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

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Comparison with hourly

observations at Clinton site

P+M-XYLENES

00.5

11.5

22.5

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44.5

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O-XYLENE

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simulationComparison with

hourly observations at

Clinton site

124 TMB

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Comparison with hourly

observations at Clinton site

ETHYLBENZENE

00.20.40.60.8

11.21.41.61.8

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BENZENE

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(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

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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