I'm not an expert on the statistics about Sequim, just a fairly frequent visitor to the area. Yes, pretty much the entire Olympic Peninsula is "fantastically beautiful", especially, for me, the magical experience of the Quinault Rain Forest. Have you checked City-Data.com's long, all-inclusive statistics page on Sequim?
http://www.city-data.com/city/Sequim-Washington.html
I've never found the air in Sequim unpleasant, or even noticeable, for that matter. There's so much wind in and through Sequim that it seems to me that it keeps the air clean.
Many people from Washington and Oregon and elsewhere have chosen the northern shore area of the Oly Pen for their retirement location. Seems attractive, eh?
I've never experienced a paper mill "presence" in Port Angeles, but then I've never lived there. The only recurring identity I always feel in Port Angeles is the luxurious, seductive fragrance of newly-cut wood. There is a paper mill in Port Townsend which makes a presence that many consider unpleasant known in some areas of that town.