Air quality sensors probably won’t get you the information you want. The ones available will be able to detect small particulate, indoor gases like CO or CO2 which wouldn’t be the issue, or very vague broad swaths of compounds lumped together which again are only relevant at high concentrations achieved only in enclosed spaces.

If there is something going on the most likely culprit is something specific with toxic effects at quite low doses that just wouldn’t be detectable without very specialized equipment (5,6,7? Digit costs)