Maybe it's just lead fumes from soldering?
Also, home chemistry is not a bad thing. I'd rather someone go through the trouble and effort to build a fumehood and practice hobby chemistry at home than do it unsafely. But generations of scientists grew up with chemistry sets that they got for Christmas or birthday, and grew up to be some of the greatest minds we have in science. We would not have nearly so many great scientists and such great technology if not home chemistry and science.
These days the "nanny state" is working so hard to prevent people from doing anything fun or interesting in their own homes because it's "dangerous, and only for professionals". Laser hobbyists should know all about how this isn't what we want or need. Without these hobbies being accessible and getting kids interested in science, we won't have the scientists that we'll need moving forward. Where do people think these experts came from? They started in their basements and backyards and developed a life-long interest. A lot of the first people in Nasa got into rockets in their backyards (good movie: October Sky), a lot of chemists got into chemistry through home chemistry sets.
Especially with the internet now, it's so easy to go out, get good information, and be a responsible hobbyist.
Be safe, be responsible, but home chemistry can be a great thing. And if someone is serious enough to be wanting to build a fumehood for themselves and their own safety, sounds like they're the kind of responsible person who can handle doing home science.
Sorry, that's my rant for the day. Science is a good thing, even in your bedroom, especially if you're willing to seek knowledge and do things responsibly, the RIGHT way.