U.S. EPA AERMOD Dispersion Model Promulgated on December 9, 2005!

On October 21, 2005, the U.S. EPA Administrator signed revisions to the Guideline on Air Quality Models - Appendix W of 40 CFR Part 51.  These revisions include the recommendation for the replacement of the Industrial Source Complex (ISC3) model with the U.S. EPA AERMOD model.  The revisions were submitted to the Federal Register and published on November 9, 2005.  The AERMOD model, which incorporates the PRIME building downwash algorithm; AERMET, a meteorological data preprocessor; and AERMAP, a terrain data preprocessor, will become the recommended model for assessing criteria pollutants under the Clean Air Act as of December 9, 2005.

Although the EPA recommends a one-year transition period ending on December 6, 2006, we suggest that you contact your regulating authority before proceeding with your AERMOD modeling projects as requirements for implementation may vary by regulatory agency.

It is time to start learning about this new air dispersion model - check out the AERMOD Technical Guide at https://www.weblakes.com/aermodvol1/tableofcontents.html.

In addition, Lakes Environmental is offering a variety of courses to help you understand the AERMOD model - see our list of upcoming courses and register now!

Lakes Environmental Presents The Need for Air Dispersion Modelling at the Conference for Environmental Protection in India

Lakes Environmental is pleased to announce that it will be attending the International Interdisciplinary Conference for Environmental Protection to be held Jan. 7-9, 2006 at Coimbatore Institute of Technology, Coimbatore, India. Mr. Gareth Davis will be presenting the paper The Need for Air Dispersion Modelling. See the conference website at https://www.icstep2006.com/aboutcit.html for the time and location of this presentation.

Mr. Gareth Davis is an Environmental Specialist and the Technical Support Manager at Lakes Environmental Software.

Lakes Environmental will be closed on Friday, December 23^rd; Monday, December 26^th and Friday, December 30^th for the holiday season. We would like to take this opportunity to wish you and your colleagues a safe and happy holiday.

We’ve set a number of training dates for 2005 and 2006, with additional courses to be announced.  Please contact us at training@weblakes.com for international or customized training needs.

AERMOD & ISCST3 Courses

CALPUFF Courses

Customized Courses

Lakes Environmental offers a variety of on-site, customized courses for all of your air dispersion modeling needs.  For information on pricing and availability, please email us at training@weblakes.com.

For more information on these courses, such as registration information and course outlines, please visit our website: https://www.weblakes.com/courses.html.

Specifying an Hourly Emission File in AERMOD

When preparing your air dispersion modeling project using one of the U.S. EPA air dispersion models - ISCST3, ISC-PRIME or AERMOD (the models) - you may be required to model source specific parameters that change over time.  For example, such parameters can be source emissions, stack gas exit temperature or stack gas exit velocity.  This can be accomplished by specifying an Hourly Emission File.

The Hourly Emission File can be created using Microsoft Excel and converted into a text file format for use by the models.  Each record or line of the Hourly Emission File must include the keyword (SO HOUREMIS), followed by the Year, Month, Day, Hour, Source ID, Emission Rate (g/s or user units).  For point sources, the record must also include stack gas exit temperature (K), and stack gas exit velocity (m/s).

The following is an example of what the Hourly Emission Files should look like:

SO HOUREMIS 86  1  1  1  STACK1  145.0  283  9.4
SO HOUREMIS 86  1  1  1  STACK2  150.0  284  9.0
SO HOUREMIS 86  1  1  2  STACK1      0.0  285  9.4
SO HOUREMIS 86  1  1  2  STACK2  120.0      0  8.0
SO HOUREMIS 86  1  1  3  STACK1  120.0      0  9.4
SO HOUREMIS 86  1  1  3  STACK2      0.0   -20  9.4


Hourly Emission File Tips:

1. Only one hourly emission file can be specified for each run.



2. The data must include the exact same dates/time as are included in the meteorological input files.  Failing to have the date/hour match will cause the model run to fail.



3. Source IDs must correspond to the source IDs defined in the SO Pathway and be in the same order.



4. The models will use the stack release height and stack inside diameter defined in the Source Pathway, but will use the emission rate, exit temperature and exit velocity from the hourly emission file.  If these parameters are missing in the file, then the models will consider the missing values as zero.



5. An undocumented behavior of the current version of the models occurs when a project is run using the entire year of met data but the hourly emission file and the met data file do not cover the same period (e.g., met data runs from Jan 1 to Dec 31 and the hourly emission file runs from Jan 1 to Jun 30).  Provided that both files begin at the same date/time, the models will still run; however, the models will use the parameters found in the last record of the hourly emission file throughout the rest of the met period.  For this reason, it is very important that your hourly emission file match the met file specified in your project.


In the AERMOD model, this can be verified by using the AERMOD Model Debugging Output Option (CO DEBUGOPT MODEL) specified in the Control Pathway.  CAUTION: the generated debugging file can be very large!  It is recommended that, when using this option, you limit your project run to a few days in order to inspect the intermediate calculations contained in this file.


6. Gas Exit Temperature Tips:
   • A gas exit temperature equal to 0.0 K for any particular hour indicates to the models that the plume is being released at the ambient temperature specified in the met file.
   • A negative gas exit temperature indicates to the models that the plume has an exit temperature that exceeds the ambient temperature by a fixed amount.  For example, if the ambient temperature in the met data file is 265.9 K for a particular hour and -20 was specified in the hourly emission file for that hour than the models will read the gas exit temperature as 265.9 + 20 = 285.9 K.

We are currently accepting submissions for the Monthly Modeling Tip which appears in our newsletters.  If you have a modeling tip that may benefit a variety of people, please send it to us at support@weblakes.com.   Your name and the name of your organization will appear below the tip providing you with greater exposure.

GHG Regulations Strengthened

The Government of Canada today added six greenhouse gases (GHG) to Schedule 1 of the Canadian Environmental Protection Act 1999 (CEPA 1999).  The addition allows for the introduction later in 2006 and implementation of regulations to ensure large industrial emitters meet their commitments to reduce greenhouse gas emissions by 45 megatonnes by 2008-2012.
https://www.globe-net.ca/search/display.cfm?NID=1539&CID=8

Air Quality in Canada Improving - Report

Air quality in Canada has been improving steadily for the past three decades, according to The State of Urban Air in Canada, a study released today by The Fraser Institute.  The greatest success story has been a 94 percent reduction in the levels of ambient lead since 1974.
https://www.globe-net.ca/search/display.cfm?NID=1533&CID=8

EPA Proposes to Relax Reporting Rules for Corporate Toxic Releases

Companies would report their releases of toxic chemicals every other year instead of annually, and more chemicals would be eligible for less-detailed disclosures under two new proposals announced by the U.S. EPA on October 4.  The agency claims that the initiatives will reduce the burden on companies and help EPA staff improve data quality.  However, officials at some companies, including Dow Chemical Co., say the changes will only modestly affect their bottom lines, whereas state officials complain that the changes are likely to torpedo their pollution-prevention programs.
https://pubs.acs.org/subscribe/journals/esthag-w/2005/nov/policy/jp_toxicrules.html

Distinctive Chicago Chocolate Smell, Pollution to Some, To Disappear

For decades, commuters and tourists have delighted in the mouthwatering smells wafting over the city from the Blommer Chocolate Co. factory.  Now, that aroma is about to disappear, courtesy of federal regulators.
https://enn.com/today.html?id=9327

Study Shows There's More CO2 Now Than Past 650K Years

Scientists are looking back to a time when "greenhouse gases" were not the problem they are today, and it is giving them a clearer picture of how people are making it worse.  A team of European researchers analyzed tiny air bubbles preserved in Antarctic ice for millennia and determined there is more carbon dioxide in the atmosphere now than at any point during the last 650,000 years.
https://enn.com/today.html?id=9325

Here are a few Conferences and Tradeshows coming up in the next few months: