Air travel plays a critical role in the way modern diseases spread. Cramped quarters. Long hours. People sniffling, sneezing, and generally spreading their germs around. It’s no wonder air travel has contributed to outbreaks of deadly illnesses like tuberculosis, norovirus, and SARS. During 2014’s Ebola epidemic, hundreds of flights were grounded as a precaution.
But new research from Florida State University published in Physical Review suggests that flight boarding processes could be redesigned to reduce transmission of disease. Rather than the multiple zone boarding procedures many airlines employ today, FSU associate professor Ashok Srinivasan found that a two-zone system where passengers on each side of the plane board at random is less likely to spread disease. It’s a reminder that redesigning something as small as plane boarding procedure could contribute to improving large-scale problems like global health–even if fliers have to wait a little longer to board their planes.
In the study, Srinivasan and his team used supercomputers to simulate four different types of boarding (random, two sections, three sections, and by column) and how infection spreads based on each system.
They found that the most common boarding process actually spread the most disease. This familiar, multitiered zone system, where passengers board in three or more groups at the same time as the other people sitting in their section, was the worst offender because more people tend to stand closely together while waiting to board and find their seats, so there’s more opportunity for contact. It’s an unsettling finding, given that this is the most common boarding method used on flights right now. The researchers also modeled different sizes of airplanes, and found that disease is more likely to spread on large airplanes versus small airplanes, also as a result of the large number of people in close proximity.
The multi-zone system’s biggest problem is that it puts more people in closer contact, so the solution to reducing disease transmission is in boarding procedures that that lessen contact. In essence, random boarding is key. While passengers might enter the plane itself in closer quarters, they would likely be seated farther apart, which would prevent clustering and reduce disease transmission. According to the researchers’ models, using either entirely random boarding or two-zone boarding (where people board randomly within each zone) would have a significant impact on how diseases spread on airplanes during an epidemic.
How big of an impact could changing the boarding process have during an outbreak? If another Ebola outbreak occurred and current boarding procedures were kept in place, there would be a 67% chance of more than 20 infections per month transmitted purely through proximity while boarding an airplane. But if smaller planes were used and two-zone, randomized boarding implemented, there would be only be a 13% chance of that happening.
Unfortunately, so many airlines use today’s multi-zone system because it’s simply more efficient. Srinivasan proposes making health the higher priority, despite the emphasis airlines put on efficiency in a bid to maximize their profits. “On the whole, random boarding does take longer, but if passengers had to choose between getting Ebola and being seated a few minutes later, we suspect they’d prefer the latter,” Srinivasan said in a statement.
Changing procedures now, before the next epidemic, could also be crucial. People tend to panic during outbreaks at the scale of the Ebola epidemic in 2014, particularly with regard to air travel. That can cause airlines to ground planes to and from places where people have been diagnosed, which can halt aid and impact affected countries’ economies, worsening the spread of the disease. As a result, in 2014 the Obama administration refused to implement a travel ban even after an infected individual boarded a flight from Liberia and traveled to Nigeria. Better boarding procedures could mean that there’s a smaller chance of any disease spreading on an airplane, and thus less of a reason to ground planes during an epidemic in the first place.
The only thing standing in the way? Convincing airlines to willingly become less efficient.