I have brown mucus coming from my nose, not a lot and it's not blood, i work in semi trucks where it's dusty, could it be dust? i have a cough also

Likely: If this has persistent for a while then it is most likely just dust. The way to figure this out is try avoidance for several days and see if it clears up. Daily use of a nasal rinsing system may help relieve some of the irritation that you are experiencing.

Multiple causes: dirt, dust, irritation with old blood in the sinuses, allergies, low grade infection: get checked and examined.