I have no idea myself. I've been looking around for hours; I even changed the water levels to the floor to top to see if it had a difference-nope-no difference. It's rather annoying since people and websites say there are when I haven't seen a single one for hours. Best give up buddy.
they contain much more gas than dust.
Condensation
nebula
Clouds are made up of tiny droplets of water that have condensed on dust particles in the atmosphere.
All clouds! Clouds are made of water and dust (and sometimes ice) and they all rain!
Castelia City, Desert Resort, Black City, or dust clouds
Caves sometimes have dust clouds. You may receive a Fire Stone by walking into one of these or by answering "Pansear" to a man in Castelia City.
tall grass, water, sand, and cement in the castelia sewers
Dust sticks to clouds, because of electricity.
Castelia City Sewers, Route 9 Hidden Grotto - Route 9
Since Eevee is a wild pokemon in Black and White 2 you can catch as many Eevee as you'd like. Eevee's can be found in the Castelia Park at the end of the Castelia Sewers.
clouds of dust and gas
Clouds of dust and gas.
they could be dust clouds.
You can find a Fire Stone by talking to man on the pier south of Castelia City's entrance. You can also find one Northwest of Psychic Gaven in the Desert Resort. Another method is by walking into dust clouds inside caves (though you won't always find a fire stone in these clouds).
no clouds are formed from dust particules and water
No.