Plumbing re-routed through attic
I Build homes in Arizona and use 100% PEX in construction. To be honest with you I have never noticed any odor at all from the pipe so my guess is the odor must dissipate. I lived in a house that was PEX as well and did not notice a smell. I imagine it could be different if you are already living in an enclosed home when the PEX is installed, but there are no solvents or glues used so I'm still at a loss for where the smell could be coming. I hope this helps. You might reach out to UPONOR based in Minneapolis. I think they are the manufacturers.