If you are in the SF bay area, LA, Australia, or another place with wildfire smoke problems, the 3M filtrete MPR 1900 filters with a fan is close to ideal. All

If you are in the SF bay area, LA, Australia, or another place with wildfire smoke problems, the 3M filtrete MPR 1900 filters with a fan is close to ideal. All the smoke uses up a lot of filter material, and this alternative has 10x cheaper filter replacement. It also moves a lot more air through a lot more filter, cleaning everything up more quickly. And the lack of aesthetics is fine for a few weeks. It's worth doing even if you rock a normal filter most of the year. For an upgrade use a few silent computer case fans instead and you can have a super quiet setup to run all day.