review of new improve extinction algorithm aoh meeting – san diego january 24, 2006
DESCRIPTION
Review of New IMPROVE Extinction Algorithm AoH Meeting – San Diego January 24, 2006. Joe Adlhoch - Air Resource Specialists, Inc. Overview. Review of proposed changes to the IMPROVE extinction algorithm Size fractions for sulfate/nitrate/carbon Effect of sea salt - PowerPoint PPT PresentationTRANSCRIPT
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
0
1
2
3
4
5
6
7
8
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
0
5
10
15
20
25
30
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
0
50
100
150
200
250
300
350
0 50 100 150 200 250 300 350
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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50
100
150
200
250
300
350
0 50 100 150 200 250 300 350
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)
0
20
40
60
80
100
120
140
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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10
20
30
40
50
60
70
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)
0
5
10
15
20
25
30
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)
0
5
10
15
20
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