This is in relation to his crossbow with the damaging bolt. If you have information on the micro smoke too, that would also be helpful, but I'm mainly looking for the damaging one.
Okay I went and did some research and unlocked Capitao.
Just as a first, here is a video showing the burn radius of the fire bolt.
The smoke lasts for about 10 seconds. The smoke doesn't prevent visibility as much as a smoke grenade, while you're outside of it, but when you enter its radius it's a 0 visibility.