Title: RAIMI A Practical Approach for Implementing Cumulative Type Assessments on a Localized Scale
1RAIMI - A Practical Approach for Implementing
Cumulative Type Assessments on a Localized Scale
- U.S. EPA Region 6
- Multimedia Planning and Permitting Division
- Chicago 2002
21.0 INTRODUCTION AND OVERVIEW
- 1.1 Introductions
- U.S. EPA Region VI
- U.S. EPA Region V
- Participants
31.0 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
41.0 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
52.0 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
62.0 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
72.0 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
83.0 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)
93.0 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
104.0 RAIMI - Regional Air Impact Modeling
Initiative
- Risk-based Prioritization Tool and Platform to
Develop Multi-media Solutions to Environmental
Problems
114.0 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.
124.0 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
14RESIDUAL 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 ??)
15INTEGRATED 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
16NATIONAL-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
174.0 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.
184.0 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
195.0 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
205.0 DETERMINING PROJECT OBJECTIVES
- Start With the End in Mind
21Conceptual Model
225.0 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).
23Risk - 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
246.0 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
257.0 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
267.0 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
278.0 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)
288.0 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?
298.0 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
308.1 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.
318.0 EMISSIONS CHARACTERIZATION
8.2 Emissions Data Needs
328.0 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
338.0 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)
348.0 EMISSIONS CHARACTERIZATION
358.0 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.
368.0 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.
378.0 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
388.0 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
398.0 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
408.0 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!
418.0 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
428.0 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.
438.0 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
448.0 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.
458.0 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
468.0 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
478.0 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 .?
488.0 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.
498.0 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.
50RESULTING ENHANCEMENTS Data Miner Database
Mining Tool
- Large capacity datasets (gigabytes)
- Multiple source attribute handling
- Ingest various database formats
- Sophisticated data exporting
51Data Miner Example Capabilities
529.0 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
539.0 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
549.0 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)
559.0 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
569.0 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
57RAIMI Air Modeling Approach
589.0 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
599.0 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)
609.0 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
619.0 AIR MODELING COMPONENT
9.3 Criteria for Selection of Air
Model Comparison of Model Capabilities
629.0 AIR MODELING COMPONENT
9.3 Criteria for Selection of Air Model Modeled
to Monitored Comparison
639.0 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
649.0 Air Modeling Component
9.3 Criteria for Selection of Air Model
What about projects with different number of
sources?
659.0 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
66Air Model Pre-processor (AMP)
67AMP
689.0 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
699.0 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
709.0 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
719.0 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)
72UTM Zones (US)
739.0 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.
749.0 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.
759.0 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.
769.0 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.
779.0 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/
7810.0 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
7910.0 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)
8010.0 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.
8110.0 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
8210.0 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
8310.0 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)
8410.0 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)
8510.0 RISK MODELING COMPONENT
Comparison of Risk Model Capabilities
8610.0 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
8710.0 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
8810.0 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)
8910.0 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
9010.0 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.
9110.0 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
9210.0 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.
9310.0 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.
9410.0 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