Basement maybe moldy

I currently live in a house with a basement. The basement is a real good shape but the maybe mold issue.
I have found some of the source and fixed it. but I still have a weird smell when I come in for laundry. What do you think it may be?
On top of that, when I close the lights and turn on a flash light I see a lot of little pieces in the air that I can't identify what are those?, the windows are closed so it can't be dust. maybe its the drop ceiling?
Ill be happy to hear any suggestions on what I should do..

Thanks