Regional Modeling Update and Issues
description
Transcript of Regional Modeling Update and Issues
Regional ModelingUpdate and Issues
May 6, 2003
Air Resources Board
California Environmental Protection Agency
Luis F. Woodhouse, Ph.D.
RegionalModeling
IntegratedResults
Risk Assessment
Mapping andVisualization
MicroscaleModeling
Emissions andMeteorology
Outline
• Review of last meeting
• Regional modeling update
• Model evaluation
• Comparison with previous studies
• Integrating microscale and regional modeling
• Future analysis
• Future statewide modeling considerations
3
Review of Last Meeting (September 12, 2002)
• Previous studies– UAM and CAMx with Carbon Bond IV
– Select toxics
– Small domain
• Present study– CALGRID and CMAQ with SAPRC99
– Over 30 toxics
– Large domain• Note: CAMx not used since it’s implementation mechanism
software is not publicly available
4
Toxics– 1,3-butadiene– Formaldehyde– Acetaldehyde– Acrolein – Benzene– Carbon tetrachloride– Chloroform– Dichloromethane– 1,2-Dichloroethane– o-Dichlorobenzene– p-Dichlorobenzene– Ethylene oxide– Styrene
– Toluene– Vinyl Chloride– Xylenes– Hexavalent Chromium
– Diesel PM10
– PM10 Arsenic
– PM10 Beryllium
– PM10 Cadmium
– PM10 Lead
– PM10 Manganese
– PM10 Mercury
– PM10 Nickel
– PM10 Zinc
5
Regional Modeling Domain
San Diego
Riverside
Los AngelesSan BernardinoVentura
Orange
Mexico
6
Regional Modeling Domain
93,264 km2
87 x 67 grids(4 km x 4 km)
Model Inputs • Emissions
– SCOS97 adjusted to 1998– seasonal inventories (weekday/weekend)– latest profiles, surrogates, and EMFAC2000
(with DTIM4)
• Meteorology– CALMET: diagnostic model using data from over
200 sites– MM5: prognostic model
• Boundary conditions– same for each month, based on SCOS97
7
Regional Modeling Update
• CALGRID– January 1 to December 31, 1998
• CMAQ– January, April, August and November 1998
8
Model Performance
• Verify model’s ability to reproduce measured concentrations– Ozone: Performance standards are well
established
– Toxics: No established performance standards
9
Model PerformanceConclusions
• Iterative process is needed to improve ozone performance
• In general, model predicted annual average toxics concentrations are comparable with observations for most species
• Results comparable with previous studies
10
Ozone Model Evaluation• Compared daily ratios of model-predicted to
measured maximum ozone concentrations– CALGRID closer to observations– CMAQ over predicts
11
0
0.5
1
1.5
2
2.5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Day of Month (August 1998)
Ratio
CMAQ CALGRID
Ozone Model Evaluation (cont.)• Calculated daily average gross errors:
– Measure model’s overall ability to reproduce observed hourly ozone at each site above a specified threshold concentration
– Iterative process
12
0
0.2
0.4
0.6
0.8
1
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Day of Month (August 1998)CMAQ CALGRID
Toxic VOCs Model Evaluation
• Annual average concentrations– In general, model predictions are
comparable with the measured annual concentrations for most toxics VOC species
– Some species are significantly under predicted by both models: carbon tetrachloride, chloroform, ethylene chloride, styrene
13
1998 Annual Average Concentration in Los Angeles
0
1
2
3
4
5
6
7
AC
ET
BU
TD
C6H
6
C7H
8
CC
HO
CC
L4
CH
LO
DIC
M
HC
HO
MEK
PDC
B
PER
C
STY
R
TED
C
VC
HL
ppb
CALGRID CMAQ Observed
Annual Averages of Toxic VOCs
14
1998 Annual Average Concentrations in Anaheim
0
1
2
34
5
6
7
AC
ET
BU
TD
C6H
6
C7H
8
CC
HO
CC
L4
CH
LO
DIC
M
HC
HO
MEK
PD
CB
PER
C
STY
R
TED
C
VC
HL
ppb
CALGRID CMAQ Observed
1998 Annual Average Concentration in Chula Vista
00.5
11.5
22.5
33.5
AC
ET
BU
TD
C6H
6
C7H
8
CC
HO
CC
L4
CH
LO
DIC
M
HC
HO
MEK
PD
CB
PER
C
STY
R
TED
C
VC
HL
ppb
CALGRID CMAQ Observed
15
Annual Averages of Toxic VOCs
Annual Averages ofInert Toxics
• Diesel PM10
– Model predictions are comparable to observed elemental carbon results
• Hexavalent Chromium– Model predictions are below detection limit
• PM10 components
– Performance depends on species
16
Annual Average of Inert Toxics
1998 Annual Concentrations at Los Angeles
0
50
100
150
200
ARSE CADM CRVI DIES LEAD MERC NICK ZINC
ng/m
3
CALGRID CMAQ Observed
*
* DIES in ug/m3 compared to elemental carbon 17
1998 Annual PM10 Concentrations at Anaheim
0
50
100
150
ARSE CADM CRVI DIES LEAD MERC NICK ZINC
ng/m
3
CALGRID CMAQ Observed
1998 Annual Concentration at Chula Vista
0
20
40
60
ARSE CADM CRVI DIES LEAD MERC NICK ZINC
ng/m
3
CALGRID CMAQ Observed
18
*
*
*
* DIES in ug/m3 compared to elemental carbon
Annual Average of Inert Toxics
19μg/m3
CALGRID (1998)
ppb
Diesel PM10 Benzene
Comparison withPrevious Studies
• MATES II– April 1998 to March 1999 field study– Models
• UAM and recently CAMx• Carbon Bond IV reaction mechanism
• Our results are comparable
20
0
0.5
1
1.5
2
2.5
ppb
CALGRID CMAQ MATESII (UAM) Observed
Comparison with MATES IIBenzene
21
Comparison with MATES II Diesel PM10 vs. Elemental Carbon
02468
101214
ug/m
3
CALGRID CMAQ MATESII (UAM) Observed
22
Comparison with MATES II Formaldehyde
01
234
56
ANAH
BLO
G
BUR
K
CEL
A
CH
VA
CO
MP
FON
T
HPR
K
LGBH
PIC
O
RIV
R
SIM
I
UPL
A
WIL
M
ppb
CALGRID CMAQ MATESII (UAM) Observed
23
Integrating Microscale and Regional Modeling Results
• Microscale modeling estimates near source impacts (meters)
• Regional modeling estimates impacts from sources in a large area (km)
• Issue– double-counting
24
25
Barrio Logan Modeling Results
ISCST3 CALINE CALGRID BARRIO CHULA EL -----------BARRIO LOGAN-------------- LOGAN VISTA CAJON
DIESEL PM10
26
ISCST3 CALINE CALGRID BARRIO CHULA EL -----------BARRIO LOGAN-------------- LOGAN VISTA CAJON
BENZENE
Barrio Logan Modeling Results (cont.)
27
ISCST3 CALINE CALGRID BARRIO CHULA EL ---------BARRIO LOGAN-------------- LOGAN VISTA CAJON
HEXAVALENT CHROMIUM
Barrio Logan Modeling Results (cont.)
NA
Sensitivity Simulations Double Counting*
• In Barrio Logan, local emissions contribute less than 1% of the annual average concentration of most toxic species.
• In Wilmington, local emissions contribute 15%-90% of the annual average concentrations– Benzene (47%)– Diesel exhaust (40%)– 1,3-butadiene (16%)
28* simulations for all 1998 were done in each case with CALGRID
Sensitivity SimulationsBarrio Logan
• Changing boundary conditions has very small impact on annual average toxic concentrations
• Choosing different averaging periods – 12-month average toxic concentrations can be
significantly different from 4-month average concentrations
– 4-month average cumulative risk is about 10% higher than the 12-month average cumulative risk
29
Future Analysis• Improve estimates of background toxic
concentrations – Omit all toxics emissions in a cell– Omit toxic emissions from selected categories in a cell– Evaluate procedures for estimating contributions of
secondary species
• Evaluate deposition effect
• Run CALGRID using MM5 winds
• Conduct spatial analysis
30
Future Statewide Modeling Considerations
• Air quality model selection– CALGRID, CMAQ, CAMx, other – Atmospheric reaction mechanism– Run time (e.g., CALGRID with SAPRC99
and 4 km x 4 km grids, at least 6 months)
• Period simulated– Every day in a year or selected episodes
31
Future Statewide Modeling Considerations (cont.)
• Input preparation– Emissions – Meteorology (CALMET, MM5)
• Other considerations– Baseline year– Multiple year simulation– Storage requirements
32