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Support Center for Regulatory Atmospheric Modeling (SCRAM)

SCRAM Frequently Asked Questions

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(Last Revision: April 18, 2013)

Note: These FAQs are here to help you and to answer often repeated questions. If you find an error, or something is confusing, or there may be a topic or question that you think should be added below, please feel free to send an email to us through SCRAM’s Contact Us page.

Administrative and Other Structures

Administrative Structure
Support Center for Regulatory Atmospheric Modeling (SCRAM)
Model Clearinghouse (MCH)
Modeling Conferences

Models and Modeling

Licensing and cost
Training
Documentation
Permit Processing
SIP Implementation
Use of the Command Prompt
UnZIP'ing Files
Emissions Data
Land Use and Terrain Data
Meteorological Data
Model Version for later and other Operating Systems (OSes)
Tips for Students and others
Running models
Problems with running models

Unique Questions by Model

AERMET
AERMOD
AERSURFACE
OCD – Offshore and Coastal Dispersion Model questions
TSCREEN questions

Administrative and Other Structures [Back to Top]

Administrative Structure

Q1) What it the relationship of the Air Quality Modeling Group with other groups, divisions, states, etc.?
Q2) How many Regions does EPA have and what are their purposes?
Q3) What is AERMIC?

Support Center for Regulatory Atmospheric Modeling (SCRAM)

Q1) What is the Technology Transfer Network (TTN)?
Q2) What web sites are under the TTN?
Q3) What is the Support Center for Regulatory Atmospheric Modeling (SCRAM)?
Q4) What types of models are on SCRAM?
Q5) What sort of guidance is available on SCRAM?
Q6) How do I report something wrong etc with a SCRAM model, program, or data?
Q7) A link is broken, how do I report it?
Q8) Who updates SCRAM?
Q9) A manual, user’s guide, or other document says to contact a particular person but he or she is no longer there. What do I do?
Q10) Where does the Contact Us page send an email?
Q11) If I do not hear back in 2 or 3 working days from a Contact Us email I sent, how do I contact someone?

Model Clearinghouse (MCH)

Q1) What is the Model Clearinghouse
Q2) How do I submit an issue to the MCH?
Q3) What is the process the submittal goes through?
Q4) Why can I not just submit an issue directly to the MCH Director?
Q5) Who determines the outcome of a MCH submittal?
Q6) What are my recourses if I do not like a MCH outcome?
Q7) How and where are MCH decisions disseminated?
Q8) What is the Model Clearinghouse Information Storage and Retrieval System (MCHISRS)?
Q9) How do I find X on MCHISRS
Q10) How can I narrow my search?
Q11) What is the difference between a Formal, Informal, and Oral record?
Q12) How are the Clarification memos posted?
Q13) How is MCHISRS updated?

Modeling Conferences

Q1) What is a Modeling Conference
Q2) How often are they held?
Q3) Can anyone attend?
Q4) How are conferences announced
Q5) How do I submit a topic, issue, presentation, etc. to a conference
Q6) How are the agendas created and set
Q7) How are issues raised at a conference resolved
Q8) Where can I obtain a copy of the transcript

Models and Modeling [Back to Top]

Licensing and cost

Q1) What is the copyright status of our models, programs and data?
Q2) What does it cost to purchase your models
Q3) How do the commercial versions of model X differ from the models on SCRAM?
Q4) Does EPA certify, test, or approve third party GUIs (Lakes, Breeze, BEEST, etc.)?

Training

Q1) Does EPA offer training?
Q2) Who else offers training?
Q3) Is the Air Quality Modeling Group able to offer ad hoc training?
Q4) Where can I find the meaning of various acronyms used by EPA?

Documentation

Q1) What formats are your documents stored in?
Q2) I can’t read a manual. Where can I get a readable/working copy
Q3) What is a WP, WPF, or WPD format?
Q4) I need help in downloading documents. Can you help?
Q5) Where can I find the Current Memos and the Generic/Recurring Issue me?
Q6) I see the AERMOD Addendums but where are the original documents?
Q7) Where can I find documentation for the ISD meteorological data format?

Permit Processing

Q1) How do I go about getting my business permitted by the EPA?
Q2) Can I do the modeling myself?
Q3) What if I am over some standard?
Q4) What model(s) should I use?

SIP Implementation

Q1) What is a SIP
Q2) How is a SIP constructed?
Q3) Who approves a SIP?
Q4) What happens if my business is affected by a SIP? How can I appeal?

Use of the Command Prompt

Q1) How come EPA models have to be run from the Command Prompt instead of Windows Explorer?
Q2) What is DOS and what are DOS commands?

UnZIP 'ing Files

Q1) Where can I find a copy of pkunzip or a similarly good unzipping program?
Q2) How come PKUNZIP and models won’t work or work right with Window Explorer?
Q3) I unzipped one of your ZIP files and found more ZIP files. What happened?
Q4) I am having problems unzipping a file. What is going wrong?
Q5) Can I use pkunzip on a “gz” or “tar” file? ?”no”

Emissions Data

Q1) Where can I obtain emissions data for?
Q2) How can I get Speciate data to run with CMB?
Q3) Where can I go to find emissions for generic type industries?
Q4) Does AERMOD allow for **negative** emissions to account for offsets or credits?

Land Use and Terrain Data

Q1) Where can I obtain terrain data?
Q2) Where can I obtain land use data?

Meteorological Data

Q1) What meteorological data do I need in order to run EPA Gaussian air dispersion models such as AERMOD, CALPUFF, etc.?
Q2) Where can I obtain the latest 5 years of hourly surface data for a particular station?
Q3) Where can I obtain older surface and upper air data?
Q4) Where can I find documentation for the ISD meteorological data format?
Q5) What radiosonde data do I need for my meteorological preprocessor?
Q6) Where can I obtain the latest radiosonde data?
Q7) What data radiosonde data goes with what preprocessor?
Q8) How do I use the current ISD data with your older models such as CAL3QHCR?

Model Version for later and other Operating Systems (OSes)

Q1) Can I run all the SCRAM models under Linux, the latest Windows 64-bit OS, etc.?
Q2) Is there a way to run these older programs under Windows 7, x64?
Q3) Will model x run in [blank] OS?
Q4) How can I recompile model X for ______ Y operating system (OS)?
Q5) When will we upgrade/compile/recompile our models for Y OS?
Q6) What models are compatible with Windows x64?
Q7) Can I offer EPA a model or utility for SCRAM?
Q8) How do I submit my model for EPA approval?

Tips for Students and others

Q1) Where do I start? I am so overwhelmed!!!

Running models

Q1) How do I run or execute model X?
Q2) What are DOS commands?
Q3) How do I execute a Command Prompt window?
Q4) Do you have a package to plot data, read files, or generate input?

Problems with running models

Q1) My execution window opens and closes in a flash. What is happening?
Q2) I get an error message that model X can not find file Y
Q3) Model X indicates that the program is missing files.
Q4) Windows is reporting a run-time error message. How can I find its meaning? What should I do to correct the problem?
Q5) Is there a multi-core version of model X?
Q6) Requesting more information on a Keyword or technique
Q7) What do I do if I have a problem with model X or data Y?
Q8) What do I do if I have a modeling issue that is not common?
Q9) How do I model tanks with BPIP?
Q10) I am having problems with numerical fidelity with later versions. How do I report it?
Q11) I’m running your model in country Y. It won’t run. How come?
Q12) I’m trying to run TSCREEN, OBODM, etc. How do I do it with x64 OSes?
Q13) I’m using data from vendor x. How come program or data Y from SCRAM won’t run?
Q14) How do I report a problem?

Unique Questions by Model or Processor  [Back to Top]

AERMET

Q1) Do I still need to set the sunrise and sunset times?
Q2) If I do not have land use data, how can I run AERMET?
Q3) Where can I find documentation for the ISD meteorological data form?
Q4) My met data has a lot of missing cloud cover data. What should I do?
Q4) What do I enter into AERMET if I cannot run AERSURFACE?
Q6) How do I adjust AERMET for my country?

AERMOD

Q1) Does AERMOD allow for **negative** emissions to account for offsets or credits?

AERSURFACE

Q1) If I do not have land use data, how can I run AERMET?
Q2) I live overseas and the USGS data site does not have data for my country. How do I run AERSURFACE?
Q3) Where can I get AERSURFACE substitute data for AERMET?

OCD – Offshore and Coastal Dispersion Model

Q1) I downloaded the OCD code and executable from the EPA web site. It appears that the GUI for the OCD model is not in the OCD code.
Q2) If I have operational problems with this model, do I call EPA or what replaced MMS?
Q3) MMS is no longer MMS and has been reorganized. Who do I call about programming issues?

TSCREEN

Q1) How come TSCREEN does not work with my 64-bit Operating System(e.g. Windows 7, x64)?
Q2) TSCREEN will execute but cannot find some files. What’s wrong?

Administrative Structure [Back to Top]


Q1: What it the relationship of the Air Quality Modeling Group with other groups, divisions, states, etc.?

A: AQMG is a group under the Air Quality Assessment Division under the Office of Air Quality Planning and Standards (OAQPS) of EPA. The Air Quality Modeling Group (AQMG) is responsible for EPA's air dispersion models and modeling guidance. Within this group resides the SCRAM web master and a person designated to be the Director of the Model Clearinghouse who is also responsible for the contents of the Model Clearinghouse Information Storage and Retrieval System (MCHISRS).

Q2: How many Regions does EPA have and what are their purposes?

A: EPA is divided into 10 Regions. Each Region has its own Regional Modeling Center. The purpose of these centers is to interact with their respective State's Modeling Centers. This link: /ttn/scram/guidance_cont_regions.htm provides a handy map to visually see each of the Regions. Click on a Region of the above map to see who the potential contacts are for that Region and their specialty such as Air Toxics or Permit Modeling. These regional centers are not under OAQPS but the centers interact with AQMG to discuss and agree upon modeling related issues.

Q3: What is AERMIC?

A: AERMIC is a joint committee that was formed at the behest of the American Meteorological Society to interact with the EPA on developing the next generation of air dispersion model(s). The committee consists of a number of scientists who understand air dispersion modeling and want to improve them. They formed an advisory board to help spur the development of AERMOD. They meet when needed.

Support Center for Regulatory Atmospheric Modeling (SCRAM) [Back to Top]


Q1: What is the Technology Transfer Network (TTN)?

A: The TTN is a collection of technical web sites containing information about many areas of air pollution science, technology, regulation, measurement, and prevention. For a more complete description of each site, see Basic Information.

Q2: What web sites are under the TTN?

A: A complete list of web sites under the TTN can be found at: https://www.epa.gov/ttn/direct.html

Q3: What is the Support Center for Regulatory Atmospheric Modeling (SCRAM)?

A: The Support Center for Regulatory Atmospheric Modeling (SCRAM) is a website under the TTN. It is a source of atmospheric dispersion (air quality) models and information on modeling that supports regulatory programs required by the Clean Air Act.

Q4: What types of models are on SCRAM?

A: SCRAM is mainly a dissemination web site for Gaussian air quality dispersion models. These types of models form most of our Preferred/Recommended, Alternative, and Screening models. We do have links to photochemical models and their support sites as well as Receptor models used to quantify source contributions at receptor (monitor) locations.

Q5: What sort of guidance is available on SCRAM?

A: Guidance can take the form of the Guideline on Air Quality Models (GAQM) which is also referred to as Appendix W. It is located under the Permit Modeling Guidance. There is a list of Clarification Memos link that provides access to memoranda issued by EPA as clarifications of Appendix W and technical aspects of dispersion modeling in general. State Implementation Plan (SIP) Attainment Demonstration Guidance provides guidance documents to EPA Regional, State, and Tribal air quality management authorities and the general public on how to prepare attainment demonstrations for National Ambient Air Quality Standards (NAAQS) and the Regional Haze Rule using air quality modeling and other relevant< technical analyses. There are other guidances in that area on Dispersion Modeling in Urban Areas, Toxics Guidance, the Model Clearinghouse Information Storage and Retrieval System, and documentation for each model.

Q6: How do I report something wrong etc with a SCRAM model, program, or data?

A: Please contact us through the SCRAM Contact Us page. Please describe what you have found and possibly provide a link. In some cases we would like to see you input data and optionally, output files. In some cases, vendor supply their data in their own formats that interact with their GUIs. We have found some of those formats to be incompatible when directly fed into a SCRAM model. Our firewall strips emails of PDF, ZIP, EXE, COM, and other similar files as they have been know to carry malware. Generally, we will request data you rename such file extensions such as PDF to PFD and ZIP to ZPI.

Q7: A link is broken, how do I report it?

A: Please contact us through the SCRAM Contact Us page. If this link is broken, please leave a message with our secretary at (919) 541-5561.

Q8: Who updates SCRAM?

A: We have a designated Web Master who is part of our Air Quality Modeling Group. The Contact Us page link is addressed to the Webmaster but the emails go to his designate for answering general inquiries.

Q9: A manual, user’s guide, or other document says to contact a particular person but he or she is no longer there. What do I do?

A: Use the SCRAM Contact Us page as if that person was still in our group. The person who receives your email will know how to handle your inquiry so please provide enough information that the person here can get right to the issue.

Q10: Where does the Contact Us page send an email?

A: The Contact Us link is addressed to the Webmaster but the emails go to his designate for answering general inquiries.

Q11: If I do not hear back in 2 or 3 working days from a Contact Us email I sent, how do I contact someone?

A: Please place a call to the AQMG secretary at: (919) 541-5561 or the Group Leader at (919) 541-5562. There is usually a reasonable explanation for us not answering right away. This can include, dropped or missed email, the person is out sick and the webmaster did not relink the html page, etc. We make every effort to respond to (or acknowledge) inquiries the day we receive them.

Model Clearinghouse (MCH) [Back to Top]


Q1: What is the Model Clearinghouse?

A: The Model Clearinghouse is a focal point for interpretation of modeling guidance in specific regulatory applications. The Model Clearinghouse is the mechanism by which an EPA Regional Office can obtain EPA Headquarters concurrence on resolving implementation issues and non-regulatory applications related to regulatory air quality modeling. Archival of Model Clearinghouse decisions are located in the Model Clearinghouse Information Storage and Retrieval System (MCHISRS). In addition to MCHISRS, EPA issues formal "Clarification Memos" for general issues related to permit modeling under Appendix W, as appropriate. The statutory authority of the Model Clearinghouse is provided within 40 CFR, Part 51, Appendix W, Section 3.3(b). This section states that "The Regional Office should always be consulted for information and guidance concerning modeling methods and interpretations of modeling guidance, and to ensure that the air quality model user has available the latest most up-to-date policy and procedures. As appropriate, the Regional Office may request assistance from the Model Clearinghouse after an initial evaluation and decision has been reached concerning the application of a model, analytical technique or data base in a particular regulatory action." Public access to policy-related memoranda are available from the "Title V, NSR/PSD Policy and Guidance Database", courtesy of EPA Region 7. This policy-oriented database provides an excellent compliment to the technical-oriented information within MCHISRS.

Q2: How do I submit an issue to the MCH?

A: The need for a Model Clearinghouse action begins when there is an unresolved regulatory modeling issue that arises at a State or local office in a particular permitting action that is then forwarded to the Regional Office (RO) for resolution. After the State/local agency contacts the RO, the Model Clearinghouse (MC) process is initiated to resolve the issue and involves the following steps:

  1. Regional Office makes a determination that the issue is a precedent-setting decision or may have national implications.
  2. Regional Office submits a formal memorandum (on RO letterhead) detailing issue and proposed solution for concurrence to MC Director (via email), along with supporting technical and related documentation.
  3. MC facilitates review across the Regional Office and EPA Headquarters to determine appropriateness of proposed solution.
  4. After review, MC generates a formal memorandum of findings (on EPA letterhead) and submits to Regional Office.
  5. MC Director sends formal MC memo via email to all ROs and archives in MCHISRS for public access and reference.
Questions about the Model Clearinghouse should be provided to George Bridgers, the MC Director.

Q3: What is the process the submittal goes through?

A: Initial inquiries go through the State or Local government modeling contact. Any attempt to circumvent this process, the inquirer is redirected to the State and Local government modeling contact. What is submitted can sometimes be processed by a more local contact.

Q4: Why can I not just submit an issue directly to the MCH Director?

A: We want to resolve the issue at the lowest level of expertise possible. This does two things: 1) it lets the local or more local contact know of the problem, 2) it allows upper levels to work on more complex issues.

Q5: Who determines the outcome of a MCH submittal?

A: The Director of the Model Clearinghouse consults with a number of people and draws varied opinions from different and knowledgeable sources. The outcome is a consensus on the right or proper way to resolve the issue(s).

Q6: What are my recourses if I do not like a MCH outcome?

A: There are legal avenues and appeals to upper levels of EPA management.

Q7: How and where are MCH decisions disseminated?

A: Decisions are written in the form of an EPA Memorandum. The memorandum is sent to the Regional Modeling Contacts in all 10 Regions. The memo is converted to PDF and becomes a formal record of the Model Clearinghouse Information Storage and Retrieval System (MCHISRS)

Q8: What is the Model Clearinghouse Information Storage and Retrieval System (MCHISRS)?

A: The Model Clearinghouse Information Storage and Retrieval System (MCHISRS) is an electronic data base system designed to help the Model Clearinghouse manage information about referrals from the EPA Regional Offices involving the interpretation of modeling guidance for specific regulatory applications.

Q9: How do I find X on MCHISRS?

A: MCHISRS’ main search screen is located at: http://cfpub.epa.gov/oarweb/MCHISRS/index.cfm?fuseaction=main.search Although it is not overtly obvious, the MCHISRS’ search screen is divided into two parts. The upper part consists of a Text Search engine where each record can be search for a certain word or group of words. The word can be in the Record Title, Comment field or the Memoranda area. MCHISRS will search for that word or group of words and display the records in the form of a list where each line has the MCHISRS’ record number (e.g. 88-X-02) and the title of the Record (e.g. Oregon Grid Model – Sept 87). By clicking on the Record No., the user brings up that particular record. There are variances in how things are spelt or spelled . PM10 might be spelt PM-10, pm10 and pm-10. Searches are case insensitive but leaving or ignoring punctuation during a search was not included in the search algorithms. So if you are looking for PM-10, you might want to consider a search with a dash (e.g. PM-10) and one without a dash (e.g. PM10). This may be rectified later. The lower part of the search screen contains a number of filters. Each MCHISRS’s Record has a number of tags included with its Record. For instance, the above Record has an “OR” tag for the State of Oregon and inserted into its States field. In the search screen, the States list box can be dropped and the “OR” filter activated. When the Search button is pressed, every MCHISRS’ Record that has OR in its States field will be selected. Those that do not have the “OR” (Oregon) tag will not be selected. Several filter items can be selected for each list box.

Q10: How can I narrow my search?

A: See the above answer to the previous question.

Q11: What is the difference between a Formal, Informal, and Oral record?

A: A Formal record contains a response in one of its Memorandum (–a) that has a direct bearing on modeling techniques, guidance, and/or policies. This can be whether to include or not include an area for downwash consideration that is outside the 5L distance from a structure but within the Structure Influence Zone. It can also define: “ What is Ambient Air?” An Informal record contains information that may lead to a Formal record or policy decision. These records provide historical background to the interaction between the MCH, the Regions, States, and outside entities. An Oral record is generally equated with a note of little importance, a summary of a telephone call or conference, or the transmittal or receipt of an item. Contents of an Oral record generally have little to no bearing on any Formal actions. They could be deleted and not be missed.

Q12: How are the Clarification memos posted?

A: Each Clarification memo stored on MCHISRS has its own record number with the word "CLAR" in its record number (e.g. 11-CLAR-01). In a search for clarification memos, the Clarification filter in the Subject pull down list box can be clicked on to select that filtering feature.

Q13: >How is MCHISRS updated?

A: After a consensus has been reached and a Model Clearinghouse memo written and signed, the MCHISRS Administrative Person (MAP) works with the MCH Director to create a new MCHISRS record. The MAP creates the html code and sets the tags in the various search list boxes. Once approved, the MAP sends the appropriate and PDF files to the SCRAM Web Master for upload. The MAP then adds the html code to MCHISRS and saves the database. At this point, the new record should be visible to the general public.

Modeling Conferences [Back to Top]


Q1: What is a Modeling Conference?

A: As required by Section 320 of the Clean Air Act, modeling conferences are required to take place approximately every three years to standardize modeling procedures, with special attention given to appropriate modeling practices for carrying out programs PSD (42 U.S.C. 7620). These conferences serve as the forum for receiving public comments on Guideline proposed revisions.

Q2: How often are they held?

A: They are supposed to be held once every three years but there are several instances where they were held approximately four years apart.

Q3: Can anyone attend?

A: These conferences are open to the General Public and especially to anyone who has an interest in air dispersion modeling.

Q4: How are conferences announced?

A: The conferences are formally announced through a Federal Register Notice. Here is a link to the Federal Register Notice announcing our 10th Modeling Conference:

https://www.federalregister.gov/articles/2012/01/31/2012-2026/conference-on-air-quality-modeling

And on SCRAM: /ttn/scram/10thmodconf/EPA-HQ-OAR-2012-0056-0001.pdf

Q5: How do I submit a topic, issue, presentation, etc. to a conference?

A: Instruction for submitting material for a conference are detailed in the Federal Register Notice. Here is a link to a Federal Register Notice announcing our 10th Conference on Air Quality Modeling that was help on March 13-15, 2012:

https://www.federalregister.gov/articles/2012/01/31/2012-2026/conference-on-air-quality-modeling

Q6: How are the agendas created and set?

A: Agendas are a collaboration within AQMG, upper management, Regional, State, and Local Modelers, representatives of affected industries, consultants, and interested parties. Final decisions rest within EPA.

Q7: How are issues raised at a conference resolved?

A: Each Modeling Conference has a court reporter recording everything that is said and transcribing the minutes of the conference verbatim. Copies of the transcripts for the 10th Modeling Conference are available from SCRAM. Here is a link to the transcripts on SCRAM: /ttn/scram/10thmodconf.htm.

Issues are raised during the conference and are captured by the transcript. Comments and material can also be submitted to the Federal Docket. There are deadlines for submittals. We review the transcripts and all submitted comments for issues. We are required to address each issue and generate a response that is then published. Issues are worked on until resolved.

Q8: Where can I obtain a copy of the transcript?

A: Copies of the transcripts for the 10th Modeling Conference are available from SCRAM. Here is a link to the transcripts on SCRAM: /ttn/scram/10thmodconf.htm.

Models and Modeling [Back to Top]


Licensing and cost [Back to Top]


Q1: What is the copyright status of our models, programs and data?

A: All of our models **on** SCRAM are a ”work of the United States government..”. A non-legal explanation can be found here: http://en.wikipedia.org/wiki/Copyright_status_of_work_by_the_U.S._government. Therefore, you can copy the programs, manuals, data, models, etc. without penalty. This is not to be confused with links to other models that are not in the public domain for which you have to “Exit” SCRAM to obtain access to those models. We have links to other models and data that are not EPA models, programs, and data but are owned by others. You will have to make contact with the proper person to determine the copyright status of their material. For instance, CALPUFF was developed by Sigma Research Corporation, a private company, and the model’s ownership may have been transferred via a business transaction. The United States government does not own or have copyright to this model and its documentation. However, through agreements with the owners of CALPUFF, we have secured public access to certain versions with the right for the public to use this model. Further clarifications are on SCRAM and are subject to copyright laws.

Q2: What does it cost to purchase your models, programs and/or data?

A: Everything on our SCRAM web site is free for the download. We have links to other models and data that are not EPA models and data but are owned by others. You will have to make contact with the proper person to determine the cost of their materials.

Q3: How do the commercial versions of EPA models differ from the EPA models on SCRAM?

A: You will have to contact the vendor to obtain an answer from the respective vendor. Any change to our executable programs or data by a vendor null and voids that model or data as being an EPA model or data. Any use of that model is treated as an “Alternative Model” per Appendix W. Our understanding of these commercial packages is that the vendor maintains the integrity of our executables and “wraps” a Graphic User Interface (GUI) around the model. The GUI provides a convenient method for creating data input files, accessing associated files such as meteorological data, and providing a way of saving and viewing output. EPA has generally created the executables but has left GUI development up to the private sector. We do have a few models with GUIs but our practice has been to husband our resources and create GUIs only when necessary or where an acquired model already came with a GUI.

Q4: Does EPA test, approve, or certify third party versions of our models (e.g. Lakes Environmental, Breeze, Beest, etc.)?

A: EPA does not have the resources to test, approve, nor certify models claiming to perform as one of our models. It is up to the user to determine whether or not these vendor created programs perform as advertised.

Training [Back to Top]


Q1: Does the EPA offer training?

A: EPA sponsors the APTI Learning Management System where courses are offered on various aspects of air pollution modeling, guidance, monitoring, and enforcement at various locations nationwide. Further information is available from their web site.

Q2: Who else offers training?

A: There are a number of schools, universities, and commercial companies that offer various courses on air pollution and air quality dispersion modeling. We can not and do not endorse any non-EPA training. However, a search on the internet can reveal a number of such teaching entities

.
Q3: Is the Air Quality Modeling Group able to offer ad hoc training?

A: The Air Quality Modeling Group does not have the time nor the resources to do training per se.
However,
  1. ) we are involved in updating material for the Air Pollution Training Institute,
  2. ) we do make time to answer questions, and
  3. ) we have to stop if the questions appear to be more like training than resolving an air quality modeling issue or confusion about a set of instructions or procedures.

Q4: Where can I find the meaning of various acronyms used by EPA?

A: EPA had created a “Slang Dictionary”. It was replaced by this list of AQSAcronyms.pdfAcronyms and Definitions PDF: https://www.epa.gov/ttn/airs/airsaqs/manuals/AQSAcronyms.pdf.

Various groups have added acronyms definitions to their various documents.
Here are a couple of examples:
  1. https://www.epa.gov/superfund/sites/rods/fulltext/r0298053.pdf - Chapter VI
  2. http://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/termsandacronyms/search.do
  3. https://www.epa.gov/airtrends/acronyms.html
These lists are nowhere near complete. If you come across an acronym without a nearby or earlier definition, please email the acronym along with a link and/or name of the document where you found the acronym via the SCRAM Contact Us page.

Documentation  [Back to Top]


Q1: What formats are your SCRAM documents stored in?

A: In the distant past, our documents were typed and placed in folders. Over time, many of these older documents have disappeared. Efforts have been made to find and scan these older documents and to place them into Adobe PDF format. The documents for the most part, have not been run through an Optical Character Recognition (OCR) process. We find that an OCR process is very good but not perfect. Since we have not had the time and priority to review documents that have gone through an OCR process, we have left these earlier documents in a graphics only form under the PDF format standard. In other words, when an area of a PDF is highlighted and cut, the pasted object is a picture of the text and not the text itself.

We have also generated files using DOS based versions of WordPerfect, Lotus 1-2-3, Freelance, and other programs that were popular during the Windows DOS, Windows for Workgroups, and Windows 98 eras. Most, but not all of the documents generated under these older programs have been scanned to an Adobe PDF format or were converted to new formats such as Word and Excel. The documents that were created with programs such as Word and Excel have been processed through Adobe Acrobat to generate PDF formatted files. Word documents under this process have retained their text. Therefore, when a graphical image in a PDF file is selected, the underlying text represented by that graphical image can be copied and pasted to other documents. The result is actual text that a Spell Checker can recognize. We have used other software packages such as Golden Software’s Surfer and Grapher to generate figures for our documents. The extensions for these formats are srf and grf. Both programs work with the Excel format xls. Often the output is cut and pasted into our documents and you are not likely to see this format on SCRAM. File extensions of dat, inp, out, met, txt, rme, etc. are ASCII text formats. The bin file extension indicates a binary file format. Binary file formats tend to be compact but not easy to read. You have to know the program write statements that were used to generate the file in order to easily decode its contents. If you have problems with a file format, please email us through our SCRAM Contact Us page.

Q2: I can’t read or find a manual. Where can I get a readable/working copy?

A: Many of our documents are stored on a server at the National Service Center for Environmental Publications (NSCEP) and can be downloaded in PDF, Multipage TIFF, or Unformatted Text formats. Online access to this service is through this link: https://www.epa.gov/nscep/ As an alternative, you might also want to try to find the document through one of the internet search engine (e.g. Google). Sometimes it is faster finding a NSCEP stored document this way. If you still cannot find the document, please email us through our SCRAM Contact Us page.

Q3: What is a WP, WPF, or WPD format?

A: A long time ago, WordPerfect was our Agency’s defacto word processor. WPF and WPD are the file extensions often seen on our older documents. The newer version of Word and Libre Office are not able to read these formats. However, many of these documents reside at the National Service Center for Environmental Publications (NSCEP) and can be downloaded in PDF, Multipage TIFF, or Unformatted Text formats.

Q4: I need help in downloading documents. Can you help?

A: In some very rare circumstances, a person may not be able to download a document from an EPA web site. We do not know why this happens but when it does, please email us through our SCRAM Contact Us page. We have been able to help in the past.

Q5: Where can I find the Current Memos and the Generic/Recurring Issue memos?

A: Many of these memos reside on MCHISRS but are not currently identified as such. We are in the process of reviewing each memo for relevancy.

Q6: I see the AERMOD Addendums but where are the original documents?

A: The original User Guide is part of the Addendum package. You may want to reread the README file that accompanies the ZIP file package. Pertinent passages and sections in the Under Revision User’s Guide are being reviewed and transferred to a newer User’s Guide. The Addendum has the latest and corrected Keyword input formats, etc.

Permit Processing  [Back to Top]


Q1: How do I go about getting my business permitted by the EPA?

A: We suggest contacting your State or local Modeling Contact. We provide contact information at: /ttn/scram/guidance_cont_states.htm . Some States have local governmental organizations and they are listed there.

Q2: Can I do the modeling myself?

A: If you know or want to learn how to do it yourself, there is no law stopping you from doing so. However, there are a number of consultants who are likely familiar with what you want to do and who know the permitting process. They likely have an internet presence. A State or local Agency may be able to help.

Q3: What if modeling shows that my industry is over some standard?

A: A consultant may be able to suggest ways for you industry to reduce its emissions.

Q4: What model(s) should I use?

A: We would suggest you read Appendix W. Models are listed and their purposes are described.

SIP Implementation  [Back to Top]


Q1: What is a SIP?

A: is a United States state plan for complying with the Federal Clean Air Act, administered by the Environmental Protection Agency.

Q2: How is a SIP constructed?

A: The SIP consists of narrative, rules, technical documentation, and agreements that an individual state will use to clean up polluted areas.

Q3: Who approves a SIP?

A: A States’ SIP is approved within EPA.

Q4: What happens if my business is affected by a SIP?

A: That business will be required to reduce emissions. This may mean the use of scrubbers, cleaner fuel, taller stacks, and other methods for cleaning up emissions

Q5: How can I appeal?

A: Appeal generally take the form of a lawsuit against the EPA.

Use of the Command Prompt  [Back to Top]


Q1: How come EPA models have to be run from the Command Prompt instead of Windows Explorer?

A: The EPA models are compiled with standard compilers that have an underlying DOS foundation. It would add another layer of complexity if we were to design our models to run from a Window.

Q2: What is DOS and what are DOS commands?

A: DOS is an acronym that stands for Disk Operating System. It was created before the Windows Operating Systems were created. To do anything, DOS commands had to be invoked. Programs had to be executed at the DOS prompt (now the command prompt in the Command Prompt window). More information can be found at: http://en.wikipedia.org/wiki/DOS

DOS commands were executed to perform various routine functions such as moving and copying files, formatting drives, checking the integrity of data on disk systems. A list of DOS commands can be found at: http://en.wikipedia.org/wiki/List_of_MS-DOS_commands along with an explanation of each command and various attributes for tailoring the command for sub-functions such a verifying that copied files exist verbatim in another subdirectory. We still use DOS commands when moving and moving files from one subdirectory to another or using the FC command to verify that a user’s run of a test “matches” the output of the original test case.

Some people do all their subdirectory creation and file moving in Windows Explorer and then bring up the Command Prompt to run their execution.

UnZIP 'ing Files [Back to Top]


Q1: Where can I find a copy of pkunzip or a similarly good unzipping program?

A: Pkunzip can be downloaded from: https://www.epa.gov/ttn/tools.html. This same URL provides a link to the WINZIP web site.

WINZIP is a commercially created product. In the past, they have provided a free trial version.

Other unzipping programs and products are available from the internet. Some may require a purchase of that product.

Q2: How come pkunzip does not run completely from Windows Explorer?

A: Pkunzip is DOS based and pkunzip is available from: https://www.epa.gov/ttn/pkunzip.exe. When it runs from Windows Explorer, the program opens immediately in a Command Prompt (DOS) window displaying its Help screen. The unzipping part of the program cannot be executed from this window. Pkunzip has to exit from this help screen Command Prompt window and the program has to be re-executed from different Command Prompt window.

Q3: I unzipped one of your ZIP files and found more ZIP files. What happened?

A: In some cases, documentation for one model may apply to another similar model. Such is the case with CAL3QHC and CAL3QHCR. This occurs where the models are very similar and the documentation for one model complements or supports the model and or documentation of the other model. Both the user’s guides for CAL3QHC and CAL3QHCR are compressed by using PKZIP or WinZip and then zipped again to from one zip file. The content of one User’s Guide is useful in understanding the underlying physics of the other model. Both share similar input file structures where the input from one file can be slightly modified to create the input for the other model. Therefore, it is convenient to store both users’ guides together. We did the same for the source code.

In the case of CAL3QHC and CAL3QHCR User’s Guides, unzip the main package and then unzip each guide.

Q4: I am having problems unzipping a file. What is going wrong?

A: Pkunzip is DOS based and does not run well from Windows Explorer and ** should only be run from a Command Prompt**. WinZip does run well from Windows Explorer and will open up a separate Windows GUI for unzipping and extracting files to user selected subdirectory.

In the past, we have had reported problems with third party unzipping programs. Therefore, we have recommended use of pkunzip and WinZip. These are two programs that have not given us any reported problems. However, we do not want to discourage the use of third party unzipping programs. The software writers, through the evidence of newer versions, are fixing their codes and/or enhancing features. It has been awhile since we have heard of a third party unzipping program causing problems.

There are very rare instances where the transmission of the download becomes corrupted. The solution is to redownload the file.

Q5) Can I use pkunzip on a “gz” or “tar” file? ?

A: The simple answer is: ”no”. PKUNZIP is purely a Windows program and gz and tar are Unix file compression formats.

Emissions Data  [Back to Top]


Q1: Where can I obtain emissions data?

A: There are two general sources of emissions: natural and man-made. The natural sources can be from vegetation such as Oak trees, entrainment of dust from strong winds, sulphur compounds from volcanos, methane from warming permafrost bogs, etc. Some of these emissions have been quantified and are available with the CMAQ model. It would be best to go to the CMAS site at: http://www.cmascenter.org/ to obtain information and data.

Man-made emissions can be from industrial sources, vehicles, etc. When a company wants to build a plant and that plant will emit pollutants in significant quantities that company has to secure a Permit from the EPA. In that Permit, the company has to quantify the maximum emissions it will generate. That Permit is a source of emissions data. Plant and source parameters should also be available from the Permit.

Vehicle emissions, commonly called mobile source emissions, need to be modeled under certain circumstances. Information and vehicle emissions models and inventories are available from or through: https://www.epa.gov/otaq/models/moves/index.htm

Additional information on emission inventories, Factors, modeling, and an Emissions Monitoring Knowledge Base are available from the CHIEF web site at: https://www.epa.gov/ttn/chief/.

Q2: How can I get Speciate data to run with CMB?

A: This is tricky and not very straight forward. Please email us through our SCRAM Contact Us page.

Q3: Where can I go to find emissions for generic type industries?

A: On the CHIEF web site mentioned above, there is a section of the web site that provides ways and means of determining emission factors. The main page is located at: https://www.epa.gov/ttn/chief/efpac/index.html.

Q4: Does AERMOD allow for **negative** emissions to account for offsets or credits?

A: AERMOD currently does not allow the use of negative emissions to explicitly account for emission offsets or credits with the PVMRM or OLM options for NO2. This is due to the fact that these non-default options have not been sufficiently evaluated to be considered as refined options, and are considered to be screening options under current guidance. Screening options are presumed to include some level of conservatism, and therefore such options may overestimate the credit associated with the negative emissions.

Land Use and Terrain Data  [Back to Top]


Q1: Where can I obtain land use data?

A: The AERSURFACE User’s Guide mentions obtaining land use data from the USGS Land Cover Institute (LCI) website: http://landcover.usgs.gov/natllandcover.php. There are additional links and information in the AERSURFACE User’s Guide.

Q2: Where can I obtain terrain data?

A: One degree Digital Elevation Model (DEM) terrain data is available from the USGS at: http://ned.usgs.gov/. The 7.5-minute DEM data may be purchased from the USGS or one of the internet sites noted above. Users should check the USGS website for the current availability status of these data. More details are available from the AERMAP User’s Guide(s).

Meteorological Data  [Back to Top]


Q1: What meteorological data do I need in order to run EPA Gaussian air dispersion models such as AERMOD, CALPUFF, etc.?

A: Anyone who wants to run any of our models will generally need, in part, surface and upper air meteorological data. Surface data is derived from hourly observations made at fixed locations throughout the world. Collected data that are needed to run these models consists mainly of air temperature, cloud cover, wind direction and speed. Additional data such as humidity, precipitation amount, intensity, and type are needed for a few select models and/or situations.

The upper air data is derived from radiosonde balloon launches where instrumented packages transmit back data that are comprised mainly of air temperature, humidity, wind direction and speed.

The AERMOD modeling system requires land use data be processed through AERSURFACE and the output is used as input to AERMET, the AERMOD meteorological preprocessing program.

The types of data collected will vary along with the quality and completeness of the records.

Surface Data

Q2: Where can I obtain the latest 5 years of hourly surface data for a particular station?

A: The latest surface data standard is called the Integrated Surface Data (ISD). ISD (pronounced: ish-D) is a world-wide standard. Data is available from the National Climatological Data Center at: ISD Data CD

The ISD TD-3505 format is read by our latest models such as AERMET and CALMET. The ‘abbreviated’ format for ISD data is not supported.

Q3: Where can I obtain older surface and upper air data?

A: For convenience, this is a copy of a table in the AERMET Addendum User’s Guide indicating the periods when several types of meteorological data format standards were active. That table is reproduced here:

Met Data Format Active Dates
Table 2-2. Format Active Dates
NWS Surface Format Start Date End Date
CD-144 1948 12/31/1995
SCRAM 1/1/1984 12/31/1992
SAMSON 1/1/1961 12/31/1990
HUSWO 1/1/1990 12/31/1995
ISD 1901 Present
TD-3280 --- ---


The CD-144 and TD-3280 data were created in the mid- 1900’s and formed the datasets used in creating the SCRAM based archive of from 1984 to 1992. That archive still exists on SCRAM and can be used with most of our models and screening models.

The SAMSON and HUSWO formats were shorter lived. The SAMSON dataset contains all of the observed data parameters taken at 1st order National Weather Service locations, as well as solar data as provided by the National Renewable Energy Laboratory (NREL). NCDC still provides this data on 3 CDs. Data also includes data collections from Puerto Rico, Guam, and other Pacific Islands.

The HUSWO data set was a collaboration between NCDC and the EPA where EPA contracted with NCDC to create a special CD-ROM disk containing input data for our models. It contained all observed U.S. surface data taken at 1st order National Weather Service locations for 1990-1995. These data **were** a follow-up to the SAMSON data, but do not contain solar data. NCDC used to provide this data on 1 CD. They do not do so any more. NCDC was finding there were an increasing number of organizations wanting NCDC to create special data sets while their budgets were under pressure. HUSWO was one of those special data sets and NCDC has since dropped supplying this type of data. The ISD dataset covers this period.

Integrated Surface Data (ISD) is the latest standard and it is an international standard. ISD data, sometimes abbreviated ISH, ISHD, and ISHWO, is available in the TDDS3505 format. We often refer to ISD data in our EPA documentation as ISHD data where the “H” stands for Hourly. Details on the development of this data base can be found here: http://www.ncdc.noaa.gov/oa/climate/isd/index.php Data is also accessible via this page but there are international commercial use restrictions that must be agreed to before data can be downloaded. The downloader should select the SIMPLIFIED option for our models. Data collected going back to 1901 has been copied into this format.

Q4: Where can I find documentation for the ISD meteorological data format?

A: The ISD data is in the DS-3505 format. The ISD DS-3505 format is read by our latest models such as AERMET and CALMET. The ‘abbreviated’ format for ISD data is not supported by AERMET. When you click go to: < href="http://www.ncdc.noaa.gov/oa/climate/isd/index.php">http://www.ncdc.noaa.gov/oa/climate/isd/index.php and click on FTP, the list of data years appear. At the bottom of the list, is a sub list of documents. You can FTP one of the isd-format-document documents in either DOC or PDF formats.

Radiosonde Data

Q5: What radiosonde data do I need for my meteorological preprocessor?

A: There are several meteorological preprocessors used with our programs as mentioned in Appendix W, Guideline on Air Quality Modeling. They are: PCRAMMET, MPRM, AERMET, and CALMET. PCRAMMET and MPRM are used with earlier models such as ISCST while AERMET and CALMET were developed primarily for AERMOD and CALPUFF, respectively. Each model has its own user’s guide and readme file(s). Information on what preprocessor program to use is in those guides.

Q6: Where can I obtain the latest radiosonde data?

A: There are three online sources from which to download data and/or purchase datasets on media.
  1. The Earth System Research Laboratory (ESRL) has an online Radiosonde Database for immediate data download and also has media data sets of radiosonde data available for purchase.

    • a) The online interactive program for downloading worldwide sets of radiosonde data is located at http://esrl.noaa.gov/raobs/.. Data in this inventory is from the year 2000 and is “model-ready”. The original FSL (Forecast System Laboratory) format should be selected.

      b) Non online products are available for purchase on CDs or DVD via this site at: http://esrl.noaa.gov/raobs/General_Information.html ESRL is offering to sell The North American Radiosonde Archive (1946-1996) on 4 CDs and the Global Archive (1994-2010) on DVD. These sets are no longer available through the National Climatic Data Center.

  2. The National Climatic Data Center also has similar function as the ESRL site above. The Integrated Global Radiosonde Archive at: http://www.ncdc.noaa.gov/oa/climate/igra/ provides a link to an online Data Access database where files can be downloaded from archive directories. The files are in ASCII format but this is the raw data.
Q7: What data radiosonde data goes with what preprocessor?

A: AERMET is based on MPRM. AERMET can extract data from several standard NCDC formats. These include the TD-6201 format for upper air sounding data, hourly surface weather observations in the CD-144 format, which is a time-based (i.e., by hour) format, and the TD-3280 format, which is an element-based (i.e., by variable) format for surface data.

Q8: How do I use the current ISD data with your older models such as CAL3QHCR?

A: With respect to surface data input, the first possibility is to use the latest Samson/Huswo datasets even though these are quite old datasets. They are directly compatible with CAL3QHCR via PCRAMMET.

The second possibility is to use the NCDC 3505a (?) (3505 abbreviated) Integrated Surface Data (ISD-Lite) datasets from NCDC. Russ Lee Consulting has a conversion program under his Meteorology hotlink to convert the abbreviated ISD-Lite data from ISD-Lite format to Samson format.

However, we have been running into several issues with the ASOS data that form the basis of the ISD data. The wind speeds are being truncated and then averaged instead of just being averaged. This has an effect on low wind speed values. The other way is in which cloud cover is determined that is not directly compatible with earlier cloud cover standards. Earlier cloud cover reporting was in eights and ISD reporting is now in tenths.

Model Version for later and other Operating Systems (OSes)  [Back to Top]


Q1: Can I run all the SCRAM models under Linux, the latest Windows 64-bit OS, etc.?

A: Some of our oldest DOS based models have problems or will not run under a Windows 64-bit OS. Microsoft must have heard user complaints as we are finding some of our older models that would not run under a 64-bit OS are able to do so after being recompiled or if they are run through a “virtual window”.

SCREEN3 is such an example. Two years ago, after a 32-bit recompile, it would not execute under a Windows 7, x64 OS. Today, after a 32-bit recompile, SCREEN3 will run under Windows 7, x 64. There are a number of 32-bit programs that need to be recompiled. Our priority is low for recompiling some of these older, and mostly superceded or little used programs.

Our later models and programs were written to the latest Fortran Standards. Most of our models can be recompiled for a specific Operating System using a Fortran compiler for that system. Some minor changes may have to be made to the source code. Earlier models and programs usually have needed more extensive changes.

Q2: Is there a way to run these older programs under Windows 7, x64?

A: We are experiencing an increasing frequency of messages and questions surrounding issues with older software packages and Windows 7 (64bit). As companies and agencies upgrade their computers, it is becoming the norm that Windows 7 is the default OS.

For now, there is a solution that should get folks up and running, but it is not a permanent solution. Microsoft offers a free download and add-on to Windows 7 called, Windows Virtual PC. It is basically a Windows XP shell or virtual OS that runs within Windows 7. It should allow older software packages to run as if they were being run within Windows XP. The down side is likely the speed at which applications run. Since the environment is a virtual environment running within the Windows 7 OS, I can imagine that memory management isn't as efficient and things don't run as quickly as if run natively in the OS. Of course, I would suspect that any newer computer hardware and faster processors will make up for much of that slowdown.

Here are some links to pass along:

http://www.microsoft.com/windows/virtual-pc/

http://www.microsoft.com/windows/virtual-pc/download.aspx

All this said, there are some permanent solutions that we're exploring. We have found that many of the older software packages that are problematic under Windows 7 can be "fixed" if they are recompiled with a newer compiler that has both the 32bit and 64bit libraries available. This doesn't mean that the executable becomes a 64bit program... rather, it remains a 32bit executable but has the appropriate libraries to run in a 64bit OS. So, we have been able to go back and take the source code on a couple of programs and simply recompile it with a modern compiler to achieve success. In a few cases, the source code has outstanding complier issues or the compilers now flag issues that were previously not identified or resolved. Thus, the refreshing/recompiling of the source code does require that we perform testing to make sure that the results of the new executable are equivalent to the previous version.

[ We have yet to tackle VISCREEN. I seem to remember that there were some other outstanding issues with VISCREEN to which BOEM and EPA were talking... conversation that has grown cold. I'll talk with a few folks here to see if they have recollection of planned changes or modifications to VISCREEN. If there is any recollection on your end, please send it along... let's reopen the dialogue.

For now, try out the Microsoft Virtual PC... might require administrator assistance to download and install... and let me know if it does the trick for now. ]

Q3: How can I recompile a model for another operating system (OS) other than Windows?

A: There are Fortran compilers for Linux, MacOS, and Unix OSes. It is a matter of finding a compiler that will work for that particular OS.

Q4: When will we upgrade/compile/recompile our models for a particular OS?

A: We are a “Windows shop” and most of our users use Windows or have access to a Windows based computer. We compile our programs for Windows first. These are the programs we upload to SCRAM. We sometimes will compile using a different compiler or recompile for a different OS such as Linux. We keep these other executables in-house for testing purposes.

Q5: What models are compatible with Windows x64?

A: The most recently recompiled programs have been recompiled in 32-bit but we found that they run well under Windows 7, x64. We are recompiling our older programs as we have time.

Q6: Can I offer EPA a model or utility for SCRAM?

A: Generally not. If we need a model, we search the literature for ones that might meet our needs and then we evaluate them or we contract out to have a model developed. We also require that our models be in the public domain.

Q7: How do I submit my model for EPA approval?

A: We do not do individual model testing per se. We do not have the time nor resources to test someone’s model unless we have a need for such a model and then we might test it along with other similar models. The best way to show a model’s capability is to run it against real situations and submit the model’s results to a peer review journal.

Tips for Students and others  [Back to Top]


Q1: Where do I start? I am so overwhelmed!!!

We receive a fair number of inquires from students in a panic over trying to run one of our models for their project. Hopefully these tips will ease your angst and allow you to complete your assignment without consuming a lot of medications.

We do expect you to have read the documentation for the program you are trying to run. There is a tremendous amount of documentation.

IMPORTANT:

As much as we would like to be educators, we can not be tutors. We can try to help you help yourself and maybe answer a question or two to help you over a difficult spot or point you in a direction. We do want you to succeed and this is one of the reasons for this section of the FAQs. If you have reached this point, we think you are on your way to being successful.

A: We are here to help you succeed. Slowly and deeply inhale and then exhale 10 times. Hopefully, this will relax you. When and only when you have completed that assignment should you proceed with the following steps:

To start off, AERMOD is probably the toughest nut to crack. These tips apply to AERMOD but can apply to any one of our other models in general.

We recommend that you start with the Sample Run located half way down on the AERMOD page. Here are handy links:

Installation Guide (Sample Run)

Read Me (TXT, 1KB) - please read this file first
Sample Run Instructions (PDF, 250KB) - detailed installation and execution instructions
Sample Run

Once you have accomplished that. I would download AERMOD and its testcases and try to get them up and running

Links of where to get data are spread out throughout this FAQ. Emissions can be estimated by reading AP-42 located on the Chief website which is a part of the Technology Transfer Network (TTN).

The other major program is AERMET for processing meteorological data. AERSURFACE and AERMAP are also major programs BUT if you do not have access to Land Characteristics data and if your source is on relatively flat terrain, then these two programs are not needed.

AERMET requires some Land Use data but this can be generated manually. Information is located in the AERMET section above.

Buildings can increase the dispersion from sources. There are two programs, BPIP and BPIPPRM. BPIP was created for the ISCST program and BPIPPRM was created for newer models with the PRIME algorithm such as AERMOD. If you do not have access to building dimensions, a program such as Google Earth can be useful.

For instance, Google Earth contains a "ruler" for measuring distances such as from one corner of a building to another. The ruler is selectable from the menu at: Tools | Ruler. Building heights will have to be estimated by comparing length of shadows of the buildings to the length of shadows of common items such as cars, tractor trailers, telephone poles, etc. None of this will be precise but it will allow you to work with the programs to derive reasonable answers.

This should help you to help yourself complete your project. We are here to help you but we are dealing with limited time and resources to devote to your project(s).

Running models  [Back to Top]

Q1: How do I run or execute a model I downloaded from SCRAM?

A: Generally, there are execution instructions with the model’s readme file and/or in the model’s User’s Guide. All models are executed from the Window’s Command Prompt ( Start | All Programs | Accessories | Command Prompt). The older models used to read the input files from the Command Line. The newer and recompiled models read the files by opening them up from within the code. The later makes the models more compatible with other operating systems.

Q2: What are DOS commands?

A: See answer above in the Command Prompt section.

Q3: How do I execute a Command Prompt window?

A: By clicking on these Window buttons in successions: Start | All Programs | Accessories | Command Prompt.

Q4: Do you have a package to plot data, read files, or generate input?

A: We leave most of that up to the vendors who package our models with their GUIs. We generally use commercially available programs such as Excel, Grapher, Surfer, SigmaPlot, etc. and feed our data into one of these commercially available programs.

Problems with running models  [Back to Top]


Q1: My execution window opens and closes in a flash. What is happening?

A: It is likely that you tried to run the program by double-clicking on the executable name in Windows Explorer. All our programs need to be executed from the Command Prompt (Start | All Programs | Accessories | Command Prompt)

Q2: I get an error message that model X cannot find file Y.

A: There are two likely causes. All our models are usually executed with executable and all its needed input file existing in the same subdirectory. The other cause is when a program such as TSCREEN is downloaded and installed, only 3 zip files are installed instead of 4 files. The fourth file in this case is the “documentation “ file which contains two additional files needed to run TSCREEN.

Q3: A model indicates that the program is missing a file or files.

A: There are a number of ways this could happen:

1) All our models are usually executed with the executable and all its needed input file(s) existing in the same subdirectory and one file or more files are missing.

2) A file is misspelled.

3) A file has the wrong extension

4) We switched the model from reading the input files from the Command Line to being opened by the model.

5) Really old models sometimes request a filename and the filename either requires or does not require a period after its last character.

6) In the input file, the input required a file be listed and it was not or it was misspelled.


Q4: Windows is reporting a run-time error message. How can I find its meaning? What should I do to correct the problem?

A: The more current and larger models have error messages and sometimes they are written out to file. The ones with numbered codes also have those codes listed in a section of their User’s guides. The files will echo the error code number and message. Often the file is named: error.out and can be read by a text editor.

Q5: Is there a multi-core version of AERMOD or CALPUFF, etc.?

A: We are working on it but it is not a high priority.

Q6: Requesting more information on a Keyword or technique.

A: There are several manuals being updated. Their addendums have the latest and corrected keywords and information. If you can not find a keyword, feel free to contact us via the SCRAM Contact Us page.

Q7: What do I do if I have a problem with model X or data Y?

A: First try to solve the problem yourself. Look over the documentation . We can help you but we would rather do so after you have tried it yourself. You also may have found a bug and need to report it.

Q8: What do I do if I have a modeling issue that is not common?

A: I would try to have it resolved at the lowest levels first. This may mean starting off with your Local or State Modeling Contact (/ttn/scram/guidance_cont_states.htm ). If they can not resolve the issue, they will send it to a higher level. Please see Model Clearinghouse above for further details.

Q9: How do I model tanks with BPIP?

A: I would check with the State first or EPA Region second for which the modeling is being performed. They may have a preferenece.

Q10: I am having problems with numerical fidelity with later versions. How do I report it?

A: Contact us via the SCRAM Contact Us page.

Q11: I’m running your model in country Y. It won’t run. How come?

A: We ran into this recently. It requires you to change your keyboard from your country to that of the United States. Somehow, the way certain languages are structured, this interferes with the data being read from the input file. It this does not work, please contact us via the SCRAM Contact Us page.

Q12: I’m trying to run TSCREEN, OBODM, etc. How do I do it with x64 OSes?

A: These are very old models and have a 16-bit foundation. Windows 7, x64 will not work with these models. You might try to either find a Windows XP based computer or try to use the Windows VM module. The former will work but we have not tested the later.

Q13: I’m using data from a vendor. How come their data won’t run with the model I downloaded from SCRAM?

A: Some of the vendors will store model input data in a different format that is different from what SCRAM can read. You need to get up with the vendor or download data from the internet.

Q14: How do I report a problem?

A: Please send us a email via the SCRAM Contact Us page.

Unique Questions by Model > [Back to Top]


AERMET  [Back to Top]


Q1: Do I still need to set the sunrise and sunset times?

A: The current version of AERMET will automatically pick the most appropriate standard upper air sounding time (00Z or 12Z) based on the latitude and longitude of the upper station, so there is no requirement or option to specify sunrise/sunset times in AERMET. Ideally, the upper air data should be shortly before sunrise. Beginning with version 11059, AERMET also includes an option to select the most appropriate upper air sounding based on sunrise for the upper air station location. However, this option may result is no acceptable soundings in some cases depending on the location and time of year. These new AERMET options for upper air data are described in Section 2.2 of the AERMET User’s Guide Addendum.

Q2: If I do not have land use data, how can I run AERMET?

A: You can manually specify the surface roughness length, Bowen ratio, and albedo surface characteristics needed in AERMET Stage 3 processing. Although AERSURFACE only supports the use of US National Land Cover Data (NLCD), the tables of surface characteristics by land use category included in Appendix A of the AERSURFACE User’s Guide should be helpful. Additional information regarding specification of surface characteristics for AERMET is provided in Section 3.1 of the AERMOD Implementation Guide, available at the following url:

/ttn/scram/7thconf/aermod/aermod_implmtn_guide_19March2009.pdf

Q3: Where can I find documentation for the ISD meteorological data format?

A: The ISD data is in the DS-3505 format. The ISD DS-3505 format is read by our latest models such as AERMET and CALMET. The ‘abbreviated’ format for ISD data is not supported by AERMET. When you click go to: http://www.ncdc.noaa.gov/oa/climate/isd/index.php and click on FTP, the list of data years appear. At the bottom of the list, is a sub list of documents. You can FTP one of the isd-format-document documents in either DOC or PDF formats.

Q4: My met data has a lot of missing cloud cover data. What should I do?

A: We have heard some reports of issues with missing cloud cover in the ISD surface data for non-US stations. In a few cases we have seen the cloud cover is only reported every third hour. AERMET currently treats hours with missing cloud cover as missing (since it cannot calculate heat flux used in the boundary layer algorithms). The amount of missing cloud cover data may vary from station to station, so you may want to look at more than one location. We are considering options to allow filling in for missing cloud cover data within AERMET, but there’s currently no timetable for when that might happen.

AERMOD  [Back to Top]


Q1: Does AERMOD allow for **negative** emissions to account for offsets or credits?

A: AERMOD currently does not allow the use of negative emissions to explicitly account for emission offsets or credits with the PVMRM or OLM options for NO2. This is due to the fact that these non-default options have not been sufficiently evaluated to be considered as refined options, and are considered to be screening options under current guidance. Screening options are presumed to include some level of conservatism, and therefore such options may overestimate the credit associated with the negative emissions.

AERSURFACE  [Back to Top]


Q1: If I do not have land use data, how can I run AERMET?

A: You can manually specify the surface roughness length, Bowen ratio, and albedo surface characteristics needed in AERMET Stage 3 processing. Although AERSURFACE only supports the use of US National Land Cover Data (NLCD), the tables of surface characteristics by land use category included in Appendix A of the AERSURFACE User’s Guide should be helpful. Additional information regarding specification of surface characteristics for AERMET is provided in Section 3.1 of the AERMOD Implementation Guide, available at the following url:

/ttn/scram/7thconf/aermod/aermod_implmtn_guide_19March2009.pdf

Q2: Where can I find documentation for the ISD meteorological data format?

A: The ISD data is in the DS-3505 format. The ISD DS-3505 format is read by our latest models such as AERMET and CALMET. The ‘abbreviated’ format for ISD data is not supported by AERMET. When you click go to: http://www.ncdc.noaa.gov/oa/climate/isd/index.php and click on FTP, the list of data years appear. At the bottom of the list, is a sub list of documents. You can FTP one of the isd-format-document documents in either DOC or PDF formats.

OCD – Offshore and Coastal Dispersion Model questions  [Back to Top]


Q1: I downloaded the OCD code/executable from EPA website. It appears that the GUI for the OCD model is not in the OCD code.

A: There is a separate program that prepares inputs for OCD. Double-click on OCDMENU.EXE. The following Title page will appear:

Then single-click on the Title page to reveal the main program:

OCD can be run from this GUI. Additional information about this GUI can be found by clicking on the Help menu’s “About OCD” and then clicking on Major Features. There is a paragraph devoted to the general capabilities of this GUI.

Q2: If I have operational problems with this model, do I call EPA or what replaced MMS?

A: EPA will likely respond to questions about its usage with regard to air pollution modeling issues while MMS has responsibility for its programming and internal technical functions and content.

Q3: MMS is no longer MMS and has been reorganized. Who do I call about programming issues?

A: Good question.

TSCREEN  [Back to Top]


Q1: How come TSCREEN does not work with my 64-bit Operating System(e.g. Windows 7, x64)?

A: TSCREEN is a very old program and our users who are on newer 64-bit OSes are experiencing problems. TSCREEN runs okay on XP and earlier versions of Windows.

Also Microsoft has attempted to address issues with older programs running on its 64-bit OSes. Here are the links:

http://www.microsoft.com/windows/virtual-pc/

http://www.microsoft.com/windows/virtual-pc/download.aspx

but there are some caveats such as to the edition of Windows 7 you are using, etc.

Q2: TSCREEN will execute but can not find some files. What’s wrong?

A: Some of the files are part of the Demonstration ZIP file. You need to have downloaded these **4** ZIP files:

TSCREEN Demonstration <-- This is the one that is often missed.
TSCREEN Model, File 1
TSCREEN Model, File 2
TSCREEN Model, File 3

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