From her story, she was already under very heavy strain before even moving in (full time program manager job which isn't something to sneeze at, and taking what sounds like a full time legal course at the same time), while moving into a new (and presumably expensive) apartment in what could be a new area. All this, presumably (based on references to '7 months' and 'September 2020 when I finally figured out what was going on', during a historic pandemic with massive, stressful shifts in work and school environments, availability of outlets/breakage in coping mechanisms, etc.
Throw in perhaps an unwillingness of a landlord to release someone from a lease (as the local high end single occupancy rental market has crashed > 40% during this time), nasty nasty air pollution for months (the fires definitely impacted me and my family on top of COVID related impacts during this time - literally months of unhealthy air, orange skies, my cousins house burned down in the santa cruz mountains and many areas I've loved to visit in the past burnt down - it was terrible for mental health), everyone in the medical community confused and scrambled - almost everyone has been going nuts, in many different ways, and the stress has often been incredible.
The whole south bay and peninsula is dotted with superfund sites, and she makes numerous references to public interest advocacy, so I'm sure she is aware of history the issues in the area and with legal training wouldn't lack the tools to dig.
If you move to a new place (very stressful) in the middle of all this, and get worse - it's also hard to look at 'non-negotiable' things like work or school as contributing, because, well, you handled them before and you can't stop now right?
If you run across something else that could be causing it, why not pursue it? Especially if they're a big corp or billionaire with deep pockets? Worst case they let you out of your overly expensive lease (now that the market collapsed) to get you off their back, best case you get a decent settlement to compensate you for the damage they caused (since you can't find anything else doing it).
One of the big challenges here in the bay area is everyone is always trigger happy legally for environmental issues, and most of this stuff is almost impossible to DISPROVE.
The science is really not great - we know some chemicals cause predictable things like cancers in certain situations - but there are a LOT of different chemicals, in a lot of different environments/states of weathering, in a lot of different types of exposure settings (residential with windows open a lot, residential with windows closed a lot, ground floor, top floor, near a vent, not near a vent, industrial, etc). And that isn't even counting all the different glues, adhesives, plastics, etc. in typical new construction. You can't run a good double blind study on this stuff (too many variables, ethical issues in many cases), animal models suck, chemical composition is sometimes not well documented or changed random over time, you name it.
Ideally we'd all live in untouched pastoral glades far from any industry, but that just isn't how the world works. People need to live near their jobs for efficiency reasons, jobs tend to be concentrated near businesses (or have been historically), businesses often make things, making things can be a messy and polluting business.