Do you guys drive around with this thing turned on?

The air circulation button on my car is turned on almost constantly. I do it to keep out outside dust and pollution. Sometimes I turn it off to let some "fresh" air in.

Sometimes I worry that I am breathing in stale air. ChatGPT tells me there is enough oxygen for a single person to stay awake and alive for 6 hours. A full car will turn fatal in 3hrs.

What is your take?