Figure 4.1: Types of sources used by dispersion models
Return to the point in the document where this figure is located.
Text description of figure
Figure 4.1 shows several examples of emission sources. A point source is a chimney with key characteristics being stack diameter, height, temperature and exit velocity. An area source may be square or rectangular, or a polygon, or a combination of all of these. Circular sources may be approximated as a polygon. Square/rectangular sources can be characterised with an angle, off-setting the source from north. Other source types include line sources (such as drains or roads) and volume sources (commonly used to model fugitive emissions from buildings).
