The smallest of pollen grains (~0.6 microns) and other allergens should be trapped by a HEPA filter, however what happens when these decay / break apart? Is the allergen the whole pollen grain or are the allergens really the proteins that make up the grain (which by themselves would be too small for the filter to hold)?
Just wondering because the measures I implemented a couple of months ago (air purifier + a window screen made of polypropylene) seem to have been effective at first, but now it seems to be worse in the "controlled environment" than elsewhere. It's difficult to say for sure, but I was wondering if this theory holds any weight. Could it be that the various allergens trapped in the screen and air purifier are now breaking down and passing through the filtration?
The closest thing to an answer I could find is this: