Classroom Triggers Asthma

I’m a teacher with very mild, easily controlled asthma/allergies outside of school, but I’m having a really difficult time with my classroom. I feel completely fine when I’m away from school, but when I’m in my classroom all day I develop chest tightness/irritation, coughing, and some rib/upper-back soreness. It clears up completely when I leave for weekends/vacation.

I’ve talked to multiple doctors and did a full allergy panel that came back negative for everything except cats, but their policy is they can't say the room is what's causing it and just advise I get out. I take Claritin and Breyna 4x a day so I'm maxed out on asthma meds and still have symptoms. Workers comp dismissed it as a preexisting condition even though my symptoms are documented as having been well managed before this job and I have 40 pages of documented symptoms from last year. Admin has been sympathetic and did move me to another room with better ventilation, but I’m having similar issues there and multiple other rooms across the entire campus. I've also done trainings at other schools in the district and noticed similar chemical smells that affected me there so moving schools within the district likely won't be a solution. I survived last year wearing an N95 in my previous room, but it isn't as effective in the new one, and a carbon-filter mask only helps somewhat so far. I have 4 HEPA air filters running in the room constantly and am working on adding charcoal filters to all of them since this seems to be a VOC issue. I subbed for years at multiple other districts and never had this problem at any school until joining this district.

Other teachers have complained about facilities and my students have complained about indoor air quality at the school to me, but I seem to be the only one who reacts this badly and my air-quality monitor generally shows normal readings so I'm afraid if I pursued it further any inspections would just be dismissed as unremarkable. There are regular cleaner smells, something like xerox, occasional weed that filters in from the bathrooms, paint smells in the indoor hall, and a lot of rooms with air fresheners, so I wouldn't say it's perfectly fine but I've been stressing myself out doing tons of HVAC and IAQ research trying to prove it and find a solution myself because I really like this job otherwise and teach a subject not currently in demand so switching districts here will be difficult. Quiting or FMLA are not an option because I have no financial support to fall back on. The union has also been sympathetic as well but I'm afraid to push things further. My next step is going to be to reach out to the head custodian and see if we can pause all cleaners for a month or so to see if that makes a difference, but my gut tells me it's HVAC related somehow, so I don't even know what they could realistically do about that.

I'd just really love to connect with someone who has gone through something similar and won't start with 'are you sure you're not imagining it?' Are you out there? Did you ever figure out what was triggering it, or get your school/district to actually investigate? I'd love to find a solution to preserve this job, but I'm running out of steam coming home sick everyday so I think the writing may be on the wall, unfortunately.