Just wanted to update this thread, since the previous last word on the subject is no longer accurate. I thought the spike in particulates was just something I’d have to live with, but after some further investigation (described elsewhere) it turned out to be a leak and was mitigated with better tape (described elsewhere). The practical upshot is that PM2.5 levels are no longer useful as an indicator of whether the Glowforge is in use. They don’t actually spike at all, and there’s no detectable odor before the lid is opened. So, yay.