Introduction

Because the detection time or sampling time for odours is short, typically 3 to 5 seconds, or the time required to take one breath, conventional air dispersion models cannot be used to predict the concentrations of odorous materials. Conventional models usually predict the average concentration over periods of an hour or more.

Normal atmospheric turbulence is sufficient to cause local wind velocity to vary rapidly in both speed and direction and thereby to cause rapid fluctuations in the concentrations of an airborne pollutant at a fixed receptor position.

Conventional models 'average out' these short term fluctuations but for odour modelling it is necessary to determine whether short term fluctuations, which may include concentrations much higher than the 1 hour average values, are higher than odour detection thresholds.

It is difficult to predict the short-term peak concentration with any confidence but it is possible to devise a probability distribution function (pdf) of concentration and to determine what fraction of this pdf exceeds some predefined critical threshold.

What is Omonos ?

QUESTOR have developed Omonos, a user-friendly odour modelling program. Omonos has the following uses and features:

• a screening model for odour dispersion;
  


• predicts the probability of detection downwind of an odour source;
  


• runs under Windows 95/Windows NT;
  


• easy to use menus and toolbars;
  


• point, area and multiple source modelling;
  


• uses readily available input data;
  


• comprehensive data validation and helpful prompts;
  


• input files can be saved for reuse;
  


• graphical and textual output;
  


• output suitable for post-processing;
  


• comprehensive help system.

How does it work ?

Data are input into purpose built forms which handle validation and range checking.
The processing is carried out and the results are displayed in textual format which can be saved to a file for post processing.
Options are available to display the generated results as graphs on screen or as printed output, or to view the data in a contour representation or as a three dimensional surface.

Trial Version

QTL have developed a trial version of the Omonos program to let potential users evaluate the programat first hand. The trial version has full functionality apart from the following restrictions

• Release Height is always restricted to the value of 10 metres.
  


• Meteorological Data is always restricted with
  
  
  • A stability class value of 'B'
    
  
  
  • A 10 metre Wind Speed of 2.0 metres per second.

To download a trial version click here.

Consultancy

As with all our products QUESTOR Technologies provides a consultancy service for odour modelling.

As part of the service we work with the customer in obtaining the information specific to the site in question. Once this information is collated QUESTOR Technologies Ltd. runs our modelling software with the data collected.

The results produced by our software are analysed by ourselves and a detailed report is produced not only discussing these results, but also identifying any issues that may cause a potential nuisance and suggesting solutions to deal with them.

For further information on our environmental modelling consultancy service please contact:

John Stewart
The QUESTOR Centre
The Queen's University of Belfast
BT9 5AG
Phone: +44 (0)28 9097 4037
E-mail: j.r.stewart@qub.ac.uk

How to obtain the software

Omonos is available from QUESTOR Technologies Ltd. The list price is £275 plus VAT, but please check for any changes when ordering.

To order online simply click here, or for immediate dispatch by CD or email, please send your order, with payment in sterling to :

Product Sales,
QUESTOR Technologies Ltd,
David Keir Building,
Stranmillis Road,
Belfast,
Northern Ireland,
BT9 5AG