Natural Haze Levels II:

Application of the New IMPROVE 

Algorithm to Natural Species 

Concentrations Estimates

Final Report by the 

Natural Haze Levels II Committee to the 

RPO Monitoring/Data Analysis Workgroup
Note: This presentation contains substantial additional information in the notes 

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“Print”). You can also use “Preview” for the “Notes Pages” to more easily read 

the notes on your computer monitor.

These notes were prepared 

1. to aid those hearing the presentation by relieving them of the burden of taking 

as many notes; 

2. to allow those who haven’t heard the presentation to understand it by providing 

the additional information that is spoken during presentations; and 

3. to provide a more complete documentation of the natural haze levels II 

approach for anyone who may want to understand it

For additional information contact Marc Pitchford at Marc.Pitchford@NOAA.gov
Overall Goal

• Estimate 20% best and 20% worst natural haze 

levels for visibility-protected class I areas using 

the new IMPROVE algorithm for estimating light 

extinction from aerosol species concentrations.

– Needed for Regional Haze Rule (RHR) rate of progress 

glide slopes where the new IMPROVE algorithm is 

used to characterize current haze levels

– Should minimize the technical problems identified in 

the RHR default natural haze levels that were 

developed using the original IMPROVE algorithm 
Default Natural Haze Levels Approach

• Typical haze level estimates for East and West 

– Typical light extinction by applying the original 

IMPROVE algorithm to Trijonis natural species 

concentration estimates for East and West

– Convert to haze index (deciview units)

• 20% best and 20% worst haze estimate for East 

and West

– Best = typical – 1.28(standard deviation)

– Worst = typical + 1.28(standard deviation)

– Standard deviation is 3dv for the East and 2dv for the 

West (corresponds to the 10th and 90th percentile)
Criticism of the Default Approach

• Limitations of the original IMPROVE algorithm 

– Biased light extinction estimates at the extremes

– Uses an outdated organic compound mass to carbon 

mass ratio

– No sea salt (important at a few sites)

– Rayleigh scattering of 10Mm-1 used for all site

• Flawed assumptions used to estimate 20% best 

and worst conditions

– Haze index for natural conditions are not likely to be 

normally distributed due to inclusion of Rayleigh 

scattering 

– 10th and 90th percentiles don’t correspond to the best 

and worst conditions if the distribution were normal
Natural Haze Levels II Approach

• Adjust each of the measured major species 

concentrations to the Trijonis natural concentration 

estimates 

– Multiply each species concentration at a site by the sitespecific ratio of the (Trijonis natural estimate) divided by the 

(annual mean concentration) for the species for the 5 year 

baseline period

– If the annual mean concentration for a species is smaller than 

the Trijonis natural estimate, make no adjustment

– Current sea salt levels are taken to be natural levels

• Apply the new IMPROVE algorithm to the Trijonisadjusted species concentrations at each site to produce 

a distribution of natural light extinction values

• Convert to deciview and calculate the mean of the 20% 

best and 20% worst haze levels
Trijonis-Adjusted Specie Frequency Distributions

•Sipsey Alabama

•Each aerosol species 

mass concentration 

frequency distribution 

scaled to estimated natural 

mass concentrations

•If current species mean is 

less than natural estimate, 

the that species is not 

scaled

•Geometric shape of 

species distributions is 

unchanged

Current 2000-2004

Natural Estimate

Hanging bars

Solid - current mean

Dashed - natural estimate mean
Current and Natural Haze Frequency Distributions

• Sipsey Alabama

• Natural scenario joint distribution shape is derived from scaling current 

aerosol species mass concentrations to natural condition estimates

• Allows estimation of best and worst 20% dv or aerosol species 

extinction
Natural Haze Levels II
Default Natural Haze Levels
Natural Haze Levels II, 

10-Year Rate of Progress Glide Path
Default Natural Haze Levels, 

10-Year Rate of Progress Glide Path
Status and Next Steps

• This presentation is the final report of the Natural 

Haze Levels II Committee of the RPO 

Monitoring/Data Analysis Workgroup

• Review comments received by August 25, 2006 

will be considered in preparation of the RPO 

Monitoring/Data Analysis Workgroup approved 

approach

• Workgroup approved approach is forwarded to the 

RPOs for their consideration by August 31, 2006

• This presentation, including the natural haze 

estimates and any modifications will be made 

available on VIEWS 
Appendix

• Tables of Natural Haze Level II Estimates 

for all IMPROVE Sites by RPO and State
Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

CACR1 Caney Creek Arkansas 3 11.7 26.4 2.4 Caney Creek

UPBU1 Upper Buffalo Wilderness Arkansas 5 11.7 26.3 2.4 Upper Buffalo

BRET1 Breton* Louisiana 4 12.3 0.0 0.0 Breton

BOWA1 Boundary Waters Canoe Area Minnesota 2 11.6 20.0 1.4 Boundary Waters Canoe Area

VOYA2 Voyageurs NP #2 Minnesota 5 12.2 19.3 1.2 Voyageurs

HEGL1 Hercules-Glades Missouri 3 11.4 26.7 2.6 Hercules-Glade

MING1 Mingo Missouri 1 12.5 29.5 2.8 Mingo

WIMO1 Wichita Mountains Oklahoma 3 7.6 23.8 2.7 Wichita Mountains

BIBE1 Big Bend NP Texas 4 7.2 17.3 1.7 Big Bend

GUMO1 Guadalupe Mountains NP Texas 5 6.8 17.2 1.7 Guadalupe Mountains; Carlsbad Caverns

CENRAP

MANE-VU & Midwest RPO

Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

ACAD1 Acadia NP Maine 5 12.5 22.9 1.7 Acadia

MOOS1 Moosehorn NWR Maine 5 12.1 21.7 1.6 Moosehorn; Roosevelt Campobello

GRGU1 Great Gulf Wilderness

New 

Hampshire 4 12.1 22.8 1.8

Great Gulf; Presidential Range-Dry

River

BRIG1 Brigantine NWR New Jersey 5 12.3 29.0 2.8 Brigantine

LYBR1 Lye Brook Wilderness Vermont 5 11.9 24.4 2.1 Lye Brook

ISLE1 Isle Royale NP Michigan 5 12.5 20.7 1.4 Isle Royale

SENE1 Seney Michigan 5 12.8 24.2 1.9 Seney
Site Name State

Complet

e Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide Slope 

(dv) Class I Area(s)

SIPS1 Sipsy Wilderness Alabama 4 11.1 29.0 3.0 Sipsey

CHAS1 Chassahowitzka NWR Florida 3 11.3 26.1 2.5 Chassahowitzka

EVER1 Everglades NP Florida 4 12.3 22.3 1.7 Everglades

SAMA1 St. Marks Florida 2 11.6 26.0 2.4 Saint Marks

COHU1 Cohutta Georgia 2 11.2 30.3 3.2 Cohutta

OKEF1 Okefenokee NWR Georgia 5 11.5 27.1 2.6 Okefenokee; Wolf Island

MACA1 Mammoth Cave NP Kentucky 5 11.2 31.4 3.4 Mammoth Cave

LIGO1 Linville Gorge

North 

Carolina 4 11.3 28.8 2.9 Linville Gorge

SHRO1 Shining Rock Wilderness

North 

Carolina 2 11.6 27.9 2.7 Shining Rock

SWAN1 Swanquarter

North 

Carolina 2 12.0 25.5 2.2 Swanquarter

ROMA1 Cape Romain NWR

South 

Carolina 5 12.2 26.5 2.4 Cape Romain

GRSM1 Great Smoky Mountains NP Tennessee 5 11.3 30.3 3.2

Great Smoky Mountains; Joyce 

Kilmer-Slickrock

JARI1 James River Face Wilderness Virginia 4 11.2 29.1 3.0 James River Face

SHEN1 Shenandoah NP Virginia 5 11.4 29.3 3.0 Shenandoah

DOSO1 Dolly Sods Wilderness West Virginia 5 10.4 29.0 3.1 Dolly Sods; Otter Creek

VIIS1 Virgin Islands NP Virgin Islands 4 10.8 17.0 1.0 Virgin Islands

VISTAS + VI
Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

DENA1 Denali NP Alaska 5 7.4 9.9 0.4 Denali

SIME1 Simeonof Alaska 3 15.7 18.6 0.5 Simeonof

TUXE1 Tuxedni Alaska 3 11.5 14.1 0.4 Tuxedni

BALD1 Mount Baldy Arizona 2 6.6 11.5 0.8 Mount Baldy

CHIR1 Chiricahua NM Arizona 5 7.3 13.4 1.0

Chiricahua NM; Chiricahua W; 

Galiuro

GRCA2 Hance Camp at Grand Canyon NP Arizona 4 7.2 11.7 0.7 Grand Canyon

IKBA1 Ike's Backbone Arizona 4 6.7 13.3 1.1 Mazatzal; Pine Mountain

PEFO1 Petrified Forest NP Arizona 5 6.6 13.2 1.1 Petrified Forest

SAGU1 Saguaro NM Arizona 3 6.5 14.8 1.4 Saguaro

SIAN1 Sierra Ancha Arizona 4 6.7 13.7 1.2 Sierra Ancha

SYCA1 Sycamore Canyon Arizona 4 6.8 15.3 1.4 Sycamore Canyon

TONT1 Tonto NM Arizona 3 6.7 13.9 1.2 Superstition

WRAP
Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

AGTI1 Agua Tibia California 4 7.7 23.5 2.6 Agua Tibia

BLIS1 Bliss SP (TRPA) California 4 6.2 12.6 1.1 Desolation; Mokelumne

DOME1 Dome Lands Wilderness California 4 7.5 19.4 2.0 Dome Land

HOOV1 Hoover California 3 8.0 12.9 0.8 Hoover

JOSH1 Joshua Tree NP California 4 7.3 19.6 2.1 Joshua Tree

KAIS1 Kaiser California 2 7.3 14.8 1.2 Ansel Adams; Kaiser; John Muir

LABE1 Lava Beds NM California 4 7.9 15.1 1.2 Lava Beds; South Warner

LAVO1 Lassen Volcanic NP California 5 7.4 14.1 1.1

Lassen Volcanic; Caribou; 

Thousand Lakes; Caribou; 

Thousand Lakes

PINN1 Pinnacles NM California 4 8.1 18.5 1.7 Pinnacles; Ventana

PORE1 Point Reyes National Seashore California 3 15.9 22.8 1.2 Point Reyes

RAFA1 San Rafael California 2 7.8 18.9 1.8 San Rafael

REDW1 Redwood NP California 5 14.0 18.5 0.7 Redwood

SAGA1 San Gabriel California 3 7.1 19.9 2.1 San Gabriel; Cucamonga

SAGO1 San Gorgonio Wilderness California 4 7.4 22.2 2.5 San Gorgonio; San Jacinto

SEQU1 Sequoia NP California 3 7.6 24.6 2.8 Sequoia; Kings Canyon

TRIN1 Trinity California 3 8.3 16.3 1.3

Marble Mountain; Yolla Bolly-Middle 

Eel

YOSE1 Yosemite NP California 5 7.7 17.6 1.7 Yosemite; Emigrant

WRAP
Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

GRSA1 Great Sand Dunes NM Colorado 5 6.7 12.8 1.0 Great Sand Dunes

MEVE1 Mesa Verde NP Colorado 5 6.9 13.0 1.0 Mesa Verde

MOZI1 Mount Zirkel Wilderness Colorado 4 6.6 10.5 0.7 Mount Zirkel; Rawah

ROMO1 Rocky Mountain NP Colorado 5 7.3 13.8 1.1 Rocky Mountain

WEMI1 Weminuche Wilderness Colorado 4 6.3 10.3 0.7

La Garita; Black Canyon of the Gunnison; 

Weminuche

WHRI1 White River NF Colorado 4 6.7 9.6 0.5

Flat Tops; Maroon Bells-Snowmass; West 

Elk; Eagles Nest

HALE1 Haleakala NP Hawaii 4 7.5 13.3 1.0 Haleakala

HAVO1 Hawaii Volcanoes NP Hawaii 4 7.2 18.9 1.9 Hawaii Volcanoes

CRMO1 Craters of the Moon NM Idaho 4 7.6 14.0 1.1 Craters of the Moon

SAWT1 Sawtooth NF Idaho 4 6.5 13.8 1.2 Sawtooth

CABI1 Cabinet Mountains Montana 4 7.6 14.1 1.1 Cabinet Mountains

GAMO1 Gates of the Mountains Montana 4 6.5 11.3 0.8 Gates of the Mountains

GLAC1 Glacier NP Montana 3 9.1 20.5 1.9 Glacier

MELA1 Medicine Lake Montana 5 8.0 17.7 1.6 Medicine Lake

MONT1 Monture Montana 4 7.8 14.5 1.1

Bob Marshall; Mission Mountains; 

Scapegoat

SULA1 Sula Peak Montana 4 7.5 13.4 1.0 Selway-Bitterroot; Anaconda-Pintler

ULBE1 UL Bend Montana 4 8.2 15.1 1.1 UL Bend

WRAP
Site Name State

Complete 

Years

Worst 

Haze 

Natural II 

(dv)

Worst 

Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

JARB1 Jarbidge Wilderness Nevada 4 8.0 12.1 0.7 Jarbidge

BAND1 Bandelier NM

New 

Mexico 5 6.3 12.2 1.0 Bandelier

BOAP1 Bosque del Apache

New 

Mexico 3 6.8 13.8 1.2 Bosque del Apache

GICL1 Gila Wilderness

New 

Mexico 4 6.8 13.1 1.1 Gila

SACR1 Salt Creek

New 

Mexico 4 6.9 18.0 1.9 Salt Creek

SAPE1 San Pedro Parks

New 

Mexico 4 6.2 10.2 0.7 San Pedro Parks

WHIT1 White Mountain

New 

Mexico 3 6.9 13.7 1.1 White Mountain

WHPE1 Wheeler Peak

New 

Mexico 3 6.6 10.4 0.6 Wheeler Peak; Pecos

LOST1 Lostwood

North 

Dakota 5 8.1 19.6 1.9 Lostwood

THRO1 Theodore Roosevelt

North 

Dakota 4 7.9 17.7 1.6 Theodore Roosevelt

CRLA1 Crater Lake NP Oregon 3 8.0 13.7 1.0

Gearhart Mountain; Crater Lake; Diamond 

Peak; Mountain Lakes

HECA1 Hells Canyon Oregon 3 8.4 18.6 1.7 Hells Canyon

KALM1 Kalmiopsis Oregon 4 9.5 15.5 1.0 Kalmiopsis

MOHO1 Mount Hood Oregon 4 8.5 14.9 1.1 Mount Hood

STAR1 Starkey Oregon 4 9.0 18.6 1.6 Eagle Cap; Strawberry Mountain

THSI1 Three Sisters Wilderness Oregon 5 8.9 15.3 1.1

Three Sisters; Mount Jefferson; Mount 

Washington

WRAP
Site Name State

Complete 

Years

Worst Haze 

Natural II 

(dv)

Worst Haze 

Baseline 

(dv)

10-year 

Glide 

Slope (dv) Class I Area(s)

BADL1 Badlands NP

South 

Dakota 5 8.1 17.1 1.5 Badlands

WICA1 Wind Cave

South 

Dakota 5 7.8 15.8 1.3 Wind Cave

BRCA1 Bryce Canyon NP Utah 5 7.0 11.6 0.8 Bryce Canyon

CANY1 Canyonlands NP Utah 5 6.5 11.2 0.8 Canyonlands; Arches

CAPI1 Capitol Reef NP Utah 2 5.7 10.0 0.7 Capitol Reef

ZION1 Zion Utah 3 7.1 13.2 1.0 Zion

MORA1 Mount Rainier NP Washington 4 8.6 18.2 1.6 Mount Rainier

NOCA1 North Cascades Washington 2 8.1 14.0 1.0 North Cascades; Glacier Peak

OLYM1 Olympic Washington 3 8.5 16.7 1.4 Olympic

PASA1 Pasayten Washington 4 8.4 15.2 1.1 Pasayten

SNPA1 Snoqualmie Pass Washington 4 8.5 17.8 1.6 Alpine Lakes

WHPA1 White Pass Washington 4 8.5 12.8 0.7 Mount Adams; Goat Rocks

BRID1 Bridger Wilderness Wyoming 5 6.7 11.1 0.7 Bridger; Fitzpatrick

NOAB1 North Absaroka Wyoming 3 6.9 11.5 0.8 North Absaroka; Washakie

YELL2 Yellowstone NP 2 Wyoming 5 6.6 11.8 0.9

Yellowstone; Red Rock Lakes; Grand 

Teton; Teton

WRAP