Wilmington Air Quality Study Modeling for Neighborhood Assessment Todd Sax Vlad Isakov September 12, 2002 California Air Resources Board

Neighborhood Assessment Program ObjectiveProgram Objective –“Develop source-receptor based, cumulative impact/risk assessment methodologies suitable for evaluating neighborhood-scale air pollution impacts and for comparing neighborhood exposures within a region” (NAP Work Plan) –Develop tools for evaluating local scale impacts and targeting risk reduction strategies September 12, 2002California Air Resources Board

Wilmington Identified by MATES-II as one of the most impacted areas of the Los Angeles regionIdentified by MATES-II as one of the most impacted areas of the Los Angeles region September 12, 2002(source: MATES-II, pg. ES-12) Located nearLocated near –Freeways –Refineries –Ports –Local Traffic –Manufacturing –Local Facilities Wilmington MATES-II Health Risk

Wilmington Study Domain September 12, 2002California Air Resources Board

Wilmington Air Quality Study Project ObjectivesProject Objectives –Improve assessment methodologies –Evaluate model results –Develop recommendations for policy development –Communicate results and risks to the public Project ComponentsProject Components –Emissions Inventory –Dispersion Modeling –Model Evaluation –Health Risk Assessment –Exposure Assessment September 12, 2002California Air Resources Board

Emissions Point Sources Industrial Metal platers Refineries Manufacturing Facilities Other sources: Cr6+, DPM Commercial Gas stations Dry cleaners Autobody shops Warehouses Industrial diesel Welding facilities On-Road Sources Link-based inventory Evaluate with vehicle counts Off-Road Sources Marine - Port, ARB Dockside - Port, ARB Railroads - ARB, Port Exposure Microscale Modeling ISCST3 AERMOD CALINE4 Regional Modeling CALGRID and/or CMAQ Health Risk Modeling Results Inhalation health risk calculation Multi-media health risk calculation Health risk assessment Model Evaluation Tracer Studies June 2003 Powerplant elevated release Toxics Monitoring Multiple sites, June 2003 Focus on diesel particulate Coordination with POLA Uncertainty Assessment Focus on diesel and Cr6+ Estimate range of pollutant concentrations possible using Monte Carlo techniques Wilmington Neighborhood Assessment - Conceptual Plan Inventory Analysis Focus on diesel and Cr6+ Examine by source and release point Estimate range of possible emissions using Monte Carlo techniques Compile by release location

Emissions Inventory Goal: comprehensive emissions inventoryGoal: comprehensive emissions inventory –Industrial and Commercial Facilities Comparing multiple inventory sources (Federal, State, Local) Comparing multiple inventory sources (Federal, State, Local) Conducting on-site surveys of large and small facilities Conducting on-site surveys of large and small facilities –On-Road Mobile Sources Building link-based inventory using SCAG light and heavy duty travel demand models Building link-based inventory using SCAG light and heavy duty travel demand models –Off-Road Mobile Sources Supplementing off-road inventories with facility-specific emissions identified by survey Supplementing off-road inventories with facility-specific emissions identified by survey Working with Ports of Los Angeles and Long Beach in inventory development for sources of diesel PM Working with Ports of Los Angeles and Long Beach in inventory development for sources of diesel PM Integrating spatially allocated off-road emissions from multiple sources Integrating spatially allocated off-road emissions from multiple sources September 12, 2002California Air Resources Board

Over 2500 businesses in modeling domainOver 2500 businesses in modeling domain 195 facilities in CEIDARS195 facilities in CEIDARS Multiple inventory databasesMultiple inventory databases 240 facilities surveyed, ~50% have emissions240 facilities surveyed, ~50% have emissions More surveys plannedMore surveys planned Emissions Inventory - Facilities

195 facilities in CEIDARS195 facilities in CEIDARS Corrected geo- locationsCorrected geo- locations Integration with existing HRAsIntegration with existing HRAs Improved release locations and parametersImproved release locations and parameters Sampled for data quality evaluationSampled for data quality evaluation Emissions Inventory - Facilities

Integrating inventory with GIS platformIntegrating inventory with GIS platform 1 km or 100m grid cells1 km or 100m grid cells Drill-in capability on selected sourcesDrill-in capability on selected sources Emissions Inventory - Facilities

Emissions Inventory - On-Road Sources Wilmington Road Links, SCAG Models

Air Quality Modeling GoalGoal –Develop and evaluate methodologies to estimate annual average concentrations of pollutants released from multiple sources on a neighborhood scale Micro-scale modelingMicro-scale modeling –Focus on air toxics with defined unit risk factors or reference exposure levels and particulate –ISCST3, AERMOD, CALINE Regional modelingRegional modeling –Focus on southern California –30 toxic pollutants –Photochemical models (e.g. CMAQ and/or CALGRID) September 12, 2002California Air Resources Board

Long Beach, Aug./Sept. Summer - night-timeSummer - daytime September 12, 2002California Air Resources Board Wilmington Wind Patterns Typical coastal wind patternsTypical coastal wind patterns Daytime southerly and westerly flowDaytime southerly and westerly flow

Model Evaluation - Overview September 12, 2002California Air Resources Board Assess accuracy of model resultsAssess accuracy of model results –Tracer studies Received new contract between ARB, CEC, UCR to conduct a tracer release from an elevated stack in Wilmington Received new contract between ARB, CEC, UCR to conduct a tracer release from an elevated stack in Wilmington Use existing tracer data to evaluate model performance and improve model algorithms Use existing tracer data to evaluate model performance and improve model algorithms –Supplemental monitoring Focus on diesel particulate, but there is currently no acceptable method for measurement Focus on diesel particulate, but there is currently no acceptable method for measurement –Uncertainty analysis Assess uncertainty for a subset of facilities in the modeling domain: Diesel PM (DPM) and Hexavalent Chromium (CrVI) emissions Assess uncertainty for a subset of facilities in the modeling domain: Diesel PM (DPM) and Hexavalent Chromium (CrVI) emissions

Model Evaluation - Tracer Study September 12, 2002California Air Resources Board Model performance evaluation - ensure model predictions are reliableModel performance evaluation - ensure model predictions are reliable –Develop database of tracer concentrations –Extend existing tracer database Wilmington - elevated release (stack)Wilmington - elevated release (stack) –Improve dispersion algorithm urban boundary layer conditions urban boundary layer conditions large vertical gradients in wind speed and turbulence are present large vertical gradients in wind speed and turbulence are present –Goal: improve model algorithms, incorporate into dispersion models (such as AERMOD) Site: not yet chosen. Date: June 2003.Site: not yet chosen. Date: June 2003.

TRACER EXPERIMENTS IN WILMINGTON

Tracer Study - Dispersion Example

Model Evaluation - Toxics Monitoring September 12, 2002California Air Resources Board Diesel PM is major inhalation risk in WilmingtonDiesel PM is major inhalation risk in Wilmington –No accepted methodology for measuring DPM –Elemental carbon as a surrogate does not work well in all cases –Major CMB studies provide conflicting results Likely Approach - CMB Analysis with Polycyclic Aromatic Hydrocarbon measurementLikely Approach - CMB Analysis with Polycyclic Aromatic Hydrocarbon measurement –Multiple sites over several weeks, June –Measure PM 2.5, OC/EC, SVOC PAH, elements –Evaluate differences between sites, between days, and correlation between pollutants –Looking for additional funding to expand study

Model Evaluation - Uncertainty Analysis Provide context to estimated pollutant concentrations - evaluate assumptionsProvide context to estimated pollutant concentrations - evaluate assumptions –Uncertainty sources: emissions, spatial allocation of emissions, model options and release parameters, conceptual uncertainty in model physics – Approach Focus on selected sources: CrVI and DPM Focus on selected sources: CrVI and DPM Evaluate range of possible emissions from each source through survey, databases, analysis of emission factors Evaluate range of possible emissions from each source through survey, databases, analysis of emission factors Determine specific conditions of each emission release Determine specific conditions of each emission release Estimate range of inter-annual variability in meteorology Estimate range of inter-annual variability in meteorology Assess range of acceptable model options and conduct sensitivity analysis Assess range of acceptable model options and conduct sensitivity analysis Use Monte Carlo statistical techniques to estimate confidence limits in modeling results Use Monte Carlo statistical techniques to estimate confidence limits in modeling results

Health Risk Assessment Evaluate inhalation health riskEvaluate inhalation health risk Investigate alternative assessment methodsInvestigate alternative assessment methods –Goal: Provide perspective to inhalation health risk –Some pollutants have important multipathway component Estimate differences in predicted health risks through evaluating multipathway contributions for selected pollutants Estimate differences in predicted health risks through evaluating multipathway contributions for selected pollutants –True inhalation exposure is a function of the amount of pollutant people breathe. People spend time in microenvironments People spend time in microenvironments Microenvironmental pollutant concentrations may be different than outdoor, ambient concentrations Microenvironmental pollutant concentrations may be different than outdoor, ambient concentrations May be possible to use existing data and models to compare ambient exposure to total exposure for selected pollutants May be possible to use existing data and models to compare ambient exposure to total exposure for selected pollutants September 12, 2002California Air Resources Board

Expected Conclusions September 12, 2002California Air Resources Board Answer relevant policy questionsAnswer relevant policy questions –Which inventory sources are most important? –Do commercial facilities impact cumulative risk? If so which ones? –Can on-road emissions be accurately allocated to individual streets? If not, what can be done? –Which models are most appropriate for neighborhood assessment? Do approaches vary by pollutant? –How should models be improved? –How reliable are modeling results? –What is the impact of exposure to ambient air pollution relative to estimated personal exposure?