See above please
My car has 40000 miles.
My car has an automatic transmission.
This is a common issue when the cabin filter needs to be replaced. Your vehicle has an air filter that filters the outside air as it is circulated into the vehicle when using the heater or air conditioning system. As the outside air is passes through your car's system, it collects dirt, dust and other impurities much like your engine air filter does for the engine. When this gets dirty and collects dirt and debris from outside, this will tend to emit an odor like smell when the vents are opened as you have experienced. This is easily remedied by having this filter replaced with a fresh clean filter. I would recommend having an expert from YourMechanic come to your location to replace your cabin air filter.
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