'Clean' sand, without dust...lol.
Sorry, but a lot of sand that you buy, especially in bulk, has 'dirt' particles in it that can become airborne(ie:dust).
I spent a lot of time researching sand when doing concrete sculpture and the cleanest sand I found was Quikrete brand Fine Sand. It is washed and kiln dried, as dust free a sand as you'll find anywhere, and about $3-4 for a 50# bag. I now use it on my roost boards mixed with PDZ.
That said, I think eliminating dust in the coop is impossible. It has several sources: wood shaving bedding (I use the large flake as it's less dusty), chicken feed, dried feces, and I think the biggest source is feather sheathings. I used sand (the 'clean' sand mentioned above) for bedding the brooders in the house this spring and there was still alot of dust everywhere after 8 weeks of brooding.....most of which I believe came from the sheathing off all those feathers that young chicken grow out.
Sand works great in the brooder and on roost(poop) boards, but I think it's over rated as a coop or run bedding. Sure it's easy to sift poops out of and it drains well-which is great if your run is built on clay, but it doesn't necessarily dry things out like shavings do-essential inside the coop-especially if you live in a humid climate. And what do you do with it once it becomes sodden with feces and feed particulate? You can't clean it or compost it, you've got to dump it somewhere, which is what I ended up doing with the brooder bedding.
Face it, birds are dusty...where the term 'dirty bird' came from.