Experimental grain dust atmospheres generated by wet and dry aerosolization techniques.

Properties of grain dust aerosols generated using wet and dry techniques were studied. Relative to the dry aerosol generation, the wet generation technique yielded a smaller particle size distribution (MMAED of 1.5 microns vs. 15.5 microns) but also reduced the viability of microorganisms. Analysis of dust mass and endotoxin activity on cascade impactor stages demonstrated equivalent partitioning of the airborne endotoxin with the dust mass for aerosols produced by either generation method. Comparison of laboratory-generated atmospheres to field sampling indicated a greater proportion of respirable microorganisms in soybean handling facilities than were generated using the dry aerosol system. Limitations of both aerosol generation systems were found that may affect the validity of inhalation toxicology studies in which these bioaerosols are artificially created.