As travel restrictions are being gradually lifted during the coronavirus pandemic, the Mainichi Shimbun answers some common questions readers may have about ventilation on airplanes and bullet trains.
Question: I heard that the number of flights has greatly reduced due to the coronavirus. Is that right?
Answer: Yes, there have been almost no international flights in service since late March. Japan Airlines Co. (JAL) and All Nippon Airways Co. (ANA) have also been operating reduced domestic flights services, with departures down between 15% and 40% of their usual amount since late April. But, operations on some routes have resumed since Japan's state of emergency was lifted in late May.
Q: Aircraft cabins look enclosed, but are they ventilated?
A: According to JAL and other sources, the air inside a plane is wholly replaced about every two to three minutes. External air enters in large amounts from the engines, and air conditioning equipment then circulates in the cabin from the ceiling to the floor. Half of the air is expelled outside, while the other half goes through a high-performance filter and reenters the cabin space with new air from outside. The same kind of filter is used in operating rooms, and they can almost completely remove particles with a diameter of as small as 0.3 micrometers. The diameter of droplets dispersed when coughing is said to be around 5 micrometers.
Q: What about bullet trains?
A: In May, the number of bullet train services on the Tokaido Shinkansen Line decreased to 60% of the amount run in May 2019, but the numbers rebounded to as high as 80% compared to last year upon entering June. It takes six to eight minutes to replace the air inside a bullet train with air from outside. External air is taken in from ventilation devices attached to each car, and is piped in from under the overhead luggage storage bins. The air is then collected from the floor under the seats, and a portion dispelled outside, while other parts of it are circulated again after being put through a filter.
Q: Isn't it a bit worrying if you're sitting next to other passengers in an airplane or bullet train?
A: JAL has taken measures to prevent people from being seated next to each other by not allowing customers to reserve seats in the middle of banks of three to four connected seats, and by making only the window seats available in rows of two until the end of June. Meanwhile, the Central Japan Railway Co. advises that users should choose seats that are at a distance from other passengers, but families still have the option of sitting next to each other if they choose to. The company is also responding flexibly to seat changes after boarding.
(Japanese original by Yuichi Utsunomiya, Osaka Business News Department)