Figure 4

Percent change in median particle emission rate (N) for 10 participants compared to no-mask median, while wearing different mask types and while breathing (blue points), talking (red points), or coughing (green points), for particles in the following size ranges: (a) smallest, 0.3–0.5 µm; (b) intermediate, 0.5–1 µm; (c) largest, 1–20 µm; and (d) all sizes, 0.3–20 µm. The dashed lines are to guide the eye. Surg.: surgical; KN95: unvented KN95; SL-P: single-layer paper towel; U-SL-T: unwashed single-layer cotton t-shirt; U-DL-T: unwashed double-layer cotton t-shirt.