Do you have a shower curtain and a liner? Most shower curtain liners are made from PVC, polyvinyl chloride, which gives off harmful gases the second you hang it up in your bathroom. Instead, think like you're in a hotel and get a nylon shower curtain; it's waterproof and machine-washable and not made from PVC. The best part? When it looks dingy, just unhook it and wash away. ... Good as new!