Case Study 2: Dispersion Modelling

Paint fallout mystery solved.


The client's office was located in Dandenong South, a light industrial suburb of Melbourne. BELL Laboratories was sought out to determine the source of white paint fallout affecting the windows and paintwork of the client's staff vehicles.


The Solution.


The initial assumption was that the paint was a result of overspray. A number of businesses in the immediate area were identified as potential sources, the nearest being directly adjacent to the client's car park.


When the client expressed concern to the neighbours, they enlisted an independent environmental consultant to examine their spray painting process. The consultant found their systems and procedures were in order and that there was negligible risk of over-spray.


BELL Laboratories took paint samples from the client's vehicles and compared this with samples of the paint most commonly used by the neighbour. The samples were analysed using scanning electron microscopy (SEM) as well as energy dispersive spectroscopy (EDS).




Using both SEM and EDS methods, the paint fallout was identical to the sample of the neighbour's paint. However, the matching paint did not conclusively prove that the neighbour was the source of the paint. Other businesses in the area used the same spray paint and more work was needed.


Through analysis of the particle size range and density, as well as making some conservative estimates as to the likely maximum discharge height and velocity, we calculated the likely range of the paint aerosol. Using this approach, we could then draw conclusions as to the most likely source of the paint fallout.


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