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Integration of Criteria and Integration of Criteria and
Toxic Pollutants in SMOKE Toxic Pollutants in SMOKE
Madeleine Strum, OAQPSCollaborators: Marc Houyoux, MCNC/EMC
Ron Ryan & Greg Stella, OAQPSBill Benjey & Gerald Gipson, ORD
Rich Cook, OTAQ
For the Models 3 User’s Workshop October 22, 2002
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EPA’s Toxics and Criteria EPA’s Toxics and Criteria Modeling Systems SeparateModeling Systems Separate
Photochemical vs GaussianPhotochemical vs Gaussian
SMOKE vs EMS-HAPSMOKE vs EMS-HAP
Criteria vs NTICriteria vs NTI
Issues:
Sound Science
Consistency
Efficiency
EPA is moving towards one-atmosphere modeling to address these issues
GridGrid
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One-Atmosphere Approach One-Atmosphere Approach
National Emissions Inventory
SMOKE
CMAQ
Modify to process multipollutant inventories
Add capabilities for toxics
Still two separate inventories for 1999: toxics (HAPs) & criteria
COMMENTS:
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Main Issue for SMOKE is to Main Issue for SMOKE is to Address Overlap in Pollutants Address Overlap in Pollutants
No double-countingNo double-counting Use of toxics inventory pollutants, where Use of toxics inventory pollutants, where
possiblepossible Conservation of VOC mass, where Conservation of VOC mass, where
possiblepossible
Note: even though we’re not looking at particulates, addressing the VOC – HAP overlap will impact PM modeling
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Steps in Determining Changes Steps in Determining Changes Needed to SMOKENeeded to SMOKE
Examine criteria and toxics inventories; Examine criteria and toxics inventories; select when to use toxics in cases of overlapselect when to use toxics in cases of overlap• Mobile sources: EPA-generated nonroad and Mobile sources: EPA-generated nonroad and
MOBILE6 onroad inventories for toxics and critera MOBILE6 onroad inventories for toxics and critera are consistentare consistent
• Stationary source: Generally not consistentStationary source: Generally not consistent Examine potential modeling applicationsExamine potential modeling applications
• Modeling ozone/PM using emission estimates for Modeling ozone/PM using emission estimates for toxics from the toxics inventory in place of the toxics from the toxics inventory in place of the criteria inventorycriteria inventory
• Modeling toxics using emission estimates for Modeling toxics using emission estimates for toxics from the toxics inventorytoxics from the toxics inventory
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Steps in Determining Changes Steps in Determining Changes Needed to SMOKE (continued)Needed to SMOKE (continued)
Determine how CMAQ could be modified for Determine how CMAQ could be modified for the applicationsthe applications• No modifications needed for modeling ozone/PMNo modifications needed for modeling ozone/PM• Develop new mechanisms and solvers to handle Develop new mechanisms and solvers to handle
toxicstoxics– Modify CB-IV to treat key toxics explicitly (e.g., Modify CB-IV to treat key toxics explicitly (e.g.,
formaldehyde and acetaldyde)formaldehyde and acetaldyde)– Add capability to approximate chemical loss of other Add capability to approximate chemical loss of other
toxics outside chemical mechanism via pseudo-first toxics outside chemical mechanism via pseudo-first order reaction ratesorder reaction rates
Determine model species needed and how Determine model species needed and how SMOKE will produce them – see next slide for SMOKE will produce them – see next slide for details details
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For Ozone/PM Modeling
Mobile sources: integration - toxic pollutants (gaseous organic HAP) from toxics inventory - non toxics (nonHAP VOC) from criteria inventoryStationary sources: speciate criteria
How SMOKE Will Produce Model How SMOKE Will Produce Model SpeciesSpecies
For Toxics ModelingMobile sources: integration (same as above)Stationary sources: - speciate criteria for mechanism species that are not toxics - use toxics inventory for mechanism species that are explicit toxics (e.g., formaldehyde) - use toxics inventory for toxics modeled outside of mechanism
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VOC or TOG (criteria) emissions
Gaseous HAP emissions
Create NONHAPTOG or NONHAPVOC:
= VOC – sum(gaseous toxics species)
Speciation
Model species
New SMOKE function
Existing SMOKE function: but new speciation profiles are needed
Integration Approach for Mobile Integration Approach for Mobile SourcesSources
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Practical Considerations for Practical Considerations for IntegrationIntegration
The emission sources must be exactly the same The emission sources must be exactly the same for the toxics and the VOC/TOG for the toxics and the VOC/TOG
The methodology to estimate emissions should The methodology to estimate emissions should be consistent between the two inventoriesbe consistent between the two inventories
Both of these hold true for EPA-generated nonroad emissions and MOBILE6 generated emissions
Generally, these don’t hold true for stationary sources
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Integration for Onroad Mobile SourcesIntegration for Onroad Mobile Sources
SMOKE runs MOBILE6.2 to generate TOG and 26 gaseous SMOKE runs MOBILE6.2 to generate TOG and 26 gaseous HAPs such as benzene, acetaldehdye, PAHsHAPs such as benzene, acetaldehdye, PAHs
For each emission source, SMOKE creates a nonHAPTOG For each emission source, SMOKE creates a nonHAPTOG pollutant by subtracting the toxics from the TOGpollutant by subtracting the toxics from the TOG
SMOKE applies speciation profiles for nonHAPTOG and SMOKE applies speciation profiles for nonHAPTOG and individual HAPs to generate emissions of model species.individual HAPs to generate emissions of model species.
For a toxic modeled outside the mechanism, SMOKE maps For a toxic modeled outside the mechanism, SMOKE maps the toxic to itself and its mechanism speciesthe toxic to itself and its mechanism species
EXAMPLE SPECIATION PROFILES FOR ONROAD SOURCES1313A NONHAPTOG OLE 0.00127373705 1 0.03570111313A NONHAPTOG PAR 0.03439269933 1 0.4911160000 BENZENE BENZENE 1.00 78.11 1.00000 BENZENE PAR 1.00 78.11 0.16666670000 BENZENE NR 5.00 78.11 0.8333333
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Integration for Nonroad Mobile Integration for Nonroad Mobile SourcesSources
Similar to OnroadSimilar to Onroad
SMOKE imports toxic and criteria nonroad SMOKE imports toxic and criteria nonroad emission sources to be integrated- user emission sources to be integrated- user assures consistency in sourcesassures consistency in sources
SMOKE creates a nonHAPVOC pollutant SMOKE creates a nonHAPVOC pollutant by subtractionby subtraction
SMOKE applies speciation profilesSMOKE applies speciation profiles
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Approach For Stationary Sources is Approach For Stationary Sources is Replacement, not IntegrationReplacement, not Integration
SMOKE imports both criteria and toxic inventories SMOKE imports both criteria and toxic inventories SMOKE speciates criteria inventory using speciation profiles SMOKE speciates criteria inventory using speciation profiles
that zero out the explicit toxics model species (e.g., that zero out the explicit toxics model species (e.g., formaldehyde) formaldehyde)
SMOKE maps the toxics inventory pollutants to the CB-IV SMOKE maps the toxics inventory pollutants to the CB-IV explicit toxics model speciesexplicit toxics model species
For a toxic modeled outside the mechanism, SMOKE maps For a toxic modeled outside the mechanism, SMOKE maps the toxic to itself, but not its mechanism speciesthe toxic to itself, but not its mechanism species
EXAMPLE SPECIATION PROFILES FOR STATIONARY SOURCES0307 TOG OLE 0.00126649899 1 0.035530307 TOG PAR 0.03791738749 1 0.53972670000 FORM FORM 0.00126649899 1 0.035530000 BENZENE_ST BENZENE 1.00 30.03 1
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SummarySummary We have explored one-atmosphere modeling We have explored one-atmosphere modeling
using toxics and criteria inventories in the using toxics and criteria inventories in the SMOKE/CMAQ modeling system, focusing on SMOKE/CMAQ modeling system, focusing on gaseous HAPSgaseous HAPS
Benefits to ozone/PM modeling: better Benefits to ozone/PM modeling: better estimates of a subset of the pollutants (gaseous estimates of a subset of the pollutants (gaseous TOG) than current VOC speciation approachTOG) than current VOC speciation approach
Benefits to Toxics modeling: allows for use of Benefits to Toxics modeling: allows for use of photochemical grid models with toxics inventoryphotochemical grid models with toxics inventory
Wider integration will be possible when Wider integration will be possible when inventories become more consistentinventories become more consistent
