This month: HEPA filtration
OK, so I’ve never heard of this. What is it?
HEPA is an acronym for high-efficiency particulate air. To be classed as HEPA in Europe, a filtration system must remove at least 99.95% of particles whose diameter is equal to 0.3μm from the air passing through it.
Where are these filters used?
All sorts of places – from vacuum cleaners to air conditioning systems in buildings to (the one we are interested in today) airliners.
Why are we interested in planes?
A commentary in the Journal of the Royal Society of Medicine states that improving air quality in classroom spaces should be as important as following government advice regarding social distancing, mask-wearing and hand washing. It points to lessons learned from the airline industry.
What are the lessons?
The risk of contracting COVID-19 on a flight is currently lower than in an office building or classroom. Kaveh Asanati, lead author of the paper, said: “The strategy includes testing passengers, the use of face coverings or masks, hygiene measures and, more importantly, maintaining clean air by circulating a mix of fresh air and recycled air through HEPA filters.”
What does the commentary recommend?
A potential practical option for schools would be the use of portable HEPA filtration units.
If schools don’t have these units, what should they do?
Keeping doors and windows open – for as much as is reasonably practicable – seems to be the best way forward, they write.
