Aura™ FFP3 disposable particulate respirator mask, 1863, flat-fold, 3-panel design, with red rubber straps, of the type used by healthcare workers during the COVID-19 pandemic, 3M, 2019-2020

Doctor Georgina Clarke wore this FFP3 respirator during face fit testing in March 2020. When appropriately fitted and worn correctly, an FFP3 mask reduces exposure to airborne particles by a factor of 20. The abbreviation FFP stands for ‘filtering facepiece’. Three classes – FFP1, FFP2 and FFP3 – offer increasing degrees of protection to the wearer according to the level of risk they are exposed to.

Fit testing is performed by releasing a bitter or sweet spray into a testing hood. First, a sensitivity test is conducted without a mask to ensure you can taste the substance at sufficiently low levels. Then you are asked to carry out a series of movements while wearing the mask to check the seal remains intact. If you can taste the spray, the fit is deemed unsuitable. The test must be repeated any time the user wishes (or is required to) wear a different make or model of respirator.

This example was one of several Clarke was tested with while working in A&E at Darlington Memorial Hospital. It was declared safe for her to use and became her preferred choice as it offered the most comfortable fit.

Clarke recalled: ‘we would frequently be changing brands of the FFP3 masks as stocks would run out and we would need to swap [to] an alternative … but that would mean you would have to be ‘fit tested’ again for each new mask. Which was a bit frustrating as it was time consuming.’