"People would wear N95s when working with a shit-ton of visible particulates, but otherwise are constantly leaving their lungs unprotected." Correct. And I sa

"People would wear N95s when working with a shit-ton of visible particulates, but otherwise are constantly leaving their lungs unprotected." Correct. And I say that as both a solderer and woodworker! In fact, woodworking often scares me more than soldering (as with wood there are more variables involved). Some particulates from wood are down outright dangerous—in fact, many different types of woods can either cause cancer or serious lung irritation. The reasons are that (a) the wood itself can have microscopic hook-like structures that embed themselves into one's lungs and they're sufficiently resilient not to be dissolved by body enzymes etc. before they do damage, and (b) some woods contain toxic chemicals, terpenes etc. which plants usually manufacture to deter or destroy pests. Terpenes are a large class of organic chemicals with a wide range of properties, some are relatively innocuous to humans and others can be harmful, in fact, some terpenes are considered a cancer risk. The flux rosin used in solder consists mostly of terpenes, so if you're one of those who worries about using Pb/Sn solder then you've more than just the lead to worry about. There's an image of natural resins here on this Wiki terpene page: https://en.wikipedia.org/wiki/Terpene https://en.wikipedia.org/wiki/Terpene Here's a few references about wood and wood dust toxicity: The Wood Database: https://www.wood-database.com/wood-articles/wood-allergies-and-toxicity/ https://www.wood-database.com/wood-articles/wood-allergies-a... and Wood Dust Exposure and Lung Cancer Risk: https://www.verywellhealth.com/wood-dust-and-lung-cancer-whos-at-risk-3971878 https://www.verywellhealth.com/wood-dust-and-lung-cancer-who.... There are many others. To protect yourself always use an N95 (aka P2) mask when sanding, sawing or doing fine routing—any work that produces fine wood dust/particulates. What about aerosol terpenes produced in the cuttings you ask? I'd suggest that if you are wearing a mask then the volatiles that actually get through the mask will unlikely cause you any problems (the practical consensus is that it's the fine particulates that lodge in your lungs that actually cause most of the danger). Of course, the same goes for cement dust, other powdered minerals including even talc and of course asbestos. Over the years, I've done a great deal of soldering and it's mainly been with Pb/Sn solder. Normally, for casual work 60/40 or eutectic are my choice as lead-free requires more care/setup and closer temperature tolerances, and there is a higher risk of damaging components with excessive heat. For PWA [circuit boards] production runs etc. it's a no-brainer, you should always use lead-free solders. These days it's dead easy to use lead-free on PWA production runs as the processes can now be held to such close tolerances. When soldering, braising or welding always remember to apply the cleanliness is next to godliness rule. Always use masks, keep the area well ventilated, and always wash your hands especially so after handling Pb (lead) and finally vacuum up all the metal dust and other crap with a vacuum cleaner that has a HEP filter.