Appendix 5 - Air quality assessment report

4             Air Dispersion Modelling
4.1           Overview
Air dispersion modelling has been undertaken to assess the potential for air quality impacts on the
nearest receptors. The following sections present the modelling methodology, input data and
predicted results.



4.2           Modelling Methodology
4.2.1         Introduction
Atmospheric dispersion modelling involves the mathematical simulation of the dispersion of air
contaminants in the environment. The modelling utilises a range of information to estimate the
dispersion of pollutants released from a source including:

⚫ meteorological data for surface and upper air winds, temperature and pressure profiles, as well
     as humidity, rainfall, cloud cover and ceiling height information;

⚫ emissions parameters including source location and height, source dimensions and physical
     parameters (e.g. exit velocity and temperature) along with pollutant mass emission rates;

⚫ terrain elevations and land use both at the source and throughout the surrounding region;
⚫ the location, height and width of any obstructions (such as buildings or other structures) that
     could significantly impact on the dispersion of the plume; and

⚫ sensitive receptor locations and heights.
For the purpose of the assessment, meteorological modelling has been undertaken using TAPM (The
Air Pollution Model) and CALMET to predict localised meteorological conditions. The meteorological
data derived from these models has been used as an input for the CALPUFF dispersion modelling.

4.2.2         TAPM
A site specific meteorological data set has been determined using the prognostic model TAPM (The
Air Pollution Model). Prognostic models, such as TAPM, permit the development of localised
meteorological data sets, based on synoptic weather conditions. The model predicts the regional
flows important to dispersion, such as sea breezes and terrain induced flows, against a background
of larger-scale meteorology provided by synoptic analyses. The output of this model provides a
meteorological data set suitable for introduction into a diagnostic meteorological model, such as
CALMET. Where good quality prognostic data is available for a site, this methodology is the
recommended approach for the modelling of contaminant concentrations using CALMET 1. It is noted

1   TRC Environmental Corporation (March 2011) 'Generic Guidance and Optimum Model Settings for the CALPUFF Modelling
    System for Inclusion into the ‘Approved Methods for the Modelling and Assessments of Air Pollutants in NSW, Australia’
    prepared on behalf of the NSW Office of Environment and Heritage.



                                                                                                                                       Page 16 of 35
                                                                 Belo Developments- Air Quality Assessment - Proposed Service Station, Noosaville
                                                                                             /Network/Projects/4694.2/Reporting/4694.2-AirReport02.odt