White noise machines are widely used for sound masking, increasing privacy in offices and helping people sleep. The classic approach is a fan in a box, but over the past ten years people have mostly switched to electronic ones. A fan is still a great approach; you just need to put it to better use: have the fan clean the air.
Instead of spinning a fan in free air to make noise, you can have it pull air through a filter. A small purifier sounds a lot like a classic noise machine, is only a bit larger and more expensive, and removes smoke and infectious particles from the air. For example, here's a $47 purifier with a 6.5" diameter, cleaning 34 cubic feet of air per minute ("CADR") at 45 dB. For most circumstances where someone would use a white noise machine, this kind of small purifier is all-around better.
Now, 34 CFM is not very much air cleaning. The author usually runs an Air Fanta 3Pro, which cleans about 6x more air for the same amount of noise, or about 12x more air with much more noise (about 56 dB). On the other hand, it's more expensive ($165) and bulkier (12.6" square), and arguably uglier. Still, even a 34 CFM purifier helps a lot with smoke.
If you have a 10ft square room with an 8ft ceiling and a reasonably typical 0.5 air changes per hour through leakage from outdoors, this small purifier will cut particulate levels to 16% of the outdoor level. In AQI terms (not linear) this is like going from AQI 200 to 72, or AQI 100 to 31.
Source: Hacker News · Summarized by HeadlinesBriefing