Airplanes Refresh Cabin Air 20 Times an Hour
March 11, 2010 at 3:12 am Chad Upton 4 comments
I was on an airplane a couple days ago and the person in front of me was coughing a lot, they sounded really sick.
I was just starting my vacation and the last thing I wanted was to get sick. So, I couldn’t help thinking about being trapped on the plane for the next four hours, breathing the same air as them.
I started to think about the air quality in general. I mean, people always talk about how bad jetliner air quality is, but I really didn’t know much about it.
I did some research and the air quality on planes, at least newer ones, seems pretty good.
Firstly, the air is not circulated from front to back, it is circulated side to side. That means you’re mostly sharing the air with the people in your immediate area, not the entire plane, which reduces the spread of germs.
Secondly, newer planes also use HEPA filters to make the recirculated air is as clean as possible. Hospitals use these same filters to reduce the spread of germs.
Thirdly, fresh air is constantly added. Some air that passes through the jet engines is extracted from the compressor stage, cooled and mixed with the filtered air in the cabin. Stale air is expelled from the bottom of the plane to make room for the fresh air.
In early jet liners, people smoked throughout the flight and at that time much more fresh air was brought into the cabins, but that made the engines very inefficient. The air systems today are designed to exchange slightly more air than the passengers consume, which keeps the oxygen level optimal. This balance also ensures the best possible fuel economy.
The air is refreshed about 20 times per hour, which is even better than most modern office buildings which refresh air about 12 times per hour.
One caveat is while air planes are at the gate. Because the jet engines aren’t running, the air inside is not being refreshed with new air during that time.
There are studies that suggest an increase of sickness with air travel, but experts are quick to dismiss air quality as the primary cause. It is believed this correlation could be caused by other travel related variables such as added stress and less rest.
Broken Secrets
Written By: Chad Upton
Sources: Boeing, NY Daily News, UC SF
Entry filed under: Demystified, Travel. Tags: air, airplane, compressor, engine, fresh, jet, oxygen, plane, quality.
Broken Secrets 
1.
Mr. P | March 14, 2010 at 11:23 pm
I still find my first breath in the airport deeply satisfying. That air may be cleaner than it used to be (at least no one smokes!), but it’s still cold and stiff and unsatisfying to breathe.
My lungs are used to a much more natural air.
2.
KC | April 14, 2010 at 12:20 pm
This reinforces a theory I have that when people get sick while traveling, it’s not because of the plane as most people think, it’s because of the hotel room, airport, and other unfamilar germs and allergens that they encounter around the flight.
There’s got to be another broken secret in there somewhere…
3.
No. | July 2, 2012 at 11:09 am
no! definitely not! That airplane has had millions of people from everywhere touching on it. I have flown on long haul international flights for 20 years now, and I have never seen anything more disgusting in my lifetime than airplanes. Grubby contaminated hands constantly finger buttons, controllers and bathroom handles. People rarely wash their hands and sit down and grab that inflight movie remote. That person could come from deep in the jungle of Africa where they have antibiotic resistant TB…who knows? That is the same one you are touching, eating your peanuts with your hands assuming that only airports and hotel rooms get you sick, not the airplane. With that theory, get ready to get sick, mister!
4.
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