Thread by @nytimes

How safe is flying? The air in planes is refreshed more often than most grocery stores. But that doesn’t guarantee it's completely free of Covid-19.

Watch how air moves through a plane, and see what it means for the risk of flying now. nyti.ms/2QABXM2

With the help of researchers, we simulated more than two million air particles to understand how they flow. At any given moment inside the cabin, you’re breathing a mixture of fresh and refreshed air that’s been filtered. nyti.ms/2QABXM2

This is what happens when someone wearing a mask sneezes on board.

Not all particles are the same size, and most don’t contain infectious viral matter. But if passengers nearby weren’t wearing a mask, the sneezed air could increase their chances of inhaling viral particles.

To prevent air from spreading through the cabin, the plane's ventilation system keeps particles contained to a few rows. Air is refreshed every two to three minutes inside the cabin. nyti.ms/2QABXM2

The ventilation system is integral to how plane files. The engines constantly suck in outside air as they propel the plane through the air.

That air is pressurized and conditioned as it snakes from the engine into the plane, eventually reaching the cabin. nyti.ms/2QABXM2

The air in planes is not the only part of traveling safely, however, experts say.

The exposure risk may be just as high, if not higher before passengers ever board — going through security, in the terminal or visiting restaurants.

See more here: nyti.ms/2QABXM2