Ask the Expert Question-and-Answer Archive

by Ron Joseph

April, 2004

Paint Particulate Overspray

Q. Is there any data on Paint Particulate size from overspray? The CAM rule will apply to paint overspray particulate if it is PM10 or less in size. I tought the paint overspray from the paint gun was more like a wet "Globule" in characteristics?

A. The particulate size of overspray depends to a large extent on the distance between where the overspray settles and the spray gun. We have measured overspray that deposited up to 500yds. from the source and found that the particulate size was between 2 and 6 microns.

When we measured the particulate size of overspray closer to the source we found a few larger particles, but not the size of droplets.

We have also conducted tests in which we measured overspray only a few yards from the spray gun and here the particles were in droplets size and certainly greater than 10 microns.