Natural Background Visibility

1
Natural Background Visibility and Reasonable
Progress Goals
STAD Presentation December 14, 2004 Pat Brewer,
Ivar Tombach, Scott Reynolds
Sunrise, Charleston Harbor
2
Draft 12/03/04
VISTAS Deliverables to State Implementation
Plans for Regional Haze
Observations, Conclusions, Recommendations Dec
04 - Dec 05
Natural Visibility and Reasonable Progress
Goals Dec 04 Jun 05
Visibility PM2.5 Trends
Site-Specific Descriptions Dec 04 Aug 05
Public Consultation 2005-2007
Conceptual Description
Select Episodes Spring 05
Characterize Meteorology
Guidance to State Planning for Regional Haze
Dec 2005
Control Strategy Inventories Feb 05 May 05
Utility Forecast 2009-2018 Dec 04
Emissions Inventories 2002, 2009, 2018
Reports and SIP Appendices 2006
AQ Model Runs 2002, 2009, 2018 Dec 04 - Mar 05
Control Strategy AQ Modeling May 05 - Aug 05
Met, Em, and AQ Model protocol performance
Control Strategy Design Dec 04 - May 05
Economic Analyses Sep 2005
State Regulatory Decisions
Emission Sensitivities
Identify BART sources and control options
BART modeling protocol impacts Dec 04 - Oct 05
BART control evaluation Jan Jun 05
BART controls 2005-2007
Inter-RPO-State 2005-2007
3
Light Extinction on 20 Haziest Days - IMPROVE
2000 - 2002
250
200
CM
Soil
150
Organics
EC
Extinction (Mm-1)
NH4NO3
100
(NH4)2SO4
Rayleigh
50
0
Cadiz, KY
Sipsey, AL
Saint Marks, FL
Dolly Sods, WV
Everglades, FL
Shenandoah, VA
Okefenokee, GA
Linville Gorge, NC
Swan Quarter, NC
Shining Rock, NC
Cape Romain, SC
Mammoth Cave, KY
Chassahowitzka, FL
James Rvier Face, VA
Great Smoky Mtns, TN
4
Light Extinction on 20 Clearest Days - IMPROVE
2000 - 2002
CM
Soil
Organics
Extinction (Mm-1)
EC
NH4NO3
(NH4)2SO4
Rayleigh
Cadiz, KY
Sipsey, AL
Saint Marks, FL
Dolly Sods, WV
Everglades, FL
Shenandoah, VA
Okefenokee, GA
Linville Gorge, NC
Swan Quarter, NC
Shining Rock, NC
Cape Romain, SC
Mammoth Cave, KY
Chassahowitzka, FL
James Rvier Face, VA
Great Smoky Mtns, TN
5
Current vs Natural Background Visibility
Coarse
Soil
Elem Carbon
Organic Mass
Amm Nitrate
Amm Sulfate
Rayleigh
1998-2002
1998-2002
1999-2002
1999-2002
Annual
Annual
Average
20 Haziest
20
20 Haziest
20
Average
Natural
Cleanest
Cleanest
Natural
Background
Background
Great Smoky Mtn.
Cape Romain
6
Calculating Light Extinction IMPROVE Equation

• Calculate reconstructed extinction (Bext) from
  IMPROVE chemical composition data
• Bext 3 f(RH) Ammonium Sulfate
• 3 f(RH) Ammonium Nitrate
• 4 1.4 x Organic Carbon
• 1 Soil
• 0.6 Coarse Mass
• 10 Elemental Carbon
• 10 (Rayleigh Scattering)
• Calculate deciviews (dv) dv 10 ln (Bext/10)
• 20 Worst (dv) Annual Average (dv) 1.28x 3
  dv (for sites in East)

7
Natural Background Visibility Policy
Considerations

• VISTAS assumptions must be comparable to EPA and
  other RPOs
• Retain defaults
• Identify alternative ranges for each Class I area
  in southeastern US
• Alternative assumptions for natural background
  concentrations
• Alternative assumptions for extinction efficiency
  coefficients used in IMPROVE equation
• Do changes in assumptions for 2064 affect
  reasonable progress goals for 2018?

8
EPAs Default Natural Conditions for Eastern US
1 Trijonis, et al, 1990. National Acid
Precipitation Assessment Program, State of
Science Report 24.
9
Issues with Default Concentrations

• Concentration estimates are very approximate
• More recent data for organic carbon, fine soil,
  intercontinental transported pollutants
• Fine sea salt is not included
• Same concentrations are assumed at all Class I
  areas in the East
• Same concentrations are assumed to occur every
  month of the year
• 20 haziest days are assumed to be represented by
  the 90th percentile

10
Natural Background Visibility Potential Changes
to Default Concentrations for VISTAS Class I Areas
Includes assumptions from SEARCH
11
EPA Default Glidepath vs Alternative
Calculations 20 Haziest Days
20 Haziest Days
29.9
Incremental Change
dV
Natural Background (with alternative
assumptions)
Natural Background (EPA default)
2000 2018 YEAR
2064
12
Consider Natural Organic Carbon emissions for
heavily forested areas
13
Calculating Annual Average Natural Background
Visibility Great Smoky Mtns. and Cape Romain
14
Consider Haze from Seasalt at coastal sites
15
Calculating Annual Average Natural Background
Visibility Great Smoky Mtns. and Cape Romain
16
Calculating Natural Background Visibility for 20
Worst Days Great Smoky Mtns. and Cape Romain
Natural Background Visibility (20 worst using
92nd ile)
16.00
14.00
12.00
10.00
Haze Index (dv)
8.00
6.00
4.00
2.00
0.00
GRSM1
GRSM2
GRSM3
ROMA1
ROMA2
ROMA3
ROMA4
ROMA5
Biogenic
Oceanic
Default
2.1xOC
Default
2.1xOC
Sea Salt
African Dust
OCM
OCM
17
Reasonable Progress Glide Path for 20 haziest
days Great Smoky Mountains
35
30
Haze Index (dv)
25
20
15
10
2000
2010
2020
2030
2040
2050
2060
2070
Year
GRSM3 Biogenic OC
GRSM1 Default
GRSM2 2.1xOC
18
Reasonable Progress Glide Path for 20 haziest
days Cape Romain
30
25
Haze Index (dv)
20
15
10
2000
2010
2020
2030
2040
2050
2060
2070
Year
ROMA1 Default
ROMA3 Sea Salt
ROMA2 2.1xOC
ROMA4 Oceanic OC
19
Implications at Great Smoky Mtns. And Cape Romain
20
Natural Background Visibility Potential Changes
to Default Calculations for VISTAS Class I Areas
21
Natural Conditions EPRI Alternative

• Increase Organic Carbon Mass Multiplier from 1.4
  to 2.0
• To retain calculated extinction comparable to
  extinction measured using nephelometer
• Allow extinction coefficients for S and N to vary
  with mass (more efficient scattering with
  increased mass)
• Reduce coefficient for OC

22
Calculated vs Measured Light Extinction - Mammoth
Cave 2000 - 2003
IMPROVE equation
EPRI assumptions
23
Calculated vs Measured Light Extinction -
Shenandoah 2000 - 2003
IMPROVE equation
EPRI assumptions
24
Calculated vs Measured Light Extinction Great
Smoky Mtns. 2000 - 2003
IMPROVE equation
EPRI assumptions
25
Estimated Annual Average Natural Extinction
30
25
20
15
Extinction (Mm-1)
10
5
0
EPA Default
Default
Default
EPA Default
Default
Default
2.1xOM
2.1xOM
2.1xOM
2.1xOM
revised
revised
bext
bext
Great Smoky Mtns. Cape
Romain, SC
26
Alternative Glidepath Great Smoky MTN.
Glide Path to Natural Condions (2004-2064)
GRSM Average Haziest Days
5Yr rolling Avg
25
DEFAULT ASSUMPTIONS
GRSM - 2.1xOM
GRSM - 2.1xOM revised bext
GRSM 2.1xOM 4 OC
20
Deciviews (dv)
15
10
5
0
2004
2008
2012
2016
2020
2024
2028
2032
2036
2040
2044
2048
2052
2056
2060
2064
1988-1992
1992-1996
1996-2000
27
EPA Default Glidepath vs Alternative
Calculations 20 Haziest Days
20 Haziest Days
29.9
Incremental Change
Added increment due to emissions from outside US
dV
Natural Background (with alternative
assumptions)
Natural Background (EPA default)
2000 2018 YEAR
2064
28
Sulfate-Nitrate-Ammonium Aerosol from GEOS-CHEM
Modeling
Amm. nitrate (mg m-3) East
Amm. sulfate (mg m-3) East
3.26
4.11
Baseline (2001)
0.37/0.03 0.1
0.38/0.11 0.23

• GEOS-CHEM - No anthropogenic. emissions in US
  /globally
• EPA default values

0.25 -0.02
0.14 0.12

Contributions from trans-boundary anthropogenic.
sources Canada and Mexico Asia

• Achievability of EPA default estimates is
  compromised by transboundary pollution influences
• Transboundary sulfate influence from Asia is
  comparable in magnitude to that from Canada
  Mexico

29
Carbonaceous Aerosol from GEOS-CHEM Modeling
EC (mg m-3 ) East
OC (mg m-3) East
0.68
3.2
Baseline (1998)
0.02 0.02
1.1 1.4

• No anthropogenic emissions in U.S.
• GEOS-CHEM (w/ climatological fires)
• EPA default values

0.02 0.003
0.05 0.007


Contributions from transboundary anthropogenic
sources (excluding fires) Canada and Mexico Asia
This includes anthropogenic vegetation burning,
however.

• Model indicates that EPA default natural
  concentrations are too low by factors of 2-3
  except for OC and EC in Eastern U.S.
  quantifying fire influences is critical
• Transboundary pollution influences are
  relatively small compared to EPA default natural
  concentrations, except for EC from Canada/Mexico

30
EPA Default Glidepath vs Alternative
Calculations 20 Haziest Days
20 Haziest Days
29.9
Incremental Change
Added increment due to emissions from outside US
dV
Natural Background (with alternative
assumptions)
Natural Background (EPA default)
2000 2018 YEAR
2064
31
Natural Background Visibility Credible
alternatives to EPA default assumptions show
little difference to slope of glidepath for
reasonable progress in 2018.
Cold Mountain, Shining Rock Wilderness Area
32
Reasonable Progress Glide Path for 20 haziest
days
33
EPA Default Glidepath vs Alternative
Calculations 20 Haziest Days
20 Haziest Days
29.9
Incremental Change
Added increment due to emissions from outside US
dV
Natural Background (with alternative
assumptions)
Natural Background (EPA default)
2000 2018 YEAR
2064
34
Draft 12/03/04
VISTAS Deliverables to State Implementation
Plans for Regional Haze
Observations, Conclusions, Recommendations Dec
04 - Dec 05
Natural Visibility and Reasonable Progress
Goals Dec 04 Jun 05
Visibility PM2.5 Trends
Site-Specific Descriptions Dec 04 Aug 05
Public Consultation 2005-2007
Conceptual Description
Select Episodes Spring 05
Characterize Meteorology
Guidance to State Planning for Regional Haze
Dec 2005
Control Strategy Inventories Feb 05 May 05
Utility Forecast 2009-2018 Dec 04
Emissions Inventories 2002, 2009, 2018
Reports and SIP Appendices 2006
AQ Model Runs 2002, 2009, 2018 Dec 04 - Mar 05
Control Strategy AQ Modeling May 05 - Aug 05
Met, Em, and AQ Model protocol performance
Control Strategy Design Dec 04 - May 05
Economic Analyses Sep 2005
State Regulatory Decisions
Emission Sensitivities
Identify BART sources and control options
BART modeling protocol impacts Dec 04 - Oct 05
BART control evaluation Jan Jun 05
BART controls 2005-2007
Inter-RPO-State 2005-2007