if you are a foot from someone elses bumper at a stop sign, can you intake exhaust fumes from there car through the front of your car? my husband believes there is no way this happens.
Exhaust gases can enter the HVAC system from 20 feet away or while driving in traffic, the amount of exhaust will vary and won’t kill you.
If you see a stream of smoke emitting from an old diesel truck switch the system to “Recirculate” to keep the exhaust from entering your vehicle.
Not to bash your husband, but he must have a decreased sense of smell. Easily noticed when behind diesel trucks.