Why do new things- like matresses- smell funny when you first open them?
The synthetic fibers in the mattress emit a faint gas, which accumulate to a smell-able level when enclosed in the protective bag for a while. Likewise new carpeting with synthetic fibers has a smell. A new office building was built here, and before it was occupied, the owners turned the heat up to 90 degrees or so for a couple of days to force the gases out from the synthetic fibers in the carpeting and furniture.
It’s called “outgassing” or “off-gassing”. Glues, sealants and chemical treatments will off-gas for a time. This is what causes “new car smell”, along with the sythetics.
I heard someplace that a new shower curtain will outgas half its weight (as plasticizers) over the course of its useful life - and have noticed that there is indeed a considerable weight change.
FTR, IIRC the compound which gives new carpet its distinctive smell is para-cyclohexylphenol.