opps compress air is a great producer of static , does an evan better job if it is dry ( which is what you need ) , earthing the nozzel will help but take great care.
Saw an demo on tv last night they had a fan with the input connected to the output ie closed loop , they then ( before connecting the pipe up )put some polystrene beads in to the pipe, in the pipe was a short lenght of metal pipe, when the fan was turned on 3/4" sparks could be seen jumping to earth !!!!!!