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Recent Developments in Air Quality Modeling Techniques for studying Air Toxics in the Houston-Galveston Area
Prof. Daewon W. ByunDr. Soontae Kim, Ms. Violeta Coarfa
Dr. Peter PercellUniversity of Houston
Institute for Multidimensional Air Quality Studies
Dr Graciela Lubertino,Houston Galveston Area Council
Jason Ching,U.S. EPA
Workshop for Air Toxics and Health Effects
October 17-18, 2005 University of Houston
http://www.imaqs.uh.edu
Why modeling air toxics?Why modeling air toxics? To better understand their impacts on human To better understand their impacts on human
health and air qualityhealth and air quality To protect public health by limiting their emissions To protect public health by limiting their emissions
from man-made sourcesfrom man-made sources To help communities prepare to better respond in To help communities prepare to better respond in
case of chemical spills of such substancescase of chemical spills of such substances
Air toxics assessment activities includeAir toxics assessment activities include- assessment of emissions: monitoring and modeling - assessment of emissions: monitoring and modeling
of air qualityof air quality- programs for reducing exposure and emissions of - programs for reducing exposure and emissions of
pollutants;pollutants;- development and implementation of control - development and implementation of control
strategies of emissions; strategies of emissions; - emergency response in case of serious events.- emergency response in case of serious events.
Fate-Transport ModelingBased on First Principles”
Linking Air Quality and Exposure Modeling
Estimate emissions
Obtain concentrations of chemical in the medium
at distance of interest
Determine exposure of the population
of interest
Calculate the risk ofinjury associated with
that exposure
Ching, 2005 presentation
For neighborhood scale modeling:
Method 1: Combine CMAQ with ASPEN (following EPA’s Philadelphia Study)
Method 2: Apply trajectory adaptive grid (TAG) method
Air toxics modeling Follows Ozone & PM approach
Where we are now….
What we need to work on…
Ching, 2005 presentation
Meteorology
Air Quality
US Continent
Regional/State
HG area
Neighborhood scale
HAPEM
Key Issue: How to improve Key Issue: How to improve Air Toxics Emissions Air Toxics Emissions
InventoriesInventories Air toxics Emissions Processing MethodAir toxics Emissions Processing Method Separate processing: of toxics species that Separate processing: of toxics species that
do not get involved in the main chemistry do not get involved in the main chemistry (i.e. CMAQ/HAPS)(i.e. CMAQ/HAPS)
Combined processing of toxics with other Combined processing of toxics with other photochemical (O3) and PM model species photochemical (O3) and PM model species with full interaction (i.e. extended SAPRC) with full interaction (i.e. extended SAPRC) CMAQ/Air-ToxicsCMAQ/Air-Toxics
Which Emissions Inventory?Which Emissions Inventory? Which Model Species?Which Model Species? How to process??How to process??
http://www.imaqs.uh.edu
Toxic Emissions InventoriesToxic Emissions Inventories
NEI Criteria VOC emissions NEI Criteria VOC emissions Needs proper speciation profilesNeeds proper speciation profiles
NEI HAP emissionsNEI HAP emissions One-to-one mappingOne-to-one mapping
Texas Criteria VOC emissionsTexas Criteria VOC emissions Needs proper speciation profilesNeeds proper speciation profiles
Texas PSDBTexas PSDB Speciated: One-to-one mappingSpeciated: One-to-one mapping
MOBILE6.2 Toxic emissions from HGACMOBILE6.2 Toxic emissions from HGACAdditional Efforts Required
EPA air toxicsInventories available
What we did
What we are working on now
Preliminary CMAQ/AT Preliminary CMAQ/AT ResultsResults
Preliminary studies have been done using three Preliminary studies have been done using three different inventoriesdifferent inventories
Emissions DataEmissions Data 1. EPA’s National Emissions Inventory 1. EPA’s National Emissions Inventory NEI99NEI99 : : Criteria (Criteria (CAPs)CAPs) + Hazardous ( + Hazardous (HAPs)HAPs) Tools: SMOKE ; CMAQ/Air-Toxics ; PAVETools: SMOKE ; CMAQ/Air-Toxics ; PAVE Domain: 4km_83x65Domain: 4km_83x65 Period: Aug, 22 – Aug, 31, 2000Period: Aug, 22 – Aug, 31, 2000
Simulation results were compared with the Simulation results were compared with the observationsobservations
Emissions for toluene and ethylbenzeneEmissions for toluene and ethylbenzene
Air Toxics Emissions
August 25, 200018:00 CDT
Point Area Non-road On-road
All Sources All Sources
Point Area Non-road On-road
NEI99 withNEI99 withSMOKE2.1SMOKE2.1ResultResult
CMAQ/AT 4.4 results for aromaticsCMAQ/AT 4.4 results for aromatics
August 25, 2000 @ 1 pm GMT and 9 pm GMT Air Concentrations
August 25, 200016:00 CDT
August 25, 200008:00 CDT
TOLUENE
0
5
10
15
20
con
c (p
pb
V)
observational Clinton
simulation
O-XYLENE
0
0.2
0.4
0.6
0.8
1
1.2
1.4
con
c (p
pb
V)
observational Clinton
simulation
Comparison with hourly
observations at Clinton site
P+M-XYLENES
00.5
11.5
22.5
33.5
44.5
8/22
8/23
8/24
8/25
8/26
8/27
8/28
8/29
8/30
8/31
con
c (p
pb
V)
simulation
observational Clinton
O-XYLENE
0
0.2
0.4
0.6
0.8
1
1.2
1.4
8/22
8/23
8/24
8/25
8/26
8/27
8/28
8/29
8/30
8/31
con
c (p
pb
V)
observational Clinton
simulationComparison with
hourly observations at
Clinton site
124 TMB
0
0.2
0.4
0.6
0.8
1
1.2
1.4
8/218/
228/
238/
248/
258/
268/
278/
288/
298/
308/
31
con
c (p
pb
V)
simulation
observational Clinton
135 TMB
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
8/21
8/22
8/23
8/24
8/25
8/26
8/27
8/28
8/29
8/30
8/31
con
c (p
pb
V)
observational Clinton
simulation
Comparison with hourly
observations at Clinton site
ETHYLBENZENE
00.20.40.60.8
11.21.41.61.8
8/218/
228/
238/
248/
258/
268/
278/
288/
298/
308/
31
con
c (p
pb
V)
observational Clinton
simulation
BENZENE
0
0.5
1
1.5
2
2.5
3
3.5
4
0822
0827
0828
0830
day
co
nc
(pp
bV
)
NEI99
NEI99+TRI00
TEIb4a+NEI99
Clinton site
TEIb4a+NEI99 gives a better agreement between the TEIb4a+NEI99 gives a better agreement between the simulation results and Clinton observational data for simulation results and Clinton observational data for benzenebenzene
Some success & some failures:But modeling advances are very promising if and only if we can improve emissions inventories…
2. 2. TEI00TEI00 + + NEI99NEI99: : TEIb4aTEIb4a + + HAPsHAPs3.3. NEI99NEI99 + + TRI00TRI00: : CAPsCAPs + ( + ( HAPsHAPs + +
TRI00TRI00))
Comparison with observations at
Clinton site
MOBILE 6.2 emissionsMOBILE 6.2 emissions
Estimation
NEI MOBILE MOBILE6
County-based Link-based
Spatial allocation Use surrogates Defined by location
Temporal allocationUse x-ref & profiles Hourly emissions
Species HAPs MSATs
Example species: BENZ, MTBE, BUTA, FORM, ACETA, ACROL, NAPTHALENE, ETHYLBENZE, N-HEXENE, STYRENE, TOLUENE, XYLENE, LEAD
What we are working on now Link-based
MSATS = mobile source air toxics species
How mobile emissions are How mobile emissions are estimated?estimated?
VMT factors,Capacity factors,
Speed model parameters
TransportationNetwork Data Set
TRANSVMT
Mobile6 input POLFAC RATEADJ
IMPSUM
VMT mix
Hourly emissions
MOBILE6: Input/OuputMOBILE6: Input/Ouput
Registration distribution- Registration distribution- TTITTI
Gasoline content – TCEQGasoline content – TCEQ Control programs – TCEQControl programs – TCEQ Trip data – H-GAC Trip data – H-GAC Temperature, humidity – SIPTemperature, humidity – SIP Diesel sales fractions – TTIDiesel sales fractions – TTI Calendar yearCalendar year
Emission factors Emission factors (g/mile) for different (g/mile) for different air chemical speciesair chemical species
INPUT OUTPUT
Mobile Source Air Toxics (MSAT) Mobile Source Air Toxics (MSAT) CompoundsCompounds
By default: Benzene, 1,3-Butadiene, By default: Benzene, 1,3-Butadiene, Formaldehyde, Acetaldehyde, Acrolein, MTBEFormaldehyde, Acetaldehyde, Acrolein, MTBE
Extended: Extended: Arsenic compounds, Chromium compounds, Arsenic compounds, Chromium compounds, Dioxin/Furans, Ethylbenzene, n-Hexane, Lead Dioxin/Furans, Ethylbenzene, n-Hexane, Lead
compounds,compounds,Manganese compounds, Mercury compounds, Manganese compounds, Mercury compounds,
Naphthalene,Naphthalene,Nickel compounds, Polycyclic Organic Matter, Styrene,Nickel compounds, Polycyclic Organic Matter, Styrene,Toluene, Xylene, Diesel, Particulate MatterToluene, Xylene, Diesel, Particulate Matter
Additional Parameters needed for Additional Parameters needed for Air Toxic CalculationsAir Toxic Calculations
GAS AROMATIC%: GAS AROMATIC%: aromatic content of gasoline on a aromatic content of gasoline on a percentage of total volume basispercentage of total volume basis
GAS OLEFIN%: GAS OLEFIN%: olefin content of gasoline on a percentage of olefin content of gasoline on a percentage of total volume basistotal volume basis
GAS BENZENE%: GAS BENZENE%: benzene content of gasoline on a benzene content of gasoline on a percentage of total volume basispercentage of total volume basis
E200: E200: Percentage of vapor a given gasoline produces at 200°FPercentage of vapor a given gasoline produces at 200°F E300: E300: percentage of vapor a given gasoline produces at 300°Fpercentage of vapor a given gasoline produces at 300°F OXYGENATE: OXYGENATE: oxygenate type and content of gasoline on a oxygenate type and content of gasoline on a
percentage of total volume basis. There are four oxygenate percentage of total volume basis. There are four oxygenate types in the model: MTBE, ETBE, ETOH, TAMEtypes in the model: MTBE, ETBE, ETOH, TAME
Houston Road Houston Road NetworkNetwork
What are required to estimatemobile source air toxics emissions?
Road Network, Nodes & Road Network, Nodes & LinksLinks
Processing is not always Processing is not always easy easy
– the link data can be – the link data can be
messed upmessed up
Link Nodes inside HGB 8 Link Nodes inside HGB 8 CountiesCounties
Link Nodes inside Harris Link Nodes inside Harris CountyCounty
Example of MOBILE6 Example of MOBILE6 outputsoutputs
Example Output FileExample Output FileAnode Bnode Roadtype Pollutant EmissionType grams emissions by vehicle Anode Bnode Roadtype Pollutant EmissionType grams emissions by vehicle
typetype 1653 10893 8 BENZ COMPOSITE 1.1234693 1.3399E-1 1653 10893 8 BENZ COMPOSITE 1.1234693 1.3399E-1 1653 10893 8 BENZ EXH_RUNNING 2.8073E-1 3.7492E-2 1653 10893 8 BENZ EXH_RUNNING 2.8073E-1 3.7492E-2 1653 10893 8 BENZ START 7.1150E-1 8.3485E-2 1653 10893 8 BENZ START 7.1150E-1 8.3485E-2 1653 10893 8 BENZ HOT_SOAK 3.3991E-2 3.0365E-3 1653 10893 8 BENZ HOT_SOAK 3.3991E-2 3.0365E-3 1653 10893 8 BENZ REST_LOSS 8.5768E-2 8.8688E-3 1653 10893 8 BENZ REST_LOSS 8.5768E-2 8.8688E-3 1653 10893 8 BENZ RUN_LOSS 1.1484E-2 1.1099E-3 1653 10893 8 BENZ RUN_LOSS 1.1484E-2 1.1099E-3 1653 10893 8 MTBE COMPOSITE 3.4736070 3.6643E-1 1653 10893 8 MTBE COMPOSITE 3.4736070 3.6643E-1 1653 10893 8 MTBE EXH_RUNNING 1.3982E-1 2.0251E-2 1653 10893 8 MTBE EXH_RUNNING 1.3982E-1 2.0251E-2 1653 10893 8 MTBE START 4.3882E-1 5.9574E-2 1653 10893 8 MTBE START 4.3882E-1 5.9574E-2 1653 10893 8 MTBE HOT_SOAK 8.3029E-1 7.4172E-2 1653 10893 8 MTBE HOT_SOAK 8.3029E-1 7.4172E-2 1653 10893 8 MTBE REST_LOSS 1.9068174 1.9717E-1 1653 10893 8 MTBE REST_LOSS 1.9068174 1.9717E-1 1653 10893 8 MTBE RUN_LOSS 1.5786E-1 1.5257E-2 1653 10893 8 MTBE RUN_LOSS 1.5786E-1 1.5257E-2 1653 10893 8 BUTA COMPOSITE 1.5084E-1 1.7860E-2 1653 10893 8 BUTA COMPOSITE 1.5084E-1 1.7860E-2 1653 10893 8 BUTA EXH_RUNNING 4.1085E-2 5.1978E-3 1653 10893 8 BUTA EXH_RUNNING 4.1085E-2 5.1978E-3 1653 10893 8 BUTA START 1.0976E-1 1.2663E-2 1653 10893 8 BUTA START 1.0976E-1 1.2663E-2 1653 10893 8 FORM COMPOSITE 4.3185E-1 6.3634E-2 1653 10893 8 FORM COMPOSITE 4.3185E-1 6.3634E-2
Example of Link-based Example of Link-based EmissionsEmissions VOC emissions from Brazoria CountyVOC emissions from Brazoria County
Example of Link-based Example of Link-based EmissionsEmissions
BenzeneBenzene TolueneToluene
XyleneXylene StyreneStyrene
Example of Link-based Example of Link-based EmissionsEmissions
BenzeneBenzene
http://www.imaqs.uh.edu
Further Processing of Further Processing of air toxics emissions air toxics emissions
with SMOKE for with SMOKE for CMAQ/AT modelingCMAQ/AT modeling
Link-to-griddedemissions
Input data EI Processing for AQMs
Temporalprofiles
SMOKEAllocating each link emissions to the covering cells
Preparing MOBILE6 emission / vehicle types for temporal allocation
Link-based MOBILE6output
Hourly Hourly emissionsemissions
Gridded MOBILE6emissions
Diurnal temporal x-ref and profile
http://www.imaqs.uh.edu
Point Source VOC Emissions in
Houston-Galeston
Static Adaptive Fine-mesh Eulerian (SAFE) Grid
Point source emissions inventory Point source emissions inventory differencesdifferences
Benzene Butadiene0
1
2
3
4
5
NEI99 TCEQ
Em
iss
i on
s (
t on
s/ d
ay
)
Differences in Benzene Differences in Benzene Emissions Emissions
from Point Sourcesfrom Point SourcesTCEQ PSDB 2000 NEI99 HAP
Differences in 1,3-Butadiene Differences in 1,3-Butadiene emissions emissions
from Point Sourcesfrom Point SourcesTCEQ PSDB 2000 NEI99 HAP
Processing of EI for speciated Processing of EI for speciated air toxics modeling requires air toxics modeling requires
speciation profilespeciation profile
SAPRC99SAPRC99 0005 TOG ALK1 0005 TOG ALK1 0.00083139342 1 0.0250.00083139342 1 0.025 0005 TOG ALK2 0005 TOG ALK2 0.00030721966 1 0.0080.00030721966 1 0.008 0005 TOG ARO1 0005 TOG ARO1 0.00007297401 1 0.010.00007297401 1 0.01 0005 TOG CH4 0005 TOG CH4 0.05162094763 1 0.8280.05162094763 1 0.828 0005 TOG ETHENE0005 TOG ETHENE 0.00417112299 1 0.1170.00417112299 1 0.117 0005 TOG OLE1 0005 TOG OLE1 0.00007129278 1 0.0030.00007129278 1 0.003
SAPRC ExtendedSAPRC Extended 0005 TOG CH4 0005 TOG CH4 0.90174382925 17.4718304 0.90174382925 17.4718304 0.82800000.8280000 0005 TOG ALK1 0005 TOG ALK1 0.01452596486 17.4718304 0.01452596486 17.4718304 0.02500000.0250000 0005 TOG ALK2 0005 TOG ALK2 0.00536810188 17.47183040.00536810188 17.4718304 0.0080000 0.0080000 0005 TOG ETHE 0005 TOG ETHE 0.07286676019 17.47183040.07286676019 17.4718304 0.1170000 0.1170000 0005 TOG OLE1 0005 TOG OLE1 0.00124558562 17.47183040.00124558562 17.4718304 0.0030000 0.0030000 0005 TOG BENZ 0005 TOG BENZ 0.00424974738 17.4718304 0.00424974738 17.4718304 0.01900000.0190000
CMAQ/AT withExtended Aromatic Chemistry Mechanism
Current Developments in Air Toxics Current Developments in Air Toxics ModelingModeling
at IMAQS, University of Houstonat IMAQS, University of Houston An Extended Chemical Mechanism of the An Extended Chemical Mechanism of the
EPA’s CMAQ for Air Toxics StudiesEPA’s CMAQ for Air Toxics Studies ((PosterPoster) )
Problem of popular chemical mechanisms: many chemical species are lumped; cannot simulated the behavior of individual compounds important in the atmospheric chemical processes and/or with serious impact on the human health and surroundings;
Solution: find methods to implement species of interest in the chemical mechanisms employed by the photochemical models - SAPRC99/extended (SAPRC99/extended (CMAQ/ATCMAQ/AT))
Suitable for studying Suitable for studying acute health effectsacute health effects and and verifying verifying auto GC and canister measurementsauto GC and canister measurementshttp://www.imaqs.uh.edu
Current Developments in Air Toxics Current Developments in Air Toxics ModelingModeling
at IMAQS, University of Houstonat IMAQS, University of Houston A Transport Model for the Air Toxics StudiesA Transport Model for the Air Toxics Studies
((PosterPoster)) Long-term simulations (several months, yearly) are preferred to
better analyze and understand the physical and chemical behavior of toxic pollutants
Health effect studies need long-term simulations for a proper correlation between pollutant concentration and various health conditions; need a faster model than CMAQ/Air-Toxics;
IMAQS developed an engineering version of CMAQ/Air-Toxics, which can simulates seasonal and annual simulations (CMAQ/HAPS)
Suitable for studying chronic health effects of air toxics
New method for air quality modeling -- New method for air quality modeling -- under under developmentdevelopment An Eulerian-Lagrangian Hybrid Modeling Method, Trajectory An Eulerian-Lagrangian Hybrid Modeling Method, Trajectory
Adaptive Grid (TAG) underdevelopment (Adaptive Grid (TAG) underdevelopment (CMAQ/TAGCMAQ/TAG)) Can handle multiscale air quality issues at reasonable Can handle multiscale air quality issues at reasonable
computational cost with high accuracycomputational cost with high accuracyhttp://www.imaqs.uh.edu
Lagrangian packets to represent Lagrangian packets to represent movement of pollutants, but in movement of pollutants, but in
Eulerian adative gridEulerian adative grid
2-D3-D
Eulerian Grid
Lagrangian packets
Trajectory Adaptive Grid (TAG) Trajectory Adaptive Grid (TAG) AlgorithmAlgorithm
(very, very preliminary results as (very, very preliminary results as of today)of today)
Eulerian Grid
Testing of TAG – O3 (UTC 20:00 Testing of TAG – O3 (UTC 20:00 Aug 25)Aug 25)
PreliminaryO3 simulation results
Eulerian (CMAQ-PPM)
TAG-Result
Maximum
Minimum Closest
Packet Average