I have diagnosed non-allergic rhinitis (I was tested for allergies and none were found). I got so stuffed up that I experienced vertigo at work and couldn't move from lying on the floor.
I was told by the ENT to do nasal washes with boiled water (with added canning salt and baking soda) twice a day. Also, I was prescribed was a nasal steroid twice a day.
When I have a cold or my ears are ringing and the above methods are not enough, I use a non-prescription nasal decongestant before I use the nasal rinse (Neil Med plastic bottle).Not to be used more than 3 days in a row because of rebound congestion.
I have an air purifier and I use it when the air quality is poor during fires mainly or if there are cooking or other strong odors.
I don't know how much difference an air purifier makes otherwise to me because I react, it seems, to particles in fresh air, scents, a lot of things. Windy high pollen days outdoors warrant an N95 mask, not because I'm allergic to pollen, but simply because it's gunk in the air.
It might be worthwhile to try to see an ears, nose, and throat specialist (ENT) to rule out allergies and work up a plan.