Soldering without adequate ventilation is a big no-no. Every roll of solder includes such warnings, but some hobbyists and pros still solder in closed-off spaces with little to no air crossflow. To avoid breathing in nasty and toxic solder fumes, you need to push or pull the fumes away from your face, and to do this you can open a window, set up a desk or floor fan, purchase a fume extractor, or you can build your own extractor/ventilator.
One of the more elegant DIY designs we have found, shown above, uses an array of four simple computer fans to pull fumes away from your body and face. The design, by oomlout, does not filter solder and flux fumes, it simply pulls them away. Still, it looks to be a very effective means by which to clear fumes away from your personal workspace.
The plans call for a laser-cut grill and two legs to form an upright stand, but you should also be able to make do with simple hand and power tools. 80mm computer case fans are easy to find, and should be quite inexpensive as well. The plans do not discuss power requirements, but you will generally need a 12-volt power source and a simple on/off switch.
There doesn’t look to be any reason why you could not attach a carbon filter at the front or rear of the fan to absorb solder and flux fumes rather than just moving them around.
Design and Laser Files, via oomlout
If you’d rather just buy a fume extractor that’s ready to go, there are a number of makes and models available via Amazon. We’ve heard good things about Weller’s simple desktop extractor and are happy with the Edsyn we use in our shop.