A new study by the Department of Defense has discovered that airline passengers face extremely low risk of contracting the novel coronavirus when flying.

Thanks in large part to high air exchange rates on planes and HEPA-filtered recirculation, the research showed that the risk of aerosol spread of the virus was cut 99.7 percent.

On most planes, the air exchange rate is roughly every three minutes and 75 percent comes from outside the plane, which means that only 25 percent of cabin air is recirculated. It takes just six minutes for 99.99 percent of particles to be filtered out of the cabin.

“The 767 and 777 (aircraft) both removed particulate fifteen times faster than a home … and five to six times faster than recommended design specifications for modern hospital operating or patient isolation rooms,” the study wrote.

The study—conducted by a team that included members from United Airlines, Boeing, the University of Nebraska Medical Center, National Strategic Research Institute, and various research firms—was able to complete hundreds of tests aboard United’s Boeing 777 and 767 planes.

The researchers released tracer aerosols from a mannequin that mimicked coughs and traced how they moved throughout the cabin. They gathered data with both the mannequin wearing a mask and not wearing one.

This particular study is seemingly in line with previous research on the safety of flights amid the ongoing pandemic.

In one case, 328 passengers and crew members were tested for the coronavirus after it was revealed that a March 31 flight from the United States to Taiwan had been carrying twelve passengers who were exhibiting coronavirus symptoms.

But when the test results came back, all the other passengers and crew members tested negative.

One professor of statistics at the Massachusetts Institute of Technology made an effort to quantify the coronavirus risk while flying.

According to his findings—based on short-haul flights in the United States on aircraft with three seats on either side of the aisle and with all passengers and crew wearing face masks—the probability of being infected on a full flight is only one in 4,300. Those odds plummet to one in 7,700 if the middle seat is vacant.

Airlines in the United States have taken a huge financial hit for much of the year as the pandemic has caused travelers to cancel or postpone flights. Compared to last year, domestic air travel is down 62 percent and international air travel 79 percent, according to the industry group Airlines for America.

Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.

Image: Reuters