Orlan,

There are many methods to assess dustiness. This has been an area of interest for me for years, and I have been thinking of assembling a collection of various methods as a contribution to the industry.

The basic decision is to define what you mean by dustiness (what size or behavior constitutes dust?). The method will follow from this. For most people, and probably for your application, "dust" means the very fine particles that will hang in the air for long periods of time, not larger particles that soon fall. This is related to size and electical characteristics.

I would suggest an optical method rather than a gravimetric method for this type of very fine material. We use a custom-built unit that measures light transmittance through the dusty air, but I have heard that there is a commercial one on the market now. I do not have the reference currently.

I would be glad to elaborate more, but do not have time until next week due to urgent matters at present.

Vic Granquist

Nufarm Specialty Products, Inc. ■