I was cutting some cane with a wet diamond saw and started thinking about the mist coming off of the blade and what it might contain. I collected some droplets, dried them down and looked at them in a scanning electron microscope. The particle sizes range from quite large to well below 1 micrometer. You definitely want to wear respiratory protection when wet cutting glass - you get a lot of mist produced and it's full of very tiny shards of glass. The image was taken at 25,000X magnification and the sale bar is 1 micrometer. You don't want to breath this mist and should clean up thoroughly afterward to keep the dust from becoming airborne.
Robert