Lakes Environmental Releases ISC-AERMOD View 5.8

Lakes Environmental is proud to announce the release of ISC-AERMOD View™ version 5.8 on October 30, 2007. This version includes several enhancements to the Source Pathway and the implementation of the OLM and PSD source groups. For a more detailed description of enhancements, please see the release notes.

If you are currently in maintenance for ISC-AERMOD View and did not receive an email regarding the update, please contact us at support@weblakes.com.

If you are a user of ISC-AERMOD View but are no longer in maintenance, please contact us at sales@weblakes.com for appropriate pricing information for your maintenance renewal.

CALPUFF Training for the US EPA Office of Pesticide Programs

On November 13 to 15, 2007, Lakes Environmental carried out an advanced CALPUFF air dispersion modeling course in Arlington, Virginia for the members of the US EPA Office of Pesticide Programs. The training was focused on the use of air dispersion models to estimate the concentration of fumigants in the atmosphere. Dr. Jesse Thé, president of Lakes Environmental, was the main instructor for this 3-day training course.

We would like to thank the US EPA OPP for choosing Lakes Environmental for its training needs.

Thanks to the AWMA Golden Empire Chapter

Lakes Environmental and Dr. Jesse Thé would like to thank the AWMA – Golden Empire Chapter for hosting his presentation "The AERMOD model and its application for development and permitting in California" at the dinner meeting on October 18th 2007.

Lakes Environmental at FIMAI Trade Show

Lakes Environmental would like to thank the organizers of the FIMAI trade show in São Paulo, Brazil from October 24-26, 2007 for a successful and well-run trade show. FIMAI is the premier event focused on the Industrial Environment sector in Latin America.

Lakes Environmental would also like to thank Mr. Silvio de Oliveira from SECA, our distributor in Brazil, and Euza de Oliveria for running the Lakes Environmental booth in the Canadian Consulate Pavillion on our behalf. A special thanks to Thais Marini Aun, the Trade Commissioner Assistant who was a tremendous help in setting up our attendance at the show. Information about next year’s FIMAI can be found at https://www.fimai.com.br/.

Sinocan Intellitech Ltd. - Beijing, China

The Chinese government is poised to enforce its new air quality assessment guidelines in preparation for 2008, when Beijing will host the Olympic Games XXIX from August 8 to 24, 2008. Environmental protection is becoming one of the critical issues for this city and for this country.

Lakes Environmental offers a robust and easy-to-use graphical interface for the AERMOD and CALPUFF models, which are among the air pollution dispersion models officially designated by China’s State Environmental Protection Administration (SEPA).

We’ve set a number of training dates for 2008, with additional courses to be announced soon! Be sure to register in advance; spot are limited.

AERMOD Courses

CALPUFF Courses

For more information on the above courses, such as registration information, location, and course outlines, please visit our web site: https://www.weblakes.com/courses.html.

Representing Rectangular Stacks

When modeling the release point of a stack using the US EPA AERMOD or CALPUFF air dispersion models, it is assumed that the release occurs through a circular-shaped stack. In reality, there are instances where the release takes place through a rectangular area rather than a circular one. Since these models require the stack diameter as an input, the modeler must find a way to convert the rectangular dimensions into an effective circular dimension or diameter.

Method 1: Calculating the Equivalent Diameter (D_eq)

As a first approximation, the modeler can calculate the Equivalent Diameter (Deq) of the rectangular stack. The equivalent diameter of a rectangular release is defined as:

Where:

This equation is derived by assuming that the area of the rectangular region
(L x W) is equal to the area of the circular region, where the equation for the area of a circle is the standard Area = Pi * (Radius)2.

Method 2: Calculating the Hydraulic Diameter (D_h)

An alternative method for approximating the circular dimension is the Hydraulic Diameter (D_h). This is defined as:

Where:

Dh =	Hydraulic Diameter
L  =	Length
W =	Width

The hydraulic diameter is a commonly used approximation for representing the flow through non-circular pipes, vents, etc. For a rectangular region, the cross-sectional area A is related to the perimeter P (which is 2L+2W for a rectangle).

Comparison Between Methods

The hydraulic diameter approximation tends to produce smaller values compared to the equivalent diameter. See the example below:

It is important to note that the estimated stack diameters are approximations which are used in the model to calculate plume rise. In reality, there will be differences between plume rise of a circular stack than one of another shape, since a circular stack has a smaller surface area in contact with colder ambient air compared to a rectangular stack, for example. Thus, plume rise from, say, a rectangular stack may be somewhat less (and concentrations higher) than that calculated using the equivalent diameter, resulting in a slight under prediction of concentrations in the model for most situations. For some building downwash configurations, though, the reverse can be true.

US EPA Recommendations

The Equivalent and Hydraulic diameter methods are only two of the most common ways to approximate a rectangular stack using a circular stack diameter. While the US EPA has suggested the use of the Equivalent Diameter method in some communications, there does not appear to be a formal recommendation in the EPA’s guidance. However, EPA regional offices and state agencies may have guidelines on what method to use. Where any doubt at all exists, you should always check with your regulator to ensure that the method you choose falls within any guidelines.

Acknowledgements: This tip was a joint contribution from Lakes Environmental's Modeling and Support Group and Russell Lee from RF Lee Consulting.

Remember: 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.

Map Shows top CO2 Producers in the World

November 15, 2007 - WASHINGTON (AP) -- There's growing worry about global warming, but how much of it is the work of that power plant just outside town? And if Congress limits heat-trapping greenhouse gases, will it affect utility and electric bills? And who's the biggest corporate culprit when it comes to climate change? Answers to these questions may be only a couple of computer clicks away. A new interactive online database unveiled Wednesday provides maps, color-coded categories and detailed information about who is putting 10 billion tons of carbon dioxide into the atmosphere annually from power plants around the world -- about a fourth of it from the United States. The interactive database is available at https://www.carma.org
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Final Climate Change Report Conference Opens

November 12, 2007 - VALENCIA, Spain - The U.N.'s top climate official challenged world policymakers Monday to map out a path to curb climate change, charging that to ignore the urgency of global warming would be "nothing less than criminally irresponsible."

Yvo de Boer issued his warning at the opening of a weeklong conference that will complete a concise guide on the state of global warming and what can be done to stop the Earth from overheating. It is the fourth and last report issued this year by the Intergovernmental Panel on Climate Change, co-winner of this year's Nobel Peace prize.
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Scientists Strive to Pinpoint Warming Forecasts

November 11, 2007 - OSLO (Reuters) - Moving on from the risk of global warming, scientists are now looking for ways to pinpoint the areas set to be affected by climate change, to help countries plan everything from new crops to hydropower dams.

Billion-dollar investments, ranging from irrigation and flood defenses to the site of wind farms or ski resorts, could hinge on assessments about how much drier, wetter, windier or warmer a particular area will become.
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California Sues EPA Over Car Emissions

November 8, 2007 - SAN FRANCISCO (Reuters) - California sued the Environmental Protection Agency on Thursday, demanding a quick federal decision that would allow the nation's most populous state to limit greenhouse gas emissions from vehicles.

"California is ready to implement the nation's cleanest standards for vehicle emissions, but we cannot do that until the federal government grants a waiver allowing us to enforce those standards," Gov. Arnold Schwarzenegger said.
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Ship Emissions Seen Causing 60,000 Deaths a Year

November 7, 2007 - BEIJING (Reuters) - Emissions from ocean-going ships are responsible for about 60,000 deaths a year from heart and lung-related cancers, according to research published on Wednesday that calls for tougher fuel standards.

Shanghai, Singapore and Hong Kong, three of the world's five busiest ports, were likely to suffer disproportionate impacts from ship-related emissions, said the study, published in Environmental Science and Technology, a journal of the American Chemical Society.
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10 Most Polluted Places on Earth

November 1, 2007 - Conservations groups recently released this year's list of the 10 worst polluted placed in the world. Experts from Johns Hopkins University, Harvard University, MIT, Mount Sinai Hospital and other groups devised the listing criteria, which focused on pollution's impact on human health, especially that of children.
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Here are a few conferences and trade shows coming up in the next few months: