When I come home from the grocery store, what should I do with my clothes?

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Here’s yet another surprising effect that COVID-19 has produced in every day life: Stripping once inside the front door has become routine.

As you’ve probably guessed, the motive for rapid disrobing isn’t exhibitionism but fear. After I have gone out in public near other people – which these days means only to the grocery store – I shed the outside layer of clothing and toss it in the washing machine, just in case I’ve carried some coronavirus back with me.

Shedding your clothes in the mudroom is routine for farmers, chimney sweeps, auto mechanics and other folks who wind up routinely filthy, but in those cases the need is obvious. What’s different with coronavirus is that it’s undetectable so you can’t be sure what is necessary.

I want to skip hauling clothes up and down the stairs to our washer and dryer every time I go out to get more beans and rice, so I jumped at the chance to ask an expert.

For the impatient among you, the answer is: Yes, it’s necessary. I can’t use only the dryer, or the microwave, or a UV light; soap is important. Keep reading for details.

The expert in question is Jim Malley, a professor of civil engineering at UNH who has 40 years experience doing disinfection projects using all sorts of stuff such as chlorine, chlorine dioxide, chloramines, ozone, UV light and advanced oxidation processes.

Over the past three weeks he and graduate student Castine Bernardy – working from their respective shelter-at-home locations in Durham and in York, Maine – have been helping rural hospitals develop ultraviolet disinfection systems that can disinfect masks and gowns for reuse, a perfect example of academic expertise pivoting to help real-world problems.

“It’s not something we’d ever do in normal times,” Malley said of reusing medical equipment. But these are definitely not normal times.

Decades of work have shown that the best method to disinfect large amounts of clothing or equipment at once is using hydrogen peroxide vapor. A machine from the non-profit company Battelle being deployed in Boston does this and can handle tens of thousands of masks at a time.

However, this process requires specialized equipment and training, too much for smaller or rural facilities, Malley said, so ultraviolet light is the best bet.

UV light – very short wavelengths, below the visible spectrum – can penetrate masks and damage the molecular bonds that hold together the DNA or RNA of the viruses, keeping them from infecting or replicating within a human cell. It can also kill bacteria.

I actually own a UV wand used to disinfect water from streams when backcountry hiking. You shove it in the bottle of water for up to a minute and then it’s safe to drink. But that won’t work for coronavirus on my clothing, Malley said.

“You need to get three things right with UV: the intensity right, the contact time right, and … the dose distribution correct. It’s much more complicated than a light in a pipe or a light in a room – on Facebook, you’ll see people waving a (UV) light over clothes, but it doesn’t work like that,” he said.

Malley and Bernardy have helped some health-care facilities use commercial units that perform UV disinfection of CPAP masks, or use UV to eliminate unwanted DNA for certain tests.

“The tougher ones are places where they’ve jerry-rigged something. We get them to send us all the details, photos are helpful, and we run the models, give them advice,” he said.

And speaking of advice, what should I do when returning from the grocery store?

Heat breaks down the coronavirus, so I had been hoping that I could get away with tossing clothes in the dryer for 10 minutes at high, skipping the washer.

The problem, Malley said, is that the coronavirus surrounds itself with an envelope of protein that in the right circumstance can protect it, like being covered in a teeny, tiny blob of fat. Soap and water is awesome at breaking down this envelope, which is why it’s so effective for hand-washing. I’d be silly not to make use of it to ensure that no virus lingers, especially since I’m over 60, the age category for 8 of the 9 people who have died in New Hampshire.

“If you were unlucky enough to get a pretty good dose of virus, you don’t want to spread them around the dryer. Hit them with the soap and water,” he said.

So there you have it: I’m stuck with the post-shopping shedding of garments for a while yet.

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on  Twitter @GraniteGeek.)

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