Well, I guess I should have been more clear in my original post.
So of course there is a "recirculate" button on my Leaf but i noticed that when I turned it on to avoid a big blue cloud of smoke I was about to drive through, it didn't really work, that is, I still smelled fumes. In my Prius, and pretty much every car I've ever driven, recirculate meant close to zero outside air, at least according to my nose. In my Prius, the recirc button means I don't smell anything except myself. :lol: But today, in my Leaf, I was smelling some gasser's catalytic converter dumping sulfurous fumes going up a hill. No air conditioning, no heat, just fan and recirc. I'm going to do a test with some incense and report back what I find. then I'm going to find a charcoal filter of some sort and kludge it in next to the cabin filter if possible. Maybe my recirc door is just a little sticky? I can hear it making a noise like a soft click.
Anyhow, when i called and asked to speak to the Leaf certified technician, he told me that the Leaf has a common manifold in front of the windshield (under plastic cover) that directs air both into the cabin and into the battery compartment. Whatever. He then told me specifically that the Leaf does not have a 100% recirculate, that it just reduces outside air. Maybe he's full of it, but that's what my car is doing. I like my wife's prius with the pollen setting, but I always found recirc to be enough. And her car never fogs up - what is up with the leaf and fogging? I suspect this is why nissan decided to engineer in a little fresh air at all times.
FWIW, when I took off the inspection hatch over the high voltage disconnect, I could feel an immediate breeze blowing up into the car, but i'm not sure that is contiguous with the batteries themselves.