Cultural differences fascinate me, as do superstitions. So naturally I am enthralled by the utter mortal fear Spaniards have for air currents, specifically those running through a house. Every time I open two windows on either side of my house to get a nice current of fresh air running through, I am told to close one of the windows, because air currents (corrientes) are dangerous. When there's a baby or child in the house – forget about it! – the importance of reducing air pressure differentials goes up by several orders of magnitude. Everyone in Spain knows someone who knows someone who knows someone who died because they had fresh air running through their house. In South Korea, they have a similar belief, that an electric fan left running overnight in a closed room will kill any humans in the room. It's called fan death. From anecdotal blog entries I've read, it seems that everyone in South Korea takes this as a widely accepted scientific fact. Yet everyone outside of the country regards it as a silly superstition.
I have spoken with maybe a dozen Spaniards about the dangers of domestic corriente, and they all look at me like I'm an idiot for not knowing this basic scientific fact. When I inquire, I am told that, if you are lying down sleeping under a tree in a field with a light breeze, that's fine. But if you're lying on your couch with the window open and the same exact wind is blowing over you, that is very dangerous and you are putting yourself at risk of a cold or pneumonia. Eliminating variables, I asked if there were walls but no ceiling, would that be okay? Yes. And if there is a ceiling, but no walls? Yes, that's okay, too. But once you have a ceiling and walls with a window open, the air current becomes very dangerous.
There is an important lingual distinction here. When you're outside or don't have a ceiling or walls, that's called viento (wind), but the ceiling and walls turn the same moving air into corriente (current), and I am told that they are not the same thing.
I have done an hour or two of internet research into this concept over the years, and the only thing I've found is that the Italians have a similar fear of moving air. I can't find any articles in Spanish discussing the phenomenon, and the only articles in English discussing air currents in the home, as they relate to danger, are ones about how your moldy old air conditioner might be killing you with mold spores and you need to open up all your windows and get some fresh air flowing before you die. In the States, we have attic fans, which we turn on specifically to create low pressure inside the house to generate a breeze.
My wife claims that she was taught the danger of corrientes in school and will invoke terms like convective heat transfer (why moving air feels cooler) and Bernoulli's principle (why air moves faster through a narrower path) in its defense, but it still doesn't make any sense to me why air moving at the same velocity over your skin outdoors would be any safer. No doubt the Koreans are taught about fan death in school, too.
If this deadly air current phenomenon is real, I would love to understand it, and would convert to a believer in a second with sufficient evidence, but it certainly seems to me like a cultural superstition, heavily laden with confirmation bias…in the same category as not swimming for an hour after eating.
Note that I am not calling Spaniards stupid, just observing this quirky regional belief. No doubt every country has their own version of this. The "no swimming after eating" one, for example, is very prevalent in the United States.