United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-454/R-00-017
April 2000
Air
& EPA
USER'S GUIDE FOR THE ASSESSMENT SYSTEM
FOR POPULATION EXPOSURE NATIONWIDE
(ASPEN, VERSION 1.1) MODEL
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DISCLAIMER
The information in this document has been reviewed in accordance with the U.S. EPA administrative review
policies and approved for publication. Mention of trade names or commercial products does not constitute
endorsement or recommendation for their use.
The following trademarks appear in this document:
UNIX is a registered trademark of AT&T Bell Laboratories.
SUN is a registered trademark of Sun Microsystems, Inc.
11
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CONTENTS
1.0 INTRODUCTION 1-1
1.1 BACKGROUND 1-1
1.2 MODEL OVERVIEW 1-1
1.2.1 Input Data Requirements 1-3
1.2.2 Computer Hardware Requirements 1-4
1.3 HOW TO USE THE ASPEN MODEL 1-4
1.3.1 Novice Users 1-4
1.3.2 Experienced Modelers 1-4
1.3.3 Management/Decision Makers 1-5
1.3.4 Programmers/System Analysts 1-5
2.0 ASPENA DISPERSION MODULE DESCRIPTION 2-1
2.1 POINT SOURCE EMISSIONS 2-1
2.1.1 The Gaussian Sector Average Equation 2-1
2.1.2 Wind Speed Profile 2-2
2.1.3 Plume Rise Formulas 2-2
2.1.3.1 Stack-tip Downwash 2-3
2.1.3.2 Buoyancy and Momentum Fluxes 2-3
2.1.3.3 Unstable or Neutral - Crossover between Momentum and Buoyancy 2-3
2.1.3.4 Unstable or Neutral - Buoyancy Rise 2-4
2.1.3.5 Unstable or Neutral - Momentum Rise 2-4
2.1.3.6 Stability Parameter 2-5
2.1.3.7 Stable - Crossover between Momentum and Buoyancy 2-5
2.1.3.8 Stable - Buoyancy Rise 2-5
2.1.3.9 Stable - Momentum Rise 2-5
2.1.3.10 All Conditions - Distance Less Than Distance to Final Plume Rise 2-6
2.1.4 Dispersion Parameters 2-7
2.1.5 The Vertical Term 2-8
2.1.6 The Decay Term 2-9
2.1.7 Building Wake Effects 2-10
2.2 AREA SOURCE EMISSIONS 2-10
2.3 DRY DEPOSITION 2-11
2.4 THE WET DEPOSITION MODULE 2-13
2.5 SECONDARY SPECIES FORMATION 2-14
3.0 MAPPING MODULE (ASPENB) DESCRIPTION 3-1
3.1 ASPENB OUTPUT FILE STRUCTURE AND UPDATE PROCEDURE 3-1
3.2 INTERPOLATING TO CENSUS TRACT CENTROIDS 3-1
3.2.1 Interpolating to Non-Resident Census Tract Centroids 3-2
3.2.2 Concentration/Deposition Estimates for the Resident Census Tract 3-6
3.2.2.1 Major Point Sources 3-6
in
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3.2.2.2 Interpolation for Motor Vehicle and Area Sources 3-8
3.3 DETERMINATION OF IMPACTED CENSUS TRACTS 3-11
4.0 DISPERSION MODULE (ASPENA) USER'S INSTRUCTIONS 4-1
4.1 MODELING OPTIONS 4-2
4.1.1 Dispersion Options 4-3
4.1.2 Source Options 4-3
4.1.3 Receptor Options 4-4
4.1.4 Meteorological Options 4-4
4.2 ASPENA INPUTS 4-4
4.2.1 Emission/Control File 4-4
4.2.1.1 Run Information, Species Types and Deposition Options 4-5
4.2.1.2 Reactive Decay Rate Inputs 4-7
4.2.1.3 Source Types and Locations 4-7
4.2.1.4 Source Release Parameters 4-8
4.2.1.5 Emission Rates 4-8
4.2.1.6 Secondary Compounds 4-9
4.2.1.7 Deposition Rates 4-9
4.2.2 STAR Meteorological Data File 4-9
4.2.3 Meteorological Index File 4-10
4.2.3.1 Temperatures 4-10
4.2.3.2 Mixing Heights 4-10
4.2.3.3 Precipitation 4-11
4.2.4 Polar Receptor Grid Network 4-11
4.3 ASPENA OUTPUTS 4-11
4.4 RUNNING ASPENA 4-12
5.0 ASPENB USER'S INSTRUCTIONS 5-1
5.1 ASPENB INPUTS 5-2
5.1.1 Source Concentration and Deposition File 5-3
5.1.2 Census Tract Data File 5-4
5.1.3 Census Tract Index File 5-4
5.2 ASPENB OUTPUTS 5-6
5.3 RUNNING ASPENB 5-6
5.4 MODEL RE-START CAPABILITY 5-9
6.0 POST-PROCESSING MODEL OUTPUTS 6-1
6.1 GENERATING CONCENTRATIONS FOR THE SECONDARY
COMPOUNDS 6-2
6.2 CALCULATING ANNUAL AVERAGE CONCENTRATIONS 6-3
6.3 EXTRACT AND TABULATE ANNUAL AVERAGE CONCENTRATION 6-4
7.0 COMPUTERNOTES 7-1
IV
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7.1 MINIMUM HARDWARE REQUIREMENTS 7-1
7.2 COMPILING AND RUNNING ASPEN ON A UNIX WORKSTATION 7-1
7.2.1 Modifying the Array Limits 7-3
7.3 PORTING THE MODEL TO THE OTHER HARDWARE
ENVIRONMENTS 7-4
7.3.1 PC 7-4
8.0 ASPEN MODEL TUTORIAL 8-1
8.1 EXAMPLE 1 - GASEOUS HAPs 8-1
8.1.1 Setting up the Emission/Control Input File for Point Sources 8-1
8.1.2 Setting up the Emission/Control Input File for Mobile Sources 8-3
8.1.3 Setting up the Emission/Control Input File for Area Sources 8-4
8.1.4 Running ASPENA 8-4
8.1.5 Running ASPENB 8-10
8.1.6 Post-Processing Model Output 8-11
8.2 EXAMPLE 2 - PARTICIPATE HAPs 8-15
9.0 REFERENCES 9-1
APPENDIX A ASPENA SUBROUTINE DESCRIPTIONS A-l
APPENDIX B ASPENA COMMON BLOCKS B-l
APPENDIX C INPUT AND OUTPUT FILE FORMATS C-l
C.I DESCRIPTION OF ASPEN INPUT FILE CONTENT AND FORMAT C-l
C.I.I Description of Emission/Control File C-l
C.I.2 Description of Meteorological Index File C-2
C.I.3 Description of STARData C-2
C.I.4 Description of Census Tract Index File C-3
C.I.5 Description of Census Tract Data C-4
C.2 DESCRIPTION OF ASPEN OUTPUT FILE CONTENT AND FORMAT C-4
C.2.1 Description of Normalized Source Concentration/Deposition File C-4
C.2.2 Description of Population Concentration/Deposition File C-5
C.2.3 Description of Source Listing File C-6
C.2.4 Description of the Listing File C-6
C.3 DECAYRATES BY REACTIVITY CLASS C-7
APPENDIX D GLOSSARY D-l
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FIGURES
Figure Page
Figure 1-1 Flow diagram of the ASPEN modeling system 1-2
Figure 3-1 ASPENB receptor grid and census tract centroids 3-2
Figure 3-2 Interpolation to non-resident tract centroids 3-3
Figure 3-3 (a) Resident tract spatial averaging for point sources 3-7
Figure 3-3 (b) Resident tract spatial averaging for point sources 3-8
Figure 3-4 (a) Resident tract spatial averaging for area and mobile sources 3-9
Figure 3-4 (b) Resident tract spatial averaging for area and mobile sources 3-10
Figure 4-1 Flow diagram of the ASPENA dispersion module 4-1
Figure 4-2 Example ASPENA run stream file (filename: aspena.sys) that creates a testing
file 4-12
Figure 4-3 Example ASPENA run stream file (filename: aspena.sys) that does not create a
testing file 4-13
Figure 4-4 Example ASPENA job file 4-13
Figure 5-1 Flow diagram of the ASPENB mapping module 5-1
Figure 5-2 Example MKTRACTS fob file 5-6
Figure 5-3 Example of ASCII formatted census tract data 5-6
Figure 5-4 Example ASPENB run stream file 5-7
Figure 5-5 Example ASPENB run stream file using the rerun feature 5-8
Figure 5-6 Example ASPENB job file that creates intermediate output files 5-9
Figure 5-7 Example of an ASPENB re-start job file 5-10
Figure 6-1 Flow chart of the ASPEN post-processors 6-1
Figure 6-2 Example job file for the SECDAT post-processor 6-3
Figure 6-3 Example job file for the post-processor AVGDAT 6-4
Figure 6-4 Example 1 job file for the EXTRDAT post-processor 6-5
Figure 6-5 Example 2 job file for the EXTRDAT post-processor 6-5
Figure 7-1 The commands for compiling ASPENA on a UNIX workstation 7-2
Figure 7-2 The commands for compiling the ASPENB on a UNIX workstation 7-3
Figure 8-1 Example emission/control input file for point sources
(filename: aspena.tri.inp) 8-1
Figure 8-2 Example emission/control input file for on-road mobile sources
(filename: aspena.mv.inp) 8-3
Figure 8-3 Example emission/control input file for area source
(filename: aspena.ar.inp) 8-5
Figure 8-4 Run stream file for the gaseous HAPs ASPENA run
(filename: aspena.ar.sys) 8-5
Figure 8-5 Run stream file for ASPENA point run (filename: aspena.tri.sys) 8-6
Figure 8-6 Run stream file for ASPENA mobile run (filename: aspena.mv.sys) 8-6
Figure 8-7 Example of ASPENAjob file 8-6
Figure 8-8 ASPENA diagnostic file created by example area source run 8-7
Figure 8-9 ASPENA diagnostic file created by example mobile source run 8-8
VI
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Figure 8-10 ASPENA diagnostic file created by example TRI source run 8-9
Figure 8-11 ASPENB example job file 8-10
Figure 8-12 Example EXP2ASCI job file 8-11
Figure 8-13 ASPENB output population concentration/deposition file (in ASCII format)
for example run 8-12
Figure 8-14 Example post-processing job file 8-13
Figure 8-15 ASPEN output in ASCII format for the example simulation 8-14
Figure 8-16 Example ASPENA input file for point source emits particulate HAPs 8-15
Figure 8-17 ASPENA diagnostic file created by example point source run 8-16
Figure 8-18 ASPENB output population concentration/deposition file (in ASCII format)
for example point source run (for Saroad code 80141) 8-17
Figure 8-19 ASPENB output population concentration/deposition file (in ASCII format)
for example point source run(for Saroad code 80216) 8-17
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TABLES
Table Page
Table 2-1 Deposition velocities for particulate matter 2-11
Table 4-1 ASPENA file descriptions 4-2
Table 4-2 Description of the emission/control file 4-6
Table 4-3 Description of the STAR meteorological data file 4-10
Table 4-4 Description of the meteorological index file 4-10
Table 4-5 Error messages in the ASPENA log file 4-12
Table 5-1 ASPENB input and output file descriptions 5-3
Table 5-2 Description of census tract data file 5-4
Table 5-3 Description of census tract index file 5-5
Table 5-4 Error messages in the ASPENB log file 5-8
Table 7-1 ASPEN disk storage requirements for example simulation 7-1
Table 8-1 Point source data parameters entered into the emission/control input file 8-2
Table C-l Description of emission/control file C-l
Table C-2 Description of meteorological index file C-2
Table C-3 Description of STAR data C-3
Table C-4 Description of census tract index file C-3
Table C-5 Description of census tract data C-4
Table C-6 Description of normalized source concentration/deposition file C-5
Table C-7 Description of population concentration/deposition file C-6
Table C-8 Description of source listing file C-6
Vlll
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PREFACE
This user's guide provides documentation for the Assessment System for Population Exposure Nationwide
(ASPEN, Version 1.1), referred to hereafter as ASPEN. It includes a technical description of the ASPEN
algorithms, instructions for running the individual modules and a tutorial for getting started.
Version 1.0 of the ASPEN model was used in the EPA's Office of Policy's Cumulative Exposure Project. The
changes to ASPEN in version 1.1, were to make file handling more flexible and easier. None of the technical
algorithms were modified. Therefore, given the same input data, the results from versions 1.0 and versions 1.1
should be identical, although the output files are formatted somewhat differently.
IX
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ACKNOWLEDGMENTS
The authors would like to acknowledge the many contributions to the development of the ASPEN modeling
system by Systems Applications International. Gerald Anderson and Gary Lundberg developed the original
version of the Human Exposure Model, from which the ASPEN modeling system was derived. Major
contributors to development of ASPEN include the late Dr. Mary Ligocki, Gary Lundberg, Arlene Rosenbaum,
Gerard Mansell, Hans Deuel, and YiHua Wei.
Daniel Axelrad and Tracey Woodruff, both of EPA's Office of Policy, sponsored the ASPEN development as
part of the Cumulative Exposure Project.
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1.0 INTRODUCTION
The User's Guide for the Assessment System for Population Exposure Nationwide (ASPEN)
provides the technical description of the ASPEN algorithms. It includes an overview of ASPEN,
a discussion of its features, instructions for running the individual modules, and a tutorial for
getting started.
1.1 BACKGROUND
The Assessment System for Population Exposure Nationwide (ASPEN), a new version of the
Human Exposure Model (HEM), was developed as part of the Cumulative Exposure Project,
sponsored by the US Environmental Protection Agency's Office of Policy, Planning, and
Evaluation. The Cumulative Exposure Project report (Rosenbaum et al., 1998) includes
sensitivity analysis of the features of ASPEN. ASPEN was designed to efficiently estimate
outdoor concentrations and depositions of multiple pollutants emitted from a large number of
sources at a large scale (e.g., national), while reporting results at the spatial resolution of census
tracts. The number of emission sources, HAPs, and census tracts included in an analysis are
specified by the user.
As part of the ASPEN development, a number of enhancements were made to HEM. These
include:
• Modification of plume rise and dispersion parameters and formulations to assure
consistency with those in the Industrial Source Complex - Long Term Model, Version 2
(ISCLT2; EPA, 1992);
Expansion of HEM's reactive decay options;
• Incorporation of simple treatment of secondary formation of HAPs;
• Improvement of HEM's dry deposition algorithm;
• Addition of a wet deposition algorithm;
Modification of the treatment of locations near point sources;
• Modification of the treatment of area and mobile sources; and
Improvement of computational procedures to reduce run times.
1.2 OVERVIEW OF THE ASPEN MODEL
The Assessment System for Population Exposure Nationwide (ASPEN) model consists of two
modules, ASPENA and ASPENB, and a series of post-processing programs. ASPENA is a
dispersion module that estimates ambient concentration increments at a set of fixed receptor
locations in the vicinity of an emission source (i.e., the receptor grid). ASPENB is a mapping
module that interpolates ambient concentration increment estimates from the grid receptors to
census tract centroids, and sums contributions from all modeled sources. The post-processing
programs:
1-1
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• distribute background HAP concentrations by census tract (BCKGRND program),
generate the secondary compound concentrations and combine the concentrations of the
primary and secondary compounds (SEC_DAT program),
calculate the total pollution concentration from all source categories for each HAP from
the ASPENB output files (MRG_DAT program),
calculate the annual average HAP concentration (AVG_DAT program), and
• convert the concentration data files from binary to ASCII format (EXTR_DAT program).
Together, the ASPEN programs estimate annual average air toxics concentrations (in |ig/m3) at
each census tract for each of eight 3-hour time blocks for each HAP/source category
combination. The major processes of the two modules are illustrated in the flow diagram shown
in Figure 1-1.
M eteorological
data
E m issions
Source data
ASPEN A
(Section 2.0)
ASPEN B
(Section 3.0)
Post-processors
(Section 4.0)
Census
data
Annual average HAP
concentration by
census tract
Figure 1-1 Flow diagram of the ASPEN modeling system
For ease in discussion and application, the ASPEN modeling system can be examined by its two
main components: dispersion module (ASPENA) and mapping module (ASPENB).
1-2
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ASPENA - Like its predecessors, the Human Exposure Model (HEM) and the South Coast Risk
and Exposure Assessment Model - Version 2 (SCREAM2), ASPENA uses a Gaussian model
formulation and climatological data to estimate long-term average pollution concentrations. For
each source, the model calculates ground-level concentrations as a function of radial distance and
direction from the source at a set of receptors laid out in a radial grid pattern. These
concentrations represent the steady-state concentrations that would occur with constant emissions
and meteorological parameters. For each grid receptor, concentrations are calculated for each of
a standard set of stability class/wind speed/wind direction combinations. These concentrations
are averaged together using the annual frequency of occurrence of each combination (i.e., the
climatology) as weightings.
These meteorological frequency distributions are typically prepared for the entire simulation
period, usually one or more years. For ASPEN, however, meteorological data are stratified by
time of day into eight 3-hour time blocks, to preserve any characteristic diurnal patterns that
might be important in subsequent estimation of population exposure. In addition to the
climatology, other inputs to ASPEN that are specified by time block include emission rate,
mixing height, and reactive decay rates. The resulting output of ASPENA is a grid of annual
average concentration estimates for each source/pollutant combination by time block.
ASPENB - In ASPENB, the mapping module, annual average concentration estimates from
ASPENA are interpolated from the grid receptors to census tract centroids, and contributions
from all modeled sources are summed to give estimates of cumulative ambient concentration
increments in each census tract. By accounting for all identified source categories (including
background concentrations), the sum of the concentration increments should yield an estimate of
the overall concentration of each HAP within each census tract. These estimates are designed to
represent population-weighted concentration averages (each census tract represents
approximately 4000 people).
1.2.1 Input Data Requirements
The three types of inputs needed to run the ASPEN models are the emission/control file,
meteorological data files, and census tract data files.
Emission/control file - contains the selected modeling options, source parameter data
(including emission rates), and meteorological station assignments
• Meteorological data - includes the annual frequency of occurrence of each stability/wind
speed/wind direction combination (by time block), temperatures (maximum, minimum
and average), precipitation data, and mixing height (by time block) for meteorological
stations within the modeling region
1-3
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• Census tract data - contains the Federal Information Processing Standards (FIPS) code,
location of the tract centroid, hypothetical radius, and urban/rural designation of each
census tract within the modeling region
The emission control file and the meteorological data files are described in detail in Section 4.2
while the census tract data files are described in Section 5.1.
1.2.2 Computer Hardware Requirements
The computer resources required to run an ASPEN application are contingent upon the number
of emission sources and HAPs to be processed. The disk storage requirement to run a simulation
on a UNIX workstation (Sun Ultra Spare 2 / Solaris 2.5.1), using the emissions from one source
category (on-road mobile), one reactivity class (reactivity class 2 including emissions from 11
HAPs) in a single EPA region (EPA region 9) is approximately 1.3 Mbytes for ASPENA, and 2.7
Mbytes for ASPENB. It takes approximately 6 CPU hours to run both ASPENA and ASPENB
for this simulation run.
1.3 HOW TO USE THE ASPEN MODEL
1.3.1 Novice Users
Novice users are those that are new to the ASPEN model and have limited dispersion modeling
experience. These users should begin with Section 1.2 to gain a conceptual overview of the
model. Section 8 provides a brief tutorial on setting up simple input files under two example
scenarios. Once users have a basic understanding of the model, they will want to review the
ASPENA and ASPENB user's instructions, respectively, in Sections 4 and 5. Section 2 provides
a complete descriptions of the ASPENA dispersion module. Section 3 provides a detailed
description of the ASPENB mapping module. Section 6 includes a discussion of the software
used to post-process the ASPEN model output. Also, the tutorial provided will help them learn
the structure of the input files and how to review the modeling results.
1.3.2 Experienced Modelers
Modelers that are unfamiliar with the ASPEN models but experienced using dispersion models in
a variety of situations will also benefit from first reviewing the content of Section 1.2 to gain a
basic orientation to the ASPEN model. Sections 4, 5 and 6 can be used as a reference for
learning the overall capabilities of the modeling system's main components. Finally, the
Appendices provide details of the formats for the ASPEN input and output files. Experienced
modelers may also be interested in reviewing sections 2 and 3, which describe the technical
details of ASPENA and ASPENB.
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1.3.3 Management/Decision Makers
Those involved in air quality management or decision-making capacities related to dispersion
modeling will benefit most from an overview of the model, and a general introduction to the
input data needs and computer hardware requirements for running the model (Section 1.2). Upon
review of this section, managers will understand the basic capabilities of the model well enough
to judge the suitability of the model for particular applications.
1.3.4 Programmers/Systems Analysts
Programmers and systems analysts, specifically those in charge of maintaining the code or those
involved with installing the ASPEN model code on other computer systems should review
Section 7. Section 7 discusses the minimum hardware requirements to run the model, and how
to port the model to various hardware environments. They may also wish to review Section 1.2
in order to have a basic understanding of the nature and overall capabilities of the model.
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2.0 ASPENA DISPERSION MODULE DESCRIPTION
The ASPEN dispersion module estimates the ambient concentration increments at a set of fixed
receptor locations within the vicinity of the emission source. The steady-state Gaussian plume
equation is used in conjunction with diurnally stratified climatological data, including wind
speed, wind direction, and atmospheric stability, to estimate long-term average ground-level
concentrations at receptor grid locations resulting from elevated point emission sources. The
specific formulation and equations used are described in the following subsections. Unless
otherwise noted, all equations are identical to those in the Industrial Source Complex - Long
Term 2 (ISCLT2) model.
2.1 POINT SOURCE EMISSIONS
2.1.1 The Gaussian Sector Average Equation
The ASPEN modeling system uses the steady-state Gaussian plume equation in order to simulate
elevated point sources with continuous emissions. To reduce computing requirements, ASPEN
utilizes a climatological modeling approach. As with other climatological models (e.g., the
Environmental Protection Agency's (EPA) Climatological Dispersion Model (CDM) and
ISCLT), the dispersion module is supplied with a STability ARray (STAR) joint probability
matrix. A STAR matrix describes the joint frequency distribution of hourly meteorological
measurements sorted into classes, or bins, by wind speed, wind direction, and atmospheric
stability. The long-term concentration is calculated by simulating the average concentration for
each meteorological bin and summing the averages across bins, weighting each by its frequency
of occurrence.
Normally, a single STAR matrix is prepared for the entire simulation period, usually one or more
years. For ASPEN, meteorological data were prepared in 3-hour time blocks. For example,
there is a STAR matrix for the time period from 3 a.m. to 6 a.m., reflecting the relative long-term
frequency of each meteorological condition for that time of day.
Classification of the wind directions for preparation of the STAR matrix requires partitioning of
the area surrounding each source into sectors of equal angular widths. The mean annual
concentration at each receptor resulting from emissions from a single stack is obtained by
averaging over all wind directions, wind speeds and stability classes according to:
I2n
where :
1 = concentration (|ig/m3)
K = units scaling coefficient (106)
Q = pollutant emission rate (g/s)
2-1
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f = frequency of occurrence of the ith wind-speed, the j ""wind-
direction, and the kth stability category (unitless)
A9" = the sector width (radians)
R = radial distance from the point source to receptor (m)
us = mean wind speed at stack height for the ith wind-speed category and
the kth stability category, (m/s)
GZ = standard deviation of the vertical concentration distribution for the
kth stability category (m)
V = Vertical Term for the ith wind-speed and kth stability category
(unitless)
D = Decay Term for the ith wind-speed and kth stability category
(unitless)
Each of the terms above are defined and discussed briefly in the following subsections.
2.1.2 Wind Speed Profile
The stack height wind speed, us (m/s), is obtained by adjusting the observed wind speed, uref
(m/s), at a reference height, zref (m), to the stack height, hs (m), through use of the wind power
law. The equation has the form,
\P
Where p is the wind profile exponent which is dependent on both the stability category as well as
whether the source is classified as urban or rural. The default values used in the ASPEN model
are the same as those for the ISCLT2 model and are given below:
Stability Category Rural Exponent Urban Exponent
A 0.07 0.15
B 0.07 0.15
C 0.10 0.20
D 0.15 0.25
E 0.35 0.30
F 0.55 0.30
The stack height wind speed, us, has a minimum value of 1.0 m/s.
2.1.3 Plume Rise Formulas
The ASPEN model uses all plume rise calculations in the ISCL2 model (EPA, 1992). Prior to
any plume rise calculations, the physical stack height is modified in order to account for stack-tip
2-2
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downwash effects. This modified stack height, hs»» is then used in place of the physical stack
height for all subsequent plume rise calculations.
2.1.3.1 Stack-tip Downwash
The physical stack height is modified to account for stack-tip downwash effects following the
treatment of Briggs (1974):
v
h' =h +2d —-1.5 for v < l.5u
s s s u s s
s
or
where hs is the physical stack height (m), vs is the stack gas exit velocity (m/s), and ds is the stack
tip diameter (m). When stack-tip downwash is not considered, hs»*= hs.
2.1.3.2 Buoyancy and Momentum Fluxes
For most calculations involving plume rise, the buoyancy parameter, Fb (mVs3), as well as the
momentum flux parameter, Fm (mVs2), are needed. These parameters are calculated as follows:
•> •>( T
F =v2
-* m * C
S(4TS)
Where AT = Ts - Ta, Ts is the stack gas temperature (K), and Ta is the ambient air temperature
(K).
2.1.3.3 Unstable or Neutral- Crossover between Momentum and Buoyancy
The determination of whether the plume rise is dominated by momentum or buoyancy in the case
where the stack gas temperature is greater than or equal to the ambient air temperature, follows
the procedure of Briggs as outlined in the ISC Users' Guide, Section 1.1.4.3 ( EPA, 1992). A
crossover temperature difference is calculated using the following equations:
ForFb<55,
(Ar)c= 0.02977;-^
2-3
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AndforFb • *55,
, ,
(Ar)c= 0.005757;
If the difference between the stack gas and ambient temperature is greater than or equal to the
crossover temperature difference, then the plume rise is assumed to be buoyancy dominated,
otherwise it is momentum dominated.
2. 1.3. 4 Unstable or Neutral — Buoyancy Rise
When the plume rise is determined to be buoyancy dominated, as described above, then the
distance to final rise, xf (m), is determined as follows:
ForF,<55:
And for Fu • »55:
xf =
Xf =
The final effective plume height is then given by:
ForFb<55:
F
h =h' + 21.425-*
And for Fb • »55:
F*
h. =h +38.71-
b
2.1.3.5 Unstable or Neutral — Momentum Rise
When the stack gas temperature is less than or equal to the ambient air temperature, or if AT is
less than the crossover temperature, (AT)C, then the plume rise is assumed to be dominated by
momentum. The effective plume height is then given by:
2-4
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2. 1.3. 6 Stability Parameter
For stable atmospheric conditions, the stability parameter, s (s"2), is required for plume rise
calculations. In ASPEN, as in the ISCLT2 model, the stability parameter is calculated from the
following equation given by Briggs (1975):
T.
As a default approximation, »0» »z»is taken as 0.020 K/m for stability class E, and for class F,
•0* *z-is taken as 0.035 K/m.
2.1. 3. 7 Stable — Crossover between Momentum and Buoyancy
As in the case of unstable conditions, a crossover temperature difference is used to determine
whether the plume rise is buoyancy or momentum dominated for stable atmospheric conditions.
In this case the crossover temperature difference, (AT)C, is given by:
(Ar)c =o.oi9582ixVs
If the difference between stack gas temperature and ambient air temperature exceeds or equals
(AT)C, the plume rise is assumed to be buoyancy dominated; otherwise it is momentum
dominated.
2. 1.3. 8 Stable - Buoyancy Rise
For buoyancy dominated plume rise, AT exceeds (AT)C as determined above. The distance to
final plume rise, xf, is calculated as
xf =2.0715-^
Vs
And the effective plume height, he, is given by the following equation:
2. 1.3. 9 Stable — Momentum Rise
In stable conditions, if the stack gas temperature is less than or equal to ambient air temperature,
or if AT is less than the crossover temperature difference (AT)C, it is assumed that the plume rise
is momentum dominated. The effective plume height is then given as:
2-5
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IF 1
~^=
,V*J
For this case, the unstable-neutral momentum rise is also evaluated. The smaller of these results
is then used as the resulting plume height.
2.1.3.10 All Conditions - Distance Less Than Distance to Final Plume Rise
When gradual rise is to be estimated and the downwind distance from source to receptor, x, is
less than the distance to final rise, then the effective plume height is given as:
h =h +1.601 ^—
( X*
This relation is used only for buoyancy dominated plumes. In addition, if this relation results in a
plume height which exceeds the final plume rise for the appropriate condition, then the final
plume rise is used instead.
For momentum dominated plumes, stable and unstable conditions are treated separately as
follows:
a) Unstable Conditions
h. = h\
ftX
Where x is the downwind distance in meters, with a maximum value, xmax, defined by:
for 0 < Fb < 55 m4/s3
for Fb>55 m4/s3
2-6
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b) Stable Conditions
X
Here the maximum downwind distance is defined by:
Tmax = 0.5^-
The jet entrainment coefficient, Pj, is given as,
As in the case of buoyant gradual rise, the minimum of the distance-dependent momentum rise,
as calculated above, and the final rise for the appropriate condition is used for the effective plume
rise.
2.1.4 Dispersion Parameters
The standard deviation of the vertical concentration distribution, oz, for point sources is
calculated using a procedure similar to that used in the ISCLT2 model. For a rural point source,
the dispersion parameter, oz, is calculated using equations which approximately fit the Pasquill-
Gifford curves (Turner, 1970) and are of the form,
oz = axb
where x, the downwind distance, is in kilometers and oz is in meters. The coefficients a and b are
given as in Table 1-2 of the ISC2 Users' Guide (EPA, 1992) and are a function of both the
downwind distance as well as stability class.
For urban point sources, the vertical dispersion parameter is computed using the Briggs'
formulas to approximate vertical diffusion data of McElroy and Pooler (1968). Table 1-4 of EPA
(1992) gives the appropriate relations for oz as a function of stability class and downwind
distance from the source. As noted in EPA (1992), although these relations are assumed valid for
downwind distances less than 100m, concentrations calculated at receptor locations within 100m
of a source should be treated as suspect.
As in the ISCLT2 model, the ASPEN modeling system assumes a uniform lateral distribution
across sector widths and therefore does not make use of the standard deviation of the lateral
dispersion, o .
2-7
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The preceding approximations for dispersion parameters are applicable for ideal point sources.
In general, a variety of processes can affect the initial growth and evolution point source plume.
The ISC models use various treatments for consideration of many of these processes including
the initial plume dimensions, building wake and downwash effects, and buoyancy-induced
dispersion. Of these, ASPEN treats only the enhancements to the vertical dispersion parameter
due to buoyancy-induced dispersion. (Treatment of building wake and downwash effects in
ASPEN differs from ISCLT2, and is discussed in Section 2.1.7)
The current treatment of buoyancy-induced dispersion in the ASPEN modeling system follows
that of Pasquill (1976) as implemented in the ISC2 model. Buoyancy-induced dispersion
enhances the vertical dispersion due to ambient turbulence by taking into account the initial
plume dispersion caused by turbulent motion and turbulent entrainment of ambient air. Then
effective vertical dispersion, oze, is given by the following relation:
G ,„ =
where oz is the vertical dispersion due to ambient turbulence, and Ah is the plume rise due to
momentum and/or buoyancy. Note that Ah is the distance-dependent plume rise when the
receptor location is between the source and the distance to final plume rise, and is the final plume
rise when the receptor location is beyond the distance to final rise.
2.1.5 The Vertical Term
In general, the vertical term which appears in the Gaussian sector average equation includes the
effects of source elevation, receptor elevation, plume rise, limited mixing in the vertical and the
gravitational settling and dry deposition of larger particles. In the ASPEN dispersion module,
receptor elevation, as well as gravitational settling of large particles, is neglected. In addition,
dry deposition of particles is treated separately, as discussed below. The vertical term is then
given as in the ISC2 model for gases and small particles as follows:
+ exp
exp
exp
-0.5
exp
2-8
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where:
he = hs + Ah
Hl=zr-(2izi-he)
H2=zr + (2iZi-he)
H3=zr-(2izi+he)
H4=zr+(2izi+he)
zr = receptor height above ground (m)
z; = mixing height (m)
In the above equation, the infinite series accounts for the effects of restriction on vertical plume
growth at the top of the mixed layer. It should be noted that if the effective stack height, he,
exceeds the mixing height, z;, then the plume is assumed to fully penetrate the elevated inversion
and the ground-level concentrations are set to zero. At long downwind distances, the vertical
term, as defined above, changes the form of the vertical concentration distribution from Gaussian
to rectangular. Thus, the equation for the vertical term for downwind distances where the ratio of
oz/z;is greater than or equal to 1.6 is changed to the following form:
y =
A more detailed discussion of the Vertical Term, including special treatments for mixing heights
in rural and urban modes under various stability conditions may be found in the ISC2 Users'
Guide (EPA, 1992).
2.1.6 The Decay Term
The decay term is used as a simple means of accounting for the pollutant removal by physical
and/or chemical processes. The decay term takes the following form:
for V>°
for V = 0
or
D =
2-9
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where:
D = decay term (unitless)
\|/ = decay coefficient (s"1)
x = downwind distance (m)
us = wind speed at stack height (m/s)
2.1.7 Building Wake Effects
The procedures used by the ASPENA model to account for the effects of building wakes and
downwash effects are considerably different than those employed in the ISC2 model. Within the
ISC2 model, the effects of building wakes on the plume dispersion coefficients are treated in a
manner following those of Huber and Snyder. Following their suggestions, the vertical
dispersion parameters are adjusted using a vertical virtual distance which is dependent on various
factors including the relative dimensions of nearby buildings, stability class, and urban or rural
classification of the emission source.
ASPENA uses a simpler treatment which also involves adjusting the plume dispersion
parameters for a vertical virtual distance. Within ASPENA, the virtual distances are determined
using an empirical formulation involving the building cross-sectional area and stability class, but
are treated in the same way for both the rural and urban option. The formula used for calculating
the vertical virtual distance, x z, is given by,
xz =bAc
where A is the building cross-sectional area and the coefficients b, c, and d are dependent on the
stability class and are given in the following table. This virtual distance is then added to the
physical downwind distance and used through for all plume rise and dispersion parameter
calculations.
Stability Category bed
A 1.95 0.504 0.754e-08
B 2.72 0.504 0.15799e-07
C 4.05 0.511 0.156395e-06
D 4.95 0.54 0.1039e-05
E 4.95 0.54 0.1039e-05
F 4.95 0.54 0.1039e-05
2.2 AREA SOURCE EMISSIONS
The ASPEN modeling system treats area sources (including motor vehicles) as a pseudo-point
source located within each census tract. Pseudo-point sources are assumed to be vented point
sources with an effective stack height of 5 meters and for which no plume rise calculations are
made. The annual average concentration for area sources are processed within the mapping
2-10
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module (ASPENB) in one of two ways depending upon the relative area of the census tract with
respect to the location of the receptor grid locations. For large census tracts, five dispersion grids
resulting from the pseudo-point treatment are distributed symmetrically throughout the tract in
order to estimate ambient concentrations due to area source emissions. For small census tracts,
only a single dispersion grid is used, located at the census tract centroid. A more detailed
description of the treatment of area sources may be found in the discussion of the ASPENB
module.
2.3 DRY DEPOSITION
Deposition of pollutants onto surfaces has the effect of reducing the average ambient
concentrations and may be significant for particles. The dry deposition of gaseous HAPs is slow,
so for most of these species, the deposition is less important than chemical reaction as a removal
mechanism. Therefore, neglecting dry deposition for gas phase pollutants has little effect on the
modeled concentrations. The ASPEN model therefore accounts for the deposition of particulate
phase HAPs but does not include deposition of gas phase pollutants.
For particles, dry deposition rates are primarily a function of the particle size, and are thus much
larger for coarse particles than for fine particles. In addition, the deposition of coarse particles is
also highly dependent on gravitational settling. The dry deposition rates are also a function of the
land-use type and vary for urban and rural environments. Deposition velocities, Vd (m/s), for the
fine and coarse particles were obtained for different land-use types using the dry deposition
algorithms of the Variable-grid Urban Airshed Model (UAM-V) photochemical model (SAI,
1992). These values are further parameterized as functions of stability class and wind speed.
ASPEN's predicted atmospheric concentrations for parti culate matter take into account different
rates of particle deposition on urban and rural lands. The deposition velocities used in ASPENA
are shown in Table 2.1.
TABLE 2.1 Deposition velocities for particulate matter
Stability
A
B
C
D
E
F
Deposition Velocities (m/s) for coarse particles - Rural*
Wind speed (m/s)
1.5
1.33E-02
1.28E-02
1 .25E-02
1 .24E-02
1.13E-02
1.04E-02
2.5
1 .98E-02
1 .95E-02
1 .93E-02
1 .92E-02
1 .86E-02
1 79E-02
4.5
3.32E-02
3.30E-02
3.29E-02
3.29E-02
3.25E-02
3.22E-02
7.0
5.02E-02
5.01 E-02
5.01 E-02
5.00E-02
4.98E-02
4.96E-02
9.5
6.73E-02
6.72E-02
6.72E-02
6.72E-02
6.70E-02
6.68E-02
12.5
8.78E-02
8.78E-02
8.78E-02
8.77E-02
8.76E-02
8.75E-02
2-11
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Stability
A
B
C
D
E
F
Deposition velocities (m/s) for coarse particles - Urban*
Wind speed (m/s)
1.5
3.10E-02
2.99E-02
2.92E-02
2.89E-02
2.64E-02
2.42E-02
2.5
4.78E-02
4.71 E-02
4.68E-02
4.66E-02
4. 51 E-02
4.37E-02
4.5
8.27E-02
8.24E-02
8.22E-02
8.22E-02
8.13E-02
8.05E-02
7.0
1.27E-01
1.27E-01
1.27E-01
1.27E-01
1.26E-01
1.25E-01
9.5
1.71E-01
1.71E-01
1.71E-01
1.71E-01
1.71E-01
1.70E-01
12.5
2.24E-01
2.24E-01
2.24E-01
2.24E-01
2.24E-01
2.24E-01
Stability
A
B
C
D
E
F
Deposition velocities (m/s) for fine particles - Rural*
Wind speed (m/s)
1.5
5.55E-05
5.39E-05
5.29E-05
5.22E-05
4.86E-05
4.53E-05
2.5
8.48E-05
8.38E-05
8.32E-05
8.29E-05
8.06E-05
7.85E-05
4.5
1 .45E-04
1 .45E-04
1 .44E-04
1 .44E-04
1 .43E-04
1 .42E-04
7.0
2.21 E-04
2.21 E-04
2.21 E-04
2.21 E-04
2.20E-04
2.19E-04
9.2
2.98E-04
2.97E-04
2.97E-04
2.97E-04
2.97E-04
2.96E-04
12.5
3.89E-04
3.89E-04
3.89E-04
3.89E-04
3.89E-04
3.88E-04
Stability
A
B
C
D
E
F
Deposition velocities (m/s) for fine particles - Urban*
Wind speed (m/s)
1.5
1.15E-04
1.11 E-04
1 .09E-04
1 .08E-04
9.98E-05
9.25E-05
2.5
1.79E-04
1.77E-04
1.76E-04
1.75E-04
1.71 E-04
1 .66E-04
4.5
3.13E-04
3.12E-04
3. 11 E-04
3. 11 E-04
3.08E-04
3.05E-04
7.0
4.81 E-04
4.81 E-04
4.80E-04
4.80E-04
4.78E-04
4.77E-04
9.5
6.50E-04
6.50E-04
6.49E-04
6.49E-04
6.48E-04
6.47E-04
12.9
8.53E-04
8.53E-04
8.52E-04
8.52E-04
8.51 E-04
8.50E-04
*ASPEN computes particulate matter deposition rates for urban and rural lands, and also
incorporates the resulting particle removal rates into predicted air concentrations.
Within the ASPEN dispersion module the deposition of particulate phase pollutants is treated
using an equation similar to the Gaussian sector average equation. To account for dry deposition,
an additional decay term is included in the calculation of ambient concentrations while the
deposition rate, Rd, is given as,
where:
v
dry deposition rate (|ig/m2-s)
deposition velocity (m/s)
ground-level concentration (|ig/m3)
The decay rate *F for dry deposition is determined as a function of the deposition velocity, the
downwind distance from the source and the relative dimensions of the plume with respect to the
2-12
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mixing height. Both the plume dimensions and the mixing height are assumed to be dependent
on the atmospheric stability as well as time of day. The decay term associated with the dry
deposition is given as follows:
where:
^deP = decay rate for deposition
r* = 0 if 2oz < h's
= (r; - ri4)/2 where r; is the distance at which 2oz > h s
The deposition decay rate, \|/dep, is calculated from the deposition velocity and the dimensions of
the plume with respect to the mixing height as follows,
* dep
As examination of the above relations reveals, dry deposition, and hence reductions in ambient
concentration, is not considered until the plume dimensions are such that the plume impacts the
surface of the ground.
Separate decay terms are calculated in order to account for plumes which may impact urban or
rural areas, in addition to accounting for whether the pollutant source is classified as urban or
rural.
2.4 WET DEPOSITION
The ASPEN dispersion module uses the wet deposition algorithm from the revised version of the
CAP88-PC model to estimate the wet deposition of particles. The algorithm is based on the
approximate method described by Rodhe (1980, Models) and uses the fraction of time during
which precipitation is occurring in conjunction with the total annual precipitation to calculate
both the decay rate for the modeled ambient concentrations as well as the deposition fluxes.
As with the dry deposition calculations, an additional decay term is used to account for the
effects of wet deposition. In this case, the decay rate is a function of the scavenging coefficient,
X (sec"1), where the scavenging coefficient is proportional to the precipitation rate:
where p is the average annual precipitation rate, (cm/yr). Defining fp as the fraction of time that
precipitation actually occurs, then the actual average precipitation rate during periods of
precipitation becomes,
P=I7
j P
2-13
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and the scavenging coefficient is,
The decay term associated with wet deposition is then given as,
"'
While the wet deposition rate is given as,
R = n
wet 2nms wet
where:
R-wet = wet deposition rate (|ig/m2-s)
X = scavenging coefficient (sec"1)
Q = emission rate (|ig/s)
r = downwind distance from source (m)
us = windspeed (m/s)
Dwet = decay rate due to precipitation scavenging
2.5 SECONDARY SPECIES FORMATION
Many of the toxic species treated within the ASPEN modeling system are formed through
atmospheric reactions with nontoxic precursor species. The formation of these secondary species
is treated using a post-processing procedure to estimate the annual average concentration
increments. These precursor-product pairs are modeled within the dispersion module using the
appropriate precursor reactive decay rates. ASPEN calculate the secondary product
concentration as the difference between the precursor concentration in an inert model run and the
concentration in the presence of reactive decay. The resulting concentration differences are
adjusted for molar yield and molecular weight to provide an estimate for the concentration of the
secondary species.
As an example, consider the treatment of secondary acrolein production. Since butadiene is the
precursor species, two separate ASPENA runs would be performed, one with the appropriate
decay rate for butadiene (reactive run), and one with a decay rate of zero (inert run). The
concentrations of secondary acrolein are then calculated as:
acrolein ' VV butadiene mert /C butadiene reactlve )
2-14
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where:
= ambient concentration of secondary acrolein (|ig/m3)
inert = ambient concentration of butadiene for inert run (|ig/m3)
reactive = ambient concentration of butadiene for reactive run (|ig/m3)
Other secondary species concentrations are calculated similarly.
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3.0 MAPPING MODULE (ASPENB) DESCRIPTION
3.1 ASPENB OUTPUT FILE STRUCTURE AND UPDATE PROCEDURE
The ASPEN mapping module (ASPENB) produces a separate output file for each HAP/source
category combination. Each of these files contains a record for each census tract with estimates
of annual average concentrations for each of eight 3-hour time blocks. The procedure for
producing these files by ASPENB is as follows:
• As ASPENB processes the an input file of the normalized source
concentrations/depositions (ASPENA output file), each time a HAP is encountered
ASPENB checks the local directory to determine if an output file for that HAP/source
category combination already exists. If not, ASPENB creates the output file, and
initializes it by creating a record for each census tract. An initial tract record contains a
state/county FIPS and tract number, and eight concentration fields (each with a value of
zero), and two deposition fields (each with a value of zero). If an output file already
exists, it is opened.
ASPENB then proceeds with the processing of the HAP. ASPENB interpolates the
normalized concentrations/depositions of the grid receptors around the emission source to
all the census tracts which fall within the source 50 kilometers impact zone. (See
sections 3.2 and 3.3 for detailed discussions of the interpolation procedures and the
determination of impacted census tracts, respectively.) It then applies the HAP emission
rate to the normalized interpolated concentrations to obtain the population
concentration/deposition estimates. For example, if the normalized concentration from
the emission source for time block 1 at census tract A is 0.5 |ig/m3, and HAP emission
rate is 2 g/sec, the HAP concentration is 1 |ig/m3for time block 1 at census tract A.
• The HAP output file is then updated by incrementing the previous values with the current
estimates, to obtain cumulative estimates for each census tract. After the output file is
updated, it is closed.
3.2 INTERPOLATING TO CENSUS TRACT CENTROIDS
The normalized concentrations/depositions estimated by ASPEN's dispersion module
(ASPENA) for grid receptors surrounding each emission source are interpolated to the census
tract centroids within the 50 kilometers impact zone in the ASPENB. (See section 3.3 for a
detailed discussion of the determination of impacted census tracts.)
3-1
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Figure 3-1. ASPENB receptor grid and census tract centroids
Figure 3-1 illustrates the relationship between the ASPEN model receptor grid and census tract
centroids. The concentric rings represent the inner three rings of the ASPEN receptor array; and
the irregular polygons represent the census tracts. A dark circle within each polygon represents
the centroid of the tract.
The ASPENB designates the tract in which the source is located as the resident tract. Near
sources, where ambient concentration gradients are likely to be steep, the position of a tract
centroid relative to the source may result in a significant over- or underestimate of the
population-weighted average exposure concentration in the tract. The coarser the spatial resolu-
tion of the population, the more significant the uncertainty in the average exposure concentration
is likely to be. Therefore, for resident tracts, instead of estimating the ambient concentration
increment at a single point in the tract (i.e., at the centroid), the average concentration increment
over the entire area of the tract is estimated for the resident tract.
Detailed descriptions of the different interpolation procedures for the non-resident and resident
census tract centroids are provided in the following sections.
3.2.1 Interpolating to Non-Resident Census Tract Centroids
The normalized concentrations/depositions for grid receptors are interpolated to the non-resident
census tract (population) centroids with log-log interpolation in the radial direction and linear
interpolation in the azimuthal direction (see Figure 3-2). The estimates are designed to represent
average concentration for the tract. The interpolation to non-resident census tract centroids is
implemented as follows:
3-2
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Linear
P1 Px
©
Figure 3-2. Interpolation to non-resident tract centroids
For each census tract that falls within the 50 kilometer radius of the source impact zone,
calculate the distance between the census tract centroid and the source, d, and its azimuth
az (the clockwise angle measured from north).
Locate the angular (al anda2) and radial indices (rl andr2) in the receptor grid
surrounding the non-resident census tract. The angular indices are the 2 closest azimuths
of the polar receptor grid to the centroid azimuth. The radial indices are the 2 closet ring
distances of the polar grid to the centroid. For example, the default polar grid has the
following azimuths and ring distances with respect the emission source location:
3-3
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Radial Index
1
2
3
4
5
6
7
8
9
10
11
12
Radial Distance (km)
0.1
0.5
1.0
2.0
5.0
10.0
15.0
20.0
25.0
30.0
40.0
50.0
Angular Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Azimuth (Degree)
0.0
22.5
45.0
67.5
90.0
112.5
135.0
157.5
180.0
202.5
225.0
247.5
270.0
292.5
315.0
337.5
If a centroid is located at azimuth 110 degrees, and distance 0.65 km with respect to the emission
source, the angular indices are 5 (90 degree) and 6 (112.5 degree), and the radial indices are 2
(0.5 km) and 3 (1.0 km) as shown below.
• Calculate the ratios for log-log interpolation in the radial direction (rratio), and linear
interpolation in the azimuthal direction (aratio)
Ind — In radiir 1
rratio =
In radiir'i — In radiirpl
3-4
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where:
d = distance between the census tract centroid and the source
radiirl = radial distance in the receptor grid for the radial index rl
radii r2 = radial distance in the receptor grid for the radial index r2
rratio = ratio for log-log interpolation in the radial direction
aratio = a - a\
where:
a = azimuth of the census tract in the receptor scaling
al = azimuth for the angular index al in the receptor scaling
aratio = ratio for linear interpolation in the azimuthal direction
• Set the logarithm of the concentrations for each time block at the four corners of the
receptor grid surrounding the census tract
c\ = lncal,rl,/7
cl = \ncal,r2,h
c4 = Inca2,r2,h
where:
ci, C2, Cs, C4 = the logarithm of the concentrations at the four
corners of the grid for time block h
cai,ri,h, Cai,r2,h, Ca2,ri,h, Ca2,r2,h = the concentration for the receptor with indices
(al,rl), (al,r2), (a2,rl), and (a2,r2) for time block h
• Log-log interpolation in the radial direction:
ca\ = c\ + \c2 — cl) X rratio
~2 = c3 + \c4 — c3) X rratio
where:
ca1,ca2 = the logarithm of the interpolated concentrations for time block h
ci, C2, Cs, C4 = the logarithm of the concentrations at the four "corners" of the grid
for time block h
Take the exponent of the logarithm of the interpolated concentrations in the radial
direction:
cca\ = exp(cal)
cca2 = exp(ca2)
3-5
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where:
cca1,cca2 = the interpolated concentration for time block h
ca,,ca2 = the logarithm of the interpolated concentrations for time block h
• Finally, linearly interpolate in the azimuthal direction:
tc = ccai + (cca.2 — ccai) x aratio
where:
tc = concentration at the census tract centroid for time block h
cca1,cca2 = interpolated concentrations at time block h
aratio = ratio for linear interpolation in the azimuthal direction
3.2.2 Concentration/Deposition Estimates for the Resident Census Tract
The procedures for estimating concentration and deposition for the resident census tracts are
different for point sources and pseudo point sources.
3.2.2.1 Major Point Sources
For tracts with centroids close to a major point source, the ambient concentration is estimated in
ASPEN by spatial averaging of the ambient concentrations of receptors estimated to fall within
the bounds of the tracts, instead of by interpolation to the centroid. Figure 3-3 (a,b) illustrates the
spatial averaging procedure. Since inclusion of detailed information on the boundaries of the
census tracts was judged to be excessively resource-intensive, a circle of equal area to the census
tract, centered at the centroid (Figure 3-3 a), was used as an estimate of the tract boundary in the
spatial averaging procedure.
3-6
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..©—©•••©..
•©.
©
.&•
©
..©••••••©...
D.
Figure 3-3 (a) Resident tract spatial averaging for point sources.
That procedure is implemented as follows:
• For each point source, the tract with the closest centroid is determined, i.e., the resident
tract is defined.
• An effective or pseudo-radius is calculated for the resident tract based on the known tract
area and the assumption that the shape of the tract is circular.
• Each modeling receptor for the source is evaluated to determine if it falls within the
pseudo-radius of the tract.
• Based on the configuration and spacing of the modeling receptors, an area of
representation is assigned to each receptor.
• The resident tract's average outdoor concentration is calculated as the area-weighted
average of the modeling receptors that fall within its pseudo-radius (Figure 3-3b). The
calculation is shown as follows:
conck =
totarea
3-7
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Figure 3-3 (b) Resident tract spatial averaging for point sources.
where:
cowc
•it
area-weighted average concentration for time block k at the resident tract
scijk = normalized concentration for the receptor at the ith direction, jth distance
within the bound of the resident tract for time block k
ay = the area associated with the receptor at the ith direction, and jth distance
totarea = the accumulated area for the receptor grid fall within the bound of the
resident tract
If no receptor fall within the pseudo-radius of the closest tract, then the tract concentration is
estimated with the standard interpolation procedure described in Section 3.2.1.
3.2.2.2 Interpolation for Motor Vehicle and Area Sources
Each motor vehicle and area source is treated as a single pseudo-point source located at the
centroid of each census tract in the ASPEN. Outside of the resident census tract of the pseudo-
point source, resulting ambient concentration estimates are interpolated to tract centroids, as is
done for major point sources.
However, the default interpolation approach cannot be implemented within the resident census
tract, since the concentration cannot be estimated at the emission point (the tract centroid) with
the long-term Gaussian formulation. For the resident tract, ASPEN represents motor vehicle and
area sources as multiple pseudo-point sources geographically dispersed throughout the census
tract (see Figure 3-4a).
3-8
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'©..
©
... ...
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Figure 3-4 (a) Resident tract spatial averaging for area and mobile sources.
For the resident tracts with radius larger than 0.3 kilometers (the average radius of two innermost
modeling receptor rings), ambient concentrations in the resident census tract are estimated on the
basis of five dispersed pseudo- point sources in ASPEN, with spatial averaging of the ambient
concentrations of receptors estimated to fall within the bounds of the tract.
For purposes of the spatial averaging, the tract is assumed to be perfectly round (Figure 3-4a).
One of the five pseudo-point sources is located at the center of the tract. The others are located
halfway between the center and the hypothetical circumference in each of the four primary
compass directions (Figure 3-4b).
5-9
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'T®.
Figure 3-4 (b). Resident tract spatial averaging for area and mobile sources.
The area-weighted average concentration are estimated for the resident tract for the pseudo point
sources as following:
where:
sc.
-------
divm = the relative size of the receptor grid surrounding pseudo point m
to the total area for the all 5 receptor grids: 1/9 for m=l; 2/9 otherwise.
For the resident tracts smaller than 0.3 kilometers, the concentration/depositions are set to zeros.
3.3 DETERMINATION OF IMPACTED CENSUS TRACTS
The normalized concentrations/depositions estimated by ASPEN's dispersion module
(ASPENA) for grid receptors surrounding each emission source are interpolated to the census
tract centroids within the 50 kilometers impact zone in the ASPENB. The determination of
which census tracts fall within this zone is facilitated by the structure of the census tract index
and census tract data files.
The tract index file contains the state and county index data. First the state index data are listed
with the following information for each state.
State FIPS code
Maximum and minimum longitude and latitude of the state
• Total number of counties in the state
Pointer to the first county of the state, i.e., the record number of the first county of that
state in the list of all counties (to follow in the tract index file)
Next, the county index data are listed in the tract index file with includes the following
information for each county.
County FIPS code
• Maximum and minimum longitude and latitude of the county
Total number of tracts in the county
• Pointer of the first tract of the county, i.e., the record number of the first tract of that
county in the list of all tracts (in the tract data file)
For each census tract, the census tract data file contains the following:
State/County FIPS code and tract FIPS code
• Location of census tract centroid in longitude and latitude
Urban/rural designation
• Hypothetical tract radius
ASPENB finds tract data for the tracts with centroids within the 50 kilometer impact zone of
each emission source as follows:
3-11
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Check the locational parameters of each state to determine if there is a potential overlap
between that state and the 50 km radius circle of grid receptors around the emission
source.
If there is a potential state overlap, go to the records of the counties in that state and check
each for a potential overlap between the county and the 50 km radius circle of grid
receptors around the emission source.
If there is a potential county overlap, go to the tract records of the county and for each
tract determine if the centroid falls within the 50 km radius circle of grid receptors around
the emission source.
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4.0 DISPERSION MODULE (ASPENA) USER'S INSTRUCTION
ASPENA's required data inputs include HAP emission rates, modeling options, and
meteorological data. Groups of HAPs that are of the same species type (gaseous, fine paniculate,
coarse particulate), use the same reactive decay rates, and use the same dry/wet deposition
options may be simulated together in a single run. ASPENA estimates the normalized source
concentration/deposition for the receptor grid surrounding each source. The normalized
concentration/deposition estimates and HAP emission rates are then input to ASPENB, the
mapping module of the modeling system, along with the census tract data. (The HAP emission
rates are carried over from the ASPENA emission/control file to the ASPENA normalized source
concentration/deposition output file.) The final outputs from the ASPEN modeling system are
estimates of annual average concentrations (in |ig/m3) at each census tract for each of eight 3-
hour time blocks for each HAP/source category combination.
/Emission/ / y
control file / /
1 '
/Processed /
source listing /
Meteorological / / Meteorological /
index / / data /
^ r
ASPENA
1 '
/• Normalized HAPs /
concentraton/ deposition /
file /
• HAP emission rates /
Figure 4-1 Flow diagram of the ASPENA dispersion module
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A description of the input and output files of the ASPENA module are provided in Table 4-1.
Table 4-1 ASPENA file descriptions
File Name
Emission/control
Meteorological Index
STAR meteorological
data
SYS file
Normalized source
concentration and
deposition file
Source listing
File Type Description Data Contents
ASCII ASPENA input file Modeling options; reactive decay rates ;
emission rates for a group of HAPs with
the same species type, reactivity class,
and selections for dry/wet deposition;
Emission rates by stack for point sources
and by census tract for pseudo point
sources (area or mobile sources) for each
of eight 3-hour time blocks; stack
parameters for point sources
Binary ASPENA input file NWS station ID and location; annual
average temperatures (max, min, and
mean) and precipitation (avg. and
frequency); annual average mixing
heights for eight 3 -hour blocks
Direct ASPENA input file Joint frequencies of 6 wind speeds, 16
access wind directions and 6 stability categories
binary at each NWS station for each of eight 3-
hour time blocks
ASCII ASPENA run stream List of ASPENA input and output
filenames
Binary ASPENA output file Normalized concentration/deposition
(ASPENB input estimates for the polar grid receptors
file) surrounding each emission source for
each of eight 3-hour blocks; emission
rates of the associated HAPs from each
source for each of eight 3 -hour time
blocks
ASCII ASPENA output file List of processed sources used by
ASPENA (used for QA purposes)
4.1 MODELING OPTIONS
ASPEN provides the user with a range of options to meet the needs of a variety of modeling
applications. This section gives an overview of the dispersion, source, receptor and
meteorological options that are available in the ASPENA dispersion module. Section 4.2
discusses the input files in which these modeling parameters are set.
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4.1.1 Dispersion Options
The dispersion parameters in ASPENA are consistent with those in ISCLT2 (EPA, 1992), the
EPA-recommended model(when ASPEN was developed) for estimating long-term average
concentrations resulting from both rural and urban emission sources. ISCLT2 algorithms for
stack-tip downwash, buoyancy-induced dispersion, and final plume rise, and default values for
wind profile exponents and for vertical potential temperature gradients are used for ASPENA
simulations and cannot be overridden by the user.
The user can select either rural or urban dispersion parameters, depending on the characteristics
of the source location. The user also has the option of calculating dry and/or wet deposition flux
values for a simulation of particulate HAPs. Finally, the user may select to invoke ASPENA's
building downwash algorithms for point sources. However, it should be noted that these
algorithms differ from those in (see Section 2.1.7).
Note that ASPENA does not treat the effect of terrain elevation on ground-level ambient
concentration estimates, but implicitly assumes flat terrain throughout the modeling domain.
4.1.2 Source Options
ASPENA is capable of modeling three pollutant species types, two types of emission sources,
and up to ten source categories. Each of these source options are listed here.
Species types: (1) gaseous HAPs, (2) fine particulate HAPs, (3) and coarse particulate HAPs
Source types: (1) point/stacked sources and (2) pseudo point/non-stacked sources (area and
mobile sources are treated as pseudo point source in ASPEN). Detailed description of source
types, release parameters, emission rates and multiple sources is given in section 4.2.
Source categories: The emission rates of the emission sources can be aggregated into up to ten
different categories. For example, for the Cumulative Exposure Project, the following emission
source categories were used:
• Metal manufacturing point sources (CAT09)
Non-metal manufacturing point sources (CATOO)
• Petroleum refineries (CAT02)
Municipal waste combustors (CAT07)
• Hazardous waste incinerators (CAT08)
Other point sources (CAT01)
• Manufacturing area sources (CAT05)
Non-manufacturing area sources (CAT06)
• Onroad mobile sources (CAT03)
• Nonroad mobile sources (CAT04)
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The emission rates of the sources are specified for eight 3-hour time blocks in the model. The
emissions of the sources can be constant or vary by time block.
The modeled HAPs must be assigned a set of reactive decay rates that vary by stability class and
time block. A single ASPENA simulation can include emission rates for a group of HAPs with
the same species type, reactivity class, and selection of dry/wet deposition.
4.1.3 Receptor Options
Surrounding each modeled source, ASPENA uses a default polar receptor grid of 12 concentric
rings in 16 radial directions for a total of 192 receptors. The default ring distances from each
modeled source are 0.1, 0.5, 1.0, 2.0, 5.0, 10.0, 15.0, 20.0, 25.0 30.0, 40.0, and 50.0 km.
Following the caution of the ISC user's guide (EPA, 1992) that concentrations at receptors less
than 100 meters from a source may be suspect, the closest receptor distance is 100 meters. Fifty
km is the maximum distance recommended by the EPA for application of a Gaussian model
(EPA, 1992).
ASPENA also allows the user to replace the default distances with user-specified values
(between 100 meters and 50 km) for the 12 rings surrounding the modeled source.
4.1.4 Meteorological Options
ASPENA uses STability Array (STAR) meteorological data which includes joint frequency
distributions of 6 wind speeds, 16 wind directions, and 6 stability categories for each of eight 3-
hour time blocks. The user can select the STAR data to be used for a particular modeled source
by specifying the National Weather Service (NWS) station ID. If no selection is made, ASPENA
will use the STAR data from the NWS station in the data base that is nearest the source.
ASPENA allows the user to customize the meteorological data inputs by excluding specified
stability classes, wind speeds, and wind directions for a certain NWS station. If certain
meteorological parameters are excluded ASPENA will re-normalize the joint frequency
distributions for the station.
4.2 ASPENA INPUTS
The three types of input files needed to run the ASPENA dispersion model are: emission/control
file, a STAR meteorological data file, and a meteorological index file.
4.2.1 Emission/Control File
The emission/control input file allows users of ASPENA to select the appropriate dispersion,
source and receptor options in order to simulate the modeling conditions of interest. The
modeling parameters include specifying species type, source type, source location, source release
4-4
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parameters, emissions rates, and decay rates. The format of the emission/control file is provided
in Table 4-2.
4.2.1.1 Run Information, Species Types and Deposition Options
The run information, species type and deposition selections is specified in the first record of the
emissions/control input file. There are three species types in ASPEN: gaseous, fine particles,
and coarse particles. Each emission input file should include only HAPs with the same species
type, reactive decay rates, and dry/wet deposition selection. The syntax, type, and order for
specifying the required information are summarized below.
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Table 4-2 Description of the emission/control file
Record No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Variables
IDRUN
IDFILE
ISPTYP
IDDEP
IWDEP
DK(IC,1)
DK(IC,2)
DK(IC,3)
DK(IC,4)
DK(IC,5)
DK(IC,6)
DK(IC,7)
DK(IC,8)
IFIPS
IDSRC
UTMX
UTMY
ITYPE
IURB
INWS
NOSC(6)
NOWS(6)
NOWD(6)
RAD (12)
IDSTK
RLON
RLAT
STAKE
STAKE)
STAKV
START
IVENT
IBLDG
BLDW
BLDH
SAROAD
IDCAT
Q
Format
A40
A20
11
11
11
6F10
6F10
6F10
6F10
6F10
6F10
6F10
6F10
15
A10
F10
F10
11
11
15
611
611
611
12F5
A5
F10
F10
F10
F10
F10
F10
11
11
F10
F10
15
11
8F10
Description
Run identification
Emission file identifier
Species type (0 = gas; 1 = fine part.; 2 = coarse part.)
= 0, include dry deposition; = 1 no dry deposition
= 0, include wet deposition; = 1, no wet deposition
Decay rates for 6 stability classes for time block 1
Decay rates for 6 stability classes for time block 2
Decay rates for 6 stability classes for time block 3
Decay rates for 6 stability classes for time block 4
Decay rates for 6 stability classes for time block 5
Decay rates for 6 stability classes for time block 6
Decay rates for 6 stability classes for time block 7
Decay rates for 6 stability classes for time block 8
State/County FIPS code
Plant ID for points; census tract no. for pseudo points
Longitude (decimal degrees)
Latitude (decimal degrees)
Source type (0 or blank for points; 3 = pseudo points)
Urban/Rural flag (1 = urban; 2 = rural)
Star station (NWS) ID (blank or 0 = use nearest station)
Excluded stability classes
Excluded wind speeds
Excluded wind direction
Polar grid radial distances (km) (blank - use defaults)
Stack ID for points; FIPS code for pseudo points
Longitude (decimal degrees)
Latitude (decimal degrees)
Stack height (m)
Stack exit diameter (m)
Stack exit velocity (m/sec)
Stack exit temperature (Deg K)
Vent/Stack flag (0 = stacked; 1 = non-stacked)
Build flag (0 = no building; 1 = building)
Width of nearby building (m)
Height of nearby building (m)
5-digit Saroad code
1 -digit source category code
Emissions (g/sec) for eight 3-hour time blocks
Note that ASPEN treats the SAROAD code/source category code as
a single combined code to refer to a unique chemical and is
therefore technically not separable.
Notes: UTMX/UTMY and RLON/RLAT specify the locations of point sources, or the locations of the
census tract centroid for pseudo point sources (i.e., area and mobile sources).
Record 14 is repeated for each HAP emitted from the stack or census tract; terminate with blank record.
Records 13 and 14 are repeated for each source/stack within facility; terminate with blank record. (Last
stack and chemical for each facility will be followed by two blank lines to signal new facility.)
Records 10 through 14 are repeated for each facility or census tract, terminate with blank record. (Last
facility, stack and chemical in file will be followed by three blank lines to signal no more
facilities.)
Four blank records are required at the end of file to signal the end of the run.
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Syntax: IDRUN, IDFILE, ISPTYP, IDDEP, IWDEP
Type: Mandatory
Order: 1st record of emission/control input file
IDRUN and IDFILE are the character variables in the header which allow the user to specify the
title and the run information. ISPTYP is the species type: 0 for gaseous, 1 for fine
particulate and 2 for coarse particulate. IDDEP and IWDEP are the selections for dry and wet
deposition: 0 is the code to include deposition and 1 is the code to exclude deposition. Note that
for the gaseous pollutant species type, ASPENA will not calculate deposition, regardless of how
the deposition selection variables are set.
4.2.1.2 Reactive Decay Rate Inputs
The reactive decay rates are specified in the emission/control input file by stability class and time
block. ASPENA requires that all the HAPs included in a single emission/control input file have
the same decay rates. Therefore, a unique emission/control file is required for each set of HAPs
with different decay rates. The decay rates are specified in the emission/control input file for
each stability class and time block according to the following pattern: decay rates for time block
1 are entered in the second record, for time block 2 in the third record, and so on. The decay rate
for the last time block, time block 8, is entered in the ninth record of the emission input. The
syntax, type, and order for specifying reactive decay rates are summarized below. The reactivity
classes and corresponding decay rates normally used are presented in Appendix C.
Syntax: DK(IC,IH)
Type: Mandatory
- 9th record of emission/control input file
Order: 2nd
4.2.1.3 Source Types and Locations
ASPENA currently handles two source types, identified as point sources and pseudo point
sources. Area and mobile sources are treated as pseudo point source. The location of a source is
indicated by specifying the geodetic coordinates in latitude and longitude. The syntax, type, and
order for identifying source types and locations are as follows.
Syntax: IFIPS, IDSRCE, UTMX, UTMY, ITYPE, IURB
Type: Mandatory, Repeatable
Order: 10th record of emission/control input file
IFIPS is the FIPS code. IDSRCE is the plant ID for a point source, and census tract FIPS code
for pseudo point source. UTMX and UTMY are either the longitude and latitude of a point
source, or the census tract centroid in the case of a pseudo point source. ITYPE is source type: 0
or blank for point source, and 3 for pseudo point source. IURB is urban/rural designation: 1 for
urban and 2 for rural.
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The source locations are also specified along with source parameters in record 13 of the emission
input described in the next section.
Line 11 can be left blank. In this case, the closest meteorological station will be used by
latitude/longitude. Line 12 can be left blank. In this case default receptor grid will be used
4.2.1.4 Source Release Parameters
The input source parameters vary depending on the source type. For a point source, the stack
height, stack exit diameter, stack gas exit temperature, and stack gas exit velocity are required.
For a pseudo point source, no source parameters are required and ASPENA will use a default
stack height. The syntax, type, and order for specifying source release parameters are
summarized below.
Syntax: IDSTK, RLON, RLAT, STAKH, STAKD, STAKV, STAKT,
IVENT, IBLDG, BLOW, BLDH
Type: Mandatory/Optional, Repeatable
Order: 13th record of emission/control input file
IDSTK is the stack ID for point source, and census tract FIPS code for pseudo point source.
RLON and RLAT are either the longitude and latitude of a point source or the location of the
census tract centroid, in the case of a pseudo point source. STAKH is the stack release height
above ground (in meters). STAKD is the inside stack diameter (in meters). STAKV is stack gas
exit velocity (in m/sec). STAKT is the stack gas exit temperature (in degrees K). IVENT is the
vent/stack designation: 0 for stacked and 1 for non-stacked. IBLDG is the building flag: 1 to
include consideration of building downwash, 0 otherwise. BLOW and BLDH are the width and
height of nearby buildings (in meters).
4.2.1.5 Emission Rates
The emission rates are specified in ASPENA in eight 3-hour time blocks. The syntax, type and
order for specifying emission rates are summarized below.
Syntax: SAROAD, IDCAT, Q
Type: Mandatory, Repeatable
Order: 14th record of emission/control input file
IDCHEM is the 5-digit HAP SAROAD code plus 1-digit source category code. Q is the source
emission rates (in grams/second).
Multiple sources can be repeated as shown in the example in Section 8 (tutorial). In this case
lines 13 and 14 are repeated for each source/stack within facility.
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4.2.1.6 Secondary Compounds
ASPENA models atmospheric transformation processes as first-order reactive decay. Secondary
formation is calculated as the difference between secondary precursor concentrations with and
without reactive decay. This calculation is completed in the post-processing program
SEC_DAT. For a detailed description of the treatment of secondary HAPs see Section 6.1.
4.2.1.7 Deposition Rates
For particles, dry deposition rates are primarily a function of the particle size and land-use type.
The fine and coarse particle deposition velocities used in ASPENA were obtained for urban and
rural land-use types using the dry deposition algorithms in the Variable-grid Urban Airshed
Model (UAM-V) photochemical model (SAI, 1995). These values were further parameterized as
function of stability class and wind speed.
The ASPENA dispersion module uses the wet deposition algorithm from the revised version of
the CAP88-PC model to estimate the wet deposition of particles. The algorithms are based on
the approximate method described by Rodhe (1980) and use the fraction of time during which
precipitation is occurring in conjunction with the total annual precipitation to calculate both the
decay rate for the modeled ambient concentrations as well as the deposition fluxes.
4.2.2 STAR Meteorological Data File
ASPENA utilizes a climatological modeling approach. As with other climatological models
(e.g., the EPA's CDM and ISCLT), the dispersion module is supplied with STability Array
(STAR) meteorological data. STAR data include the joint frequencies of 6 wind speeds, 16 wind
directions and 6 stability categories (Pasquill - Gifford: A through F).
For each ASPENA model run, the STAR data is prepared for eight 3-hour time blocks for each
surface station. The station number and time block number are specified at beginning of each
STAR data record. The STAR input file is in binary format. Each record contains the STAR
data for one time block of one star station, and includes the variables shown in Table 4-3.
The STAR data is prepared as follows:
Split the surface data into eight 3-hour time blocks
• Generate STAR data for each time block
Combine the eight STAR data sets into one file
The format of the star data is provided in detail in Appendix C.
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Table 4-3 Description of the STAR meteorological data file
Variables
IWB
IHR
FSTAR
Data Type
Integer
Integer
Real
Description
Star (NWS) station ID
Time block number
STAR data for the time block
4.2.3 Meteorological Index File
The STAR data file is paired with a binary meteorological index file. The number and ordering
of stations included in both the index file and the STAR data file must be the same. There is one
record for each STAR station containing the following information: station number, station
longitude, station latitude, annual average daily maximum temperature, annual average daily
minimum temperature, annual average temperature, annual average precipitation, annual
frequency of precipitation, and annual average mixing heights for each of eight 3-hour blocks. A
description of the meteorological index file parameters is provided in Table 4-4.
Table 4-4 Description of the meteorological index file
Variables
ISTA
STAX
STAY
ATEMP (1)
ATEMP (2)
ATEMP (3)
PS
FPS
STAS
HTMI
Data Type
Integer
Real
Real
Real
Real
Real
Real
Real
Real
Real
Description
Star (NWS) station ID
Longitude of the station (decimal degree)
Latitude of the station (decimal degree)
Annual average daily maximum temperature (Deg K)
Annual average daily minimum temperature (Deg K)
Annual average temperature (Deg K)
Annual average precipitation (cm)
Fraction of time with precipitation
Not used (eight zeros)
Annual average mixing heights for eight 3 -hour time blocks
4.2.3.1 Temperatures
For each surface meteorological station included in the STAR data, the annual average daily
minimum, maximum and average temperature (in degrees Kelvin) is specified in the
meteorological index file.
4.2.3.2 Mixing Heights
For each surface meteorological station included in the STAR data, annual average mixing
heights (in meters) are specified for each of eight 3-hour time blocks in the meteorological index
file.
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4.2.3.3 Precipitation
For each surface meteorological station included in the STAR data, annual average precipitation
(cm/year) and fraction of time that precipitation occurs (based on hourly values) are specified in
the meteorological index file.
4.2.4 Polar Receptor Grid Network
Surrounding each modeled source, ASPENA uses a default polar receptor grid of 12 concentric
rings in 16 radial directions for a total of 192 receptors. The ring distances from each modeled
source are 0.1, 0.5, 1.0, 2.0, 5.0, 10.0, 15.0, 20.0, 25.0 30.0, 40.0, and 50.0 km.
Instead using the default concentric distances, the user can specify the distances for the 12 rings
between 100 meters and 50 km surrounding the modeled source.
4.3 ASPENA OUTPUTS
ASPENA creates two output files when it is executed. The first of these is the normalized source
concentration/deposition data file. This binary file contains the source information and the
normalized concentration/deposition for each of eight 3-hour time block at each receptor location
around the source, and the emission rates for each HAP. This file is used as input to the
ASPENB mapping module. The utility program INV2ASCI_CON can be used to convert the
ASPENA output from binary to ASCII format. Converting the file to ASCII allows the user to
review the modeling results of the ASPEN dispersion module. The utility does not convert the
deposition portion of the output, however. Note that a single binary output file is created which
will contain data for all sources and all HAPs specified in the emission/control input file.
The second file created by ASPENA is a listing of all emission sources (source FIPS, ID,
location, type and urban/rural destination) that were processed in the run. This file ends with a
line of zeros. The number of non-zero lines included in the file should equal the total number of
sources included in the emission/control file. This processed source listing file is written to
Fortran unit 88.
The user has the option of creating a third output file that echoes all the information included in
the meteorological index file, the emission/control file and the concentration/deposition output
file. This large file is typically used in the testing stage of the modeling study.
Once ASPENA has been run a log file with a ".como" extension is created. The log file includes
useful information including the input/output filenames and error messages. Table 4-5 presents a
summary of error messages in ASPENA.
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Table 4-5 Error messages in the ASPENA log file
Error Message
Too many chemicals
Comment: Max number of species is 150
Too many star stations
Comment: Max number of stations is 500
Bad number in star data
Comment: Errors in star index file
Can not find star data for station
Comment: Missing star data for stations
specified in the emission/control file
WARNING: iNWS, istar
Comment: The star station IDs specified in
the star data and index file are not in sync
Illegal urban/rural flag
Comment: urban/rural flag must be 1 or 2
Illegal source type
Comment: Source type must be 0 or 3
Error . . . idummy
Comment:
Module
ASPENA
ASPENA
ASPENA
ASPENA
ASPENA
ASPENA
ASPENA
ASPENA
Subroutine
SKIP
STACK
STARIN
STARIN
STAR
STAR
MAIN
MAIN
SKIP
Program Aborts
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
4.4 RUNNING ASPENA
ASPENA can be run interactively by simply typing:
aspena aspena.sys
where "aspena.sys" is the run stream filename.
Figures 4-2 and 4-3 show example run stream files used to run ASPENA. The first record in the
file contains the name of the emission/control file, the third record contains the name of the
meteorological index file, the fourth record contains the name of the STAR meteorological data
file, and the fifth record contains the name of the normalized source concentration/deposition
output file. The second record in the file is a placeholder for those that want to create the
optional "echo" output file described above. The creation of the testing file is invoked by
including a file name in record 2, as shown in Figure 4-2. To prevent the creation of the testing
file, "/dev/null" is entered in record 2, as shown in Figure 4-3.
1 aspena.ar.inp
2 aspena.ar.test
3 wtpmix.ind
4 star.dat
5 aspena.ar.con
Figure 4-2. Example ASPENA run stream file (filename: aspena.sys) that creates a testing file.
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1 aspena.ar.inp
2 /dev/null
3 wtpmix.ind
4 star.dat
5 aspena.ar.con
Figure 4-3 Example ASPENA run stream file (filename: aspena.sys) that does not create a testing file.
A job file can be created to run ASPENA multiple times, in sequence, as shown in the
Figure 4-4. For this example, ASPENA is run 3 times, using 3 different run stream files. The
two statements preceding each run line delete any previously created versions of the ASPENA
output files that will be created by the simulation. The statement after each run line renames the
processed source listing file, so that it will not be overwritten during the subsequent simulation.
rm aspena.tri.1st
rm aspena.tri.con
/bin/time aspena aspena.tri.sys
mv fort.88 aspena.tri.1st
#
rm aspena.ar.1st
rm aspena.ar.con
/bin/time aspena aspena.ar.sys
mv fort.88 aspena.ar.1st
#
rm aspena.mv.1st
rm aspena.mv.con
/bin/time aspena aspena.mv.sys
mv fort.88 aspena.mv.1st
Figure 4-4 Example ASPENA job file
In the above examples, the files with a "*.inp" extension contain the emission/control
information specifying the particular emission source for processing. In general, all chemicals of
the same species type (gas, fine, or coarse particles) with the same reactive decay rates and
deposition options may be processed in a single run, regardless of the source type or location.
4-13
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5.0 ASPENB USER'S INSTRUCTIONS
ASPENB is the mapping module of the ASPEN modeling system. ASPENB takes the diurnally-
stratified annual average concentration estimates from ASPENA and interpolates the results from
grid receptors to census tract centroids. Further, the contributions from all modeled sources are
summed to give estimates of cumulative ambient concentration increments in each census tract.
An overview of the inputs and outputs of the ASPENB module is shown in Figure 5-1.
Output from ASPENB is post-processed using a series of programs described in detail in
Section 6. By accounting for all identified source categories (including background
concentrations where available), the sum of the concentration increments should yield an
estimate of the overall concentration of each HAP within each census tract. These estimates are
designed to represent population-weighted concentration averages for each census tract.
'Census
Tract Index
Normalized HAPs
concentration/
deposition file
(ASPEN A output)
Census
Tract Data
I3rocessed source
concentration file
listing
Concentration/
deposition by
source category
and census tract
Figure 5-1 Flow diagram of the ASPENB mapping module
Several new features have been added to ASPENB (version 1.1). The detailed discussions of
these new features, along with the comparisons to the previous version are as follows:
• Number of output files produced by the model
Each output file produced from version 1.0 of the model contains the tract level
concentration/deposition for a single source category for a particular HAP. If there are ten source
categories for the HAP, there will be ten output files generated by the model. In version 1.1 of
the model there is a single output file or each HAP which contains the tract level
5-1
-------
concentration/deposition for all source categories. Therefore, the number of output files
produced by the model is greatly reduced.
• Output file naming convention
The naming convention for the output file generated by version 1.0 of ASPENB is 5-digit
SAROAD code plus a 1-digit source category code, with a "*.exp" extension. The naming
convention for the version 1.1 of ASPENB output file is simply the 5-digit SAROAD code with
a "*.exp" extension, i.e., the extra digit to identify the source category has been eliminated.
• Number of source categories contained in the ASPENB output file
Flexibility in the number of source categories, which can be included in a modeling simulation,
has been added to the version 1.1 of the ASPENB. The user selects the desired number of source
categories to be included in a particular modeling simulation. A maximum often source
categories is allowed.
• Rerun for a single source category
Each output file generated by version 1.0 of the model contains the tract level
concentration/deposition for a single source category for a particular HAP. If there is a need for
rerunning the simulation for that source category, the user can simply delete the output file
generated by the previous simulation, then rerun the model.
The output file generated by version 1.1 of the model contains the tract level
concentration/deposition estimates for all the source categories included in the modeling study.
If revision is needed for a single source category, that source category alone can be rerun and the
model will replace the previous estimates for that category in the output file. This feature avoids
a requirement to rerun all source categories (i.e., start the output file from scratch) in order to
revise a single source category.
5.1 ASPENB INPUTS
The ASPENB module requires three input files: the normalized concentration/deposition output
file from ASPENA, a census tract data file and a census tract index file. The input data
requirements are the same for both versions of ASPENB. A description of the input and output
files of the ASPENB module are provided in Table 5-1.
5-2
-------
Table 5-1 ASPENB input and output file descriptions
File Name
Normalized source
concentration and
deposition file
Census tract data
Census tract index
Population
concentration and
deposition file
(naming convention
(saroad}.EXP)
File listing
File
Type
Binary
Binary
Binary
Direct
access
binary
ASCII
Description
ASPENB input file
(ASPENA output
file)
ASPENB input file
ASPENB input file
ASPENB output
file
(AVGDAT input
file)
ASPENB output
file
Data Contents
Normalized concentration/deposition
estimates for the polar grid receptors
surrounding each emission source for
each of eight 3-hour blocks; emission
rates of the associated HAPs from
each source for each of eight 3 -hour
time blocks
Tract FIPS code, longitude and
latitude of the centroid, urban/rural
flag of the tract, and hypothetical tract
radius
State/county FIPS codes; state/county
max and min longitude/latitude;
pointer to the first county in state and
number of counties in state; pointer to
the first tract in county and number of
tracts in county
Estimates of annual average
concentrations (in |ig/m3) at each
census tract for each of eight 3 -hour
time blocks, and annual average
deposition fluxes over land and water
(in |ig/m2-day) for each HAP/source
category combination
List of processed concentration
filenames by ASPENB to prevent
processing an input more than once
5.1.1 Source Concentration and Deposition File
The first input required by the ASPENB module is the normalized source concentration/
deposition data output file from ASPENA. This binary file contains the source information and
the normalized concentration/deposition for each of eight 3-hour time block at each receptor
location around the source, and the emission rates for each HAP. See Appendix C for further
details.
5-3
-------
5.1.2 Census Tract Data File
The second input required by ASPENB is the binary census tract data file. The format of this file
is shown in Table 5-2. For each census tract, the tract data file contains the following:
State/County FIPS code and tract FIPS code
• Location of census tract centroid in longitude and latitude
Urban/rural designation
• Hypothetical tract radius
Table 5-2 Description of census tract data file
Variables
TRFIPS
TRLON
TRLAT
UFLAG
TRRAD
Data
Type
Integer
Real
Real
Integer
Real
Description
State/County FIPS code, tract FIPS code
Longitude of the tract centroid (decimal degree)
Latitude of the tract centroid (decimal degree)
Urban/Rural flag of the tract (1 = urban; 2 = rural)
Hypothetical tract radius (m)
The data in the census file are derived from the 1990 US Census. The longitude and latitude
represent an approximate population weighted census tract centroid. They are calculated as a
population-weighted average of the US Census reported geographic centroids of the constituent
block groups.
The urban/rural designation was specified based on residential population density: urban if
greater than 750 people/km2.
Finally, the hypothetical tract radius was derived from the tract area reported in the US Census,
under the assumption of a perfectly round shape:
TRRAD =
5.1.3 Census Tract Index File
The final input required by ASPENB is the binary census tract index file, containing the state and
county index data. The format of this file is shown in Table 5-3. The state index data are listed
with the following information for each state:
State FIPS code
• Maximum and minimum longitude and latitude of the state
Total number of counties in the state
5-4
-------
• Pointer to the first county of the state, i.e., the record number of the first county of that
state in the list of all counties (to follow in the tract index file)
The county index data are listed in the tract index file with includes the following information for
each county:
County FIPS code
Maximum and minimum longitude and latitude of the county
• Total number of tracts in the state
Pointer to the first tract of the state, i.e., the record number of the first tract of that county
in the list of all tracts (in the tract data file)
A utility program, MKTRACTS, generates the census index file utilizing ASCII formatted
census data. Figure 5-2 presents an example MKTRACTS job file.
Table 5-3 Description of census tract index file
Record No.
1
2
O
Variables
NSTATES
NCOUNTIES
NTRACTS
STFIP
STMNLN
STMNLT
STMXLN
STMXLT
COPTR
NUMCO
COFIPS
COMNLN
COMNLT
COMXLN
COMXLT
TRPTR
NUMTR
Data Type
Integer
Integer
Integer
Integer
Real
Real
Real
Real
Integer
Integer
Integer
Real
Real
Real
Real
Integer
Integer
Description
Total number of states included in the data
Total number of counties included in the
data
Total number of tracts included in the data
State FIPS code
State minimum longitude (decimal degree)
State minimum latitude (decimal degree)
State maximum longitude (decimal degree)
State maximum latitude (decimal degree)
Pointer to the first county in the state
Total number of counties in the state
County FIPS code
County minimum longitude (decimal
degree)
County minimum latitude (decimal degree)
County maximum longitude (decimal
degree)
County maximum latitude (decimal
degree)
Pointer to the first tract in the county
Total number of tracts in the county
Record 2 is repeated for all states included in
Record 3 is repeated for all counties included
the census tract data file.
in the census tracts data file.
5-5
-------
/bin/time src/mktracts « -eof-
DATA FILE |smptracts
-eof-
Figure 5-2 Example MKTRACTS job file
In the above example, the user input the ASCII formatted census tract data SMPTRACTS.ASC,
the utility MKTRACTS generates the corresponding binary formatted census tract data
(SMPTRACTS.DAT) and index file (SMPTRACTS.IND) required by ASPENB.
Figure 5-3 presents an example of ASCII formatted census tract data. Each record contains the
following variables: state FIPS, county FIPS, tract FIPS, longitude, latitude, tract hypothetical
radius, and urban/rural flag.
9
9
9
9
9
361
1
1
1
1
1
19
10101
10102
10201
10202
10300
15000
-73
-73
-73
-73
-73
-73
679499
633778
623645
588872
637447
617674
41
41
41
41
41
41
068223
097472
059098
063468
036887
334870
3
3
1
1
1
4
26
31
91
75
75
34
2
2
2
2
2
2
Figure 5-3 Example of ASCII formatted census tract data
5.2 ASPENB OUTPUTS
ASPENB creates two output files when it is executed. The first is the population
concentration/deposition file. This is the binary output file which contains estimated outdoor
concentrations (|ig/m3) and deposition fluxes (|ig/m2-day) for each HAP by census tract for each
of eight 3-hour time blocks. The utility EXP2ASCI converts the ASPENB output from binary to
ASCII format. This allows the user to easily view the modeling results of ASPENB. The format
of the binary and ASCII output files are provided in Appendix C.
The second file created by ASPENB is the processed source concentration file. This file contains
a list of all of the normalized source concentration/deposition input file names that have been
processed. This is used to avoid running the same input file twice.
5.3 RUNNING ASPENB
Figure 5-4 shows an example run stream file for ASPENB. As discussed above, there are three
required input files for the ASPENB: the normalized source concentration/deposition file
(output from ASPENA), the census tract data file, and the census tract index file. ASPENB
requires that the tract data and index files be located in the same directory where the job is run.
5-6
-------
Note that the tract data and index files are specified in record 2 of the run stream file by their
base name only (do not include any extensions). In the directory in which they reside, the two
files should be distinguished by the following extensions: tract data file (*.dat) and index file
(*.ind).
/bin/time aspenb « -ieof-
ONROAD MV FILE
TRACT FILE BASENAME
FILE LIST FILENAME
NO. OF SRC CATEGORY
RERUN (Yes/No)
-ieof-
cats.con
tracts
filelist.ntl
No
Figure 5-4 Example ASPENB run stream file
The run stream file shown in Figure 5-4 is set up for a modeling simulation that includes total
number of five source categories, and it is not a rerun. Important parameters for the run stream
are as follows:
Filename for input normalized source concentration/deposition file: catS.con
• Base name of the census tract data file and index file: tracts
• Filename for output file listing: filelist.ntl
• Number of source categories included in the modeling: 5
Status of the run, i.e., if it is a rerun: NO
A separate population concentration/deposition output file is created by ASPENB for each HAP.
The naming convention for the output file is 5-digit SAROAD code with a "*.exp" extension.
For example, the output file for toluene (with SAROAD code 45202) will be named as
45202.exp. Each time a HAP is encountered during the ASPENB simulation, the local directory
is checked to determine whether an appropriate HAP output file already exists. If not, one is
created. If so, the previous values for the current source category are incremented by the current
estimates to obtain cumulative concentration and deposition estimates for each census tract for
that source category.
In the example shown in Figure 5-4, if the emissions data for the CATS are revised, ASPENA
can be rerun for that category to produce revised normalized source concentration/deposition
data. A remodeling for the category can be completed using the rerun feature of ASPENB,
without having to rerun the simulations for other source categories. Figure 5-5 presents the
ASPENB run stream file using the rerun feature. Note that the only difference between the run
stream shown in Figure 5-4 and 5-5 is the selection for the status of the run.
5-7
-------
/bin/time aspenb « -ieof-
ONROAD MV FILE
TRACT FILE BASENAME
FILE LIST FILENAME
NO. OF SRC CATEGORY
RERUN (Yes/No)
-ieof-
cat3.rev.con
tracts
filelist.ntl
Yes
Figure 5-5 Example ASPENB run stream file using the rerun feature
To successfully execute a rerun for a particular source category, special attention should be paid
to the following:
• Specify "Yes" for rerun status in the ASPENB run stream file
• Use the revised ASPENA output file (as shown in the example cat3.rev.con) as one of the
input files
• Provide the ASPENB output files from the previous modeling runs. Those files contain
results from the previous modeling for all source categories, and the rerun will modify the
results for the single category specified in the input normalized concentration file
• If the normalized concentrations file name remains unchanged in the rerun from the
previous modeling run (i.e., if catS.con is the normalized concentrations file name used in
both runs in the examples shown above), then the file name should be removed from
filelist.ntl generated in the previous run, because the model will not allow running a file
with a name included in filelist.ntl.
Once ASPENB has been run a log file with a ".como" extension is created. The log file includes
useful information including the input/output filenames and errors. Table 5-4 presents a
summary of error messages in ASPEN. At the end of a run, the log file displays the following
message: "All done: X sources processed," where X is the total number of emission sources in
the simulation. The number and type of sources processed by ASPENB should be the same as
those processed in the corresponding ASPENA simulation.
Table 5-4 Error messages in the ASPENB log file
Error Message
Error reading source file
Comment: read error or unexpected of in
normalized concentration/deposition file
Module
ASPENB
Subroutine
NEXTSOURCE
Program
Aborts
Yes
5-8
-------
5.4 MODEL RE-START CAPABILITY
ASPENA has no direct re-start capability. However, it is possible to re-start ASPENB indirectly
in some cases. For example, for large modeling domains ASPEN input files for the same
HAP/source category combinations may be divided into several files (e.g., stratified by
geographic region). When ASPENB processes the first ASPENA output file, it creates the
appropriate ASPENB HAP output files. When subsequent ASPENA output files are processed
by ASPENB, the previously created ASPENB HAP output files are incremented to accumulate
the concentration increments from all sources for that HAP/source category combination.
To avoid losing output data in the event of ASPENB aborting while processing one of the
multiple files, the user can make an intermediate copy of the ASPENB output files at the
completion of the processing of each ASPENA output file. (See Figure 5-6 for an example job
file.) Then if a run aborts, ASPENB can be re-started at the beginning of the aborted simulation,
using the intermediate ASPENB output files as the starting point. Figure 5-7 presents an
example job file for re-starting the job specified in the Figure 5-6 job file, if it were to abort
during the second ASPENB simulation. First, the partially updated output files are deleted.
Then the intermediate files are copied back into the local directory. Finally the ASPENB job is
re-started at the beginning of the simulation that aborted. Note that this procedure requires
knowledge of the HAPs that will be processed so that the names of the ASPENB output files are
known.
/bin/time aspenb « -eof-
ON ROAD MV FILE |cats.epal.con
TRACT FILE BASENAMEjtracts
FILE LIST FILENAME jfilelist.ntl
NO. SOURCE CATEGORY j 5
RERUN(YES/NO) jNO
-eof -
#
cp -p 45202.exp tmp/45202.exp
cp -p filelist.ntl tmp/filelist.ntl
#
/bin/time aspenb « -eof-
ON ROAD MV FILE |cat3.epa2.con
TRACT FILE BASENAME j tracts
FILE LIST FILENAME jfilelist.ntl
NO. SOURCE CATEGORY j5
RERUN (YES/NO) jNO
-eof -
Figure 5-6 Example ASPENB job file that creates intermediate output files
5-9
-------
rm 45202.exp
rm filelist.ntl
cp -p tmp/45202.exp 452023.exp
cp -p tmp/filelist.ntl filelist.ntl
/bin/time aspenb « -eof-
ON ROAD MV FILE |cat3.epa2.con
TRACT FILE BASENAME jtracts
FILE LIST FILENAME jfilelist.nt
NO. SOURCE CATEGOEY j5
RERUN (YES/NO) jNO
-eof-
Figure 5-7 Example of an ASPENB re-start job file
5-10
-------
6.0 POST-PROCESSING MODEL OUTPUTS
A series of software programs are used to post-process the ASPENB model output. A detailed
descriptions of the post-processors are presented in this section.
There are three post-processors for ASPENB, they are:
AVGDAT
EXTRDAT
SECDAT
calculates the annual average HAP concentration for each source
category included in the ASPENB output, calculates the total
annual average concentrations over all categories including the
background value provided by the user
converts the concentration data files from binary to ASCII format
generates the secondary pollutant concentrations and combines the
concentrations of the primary and secondary components
Note that the processing procedures, which were carried out by two post-processors in version
1.0 of the model (MRG_DAT and BACKGRND), have been incorporated into the post-processor
AVGDAT. Therefore, those two processors are no longer needed for version 1.1 of the model.
Figure 6-1 presents a flow chart of the relationships among the post-processors.
yes
Population
concentration/deposition
by source category by
census tract (ASPEN B
output)
Secondary HAP
formation?
'
DAT
no
\
i
AVGDAT
Census Data
Annual Average HAP
Concentration by
Census Tract
Figure 6-1 Flow chart of the ASPEN post-processors.
6-1
-------
6.1 GENERATING CONCENTRATIONS FOR THE SECONDARY COMPOUNDS
ASPEN estimates the concentration of the secondary HAPs as the difference between the
precursor concentration in an inert model run and its concentration in the presence of reactive
decay. The resulting concentration differences are adjusted for molar yield and molecular weight
to estimate the concentration of the secondary HAP.
The post-processor SECDAT is used for generating the concentration estimates of the secondary
HAPs, and combining the concentrations of the primary and secondary HAPs. The SECDAT
output file is in the same format as the population concentration/deposition file, so that it can be
further processed by AVGDAT. Figure 6-2 present an example job file for generating secondary
and total concentrations of acrolein.
The job file in Figure 6-2 is formatted as follows:
Number of source categories included in the ASPENB output file: 5
• Filename of census tract list: ustracts.lst
• SAROAD code for secondary arolein: 80265
• Output filename: 80265.exp
Scaling factor:-1.04
Note: the negative sign indicates that concentration differences of the HAPs specified
below should be calculated
• The inert concentration filename: 80302.exp (80302 is the SAROAD code for inert 1,3-
butadiene)
• The reactive concentration filename: 43218.exp (43218 is the SAROAD code for 1,3-
butadiene)
To generate the concentrations for the total acrolein, the job file is set up as follows:
Number of source categories included in the ASPENB output file: 5
• Filename of census tract list: ustracts.lst
SAROAD code of the total acrolein: 80266
• Output filename: 80266.exp
Scaling factor: 1.0
Note: the positive sign indicates to calculate the total concentration of the HAPs specified
below
• The primary acrolein concentration filename: 435051.exp (43505 is the SAROAD code
for acrolein)
• The secondary arolein concentration filename: 80265.exp
6-2
-------
#
# Generate secondary species for all source categories
#
rm aspenb/output/80265.exp
/bin/time src/secdat « ieof
5
data/ustracts.1st
80265
aspenb/output/80265.exp
-1.04
aspenb/output/80302.exp
aspenb/output/43218.exp
ieof
#
# Generate total for all categories
#
rm aspenb/output/80266.exp
/bin/time src/secdat « ieof
5
data/ustracts.1st
80266
aspenb/output/80266.exp
1.0
aspenb/output/43505.exp
aspenb/output/80265.exp
ieof
Figure 6-2 Example job file for the SECDAT post-processor
The difference between the post-processor SECDAT and its predecessor SEC_DAT is that the
new version greatly simplifies the processing procedure. In a single run SEC_DAT only treats
the processing for one source category for a particular HAP; but SECDAT can complete the
processing for all the source categories for the HAP included in the ASPENB output. The run
stream set up for SECDAT is the same as the one for SEC_DAT, except that total number of
source categories included in the ASPENB output file needed to be specified, and the file name
will be in the format of 5-digit SAROAD code with ".EXP" extension (i.e., the source category
code digit is no longer needed).
6.2 CALCULATING ANNUAL AVERAGE CONCENTRATION
The post-processor AVGDAT is used to convert the model results into annual average
concentrations. The input concentration are estimated for eight 3-hour time blocks; the post-
processor calculates the average for the time blocks. The post-processor reads in the
concentrations in eight 3-hour time blocks for all the source categories included in the population
concentration/deposition file. Then it calculates the annual average concentrations for each
source category and total annual average concentration over all source categories, including the
background value provided by the user.
6-3
-------
Figure 6-3 presents an example job file for calculating the average concentration of benzene.
Important parameters for this run stream are as follows:
The number of source categories included in the ASPENB output file: 5
• Filename for census tract list: ustracts.lst
Output filename: 45201.exp.avg
HAP SAROAD code: 45201 (benzene)
Path for input concentration file: aspen/
• Background value for the HAP in |ig/m3: 0.479
rm 45201.exp.avg
/bin/time avgdat « ieofa
5
ustracts.1st
45201.exp.avg
45202
aspen/
0.479
ieof
Figure 6-3 Example job file for the post-processor AVGDAT
Note that only the path is required for the input concentration files.
6.3 EXTRACT AND TABULATE ANNUAL AVERAGE CONCENTRATION
The output from AVGDAT is in binary format. The EXTRDAT post-processor converts this file
from binary to ASCII format. The post-processor provides the following options to the user:
Select the concentration units: |ig/m3, ppm, pphm, ppb or ppt, input as MGPCM, PPM,
PPHM, PPB or PPT
Select census tracts:
To convert concentrations for all census tracts: input-1 (see Figure 6-4)
To extract concentrations for the listed tracts only: input total number of tracts, and list
the tracts of interest (see Figure 6-5)
Figure 6-4 presents an example job file for converting benzene concentrations from binary to
ASCII for all tracts (in |ig/m3). Important parameters in the job file include:
Number of source categories included in the ASPENB output: 5
• Name of input file: 45201.exp.avg
Name of output file: 45201 .exp.out
HAP SAROAD code: 45201 (benzene)
Filename for census tract list: ustracts.lst
6-4
-------
HAP name, desired measurement units, molecular weight: BENZENE, MGPCM, 78.11
(format: A10,A8,F10)
Indicator of census tract selection: -1 (all census tracts)
rm 45201.avg.out
/bin/time extravg « ieofa
5
45201.exp.avg
45201.avg.out
45201
ustracts.1st
BENZ MGPCM 78.11
-1
ieof
Figure 6-4 Example 1 job file for the EXTRDAT post-processor
Figure 6-5 presents an example run stream for converting benzene concentrations from binary to
ASCII for only the 10 listed tracts (units in ppb).
rm 45201 .avg. out
/bin/time extravg «
5
45201 . exp . avg
45201 .avg. out
45201
ieof
ustracts . 1st
BENZ
10
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
ieof
PPB
10101 -
10102 -
10201 -
10202 -
10300 -
10400 -
10500 -
10600 -
10700 -
10800 -
73
73
73
73
73
73
73
73
73
73
78.
67950
63378
62364
58887
63744
65913
64153
62646
61841
59914
11
41
41
41
41
41
41
41
41
41
41
06822
09747
05910
06347
03689
02311
01606
02859
02867
04003
Figure 6-5 Example 2 job file for the post-processor EXTRDAT
6-5
-------
7.0 COMPUTER NOTES
7.1 MINIMUM HARDWARE REQUIREMENTS
The computer resources required to run the ASPEN application are contingent upon the number
of emission sources and HAPs to be processed. The disk storage requirements to run a
simulation on a UNIX workstation (Sun Ultra Spare 2 / Solaris 2.5.1), using the emissions from
one source category (on-road mobile), one reactivity class (reactivity class 2 including emissions
from 11 HAPs) in a single EPA region (EPA region 9) is approximately 1.3 Mbytes for
ASPENA, and 2.7 Mbytes for ASPENB. It takes 6 CPU hours for both ASPENA and ASPENB
for this simulation. Table 7-1 presents the disk storage requirements.
Table 7-1 ASPEN disk storage requirements for example simulation.
File Disk Storage (Mbytes)
Inputs
Meteorological (214 stations) 4.0
Census tract (48 states, 60,803 tracts) 1.8
Emissions 8.4
Outputs
Normalized source concentration/deposition 4.2
(binary)
Population concentration/deposition (binary) 31.9 (2.9 Mbytes / HAP x 11
HAPs)
Annual average concentration (ASCII) 106.7 (9.7 Mbytes / HAP x 11
HAPs)
Total 157
7.2 COMPILING AND RUNNING ASPEN ON A UNIX WORKSTATION
The commands for compiling ASPEN on a UNIX workstation are presented in Figure 7-1 and
Figure 7-2.
7-1
-------
FLGS = -02
TARGT = aspena
OBJCTS = \
gauss.o \
gaussz.o \
header.o \
list.o \
notice.o \
opnfil.o \
point.o \
prise.o \
save.o \
aspena.o \
sigmaz.o \
stack.o \
star.o \
starin.o \
szcoef.o \
ddmpr.o \
vert.o \
depos.o \
biddisp.o \
vgausz.o \
blkmet.o \
blkdep.o \
skip.o
$(TARGT): $(OBJCTS)
f77 -O $(TARGT) $(FLGS) $(OBJCTS)
.f .0 :
f77 -C $(FLGS) $<
Figure 7-1 The commands for compiling ASPENA on a UNIX workstation
7-2
-------
FLGS = -02
TARGT = aspenb
OBJCTS = \
addSource.o \
areaAvgl.o \
areaAvg2.o \
aspenb.o \
findResTr.o \
findcloTr.o \
impacted.o \
initSearch.o \
initTarget.o \
inside.o \
interpolate.o \
loadTracts.o \
nextCo.o \
nextSource.o \
nextSt.o \
nextTarget.o \
nextTr.o \
openSource.o \
ptAverage.o \
receploc.o \
setPts.o \
tolog.o \
update.o
$(TARGT): $(OBJCTS)
f77 -o $(TARGT) $(FLGS) $(OBJCTS)
.f .0 :
f77 -c $(FLGS) $<
Figure 7-2 The commands for compiling the ASPENB on a UNIX workstation.
7.2.1 Modifying the Array Limits
In the current version of ASPEN, the array limits are configured as follows:
• Maximum number of meteorological station: 500
• Maximum number of pollutants: 150
• Maximum number of radial distances of the grid: 12 (in ASPENA)
• Maximum number of azimuth direction of the grid: 16
• Maximum number of time blocks: 8
• Maximum number of HAPs emits from a source: 100
• Maximum number of census tracts: 60,803
Maximum number of the states included in the tracts data: 49
7-3
-------
• Maximum number of counties included in the tracts data: 3,111
• Maximum number of the tracts included in a county: 2,000
• Maximum number of the fields included in the population concentration/population file:
12. The 12 fields are: State/County FIPS code, tract FIPS code, concentrations in eight
3-hour time blocks, deposition over the land and water
Most of the array limits are specified in PARAMETER statements. Exceptions, which are hard
coded, include the number of receptor grid radial distances (12), the number of receptor grid
azimuthal directions (16), and the number of time blocks (8) in the ASPENA module.
Depending on the amount of memory available on the particular computer system being used,
and the needs for a particular modeling application, the other array limits can be easily changed,
and the model can be recompiled.
If the user changes the number of time blocks in the ASPEN model, the ASPENA
emission/control input file, and the number of the fields included in the ASPEN output files
would also need to be changed.
7.3 PORTING THE MODEL TO THE OTHER HARDWARE ENVIRONMENTS
7.3.1 PC
The ASPEN models are designed and coded to allow them to run on most operating
environments, including UNIX and DOS. The current version of the model is written to run on
UNIX. Although the users do not need to make major changes, they may experience some minor
differences between UNIX to PC environments, including the following:
• The suffix .f of all source files should be changed to .for
• The subroutine OPNFIL of ASPENA uses GETARG to read input run stream filename,
which is compiler dependent. GETARG may be available under a different name for
another compiler.
7-4
-------
8.0 ASPEN MODEL TUTORIAL
This section presents examples of the setup and use of ASPEN. Several example applications
are provided to demonstrate how to set up a basic modeling scenario and post-process the model
output. A more detailed discussion of each module is provided in Sections 5, 6, 7 and
Appendix C. Two main example scenarios are presented in this section: a gaseous HAPs and a
particulate HAPs scenario. There are three examples provided for calculating annual average
concentrations for a single gaseous HAP. The final example is for calculating concentrations and
depositions for two particulate HAPs.
8.1 EXAMPLE 1 - GASEOUS HAPS
This example problem is to simulate gaseous toluene concentrations by census tract in one
county (Fairfield, CT). For this example, multiple emission sources (point, area, and on-road
mobile) are modeled. Users must prepare an emission/control input file for each source category.
A description of the input file parameters required for the emission/control input file for each
source category is provided. The reactivity for toluene for this example is assigned to category 4.
8.1.1 Setting up the Emission/Control Input File for Point Sources
For this example, the input file is prepared to simulate toluene concentrations from two point
sources. The point source emissions data used in this example are from the U.S. EPA's Toxic
Release Inventory (TRI) database. The emission/control input file for ASPENA is presented in
Figure 8-1.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
23
24
25
26
TRI Point Sources
9.870e
9.870e
1.180e
7.890e
6.710e
2.370e
1.970e
9.870e
09001
1 -73
452020
09001
1 -73
452020
-07 9.870e
-07 9.870e
-05 7.890e
-05 5.920e
-05 5.130e
-05 1.780e
-06 1.970e
-07 9.870e
16269
.2694 41
1.25e-01
16291
.4167 41
2 .62e-03
-07 9
-07 9
-06 3
-05 3
-05 3
-05 1
-06 1
-07 9
-73.
.1417
.870e
.870e
.950e
.950e
.550e
.1806
.970e
.870e
2694
1.256-01
-73 .
.3661
4167
2 .62e-03
-07
-07
-06
-05
-05
-05
-06
-07
9.870e-
9.870e-
1.970e-
1.970e-
1.9706-
7.890e-
9.870e-
9.870e-
07
07
06
05
05
06
07
07
Reactive Catagory
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
-07
-07
-07
-07
-07
-07
-07
-07
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
9.870e
4 Oil
-07
-07
-07
-07
-07
-07
-07
-07
41.141702
8.
1.
90
25e-01
0.
1.
67
25e-01
12 .
1.
00 323.0000 0.00 0.00
25e-01
1.256-01 1.256-01 1.256-01
41.366102
24 .
2 .
00
62e-03
0.
2 .
49
62e-03
20.
2 .
53 332.0000 0.00 0.00
62e-03
2.62e-03 2.62e-03 2.62e-03
Figure 8-1 Example emission/control input file for point sources (filename: "aspena.tri.inp")
8-1
-------
A record by-record description of the input file data requirements is as follows:
Line 1 (header): The run identifier (title), pollutant species type, and deposition
parameters are specified here. For this example, the parameters are set to: gaseous
species type (= 0); no dry deposition (=1), and no wet deposition (=1).
Lines 2-9: The decay rates of reactivity category 4 are specified for each of the six
stability classes (A-F) and eight 3-hour time blocks.
Lines 10-14: For each point source modeled, the source location, emissions, and various
stack parameters must be specified. Detailed information for the two TRI sources
included in this example is provided in Table 8-1. For a description of the input file
format for each of these variables, see Table C-l in Appendix C.
Lines 15-16: These lines are left blank to indicate the end of information for the emission
source.
Lines 17-21: This section contains data for a second point source, analogous to lines 10-
14.
Lines 22-26: These lines are left blank to indicate the end of the file.
Table 8-1 Point source data parameters entered into the emission/control input file
Variable
FIPS code
Plant ID
Longitude
Latitude
Source type
Urban/Rural flag
NWS station ID
Stack ID
Longitude
Latitude
Stack height (m)
Stack diameter (m)
Stack exit velocity (m/sec)
Stack exit temperature (Deg K)
Vent/Stack flag
Building flag
Width of nearby building (m)
Height of nearby building (m)
HAP Saroad code
Source category
Emissions of each time block
(g/sec)
Source No. 1
09001
16269
-73.2694
41.1417
0
2
Blank
1
-73.2694
41.1417
8.9
0.67
12.0
323.0
0
0
0.0
0.0
45202
0
0.125
Source No. 2
09001
16291
-73.4167
41.3661
0
2
Blank
1
-73.4167
41.3661
24.0
0.49
20.53
332.0
0
0
0.0
0.0
45202
0
2.62X10'3
Remarks
Fairfield, CT
Point source
Rural
Use nearest station
Stacked
No building
Toluene
TRI-Nonmetal
Flat temporal
profile
8-2
-------
8.1.2 Setting up the Emission/Control Input File for Mobile Sources
The example emission/control input file for mobile sources is presented in Figure 8-2.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
On-Road MV Sources
9.87E
9.
1.
7.
6.
2 .
1.
87E
18E
89E
71E
37E
97E
9.87E
-07
-07
-05
-05
-05
-05
-06
-07
09001
4781
09001 -
4520230
73.
9.87E
9.
7.
5.
5.
1.
1.
87E
89E
92E
13E
78E
97E
9.87E
30400 -
4919
.1482E+000
09001
4781
09001 -
4520230
73 .
30500 -
5024
.1168E+000
-07
-07
-06
-05
-05
-05
-06
-07
73.
41.
9.87E
9.87E
3 .95E
3.95E
3.55E
1.18E
1.97E
9.87E
4919
0644
.1482E+000
73.
41.
5024
0780
.1168E+000
-07
-07
-06
-05
-05
-05
-06
-07
41.
Reactive Category 4 Oil
9.87E-07 9.87E-07 9.87E-07
9.87E-07 9.87E-07 9.87E-07
1.97E-06 9.87E-07 9.87E-07
1.97E-05 9.87E-07 9.87E-07
1.97E-05 9.87E-07 9.87E-07
7.89E-06 9.87E-07 9.87E-07
9.87E-07 9.87E-07 9.87E-07
9.87E-07 9.87E-07 9.87E-07
0644 31
1
.1113E+010.9006E+000.9317E+000.1289E+010.5786E+000.1613E+00
41.
0780 31
1
.8744E+000.6927E+000.7138E+000.1005E+010.4522E+000.1257E+00
Figure 8-2 Example emission/control input file for on-road mobile sources (filename: "aspena.mv.inp")
Mobile source emissions are specified at the census tract level as pseudo point sources. This
example includes toluene emissions from on-road mobile sources for two census tracts (tracts
30400 and 30500).
• Lines 1-9: These records are identical to the point source emission/control input file
shows in Figure 8-2 (except for the run identifier) because both include emissions for
toluene.
• Lines 10-14: The format of these lines is the same as for the point source example
discussed above. However, some of the variables represent somewhat different
parameters for this case.
Line 10: The census tract FIPS code (30400) is used instead of the plant ID, and
the coordinates (longitude and latitude) of the census tract centroid is specified
instead of the plant location. On-road mobile sources are considered "pseudo
points", with a source category code of 3.
8-3
-------
Line 11: For this example the NWS station ID for the desired meteorological
station is specified. If left blank, as it was in the point source example, the closest
station in the data base would be assigned. However, for "pseudo points" the
meteorological stations are generally pre-determined so that sources can be
grouped according to meteorological station and urban/rural designation to save
computing time. This is discussed in Appendix C.
Line 13: The source type for mobile sources (and area sources) is designated as
non-stacked (vent/stack flag = 1), and pseudo point source (source type = 3).
Line 14: In contrast to the point source example, for this case the emission rate
varies among the eight time blocks.
• Lines 15-16: These lines are left blank to indicate the end of information for the emission
source.
• Lines 17-21: This section contains data for a second pseudo point source, analogous to
lines 10-14.
• Lines 22-26: These lines are left blank to indicate the end of the file.
8.1.3 Setting up the Emission/Control Input File for Area Sources
Like mobile sources, area sources are specified at the census tract level as pseudo point sources.
Figure 8-3 shows an emission/control input file for simulating toluene emissions from two area
sources in two census tracts (tract #s 35100 and 42700). The input file for area source emissions
is very similar to the mobile source file discussed in Section 8.1.2. The only difference is that
there are two emissions records in the area source file, corresponding to the two area source
categories: manufacturing emissions (source category code = 5), and non-manufacturing
emissions (source category code = 6). This can be seen in Figure 8-3, where the manufacturing
and non-manufacturing emissions in census tract 35100 are represented by records 14 and 15,
respectively.
8.1.4 Running ASPENA
The two types of input required to run ASPENA are the emission/control file, and the
meteorological files. Procedures for preparing the emission/control file are discussed in Sections
8.1.1-8.1.3. The meteorological data input requirements include STAR meteorological data
and a meteorological index file. Versions of the latter two files, containing national 1990 data,
are provided as part of the ASPENA modeling system.
8-4
-------
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Area Sources
9.87E
9.87E
1.18E
7.89E
6 . 71E
2.37E
1.97E
9.87E
09001
4781
09001 -
4520250
4520260
09001
4781
09001 -
4520250
4520260
-07 9.
-07 9.
-05 7.
-05 5.
-05 5.
-05 1.
-06 1.
-07 9.
87E
87E
89E
92E
13E
78E
97E
87E
35100 -
73 .4919
.OOOOE+
.1249E-
000
010
42700 -
73 .4209
.OOOOE+
000
.2810E+010
-07 9.
-07 9.
-06 3.
-05 3 .
-05 3 .
-05 1.
-06 1.
-07 9.
73 .4919
41.1433
.OOOOE+
.5239E-
73 .4209
41.1425
.OOOOE+
87E
87E
95E
95E
55E
18E
97E
87E
000
010
000
.5116E010.
-07 9.87E
-07 9.87E
-06 1.97E
-05 1.97E
-05 1.97E
-05 7.89E
-06 9.87E
-07 9.87E
41.1433 31
.1785E-010
.1336E+000
41.1425 31
.8033E010.
1549E+000.
Reactive Category
-07 9.87E
-07 9.87E
-06 9.87E
-05 9.87E
-05 9.87E
-06 9.87E
-07 9.87E
-07 9.87E
.5356E-010
.1529E+000
2410E+000.
2566E+000.
-07 9
-07 9
-07 9
-07 9
-07 9
-07 9
-07 9
-07 9
.5356E
.87E
.87E
.87E
.87E
.87E
.87E
.87E
.87E
-010
.1208E+000
2410E+
000.
2381E+000.
4 Oil
-07
-07
-07
-07
-07
-07
-07
-07
1
.5356E-010
.9346E-010
1
2410E+000.
2223E+000.
.5356E+010.5356E-01
.4291E-010.2793E-01
2410E+000.2410E+00
1437E+000.9328E-01
Figure 8-3 Example emission/control input file for area source (filename: "aspena.ar.inp")
Once the input files have been prepared and formatted according to the specifications provided in
Appendix C, run stream files need to be created that include the input and output filenames for
the simulation.
Example run stream files for area, point and mobile and gaseous HAPs simulations are shown in
Figures 8-4, 8-5, and 8-6. The filenames shown in the figures correspond to the following:
• aspena.xx.inp - emission/control input file (format: ASCII)
wtpmix.ind - meteorological index input file (format: binary)
• star.dat - STAR meteorological data file (format: direct access binary)
aspena.xx.con - ASPENA normalized source concentration/deposition output file
(format: binary)
where, "XX" refers to one of the following source category codes:
ar - area source
tri - point source
mv - mobile source
aspena.ar.inp
/dev/null
wtpmix.ind
star.dat
aspena.ar.con
Figure 8-4 Run stream file for the gaseous HAPs ASPENA run (filename: "aspena.ar.sys")
8-5
-------
aspena.tri.inp
/dev/null
wtpmix.ind
star.dat
aspena.tri.con
Figure 8-5 Run stream file for ASPENA point run (filename: "aspena.tri.sys")
aspena.mv.inp
/dev/null
wtpmix.ind
star.dat
aspena.mv.con
Figure 8-6 Run stream file for ASPENA mobile run (filename: "aspena.mv.sys")
In addition to the pollutant concentration output file, ASPENA also creates an output file with
listing all the emission sources processed in Fortran unit 88. It is convenient to rename this file
at the conclusion of each simulation, so that it will no be overwritten by the next simulation in
the job. Figure 8-7 presents an example of a job file for ASPENA simulations made with the
example files discussed above. In the example, the 3 processed source listing files produced for
the three simulations are renamed from "fort.88" to "aspena.tri.lst", "aspena.ar.lst", and
"aspena.mv.lst".
rm aspena.tri.lst
rm aspena.tri.con
/bin/time aspena aspena.tri.sys
mv fort.88 aspena.tri.lst
#
rm aspena.ar.lst
rm aspena.ar.con
/bin/time aspena aspena.ar.sys
mv fort.88 aspena.ar.lst
#
rm aspena.mv.lst
rm aspena.mv.con
/bin/time aspena aspena.mv.sys
mv fort.88 aspena.mv.lst
Figure 8-7 Example of ASPENA job file
-------
plant FIPS number: 9001
plant ID: 35100 stack type: 3 Long/Lat coordinates : -73.492 41.143 urban/rural l=urban; 2=rural
Species type : 0
ambient temperatures (k): 289.000 279.000 284.000
meteorological station: 4781
utm coordinates (km): -73.100 40.783
excluded stabilities: 000000
wind speeds: 000000
wind directions: 0000000000000000
Average Precip and freq : 110.2106 0.2067
Stack ID : 09001
Long/Lat coordinates : -73.492 41.143
stack height (m): 0.00
diameter (m): 0.00
exit velocity (m/s): 0.00
exit temperature (k): 0.00
vent/stack class: vent
Calculated concentrations for hour 1 from--
chemicals emitted: 452025 452026
emission rate (g/s): O.OOE+00 0.12E-01
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 5.0E+01 2.8E+00 8.4E-01 2.6E-01 6.0E-02 2.2E-02 1.2E-02 8.3E-03 6.1E-03 4.7E-03 3.2E-03 2.4E-03
22.5 3.8E+01 2.1E+00 6.3E-01 1.9E-01 4.5E-02 1.6E-02 9.4E-03 6.3E-03 4.7E-03 3.7E-03 2.5E-03 1.9E-03
Calculated concentrations for hour 8 from--
chemicals emitted: 452025 452026
emission rate (g/s): 0.54E-01 0.28E-01
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 6.0E+01 3.5E+00 l.OE+00 3.2E-01 7.4E-02 2.7E-02 1.5E-02 9.8E-03 7.1E-03 5.5E-03 3.7E-03 2.7E-03
22.5 4.7E+01 2.7E+00 7.9E-01 2.4E-01 5.7E-02 2.1E-02 1.2E-02 7.8E-03 5.7E-03 4.5E-03 3.0E-03 2.3E-03
No Deposition Calculations Specified on Input ..
Total Plants Processed : 2
Figure 8-8 ASPENA diagnostic file created by example area source run
8-7
-------
plant FIPS number: 9001
plant ID: 30400
stack type: 3
Long/Lat coordinates : -73.492 41.064
urban/rural l=urban; 2=rural : 1
Species type : 0
ambient temperatures (k): 289.000 279.000 284.000
meteorological station: 4781
utm coordinates (km): -73.100 40.783
excluded stabilities: 000000
wind speeds: 000000
wind directions: 0000000000000000
Average Precip and freq : 110.2106 0.2067
Stack ID : 09001
Long/Lat coordinates : -73.492 41.064
stack height (m): 0.00
diameter (m): 0.00
exit velocity (m/s): 0.00
exit temperature (k): 0.00
vent/stack class: vent
Calculated concentrations for hour 1 from--
chemicals emitted: 452023
emission rate (g/s): 0.15E+00
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 5.0E+01 2.8E+00 8.4E-01 2.6E-01 6.0E-02 2.2E-02 1.2E-02 8.3E-03 6.1E-03 4.7E-03 3.2E-03 2.4E-03
22.5 3.8E+01 2.1E+00 6.3E-01 1.9E-01 4.5E-02 1.6E-02 9.4E-03 6.3E-03 4.7E-03 3.7E-03 2.5E-03 1.9E-03
Calculated concentrations for hour 8 from--
chemicals emitted: 452023
emission rate (g/s): 0.16E+00
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 6.0E+01 3.5E+00 l.OE+00 3.2E-01 7.4E-02 2.7E-02 1.5E-02 9.8E-03 7.1E-03 5.5E-03 3.7E-03 2.7E-03
22.5 4.7E+01 2.7E+00 7.9E-01 2.4E-01 5.7E-02 2.1E-02 1.2E-02 7.8E-03 5.7E-03 4.5E-03 3.0E-03 2.3E-03
No Deposition Calculations Specified on Input ..
Figure 8-9 ASPENA diagnostic file created by example mobile source run
-------
plant FIPS number: 9001
plant ID: 16269
stack type: 0
Long/Lat coordinates : -73.269 41.142
urban/rural l=urban; 2=rural : 2
Species type : 0
ambient temperatures (k): 289.000 279.000 284.000
meteorological station: 4781
utm coordinates (km): -73.100 40.783
excluded stabilities: 000000
wind speeds: 000000
wind directions: 0000000000000000
Average Precip and freq : 110.2106 0.2067
Stack ID : 1
Long/Lat coordinates : -73.269 41.142
stack height (m): 8.90
diameter (m): 0.67
exit velocity (m/s): 12.00
exit temperature (k): 323.00
vent/stack class: stack
Calculated concentrations for hour 1 from--
chemicals emitted: 452020
emission rate (g/s): 0.12E+00
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 1.1E-01 1.1E+00 6.9E-01 4.2E-01 1.6E-01 6.7E-02 3.9E-02 2.7E-02 2.0E-02 1.6E-02 1.1E-02 8.3E-03
22.5 3.0E-01 1.2E+00 6.5E-01 3.5E-01 1.2E-01 5.0E-02 2.9E-02 2.0E-02 1.5E-02 1.2E-02 8.0E-03 6.0E-03
Calculated concentrations for hour 8 from--
chemicals emitted: 452020
emission rate (g/s): 0.12E+00
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing distance (km)
(deg) 0.10 0.50 1.00 2.00 5.00 10.00 15.00 20.00 25.00 30.00 40.00 50.00
0.0 9.5E-02 9.2E-01 7.3E-01 4.8E-01 1.9E-01 8.0E-02 4.7E-02 3.3E-02 2.4E-02 1.9E-02 1.3E-02 l.OE-02
22.5 2.0E-01 1.2E+00 7.3E-01 4.2E-01 1.5E-01 6.2E-02 3.6E-02 2.5E-02 1.8E-02 1.4E-02 l.OE-02 7.5E-03
No Deposition Calculations Specified on Input ..
plant FIPS number: 9001
plant ID: 16291
Figure 8-10 ASPENA diagnostic file created by example TRI source run
-------
8.1.5 Running ASPENB
Two types of input files are required to run ASPENB. The first is the normalized source
concentration/deposition output file from the ASPENA run. The second contains census tract
information, including tract data (format: binary) and a tract index file (format: binary). For the
purposes of this example, the tract data filenames are: "smptracts.dat" and "smptracts.ind". Note
that ASPENB requires that the tract data be located in the same directory as where the job is run.
Also, the tract data files are specified in the job file by their base name only. So, for the example
run, the census tract data file name is entered as smptract, with no suffix at the end. For a
detailed description of how to run ASPENB, see Section 3. The ASPENB job file for the
gaseous HAPs simulations is shown in Figure 8-11.
/bin/time aspenb « -eof-
POINT SOURCE FILE
TRACT FILE BASENAME
FILE LIST FILENAME
NO. SOURCE CATEGORY
RERUN (YES/NO)
-eof -
#
/bin/time aspenb « -eof-
aspena.tri.con
smptracts
runfile.1st
7
NO
ON ROAD MV FILE
TRACT FILE BASENAME
FILE LIST FILENAME
NO. SOURCE CATEGORY
RERUN (YES/NO)
-eof -
#
/bin/time aspenb « -eof-
aspena.mv.con
smptracts
runfile.1st
7
NO
AREA SOURCE FILE
TRACT FILE BASENAME
FILE LIST FILENAME
NO. SOURCE CATEGORY
RERUN (YES/NO)
-eof-
aspena.ar.con
smptracts
runfile.1st
7
NO
Figure 8-11 ASPENB example job file
ASEPENB creates a separate population concentration/deposition output file (format: binary) for
each HAP encountered in the ASPENA output file. The naming convention for the output file is
the 5-digit pollutant SAROAD code with an *.exp extension. For example, the ASPENB output
filename for toluene (SAROAD code = 45202) is 45202.exp.
The ASPENB module also provides an output file containing a list of all the names of processed
input ASPENA files. In the Figure 8-11 example, the name for the listing file is "runfile.lst"
8-10
-------
which contains the input normalized source concentration filenames ("aspena.tri.con",
"aspena.mv.con" and "aspena.ar.con" for the example).
Utility "exp2asci" converts the binary formatted ASPENB population concentration/deposition
file into ASCII format. Figure 8-12 presents an example of the binary to ASCII conversion using
"exp2asci". In the example, 45202.exp is the binary formatted ASPENB output, "smptracts" is
the census tract data file, and 7 is the number of source categories included in "45202.exp". The
utility generates the ASCII formatted output file named as "45202.txt".
rm 45202.txt/bin/time
exp2asci « -eof-
7
*.EXP FILENAME |45202.exp
TRACTS DATA FILE j smptracts
-eof-
Figure 8-12 Example EXP2ASCI job file
The ASCII formatted ASPENB output population concentration/deposition file generated by the
utility "exp2asci" for the example is presented in Figure 8-13.
8.1.6 Post-Processing Model Output
The ASPENB output files are in binary format and contain pollutant concentration estimates for
each of eight 3-hour time blocks for each source category. A series of software programs are
available to post-process the model output. Detailed descriptions of these programs are provided
in Section 4. (Deposition estimates are also contained in the ASPENB output files, but are not
treated by the post-processors.) For this example the following two post-processors are used:
AVGDAT - calculates the annual average HAP concentration for each source category,
and calculates the total annual average concentration over all categories
• EXTRDAT - converts the concentration data files from binary to ASCII format
Figure 8-14 presents an example job file for post-processing the example model output.
The ASPEN ASCII output for the example simulations is shown in Figure 8-15. It contains the
concentrations of toluene (in |ig/m3) by source category and census tract. The first two columns
are the state and county FIPS codes and tract FIPS code. The output displays annual average
concentrations for TRI, on-road mobile, manufacturing and non-manufacturing area sources,
under the CATOO, CAT03, CAT05 and CAT06 columns, respectively.
8-11
-------
9001 10101
O.OOOOOOE+00
O.OOOOOOE+00
0.331155E-02
O.OOOOOOE+00
0.422919E-03
O.OOOOOOE+00
O.OOOOOOE+00
9001 10102
O.OOOOOOE+00
O.OOOOOOE+00
0.361774E-02
O.OOOOOOE+00
0.545520E-03
O.OOOOOOE+00
O.OOOOOOE+00
9001 10201
O.OOOOOOE+00
O.OOOOOOE+00
0.579354E-02
O.OOOOOOE+00
0.670122E-03
O.OOOOOOE+00
O.OOOOOOE+00
9001 10202
O.OOOOOOE+00
O.OOOOOOE+00
0.952190E-02
O.OOOOOOE+00
0.929373E-03
O.OOOOOOE+00
O.OOOOOOE+00
36119 15000
O.OOOOOOE+00
O.OOOOOOE+00
0.112701E-02
O.OOOOOOE+00
0.924682E-04
O.OOOOOOE+00
O.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.632475E-03
.OOOOOOE+00
.OOOOOOE+00
.298845E-02
.OOOOOOE+00
.102578E-02
.OOOOOOE+00
.653247E-03
.OOOOOOE+00
.OOOOOOE+00
.521225E-02
.OOOOOOE+00
.126443E-02
.OOOOOOE+00
.844332E-03
.OOOOOOE+00
.OOOOOOE+00
.496717E-02
.OOOOOOE+00
.151366E-02
.OOOOOOE+00
.988371E-03
.OOOOOOE+00
.OOOOOOE+00
.766703E-02
.OOOOOOE+00
.199587E-02
.OOOOOOE+00
0.164685E-03
.OOOOOOE+00
.OOOOOOE+00
.303295E-02
.OOOOOOE+00
.128902E-03
.OOOOOOE+00
.OOOOOOE+00
45202
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.602951E-03
.OOOOOOE+00
.OOOOOOE+00
.196255E-02
.OOOOOOE+00
.456361E-03
.OOOOOOE+00
.731114E-03
.OOOOOOE+00
.OOOOOOE+00
.149818E-02
.OOOOOOE+00
.596893E-03
.OOOOOOE+00
.706242E-03
.OOOOOOE+00
.OOOOOOE+00
.297403E-02
.OOOOOOE+00
.722135E-03
.OOOOOOE+00
.806748E-03
.OOOOOOE+00
.OOOOOOE+00
.463139E-02
.OOOOOOE+00
.971293E-03
.OOOOOOE+00
0.494377E-03
.OOOOOOE+00
.OOOOOOE+00
.317063E-02
.OOOOOOE+00
.229063E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.385393E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.308918E-03
.317639E-03
.OOOOOOE+00
.435314E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.369893E-03
.431510E-03
.OOOOOOE+00
.493527E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.441517E-03
.421889E-03
.OOOOOOE+00
.578435E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.566090E-03
.533134E-03
.OOOOOOE+00
0.249541E-03
.OOOOOOE+00
.OOOOOOE+00
.582770E-03
.OOOOOOE+00
.316118E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.154866E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.297286E-03
.346642E-03
.OOOOOOE+00
.185383E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.388875E-03
.475560E-03
.OOOOOOE+00
.200628E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.455559E-03
.428519E-03
.OOOOOOE+00
.239344E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.604773E-03
.526697E-03
.OOOOOOE+00
0.138755E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.845961E-04
.242534E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.142112E-03
.OOOOOOE+00
.964551E-03
.OOOOOOE+00
.244506E-03
.415487E-03
.OOOOOOE+00
.165064E-03
.OOOOOOE+00
.631174E-03
.OOOOOOE+00
.317510E-03
.582221E-03
.OOOOOOE+00
.188866E-03
.OOOOOOE+00
.184324E-02
.OOOOOOE+00
.322872E-03
.415162E-03
.OOOOOOE+00
.226871E-03
.OOOOOOE+00
.272014E-02
.OOOOOOE+00
.404266E-03
.438111E-03
.OOOOOOE+00
0.129794E-03
.OOOOOOE+00
.OOOOOOE+00
.OOOOOOE+00
.227843E-03
.420564E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.224468E-03
.OOOOOOE+00
.123733E-02
.OOOOOOE+00
.311125E-03
.396137E-03
.OOOOOOE+00
.268752E-03
.OOOOOOE+00
.153372E-02
.OOOOOOE+00
.415000E-03
.591870E-03
.OOOOOOE+00
.277834E-03
.OOOOOOE+00
.203914E-02
.OOOOOOE+00
.383767E-03
.405331E-03
.OOOOOOE+00
.325602E-03
.OOOOOOE+00
.315319E-02
.OOOOOOE+00
.467594E-03
.454870E-03
.OOOOOOE+00
0.256117E-03
.OOOOOOE+00
.759098E-03
.OOOOOOE+00
.196333E-03
.713992E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.419884E-03
.OOOOOOE+00
.632815E-02
.OOOOOOE+00
.648992E-03
.OOOOOOE+00
.OOOOOOE+00
.468903E-03
.OOOOOOE+00
.709802E-02
.OOOOOOE+00
.892116E-03
.OOOOOOE+00
.OOOOOOE+00
.530698E-03
.OOOOOOE+00
.104112E-01
.OOOOOOE+00
.658951E-03
.OOOOOOE+00
.OOOOOOE+00
.615040E-03
.OOOOOOE+00
.154034E-01
.OOOOOOE+00
.699876E-03
.OOOOOOE+00
.OOOOOOE+00
0.936136E-03
.OOOOOOE+00
.277467E-03
.OOOOOOE+00
.389976E-03
.288280E-03
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.694393E-03
.OOOOOOE+00
.236211E-02
.OOOOOOE+00
.953998E-03
.OOOOOOE+00
.OOOOOOE+00
.896791E-03
.OOOOOOE+00
.232719E-02
.OOOOOOE+00
.141493E-02
.OOOOOOE+00
.OOOOOOE+00
.765232E-03
.OOOOOOE+00
.385490E-02
.OOOOOOE+00
.983919E-03
.OOOOOOE+00
.OOOOOOE+00
.862008E-03
.OOOOOOE+00
.614889E-02
.OOOOOOE+00
.110158E-02
.OOOOOOE+00
.OOOOOOE+00
0.485032E-03
.OOOOOOE+00
.146514E-02
.OOOOOOE+00
.112622E-02
.OOOOOOE+00
.OOOOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
OOOOOOE+00
OOOOOOE+00
143745E-02
OOOOOOE+00
176608E-03
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
175388E-02
OOOOOOE+00
231649E-03
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
274736E-02
OOOOOOE+00
214462E-03
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
447321E-02
OOOOOOE+00
261179E-03
OOOOOOE+00
OOOOOOE+00
OOOOOOE+00
103151E-02
OOOOOOE+00
702282E-03
OOOOOOE+00
OOOOOOE+00
Figure 8-13 ASPENB output population concentration/deposition file (in ASCII format) for the example run
8-12
-------
rm 45202.exp.avg
/bin/time avgdat « ieof
7
smptracts.1st
45202.exp.avg
45202
samples/
0.0
ieof
#
rm 45202.avg.out
/bin/time extravg « ieof
7
45202.exp.avg
45202.avg.out
45202
smptracts.1st
TOLUENE MGPCM 92.14
-1
ieof
Figure 8-14. Example post-processing job file
8-13
-------
Average
Concentrations
SAROAD Code 45202;
FIPS Code
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
9001
10101
10102
10201
10202
10300
10400
10500
10600
10700
10800
10900
11000
11100
11200
11300
20100
20200
20300
20400
20500
20600
20700
20800
20900
21000
21100
21200
21300
21400
21500
21600
21700
21800
21900
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CatOO
.4071E-
.4756E-
.5009E-
.5803E-
.4722E-
.4340E-
.4515E-
.4881E-
.5008E-
.5491E-
.6123E-
.5987E-
.5683E-
.4728E-
.4201E-
.7148E-
.5568E-
.5863E-
.6764E-
.6369E-
.6852E-
.7898E-
.7328E-
.8289E-
.8012E-
.8043E-
.7407E-
.6920E-
.6660E-
.6845E-
.7361E-
.7567E-
.8116E-
.8084E-
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Species
CatOl
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
OOOOE+
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
TOLUENE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Cat02
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
MGPCM
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Cat03
2574E-
2959E-
4329E-
6715E-
4025E-
3371E-
3839E-
4443E-
4796E-
6050E-
8710E-
8919E-
7246E-
4386E-
3389E-
1865E-
5354E-
5123E-
9716E-
7910E-
9828E-
1841E-
1478E-
3388E-
3328E-
4475E-
1967E-
1452E-
1225E-
1453E-
2144E-
2774E-
4962E-
6120E-
02
02
02
02
02
02
02
02
02
02
02
02
02
02
02
01
02
02
02
02
02
01
01
01
01
01
01
01
01
01
01
01
01
01
Cat04
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
O.OOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CatOS
3456E-
4748E-
4058E-
4805E-
3379E-
2958E-
3007E-
3357E-
3451E-
3952E-
4629E-
4178E-
3946E-
3135E-
2720E-
5490E-
7085E-
8751E-
1051E-
6095E-
7735E-
1179E-
8390E-
1113E-
8739E-
7977E-
7066E-
5808E-
5077E-
5155E-
6121E-
6457E-
7827E-
8278E-
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
02
03
03
02
03
02
03
03
03
03
03
03
03
03
03
03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Cat06
4447E-
5900E-
5989E-
7638E-
5220E-
4549E-
4812E-
5370E-
5588E-
6474E-
7809E-
7315E-
6777E-
5156E-
4376E-
1004E-
8610E-
1036E-
1486E-
9718E-
1250E-
2108E-
1434E-
2069E-
1602E-
1536E-
1251E-
1012E-
8898E-
9262E-
1105E-
1225E-
1540E-
1607E-
03
03
03
03
03
03
03
03
03
03
03
03
03
03
03
02
03
02
02
03
02
02
02
02
02
02
02
02
03
03
02
02
02
02
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bkgrd
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
OOOOE+00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
3771E-
4499E-
5834E-
8540E-
5357E-
4555E-
5072E-
5804E-
6201E-
7642E-
1057E-
1067E-
8887E-
5688E-
4519E-
2091E-
7481E-
7620E-
1293E-
1013E-
1254E-
2249E-
1778E-
3789E-
3655E-
4789E-
2237E-
1680E-
1431E-
1666E-
2389E-
3036E-
5276E-
6444E-
02
02
02
02
02
02
02
02
02
02
01
01
02
02
02
01
02
02
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
Figure 8-15 ASPEN output in ASCII format for the example simulation
8-14
-------
8.2 EXAMPLE 2 - PARTICIPATE HAPS
Figure 8-16 presents an emission/control input file for an example simulation to calculate ambient
concentrations of particulate HAPs from point source emissions. The input includes emissions of
chromium (fine) and nickel (fine) from a TRI source. Differences between this file and the example for
gaseous emissions from point sources are as follows:
7. Line 1: Both dry and wet depositions are selected in the example (= 0) for the fine particulate
HAPs (species type=l)
8. Lines 2-9: Reactive decay rates for particulate HAPs are all set to 0.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
TRI Point
0 . OOOe+00
0 . OOOe+00
0. OOOe+00
0. OOOe+00
0. OOOe+00
0. OOOe+00
0 . OOOe+00
0 . OOOe+00
9001
Sources
O.OOOe
O.OOOe
O.OOOe
O.OOOe
O.OOOe
O.OOOe
O.OOOe
O.OOOe
13777 -
1 -73.1483
801410 7
802160 7
.19e-05
.19e-05
Reactive Category 2 100
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
+ 00
73.
0.
0.
0.
0.
0.
0.
0.
0.
1483
OOOe+00
OOOe+00
OOOe+00
OOOe+00
OOOe+00
OOOe+00
OOOe+00
OOOe+00
41
41.1853 6.
7
7
19e-
19e-
05 7.
05 7.
0
0
0
0
0
0
0
0
. OOOe+00
. OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
. OOOe+00
. OOOe+00
0
0
0
0
0
0
0
0
. OOOe+00
. OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
. OOOe+00
. OOOe+00
0
0
0
0
0
0
0
0
. OOOe+00
. OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
.OOOe+00
. OOOe+00
. OOOe+00
.185301
10
19e
19e
0.
-05 7.
-05 7.
15
19e
19e
5.
-05 7.
-05 7.
00
19e
19e
308.0000 0.00 0.00
-05 7.19e-05 7.19e-05 7.19e-05
-05 7.19e-05 7.19e-05 7.19e-05
Figure 8-16 Example ASPENA input file for point source emits particulate HAPs
The other ASPEN model simulation and post-processing procedures for this example are the same as
those described for gaseous HAPs starting in Section 8.1.1.
8-15
-------
plant FIPS number: 9001 plant ID:
urban/rural l=urban; 2=rural : 1 Species type
13777 stack type:
: 1
0 Long/Lat coordinates
-73.148
41.185
ambient temperatures (k):
meteorological station:
utm coodinates (km):
excluded stabilities:
wind speeds:
wind directions:
289.000 279.000 284.000
4781
-73.100 40.783
000000
000000
0000000000000000
Average Precip and freq : 110.2106
Stack ID :
Long/Lat coordinates :
stack height (m):
diameter (m):
exit velocity (m/s):
exit temperature (k)
vent/stack class:
-73.148
6.10
0.15
5.00
308.00
stack
0.2067
41.185
Calculated concentations for hour 1 from--
chemicals emitted:
emission rate (g/s):
801410
0.72E-04
802160
0.72E-04
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing
(deg) 0.10
0.0 2.0E+01
22.5 1.8E+01
distance (km)
0.50 1.00 2.00
2.1E+00 6.5E-01 2.0E-01
1.6E+00 4.9E-01 1.5E-01
5.00
4.8E-02
3.5E-02
10.00
1.7E-02
1.3E-02
15.00
9.9E-03
7.5E-03
20.00
6.6E-03
5.1E-03
25.00
4.9E-03
3.7E-03
Calculated concentations for hour
from--
chemicals emitted:
emission rate (g/s):
801410
0.72E-04
802160
0.72E-04
receptor grid concentrations (micrograms/cubic meter) resulting from total emissions
bearing
(deg) 0.10 0.50
0.0 2.3E+01 2.6E+00
22.5 2.1E+01 2.0E+00
Total Deposition 1 from--
(deg) 0.10 0.50
0.0 3.1E+03 2.0E+02
22.5 3.5E+03 2.1E+02
distance (km)
1.00 2.00
7.9E-01 2.5E-01
6.1E-01 1.9E-01
1.00
5.6E+01
5.9E+01
2.00
1.6E+01
1.7E+01
5.00
5.9E-02
4.5E-02
5.00
3.7E+00
3.9E+00
10.00
2.1E-02
1.6E-02
10.00
1.4E+00
1.4E+00
15.00
1.2E-02
9.3E-03
15.00
3.0E-01
3.5E-01
20.00
7.8E-03
6.2E-03
20.00
5.6E-01
5.9E-01
25.00
5.7E-03
4.6E-03
25.00
4.3E-01
4.5E-01
30.00
3.8E-03
2.9E-03
30.00
4.4E-03
3.6E-03
30.00
3.4E-01
3.6E-01
40.00
2.6E-03
2.0E-03
40.00
3.0E-03
2.4E-03
50.00
1.9E-03
1.5E-03
50.00
2.2E-03
1.8E-03
40.00 50.00
2.4E-01 1.9E-01
2.6E-01 2.0E-01
Figure 8-17 ASPENA diagnostic file created by example point source run
-------
9001 10101 0.887709E-07 0.774276E-07 0.779782E-07 0.336689E-07 0.245561E-07 0.273105E-07 0.490938E-07 0.847798E-07 0.954688E-06
0.954688E-06
9001 10102 0.936549E-07 0.847418E-07 0.825023E-07 0.381454E-07 0.256891E-07 0.294738E-07 0.546769E-07 0.997266E-07 0.104341E-05
0.104341E-05
9001 10201 0.106153E-06 0.891512E-07 0.903393E-07 0.360951E-07 0.286658E-07 0.312934E-07 0.561904E-07 0.903312E-07 0.108410E-05
0.108410E-05
9001 10202 0.117312E-06 0.974810E-07 0.983083E-07 0.385422E-07 0.312283E-07 0.340161E-07 0.617253E-07 0.970862E-07 0.117850E-05
0.117850E-05
9001 10300 0.106110E-06 0.868497E-07 0.897928E-07 0.338026E-07 0.287059E-07 0.307150E-07 0.539455E-07 0.823316E-07 0.105309E-05
0.105309E-05
0 080141
Figure 8-18 ASPENB output population concentration/deposition file (in ASCII format) for example point source run (for Saroad code 80141)
9001 10101 0.887709E-07 0.774276E-07 0.779782E-07 0.336689E-07 0.245561E-07 0.273105E-07 0.490938E-07 0.847798E-07 0.954688E-06
0.954688E-06
9001 10102 0.936549E-07 0.847418E-07 0.825023E-07 0.381454E-07 0.256891E-07 0.294738E-07 0.546769E-07 0.997266E-07 0.104341E-05
0.104341E-05
9001 10201 0.106153E-06 0.891512E-07 0.903393E-07 0.360951E-07 0.286658E-07 0.312934E-07 0.561904E-07 0.903312E-07 0.108410E-05
0.108410E-05
9001 10202 0.117312E-06 0.974810E-07 0.983083E-07 0.385422E-07 0.312283E-07 0.340161E-07 0.617253E-07 0.970862E-07 0.117850E-05
0.117850E-05
9001 10300 0.106110E-06 0.868497E-07 0.897928E-07 0.338026E-07 0.287059E-07 0.307150E-07 0.539455E-07 0.823316E-07 0.105309E-05
0.105309E-05
0 080216
Figure 8-19 ASPENB output population concentration/deposition file (in ASCII format) for example point source run (for Saroad code 80216)
8-17
-------
9.0 REFERENCES
Briggs, G. A., 1974. Diffusion Estimates for Small Emissions. In ERL, ARL USAEC Report
ATDL-106. U.S. Atomic Energy Commission, Oak Ridge, Tennessee.
Briggs, G. A.,1975. Plume Rise Predictions. In Lectures on Air Pollution and Environmental
Impact Analyses. American Meteorological Society, Boston, Massachusetts.
EPA, 1992. User's Guide for the Industrial Source Complex (ISC2) Dispersion Models. Volume
H - Description of the Model Algorithms. EPA-450/4-92-008b. U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
McElroy, J.L. and Pooler, F., 1968. The St. Louis Dispersion Study. U.S. Public Health Service,
National Air Pollution Control Administration, Report AP-53.
Pasquill, F., 1976. Atmospheric Dispersion parameters in Gaussian Plume Modeling. Part II.
Possible Requirements for Change in the Turner Workbook Values. EPA-600/4-76/030b,
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina.
Rodhe, H., 1980. "Estimate of Wet Deposition Pollutants Around a Point Source," Atmospheric
Environment. 14. 1197-1199.
Rosenbaum, A.S., Ligocki, M.P., Wei, Y.H., 1998. Modeling Cumulative Outdoor
Concentrations of Hazardous Air Pollutants. Prepared for U.S. EPA Office of Policy,
Planning, and Evaluation. Prepared by, Systems Applications International, a division of
ICF Kaiser International (SYSAPP-98-96/33R1). Available on the World Wide Web at:
http://www.epa.gov/CumulativeExposure.
SAI, 1995. User's Guide to the Variable-Grid Urban Airshed Model (UAM-V). SYSAPP-
95/027. Systems Applications International, San Rafael, California.
Turner, D.G., 1970. Workbook of Atmospheric Dispersion Estimates. PHS Publication No. 999-
AP-26. U.S. Department of Health, Education, and Welfare, National Pollution Control
Administration, Cincinnati, Ohio.
9-1
-------
APPENDIX A ASPENA SUBROUTINE DESCRIPTIONS
ASPENA
Main driving routine for ASPENA model.
Called by: None
Calls to: HEADER, OPNFIL, POINT, STARIN
BID DISP
Adjusts dispersion parameters to account for buoyancy-induced dispersion.
Called by: GAUSS
Calls to: None
DDMPR
Calculates the distance dependent momentum plume rise.
Called by: PRISE
Calls to: None
DEPOS
Retrieves deposition velocities for specified wind speed and stability class
Called by: GAUSS
Calls to: None
GAUSS
Performs Gaussian plume computations for each point source.
Called by: STACK
Calls to: BID_DISP, DEPOS, PRISE, VERTF, VGAUSZ
GAUSSZ
Calculates vertical dispersion parameters at each radial distance for each stability class
assuming no wake effects.
Called by: POINT
Calls to: SIGMAZ
HEADER
Writes header information to output files.
Called by: ASPENA
Calls to: None
LIST
Writes point source data to output files.
Called by: POINT, STACK
Calls to: None
A-l
-------
OPNFIL
Opens and reads user input files.
Called by: ASPENA
Calls to: GETARG (System function)
POINT
Main routine to set up and process a single point source.
Called by: ASPENA
Calls to: GAUSSZ, LIST, SAVE, SKIP, STACK, STAR
PRISE
Calculates the plume rise for each type of plume (buoyant/momentum) and for each
atmospheric stability class (unstable/neutral/stable).
Called by: GAUSS
Calls to: DDMPR
SAVE
Updates and saves concentration and deposition grids for each point source and time
block
Called by: POINT, STACK
Calls to: None
SIGMAZ
Calculates the vertical dispersion parameter, oz, from dispersion curves as a function of
downwind distance, stability class, and rural/urban classification.
Called by: GAUSSZ, VGAUSZ
Calls to: SZCOEF
SKIP
Routine to read point and stack parameters for "skipped" points. "Skipped" points are
those for which the STAR data from previously processed point is used.
Called by: POINT
Calls to: None
STACK
Main routine to process individual point sources.
Called by: POINT
Calls to: GAUSS, LIST, SAVE
STAR
Sets up STAR data for current plant.
Called by: POINT
Calls to: None
A-2
-------
STARIN
Reads STAR data file and creates index of STAR stations.
Called by: ASPENA
Calls to: None
SZCOEF
Determines coefficients and ranges for calculation of rural dispersion
parameter.
Called by: SIGMAZ
Calls to: None
VERT
Computes the Vertical Term for use in Gaussian plume equation.
Called by: GAUSS
Calls to: None
VGAUSZ
Calculates vertical dispersion parameter with wake effects using virtual distances.
Called by: GAUSS
Calls to: SIGMAZ
A-3
-------
APPENDIX B ASPENA COMMON BLOCKS
Parameters
MXSTA = 500 - maximum number of met stations
MXSPEC = 150 - maximum number of species in run
common/srcblk/ :
ifips
utmx,utmy
itype
iurb
isptyp
idsrce
common/metblk/ :
istar
nosc(6)
nows(6)
nowd(16)
atemp(6)
fp
P
common/grdblk/ :
nr
rad(12)
common/stkblk/ :
rlon,rlat
stakh
stakd
stakv
stakt
ivent
ibldg
bldw
bldh
idstk
information concerning sources
plant FIPS code
plant location
source type
urban/rural flag
species type
source ID
INTEGER
REAL
INTEGER
INTEGER
INTEGER
CHAR
information
INTEGER
INTEGER
INTEGER
INTEGER
REAL
REAL
REAL
concerning STAR met data
INWS index
array of excluded stability classes
array of excluded wind speeds
array of excluded wind directions
array of temperatures
frequency of precipitation
annual average precipitation
information concerning radial receptor grid locations
INTEGER number of radial grid locations
REAL radial distance to receptor locations
information concerning stacks
REAL stack location
REAL stack height
REAL stack diameter
REAL stack exit gas velocity
REAL stack exit gas temperature
INTEGER stack/vent flag
INTEGER building downwash flag
REAL building width
REAL building height
CHAR stack ID
common/chmblk/ :
nchem
idchem
q(mxspec,8)
dk(6,8)
information concerning chemical species
INTEGER number of chemical species
INTEGER chemical ID
REAL emission rates
REAL reactive decay rates
B-l
-------
common/oldblk/ :
olda
comon/sigblk/ :
sigz(12,6)
vsigz(12,6)
delta(6)
common/conblk/ :
c(16,12)
common/dep/
depl(16,12)
dep2(16,12)
dep3(16,12)
depw(16,12)
iddep
iwdep
common/runblc/
idrun
idfile
information concerning building downwash
REAL area of nearby building at last stack
information concerning vertical dispersion parameters
REAL vertical dispersion without wake effects
REAL vertical dispersion with wake effects
REAL contribution to vertical distance due to building
information concerning ambient concentrations
REAL ambient concentrations
information concerning depositions
REAL dry deposition flux to land
REAL dry deposition flux to agricultural land
REAL dry deposition flux to water
REAL wet deposition flux
INTEGER dry deposition flag
INTEGER wet deposition flag
information concerning run ID
CHAR run ID
CHAR run filename
common/runblk/ :
inps(10)
invers
common/stablk/
LOGICAL
INTERGER
information concerning met data
nsta INTEGER
ista(mxsta) INTEGER
stax, stay(mxsta)REAL
stas(8, mxsta) REAL
htmi(8, mxsta)REAL
atmp(3, mxsta)REAL
fps(mxsta) REAL
p(mxsta) REAL
number of met stations
met station ID
met station location
average wind speeds
mixing heights
average temperatures
precipitation frequencies
precipitation amounts
common/lmet/
: information concerning various options
Ipsuedo LOGICAL flag indicating pseudo-point
Istrec INTEGER index of last record processed
Iskp LOGICAL flag indicating that station is skipped
irec INTEGER index of current record
iurblst INTEGER urban/rural flag of last processed source
B-2
-------
common/maxcon/ : information concerning concentrations
xc(16,12) REAL array of maximum concentrations
xcavg(16,12) REAL array of average concentrations
common/totdep/ : information concerning total depositions
deptot(16,12,3)REAL array of total depositions
B-3
-------
APPENDIX C INPUT AND OUTPUT FILE FORMATS
C.I DESCRIPTION OF ASPEN INPUT FILE CONTENT AND FORMAT
C.I.I Description of Emission/Control File
Table C-l Description of Emission/Control File
Record No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Variables
IDRUN
IDFILE
ISPTYP
IDDEP
IWDEP
DK(IC,1)
DK(IC,2)
DK(IC,3)
DK(IC,4)
DK(IC,5)
DK(IC,6)
DK(IC,7)
DK(IC,8)
IFIPS
IDSRC
UTMX
UTMY
ITYPE
IURB
INWS
NOSC(6)
NOWS(6)
NOWD(6)
RAD (12)
IDSTK
RLON
RLAT
STAKH
STAKD
STAKV
STAKT
FVENT
IBLDG
BLOW
BLDH
IDCHEM
Q
Format
A40
A20
11
11
11
6F10
6F10
6F10
6F10
6F10
6F10
6F10
6F10
15
A10
F10
F10
11
11
15
611
611
611
12F5
A5
F10
F10
F10
F10
F10
F10
11
11
F10
F10
16
8F10
Description
Run identification
Emission file identifier
Species type (0 = gas; 1 = fine part.; 2 = coarse part.)
= 0, include dry deposition; = 1, no dry deposition
= 0, include wet deposition; = 1, no wet deposition
Decay rates for 6 stability classes for time block 1
Decay rates for 6 stability classes for time block 2
Decay rates for 6 stability classes for time block 3
Decay rates for 6 stability classes for time block 4
Decay rates for 6 stability classes for time block 5
Decay rates for 6 stability classes for time block 6
Decay rates for 6 stability classes for time block 7
Decay rates for 6 stability classes for time block 8
State/County FIPS
Plant ID for points; census tract no. for pseudo points
Longitude (decimal degrees)
Latitude (decimal degrees)
Source type (0 or blank for points; 3 = pseudo points)
Urban/Rural flag (1 = urban; 2 = rural)
Star station (NWS) ID (blank or 0 = use nearest station)
Excluded stability classes
Excluded wind speeds
Excluded wind direction
Polar grid radial distances (km) (blank - use defaults)
Stack ID for points; FIPS code for pseudo points
Longitude (decimal degrees)
Latitude (decimal degrees)
Stack height (m)
Stack exit diameter (m)
Stack exit velocity (m/sec)
Stack exit temperature (Deg K)
Vent/Stack flag (0 = stacked; 1 = non-stacked)
Build flag (0 = no building; 1 = building)
Width of nearby building (m)
Height of nearby building (m)
5 -digit Saroad code plus 1 -digit source category code
Emissions (g/sec) for eight 3-hour time blocks
C-l
-------
Note:
UTMX/UTMY and RLON/RLAT specify the locations of point sources, or the locations
of the census tract centroid for pseudo point sources (i.e., area and mobile sources).
Record 14 is repeated for each HAP emitted from the stack or census tract.
• Records 10 through 14 are repeated for each facility or census tract, followed by two
blank lines to indicate the end of the data record for the facility or census tract
• The emission record of the last facility or census tract will be followed by five blank lines
to indicate the end of the file.
• For multiple pseudo point sources that use meteorological data from the same STAR
station, and that have the same urban/rural designation, ASPEN will calculate the same
normalized concentration/deposition receptor grid. To save computing time, the emission
records for pseudo point sources should be entered so that all sources that will use the
same meteorological station ID (NWS ID) and urban/rural designation are grouped
together. ASPEN checks for this grouping, and omits redundant calculations. This is the
preferred method for treating pseudo-point since the code will not need to re-search the
STAR data for the appropriate station since the data will already be stored in memory.
C.I.2 Description of Meteorological Index File
The meteorological index file is in binary format. There is one record for each STAR station
containing the following information.
Table C-2 Description of meteorological index file
Variables
ISTA
STAX
STAY
ATEMP (1)
ATEMP (2)
ATEMP (3)
PS
FPS
STAS
HTMI
Data Type
Integer
Real
Real
Real
Real
Real
Real
Real
Real
Real
Description
Star (NWS) station ID
Longitude of the station (decimal degree)
Latitude of the station (decimal degree)
Annual average daily maximum temperature (Deg K)
Annual average daily minimum temperature (Deg K)
Annual average temperature (Deg K)
Annual average precipitation (cm)
Fraction of time with precipitation
Not used (eight zeros)
Annual average mixing heights for eight 3 -hour time
blocks
C. 1.3 Description of STAR Data
The STAR input file is in binary format Each record contains the STAR data for one time block
of one star station, and includes the following variables.
C-2
-------
Table C-3 Description of STAR Data
Variables
IWB
fflR
FSTAR (nd, ns, nc)
Data Type
Integer
Integer
Real
Description
Star (NWS) station ID
Time block number
STAR data for the time block
nd = number of wind directions (16)
ns: = number of stability classes (6)
nc = number of wind speed categories (6)
C. 1.4 Description of Census Tract Index File
The census tract index file is in binary format, and it contains the following variables.
Table C-4 Description of census tract index file
Record No.
1
2
3
Variables
NSTATES
NCOUNTIES
NTRACTS
STFIP
STMNLN
STMNLT
STMXLN
STMXLT
COPTR
NUMCO
COFIPS
COMNLN
COMNLT
COMXLN
COMXLT
TRPTR
NUMTR
Data Type
Integer
Integer
Integer
Integer
Real
Real
Real
Real
Integer
Integer
Integer
Real
Real
Real
Real
Integer
Integer
Description
Total number of states included in the data
Total number of counties included in the
data
Total number of tracts included in the data
State FIPS code
State minimum longitude (decimal degree)
State minimum latitude (decimal degree)
State maximum longitude (decimal degree)
State maximum latitude (decimal degree)
Pointer to the first county in the state
Total number of counties in the state
County FIPS code
County minimum longitude (decimal
degree)
County minimum latitude (decimal degree)
County maximum longitude (decimal
degree)
County maximum latitude (decimal
degree)
Pointer to the first tract in the county
Total number of tracts in the county
Note:
Record 2 is repeated for all states included in the census tract data file.
Record 3 is repeated for all counties included in the census tracts data file.
C-3
-------
C. 1.5 Description of Census Tract Data
The census tract data is in binary format. There is one record for each census tract containing the
following variables.
Table C-5 Description of census tract data
Variables
TRFIPS
TRLON
TRLAT
UFLAG
TRRAD
Data
Type
Integer
Real
Real
Integer
Real
Description
State/County FIPS code, tract FIPS code
Longitude of the tract centroid (decimal degree)
Latitude of the tract centroid (decimal degree)
Urban/Rural flag of the tract (1 = urban; 2 = rural)
Hypothetical tract radius (m)
C.2 DESCRIPTION OF ASPEN OUTPUT FILE CONTENT AND FORMAT
C.2.1 Description of Normalized Source Concentration/Deposition File
The normalized source concentration/deposition file is the output of the ASPEN dispersion
module (ASPENA) and input to the ASPEN mapping module (ASPENB). It is in binary format.
C-4
-------
Table C-6 Description of Normalized Source Concentration/Deposition File
Record
No.
1
2
4
5
6
7
Variables
ID
VERSION
IDSRC
IDSTAK
ITYPE
RLON
RLAT
IURB
NCHEM
ICHEM(I),(RATE
(I,J),J=1,NUMGR
D),I=1, NCHEM)
NC
R(I),I=1,NC
NL
F
(C(I,J,K),I=1,NL),
J=1,NC
(DUL(I,J),I=1,NL)
,J=1,NC
(DRL(I,J),I=1,NL)
,J=1,NC
(DW(I,J),I=1,NL),
J=1,NC
Data Type
Character
Integer
Character
Character
Integer
Real
Real
Integer
Integer
Integer
Real
Integer
Real
Integer
Real
Real
Real
Real
Real
Description
Emission file identifier
Version number
Plant ID for points; census tract no. for pseudo points
Stack ID for points; FIPS code for pseudo points
Source type
Longitude (decimal degree)
Latitude (decimal degree)
Urban/Rural flag
Number of HAPs with emissions
5 -digit HAP SAROAD code plus 1 -digit source
category code,
emission rates for eight 3 -hour time blocks
Number of radial distances
Polar grid radial distances (km)
Number of azimuth direction
Start bearing (0 degree)
Normalized concentration for the receptor grid
Normalized urban land deposition for the receptor grid
Normalized rural land deposition for the receptor grid
Normalized wet deposition for the receptor grid
Note:
Record 4 is repeated for each of eight 3-hour time blocks.
Record 2 through record 7 is repeated for each facility or census tract.
C.2.2 Description of Population Concentration/Deposition File
The population concentration/deposition file is the output of the ASPEN mapping module
(ASPENB). It is in binary format. There is one record for each census tract containing the
following information.
C-5
-------
Table C-7 Description of Population Concentration/Deposition File
Variables Data Type Description
STCO Integer State/County FIPS code
TRACT Integer Census tract FIPS code
CONC Real concentration in eight 3-hour time blocks (|ig/m3) for each source
category
DLAND Real deposition flux on land (|ig/m2-day) for each source category
DWATER Real deposition flux on water (ng/m2-day) for each source category
An empty record with zeros for the first two fields, followed by the 5-digit HAP SAROAD code
and zeros for the rest of nine fields, indicates the end of the file.
C.2.3 Description of Source Listing File
The source listing file is the output of the ASPEN dispersion module (ASPENA) used for
purpose of quality assurance. It is in ASCII format. There is one record for each emission
source processed by ASPENA, containing the following variables.
Table C-8 Description of source listing file
Variables
IFIPS
IDSRCE
UTMX
UTMY
ITYPE
IURB
Data Type
Integer
Character
Real
Real
Integer
Integer
Description
State/County FIPS code
Plant ID for points; census tract no. for pseudo points
Longitude (decimal degrees)
Latitude (decimal degrees)
Source type (0 or blank for points; 3 = pseudo points)
Urban/Rural flag ( 1 = urban; 2 = rural)
The last record of the source listing contains zeros for the variables to indicate the end of the file.
C.2.4 Description of the Listing File
The listing file is an output file of the ASPEN mapping module (ASPENB). It lists the
normalized source concentration/deposition input filenames processed by ASPENB. ASPENB
checks this file each time a simulation is started to prevent processing a file twice.
C-6
-------
C.3 DECAY RATES BY REACTIVITY CLASS
Reactivity Class 1 - non reactive
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
Reactivity Class
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
Reactivity Class
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
0.
0.
0.
0.
0.
0
0
0
A
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
2 -paniculate
0
0
0
0
0
0
0
0
A
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
3 -paniculate
0
0
0
0
0
0
0
0
A
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
B
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
.OOE+01
.OOE+01
0.
0.
0.
0.
0.
c
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
O.OOE+01
0.
0.
OOE+01
OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
D
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
.OOE+01
.OOE+01
0.
0.
0.
0.
0.
E
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
O.OOE+01
0
0
.OOE+01
.OOE+01
F
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
matter (five)
0.
0.
0.
0.
0.
0.
0.
0.
B
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
C
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
D
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
0
0
0
0
0
0
0
0
E
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
F
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
matter (coarse)
0.
0.
0.
0.
0.
0.
0.
0.
B
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
C
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
OOE+01
0.
0.
0.
0.
0.
0.
0.
0.
D
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
0
0
0
0
0
0
0
0
E
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
.OOE+01
F
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
O.OOE+01
Each pollutant is assigned a reactivity class (Rosenbaum, et al., 1998)
C-7
-------
Reactivity Class 4 - medium low reactivity
Stability Class
Time
Time
Time
Time
Time
Time
Time
Time
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
Reactivity Class
9.
9.
1.
7.
6.
2.
1.
9
A
.87E-07
.87E-07
.18E-05
.89E-05
.71E-05
.37E-05
.97E-06
.87E-07
B
9.87E-07
9.87E-07
7.89E-06
5.92E-05
5.13E-05
1.78E-05
1.97E-06
9.87E-07
9.
9.
3.
C
.87E-07
.87E-07
.95E-06
3.95E-05
3.
1.
1.
9
.55E-05
.18E-05
.97E-06
.87E-07
9
9
1
1
1
7
9
D
.87E-07
.87E-07
.97E-06
.97E-05
.97E-05
.89E-06
.87E-07
9.87E-07
9.
9.
9.
9.
9.
9.
9.
9
E
.87E-07
.87E-07
.87E-07
.87E-07
.87E-07
.87E-07
.87E-07
.87E-07
F
9.87E-07
9.87E-07
9.87E-07
9.87E-07
9.87E-07
9.87E-07
9.87E-07
9.87E-07
5 - medium reactivity
Stability Class
Time
Time
Time
Time
Time
Time
Time
Time
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
Reactivity Class
2
2
2
1
1
5
4
2
A
.47E-06
.47E-06
.96E-05
.97E-04
.68E-04
.92E-05
.93E-06
.47E-06
B
2.47E-06
2.47E-06
1.97E-05
1.48E-04
1.28E-04
4.44E-05
4.93E-06
2.47E-06
2
2
9
9
8
2
4
2
C
.47E-06
.47E-06
.87E-06
.87E-05
.88E-05
.96E-05
.93E-06
.47E-06
2
D
.47E-06
2.47E-06
4
4
4
1
2
.93E-06
.93E-05
.93E-05
.97E-05
.47E-06
2.47E-06
2
2
2
2
2
2
2
2
E
.47E-06
.47E-06
.47E-06
.47E-06
.47E-06
.47E-06
.47E-06
.47E-06
F
2.47E-06
2.47E-06
2.47E-06
2.47E-06
2.47E-06
2.47E-06
2.47E-06
2.47E-06
(5 - medium high reactivity
Stability Class
Time
Time
Time
Time
Time
Time
Time
Time
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
4
4
5
O
3
1
9
4
A
.93E-06
.93E-06
.92E-05
.95E-04
.35E-04
.18E-04
.87E-06
.93E-06
B
4.93E-06
4.93E-06
3.95E-05
2.96E-04
2.57E-04
8.88E-05
9.87E-06
4.93E-06
4
4
1
1
1
5
9
4
C
.93E-06
.93E-06
.97E-05
.97E-04
.78E-04
.92E-05
.87E-06
.93E-06
4
4
9
9
9
D
.93E-06
.93E-06
.87E-06
.87E-05
.87E-05
3.95E-05
4
4
.93E-06
.93E-06
4
4
4
4
4
4
4
4
E
.93E-06
.93E-06
.93E-06
.93E-06
.93E-06
.93E-06
.93E-06
.93E-06
F
4.93E-06
4.93E-06
4.93E-06
4.93E-06
4.93E-06
4.93E-06
4.93E-06
4.93E-06
-------
Reactivity Class 7 - very high reactivity
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
Reactivity Class
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
Reactivity Class
Stability Class
Time Block 1
Time Block 2
Time Block 3
Time Block 4
Time Block 5
Time Block 6
Time Block 7
Time Block 8
5.
A
.01E-04
3.21E-05
9.
5.
5.
1.
3.
5
.OOE-05
.93E-04
.04E-04
.79E-04
.95E-05
.01E-04
B
5.01E-04
3.21E-05
6.04E-05
4.45E-04
3.86E-04
1.34E-04
3.95E-05
5.01E-04
5.
3.
C
.01E-04
.21E-05
3.08E-05
2.
.97E-04
2.67E-04
9.
3.
5
.OOE-05
.95E-05
.01E-04
5
O
J
1
1
1
5
D
.01E-04
.21E-05
.60E-05
.49E-04
.49E-04
.99E-05
3.21E-05
5
.01E-04
5.
5.
5.
8.
8.
8.
5.
5
E
.01E-04
.01E-04
.01E-04
.14E-06
.14E-06
.14E-06
.01E-04
.01E-04
5
5
5
8
8
8
F
.01E-04
.01E-04
.01E-04
.14E-06
.14E-06
.14E-06
5.01E-04
5
.01E-04
8 - high reactivity
1
1
1
9
8
2
2
1
A
.23E-05
.23E-05
.48E-04
.87E-04
.39E-04
.96E-04
.47E-05
.23E-05
B
1.23E-05
1.23E-05
9.87E-05
7.40E-04
6.41E-04
2.22E-04
2.47E-05
1.23E-05
1
1
4
4
4
1
2
1
C
.23E-05
.23E-05
.93E-05
.93E-04
.44E-04
.48E-04
.47E-05
.23E-05
1
1
D
.23E-05
.23E-05
2.47E-05
2
.47E-04
2.47E-04
9
1
1
.87E-05
.23E-05
.23E-05
1
1
1
1
1
1
1
1
E
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
1
1
1
1
1
1
1
1
F
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
.23E-05
9 - low reactivity
4
4
5
3
O
J
i
9
4
A
.94E-07
.94E-07
.90E-06
.94E-05
.36E-05
.19E-05
.85E-07
.94E-07
B
4.94E-07
4.94E-07
3.95E-06
2.96E-05
2.57E-05
8.90E-06
9.85E-07
4.94E-07
4
4
1
1
1
5
9
4
C
.94E-07
.94E-07
.98E-06
.97E-05
.78E-05
.90E-06
.85E-07
.94E-07
4
4
9
9
9
3
4
4
D
.94E-07
.94E-07
.85E-07
.85E-06
.85E-06
.95E-06
.94E-07
.94E-07
4
4
4
4
4
4
4
4
E
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
4
4
4
4
4
4
4
4
F
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
.94E-07
C-9
-------
APPENDIX D GLOSSARY
ASPEN — Assessment System for Population Exposure Nationwide
ASCII — American Standard Code for Information Interchange, a standard set of codes used by
computers and communication devices. Sometimes used to refer to files containing only such
standard codes, without any application-specific codes such as might be present in a document
file from a word processor program.
Binary File — A file written without the use of a FORTRAN FORMAT statement.
Directory — A logical subdivision of a disk used to organize files stored on a disk.
Dispersion Model — A group of related mathematical algorithms used to estimate (model) the
dispersion of pollutants in the atmosphere due to transport by the mean (average) wind and small
scale turbulence.
DOS — Disk Operating System. Software that manages applications software and provides an
interface between applications and the system hardware components, such as the disk drive,
terminal, and keyboard.
EPA — U. S. Environmental Protection Agency.
Error message — A message written by the model to the error/message file whenever an error is
encountered that will inhibit data processing.
ISCLT — Industrial Source Complex - Long Term Dispersion Model.
Joint Frequency Distribution — The joint frequency of wind direction sector, wind speed class
and stability category (see also STAR).
Mixing Height — The depth through which atmospheric pollutants are typically mixed by
dispersive processes.
Pasquill Stability Categories — A classification of the dispersive capacity of the atmosphere,
originally defined using surface wind speed, solar insulation (daytime) and cloudiness
(nighttime). They have since been reinterpreted using various other meteorological variables.
STAR — STability ARray, a joint frequency distribution summary of stability category, wind
speed and wind direction. The STAR data are used as input for the ISC Long Term dispersion
model.
D-l
-------
Station Identification — An integer or character string used to uniquely identify a station or site as
provided in the upper air (TD-5600 and TD-6201), mixing height (TD-9689), and surface
weather (CD-144 and TD-3280) data formats available from NCDC.
Syntax — The order, structure and arrangement of the inputs that make of the input runstream
file, specifically, the rules governing the placement of the various input elements including
pathway IDs, keywords, and parameters.
Wind Profile Exponent — The value of the exponent used to specify the profile of wind speed
with height according to the power law (see Section 1.1.3 of Volume n).
D-2
-------
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-454/R-00-017
RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
USER'S GUIDE for the ASSESSMENT SYSTEM FOR POPULATION
EXPOSURE NATIONWIDE MODEL (ASPEN, VERSION 1.1)
5. REPORT DATE
April 2000
6. PERFORMING ORGANIZATION CODE
AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
EPA Contract No. 68D98006
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions, Monitoring & Analysis Division
Research Triangle Park, NC 27711
Final Report
SUPPLEMENTARY NOTES
EPA Work Assignment Manager: Jawad S. Touma
16. ABSTRACT
This user's guide provides documentation for the Assessment System for Population
Exposure Nationwide (ASPEN, Version 1.1), referred to hereafter as ASPEN. It includes
a technical description of the ASPEN algorithms, user instructions for running the
model and a tutorial for getting started. The ASPEN model consists of a dispersion and
mapping module. The dispersion module is a Guassian formulation for estimating ambient
annual average concentrations at a set of fixed receptors within the vicinity of the
emission source. The mapping module produces a concentration at each census tract.
Input data needed are emissions data, meteorological data and census tract data.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
Air Pollution
Air Quality Dispersion Models
Meteorology
Air Toxics
18. DISTRIBUTION STATEMENT
Release Unlimited
SECURITY CLASS (Report)
Unclassified
20. SECURITY CLASS (Page)
Unclassified
21. NO. OF PAGES
109
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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