Do you think the Nasal Air Filter for hay fever is safe to use?

I suffer from hay fever. I have just read you can buy Nasal Air filters to protect small particles of pollen getting into your nose. It sounds good. But I don't know why my GP never advised me about it actually none of the hay fever websites recommend the use of nasal filters. Is it anything wrong? I understand filters can get blogged but you can just clean it or replace it so why they are not more publicised? if anyone of you knows anything please reply to me. Thanks very much.