New tenant is asking to a vented booth in garage

[Jason Mauldin]

I have just started out as a landlord, and the tenant that I have is a wood worker.  He wants to build a booth in the attached garage so that he can varnish/paint furniture and vent the fumes outside.  

I've seen the plans and I don't think that I have an issue with the structure.  It seems to be a self standing structure that will be standing inside the garage.  He's going to use an existing window and door to vent the fumes. 

Are there any issues that I should be concerned about here?