It IS the same category when it makes you suffer. Be it sneezes, running nose, coughing, swelling throat, burning eyes, sometimes itching skin, feeling unwell in general after being in contact with or near that stuff.
Maybe our bodies have different tresholds for exposure to that stuff, and after oversaturating them for some time, there is no buffer available anymore?
Maybe our bodies have different tresholds for exposure to that stuff, and after oversaturating them for some time, there is no buffer available anymore?
Resulting in https://en.wikipedia.org/wiki/Multiple_chemical_sensitivity