glidepath to natural conditions in 2064

that is a point of comparison• The method for forecasting the effect of the

Long Term Strategy (LTS) on this metric, i.e., the reasonable progress goal (RPG) for the Class I area

• The mid-course progress reports track whether actual visibility as represented by the tracking metric is approaching the next RPG

• The Framework is only a framework for SIP development, not a rigid requirement or a safe harbor, under the existing RH Rule.• SIPs must contain emission controls necessary

for reasonable progress towards eliminating manmade visibility impairment

• If the RPG for 2028 is above the URP line, states have a special obligation to analyze what controls would be needed to achieve the URP and explain why they are not reasonable

• Reasonable progress is NOT simply defined as being on or below the URP line


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• Western states are facing difficulties in demonstrating actual progress in visibility in some Class I areas due to• Extreme, episodic natural events

(large fires, dust storms, etc.)• Non-U.S. anthropogenic emissions• Low 2064 natural conditions

estimates

• Eastern states are less concerned

• States have requested rule changes or guidance for focusing the framework on controllable emissions, so they can demonstrate progress they have made.

State Concerns with the Current Tracking Metrics

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Shenandoah National Park, VA

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RPG (hypothetical)


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• Public perception of state efforts and results, as communicated by IMPROVE data presented in the format of the EPA-required framework, is important.

• Eastern states understand the problem of the western states, but want a flexible structure so that they have the option of keeping the current simple approach.

• States generally want an standard/objective process for treating IMPROVE data, not a process with the subjective, weight of evidence nature of the Exceptional Events process.

• Elimination of all anthropogenic impairment by 2064 is not a realistic goal. Even elimination of just impairment by U.S. sources is not realistic.

• EPA should form a technical workgroup (including states, tribes, and RPOs) to explore details of potential approaches• EPA and FLM staff spent April and May developing needed software, example approaches, and plots.• ~20 representatives from states, tribes, and RPOs participated with EPA and FLM staff in a series of 5 calls in

June and July 2015.• EPA, FLM, and states presented approaches with example plots.• Discussions, at times, were very detailed.• The goal was to narrow approaches for this week’s calls to only as many as needed to illustrate conceptual

choices.• There are still some details that need to be explored.• I have used feedback I received during and after the June/July workgroup calls to finish narrowing options to

those being presented today (and tomorrow). This does not mean that only these options can go forward from here.

Input from March Meeting on Regional Haze


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Questions to consider as you provide feedback• If a poor visibility day has “large” contributions from both natural and anthropogenic

sources, how important is it to retain this day in the tracking metric for the 20% most impaired days ?

• What is your comfort level with the options for distinguishing non-extreme natural impacts from anthropogenic impacts, for every day and every Class I area?

• How important is the link between the metric used to track progress and measured/observed visibility? • Would any particular option confuse the public too much?

• How do you and how would the public view an “impairment” glidepath that has an endpoint of 0-1 dv?

• Would a new approach addressing only the 2064 endpoint of the URP to make it better reflect 5-year average natural conditions during the baseline period be sufficient from your perspective (i.e., would it be enough to make the URP less sloped but continue to have a bumpy trend line for some areas)?

• How would you view EPA guidance that all states should present a trend line of the current metric (as presently required) along with the new glidepath framework?

• How would you view EPA guidance that gave eastern states the option of not using the new glidepath framework at all?

• If modeling is the only approach that can be used to estimate the impacts of non-U.S. emissions, for the purpose of moving the 2064 endpoint upwards, what is your comfort level with the use of modeled estimates?


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June/July Workgroup Explored a Range of Options

Focus only on the extreme, episodic events OR Change tracking metric to Impairment

Remove/adjust IMPROVE data impacted by extreme events

and then continue tracking observable haze (Modifications

to the current approach)

Split each day of IMPROVE data into natural and anthropogenic fractions, and then track impairment (Fundamental change to the selection of days and tracking metric)

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Sawtooth Wilderness Area, ID

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June/July Workgroup Explored a Range of Options

1- Observable Haze on those Days (dv)

2- Impairment (Δdv)(Next slide has detail)

1- Worst days of the days that were not affected by extreme events

Explored 3 iterations: - Exclude days (option IA)- Cap impacted days- Adjust impacted data to median

(option IB)2- Worst days are the days that have highest light extinction from anthropogenic extinction (Mm-1)

Possible, but have not developed example options option II

3- Worst days are the days that have highest incremental impairment (Δdv)

Possible, but have not developed example options

Explored, but not presenting results today.

4- Worst days are those with highest dv (current approach)

This is the current framework approach (can revise 2064 natural conditions endpoint to better match the natural part of haze during the baseline period, option III)

What is tracked (the y-axis of the framework)?H

ow to

cho

ose

the

days

in th

e 20

% m

ost i

mpa

ired?


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Visibility impairment means any humanly perceptible change in visibility (light extinction, visual range, contrast, coloration) from that which would have existed under natural conditions.

Human perception of visibility is not linear. The starting point for the change matters:

• 10 Mm-1 of anthropogenic extinction on a background of 200Mm-1 is not perceptible

• 10 Mm-1 of anthropogenic extinction on a background of 20 Mm-1 is very perceptible

• Days with high “natural” extinction (e.g. from fires or dust) will have less “impairment” for the same anthropogenic extinction than days with less “natural”.

“Impairment” is equal to total haze minus natural haze, in deciviews.

dvimpairment = dvtotal - dvnatural

The concept of Impairment


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1) Split each day of IMPROVE data into natural and anthropogenic light extinction components

2) Sort• Decide how to sort only on anthropogenic extinction component (slide 8, row 2) or on

impairment (slide 8, row 3)

3) Natural Conditions• Requires use of natural conditions estimates in calculations each day, not just at the 2064

endpoint

4) Draw Glidepath for Impairment• Between baseline period and the 2064 endpoint of 1 dv (as indistinguishable from 0 dv)

Components of an Impairment-based Approach (e.g., Option II)

Anthro.

Natural

Bext

(Light Extinction)

One day of reconstructed extinction from IMPROVE data

• Bext = Anthropogenic + Natural • Natural = Bext – Anthropogenic• Anthropogenic = Bext – Natural


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Indicator of Events Considerations Potential improvements

95th percentiles of Carbon and Dust of regional groupings(currently used in options IA and II)

- Regional groupings allow more days to be identified at the sites within each region with the most ‘high’ days and recognize that natural events don’t always affect each location with equal frequency

- Allows the use of the 95th percentile, a common statistical indicator of outliers

- Refine groupings to be based on IMPROVE recommended groups

- Investigate site-by-site, percentile-based thresholds

- Sensitivity analysis

2 x (or 3 x) individual site medians of Carbon and Dust(currently used in option IB)

- Site-by-site approach considers the individuality of each site to a degree

- Generally results in a lower threshold than above (more days identified as event-affected)

- Combine with a statistical test for outliers

- Other threshold approach- Sensitivity analysis

Subjective, site-specific - More subjective on a one-time basis- More time to get closure due to the need to

study each site’s IMPROVE data- Could be done as EPA guidance, with FLM and

state input, or could let each state take the lead for its Class I areas

• Objective: Regardless of which box from slide 8 we decide upon, all have the need to identify when IMPROVE data are impacted by extreme, episodic events (e3).

• We want the identification approach to work when there are event-impacted data (and not when the data aren’t impacted by e3).

The Options for the Identification of Extreme, Episodic Extinction


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• Premise: Extremely elevated light extinction from carbon (OM+EC) and dust (Soil and CM) is related to major fire and dust events. Exclude from the 20% most impaired days, those days with concentrations of carbon or dust > regional threshold value

• Details (as currently applied): • Each Class I area assigned to a climate region • Group the areas within each climate region (other groupings possible)• Determine 95th percentile of the climate region distribution of values for carbon

and dust over 2000-2013 (other approaches possible)• Move days that exceed the threshold value to the center of the distribution (this

keeps the same number of days in the distribution)• These days no longer show up as 20% most impaired• 20% least impaired days are not affected• Metric is dvtotal (slide 9)

Option IA: Exclude Days


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Option IB: Replace Extreme Values of Carbon and/or Dust Extinction• Premise: Extremely elevated light extinction from carbon (OM+EC)

and dust (Soil and CM) is related to fire and dust events. Replace carbon or dust values that exceed threshold values with typical values

• Details (as currently applied): • Twice the median of 14 years of IMPROVE data from each monitor used as

threshold.• Replace extinction values of carbon and dust with the median value when

the concentrations exceed the threshold (2 x the median)• Re-sort days using adjusted extinction levels to identify 20% most

impaired.• 20% least impaired days are not affected (or not very often)• Metric is dvtotal (slide 9)


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• Premise: IMPROVE data can be partitioned between natural and anthropogenic well enough for our purposes. Days with the highest anthropogenic impacts should be the focus of the impairment-based tracking.

• Details (as currently applied): • Need to split data for each day into anthropogenic and natural fractions• Split each day’s extinction into 3 fractions: “normal” natural; extreme episodic

natural; and anthropogenic:• Sea Salt assume natural• Sulfate • Nitrate • OM • EC • Fine Soil • Coarse Mass

• Sort the IMPROVE data by anthropogenic light extinction• Metric is dvimpairment (slide 9)

Option II: Focus on Impairment on Days with Highest Anthropogenic Light Extinction

extinction above threshold values (used same as approach IA) as extreme, episodic natural; the Trijonis avg natural estimate is “normal” natural; and the remainder is anthropogenic

extinction above Trijonis avg natural values is anthropogenic


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• Premise: The major issue impacting states is that the 2064 endpoints should be revisited so that the slope of the URP is not distorted by inconsistent values for natural conditions, with particular attention focused on

1) Applying estimates of extreme impacts in the baseline period (2000-2004) to the 2064 endpoint

2) Also revising estimates of the “normal” natural conditions to be applied to 2064

• Details (as currently applied): • The EPA has not explored this option in detail, therefore we have no

examples to share• We would, presumably, apply some of what we’ve learned in the

identification of extreme events in options IA, IB, and II to this option, if we pursue it.

Option III: Focus efforts on the Revision of the 2064 Natural Conditions Estimates


16• This chart reflects how plots were prepared, the sensitivities of all components have not been fully explored!• There are many possible combinations possible, but given time constraints, we’ll be discussing only these.

Identify impacts of extreme, episodic events

SPLIT into episodic natural, anthropogenic, etc.

Eligible DAYS SORT for 20% most and least impaired

Y-axis on PLOT of Glidepath

ENDPOINT of Glidepath

IA- Exclude days

95th percentile regional thresholds for carbon and dust

n/a Only days with contributions below threshold values

Remaining days are considered to determine the 20% most and least impaired days.

deciviews default Natural Conditions II estimates of 20% most impaired days (or use average estimates).

IB- Replace event-impacted data with typical values

2 x the median (per site) and adjust extinction exceeding threshold to median

n/a All days Sort adjusted dataset to determine the 20% most and least impaired days.

deciviews default Natural Conditions II estimates of 20% most impaired days (or use average estimates).

II-Focus on impairment on days with highest anthropogenic haze

95th percentile regional thresholds for carbon and dust

Split each day into anthropogenic and natural fractions based on the natural conditions II estimates and the extreme event impacts; only anthropogenic remains

All days Sort days with highest anthropogenic light extinction

Difference in deciviews between total haze and natural haze

1 dv (as indistinguishable from 0 dv)*

III- Revise the 2064 endpoint only

n/a n/a All days Same as current deciviews Revised natural conditions estimates that are more consistent with the baseline period.

Current approach

n/a n/a All days All days considered and ranked based on total dv (or total light extinction)

deciviews default Natural Conditions II estimates of 20% most impaired days.

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Options IA and IB vs. Current Approach for Sawtooth

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Options IA and IB vs. Current Approach for Sawtooth

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Option II (Step 1) for Sawtooth: Split the Data


2012 Time Series

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Sawtooth

Absolute Anthropogenic Extinction - Impairment (II)

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Option II (Step 2) for Sawtooth: Sort the Data

Absolute Anthropogenic Extinction - Impairment (II)2012 Sorted


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Options IA and IB vs. Current Approach for Mesa Verde

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Options IA and IB vs. Current Approach for Mesa Verde

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Option II (Step 1) for Mesa Verde: Split the Data


2012 Time Series

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Option II (Step 2) for Mesa Verde: Sort the Data




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Options IA and IB vs. Current Approach for Shenandoah


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Options IA and IB vs. Current Approach for Shenandoah

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Option II (Step 1) for Shenandoah: Split the Data


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Option II (Step 1) for Shenandoah: Split the Data




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Which Class I areas are most affected by Option IA (Exclude Days)?

(dv/year)

Colors represent the difference between the slope of the line between the 5-year periods: 2000-2004 and 2009-2013; independent of the Glidepath

Negative/blue indicates a downward trend is more apparent with the option (or the upward trend is less strong); positive/red indicates the opposite effect

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Mesa Verde, CO


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Which Class I areas are most affected by Option IB (Adjust Days)?



(dv/year)


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Which Class I areas are most affected by Option II (Absolute Anthropogenic Impairment)?

(dv/year)




32Do Not Circulate Outside Agencies Involved in this Call

(dv/year)

All Options Together, for Comparison


Exclude Days (IA)

Replace Extreme Values (IB)

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Still Ahead: How to deal with non-US, anthropogenic contributions?

• One approach is to use modeled source apportionment (SA) results to raise the 2064 endpoint.

• Workgroup looked at results from one SA analysis in the west to investigate the range of results

• Identified the areas that need to be explored further:o boundary conditions that separate natural from anthropogenico boundary conditions estimates for 2064o model evaluation of PM species


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• I ran out of time…

Compare and Contrast Metric OptionsDoes the approach dampen the interannual variability from extreme natural events?

Would a day with simultaneously high natural and anthropogenic impacts be retained in the 20% most impaired days?

Sensitivity to threshold chosen to identify extreme events

Easy to explain?

Level of effort required to implement?

How different is the Modeling Process to set Reasonable Progress Goals (RPGs)

IA – Exclude Days

Yes Not necessarily TBD Easy Low Similar

IB – Replace Extreme Data

Yes Potentially yes TBD Moderate Low Similar

II – Impairment with focus on anthropogenic extinction

Yes Maybe TBD Most Challenging

Low Potentially different; needs more exploration

III – 2064 Endpoint Adjustments Only

No Yes n/a Easy Low (not counting process for reconsidering new “normal” natural conditions)

Similar

Current Approach

No Yes n/a Easy n/a n/a


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Questions to consider as you provide feedback• If a poor visibility day has “large” contributions from both natural and anthropogenic

sources, how important is it to retain this day in the tracking metric for the 20% most impaired days ?

• What is your comfort level with the options for distinguishing non-extreme natural impacts from anthropogenic impacts, for every day and every Class I area?

• How important is the link between the metric used to track progress and measured/observed visibility? • Would any particular option confuse the public too much?

• How do you and how would the public view an “impairment” glidepath that has an endpoint of 0-1 dv?

• Would a new approach addressing only the 2064 endpoint of the URP to make it better reflect 5-year average natural conditions during the baseline period be sufficient from your perspective (i.e., would it be enough to make the URP less sloped but continue to have a bumpy trend line for some areas)?

• How would you view EPA guidance that all states should present a trend line of the current metric (as presently required) along with the new glidepath framework?

• How would you view EPA guidance that gave eastern states the option of not using the new glidepath framework at all?

• If modeling is the only approach that can be used to estimate the impacts of non-U.S. emissions, for the purpose of moving the 2064 endpoint upwards, what is your comfort level with the use of modeled estimates?


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Assistant Administrator-level review of full external draft guidance

Revisions based on comments

Dec 2015 Feb-May 2016

Glidepath options and examples presented to a similar sized audience as the March 3 & 4 meeting to hear individual feedback. (other topics include rule updates and RP guidance)

July-August 2015

Small workgroup with technical state/tribal/RPO representatives to explore options; included EPA and FLM

June 2015

Timing and Next StepsMarch 2015

Discussed broad concepts during RTP meetings

May-August 2016

Final guidance Issued

January 2016

External review of draft guidance

EPA decisions on substance of guidance and drafting of guidance document

Sept-Nov 2015

2018-2021

SIP submissions


Please send any additional comments (by August 7) to [email protected]

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Appendix


Confidential and Deliberative – Do Not Share Beyond the Participating Federal, State, and Tribal Agencies

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RHR Tracking Metrics Framework - Decisions

2064 Endpoint

20% most

and least values

Sorting value

Natural Levels

General Haze

Sorting Concept

IMPROVE data

Impairment(Anthropogenic)

Estimate Daily values

(e3+Trijonis)

Impairment by Bext

Impaired DV 0 to 1

Total Bext Avg Natural Bext

Total DV Avg Natural DV

Impairment by DV

Impaired DV 0 to 1


Total DVEstimate

Episode values(e3)

DV with modified episodes


Documents

Tracking Visibility Progress in the Regional Haze Rule: Focusing the Reasonable Progress Framework on Controllable Emissions July 28 & 29, 2015 1:00 –