A $47 air purifier beats your white noise machine at its own game
Air Purifiers as White Noise Machines
White noise machines are just fans spinning in a box. Jeff Kaufman points out that the same fan could be pulling air through a filter instead: a small $47 purifier runs at 45dB, cleans 34 CFM, and removes smoke and infectious particles. In a typical 10-foot room it cuts indoor particulate levels to 16% of outdoor levels, roughly taking AQI 200 down to 72. Bigger purifiers clean more air but cost more and look worse.
But a fan is really a great approach; you just need to put it to better use: have the fan clean the air.