Jeff Kaufman proposes combining a sound-masking fan with filtration so one device also removes airborne particles. His small-device example delivers 34 CFM of clean air at about 45 dB; larger devices can clean different amounts at the same noise level. The estimate of indoor particle concentration falling to 16% of the outdoor level assumes a 10-by-10-foot room, an 8-foot ceiling and 0.5 outdoor air changes per hour. The manufacturer’s documentation confirms three-stage filtration, but the essay is not a clinical trial demonstrating better sleep or infection prevention.