ADDENDUM
USER'S GUIDE FOR THE
AMS/EPA REGULATORY MODEL - AERMOD
(EPA-454/B-03-001, September 2004)
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, North Carolina 27711
September 2009
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PREFACE
This document provides updated user instructions for the AERMOD dispersion model,
including modifications introduced with version 06341 and later. This addendum supplements
and updates the information contained in the current AERMOD User's Guide (EPA, 2004a).
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ACKNOWLEDGEMENTS
Portions of this Addendum to the "User's Guide for the AMS/EPA Regulatory Model -
AERMOD" related to the PSDCREDIT option for the Plume Volume Molar Ratio Method
(PVMRM) were prepared by MACTEC Federal Programs, Inc., Research Triangle Park, North
Carolina. This effort was funded by the Environmental Protection Agency, Region 10, under
Contract No. EP-D-05-096, with Herman Wong as the Work Assignment Manager (WAM).
in
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CONTENTS
PREFACE ii
ACKNOWLEDGEMENTS iii
TABLES vi
1.0 INTRODUCTION 1
1.1 OVERVIEW OF AERMOD REVISIONS 1
1.2 BACKGROUND ON DEPOSITION ALGORITHMS 3
2.0 USER INSTRUCTIONS 6
2.1 DISPERSION MODELING OPTIONS 6
2.1.1MODELOPT Keyword 6
2.1.2 BETA Test Options 10
2.1.3 Processing for Paniculate Matter (PM) NAAQS 11
2.1.4 Specifying Multiple Urban Areas 14
2.1.5 BETA Options for Capped and Horizontal Stack Releases 15
2.2 DEPOSITION ALGORITHM INPUTS AND OPTIONS 17
2.2.1 Definition of Seasons for Gas Dry Deposition 17
2.2.2 Definition of Land Use Categories for Gas Dry Deposition 18
2.2.3 Option for Overriding Default Parameters for Gas Dry Deposition 19
2.2.4 Specifying Source Parameters for Gas Deposition (Dry and/or Wet) 20
2.2.5 Option for Specifying the Deposition Velocity for Gas Dry Deposition 20
2.2.6 Specifying Source Parameters for Particle Deposition 21
2.2.7 Specifying Emission and Output Units 23
2.2.8 Deposition Velocity and Resistance Outputs 24
2.2.9 Meteorological Data for Deposition Algorithms 25
2.3 OPEN PIT SOURCE OPTION 26
2.4 PVMRM AND OLM OPTIONS FOR MODELING NO2 28
2.4.1 Specifying Ozone Concentrations for PVMRM and OLM Options 29
2.4.2 Specifying the Ambient Equilibrium NO2/NOx Ratio for PVMRM 30
2.4.3 Specifying the Default In-stack NO2/NOx Ratio for PVMRM and OLM 31
2.4.4 Specifying In-stack NO2/NOx Ratios by Source for PVMRM and OLM 31
2.4.5 Specifying Combined Plumes for OLM 32
2.4.6 Modeling NO2 Increment Credits with PVMRM 34
2.5 VARIABLE EMISSION RATES 39
2.5.1 Specifying Variable Emission Factors (EMISFACT) 39
2.5.2 Specifying an Hourly Emission Rate File (HOUREMIS) 43
2.6 OUTPUT FILE OPTIONS 45
2.7 MODEL STORAGE LIMITS 46
3.0 REFERENCES 48
APPENDIX A. ALPHABETICAL KEYWORD REFERENCE A-l
IV
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APPENDIX B. FUNCTIONAL KEYWORD/PARAMETER REFERENCE B-l
APPENDIX C. LIST OF ERROR/WARNING MESS AGES C-l
APPENDIX D. EPA Model Clearinghouse Memorandum Dated July 9, 1993 D-1
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TABLES
Table Page
1-1. Summary of Deposition Options in AERMOD 5
B-l. DESCRIPTION OF CONTROL PATHWAY KEYWORDS B-3
B-2. DESCRIPTION OF CONTROL PATHWAY KEYWORDS AND PARAMETERS... B-5
B-3. DESCRIPTION OF SOURCE PATHWAY KEYWORDS B-9
B-4. DESCRIPTION OF SOURCE PATHWAY KEYWORDS AND PARAMETERS .... B-11
B-5. DESCRIPTION OF RECEPTOR PATHWAY KEYWORDS B-16
B-6. DESCRIPTION OF RECEPTOR PATHWAY KEYWORDS AND
PARAMETERS B-17
B-7. DESCRIPTION OF METEOROLOGY PATHWAY KEYWORDS B-20
B-8. DESCRIPTION OF METEOROLOGY PATHWAY KEYWORDS AND
PARAMETERS B-21
B-9. DESCRIPTION OF EVENT PATHWAY KEYWORDS B-23
B-10. DESCRIPTION OF EVENT PATHWAY KEYWORDS AND PARAMETERS B-24
B-ll. DESCRIPTION OF OUTPUT PATHWAY KEYWORDS B-25
B-12. DESCRIPTION OF OUTPUT PATHWAY KEYWORDS AND PARAMETERS .... B-26
VI
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1.0 INTRODUCTION
1.1 OVERVIEW OF AERMOD REVISIONS
This document provides user instructions for revisions to the AERMOD dispersion
model. The discussion provided here supplements and updates the information contained in the
current AERMOD User's Guide (EPA, 2004a), and it is assumed that the reader is already
familiar with the contents of that document. Note that portions of the current AERMOD User's
Guide (EPA, 2004a) are no longer valid or applicable.
Four sets of AERMOD revisions are included in this Addendum:
1. The first set of revisions, first introduced with version 03273 of AERMOD,
includes dry and wet deposition algorithms for both particulate and gaseous
emissions (see Sections 1.2 and 2.2 for more details), and the OPENPIT source
option, originally incorporated in the ISCST3 model (EPA, 1995a), for modeling
particulate emissions from open pit (below grade) sources, such as surface coal
mines and rock quarries;
2. The second set of revisions, first introduced with version 04300 of AERMOD,
includes two non-DFAULT options for modeling conversion of NOX to NO2: 1) the
Plume Volume Molar Ratio Method (PVMRM) (Hanrahan, 1999a and 1999b); and
2) the Ozone Limiting Method (OLM);
3. The third set of revisions, first introduced with version 06341 of AERMOD,
includes the following:
a. A new "BETA" option on the CO MODELOPT card to allow for new features
to be added to AERMOD that are still in BETA-test status;
b. A BETA option for incorporating NO/NO2 chemistry for NO2 increment
consumption calculations with PSD credits using the PVMRM option;
c. BETA options for capped and horizontal stack releases;
d. An option to specify an initial default in-stack NO2/NOX ratio for the PVMRM
and OLM options;
e. New options for varying emissions by month, hour-of-day, and day-of-week
(MHRDOW and MHRDOW7);
f. An option to allow multiple urban areas to be defined in a single model run;
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g. Updated processing to support modeling demonstrations for the National
Ambient Air Quality Standards (NAAQS) for PM, including the 24-hour
average design value for PM-2.5 impacts; and
h. Use of dynamic array allocation for AREAPOLY sources to allocate array
limits for the maximum number of vertices at model runtime, replacing the
previous fixed array limit of 20 vertices.
4. The fourth set of revisions, first introduced with version 09260 of AERMOD,
includes the following (additional information is provided in Model Change
Bulletin (MCB) #3 provided on the SCRAM AERMOD webpage):
a. New options for varying emissions by hour-of-day and day-of-week (HRDOW
and HRDOW7);
b. Modification of the regulatory default option (DFAULT) on the CO
MODELOPT card to impose a restriction on the urban roughness length
parameter to be 1 meter for regulatory default applications. Any value other
than 1 meter for the urban roughness length option on the CO URBANOPT
card will be treated as a non-DFAULT option;
c. Removal of the TOXICS option from the MODELOPT key word. Options
formerly associated with the TOXICS option are still considered non-DFAULT
options within AERMOD. The area source optimizations formerly associated
with the TOXICS option are now selected using the new non-DFAULT
FASTAREA option on the MODELOPT keyword;
d. A new non-DFAULT option for optimizing runtime for POINT and VOLUME
sources based on an alternative implementation of the horizontal meander
algorithm has been incorporated through the FASTALL option on the
MODELOPT keyword. The FASTALL option also includes the FASTAREA
optimizations if area sources are included in the model inputs;
e. The option for specifying hourly emissions from a separate file through the
HOUREMIS keyword has been enhanced to allow the use of hourly varying
release heights and initial dispersion coefficients for VOLUME and
AREA/AREAPOLY/AREACIRC sources;
f The OPENPIT source option has been modified to allow for use of the
OPENPIT source for gaseous (non-particulate) emissions;
g. A new SUMMFILE option has been included on the OU pathway to output the
summary of high ranked values to a separate file;
h. The non-DFAULT option of FLAT terrain can now be specified on a source-by-
source basis, allowing both FLAT and ELEV terrain treatments within the same
model run (see Section 4.1 of'the AERMOD Implementation Guide regarding
modeling of sources with terrain-following plumes in sloped terrain);
i. A non-DFAULT option for a user-specified dry deposition velocity for gaseous
emissions has been added under the GASDEPVD keyword on the CO pathway;
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j. An option to use scientific notation for output result files has been added
through the FILEFORM keyword on the OU pathway. The FILEFORM option
is applicable to PLOTFILEs, plot-formatted POSTFILEs, MAXIFILEs,
RANKFILEs, and SEASONHR files;
k. An option (WARNCHKD) has been added to the MODELOPT keyword to
allow issuing of warning messages rather than fatal errors for non-sequential
meteorological data files, in order to allow use of multi-year meteorological
data files that may contain gaps between years of data under the DF AULT
option; and
1. The maximum length of filenames specified in the 'aermod.inp' file has been
increased to 200 (controlled by the ILEN_FLD parameter in modules.f), and the
maximum input string length to 512 (controlled by the ISTRG parameter in
modules.f). Double quotes (") are also allowed as field delimiters in the
'aermod.inp' file to support filenames with embedded spaces.
1.2 BACKGROUND ON DEPOSITION ALGORITHMS
The deposition algorithms incorporated into AERMOD are based on the draft Argonne
National Laboratory (ANL) report (Wesely et al., 2002), with modifications based on peer
review. Treatment of wet deposition was revised from Wesely et al. (2002) based on
recommendations by peer review panel members (Walcek et al., 2001). A full technical
description of the deposition algorithms implemented in AERMOD is provided in an EPA report
(EPA, 2003).
The deposition algorithms based on the ANL report were initially implemented in the
AERMOD model under the non-DFAULT TOXICS option, which was selected by including the
TOXICS keyword on the CO MODELOPT card. Beginning with version 09260 of AERMOD,
the TOXICS option has been removed from the model. Those options in AERMOD that were
formerly associated with the TOXICS option are still considered non-DFAULT options but no
longer require the specification of the TOXICS option to allow their use. The other changes to
the AERMOD model inputs associated with the deposition algorithms are limited to the CO
(control) pathway and the SO (source) pathway. For gaseous dry deposition based on the ANL
algorithms, the user must define the seasonal categories based on the ANL report for each of the
calendar months, and must also define the land use category and three pollutant-specific physical
parameters that are provided in the appendices of the ANL report. An optional keyword is also
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provided to override default values for three parameters used in the gas deposition algorithm.
The input requirements for "Method 1" particle deposition in AERMOD are the same as for the
particle deposition algorithm in the ISCST3 model and are described below in Section 2.2. For
"Method 2" particle deposition, the user must define the fraction of the particle mass in the fine
particle category (less than 2.5 microns) and a representative mass mean diameter for the
particles, which are also provided for selected pollutants in Appendix B of the ANL report. The
keywords used to define these inputs and the meteorological data requirements for deposition are
described in Section 2.2.
Consistent with Section 7.2.7(b) of the Guideline on Air Quality Models (40 CFR Part
51, Appendix W), the use of "Method 1" for particle deposition in AERMOD is allowed under
the regulatory DFAULT option. However, use of the "Method 1" particle deposition algorithms
require quantification of the particle size distribution and should be done in coordination with
the appropriate reviewing authority. Use of the "Method 2" option for particle deposition and
the gas deposition algorithms (both dry and wet) are considered non-DFAULT options in
AERMOD. Table 1-1 summarizes the required keywords for the various deposition options
within AERMOD and whether they are allowed under the DFAULT option.
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Table 1-1. Summary of Deposition Options in AERMOD
Pollutant Type
Gaseous
Gaseous
Gaseous
Particulate
("Method 1")
Particulate
("Method 2")
Model Output Type
CONC w/dry depletion
DDEP
CONC w/wet depletion
WDEP
CONC w/dry & wet
depletion
DEPOS
CONC w/dry and/or wet
depletion
DEPOS
DDEP
WDEP
CONC w/dry and/or wet
depletion
DEPOS
DDEP
WDEP
Required Keywords
CO GASDEPVD
or
CO GDSEASON,
CO GDLANUSE, and
SO GASDEPOS
SO GASDEPOS
CO GDSEASON,
CO GDLANUSE, and
SO GASDEPOS
SO PARTDIAM,
SO PARTDENS, and
SO MASSFRAX
SO METHOD 2
Allowed under DFAULT?
No
No
No
Yes
No
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2.0 USER INSTRUCTIONS
2.1 DISPERSION MODELING OPTIONS
2.1.1 MODELOPT Keyword
The dispersion options are controlled by the MODELOPT keyword on the CO pathway.
The syntax, type, and order of the MODELOPT keyword are summarized below:
Syntax:
CO MODELOPT
Type:
Order:
DFAULT BETA CONG AREADPLT FLAT NOSTD NOCHKD NOWARN SCREEN
DEPOS and/or or
DDEP ELEV WARNCHKD
and/or
WDEP
DRYDPLT WETDPLT
or or
NODRYDPLT NOWETDPLT
Mandatory, Non-repeatable
Must precede POLLUTID, HALFLIFE and DCAYCOEF
SCIM PVMRM PSDCREDIT FASTALL
or or
OLM FAS TARE A
where:
DFAULT-
BETA-
CONC-
DEPOS-
DDEP-
WDEP-
Specifies that the regulatory default options will be used; note that
specification of the DFAULT option will override some non-DFAULT
options that may be specified in the input file, while other non-
DFAULT options will cause fatal errors when DFAULT is specified
(see below for details);
Non-DFAULT option that allows for draft, "Beta" test options to be
used; currently includes the PSDCPxEDIT option and options for
capped and horizontal stack releases (see Section 2.1.2 for more
details);
Specifies that concentration values will be calculated;
Specifies that total deposition flux values (both dry and wet) will be
calculated;
Specifies that dry deposition flux values will be calculated;
Specifies that wet deposition flux values will be calculated;
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AREADPLT -
FLAT-
ELEV-
NOSTD -
NOCHKD-
WARNCHKD-
NOWARN-
SCREEN -
SCIM-
PVMRM-
OLM-
PSDCREDIT -
Specifies that a non-DFAULT method for optimized plume depletion
due to dry removal mechanisms will be included in calculations for
area sources;
Specifies that the non-DFAULT option of assuming flat terrain will be
used; Note that FLAT and ELEV may be specified in the same model
run to allow specifying the non-DFAULT FLAT terrain option on a
source-by-source basis;
Specifies that the default option of assuming elevated terrain will be
used; Note that FLAT and ELEV may be specified in the same model
run to allow specifying the non-DFAULT FLAT terrain option on a
source-by-source basis;
Specifies that the non-DFAULT option of no stack-tip downwash will
be used;
Specifies that the non-DFAULT option of suspending date checking
will be used for non-sequential meteorological data files;
Specifies that the option of issuing warning messages rather than fatal
errors will be used for non-sequential meteorological data files;
Specifies that the option of suppressing the detailed listing of warning
messages in the main output file will be used (the number of warning
messages is still reported, and warning messages are still included in
the error file controlled by the CO ERRORFIL keyword);
Specifies that the non-DFAULT option for running AERMOD in a
screening mode will be used;
Sampled Chronological Input Model - used only with the ANNUAL
average option to reduce runtime by sampling meteorology at a user-
specified regular interval; SCEVI sampling parameters must be
specified on the ME pathway;
Specifies that the non-DFAULT Plume Volume Molar Ratio Method
(PVMRM) for NC>2 conversion will be used;
Specifies that the non-DFAULT Ozone Limiting Method (OLM) for
NO2 conversion will be used;
Specifies that the non-DFAULT BETA test option will be used to
calculate the increment consumption with PSD credits using the
PVMRM option;
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FASTALL - Non-DFAULT option to optimize model runtime through use of
alternative implementation of horizontal meander for POINT and
VOLUME sources; also optimizes model runtime for AREA/
AREAPOLY/AREACIRC and OPENPIT sources through hybrid
approach (formerly associated with TOXICS option, now controlled
by FASTAREA option);
FASTAREA - Non-DFAULT option to optimize model runtime through hybrid
approach for AREA/ AREAPOLY/AREACIRC and OPENPIT
sources (formerly associated with TOXICS option);
DRYDPLT - Option to incorporate dry depletion (removal) processes associated
with dry deposition algorithms; this requires specification of dry
deposition source parameters and additional meteorological variables;
dry depletion will be used by default if dry deposition algorithms are
invoked;
NODRYDPLT - Option to disable dry depletion (removal) processes associated with
dry deposition algorithms;
WETDPLT - Option to incorporate wet depletion (removal) processes associated
with wet deposition algorithms; this requires specification of wet
deposition source parameters and additional meteorological variables;
wet depletion will be used by default if wet deposition algorithms are
invoked; and
NOWETDPLT - Option to disable wet depletion (removal) processes associated with
wet deposition algorithms.
The DFAULT option has been modified beginning with version 09260 to impose a restriction on
the optional urban roughness length parameter to be 1 meter for regulatory default applications.
The user may select any or all of the output types (CONC, DEPOS, DDEP and/or
WDEP) to be generated in a single model run. The order of these secondary keywords on the
MODELOPT card has no effect on the order of results in the output files - the outputs will
always be listed in the order of CONC, DEPOS, DDEP, and WDEP. Appropriate deposition
parameters must be specified in order to output deposition fluxes using the DEPOS, DDEP,
and/or WDEP keywords (see Sections 1.2 and 2.2 for more details).
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Beginning with version 04300, the dry and/or wet removal (depletion) mechanisms (the
DRYDPLT and WETDPLT options in earlier versions of AERMOD) will automatically be
included in the calculated concentrations or deposition flux values if the dry and/or wet
deposition processes are considered, unless the user specifies the NODRYDPLT and/or
NOWETDPLT options. Note that dry and wet removal effects on calculated concentration
values can be included even if deposition flux values are not being calculated. However, the
additional data requirements for dry and wet deposition, described in Section 2.2, must be met in
order for dry and wet removal to be included in the concentration calculations. The use of the
NODRYDPLT and/or NOWETDPLT options will result in a more conservative estimate of
concentrations and/or deposition fluxes for applications involving deposition processes, but the
degree of additional conservatism will vary depending on the source characteristics,
meteorological conditions, receptor locations and terrain influences. However, the inclusion of
particle deposition effects may increase ground-level concentrations for some sources compared
to the same source modeled as a gaseous emission, due to the effect of gravitational settling on
the particulate plume. The magnitude of this effect will depend on the source characteristics
(elevated or low-level) and particle size distribution.
The PVMRM and OLM options for modeling NO2 conversion are non-DFAULT options,
and only one of these options can be specified for a given model run. Both options require that
the pollutant ID be specified as 'NO2' on the CO POLLUTE) card (see Section 3.2.5 of the
AERMOD User's Guide). These options have additional input requirements as described in
Section 2.4.
Beginning with version 09260, the TOXICS option in no longer used in AERMOD and
the FASTAREA option on the MODELOPT is now used to select the non-DFAULT option to
optimize model runtime for AREA sources (including AREA, AREAPOLY, AREACIRC and
OPENPIT source types). When the FASTAREA option is specified, the area source integration
routine is optimized to reduce model runtime by incorporation of a three-tiered approach using
the Romberg numerical integration, a 2-point Gaussian Quadrature routine for numerical
integration, or a point source approximation, depending on the location of the receptor relative to
the source. In the regulatory default mode the Romberg numerical integration is utilized for all
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receptors. Also beginning with version 09260, a non-DFAULT option to optimize model
runtime for POINT and VOLUME sources has been included, which is selected by the
FASTALL option on the MODELOPT keyword. Specification of the FASTALL option also
activates the FASTAREA option if AREA sources are including in the model inputs. Both
FASTALL and FASTAREA skip receptors that are more than 80 kilometers from the source.
The FASTALL option for POINT and VOLUME sources uses an alternative
implementation of the horizontal meander algorithm based on an effective horizontal dispersion
coefficient (oyeff) that replicates the centerline concentration based on the full meander approach.
Use of the effective oy allows the model runtime to be optimized by skipping receptors that are
more than 4ayeff off the plume centerline. Based on tests conducted to date, comparisons of
concentrations based on the FASTALL option for POINT and VOLUME sources with
concentrations based on the DFAULT option are similar to comparisons of concentrations for
AREA sources using the FASTAREA option. The average ratio of FASTALL concentrations to
DFAULT values is about 1.02 for high ranked values, showing a slight bias toward
overprediction for the FASTALL option. However, the range of ratios for high ranked values
shows both overpredictions and underpredictions relative the DFAULT option, and differences
at specific receptors may be much larger.
2.1.2 BETA Test Options
A 'BETA' test option switch is included on the CO MODELOPT keyword to identify and
allow for new features to be added to the model that are still in a draft BETA-test status. The
BETA option is a non-DFAULT option, and will result in a fatal error if the DFAULT option is
also specified. Two draft enhancements are included in AERMOD under the BETA option,
beginning with version 06341:
1) Options for capped stacks (source type = POINTCAP) and for horizontal releases
(source type = POINTHOR); and
2) The PSDCREDIT option for PVMRM to account for NO/NO2 chemistry of combined
plumes in the computation of increment consumption with PSD credits.
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Inclusion of these draft BETA-test options does not imply any endorsement of their use for
regulatory or non-regulatory applications of the model. In addition, the designation of BETA-test
to these draft enhancements does not imply that these options have completed rigorous internal
("Alpha") testing prior to being included in a public release of the model.
2.1.3 Processing for Particulate Matter (PM) NAAQS
2.1.3.1 Processing for Fine Particulate Matter (PM-2.5)
A NAAQS for fine particulate matter, with aerodynamic particle diameters of 2.5
microns or less (PM-2.5), was promulgated in 1997, and the 24-hour standard was revised in
December 2006. For attainment demonstrations, the PM-2.5 standard is based on a 3-year
average of the 98th percentile 24-hour average and a 3-year average of the annual mean at each
ambient monitor. For purposes of modeling demonstrations of compliance with the NAAQS, the
eighth-highest value is an unbiased surrogate for the 98th percentile 24-hour average
concentration at a particular receptor over a one-year period. Since the Guideline on Air Quality
Models (40 CFR Part 51, Appendix W) prescribes the use of a 5-year data set for off-site
National Weather Service (NWS) meteorological data or at least one year of site-specific data, a
policy was established to utilize all available meteorological data (both single and multiple years
of data) as an unbiased estimate of the 3-year averages for purposes of modeling demonstrations
of compliance with the NAAQS.
Based on this policy, the 24-hour design value for purposes of modeling demonstrations
of compliance with the PM-2.5 NAAQS is based on the highest of the eighth-highest (H8H)
concentrations at each receptor, if one year of site-specific meteorological data is input to the
model, or the highest of the multi-year average of the eighth-highest concentrations at each
receptor, if more than one year of meteorological data is input to the model. In other words, the
model calculates the eighth-highest concentration at each receptor for each year modeled,
averages those eighth-highest concentrations at each receptor across the number of years of
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meteorological data, and then selects the highest, across all receptors, of the N-year averaged
eighth-highest values.
Similar to the 24-hour averages, an unbiased estimate of the 3-year average annual mean
is simply the annual mean, if only one year of site-specific meteorological data is input to the
model, or the multi-year average of the annual means if multiple years of meteorological data are
used. The annual design value for PM-2.5 is then based on the highest annual average across the
receptor domain for single-year meteorological data input, or the highest of the multi-year
averaged annual means across the receptor domain for multi-year meteorological data input.
The special processing of the 24-hour and annual averages for the PM-2.5 NAAQS is
triggered by specifying a pollutant ID of 'PM25' or 'PM-2.5' on the CO POLLUTE) card. In this
case, the model will compute the 24-hour and annual average design values as described in the
previous paragraphs. In order for the PM-2.5 processing to work correctly for multiple year
periods, the yearly meteorological data files must be concatenated into a single multi-year file
for input into the model. Multi-year meteorological data files can also be generated by
processing multi-year inputs in AERMET, the meteorological processor for AERMOD. There is
no requirement to remove the header records between concatenated surface meteorological data
files prior to running the model. Processing the average of the individual annual mean values
across multiple years for PM-2.5 also requires use of the ANNUAL average option on the
AVERTEVIE keyword, rather than PERIOD average. The PERIOD option computes a single
multi-year average concentration for each receptor, which may give slightly different results than
the multi-year average of individual ANNUAL mean concentrations due to differences in the
number of calms and/or missing data from year to year.
In order to comply with these processing requirements, the following restrictions
which are applied to the PM-2.5 NAAQS processing whenever a pollutant ID of 'PM25' or
'PM-2.5' is specified:
1. The averaging periods on the AVERTIME keyword are limited to the 24-hour and
ANNUAL averages. Use of the PERIOD average or use of a short-term average other
than 24-hour will result in a fatal error message being generated.
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2. Only the EIGHTH (or 8TH) highest value may be requested on the RECTABLE keyword for
24-hour averages. Specifying another high value on the RECTABLE card will result in a
fatal error message being generated.
3. The model will only process meteorological data for periods of record that span complete
years, although the meteorological data period does not need to follow calendar years
(i.e., the data period does not need to start on January 1, hour 1). If the period of record
spans less than one complete year of data, a fatal error message will be generated and the
model run will be unsuccessful. If additional meteorological data remains after the end of
the last complete year of data, the remaining data will be ignored, and a non-fatal warning
message will be generated specifying the number of hours ignored.
4. The MULTYEAR card on the CO pathway cannot be used to calculate multi-year
averages for the PM-2.5 NAAQS. Multiple year analyses must be accomplished by
including the multiple years of meteorology in a single data file.
5. Since the 24-hour average design values for PM-2.5 analyses, based on the H8H
averaged over N years, may consist of averages over a multi-year period, they are
incompatible with the EVENT processor. If the MAXIFILE option is used to output 24-
hour average threshold violations, these may be used with the EVENT processor.
Therefore, if the EVENTFIL option is used without the MAXIFILE option for PM-2.5
analyses, a non-fatal warning message will be generated, and the EVENTFIL option
will be ignored.
2.1.3.2 Processing for Particulate Matter of 10 Microns or Less (PM-10)
The 24-hour NAAQS for parti culate matter with aerodynamic particle diameters of 10
microns or less (PM-10) is in the form of an expected exceedance value, which cannot be
exceeded more than once per year on average over a three year period for purposes of
attainment demonstrations. Modeling demonstrations of compliance with the PM-10 NAAQS
are based on the High-N+1-High value over N years, or in the case of five years of NWS
meteorological data, the High-6th-High (H6H) over five years. In the AERMOD model, the
H6H 24-hour average over five years can be modeled in one of two ways: 1) running five
individual years and combining the results using the CO MULTYEAR option, as described in
Section 3.2.12 of the AERMOD User's Guide; or 2) using a single five-year meteorological data
file and specifying the SIXTH (or 6TH) highest value on the OU RECTABLE card. If applied
properly, the results of these two approaches will be equivalent. The special processing
consisting of the 99th percentile 24-hour value averaged over N years for PM-10 in previous
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versions of AERMOD, referred to as the "Post-1997" PM-10 option, has been removed since
that standard was vacated.
2.1.4 Specifying Multiple Urban Areas
The AERMOD model (beginning with the version dated 06341) includes the option to
specify multiple urban areas within the same model run. This option may be applicable for large
domains that encompass more than one identifiable urban area where the separation is large
enough to warrant separate treatment of the urban boundary layer effects. Use of the option for
multiple urban areas eliminates the need for post-processing for such applications. The multiple
urban areas are defined using multiple CO URBANOPT cards. The syntax of the modified
URBANOPT keyword is as follows:
Syntax: For Multiple Urban Areas:
CO URBANOPT UrbanID UrbPop (UrbName) (UrbRoughness)
For Single Urban Areas:
CO URBANOPT UrbPop (UrbName) (UrbRoughness)
Type: Optional, Repeatable for multiple urban areas
where the UrbanID parameter is the alphanumeric urban ID defined by the user (up to eight
characters) when multiple urban areas are defined, the UrbPop parameter specifies the
population of the urban area, the optional UrbName parameter may be used to identify the name
of the urban area, and the optional UrbRoughness parameter may be used to specify the urban
surface roughness length. Note the UrbName must be specified if the user wants to specify the
urban roughness length. A default value of 1.0 meter will be used for the urban roughness length
if the UrbRoughness parameter is omitted. Beginning with version 09260, any value for the
urban roughness length other than 1.0 meter will be treated as a non-DFAULT option. Caution
should be used when specifying a non-default urban roughness length, and use of a non-default
value should be clearly documented and justified. Note that the syntax of the URBANOPT
keyword for single urban areas has not changed from the previous version of AERMOD, so that
existing input files will not require modification.
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The syntax of the URBANSRC keyword on the SO pathway has also been modified to
allow for the option of specifying multiple urban areas. The syntax of the modified
URBANSRC keyword is as follows:
Syntax: For Multiple Urban Areas:
SO URBANSRC UrbanID SrcID's and/or SrcRng's
For Single Urban Areas:
SO URBANSRC SrcID's and/or SrcRng's
Type:
Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the UrbanID parameter is the alphanumeric urban ID (up to eight characters) defined by
the user on the CO URBANOPT keyword when multiple urban areas are defined, and the
SrcID's and SrcRng's are the individual source IDs and/or source ID ranges that are to be
modeled with urban effects. Source ranges are described in more detail in Section 3.3.3 of the
AERMOD User's Guide (EPA, 2004a). As with the URB ANOPT keyword, the syntax of the
URBANSRC keyword for applications with single urban areas has not changed from the
previous version of AERMOD, so that existing input files will not require modification.
2.1.5 BETA Options for Capped and Horizontal Stack Releases
Draft BETA test options are included in AERMOD (beginning with the version dated
06341) for modeling releases from capped and horizontal stacks. For sources that are not subject
to building downwash influences, the plume rise for these capped and horizontal stacks is
simulated based on an EPA Model Clearinghouse Memorandum, dated July 9, 1993, included in
Appendix A of this Addendum. The Model Clearinghouse procedure for these sources entails
setting the exit velocity very low (0.001 m/s) to account for suppression of vertical momentum
for the plume, and using an effective stack diameter that maintains the actual flow rate of the
plume. Maintaining the flow rate will also serve to maintain the buoyancy of the plume in order
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to provide a more realistic estimate of plume rise. The Model Clearinghouse procedure also
addresses the issue of stack-tip downwash for these cases.
The Model Clearinghouse procedure is not considered appropriate for sources subject to
building downwash influences with the PRIME downwash algorithm for the following reason.
The PRIME algorithm uses the specified stack diameter to define the initial radius of the plume
for the numerical plume rise calculation; use of an effective diameter adjusted to maintain flow
rate is not appropriate and could produce unrealistic results. For PRIME downwash sources
modeled using the BETA options for capped and horizontal releases, the basic premise of the
Model Clearinghouse procedure, i.e. that the vertical momentum is suppressed while the
buoyancy of the plume is conserved, have been adapted for the PRIME numerical plume rise
formulation. However, this adaptation of the Model Clearinghouse procedure to PRIME
downwash sources has not been validated by field tracer or wind tunnel data.
The user selects the BETA options for capped and/or horizontal releases by specifying
one of the new source types on the SO LOCATION card: POINTCAP for capped stacks, and
POINTHOR for horizontal releases. For each of these options, the user specifies the actual stack
parameters [release height (m), exit temperature (K), exit velocity (m/s), and stack diameter (m)]
using the SO SRCPARAM card as if the release were a non-capped vertical point source. The
syntax of the SO LOCATION and SRCPARAM keywords is described in Sections 3.3.1 and
3.3.2, respectively, of the AERMOD User's Guide (EPA, 2004a). The AERMOD model
performs the necessary adjustments internally to account for plume rise and stack-tip downwash.
For horizontal releases, the model currently assumes that the release is oriented with the wind
direction, and the model does not account for directional effects that may occur with horizontal
releases. The model also does not account for stacks oriented at a non-horizontal angle relative
to vertical. For PREVIE-downwashed sources, the user-specified exit velocity for horizontal
releases is treated initially as horizontal momentum in the downwind direction. More details
regarding the BETA options for capped and horizontal releases will be provided later, as
warranted based on further testing and evaluation.
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2.2 DEPOSITION ALGORITHM INPUTS AND OPTIONS
The AERMOD model includes algorithms for both dry and wet deposition of both
particulate and gaseous emissions. Based on the guidance provided for application of the
AERMOD model in Appendix W, and based on the history of deposition algorithms in the
AERMOD and ISC models, the particle deposition algorithms with a user-specified particle size
distribution (referred to below as "Method 1") can be applied under the regulatory default
option. This option is comparable to the particle deposition algorithm in the ISCST3 model
(EPA, 1995a). The gas deposition algorithms and the "Method 2" option for particle deposition
based on the ANL draft report (Wesely, et al, 2002) are considered to be non-DFAULT options
in AERMOD, and the model will issue a fatal error message and abort processing if the
DFAULT option is specified with the gas deposition or Method 2 particle deposition options. As
discussed above in Section 1.2, the TOXICS option formerly associated with the options for gas
deposition and Method 2 for particle deposition is no longer used in the AERMOD model. No
additional option switches are required to allow use of these non-DFAULT options. Table 1-1 in
Section 1.2 summarizes the required keywords and regulatory status of various deposition
options within AERMOD. The remainder of this section provides a detailed description of the
model input parameters associated with the deposition algorithms.
2.2.1 Definition of Seasons for Gas Dry Deposition
The gas deposition algorithms in AERMOD include land use characteristics and some
gas deposition resistance terms based on five seasonal categories, defined in Table 2 of the ANL
report as:
Seasonal Category 1: Midsummer with lush vegetation
Seasonal Category 2: Autumn with unharvested cropland
Seasonal Category 3: Late autumn after frost and harvest, or winter with no snow
Seasonal Category 4: Winter with snow on ground (with generally continuous snow
cover)
Seasonal Category 5: Transitional spring with partial green coverage or short annuals
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The user correlates these seasonal definitions to calendar months through the GDSEASON
keyword on the CO pathway. The syntax and type of the GDSEASON keyword are:
Syntax: CO GDSEASON Jan Feb Mar ... Dec
Type: Optional, Non-repeatable
where a numeric value from 1 to 5 is entered for each of the twelve calendar months to associate
it with the seasonal definitions given above. This keyword is optional for the model, but
mandatory when applying the gas deposition algorithms, unless the GASDEPVD option for user-
specified dry deposition velocity on the CO pathway is used, described below in Section 2.2.5.
Note that some of the seasonal categories defined above may not apply for certain regions, such
as Category 4, winter with continuous snow cover, for moderate climates.
2.2.2 Definition of Land Use Categories for Gas Dry Deposition
The gas deposition algorithms include some gas deposition resistance terms based on five
seasonal categories, defined above, and nine land use categories as follows (from Table 1 of the
ANL report):
Land Use Category Description
1 Urban land, no vegetation
2 Agricultural land
3 Rangeland
4 Forest
5 Suburban areas, grassy
6 Suburban areas, forested
7 Bodies of water
8 Barren land, mostly desert
9 Non-forested wetlands
The user defines the land use categories by direction sector through the GDLANUSE keyword
on the CO pathway. The syntax and type of the GDLANUSE keyword are:
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Syntax: CO GDLANUSE Seel Sec2 Sec3 ... Sec36
Type: Optional, Non-repeatable
where a numeric value from 1 to 9 is entered for each of the 36 direction sectors (every 10
degrees) to associate it with the land use definitions given above. This keyword is optional for
the model, but mandatory when applying the gas deposition algorithms, unless the GASDEPVD
option for user-specified deposition velocity is used. The first value, Seel, corresponds with the
land use category, downwind of the application site, for winds blowing toward 10 degrees, plus
or minus 5 degrees. The downwind sectors are defined in clockwise order, with Sec36
corresponding to winds blowing toward 360 degrees (North), and should generally reflect
conditions downwind relative to the source location. The user can specify "repeat values" by
entering a field such as "36*3" as a parameter for the GDLANUSE keyword. The model will
interpret this as "36 separate entries, each with a value of 3." Since the model must identify this
as a single parameter field, there must not be any spaces between the repeat-value and the value
to be repeated.
2.2.3 Option for Overriding Default Parameters for Gas Dry Deposition
An optional keyword is available on the Control (CO) pathway to allow the user to
override the default values of the reactivity factor (f0\ and the fraction (F) of maximum green
leaf area index (LAI) for seasonal categories 2 (autumn/unharvested cropland) and 5 (transitional
spring), for use with the gas dry deposition algorithms.
The syntax and type of the GASDEPDF keyword are summarized below:
Syntax: CO GASDEPDF React F_Seas2 F_Seas5 (Refpoll)
Type: Optional, Non-repeatable
where the parameter React is the value for pollutant reactivity factor (f0), and F_Seas2 and
F_Seas5 are the fractions (F) of maximum green LAI for seasonal categories 2 and 5,
respectively. The parameter Refpoll is the optional name of the pollutant. If the optional
GASDEPDF keyword is omitted, then the default value of 0 is used for React, and default values
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of 0.5 and 0.25 are used for F_Seas2 and F_Seas5, respectively. A value of F=1.0 is used for
seasonal categories 1, 3, and 4. A reactivity factor value of 1 should be input for ozone (O3),
titanium tetrachloride (TiCU), and divalent mercury (Hg2+), and a value of 0.1 should be input
for nitrogen dioxide (NC^).
2.2.4 Specifying Source Parameters for Gas Deposition (Dry and/or Wet)
The input of source parameters for dry and wet deposition of gaseous pollutants is
controlled by the GASDEPOS keyword on the SO pathway. The gas deposition variables may
be input for a single source, or may be applied to a range of sources.
The syntax, type, and order for the GASDEPOS keyword are summarized below:
Syntax: SO GASDEPOS Srcid (or Srcrng) Da Dw rcl Henry
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the Srcid or Srcrng identify the source or sources for which the inputs apply, the
parameter Da is the diffusivity in air for the pollutant being modeled (cm2/s), Dw is the
diffusivity in water for the pollutant being modeled (cm2/s), rcl is the cuticular resistance to
uptake by lipids for individual leaves (s/cm), and Henry is the Henry's Law constant (Pa
m3/mol). Values of the physical parameters for several common pollutants may be found in the
appendices to the ANL report (Wesely, et. al, 2002).
2.2.5 Option for Specifying the Deposition Velocity for Gas Dry Deposition
An optional keyword is available on the Control (CO) pathway to allow the user to
specify the dry deposition velocity for gaseous emissions. A single dry deposition velocity can
be input for a given model run, and is used for all sources of gaseous pollutants. Selection of
this option will by-pass the algorithm for computing deposition velocities for gaseous pollutants,
and should only be used when sufficient data to run the algorithm are not available. Results of
the AERMOD model based on a user-specified deposition velocity should be used with extra
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caution.
The syntax and type of the GASDEPVD keyword are summarized below:
Syntax: CO GASDEPVD Uservd
Type: Optional, Non-repeatable
where the parameter Uservd is the gaseous dry deposition velocity (m/s). A non-fatal warning
message is generated by the model if a value of Uservd greater than 0.05 m/s (5 cm/s) is input by
the user. When the GASDEPVD keyword is used, the GDSEASON, GDLANUSE, and
GASDEPRF keywords for the CO pathway, and the GASDEPOS keyword for the SO pathway,
are no longer applicable and cannot be used in the same model run. As a result, gas wet
deposition processes (DEPOS, WDEP, and WETDPLT) cannot be simulated with the
GASDEPVD option is used.
2.2.6 Specifying Source Parameters for Particle Deposition
The AERMOD model includes two methods for handling dry and/or wet deposition of
particulate emissions. Method 1 is used when a significant fraction (greater than about 10
percent) of the total paniculate mass has a diameter of 10 um or larger, or when the particle size
distribution is known. The particle size distribution must be known reasonably well in order to
use Method 1. Method 2 may be used when the particle size distribution is not well known and
when a small fraction (less than 10 percent of the mass) is in particles with a diameter of 10 um
or larger. The deposition velocity for Method 2 is calculated as the weighted average of the
deposition velocity for particles in the fine mode (i.e., less than 2.5 um in diameter) and the
deposition velocity for the coarse mode (i.e., greater than 2.5 um but less than 10 um in
diameter). As described in Sections 1.2 and 2.2, use of the Method 2 option is considered non-
DFAULT.
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2.2.6.1 Specifying Particle Inputs for Method 1
The input of source variables for particle deposition using Method 1 is controlled by
three keywords on the SO pathway, PARTDIAM, MASSFRAX, and PARTDENS. These inputs
are comparable to the particulate inputs used in the ISCST3 model (EPA,1995a). The particle
variables may be input for a single source, or may be applied to a range of sources.
The syntax, type and order for these three keywords are summarized below:
Syntax: SO PARTDIAM Srcid (or Srcrng) Pdiam(i), i=l,Npd
SO MASSFRAX Srcid (or Srcrng) Phi(i), i=l,Npd
SO PARTDENS Srcid (or Srcrng) Pdens(i), i=l,Npd
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the Srcid or Srcrng identify the source or sources for which the inputs apply, and where
the Pdiam array consists of the mass-mean aerodynamic particle diameter (microns) for each of
the particle size categories, the Phi array is the corresponding mass fractions (between 0 and 1)
for each of the categories, and the Pdens array is the corresponding particle density (g/cm3) for
each of the categories.
The number of particle size categories for a particular source is Npd. The user does not
explicitly tell the model the number of categories being input, but if continuation cards are used
to specify particle size variables, all inputs of a keyword for a particular source or source range
must be contiguous, and the number of categories must agree for each of the three keywords
input for a particular source. As many continuation cards as needed may be used to define the
inputs for a particular keyword. The model checks the inputs to ensure that the mass fractions
sum to 1.0 (within 2 percent) for each source input, and issues a warning message if that range is
exceeded. The model also ensures that mass fractions for each particle size category are within
the proper range (between 0 and 1), and issues fatal error messages for any value exceeded that
range.
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2.2.6.2 Specifying Particle Inputs for Method 2
The Method 2 particle information is input through the METHOD_2 keyword on the SO
pathway. The syntax, type, and order for the METHOD_2 keyword are summarized below:
Syntax: SO METHOD_2 Srcid (or Srcrng) FineMassFraction Dmm
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the Srcid or Srcrng identify the source or sources for which the inputs apply, the
parameter FineMassFraction is the fraction of particle mass emitted in the fine mode, less than
2.5 microns, and Dmm is the representative mass-mean aerodynamic particle diameter in
microns. Estimated values of fine particle fractions and mass mean diameters for various
pollutants are provided in Appendix B of the ANL report (Wesely, et al, 2002).
2.2.7 Specifying Emission and Output Units
Since the AERMOD model allows for both concentration and deposition to be output in
the same model run, the EMISUNIT keyword (see Section 3.3.6 of the AERMOD User's Guide
(EPA, 2004a)) cannot be used to specify emission unit factors if more than one output type is
being generated. The AERMOD model therefore allows for concentration and deposition units
to be specified separately through the CONCUNIT and DEPOUNIT keywords, respectively.
The syntax and type of the CONCUNIT keyword are summarized below:
Syntax: SO CONCUNIT Emifac Emilbl Conlbl
Type: Optional, Non-repeatable
where the parameter Emifac is the factor to convert emission rate input units to the desired
output units, Emilbl is the label for the emission input units (up to 40 characters), and Conlbl is
the output unit label (up to 40 characters) for concentration calculations. The syntax and type of
the DEPOUNIT keyword are summarized below:
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Syntax: SO DEPOUNIT Emifac Emilbl Deplbl
Type: Optional, Non-repeatable
where the parameter Emifac is the factor to convert emission rate input units to the desired
output units, Emilbl is the label for the emission input units (up to 40 characters), and Deplbl is
the output unit label (up to 40 characters) for deposition calculations.
2.2.8 Deposition Velocity and Resistance Outputs
In order to facilitate review and testing of the deposition algorithms in the AERMOD
model, the model includes an option to output the main resistance terms and deposition
velocities for gaseous and particle sources. These optional outputs are generated if the user
specifies the 'CO DEBUGOPT MODEL' option described in Section 3.2.12 of the AERMOD
User's Guide (EPA, 2004a). The gas deposition data are written to a file called GDEP.DAT,
which includes the values of Ra, Rb, Rc, and Vdg (see Wesely, et al, 2002, for definitions) for each
source and for each hour modeled. A header record is included to identify the columns. The
particle deposition data are written to a file called PDEP.DAT, which includes the values of Ra,
Rp, Vg, and Vd for each source and for each hour modeled. The particle outputs are labeled as
being based on either Method 1 or Method 2. For Method 1, results are output for each particle
size category. The filename and file units for these data files are hardcoded in the model, and the
files are overwritten each time the model is executed. Since these files include data for each
source for each hour, file sizes may become large.
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2.2.9 Meteorological Data for Deposition Algorithms
The AERMET meteorological processor was modified (beginning with the version dated
04300) to output additional meteorological parameters needed for the deposition algorithms in
AERMOD. The additional variables include the precipitation code, precipitation rate, relative
humidity, surface pressure, and cloud cover. These additional variables are automatically
included after the standard variables for each hour, and do not require any additional user input.
The precipitation data needed for wet deposition calculations in AERMOD can be obtained from
the SAMSON, HUSWO or ISHD (TD-3505) formats currently supported by AERMET (EPA,
2004b).
The input meteorological data file consists of a header record that includes the latitude
and longitude, surface station ID (e.g., WBAN number), upper air station ID, the on-site station
ID, and the AERMET version date (see Section D.I of the AERMOD model user's guide (EPA,
2004a)). The meteorological data file for the deposition algorithms is read as a free format file,
i.e., each field on a record is separated from adjacent fields by a comma or by one or more
spaces. The subsequent data records contain the following variables in the order listed:
Variable Description Format
Year Integer
Month Integer
Day of Month Integer
Julian Day (Day of Year) Integer
Hour of Day Integer
Heat Flux (W/m2) Real
Surface Friction Velocity, u* (m/s) Real
Convective Velocity Scale, w* (m/s) Real
Lapse Rate Above Mixing Height (K/m) Real
Convective Mixing Height (m) Real
Mechanical Mixing Height (m) Real
Monin-Obukhov Length, L (m) Real
Surface Roughness Length, z0 (m) Real
Bowen Ratio Real
Albedo Real
Reference Wind Speed (m/s) Real
Reference Wind Direction (degrees) Real
Reference Height for Wind (m) Real
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Ambient Temperature (K) Real
Reference Height for Temperature (m) Real
Precipitation Code (0-45) Integer
Precipitation Amount (mm) Real
Relative Humidity (%) Real
Surface Pressure (mb) Real
Cloud Cover (tenths) Integer
2.3 OPEN PIT SOURCE OPTION
The open pit source option is invoked by specifying a source type of OPENPIT on the
source location (SO LOCATION) card. The OPENPIT source algorithm can be used to model
particulate or gaseous emissions from open pits, such as surface coal mines and rock quarries. If
particulate emissions modeled, the user must specify the particle size information through the
appropriate keywords described in Section 2.2. The OPENPIT algorithm uses an effective area
for modeling pit emissions, based on meteorological conditions, and then utilizes the numerical
integration area source algorithm to model the impact of emissions from the effective area
sources. A complete technical description of the OPENPIT source algorithm is provided in the
ISC3 Model User's Guide - Volume II (EPA, 1995b).
The AERMOD model accepts rectangular pits with an optional rotation angle specified
relative to a north-south orientation. The rotation angle is specified relative to the vertex used to
define the source location on the SO LOCATION card (e.g., the southwest corner). The syntax,
type and order for the SRCPARAM card for OPENPIT sources are summarized below:
Syntax: SO SRCPARAM Srcid Opemis Relhgt Xinit Yinit Pitvol (Angle)
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the Srcid parameter is the same source ID that was entered on the LOCATION card for a
particular source, and the other parameters are as follows:
Opemis - open pit emission rate in g/(s-m2),
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Relhgt - average release height above the base of the pit in meters,
Xinit - length of X side of the open pit (in the east-west direction if Angle is 0
degrees) in meters,
Yinit - length of Y side of the open pit (in the north-south direction if Angle is 0
degrees) in meters,
Pitvol - volume of open pit in cubic meters, and
Angle - orientation angle for the rectangular open pit in degrees from North, measured
positive in the clockwise direction (optional).
The same emission rate is used for both concentration and deposition calculations in the
AERMOD model. It should also be noted that the emission rate for the open pit source is an
emission rate per unit area, which is different from the point and volume source emission rates,
which are total emissions for the source. The Relhgt parameter cannot exceed the effective
depth of the pit, which is calculated by the model based on the length, width and volume of the
pit. A Relhgt of 0.0 indicates emissions that are released from the base of the pit.
If the optional Angle parameter is input, and the value does not equal 0.0, then the model
will rotate the open pit clockwise around the vertex defined on the SO LOCATION card for this
source. The relationship between the Xinit, Yinit, and Angle parameters and the source location,
(Xs,Ys), for a rotated pit is the same as for rectangular area sources. The Xinit dimension is
measured from the side of the area that is counterclockwise along the perimeter from the vertex
defined by (Xs,Ys), while the Yinit dimension is measured from the side of the open pit that is
clockwise along the perimeter from (Xs,Ys). Unlike the area source inputs, the Yinit parameter
is not optional for open pit sources. The Angle parameter is measured as the orientation relative
to North of the side that is clockwise from (Xs,Ys), i.e. the side with length Yinit. The Angle
parameter may be positive (for clockwise rotation) or negative (for counterclockwise rotation),
and a warning message is generated if the absolute value of Angle is greater than 180 degrees.
The selection of the vertex to use for the source location is not critical, as long as the relationship
described above for the Xinit, Yinit, and Angle parameters is maintained.
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The aspect ratio (i.e., length/width) of open pit sources should be less than 10 to 1.
However, since the pit algorithm generates an effective area for modeling emissions from the pit,
and the size, shape and location of the effective area is a function of wind direction, an open pit
cannot be subdivided into a series of smaller sources. Aspect ratios of greater than 10 to 1 will
be flagged by a warning message in the output file, and processing will continue. Since open pit
sources cannot be subdivided, the user should characterize irregularly-shaped pit areas by a
rectangular shape of equal area. Receptors should not be located within the boundaries of the
pit; concentration and/or deposition at such receptors will be set to zero. Such receptors will be
identified during model setup and will be flagged in the summary of inputs.
An example of a valid SRCPARAM input card for an open pit source is given below:
SOSRCPARAM NORTHPIT 1.15E-4 0.0 150.0 500.0 3.75E+6 30.0
where the source ID is NORTHPIT, the emission rate is 1.15E-4 g/(s-m2), the release height is
0.0 m, the X-dimension is 150.0 m, the Y-dimension is 500.0 m, the pit volume is 3.75E+6 cubic
meters (corresponding to an effective pit depth of about 50 meters) and the orientation angle is
30.0 degrees clockwise from North.
2.4 PVMRM AND OLM OPTIONS FOR MODELING NO2
This section provides a description of the inputs related to the non-DFAULT PVMRM
and OLM options for modeling the conversion of NOX to NO2. A technical description of the
PVMRM algorithm is provided in an Addendum to the AERMOD Model Formulation
Document (Cimorelli, et a/., 2004). Background on the original development of the PVMRM
option is provided by Hanrahan (1999a and 1999b).
The PVMRM and OLM algorithms have been implemented as non-DFAULT options,
which means that the PVMRM and OLM options cannot be used if the DFAULT keyword is
included on the CO MODELOPT card. As described in Section 2.1.1, a BETA-test draft model
option, PSDCREDIT, has been added for use when an application is for increment consumption
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with PSD credits using PVMRM. The special source grouping required for the PSDCREDIT
option is described below in Section 2.4.6.1.
2.4.1 Specifying Ozone Concentrations for PVMRM and OLM Options
The background ozone concentrations can be input as a single value through the
OZONEVAL keyword on the CO pathway, or may be input as hourly values through a separate
data file specified through the OZONEFIL keyword on the CO pathway. The user must specify
either the OZONEVAL or OZONEFIL keywords, or both, in order to use the PVMRM or OLM
options. If both keywords are entered, then the value entered on the OZONEVAL keyword will
be used to substitute for hours with missing ozone data in the ozone data file.
The syntax of the OZONEVAL keyword is as follows:
Syntax: CO OZONEVAL OSValue (OSUnits)
Type: Optional, Non-repeatable
where the OSValue parameter is the background ozone concentration in the units specified by
the optional OSUnits parameter (PPM, PPB, or UG/M3). If the optional OSUnits parameter is
missing, then the model will assume units of micrograms/cubic-meter (UG/M3) for the
background ozone values. If units of PPM or PPB are used, then the model will convert the
concentrations to micrograms/cubic-meter based on the reference ambient temperature and the
base elevation specified on the ME PROFBASE card. The OZONEVAL keyword word is
optional and non-repeatable.
The syntax of the OZONEFIL keyword is as follows:
Syntax: CO OZONEFIL OSFileName (OSUnits) (Format)
Type: Optional, Non-repeatable
where the OSFileName parameter is the filename for the hourly ozone concentration file, the
optional OSUnits parameter specifies the units of the ozone data (PPM, PPB, or UG/M3, with
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UG/M3 as the default), and the optional Format parameter specifies the Fortran FORMAT to
read the ozone data. The OSFileName can be up to 200 characters in length based on the default
parameters in AERMOD. Double quotes (") at the beginning and end of the filename can also
be used as field delimiters to allow filenames with embedded spaces. If the optional Format
parameter is missing, then the model will read the ozone data using a Fortran free format, i.e.,
assuming that commas or spaces separate the data fields. The contents of the ozone data file
must include the year (2-digits), month, day, hour and ozone value in that order (unless specified
differently through the Format parameter). The date sequence in the ozone data file must match
the date sequence in the hourly meteorological data files. As with the OZONEVAL keyword, if
units of PPM or PPB are used, then the model will convert the concentrations to
micrograms/cubic-meter based on the reference ambient temperature and the base elevation
specified on the ME PROFBASE card.
Values of ozone concentrations in the ozone data file that are less than zero or greater
than or equal to 900.0 will be regarded as missing. If a background ozone value has been
specified using the OZONEVAL keyword, then that value will be used to substitute for missing
ozone data from the ozone file. If no OZONEVAL keyword is used, then the model will assume
full conversion for hours with missing ozone data.
2.4.2 Specifying the Ambient Equilibrium NO2/NOx Ratio for PVMRM
The PVMRM option for modeling conversion of NO to NO2 incorporates a default
NO2/NOX ambient equilibrium ratio of 0.90. A NO2/NOX equilibrium ratio other than 0.90 can
be specified through the optional NO2EQUIL keyword on the CO pathway. The syntax of the
NO2EQUIL keyword is as follows:
Syntax: CO NO2EQUIL NO2Equil
Type: Optional, Non-repeatable
where the NO2Equil parameter is the NO2/NOX equilibrium ratio and must be between 0.10 and
1.0, inclusive.
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2.4.3 Specifying the Default In-stack NO2/NOx Ratio for PVMRM and OLM
The PVMRM and OLM options for modeling conversion of NO to NO2 require that an
in-stack NO2/NOX ratio be specified. A default value of 0.10 for the in-stack NO2/NOX ratio will
be used for OLM for all sources unless a user-specified value is provided. However, the
PVMRM option requires that the user specify the in-stack NO2/NOX ratio for each source.
The in-stack NO2/NOX ratio can be specified for the PVMRM or OLM options by using
either the CO NO2STACK card to specify a default value to be used for all sources, or by using
the SO NO2RATIO card to specify a value on a source-by-source basis. The SO NO2RATIO
card can also be used to override the default value if the CO NO2STACK card has been
specified. The syntax of the NO2STACK keyword is as follows:
Syntax: CO NO2STACK NO2Ratio
Type: Optional, Non-repeatable
where the NO2Ratio parameter is the default in-stack NO2/NOX ratio that will be used, unless
overridden on a source-by-source basis by the SO NO2RATIO card (described below). The
value of NO2Ratio must be between 0.0 and 1.0, inclusive. Users should note that while CO
NO2STACK is an optional keyword, the PVMRM option requires the user to specify an in-stack
NO2/NOX ratio for each source, using either the CO NO2STACK or SO NO2RATIO cards
(described in Section 2.4.4), or both.
2.4.4 Specifying In-stack NO2/NOx Ratios by Source for PVMRM and OLM
The PVMRM and OLM options for modeling NO2 conversion assume a default in-stack
NO2/NOX ratio of 0.10 (or 10 percent). The user can specify in-stack NO2/NOX ratios through
the optional NO2RATIO keyword on the SO pathway. The syntax of the NO2RATIO keyword
is as follows:
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Syntax: SO NO2RATIO SrcID or SrcRange NO2Ratio
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the SrcID or SrcRange identify the source or sources for which the inputs apply, and
where the NO2Ratio parameter specifies the in-stack ratio. In this way, the user can specify a
single in-stack NO2/NOX ratio for a group of stacks. For example, the following input:
SONO2RATIO STACK1-STACK10 0.15
will apply the in-stack ratio of 0.15 to sources with IDs falling within the range STACK1 to
STACK10. Any value specified on the SO NO2RATIO card will override the default ratio, if
any, specified on the CO NO2STACK card. Users should note that while SO NO2RATIO is an
optional keyword, the PVMRM option requires the user to specify an in-stack NO2/NOX ratio for
each source, using either the CO NO2STACK (described in Section 2.4.3) or SO NO2RATIO
cards, or both.
2.4.5 Specifying Combined Plumes for OLM
The OLM option for modeling NO2 conversion includes an option for specifying which
sources are to be modeled as combined plumes. Sources which are not specified for modeling as
combined plumes will be modeled as individual plumes. The selection of individual or
combined plume option for OLM is specified through the OLMGROUP keyword on the SO
pathway. The syntax of the OLMGROUP card is as follows:
Syntax:
Type:
Order:
SO OLMGROUP OLMGrpID SrcID's and/or SrcRange's
Optional, Repeatable
Must follow the LOCATION card for each source input
where OLMGrpID identifies a group to be treated as a combined plume with OLM, and the
SrcID's and/or SrcRange's identify the sources to be included in the OLM group. As with the SO
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SRCGROUP card, individual source IDs and source ranges may be used on the same card, and if
more than one input card is needed to define the sources for a particular OLM group, then
additional cards may be input by repeating the pathway, keyword and OLM group ID. A user
can also specify an OLMGrpID of ALL, which means that OLM will be applied on a combined
plume basis to all sources. However, unlike the SO SRCGROUP card, the results will not be
output for an OLM group unless the same group of sources is also identified on a SRCGROUP
card. Another constraint is that a source cannot be included in more than one OLM group.
If a source is not selected for an OLMGROUP card, then OLM will be applied to that
source as an individual plume. Other than the similarity in syntax, there is no connection in the
model between the groups defined on the OLMGROUP card and groups defined on the
SRCGROUP card. The OLMGROUP card relates to how the results are processed within the
model for the OLM model, and the SRCGROUP card simply controls how source impacts are
grouped in the model outputs.
If the user identifies one or more groups of sources to apply OLM on a combined plume
basis using the OLMGROUP card, the model will still need to calculate the concentration for
individual plumes within the OLM group in order for the model to sum the results for the sources
listed on the SRCGROUP card(s). The individual source concentrations are calculated by
applying the ratio of the combined concentration for the OLM group with and without OLM to
each source within the OLM group.
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2.4.6 Modeling NO2 Increment Credits with PVMRM
NO
Due to the ozone-limiting effects of the PVMRM option, the predicted concentrations of
are not linearly proportional to the emission rate. Therefore, the approach of modeling NC>2
increment consumption with PSD credits through the use of a negative emission rate for credit
sources cannot be used with the PVMRM option. However, the draft PSDCREDIT option
allows modeling PSD increment credits for NC>2 when the PVMRM option is specified. The
PSDCREDIT option is currently implemented as a BETA-test option, and requires that the
PVMRM and BETA options be specified. The PSDCREDIT option utilizes a new PSDGROUP
keyword, described below, to identify which sources consume or expand increment. This option
is not valid if the OLM option is specified, and no comparable option is available for modeling
increment credits with the OLM option. The user should check with the appropriate reviewing
authority for further guidance on modeling increment credits for NO2.
A general discussion of concepts related to modeling increment consumption is provided
below, followed by a description of inputs required to use the BETA-test PSDCREDIT option
for PVMRM.
2.4.6.1 Increment Consuming and Baseline Sources
Increment is the maximum allowable increase in concentration of a pollutant above a
baseline concentration for an area defined under the Prevention of Significant Deterioration
(PSD) regulations. The PSD baseline area can be an entire State or a subregion of a State such as
a county or group of counties. Increment standards exist for three pollutants: SO2 (3-hr, 24-hr,
and annual averages), NO2 (annual average), and PM-10 (24-hr and annual average). Increment
consumption is the additional air quality impact above a baseline concentration.
The baseline concentration is the ambient concentration of the pollutant that existed in
the area at the time of the submittal of the first complete permit application by any source in that
area subject to PSD regulations. A baseline source is any source that existed prior to that first
application and the baseline date is the date of the PSD application. This baseline date is referred
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to as the minor source baseline date in PSD regulations. By definition, baseline sources do not
consume increment. However, any baseline source that retires from service after the baseline
date expands the increment available to new sources. Therefore, a PSD modeling analysis
performed for a new source may need to account for this increment expansion. Such an analysis
may therefore involve identification of three groups of sources: 1) increment-consuming sources;
2) retired (increment-expanding) baseline sources; and 3) existing, non-retired, baseline sources.
2.4.6.2 Calculating Increment Consumption under the PSDCREDIT Option
Calculating increment consumption under the PSDCREDIT option in AERMOD is not a
simple arithmetic exercise involving the three groups of sources defined above. Since the
amount of ozone available in the atmosphere limits the conversion of NO to NO2, interactions of
plumes from the existing and retired baseline sources with those from the increment consuming
sources must be considered as part of the calculation of net increment consumption. Without the
PSDCREDIT option, properly accounting for the potential interaction of plumes among the
different source categories would require post-processing of results from multiple model runs.
Internal "posf'-processing algorithms have been incorporated in AERMOD under the
PSDCREDIT option to account for the apportioning of the three groups of sources to properly
calculate increment consumption from a single model run.
Define the following three source groupings for the discussion that follows:
A = increment-consuming sources;
B = non-retired baseline sources; and
C = retired baseline, increment-expanding sources.
The calculation of the amount of increment consumption by the A sources cannot simply be
estimated by modeling the A sources alone because of the possible interaction of those plumes
with the plumes from B sources. The PVMRM algorithm is designed to account for such plume
interactions and calculate the total NO to NO2 conversion in the combined plumes based on the
amount of ozone available. Therefore, the total increment consumption by the A sources is
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given by the difference between (1) the total future impact of increment consuming sources and
non-retired baseline sources (A+B) and (2) the total current impact (B), which can be expressed
as (A+B) - (B). Here (A+B) represents the value that would be compared against the National
Ambient Air Quality Standard (NAAQS) for NC>2 during PSD review of the A sources.
In a case where some of the baseline sources have been retired from service (C sources),
the PSD regulations allow the consideration of increment expansion when assessing compliance
with the PSD increment. However, the amount of increment expansion cannot be estimated by
simply modeling the C sources alone because of the possible interaction of those plumes with the
plumes from B sources. Therefore, the total increment expansion, i.e., PSD credit, is calculated
as the difference between (1) the total impact prior to the retirement of C sources, i.e. (B+C),
and (2) the total impact from existing (non-retired) baseline sources (B), which can be expressed
as (B+C) - (B).
Finally, the net increment consumption is given by the difference between total increment
consumption and the total increment expansion, or
[(A+B)-(B)]-[(B+C)-(B)] (1)
Note that in the absence of any increment expansion, the net increment consumption is equal to
the total increment consumption [(A+B) - (B)], as described above.
These expressions of net increment consumption and expansion cannot be interpreted as
algebraic equations. Instead, the terms within parentheses represent the results of separate model
runs that account for the combined effects of NOX conversion chemistry on specific groups of
sources. The expression shown in Equation 1 above represents four model simulations: (A+B),
(B), (B+C), and (B) again. In this case, the two (B) terms do cancel each other and we are left
with:
[(A+B)] - [(B+C)] (2)
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The expression presented in Equation 2 summarizes how the net increment consumption
calculation is performed under the PSDCREDIT option. Under this option, AERMOD first
models the A and B groups together, then models the B and C groups together, and finally
computes the difference to obtain the desired result, i.e., the value to compare to the PSD
increment standard. In order for AERMOD to perform the special processing associated with
this option, the user must define which sources belong to each of the groupings defined above.
The next section describes how this is accomplished.
2.4.6.3 Specifying Source Groups under the PSDCREDIT Option
The PSDCREDIT option introduces limitations on grouping sources in order to calculate
increment consumption as described in the previous section. A new keyword, PSDGROUP, is
used to group the sources to correctly calculate the increment consumption. The syntax, type,
and order are similar to the regular SRCGROUP keyword and are summarized below:
Syntax: SO PSDGROUP Grpid Srcid's and/or Srcrng's
Type: Mandatory for PSDCREDIT option, Repeatable
Order: Must follow the last keyword in the SO pathway before FINISHED
If the PSDCREDIT model option is specified, the PSDGROUP keyword must be used. The
SRCGROUP keyword cannot be used under the PSDCREDIT option since results from other
groupings beyond these three do not have any meaning when the PSDCREDIT option is invoked
and sources are allocated to the calculation of increment consumption. Special source groups for
outputting model results are defined within AERMOD for the PSDCREDIT option, as described
in the next section.
Only the following special PSD group ID's can be used. Failure to use these group ID's
will result in a fatal error message during setup processing by AERMOD. The group ID's are:
INCRCONS - increment-consuming sources (group A above); these can be new
sources or modifications to existing sources;
NONRBASE - existing, non-retired baseline sources (group B above); and
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RETRBASE - retired (increment-expanding or PSD credit) baseline sources (group C
above).
It is important to note that the source emission inputs for sources included in the RETRBASE
PSD group must be entered as positive numbers, unlike other types of PSD credit modeling
where negative emissions are input to simulate the impact of the credit sources on the increment
calculation. The increment-expanding contribution from RETRBASE sources is accounted for
within the AERMOD model under the PSDCREDIT option.
The group ID's can appear in any order, but these are the only three that can be specified.
If there are no retired baseline sources (i.e., no baseline sources are retired), the keyword
RETRBASE can be omitted. Likewise, if there are no non-retired baseline sources (i.e., all
baseline sources have been retired), the NONRBASE keyword can be omitted. The special
group ID 'ALL' that can be use with the SRCGROUP keyword cannot be used with the
PSDGROUP keyword. As with the SRCGROUP keyword for non-PSDCREDIT applications,
the group ID's are repeatable and they must be the last keyword before FINISHED on the SO
pathway when the PSDCREDIT option is specified.
Source ranges, which are described in more detail in Section 3.3.3 of the AERMOD
User's Guide (EPA, 2004a), are input as two source IDs separated by a dash, e.g., STACK1-
STACK10. Individual source IDs and source ranges may be used on the same card. If more
than one input card is needed to define the sources for a particular group, then additional cards
may be input, repeating the pathway, keyword and group ID. A source can appear in only one of
these source groups, and must be assigned to one of the groups.
The requirements for specifying sources and source groups under the PSDCREDIT
option are summarized below:
• The SRCGROUP keyword cannot be used with the PSDCREDIT option;
• Special PSD group ID's must be used with the PSDGROUP keyword;
• The group ID ALL is not allowed when the PSDCREDIT option is specified;
• A source must appear in one, and only one, of the PSDGROUPs; and
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• Emission rates for increment-expanding (RETRBASE) sources must be entered as
positive values.
2.4.6.4 Model Outputs under the PSDCREDIT Option
Unlike the regular SRCGROUP keyword, the PSDGROUP keyword does not define how
the source impacts are grouped for model output. As described in the previous sections, the
PSDGROUP keyword defines the different categories of sources needed in order to properly
account for NOX conversion chemistry under the PVMRM option.
The model outputs under the PSDCREDIT option in AERMOD are based on
demonstrating compliance with the air quality standards, i.e., the NAAQS and PSD increment
for NO2. As a result, AERMOD uses hardcoded "SRCGROUP" names of 'NAAQS' and
'PSDINC' to label these two types of outputs. The results output under the 'NAAQS' source
group label are based on the calculation of (A+B) as described above in Section 2.4.6.2. The
results reported under the 'PSDINC' source group label are based on the expression presented
above in Equation 2.
2.5 VARIABLE EMISSION RATES
2.5.1 Specifying Variable Emission Factors (EMISFACT)
The AERMOD model provides the option of specifying variable emission rate factors for
individual sources or for groups of sources. The syntax, type and order of the EMISFACT
keyword are summarized below:
Syntax: SO EMISFACT SrcID or SrcRange Qflag Qfact(i), i=l,n
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the SrcID parameter is the same source ID that was entered on the LOCATION card for a
particular source. The user also has the option of using the SrcRange parameter for specifying a
39
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range of sources for which the emission rate factors apply, instead of identifying a single source.
This is accomplished by two source ID character strings separated by a dash, e.g., STACK1-
STACK10. The use of the SrcRange parameter is explained in more detail in the description of
the BUILDHGT keyword (see Section 3.3.3 of the AERMOD User's Guide).
The parameter Qflag is the variable emission rate flag, and must be specified as one of
the following secondary keywords:
SEASON - emission rates vary seasonally (n=4),
MONTH - emission rates vary monthly (n=12),
HROFDY - emission rates vary by hour-of-day (n=24),
WSPEED - emission rates vary by wind speed (n=6),
SEASHR - emission rates vary by season and hour-of-day (n=96),
HRDOW - emission rates vary by hour-of-day, and day-of-week [M-F, Sat, Sun]
(n=72),
FIRDOW7 - emission rates vary by hour-of-day, and the seven days of the week [M,
Tu, W, Th, F, Sat, Sun] (n=168),
SHRDOW - emission rates vary by season, hour-of-day, and day-of-week [M-F, Sat,
Sun] (n=288),
SHRDOW7 - emission rates vary by season, hour-of-day, and the seven days of the
week [M, Tu, W, Th, F, Sat, Sun] (n=672),
MHRDOW - emission rates vary by month, hour-of-day, and day-of-week [M-F, Sat,
Sun] (n=864), and
MHRDOW7 - emission rates vary by month, hour-of-day, and the seven days of the
week [M, Tu, W, Th, F, Sat, Sun] (n=2,016).
The Qfact array is the array of factors, where the number of factors is shown above for
each Qflag option. The seasons are defined in the following order: Winter (Dec., Jan., Feb.),
Spring (Mar., Apr., May), Summer (Jun., Jul., Aug.), and Fall (Sep., Oct., Nov.). The wind speed
categories used with the WSPEED option may be defined using the ME WINDCATS keyword.
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If the WINDCATS keyword is not used, the default wind speed categories are defined by the
upper bound of the first five categories as follows (the sixth category is assumed to have no
upper bound): 1.54, 3.09, 5.14, 8.23, and 10.8 m/s. The EMISFACT card may be repeated as
many times as necessary to input all of the factors, and repeat values may be used for the
numerical inputs. Examples for the more recent HRDOW and MHRDOW options are presented
below, with column headers to indicate the order in which values are to be to input:
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** Weekdays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW 5*0.3 0.5 11*1.0 0.5 6*0.3
** Saturdays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW 5*0.3 0.5 11*1.0 0.5 6*0.3
** Sundays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW I
SO EMISFACT STK1 HRDOW7 enter 24 hourly scalars for each of the "days",
first for Mondays, then for Tuesdays, ..., then for Saturdays,
and finally for Sundays, e.g.,
** Mondays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW7 5*0.3 0.5 11*1.0 0.5 6*0.3
** Tuesdays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW7 5*0.3 0.5 11*1.0 0.5 6*0.3
** Saturdays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW7 5*0.3 0.5 11*1.0 0.5 6*0.3
** Sundays: Mrs: 1-5 6 7-17 18 19-24
SO EMISFACT STK1 HRDOW7 5*0.3 0.5 11*1.0 0.5 6*0.3
SO EMISFACT STK1 MHRDOW enter 24 hourly scalars for each of the twelve months, first for
Weekdays
(Monday-Friday), then for Saturdays, and finally for Sundays, e.g.
** Weekdays JAN FEE MAR APR MAY JUN . . . NOV DEC
SO EMISFACT STK1 MHRDOW 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
** Saturdays:
SO EMISFACT STK1 MHRDOW 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
* * Sundays:
SO EMISFACT STK1 MHRDOW 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
SO EMISFACT STK1 MHRDOW7 enter 24 hourly scalars for each of the twelve months,
first for Mondays, then for Tuesdays, ..., then for Saturdays,
and finally for Sundays, e.g.,
** Mondays JAN FEE MAR APR MAY JUN . . . NOV DEC
SO EMISFACT STK1 MHRDOW7 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
** Tuesdays JAN FEE MAR APR MAY JUN . . . NOV DEC
SO EMISFACT STK1 MHRDOW7 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
** Saturdays:
SO EMISFACT STK1 MHRDOW7 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
** Sundays:
SO EMISFACT STK1 MHRDOW7 24*1.0 24*0.8 24*0.6 24*0.8 24*1.0 24*0.8 24*0.6 24*0.8
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2.5.2 Specifying an Hourly Emission Rate File (HOUREMIS)
The source (SO) pathway includes an option for inputting hourly emission rates for the
AERMOD model, controlled by the HOUREMIS keyword. AERMOD currently allows for a
single hourly emission file to be used with each model run. The syntax, type and order for this
keyword are summarized below:
Syntax: SO HOUREMIS Emifil Srcid's (and/or Srcrng's)
Type: Optional, Repeatable
Order: Must follow the LOCATION card for each source input
where the Emifil parameter specifies the filename for the hourly emission file, and Srcid or
Srcrng identify the source or sources for which hourly emission rates are included. The Emifil
filename can be up to 200 characters in length based on the default parameters in AERMOD.
Double quotes (") at the beginning and end of the filename can also be used as field delimiters to
allow filenames with embedded spaces. Source ranges, which are described in more detail in
Section 3.3.3 of the AERMOD User's Guide (EPA, 2004a), are input as two source IDs
separated by a dash, e.g., STACK1-STACK10. The user may include more than one
HOUREMIS card in a runstream file, if needed to specify additional sources, but there can be
only one hourly emissions file, and therefore the filename must be the same on all HOUREMIS
cards.
The format of each record of the hourly emissions file includes a pathway and keyword
(SO HOUREMIS), followed by the Year, Month, Day, Hour, Source ID, and emission rate (in
the appropriate units). For POINT sources, the stack gas exit temperature (K), and stack gas exit
velocity (m/s) are also specified. Beginning with version 09260, the release heights and initial
dispersion coefficients can also be varied on an hourly basis for AREA, AREAPOLY,
AREACIRC, and VOLUME sources using the HOUREMIS option. The user selects this
enhanced option by including the additional source parameters in the hourly emissions file.
AERMOD determines whether hourly release heights and initial dispersion coefficients are
being used based on the first HOUREMIS record for each source, and these additional
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parameters must be included on all HOUREMIS records unless the emissions are missing, which
is indicated but leaving the emission rate and all fields beyond the source ID blank.
The hourly emissions file is processed using the same routines used to process the
runstream input file, therefore each of the parameters must be separated by at least one space, but
otherwise the format is flexible. It is also not necessary to include the SO HOUREMIS on each
line, as long as the parameters (Year, Month, etc.) do not begin before column 13. The data in
the hourly emission file must also include the exact same dates as are included in the
meteorological input files, and the source IDs must correspond to the source IDs defined on the
SO LOCATION cards and be in the same order as defined in the 'aermod.inp' file.
The model will check for a date mismatch between the hourly emissions file and the
meteorological data, and also for a source ID mismatch. However, it is not necessary to process
the entire hourly emissions file on each model run, i.e., the correct emissions data will be read if
the ME DAYRANGE or the ME STARTEND cards (see Section 3.5.4 of the AERMOD User's
Guide) are used, as long as all the dates (including those that are processed and those that are
skipped) match the meteorological data files.
An example of several lines from an hourly emissions file for two point sources is
provided below:
SO HOUREMIS 88 8 16 1 STACK1 52.467 382.604 12.27
SO HOUREMIS 88 8 16 1 STACK2 44.327 432.326 22.17
SO HOUREMIS 88 8 16 2 STACK1 22.321 377.882 9.27
SO HOUREMIS 88 8 16 2 STACK2 42.166 437.682 19.67
SO HOUREMIS 88 8 16 3 STACK1 51.499 373.716 11.87
SO HOUREMIS 88 8 16 3 STACK2 41.349 437.276 18.77
SO HOUREMIS 88 8 16 4 STACK1 36.020 374.827 9.63
SO HOUREMIS 88 8 16 4 STACK2 43.672 437.682 18.23
The use of hourly varying release heights and initial dispersion coefficients for VOLUME and
AREA sources is illustrated in the following example:
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SO HOUREMIS 88 3 1 1 VOL1 500.0 2.0 2.0 2.0
SO HOUREMIS 88 3 1 1 AREA1 5.000 2.0 2.0
SO HOUREMIS 88 3 1 2 VOL1 500.0 2.0 2.0 3.0
SO HOUREMIS 88 3 1 2 AREA1 5.000 2.0 3.0
SO HOUREMIS 88 3 1 3 VOL1 500.0 2.0 2.0 4.0
SO HOUREMIS 88 3 1 3 AREA1 5.000 2.0 4.0
For POINT sources, the model will use the stack release height and stack inside diameter defined
on the SO SRCPARAM card, but will use the emission rate, exit temperature and exit velocity
from the hourly emission file. As noted above regarding VOLUME and AREA sources, if the
emission rate, exit temperature and exit velocity are not included for a particular hour, i.e, any or
all of those fields are blank, the model will interpret emissions data for that hour as missing and
will set the parameters to zero. Since the emission rate will be zero, there will be no calculations
made for that hour and that source.
2.6 OUTPUT FILE OPTIONS
Two new options have been incorporated on the OU pathway, beginning with version
09260 of AERMOD. The optional SUMMFILE keyword can be used to generate a separate
formatted output file containing the summary of high ranked values included at the end of the
standard 'aermod.ouf file. The optional FILEFORM keyword can be used to specify the use of
exponential notation, rather than fixed format as currently used, for results that are output to
separate result files.
The syntax, type and order of the optional SUMMFILE keyword are summarized below:
Syntax: OU SUMMFILE SummFileName
Type: Optional, Non-repeatable
where the SummFileName is the name of the external file containing the summary of high
ranked values. The SUMMFILE filename can be up to 200 characters in length based on the
default parameters in AERMOD. Double quotes (") at the beginning and end of the filename can
also be used as field delimiters to allow filenames with embedded spaces. In addition to the
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summary of high ranked values, the SUMMFILE also includes the "MODEL SETUP OPTIONS
SUMMARY" page from the main 'aermod.out' file.
The syntax, type and order of the optional FILEFORM keyword are summarized below:
Syntax: OU FILEFORM EXP or FIX
Type: Optional, Non-repeatable
where the EXP parameter specifies that output results files will use exponential-formatted
values, and the FIX parameter specifies that the output results files will use fixed-formatted
values. The default option is to use fixed-formatted results, so use of FILEFORM = 'FIX' is
extraneous. Note that AERMOD only examines the first three characters of the input field, so
that the full terms of 'EXPONENTIAL' or 'FIXED' can also be used. The format specified on
this optional keyword is applicable to PLOTFILEs, plot-formatted POSTFILEs, MAXIFILEs,
RANKFILEs, and SEASONHR files, but will not affect the format of results in the standard
'aermod.out' file or the optional SUMMFILE. The FILEFORM optional may be useful to
preserve precision in applications with relatively small impacts, especially for the purpose of
post-processing hourly concentrations using the POSTFILE option. The option may also be
useful for applications with relatively large impacts that may overflow the Fortran format
specifier of F13.5 used for fixed-formatted outputs. AERMOD will issue a warning message if
values that exceed the range allowed for fixed-format are detected unless the FILEFORM EXP
option has been selected.
2.7 MODEL STORAGE LIMITS
The AERMOD model has been designed using a dynamic storage allocation approach,
where the model allocates data storage as needed based on the number of sources, receptors,
source groups, and input requirements, up to the maximum amount of memory available on the
computer being used. The AERMOD model uses dynamic arrays to allocate data storage at
model runtime rather than at compile time. The AERMOD model preprocesses the model
runstream input file to determine the data storage requirements for a particular model run, and
46
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then allocates the input data arrays before processing the setup data. Once the setup processing is
completed, the model allocates storage for the result arrays. When allocating data storage, the
AERMOD model traps for errors, e.g., not enough memory available to allocate. If the allocation
is unsuccessful, then an error message is generated by the model and further processing is
prevented. If the CO RUNORNOT NOT option is selected, the model will still go through all
array allocations so that the user can determine if sufficient memory is available to complete the
run. Also, a rough estimate of the total amount of memory needed for a particular run is printed
out as part of the first page of printed output.
The storage parameters that are established at model runtime are as follows:
NSRC = Number of Sources
NREC = Number of Receptors
NGRP = Number of Source Groups
NOLM = Number of OLM Groups (OLMGROUP Keyword)
NAVE = Number of Short Term Averaging Periods
NVAL = Number of High Values by Receptor (RECTABLE Keyword)
NTYP = Number of Output Types (CONC currently is the only output type)
NMAX = Number of Overall Maximum Values (MAXTABLE Keyword)
NQF = Number of Variable Emission Rate Factors per Source
NPDMAX = Number of Particle Diameter Categories per Source
NVMAX = Number of Vertices for Area Sources (including AREA, AREACIRC, and
AREAPOLY source types) and/or OPENPIT Sources
NSEC = Number of Sectors for Building Downwash Parameters (set to 36 if
downwash sources are included)
NURB = Number of Urban Areas (URB ANOPT Keyword)
NNET = Number of Cartesian and/or Polar Receptor Networks
IXM = Number of X-coord (Distance) Values per Receptor Network
IYM = Number of Y-coord (Direction) Values per Receptor Network
NARC = Number of Receptor Arcs Used with EVALCART Keyword
NEVE = Number of Events for EVENT processing
47
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3.0 REFERENCES
Cimorelli, A. 1, S. G. Perry, A. Venkatram, J. C. Weil, R. J. Paine, R. B. Wilson, R. F. Lee, W.
D. Peters, R. W. Erode, and J. O. Paumier, 2004: AERMOD: Description of Model
Formulation. EPA 454/R-03-004. U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina 27711.
EPA, 1995a: User's Guide for the Industrial Source Complex (ISC3) Dispersion Models,
Volume I - User Instructions. EPA-454/B-95-003a. U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711.
EPA, 1995b: User's Guide for the Industrial Source Complex (ISC3) Dispersion Models,
Volume II - Description of Model Algorithms. EPA-454/B-95-003b. U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711.
EPA, 2003: AERMOD Deposition Algorithms - Science Document (Revised Draft). U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina 27711.
EPA, 2004a: User's Guide for the AMS/EPA Regulatory Model - AERMOD. EPA-
454/B-03-001. U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
27711.
EPA, 2004b: User's Guide for the AERMOD Meteorological Processor (AERMET). EPA-
454/B-03-002. U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
27711.
Hanrahan, P.L., 1999a. "The plume volume molar ratio method for determining NO2/NOx
ratios in modeling. Part I: Methodology," J. Air & Waste Manage. Assoc., 49, 1324-1331.
Hanrahan, P.L., 1999b. "The plume volume molar ratio method for determining NO2/NOx
ratios in modeling. Part II: Evaluation Studies," J. Air & Waste Manage. Assoc., 49, 1332-1338.
Walcek, C., G. Stensland, L. Zhang, H. Huang, J. Hales, C. Sweet, W. Massman, A. Williams, J,
Dicke, 2001: Scientific Peer-Review of the Report "Deposition Parameterization for the
Industrial Source Complex (ISC3) Model." The KEVRIC Company, Durham, North Carolina.
Wesely, M.L, P. V. Doskey, and J.D. Shannon, 2002: Deposition Parameterizations for the
Industrial Source Complex (ISC3) Model. Draft ANL report ANL/ER/TR-01/003, DOE/xx-
nnnn, Argonne National Laboratory, Argonne, Illinois 60439.
Note: All references listed here, with the exception of Hanrahan (1999a and 1999b), can be
found on the U.S. EPA SCRAM website at the following url: http://www.epa.gov/scram001/
48
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APPENDIX A. ALPHABETICAL KEYWORD REFERENCE
This appendix provides an alphabetical listing of all of the keywords used by the
AERMOD model. Each keyword is identified as to the pathway for which it applies, the
keyword type (either mandatory or optional, and either repeatable or non-repeatable), and with a
brief description of the function of the keyword. For a more complete description of the
keywords, including a list of associated parameters, refer to Section 2.0 of this Addendum, the
Functional Keyword/Parameter Reference in Appendix B of this Addendum, and/or the Detailed
Keyword Reference in Section 3 of the AERMOD User's Guide (EPA, 2004a).
A-l
-------
Keyword
AREA VERT
AVERTIME
BUILDHGT
BUILDLEN
BUILDWID
CONCUNIT
DAYRANGE
DAYTABLE
DCAYCOEF
DEBUGOPT
DEPOUNIT
DISCCART
DISCPOLR
ELEVUNIT
EMISFACT
EMISUNIT
ERRORFIL
EVALCART
EVALFILE
EVENTFIL
EVENTLOC
EVENTOUT
EVENTPER
FILEFORM
Path
SO
CO
so
so
so
CO
ME
OU
CO
CO
SO
RE
RE
SO
RE
SO
SO
CO
RE
OU
CO
EV
OU
EV
OU
Type
M-R
M-N
O-R
O-R
O-R
O-N
O-R
O-N
O-N
O-N
O-N
O-R
O-R
O-N
O-N
O-R
O-N
O-N
O-R
O-R
O-N
M-R
M-N
M-R
O-N
Keyword Description
Specifies location of vertices for an AREAPOLY source type
(mandatory if AREAPOLY source is used)
Averaging time(s) to process
Building height values for each wind sector
Building projected length values for each wind sector
Building projected width values for each wind sector
Optional conversion factors for emission input units and
concentration output units
Specifies days or ranges of days to process (default is to process all
data)
Option to provide summaries for each averaging period for each
day processed.
Optional decay coefficient for exponential decay
Option to generate detailed result and meteorology files for
debugging purposes
Optional conversion factors for emission input units and deposition
output units
Defines discretely placed receptors referenced to a Cartesian
system
Defines discretely placed receptors referenced to a polar system
Defines input units for receptor elevations (RE path), or source
elevations (SO path) (defaults to meters)
Optional input for variable emission rate factors
Optional conversion factors for emission units and concentration
units
Option to generate detailed error listing file (error file is mandatory
for CO RUNORNOT NOT case)
Defines discretely placed receptor locations referenced to a
Cartesian system, grouped by arc for use with the EVALFILE
output option
Option to output file of normalized arc maxima for model
evaluation studies
Specifies whether to generate an input file for EVENT model
Describes receptor location for an event
Specifies level of output information provided by the EVENT
model
Describes data and averaging period for an event
Specify fixed or exponential format for output results files
A-2
-------
Keyword
FINISHED
FLAGPOLE
GASDEPDF
GASDEPOS
GASDEPVD
GDLANUSE
GDSEASON
GRIDCART
GRIDPOLR
HALFLIFE
HOUREMIS
INCLUDED
INITFILE
LOCATION
MASSFRAX
MAXIFILE
MAXTABLE
METHOD 2
MODELOPT
MULTYEAR
NO2EQUIL
NO2RATIO
NO2STACK
OLMGROUP
OZONEFIL
Path
ALL
CO
CO
SO
CO
CO
CO
RE
RE
CO
SO
SO, RE,
EV
CO
SO
SO
OU
OU
SO
CO
CO
CO
SO
CO
so
CO
Type
M-N
O-N
O-N
O-R
O-N
O-N
O-N
O-R
O-R
O-N
O-R
O-R
O-N
M-R
O-R
O-R
O-R
O-R
M-N
O-N
O-N
O-R
O-N
O-R
O-N
Keyword Description
Identifies the end of inputs for a particular pathway
Specifies whether to accept receptor heights above local terrain (m)
for use with flagpole receptors, and allows for a default flagpole
height to be specified
Option to override default parameters for gas dry deposition
Specify source parameters for gas deposition algorithms
Option to specify deposition velocity for gas dry deposition
Specify land use categories by sector for gas dry deposition
Specify seasonal definitions for gas dry deposition
Defines a Cartesian grid receptor network
Defines a polar receptor network
Optional half-life for exponential decay
Option for specifying hourly emission rates in a separate file
Option to include input data from a separate file in the runstream
for the SO and/or RE pathways, or for the EV pathway for
EVENTs
Option to initialize model from file of intermediate results
generated by SAVEFILE option
Identifies coordinates for particular source location
Optional input of mass fraction for each particle size category
Option to list events exceeding a threshold value to file (if CO
EVENTFIL option is used, these events are included in the input
file generated for the EVENT model)
Option to summarize the overall maximum values
Specify optional source parameters for METHOD 2 option for
particle deposition
Job control and dispersion options
Specifies that run is part of a multi-year run, e.g., for PM-10 H6H
in five years
Option to override default NO2/NOx equilibrium ratio for
PVMRM
Option to specify in-stack NO2/NOx equilibrium ratio for OLM
and PVMRM options by source
Option to specify default in-stack NO2/NOx equilibrium ratio for
OLM and PVMRM options; may be overridden by NO2RATIO
Specifies sources to combine for OLM option for merging plumes
Specifies hourly ozone file for OLM and PVMRM options
A-3
-------
Keyword
OZONEVAL
PARTDENS
PARTDIAM
PLOTFILE
POLLUTID
POSTFILE
PROFBASE
PROFFILE
PSDGROUP
RANKFILE
RECTABLE
RUNORNOT
SAVEFILE
SCIMBYHR
SEASONHR
SITEDATA
SRCGROUP
SRCPARAM
STARTEND
STARTING
SUMMFILE
SURFDATA
SURFFILE
TITLEONE
TITLETWO
TOXXFILE
UAIRDATA
URBANOPT
URBANSRC
WDROTATE
WINDCATS
Path
CO
SO
SO
OU
CO
OU
ME
ME
SO
OU
OU
CO
CO
ME
OU
ME
SO
SO
ME
ALL
OU
ME
ME
CO
CO
OU
ME
CO
SO
ME
ME
Type
O-N
O-R
O-R
O-R
M-N
O-R
M-N
M-N
O-R
O-R
O-R
M-N
O-N
O-N
O-R
O-N
M-R
M-R
O-N
M-N
O-N
M-N
M-N
M-N
O-N
O-R
M-N
O-R
O-R
O-N
O-N
Keyword Description
Specifies background value of ozone for OLM and PVMRM
options
Specifies particle density by size category for particle deposition
Specifies particle diameters by size category for particle deposition
Option to write certain results to a storage file suitable for input to
plotting routines
Identifies pollutant being modeled
Option to write results to a mass storage file for postprocessing
Specifies the base elevation for the potential temperature profile
Describes input profile meteorological data file
Specifies source groups for PSDCREDIT option with PVMRM
Option to produce output file of ranked values for Q-Q plots
Option to output high ranked value (s) by receptor
Identifies whether to run model or process setup information only
Option to store intermediate results for later restart of the model
after user or system interrupt
Specifies sampling parameters for the SCIM option
Option to output values by season and hour-of-day
Describes on-site meteorological station
Identification of source groups
Identifies source parameters for a particular source
Specifies start and end dates to be read from input meteorological
data file (default is to read entire file)
Identifies the start of inputs for a particular pathway
Option to output summary of high ranked values to separate file
Surface meteorological station
Describes input surface meteorological data file
First line of title for output
Optional second line of output title
Creates output file for use with TOXX model component of
TOXST
Upper air meteorological station
Option to specify population for urban option
Option to specify use of urban option by source
Wind direction rotation adjustment
Upper bound of wind speed categories
A-4
-------
Keyword
XBADJ
YBADJ
Path
SO
SO
Type
O-R
O-R
Keyword Description
Along -flow distances from the stack to the center of the upwind
face of the projected building
Across-flow distances from the stack to the center of the upwind
face of the projected building
A-5
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APPENDIX B. FUNCTIONAL KEYWORD/PARAMETER REFERENCE
This appendix provides a functional reference for the keywords and parameters used by
the input runstream files for the AERMOD model. The keywords are organized by functional
pathway, and within each pathway the order of the keywords is based on the function of the
keyword within the preprocessor. The pathways used by the preprocessor are as follows, in the
order in which they appear in the runstream file and in the tables that follow:
CO - for specifying overall job COntrol options; and
SO - for specifying SOurce location information (optional);
D1? - for specifying REceptor information; and
- for specifying MEteorology information and options;
- for specifying EVent information and options;
- for specifying OUtput file information.
RE
ME
EV-
OU
The pathways and keywords are presented in the same order as in the Detailed Keyword
Reference in Section 3 of the AERMOD User's Guide (EPA, 2004a), and in the Quick Reference
at the end of the manual, with the exception of new keywords that are not reflected in the
original user's guide.
Two types of tables are provided for each pathway. The first table lists all of the
keywords for that pathway, identifies each keyword as to its type (either mandatory or optional
and either repeatable or non-repeatable), and provides a brief description of the function of the
keyword. The second type of table presents the parameters for each keyword, in the order in
which they should appear in the runstream file where order is important, and describes each
parameter in detail.
The following convention is used for identifying the different types of input parameters.
Parameters corresponding to secondary keywords which should be input "as is" are listed on the
tables with all capital letters and are underlined, although none of the inputs to AERMAP are
treated as case-sensitive. Other parameter names are given with an initial capital letter and are
not input "as is." In all cases, the parameter names are intended to be descriptive of the input
variable being represented, and they often correspond to the Fortran variable names used in the
B-l
-------
preprocessor code. Parentheses around a parameter indicate that the parameter is optional for
that keyword. The default that is taken when an optional parameter is left blank is explained in
the discussion for that parameter.
B-2
-------
TABLE B-l
DESCRIPTION OF CONTROL PATHWAY KEYWORDS
CO Keywords
STARTING
TITLEONE
TITLETWO
MODELOPT
AVERTIME
URBANOPT
POLLUTID
HALFLIFE
DCAYCOEF
GASDEPDF
GASDEPVD
GDLANUSE
GDSEASON
NO2EQUIL
NO2STACK
OZONEFIL
OZONEVAL
FLAGPOLE
RUNORNOT
EVENTFIL2
SAVEFILE3
INITFILE3
MULTYEAR3
DEBUGOPT
ERRORFIL
FINISHED
Type
M-N
M-N
O-N
M-N
M-N
O-R
M-N
O-N1
O-N1
O-N
O-N
O-N
O-N
O-N
O-N
O-N
O-N
O-N
M-N
O-N
O-N
O-N
O-N
O-N
O-N
M-N
Keyword Description
Identifies the start of CONTROL pathway inputs
First line of title for output
Optional second line of title for output
lob control and dispersion options
Averaging time(s) to process
Specifies parameters for urban dispersion option
Identifies type of pollutant being modeled
Optional half life used for exponential decay
Optional decay coefficient
Option to override default parameters for gas dry deposition
Option to specify deposition velocity for gas dry deposition
Specify land use categories by sector for gas dry deposition
Specify seasonal definitions for gas dry deposition
Option to override default NO2/NOx equilibrium ratio for PVMRM
Option to specify default in-stack NO2/NOx equilibrium ratio for OLM and
PVMRM options; may be overridden by NO2RATIO option on SO pathway
Specifies filename for hourly ozone file for use with OLM and PVMRM options
Specifies background value of ozone for use with OLM and PVMRM options
Specifies whether to accept receptor heights above local terrain (m) for use with
flagpole receptors, and allows for default flagpole height to be specified
Identifies whether to run model or process setup information only
Specifies whether to generate an input file for EVENT model
Option to store intermediate results for restart of model after user or system
interrupt
Option to initialize model from intermediate results generated by SAVEFILE option
Option to process multiple years of meteorological data (one year per run) and
accumulate high short term values across years
Option to generate detailed result and meteorology files for debugging purposes
Option to generate detailed error listing file
Identifies the end of CONTROL pathway inputs
-------
Type: M - Mandatory N - Non-Repeatable
O - Optional R - Repeatable
1) Either HALFLIFE or DCAYCOEF may be specified. If both cards appear a warning message
will be issued and the first value entered will be used in calculations. The DFAULT
option assumes a half life of 4 hours for S02 modeled in urban mode.
2) The EVENTFIL keyword controls whether or not to generate an input file for EVENT
processing. The primary difference between AERMOD regular processing and EVENT
processing by AERMOD is in the treatment of source group contributions. The AERMOD
model treats the source groups independently, whereas EVENT processing determines
individual source contributions to particular events, such as the design concentrations
determined from AERMOD, or user-specified events. By specifying the EVENTFIL keyword,
an input runstream file will be generated that can be used directly for EVENT
processing. The events included in the generated EVENT processing input file are
defined by the RECTABLE and MAXIFILE keywords on the OU pathway, and are placed in the
EVent pathway.
3) The SAVEFILE and INITFILE keywords work together to implement the model's re-start
capabilities. Since the MULTYEAR option utilizes the re-start features in a special
way to accumulate high short term values from year to year, it cannot be used together
with the SAVEFILE or INITFILE keyword in the same model run.
B-4
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TABLE B-2
DESCRIPTION OF CONTROL PATHWAY KEYWORDS AND PARAMETERS
Keyword
Parameters
TITLEONE
Title 1
where:
Title 1
First line of title for output, character string of up
to 68 characters
TITLETWO
Title2
where:
Title2
Optional second line of title for output, character
string of up to 68 characters
MODELOPT
DFAULT BETA CONG AREADPLT FLAT NOSTD NOCHKD NOWARN SCREEN SCIM PVMRM PSDCREDIT
DDEP
and/or
WDEP
DRYDPLT
or
FASTAREA
and/or
ELEV
WETDPLT
or
NOWETDPLT
where:
DFAULT
BETA
CONC
DEPPS
DDEP
WDEP
AREADPLT
FLAT
ELEV
NOSTD
NOCHKD
WARNCHKD
NOWARN
SCREEN
Specifies that regulatory default options will be used; specification
of DFAULT option will override non-DFAULT options that may
be specified;
Non-DFAULT option that allows for draft, "Beta" test options to be
used; includes PSDCREDIT option and capped and horizontal
stack releases;
Specifies that concentration values will be calculated;
Specifies that total deposition flux values will be calculated;
Specifies that dry deposition flux values will be calculated;
Specifies that wet deposition flux values will be calculated;
Specifies use of non-DFAULT method for optimized plume
depletion due to dry removal mechanisms for area sources;
Non-DFAULT option of assuming flat terrain will be used;
Default option of assuming elevated terrain will be used;
Note that FLAT and ELEV may be specified in the same model
run to allow specifying the non-DFAULT FLAT terrain option on
a source-by-source basis;
Non-DFAULT option of no stack-tip downwash will be used;
Non-DFAULT option of suspending date checking will be used for
non-sequential meteorological data files, also implemented when
SCREEN option is specified;
Specifies option for issuing warning messages rather than fatal errors
for non-sequential meteorological data files
Option to suppress detailed listing of warning messages in the main
output file will be used;
Non-DFAULT option for running AERMOD in a screening mode
for AERSCREEN will be used;
B-5
-------
Keyword
AVERTIME
where:
URBANOPT
where:
POLLUTID
where:
HALFLIFE
where:
DCAYCOEF
where:
Parameters
SCIM
PVMRM
OLM
PSDCREDIT
FASTALL
FASTAREA
DRYDPLT
NODRYDPLT
WETDPLT
NOWETDPLT
Sampled Chronological Input Model - ANNUAL averages only;
SCIM sampling parameters must be specified on the ME pathway;
Non-DFAULT Plume Volume Molar Ratio Method (PVMRM) for
NO2 conversion will be used;
Non-DFAULT Ozone Limiting Method (OLM) for NO2 conversion
will be used;
Specifies use of BETA test option to calculate the increment
consumption with PSD credits using the PVMRM option;
Non-DFAULT option to optimize model runtime for POINT,
VOLUME and AREA sources (AREA optimizations formerly
associated with TOXICS option);
Non-DFAULT option to optimize model runtime for AREA sources
(formerly associated with TOXICS option);
Option to incorporate dry depletion (removal) processes associated
with dry deposition algorithms; dry depletion will be used by
default if dry deposition algorithms are invoked;
Option to disable dry depletion (removal) processes;
Option to incorporate wet depletion (removal) processes associated
with wet deposition algorithms; wet depletion will be used by
default if wet deposition algorithms are invoked; and
Option to disable wet depletion (removal) processes.
Timel Time2 . . . TimeN MONTH PERIOD
or
ANNUAL
TimeN
MONTH
PERIOD
ANNUAL
Nth optional averaging time (123468 12 or 24-hr)
Option to calculate MONTHly averages (treated as
Option to calculate averages for the entire data PERIOD
Option to calculate ANNUAL averages (assumes complete years)
Urbpop (Urbname) (UrbRoughness)
UrbPop
UrbName
UrbRoughness
Specifies the population of the urban area
Specifies the name of the urban area (optional)
Specifies the urban surface roughness length, meters (optional,
defaults to 1.0m; value other than 1.0m treated as non-DFAULT)
Pollut
Pollut
Identifies type of pollutant being modeled. Any name of up to eight
characters mav be used. e.e.. SO2. NOX. CO. PM25. PM-2.5.
PM10. PM-10. TSP or OTHER. Use of PM10. PM-10 or OTHER
allows for the use of the MULTYEAR option.
Haflif
Haflif
Half life used for exponential decay (s)
Decay
Decay
Decay coefficient for exponential decay (s"1) = 0.693/HAFLIF
B-6
-------
Keyword
GASDEPDF
where:
GASDEPVD
where:
GDLANUSE
where:
GDSEASON
where:
NO2EQUIL
where:
NO2STACK
where:
OZONEFIL
where:
OZONEVAL
where:
FLAGPOLE
where:
Parameters
React F_Seas2 F_Seas5 (Refpoll)
React
F Seas2
F SeasS
(Refpoll)
Value for pollutant reactivity factor (Q
Fraction (F) of maximum green LAI for seasonal category 2
Fraction (F) of maximum green LAI for seasonal category 5
Optional name of reference pollutant
Uservd
Uservd
User-specified dry deposition velocity (m/s) for gaseous pollutants
Seel Sec2 ... Sec36
Seel
Sec2
Sec36
Land use category for winds blowing toward sector 1(10 degrees)
Land use category for winds blowing toward sector 2 (20 degrees)
Land use category for winds blowing toward sector 36 (360 degrees)
Jan Feb ... Dec
Jan
Dec
Seasonal category for January:
1 = Midsummer/Lush vegetation;
2 = Autumn/Unharvested cropland;
3 = Late autumn after harvest or Winter with no snow;
4 = Winter with continuous snow cover; or
5 = Transitional spring/partial green coverage/short annuals)
Seasonal category for December
NO2Equil
NO2Equil
Equilibrium ratio for PVMRM option (default is 0.9)
NO2Ratio
NO2Ratio
Default in-stack ratio of NO2/NOx for OLM and PVMRM options;
default is 0. 1 for OLM, which may be overridden by NO2RATIO
keyword on SO pathway
OSFileName (OSUnits) (Format)
OSFileName
(OSUnits)
(Format)
Filename for hourly ozone data file (YR, MN, DY, HR, O3Value)
Units of ozone data (PPM, PPB, or UG/M3); default is UG/M3
Fortran format statement to read ozone file; default is free-format,
i.e., comma or space-delimited data fields
OSValue (OSUnits)
OSValue
(OSUnits)
Background ozone concentration; also used to substitute for missing
data in OZONEFIL
Units of ozone value (PPM, PPB, or UG/M3); default is UG/M3
(Flagdf)
Flagdf
Default value for height of (flagpole) receptors above local ground, a
B-7
-------
Keyword
RUNORNOT
where:
EVENTFIL
where:
SAVEFILE
where:
INITFILE
where:
MULTYEAR
where:
DEBUGOPT
where:
ERRORFIL
where:
Parameters
RUN or NOT
RUN
NOT
default value of 0.0 m is used if this optional parameter is omitted
Indicates to run full model calculations
Indicates to process setup data and report errors, but to not run full
model calculations
(Evfile) (Evopt)
Evfile
Evopt
Identifies the filename to be used to generate a file for input to
EVENT model (Default=EVENTFIL.INP)
Optional parameter to specify the level of output detail selected for
the EVENT model: either SOCONT or DETAIL (default is
DETAIL if this parameter is omitted)
(Savfil) (Dayinc) (Savfl2)
Savfil
Dayinc
Savfl2
Specifies name of disk file to be used for storing intermediate results
(default = TMP.FIL) file is overwritten after each dump)
Number of days between dumps (optional: default is 1)
Optional second disk filename to be used on alternate dumps -
eliminates risk of system crash during the dump. If blank, file is
overwritten each time.
(Inifil)
Inifil
H6H Savfil dm
H6H
Savfil
Inifil
MODEL (Dbafi
MODEL
(Dbgfil)
METEOR
(Dbmfil)
Specifies name of disk file of intermediate results to be used for
initializing run (default = TMP.FIL)
fil)
Specifies the High- Sixth-High is being calculated for use in PM10
processing
Specifies name of file to be used for storing results at end of the year
Optional name of file used for initializing the results arrays from
previous year(s). The Inifil parameter is not used for the first year
in the multi-year run.
1) and/or METEOR (Dbmfil)
Specifies that MODEL debugging output will be generated
Optional filename for the model calculation debug file
Specifies that METEORological profile data file will be generated
Optional filename for the meteorological profile data file
(Errfil)
Errfil
Specifies name of detailed error listing file (default = ERRORS. LST)
-------
TABLE B-3
DESCRIPTION OF SOURCE PATHWAY KEYWORDS
SO Keywords
STARTING
ELEVUNIT
LOCATION
SRCPARAM
BUILDHGT
BUILDLEN
BUILDWID
XBADI
YBADI
AREA VERT
URBANSRC
EMISFACT
EMISUNIT
CONCUNIT
DEPOUNIT
PARTDIAM
MASSFRAX
PARTDENS
METHOD 2
GASDEPOS
NO2RATIO
HOUREMIS
INCLUDED
OLMGROUP
Type
M-N
O-N
M-R
M-R
O-R
O-R
O-R
O-R
O-R
M-R
O-R
O-R
O-N
O-N
O-N
O-R
O-R
O-R
O-R
O-R
O-R
O-R
O-R
O-R
Keyword Description
Identifies the start of SOURCE pathway inputs
Defines input units for source elevations (defaults to meters), must be first
keyword after SO STARTING if used.
Identifies coordinates for particular source
Identifies source parameters for a particular source
Building height values for each wind sector
Building projected length values for each wind sector
Building projected width values for each wind sector
Along -flow distances from the stack to the center of the upwind face of the
projected building
Across-flow distances from the stack to the center of the upwind face of the
projected building
Specifies location of vertices for an AREAPOLY source type (mandatory if
AREAPOLY source is used)
Identifies which sources to model with urban effects
Optional input for variable emission rate factors
Optional unit conversion factors for emissions, concentrations
Optional conversion factors for emissions and concentrations
Optional conversion factors for emissions and depositions
Input variables for optional input of particle size (microns)
Optional input of mass fraction for each particle size category
Optional input of particle density (g/cm3) for each size category
Optional input of parameters for METHOD_2 particle deposition
Optional input of gas deposition parameters
Option to specify in-stack NO2/NOx equilibrium ratio for OLM and
PVMRM options by source
Option for specifying hourly emission rates in a separate file
Option to include data from a separate file in the runstream
Specifies sources to combine for OLM option to account for merging
plumes
B-9
-------
SO Keywords
PSDGROUP1
SRCGROUP1
FINISHED
Type
O-R
M-R
M-N
Keyword Description
Specifies source groups for PSDCREDIT option with PVMRM
Identification of source groups
Identifies the end of SOURCE pathway inputs
1) The PSDGROUP or SRCGROUP keywords must be the last keyword within the SO pathway
before the FINISHED keyword. The SRCGROUP keyword is mandatory, unless the
PSDCREDIT option is used, which requires the PSDGROUP option instead.
B-10
-------
TABLE B-4
DESCRIPTION OF SOURCE PATHWAY KEYWORDS AND PARAMETERS
Keyword
Parameters
ELEVUNIT
METERS or FEET
where:
METERS
FEET
Specifies input units for source elevations of meters (default if
ELEVUNIT is omitted)
Specifies input units for source elevations of feet
Note: This keyword applies to source elevations only.
LOCATION
Srcid Srctyp Xs Ys (Zs)
where:
Srcid
Srctyp
Xs
Ys
Zs
Source identification code (alphanumeric string of up to eight
characters)
Source type: POINT. VOLUME. AREA. AREAPOLY. AREACIRC.
OPENPIT
x-coord of source location, corner for AREA. AREAPOLY. and
OPENPIT. center for AREACIRC (m)
y-coord of source location, corner for AREA. AREAPOLY. and
OPENPIT. center for AREACIRC (m)
Optional z-coord of source location (elevation above mean sea level,
defaults to 0.0 if omitted)
SRCPARAM
Srcid Ptemis Stkhgt Stktmp Stkvel Stkdia
Vlemis Relhgt Syinit Szinit
Aremis Relhgt Xinit (Yinit) (Angle) (Szinit)
Aremis Relhgt Nverts (Szinit)
Aremis Relhgt Radius (Nverts) (Szinit)
Opemis Relhgt Xinit Yinit Pitvol (Angle)
(POINT source)
(VOLUME source)
(AREA source)
(AREAPOLY source)
(AREACIRC source)
(OPENPIT source)
where:
Srcid
Emis
Hgt
Stktmp
Stkvel
Stkdia
Syinit
Szinit
Xinit
Yinit
Angle
Nverts
Source identification code
Source emission rate: in g/s for Ptemis or Vlemis, g/(s-m2) for Aremis
for concentration
Source physical release height above ground (center of height for
VOLUME, height above base of pit for OPENPIT)
Stack gas exit temperature (K)
Stack gas exit velocity (m/s)
Stack inside diameter (m)
Initial lateral dimension of VOLUME source (m)
Initial vertical dimension of VOLUME or AREA source (m)
Length of side of AREA source in X-direction (m)
Length of side of AREA source in Y-direction (m) (optional
parameter, assumed to be equal to Xinit if omitted)
Orientation angle (deg) of AREA or OPENPIT source relative to
North measured positive clockwise, rotated around the source
location, (XsYs) (optional parameter, assumed to be 0.0 if omitted)
Number of vertices used for AREAPOLY or AREACIRC source
(optional for AREACIRC sources)
B-ll
-------
Keyword
BUILDHGT
where:
BUILDWID
where:
XBADJ
where:
YBADJ
where:
AREA VERT
where:
URBANSRC
where:
EMISFACT
Parameters
Radius
Pitvol
Radius of circular area for AREACIRC source (m)
Volume of OPENPIT source (m3)
Srcid (or Srcrng) Dsbh(i), i=l,36
Srcid
Srcrng
Dsbh
Source identification code
Range of sources (inclusive) for which building
dimensions apply, entered as two alphanumeric
strings separated by a '-'
Array of direction-specific building heights (m)
beginning with 10 degree flow vector and increment-
ing by 10 degrees clockwise
Srcid (or Srcrng) Dsbw(i), i=l,36
Srcid
Srcrng
Dsbw
Source identification code
Range of sources (inclusive) for which building
dimensions apply
Array of direction-specific building widths (m)
beginning with 10 degree flow vector and increment-
ing by 10 degrees clockwise
Srcid (or Srcrng) Xbadj(i), i=l,36
Srcid
Srcrng
Xbadj(i)
Source identification code
Range of sources (inclusive) for which XBADJ distances apply
Array of direction-specific along -wind distances beginning with
10 degree flow vector and incrementing by 10 degrees clockwise
Srcid (or Srcrng) Ybadj(i), i=l,36
Srcid
Srcrng
Ybadj(i)
Source identification code
Range of sources (inclusive) for which YBADJ distances apply
Array of direction-specific across-wind distances beginning with 10
degree flow vector and incrementing by 10 degrees clockwise
Srcid Xv(l) Yv(l) Xv(2) Yv(2) ... Xv(i) Yv(i)
Srcid
Xv(l)
Yv(l)
Xv(i)
Yv(i)
Source identification code
X-coordinate of the first vertex of an AREAPOLY source (must be the
same as the value of Xs for that source defined on the SO
LOCATION card)
Y-coordinate of the first vertex of an AREAPOLY source (must be the
same as the value of Ys for that source defined on the SO
LOCATION card)
X-coordinate for the ith vertex of an AREAPOLY source
Y-coordinate for the ith vertex of an AREAPOLY source
Srcid's and/or Srcrng's
Srcid
Srcrng
Specifies which source(s) will be modeled with urban effects
Specifies a range of sources that will be modeled with urban effects
Srcid (or Srcrng) Qflag Qfact(i), i=l,n
B-12
-------
Keyword
where:
EMISUNIT
where:
CONCUNIT
where:
DEPOUNIT
where:
PARTDIAM
where:
MASSFRAX
where:
PARTDENS
Parameters
Srcid
Srcrng
Qflag
Qfact
Source identification code
Range of sources (inclusive) for which emission rate factors apply
Variable emission rate flag:
SEASON for seasona; MONTH for monthly; HROFDY for
hour-of-day; WSPEED for wind speed category; SEASHR for
season-by-hour; HRDOW for emission rates vary by hour-of-day.
and day-of-week [M-F, Sat, Sun]; HRDOW7 for emission rates
vary by hour-of-day, and the seven days of the week [M, Tu, W,
Th, F, Sat, Sun]; SHRDOW for season by hour-of-day by day-of-
week (M-F,Sat,Sun); SHRDOW7 for season by hour-of-day by
day-of-week (M,Tu,W,Th,F,Sat,Sun); MHRDOW for month by
hour-of-dav by dav-of-week (M-F.Sat.Sun); MHRDOW7 for
month by hour-of-day by day-of-week (M,Tu,W,Th,F,Sat,Sun)
Array of scalar emission rate factors, for:
SEASON. n=4; MONTH. n=12; HROFDY, n=24;
WSPEED. n=6; SEASHR. n=96; HRDOW. n=72;
HRDQW7,n=168; SHRDOW, n=28 8; SHRDQW7, n=672;
MHRDOW. n=864; MHRDOW7. n=2016
Emifac Emilbl Conlbl
Emifac
Emilbl
Conlbl
Emission rate factor used to adjust units of output (default value is
1 .OE06 for CONC for grams to micrograms)
Label to use for emission units (default is grams/sec)
Label to use for concentrations (default is micrograms/m3)
Emifac Emilbl Conlbl
Emifac
Emilbl
Conlbl
Emission rate factor used to adjust units of output (default value is
1 .OE06 for concentration for grams to micrograms)
Label to use for emission units (default is grams/sec)
Label to use for concentrations (default is micrograms/m3)
Emifac Emilbl Deplbl
Emifac
Emilbl
Deblbl
Emission rate factor used to adjust units of output for deposition
(default value is 3600 for grams/sec to grams/m2/hr)
Label to use for emission units (default is grams/sec)
Label to use for deposition (default is grams/m2)
Srcid (or Srcrng) Pdiam(i), i=l,Npd
Srcid
Srcrng
Pdiam
Source identification code
Range of sources (inclusive) for which size categories apply
Array of particle diameters (microns)
Srcid (or Srcrng) Phi(i), i=l,Npd
Srcid
Srcrng
Phi
Source identification code
Range of sources (inclusive) for which mass fractions apply
Array of mass fractions for each particle size category
Srcid (or Srcrng) Pdens(i), i=l,Npd
B-13
-------
Keyword
where:
METHOD 2
where:
GASDEPOS
where:
NO2RATIO
where:
HOUREMIS
where:
INCLUDED
where:
OLMGROUP
where:
PSDGROUP
where:
Parameters
Srcid
Srcrng
Pdens
Source identification code
Range of sources (inclusive) for which particle densities apply
Array of particle densities (g/cm3) for each size category
Srcid (or Srcrng) FineMassFraction Dmm
Srcid
FineMassFractio
n
Dmm
Source identification code
Fraction of particle mass emitted in fine mode, less than 2.5 microns
Representative mass mean particle diameter in microns
SrcID (or SrcRange) Da Dw rcl Henry
SrcID
Da
Dw
rcl
Henry
Source identification code
Diffusivity in air for the pollutant being modeled (cm2/s)
Diffusivity in water for the pollutant being modeled (cm2/s)
Cuticular resistance to uptake by lipids for individual leaves (s/cm)
Henry's Law constant (Pa m3/mol)
SrcID (or SrcRange) NO2Ratio
SrcID
SrcRange
NO2Ratio
Source identification code
Source ID range for specified ratio
In-stack ratio of NO2/NOx
Emifil Srcid's Srcrng's
Emifil
Srcid's
Srcrng's
Specifies name of the hourly emission rate file
Discrete source IDs that are included in the hourly emission file
Source ID ranges that are included in the hourly emission file
Incfil
SrcIncFile
Filename for the included source file, up to 200 characters in length;
double quotes (") may be used as delimiters for the filename to
allow for embedded spaces; and quotes don't count toward the limit
of 200
OLMGrpID SrcID's SrcRange's
OLMGrpID
SrcID's
SrcRange's
Group ID (Grpid = ALL specifies group including all sources)
Discrete source IDs to be included in group
Source ID ranges to be included in group
Note: Card may be repeated with same Grpid if
more space is needed to specify sources
PSDGrpID SrcID's SrcRange's
PSDGrpID
SrcID's
SrcRange's
PSD GroupID for PSDCREDIT option, must be one of the following:
INCRCONS - increment-consuming sources,
NONRBASE - non-retired baseline sources, or
RETRBASE - retired (increment-expanding) baseline sources.
Discrete source IDs to be included in group
Source ID ranges to be included in group
B-14
-------
Keyword
SRCGROUP
where:
Parameters
Note: Card may be repeated with same PSDGrpID if
more space is needed to specify sources
SrcGrpID SrcID's SrcRange's
SrcGrpID
SrcID's
SrcRange's
Group ID (Grpid = ALL specifies group including all sources)
Discrete source IDs to be included in group
Source ID ranges to be included in group
Note: Card may be repeated with same Grpid if
more space is needed to specify sources
B-15
-------
TABLE B-5
DESCRIPTION OF RECEPTOR PATHWAY KEYWORDS
RE Keywords
STARTING
ELEVUNIT
GRIDCART
GRIDPOLR
DISCCART
DISCPOLR
EVALCART
INCLUDED
FINISHED
Type
M-N
O-N
O'-R
O'-R
O'-R
O'-R
O'-R
O-R
M-N
Keyword Description
Identifies the start of RECEPTOR pathway inputs
Defines input units for receptor elevations (defaults to meters),
keyword after RE STARTING if used.
must be first
Defines a Cartesian grid receptor network
Defines a polar receptor network
Defines the discretely placed receptor locations referenced to a
system
Defines the discretely placed receptor locations referenced to a
Cartesian
polar system
Defines discrete Cartesian receptor locations for use with EVALFILE output
option
Identifies an external file containing receptor locations to be included in the
inputs
Identifies the end of RECEPTOR pathway inputs
1) At least one of the following must be present: GRIDCART, GRIDPOLR DISCCART,
DISCPOLR or EVALCART, unless the INCLUDED keyword is used to include receptor
inputs from an external file. Multiple receptor networks can be specified in a single run,
including both Cartesian and polar.
B-16
-------
TABLE B-6
DESCRIPTION OF RECEPTOR PATHWAY KEYWORDS AND PARAMETERS
Keyword
Parameters
ELEVUNIT
METERS or FEET
where:
METERS
FEET
Specifies input units for receptor elevations of meters
Specifies input units for receptor elevations of feet
Note: This keyword applies to receptor elevations only.
GRIDCART
Netid STA
XYINC Xinit Xnum Xdelta Yinit Ynum Ydelta
or XPNTS Gridxl Gridx2 GridxS .... GridxN, and
YPNTS Gridyl Gridy2 GridyS .... GridyN
ELEV Row Zelevl Zelev2 ZelevS ...ZelevN
FLAG Row Zflagl Zflag2 ZflagS ...ZflagN
END
where:
Netid
STA
XYINC
Xinit
Xnum
Xdelta
Yinit
Ynum
Ydelta
XPNTS
Gridxl
GridxN
YPNTS
Gridyl
GridyN
ELEV
Row
Zelev
FLAG
Row
Zflag
END
Receptor network identification code (up to eight alphanumeric
characters)
Indicates STArt of GRIDCART subpathway, repeat for each new Netid
Keyword identifying grid network generated from x and y increments
Starting local x-axis grid location in meters
Number of x-axis receptors
Spacing in meters between x-axis receptors
Starting local y-axis grid location in meters
Number of y-axis receptors
Spacing in meters between y-axis receptors
Keyword identifying grid network defined by a series of x and y
coordinates
Value of first x-coordinate for Cartesian grid
Value of 'nth' x-coordinate for Cartesian grid
Keyword identifying grid network defined by a series of x and y
coordinates
Value of first y-coordinate for Cartesian grid
Value of 'nth' y-coordinate for Cartesian grid
Keyword to specify that receptor elevations follow
Indicates which row (y-coordinate fixed) is being input
An array of receptor terrain elevations for a particular Row
Keyword to specify that flagpole receptor heights follow
Indicates which row (y-coordinate fixed) is being input
An array of receptor heights above local terrain elevation for a particular
Row (flagpole receptors)
Indicates END of GRIDCART subpathway, repeat for each new Netid
GRIDPOLR
Netid STA
ORIG Xinit
Srcid
Ringl
or ORIG
DIST
Yinit,
Ring2 RingS ... RingN
B-17
-------
Keyword
where:
DISCCART
where:
DISCPOLR
where:
Parameters
DDIR Dirl Dir2 Dir3 ... DirN.
or GDIR Dirnum Dirini Dirinc
ELEV Dir Zelevl Zelev2 ZelevS ... ZelevN
FLAG Dir Zflael Zflae2 ZflaaS ... ZflaeN
END
Netid
STA
ORIG
Xinit
Yinit
Srcid
DIST
Ringl
RingN
DDIR
Dirl
DirN
GDIR
Dirnum
Dirini
Dirinc
ELEV
Dir
Zelev
FLAG
Dir
Zflag
END
Receptor network identification code (up to eight alphanumeric characters)
Indicates STArt of GRIDPOLR subpathwav, repeat for each new Netid
Optional keyword to specify the origin of the polar network (assumed to
be at x=0, y=0 if omitted)
local x-coordinate for origin of polar network (m)
local y-coordinate for origin of polar network (m)
Source ID of source used as origin of polar network
Keyword to specify distances for the polar network
Distance to the first ring of polar coordinates (m)
Distance to the 'nth' ring of polar coordinates (m)
Keyword to specify discrete direction radials for the polar network
First direction radial in degrees (1 to 360)
The 'nth' direction radial in degrees (1 to 360)
Keyword to specify generated direction radials for the polar network
Number of directions used to define the polar system
Starting direction of the polar system
Increment (in degrees) for defining directions
Keyword to specify that receptor elevations follow
Indicates which direction is being input
An array of receptor terrain elevations for a particular direction radial
Keyword to specify that flagpole receptor heights follow
Indicates which direction is being input
An array of receptor heights above local terrain elevation for a particular
direction (flagpole receptors)
Indicates END of GRIDPOLR subpathwav, repeat for each new Netid
Xcoord Ycoord (Zelev) (Zflag)
Xcoord
Ycoord
Zelev
Zflag
local x-coordinate for discrete receptor location (m)
local y-coordinate for discrete receptor location (m)
Elevation above sea level for discrete receptor location (optional),
used only for ELEV terrain
Receptor height (flagpole) above local terrain (optional),
used only with FLAGPOLE keyword
Srcid Dist Direct (Zelev) (Zflag)
Srcid
Dist
Direct
Zelev
Zflag
Specifies source identification for which discrete polar receptor locations
apply (used to define the origin for the discrete polar receptor)
Downwind distance to receptor location (m)
Direction to receptor location, in degrees clockwise from North
Elevation above sea level for receptor location (optional),
used onlv for ELEV terrain
Receptor height (flagpole) above local terrain (optional),
B-18
-------
Keyword
EVALCART
where:
INCLUDED
where:
Parameters
used only with FLAGPOLE keyword
Xcoord Ycoord Zelev Zflag Arcid (Name)
Xcoord
Ycoord
Zelev
Zflag
Arcid
Name
Local x-coordinate for discrete receptor location (m)
Local y-coordinate for discrete receptor location (m)
Elevation above sea level for discrete receptor location (optional),
used only for ELEV terrain
Receptor height (flagpole) above local terrain (optional),
used only with FLAGPOLE keyword
Receptor arc ID used to group receptors along an arc or other grouping
(up to eight characters)
Optional name for receptor (up to eight characters)
RecIncFile
RecIncFile
Identifies the filename for the included receptor file, up to 200 characters
in length; double quotes (") may be used as delimiters for the filename to
allow for embedded spaces; and quotes don't count toward the limit of
200
B-19
-------
TABLE B-7
DESCRIPTION OF METEOROLOGY PATHWAY KEYWORDS
ME Keywords
STARTING
SURFFILE
PROFFILE
SURFDATA
UAIRDATA
SITEDATA
PROFBASE
STARTEND
DAYRANGE
SCIMBYHR
WDROTATE
WINDCATS
FINISHED
Type
M-N
M-N
M-N
M-N
M-N
O-N
M-N
O-N
O-R
O-N
O-N
O-N
M-N
Keyword Description
Identifies the start of METEOROLOGY pathway inputs
Describes input meteorological surface data file
Describes input meteorological profile data file
Describes surface meteorological station
Describes upper air meteorological station
Describes on-site meteorological station
Specifies the base elevation for the potential temperature profile
Specifies start and end dates to be read from input meteorological data file
(default is to read entire file)
Specifies days or ranges of days to process (default is to process all data)
Specifies the parameters for the SCIM (Sampled Chronological Input
Model) option (see CO MODELOPT)
May be used to correct for alignment problems of wind direction
measurements, or to convert wind direction from to flow vector
Input upper bounds of wind speed categories, five values input - sixth
category is assumed to have no upper bound (used for WSPEED option on
the EMISFACT keyword)
Identifies the end of METEOROLOGY pathway inputs
B-20
-------
TABLE B-8
DESCRIPTION OF METEOROLOGY PATHWAY KEYWORDS AND PARAMETERS
Keyword
SURFFILE
where:
PROFFILE
where:
SURFDATA
where:
UAIRDATA
where:
SITEDATA
where:
PROFBASE
where:
STARTEND
where:
Parameters
Sfcfil (Format)
Sfcfil
Format
Specify filename for surface meteorological input file
Specify format for input file (Note: FREE format is used for
SURFFILE reads beginning with version 09260)
all
Profil (Format)
Profil
Format
Specify filename for profile meteorological input file
Specify format for input file (Note: FREE format is used for all
SURFFILE reads beginning with version 09260)
Stanum Year (Name) (Xcoord Ycoord)
Stanum
Year
Name
Xcoord
Ycoord
Station number, e.g. 5 -digit WBAN number for NWS station
Year of data being processed (four digits)
Station name (optional)
x-coordinate of station location (m) (optional)
y-coordinate of station location (m) (optional)
Stanum Year (Name) (Xcoord Ycoord)
Stanum
Year
Name
Xcoord
Ycoord
Station number, e.g. 5 -digit WBAN number for NWS station
Year of data being processed (four digits)
Station name (optional)
x-coordinate of station location (m) (optional)
y-coordinate of station location (m) (optional)
Stanum Year (Name) (Xcoord Ycoord)
Stanum
Year
Name
Xcoord
Ycoord
Station number for on-site meteorological data station
Year of data being processed (four digits)
Station name (optional)
x-coordinate of station location (m) (optional)
y-coordinate of station location (m) (optional)
BaseElev (Units)
BaseElev
Units
Base elevation (above MSL) for the potential temperature prc
Units of BaseElev: METERS or FEET (default is METERS)
.file
Strtyr Strtmn Strtdy (Strthr) Endyr Endmn Enddy (Endhr)
Strtyr
Strtmn
Strtdy
Strthr
Endyr
Endmn
Year of first record to be read
Month of first record to be read
Day of first record to be read
Hour of first record to be read (optional)
Year of last record to be read
Month of last record to be read
B-21
-------
Keyword
DAYRANGE
where:
SCIMBYHR
where:
WDROTATE
where:
WINDCATS
where:
Parameters
Enddy
Endhr
Day of last record to be read
Hour of last record to be read (optional)
Note: File read begins with hour 1 of the start date and ends with
hour 24 of the end date if Stahr and Endhr are omitted.
Range 1 Range2 RangeS ... RangeN
Range 1
RangeN
First range of days to process, either as individual
day (XXX) or as range (XXX-YYY); days may be input
as Julian dates (XXX) or as month and day (XX/YY)
The 'nth' range of days to process
NRegStart NReglnt (SfcFilnam PflFilnam)
NRegStart
NReglnt
SfcFilnam
PflFilnam
Specifies the first hour to be sampled with the SCIM option;
required to have a value from 1 to 24
Specifies the sampling interval, in hours
Optional output file name to list the surface meteorological
data for the sampled hours
Optional output file name to list the profile meteorological
data for the sampled hours
Rotang
Rotang
Specifies angle (in degrees) to rotate wind direction
measurements to correct for alignment problems;
value of Rotang is subtracted from WD measurements,
i.e., rotation is counterclockwise
Wsl Ws2 Ws3 Ws4 Ws5
Wsl
Ws2
Ws3
Ws4
Ws5
Upper bound of first wind speed category (m/s)
Upper bound of second wind speed category (m/s)
Upper bound of third wind speed category (m/s)
Upper bound of fourth wind speed category (m/s)
Upper bound of fifth wind speed category (m/s)
(sixth category is assumed to have no upper bound)
B-22
-------
TABLE B-9
DESCRIPTION OF EVENT PATHWAY KEYWORDS
EV Keywords
STARTING
EVENTPER
EVENTLOC
INCLUDED
FINISHED
Type
M-N
M-R
M-R
O-R
M-N
Keyword Description
Identifies the start of EVENT pathway inputs
Describes data and averaging period for an event
Describes receptor location for an event
Identifies an external file containing EVENT data to be included in the
inputs
Identifies the end of EVENT pathway inputs
B-23
-------
TABLE B-10
DESCRIPTION OF EVENT PATHWAY KEYWORDS AND PARAMETERS
Keyword
EVENTPER
where:
EVENTLOC
where:
INCLUDED
where:
Parameters
Evname Aveper Grpid Date
Name
Grpid
Aveper
Date
Specify name of event to be processed (e.g. H2H24ALL),
(up to eight alphanumeric characters)
Specify source group ID for event
Specify averaging period for event
Specify data period for event (ending YYMMDDHH for
averaging period)
Evname XR=Xr YR=Yr (Zelev) (Zfiaz)
or
RNG= Rna DIR= Dir (Zelev) (ZQaz)
Evname
XR=
YR=
RNG=
DIR=
Zelev
Zflag
Specify name of event to be processed (e.g. H2H24ALL),
(up to eight alphanumeric characters)
X-coordinate for event (discrete Cartesian receptor)
Y-coordinate for event (discrete Cartesian receptor)
Distance range for event (discrete polar receptor)
Radial direction for event (discrete polar receptor)
Terrain elevation for event (optional)
Receptor height above ground for event (optional)
EventlncFile
EventlncFile
Identifies the filename for the included EVENT file, up to 200
characters in length; double quotes (") may be used as delimiters for
the filename to allow for embedded spaces; and quotes don't count
toward the limit of 200
EVENT locations can be input as either discrete Cartesian receptors (XR=, YR=)
or as discrete polar receptors (RNG=, DIR=). Events that are specified in the
file generated by the AERMOD model (CO EVENTFIL card) are always given as
discrete Cartesian coordinates. Discrete polar receptors are assumed to be
relative to an origin of (0,0) .
B-24
-------
TABLE B-11
DESCRIPTION OF OUTPUT PATHWAY KEYWORDS
OU Keywords
STARTING
RECTABLE
MAXTABLE
DAYTABLE
MAXIFILE
POSTFILE1
PLOTFILE1
TOXXFILE
RANKFILE
EVALFILE
SEASONHR
SUMMFILE
FILEFORM
EVENTOUT
FINISHED
Type
M-N
O-R
O-R
O-N
O-R
O-R
O-R
O-R
O-R
O-R
O-R
O-N
O-N
M-N
M-N
Keyword Description
Identifies the start of OUTPUT pathway inputs
Option to specify value(s) by receptor for output
Option to summarize the overall maximum values
Option to print summaries for each averaging period for each day
processed.
Option to list events exceeding a threshold value to file (if CO
EVENTFIL option is used, these events are included in the input file
generated for the EVENT model).
Option to write results to a mass storage file for postprocessing.
Option to write certain results to a storage file suitable for
input to plotting routines
Option to write results to a storage file suitable for input to the
TOXX model component of TOXST or the RISK
Option to output file of ranked values for Q-Q plots (must be used
with the MAXTABLE keyword)
Option to output file of normalized arc maxima from EVALCART
receptors for model evaluation studies
Option to output results by season and hour-of-day
Option to output summary of high ranked values to separate file
Specify fixed or exponential format for output results files
Specifies the level of output information provided for EVENT
Processing [EVENT Only]
Identifies the end of OUTPUT pathway inputs
1) POSTFILE is used to output concurrent concentration values for particular source
groups and averaging times across the receptor network suitable for postprocessing.
PLOTFILE is used to output specific design values, such as second high
concentrations, across the receptor network, suitable for plotting concentration
contours.
B-25
-------
TABLE B-12
DESCRIPTION OF OUTPUT PATHWAY KEYWORDS AND PARAMETERS
Keyword
RECTABLE
where:
MAXTABLE
where:
DAYTABLE
where:
MAXIFILE
where:
POSTFILE
where:
Parameters
Aveper FIRST S
Aveper 1ST 2>
ECOND . . . SIXTH . . . TENTH or
ID ... 6TH . . . 10TH
Aveper
FIRST
SECOND
SIXTH
1ST
2ND
6TH
Averaging period to summarize with high values
(kevword ALLAVE specifies all averaging periods)
Select summaries of FIRST highest values by receptor
Select summaries of SECOND highest values by receptor
Select summaries of SIXTH highest values by receptor
Select summaries of 1ST highest values by receptor
Select summaries of 2ND highest values by receptor
Select summaries of 6TH highest values by receptor
Note: If two keywords are input separated by a dash (e.g.
FIRST-THIRD) . then summaries of all high values in that
range are provided. Also, if the CO EVENTFIL keyword is
exercised, then the events generated by the RECTABLE
keyword are included in the input file for EVENT model.
Aveper Maxnum
Aveper
Maxnum
Averaging period to summarize with overall maximum values
(keyword ALLAVE specifies all averaging periods)
Specifies number of overall maximum values to summarize
Avperl Avper2 AvperS . . .
Avperl
Averaging period, e.g., 24 for 24-hr averages, to summarize
with values by receptor for each day of data processed (keyword
ALLAVE for first parameter specifies all averaging periods)
Aveper Grpid Thresh Filnam (Funit)
Aveper
Grpid
Thresh
Filnam
Funit
Specifies averaging period for list of values equal to or exceeding a
threshold value
Specifies source group to be output to file
Threshold value (e.g. NAAQS) for list of exceedances
Name of disk file to store maximum values
Optional parameter to specify the file unit
Note: If the CO EVENTFIL keyword is exercised, then the
events generated by the MAXIFILE keyword are included
in the input file for EVENT processing.
Aveper Grpid Format Filnam (Funit)
Aveper
Grpid
Format
Specifies averaging period to be output to file,
e.g.. 24 for 24-hr averages, PERIOD for period averages
Specifies source group to be output to file
Specifies format of file, either UNFORM for
B-26
-------
Keyword
PLOTFILE
where:
TOXXFILE
where:
RANKFILE
where:
EVALFILE
where:
SEASONHR
SUMMFILE
FILEFORM
Parameters
Filnam
Funit
unformatted files or PLOT for formatted files for plotting
Specifies filename for output file
Optional parameter to specify the file unit
Aveper Grpid Hivalu Filnam (Funit) (Short Term values)
Aveper Grpid Filnam (Funit) (PERIOD or ANNUAL averages)
Aveper
Grpid
Hivalu
Filnam
Funit
Specifies averaging period to be output to file, e.g., 24 for
24-hr averages, PERIOD for period averages, etc.
Specifies source group to be output to file
Specifies hiah value summarv (e.e. FIRST. SECOND. 1ST. 2ND.
etc.) to be output to file (must be selected on RECTABLE card)
Specifies filename for output file
Optional parameter to specify the file unit
Aveper Cutoff Filnam (Funit)
Aveper
Cutoff
Filnam
Funit
Specifies averaging period to be output to file,
e.g., 1 for 1-hr averages.
Specifies cutoff (threshold) value in g/m3 for outputting
results for AERMOD model
Specifies filename for output file
Optional parameter to specify the file unit
Aveper Hinum Filnam (Funit)
Aveper
Hinum
Filnam
Funit
Specifies averaging period to be output to file,
e.g., 24 for 24-hr averages
Specifies the number of high values to be ranked
Specifies filename for output file
Optional parameter to specify the file unit
Srcid Filnam (Funit)
Srcid
Filnam
Funit
Specifies the source ID to be output to file
Specifies filename for output file
Optional parameter to specify the file unit
GroupID FileName (FileUnit)
GroupID
FileName
(FileUnit)
Specifies the source group ID to be output to file
Specifies filename for output file
Optional parameter to specify file unit
SummFileName
SummFileName
EXP or FIX
EXP
FIX
Specifies filename of output file
Specifies that the output results files will use exponential-formatted
values
Specifies that the output results files will use fixed-formatted
values
B-27
-------
Keyword
EVENTOUT
where:
Parameters
SOCONT or DETAIL [EVENT Onlvl
SOCONT
DETAIL
Provide source contribution information only in the event output
Include hourly concentrations for each source and hourly
meteorological data in the event output
B-28
-------
APPENDIX C. LIST OF ERROR/WARNING MESSAGES
This appendix provides a list of error, warning and informational messages used in the
current version of the AERMOD model. Three types of messages can be produced by the model
during processing of model inputs and during model calculations. These are described below:
• Fatal Errors that will halt any further processing, except to identify additional error
conditions (type E);
• Warnings that do not halt processing but indicate possible errors or suspect
conditions (type W); and
• Informational messages that may be of interest to the user but have no direct bearing
on the validity of the results (type I).
A more detailed explanation of the error handling and reporting procedures used in AERMOD is
provided Appendix C of the AERMOD User's Guide (EPA, 2004a). The three message types
are identified with the letters E (errors), W (warnings), and I (informational messages). The 3-
digit message numbers are generally grouped into categories corresponding to the different
stages of the processing, although these distinctions may not always be obvious. Theses
categories are:
100-199 Input Runstream Image Structure Processing
200 - 299 Parameter Setup Processing
300-399 Data and Quality Assurance Processing
400 - 499 Run Time Message Processing
500 - 599 Input/Output Message Processing
The list provided below includes the message number, the main message text, and the "hint"
field that may include additional details regarding the message. Note that the listing of messages
in the AERMOD User's Guide (EPA, 2004a) is not up-to-date. Several additional messages
have been added to AERMOD since that time, and the numbering of some messages may have
changed.
C-l
-------
Message
Number
100
105
110
115
120
125
130
135
140
141
142
143
144
145
146
147
149
150
152
154
155
156
157
158
159
160
170
175
180
185
189
190
191
192
Error/Warning Message
Invalid Pathway Specified. The Troubled Pathway is
Invalid Keyword Specified. The Troubled Keyword is
Keyword is Not Valid for This Pathway. Keyword is
STARTING or FINISHED Out of Sequence: Pathway =
Pathway is Out of Sequence: Pathway =
Missing FINISHED-Runstream File Incomplete: ISTAT=
Missing Mandatory Keyword. The Missing Keyword is
Nonrepeatable Keyword or Recursed INCLUDED: Keywrd
Invalid Order of Keyword. The Troubled Keyword is
Conflicting Options: PVMRM and OLM both specified
Following Keyword Invalid Without PVMRM or OLM:
Following Keyword Invalid Without PVMRM Option:
Following Keyword Invalid Without OLM Option:
Conflicting Options: MULTYEAR and Re-Start Option
PSDGROUP Keyword Specified without PSDCREDIT Opt.
Following Option is Invalid with PSDCREDIT Option:
Conflicting options specified on MODELOPT keyword:
Conflicting Options: MULTYEAR for Wrong Pollutant
ELEVUNIT card must be first for this Pathway:
Conflicting options: SCIM cannot be used with
Conflicting Decay Keyword. Inputs Ignored for
Option ignored - not valid with SCIM. Option =
Wet SCIM Not Supported - Wet SCIM Inputs Ignored
EMISUNIT Keyword Used With More Than 1 Output Type
EMISUNIT Keyword Used With the Following Keyword:
Duplicate ORIG Secondary Keyword for GRIDPOLR:
Invalid Secondary Keyword for Receptor Grid:
Missing Secondary Keyword END for Receptor Grid:
Conflicting Secondary Keyword for Receptor Grid:
Missing Receptor Keywords. No Receptors Specified.
No Keywords for OU Path and No PERIOD/ANNUAL Aves.
Incompatible Option Used With SAVEFILE or INITFILE
PM-2.5 without MAXIFILE is incompatible with
FASTALL option also implies use of FASTAREA option
Hint
Path
Keyword
Path
Path
Path
Keyword
Keyword
Keyword
Keyword
Keyword
Keyword
Keyword
Keyword
Option
Option
Keyword
Path
ST AVEs
Keyword
DEPOS
Keyword
Keyword
NETID
NETID
NETID
NETID
Keyword
EVENTFIL
C-2
-------
Message
Number
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
Error/Warning Message
Incompatible Keyword used with GASDEPVD option
Gas deposition algorithms are non-DFAULT options
METHOD_2 for participates is a non-DFAULT option
TOXICS Option obsolete; see Users Guide Addendum
Non-DFAULT BETA Option Required for
Missing Parameter(s). No Options Specified For
Not Enough Parameters Specified For the Keyword of
Too Many Parameters Specified For the Keyword of
Invalid Parameter Specified. Troubled Parameter:
Regulatory DFAULT Conflicts with Non-DFAULT Option
No Option Parameter Setting. Forced by Default to
Regulatory DFAULT Overrides Non-DFAULT Option For
No Parameters Specified. Default Values Will Used.
Illegal Numerical Field Encountered in
Negative Value Appears For Non-negative Variable.
Number of Short Term Averages Exceeds Max: NAVE =
Duplicate Averaging Period Specified for Keyword
END Encountered Without (X,Y) Points Properly Set
ELEV Input Inconsistent With Option: Input Ignored
ELEV Input Inconsistent With Option: Defaults Used
FLAG Input Inconsistent With Option: Input Ignored
FLAG Input Inconsistent With Option: Defaults Used
More Than One Delimiter In A Field for Keyword
Number of (X,Y) Points Not Match With Number Of
Number Of Receptors Specified Exceeds Max: NREC =
Missing Origin (Use Default = 0,0) In GRIDPOLR
Missing Distance Setting In Polar Network
Missing Degree Or Dist Setting In Polar Network
Missing Distance or Degree Field in
Number of Receptor Networks Exceeds Max: NNET =
Number of X-Coords Specified Exceeds Max: IXM =
Number of Y-Coords Specified Exceeds Max: IYM =
No Receptors Were Defined on the RE Pathway.
Default(s) Used for Missing Parameters on Keyword
Too Many Parameters - Inputs Ignored on Keyword
Hint
Keyword
Keyword
Option
Keyword
Keyword
Keyword
Parameter
Option
Option
Keyword
Variable
Keyword
NETID
NETID
NETID
NETID
NETID
Keyword
NETID
NETID
NETID
Keyword
Keyword
C-2
-------
Message
Number
230
231
232
233
234
235
236
237
239
240
241
242
243
244
245
246
247
248
249
250
252
254
256
259
260
262
264
265
266
270
275
280
281
282
Error/Warning Message
Source ID field is too long (>8); first 8 chars:
Too Many Numerical Values Specified for
Number Of Specified Sources Exceeds Maximum: NSRC=
Building Dimensions Specified for Non-POINT Source
Too Many Sectors Input for
Number of Source Groups Exceeds Maximum: NGRP =
Not Enough BUILDHGTs Specified for SourcelD
Not Enough BUILDWIDs Specified for SourcelD
Not Enough QFACTs Specified for SourcelD
Inconsistent Number of Particle Categories for
Not Enough BUILDLENs Specified for SourcelD
No Particle Cat. or Gas Depos. Specified for SRCID
Wet depos (DEPOS, WDEP, WETDPLT) incompatible with
Source parameters are missing or incomplete for
No. of Particle Categories Exceeds Max: NPDMAX =
Not Enough XBADJs Specified for SourcelD
Not Enough YBADJs Specified for SourcelD
No Sources Were Defined on the SO Pathway.
Source elevation is missing (-9999.0); SRCID =
Duplicate XPNT/DIST or YPNT/DIR Specified for GRID
Duplicate Receptor Network ID Specified. NETID =
Number of Receptor ARCs Exceeds Max: NARC =
EVALFILE Option Used Without EVALCART Receptors
Receptor elevation is missing (-9999.0); IREC =
Number of Emission Factors Exceeds Max: NQF =
First Vertex Does Not Match LOCATION for AREAPOLY
Too Many Vertices Specified for AREAPOLY Source
Not Enough Vertices Specified for AREAPOLY Source
Invalid shape defined (area=0) for AREAPOLY source
Number of High Values Specified Exceeds Max: NVAL=
Number of Max Values Specified Exceeds Max: NMAX=
Number of Output Types Specified Exceeds Max:NTYP=
Number of OLMGROUPs Specified Exceeds Max: NOLM =
Following SRCID Included in Multiple OLMGROUPs:
Hint
SRCID(1:8)
EMISFACT
SRCID
Keyword
SRCID
SRCID
SRCID
SRCID
SRCID
SRCID
GASDEPVD
DRYDEP or
WETDEP
SRCID
SRCID
SRCID
NETID
NETID
NUMARC=0
Rec Number
SRCID
SRCID
SRCID
SRCID
SRCID
C-4
-------
Message
Number
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
310
313
315
317
318
319
320
322
324
325
330
332
334
335
Error/Warning Message
Either OZONEVAL or OZONEFIL Card Needed for Option
Invalid POLLUTID Specified for PVMRM/OLM; Must Use
Number of Urban Areas Exceeds Maximum. NURB =
Following SRCID Included in Multiple PSDGROUPs:
PSDGROUP ID Must be INCRCONS, RETRBASE or NONRBASE
Use of "*" for repeated values not meaningful for
Source defined as both particulate and gaseous
Number of Events Specified Exceeds Max: NEVE =
Filename specified is too long. Maximum length =
Format specified is too long. Maximum length =
User-specified met data format not used; use FREE
PERIOD and ANNUAL averages are both selected for
Invalid Averaging Period Specified for SCREEN Mode
Averaging Period .NE. 1-Hr for TOXXFILE Option
Aver. Period must be .LE. 24 for EVENT Processing
Error Allocating Storage for Setup Arrays!
Error Allocating Storage for Result Arrays!
Specified SRCID Has Not Been Defined Yet: KEYWORD=
Urban Area ID Has Not Been Defined. URBID =
Following SRCID Included in Multiple Urban Areas:
Urban ID has already been defined. URBID =
Attempt to Define Duplicate LOCATION Card for SRC:
Attempt to Define Duplicate EVENTPER card for
Attempt to Define Duplicate SRCPARAM Card for SRC:
Specified SRCID not included in any PSD/SRCGROUP:
No Sources Defined for Urban Area. URBID =
No Sources Included in Specified Source Group:
Input Parameter May Be Out-of-Range for Parameter
Release Height Exceeds Effective Depth for OPENPIT
Release Height Exceeds 3000 Meters for SRCID:
Negative Exit Velocity (Set=1.0E-5) for SRCID:
Mass Fraction Parameters Do Not Sum to 1 . for Src
Mass Fraction Parameter Out-of-Range for Source
Particle Density Out-of-Range for Source
Particle Diameter Out-of-Range for Source
Hint
OLM or PVMRM
NO2
SRCID
Keyword
SRCID
ILEN FLD
ILEN FLD
Format
Keyword
Ihr Only
EVNAME
Error Code
Error Code
Keyword
Urban ID
SRCID
Urban ID
SRCID
EVNAME
SRCID
SRCID
Urban ID
GRPID
Parameter
SRCID
SRCID
SRCID
SRCID
SRCID
SRCID
SRCID
C-5
-------
Message
Number
336
338
340
342
344
345
346
350
352
353
354
360
363
365
370
380
381
382
384
386
387
391
392
395
397
398
399
400
405
406
410
413
420
430
432
Error/Warning Message
NO2RATIO Invalid or Not Specified for PVMRM Source
Neg Emis Rate Cannot be Used with OLM/PVMRM. Src:
Possible Error in PROFBASE Input: Value is < 0
Src ID Mismatch in Hourly Emissions File for ID =
Missing HOUREMIS fields; EmisRate set = 0. KURDAT=
Problem processing the HOUREMIS file. KURD AT =
Too many fields for HOUREMIS file . KURDAT =
Julian Day Out Of Range at
Missing Field on MULTYEAR Keyword for
Urban Roughness Length (m) May Be Out-of-Range:
High-8th-High Only Required for PM-2.5 24-hr Ave
2-Digit Year Specified: Valid for Range 1950-2049
24HR and ANNUAL Averages Only for PM-2.5 NAAQS
Year Input is Greater Than 2147
Invalid Date: 2/29 In a Non-leap Year.
This Input Variable is Out-of-Range:
Latitude in Surface File Is Not Valid:
Error Decoding Latitude:
Not enough fields specified for HOUREMIS; KURDAT =
PARTDIAM and METHOD_2 specified for same SRCID:
METHOD_2 option already specified for this SRCID:
Aspect ratio (LAV) of area source greater than 100
Aspect ratio (LAV) of open pit is greater than 10
Met. Data Error; Incompatible Version of AERMET:
SCREEN option used without use of SCREEN Met Data
SCREEN met used without specifying SCREEN option
EXP format specified with no applicable file types
Output values exceed format limit; use OU FILEFORM
Value of PHEE Exceeds 1.0 on KURDAT =
Numer of Vertices Exceeds Maximum (NVMAX) for Src:
Wind Direction Out-of-Range. KURDAT =
Number of Threshold Events > 9999 for Ave Period
Wind Speed Out-of-Range. KURDAT =
Ambient Temperature Data Out-of-Range. KURDAT =
Friction Velocity Out-of-Range. KURDAT =
Hint
SRCID
SRCID
Keyword
SRCID
YYMMDDHH
YYMMDDHH
YYMMDDHH
JDAY
H6H
URBZO
RECTABLE
Keyword
AVERTIME
Keyword or YR =
YR =
Lat
Lat
YYMMDDHH
SRCID
SRCID
SRCID
SRCID
Version Date
Version Date
FILEFORM
= EXP
YYMMDDHH
SRCID
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
C-6
-------
Message
Number
435
438
439
440
441
442
450
455
456
457
458
459
460
465
470
474
475
480
481
483
484
485
486
488
489
490
495
496
499
500
510
520
Error/Warning Message
Surface Roughness Length Out-of-Range. KURD AT =
Convective Velocity Data Out-of-Range. KURD AT =
Monin-Obukhov Length Out-of-Range. KURD AT =
Calm Hour Identified in Meteorology Data File at
Vert Pot Temp Grad abv ZI set to min .005, KURDAT=
Vert Pot Temp Grad abv ZI exceeds 0.1 K/m, KURDAT=
Record Out of Sequence in Meteorological File at:
Date/time Mismatch: Hourly Emission File. KURD AT =
Date/time Mismatch on Surface & Profile. KURD AT =
Date/time Mismatch on OZONEFIL Data. KURD AT =
Substitution made for missing ozone data. KURD AT =
Missing ozone data; Full conversion used. KURD AT =
Missing Hour Identified in Meteor. Data File at
Number of Profile Levels Exceeds Max: MXPLVL =
Mixing Height Value is < or = 0.0. KURD AT =
WS RefHt invalid (<0.001); Not msg or elm: KURDAT=
WS reference height is higher than 100m. KURD AT =
Less Than 1 Year Found for ANNUAL Averages
Data Remaining After End of Year. Number of Hours=
User Start Date is Earlier Than Start of Met File
Restart Date < STARTEND date or start of met file
MULTYR DataGap; Restart Date < STARTEND or MetFile
MULTYR Date Overlap; STARTEND Date < Restart Date
First met HR.ne. 1; ST results may not be valid for
First met HR.ne. 1; EV results may not be valid for
Problem reading SURFFILE date for EVENTS; MNDYHR =
Surface met file does not include enough variables
Total precipitation in SURFFILE is zero (0.0) with
PRIME plume rise error; check stack parameters for
Fatal Error Occurs Opening the Data File of
Fatal Error Occurs During Reading of the File of
Fatal Error Occurs During Writing to the File of
Hint
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
YYMMDDHH
STARTEND or
YYMMDDHH
STARTEND or
YYMMDDHH
YYMMDDHH
First Day
MnDyHr
MnDyHr
with-DEP or
Non-DEP
WetDepos
SRCID
FileName or
FileType
FileType
FileType and Unit
C-7
-------
Message
Number
530
540
550
555
560
565
570
580
585
590
Error/Warning Message
CAUTION! Met Station ID Mismatch with SURFFILE for
No RECTABLE/MAXTABLE/DAYTABLE for Average Period
File Unit/Name Conflict for the Output Option:
File Unit/Name conflict across options: GRP# AVE
User Specified File Unit .LT. 30 for OU Keyword:
Possible Conflict With Dynamically Allocated FUNIT
Problem Reading Temporary Event File for Event:
End of File Reached Trying to Read the File of
Output data file for INITFILE option was not found
The INITFILE filename matches a SAVEFILE filename
Hint
Keyword
nnn-HR
Keyword
GrpNum and
AvePer
Keyword
Keyword
EVNAME
Keyword
File Type
-------
APPENDIX D
EPA Model Clearinghouse Memorandum
Dated July 9,1993
D-l
-------
July 9, 1993
MEMORANDUM
SUBJECT: Proposal for Calculating Plume Rise for Stacks with Horizontal
Releases or Rain Caps for Cookson Pigment, Newark, New Jersey
FROM: Joseph A. Tikvart, Chief
Source Receptor Analysis Branch, TSD (MD-14)
TO: Ken Eng, Chief
Air Compliance Branch, Region II
In response to your request, the Model Clearinghouse has reviewed your
proposal for treating horizontal and capped stacks at Cookson Pigment so
that the model (SCREEN or ISC2) will properly treat plume rise from the
Cookson Pigment stacks. We concur in principle with the approach, with
some relatively minor changes.
First, the analysis provided by New Jersey Department of Environmental
Protection is technically correct. We suggest, however, that the exit
velocity for horizontal and capped stacks be set to a lower figure than 0.1
m/s. A 0.1 m/s exit velocity may still result in significant momentum
plume rise being calculated, even though these kinds of sources should have
zero momentum rise. We therefore suggest setting the stack exit velocity
to a lower value, such as .001.
For horizontal stacks that are not capped, we suggest turning stack
tip downwash off, whether there are buildings or not. Stack tip downwash
calculations are inappropriate for horizontal stacks.
For vertical stacks that are capped, turn stack tip downwash off and
reduce the stack height by three times the actual stack diameter. The cap
will probably force stack tip downwash most of the time. The maximum
amount of the stack tip downwash (as calculated in ISC2) is three times the
stack diameter. Reducing the stack height by this amount, while turning
off the stack tip downwash option, causes the maximum stack tip downwash
effect. The resulting concentrations may err slightly on the high side.
For stacks with small diameters, such as those at Cookson Pigment, the
error should be quite small. Note, however, that this approach may not be
valid for large diameter stacks (say, several meters).
cc: A. Colecchia
D. Wilson
D-2
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