Adel

I have a Dutch Shepherd that that is a Search n Rescue and travels in my 2014 Silverado and his scent gets in the vents when fan is turned on. Your answer still doesn't explain how his smell stays in vent system. I just changed cabin filter and it was disgustingly dirty and filled with dog hair. How is this getting into the circulation system? Where does the air inside the truck get brought into the cabin filter?