I wonder, if you don't like the effects of dusting the top of the dough with flour, if you might not get better results with oil.
Pastry dough tends to be rich to begin with so the added oil might not be obvious, and a little brush shouldn't hurt the dough, and can be controlled fairly easily - nothing in the air or running off the sides. You might apply a thin layer to the top of your dough, or to the knife itself (either as a brush every now and then, or something like the mist idea). You probably won't need much extra (for cost purposes), and you will also avoid the dough drying too much around the edges. I think it might work.
Otherwise, I second Muriel Katz's answer - you should check the temperature. Cooler dough (and a cooler blade) will probably cut more cleanly than warm and soft dough. Depending on your process, you might get some improvement if you are able to change the temperature of the room, the dough, or the knife - whatever suits your setup.
Using water - may or may not be a good idea. It will depend on how wet your dough is, the temperature, and host of other factors. I have had dough which could be separated and moved quite cleanly, using water instead of flour to prevent sticking - I have also had dough all but melt because it became too wet with puddled water. With misters to keep adding moisture, it makes me feel like you would sometimes get the latter result, once the layer of water has a chance to soak into the dough.
Also, I have no idea how compressed air would or would not work. It depends on what you want to achieve with it, I guess - it might briefly chill the blade or the dough to cut more cleanly, but I don't think it would clean the blade or form a layer against sticking. Maybe someone with more experience with compressed air can answer.