Simultaneously several mills were sampled with a Portable Continuous Aerosol Monitor (PCAM) and vertical elutriators (VE). One set of VE filters was processed promptly, one set used for weighing and then forwarded to the laboratory, and the PCAM filters were processed after a delay.

Data from all three sets of filters are reasonably similar and serve to confirm the hypothesis that the airborne microbial and endotoxin levels are consistent and that reliable measurements can be obtained in the mill environment.

Regression equations link the microbial and endotoxin data to the dust levels as measured by the PCAM device.