Over the past few weeks, advice on using face masks and respirators to slow the spread of COVID-19 has shifted from general use being discouraged, to a growing push for widespread use–including the use of DIY face masks.
The move makes sense: reducing the potential for infected users to spread the virus through coughs, sneezes, or simply breathing, is important. Yet just because something looks like a mask, doesn’t mean that it works like one.
This is where it’s helpful to have an idea of the science behind how face masks and respirators work, and it’s why we created this short Risk Bites primer:
The primer doesn’t go as far as providing advice on how to make a DIY face mask. But it does give some insights into the science behind making a DIY face mask that is more effective. These include:
- Recognizing that, apart from the largest particles, face masks don’t act like a sieve;
- Using non-woven textiles if possible such as swiffer cloths or blue shop towel (as in this great article); And
- Realizing that air–and the particles it carries–follow the path of least resistance, meaning that if there’s a leak or a gap around the edge of a face mask, that’s where the particles will go.
Of course, masks made out of whatever fabric is available are probably better than nothing (as long as they don’t make it hard to breathe, or don’t end up saturated with infectious droplets), especially where they capture or deflect large droplets from coughs and sneezes.
Yet if you know something about what makes masks work better, it’s easier to make one that’s more likely to protect the user and others, and not just look like it does.
