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California Environmental Protection Agency. Air Resources Board. Regional Modeling Update. Ajith Kaduwela, Ph.D Luis F. Woodhouse, Ph.D. September 12, 2002. Collaborators. Emissions Paul Allen, P.E. Emissions Inventory Branch Meteorology Shuming Du, Ph.D. Kemal Gurer, Ph.D. - PowerPoint PPT Presentation
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Regional Modeling Update
September 12, 2002
Air Resources BoardCalifornia Environmental Protection Agency
Ajith Kaduwela, Ph.DLuis F. Woodhouse, Ph.D.
Collaborators• Emissions
– Paul Allen, P.E.– Emissions Inventory Branch
• Meteorology– Shuming Du, Ph.D.– Kemal Gurer, Ph.D.– Daniel Chau, Ph.D
• Air Quality– Luis Woodhouse, Ph.D.– Jinyou Liang, Ph.D.
• Chemistry– Bruce Jackson, M.S.
Outline• Summary of Draft Modeling Protocol
• Photochemical Models Used
• Model Input Preparation
• Meteorological Models Used
• Modeling Results/Performance Evaluation
• MATES-II, CRC/DOE/NERL Study
• Future Work
Summary of Modeling Protocol
• Modeling Approach:– Apply air quality models to assess health
impacts from direct inhalation at both micro and regional scale.
– Micro-scale modeling for near source impacts– Regional scale to simulate transport of
pollutants from all emission sources in Southern California
Modeling Protocol (cont.)
• Simulate air quality from January 1 to December 31, 1998
• Modeling Domain– 87 x 67 cells– 4 x 4 km2 grid size
Regional Modeling Domain
San Diego
Riverside
Los AngelesSan BernardinoVentura
Orange
Mexico
Modeling Protocol (cont.)
• Emissions– Seasonal weekend and weekday inventories
instead of monthly– Total of 8 emission inventories
• Chemical Mechanism– SAPRC-99– Modified to include additional toxics
Toxics– 1,3-butadiene– Formaldehyde– Acetaldehyde– Acrolein – Benzene– Carbon tetrachloride– Chloroform– Dichloromethane– 1,2-Dichloroethane– o-Dichlorobenzene– p-Dichlorobenzene– Ethylene oxide– Styrene– Toluene
– Trichloroethylene– Vinyl Chloride– Xylenes– Diesel PM10– Arsenic– Beryllium– Cadmium– Hexavalent Chromium– Iron– Lead– Manganese– Mercury– Nickel– Zinc
Modeling Protocol (cont.)
• Two grid-base photochemical models
– Run Models-3/CMAQ for selected episodes
– Run one air quality model for entire 1998• using CALGRID instead of UAM-FCM
Air Quality Model Change
• Why not UAM-FCM?– Based on older version of UAM (UAM-IV)– No longer supported– Chemical solver difficulties
• Why CALGRID?– Better formulation than UAM-IV– Better documentation– Flexible chemical mechanism
CALGRID
• Grid-based photochemical model developed in 1989 for ARB and last updated in 2000 (Version 1.6b)
• Choice of chemical mechanisms (CB4 or SAPRC)
• ARB’s implementation of a flexible chemical mechanism interface
Community Multiscale Air Quality Modeling System
Models-3/CMAQ
• Photochemical air quality model first released in 1999 with EPA funding.
• State-of-the-Science but limited use to date
• Continually under development
• Aqueous-phase chemistry, aerosol dynamics and modal size distributions, aerosol deposition, plume chemistry, and process analysis
CMAQ vs. CALGRID
• CMAQ– MM5– 17 vertical layers– Domain top: 14.6 km– SAPRC-99 with toxics– QSSA or SMVGEARSMVGEAR– dry deposition for some
toxic VOCs– first order decay for
deposition of PM– 7 days of CPU/month– 1 GB/day
• CALGRID– CALMET– 10 vertical layers– Domain top: 3 km– SAPRC-99 with toxics– QSSA or HybridHybrid– dry deposition for all
toxic VOCs– particulate deposition for
PM– 3 days of CPU/month– 0.5 GB/day
Model Input Preparation
• Initial and Boundary Conditions
• Emissions
• Meteorology
Initial and Boundary Conditions
• Initial and Boundary conditions same for each month– Boundary conditions same as for SCOS-97
• EPA Clean over ocean (40 ppb O3, 0.001 ppb NOx, and 20 ppbC VOC)
• South Coast clean over land (40 ppb O3, 2 ppb NOx, 60 ppbC VOC)
• MATES-II• 40 ppb O3, 1.5 ppb NOx, 30 ppbC VOC
Emissions
• Based on inventories developed for SCOS-97, adjusted to 1998
• Weekend and weekday inventories by season
• Using latest profiles, and surrogates to spatially allocate emissions
• Use latest version of EMFAC2000 for motor vehicle inventory with DTIM4
0
200
400
600
800
1,000
1,200
1,400
1,600
NOx VOC Toxics PM Biogenics
Winter WD Winter WE Summer WD Summer WE
Weekend and Weekday Area Source EmissionsWinter and Summer 1998
tons/day
0
10
20
30
40
50
60
NOx VOC Toxics PM toxics
Winter WD Winter WESummer WD Summer WE
Weekend and Weekday Elevated Emissions
tons/day
Levels
(kg/hr):
1 (B)
10 (G)
50 (Y)
80 (O)
100 (R)
Levels
(kg/hr):
1 (B)
10 (G)
50 (Y)
80 (O)
100 (R)
0 hr 6 hr
12 hr 16 hr
Summer Weekday
NO
Levels
(kg/hr);
1 (B)
2 (G)
3 (Y)
4 (O)
5 (R)
Levels
(kg/hr);
1 (B)
2 (G)
3 (Y)
4 (O)
5 (R)
0 hr 6 hr
12 hr 16 hr
Summer Weekday
BENZENE
Levels (kg/hr):
1 (B)
3 (G)
4 (Y)
5 (O)
6 (R)
Levels (kg/hr):
1 (B)
3 (G)
4 (Y)
5 (O)
6 (R)
0 hr 6 hr
12 hr 16 hr
Summer Weekday
DIESEL PM10
Meteorology
• Models require hourly meteorological data for each grid in domain
• Models needed to create gridded meteorological fields– Prognostic: predicts from first principles, mass
and energy transfer equations (MM5)– Diagnostic: uses observational data
(CALMET)
NCAR/Penn State Mesoscale Model (MM5)
• Advanced state-of-the-science prognostic regional model– solves conservation equations to predict winds
and temperatures– requires initial conditions, and boundary
conditions for each hour simulated
• Applied with one coarse and one nested domain
MM5 (cont.)
• Analysis nudging used but no Data assimilation (FDDA)
• 27 vertical layers (matched to 17 for air quality simulations)
• MM5 exercised for entire 1998
CALMET
• Diagnostic generation of meteorological fields with objective analysis
• Parameterized treatments of slope flows, kinematic terrain effects, terrain blocking effects, and a micro meteorological model for overland and overwater boundary layers
CALMET (cont.)
• Model driven by observations– 10 National Weather Service surface sites– ~100 California Irrigation Management System
(CIMIS) surface stations– One upper air (NWS) site and two buoys– ~60 surface ARB/District monitoring sites (for
January and August only)
Model Output Example:August 5, 1998 @ 12:00hrs
MM5 CALMET
Model Output Example:January 20, 1998 @ 12:00hrs
MM5 CALMET
Model Performance Evaluation
• Process of establishing that an air quality model is adequately reproducing the chemical and physical processes that generate and transport pollutants (“right answer for the right reason”)
• Spatial and temporal evaluations needed
Model Performance Evaluation
• Procedures well established for episodic hourly concentrations of O3
– peak estimation accuracy, mean bias, variance, gross error, scatter plots, time series plots, and isopleths
– diagnostic and sensitivity simulations
• No procedure established for 24-hr or annual concentrations
• Approach:– Hourly evaluation of selected episodes for O3,
NOx, and CO using ARB guidance
– Several days to monthly evaluation of O3, NOx, CO, toxic VOCs (24-hr) and PM components
– Annual performance evaluation
Model Performance Evaluation (cont.)
Data For Model Evaluation
• 1-hr average concentrations for all 1998• O3, NO, CO, NO2
• ARB and District monitoring sites
• 24-hr Average concentrations for PM10 components
• 24-hr measurements for selected VOCs
Completed Simulations• CMAQ/Models-3
– August 1- 7, 1998
– January 1-31, 1998
– Performance evaluation
• CALGRID– August 1-7, 1998
– January 1-31, 1998
– Performance Performance evaluationevaluation
Domain Peak 1-hr Ozone (ppb)August 2-7, 1998
Day Observed CALGRID CMAQ
Aug 2 188 173 285Aug 3 165 163 294Aug 4 170 205 279Aug 5 202 147 234Aug 6 197 178 220Aug 7 206 120 277
Peak O3
Aug 2 @ 14 hrs
CALGRID
CALGRID
CMAQ: AUG 2 @ 17 hrs CMAQ: AUG 3 at 16 hrs
Aug 3 @ 13 hrs
24-hr Model PerformanceAugust 1-7, 1998
• Calculated 24-hr monthly average for O3, CO, and NOx (from hourly values) and compare with predictions
• Insufficient data to fully assess 24-hr model performance for toxics
02468
1012141618202224
BU
TD
C6H
6
C7H
8
CC
HO
HC
HO
DIC
M
MT
BE
TC
E
AR
SE
IRO
N
LE
AD
MA
NG
NIC
K
ZIN
C EC
PM
10
CO
NO
NO
2
O3
CMAQ CALGRID
Ratio of Predicted-to-Observed 24-hr averages for Toxics on August 1-7, 1998
Observed Maximum 1-hr OzoneJanuary 1-31, 1998
Concentration(ppb)
Date
Observed 79 January 1
CMAQ 154 January 18
CALGRID 143 January 26
CMAQ/Models-3 January 18 @ 14 hrs
January 1998 Predicted Ozone Distribution During Peak
CALGRIDJanuary 26, 1998 at 16 hrs
24-hr Model PerformanceJanuary
• Calculated 24-hr monthly average for O3, CO, and NOx (from hourly values) and compare with predictions
• Insufficient data to fully assess 24-hr model performance for toxics
Ratio of Predicted-to-Observed 24-hr Averages for Toxics on January, 1998
0
2
4
6
8
10
12
14
16
BUT
D
C6H
6
C7H
8C
CH
O
DIC
M
HC
HO
MT
BE
OX
YL
PER
C
TCE
IRO
N
LEA
DM
AN
G
NIC
K
ZIN
C
PM10 CO NO
NO
2
O3
CMAQ CALGRID
SUMMARY
• Prepared inputs for all 1998 for CALGRID and CMAQ/Models-3
• Simulated an extended period (January) and part of August with CALGRID and CMAQ/Models-3
• 24-hr average concentrations: On average both models show similar 24-hr performance (both January and August 1-7)
MATES IIMultiple Air Toxics Exposure Study II
• South Coast Air Quality Management District
• Monitored ~30 pollutants from April 1, 1998 to March 31, 1999 at 10 sites
• Air quality modeling for entire MATES II period– UAM with CB-IV and UAM-tox with updated CB-IV
• CALMET for meteorology
• Domain– 105 x 60 cell (2x2 km2), 5 layers ; region top of 2 km
CRC & DOE/NREL Study
– Final report dated June 30, 2000– CAMx/RTRAC to treat reactive inert species– Simulated MATES II using CB-IV
• MATES II Mobile source emissions EMFAC7G
• MATES II Mobile source emissions update to reflect EMFAC2000
• Meteorological fields from CALMET
• 10 MATES-II sites for model performance
• August 3-7, 1997 (MM5, CB-IV and SAPRC-99)
Future Work
• January, 2003:– CALGRID for entire year– Models-3/CMAQ for selected periods – Model performance evaluation– Annual averages and potential risks– Contour plots of risk by species and total risk
• February, 2003: – Draft report
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