I am having this same problem with my 2005 Dakota QC, and I agree it is cheap brake pads. Stop good-wear out quick (i.e. made to sell, not to use). I had this problem on my Jeep, and replaced the pads with ceramic pads. No more brake dust, and no annoying squeal like some of the metallics.

 

Change your brake pads to the ceramic type. They are pricier, but I changed to them on one of my previous trucks and the dust went away. It all depends on the type of pad you use...and while you're at it, change your rotors.