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RAIMI A Practical Approach for Implementing Cumulative Type Assessments on a Localized Scale

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Title: RAIMI A Practical Approach for Implementing Cumulative Type Assessments on a Localized Scale


1
RAIMI - A Practical Approach for Implementing
Cumulative Type Assessments on a Localized Scale
  • U.S. EPA Region 6
  • Multimedia Planning and Permitting Division
  • Chicago 2002

2
1.0 INTRODUCTION AND OVERVIEW
  • 1.1 Introductions
  • U.S. EPA Region VI
  • U.S. EPA Region V
  • Participants

3
1.0 INTRODUCTION AND OVERVIEW
  • 1.2 Seminar Objectives and Methods
  • Transfer EPA Region 6 experience in localized
    assessment
  • Review details in performing the localized
    assessment for Port Neches, Texas
  • Provide for participant interface on
    defining project objectives, resources, and
    constraints of a localized assessment

4
1.0 INTRODUCTION AND OVERVIEW
  • 1.3 Content and Materials
  • Stepwise methods with RAIMI case study example
  • Notebook of presentations and handouts by
    presenters
  • Demonstrations
  • Group discussions

5
2.0 COMMUNITY LEVEL ASSESSMENTS REGIONAL
PERSPECTIVE
  • Why Are Cumulative Type Risk-based Assessments
    Becoming So Popular
  • Reality - permitting/enforcement actions need to
    consider bigger picture as opposed to source by
    source permitting
  • we blindly focus on RCRA-regulated units, often
    in a forest of others are we making a
    difference with our resources?
  • Internal Agency Pressures challenged to find
    mechanisms that support cross program cooperation
    and sharing of resources

6
2.0 COMMUNITY LEVEL ASSESSMENTS REGIONAL
PERSPECTIVE
  • Why Are Cumulative Type Risk-based Assessments
    Becoming So Popular (cont.)
  • Public Simply Wants to Know Am I safe
    breathing/eating/drinking where me and my family
    live?
  • Regulatory and National Program Pressures
    challenged to develop localized assessment
    capabilities (e.g., Urban Air Toxics Strategy)
  • Simply a logical approach to a complex and
    often overwhelming issue

7
2.0 COMMUNITY LEVEL ASSESSMENTS - REGIONAL
PERSPECTIVE
  • Significant Intermingling of Industry and
    Neighborhoods
  • National Scale Studies Continue to Flag Problems
    in Several Region 6 States
  • Scale of Issues Too Large to Ignore
  • Holistic Answer Needed to Bottom-Line Questions
  • Multi-program/Cross Media
  • Receptor-based Approach

8
3.0 REGION 6'S APPROACH FOR DEVELOPING
CAPABILITIES TO DO LOCALIZED ASSESSMENTS
  • Conducted detailed review of national scale
    studies (NATA, CEP, Air Toxics Strategy, etc.)
  • Established practical implementation objectives
    conduct assessments that provide usable results
    that help us as regulators do our job (that
    includes being in a position to effectively, and
    with complete competence, work with industry,
    public, and other stakeholders)

9
3.0 REGION 6'S APPROACH FOR DEVELOPING
CAPABILITIES TO DO LOCALIZED ASSESSMENTS
  • Test technical approach through pilot studies of
    actual areas within region
  • Make real-time improvements to approach and tools
    based on what is learned from pilots
  • Develop risk management plan and communication
    strategy to facilitate use of results

10
4.0 RAIMI - Regional Air Impact Modeling
Initiative
  • Risk-based Prioritization Tool and Platform to
    Develop Multi-media Solutions to Environmental
    Problems

11
4.0 REGIONAL AIR IMPACT MODELING INITIATIVE
(RAIMI)
  • EPA Region 6 initiated design of the RAIMI
    Program in 1999 to evaluate
  • Region-wide estimation of potential health risks,
    on a community level of resolution, as a result
    of exposure to multiple contaminants/sources/expos
    ure pathways.
  • As a test of the RAIMI methods and approach, a
    Pilot Study was designed and implemented in a
    small area in southeast Texas.

12
4.0 REGIONAL AIR IMPACT MODELING INITIATIVE
(RAIMI)
  • Establishment of the RAIMI Program is being
    driven in part by national initiatives that
    identify the need for a more refined assessment,
    including
  • CUMULATIVE EXPOSURE PROJECT
  • RESIDUAL RISK REPORT TO CONGRESS
  • INTEGRATED URBAN AIR TOXICS STRATEGY
  • NATIONAL AIR TOXICS ASSESSMENT

13
  • CEP FINDINGS
  • HAPs Are Broadly Distributed
  • In Specific Locations, Concentrations May Result
    In Unacceptable Risk, Sometimes By An Order Of
    Magnitude Or More

CEP OBJECTIVES Estimate Exposure Levles For A
Wide Variety Of Toxic Pollutants Characterize The
National Distribution Of These Estimated Exposure
Levels Across Communities And Demographic
Groups Identify The Types Of Communities And
Demographic Groups Which Appear To Have The
Highest Exposure Levels Identify Potentially
Important (Based On Risk) Emissions Sources And
Pollutants For Which Information Is Most
Uncertain
14
RESIDUAL RISK REPORT TO CONGRESS - AS REQIRED BY
SECTION 112(f) OF THE CAA
The Residual Report To Congress Identifies Two
Objectives For Residual Risk Activities
Assess Any Risk Remaining After MACT Standard
Compliance
Set Additional Standards, If Necessary, To
Provide An Ample Margin Of Safety To Be Protective
Follows Benzene NESHAP In That Standards Are To
Be 10-4 For Max Individual And 10-6 For
Population (How Defined ??)
15
INTEGRATED URBAN AIR TOXICS STRATEGY AS REQUIRED
BY SECTION 112(k) OF THE CAA
The Strategy Consists Of Four Main Components
Source-specific And Sector-specific Standards
(Regulations)
National, Regional, And Community-based
Initiatives To Focus On Multi-media And
Cumulative Risk, Including Pilot Studies
NATA To Develop Analytical Tools (Models) And
Support Activities (Monitoring) To Identify
Risks, Track Progress Toward Risk Goals, And
Prioritize Efforts To Address Emissions And Risks
From Air Toxics

Educational And Outreach Activities To Reduce
Toxics Emissions
16
NATIONAL-SCALE AIR TOXICS ASSESSMENT
The Goal Is To Identify Those Air Toxics Which
Are Of Greatest Potential Concern, In Terms Of
Contribution To Population Risk
National Scale Study That Includes 33 Air Toxics
17
4.0 RAIMI COMPLEMENTS NATIONAL INITIATIVES
  • Complements national scale studies by providing
    neighborhood-level assessment of potential risk
  • Is a means to rapidly assess source category
    specific risk before and after the
    implementation of MACT standards
  • Provides a scalable and flexible risk management
    tool, as envisioned by the Integrated Urban Air
    Toxics Strategy, to
  • Support monitoring activities,
  • Identify risks,
  • Focus resources,
  • Prioritize corrective actions, and
  • Track progress toward risk reduction goals.

18
4.0 RAIMI DESIGN STRATEGY
Provide A Consistent Means By Which Permitting
Authorities Could Account For And Assess
Potential Health Effects To Multiple Contaminants
From Multiple Sources, Which Are Often Subject To
Multiple Permitting Schemes, But Cumulatively
Impacting The Same Receptor Neighborhoods
Useful As A Permitting Tool To Support EPA,
State, And Local Permitting Authorities-independen
tly Or Combined-Evaluate And Demonstrate
Protectiveness Of Cross Program (e.g., RCRA, CAA,
Exempt) Permitting Decisions And Support
Holistic, Tailored Permit Strategies
Calculate And Track Risks From Literally Hundreds
Of Sources And Contaminants Based On Actual
Emissions Data. As New Or Refined Data Become
Available, It Can Be Directly Incorporated Into
The Assessment To Obtain Revised Risk Estimates
On A Real Time Basis
Provide Necessary Information To Prioritize And
Identify Solutions, For Sources Resulting In
Unacceptable Risks, At A Community Level Of
Resolution, And Generated In A Fully Transparent
Fashion Such That Risk Levels Are Traceable To
Each Contaminant, Each Pathway, And Each Source
19
5.0 DETERMINING PROJECT OBJECTIVES
  • Guiding Factors in Determining Project Objectives
    - USABILITY and UTILITY
  • Defensible-relies on approved methods
  • Numerically correct and consistent
  • Time efficient (month vs. year timeframe to
    complete)
  • Cost efficient (tens of thousands vs. hundreds of
    thousands)
  • Flexible-analyze variations/what ifs
  • Provides interim utility (useful data for
    trending, flags potential problems, etc.)
  • Directly applicable to end users needs
  • Directly supports solution implementation

20
5.0 DETERMINING PROJECT OBJECTIVES
  • Start With the End in Mind

21
Conceptual Model
22
5.0 DETERMINING PROJECT OBJECTIVES
  • Some general examples
  • Results generated in a manner to support
    consideration of a range of risk management
    alternatives (supports solutions)
  • Provides a standardized and consistent means
    to prioritize sources based on risk impacts
    (apples to apples across different project
    areas)
  • Each elemental component of risk or modeled
    air concentration is fully traceable to the
    culpable source (attribution can be determined)
    and
  • Flexibility to be revised as new and more
    complete emissions data sets become available
    (future utility).

23
Risk - Management and Analysis Platform (RiskMAP)
Project Database
  • Emissions Characterization Component
  • Integration of Primary Emission Databases
    (DataMiner)
  • Data Quality Review and Data Extraction
    (ACCESS)
  • Air Modeling Component
  • Preprocessing of Air Modeling Inputs (AMP)
  • Execute Air Dispersion Model (ISCST3)
  • Risk Modeling Component
  • Site Assessment and Data Input Processing
    (Risk-MAP)
  • Generate Risk Results and Perform Data
    Analysis (Risk-MAP)
  • Map and Report Generation (Risk-MAP)
  • Solutions Implementation and Performance Review

24
6.0 RAIMI COMPONENTS
  • Interactive GIS Platform Architecture
  • Architecture is a good match for
    managing/analyzing/presenting multi-layer spatial
    data
  • Links major components - emissions
    characterization/air modeling/risk modeling
    components
  • Emissions Characterization
  • Hierarchy of databases to meet DQOs
  • Driven by data management capabilities -
    Dataminer
  • Air Modeling on a Universal Grid
  • Source specific single-pass approach
  • Model flexible ISCST3/Calpuff/Aermod
  • Receptor-Based Risk Modeling
  • Multi-pathway simplified exposure scenario
  • Attribution profiling (source/contaminant/pathway)
  • Oriented to supporting solutions

25
7.0 GIS PROJECT PLATFORM
  • 7.1 Advantages of the GIS Architecture as a
    Project Platform
  • Natural match for the types of spatially related
    data used in these types of assessments
  • Platform to link emissions characterization/air
    modeling/risk modeling
  • Capability to visually manage, analyze, and
    present data and results
  • Capacity to handle cumulative type assessments

26
7.0 GIS PROJECT PLATFORM
  • 7.2 GIS Platform Construct
  • ArcViewTM Version 8.2 core platform to that
    provides operating environment for required
    databases, data management operations and risk
    modeling module (RiskMAP)
  • ETD string of inter-linked database tables
    database structure and functionality designed to
    support cumulative type assessments requiring
    large capacity and high resolution of results for
    solution management
  • Risk - MAP risk modeling module calculates
    exposure pathway specific values in a spatially
    layered data environment supports capacities
    typically required of cumulative type studies
    and custom visual displaying of interim and final
    results in traditional (tabular, etc.) and mapped
    (isopleths, spatial attributes, attribution
    tracking, etc.) formats to support solution
    consideration, implementation, and tracking

27
8.0 EMISSIONS CHARACTERIZATION
  • 8.1 Example Objectives Specific to Emissions
    Characterization
  • Obtain necessary data as inputs to complete air
    and risk modeling
  • Obtain resolution and quality of data to support
    source-specific prioritization and decision
    making
  • Identify and track key source attributes to
    support trending analysis
  • Support attribution profiling (source/contaminant/
    exposure pathway)

28
8.0 EMISSIONS CHARACTERIZATION
  • 8.1 Approach to Emissions Characterization
  • Utilize and cross reference all available
    emissions data sources (national, state, hard
    copy files) to obtain the most complete and
    accurate emissions characterization possible
  • Thoroughly research emissions databases to gain a
    better understanding of their usability
  • What are the reporting requirements and
    specifications?
  • What QC checks are performed, and who conducts
    them?
  • For what purpose is the data typically used?
  • How is missing data handled?

29
8.0 EMISSIONS CHARACTERIZATION
  • 8.1 Approach to Emissions Characterization
  • Digest available electronic emissions databases
    to evaluate if data meet completeness and quality
    requirements
  • Data needs for source-specific air and risk
    modeling parameters
  • DQOs for source-specific air and risk modeling
    parameters
  • Effectively manage data to ensure integrity of
    modeled results that are traceable to unique
    modeled sources
  • Link emissions data to GIS capabilities of air
    and risk modeling components
  • Track emission source attributes (e.g. permit
    status, source type, permit limits, enforcement
    history, etc.) to support trending analysis

30
8.1 EMISSIONS CHARACTERIZATION
  • 8.2 Emissions Data Needs
  • Source-Specific Parameter Values Required to
    support completion of air modeling component on a
    source-specific basis. Must comply with DQOs for
    air modeling inputs.
  • Speciated Emission Rates Required for accurate
    risk modeling, solution implementation, and
    attribution profiling. Generic contaminant
    groupings (total VOCs, gasoline, crude oil, etc.)
    may compromise project objectives.
  • Source-Specific Attributes Required to support
    trending analysis and possibly solution
    implementation. Examples may include permit
    status, source type, industry type, enforcement
    history, facility ID, SCC, etc.

31
8.0 EMISSIONS CHARACTERIZATION
8.2 Emissions Data Needs
32
8.0 EMISSIONS CHARACTERIZATION
  • 8.3 Emissions Data Sources
  • Important Consideration for Use Most, if not
    all, available emissions databases are not
    designed to support risk analysis
  • Emissions databases are designed to meet specific
    regulatory reporting requirements, and therefore,
    vary with respect to structure, content, and
    terminology.
  • Data source formats
  • Digital large data sets can be readily
    incorporated into the study
  • Hard copy individual regulatory files or
    facility records may provide critical missing
    data for some sources

33
8.0 EMISSIONS CHARACTERIZATION
  • 8.3 Emissions Data Sources
  • To combat terminology issues across data sources,
    the following definitions can be used
  • Individual Sources those sourcesgenerally
    industrial stack or fugitive sourcesfor which
    the available emissions inventories DO provide
    complete data sets to support source-specific air
    dispersion and risk modeling. (Typically subject
    to regulatory reporting requirements)
  • Grouped Sources those sourcesgenerally small
    stack, fugitive, and mobile sourcesfor which the
    available emissions inventories DO NOT provide
    complete data sets to support source-specific air
    dispersion and risk modeling. (Typically not
    subject to regulatory reporting requirements)

34
8.0 EMISSIONS CHARACTERIZATION
35
8.0 EMISSIONS CHARACTERIZATION
  • 8.3 Emissions Data SourcesIndividual Sources
  • State - Texas Point Source Database (PSDB)
  • Repository for an annual survey of facilities
    that meet the TNRCC emissions inventory rule.
    1997 PSDB data used in RAIMI Pilot Study.
  • Contains the source-specific values necessary for
    air and risk modeling, meeting RAIMI
    requirements.
  • Includes many other pertinent source attributes
    of interest (SCC, actual and allowable emission
    rates, emissions history).
  • Reviewed by State.
  • NTI incorporates a version of the Texas PSDB as
    its source of Texas point source emissions data.

36
8.0 EMISSIONS CHARACTERIZATION
  • 8.3 Emissions Data SourcesGrouped Sources
  • National Toxics Inventory (NTI) Area/Mobile
  • Incorporates emissions estimates of sources that
    are too small or diffuse to fall under CAA
    emissions reporting requirements (e.g., dry
    cleaners, gas station)
  • Organizes data by area and mobile source
    subcategories, which can be prioritized for
    evaluation on the basis of occurrence of the
    surrogate (e.g. railroad miles) within an
    assessment area.
  • Emissions factors used to develop estimates are
    well documented.
  • NTI data is reviewed by States, industry, and
    other federal agencies.

37
8.0 EMISSIONS CHARACTERIZATION
  • 8.3 Emissions Data Sources
  • Other Sources
  • In addition to the State and NTI databases,
    emissions characterization data can be
    supplemented through other sources, including
  • EPA files Permit applications, trial burn
    reports, etc.
  • State files Check confidential files.
  • On Paper Emission rate data is public
    information
  • In Reality Once a submittal is stamped
    Confidential, the emissions rate most likely
    does not make it into the database
  • Resolution Manual review of confidential files
    in State offices

38
8.0 EMISSIONS CHARACTERIZATION
  • 8.4 Database Tool A Helping Hand
  • DATAMINER A large database client-server
    processing system that facilitates the assembly
    of multi-source emissions inventories for air and
    risk modeling by
  • Enabling the creation and editing of database
    table relationships and views for complete access
    to all emissions attributes maintained in the
    database
  • Linking source-specific parameters necessary for
    air and risk modeling from multiple database
    tables through the Data Organizer function
  • Extracting the source-specific data sets through
    the construction and execution of simple or
    complex data queries in the Query Builder
    function

39
8.0 EMISSIONS CHARACTERIZATION
  • 8.5 Database Issues
  • Generally will not prevent completion of a
    successful localized assessment
  • Awareness of critical issues is important
  • Maintain focus on project objectives
  • Various options (e.g., bounding assessments) can
    be employed to get a idea as to risk-based
    significance

40
8.0 EMISSIONS CHARACTERIZATION
  • 8.5 Database Issues
  • Inventory Completeness Example
  • Different reporting requirements can result in
    substantially different content
  • For example, the 1997 PSDB and TRI indicate the
    following
  • Do not conclude that PSDB is more complete than
    TRI!

41
8.0 EMISSIONS CHARACTERIZATION
  • 8.5 Database Issues
  • Inventory Completeness (cont.)
  • PSDB butadiene emissions at Ameripol Synpol are
    less than the TRI emissions
  • Applying the TRI emission value to the source(s)
    at Ameripol Synpol is one option for evaluating
    the risk-based significance of this data gap

42
8.0 EMISSIONS CHARACTERIZATION
  • 8.5 Database Issues
  • Speciation Example
  • 1997 PSDB reports in the RAIMI Pilot Study
    assessment area
  • 5,668 tpy of speciated emissions (58)
  • 4,135 tpy of unspeciated emissions (42)
  • Pilot Study results based on speciated emissions
  • Not a Pilot Study objective to speciate emissions
  • To determine significance of the data gap, the
    speciated emissions could be proportionately
    increased to account for the unspeciated
    emissions
  • Applying this bounding emission rate to the risk
    model may help to establish the risk-based
    significance of unspeciated emissions.

43
8.0 EMISSIONS CHARACTERIZATION
  • 8.5 Database Issues
  • Speciation (cont.)
  • TNRCC emissions inventory program instructs
    facilities to provide speciation data for 90
    percent of HAP emissions for those sources with
    emissions rates greater than 1 tpy, or 0.1 tpy
    for any individual HAP.
  • Adherence to these instructions by facilities
    reporting emissions to the PSDB would
    significantly improve the speciationand thus
    usabilityof the PSDB for risk management
    purposes

44
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Source Selection
  • Identifying emissions sources for modeling
  • Individual Sources
  • In Pilot Study, 113 of 1,529 individual sources
    were modeled (generally, sources with greater
    than 1 tpy of a speciated contaminant).
  • Sources were prioritized based on mass of toxic
    emissions.
  • Air and risk modeling was conducted in groups of
    10-20 sources.
  • Prioritization refined based on toxicity and
    proximity of receptor neighborhoods through
    iterative modeling of prioritized groups.
  • Based on pilot study, prioritization of
    individual sources discontinued in favor of using
    more robust modeling capabilities to evaluate all
    sources in the assessment area.

45
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Source Selection
  • Grouped Sources
  • For each grouped source subcategory, construct a
    worst-case hypothetical emissions scenario that
  • County-wide emissions estimates are allocated to
    the smallest census tract
  • Air and risk modeling is conducted specific to
    each subcategory
  • Those subcategories that exceed the screening
    threshold are prioritized for additional modeling
  • For prioritized grouped subcategories
  • Allocate emissions estimates to census
    tract-level estimates for each census tract,
    utilizing the appropriate allocation scheme
  • Prioritize these results based on air and risk
    modeling for each grouped emissions subcategory

46
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Special Topics
  • Actual vs. Allowable Emission Rates
  • Modeling only allowable emissions will not
    provide a worst-case result, as most emissions
    sources are not permitted and allowable rates are
    generally not provided for grandfathered or
    exempt sources.
  • Modeling only actual rates may underestimate
    potential risk in some cases by not including
    emissions from permitted sources identified in
    the PSDB known to be operating, but with no
    reported actual emissions
  • Actual and allowable rates may be used to fill
    emission rate gaps.
  • Modeling of allowable rates for permitted sources
    may provide important information to better
    support or assess regional permitting and
    cross-program permitting

47
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Special Topics
  • Accounting for Process Upsets Maintenance
  • PSDB Actual emissions do not include Upset
    Maintenance event emissions
  • State may require UM emissions to be reported,
    but as a separate emission rate
  • In 1997 in Jefferson County, there were 38,605
    tons of pollutants released during UM events
    that are not listed as actual emissions in the
    State PSDB
  • Applying UM emissions .?

48
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Special Topics
  • Sensitivity of Source Location on Modeled Impacts
  • Example Monitoring station T-136, located in
    the Port Neches/Nederland neighborhood, is
    located about 750 meters west of a modeled
    1,3-butadiene source (wastewater pond).
  • Result A RAIMI modeling analysis of this source
    indicates that if the source location was
    actually adjusted by as little as 200 meters, the
    resulting impact at the T-136 location increases
    by a factor of two.

49
8.0 EMISSIONS CHARACTERIZATION
  • 8.6 Special Topics
  • What If TRI Was the Only Data Available?
  • TRI data is facility-specific as opposed to
    source-specific
  • Limiting assumptions must be made regarding
    source locations and source characteristics
  • Receptor impacts are highly dependent upon
    correlation of source and receptor locations
  • Potential for false negatives very high and
  • Not possible to determine numerically reliable or
    source-specific risk.
  • TRI data can be used in a generalized screen
    approach by assuming release point at facility
    boundary closest to target receptors
  • Useful to obtain better emissions data and
  • Can be used as comparison or QC check of other
    emissions databases.

50
RESULTING ENHANCEMENTS Data Miner Database
Mining Tool
  • Large capacity datasets (gigabytes)
  • Multiple source attribute handling
  • Ingest various database formats
  • Sophisticated data exporting

51
Data Miner Example Capabilities
52
9.0 AIR MODELING COMPONENT
  • 9.1 Example Objectives Specific to Air Modeling
  • Ensure adequate data are available to support
    risk modeling
  • Minimize the production of unnecessary data so
    that data management resources are not strained
  • Accommodate flexibility in the design of
    site-specific risk evaluation and management
    without the need for repetitive air modeling
    events

53
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Applies current procedures, regulatory guidance,
    data requirements, and default parameter values
  • Draft Human Health Risk Assessment Protocol for
    Hazardous Waste Combustion Facilities (HHRAP)
  • 40 CFR Part 51, Appendix W, Guideline on Air
    Quality Models (GAQM)
  • Meteorological Processor for Regulatory Modeling
    (MPRM)
  • Industrial Source Complex Short Term, version 3
    (ISCST3)
  • National Weather Service meteorological data
  • USGS/EPA Land Use (LULC) and USGS Digital
    Elevation Mapping (DEM) data

54
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Applies single-pass air modeling for each
    source
  • Up-front production of all necessary air
    modeling data to support current and anticipated
    future risk modeling needs
  • Use of unit emission rates enables one set of
    model runs for modeling each emission source to
    accommodate any combination of emissions
    scenarios (e.g., reported actual emissions,
    permitted allowable emissions, revised quantities
    of emissions due to operational changes, or
    inclusion of new contaminants in the emissions
    profile)
  • Phase-specific modeling runs for emissions
    partitioning
  • (vapor, particle, particle-bound, mercury)

55
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Special considerations of single-pass approach
  • No chemical transformation is addressed in the
    single-pass approach. However, based on a
    review of risk results for certain highly
    reactive pollutants using the single-pass
    approach, additional pollutant-specific air
    modeling may be required to implement chemical
    decay (transformation) or secondary formation of
    derivative pollutants.
  • Building downwash effects may be significant
    and should be included in the single-pass
    approach for specific sources with nearby
    receptors (within 500 meters), requiring
    gathering of additional information on the
    source and the facility not typically included
    in the emission inventory

56
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Applies universal grid
  • All data converted and stored in standardized
    geographic coordinate system (NAD 83
    Latitude/Longitude curvilinear) for quantitative
    data processing and qualitative display
  • Real-time conversion to any standard coordinate
    system for component-specific data processing
    (e.g., air model component requires UTM
    rectilinear coordinates)
  • Point-to-point spatial and scale alignment of
    layered datasets from various database caretakers
    in various coordinate systems unified into single
    universal system

57
RAIMI Air Modeling Approach
58
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Modeling of Individual Sources
  • Separate air modeling runs conducted specific to
    each individual source modeled
  • Source locations reviewed for accuracy through a
    stepwise geo-correction process (small variance -
    dramatic effect on modeled results)
  • Source-specific inputs obtained from emissions
    inventory data assignment of surrogate values
    missing physical characteristics data an option
    (except for particle density and size
    distribution)
  • A facility may define a fugitive source either as
    a stack or an area source, but in such cases, the
    physical characteristics for the source as
    reported in the emissions inventory are used in
    the air modeling without redefinition

59
9.0 AIR MODELING COMPONENT
  • 9.2 Overview of Air Modeling Approach
  • Modeling of Grouped Sources
  • Define a circle about the centroid of each
    census tract, with the area of the circle equal
    to the area of the tract
  • Place five pseudo-stack sources within each
    census tract, one at the center and one to the
    North, East, South and West at a distance of
    one-half of the radius of the circle.
  • For each pseudo-source, set ISCST3
    source-specific inputs to represent conditions
    where no plume rise occurs
  • Proportionally allocate emission rates to each
    pseudo- source (1/9th at center and 2/9th for
    four other points)

60
9.0 AIR MODELING COMPONENT
  • 9.3 Criteria for Selection of Air Model
  • Method is flexible to accommodate any air model
    that
  • Represents many different source types,
    including stacks, fugitives, flares, area and
    mobile sources
  • Supports large grid arrays covering potential
    receptors
  • Accounts for variations in local site
    characteristics, including land use and terrain
    elevations
  • Accounts for variations in hour-to-hour weather
    conditions for up to 5 years of data near the
    sources
  • Addresses dispersion, deposition and removal
    processes
  • Is widely-accepted by agencies, industry and
    public

61
9.0 AIR MODELING COMPONENT
9.3 Criteria for Selection of Air
Model Comparison of Model Capabilities
62
9.0 AIR MODELING COMPONENT
9.3 Criteria for Selection of Air Model Modeled
to Monitored Comparison
63
9.0 AIR MODELING COMPONENT
9.3 Criteria for Selection of Air Model
  • How long does it take to complete the air
    modeling?
  • Pre-processing (ISCST3/AERMOD, CALPUFF 10t)
  • 5 days Area-wide weather data acquisition and
    processing
  • 5 days Area-wide site characteristics around
    sources
  • 5 - 60 min Parameter QC and preparation for each
    source
  • Run air model (ISCST3 1 GHz P3 CALPUFF 10t)
  • 20 min Each Vapor (v,h) phase for each source
  • 2 - 4 hrs Each Particle (p,b) phase for each
    source
  • Post-processing
  • 5 min Each source for all four phases

64
9.0 Air Modeling Component
9.3 Criteria for Selection of Air Model
What about projects with different number of
sources?
65
9.0 AIR MODELING COMPONENT
  • 9.4 Air Modeling Tools
  • AMP automates labor-intensive, site-specific
    data preparation and pre-processing to facilitate
    completion of air modeling on multiple sources in
    a reasonable time period by
  • Importing GIS data for human geo-location of
    source inventory (source/facility plot files,
    land use, topo map, aerial photos)
  • Computing source-specific site parameters
    (surface roughness for 12 30-degree sectors and
    urban/rural land use to 3 km for each source)
  • Auto-generates and processes met files for 5
    years of hourly weather data for each source
  • Auto-generates ISCST3 input files for all
    four phases (v,p,b,h), including grid node array
    with terrain elevations, wet/dry deposition
  • AIR2GIS executes ISCST3 in batch mode, and
    converts plot files to format for import into GIS
    Platform for risk modeling

66
Air Model Pre-processor (AMP)
  • Windows Start Programs

67
AMP
68
9.0 AIR MODELING COMPONENT
  • 9.5 Air Modeling Inputs What is Needed and Why?
  • Source parameters location, size and buoyancy of
    gases and particles at time of release from
    source
  • Stacks predominant source type (60-90),
    requiring stack height, temperature, velocity,
    diameter, particle size distribution and density
  • Fugitives up to 1/3rd of inventory, but
    inventory typically lacks source definition, so
    assumptions are required on source size, shape
    and phase (volatiles as vapors)
  • Flares usually less than 5 of inventory,
    modeled as stacks with pseudo-diameter computed
    from heat of combustion (requires release height,
    low heat value and molecular weight)
  • Area may have significant emissions from
    estimated releases over a defined area (e.g.,
    census tracts) based on geo-political data
  • Mobile significant emissions for dense
    populations that may be treated as area sources,
    or roadway-specific line segments

69
9.0 AIR MODELING COMPONENT
  • 9.5 Air Modeling Inputs What is Needed and Why?
  • Meteorological Data
  • Surface data hourly measurements of wind
    direction, wind speed, air temperature, cloud
    cover, cloud height, precipitation amount and
    type, solar radiation and leaf area index
  • Used in air model to compute spatial and
    temporal distribution, and magnitude, of ambient
    concentrations in air (inhalable), and dry
    deposition and wet deposition at ground
    (impaction, adsorption)
  • Typically extract SAMSON data obtained from NCDC
    on CD-rom
  • Upper air data (aka, mixing height) twice daily
    measurements of wind speed and temperature
    profile in air above the surface
  • Used in air model to compute the top of the
    mixing layer above the ground, or boundary layer,
    where dispersion processes occur
  • Typically download from US EPA SCRAM web site

70
9.0 AIR MODELING COMPONENT
  • 9.5 Air Modeling Inputs What is Needed and Why?
  • GIS Data
  • Land Use Land Cover (LULC) best available
    spatial distribution of LULC should be obtained
    electronically (shapefiles) within 3 km of each
    source used for surface roughness and urban/rural
    factors
  • Source plot file shapefile with associated
    database file for every source location in UTM 83
    (and Lat/Long 83), including source parameters
    for input into Charview for geo-location and
    input files
  • USGS topographic files shapefile of topographic
    features for use in source geo-location using AMP
  • USGS DEM 90-meter (aka, 1-degree, 3 arc-second)
    files - covering maximum extent of grid node
    arrays for elevations of grid nodes
  • Aerial photographs may be useful in source
    geo-location or extracting building dimensions
  • Facility boundary files used to geo-locate
    sources on-property

71
9.0 AIR MODELING COMPONENT
  • 9.5 Air Modeling Inputs What is Needed and Why?
  • Grid Node Array (Universal Grid)
  • Coordinate System ISCST3 requires UTM
    coordinates (CALPUFF also allows
    latitude/longitude). Recommend using North
    American Datum 1983 (NAD83) for consistency
    with grid locations in USGS DEM data. Most USGS
    topographic maps are printed hardcopy in NAD27,
    which differ from NAD83 locations by about 200
    meters northerly and 50 meters easterly.
  • Grid centroid Recommend a universal grid
    centered on the grid node in the USGS DEM
    90-meter data (aka, 3 arc second, 1-degree)
    closest to the source location (NAD83). Grid
    center will be within 45 meters of the source
    location and produce air model results at the
    same locations for overlapping grid arrays from
    other sources within 20 km.
  • Coverage use every DEM grid location out to 3
    km (spacing from 6090 meters) and every 5th DEM
    grid location from 3-10 km (spacing 300-500
    meters)

72
UTM Zones (US)
73
9.0 AIR MODELING COMPONENT
  • 9.6 Special Topics on Air Modeling
  • What is the impact of chemical decay and
    secondary formation?
  • Based on chemical decay rates identified in the
    Cumulative Exposure Project (CEP), only highly
    reactive pollutants (e.g., 1,3-butadiene) decay
    (by up to 10) within 10 km. Similarly,
    secondary formation (e.g., formaldehyde) of
    pollutants only occurs within 10 km for highly
    reactive precursors (amounts up to 10). These
    values may be significant for highly toxic
    pollutants, or where large quantities of highly
    reactive pollutants are emitted.
  • What about impacts further than 10 kilometers?
  • The highest impacts from a source or group of
    sources occur within 3 km of the release and will
    be identified by the methods described. For
    impacts further than 10 km, individual grid nodes
    may be put into the ISCST3 model for specific
    Receptor scenarios of concern.

74
9.0 AIR MODELING COMPONENT
  • 9.6 Special Topics on Air Modeling
  • If the inventory only reports the facility
    location and not individual source locations,
    should we use the facility location for all
    sources and sum the emissions?
  • Only if errors of 101-103 are acceptable.
  • Results are very dependent on the source-receptor
    relationship.
  • Dilution increases exponentially from the point
    of release to the receptor. Most dilution occurs
    in the first 100-300 meters after release with
    reductions up to 1/10th of initial concentration.
    By 1-3 km from the release, air concentrations
    and deposition rates typically decrease by 10-2
    to 10-4.
  • Most facilities have property dimensions of
    several hundred meters to several kilometers.
    Errors in results will be several orders of
    magnitude due solely to the source location input
    to the model.

75
9.0 AIR MODELING COMPONENT
  • 9.6 Special Topics on Air Modeling
  • What should I do if I dont have building
    dimensions?
  • Building dimensions are almost never available in
    inventories. But, always use building data in the
    air model when it is available.
  • Building downwash affects air model results most
    significantly within 500 meters from the source.
    The impacts typically increase for taller stacks
    (about 20 meters or higher), but impacts may
    decrease for shorter stacks (less than 20
    meters).
  • When Receptors of concern are located within 500
    meters from a stack (only stacks have downwash in
    ISCST3), the air model could be run without
    building dimensions. If risk would be adverse at
    levels 101 to 102 higher than calculated without
    building downwash, and there is potential for
    building downwash based on structures near the
    stack, then building data should be obtained to
    assess impacts with downwash.

76
9.0 AIR MODELING COMPONENT
  • 9.6 Special Topics on Air Modeling
  • When should I consider using CALPUFF instead of
    ISCST3?
  • CALPUFF is an advanced, state-of-the-science air
    dispersion model that requires significant
    expertise in pre-processing the meteorological
    data prior to performing air modeling.
  • It is a non-steady-state model that tracts
    individual air parcels spatially and temporally
    for better representation of actual flows in the
    air shed.
  • Pre-processing and model execution times are
    10-100 times longer than ISCST3.
  • However, if stagnate winds (calm conditions
    occurring for extended periods), long range
    transport beyond 20-50 km, recirculation of air
    flow due to terrain or sea breeze, or regions of
    terrain above stack top are of concern, CALPUFF
    is the recommended US EPA model to address these
    issues and is compatible with the HHRAP methods.

77
9.0 AIR MODELING COMPONENT
  • 9.6 Special Topics on Air Modeling
  • What other resources are available on air
    modeling?
  • US EPA Region 6 Air Modeling Audit Checklist
  • ww.epa.gov/earth1r6/6pd/rcra_c/protocol/audit.p
    df.
  • US EPA Region 6 Sensitivity Analysis of Air
    Modeling Parameters
  • www.epa.gov/earth1r6/6pd/rcra_c/protocol/analys
    is.pdf
  • US EPA Air Quality Models (and mixing height
    data)
  • www.epa.gov/ttn/scram/

78
10.0 RISK MODELING COMPONENT
  • 10.1 Example Objectives Specific to Risk Modeling
  • Results generated in a timely and interactive
    manner so as to actually be useful in day-to-day
    permitting, planning, and enforcement activities
    (being in a position to effectively work with
    regulators, industry, and public to address
    exposure priorities and implement solutions)
  • Results generated at a level of resolution and
    traceability to serve as an asset to stakeholders
    needing to evaluate and implement solutions
    (source-specific decision making)
  • Provide a standardized and consistent means to
    conduct risk-based assessment and prioritization
    of multiple emissions sources of multiple
    contaminants from multiple facilities
  • Provide readily accessible risk-based
    prioritization tools and project platform
    designed to address multi-media solutions to
    environmental problems
  • Capacity to calculate and track potential risks
    from hundreds of sources in a fully transparent
    manner

79
10.0 RISK MODELING COMPONENT
  • 10.2 Overview of Risk Modeling Approach
  • Applies existing and current risk procedures,
    equations, and default parameter values
  • Draft Human Health Risk Assessment Protocol for
    Hazardous Waste Combustion Facilities (HHRAP)
  • Methodology for Assessing Health Risks Associated
    with Multiple Pathways of Exposure to Combustor
    Emissions
  • Risk Assessment Guidance for Superfund Volume
    IHuman Health Evaluation Manual (RAGS)
  • Exposure Factors Handbook
  • Integrated Risk Information System (IRIS)

80
10.0 RISK MODELING COMPONENT
  • 10.2 Overview of Risk Modeling Approach
  • Implements true receptor-based approach
  • Focuses on defining impacts to target receptor
    locations or neighborhood area.
  • Each target neighborhood can have customized
    exposure inputs that may influence results,
    management decisions, and communication.
  • Structure allows data to be generated and managed
    at the neighborhood or receptor level while
    maintaining coverage over large geographic areas
    (e.g., county, state, region).
  • Foundation of the dynamic project platform.

81
10.0 RISK MODELING COMPONENT
  • 10.2 Overview of Risk Modeling Approach
  • Applies simplified exposure scenarios
  • For example, default exposure assumptions and
    inputs for inhalation pathway based on an
    individual breathing outdoor air concentrations
    24 hours per day, 350 days per year
  • Pathway driven (e.g., inhalation)
  • Does not include indoor air
  • Does not include micro-exposure activity patterns

82
10.0 RISK MODELING COMPONENT
  • 10.2 Overview of Risk Modeling Approach
  • Utilizes true GIS Architecture
  • Risk Modeling component fully integrated within
    GIS environment direct linkage to Emissions
    Characterization and Air Modeling Components
  • Capability of tracking source attributes e.g.,
    emission scenario, location, source type, permit
    status, etc.
  • Capability of attribution profiling e.g.,
    contaminant, pathway, source
  • Effective management of macro and micro data sets
  • Increased capacity through efficiency and
    automation
  • Significant flexibility to modify or replace risk
    modeling inputs (pathway, receptor, source, FT,
    toxicity) to tailor the risk modeling to
    site-specific conditions and concerns

83
10.0 RISK MODELING COMPONENT
  • 10.3 Criteria for Selection of Risk Modeling
    Tools
  • Risk model selection focuses on the ability to
  • Directly import air parameter values from air
    model
  • Implement multi-pathway exposure setting
    (scenarios) with flexibility to add or delete
    pathways
  • Provide attribute tracking capabilities
  • Capacity to calculate and track risks from
    multiple (hundreds) sources and contaminants
    specific to each exposure pathway and location
    (attribution profiling)

84
10.0 RISK MODELING COMPONENT
  • 10.3 Criteria for Selection of Risk Modeling
    Tools
  • Risk model selection focuses on the ability to
  • Interchange source-specific emission rate
    scenarios
  • Customize exposure parameter input values
    specific to each receptor location or
    neighborhood
  • Manage changes to fate and transport or toxicity
    parameter input values specific to site and
    contaminant
  • Support expanded presentation and graphical
    evaluation of risk results
  • Flexible, integrates with other software
    components and tools capacity to handle very
    large amounts of data (gt2GB)

85
10.0 RISK MODELING COMPONENT
Comparison of Risk Model Capabilities
86
10.0 RISK MODELING COMPONENT
  • 10.4 Risk Modeling Tools Being Implemented
  • Project Platform - RiskMAP (ArcView V8.2)
  • Import air dispersion modeling data
  • Support receptor based approach
  • Perform multi-pathway risk calculations
  • Direct and full GIS functionality and
    presentation
  • Confirm source locations and other spatial
    queries
  • Present risk results/map generation
  • Manage and update supporting background maps
  • Supporting Tools - ACCESS/Excel
  • Interact with smaller databases
  • Perform non-complex calculations and data queries
  • Format data outputs or extract specific results

87
10.0 RISK MODELING COMPONENT
10.4 Risk Modeling Tools
  • How long does it take? (Based on 100 emission
    sources)
  • Pre-processing (Set up project files and import
    data)
  • 1 d Import air modeling output
  • 2 d Import emissions data/background maps
  • 5 d Receptor analysis/define receptor target
    areas
  • 1 d Import site characterization data
  • Run risk model (800 MHz P3 256K RAM)
  • seconds Total run time
  • Post-processing for GIS presentation
  • seconds Export all risk reports and mapping

88
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • Emissions Characterization Data
  • Facility and source-specific attributes
  • Examples include Facility SIC, source type,
    production description, process type, permit
    status, permit type, etc.
  • Required to support trending analysis,
    attribution profiling, risk management
    objectives, source prioritization
  • Speciated source-specific emissions data
  • Units - mass per unit time requirement of one
    pass air modeling approach
  • Emission rate speciated to individual chemical or
    CAS level (i.e., no generic groupings or
    mixtures)

89
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • Air Modeling Output Data
  • Pre-processed AIR2GIS file
  • Source-specific unitized air dispersion modeling
    parameters and facility and source-specific
    attributes
  • Source-specific universal receptor grid node
    array

90
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • Exposure and Site-Specific Parameters
  • Implementation of HHRAP defaults
  • Examples inhalation and consumption rates,
    exposure duration, direct and indirect exposure
    pathways, quantity and type of food ingested by
    livestock, percent contaminated
  • Parameters without HHRAP defaults
  • Average annual evapotransporation, irrigation,
    rainfall, runoff and windspeed
  • Flexibility to include site-specific data at a
    regional, neighborhood or location specific level.

91
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • Fate and Transport Parameters
  • Implementation of HHRAP defaults
  • Flexibility to incorporate site-specific data
  • Flexibility to add additional contaminants

92
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • Toxicity Parameters
  • Incorporation of IRIS, NCEA Values, HEAST
  • Flexibility to add new or updated values
  • Inhalation Pathway exposure air concentrations
    are combined with inhalation toxicity factors
    (RfC or URF) to estimate noncarcinogenic hazards
    and carcinogenic risks, respectively.

93
10.0 RISK MODELING COMPONENT
  • 10.5 Risk Modeling Inputs What is Needed and
    Why?
  • GIS Data Background Maps
  • Land Use Land Cover (LULC) provide land use
    characteristics for use in identifying
    neighborhoods, exposure scenarios, and exposure
    scenario locations.
  • USGS topographic files provide additional
    attribute information including elevations,
    roads, water features, and general facility
    boundaries.
  • Aerial photographs used in combination with
    LULC and topographic maps. Aerials are usually
    more current and are used to confirm and update
    information from other background maps.
  • Facility boundary files used to identify
    facilities, boundaries and helpful when verifying
    source locations.

94
10.0 RISK MODELING COMPONENT
  • 10.6 Special Topics on Risk Modeling
  • When should I consider using ACCESS or EXCEL as a
    risk model?
  • Building simple exposure equations/models or
    analyzing results from small projects
  • Performing validation or QC checks
  • Plotting small scale isopleths
  • Consideration of specialty exposure scenarios
    (e.g., dermal exposure)

95
How to Use Results
10.0 RISK MODELING COMPONENT
  • 1. Conduct Risk-Based Prioritizations
  • RAIMI can be used to conduct risk-based
    prioritizations specific to contaminants,
    facilities, emission sources, and data gaps.
  • For example, Pilot Study results indicate for a
    profiled neighborhood
  • 1,3-Butadiene is a risk concern
  • Identified emission sources at the Huntsman and
    Ameripol Synpol facilities are the most
    significant known contrib
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