I'm pretty sure the "smoke" is just water vapor. It's coming from the medical/pharmaceutical device manufacturing facility that's right behind Diamond Jamboree. The facility is owned/run by B. Braun Medical, and it's been there for years (even before Diamond Jamboree was built). As far back as I could remember, the facility has always been ejecting the vapor. If you're concerned, you should call the facility to ask what exactly the is the "smoke" made of. Personally, I don't really think it's an issue.