HEALTH WARNING - HEPA FILTER MASK

PLEASE READ IN FULL (BEFORE YOU COMMENT)!! I know people are very keen to reduce their risks to #Coronavirus #COVID19. I totally get it and its affected my personal family quite significantly. There's been a bit of a "viral craze' around putting #HEPA Filter material into home sewn masks. Short version - Don't bother, not only is is unlikely to be helpful but it may cause you lung problems too.
I know this may be frustrating, as it isn't offering you a much sought after solution, but I think it's only right to highlight the issues so you can make an informed decision.

NB loads of people are asking for an alternative and about different materials. I advise you to contact the relevant manufacturer and tell them what you are proposing and see whether they think it's safe. For example, please see Natalie Moys thread below. She reached out to 3M about the Filtrete Filters, and they advised against it.

I had suggested here that you can still buy n95 PM2.5 replacement filters off Amazon which have several layers of filtration. Whether it can be fulfilled at all, or whether they have reasonable delivery times - I don't know, and some commentators below have indicated that there may be embargoes or shipping delays (may vary where you live). Regardless, whether your airflow will be through it or around it - will depend on things like your masks seal, so I can't guarantee whether it works well.

There is also emerging opinion and advice that even a simple cloth barrier over your face is better than nothing at all. There is a good rationale to this in both 1. Stopping the spread of small virus laden droplets being exhaled 2. forming a partial barrier to inhalation by someone else 3.Simply stopping people touching their face. What the ratio of benefit is compared with a purpose built filter system remains uncertain at this point, but if it does - I'll post it here.

Best wishes and only good health to all, Simon.