One of the comments I read said
"The product details doesn't tell you about the size of particles that this purifier can trap. Only after opening the box and reading the manual, I realized that it filters particles 'as small as 2 microns'."
Since it's not reported on the amazon page I can return the item if I see that it doesn't work for the birds' dander, and go for the other one. I hope not because I was getting attached to the idea of the washable filters and the tower shape

I will let you know how it goes! The tracking tells me that it's already in transit so I should get it tomorrow.