Don't Get Desiccated!

It’s the time of year when one half expects to awaken to demonic sounds and screams and, turning on the light, find the cat stuck to the ceiling, it’s little sharp-clawed feet waving comically in the air.

Then, after retrieving it, going to the sink to wash and disinfect one’s wounds and being greeted by a quarter-inch bolt of miniature lightning as he reaches for the faucet.

In addition to its other attributes, winter is a time of low humidity. That gives static electricity opportunity to romp in its annoying way. It does dangerous things, too, such as making it easy for your city to burn down. We’ve joked for decades how January and February are the months of computer malfunctions, but it’s true: Static electricity caused by low humidity causes all kinds of otherwise inexplicable gremlins to invade our electronic devices.

And low humidity makes it a lot easier for you to get sick.

That’s right: it is not the cold weather itself that renders you subject to all kinds of respiratory infections, but instead the dry air.

I’ve written a little about this in the past, but I think we could all use a refresher, as we’ve come to realize that we’re up against a constantly increasing collection of irritating and sometimes dangerous ailments.

Humidity in the winter seems weird at first. The cold air outside gets saturated with water vapor because the colder it is the less water it can hold. But that’s the same air you are breathing inside, where it’s warmer. Warm air can hold a lot more water before it gets saturated. Relative humidity, as it’s called, is a measure of how close the air is to saturation, the point at which it can accept no more evaporated water. So it can be foggy in the cold outside, 100 percent humidity, while inside humidity can be in the 20-30 percent range. The cold air has its fill, while inside the air can accept a lot more water.

Because of that, the air sucks up moisture where it can, and things dry out. Winter air is bad for wooden furniture, house plants, everything affected by static electricity, guitars (!) and other musical instruments, leather goods — you get the idea.

In warm California, the dry air is due to wind blowing down from cold mountainous areas to lower, warmer places, where it exacerbates the likelihood and effect of terrible fires.

So all else being equal, it’s a good idea to humidify the house in the winter, if just to protect your possessions.

But there’s an even more ominous reason to do what you can to keep the air moist. Dry air can make you sick all on its own. Worse, it can help microbes make you sick, very sick, extremely sick, or dead.

“Relative humidity (RH) represents an underestimated outdoor and indoor environmental parameter,” write Italian researchers in a study published in 2023. “Conditions below and above the optimal range could facilitate infectious transmission as well as the exacerbation of respiratory diseases.”

That puts it mildly. If you’re where the humidity is regularly less than 40 percent or more than 60 percent, you’re in danger. “When RH is too low, it can cause dryness and irritation of the respiratory tract and skin, making individuals more susceptible to infections.”

You probably don’t need a study to tell you of winter’s dry throat and skin, particularly unpleasant dry nasal congestion and dry cough and, sometimes, nosebleeds due to dried-out passages in your nose. Excess humidity is not an issue in winter, so we’ll consider only the problems caused by low humidity. These include increased bacterial growth, more viruses and their greater virulence, thickened mucus that’s harder to get rid of and harder to get to do its job, increased skin disease, especially eczema, and dehydrated skin opening new pathways for infection.

Last March, Stanford University reported that low humidity is “why, in many regions of the world, more people tend to get sick with airborne viruses in winter, when heating systems dry out indoor air.”

Said the Stanford researchers, “Indoor relative humidity of 40% to 60% has long been recommended by experts, and now this research points to a significant benefit: humidity in this range naturally creates anti-viral compounds in the air’s microdroplets.” Among the possibilities they discovered was the transmutation of water droplets into antibiotic hydrogen peroxide when the humidity is within that range. “The results showed that when they increased the humidity from 15% to 50%, the concentration of hydrogen peroxide increased by a factor of 3.5.” At the right humidity there’s three and a half times as much of it.

Earlier research showed that viruses can live in the air, and infect people, for hours or days in low humidity, but at the magic 43 percent humidity and above they die in a few minutes. This does much to explain why our viral epidemics take place in the winter. A 2020 article in Science Connected Magazine summed it up nicely.

“[Researchers] concluded that at room temperature an ideal humidity level for preventing aerosol respiratory viral transmission is a RH between 40 to 60 percent. . . . Research in guinea pigs has shown that when dry air is inhaled, the tiny hair or cilia in our airways are lost, the outer cells lining the airways become detached, and the trachea becomes inflamed.” As a result, the dehydrated mucus is unable to move to where it is needed to trap the airborne pathogens. And you get a sore throat.

With an abundance of evidence showing that humidifying the air can go a long way in keeping us well, we might rightly wonder why we don’t have this hammered into us over and over every year. I have no answer, except the old question, “Cui bono?” — who benefits? Sadly, your getting sick supports many businesses, as you have surely observed in recent years.

But rather than identify the villains, let’s foil their fiendish designs. And the way to do that is to keep the air around us well watered.

It takes more than you might guess. It requires the active promotion of humidity in our homes and workplaces. It can include things as simple as keeping a big pot of water at or near boiling on top of the woodstove. I leave the bathroom door open and point a small electric fan out in the hallway toward the bathroom door when I’m showering. It doesn’t hurt to close the drain when showering and leaving the tub half-full of hot water there, the fan blowing in its direction, after the shower, until it has cooled. It harvests both humidity and warmth.

But those are only partial measures. The shower business can increase humidity temporarily, but air travels into and out of our homes — the leading reason we do not suffocate — so we need to keep adding moisture to the air, constantly.

An abundance of houseplants helps, though not enormously. They are helpful in putting oxygen into the air, and some moisture, but over-watering plants is more likely to kill them than under-watering them is.

For most of us, the answer is humidifiers. There are some that are built into heating systems, but the ones I’ve looked at are unimpressive. Standalone units usually make far more sense. They come in several varieties.

The trendiest are the ultrasonic humidifiers, the ones that produce an attractive plume of fog. I have one of these and it adds to the décor and the humidity, though not by enough. (I love Aldi, the strange grocery store, but had to laugh at the dinky nightstand humidifiers they sometimes sell. They hold a pint or so of water, and for them to do any good you’d have to refill them every 15 minutes.) I’m also a little suspicious of ultrasonic anything. To get water to vaporize that way, they have to be very loud, even though we can’t hear it. They just don’t, okay, sound right.

Popular, particularly for sick rooms, are what are called “vaporizers.” These are typically plastic, with a heating element that sends warm steam out the top. They can be wonderful if you’re stuck in bed with a bad cold — further evidence of the importance of humidity indoors. They usually have little cup in front of the steam spout where you can put a dab of Vick’s Vaporub or some mentholated product made for the purpose. Together they clear your nose and make sleep possible. But they use a lot of power and while they can dispense a gallon of water overnight it’s an expensive way to moisten the air if you use them for that rather than as an aid to recovery from illness. Also, unless you use distilled water they quickly clog with dissolved minerals and stop working.

The best, in my estimation, are what are called evaporative humidifiers. They are a brilliant, simple invention. Whoever invented them should get a Nobel Prize in physics.

Evaporative humidifiers have a tank of water and a big, porous sponge through which air can pass. The water wicks into the sponge and a fan sucks air through it and out into the room. Simple and effective. What makes it so brilliant is that it is self-regulating. The more humidity in the air, the less evaporates from the sponge, the less they need to be refilled, and so on. The warmer the room, the more evaporates (requiring the tank to be refilled more frequently). And because they are simple, they tend to be cheap. Over the years I have had complicated, elaborate ones that one after another broke. The last to go, this year, was a decade-old Holmes device, two and a half feet tall and holding a couple gallons of water. It started to leak, though the source could not be found.

So when I dug out last Friday and went to the store, a humidifier was on my list — I’d rather buy locally if I can.

I was astounded to find simple, sturdy humidifiers, “Pelonis 1 Gallon Evaporative Humidifier,” at Walmart for $20 a pop. They’re the size of a small toaster oven. As the name tells us, each holds a gallon of water at a time. Their only control is a knob that turns the thing on and offers three fan speeds. That’s it. You don’t have to haul the tank around to fill it: There’s a built-in funnel on the top and you just pour water into it. A little bead on the side tells you when it’s full. It can be taken apart to be cleaned as needed, or to replace the sponge thing, which should be done once each season. They, too, have a little cup for “essential oils.” I put peppermint oil in the cup of one of them, because it smells good, aids breathing, and repels mice. It is one of the most elegant designs I’ve ever seen, and when I next go to town if there are still any remaining I’ll get a couple more, just to have.

Based on the frequency with which I refill them I can tell that to maintain 43-45 percent humidity I need to pump about six or seven gallons of water into the air in my house every day. That’s when it’s 20-30 degrees outside and I have the furnace set to 65 degrees, in a house where 800 square feet are open (I close off a few rooms I don’t use in the winter). If it were warmer, I’d have to refill them more frequently.

It would be difficult to overstate how impressed I am with them. (Yes, they’re Chinese plastic things and no, I am not happy about that.)

Nor can I overstate their effect. As my friends will tell you, I have recently been victim to a member of the cold-covid-flu consortium and am not wont to suffer in silence. Within a day of firing up the new humidifiers I was feeling much better and within two days the symptoms were gone entirely. The static electricity has disappeared, so various devices have stopped misbehaving. The fans, the size of extra-large computer fans, are not quite silent, instead making a soft, soothing whirr that I imagine is the sound you’d hear when on a luxurious Stanley Kubrick space ship.

Good in every way. Highly recommended. Especially for those who do not like to feel awful.