I think "respiratory protection" is a little over the top. A simple small fan blowing the fumes away is usually more than enough; if you want something better,

I think "respiratory protection" is a little over the top. A simple small fan blowing the fumes away is usually more than enough; if you want something better, a charcoal filter vacuum fan setup nearby works well, too. The rosin in solder is nothing more pine resin; it's identical to the resin used by violinists. In fact, it is easy and cheap to make your own "liquid rosin" for soldering (usually SMT drag soldering); you can make enough for a lifetime of use for what you would pay for a single MG Chemicals pen. Good to breath in? Nope. But hardly something that'll kill you, except in cases of chronic exposure (that is, if you breath it constantly every day for weeks on end - most hobbyists won't ever end up doing such). Now - acid core solder (not something you use on electronics, mind you - but generally for metalwork) is not something you want to breath in period. Whereas rosin core, while smelly, might just make you cough a bit (unless you are more sensitive than others), acid core will make you choke almost - and it burns your throat. Not only that, it can make your eyes sting (so - regardless of what solder you are using, eye protection goggles are definitely something to wear). Adequate ventilation for acid-core solder is a must; without such, you might actually find it worthwhile to wear a mask of some sort to prevent excess fume exposure.