Review of New IMPROVE Review of New IMPROVE Extinction AlgorithmExtinction Algorithm

AoH Meeting – San DiegoAoH Meeting – San DiegoJanuary 24, 2006January 24, 2006

Joe Adlhoch - Air Resource Specialists, Inc.Joe Adlhoch - Air Resource Specialists, Inc.

OverviewOverview

Review of proposed changes to the Review of proposed changes to the IMPROVE extinction algorithmIMPROVE extinction algorithm

Size fractions for Size fractions for sulfate/nitrate/carbonsulfate/nitrate/carbon

Effect of sea saltEffect of sea salt Comparison of aerosol vs. measured Comparison of aerosol vs. measured

light scatteringlight scattering Comparison of old and new Comparison of old and new

algorithm for selected WRAP sitesalgorithm for selected WRAP sites

Old IMPROVE AlgorithmOld IMPROVE Algorithm

Assumptions include that • Six particle component terms plus a constant Rayleigh scattering term are sufficient for a good estimate of light extinction; • Constant dry extinction efficiency terms for each of the six particle components works adequately for all locations and times; and • Light extinction by the individual particle components can be adequately estimated as separate terms (like externally mixed components).

10

6.0

1

10

4

)(3

)(3

MassCoarse

SoilFine

CarbonElemental

CarbonOrganic

NitrateRHf

SulfateRHfbext

New or Revised TermsNew or Revised Terms

Variable extinction efficiencies and two Variable extinction efficiencies and two additional f(RH) terms for sulfate, nitrate, additional f(RH) terms for sulfate, nitrate, and organic mass – a mixture of small and and organic mass – a mixture of small and large particles is assumedlarge particles is assumed

Organic Compound Mass to Organic Carbon Organic Compound Mass to Organic Carbon Mass Ratio changed from 1.4 to 1.8 Mass Ratio changed from 1.4 to 1.8

Addition of Sea Salt = 1.8 x [Addition of Sea Salt = 1.8 x [ChlorideChloride] and ] and has its own water growth term fhas its own water growth term fSSSS(RH)(RH)

Rayleigh Scattering is calculated for the Rayleigh Scattering is calculated for the monitoring site elevation and annual mean monitoring site elevation and annual mean temperature and integer rounded. Ranges temperature and integer rounded. Ranges from 8 Mmfrom 8 Mm-1 -1 at 10,000’ to 12 Mmat 10,000’ to 12 Mm-1-1 at sea level at sea level

Addition of NOAddition of NO22 light absorption in the visible light absorption in the visible is included for sites that have such data (not is included for sites that have such data (not routinely available at IMPROVE sites)routinely available at IMPROVE sites)

where

and nitrate and organic are split using the same process

(ppb)NO0.33

Specific)iteS(ScatteringRayleigh

6.0

SaltSea(RH)f1.7

1

10

CarbonOrganicargeL6.1CarbonOrganicSmall2.8

NitrateargeL(RH)f5.1NitrateSmall(RH)f2.4

SulfateargeL(RH)f4.8SulfateSmall(RH)f2.2

2

SS

LS

LS

MassCoarse

SoilFine

CarbonElemental

bext

20,20

arg SulfateTotalforSulfateTotalSulfateTotal

SulfateeL

20,arg SulfateTotalforSulfateTotalSultateeL

SulfateeLSulfateTotalSulfateSmall arg

New IMPROVE AlgorithmNew IMPROVE Algorithm

Water Growth Curves

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9

10

0 10 20 30 40 50 60 70 80 90 100

Relative Humidity (%)

f(R

H)

fS(RH)

fL(RH)

Original

fSS(RH)

Relative Humidity Relative Humidity Enhancement FactorsEnhancement Factors

Large/Small Species FractionsLarge/Small Species Fractions

Ammonium sulfate, ammonium nitrate, and Ammonium sulfate, ammonium nitrate, and particulate organic matter are divided into particulate organic matter are divided into “Small” and “Large” fractions:“Small” and “Large” fractions: ““Small” fraction extinction efficiency less than half Small” fraction extinction efficiency less than half

that of “Large” fractionthat of “Large” fraction f(RH) for “Small” fraction slightly higherf(RH) for “Small” fraction slightly higher

““Small” fraction dominates mass up to about 5 Small” fraction dominates mass up to about 5 ug/mug/m33

““Large” fraction dominates mass above about Large” fraction dominates mass above about 12 ug/m12 ug/m33

Review of WRAP data shows that while high Review of WRAP data shows that while high concentrations do occur, nearly all samples of concentrations do occur, nearly all samples of these species are below 5 ug/mthese species are below 5 ug/m33

Large/Small Species SplitLarge/Small Species Split

Large/Small Ammonium Sulfate Split

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0 2 4 6 8 10 12 14 16 18 20 22 24

Total Ammonium Sulfate (ug/m3)

Lar

ge/S

mal

l Am

mon

ium

Su

lfat

e (u

g/m

3) Large Fraction

Small Fraction

Large fraction dominates

Small fraction dominates

Distribution of Sulfate Distribution of Sulfate ConcentrationsConcentrations

Distribution of Sulfate – Distribution of Sulfate – SequoiaSequoia

Distribution of Sulfate – Agua Distribution of Sulfate – Agua TibiaTibia

Distribution of Sulfate – Crater Distribution of Sulfate – Crater LakeLake

Distribution of Sulfate – Distribution of Sulfate – JarbidgeJarbidge

Distribution of Nitrate Distribution of Nitrate ConcentrationsConcentrations

Distribution of Nitrate – Distribution of Nitrate – SequoiaSequoia

Distribution of Nitrate – Agua Distribution of Nitrate – Agua TibiaTibia

Distribution of Nitrate – Crater Distribution of Nitrate – Crater LakeLake

Distribution of Nitrate – Distribution of Nitrate – JarbidgeJarbidge

Distribution of Organic Mass Distribution of Organic Mass Conc.Conc.

Distribution of OM – SequoiaDistribution of OM – Sequoia

Distribution of OM – Agua Distribution of OM – Agua TibiaTibia

Distribution of OM – Crater Distribution of OM – Crater LakeLake

Distribution of OM – JarbidgeDistribution of OM – Jarbidge

Review of IMPROVE Sea Salt Review of IMPROVE Sea Salt TermTerm

Sea salt estimated from Chloride ion Sea salt estimated from Chloride ion measurement, Chlorine can be used as measurement, Chlorine can be used as a back upa back up

Review of 2004 data shows significant Review of 2004 data shows significant effect only at coastal siteseffect only at coastal sites

Review of 2000 – 2004 data timelines Review of 2000 – 2004 data timelines shows problems with Chloride shows problems with Chloride measurements prior to 2004, but measurements prior to 2004, but Chlorine appears to be a reliable back Chlorine appears to be a reliable back upup

Annual Avg. Chloride Mass, Annual Avg. Chloride Mass, 20042004

Chloride/Chlorine Mass Chloride/Chlorine Mass TimelinesTimelines

Baseline\2004: median UNC ~ 0.04\0.006; median MDL ~ 0.07\0.01

Baseline: median UNC ~ <0.001; median MDL ~ 0.001

Chloride/Chlorine Mass Chloride/Chlorine Mass TimelinesTimelines

Baseline\2004: median UNC ~ 0.04\0.006; median MDL ~ 0.07\0.01

Baseline: median UNC ~ <0.001; median MDL ~ 0.001

Chloride/Chlorine Mass Chloride/Chlorine Mass TimelinesTimelines

Baseline\2004: median UNC ~ 0.08\0.05; median MDL ~ 0.07\0.01

Baseline: median UNC ~ <0.03; median MDL ~ 0.001

Estimated vs. Measured Light Estimated vs. Measured Light ScatteringScattering

Nephelometers provide a direct measurement of Nephelometers provide a direct measurement of particle light scattering (extinction without particle light scattering (extinction without elemental carbon absorption and Rayleigh elemental carbon absorption and Rayleigh scattering terms)scattering terms)

Comparison of estimated (aerosol) vs. measured Comparison of estimated (aerosol) vs. measured (nephelometer) scattering possible at many (nephelometer) scattering possible at many IMPROVE sitesIMPROVE sites

Typically, the Old IMPROVE equation Typically, the Old IMPROVE equation underestimates extinction on very dirty days and underestimates extinction on very dirty days and overestimates extinction on very clean daysoverestimates extinction on very clean days

At most sites the New equation reduces this bias, At most sites the New equation reduces this bias, though network-wide there is additional uncertaintythough network-wide there is additional uncertainty Change more dramatic with dirtier sitesChange more dramatic with dirtier sites Urban site (Phoenix) shows significant deviation from 1 to 1 Urban site (Phoenix) shows significant deviation from 1 to 1

line, may be due to poor characterization of urban haze, line, may be due to poor characterization of urban haze, influence of NOinfluence of NO22, or measurement errors, or measurement errors

Following slides taken from work done by NPSFollowing slides taken from work done by NPS

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Measured Bsp

IMP

RO

VE

Bsp

Old IMPROVE Algorithm: Estimated vs. Observed Old IMPROVE Algorithm: Estimated vs. Observed Light Scattering for 21 Nephelometer Monitoring Light Scattering for 21 Nephelometer Monitoring

SitesSites

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Measured Bsp

Sp

lit C

om

po

nen

t M

eth

od

Bsp

New IMPROVE Algorithm: Estimated vs. Observed New IMPROVE Algorithm: Estimated vs. Observed Light Scattering for 21 Nephelometer Monitoring Light Scattering for 21 Nephelometer Monitoring

SitesSites

Site Comparison – Grand Site Comparison – Grand CanyonCanyon

▲▲ Old Equ.

●● New Equ.

Grand Canyon

Site Comparison – GilaSite Comparison – Gila

▲▲ Old Equ.

●● New Equ.

Gila

Site Comparison – Great Site Comparison – Great Smoky Mtns.Smoky Mtns.

▲▲ Old Equ.

●● New Equ.

Great Smoky Mtns.

Site Comparisons – Pacific Site Comparisons – Pacific NorthwestNorthwest

Snoqualmie Pass

Mt. Rainier

Columbia River Gorge

Three Sisters

Site Comparisons – SouthwestSite Comparisons – Southwest

Sycamore Canyon

Ike’s Backbone

Phoenix Big Bend

Site Comparisons – CentralSite Comparisons – Central

Jarbidge Lone Peak

Summary of New AlgorithmSummary of New Algorithm The New algorithm incorporates new terms to The New algorithm incorporates new terms to

more completely account for haze, incorporates more completely account for haze, incorporates updated information, and reduces know biasesupdated information, and reduces know biases

Performance tests of the New algorithm showPerformance tests of the New algorithm show it reduces bias compared to the Old algorithm at the it reduces bias compared to the Old algorithm at the

extremes extremes it has as somewhat greater uncertainty that causes it has as somewhat greater uncertainty that causes

it to mis-select hazy days a little more frequentlyit to mis-select hazy days a little more frequently little sensitivity to which algorithm is used with little sensitivity to which algorithm is used with

regards to composition on the extreme daysregards to composition on the extreme days Following slides illustrate the difference Following slides illustrate the difference

between the 20% worst/best days calculated between the 20% worst/best days calculated with the Old and New algorithm for selected with the Old and New algorithm for selected sitessites

Class I and Other IMPROVE

Monitoring Locations

N on-C lass I A rea

Class I A rea

AG TI1

BAD L1

BAN D 1

BLIS1

BO AP1

BR C A1

BR ID 1

BR LA1

C ABI1

C AN Y1C API1

C H IR 1

C LPE1

C O G O 1 C O R I1

C R LA1C R M O 1

D EVA1D O M E1

FLAT1

FO PE1G AM O 1

G IC L1

G LAC 1

G R BA1

G R C A2

G R SA1

G U M O 1

H EC A1

H ILL1

H O O V1

IKBA1

JAR B1

JO SH 1

KAIS1

KALM 1

LABE1

LAVO 1

LO ST1M ELA1

M EVE1

M O H O 1

M O N T1

M O R A1

M O ZI1

N O AB1

N O C A1

N O C H 1

O LYM 1

O R PI1

PASA1

PEFO 1

PIN N 1

PO R E1

Q U VA1

R AFA1

R ED W 1

R O M O 1

SAC R 1

SAG A1SAG O 1

SAG U 1

SAPE1

SAW E1

SAW T1

SEQ U 1

SIAN 1

SN PA1 SPO K1

STAR 1 SU LA1

SYC A1

TH BA1

TH R O 1TH SI1

TO N T1

TR IN 1

U LBE1

W EM I1

W H IT1

W H PA1

W H PE1

W H R I1

W IC A1

YELL2

YO SE1

ZIO N 1

D EN A1

TR C R 1TU XE1

H ALE1

H AVO 1

SIM E1

Selected Monitoring LocationsSelected Monitoring Locations

Comparison – 20% Worst Days, Comparison – 20% Worst Days, 20022002

Light Extinction Budget for 20% Worst Days in 2002(Existing IMPROVE Equ. - left; Proposed Equ. - right)

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Olympic Mount Rainier Redwood Agua Tibia

Lig

ht

Ext

inct

ion

(M

m-1

) ESea_Salt

ECM

ESoil

ELAC

EOMC

EAmm_NO3

EAmm_SO4

Rayleigh

Comparison – 20% Worst Days, Comparison – 20% Worst Days, 20022002

Light Extinction Budget for 20% Worst Days in 2002(Existing IMPROVE Equ. - left; Proposed Equ. - right)

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Badlands Bridger Canyonlands Salt Creek

Lig

ht

Ext

inct

ion

(M

m-1

) ESea_Salt

ECM

ESoil

ELAC

EOMC

EAmm_NO3

EAmm_SO4

Rayleigh

Comparison – 20% Best Days, Comparison – 20% Best Days, 20022002

Light Extinction Budget for 20% Best Days in 2002(Existing IMPROVE Equ. - left; Proposed Equ. - right)

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Olympic Mount Rainier Redwood Agua Tibia

Lig

ht

Ext

inct

ion

(M

m-1

) ESea_Salt

ECM

ESoil

ELAC

EOMC

EAmm_NO3

EAmm_SO4

Rayleigh

Comparison – 20% Best Days, Comparison – 20% Best Days, 20022002

Light Extinction Budget for 20% Best Days in 2002(Existing IMPROVE Equ. - left; Proposed Equ. - right)

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25

Badlands Bridger Canyonlands Salt Creek

Lig

ht

Ext

inct

ion

(M

m-1

) ESea_Salt

ECM

ESoil

ELAC

EOMC

EAmm_NO3

EAmm_SO4

Rayleigh

Implementation Steps forImplementation Steps forRegional Haze Rule Regional Haze Rule

ApplicationApplication IMPROVE Steering Committee has approved IMPROVE Steering Committee has approved

(12/05)(12/05) Calculation of water growth functions for Calculation of water growth functions for

monthly & annual averaged conditions for monthly & annual averaged conditions for each monitoring site has been completed each monitoring site has been completed (01/06)(01/06)

Recalculation of current (5-year baseline) and Recalculation of current (5-year baseline) and natural haze levels – VIEWS – by March ???natural haze levels – VIEWS – by March ???

EPA modifies the regional haze guidance, so EPA modifies the regional haze guidance, so states can choose – 6 to 12 monthsstates can choose – 6 to 12 months

VIEWS will support both versions of the VIEWS will support both versions of the algorithm for the foreseeable futurealgorithm for the foreseeable future