In 2020 millions of people are worried about coronavirus COVID-19 (watch this amazing video comparing it to SARS and the Swine Flu) and refusing the fly, but for the wrong reasons.  People are not traveling because they are worried about their fellow man (or woman!), but because they are worried about becoming infected themselves.

It is a well known fact that if one person is sick on a plane, everyone will be exposed to the infection because a planes ventilation system moves the germs around; right.  Wrong.  Comercial airliners do recirculate untreated air through out the cabin.

According to the World Health Organization, airplane air is cleaner than trains or buses because airplanes cycle their air out faster and use high end cleaning systems to keep their staff and customers breathing fresh air.  By US law, cabin pressure has to be maintained at .25Kb/min (.55lb/min) and to make that work, about 50% of their inside a planes cabin is constantly ejected from the plane.  This translates to all of the air inside a plane cabin being cycled out completely, 25+ times per hour.

airplane cabin air cirulation and filtration system

Here is a statement from Boeing in 2016, well before the COVID-19 outbreak:

Boeing Hepa Air Filter“…Boeing currently uses two types of technology to supply outside air to the airplane. Most aircraft in use around the world today use bleed air systems to ventilate and pressurize the cabin. Bleed air systems have been in use for many decades. In a bleed air system, a small percentage of the compressed air in the compressor section of the engine is diverted, or “bled,” off the engine upstream from the combustion chamber where fuel is added. Outside air is always entering the environmental control system and is constantly circulating in the cabin.

One-half of the air supplied to the cabin comes from the bleed air system, and the other half is recirculated from the cabin itself. Before this recirculated air is returned to the cabin, it is drawn through HEPA filters which remove over 99% of any particulate matter that may be present.

The only modern jet aircraft that does not use bleed air to supply ventilation to the cabin is the Boeing 787 Dreamliner. The 787 uses electric compressors to feed the environmental control system, mixing fresh, outside air and HEPA-filtered recirculating air…

To meet the standards, air contamination filters are used as follows:

Air ContaminantAirplane Solution
Viruses, Bacteria & FungiHEPA filters with microbial efficiency of GREATER THAN 99.999%
Dust & FibersHEPA filters efficiency of GREATER THAN 99.97% Dust and 99.99% for submicron particles
Odors, Volatile Organic CompoundsAdsorbent filters (not absorbent – Adsorbent occurs at the molecular level)
OzoneAdsorbent filters and Catalytic Converters

There is also anecdotal evidence to support this.  If viruses and germs are recirculating throughout the cabin, why are the pilots and stewards not constantly sick?

Airplanes also do not circulate air throughout the entire plane; the cabin is divided into ventilation zones.   This ensures that air is only shared by the people immediately around you.  This fact explains why the Canadian Government decided to notify and test people within 6 feet of a person later found to be infected with COVID-19 on a flight from China.

Airplane ventilation system explained changed 25 times per hour

Watch this short video from 2017 explaining the zones and the science behind why you should ALWAYS leave the overhead air vent turned on when you fly:


That is not correct.  What we can say is that being on a plane is better than being in almost any other populated venue.  If you are worried about infections, you would be better off on a plane than being at a stadium, on a crowded bus/train, elevator, busy hospital emergency room.

Just yesterday we saw this headline “You are no more likely to get coronavirus on an airplane than in any other crowded space”

If you take the normal hygienic precautions (don’t open an overhead compartment and then wipe you eye with the same hand!), you need to worried only about the 6 to 12 people people sitting adjacent to you in a plane.

Surely there are differences in the application of these air quality standards from plane type to plane type (Boeing 737 vs Airbus A320) and ventilation system maintenance from company to company (Air China vs British Air).  Just like your home heating furnace air filter, for instance, HEPA filters do no good if they are not periodically changed.

This site has a focus on China and we know from past tragedies that China’s airlines have had a poor safety record.  However, we have also see the Chinese government take very decisive (some say draconian… watch THIS video of doors being weld shut to lock infected people inside) actions in the fight against coronavirus COVID-19.  Given these two opposing facts, we just can’t say how careful Chinese airlines are going to be.   On the other hand, we can say that “western” airlines like Delta, WestJet, United, Air Canada, Lufthansa, British Airways, KLM and American are going to take this very seriously and ensure their air ventilation systems are well maintained.



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