What’s in a Facemask?

In general, there are three types of commonly used, disposable masks.

These are 1) single-use face masks, 2) surgical masks and 3) respirators. Re-usable, often home-made, facemasks are also common, but are not discussed here.

1)      Single-use masks normally have just a single layer, are very thin, and are typically effective only at capturing larger particles such as dust, pollens and the like. They do this quite well.

2)      Surgical mask standards have higher requirements for filtering out virus-sized (0.1 micron) particles, however these standards vary by region – see below. Surgical masks are a much higher quality than single use masks, and mostly 3-ply construction.

3)      Respirators, also called pollution masks, typically capture more than 90% of minute, virus-sized particles and are differently constructed to the other two – they look different and fit differently.

The standards with the lowest requirements on filtration effectiveness are the single-use face masks. While looking similar, single-use masks are not to be confused with surgical masks! Surgical masks have higher requirements, and respirators have the highest requirements. Respirators also usually fit tighter around the face than surgical masks and single-use facemasks.
Each country, or region like the EU, has their own certification standard for different types of mask. For example, Europe uses the EN 14683 standard for surgical masks (Type I, Type II or Type III), whereas the USA has the ASTM F2100 standard (Level 1, Level 2 or Level 3) and China uses the YY 0469 standard. The standards specify the rules and testing methods companies should follow to rate their masks. Each standard varies a little by country, however they are broadly similar / equivalent; one standard is not better or worse than another.

So, which mask should I choose?

There’s a lot in the adage “you get what you pay for”, and respirators made to higher standards do offer better overall filtration of air, but not necessarily better protection from something like Coronavirus.

There’s scientific evidence from three different trials finding that facemasks help prevent viral infection. A surprising and consistent result from all three trials is that surgical masks prevent infection of viruses as well as more sophisticated N95-respirators. Importantly, compared to using no mask, the use of a surgical mask or a respirator reduced the risk of influenza infection by 75%!

Surgical masks seem to offer the best value proposition for protecting you, your loved-ones and those around you during a viral pandemic like Influenza or Covid-19.

REMEMBER: These are disposable masks with limited usable life. They should not be re-used in bacterial or viral environments!