I was messing around in processing, trying to see what neat effects I could create and I stumbled upon this almost quite accidentally.
Left click to create a dust cloud.
Top slider controls the size of the cloud.
Middle slider controls the minimum angle for new dust particles.
Bottom slider controls the maximum angle for new dust particles.
Note, if you download the code and change the variable "permanent" to true, the dust will stay. It is quite interesting as well.
To tweak this sketch, first download it.
Make your updates, then upload your tweak!