AFRL 03 TEST DUST IS MADE FROM 34% QUARTZ, 30% GYPSUM, 17% APLITE, 14% DOLOMITE AND 5% SALT.   AFRL 03 TEST DUST Particle Size Distribution (particle size is measured with a Microtrac S3500 analyzer) Pecentile Size(µm) 10 3.5 +/- 1.0 50 15.5 +/- 1.0 90 46.5 +/- 4.5 10 pounds