Table 2 The effect of an elastic band worn over the beard on the fitted filtration efficiency of various face masks.

From: Assessing the effect of beard hair lengths on face masks used as personal protective equipment during the COVID-19 pandemic

Mask (brand)

Yoga band

% FFE (SD)a

N95 respirator (3M, 8210)

No

85.3 (3.1)

Yes

96.1 (0.6)

% improvementb

+12.7

KF94 micro-dust protection mask (Dr Puri)

No

61.9 (6.7)

Yes

80.2 (3.8)

% improvementb

+29.6

KN95 folding particle protection disposable mask (Lei Shi De)

No

54.9 (7.9)

Yes

65.7 (5.7)

% improvementb

+19.8

Procedure mask, earloop (Medline Industries)

No

30.6 (10.4)

Yes

36.6 (7.7)

% improvementb

+19.7

Cloth/cotton mask (Hanesbrands)

No

39.4 (7.3)

Yes

40.6 (8.0)

% improvementb

+2.9

  1. aThe efficiency (FFE) is calculated as [1 – (mask count/ambient count)] × 100 across the length of the test. The FFE ± SD are shown. The average of at least two unique tests is presented.
  2. b% improvement was calculated as the percentage increase of FFE with and without the elastic band.
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