I've experienced this smell issue in both a Prius Prime and a Rav4 Prime, so I'm curious if perhaps it is a "feature" of Toyota's plug-in hybrids. For both cars, smell started after a few months and a few thousand miles on the odometer and has continued for a few months now without much change. New car smell was mostly gone by the time this new smell started. When we get in the car in the morning, there's a pretty noticeable and distinct smell kind of like strong plastic or windex. Usually seems to dissipate after a few minutes of running the A/C (bringing in outside air). Never caused a headache or anything, but just kind of an annoying smell to be hit by every time you get in the car. The smell is present regardless of whether the vehicle was recently charged or not. Both the Prius Prime and Rav4 Prime are parked in a garage, not exposed to sun or extreme heat. Anybody else notice anything similar re the smell?
Are you running the AC pretty much all the time? Humidity tends to accumulate inside the dash unit (similar to a glass of ice water on a hot day), collects pollen/dust, and can get moldy. To avoid this it's good practice to shut off AC a mile or so before your destination. Which is a pain I appreciate. There's also chemicals that can be shot in, through the AC water drain IIRC, to knock down the mold, if that's the problem.
I notice it in my 2021 Prime, but did not notice it in my 2018. Since it is only 3 months old I'm just assuming it's a new adhesive or plastic component offgassing. I practice shutting of the A/C compressor and running the fan on high for the last 5 minutes of driving as a habit, so I don't think it's that.
The A/c is on pretty much all the time. Smell is definitely not a moldy, mildewy smell though. It's a distinct plastic or chemical smell. Could that be caused by a/c moisture?
It has a distinct urea/formaldehyde note to the smell. That's why I suspect it's some of the plastics/foam in the car.