Urban Particulate Matter dust curves usually have a node measuring 5 to 10 microns. A study by Dr. Flocchini at UC Davis also shows the EPA's emission factors to be higher than the actual emissions. The conclusion would be that dairies are primarily a source of large particulate matter, that is not a health concern compared to urban sources of particulate matter. It is a choice of dust versus odor. In California, feedlots must have sprinklers.
Wet manure produces stronger odors than dry manure.
I have a patent on an anaerobic digester that processes biomass gas. The anaerobic digester has met with low market success because it does not compete with the price of Natural Gas as a source of electricity for the operator. However, it should still be considered as a method for reducing odors from dairy operations that use holding ponds. Schwang in North Texas was able to reduce odors at dairy operations by pumping the liquid from holding ponds back into the soil. However, in my opinion, there are legitimate concerns about pathogens leaching through the soil into the water table.