Overview

Many planning processes require calcula-

tions for noise emissions and air pollution

dispersion. It is welcome news to hear

SoundPLAN has a uniform software inter-

face for both types of calculations so users

can work efficiently in both areas of exper-

tise.

SoundPLAN air pollution modules build a

comfortable bridge between science and en-

gineering:

Embedding scientific calculation kernels in

the user friendly interface of SoundPLAN

and adding specific tools for data control, da-

ta conversion and result presentation,

SoundPLAN creates an environment for

high efficient air pollution dispersion calcula-

tion, benefitted from over 25 years of noise

programming experience.

Calculation Models - Overview

2

Base Module Air Pollution

The Base Module Air Pollution

generates the environment where

all modules are embedded. Besides

the basic modules for data input,

calculation and result presentation

it contains special air pollution li-

brary tools which are designed to

make your work easy, efficient and

transparent. If you own already a

SoundPLAN license, no matter if it

is for acoustics or air pollution, the

base module is discounted by 50%.

MISKAM advanced – wind field and dispersion model

MISKAM is a prognostic wind field

model completed by an Eulerian

dispersion model. The MISKAM

kernel is mainly designed for highly

resolved street canyons (1-2 m) in

dense built areas. For coarser grid

spaces we recommend GRAL.

Those two models complete each

other in a most sensible way.

The established, highly recom-

mended and steadily validated

model MISKAM is ideal for detailed

studies, when air movements

around buildings suppress stronger

thermal effects (neutral atmos-

phere). Stable atmosphere can also

be calculated for single case stud-

ies (worst case studies).

In opposite to former versions of

the SoundPLAN MISKAM interface

MISKAM advanced provides addi-

tionally underflow of buildings,

flow-through of vegetation and a

64 bit version.

The former, slim version is still

maintained for customers owning

a continuous maintenance con-

tract, but only the complete ver-

sion MISKAM advanced is further

sold.

GRAL system – GRAL dispersion model

GRAL system contains of two pro-

grams. GRAL is a highly recom-

mended Austrian Lagrange particle

dispersion model. To adjust the

GRAL wind field to the terrain and

landuse effects, the program

GRAMM is used as meteorological

preprocessor.

GRAL calculates as well for meso-

scale as for microscale tasks. It is

suitable to include traffic sources

in street canyons.

The microscale calculations are not

as precise as those of MISKAM, but

as soon as the borders of MISKAM

are exceeded, e.g. by project size,

atmospheric conditions, terrain

shape, grid resolution and calcula-

tion time, GRAL is the model to

continue on a larger scale.

GRAL uses optionally a diagnostic

wind field approach or a mixed ap-

proach, which can take explicitly

buildings into account by calculat-

ing a prognostic wind field around

the buildings.

Also tunnel portals can be mo-

deled.

GRAL system will be released in

April 2014.

Calculation Models - Overview

3

GRAL system – GRAMM wind fields

GRAMM was developed to calcu-

late wind fields in the complex to-

pography of the Austrian Alps. It is

capable to regard strongly undu-

lated terrain and differentiated

land use.

As prognostic model it can handle

much more details of topography

and land use than the TALDIA

model delivered with Austal2000.

It also regards cold air flows in a

generalized approach.

However – it is a mesoscale model.

It should not resolve topography in

a too fine resolution because it

won't handle stalls. Obstacles

should be modeled by buildings.

GRAL system will be released in

April 2014.

GaussTA Luft'86 – simple plume model

GaussTA Luft'86 is an "old fashioned"

plume model for quick estimations:

The formulas of the former Ger-

man standard "TA Luft '86" are

suitable for approximate calcula-

tions, e.g. to estimate background

concentrations or to make worst

case studies, whenever free flow

conditions can be assumed around

emission sources.

Even though it is the simplest of

our models, it requires good back-

ground knowledge to understand,

for which situations such a statisti-

cal approach can be used and how

the results must be assessed.

AUSTAL2000 interface – wind field and dispersion model

AUSTAL2000, a Lagrange Particle

dispersion model, replaced the

Gauss module as German national

standard for industry approval in

2002. It is the public domain refer-

ence model of the current German

directive "TA Luft 02".

As it is freeware under GNU li-

cense, it is distributed with the

SoundPLAN interface, completed

by the diagnostic wind field model

TALDIA, which can be used for

smoothly undulated topography,

and VDISP, which calculates the

thermal upstream effects of hot

sources and cooling towers.

The original model input and out-

put of all three programs is ASCII

based and restrictively designed to

fulfill the demands of German di-

rectives.

SoundPLAN adds a user friendly in-

terface because an interface is ur-

gently needed for an efficient use.

Austal2000 mainly supports di-

rective 2008/50/EC. If national

standards require different thresh-

olds or aggregations (e.g. 25 daily

means instead of 35 daily means

for PM10), these are soon availa-

ble: A more flexible kernel version

was just released in March 2014.

The SoundPLAN interface will soon

be adjusted until summer 2014.

Even in the new version, Austal-

2000 doesn't allow multithread-

ing/distributed computing.

Calculation Models - Comparison

4

What can you expect from a model?

What does the model expect from you?

Topography

Topography has a big influence on the wind flow. On

one hand it is an obstacle which deflects the wind di-

rection. On the other hand slope inclinations and slope

orientation have a big influence on global radiation

and the energy balance of a surface, so that thermal

flows can be induced.

There are two relevant questions which have im-

portance for the model selection:

Is the wind flow within the investigation area ho-

mogenous or is it disturbed by topographic obsta-

cles inside or outside the area? Homogeneous flow

can mostly be calculated without terrain model.

Is the wind flow within the model area represented

by the meteorological measurement point - in

combination with the model topography?

Is the measurement height above ground appropri-

ate for the model? Chimneys reaching high above a

valley can't be calculated with meteorology meas-

ured on the valley ground.

It is not enough to have a calculation model that can

handle topography. Topography requires high quality

input data for meteorology.

Modeling the influence of topography is the most diffi-

cult work. The first step to solve this problem is to

know, when topography can be ignored.

If the source is high above the ground and the ter-

rain is only smoothly undulated, it can be sensible

to model with flat terrain.

If the influence of topography is homogenous with-

in the calculation area and already well represented

by the meteorological measurement, it can also be

sensible to model flat terrain, even on ground of a

deep valley.

Why should you ignore topography, when it is already

nicely modeled and available from the noise part of

your SoundPLAN project?

Modeling topography is indeed easy within

SoundPLAN, but modeling the air flow above the ter-

rain is something different:

The size of the calculation area must be big enough to

regard all the terrain which is reflected in the meteoro-

logical measurement. In complex terrain it is often

necessary to make local measurement.

How do the models treat topography?

MISKAM calculates without topography. It can be

used for flat or homogeneously inclined areas. As

MISKAM calculation areas are rather small, this is

often no problem. In some cases it can be sensible

to model terrain edges carefully (!) simplified by

buildings. However, regard that MISKAM displays

the result layers parallel to the flat model ground.

Calculation Models - Comparison

5

GRAL system can calculate flat or include mesoscale

wind fields calculated with GRAMM - as well for

smoothly undulated as for complex terrain. The use

of GRAMM in complex terrain requires really mete-

orological expert's knowledge, especially to find

sensible measurement locations for meteorology.

We will try to offer trainings and model setup con-

sulting together with the program authors, but set-

ting up difficult projects will not be part of the hot-

line support.

Austal2000 calculates with flat or smoothly undu-

lated terrain up to 20% incline. The result display

layers follow parallel to the terrain heights.

Regard of topography should be handled with care.

Even for smoothly undulated terrain the calculation

area must often be much bigger than the investiga-

tion area. Thermal induced wind flow is not regard-

ed in the model; this might be a problem if e.g. a

cold air flow crosses a part of the investigation area.

GaussTA Luft'86 ignores topography and should

therefore mainly be used for chimneys.

Landuse and buildings

Landuse determines the vertical exchange of air close

to the ground. Obstacles like trees, bushes and build-

ings cause turbulence. This causes on one hand a re-

duction of the mean wind speed or brings chimney pol-

lutants quicker down to the ground; on the other hand

it helps to bring pollutants from the ground to higher

atmosphere layers.

The closer the sources and the annoyed receivers are

located to each other, the more an individual resolu-

tion of those obstacles is sensible.

MISKAM advanced, as microscale model, offers the

most detailed resolution of obstacles. It regards

buildings, underflow of buildings and, if necessary,

even detailed flow through vegetation with differ-

ent layers of leaf density. In the inflow and outflow

area of the model geometries, those obstacles can

be generalized as "roughness areas". Those are are-

as with different roughness parameters which in-

fluence turbulence and wind speed.

GRAL resolves in its microscale mode buildings in

diagnostic or prognostic mode. Land use areas can

be applied by precalculating mesoscale wind fields

with GRAMM. GRAMM derives from landuse areas

roughness length and further parameters like albe-

do etc., which influence the energy balance and lo-

cal wind flow. Defining landuse by the CORINE

landuse classes, GRAL is the most universal model.

Austal2000 with its wind field model TALdia re-

quires a generalized roughness definition for the

whole area, what can be a problem especially for

ground near sources. Buildings can be regarded in a

fine resolution to model the turbulence influence

for low chimneys. The wind flow between complex

building structures is not capable to calculate sensi-

ble results for street canyons. All emission sources

should therefore have a more or less free wind in-

flow. Austal2000 is a reference model for sources

above 1,2 times the average obstacle height with

buildings modeled or 1,7 times above the average

obstacle height if buildings are only regarded by

roughness length.

Calculation Models - Comparison

6

Gauss doesn't resolve any landuse parameter. It

just requires free flow conditions around the

source, what is best ensured with high chimneys.

Meteorology

The models use meteorological data in a different way.

MISKAM reads meteo data like wind speed and

wind direction as wind inflow into the area. There-

fore the investigation area must be surrounded by a

400-500 m belt of (generalized) buildings which ad-

justs the wind speed and wind directions to the

building structure before it reaches the investiga-

tion area.

GRAL and GRAMM also read the meteo data as in-

flow data. GRAMM modifies the inflow to repro-

duce the flow at the anemometer station with sev-

eral approaches. The model must hold the physics

within the whole model area consistent. As the to-

pography is clipped by the rectangular calculation

area, influences from outside can be less homoge-

neous than modeled. It depends on both the quality

of measurement and modeling, where in the model

area the wind field can be called representative.

Austal2000 calculates a simple diagnostic standard

wind field and adjusts it to the measured wind

speed at the anemometer station. If the anemome-

ter is well located, this works fine for smoothly un-

dulated terrain. If the weather statistics are meas-

ured outside the area and transposed to an imagi-

nary station within the area, the quality of modeling

decreases commonly with the increase of slope in-

clination.

Gauss takes the flow defined in the meteo statistics

as flow at the source. The wind speed is corrected

by logarithmic wind speed profiles.

Emissions

Worldwide there are lots of different standards to de-

rive emissions, each using completely different source

parameters. Therefore SoundPLAN doesn't calculate

emissions. However, if you assign clear identifiers as

source name to your source objects, you can easily im-

port the emissions from almost free definable, column

oriented ASCII tables.

Most emission models for traffic emission are made

for coarse inventories and they don't have the resolu-

tion to feed a microscale model like MISKAM. For Eu-

rope we intend to connect the Austrian traffic emission

model NEMO to the road sources. It uses the same da-

ta base as the standard HBEFA/MICET, but already

sensibly aggregated for whole roads instead of single

cars. The programming of NEMO and much of the

measurement for HBEFA/MICET is made at the tech-

nical University of Graz. Therefore the NEMO data

base is always a bit quicker updated than

HBEFA/MICET. Maybe it can once become a worldwide

solution.

Calculation results and limit values

Calculations as well as measurement represent stable

values for annual mean concentrations. Extreme val-

ues instead occur mostly unforeseeable or even unex-

plainable in measurement, therefore it is not very

probable to believe, that they are included well dosed

in a model calculation. Therefore older regulations

looked on annual means, median, P 95 and perhaps P

98. In Europe instead, the critical load for hourly NO2

concentrations equals in measurement data the per-

centile P 99,8 (18 h).

We offer free definable percentile results (except for

Austal2000), because they are sensible to compare

planning options. For limit value comparison instead

we strictly recommend, to derive the extreme values

(or the probability to exceed extreme limits) from cal-

culated annual mean values, as it is mostly done in

Germany. Maybe the implemented German functions

must be modified according to your national statistics.

If there are any equations available, they can simply be

applied to the result maps by using the grid operations

of SoundPLAN's Graphics module.

Training

7

The purchase process often begins with using a demo

version to get an understanding of modeling tech-

niques before making a decision to purchase. For air

pollution propagation, there are many details to learn

about the different models besides learning how to

use the software. Especially if air pollution prognosis

is a new field of study, we feel the most efficient way

to begin is to attend a training session.

Although air pollution prognosis is a complex matter,

it doesn’t take long to learn how to recognize and

avoid problems throughout process. The model de-

velopers have done their work correctly, so you don’t

have to worry about the mathematics and the physics.

We focus your attention on weather and pollution ef-

fects, much of which you already know, and then

show you how these effects are parameterized as

model input for the different model approaches.

SoundPLAN air training shows the maximum reliabil-

ity expected in projects and the minimum data quality

required. It shows how the interaction between input

data and the calculation model determine model se-

lection. Above all, it shows how to maximize your time

and efforts for efficient, accurate air pollution progno-

sis.

Contents:

Wind in Nature

appearance and importance of

large scale and local wind sys-

tems

Modeling Wind

measurement and parameteri-

zation of wind characteristics

plumes and wind fields

Model Approaches

statistical approach

diagnostic approach

prognostic approach

Source Modeling

general approaches

modeling in SoundPLAN

HBEFA road emissions

Calculation Control

optimizing parameter settings

control by files & graphics

Result Display

wind fields

concentrations

post processing operations

The training projects and presentation slides are available on DVD. Three training days are required to fully cover

the topics for experienced SoundPLAN noise users. Four days should be planned for newcomers. Attendance from

first to last session is mandatory. If you want to discuss project data, send them to hotline.air@soundplan.de be-

forehand with a description of the situation. We’ll look for ways to assist you with your particular projects, but

special preparations will increase the price. Prices will be calculated individually on request.

Modular architecture

SoundPLAN offers modular architecture in a double sense:

1. Working with SoundPLAN the work flow is split into several program modules to avoid an overload of buttons

within one interface and to assist an efficient organization of big projects with several model variants and cal-

culation tasks.

2. The calculation models are offered as separate license modules in the price list, because air pollution tasks can

be very different and require well selected model approaches. They spread from a "simple" Gauss model up to

complex prognostic models.

However, even if you can decide to buy as well simple as complex models, this is often misunderstood as a ques-

tion of comfort or background knowledge. Far from it! A wrong model selection can be more expensive than the

most expensive model!

The model selection depends strongly on the model area, the results requested by the directives and the available

input data. Therefore the modules can't simply replace each other.

To avoid damages we offer training sessions, designed to transport the needed background knowledge to con-

sultants who started with acoustics and want to enter the air pollution field.

As special offer to animate your training motivation we discount up to 20% of the module price from the train-

ing price, if you order a training within 3 months before or after purchasing the program.