Hi There,
here is the tutorial I followed to create the clouds in my scene:
http://3dtreat.com/pages/tutorials/CloudTutorialPage/index.html
I just rendered the 3d cloud to create flat textures.

I also modifed the settings to create the dust cloud. Details of how to animate the particles and add forces to them can be found here:

http://www.digitaltutors.com/digital_tutors/video.php?v=1