Mask VS Respirator


In day to day language we often say mask, when referring to what are technically called respirators. Uses for Masks:

  • Masks are loose fitting, covering the nose and mouth
  • Designed for one way protection, to capture bodily fluid leaving the wearer
  • Example – worn during surgery to prevent coughing, sneezing, etc on the vulnerable patient
  • Contrary to belief, masks are NOT designed to protect the wearer
  • The vast majority of masks do not have a safety rating assigned to them (e.g. NIOSH or EN)
Uses for Respirators:
  • Respirators are tight fitting masks, designed to create a facial seal
  • Non-valved respirators provide good two way protection, by filtering both inflow and outflow of air
  • These are designed protect the wearer (when worn properly), up to the safety rating of the mask
  • Available as disposable, half face or full face
Respirator Standards
  • Whilst surgical style masks are not redundant by any means (discussed more below), they aren’t designed to protect the wearer, whilst respirators are.
  • The US Center for Disease Control (CDC) cites the N95 respirator standard as part of the advised protective equipment in their Covid-19 FAQ and their SARS guidance (SARS being a similar type of Corona virus). Which suggests that an N95 or better respirator is acceptable.




N95 vs FFP3 & FFP2


  • The most commonly discussed respirator type is N95. This is an American standard managed by NIOSH – part of the Center for Disease Control (CDC).
  • Europe uses two different standards. The “filtering face piece” score (FFP) comes from EN standard 149:2001. Then EN 143 standard covers P1/P2/P3 ratings. Both standards are maintained by CEN (European Committee for Standardization).
  • As you can see, the closest European equivalent to N95 are FFP2 / P2 rated respirators, which are rated at 94%, compared to the 95% of N95.
  • Similarly, the closest to N100 are P3 rated respirators – with FFP3 following closely behind.




KN95 vs N95


  • According to 3M (source), the Chinese KN95 standard has an equivalent specification to N95/FFP2 respirators . To quote:
  • “It is reasonable to consider China KN95, AS/NZ P2, Korea 1st Class, and Japan DS FFRs as equivalent to US NIOSH N95 and European FFP2 respirators”
  • In practice the issue is more complex, and I wouldn’t take for granted that all KN95 respirators are up to the same standard.
  • Things to watch out for:
  • Typically KN95 respirators are held in place by over-ear elastic loops, rather than behind the head elastics. This can result in a weaker seal. Fortunately there are methods for tightening – see this YouTube video for ideas. Products called “ear savers” can also aid with tightening, and can be found on eBay or you can 3D print them.
  • There’s no guarantee that all KN95 respirators actually meet the Chinese KN95 standard. However, with the current respirator shortage, unfortunately the same goes for N95/FFP also.




How big is the Coronavirus, and can respirators filter it?


A recent paper shows that the coronavirus ranges from between 0.06 and 0.14 microns in size. Note that the paper refers to the coronavirus particle as 2019-nCoV, which was it’s old name. The virus is currently called SARS-CoV-2, and the illness it presents in people is called Covid-19.




Surgical Masks


  • Surgical masks are generally speaking a 3-ply (three layer) design, with 2 sheets of “non-woven” fabric sandwiching a “melt-blown” layer in the middle. It’s the melt-blown layer that provides the filtering capability. A melt-blown material is also used in respirators, and thus you can imagine it’s more expensive and hard to come by recently, due to demand.
  • The melt-blown fabric is made by melting a plastic, then blowing it from either side at high velocity onto a rotating barrel. Done right, this results in a fabric composed of tiny filaments.




Can Surgical Masks Filter the coronavirus ?


  • Whilst FFP2/FFP3 or N95/N100 are the gold standardas far as face protection goes, what about surgical masks, do they provide any protection?
  • Strictly speaking, surgical masks are primarilydesigned to protect vulnerable patients from medical professionals. Stopping the wearer (e.g. surgeon) from spreading their germs when coughing/sneezing/speaking. So they’re designed to protect patients, not to protect the wearer.
  • An obvious flaw with surgical masks compared to respirators is their lack of a tight face fit, which leaves gaps around the edges.
  • There isn’t currently research available on the efficacy of surgical masks (or even respirators), for protecting wearers against the coronavirus. Although this isn’t totally surprising given how new the virus is.
  • In lieu of that, the below looks at research around the use of surgical masks and N95 masks in the context of influenza, looking specifically at the protection given to the wearers. Influenza may be a good virus particle to compare it to, as they are both transmissible through droplets and aerosol, both cause respiratory infection, and both are similar in particle size.
  • N.B. Please don’t conflate the comparison to the influenza particle as suggestion that they are comparable illnesses – current data suggests that the coronavirus may have a higher mortality rate.




Important Hygiene Measures


  • Alcohol Based Hand Sanitizer - The CDC recommend that if soap and water are not available, use an alcohol-based hand sanitizer with approximately 70% alcohol. For effectiveness, you need to wait for the alcohol to fully air dry. Interestingly, alcohol contents above 90% are regarded as less effective (source).
  • Sanitize your phone and other items you touch regularly - Given how often we use our phones, this seems like the next logical priority to be sanitized. Using antibacterial wipes or alcohol swabs (typically 70% alcohol) to clean your phone and other items is a good option. If the antibacterial wipes claim to be able to kill the flu virus (H1N1) – that’s a good sign they may be able to do similar for the coronavirus. Once finished wiping, leave to air dry.
  • Other items to consider include:
  • Computer keyboard and mouse
  • House and car keys
  • Re-usable water bottles
  • Car steering wheel
  • Clothing pockets
  • Door handles
  • And take appropriate caution when interacting with them – sanitizing where possible





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