Do allergens decay/die?
Well, it’s important to understand that it’s the cytoplasmic part of the pollen that causes the allergic reaction. Particles within the pollen grain are released through germination pores, or (quite often) due to bursting. This often occurs after the grain comes into contact with moisture – such as when it touches the inside of your nose. But it also happens after rainfall. So it’s important to realise that even though the pollen counts drop after rain, the allergens are still out there. Indeed, many people have worse reactions after rainfall for just this reason. I have read reports that, after a few weeks, the ability of pollen to expel their cytoplasm is lost, but I think it varies quite a bit depending on the pollen type. It’s conceivable that the smaller, allergen containing materials inside the pollen do not last long after their release (proteins degrade over time, just like pretty much everything else), but I suspect they last quite a long time while they’re still within the po
