Estimation of Paved and UnpavedEstimation of Paved and UnpavedRoad Dust Emissions in MexicoRoad Dust Emissions in MexicoMarty Wolf and Paula FieldsMarty Wolf and Paula FieldsERG, Inc.ERG, Inc.Sacramento, CASacramento, CASalvador GonzálezSalvador González-AyalaInternational Communities Research CenterInternational Communities Research CenterEl Paso, TXEl Paso, TXNARSTO Emissions Inventory WorkshopNARSTO Emissions Inventory WorkshopAustin, TexasAustin, TexasOctober 14October 14-17, 200317, 20032Mexico National EmissionsMexico National EmissionsInventoryInventory-CharacteristicsCharacteristics•Multi-year developmentyear development•1999 criteria pollutant base year inventory1999 criteria pollutant base year inventoryfor entire country at municipality levelfor entire country at municipality level•Multi-phase releasephase release–Draft inventoryDraft inventory-released July 2003released July 2003–Draft final inventoryDraft final inventory-expected Spring 2004expected Spring 2004–Final inventoryFinal inventory-expected Summer 2004expected Summer 20043On-Road Mobile SourcesRoad Mobile Sourcesin Mexicoin Mexico•Mexico populationMexico population-97 million97 million•Vehicle populationVehicle population-18 million18 million•VKT estimates needed for entire country atVKT estimates needed for entire country atmunicipalitymunicipality-level, but limited datalevel, but limited dataavailabilityavailability•No existing estimates for VKT splitNo existing estimates for VKT splitbetween paved and unpaved roadsbetween paved and unpaved roads4Methodology StepsMethodology Steps•Traffic volume and congestion modeling forTraffic volume and congestion modeling forrepresentative urban areasrepresentative urban areas•Determine daily per capita VKT for eachDetermine daily per capita VKT for eachrepresentative urban arearepresentative urban area•Link-specific traffic volumes combinedspecific traffic volumes combinedwith paved/unpaved road data to determinewith paved/unpaved road data to determinepaved and unpaved VKT splitpaved and unpaved VKT split5Representative Urban AreasRepresentative Urban AreasCity/Town Class Population RangeRepresentativeUrban AreaSmall Town <25,000 Castaños, CoahuilaMedium Town 25,000 – 100,000 Río Bravo, TamaulipasLarge Town 100,000 – 250,000 Ensenada, Baja CaliforniaSmall City 250,000 – 1,000,000 Hermosillo, SonoraMedium City 1,000,000 – 2,000,000 Ciudad Juárez, ChihuahuaLarge City 2,000,000+ Monterrey, Nuevo LeónMexico City Mexico City6Traffic Volume andTraffic Volume andCongestion ModelingCongestion Modeling•Ciudad Juárez disaggregated trip generation ratesCiudad Juárez disaggregated trip generation rates•Zone-level structure developed for each arealevel structure developed for each area•Zone-level trip generations estimated usinglevel trip generations estimated usingstatisticsstatistics•Trip productions and trip attractions balancedTrip productions and trip attractions balanced•Roadway network developed to distribute tripsRoadway network developed to distribute trips•Links assigned function class, flow direction, linkLinks assigned function class, flow direction, linkcapacity, and average daily speedcapacity, and average daily speed7Zone-Level StructureLevel Structure-HermosilloHermosillo8Primary Roadway NetworkPrimary Roadway Network-HermosilloHermosillo9Traffic Volume and CongestionTraffic Volume and CongestionModelingModeling-Cont.•Transportation engineering gravity modelTransportation engineering gravity modelappliedapplied•Person-trips converted to vehicletrips converted to vehicle-trips•Iterative solution for gravity modelIterative solution for gravity model•Generate linkGenerate link-level loaded networklevel loaded network10Loaded NetworkLoaded Network-HermosilloHermosillo11Estimation of Per Capita VKTEstimation of Per Capita VKT•VKTlink= Volume= Volumelink× Length× Lengthlink•VKTTotal=Σ(VKTlink)•Per Capita VKT = VKTPer Capita VKT = VKTTotal/Population/Population12Per Capita VKTPer Capita VKTRepresentative Urban Area Daily Per Capita VKTCastaños 1.9Río Bravo 1.6Ensenada 4.3Hermosillo 5.2Ciudad Juárez 6.2Monterrey 9.4Mexico City 6.313Methodology for EstimatingMethodology for EstimatingPaved/Unpaved Road VKT SplitPaved/Unpaved Road VKT Split•Link level VKT estimated for representativeLink level VKT estimated for representativeurban areasurban areas•Paved/unpaved road information obtainedPaved/unpaved road information obtainedfor each representative urban areafor each representative urban area•Link level VKT and paved/unpaved roadLink level VKT and paved/unpaved roadinformation overlaid to determineinformation overlaid to determinepaved/unpaved road VKT splitpaved/unpaved road VKT split14Paved/Unpaved RoadPaved/Unpaved RoadInformationInformation•Existing GISExisting GIS-Ciudad JuárezCiudad Juárez•Field MappingField Mapping-Castaños and Río BravoCastaños and Río Bravo•Satellite ImagesSatellite Images-Ensenada and HermosilloEnsenada and Hermosillo•Aerial PhotographsAerial Photographs-Monterrey and MexicoMonterrey and MexicoCity15Paved/Unpaved RoadsPaved/Unpaved Roads-HermosilloHermosillounpavedunpavedpavedpaved16Paved/Unpaved VKT SplitsPaved/Unpaved VKT SplitsRepresentativeUrban AreaPaved/UnpavedSurface Area SplitPaved/UnpavedVKT SplitCastaños 0.16/0.84 0.74/0.26Río Bravo 0.46/0.54 0.83/0.17Ensenada 0.50/0.50 0.92/0.08Hermosillo 0.65/0.35 0.97/0.03Ciudad Juárez 0.49/0.51 0.95/0.05Monterrey pending pendingMexico City pending pending17Mexico VKT EstimatesMexico VKT Estimates•Total VKT = 155.0 billion VKT/yearTotal VKT = 155.0 billion VKT/year•Paved Road VKT = 144.4 billion VKT/yearPaved Road VKT = 144.4 billion VKT/year(93.1%)(93.1%)•Unpaved Road VKT = 10.7 billionUnpaved Road VKT = 10.7 billionVKT/year (6.9%)VKT/year (6.9%)18Emission FactorsEmission Factors•Estimated using APEstimated using AP-42 emission factor42 emission factorequations (Sections 13.2.1 and 13.2.2)equations (Sections 13.2.1 and 13.2.2)•Silt loading, vehicle weight, silt content,Silt loading, vehicle weight, silt content,soil moisturesoil moisture-currently using values fromcurrently using values fromCiudad JuárezCiudad Juárez•Working to incorporate the effects ofWorking to incorporate the effects ofprecipitation and transport fractionprecipitation and transport fraction19Comparison of Paved andComparison of Paved andUnpaved Road Dust EmissionsUnpaved Road Dust EmissionsInventory Area PM10(Mg/yr)PM2.5(Mg/yr)U.S. Border Paved 389,303 97,326Mexico Border Paved 100,581 24,052U.S. Border Unpaved 2,183,916 327,588Mexico Border Unpaved 469,935 68,68320SummarySummary•Methodology useful for areas with limited vehicleMethodology useful for areas with limited vehicleactivity dataactivity data•Emissions can be developed for a large number ofEmissions can be developed for a large number ofmunicipalities, while focusing data collection onmunicipalities, while focusing data collection onsmall number of representative areassmall number of representative areas•Different types of paved/unpaved roadDifferent types of paved/unpaved roadinformation can be usedinformation can be used•Emission estimates can be improved with moreEmission estimates can be improved with morelocationlocation-specific dataspecific data