Like probably everyone else here I do a ton of soldering. When I setup my current workshop I built a fume extractor that actually goes in a window near my bench. Basically just a length of dryer duct with a high flow fan that vents directly outside. This is all an well, but kind of annoying to setup every time. I did this because, at the time, I felt that venting directly outside was clearly going to be better than an activated charcoal filter.
So, was I wrong? Can a simple filter be just as good as exterior venting? Or at least close enough? Has anyone ever found any hard data on how much lead and other toxins a charcoal filter will remove? Would adding a HEPA filter in the mix help?