Does anyone know how the air quality is? I'll be there next week and I'm concerned about the smoke. Also, is the park under any threat of fire itself?

Silver Falls isnt effected by the fire - so you will find this park open, you won't find any smoke. Mind that many other regions were closed due to wild fire , places including crater lake, proxy falls, Multnomah falls, Bridal veil , Vista house etc were closed (i was there on sep 21,22,23 dates) unfortunately all of them roads were closed except silver falls.

I was there about two weeks ago and there was no smoke what so ever. It was perfect. I highly doubt it but you can always go into their website and check that. Hope that helps