Plane air con gets a bad rep.

It's usually assumed that by switching it on you're subjecting yourself to all the manky, germ-infused air that's been floating around the rest of the cabin. Or that if you're warm, you'll just end up making yourself too cold, and be uncomfortable for the entirety of your trip. Either or. But apparently, there's a very good reason to keep your plane air conditioning switched on during your flight - and it's to do with avoiding germs, not coming into contact with them. According to Dr. Mark Gendreau, air con's bad reputation is "completely unfounded." And Dr. Gendreau knows his stuff. He's an expert on the spread of infectious diseases via air travel, after all. Speaking to Travel and Leisure magazine, he said that it's better to leave the air con vent open during your flight, rather than closed.

"As a rule of thumb, the air that you’re typically breathing and exposed to is usually anywhere from two to five rows surrounding your seat. For airborne viruses, it is incredibly important to ventilate, since ventilation becomes your main means of control besides isolating the affected person."

Although the air on most planes is filtered and cleaned every couple of minutes, Dr. Gendreau has suggested that not all of the dust and microbes are totally removed this way. He said that viruses have the ability to hang around in the air for up to five hours, but using the air con vent helps combat this. The vent actually creates a "barrier" around the person sitting below it, stopping these particles from floating around our heads for longer than they need to. We'll think twice about switching them off next time we're on a plane.