skip to primary navigation skip to content
Home

Studying at Cambridge

Respiratory Protection Engineering Task Force

 

Frequently Asked Questions 

Questions about Mask Fit

Fit

How can I check if my mask fits? (for tight-fitting masks) 

Short Answer: If you have a tight-fitting face mask, like an N95/99/100, FFP3/2/1, or elastomeric respirator, you can check the fit of your mask using a qualitative or quantitative fit test or by performing a fit check.

Long Answer: If you have a tight-fitting face mask, like an N95/99/100, FFP3/2/1, or elastomeric respirator, you can check the fit of your mask using a qualitative or quantitative fit test or by performing a fit check. Fit checks have become a popular way to check mask fit since COVID-19, because it has become costly and difficult for hospitals and companies to obtain the supplies needed for qualitative or quantitative fit testing. However, our research indicates that fit checks are unreliable. Quantitative fit testing is highly reliable but requires equipment costing tens of thousands of dollars. Qualitative fit testing is less reliable than quantitative fit testing, but much less expensive method of assessing fit and more reliable than fit checking. There is no NIOSH approved way to perform a qualitative fit check without a commercial kit. However, for those who feel it is worth the risk, we have devised a way to perform a qualitative fit check with a few inexpensive components you can buy on Amazon. We would like to stress that the safety of this method has not been ascertained. Please move forward at your own risk.

Read more
n95 masks 

Do N95 masks protect you from 95% of particles? 

Short Answer: An N95 mask will protect you from 95% or more non-oil based particles ONLY IF it fits you.

Long Answer: In the USA, N95 masks are regulated by the National Institute for Occupational Health and Safety (NIOSH). NIOSH tests respiratory protection devices and assigns them a class based on the amount of filtration they provide from particles (95%, 99%, 100%) and the ability of the filter to reduce oil (N = not resistant to oil, R = partially resistant, P = oil proof). However, NIOSH is not guaranteeing that the face mask will fit you or any single individual. Each person has a unique face shape, which changes how masks fit. While one model of N95 mask might fit you, another model, even from the same manufacturer, might not fit. If the mask does not fit, it may not offer you protection from the stated percentage of particles. So, if it doesn’t fit you well, a NIOSH approved N95 mask might only protect you from, say, 50% of particles.

Study at Cambridge

About the University

Research at Cambridge