Yeah, if the allergen is heavy, then air purifiers would not help.....coz then it would not float.
For dust mite droppings, they go down to 10 microns (upper range 40-50 microns) so they do float quite a fair amt. And one does toss and turn during the night. So in this case, it helps quite a fair bit as it's a significant contributor.
Just share a source that I have come across last time
http://www.nchh.org/Portals/0/Contents/Article0243.pdf
In cultures, more than 95% of mite allergen Der
p 1 was associated with mite feces (mean diameter of 22
± 6 mm; range, 10 to 40 mm).1 Domestic air sampling in
bedrooms during dust disturbance showed that greater
than 80% of detectable Der p 1 was associated with particles
larger than 10 um and only a small proportion with
particles smaller than 5 um, the identity of which is not
known.
In summary, we have identified feces, fibers, and
flakes as sources of inhaled mite aeroallergen. Although
the majority of allergen is carried on larger particles,
some is carried on smaller particles and on heterologous
particles, which behave aerodynamically as small particles.
These particles could be inhaled more readily into
the lungs and cause airway inflammation.
-------------------------------
Also, it makes sense that 10 microns might reach slightly mid portions of the lungs. But 40/50 microns have no issue hitting the nasal passages.
So, in this way, asthmatic trigger incidences would not be exactly the same as allergic rhinitis trigger incidences, for dust mite droppings.
In any case, for the first few weeks of "Air purifier theraphy", it is always good to blow your body and face with a fan, let the airflow carry the allergens away, then the air purifier lower the in-room concentration. And as advised above, a 5X ACH or 8-10ACH is needed, depending on severity.
Once your inflamed sites at your respiratory tract is healed, you'd find that a much higher trigger level would be needed before you get symptoms of the allergy, ie you are not as sensitive. Hence, you'd have "recovered". I put "" quotes coz in real life you'd never recover to the level that is enjoyed by non-sufferers, just to a level that is much better so that you can have a higher quality of life and not rely on antihistamines, some of which are drowsy (1st gen) coz the non-drowsy ones are slightly less effective.
And I have come across a few in which they are so jialuck and hypersensitive that 2 x chloropheniramine also CMI (not advisable to take 2 tabs actually).
