aeroengineer

So how well is the air filtered on the typical airliner? Getting the flying public confident in flying again means they have to believe that they're not inhaling a bunch of potential pathogens. Of course people packed shoulder to shoulder doesn't help in the prevention of spreading germs either. I suspect there will be a fundamental paradigm shift in this area going forward.

GoFast8

Im no mechanic but Im pretty confident that the air filtration in a typical airliner is basically nonexistent.

Av8tr1

My understanding is there is a pretty hefty HEPA filter for the bleed air coming in. So the vent air should be good?

Cabin air is completely refreshed 20 times per hour, compared with just 12 times per hour in an office building. On most aircraft, air is also circulated through hospital-grade HEPA filters, which remove 99.97 percent of bacteria, as well as the airborne particles that viruses use for transport Additionally, cabins are divided into separate ventilation sections about every seven rows of seats, which means that you share air only with those in your immediate environment and not with the guy who’s coughing up a lung ten rows back.

https://www.tripsavvy.com/air-qualit...r-flight-54164

http://hasmak.com.tr/puro/FAA-PMA%20...eplacement.pdf

https://aerospace.pall.com/en/commer...iltration.html

https://www.faa.gov/data_research/re...dia/201520.pdf

aeroengineer

Thanks for the information. I'm not really familiar with civilian environmental control systems. Glad they have those systems in place for sure. Of course the whole process of air travel is not "social distance" friendly and like the fundamental overhaul of security after 9-11 we'll have to really look at how to make the system from check-in to baggage claim better overall. On another note most articles( https://www.sciencedaily.com/release...0317175442.htm ) are saying this virus was a naturally occurring mutation from a virus in bats and or pangolins . How it got from bats or some other animal to humans is the big question. The danger is if there's an intermediate host that helps it make the jump to humans the virus can die down for a while until it makes the jump back to humans again and we're back on the roller coaster. I think endangered or not exterminating them may be the best course of action. Bat's and Pangolins that is not humans. LOL

rickair7777

For a PAX, air comes into the cabin from above and is exhausted below you at foot-level.

That air is then recirculated through a HEPA filter, mixed with bleed air via the backs, and sent back to you. Repeat.

Some cabin air is exhausted overboard via outflows or small leaks around door seals, etc. That's why there's continuous inflow from the packs.

So the air you're getting is either bleed air (outside air further sanitized by engine compressor temps) or cabin air recirced through a HEPA filter. Your seat-mate could still cough in your face, but you won't be getting anything from the HVAC.

The pack outlet might or might not have a different filter to adsorb any fumes from the engine/APU.

kevbo

The duct and filter installation is very good on a brand new airplane. The filters get changed after there is about an inch dust on them. All the ducting is ripped apart at overhaul and haphazardly reinstalled. After a decade they are really nasty inside. This was back when the airlines did their own work in house. The South American shops that everyone use now are surely better!

kevbo

A paradigm shift would include some attention to detail at overhaul and changing the filter more than once annually. These are the same type of management that decided it would be a good idea to grease an MD80 jack screw once annually, we all know how that turned out.. Anyway, I always wore a respirator, it was just like changing a full vacuum cleaner bag that was torn open.