I think the lead oxide vaporizes at melting point, which is a great reason not to use old oxidized solder. I have a Weller soldering air cleaner and only solder with it on and another fan in the room and the whole house A/C filtering fan turned to high (which is like 4000 cfm) with electro-static filters that remove smoke, viruses and cat pee smell just to avoid b b b br bbr brrr brain damage during soldering.....