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SoundPLAN

SoundPLAN AirPLANs

Introduction toair pollution modeling with

SoundPLAN Air Pollution Modules

Development Headquarters

Braunstein + Berndt GmbH

Etzwiesenberg 15

71522 Backnang

GERMANY

Tel: ++49.7191.9144-0

Fax: ++49.7191.9144-24

www.soundplan.de

International Headquarters

SoundPLAN International LLC

80 E Aspley Lane

Shelton, WA 98584

USA

Tel: +1-360-432-9840

Fax: +1-360-432-9821

www.soundplan.com

Your local distributor:

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2 |Comments

Results of air pollution calculations use a lot of disk

space, making it impossible to create a small demo

project with sensible in- and output for all the Air-

PLAN models and modules. Users want to save time,

too, so they will also simplify project data. Our

demo shows what SoundPLAN does, how to use it,

and how to correctly simplify projects.

Demo projects are stored on our FTP server with

slides and a short project description and a sum-

mary of the results. Download projects and analyze

how we have accomplished different tasks.

Open SoundPLAN in the demo mode in order to have

all air pollution modules available. In this mode you

can do everything except store files. For more exten-sive investigations, order a temporary trial license

from your local distributor. Distributor information is

found at www.soundplan.com.

Rough Estimation or Detailed Analysis?

Remember the three levels of investigation when you begin modeling:

Prediction Dontbe fooled by the illusion that air pollution concentrations can

be exactly foreseen if you were to buy the right calculation model. Such a model

would be too complex to even start from a PC! You will discover that it is nearly

impossible to get the complete data needed for a good prognosis. You must

create scenarios based on a few estimations instead of the many local mea-

surements actually needed for precise work. This makes sense when you con-

sider that forecasting air pollution concentrations cant be easier thanforecast-

ing weather because air pollution dispersion depends, in part, on weather con-

ditions.

Detailed analysis(we call it, fine screening) allows you to simplify a model as

much as needed. However, all that is gained from a simplified scenario is a good

estimation of concentrations. How accurate can a detailed analysis be? You

have to combine complex wind fields and dispersion conditions with a reliable

emission scenario. What if the scenario doesnt work? Is there a simpler way to

get reliable results? Of course! Rough estimation!

Rough estimation(or, rough screening) seems a simple task to beginners who

have unreliable results, but this is not true! Experienced users carefully refine

their tasks and choose rough estimation methods to save calculation time and

win reliability and accuracy. They simplify models in ways that guarantee mod-

erate, but secure overestimations. Using a rough screening model correctly, is

simply not as easy as it seems! Thoughtfully operating outside the borders of

reality requires a lot of skill to read reliable information from the results.

Willlimit values be exceeded?

is a difficult question to answer, even

using a fine screening model for de-

tailed analysis.

The answer yesor norequires

evaluating the probability of error.

This value can be estimated for

measurement based validation

calculations, but not for estima-

tions based on freely defined sce-

narios.

Canexceeded limits be excluded?

is easily answered. A rough estimationis needed for a definitive no answer.

The answer yesis based on a

specific overestimation, so it is re-

liable. Nois not reliable. It re-

quires either an alternate plan or

refinement of input data and finer

screening.

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Rough screening: Gauss(TA Luft86) | 3

GAUSS(TA Luft86)

(German national standard TA Luft 1986-2002)

Gauss was part of the official German standard "TA Luft

86" which was released to estimate the impact of new

industrial air pollution sources, especially high emitting

point sources like smoke stacks. It is a simplified version of

the Gauss model defined in the VDI code3782-1. The vali-

dation is associated to the evaluation of the VDI standard.

It has a tendency to overestimate close to the source.

Gauss models calculate very quickly. That means they can,

and should, handle wind statistics with a very high resolu-

tion. They calculate a plume with a statistical pollutant

distribution for each wind flow situation before evaluating

statistics like mean, max and percentiles.

The German model is not very sophisticated, but it brings

solid results at least for comparable climate zones. We

suggest looking for test data to compare if it fits your re-

gional conditions and requirements.

Because Gauss models are statistical models, use them

only to analyze representative time periods. Dont use

them for single case interpretations.

Rough screening: Austal2000

AUSTAL2000

(German standard TA Luftsince 2002)

In 2002, TA Luft02, which favors a diagnostic wind field

and a Lagrange model to calculate the air pollution disper-

sion, replaced TA Luft 86. The reference model AUS-

TAL2000 (

Dr. Janicke, Dunum, Germany) was developed

for the German Environmental Agency.

AUSTAL2000 has three advantages:

It calculates a wind field which can regard terrain up to

an inclination of 20%

It has the reputation of the German government

It is freeware; you pay only for the SoundPLAN inter-

face.

Austal2000 is very rudimentary, based on ASCII-input-textfiles and ASCII-output-text files. The SoundPLAN interface

allows you to work in a comfortable program environment.

You can apply your experience with the SoundPLAN Libra-

ries, Geodatabase, Calculation Kernel and Graphics, plus

you have full SoundPLAN support for the interface.

Working with freeware does have some disadvantages:

There is no international support for the original AUS-

TAL2000 calculation kernel. SoundPLAN supports you as

much as possible, but as we are not the authors of

AUSTAL2000, our help is limited to our interface.

You have no claim on reparations if AUSTAL2000 doesnot work or produces implausible results.

The results are limited to the German/European require-

ments. If your national standards are more restrictive or

require additional statistics, Austal2000 isnt suitable.

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4 |Fine Screening: MISKAM

When we talk about fine screening, we talk first about calculating wind fields which can include turbulent

effects between buildings. Then we talk about the spreading based on these precalculated wind fields. That

means we need three dimensional grids with high resolution in x, y, AND z directions, which are calculated

from the ground to a height far above the rooftops. MISKAM and AUSTAL2000 have different wind field

models and also different pollution dispersion equations and are therefore used for different prognosis.

MISKAM(Dr. Eichhorn, University of Mainz, Germany)is a fine screening model with a respected international reputation. The

model was carefully verified and validated while revising the code. The

test calculations are mainly oriented to the guidelines of the VDI-Code

3783/9, Environmental meteorology - Prognostic microscale wind field

models - Evaluation for flow around buildings and obstacles.

Prognostic wind fields solve the physical equations describing the tur-

bulent wind flow instead of matching physics with empirical assump-

tions as do the diagnostic models. This precision consumes a lot of

time! Most highly developed CFD-programs are too oversized for a

common planning job. They require a lot of input not available for an

environmental impact study, because they are made for research or

product development.

To find the best compromise between the quality of prognosis of a CFD

program and the time budget of a common planning job, MISKAM sets

strict boundaries for its application scope: The turbulences caused by

obstacles should be so dominant that thermal and terrain effects can

be ignored.

MISKAMdoes not regard terrain and is best used with neutral atmos-

pheric stability. Calculating in stable conditions is possible, but requires

much more calculation time. Unstable conditions are automatically set

to neutral stability. If your investigation area allows these restrictions,MISKAMis one of the best models you can use!

If you are not a meteorological expert, MISKAM's scope of application

should be restricted to inner city simulations like street canyons, park-

ing lots or situations where pollution sources are located close to the

recipients and where local changes of wind speed and turbulence have

to be regarded in a very high resolution. MISKAMis used for hot spots,

not for entire cities!

MISKAM allows simplifications: It is not necessary to calculate with

high resolved wind statistics, because the building structures cause

canalization effects. Also, it is not sensible to calculate with ann