PS - Air purifiers are good for allergies. But that negative ION crap has been around a while and has not proved out well. I was researching it 10 years ago before I got diagnosed with Chronic Fatigue Syndrome not at all connected to CRT's Flourescent lighting, etc. It used to be a remedy for VODs Video (CRT) display disorder depression and fatigue.
An interesting side-bar - when I lived in Seattle - even grayer than portland - I used to race sailboats year-round. I'd be outside at least 2 weekends a month. I didn't have any problems then. I think it was because I was outside often and getting real sunlight even cloud-filtered that accounts for the relief, along with winter exercise and fresh air.
Good luck!
Dont worry, Beee happyyyy!
Bren