2010 Saturn Vue sweet smell

There is a sweet smell coming out when the fan is on. Sometimes, only the defroster works even if I want ac and then there is a steam or smoke that comes out of the defroster. But typically, the car has a permanent sweet small that I hate coming from the vents. I took the car to two different mechanics, one of whom pressure tested the compressor (?) and said there is no leak. Both could smell the smell and asked if I spilled antifreeze or something, but I did not and even if someone did, it has not burnt off. Nobody can find a problem and the mechanics suggested that I wait for a while to see if anything happens, but the smell is hurting my lungs and eyes. What could it be?

Thanks.