Having a lot of problems with smoke in the CA Bay Area at the moment, I was wondering if the cabin air is passing through the cabin air filter while in recirculation mode - what's the best way to minimize cabin air pollution?
yes. Filters are positioned just before the blower motor, taking air from either the cabin or engine compartment (depending on the recirc setting). If it's hot outside, you don't want to leave your car sitting in recirc mode so the cabin can breathe. Best way to minimize cabin air pollution is to not drive or use electricity, highest contributors to poor air quality in populated areas.
Be careful when driving through areas with nearby forest fires. The cabin is not airtight so the smoke and smell will still enter the cabin through the hundreds of cavities in the body. But recirculate mode is best to keep the outside air out.