Does a UV sanitizer really work?
January 1, 2010 3:06 PM   Subscribe

Are UV sanitizing wands for real?

I just read a review for a UV sanitizing wand. As a fan of cleaning, an allergy sufferer (dust mites are my worst trigger) and mommy to a toddler, this seems quite appealing. I try to sanitize his toys after he is sick or a playdate and I have pillow and mattress covers, but man, this sounds cool.

Any personal experience or knowledge? (Or is this as iffy as an ionic breeze - makes you feel like something is happening, but in reality, it does nothing?)

Here are some examples:
$90 from Amazon

$100 from Allergy store
$45 Costco
posted by k8t to Home & Garden (15 answers total) 3 users marked this as a favorite
I don't know anything about these wands, but using UV as a sanitizer is definitely for real -- I've used a UV water filtration system to make drinkable water from lake water. It's entirely enclosed though, and whether that continues to work in a wand you wave around I don't know.
posted by brainmouse at 3:20 PM on January 1, 2010

A work we have bio-hoods with UV lights that will cheerfully give you a sun burn. You use these by turning them on and walking away for 15 minutes or so. I can't imagine a cleaning wand that will both kill germs with the wave of a wand and not cause damage to your eyes.

Unless someone has evidence to the contrary, my suspicion is that you'd probably be better served to get a UV HEPA filter that kills whatever the filter collects over hours, down in the bowels of a machine where it won't burn your eyes right out of your head.
posted by Kid Charlemagne at 3:33 PM on January 1, 2010

Reading the blurb on that Amazon product, the wand is clearly capable of causing eye damage — it has an orientation sensor so that it can turn itself off if it's not pointing downwards.

It seems plausible in principle, although whether it will actually kill dust mites deep inside bedding material I have no idea.
posted by pharm at 3:43 PM on January 1, 2010

Response by poster: Other reviews recommend wearing UV-C blocking sunglasses while doing this...
posted by k8t at 3:47 PM on January 1, 2010

Yeah, germicidal UV is a standard sterilization method in labs that work with biological materials. It's dangerous, though. You can burn your skin and damage your eyes if you're not careful.

The thing that strikes me about these wands is that you'd have to be awfully fastidious about how often you use them and how thoroughly you cover the area you're trying to sterilize. And, of course, they can't penetrate UV-opaque materials like bedding; they seem optimal for smooth surfaces.
posted by mr_roboto at 3:59 PM on January 1, 2010

Best answer: These wands sound bogus to me. If the UV radiation coming out of the emitter is high enough to kill bacteria and viruses, it will be strong enough to damage your skin and eyes. If the wands are safe enough to use unshielded, then they're not going to be doing much (if anything).

Now that said, I've used a portable UV-C device for water purification. Their website describes how they're using UV-C, which is what those devices claims they emit.
The entire band of UV light is about as broad as the entire visible spectrum — it runs from 400nm to about 100nm. The UV band is divided into 3 ranges: UV-A between 400nm and 320nm, UV-B between 320nm and 290nm and UV-C between 290nm and 100nm... UV-C light destroys DNA and thereby prevents microbes from reproducing.
In their safety disclaimers, they take great pains to point out how one will never come in physical contact with the UV-C radiation.
Exposure to ultraviolet light can cause skin and eye damage ... UV-C will not pass through most materials. Drinking containers made from glass, ceramic, metal, and nearly all plastics block UV-C transmission. Also, the underside of the air/water interface in a water container acts as a very effective reflector for UV-C. As a result, when [the devices] lamp is immersed in virtually any drinking vessel, the UV-C is well contained.
posted by cheez-it at 4:00 PM on January 1, 2010

I use UV sterilization in a industrial setting and it's for real. But, you need lots of power to do it quickly and there are always safety interlocks to prevent you from actually being exposed to the light since it's dangerous to your vision. The little hand held ones can't possibly be putting out enough UV to be a danger to humans so I'm certain they're mostly useless for killing germs and certainly totally useless for killing anything bigger like mites.
posted by Confess, Fletch at 4:07 PM on January 1, 2010

This sounds like one of those things where a valid industrial process--sterilization with ultraviolet light--is being sold as a consumer good--ultraviolet "wands."

It seems a safe assumption that miniaturizing an industrial process into something that can be held in the hand by a consumer is a path fraught with overstated claims.
posted by dfriedman at 4:26 PM on January 1, 2010

Best answer: Relevant wikipedia article. The key issues here are that UV sanitation relies on line-of-site exposure and, of course, that it is also harmful to humans. I would not count on it to sanitize bedding (beyond the outer layer) as some of your links claim. As far as I have read, germicidal UV will successfully kill bacteria within minutes but fungal spores may take half an hour or perhaps even survive UV exposure. So it's not total bunk but I wouldn't buy something like this. It would be too dangerous to sell to the general consumer or too ineffective once they make it safe enough.
posted by bobobox at 5:22 PM on January 1, 2010

Then, too, there is the question whether cleaning and sanitizing to such an extreme is really a good idea. If your toddler grows up in a sanitized environment, his immune system won't learn what germs are out there, and won't be prepared for an onslaught. Read about the hygiene hypothesis here.
posted by exphysicist345 at 5:50 PM on January 1, 2010 [5 favorites]

Response by poster: Exphysicist, I'm with you, but trust me, after having your kid out of (non-refundable) daycare and missing work, you gotta stop the cycle. We've gotten too many 'oops sorry' emails about a kid with hand, foot and mouth after he chewed on my kid's favorite teether.

Trust me, I'm not wiping up with Clorox wipes at every turn, but there is a time and a place for sanitizing.

Plus I sanitize toys before giving them away and after I buy used ones at garage sales/Craigslist.
posted by k8t at 6:44 PM on January 1, 2010

Response by poster: Also, with the amount of sterilizing I have to do for breastmilk pumping and storage, I could use a speedy sanitizer.
posted by k8t at 6:55 PM on January 1, 2010

The time it takes is based on the power of the bulb. A bulb that CAN kill off a majority of germs and viruses WILL burn you, like a sunburn. But they are proven.


"Intensity X Exposure Time = microWatts Second/cm2"

Intensity of the light decreases over distance, so you have to put the light pretty darn near the surface you want to disinfect. Remember how sunlight can bleach or pale your curtains? Imagine this on your carpets. Don't want to do it too often to a surface that is delicate as far as decomposition due to UV exposure.

To determine the ultraviolet intensity of one 37 microWatt bulb rating at one meter distance held 6 inches from the item: (The intensity of this bulb at 6 inches distance is 20.)

So 37 X 20 = 740 microWatts/cm2

At this rate, in order to kill an influenza virus, the lamp must be held at 6 inches from the area for about 8.5 seconds. (99% kill rate of influenza virus is 6600 mW S/cm2).

So yes, it DOES work, it's great for 'cleaning' air in air ducts. Cleaning surfaces with it could prove problematical, but the toothbrush ones do work as well.
posted by Jinx of the 2nd Law at 7:57 PM on January 1, 2010

"...and mommy to a toddler, this seems quite appealing. I try to sanitize his toys after he is sick or a playdate"

Bad idea. Exactly the non-exposure to allergens may easily trigger allergies!
posted by yoyo_nyc at 7:45 AM on January 2, 2010

We live in a world full of bacteria, most of them neutral. There are harmful bacteria in too many of our foods, notably eggs, ground beef and chicken. In our global village, viruses travel around the world in a short time. Mucus from a sick person and fecal matter are generally full of harmful bacteria. My point is that it's pretty straightforward to protect yourself from bad bacteria. Prepare eggs, chicken and ground beef with care, clean up well after. While interacting with others, wash hands, and keep hands away from eyes, nose and mouth. Wash hands after using the bathroom and after handling dirty laundry. Get your child appropriate vaccinations.

If children are routinely getting sick at daycare, the day care provider needs to do a better job of sanitizing toys, and keeping sick kids home.

All sorts of vendors make money when people feel the need to rid their homes of bacteria. Sunshine and fresh air are your best friends. Keep your house reasonably clean and stop watching ads that freak you out.

American children are at risk of illness from lack of exercise, lack of sunshine, and lack of time spent outdoors. Give your child the gift of adventure and play.
posted by theora55 at 2:44 PM on January 2, 2010

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